Penelope Greenslade

Collembola of sub-Antarctic South Georgia

Abstract Qualitative samples of Collembola were obtained from a range of substrates near Husvik, Stromness Bay, South Georgia, between January and March 1996. Collections made at Hope Point near Grytviken (Cumberland East Bay) in 1980/1982 and 1997 were also examined. Fifteen species of Collembola were recorded around Husvik; most were widely distributed. Two of these, Friesia sp. nov. and Cryptopygus badasa, represent additions to the previously recognised fauna of 17 species. A new record of an introduced species, Hypogastrura purpurescens, was identified in collections from Hope Point in 1980/1982, bringing the total South Georgian fauna to 20 species. A key to South Georgian Collembola is included. H. purpurescens and the congeneric Hypogastrura viatica, both cosmopolitan invasive species, have also been recognised on other sub-Antarctic islands and have displaced resident species from some habitats. Their presence on South Georgia, and the dominance of H. viatica in some habitats, highlight the importance of strict quarantine measures to avoid the introduction of further alien invertebrates.

The terrestrial micro-arthropod fauna of the South Sandwich Islands

The South Sandwich Islands are an isolated maritime Antarctic volcanic island arc 550-600km south-east of South Georgia. The terrestrial biology of the islands, with emphasis on the unique habitats associated with volcanically warmed ground, was investigated in 1997 and compared with the data collected during the only previous (1964) terrestrial expedition to the archipelago. The terrestrial fauna includes 29 free-living micro-arthropod species (nine Collembola and 20 Acari) and two, currently unidentified, enchytraeid worms; a further eight parasitic and sublittoral Acari are recorded in the literature. Freshwater habitats are very restricted in the archipelago and no freshwater fauna was located. Supralittoral pools on a single island contained the marine isopod Cassidinopsis maculata. There are no endemic taxa and no shoreline invertebrates other than the supralittoral Archisotoma brucei (Collembola) and two Enchytraeidae. Diversity on individual islands is, in part, a function of available ice-free ground area. The majority of dominant species throughout the archipelago, Cryptopygus antarcticus (Collembola), Nanorchestes nivalis, Eupodes minutus, Alaskozetes antarcticus and Halozetes belgicae (Acarina), originate on other maritime Antarctic islands, while Ayersacarus tilbrooki (Acarina) is sub-Antarctic. Few (one to three) individuals of several other sub-Antarctic species were recorded by either 1964 or 1997 expeditions, but only Pilellus rykei (Acarina) was reported by both. None of the sub-Antarctic species thought to be associated with geothermally warmed ground in 1964 was confirmed in 1997, despite extensive sampling of the same sites. It is more probable that sub-Antarctic colonists frequently arrive on the South Sandwich Islands but are unable to establish longterm viable populations. Cryptopygus caecus, now widespread on Candlemas I., is a solitary exception to this generalization.

Conserving invertebrate diversity in agricultural, forestry and natural ecosystems in Australia

Abstract Continental Australia and Tasmania cover a wide range of latitudes from tropical regions in the north through the arid and semi-arid core to cool temperature regions further south. Vegetation is equally varied and because of this and the continents isolation during the Tertiary, floral and faunal diversity and endemism are very high. Europeans arrived 200 years ago and since that time have markedly modified the landscape by clearing and changing the vegetation, predominantly for agricultural and urban development. Both accidental and deliberate introductions of stock, weeds, crops, trees and pasture plants have also caused enormous changes to Australian environments. In the last few years the deleterious effects of some of these changes have been relaised, for example the extent of soil degradation. Measures are being taken to rectify problems and techniques are being introduced which benefit both primary producers and other users of the land and also nature conservation. Some of these measures for a more sustainable use of the land are illustrated here for four vegetation types, eucalypt woodland, native forests, grasslands and arid systems. They include adopting native tree species for timber production and native grasses for pasture, retention of native vegetation and paying attention to conservation of invertebrates in Parks and Reserves.

