ACTIVITY OF ARBOREAL LANDHOPPERS (AMPHIPODA: TALITRIDAE) AT HALF WOODY HILL, MELALEUCA A.M.M. Richardson Department of Zoology, University of Tasmania, GPO Box 252C, Hobart, Tasmania 7001 Abstract Comparison of the catch in ground pitfalls and hand samples with that from cups holding moss stapled to tree trunks showed that Austrotroides leptomerus is the only species out of five available landhoppers to be caught above ground in rainforest near Melaleuca. Low capture rates prevented further analysis of the effects of aspect, epiphyte cover or sucker density on the catch. Improvements in design for further studies of the activity of arboreal landhoppers are suggested. INTRODUCTION Most members of the Tasmanian landhopper fauna live in the leaf litter of forest, scrub and sedgeland, but one or two species have unusual habits. Keratroidesalbidus is a specialised burrowing species (Friend 1987a), and Ordiestiella neatnbulans and O. quasimodo prefer waterlogged litter in swamps and at the immediate edges of small streams and seepages (Friend 1987a, Richardson and Swain 1990). Austrotroides leptomerus and A. longicomis both appear to make extensive use of above ground habitats (Friend 1987b, Richardson and Swain 1990), i.e. litter trapped in branch axils, moss on tree trunks and branches, and the leaf axils of Richea pandanifolia. This brief study aimed to compare the activity of landhoppers (as measured by their capture rate in pitfall traps) on the ground and on the trunks of trees, Each author is responsible for the opinions and facts expressed in his or her article— EDITOR. 2 The Tasmanian Naturalist July 1993 Table 1. Characteristics of trees used for trunk traps at Half Woody Hill. Epiphyte spread even indicates evenly spread around the trunk, denser on S indicates denser growth on the south facing side. Tree No. Diameter (m) Epiphyte height Epiphyte spread Suckering density Trap Type i 1.28 3-4cm even sparse up 2 0.86 >4cm denser on S dense down 3 0.87 Keratroides vulgaris >Neorchestiaplidbrancha >M. tasmaniae> Austrotroides leptomerus. In the pitfalls, four spedes appeared; in order of abundance N. plicibrancha > K. imlgaris > M. cryptus = A. leptomerus. There were no statistically significant differences between the relative frequedes of catches in the pitfall and hand samples (X’= 7.8, p = 0.1). The number of animals caught in the trunk traps (11) was too small to allow any detailed analysis of differences between aspeds or up and down traps. DISCUSSION This study is a slight improvement on that of Friend (1987b) which failed to catch any animals in trunk traps at South Cape Bay. However, it is clear that to gain any information on the activity of arboreal amphipods either trapping methods need to be improved, or traps will have to be left for longer periods, or more of them will have to be used. Moeed (1983) used a much more elaborate trap design in his study of arthropod movements on tree trunks in New Zealand. Moeed did succeed in partitioning upward and downward-moving animals, but the data presented here are not extensive enough to draw any conclusions. It may be that the mesh barriers used did not impede the landhoppers' movements significantly. Richardson (1992a) used a similar, simple trap design in a study of arboreal 4 The Tasmanian Naturalist July 1993 Table 2. Numbers of five species of landhoppers caught in trunk traps on ten Nothofagus cunninghamii trees at Half Woody Hill, with the catches in pitfall traps and by hand at their bases. No animals were caught in trunk traps on four of the ten trees. Mysticotalitrus Mysticotalitrus Neorchestia Austrotroides Keratroides Total tasmaniae cryptus plicibrandia leptopmerus vulgaris Tree traps N 0 0 0 3 2 5 S 0 0 0 3 0 3 E 0 0 0 3 0 3 W 0 0 0 0 0 0 Up traps 0 0 0 3 2 5 Down traps 0 0 0 6 0 6 All trunk traps 0 0 0 9 2 11 Ground collections Pitfall 0 1 5 1 3 10 Hand 9 16 10 1 13 49 Total ground 9 17 15 2 16 59 landhoppers in Hawaii, and was able to derive useable data by returning to the traps over a period of several weeks. In the very wet environment of the Hawaiian mountains the moss in the traps did not dry out. However, at Half Woody Hill in February drying was a problem and the trap design might be improved by adding a drip-feed watering system to keep the moss moist. This might also increase the attractiveness of the traps to the landhoppers. Despite the low catches, Austrotroides leptomerus appears to be the dominant (probably the only) spedes moving on trunks at this site, supporting Friend's (1987b) assessment of their preferred habitat. Whether this species spends most of its time above ground, or in the ground litter, remains unclear. It was caught regularly in pitfall traps at Cox Bight in vegetation