Tuatara
New Zealand
Volume30
December1988
Contents
Editorial
This issue marks a change in Tuatara. From now on we will be publishing a single annual Volume of similar size, or larger, than the combined size of the two (or three) parts per Volume, published previously. This brings Tuatara “into line’ with similar publications and reduces printing costs. As Editors, we find it easier too, to produce a single annual issue, especially as there is a tendency for the bulk of the papers submitted to arrive at one time of the year! We very much appreciate the loyalty of our subscribers and hope that the change will be welcomed.
We record, with great regret, the sudden death of Byron Buick-Constable (aged 43) on 5 November, 1988. Mr Buick-Constable, the Assistant Registrar (Information and Publications), Victoria University of Wellington, has for many years, been Business Manager of Tuatara and we are grateful for the care and enthusiasm which he devoted to the publishing of this journal.
New Zealand Geological Survey, P.O. Box 30 368, Lower Hutt.
Abstract
Forensic palynology has the capability of proving or disproving alibis; connecting suspects to the scenes of their crimes; connecting an item or items to either the scene of the crime or to suspects; and sourcing items, including drugs, to their point of origin. A brief history of one of the earliest New Zealand cases, involving the theft of deer velvet, is presented as an illustration. Palynological evidence given in this case is summarised and placed in context with other evidence.
Key words: Forensic palynology, palynology, criminology, pollen assemblages, case history, deer velvet, New Zealand.
Introduction
The objective of this paper is to present evidence of the usefulness of palynology in forensic science (Mildenhall, in press), with particular reference to New Zealand.
One scientific term that is unavoidable is “palynology”. Palynology is the study of spores and pollen, the very small fertile bodies of all plants, usually disseminated by air. The term pollen assemblage refers to the total range and relative numbers of different types of spores and identified plants to avoid confusion over the use of common names, which often apply to different types of plants in different countries.
A pollen sample is obtained by acetolysis, which entails heating the rock or soil sample with a mixture of one part concentrated sulphuric acid and nine parts acetic anhydride. The organic material is then separated by centrifuging, floated off and mounted on glass slides ready for examination under a high-powered microscope. The exact technique varies with the material to be analysed; acetolysis is not used if viable pollen is to be studied.
Palynology has proved useful in a number of forensic cases over the past ten years, although not all cases have come to court. Both New Zealand Geological Survey and Botany Division (Department of Scientific and Industrial Research or (Dsir) have been active in this field. New Zealand Geological Survey's involvement in forensic palynological work has been the result of a number of factors. Firstly we are close to Chemistry Division (Dsir) in Lower Hutt, where the bulk of New Zealand's forensic science is carried out and it is but a simple matter, and easily demonstrated in court, to pass samples from hand to hand without recourse to couriers. We are therefore able to work closely with the other forensic scientists involved in each case. Secondly, New Zealand Geological Survey provides a forensic petrological service and in many cases it is logical to provide a palynological service in the same laboratory at the same time. This avoids problems of explaining continuity of sample handling, a bugbear of many court cases, since it must be always quite clear where individual samples were at any instant during an investigation. Thirdly, our staff of four palynologists have expertise in a variety of palynological fields which are of potential use to the Police. Finally, we have been able to build up a case file from experience gained in the field over the last ten years.
The purpose of palynological evidence is to attempt to identify and then correlate spores, pollen and other acid resistant organic materials at the scene of a crime, or on a suspect, with each other. In essence we try and determine the relationship between a suspect and the scene of a crime, by linking an item left at the scene and a suspect, or an item at the discovery scene with the scene of the actual crime. We also attempt to disprove or prove alibis, and source items to their point of origin. Palynology can also be useful in cases of suspicious death where poisoning is thought to be involved, particularly with botulism and honey poisoning, although this is more the role of the medical profession. There are many problems with forensic palynology and some of these are briefly mentioned in Mildenhall (in press).
Forensic palynology is a relatively new science. Erdtman (1969) in a chapter headed “pollen analysis and criminology” described several ways in which palynology has solved crime, including a murder investigation in Vienna, Austria, in which a unique combination of spore and pollen types on a suspect's shoes pointed to the scene of a murder, even though at the time the body of the murdered person had not been discovered. The diet of a murdered person can sometimes
Case History: The Case Of The Stolen Deer Velvet
This case history involves the theft of deer velvet (antlers in a soft state). Some mention of the case has already been made in the literature by Mildenhall (1982), Skinner et al. (1988), and Mildenhall (in press). This description of the case in greater detail permits the role of forensic palynology to be placed in context, as well as confirming that it is only one of a series of techniques that are available to the courts in seeking out the truth.
On 27 February 1980 the Police executed a search warrant and seized a large quantity of deer velvet from a suspect's house. The deer velvet was later identified as having been stolen three months previously from Ohinepaka Station, Wairoa. The velvet was found in a freezer in a garage at the suspect's home and weighed 37.5 kg; the original amount stolen was estimated to be over 100 kg and worth about $16,300. The suspect was charged with stealing the velvet on 23 November 1979 and an alternative charge of receiving 66 pieces of deer velvet between 23 November 1979 and 26 February 1980 was also laid. The suspect denied the charges and maintained that the velvet had been colleccted by him over two seasons and was being stored until the price of velvet, which was low at the time, rose. The suspect elected trial by jury.
The theft was first noticed by the manager of the deer farm on the 23 November 1979, when a large amount of velvet was found to be missing from a padlocked freezer on Ohinepaka Station. Also missing was a wool bale sack, which had been covering the floor of the freezer, and a quantity of sausages. The stolen material consisted of 97 kg of A (= first) grade and 20 kg of fourth grade velvet, some of which had distinguishing marks caused by the cutting equipment used at the time to cut the antlers off the farmed deer. These distinguishing marks were found on some of the velvet located in the suspect's freezer. Moreover, string marks on the antlers were consistent with those left by the manager's method of hanging the antlers in the freezer at Ohinepaka Station.
One of the stolen antlers had come from an animal that the manager had been keeping a close eye on because it had an unusually shaped antler with a break at the base. Furthermore, some of the antlers still had string attached, consistent with string used at Ohinepaka Station. A wool bale sack, similar to the one stolen from the station, was found in the corner of the suspect's garage.
The high quality of the velvet recovered was regarded, in part, as being due to the method of storage. The velvet recovered was found stacked in a small freezer, but if the antlers had been frozen in that position from a soft state then identations would appear on the velvet. These indentations were not apparent on the recovered velvet. It was quite clear that this velvet had been frozen individually by hanging in a large freezer, attached by string. In the event of thawing and being refrozen some marks would be apparent on the antlers. Stags grow antlers annually, and being at their most valuable state when soft, the antlers are usually harvested about sixty days after the commencement of growth, in November through to
Since the suspect maintained that he had obtained the antlers over a period of two years hunting in native bush, and that he had carried the velvet out attached to his belt, it was difficult to see how the velvet could have been of such high quality, since some damage would be unavoidable considering the stated method of transport. Experienced hunters giving evidence at the trial confirmed that the method of carrying velvet, as stated by the accused, would cause much damage and that hunters would normally carry velvet tucked down the front of their jerseys or well wrapped up, because “it was like gold and has to be well protected”. Considering the suspect's statement that he had collected the velvet over the previous two seasons, further evidence from experienced hunters indicated that, because the harvesting period for velvet was so short, the amount of velvet seized by the Police was too great to have been collected in a two year period of time from free ranging deer. The hunters also maintained that it would be impossible for one man hunting alone to get 18 kg per month and that most of what was obtained would be well below A grade quality. It was estimated that a total of only about 20 velvet carrying stags would be shot in the area per year, averaging three animals per week for a full time hunter, at an average weight of about 1 kg of velvet per stag.
Evidence also presented suggested that velvet was usually cut off free ranging deer by sawing, not cutting and that tourniquets were not normally used when collecting velvet from free ranging deer killed in the wild. The suspect explained the existence of the string and string marks on the velvet by stating that he had applied a tourniquet to the antlers immediately after cutting them off with bolt cutters or a saw (which he could not produce in evidence) in order to stop blood loss. He also maintained that the string had been given to him, along with the wool bale sack, by an employee from a local Lands and Survey farm.
The police recovered 66 pieces of velvet in total, but of these only 10 matched in colour and development, indicating that they had came from the same five deer. If the suspect had done his own harvesting then a higher degree of pairing would have been expected. This was explained by the suspect as resulting from damage to some antlers when the animal fell to the ground after being shot, and the damaged antlers being left in the bush. However, experienced hunters stated that all velvet was of some value and that it was most unusual to leave damaged antlers after the effort of shooting the deer.
Evidence was also presented from an agent for a velvet-buying company, who examined the recovered velvet and maintained that it could only have come from animals growing in a very good environment, possibly pasture. This was on the grounds that animals from the wild always have a percentage of malformed or damaged velvet, and that only about 25% of deer velvet collected in the wild would be of A grade quality. This witness estimated that the antlers examined contained well over 60% A grade velvet, while another witness put this figure at 90% A grade velvet.
Forensic scientists from the DSIR were called on to examine the velvet, wool bale sacks, twine, wool bale string, and the cutters used at Ohinepaka Station to remove the velvet from the deer. The scientists were unable to confirm that the
A quantity of dung was found on one of the stolen antlers. Examination of the material indicated that it came from an animal that fed off pasture grass and not on bush vegetation.
Six soil samples were collected from the deer pens, two samples from inside and outside the stolen wool bale sack, one sample from a wool bale sack at Ohinepaka Station and three samples from three separate antlers found in the suspect's freezer, one of the samples coming from the base of one of the deer antlers. Petrological examination of all 12 samples showed that they contained minerals and rock fragments consistent with coming from a similar source, and that they all contained a large amount of organic matter that appeared suitable for pollen analysis.
The twelve petrological samples were also examined palynologically, and the plants from which the spores and pollen came from were identified in ten cases. However, two of the samples, from material adhering to the stolen antlers, did not contain any spores or pollen. All ten samples were consistent with derivation from a cultivated grassland source and no sample contained evidence of having been derived from a forest or bushland environment. The similarity of the pollen assemblages from the stock pens and the wool bale sack at Ohinepaka Station with those on the stolen wool bale sack and on the base of one of the stolen antlers suggested that they were derived from a very similar source. The combination of spore and pollen types suggested that the farm on which the stock pens occurred was the original source of all samples. It was impossible for the samples to have come from a grassy clearing in bush or forest as the pollen assemblage from the clearing would have been dominated by pollen from the surrounding trees. The percentages of spores and pollen, given below, could not be derived from soil samples cultivated plants suggested derivation from a cultivated area in which both exotic and native plants occurred together (Table 1).
As can be calculated from the above list, up to 84% of the total pollen count consists of pollen from Gramineae (grasses) and Compositae (daisies). Other plants rarely form more than 4% of the count. The samples do show some variation, but no more than is to be expected from mud collected from stock pens, where ground is constantly stirred up and often muddied by animals brought in from outside the immediate area. What the samples do show are that they are all derived from a grassland environment and that both native and exotic plants grew in the area, but not in any great abundance and not very close to the stock pens. The variations that appear in the percentages of the more infrequent plants are in part caused by the very low counts done at the time, ranging from 137 to 210
A few spores and pollen were not idenfified, as these were from exotic (not native) plants not represented in our spore/pollen reference collection. However, this does not negate the fact that the samples, within the limits of the palynological tehnique, were very similar, and all came from the same environment.
A point to be stressed about the sample from the base of the antler found in possession of the suspect is that the mud sample was mixed with blood. This indicated that the spores and pollen in the mud and the blood arrived on the antlers at the same time, while the blood was still wet. This time must have been immediately after the antlers were cut. and since the mud contained pollen from a grassland environment they could not have been taken from free ranging deer in either native or exotic forest or bush.
There are one or two intereting aspects of the plants identified. The sample from the inside of the stolen wool bale sack contained pollen that could only have come from soil or rocks greater than one million years old. This sample contained pollen of Casuarina (she-oak, a plant now growing in Australia and Polynesia), Nothofagus brassi beech (large leafed beech growing today in New Caledonia), and fossil Proteaceae (proteas). This distinct difference from the other samples could be explained by the fact that the wool bale sack would have been used a number of times and had in the past carried material containing mud or rock fragments containing extinct pollen types. These pollen types were of a different colour from the more recent grains, which were light in colour and better preserved.
Another feature was the variety of liverwort spores identified from the stock yards and the mud/blood sample from the base of the antler found in possession of the suspect. Such a variety is unlikely from a sample taken from a clearing in bush or scrub. The plants involved suggested a permanently damp and muddy situation, such as stock pens usually are, although a similar situation would occur on muddy banks of streams. Inspection of the stock pens confirmed that they were muddy and that liverworts were growing around the fence lines. There was also a number of native and exotic plants growing in the area whose pollen was represented in the soil samples.
Finally, pollen of a number of plants occurred that would be unexpected in an upland forest or bush situation. For instance, Salix (willow) is common around streams and on farms; Juglans (walnuts) is often found on abandoned farms and settlements now overgrown, but still is unlikely in upland areas. The pollen of native plants identified from the samples are wide ranging types that could well have come from nearby native forest, but the low abundance shows that the forest was a considerable distance away. These pollen types usually overwhelm pollen from herbaceous plants, which do not produce pollen in the abundance that forest trees do.
After five hours of deliberation the jury found the suspect guilty of receiving the deer velvet, and since the police could not present any evidence as to who had committed the initial theft, that charge was dropped. The judge in his summing
Conclusion
This is but one case in which palynology has assisted a jury in coming to a verdict in a criminal action in New Zealand. In most situations the evidence is circumstantial, either showing that a suspect's alibi is highly improbable, or showing that a suspect, or something connected with a suspect, came from an environment similar to that in which a crime had been committed (Mildenhall, in press). Not all the palynological evidence presented above is produced in court in the form of verbal testimony. Palynological data by their very volume present problems of presentation, and concentration on the environment that the samples come from, and on certain key plants, relieves the palynologist of having to explain insignificant differences between pollen assemblages examined. All data are, however, available to both defence and prosecution and this allows the material to be challenged, since data a palynologist thinks are insignificant, may turn out to have a significance not previously realised. The defence can also get alternative opinions based on the list of identifications and pollen counts. It should be realised that only the list of plants and the counts represent factual data; the rest is interpretation and opinion and as such can and should be challenged.
Acknowledgments
The various drafts of this paper were read by Geoff Gregory, Ian Raine, David Skinner and Graeme Wilson (New Zealand Geological Survey), to whom I am most grateful. Thanks are extended to Bruce Sampson (School of Biological Sciences, Victoria Univertsity of Wellington) for his encouragement in this project.
References
Handbook of palynology. An introduction to the study of pollen grains and spores. Hafner Publishing Company, New York. 486 pp.
Science 190:443-451.
Geological Society of New Zealand newsletter 58:25.
New Zealand Geological Survey report G130:13 pp.
Lindow man: the body in the bog. British Museum Publications, London, 208 pp.
Fig. 1Photomicrograph of Cannabis (cannabis). These pollen grains are often found associated with hashish (cannabis oil and resin), in soils close to groves of flowering cannabis, and on the clothes of people cultivating cannabis plants. X 1000.
Fig. 2.Photomicrograph of Artemisia(sage brush). The pollen grains are often found associated with imported hashish. X 1000.
Fig. 3.Photomicrograph of Impatiens(balsam or water fuchsia). These pollen types suggest a tropical or northern hemisphere source for imported drugs. X1000.
Fig. 4.Photomicrograph of Foeniculum(fennel). A pollen type found regularly in forensic palynological samples. X 1000.
Fig. 5.Photomicrograph of Salix(willow). A pollen type found regularly in forensic palynological samples. X 1000.
Fig. 6.Photomicrograph of Ribes(gooseberry). These pollen types were found in surface samples around and underneath a body, but were not found on mud on top of the body. This, along with other evidence, proved that the mud on the body came from some other source, and that the body, along with the mud, had been taken to the site after death. X 1000.
Fig. 7.Photomicrograph of Alnus(alder). These pollen types are often found in drugs and other items imported from the northern hemisphere. X 1000.
Fig. 8.Photomicrograph of Eucalyptus(eucalypt). These pollen types are very common in forensic samples. X 1000.
Fig. 9.Photomicrograph of Acacia(wattle). These pollen types are thought to disperse only short distances from the parent plant. Therefore their presence in forensic palynological samples indicates that the tree occurs close by the source of the samples. Such evidence can assist towards sourcing items to particular sites, and this pollen type, along with other evidence, assisted in sourcing the stolen deer velvet to Ohinepaka Station. X 1000.
Fig. 10.Photomicrograph of Juglans(walnut). These pollen types have assisted towards sourcing forensic palynological samples by suggesting that sites lacking in walnut trees could not have been the source. This, along with other evidence, assisted in sourcing the stolen deer velvet to Ohinepaka Station. X 1000.
Department of Botany & Zoology, Massey University, Palmeston North, New Zealand.
Key words: Hepaticac, Metzgeriales, Fossombronia australis, Fossombronia pusilla, Fossombronia reticulata, Fossombronia wondraczekii.
Abstract
The main features of the genus Fossombronia are outlined. Taxonomy, morphology and distribution of F. reticulata, F. australis, F. wondraczekii and F. pusilla are reported. Notes are given on other species recorded for New Zealand.
Main Features of the Genus Fossombronia
Fossombronia Raddi is classified in the family Codoniaceae of the Metzgeriales (Grolle. 1983) which is a predominantly thalloid order of the Hepaticae. Fossombronia is unusual in that is shows two rows of lateral thallus lobes which are leaf-like and are normally called leaves. These are, however, quite different from the leaves of the so-called leafy liverworts, Jungermanniales, so that despite its leafy habit Fossombronia is unlikely to be confused with any member of that very large order. The prostrate fleshy stem, bearing reddish rhizoids, is also distinctive for most Fossombronia species.