Some relations of the meat ant, Iridomyrmex purpureus (hymenoptera: formicidae) with soil in South Australia

Abstract Iridomyrmex purpureus F. Smith is common in southern Australia and nests in conspicuous. often gravel-covered mounds. The effects of the ant on some properties of soil in its nests, and the effects of soil type on the distribution of the ant were studied by comparing the distribution of particle sizes in soil of nests and undisturbed soil profiles. Particle size analysis was used also to determine the relationships of nests and more or less truncated profiles on a naturally eroding, lateritic podzolic soil. Nests are constructed by excavation of gallery systems in the upper part of the profile, with a few shafts extending downwards for 1 metre or more. Excavated material is incorporated in the mound which is usually composed of soil from the A horizon with additions from the B horizon and imported gravel. The density and rate of turnover of nests both appear to he too low for I. purpureus to have any significance to pedogenesis. But soil texture and consistency do influence the distribution of the ant. for nests are not constructed in sands or in very loose, structureless soils. Examination of the distribution of particle sizes in material from nests on the lateritic podzolic soil suggests that establishment of some existing mounds may have pre-dated erosion which has, subsequently, removed more than 20 cm of A horizon. The erosion process would probably require at least hundreds of years, and. if the interpretation of these nests is correct, suggests that they are very old. This is not inconsistent with other observations on rates of change in this population of I. purpurens.

The terrestrial arthropod fauna of the Byers Peninsula, Livingston Island, South Shetland Islands – Collembola

Abstractu2002As an addendum to a recent publication on the terrestrial arthropod fauna of the Byers Peninsula Site of Special Scientific Interest (SSSI), which included preliminary identification of four Collembola, we now present detailed information on Collembola occurring within the SSSI. Five species were recorded [Friesea grisea (Schaffer), Tullbergia mixta Wahlgren, Isotoma (Folsomotoma) octooculata (Willem), Cyptopygus antarcticus Willem, and Cryptopygus sp. nov.]. Species occurrence and abundance differed between samples collected from poorly vegetated stony ground and vegetation cores. F. grisea was both the commonest (58% of individuals) and the most widely distributed (18/19 samples) springtail in the former habitat. Cryptopygus sp. nov. was recorded only in the vegetation core samples. All five species were more evenly distributed in vegetation samples, although C. antarcticus and Cryptopygus sp. nov. were again the least abundant. A list of the terrestrial arthropods of the SSSI is presented.

The invertebrates of sub-Antarctic Bishop Island

Abstract We report on the first comprehensive collection of invertebrates made on sub-Antarctic Bishop Island, which lies 33 km south of Macquarie Island. A total of 15 species were collected, of which 14 also occur amongst the 168 species recorded from Macquarie Island. We hypothesise that the greater species richness of Macquarie Island relative to Bishop Island is largely caused by the greater habitat diversity on Macquarie Island but that other factors, including accidentally introduced species, may also be important.

Cuticle structure and habitat in the Nanorchestidae (Acari: Prostigmata)

Mites of the cosmopolitan family Nanorchestidae may numerically dominate soil faunas of both hot and cold deserts. The genera Nanorchestes and Speleorchestes differ in their distributions with the former more abundant in cold and the latter in hot regions. We suggest that this is related to differences in cuticular structure in the two genera. The cuticle of Nanorchestes spp. is elaborated with regularly spaced granulations which are absent from Speleorchestes spp. These granulations retain a layer of air over the body which may facilitate cuticular respiration in polar soils that are seasonally waterlogged and increase chances of survival by reducing freezing through direct contact with ice. We discuss the biology of the two genera in terms of the ecological strategies that are selected in hot and cold deserts.

Tasphorura, a new genus of Tullbergiinae (Collembola: Onychiuridae) abundant in Tasmanian Nothofagus forest

Abstract. Tasphorura, a new genus of onychiurid Collembola, is erected for an unusually coloured species, Tasphorura vesiculata n.sp., found at a single locality in Tasmanian Nothofagus rainforest. Its isolated phyletic position is noted and extremely high densities are recorded. The conservation implications of the restricted distribution shown by this species, which is typical of many rainforest invertebrates, are discussed with reference to increasing utilization and fragmentation of these forests.

A new diagnosis for Dinaphorura (Collembola: Onychiuridae: Tullbergiinae) and description of new species from Australia

Dinaphorura tooheyensis n. sp., the fourth species of Dinaphorura recorded from Australia, is described from Toohey Forest, a eucalypt woodland, in southeast Queensland. The new species differs from existing species in the genus in that it possesses only a single spiniform process on abdomen VI instead of the usual five or seven and the generic diagnosis has been modified accordingly. Ecological notes on D. tooheyensis are provided as well as a check list and key to species in Dinaphorura.