which had little or no above ground litter or moss (Richardson 1992b), so its arboreal activities do not appear to be obligatory. Mysticotalitrus tasmaniae is known to climb the trunks of eucalypts in wet gullies on Mt. Wellington (R.B. Mawbey, pers. comm.), but this may be related The Tasmanian Naturalist July 1993 5 to feeding rather than colonising litter and moss above the ground. It is possible that other species at Half Woody Hill are climbing the trunks but not entering the "traps", because they seek refuge in the ground litter. The use of sticky traps in conjunction with the present trap design would identify those animals which were climbing to seek food rather than refuge. ACKNOWLEDGEMENTS I am grateful to Maria Moore and Alison Phillips for carrying out the fieldwork in this project. REFERENCES Friend, J. A. (1987a) The terrestrial amphipods (Amphipoda: Talitridae) of Tasmania: systematics and zoogeography. Rec. Aust. Mus., Suppl. 7:1-85. Friend, J. A. (1987b) A survey of the terrestrial amphipod fauna of the Western Tasmania World Heritage Area. Unpublished Report (National Parks & Wildlife Service, Hobart). Moeed, A. (1983) Invertebrate fauna of four tree species in Orongorongo Valley, New Zealand, as revealed by trunk traps. N. Z. J. Ecol. 6:39-53. Richardson, A. M. M. (1992a) The altitudinal distribution of native and alien landhoppers (Amphipoda: Talitridae) in the Ko'olau Range, O'ahu, Hawaiian Islands./. Nat. Hist. 26:339-352. Richardson, A.M.M. (1992b) The distribution of coastal group landhoppers (Amphipoda: Talitridae) related to sea spray at Cox Bight. WEBS report. (Dept, of Parks, Wildlife & Heritage, Hobart). Richardson, A.M.M. and Swain, R. (1990) Freshwater and Terrestrial Crustacea. WEBS report. (Dept, of Parks, Wildlife & Heritage, Hobart). GREAT CRESTED GREBES AT ORIELTON LAGOON AND PITTWATER Leri E. Wall 63 Elphinstone Road, North Hobart, Tasmania 7000 I have been concerned to notice the recent apparent scarcity of great crested grebes Podiceps cristatus at Orielton Lagoon and Pittwater. In earlier years, particularly during winter months, it was quite common to see half-a-dozen or more quite close to the causeway. In case I had got the wrong impression from my irregular visits I asked some other observers who are often in that locality 6 The Tasmanian Naturalist July 1993 what their thoughts on the subject were. They confirmed my impression that crested grebes are very few this year in comparison with past years. The reason for this scarcity seems clear: the water in the south-west comer of the lagoon is highly polluted to an extent I've not known previously. Iunderstand that the effluent from Midway Point Sewerage plant is not filtered before being discharged into Oriel ton Lagoon. There is thus little chance of any improvement in water quality in the lagoon unless better sewerage treatment facilities are installed. Members of the Bird Observers Association of Tasmania have been lobbying for years to have the lagoon and the adjacent Pittwater proclaimed a wildlife reserve, but so far without success. The area is recognized as being of international importance for migratory birds. Given its significance it is deplorable that the authorities are willing to sanction the degradation of the Lagoon. THE LESSER WANDERER BUTTERFLY DANAUS CHRYSSIPUS IN TASMANIA. Peter Brown Department of Parks, Wildlife and Heritage, 134 Macquarie Street, Hobart, Tasmania 7000 On a brief field trip to the north-west of Tasmania on 18/19 January 1993,1 observed five specimens of the vagrant Lesser Wanderer butterfly, Danaus chrysippus, at four different locations (Stanley, Mt. Cameron West, Marrawah and along the Temma road near Arthur River). I was able to examine three of the specimens closely and all looked extremely fresh, almost as if they had just hatched, so much so that my companion Mark Neyland expressed some doubt that they could have crossed Bass Strait. The weather conditions at the time were mild to warm, but, importantly, it followed two days of extreme temperatures on 15/16 January with moderate to strong northerly winds. The Lesser Wanderer is a large butterfly, approximately the same size as the Common Brown, Heteronympha merope. It is caramel brown on the upper surface with a dark, almost black margin, broadest on the outer forewing where there is also a white blotch. The hindwings are paler caramel with a dotted dark brown and white margin. It is not a particularly swift flyer nor does it appear particularly strong on the wing but obviously its looks belie its capabilities for it is able to fly long distances. We did not see any of our specimens land, but one showed some interest in some flowering thistles. The butterfly is known to occur at intervals