The stem is more or less plane dorsally and convex ventrally. Internally the cells are uniformly thin-walled. The leaves are obliquely inserted with the antical margin decurrent. They tend to be crowded towards the stem apex and vary in shape even on a single stem, but are usually broader than long and have an irregularly undulate, lobed outline, with a few scattered mucilage papillae on the margin. In structure the leaves are for the most part unistratose but at the base become pluristratose. Individual cells are uniformly thin-walled and gradually increase in size, particularly in length, towards the base of the leaf. In all New Zealand species they contain chloroplasts and a variable number (4-40) of ellipsodial oil bodies, 1.8-2.6 × 4-4.8 μm. At a magnification of x100 the oil bodies appear smooth and glistening but at x500, using Nomarski interference microscopy, they appear botryoidal with a single eccentric large spherule. They resemble the oil bodies of Lophozia silvicola (Schuster, 1966; Fig. 13.9).
As regards sexual reproduction the species are either monoicous or dioicous. The young sporophyte is enclosed by a thin calyptra and by a more conspicuous campanulate pseudoperianth. Further protection may be provided by the crowded terminal leaves. The capsule is spherical and has a bistratose wall with the inner layer strengthed by nodules and irregular incomplete rings of thickening.
It is widely recognised (Scott, 1985) that, since species of Fossombronia vary considerably in morphology, according to environmental conditions, reliance cannot be placed on vegetative characters for separating them, particularly if herbarium specimens only are available for examination. However, should spores be present, the size of these, together with the ornamentation pattern on the surface, has proved to be distinctive for most species, even though ripe spores have been found to undergo post-harvest shrinkage and so are slightly smaller than those freshly shed.
Distribution
As far as is known F. reticulata is endemic to New Zealand. It is widely distributed throughout the country. Recent collections are from stream banks near Norsewood, roadside banks on Banks Peninsula and in the Akatarawa Range, and drain banks at Massey University. It also occurs as a weed in some bowling greens.
F. reticulata was described in Latin by Stephani (1984; 1900) from a specimen collected near Auckland, New Zealand by T. Kirk and now housed in the Stephani Herbarium at Geneva. A syntype is at CHR. The type and syntype were examined as well as other specimens from the collections of E.A. Hodgson,
Plants from recent collections were cultured at Massey University on a sterilised clay soil in plastic containers and observed over three years.
Plants tend to grow in tufted, yellowish-green to green cushions, up to 20cm in diameter. Individual shoots, 1-5cm long, are terminally erect but basally prostrate and attached to the soil by numerous long crimson rhizoids. The breadth of the shoot including the leaves is up to 6mm. Branching is intercalary with new shoots arising in a supra-axillary position and usually from the basal part of the plant.
The stem region, 0.9mm broad and 0.26mm deep, consists of the thin-walled cells of width 40-60 μm, depth 40-60 μm and length 120-230 μm. The leaves are of firm texture, 2-(3)mm long and 2-2.5(-4)mm broad, widely spreading to suberect, either distant or slightly imbrticate, execept where they are crowded near the stem apex, more or less crisped and rounded with 2 to 4 shallow lobes, which on the margin may show one or more angular projections, each terminated by a mucilage papilla. Except in very young plants the leaves tend to be opposite to subopposite with the antical margin long decurrent.
Plants are dioicous. In male plants numerous antheridia occur on the upper surface of the stem amongst the terminal leaves (Fig. 1a). Each anteridium has a short stalk and a spherical head, 0.21mm in diameter, which is often conspicuous by its yellow colour but with age becomes whitish. In female plants (Fig. 1b)
Fig. 1 Fossombronia reticulataA. Male shoot showing antheridia. b. Female shoot showing sporophyte and pseudoperianth. Drawing by C.A. Korndorffer.
Note:F. reticulata is proving to be a troublesome weed in some bowling greens and golf courses, apparently favoured in comparison to more desirable plants by some spray programmes. Research is currently being carried out in regard to this.
It has been observed that, after the spraying of roadside banks on the Akatarawa Road with 2,4,5-T F. reticulata was one of the first plants to appear. The green cushions were very conspicuous on the bare clay soil. Investigation showed that, although the spray had killed the parts of the Fossombronia with which it came in contact, it evidently was not translocated within the plant, for new shoots rapidly developed either from resistant apices or advenitiously from stems that were underneath the cover of dead leaves.
Fig. 2Spore ofF. reticulata.Top:distal view.Middle:side view.Bottom:proximal view. Scanning electron micrographs by D. H. Hopcroft and R. Bennett. Scale bars = 10 μm.Fig. 3Spore ofF. australis. Top and Middle:distal view taken from different angles.Bottom:proximal view. Scanning electron micrographs by D.H. Hopcroft and R. Bennett. Scale bars = 10 μm.
Distribution
Fossombronia australis is known from Kerguelen Island and from New Zealand. The type came from Heard Island in the South Indian Ocean (Bonner, 1965). It may occur also in Australia, although records from that country require confirmation from a wider range of specimens. In New Zealand it grows either amongst other vegetation on wet, shady banks or as dense, partially submerged colonies in freshwater swamps and Sphagnum mires.
This species was described by Mitten in 1876 from specimens gathered in Heard Island by H.N. Moseley, naturalist to the Challenger Expedition. The specimens were without fruit (Mitten, 1876a). Further on in the same journal there is another description of F. australis by Mitten, this time from specimens with young capsules, which were collected in Kerguelen Island at Royal Sound, Vulcan Cove by A.E. Eaton (Mitten, 1876b). Three years later Mitten again described F. australis (Mitten, 1879) and listed the distribution as Kerguelen Island, Moseley; Royal Sound, Vulcan Cove, with young capsules, Eaton; (Heard Island) Moseley.
Stephani (1900) gave a description of F. australis and that the spores described by Mitten were spore mother cells; he questioned whether they belonged to this species. He gave what he considered to be a correct description of the spore, based on a few still retained in a capsule. They are said to be 32 μm in diameter and densely covered with short truncate papillae. However, his description of the leaf appears to be from a poorly preserved specimen. The distribution is given as Kerguelen (Eaton), New Zealand (Colenso). Stephani also made drawings of the spore, elater and leaf of F. australis. The last of these shows the shape, vertical orientation and deep grooves typical of the species.
Immediately following the description of F. australis and in the same subdivision of the genus, Stephani (1900) described F. gigantea n. sp. This name in my opinion is a synonym of F. australis (see later).
Specimens in the Mitten Herbarium collected from Kerguelen Island by Eaton and by Moseley were examined at the Herbarium of the New York Botanical Garden. No spores are present and all appear to be male plants. Specimens from New Zealand were identified in the collections of E.A. Hodgson and of
Plants grow in colonies of a predominantly yellow-green colour, often merging into reddish at the bases of the leaves and into reddish-brown in the stems and older parts. At times the whole plant is reddish-brown. Individual shoots branch a few times and are large, being up to 5cm long and 13mm wide including the leaves. When growing on banks the shoots are prostrate and attached by reddish rhizoids, but when growing in mires the shoots are erect and apart from emergent tips are submerged, with rhizoids either very short or lacking. The stem is 1-1.5mm broad and 0.3-0.5mm deep. The older leaves are large, 2.5-4mm long and 5-8mm wide, alternate, closely imbricate, in overall shape reniform, distally deeply folded
Plants are dioicous. In male plants about 10 to 12 antheridia are found dorsally on the stem, arranged so that there are 1 to 4 in the vicinity of each leaf. The antheridium has a short stalk and a spherical head about 0.3mm in diameter. In female plants archegonia appear amongst the terminal leaves but due to continued growth of the stem the sporophytes become located dorsally. The campanulate pseudoperianth is large, up to 6mm long and 2mm across the shallowly lobed rim. It is partially enclosed by the adjacent leaves. The brown spherical capsule, of diameter 1mm is elevated on a firm stalk up to 11mm high. The golden-brown spores (Fig. 4) have a diameter of 29-37 μm. The distal face is described by Stephani (1900) as being densely muricate with low papillae, but when viewed from some angles the projections appear more as irregular short lamellae. On the proximal face the lamellae are lower and more crowded. The elaters are of two kinds. Most are slender. 5 × 145 - 225 μm, with 2 helical bands of thickening; others are shorter and wider, up to 13 × 100 μm, with 3 or 4 bands.
Distribution
This species is widespread in Europe and North America and has been reported also from North Africa (Bonner, 1965) and from Australia (Scott, 1985). A taxon from Japan has been called F. wondraczekii var. loitlesbergii (Inoue, 1973). F. wondraczekii has not been recorded for New Zealand previously but has now been found in the Wairarapa, on banks in pasture country in Hawke's Bay, in the Kaingaroa State Forest, and in Northland.
It is commonly found on bare soil, as in cultivated fields, on infrequently used paths and at the margins of drains.
Stephani (1900) provided a Latin description of the species under the name F. cristata Lindb. (misprinted as crispata in the text). A more recent description in English is given by Scott (1985) and earlier shorter ones by Mueller (1906-11) and by Frye and Clark (1937). They also provide illustrations, as does Landwehr (1980). The fresh material used in the present study was collected by D. Havell from small silty knobs on the edge of Lake Wairarapa on 15:1:1987. It was later maintained in culture at Massey University. Herbarium material was examined from the collections of E. A. Hodgson, from Botany Division, D.S.I.R., and from Europe.
The rather delicate, bright green plants occur singly or as small patches and are attached to the soil by violet rhizoids. Individual shoots may be simple or may branch once or twice; they are up to 2cm long and 2-3mm wide. The stem is up to 1mm wide and 0.7mm thick. The leaves are longitudinally inserted, opposite, or almost so, and crowded towards the tip of the stem, but alternate and varying further back. They range from 1 to 3mm in both length and breadth and vary in overall shape from oblong to quadrate. They may be either plain or crisped at the margin, entire or variously lobed, with the lobes frequently acute.
This species is monoicous. Archegonia are scattered on the dorsal surface of the stem and whitish antheridia occur nearby among the apical leaves. The pseu-
Fig. 4Spore ofF. wondraczekii.Top:distal view.Middle:side view.Bottom:proximal view. Scanning electron micrographs by D.H. Hopcroft and R. Bennett. Scale bars = 10 μm.Fig 5.Spor ofF. pusilla.Top:distal view.Middle:side view.Bottom:proximal view. Scanning electron micrographs by D.H. Hopcroft and R. Bennett. Scale bars = 10 μm.
Sometimes the lamellae show a tendency to merge into areolae at the centre of the distal face. The proximal face is papillate to feebly lamellate. Spore diameter is rather variable, the range being (40-) 45-47 (-52) μm. Elaters are simple or occasionally V-shaped or forked, 8-9 (-13) μm wide and 50-80 (-105) μm long, usually with 2 helical bands but occasionally with up to 4.
Distribution
This is a cosmopolitan species. It is found in similar sites to F. wondraczekii such as damp clay soils and the sides of drains. In New Zealand the two species may even be intermixed. It has been recorded for New Zealand by Gottsche, Lindenberg and Nees (1844-7), by Mitten (1855) and by Allison and Child (1975).
The species has been described and illustrated many times since Linnaeus (1753) called it Jungermannia pusilla. Recent treatments are by Scott (1985) based on Australian material, by Paton (1973) and Landwehr (1980) for European material and by Allison and Child (1975) for New Zealand material. Scott noted that there is a considerable degree of variation between populations. Paton (1973) recognised two varieties and these occur also in Australia (Scott, 1985). So far only var. pusilla has been found in New Zealand.
Fresh material was collected and studied in Europe and from the sides of the drain opposite Woodville Reserve, New Zealand. Herbarium material was examined at the British Museum, the Senckenburg Herbarium, Frankfurt and in the collections of E. A. Hodgson, of Botany Division, D.S.I.R. and of the National Museum, New Zealand.
Plants grow singly, in scattered patches or in large colonies. The bright green, prostrate shoots are 1-1.5cm long, either simple or once to twice branched and attached to the soil by numerous violet rhizoids. The stem is slender, being 0.5-2mm wide and 0.4-0.7mm thick. The leaves are inserted obliquely and vary in orientation from transverse to longitudinal, and from plane to crisped at the margins. They also vary considerably in shape but in general are reniform, 0.8-2.6mm long and 0.8-4.4mm wide, and may be entire, emarginate or irregularly lobed and angled.
Plants are monoicous. Antheridia appear first and are conspicuous on the upper surface of the stem by their yellowish colour. Later archegonia appear on the upper surfacce of the stem near the apex. Sporophytes are produced in abundance. Each has a short, fragile stalk about 3mm high and a brown spherical capsule of diameter 0.8mm. The companulate pseudoperianth is 2-3mm high and up to 3mm wide across the rim which is irregularly scalloped and often somewhat crisped. The spores (Figs. 5 and 6) have a diameter of about 50 μm (42-56). The distal face is ornamented with forking or radiating lamellae which sometimes join to form an ill-defined, or rarely a complete, network. They appear in profile at the
The type specimen (G. 22170) which was used by Stephani in drawing up the Latin description (Stephani, 1900) was collected in New Zealand by Knight. It is now housed in the Gottsche Herbarium which is part of the Stephani Herbarium at Geneva. Stephani also had available a specimen collected in Nelson by Kirk which previously had been regarded as a male plant of F. australis Mitt, for the label reads “Foss. gigantea St. n. sp., sub F. australis Mitt. O” These specimens are accompanied by annotated drawings of the leaf, spore and two types of elaters - a narrow bispiral one and a shorter, wider trispiral one. The spore is said to be densely verrucate, often subpapillate and of diameter 46 μm.
An examination of the specimens and drawings showed that they correspond with F. australis except in the matter of the size and marking of the spore; the name F. gigantea in my opinion is a synonym of F. australis. It seems likely that Stephani may not have had the correct spores but this cannot be checked, as there are no spores with the specimens and no scale with his drawing.
This species was named by Stephani (1900) from male plants collected in New Zealand by Colenso, but even Stephani regarded the identification as uncertain. There is inadequate information for supporting the retention of this species of Fossombronia.
This species has been listed for New Zealand by Gottsche, Lindenberg and Nees (1844-7), Mitten (1855), Stephani (1900) and Hamlin (1972). The type was collected by Drummond at Swan River, Australia (Bonner, 1965). A detailed treatment of the species accompanied by illustrations has been provided recently by Scott (1985). He gave the distribution as Australia and South Africa. No New Zealand plants have been found to correspond with the predominantly Australian F. intestinalis.
A Latin description of this species was published by Herzog (1935). It was based on a specimen, H 346, collected on 21:12:1930 by F. reticulata, although Herzog reported the spore size as somewhat less (22-28 μm). It is concluded that F. microspora is a synonym of F. reticulata Steph.
Colenso (1885) described a new species Noteroclada perpusilla from plants
Fig 6. Left: Distal view of the spore of F. pusilla. Scanning electron micrograph by D.H. Hopcroft and R. Bennett from the same capsule as Fig. 5. Right: Distal view of spore of F. perpusilla. Reproduced by permission of the Stephani Herbarium. Geneva. Scale bars = 10μm.Fossombronia.
The isotype used by Stephani and labelled “New Zealand, Colenso” was examined together with scanning electron micrographs of the spores, one of which is reproduced here (Fig. 6). It is most likely that the original plants are represented also by the packet, Colenso 6498, in the Herbarium of the National Museum of New Zealand (WELT) and labelled as collected at Scinde Island, Napier. Since the specimens correspond with F. pusilla, the name F. perpusilla considered to be a synonym.
Since this paper was submitted there has been an opportunity to examine the sheet of F. australis at the British Museum. It contains 6 smaller sheets of specimens. Three of these comprise male plants collected by Moseley from Heard Island; they were labelled as type material of F. australis Mitt. by B.M. Thiers on July 13, 1982. The other three were collected by E.
Specimens labelled F. australis in the Stephani Herbarium at Geneva were also examined. There were two from Kerguelen Island, collected by Eaton, but none from Heard Island. They were accompanied by a copy of Mitten's drawing of a pseudo-perianth, and of spore mother cells containing spores, with a comment on the latter by Stephani “These are from a fungus”.
Since the name F. australis was first given to the Heard Island plants, a new name must be found for the ones from Kerguelen Island. They appear to correspond
F. naumanni Schiffn. which was named by Schiffner in 1889 from material collected by Naumann on Kerguelen Island (Bonner, 1965). A more recent description based on Australian plants and accompanied by illustrations is given by Scott (1985). The correct name for the New Zealand plants referred to as F. australis in the present paper would then be F. naumannii. The known distribution is Kerguelen Island, Macquarie Island, Australia and New Zealand. Scott (1985) gave no details regarding antheridia. He described a different type of elater from that occurring in New Zealand material but, since capsules are rarely found, it has not been possible to determine how widespread or significant this might be.
The writer is indebted to the curators of the herbaria at the Stephani Herbarium Geneva, the Senckenberg Naturmuseum Frankfurt, the State University Utrecht, the New York Botanical Garden, the British Museum. Botany Division Christ-church and National Museum of New Zealand, Wellington, for the opportunity to study herbarium specimens; to D. Havell, H. Wilson and C. Meurk for providing fresh material and to the Assistant City Engineer (Works) for information regarding the spray programmes carried out by the Upper Hutt City Council on Akatarawa Road.
The Liverworts of New Zealand. University of Otago Press, Dunedin.
Index hepaticarum 5. J. Cramer, Weinheim.
Transactions of the New Zealand Institute 17: 237-263.
Hepaticae of North America 6: 151-161. University of Washington. Seattle.
Synopsis Hepaticarum. Meissner, Hamburg.
Acta Botanica Fennica 121: 1-62.
Records of the Dominion Museum 7: 243-366.
Transactions of the Royal Society of New Zealand 65: 350-356.
FossombroniaRaddi in Japan.
Journal Hattori Botanical Laboratory 37: 293-297.
Atlas Nederlandse Levermossen. Koninklijke Nederlandse Natuurhistorische Vereiniging.
Species Plantarum. Holmiae.
The Botany of the Antarctic Voyage of H.M. Discovery ships Erebus and Terror. II Flora Novae Zelandiae Part 2. Flowerless Plants. Reeve. London.
Journal of the Linnean Society of London (Botany) 15: 59-73.
Journal of the Linnean Society of London (Botany) 15: 193-197.
Philosophical Transactions of the Royal Society of London 168: 187-196.
Kryptogamen-Flora 6, Leipzig.
FossombroniaRaddi.
Journal of Bryology 7: 243-252.
The Hepaticae and Anthocerotae of North America. Columbia University Press, New York.
Southern Australian Liverworts. Australian Government Publishing Service, Canberra.
Hedwigia 33: 9 Stephani. F. 1900:
Species hepaticarum 1: 384.
119 Creswick Terrace, Wellington.
Abstract
The prey is examined of three species of web-building spiders which are commonly found in the open country, bush fringe and urban areas of Wellington, New Zealand. The species are: Achaearanea veruculata, F. Theridiidae (the small cobweb spider): Artaneus pustulosus, F. Araneidae (the garden orb web spider); and Ixeuticus martius. F. Dictynidae (the black house spider). Prey is compared numerically and from a biomass point-of-view. Web examinations revealed that A. veruculata captures a wider range of prey than either of the other two species. A significant amount of its food comes from predation on other spiders. A. pustulosus feeds mainly on Diptera (62% of its prey) while I. martius also feeds mainly on Diptera (57% of its prey). These two species are regarded as competing strongly for food, with a lesser degree of competition occurring between either of the two and A. veruculata. Young spiders of all three species fed mainly on prey which was smaller than that captured by the adult spiders, but it was concluded that some food niche shift occurs in the life cycle of the three species. A comparison of clutch sizes and clutch production showed that A. pustulosus has a far higher natality rate than either of the other species. A. pustulosus also suffers from many more sources of mortality than the other two species.
Keywords:Achaearanea veruculata, Araneus pustulosus, Araneidae, competition, Dictynidae, food selection. Ixeuticus martius, mortality, spiderling.
Introduction
This study was conducted to see if any marked overlap in prey occurred between three species of web-building spiders which commonly occupy the same part of the habitat in urban Wellington, and the fringe of nearby bush areas.
The three species are:
Achaearanea veruculata (Theridiidae) - the small cobweb spider. (Fig. 1). This species, by far the smallest of the three, reaches to about 5mm body length. It is fawn to brown in colour and builds a cobweb of untidy threads in crevices of rocks or trees, also on dwellings, shrubs and fences. Its captured prey is wrapped up with a technique of throwing threads around the animals. This technique is shared with other theridiids such as Steatoda and Latrodectus (the katipo).
Araneus pustulosus (Araneidae) - the garden orb web spider. (Fig. 2). This species grows to 15mm body length, and shows a wide colour variation from cream through brown and green to near-black. It builds an orb web of radiating threads with a spiral thread laid on to the radials. The web may be found on bushes, dwellings, fences and on rock faces where projecting surfaces are available. Prey are wrapped up by rolling with the legs while silk is dispensed from the spinnerets.
Ixeuticus martius (Dictynidae) - the black house spider. (Fig. 3). This species grows to 15mm body length and while brownish when young, darkens with age until parts of the body are black. Other parts carry whitish hairs giving this species a greyish appearance. The web is a series of struts on which a zig-zag pattern is woven, but as the web ages it becomes disordered and the strut and zig-zag pattern is often hard to see. Prey are grabbed and dragged to the spider's retreat to be dealt with there.
Ixeuticus is the only one of these three species to construct a definite retreat of silken thread. A. pustulosus lies exposed on a surface while A. veruculata hides in a crevice when possible.
Fig. 1. Achaearanea veruculata shown in a typical posture. The dorsal surface faces to the ground. Fig. 2. Araneus pustulosus shown at the centre of its orb web. The spider normally faces head towards the ground. An insect prey can be seen above the spider, well wrapped in silk. Fig 3. Ixeuticus martius in a typical posture at night, waiting for prey to contact the web.
Four localities around Wellington were chosen for study. These were:
The fringe of Otari Reserve in Wilton, where The south-eastern slopes of the Tinakori Hills adjacent to Wadestown. Here A crib-wall garden on a path running between Hill Street and Hawkestone Street in Thorndon. This faces north west and insects probably arrive here from Tinakori Hills, and further north from Otari and the farmland beyond. The spider webs here are mainly found on the ornamental plants of the crib-wall. These are the prostrate rosemary A garden and roadside reserve at the author's home in suburban Northland. Here the exposure is to the north so insects could be carried from the farmland and bush remnants around Johnston Hill and further out. All three species were present here with webs on flowers, shrubs, house, fences, and rocky bank at the roadside.A veruculata and A. pustulosus were present in large numbers, with I. martius less common. This locality is exposed to both of Wellington's main winds - north-westerlies and southerlies. Insects are carried from farmland to the north and west, and from within the bush, which is mixed broadleaf with some podocarps. From the south insects will be carried from the slopes of Tinakori Hills and the urban areas.A. veruculata and A. pustulosus were present on rock faces and trees, with some I. martius as well. This location is adjacent to macrocarpa, pine and
coprosma. Insects are carried here from farmland and the bush reserve at Otari.(Rosemarinus officinalis var. prostratus) and a yellow flowering succulent, Sedum sp. This urban area is rich in all three species of spider.
Method
A preliminary study provided the outline for a web-collecting programme in which 100 prey-containing webs were examined for each species in each of the four seasons. Thus a total of 400 webs were found for each species, accumulated at the rate of 10 per week spread over the four locations.
The webs of the species studied do not always contain recognisable prey remains. It was found in the preliminary survey that for every usable web, between five and 10 webs need to be examined. This gave a figure of between 6,000 and 12,000 web examinations over the year in order to find the 1200 prey-containing webs required for the three species comparison. Only prey which were actively being fed on, or had recently been fed on by the spiders were counted in the study. Familiarisation with the collection sites and positions of webs ensured that double counting of remains was avoided. This is an important point because some prey (e.g. beetles) can persist in webs for many weeks after the spider has fed on them.
The prey remains were identified to family level where possible and these data used to draw up results (Tables 1-7).
Where possible a measurement was made to the body length of spiders found with prey in order to relate the prey captured to the maturity of the spider.
Spiders were placed into one of the folowing groups for this intraspecific comparison:
-
Spiderlings - those spiders in the first 1-2 months of independent life.
-
Immature spiders - those which had been in their own webs for at least two months but which had not yet reached sexual maturity.
-
Mature spiders - those which had reached sexual maturity. Body length measurement of each species in relation to maturity is as follows:
The dividing line between spiderlings and immature spiders is somewhat arbitrary, but that between immatures and matures was based on the body length of females found with egg sacs. The results of the survey are presented in Tables 1-7.
Prey Comparison Between Species
In this species, Diptera (35.4%) were numerically the largest prey group, but they were not nearly as significant as they were to the other two species. The Hymenoptera (18.2%) were the next most significant prey for A. veruculata. Here ants (N = 74) were the single largest family. The web of this species seems well suited to the capture of walking insects and this would explain partly the high capture level of ants. Another feature of A. veruculata's feeding is its predation on spiders, particularly on I. martius. Close observations of these two species on the side of the author's house showed that the captures of I. martius were probably related to members of this species changing their web sites. The captured spiders in many instances having moved 30cm or more from their known web site. A. veruculata quickly and readily wraps up other spiders with the silk-throwing technique mentioned earlier. The other unusual feature of this species prey is its feeding on slaters (Isopoda), millipedes (Diplopoda) and harvestmen (Opiliones), all prey groups which are either absent or found in minimal numbers in the webs of A. pustulosus and I. martius.
Table 2 shows some niche differentiation between the spiderlings and the mature spiders, with smaller prey such as psyllids and phorids being important to spiderlings, while mature spiders utilise other spiders as the most numerous prey item. There is thus a shift towards predation on other spiders as A. veruculata matures. The importance of very large prey such as cicadas is discussed below. Seasonal prey differences were not especially marked in this species. Ants are most significant in summer (N = 28); craneflies (Tipulidae) in autumn (N = 21); and through the winter fungus gnats (Mycetophylidae) (N = 30) are an important food source.
Diptera (62%) were again by far the most numerous prey group, with Mycetophilidae (N = 351) being the most common item. Of the rest of the prey groups, only the Hemiptera (16%) and the Hymenoptera (14%) exceeded double figures as percent of prey caught. The orb web. which is strung in the flight path of insects, appears well suited to capturing Diptera. Because of its location in the habitat, it is less well suited for the capture of other prey groups which spend either all or most of their time walking. This was well illustrated by the capture of ants which were all winged forms in the orb-webs of A. pustulosus but walking ants in the cob-web traps of A. veruculata. A. pustulosus is definitely more restricted in its diet than A. veruculata, as shown in the relative paucity of items in the “other” prey category.
There is a clear niche shift in prey taken at different stages of development of A. pustulosus. The spiderlings take a variety of small prey such as psyllids, aphids,
Apis mellifera) with an occasional bumble bee (Bombus sp.) being found. Bees are a problem prey item for A. pustulosus; they yield a large amount of food for the spider and so are well worth capturing, but the hazards of being stung are always present and a number of adult spiders were observed misjudging the wrapping-up of either honey bees or bumble bees - and were seen to be stung. In all cases the spider died as a result (see Table 12).
There were some seasonal differences apparent in this species, but these tended to be obscured by the predominance of mycetophylids in the prey count. In winter this group assumed even greater significance. 169 captures being found. In summer psyllids were numerically important but would be significant only for the small spiders. In autumn aphids and ants (N = 34 and 47 respectively) are important but mainly for smaller spiders.
Like A. pustulosus, I. martius relies heavily on Diptera for its food intake. This order made up 57% of the total prey caught. The difference between these two spiders is the wider spread among the families within the Diptera by I. martius. The Mycetophylidae are not the dominant item as in A. pustulosus. Here Muscidae. Acalyptrata and Tipulidae are all very important with Calliphoridae and Stratiomyiidae being significant too. As in A. pustulosus, flying ants were caught and formed a useful addition to the diet in summer and autumn. Cicadas form an important item in summer (N = 15) and because of their large size must be even more important than their numbers alone suggest. In winter prey are scarce and flies such as craneflies, fungus gnats, muscids and blowflies are particularly important for the continued growth and maturation of I. martius. As the spider grows, smaller prey, like psyllids and ants which are present in significant numbers in the food of the spiderlings, become unimportant for mature spiders. The larger flies such as tipulids and stratiomyiids along with the cicadas are very important in the diet of the mature spiders.
Prey Size
The numerical data given in Tables 1-7 give no indication of the volume of food the prey contains, or its biomass. It is clear that a small fungus gnat is not as valuable a catch as a honey bee or a cicada. An attempt was made to relate the prey groups to one another in terms of food volume. The standard used was a very common prey item: a mycetophylid fly of 5mm body length. It was estimated that with a body diameter of 1.5mm, such a fly would contain approximately 8.8mm3 volume of food. The food volumes of other prey were estimated in the same manner and were then converted to “mycetophilid equivalents”. For example, a honey bee with a volume of 150 mm3 is equal to 15 mycetophylid units. A list of mycetophylid equivalents follows in Table 8.
Comparisons between the 12 major prey items for each spider species were made by multiplying the number of prey captured by the “mycetophilid equivalent”, (e.g. cicadas for A. veruculata: 60 × 13 = 780). These figures are presented in Table 9. Here the following prey items become much more significant than they were on a numberical count:
A. veruculata - cicadas, bees, tipulids and slaters
A. pustulosus - blowflies, bees and tipulids
I. martius - cicadas, bees and soldier flies
Cicadas could be particularly important for females of A. veruculata and I. martius. This is because egg sac production requires a substantial food input and without the addition of cicadas to the diet in summer and autumn it is probable that this activity would be curtailed in these two species.
Interspecific Predation
This study revealed high levels of interspecific predation by the small A. veruculata on I. martius and to a lesser degree on A. pustulosus (Table 10). Predation on other spiders by I. martius and A. pustulosus was less evident. The captures occurred in two ways. Firstly when the webs of two spiders were closely adjacent to one another and contact with the web of one was made by the other.
Secondly when spiders wandered from an older web site. I. martius was particularly prone to capture by A. veruculata in the second of these circumstances.
Clutch Size and Clutch Production (Natality)
Observations on egg sac production were made during the prey study. These showed that A. pustulosus was by far the most prolific species, in some individuals producing up to five sacs per year with more than 800 eggs per sac being counted. A. veruculata and I martius had a lower natality rate, producing considerably fewer eggs per sac than A. pustulosus (see Table 11). In I. martius the spiderlings appear 6 weeks after the early clutches are produced in August. Dispersal takes place any time from early spring in this species. A similar pattern is seen in A. veruculata but A. pustulosus egg sacs and spiderlings are not seen for almost a month later than those of the other two species in Wellington.
Mortality
The prey study provides an opportunity to observe and record causes of mortality in known populations of the three spider species (Table 12). Although not a quantitative investigation, these data suggest that A. pustulosus appeared to suffer the highest mortality. Perhaps this is not surprising in view of its exposed web, without a protective retreat, and its much higher natality than the other two species. The spider has a bulky shape which makes it an easy target for bird and wasp attack. It also suffers more storm damage than the other spiders. I. martius is by far the best protected of these three spiders, with its woven silk retreat, but is also the most difficult to observe.
Conclusions
These three spider species often live in the same habitat and could thus compete for web sites. Inter-specific predation, particularly on I. martius, may well be an indication of this. The study has revealed considerable overlap between the spiders in their food items. In particular between Araneus pustulosus and Ixeuticus martius, both of which depend so heavily on the same types of Diptera. Achaearanea veruculata feeds on the widest range of prey diversity of the three species, partly due to its choice of web site and partly to its prey-capturing behaviour. A. pustulosus had the distinction of capturing prey at about double the rate of the other two species. Although no attempt was made to determine growth rates, it appears from the natality and mortality data gathered in this study that this species has a
Acknowledgements
My thanks to Mr R. Ordish, entomologist. National Museum, Wellington, for his help in identifying the prey items found in this study, and to
References
Department of Biological Sciences, University of Waikato, Private Bag, Hamilton, New Zealand
Key words: Reptilia, Sphenodon, tuatara, feeding, nocturnal, behaviour, vision, infra-red-radiation.
Observations and Discussion
We have been keeping three young tuatara (Sphenodon punctatus) since May 1987 in the laboratory under natural light conditions for an investigation of tail regeneration and spinal cord ultrastructure (Alibardi & Meyer-Rochow. in prep.). The animals have been developing very well since they hatched in April 1987 and have been putting on weight at the rate of approx. 0.9 g/month on a mixed diet of slaters (mostly Oniscus sp.). amphipods (Talitrus spp.), mealworms (Tenebrio molitor), beetles (Chaerodes sp.), and flies (Musca sp.).
Because some reptiles e.g. crotalid snakes (Hartline et al. 1978) have infra-red perception and use it to locate prey in the dark, I tested whether tuatara react in any way to infra-red radiation and observed how they behave in an environment that is totally dark to the human eye. Conditions such as these can occur in the wild, e.g. deep underground burrows, caves etc.
The observations were carried out in a photographic dark-room, equipped with Kodak Wratten 6B safety lights, using a “Find-R-Scope” infra-red emitter/viewer (Lindstrom and Meyer-Rochow 1987).
Two test tuatara were not fed for three days, after which the cage containing the animals was placed in the photographic dark-room at 11.00 h. From then on all safety lights were switched off and it was totally dark. Two hours later the first test of the tuatara's reaction to the presentation of a mealworm under infra-red radiation was carried out. There was not the slightest reaction of either animal to either the beam of the infra-red light source striking them or the rapidly wriggling mealworm only 2cm in front of them. As the amount of visual pigment could possibly have been rather low at that time of day (prolonged dark adaptation results in greatly improved absolute sensitivity (Kleinschmidt & Dowling, 1975), another presentation was made at approx. 19.00 h. Once again there was no reaction.
These observations were repeated on the second and the third day of darkness - always with the same result - no reaction to the beam of the infra-red light and no reaction to the mealworm. The sound made by the mealworm when crawling in amongst dry leaves (audible to a human and no different from an illuminated worm), or its smell, were ineffective and there was no reaction to the approach of a human hand. When photographic safety lights were used instead of the infra-red light, the tuatara still did not react to the mealworm. When the cage was removed from the dark-room and exposed to ordinary daylight again, the two tuatara immediately seized and swallowed the mealworms.
We conclude from these observations that young tuatara, in all likelihood, do not use acoustic or olfactory cues, but react purely visually to potential prey. A tuatara underground or in a dark cave, therefore, is not likely to take up food even in the presence of some. The absence of any reaction whatsoever to infra-red light agrees with observations on a single, male adult tuatara made in 1973 by Wojtusiak, but their seemingly low sensitivity to light of longer wave-lengths comes as a bit of a surprise, for tuatara are regarded as nocturnal and there is,
Geoclemys reevesii (Ohtsuka, 1985) show very good red sensitivity.