in Tasmania, but it is never The Tasmanian Naturalist July 1993 7 recorded in any numbers. Despite my long interest in butterflies in Tasmania, these are the first ones I have seen in the State. The late Len Couchman who had a lifelong interest in butterflies and who had been actively collecting in Tasmania for more than 30 years when he wrote Butterflies of Tasmania (Couchman and Couchman 1977) had only seen one specimen on the wing during all that time. Couchman collected his specimen in 1968 at Bronte, and in searching various museum records was able to locate only one previous specimen taken at Zeehan in 1907. In March 1971 five butterflies were reported from Zeehan and in 1974 a keen collector observed three specimens in diferent parts of the State in January and February. In 1975, one was collected on Mt. Anne. The five specimens observed in the far north-western comer of the state indicate that there was probably a considerable influx of this species into Tasmania, and it is likely that they would have radiated out into other parts of the State subsequent to the sightings reported here. REFERENCES Couchman, L.E and Couchman, R. (1977) The Butterflies of Tasmania, pp. 66-96. In The Tasmanian Yearbook No. 11. (AustralianBureau of Statistics, Hobart). ESTUARINE PLATYPUS ACTIVITY Don Hird 17 Union Street, West Hobart, Tasmania 7000 Published records of platypus utilizing estuarine habitats are apparently lacking (Grant 1984). However, Tom Grant (pers. comm.), an expert on platypus, has received verbal reports of such events. The following observations of platypus utilizing estuarine habitats are apparently the most detailed available to date. The information was transmitted to the Mammal Survey Group of the Tasmanian Field Naturalists Club by observers who prefer to keep their identity and the details of the site confidential for fear of disturbance to the animals involved. I have spoken to the observers and believe that the information is reliable. The observations reported here are from an estuary in south-eastern Tasmania. The estuary is fed by a substantial river, with the actual river mouth being more than three km upstream of the report site. The section of the estuary from where these sightings were made is about 600m wide, with the waterway-gradually narrowing upstream to the river mouth. The salinity of the water concerned is 8 The Tasmanian Naturalist July 1993 unknown but is expected to vary seasonally and with other weather and tidal events. The first sighting, in July or August 1990, was of a young female (no spurs being apparent) some 300-400mm long. This animal initially investigated gumboots at a doorway to a dwelling, apparently as a potential nest site, before searching over a quite large land area and eventually returning to the water. Regular sightings, presumably of this same individual,then ensued, often in an area of sea-grass. In February 1991 a dead platypus was seen floating in the estuary. Coincidently, on the same day an echidna, almost drowned, was rescued from a nearby part of the estuary. No further sightings were made to my informant's knowledge until July 1991 when two platypus appeared at the site of the above individual's first landing. This pair have been seen regularly over the fourteen months to the date of this report. Although no burrow has been found, they have been observed regularly in two rest sites amongst the foreshore tussocks. The area in which these observations were made is some four km seaward of a river-dwelling population of platypus. None of the individuals was seen significantly upstream of the general area of where these sightings were reported. It is of interest to note that the individuals reported here were all first observed soon after the first floods of the year. REFERENCES Grant, T.R. (1984) The Platypus. (New South Wales University Press, Sydney). A SWIMMING ECHIDNA? Editors Note: The following item was extracted from the log book in the Lake Nicholls hut in Mt Field National Park. It was written on February 7 1992, and was penned by 'Anthony and Annette'. The observations of an "aquatic echidm " reported in the previous article lend further interest to this item. You're not gunna believe this but you see we were sitting at the lakeside when we saw a funny shaped thing bobbing up and down in the middle of the lake. We watched it for about two hours as it was swept towards us by the wind. It turned out to be an ECHIDNA!! When it reached the shoreline it became wedged between two rocks and couldn't escape. So I lifted one rock (bloody heavy one too) while Annette picked out the poor little echidna. We took him out to the back of the hut and gave him some salami, but all he wanted to do was rest and hide. I