Fig. 1.(from Lindstrom and Meyer-Rochow 1987) Filter characteristics as supplied by the manufacturer: the solid line and the top abscissa refer to Kodak Wratten filter 87 while the broken line and bottom abscissa describe the transmittance of the O'Hara RT-2 filter used in the “Find-R-Scope” infra-red viewer/emitter.
To some extent knowledge of the photoreceptor cell types in the retina of the tuatara could help to resolve the problem as to whether the eye of the tuatara is (a) primarily a rod-dominated receptor adapted to function as a black and white detector in dim light, or (b) a cone-dominated colour receptor originally for use in brighter light. On the basis of what is known about the tuatara retina, however, no consensus even on the cell types can be reached. Walls (1942) for example, calls a particular group of cells in the tuatara retina “rods”; Vilter (1951) calls the same cells “cones”, and Underwood (1970) after “careful scrutiny of Walls’ excellently fixed material” distinguishes major and minor single cells, double cells, and dwarf cones. The only way to solve this microanatomical riddle is by the use of an electron mcroscope, for then cones and rods can be identified without ambiguity.
Acknowledgements
The support of the New Zealand UGC for making funds available towards the purchase of equipment is gratefully acknowledged. Thanks are also given to Dr M.
References
Sphenodon punctatus. In prep.
KassL. and
LoopM.S. 1978: Merging of modalities in the optic tectum: infrared and visual integration in rattlesnakes.
Science 199: 1225-1229.
Journal of General Physiology 66: 617-648.
Light as an Ecological Factor, Blackwell Science Publications, Oxford.
Mysis relicta? Biochemical and Biophysical Research Communications. 147: 747-752.
Geoclemys reevesii. Journal of Comparative Neurology. 237: 145-154.
Biology of the Reptiliavolume 2. Academic Press, London.
(Sphenodon punctatus). Comptes Rendus des Seances de la Societe de Biologie et de ses Filiales 145: 20-23.
Cranbook Institute of Science Bulletin. 19: 1-785.
Tuatara 20: 97-109.
Department of Zoology and Museum of Vertebrate Zoology, University of California, Berkeley, California, U.S.A. 94720
Present address: Department of Biological Sciences, The University of Calgary, 2500 University Drive, N.W., Calgary, Alberta, Canada T2N 1N4.
Abstract
The terrestrial reptilian fauna of New Caledonia consits almost entirely of lizards of the families Gekkonidae and Scincidae. Despite low familial diversity, species and generic diversity are high and both the geckos and skinks are primarily endemic. Patterns of high herpetofaunal similarity that typify the central and eastern Pacific are generally absent in the southwest Pacific. Despite phylogenetic ties to the faunas of Australia and New Zealand and relatively small distances between New Caledonia and components of the Outer Melanesian Arc, species level similarities between New Caledonia and other island groups is extremely low. Misinterpretation of the systematics and basic biology of both geckos and skinks has led to prevailing, erroneous views that these reptiles are of little use in biogeographic analysis. Implications of this invalid conclusion, as illustrated by a recent biogeographic analysis of the western Pacific, are exposed and criticized.
Key words: New Caledonia, Pacific biogeography, Gekkonidae, Scincidae, systematics, vagility, herpetofauna.
Introduction
New Caledonia is a French territory located about 1500 km off the coast of Queensland. Along with the Loyalty Islands, it lies between the Coral Sea and the Vanuatu Trench. The islands have had a long geological history and occupy an area of over 19,00 km2 at the southern limits of the tropics.
Living representatives of two families of reptiles, the Gekkonidae and the Scincidae, are native to New Caledonia. A third family, the Typhlopidae, is represented by the introduced parthenogenetic Ramphotyphlops braminus (Bauer, 1987). In addition, an archaic mesosuchian crocodile (Buffetaut, 1983) is known from the Pleistocene karstic deposits of the Baie de Kanumera on the Isle of Pines, and meiolaniid turtles have been recorded from Nepoui on the New Caledonian mainland (1700 ± 70 ybp), from Tiga in the Loyalty group (Gaffney et al., 1984), and from Walpole Island to the southeast of New Caledonia. Unidentified varanid remains also come from the Nepoui site (Gaffney et al., 1984).
This herpetofauna has been considered improverished by some workers (e.g. Hedley, 1899; Buffetaut, 1983). Indeed, the vertebrate fauna of New Caledonia, with its lack of amphibians and non-volant mammals, has generally been regarded as rather uninteresting by zoologists (see Balgooy, 1969). Primary freshwater fish are lacking, with the exception of Nesogalaxias neocaledonicus, a member of a lineage of generally salt-tolerant fishes. The avifauna has also been sterotyped as unremarkable, with few endemic genera and only one endemic family (Diamond, 1984). Berlioz (1962), however, noted that only 26% of the avifauna was composed of passerines, in contrast to 50% for the world as a whole. Only relatively nonvagile invertebrate groups, such as land snails (which show 99% endemism on New Caledonia) (Tillier and Clarke, 1983) have generally been regarded as interesting from a broad zoological standpoint. This is in stark contrast to the flora of New Caledonia, which is characterized by high levels of endemism, especially in
et al., 1984), and has been considered to have “good claim to be considered the most remarkable in the world” (Good, 1974).
The Herpetofauna of New Caledonia in Relation to that of other Regions of the Pacific
The number of reptile species in New Caledonia (38 terrestrial species) is low in absolute terms, but high relative to other areas of Oceania. Only New Guinea (total terrestrial herpetofauna 270 species), the Solomon Islands (87 species) and New Zealand (42 species) have more. Despite a general lack of interest among zoologists, a few workers (e.g. Bavay, 1869; Roux, 1913) have noted the high level of endemism among New Caledonian reptiles. The latter demonstrated the dissimilarity of the faunas of New Caledonia and neighbouring Vanuatu and suggested the Loyalty Islands as an area where elements of these two disparate faunas meet.
The diversity and uniqueness of the New Caledonian herpetofauna can be appreciated by referring to a graphic representation of herpetofaunal similarity among island groups of the Pacific as a whole. The location of each group and the similarity of its terrestrial herpetofauna to that of its neighbours is illustrated in Figures 1-3. Similarity (at the species level) has been estimated using the formula: -
Fig. 1Herpetofaunal similarity coefficients for island groups in the South-central and Southeast Pacific (degrees in south latitude and west longitude). Abbreviations for Figs. 1-3 as follows:AI - Austral IslandsCA - Caroline IslandsCI - Cook IslandsEI - Easter IslandFI - FijiGM - Gambier ArchipelagoHI - Hawaiian IslandsKI - KirbatiKP - Kapingamarangi AtollLH - Lord Howe IslandLI - Line IslandsLO - Loyalty IslandsMA - Marshall IslandsMI - Marquesas IslandsMR - Marianas islands (incl. Guam)NA - NauruNC - New CaledoniaNF - Norfolk IslandNG - New GuineaNI - NiueNZ - New ZealandOC - Ocean IslandPI - Pitcairn IslandPL - PalauRB - Rennell and Bellona IslandsSA - SamoaSC - Santa Cruz and Duff IslandsSI - Society IslandsSL - Solomon IslandsTA - Tuamotu ArchipelagoTK - Tokelau IslandsTO - TongaTU - TuvaluVA - VanuatuWF - Wallis and Futuna IslandsFig. 2Herpetofaunal similarity coefficients for island groups in the northwestern tropical Pacific (degrees in north latitude and east longtitude). For abbreviations see Fig. 1.Fig. 3Herpetofaunal similarity coefficients for island groups in the Southwest Pacific (degrees in south latitude and east longitude). For abbreviations see Fig. 1.
Species lists (Bauer, 1986; W.C. Brown, MS) used as a basis for this analysis were prepared from museum data and an extensive literature review (see Bauer, 1986: 845-867). The similarity coefficient is heavily weighted by the absolute number of taxa occuring in the areas (thus Pitcairn Island, with only one species can have at most a 20% similarity with an island supporting nine species). In general, species diversity is low on the islands to the east of Fiji and decreases further to the east of Samoa. Likewise, areas to the north of Vanuatu and Samoa, and east of the Solomon Islands are also depauperate. Hawaii is anomalous with its relatively large lizard fauna, but this probably reflects the influence of Polynesian and European man (Stejneger, 1899; Hunsaker and Breese, 1967; Oliver and Shaw, 1953; McKeown, 1978). Small islands, no matter where they occur, are also poor in species diversity. These include Nauru, Ocean Island, the Line Islands (data only from Vostok and Caroline Atolls), Wallis and Futuna, Niue, Pitcairn Island and Easter Island. The last two islands also suffer from their extreme isolation. Despite this drawback, and the fact that it does not take into account the relatedness of congeners, the coefficient does give an overview of patterns of similarity between areas. Thus high percentages suggest a uniform fauna, both in size and composition, and very low percentages between islands of similar size suggest extreme faunal dissimilarity. Similarly, it may be extrapolated that islands
Figure 1 shows faunal similarities in the southeast Pacific. The relative homogeneity in the eastern Pacific is indicated by coefficients of 71 to 92% among all groups of Polynesian islands excluding Easter Island and Pitcairn. The species present are chiefly pan-Pacific geckos and skinks and, as with Hawaii, many may have arrived through the agencies of man (Garman, 1908; Ineich. 1982). This high degree of relatedness generally persists as far west as Samoa and the Tokelaus and then gives way to a more complex pattern of relationships.
Reasonably high similarities (39-67%) link the islands of Micronesia (Fig. 2). Palau, with a fauna of 28 species shows the influence of the Philippines (Brown, 1956) and this continues in attenuated form throughout the region. None of the northern islands shows a high similarity to the Tokelaus, although a similar coefficient characterized their relationship to the Marshall Islands to the north. The relatively isolated and small Kapingamarangi Atoll shares a surprisingly high coefficient (indicative of its relatively large fauna) when compared with the Caroline Islands as a whole. Kapingamarangi also possesses an endemic species of the gecko Perochirus.
In the western and west central south Pacific (Fig. 3), several interesting trends are seen. All of the adjacent island groups to the east of the South Fiji Basin (except Wallis and Futuna) share herpetofaunal similarities of about 40% with Fiji, Tonga, Samoa and the Tokelau Islands have largely similar faunas and also have similarities to the Cook Islands and eastern Polynesia in general. The components of the Outer Melanesian Arc - the Solomons, Santa Cruz and Duff Islands, Rennell and Bellona. Vanuatu and Fiji share a similar herepetofauna, although there is a general diminution of species number and diversity with distance from the Solomons. The Santa Cruz Islands, Rennell and Bellona, and Vanuatu all share about 30% of their herpetofaunas with the Solomons. The similarity coefficient for the Fiji-Solomons comparison (not shown) is 19%. Even this figure is fairly high given the large geographical distance separating the areas and the discrepancy in faunal size. There is an interesting relationship among the faunas of Vanuatu and Fiji in that the former has fewer species than the latter, despite its proximity to the supposed source (the Solomons) (Bauer, submitted). Further, Vanuatu lacks the ranid frog Platymantis present in the Solomons and in Fiji. A possible geological explanation for this anomaly is that, prior to the Miocene, Vanuatu lay north of Fiji and Tonga (Chase, 1971), more distant from the Solomons than either of the latter. On the whole the Outer Arc is typified by the presence of the boid Candoia and many species of the scincid Emoia, as well as a variety of generally widespread gekkonine geckos.
New Caledonia, on the other hand, is almost as distinct as New Zealand at the specific level. It shares only a 4% coefficient with the Solomons and 10% with Vanuatu, although the latter is only little more than 250 km distant. The Loyalty Islands, as Roux (1913) noted, are intermediate in character between New Caledonia and the Outer Arc. They share similarity coefficients of 41% with New Caledonia and 25% with Vanuatu. Lord Howe Island and Norfolk Island have identical faunas of two species, neither of which occurs elsewhere.
The low similarity of the New Caledonian herpetofauna to that of the Outer Arc, or in comparison with inter-Outer Arc elements, clearly suggests distinctness
Leiolopisma atropunctatus is the only New Caledonian species that seems to have reached Vanuatu, and it is likely that this dispersal occurred via the Loyalty Islands in the Quaternary. That some New Caledonian forms (e.g. Bavayia and Phoboscincus) occur in the Loyalty Islands indicates that dispersal can take place, but either most New Caledonian forms have low vagility or the water gap prior to the rotation of Vanuatu and the emergence of the Loyalty Islands was too great a barrier to dispersal for this to occur.
A Genus is a Genus, A Gecko is a Gecko, and other Fallacies
Although the geckos and skinks of New Caledonia are primarily endemic, there is a general consensus that these animals are not particularly useful in terms of assessing biogeographical hypotheses. This assessment appears to stem from two misconceptions. The first is a problem that pervades biogeography and many other branches of biology and that stems from inadequate systematic analysis of the groups involved. While the geckos of New Caledonia have usually been placed in their own genera, the skinks have not, and it is the genus which is usually taken as the unit of analysis in biogeography. Indeed, because of the system of binomial nomenclature, the genus assumes more reality in the minds of many biologists than it has in nature. It is thus incumbent upon systematists to apply generic names in the most informative manner possible, maintaining as far as is possible phylogenetic information in the nomenclature (Greer, 1979). It must be remembered that for the physiologist or behaviorist working on representative animals in a familial taxon, with no direct access to systematic literature, any two genera will probably be taken as being as disparate as any other two, a phenomenon that can, and does, lead to incorrect generalizations and false predictions. While this situation should not apply to biogeographers, (see Nelson and Platnick, 1981), sadly it often does.
In the case of the New Caledonian and New Zealand skinks, the application of the generic name Lygosoma until the middle of this century (Greer, 1977) obscured true relationships and suggested that much of the world was populated by a single genus which must have spread rapidly and recently. The high number of Lygosoma species in the Old World tropics reinforced or helped form Darlington's (1948, 1957) views of this area as the cradle of most reptilian groups. In New Zealand, additional problems resulted from the use of the generic name Sphenomorphus for certain scincids. As currently recognized (Greer, 1974), this genus occurs in New Guinea, the Solomon Islands, Australia and parts of southeast Asia. Again, the association of New Zealand forms with these species suggested affinities similar to those of Outer Arc birds and downplayed the uniqueness of the fauna.
Currently, the skinks of New Zealand are placed into two genera, Leiolopisma and Cyclodina, and, until recently, those of New Caledonia were placed into five, Leiolopisma, Anotis (a nomenclatoral and systematic tangle in itself), Cryptoblepharus, Eugongylus (recognized by Greer (1974) to be a paraphyletic) and Phoboscincus (regarded by Bohme (1976) as a derived Eugongylus). Leiolopisma accounts for most of these species. This genus is distributed in Australia, New Caledonia, New Zealand, Fiji and the Mascarene Islands (Leiolopisma lichengera of
Cyclodina). It is definitely paraphyletic (Greer, 1980; Zug, 1985). If one were ignorant of the systematic problems with the genus, its distribution might suggest an early Gondwanan origin for the group and subsequent vicariant splitting of lineages. However, current thought is that the group has achieved its present distribution at least in part by means of dispersal. This, in turn, leads us back to the problem of Lygosoma. However, Sadlier (1987) has divided the New Caledonian skinks into presumably monophyletic groupings which, by virtue of the binomial, erases nomenclatural evidence of broader relationships but increases the apparent level of endemicity in New Caledonia by creating taxa with generic names different from those found elsewhere in the southwest Pacific. Similarly, the reinstatement of Cyclodina by Hardy (1977) for certain New Zealand skinks formerly assigned to Leiolopisma successfully increased the apparent wealth of the herpetofauna, but still left Leiolopisma paraphyletic.
The second factor leading to a de-emphasis of the uniqueness of the New Caledonian (and New Zealand) herpetofauna, and to the misinterpretation of historical biogeography, is the persistent myth that geckos, and to a lesser extent, skinks, are animals adapted to disperal. A glance through island species lists shows that skinks and geckos are the only reptiles present on many remote islands, and that on islands where other groups also occur, geckos and skinks are the most speciose. Thus, as a legacy of the school of dispersalism, these animals have been generally considered highly vagile.
The vagility associated with geckos, in particular, has traditionally been predicted on the view that geckos and their eggs are particularly well suited to transoceanic travel and that they are likely to be transported (as evidenced by their commensalism with humans and subsequent accidental transport). Indeed, it has been demonstrated that geckos eggs are relatively more resistant to sea-water exposure than are the eggs of other reptiles, including skinks (Brown and Alcala, 1957; Dunson, 1982; Dunson and Bramham, 1981; Gardner, 1985) and eggs have been recovered from driftwood (Kew, 1983). This “transportability” and gekkonid commensalism with man is probably responsible for the huge ranges of such forms as Lepidodactylus lugubris (a species also possessing another quality condusive to dispersability - parthenogensis (Cuellar, 1977)) and Hemidactylus frenatus, these being found today on almost every island in the tropical Pacific. In fact, the range of the latter species is known to have increased as a result of the transport of men and equipment in the Pacific Theatre of World War II. Stejneger (1899), Oliver and Shaw (1953), Hunsaker and Breese (1967) and McKeown (1980) all agreed that most if not all of the Hawaiian herpetofauna could be accounted for by human activities. Ineich (1982) considered Lepidodactylus lugubris, Crytoblepharis boutonii poecilopleurus and Emoia cyanura as the only species likely to have inhabited the Society and neighboring islands in pre-Polynesian times.
These features of dispersability do not, however, extend to all geckos (Pasteur, 1964). In fact, they probably apply to only a small number of species. Species of the gekkonidae subfamily Diplodactylinae, in particular, have low vagility. The calcareous egg-shell that permits gekkonine eggs to withstand exposure to sea water is absent in the Diplodactylinae, which have a leathery shell, typical of most squamates (Werner, 1972). Furthermore, no diplodactylines (with the possible exception of Hoplodactylus chrysosireticus) are commensal with man, although Phyllurus platurus may be associated with homes constructed in areas of suitable rocky habitat.
McCann's (1953) analysis of gekkonid dispersal is flawed in its application of the qualities of vagility to the New Zealand species of carphodactylines. He further suggested
Gymnodactylus, Gonatodes (including Cnemaspis), and Phyllodactylus and thus ran into the nomenclatoral problem mentioned earlier.
A glance at the ranges of the carphodactyline species (see Bauer, 1986; Cogger, 1986; Robb, 1986) shows that, with the exceptions of Bavayia on the Loyalty Islands and Hoplodactylus on the Three Kings and Poor Knights Islands, no species occur on islands that were not connected to the closest mainland during periods of Pleistocene glaciations.
The general view of geckos as highly vagile organisms has become entrenched in the biogeographical literature, and geckos are frequently dismissed as having no utility as biogeographical indicators (e.g. Paulin, 1961). Authors have invariably highlighted the herpetofaunal poverty of New Caledonia and New Zealand by stressing that only geckos and skinks among squamates occur there (Thorne, 1965; Carlquist, 1965, 1974; Diamond, 1984). Undoubtedly, the acceptance of the vagility of the carphodactylines, even in the face of evidence of their ability to disperse, has influenced the writing of those who have continued to accept a Mid Tertiary radiation of the group into Tasmantis despite geological evidence to the contrary (see Bauer, 1986). Thus, our biogeographic explorations depend not only upon a clear understanding of historical geological phenomena, but also a willingness to take the time to perform adequate systematic studies of the groups that occupy the regions in which we are interested. Furthermore, the biological attributes of the taxa of the region of study should be evaluated in this systematic context and not merely be indirectly superimposed from the more generalized conception gleaned from “characterizing” the higher taxa to which they belong. Is a platypus any less of a mammal because it lays eggs?
The Uniqueness of New Caledonia: A Response to Diamond(1984)
Diamond (1984) chose New Caledonia as an example to illustrate his views on speciation in Pacific vertebrates. He regarded many Pacific island biotas as mosaics. In contrast to the fauna of New Guinea, which he regarded as rich and diverse. Diamond stated “from the vertebrate fauna one could not guess that New Caledonia had existed prior to the Pleistocene”. Diamond's goal was to build a case for his hypothesis (Diamond, 1977) that the pattern of diversity of Pacific island faunas is largely a function of the ability of vertebrates to speciate into a radiation in some areas but not in others. This ability, Diamond argued, is related to the minimum size at which islands take on continental characteristics with respect to their faunas.
Diamond's work (1977, 1984) is based primarily on data from birds, and for this group of vertebrates his hypothesis is well supported by patterns of distribution and diversity. However, there is little evidence to suggest that this hypothesis is applicable to all other vertebrates. In particular, Diamond's (1984) support for his theory gleaned from New Caledonian reptiles is based on misconceptions rooted in the fallacies discussed above. Reinterpretation of Diamond's arguments in light of this may or may not seriously weaken this hypothesis as a whole, but they do serve to point out the inherent differences between the study of the biogeography of birds and that of reptiles. They also illustrate the biological uniqueness of the New Caledonian region that has been neglected because of a
Diamond characterized the reptile fauna of New Caledonia as rather depauperate, with only half of the genera endemic, no endemic families and no especially ancient lineages. These statements are either false or do not reflect the intimated poverty of the fauna. In the first case Diamond (1984) accepted nomenclature which does not reflect phylogeny; in the current view of the New Caledonian fauna (Sadlier, 1987) there are, in fact, a large number of endemic genera (while Sadlier's revision was not available to Diamond, the work of Greer [1974] was, and would have provided a suitable basis for analysis). Furthermore, the non-endemic gekkonine genera are represented by single species of wide-ranging forms. The discussion of endemic families belies Diamond's avian bias and is largely irrelevant to the distinctness of the New Caledonian faunas. Reptile families are few in number (20 are represented in Oceania compared with approximately 100 avian families) and are in no biological sense comparable in definition or extent to avian groups of the same nomenclatural rank. The only endemic lizard “family” in Oceania is the Pygopodidae, which is in fact a subgroup to the family Gekko-nidae (Kluge, 1987). In terms of the antiquity of the fauna, Diamond seems not even to have accepted Kluge's (1967a, 1967b) scenario for the group; this implied at least a Mioclene presence of geckos in New Caledonia. More recent work (Bauer, 1986) has indicated that a Paleocene or late Mesozoic presence is more likely.
In arguing for relatively recent dispersal and subsequent radiation to account for certain facets of the New Caledonian biota Diamond (1984) posed the question “where are the frogs, lizards, birds and mammals of Gondowanan origin?” I shall address each group mentioned. Frogs are absent as far as is known, but if present would most likely be leiopelmatids. It is quite possible that frogs, if they had been present in New Caledonia, would not have survived the Eocene ultramafic over-thrusts, because these imposed dramatic changes on aquatic environments and vegetation. The kagu, Rhynchocetos jubatus, represents a monotypic family that may have pre-Oligocene ties to the rail-like birds of New Zealand. Mammals had not arrived in the eastern reaches of Gondwanaland prior to the opening of the Tasman Sea (Raven and Axelrod, 1974). The lizards are there! Geckos of Mesozoic origin outnumber the “modern” pan-tropical forms in all natural habitats (Bauer, 1986; Bauer and DeVaney, in press). Some skinks too may be of Gondwanan origin, but this is less likely (Greer, 1974). Although Diamond (1984) recognized the fact that there are many lizard species in New Caledonia, he regarded them as relatively recent arrivals that had not undergone significant divergence from their ancestral stock.
Diamond (1984) thus used an incorrect evaluation of the age and diversity of the New Caledonian vertebrate fauna to support his (1977) view that successful radiations in continental (i.e. non archipelagic) situations are area-limited. Diamond (1984) claimed that New Caledonia, with “11 endemic Lygosoma” and 10 species of geckos in three endemic genera, is continental for lizards but not for birds. He further suggested that New Caledonia is the smallest area in which lizards can radiate and that the radiation there was not a major one. This claim is difficult to refute because few small islands in the tropics are “continental” in his sense. Indeed, all of the islands to the south and east of New Caledonia are basically archipelagic, while those to the north and west are either larger than New Caledonia or are also archipelagic.
Although Diamond's (1984) hypothesis that the ability to radiate is area-limited cannot be falsified by data from reptiles, it would appear that any island with
Lepidodactylus lugubris) and are not likely to speciate in their new island homes. Lizards of intermediate vagility, which have successfully colonized islands of intermediate age, have done so only in archipelagic situations and so do not shed light on the question at hand.
Regardless of whether New Caledonia represents the minimal continental area for lizards, its herpetofauna is both old and diverse. Diamond's (1984) vision of New Caledonia as an uninteresting island cannot be maintained in light of the probable Mesozoic origin of its resident geckos. It seems appropriate that the evolutionary history of the groups present be interpreted in the context of paleo-geography before we accept ad hoc hypotheses of recent speciation in this geologically ancient area.
Acknowledgements
I would like to thank Drs K. Padian, A.
References
Blumea 17: 139-178.
Ramphotyphlops braminus(range extension).
Herpetological Review: 18: 41.
Amphibia-Reptilia.
Berichte der Geobotanisches Institut Rubel, Zurich.
Memoires de la Societe Linnaean de Normandie 15: 1-37.
Comptes Rendus de la Societe de Biogeographie 39: 65-69.
EugonylusFitzinger, mit Beschreibung einer neuen Art (Reptilia: Scincidae).
Bonner Zoologische Beitrage 27: 245-251.
Proceedings of the Eight Pacific Science Congress IIIA: 1479-1491.
Copeia 1957: 39-41.
Comptes Rendus de l'Academie des Sciences, Paris 297: 89-92.
Island Life. Natural History Press. New York.
Island Biology. Columbia University Press, New York.
Bulletin of the Geological Society of America 82: 3087-3110.
Reptiles and Amphibians of Australia, 4th ed. Reed Books Pty. Ltd., Frenchs Forest, Sydney.
Science 197: 836-843.
Quarterly Review of Biology 23: 105-123.
Zoogeography, the Geographical Distribution of Animals. John Wiley & Sons. London.
Tuatara 25: 1-6.
Systematic Zoology 26: 263-268.
Biogeography of the Tropical Pacific. Bishop Museum Special Publication 72.
Hemidactylusand
Lepidodactylus. Journal of Experimental Zoology 219: 377-379.
Anolis sagrei. Physiological Zoology 54: 253-259.
American Museum Novitates 2800: 1-6.
Phelsuma sundbergiexposed to sea water.
British Journal of Herpetology 6: 435-436.
Bulletin of the Museum of Comparative Zoology 52: 1-14.
Leiolopismaand its relatives.
Australian Journal of Zoology Supplementary Series 31: 1-67.
Lygosoma. Journal of Natural History 11: 515-540.
Eremiascincus, a new generic name for some Australian sand swimming skinks (Lacertilia: Scincidae).
Records of the Australian Museum 32: 321-338.
Morethia(Lacertilia:Scincidae) from northern Australia, with comments on the biology and relationships of the genus.
Records of the Australian Museum 33: 89-122.
Nova Caledonia, Botanie, volume 3. C.W. Kreidels Verlag, Berlin.
Comptes Rendus de la Societe de Biogeographie 41: 67-75.
New Zealand Journal of Zoology 4: 221-325.
Linnaean Society of New South Wales 24: 391-417.
Pacific Science 21: 423-428.
The Dispersal of Shells, an Inquiry into the Means of Dispersal Possessed by Fresh-water and Land Mollusca.
Miscellaneous Publications of the Museum of Zoology, University of Michigan 173: 1-54.
Proceedings of the Seventh Pacific Congress of the Pacific Science Association 4: 27-31.
Journal of Biogeography 14: 49-87.
Hawaiian Reptiles and Amphibians. Oriental Publishing Company, Honolulu.
Biogeography of the Tropical Pacific. Bishop Museum Special Publication 72.
Systematics and Biogeography. Columbia University Press, New York.
Zoologica (N.Y.) 38: 65-95.
Travaux de l'Institut Scientifique Cherifien, Serie Zoologie 29: 1-132.
Faune de Madagascar 13. Institute des Recherches Scientifiques, Tananarive.
Science 176: 1379-1386.
New Zealand Amphibians in Colour, revised edition. Collins. Auckland.
Nova Caledonia, Zoologie, volume 1. C.W. Kreidels Verlag, Wiesbaden.
Records of the Australian Museum.
Proceedings of the United States National Museum 21: 783-813.
University of Iowa Studies in Natural History 20: 1-14.
Gentique Selection Evolution 15: 93-100.
Zoologische Mededelingen 47: 211-244.
Leiolopisma) from Fiji.
Proceedings of the Biological society of Washington 98: 221-231.
School of Biological Sciences, Victoria University of Wellington
Abstract
Tree ring data was collected from Fijian Kauri (Agathis macrophylla) trees in Northern Viti Levu, Fiji, during November and December 1986. The study was to test the validity of using single increment cores instead of entire trunk sections in growth rate and tree age studies for this species. One increment core per tree was sampled. The nature of the wood formation in this species led to problems in the analysis of the cores and poor statistical confidence in the results. The paper discusses the problems encountered during the study and suggests that alternative methodology should be used for this species in tree ring analysis.
Key words: Dendrochronology, Fiji, Agathis.
Introduction
The study area lies on the north western slopes of Mt Lomalagi, near the Nadarivatu Government Station at the northern edge of the Nadarivatu plaeau in northern central Viti Levu (17° 35′ S, 177° 55′ E). The elevation of the study area lies between 900m and 990m.
The climate of this area lies in zone D of the Fiji Forest Inventory, corresponding to a 2540-3300mm mean annual rainfall, with a moderate 3-5 month dry season having less than 150m rainfall in those months. There appears to be sufficient seasonality in this region for the formation of annual rings in the wood of forest trees.
The basaltic parent materials have produced soils classified by Berry and Howard (1973) as Manosavu bouldery red brown clay, humic latosols, having a low base status and high acidity. These soils have a dark organic rich surface horizon that overlies brown to reddish brown sub-surface horizons which are moderately weathered. A more detailed description of the soils can be seen in the following paper (Weaver, 1988).
The vegetation has been classified as sub-tropical lower montane rain forest by MacDonald (1987). Two adjacent study sites were chosen. One consisted of lush dense secondary forest dominated in the canopy by Homalium vitiense, Calophyllum vitiense, Podocarpus nerifolius, Syzygium sp., and Agathis macrophylla. This site maintained an uneven 4-6m canopy and had a dense undergrowth of seedlings, grasses and herbaceous species. The A. macrophylla population on this site consisted of seedlings, saplings and pole-sized individuals having a basal trunk diameter of approximately 5-30cm. The other site was an old growth forest dominated by emergent A. macrophylla over a 12-16m canopy. The canopy dominants included P. nerifolius, C. vitiense, Syzygium sp., Arytera brackenridgeii and Dysoxylum richii. The Agathis population on this site consisted mostly of trees having basal trunk diameters of 30-130cm.
Methods
In the field an increment corer was used to extract one 5mm diameter wood core per tree from a sample of forty five Agathis macrophylla trees over a range of trunk diameters from both sites. Each core was taken perpendicular to the main axis of the tree and as low to the ground as possible. Each core was then labelled with the diameter at 1.4m height from the tree it was taken from. In the
Results
Ring expression was variable in most cases with some cores only showing distinct rings for part of their length (see Fig. 1). Only 1/3 of the cores sampled showed completely distinct ring formation along the entire length of the core. 40% of the cores sampled had zones where rings were indistinct. On average 35% of the length of these cores was uncountable. The remaining 26% of the cores sampled showed practically no distinguishable ring formation, or visible rings were so widely separated by zones of indistinct rings that ring counts and measurements would have been meaningless. Therefore, this data was considered unreliable and was not used for statistical analysis.
Fig. 1. An example of variation and inconsistencies in ring expression in sanded cores traken from Fijian kauri trees at Nadarivatu. Each core has a 5mm diameter. Core ‘a’ shows a zone of indistinct ring formation at left. To the right large variations in ring distances are seen causing difficulties in determining whether they are annually formed. Some rings are likely to be false (arrow). Core ‘b’ shows no visible ring formation for this section of the core. Core ‘c’ shows variation in the visibility of rings. Core ‘d’ shows evidence of ring wedging and false ring formation (arrowed).
Discussion
Anomalous ring development can frequently cause problems for the dendrochro-nologist if they are not taken into account when constructing a data set from tree rings. False or double rings and the wedging out of rings can lead to very broad error variances in statistical analysis. Irregularities in ring formation can vary from one species to another and between different locations. For example, in New Zealand, studies of Libocedrus bidwillii have shown that false rings are virtually non-existent for this species. Dendrochronological studies of Agathis australis however, have revealed problems with ring wedging as well as a lack of ring pattern consistency around the trunk. Lobate growth in this species is also common as with Phyllocladus aspleniifolius var. alpinus. Dating of these two species may only be possible at some sites (Dunwiddie, 1979). Ash (1985) undertook a study on the tree rings of Fijian Kauri on the Mt Koravaturu plateau in western Viti Levu (alt. c. 800m) and at a site near Suva (alt. c. 150m). By examining trunk discs he found the seasonality sufficient for the formation of annual rings. Here the late wood consisted of smaller compressed xylem elements formed during the dry season in the months between April and October. Ash noted that late wood anatomy was variable with some distinct clearly differentiated bands, but other rings were represented by a gradual transition to late wood anatomy. On most of Ash's sections 5-10% of rings were not distinct. Some trees that were growing on rapidly draining sites produced false rings, and in general, compression wood development necessitated the examination of whole trunk sections to locate all the late wood rings.
In the present study the core samples proved extremely variable and anamalous in ring expression. Because only one core was taken per tree it was impossible to establish the validity of each ring as truly annual. Understanding the nature of wood formation in Fijian kauri described by Ash (1985), growth rate data from a single core are not likely to be representative of the entire trunk even if ring clarity is good for those cores samples. Whitmore (1975) suggested that ring counts are inapplicable or unreliable in the tropics when attempting to determine tree ages.
Conclusion
The technique of sampling one core per tree to study growth rates and tree ages in Agathis macrophylla in lower montane rain forest proved to be inadequate for confident statistical analysis of the data. Entire trunk discs should be used if possible. If entire trunk discs are not available then at least 3 cores per tree should be sampled to allow for anaomalies in ring formation such as eccentricity, ring wedging, lobate growth and locally absent rings.
Acknowledgements
This paper forms part of a B.Sc. Honours project at Victoria University, Wellington. I am therefore grateful to the following people in the Botany Department: Dr. Ross McQueen for supervision of the project; Stephen Fuller for useful comments on the draft; Ian MacDonald for assistance in the field. The Royal Forest and Bird Protection Society and the Wellington Botanical Society provided financial assistance.
References
Agathis vitiensis(Seeman) in Fiji.
Australian Journal of Botany 33: 81-88.
Fiji Forest Inventory. Vols. 1, 2 and 3. Overseas Development Authority: Surbiton, U.K.
New Zealand Journal of Botany 17 (3): 251-66.
MacDonald, I. 1987. Observations on the forest dynamics and regeneration of Fijian Kauri(Agathis vitiensis)
within old growth forest, Viti Levu, Fiji. Unpublished B.Sc. Honours project. Victoria University, Wellington, New Zealand.
An introduction to the regeneration of Fijian Kauri following logging. Unpublished B.Sc. Honours dissertation. Victoria University, Wellington, New Zealand.
Agathis macrophyllaforest at Hadarivatu, Fiji.
Tuatara 30: 55-61.
Whitmore, T.C. 1975: Tropical Rainforests of the Far East. 1st ed. Oxford University Press.
School of Biological Sciences, Victoria University of Wellington
Abstract
A comparison was made between soils beneath second growth and mature Fijian kauri (Agathis macro-phylla) forest. It was assumed that there were no significant soil differences between these sites prior to the selective logging of part of this area. The soils beneath the second growth stand showed a higher degree of leaching in the upper two horizons and a thicker, yet less well defined, organic topsoil horizon compared with the soils of the mature stand. The lower horizons in both sites were similar. The differences observed are likely to have resulted from the logging activities and subsequent modification of the vegetation in the second growth stand.
Key words:Agathis, Fiji, Soil, logging secondary succession.
Introduction
The two sites being compared were once continuous sub-tropical rain forest dominated by emergent Fijian kauri (Agathis macrophylla). During the logging exercises, commercial species including Fijian kauri, having a diameter at breast height (dbh) of 35cm or greater were removed. The logging is believed to have occurred between 1935 and 1960. The area that was logged now carries secondary re-growth containing regenerating Fijian kauri up to 30cm dbh. The soils were studied to determine whether differences exist between the soils of these two sites, and whether these differences were a result of logging.
The study area was located on the North Western slopes of Mt Lamalagi, near the Nadarivatu Government station in Northern Central Viti Levu (17° 35′ S, 177° 55′ E) between 900 and 990m altitude. The mean annual rainfall of this area is 2540mm-3300mm with a 3-5 month dry season. Mean monthly maximum temperatures range from 25°C in December to 22°C in July, with mean maximum temperatures range wing the same pattern with 17 and 14 respectively. Mean relative humidity remains higher than 80% year round (Berry and Howard 1972). A more detailed vegetation description is summarised in a previous paper in this issue (Weaver 1988).
The soils of the study area have been classified as humic latosols developing from basic parent materials including olivine basalt (Twyford and Wright 1965). These soils have developed on steep 25-40 degree slopes in a moist environment beneath sub-tropical lower montane rain forest. Humic latosols are commonly red or reddish soils having a clay texture but may be classified as loams in the field. They tend to exhibit a low base saturation, with moderate to high cation exchange capacity and are moderately to strongly acid. They are derived from parent materials ranging from olivine basalt lavas to acid-intermediate rocks such as acid agglomerate. Such soils are of widespread occurrence in Fiji and are found throughout the climatic range of the territory. Twyford and Wright (1965) have described the soils of the Nadarivatu area itself as being derived from olivine basalt.
Methods
Soil profiles were described from 10 soil pits, carried out in both the mature forest and in the second growth stand. The soil pit sites corresponded to vegetation analysis plots that were randomly located within the two forest types. Soil profile descriptions included colour, texture, structure and horizon depth. Soil samples were collected for each horizon from 6 of the 10 sites for chemical analysis. The chemical
Results
Physical soil properties
Soils beneath both vegetation types possessed similar structure. They were generally massive, with very friable, weakly developed, crumb structure. Boundaries were diffuse and colour change was slight down the profile except for the organic H1 horizon. Soil colour in the mature stand generally followed a brownish black 1-2cm humus, overlying a dark brown to brown 100-150cm sub-soil. Basement rock was not reached even at 150cm where the horizon at this depth corresponded to a B2 horizon (Gibbs 1980). In the soils beneath the secondary stand the organic horizon was thicker and of a lighter colour, generally following a dark brown to brownish black 1-14cm organic horizon, overlying a dark brown to reddish brown sub-soil.
The thicker but less darkly stained organic horizon in the secondary stand may have resulted from different species compositions between the sites or from modification of the soil caused by logging. Higher soil surface temperatures are likely beneath this vegetation type, due to a lower degree of shading compared with the mature stand. This also allows a higher proportion of surface rooting herbaceous plants to contribute to top soil formation. Similarly the thin (1-2cm) carbon rich humus blanket, recorded in the mature forest, suggests that a cooler and wetter top soil micro-environment exists in this heavily shaded situation.
The evidence of fire (charcoal fragments) seen in the modal profile for the second growth stand is likely to have been a result of localised fire caused by lightning strike. Trees scarred by lightning were a relatively common feature throughout the study area. This is not surprising considering the frequency of thunder storms in the region (Revel 1981). There was no evidence of fire in any other soil profile.
Modal Profile: Mature Forest
Modal Profile: Secondary Stand
The mean values for soil chemical properties for both sites. A = mature stand values. B = secondary stand values.
During leaching, water percolates down through the soil and mobilises soluble cations (base nutrients) to lower horizons, making them unavailable to plants. Calcium, sodium, magnesium and potassium occur as simple, highly mobile ions and are readily removed in this process. Once these cations are leached, their positions on the soil colloid particles are replaced by hydrogen ions. An increase in the number of hydrogen ions present, increases the acidity of the soil. Thus, acidity can be used as an indicator of the degree of leaching, with increasing acidity (lower pH values) tending to correlate with increased leaching.
Soil acidity was consistently higher in the upper horizons of the successional stand. There is a correspondingly low value for bases in these horizons (see table 1). It would appear that the secondary stand soils are slightly more leached in these upper horizons than in the mature forest.
Cation Exchange Capacity (CEC) measures the ability of the soil to absorb cations (i.e. bases) to the colloid particles within the soil, thus indicating the ability to hold nutrients. In the organic H1 horizon of the mature forest site the value of 86.7 m.e. % is substantially higher than the equivalent reading for the secondary stand (i.e. 37.6 m.e.%). However readings become similar in the lower horizons.
Total Exchangeable Bases (TEB) measures the base nutrients present within a soil at the time of sampling. A similar pattern is seen with TEB ratings between the sites. Again the lower horizons have similar values, whereas the H1 horizon has a considerably higher value of 85 m.e.% in the mature forest, compared with 12.3 m.e.% in the secondary stand.
Percentage Base Saturation provides a valuable indicator of “base status’ which is often related to the amount of leaching. Lower Base Saturation values correspond with higher leaching. The Base Saturation values were only recorded for the mature stand. Characteristically the H1 horizon shows a high Base Saturation rating of >98 m.e.% as a result of the corresponding CEC values and the TEB, of which calcium and magnesium make up the largest proportions (>50 m.e.% and 11.2 m.e.% respectively). The lower horizons exhibit lower values with a mean Base Saturation of 26 m.e.%.
Both the calcium and magnesium components continue the trend observed in the CEC and TEB readings. Values for sodium are lower for horizons in the secondary stand. Potassium values however are higher in the secondary stand for each horizon with high values in the H1 and lower values in the H3 horizon.
Phosphate in New Zealand soils may be classified into 4 classes. These are Low (0-30%). Moderate (30-60%), High (60-90%) and Very High (90-100%). By these standards the soils in both sites studied here show very high phosphate retention. Phosphate rentention in acid soils is related to compounds of iron and aluminium (Saunders, 1968). Tamm's extractable iron and aluminium show high values and are possibly associated with the binding of phosphorus.
Water retention in a soil increases as the clay content increases. High clay content correlates with high CEC by increasing the number of colloid particles that can absorb cations. 15 bar water retention values obtained for the lower horizons of both sties range from 27.5% to 38.9%. These values would seem to represent moderate retention of water and relatively high clay content. A comparison of soil water retention values between soils in this study area and soils studied by Gangaiya et al (1982) suggest that Nadarivatu soils in general have a relatively high clay content and concurrently moderate water retention status for Fijian soils. Another factor that influences water retention is organic matter. In this study the topsoil readings for 15 bar water retention also correlate with the pattern of carbon content between these two soils, with higher values in the organic rich H1 horizon of the mature forest stand.
Discussion
The soils studied at Nadarivatu show features of both basaltic and andesitic origin. Exchangeable potassium values in the mature stand are more closely related to the range of exchangeable potassium characteristic of basalt soils (0.2-0.57 m.e.%). The exchangeable potassium of soils on this site do not exceed 0.2 m.e.%. The values recorded from the secondary stand are higher in the upper two horizons but do not fit completely into the potassium range characteristic of andesitic tuff soils (0.75-1.5 m.e.%). As the soils of the study area are located on slopes of >25 degrees, the soil mantle is unstable causing a constant drift of soil particles down the slope. Evidence for unstable slopes was seen throughout the study area. Thus, the direct influences of parent materials are not easily discernable due to constant renewal and truncation of the soil mantle, at least in the zone near the soil surface.
Some Agathis species including A. australis in New Zealand (Eckroyd, 1982), A. borneensis and A. alba in Borneo (Whitmore, 1966) are known to podsolise soils. The nature of the soil parent material tends to influence the degree of podsolisation. In Borneo base poor parent materials combined with high leaching allows the mor-forming Agathis leaf litter to podsolise the soil. However, no evidence of podsolisation was seen in the Nadarivatu soils. The steep slopes of the study area contribute to soil rejuvenation through slipping and soil creep, thus masking any physical effects of podsolisation. Also a large proportion of the forest community present may be non-podsol formers. Whitmore (1966) found no evidence of podsolisation beneath A. macrophylla forests on Vanikoro Island in the Solomon group, where a similar situation exists.
In general the soils of these two forests differed. However, differences were observed predominantly in the upper two horizon, particularly in the organic H1 horizon. This horizon was thicker in the second growth stand and had a lower carbon content than the equivalent horizon of the mature forest soil. There was also evidence of a higher degree of leaching in the upper horizons of the second growth stand with lower base values and higher acidity compared with the mature stand. Whitlock (1985) noticed similar patterns in a successional sequence of regenerating Agathis australis in New Zealand. Here the organic zone in the upper horizons increased in nutrients over successional time. The horizon boundary between organic H1 horizon and its underlying horizon tended to be more distinct in the soils of the mature forest. However, the lower soil horizons of the two sites showed no major differences.
The differences observed in these soils must either pre-date the logging or, result from the logging activities. If these differences existed prior to logging, it may have resulted from a soil parent material disparity between the two sites, or there may have been significant differences in the species composition. The latter is unlikely, as the local area comprising the north western slopes of Mt Lomalagi at these altitudes maintains forest of the type present in the mature stand. Other indigenous vegetation in this area is second growth forest that maintains many similar species to that of the surrounding old growth forest (Weaver, 1987; MacDonald, 1987). If differences existed between the soil parent materials, evidence in the lower horizons would be expected. This was not observed in the present study.
Logging is more likely to have been the determining factor of the soil differences seen in this study. The direct effects of logging would include soil scarification (mixing of humus and mineral soil) resulting from heavy machinery activity, and a large build up of litter from discarded branches, damaged trees and crown foliage of logged trees.
A deeper organic topsoil horizon in the second growth stand would result from this process combined with scarification of the soil surface. The lower carbon content and base values in this soil may result from subsequent leaching and run off which would have increased following the removal of a large proportion of the protecting canopy.
Acknowledgements
This paper is the result of work carried out for part of a B.Sc. Honours thesis in Botany at Victoria University, Wellington. I would like to thank Ian McDonald for assistance in the field and a substantial contribution to the results. Dr Ross McQueen supervised the thesis and Stephen Fuller provided valuable discussion and useful comments on the draft. I would also like to thank Professor
Bibliography
Fiji Forest Inventory. Vols. 1, 2 and 3. Overseas Development Authority: Surbiton, U.K.
Agathis australis, New Zealand Journal of Botany 20 (1): 17-36.
New Zealand Journal of Science 25: 61-64.
New Zealand Soils. An Introduction. Oxford University Press. Wellington, New Zealand.
Observations on the forest dynamics and regeneration of Fijian kauri(Agathis vitiensis)
within old growth forest, Viti Levu, Fiji. Unpublished B.Sc. Honours thesis. Victoria University, Wellington, New Zealand.
Tropical Cyclones in the South West Pacific, November 1969 to April 1979. New Zealand Metrological Service. Miscellaneous Publication number 170. Wellington, New Zealand.
New Zealand Soil Bureau Bulletin 26 (2): 109-114.
The Soil Resources of the Fiji Islands. Government Printer, Suva, Fiji.
An introduction to the regeneration of Fijian kauri following logging. Unpublished B.Sc. Honours thesis. Victoria University, Wellington, New Zealand.
Agathis macrophylla). Tuatara 30: 51-54.
Soil development in a kauri forest succession. Huapai scientific reserve. Unpublished M.Sc. thesis. University of Auckland, New Zealand.
Agathisin a rain forest in Melanesia.
Journal of Ecology 54: 285-301.
Hamburg University P.O. Box 30 46 28 D-2000 HAMBURG 36 West Germany
Abstract
For the first time, geological and palaeontological evidence is presented that makes the presence in New Zealand of a marsupial just possible and that of a platypus-like monotreme possible and likely. The latter alternative is preferable, so that the waitoreki a non-descript supposedly mammalian animal of New Zealand, could be an analogue of the Australian Duck-billed Platypus (Ornithorhynchus anatinus), perhaps even more ancient than the platypus.
Key note:Chronectes minimus, fossil monotreme, New Zealand otter, platypus, Steropodon galmani, Yapok.
Dedication
Dedicated to Dr phil.habil., Dr. med. INGO KRUMBIEGEL (Hamelin, Germany), Nestor of Cryptozoology, on the occasion of his 85th birthday, 26th February, 1988.
Observations and Discussion
It is generally understood, particularly in New Zealand, that at least some of the 19th century sightings of the mysterious otter-like waitoreki refer to the Australian Opossum or Phalanger (Trichosurus vulpecula), which was first liberated at Riverton, Southland, in 1858 “with the idea of starting a skin trade’ (McLintock, 1966). However, earlier reports, and the waitoreki's reported aquatic way of life, as well as its Maori names waitoreki and kaurehe point to the existence of a different animal, which must have reached and colonized the area of present-day New Zealand prior to its becoming islands in the course of the Cretaceous. This would rule out all mammals. Placentalia in particular are known to have diversified later in geological time. Likewise, neither monotremes nor marsupials are considered to have reached Australia when New Zealand was still part of that landmass. The limited aquatic ability of mammals in general and monotremes and marsupials in particular should have prevented trans-oceanic dispersal. As Watson (1960) aptly summarized the communis opinio, “The extreme improbability of this has caused most New Zealand biologists to dismiss all the reports [on the waitoreki] as illusory’. However, recent findings have changed the premises of this assumption, and the intriguing possibility has arisen that a monotreme or marsupial might in fact have reached early pre-New Zealand. In order to decide the question whether the waitoreki might thus actually constitute a mammal unknown to science, it is a necessary prerequisite to disentangle the palaeobiogeography of marsupials and monotremes.
Marsupials are usually considered as having originated in South America. Biogeographers at first favoured dispersal route, with the early marsupials travelling from the Americas across Asia to Australia. Recently the first fossil marsupial from Asia has been reported from central-Asiatic U.S.S.R. (Benton, 1985). A southern dispersal route, from South America to Australia via Antarctica, was preferred by others influence by Wegener's theory of continential drift. The immigration, however, presumably took place too late in geological time to involve New Zealand, which had already drifted apart from Australia. By the end of the Cretaceous period, about 70 million years ago, connections with large land masses beyond New Zealand ceased to exist. This is the “official” explanation one will
(Chronectes minimus). It ranges today from S. Mexico to Brazil and NE Argentina, and frequents fresh-water streams and lakes; in some areas it is found “at considerable altitudes’ (Walker, 1964). Head-+-body length is c. 30cm, with an additional length of tail of c. 37.5cm. The dense pelage is pearl-grey with a pattern of blackish bands on the back; chin, chest and belly are creamy white. The tail is rat-like, furred only at the base. The hind feet are webbed. Yapoks are the only aquatic marsupials and are excellent swimmers and divers. They prey on crayfish, fresh-water shrimp and fish, with probably some additional plant material (Walker, 1964). Yapoks are nocturnal, they spend the daytime in subterranean dens tunnelled into river banks, with an exit just above the water-line and a tunnel diameter of c. 15cm. These animals will certainly not hesitate to enter any kind of vegetable “raft” afloat in a jungle bayou, and become involuntarily seaborne (by this method yapoks might have reached the island of Trinidad where they are said to occur. Cf. Walker, 1964). An early precursor of Chironectes might have crossed the gap between Australia-Antarctica and pre-New Zealand by means of a natural “raft”, thus braving a shallow sea of scattered islands and tidal reefs with the help of palaeo-winds and palaeo-currents during a few days' voyage. Six years ago. a South American marsupial (a polydolopid) was found in Eocene deposits (about 40 Myr ago) of Antarctica (Woodburne & Zinsmeister, 1982), a find that suggests a similar “braving of open sea” between the southermost tip of South America and an ice-free Antarctica (situated in more northerly latitudes than today).
Should the southern dispersal route to New Zealand prove valid (at least for animals with aquatic adaptations), the waitoreki might turn out to be akin to the yapok, and it should be worthwhile to have a closer look at the yapok's natural history and ecology in order to determine those of the waitoreki.
On the other hand, new evidence suggests that the waitoreki may rather be a monotreme. Recently (1985), Australia's first fossil Mesozoic mammal, a platypus-like monotreme, was described (Archer et al., 1985). It was discovereed in early Cretaceous sediments in New South Wales and was named Steropodon galmani (n.gen. and sp.). The fossil find represents an early ornithorhynchid-like (platypus-like) monotreme of rather large size. The fact that distinctive badger-sized monotremes were present in Australia in the early Cretaceous (when New Zealand was presumably still part of that landmass) indicates not only an antiquity of this group hitherto unheard of and certainly great enough to have settled New Zealand without having to brave an open sea, but also testifies to an evolutionary trend which obviously favoured this group of Monotremata. For contemporaneous dinosaurs of the same local fauna include very small forms (hysilophodontid dinosaurs) which were probably not at all larger than the sympatric monotremes.
Should this theory hold true, the waitoreki might eventually prove to be a New Zealand analogue of the Australian platypus. Its natural history and ecology will perhaps be found to be similar to those of the Duck-billed Platypus (Ornithorhynchus anatinus). The modern platypus has a head-body length of 30-45cm, with an additional tail length of 10-15cm. The flat tail is shaped like a beaver's although completely furred. The colour of the fur is deep amber or dark brown on the back, the belly is white to yellowish chestnut. They feed on crayfish, shrimp, snails, worms, tadpoles, insect larvae and small fish, which they gather from the bottom of
et al., 1985). Of course, the waitoreki does not build dams, nor does it construct “houses like bee-hives’ (Taylor, 1855). This statement should be considered a wilful mystification on the part of a witness who admittedly had never seen a waitoreki and might therefore have tried to improve on his “meagre” knowledge. Rather, the waitoreki might live in burrows like those which the platypus is known to construct in banks along streams and ponds and which, contrary to those of the yapok, open below water level. Platypus burrows with holes opening below water-level are found in the Australian Alps, whereas on the plains, burrows are said to open mostly above water-level. Similarly, a hole below water-level was reported for the waitoreki. In c. 1918 an eye-witness saw an animal swimming in Waikiwi Creek, Grassmere (not far from Invercargill) “and later saw a hole like a rabbit-hole below the water-level not far away’ (Wall, 1926). Further, the waitoreki will possibly be found to have four webbed feet as the platypus has. Correspondingly, the waitoreki might possess a small bill (similar to that of the platypus) hidden in the fur and thus hardly discernible from some distance. An animal evolutionarily perhaps even more “old-fashioned” than the platypus, the waitoreki might feature well-developed teeth, the dental formula including three molars, the number evidently present in young Ornithorhynchus anatinus (which is the only known monotreme to retain even vestigial teeth). Lastly, the waitoreki might be found to lay eggs as the playtpus does, and nourish its young in the same way. In 1848, when
As there is now fossil evidence for a flourishing platypus-like group in Australia which pre-dates the separation of New Zealand, the second alternative, i.e. the waitoreki a platypus-like monotreme, seems at present to have the highest degree of probability, should the waitoreki actually constitute a mammal unknown to science. Therefore the mysterious animal might, as i.e. the Archaeopteryx from Jurassic limestone quarries near Solenhofen, Bavaria, Germany. As Alfred Wallace wrote on the waitoreki, “it is to be hoped that this creature will not be allowed to become extinct without a determined effort being made to secure specimens in order to study its structure and its relationship to other animals’ Wallace, 1888). Due to the indifference of most New Zealand scientists, past and present, it could well be too late now.
Acknowledgements
The author thanks Mrs Josie Laing, Canterbury Museum, Christchurch, New Zealand, and Ms. Christine Tuitubou, National Library of New Zealand, Wellington, for their kind help in providing reference material.
References
Nature318: 363-366 (+ cover).
Nature318: 313 (quoting the original Russian description: Gabunia, L.K. & Shevyreva, N.S.,
Doklady Akad. Nauk. S.S.S.R. 281 (1985): 684).
The Life and Letters ofCharles Darwin . London, 3 vols.
An Encyclopaedia of New Zealand. Wellington: NZ Government Printer, 3 vols.
Petrifactions and their Teachings; or a Handbook to the Gallery of Organic Remains of the British Museum(spine-title
Mantell's Fossils of the British Museum). London: British Museum (National History).
Nature318: 361-363.
Mammals of the World. Baltimore: The John Hopkins Press, 3 vols.
The Press(Christchurch, N.Z. 8th Sept., 1926).
Australasia. 5th ed. London: Stanford.
Records of the Canterbury Museum 7: 175-183.
Science218: 284-287.
Additional references from the publications of ISC Honorary Member Dr. phil. habil, Dr. med. Ingo Krumbiegel, to whom this article is dedicated.
Zoologischer Anzeiger, 132, 3/4: 63-72.
Arche Noah, 1, 3: 44-45.
Arche Noah, 1, 5: 102.
Arche Noah, 1, 8: 170.
Von neuen and unentdeckten Tierarten. Kosmos. Stuttgart (pp. 70-75).
Zeitschrift fur Saugetierkunde(Berlin). 18: 110-115.
Science and Research Directorate, Department of Conservation, P.O. Box 10 420, Wellington.
Abstract
The stages of development of male cones, ovules and seeds in six New Zealand coniferous trees are described and illustrated. In kahikatea (Dacrycarpus dacrydioides), totara (Podocarpus totara), Hall's totara (P. hallii) and tanekaha (Phyllocladus trichomanoides) the visible stages are completed in one growing season, fertilisation occurring about 6 or 8 weeks after pollination. In miro (Prumnopitys ferruginea) and matai (P. taxifolia) the visible stages of ovule and seed development occupy two growing seasons and fertilisation occurs 12 months or more after pollination.
Key words: Podocarpaceae, Podocarpus, Dacrycarpus, Prumnopitys, Dacrydium, Phyllocladus, conifer. seed, ovule, male cone, phenology.
Introduction
There are distinct differences in the reproductive structures and in the timing of the sequence of events which leads to the production of ripe seed in six of New Zealand's tall forest coniferous trees. In this article the development of male cones and female ovules in kahikatea (Dacrycarpus dacrydioides), true totara (Podocarpus totara), Hall's totara (P. hallii), miro (Prumnopitys ferruginea), matai (P. taxifolia) and tanekaha (Phyllocladus trichomanoides) will be described. The development of these structures in rimu (Dacrydium cupressinum) has already been described (McEwen, 1983).
The ovule-bearing structures of podocarp trees are modified, reduced female cones. In matai, in particular, the structure resembles a minute enlongated cone with several ovules borne spirally on a cone stalk, each in the axil of a bract scale or carpidium.
In the Coniferales there are two types of reproductive cycles, a short and a long type, and both are represented among these New Zealand tree species. In the short type the whole reproductive cycle occupies approximately one year and the time between pollination and fertilisation is only 6 or 8 weeks; whereas in the long type the cycle occupies two years and the time between pollination and fertilisation is 12 months or more. The long reproductive cycle also occurs in rimu (Dacrydium cupressinum) (McEwen, 1983).
The dates given in this article refer to the Rotorua district in 1977 and 1978 and the timing of events in other parts of the country are likely to vary somewhat, being earlier in the north and later in the south or at higher altitudes.
Materials and Methods
Male and female sample trees of kahikatea, totara, Hall's totara, miro, matai and tanekaha were chosen with cone-bearing branches within reach from ground level or from a pruning ladder. All trees were within 30 km of Rotorua: miro trees were located in Dansey's Road, Hall's totara and matai on Fletcher's Road, tanekaha on Clinkard Road (all these being in the Mamaku area to the north-west of Rotorua); totara in the Forest Research Institute grounds, Whakarewarewa, Rotorua; and kahikatea at Te Ngae on the east of L. Rotorua.
Certain branches on the sample trees were tagged so that the ovules and cones they carried could be examined during each visit. Similar ovules and cones were collected from nearby branches for study.
Collecting visits were made on 18.11.77, 12.12.77, 21.3.78 and 14.8.78.
Results and Discussion
(Results are summarised in Table 1)
Table 1. Summary table of reproductive cycle of New Zealand tree podocarps. Rimu has been included in the table for completeness.
Kahikatea has a short reproductive cycle with the visible stages of cone and ovule development being completed in one growing season. The species is dioecious, the trees being either male or female, and in certain seasons, in spring time, October and November, the difference between the sexes may be seen from a distance. Male trees bear brown cones in such abundance that the whole tree may appear brownish, whereas female trees carry numerous glaucous ovules which give the tree a bluish tint. Sterile trees and branches appear bright green in spring when the new shoots are flushing.
Both male cones and ovules are produced terminally on the shoots. They develop rapidly in the spring and pollen is shed from mid October to November (Fig. 1).
The ovules are borne either singly or in pairs or occasionally threes in a specialised receptacle formed from the upper 2 or 3 leaves only (Figs. 2 and 3). The micropyle in kahikatea is directed towards the base of the ovule as in the young rimu ovule (McEwan. 1983), but in kahikatea the ovule-bearing shoot-tip is not upturned so the pollen falls from above almost directly towards the micropyle. The micropyle remains at the base of the mature seed, unlike rimu in which the micropyle is near the top of the mature seed.
During summer the ovule grows, fertilisation takes place (probably in January) and the seed expands and the surrounding epimatium (a modified ovuliferous scale) and carpidium (or bract-scale) ripen from March to May from a glaucous green to a dark purplish black, almost round seed, borne on a rounded red receptacle (Fig. 3 and 4).
In kahikatea neither the receptacle nor the male cone are stalked. Where a single seed is borne on each receptacle, one or two undeveloped ovules also occur, appearing as small glaucous protuberances (Fig. 4).
Totara,
Podocarpus totara and Hall's Totara, Podocarpus halliiThese two species are closely related and have similar short reproductive cycles. Both are dioecious with separate male and female trees. Whereas in rimu and kahikatea there is no visible sign in winter of where male cones will appear the following spring, in the totaras distinctive small club-shaped shoots can be found on male trees on the previous season's growth. These consist of a minute male cone enclosed in several bud-scales and terminating a short stalk. The stalks of Hall's totara male cones are longer than those in true totara.
In spring the male cones break bud, expand rapidly and shed their pollen. In totara bud break occurs in late October and the male cone is somewhat elongated in shape. Pollen is shed in early November (Fig. 5).
In Hall's totara, which usually grows at higher altitudes than totara, bud break is in early December and pollination a few weeks later. The young male cone in Hall's totara is rounded in shape (Fig. 6).
Whereas the male cones develop as short specialised shoots at the end of summer and are visible in their buds throughout winter, the ovules in these species appear in the spring. They are situated towards the base of the new season's growth as it expands from the overwintering bud (Fig. 7). In both species the ovules are borne singly or in pairs on a specialised receptacle set on a short stalk. At the time of pollination the ovule plus receptacle and stalk is only about 3mm long in true totara (Fig. 8) and a little longer in P. hallii. The ovules are fully exposed and their micropyles are directed downwards towards the receptacle, as in kahikatea.
Development in both totara species is rapid, fertilisation occurring within several months of pollination and the fruit ripening between about March and May. The
Kahikatea
Fig. 1 Male cones in kahikatea (mid October), shortly before pollination. Cones 5-8mm long. a. male cones.
Fig. 2. Ovules in kahikatea shortly before pollination (mid October). Ovules 1-2mm long. a. small glaucous ovules.
Fig. 3. Kahikatea ovule in mid October shortly before pollination. About 10 scale leaves surrounding the ovule have been removed. Whole structure 2mm long. The ovule is surrounded by the glaucous epimatium and half-covered by the carpidum which remains fused to it while the whole structure develops. a. bract, b. carpidium (green, slightly glaucous), c. epimatium surrounding ovule (glaucous), d. micropyle mouth (extension of integument).
Fig. 4. Ripe kahikatea fruit in late March, a. carpidum, b. dark purplish epimatium surrounding seed, c. red fleshy receptacle like a small raspberry. Receptacle and seed approx. 8mm.
Totara and Hall's Totara
Fig. 5. Male cones of true totara, two shedding pollen in early November. Note position of cones (indicated by arrow) in relation to the glaucous new spring growth.Fig. 6. Male cones of Hall's totara breaking bud in December. On the right specimen a club-shaped shoot can be seen below the right hand cone. Male cones look like this during the preceding winter. Note the longer cone stalks and rounder shaped cones than in the true totara and the position of the cones in relation to the new spring growth.Fig. 7. New ovules of true totara in mid October. Ovules occur on a receptacle set on a short stalk; they are found towards the base of the newly expanded new growth.Fig. 8. New ovule (in mid October), set on a receptacle on a cone stalk and partially surrounded by a free, soft, scale-like carpidium. a. carpidium, b. micropyle just visible, c. ovule, d. receptacle, e. cone stak. Whole 5mm long.
Fig. 9. Ripe fruit of true totara (March). Note the rounded (green) seed and stalked receptacles, a. carpidium, b. green seed (4mm), c. red smooth succulent receptacle.Fig. 10. Ripe fruit of Hall's totara (March). Note the elongated (green) seed. a. carpidium, b. green seed (5-6mm), c. orange-red smooth succulent receptacle.
In both species there may be a second flushing of shoots in late summer or autumn and a second crop of new ovules may be produced by female trees.
Club-shaped shoots may occasionally also burst into a second crop of male cones which pollinate the ovules. Such autumn pollinated ovules sometimes ripen in spring to produce seed with fleshy red receptacles (September-November).
It is also possible for unpollinated (and therefore unfertilised) ovules to develop ripe red receptacles either in autumn from a normal spring flushing, or in spring from an autumn flushing.
Miro,
rumnopitys ferruginea (Podocarpus ferrugineus)Miro, like rimu, has a long reproductive cycle (McEwen, 1983). The trees are usually dioecious but occasional trees are found which bear mostly ovules but have a few branches bearing male cones, and vice versa.
The ovule in miro develops on the previous season's growth on a special short shoot which appears like a tiny pinkish flower in November. The stalk has minute spiralled scales while the ovule itself is entirely surrounded by a glaucous epimatium and has several larger petal-like scales at its base. The whole structure is about 12mm long when pollinated in November (Fig. 11).
As in the totaras the male cones of miro are visible throughout winter (about 5mm long) (Fig. 12). They are carried on short stalks on the previous season's growth and appear like short waxy candles. These grow to about 15mm in the spring, before shedding pollen in November.
Miro
Fig. 11. Recently pollinated ovule of miro (December). Note the spiralled scales on the ovule stalk and the pinkish glaucous, petal-like scales (sterile carpidia) at the ovule base. a. ovule, b. scaled stalk (5mm).
Fig. 12. Immature male cones of miro (September). The cones are visible throughout winter and shed pollen in about November.
Fig. 13. Two stages of seed development in miro (March). The samll glaucous (green) ovule on the right is in its first season's growth, having been pollinated the previous November. The ripe (red) fruit on the left is a year older and fully developed.
After pollination the ovule begins to expand and its surrounding epimatium becomes a glaucous green. Most of the petal-like scales fall, leaving only one or two at the base of each ovule (Fig. 13). When it is about 5mm long the ovule ceases growth for a few months during winter, from about June to September. Fertilisation is thought to occur in December to January, more than 12 months after pollination.
Matai
Fig. 14. Two soft spikes of matai ovules, appearing like elongated cones (mid December).Fig 15. Male matai cones close to pollen shed in late November.Fig. 16. A spike of male cones of matai (April). These cones (1.5-2.5mm long) are visible throughout winter, a. cones (approx. 2mm long), b. subtending bract, c. leaf subtending male spike.Fig. 17. Spike of matai ovules in their first year of development (April, following pollination in November). Several of the original ovules have aborted since the spike first appeared in November, a. carpidium, b. ovule (3mm), c. bract of aborted ovule.Fig. 18. Two stages in seed development in matai (December). The two small ovules on the right were recently pollinated; the large (green) one on the left is in its second summer, pollinated over 12 months earlier and close to fertilisation. It will ripen to a dark purplish black seed in autumn. Note that most of the original 8 or so ouvles have aborted.(Hemiphaga novaeseelandiae.
Matai,
Prumnopitys taxifolia (Podocarpus spicatus)Matai is closely related to miro and is similar in having a long reproductive cycle. Trees are usually either male or female but, as in miro, a few trees bear some reproductive organs of both sexes.
The male cones of matai are very conspicuous. Towards the end of summer small spikes develop, consisting of up to 18 cones arranged spirally on a lateral shoot. Each cone has a small bract-like leaf at its base and the whole spike is terminated by a cone. During winter the cones are between 1 and 2mm long (Fig 14).
The female structure is also spike-like and has up to 8 ovules, each borne in the axil of a small bract, arranged spirally on the axis. A pale green epimatium completely surrounds each ovule and the micropyle is directed downwards. These female structures, like elongated cones, appear in November as fragile new shoots (Fig. 15). Pollen is shed from the enlarged male cones in late November or early December (Fig. 16).
During summer some of the ovules grow but many of them abort or cease development during their first year (Fig. 17). They are about 3-5mm long when growth stops in June for several winter months. During the second summer ovules continue to expand and round out; fertilisation occurs probably in December or January (Fig. 18). In Fig. 18, taken in mid December, the two small ovules on the right are in their first season of growth and have recently been pollinated whereas the larger single ovule on the left is in its second growing season at approximately the time of fertilisation and should ripen by the following March.
Ripe matai fruits are about 8-10mm in diameter, rounded and dark purple or black. They are difficult to find, possibly because they are readily eaten by fruit eating birds such as New Zealand pigeons and tuis as soon as they are ripe.
Tanekaha,
Phyllocladus trichomanoides
The reproductive cycle in tanekaha occupies only one year, as in kahikatea and the totaras. Tanekaha trees are usually monoecious, both male and female reproductive organs being borne on a single tree. However individual trees are often predominantly either male or female while also bearing a few cones of the opposite sex.
New phylloclades expand from the overwintering buds in spring (October or November) and some bear six or eight glaucous ovules with micropyles directed upwards (Fig. 19).
Groups of small purple male cones are produced at the same time in the place of groups of phylloclades (Fig. 20). Several weeks later pollen is shed from the expanded male cones and the ovules are pollinated by way of a pollination droplet (as is the case in the other podocarps). These droplets can be observed shining in the micropyles at the time of pollination. Fertilisation probably occurs in January and during the summer the ovule grows and develops into a shiny black seed. It is surrounded at the base by a cup-like structure, the aril (Fig. 21). When the seed ripens the aril becomes slightly swollen and white with a green frilly edge (Fig. 22).
Tanekaha
Fig. 19. Specialised ovule-bearing phylloclades of tanekaha breaking bud in spring (October).Fig. 20. Immature male cones of tanekaha having recently broken bud (October).Fig. 21. Developing tanekaha seed (March).Fig. 22. Close-up of two tanekaha fruits (March). The lower fruit is not quite mature and the white aril and dark seed has not fully emerged from the green receptacle whereas the upper fruit is fully ripe.
This attracts birds to eat and disperse the seed. A common feature of tanekaha however, is the large number of undeveloped or empty seeds and insect damage is common.
Acknowledgements
I thank members of staff of the Forest Research Institute, Rotorua: Messrs A.E. Beveridge and M.C. Smale for assistance and advice, H. Hemming and J. Barran for the photography and J. Leathwick for commenting on the text. I am grateful to Dr R. Sadlier, Director, Science and Research Directorate, Department of Conservation, for allowing me time to complete this work and to Dr B.V. Sneddon. Victoria University, for his constructive comments.
Reference
Forest and Bird 14:23-24.
Research School of Earth Sciences, Victoria University of Wellington
Abstract
A combination of river undercutting and shaking during the 1855 earthquake caused a landslide of Pliocene mudstone and old river gravel/loess cover along the Ruamahanga River, Kopuaranga, northern Wairarapa. The landslide is roughly circular in plan and covers an area of about half a square kilometre. It consists of rotated blocks, swampy areas, hummocky topography and two lakes below a curved crown scarp situated some 100m above the Ruamahanga River. Except for one totara and some dead logs the original native forest was destroyed during the landslide. Growth ring ages indicate a minimum lag time of 30 years for the native forest trees that now colonise about one third of the landside. Breast-height circumferences of 132 trees range from 252cm to 40cm and indicate differences in the growth rate and colonisation history of the various species.
Introduction And Historic Aspects
The 1855 earthquake of January 23rd was the largest earthquake in New Zealand's written history with an isoseismal-estimated magnitude of about M8 (Eiby. 1965). The shock was felt over an area of some 579,000 square kilometres and permanent vertical movement raised about 7,400 square kilometres of the southern part of the North Island. The most visible and violent effects were in and around the Rimutaka Range (Fig. 1A), where about one third of the range was denuded by landslides and a maximum of 2.7m uplift took place at the coast (Lyell, 1868). Horizontal (around 12m dextral) and vertical (from 2 to 0.3m) displacement occurred along the Wairarapa Fault over a length of about 100km (Grapes and Wellman. unpublished data).
An account of the 1855 earthquake faulting along the Wairarapa Fault by Ongley (1943) described landslides, subsidence features, and rents in hilly topography near Palliser Bay, southern Wairarapa, and 79km north of Palliser Bay, a large landslide along the Ruamahanga River less than 1km west of the Wairarapa Fault (Figs. 1A: 2). The landslide was first described by Vennell (1891) who was in the Wairarapa during the earthquake, and relates that a “mountain near Masterton was literally rent in twain, and remains to be seen this day,” An account of the Wairarapa Fault by Iorns (1932) refers to the fact that the landslide blocked the Ruamahanga River and that when the river broke through again “Maoris living in pas lower down (the river) had to climb into trees to save their lives.”
A journey to the upper part of the Wairarapa Valley in November 1953 by
In 1866 the area of the landslide was purchased by Alexander Bruce and this transaction is shown on the Survey Office Plan (1866, s.o. 10799) where a high, steep scarp with a small hill in front of it are described as an “earthquake rent”. The
Figs. 1A, B, C and D.
(A) Map showing the location of the 1855 landslide, Ruamahanga River, Kopuaranga, northern Wairarapa, and the trace of the 1855 earthquake rupture along the Wairarapa Fault. Shaded area of southern part of the Rimutaka Range represents the area of extensive landslide caused by the 1855 earthquake. Dotted area represents Pliocene sediments.
(B) Topgraphic and geomorphic map of the 1855 landslide area, 20 m contour interval, u = upthrown; d = downthrown side of the fault. Arrowed lines along fault indicate direction of horizontal movement. Ground slope between the fault strands is indicated by short arrowed lines.
(C) Geologic map of the 1855 landslide.
(D) Cross section of the 1855 landslide along line A-B in (C).
Topography and Geology
Geomorphic and geologic maps and a cross section of the landslide are shown in Figs. 1B, C and D. The landslide is roughly circular with an area of approximately half a square kilometre. It consists of a number of rotated blocks, swampy depressions, arcuate scarps, hummocky ground (debris flows and mudflows), and two lakes to the west of a single primary failure plane that forms a curved crown scarp 100m above the present day flood plain of the Ruamahanaga River (Fig. 1B; Fig. 2). The primary failure plan is in blue-grey marine mudstone with thin sandstone layers of Late Miocene to early Pliocene age (Late Tongaporutuan-Opoitian) that are capped by 1-4m of river gravels of the Porewan aggradation surface (80-60 kyrs) overlain by about 0.8m of loess (Fig. 1C). The rotated slump blocks of mudstone all have a mean slope angle for their west-facing sides of about 30° and a little less for the east-facing slopes. Swampy areas and the two lakes have formed on the eastern side of the rotated blocks (Fig. 1B and C). The backward (east-facing) tilted slopes of the rotational blocks are covered by a mixture of gravels and loess that is partly weathered to a yellow-grey earth about 0.7m thick with weakly developed A (10 YR 6/4 dry) and B (10 YR 7/4 dry) horizons. The west-facing slopes are composed of a soil (about 0.3m thick), again with weakly developed A (2.4 Y 4.2 dry) and B (5 Y6/1 dry) horizons that overlies mudstone. The thicker soil developed on loess is the same as that exposed along the top of the crown scarp and contrasts with the shallow soil developed on mudstone in the 135 years since the landslide.
Vegetation
The landslide is situated on the western edge of a former forest known as Forty-Mile Bush, which extended north to the junction of the Tauwera and Ruamahanga Rivers. The forest was mainly of totara, karaka, fuchsia, titoki, broadleaf, mahoe, hinau and ribbon-wood while the flat terraces west of the Ruamahanga River were covered by grasses together with short tussock, bracken, manuka and swamp vegetation (Smith, 1853). Smith noted that the southern and eastern slopes of the hill called Rerenga, and the site of the landslide, were covered in “excellent timber”. Today about a third of the landslide is covered with native trees and the rest is in grass and grazed (Fig. 2). It is presumed that the original forest, which occupied
Fig. 2. Aerial photo showing site of 1855 landslide, Ruamahanga River. The trace of the Wairarapa Fault is indicated by the white arrow. (Reproduced with the permission of the Surveyor General. Department of Survey and Land Information).c., 30m, that could represent part of the pre-1855 forest (cf. Table 2). Except for some large, dead tree trunks on the lower part of the landslide, there is no sign of any other original trees and it is probable that they rotted or have been burnt after the slip occurred, i.e. sometime after 1866 when the area was purchased by Alexander Bruce.
Cores taken from 5 living trees (rimu, totara, white pine, beech and rewarewa) give growth ring ages of between about 90 and 100 years (Table 1). These ages indicate a lag-time for the beginning of reforestation of the landslide of between 30 and 40 years. Presumably, the first plans to have colonised the landslide would be such species as Coriaria (tutu), Cassinia and kanuka (e.g. Druce, 1957; Wassilieff, 1986). Growth ring ages of two felled kanuka are 82 and 88+ years suggesting that they are post-burning, second generation specimens. The kanuka are growing on the area of loess and boulders and are mainly situated at the edge of the forest trees and/or in canopy gaps. The average time lag for Melicytus ramiflorus (mahoe) colonisation of avalanche boulder terraces developed on one of the 1855 landslides from the western slope of the Orongorongo Valley, Rimutaka Range, and where there has been no subsequent burning, was estimated at 20 years by Robbins (1958).
Table 2 gives breast-height circumferences for 132 trees that now colonise the landslide and presumably began growing since 30 years after the event. The smaller trunk circumferences of typical understory species such as pigeonwood, red matipo, and lophomyrtus, imply that they began growing after the forest trees had become established. The smallest circumference (and presumably the youngest) kanukas are growing near the forest tree-open grass boundary.
Column A - Number of trees measured; Column B - Breast-height circumference (cm). Multiple trunks for single trees are enclosed in brackets and are averaged as if single trees. The measurements sample about one fifth of the total trees present and are considered to be representative. Nomenclature follows Connor and Edgar (1987).
Conclusion
Reference to the landslide site in 1853 by the Government Surveyor Smith when there was no landslide, and by the Government Geologist Crawford in 1863 when there had been a landslide, make it certain that the landslide took place sometime between November 1853 and February 1863, and almost certainly during the 1855 earthquake. The observatin of Smith in 1853, that the true left bank of the Ruamahanga River was a high cliff, indicates that the landslide probably resulted from a combination of the undercutting of this cliff and earthquake shaking. The similar angle of repose of the large rotated blocks within the landslide implies that all of the blocks slid at the same time and as a result of short-term failure along a single arcuate crown scarp.
It is assumed that the native forest cover mentioned by Smith in 1853 was destroyed during the landslide. Only one living totara and several dead trunks of
Acknowledgements
Many thanks are due to Professor Harold and Mrs Joan Wellman, Mrs Diane Kelly, Janet and Peter Kelly for a pleasant day's outing on the landslide site measuring the circunmferences and identifying the trees.
References
New Zealand Journal of Botany 25:115-170.
Transactions of the New Zealand Institute 2:345-363.
New Zealand Department of Scientific and Industrial Research Bulletin, 124.
New Zealand Journal of Geology and Geophysics 11:630-647.
The Wairarapa Times Age, 24th September 1932.
Principles of Geology, Vol. 2, pp. 82-89. London,
Transactions of the Royal Society of New Zealand. 73:84-89.
Transactions of the Royal Society of New Zealand 85:205-212.
Transactions of the Royal Society of New Zealand. Geology 2:63-78.
Third Report of the Australasian Association for the Advancement of Science 3:531-532.
Journal of the Royal Society of New Zealand 16:229-244.
3rd Edition (revised). Published by the authors, 1987
It is hard to explain exactly what it is about the English naturalist
However there was more to Swainson than this introduction suggests. He was one of those who pioneered the use of lithography for natural history ilustrations, a medium that was cheaper and more flexible than engraving, and he was an accomplished naturalist with a string of species descriptions to his credit. As an author he was prolific, although not always as careful as he should have been. He was a colourful, if sometimes quarrelsome figure, inhabiting a period that constituted the heyday of natural history in Britain.
There were few amateur naturalists living in the Wellington area at the time of Swainson's arrival here, but those that were might have been forgiven for thinking that someone with his background would help nourish and sustain a local forum for natural history. But such hopes, if they existed, were ultimately dashed. There were initially promising signs: his contact with Acheron, the exsiccatum of ferns-but the flicker of interest in natural history matters was virtually extinguished with an intemperate letter to Mantell declining honorary membership of the New Zealand Society. Swainson's energies were largely directed at maintaining himself and his family in a testing environment. Such spare time as was available was spent in executing a large number of sketches of New Zealand bush scenes, mostly in the Wellington district.
We are fortunate, in New Zealand, in having a large amount of Swainson material in public collections or in the hands of his descendant
This privately published work will be a useful addition to an increasing list of Swainson biographies and evaluations of his scientific and personal life, but one shares with the authors their regret in not being able to provide a more attrative setting for all their hard work. The illustrations in particular have suffered from the reprographic process employed, and some are barely discernible. Their more selective use and exclusion from such places as the Sources and Summaries section might have provided a tidier result. It is not clear what the value is of reprinting the working documents from microfiche in a form that is almost illegible; a less cumbersome means of identifying source material could perhaps be found. These, and other idiosyncracies of design can occasionally be disconcerting, but do not detract too greatly from the work as a whole. The authors, in their plight of inadequate publication resources, invite our tolerance. This is gladly given.
J.R.H. Andrews
School of Biological Sciences. Victoria University of Wellington.
Published by Victoria University Press, Wellington, 1988 ($45)
New Zealand's biota attracts a lot of interest. It features prominently in world literature and is the basis for our strong conservation movement. Much is written about the plants and animals but few authors directly confront the question of why the biota is of such interest. This new addition to the prolific natural history literature is an attempt to shed some light on the “story of New Zealand's plants” from this point-of-view. And, very appropriately, it has been done by the former editor of Tuatara for many years. John Dawson has spent his professional life researching certain groups of plants that occur in New Zealand (especially Umbelliferae and Myrtaceae) and has developed undergraduate and postgraduate courses in advanced Botany which explore the origins and special features of our flora. The book has grown from these courses.
It also owes much to New Zealand Plants and their Story which was the first attempt to review the distinctive features of native plants and which is now 60 years out-of-date. John Dawson set out to build very closely on Cockayne's model by reviewing the increase in knowledge gained over the past 60 years. It is not a guide book to plant identification but aims to use a representative selection of the larger and more conspicuous vascular plants to illustrate the special features of our flora.
The book is easy to use and enjoyable to browse. Although we are conditioned to colour illustrations in most modern natural history books, this one's reliance on monochrome photographs certainly does not detract from its purpose. The illustrations are copiously spaced throughout the text and very nicely reproduced with good clarity and tonal range. In fact, several now historic photographs from Cockayne's earlier book are reproduced with greater clarity than the originals. The printing layout gives a remarkably wide outer margin, some might say wasteful, but it is utilised to bring variety to each page with figure captions and photo overlaps. The author's style is straightforward, certainly not exuberant and the text is well referenced.
John Dawson's version of the story of New Zealand plants is organised into 12 Chapters, mainly based on a habitat or community approach. Forests, which dominated the New Zealand landscape prior to the arrival of humans, also dominate the book with 4 chapters devoted to the structural features of the plants themselves (roots, flower forms, leaf features) and their associated vines and epiphytes (“the first thing that strikes the overseas botanist”). Characteristics of the major forest types in New Zealand are reviewed with brief notes on specialised communities such as coastal forest, kauri forest, mangroves and swamps.
A particularly interesting chapter discusses the recent debate over possible causal factors behind the divaricating growth habit of so many low shrubs in this country. These impenetrable twiggy shrubs and juvenile trees are a significant feature of our flora and have been variously attributed to harsh climatic factors or the browsing effect of moas. John Dawson provides an intriguing appraisal of these views which should stimulate the non-specialist reader to take an added interest.
Plants of open habitats are segregated into lowland and alpine. A glimpse of the dynamic, ever-changing patterns of vegetation is given in Chapter 7 where the origins
The section on the alpine flora surveys the main features and highlights some dominant plant types, especially those of scree and rock areas, before considering the strange debate about where the alpine plants came from. I say “strange” because surely most of our plants evolved nowhere else but in New Zealand. The problem is that geologists have told us that New Zealand's present mountains are quite new, only a few million years old and prior to their formation, the land was low-lying for much of its history, with a warmer climate than now. So we are faced with the problem of explaining how a specialised alpine flora, richer in species than the forests, came into being in such a short time. Were the ancestors of the plants already here? Did they reach New Zealand mountains by migrating from Antarctica? Did they get blown here from the mountains of SE Asia, possibly via Australia? A discussion of the views of various authors is presented within a predominantly migrationary framework. Whilst I agree that we cannot rule out the possibility of some immigrants, I must say I prefer Cockayne's whimsical statement, made 61 years earlier, that if the plants could speak “we might learn from some of them that their very remote ancestors were born on New Zealand soil”. In my view, the “alpine problem” will never be resolved by prolonging the discussion of ad hoc explanations, only by adopting a rigorous scientific approach to biogeography.
Two chapters review plants of the outlying islands (subantarctic islands, Chatham, Kermadec, Lord Howe and Norfolk Islands) and comment on the flora of other southern lands. These descriptive accounts focus on genera and species which are of interest to New Zealand. Many readers will be surprised to learn that certain plants are so widely distributed over the islands and lands of the southern oceans and, for example, that tiny Lord Howe Island supports an endemic species of Carmichaelia, the only member of this genus occurring outside New Zealand. The origins and significance of some of these widespread southern plants are discussed in terms of both long-term land continuity and long distance dispersal.
The final chapter, devoted to plant fossils from New Zealand, reveals the wealth of discovery in this field since the time of Cockayne. The botanical history, as told by plant fossils (largely pollen) in New Zealand and its surrounding lands, pieces together a picture very different from today but steadily evolving to the modern pattern. Changes are particularly notable in the distribution of Nothofagus species-groups, the genus Casuarina and the podocarps. In his concluding remarks, John Dawson draws attention to the significance of New Caledonia as a place where the Gondwana biota has survived better than in either Australia (with its aridity) or New Zealand (with its more severe Pleistocene climate), a view with which I agree.
A book which aims to be as comprehensive as this one but is produced with a student budget in mind, cannot fulfil everyone's expectations. Thus, one reviewer has said it leaves untouched the human side of plants, another that it fails to do justice to the functioning and dynamics of plant communities. My own bias is towards historical biogeography so I can add that I would have appreciated more emphasis on recent progress in this field with maps showing evolutionary hypotheses for some of the key plant genera such as Nothofagus. However, John Dawson could never write the perfect book to suit all readers and their particular viewpoints. The fact remains that he has produced a worthy successor to Cockayne's earlier volume
G.W. Gibbs