Keeping Australia’s islands free of introduced rodents: the Barrow Island example

Islands are important reservoirs of endemic and threatened species, but anthropogenic influences have impacted their biotas. Australia has over 8000 islands, both continental and oceanic, but because of considerably increased traffic, both tourist and commercial, many of these islands have been and are subject to increased threats from invasive species. The invasive Black Rat Rattus rattus is of particular concern as it can negatively impact mammal, bird, reptile, invertebrate and plant populations. Barrow Island, in northwest Western Australia, is an island requiring particular protection from Black Rats as it is a Class A nature reserve with many unique and threatened taxa that is subject to major disturbances from activities associated with oil extraction and a large liquefied natural gas processing plant. Strict quarantine is currently imposed on all materials and persons being sent to the island and there is an intense on-island surveillance programme. So far the protocols used have prevented Black Rats establishing on this island, but such a level of biosecurity is clearly impossible for all islands. In this paper we discuss the effectiveness of quarantine inspections and surveillance together and alone in protecting high-risk, high-value Australian islands against introduced rodents and we document eradication costs for other islands. World-wide, it has only been possible so far to eradicate rats from relatively small islands, mostly with no non-target indigenous mammals and larger islands only where there are no non-target indigenous mammals. Models based largely on economic considerations have suggested it is more cost effective to use surveillance alone without quarantine for Black Rats on Barrow Island and that if rats become widespread (an estimated 4% risk), it may be more cost effective not to attempt eradication. Such models provide useful guidance for managers where biodiversity values are relatively low or where there are no non-target species, but for Barrow island we argue for continuation of quarantine as well as surveillance and an increased level of quarantine controls at the point of departure on all people, vessels and aircraft visiting other vulnerable Australian islands.

Challenging species delimitation in Collembola: cryptic diversity among common springtails unveiled by DNA barcoding

Collembola is one of the major functional groups in soil as well as a model taxon in numerous disciplines. Therefore the accurate identification of specimens is critical, but could be jeopardised by cases of cryptic diversity. Several populations of six well characterised species of springtails were sequenced using the COI barcode fragment as a contribution to the global Collembola barcoding campaign. Each species showed high intraspecific divergence, comparable to interspecific sequence divergence values observed in previous studies and in 10 congeneric species barcoded here as a reference. The nuclear marker, 28S, confirmed all the intraspecific lineages found with COI, supporting the potential specific status of these entities. The implications of this finding for taxonomy and for disciplines relying on species names, such as evolution and ecology, are discussed.

Changes in vegetation over nine years after rehabilitating a linear feature in Australia's arid zone

A 36-km road built in 1961 between Ayers Rock (Uluru) and the Olgas (Kata Tjuta), Northern Territory, Australia had seriously deteriorated by the 1980s. A newly aligned road, which was ecologically located and avoided sensitive Aboriginal sites, was completed early in 1991. The old road was rehabilitated by deep ripping, filling with imported sand and topsoil and by grading logs and windrows1 over the new surface. This paper reports on the effectiveness of the rehabilitation technique used in reinstating vegetation over 8 years and considers whether this rehabilitation aim was met. Plant colonisation and succession were monitored on 15 paired plots, one in the rehabilitated road and the other in the adjacent undisturbed habitat (with four exceptions) and also on the windrows. Sites at eight creek crossings and those subject to fire and rabbit activity were also monitored. Different landscape units responded in different ways to the rehabilitation. Herbaceous species from imported sand plain fill and top soil eventually dominated the road where they were introduced and were likely to persist in most areas because of local recruitment. The revegetation of the road has stabilised the old road surface as observed by the reduced erosion although succession did not always approach the reference site communities because of a greater resemblance to the Simpson Land System. Over the 8 years of monitoring considerable changes in vegetation occurred and are probably continuing. Only the road sites in the Simpson Land System approached the condition of the adjacent undisturbed vegetation because the vegetation of the other two land systems became closer to that of the Simpson Land System rather than to that of the surrounding vegetation. It is recommended that the introduced Buffel grass, known to alter landscape-level processes by reducing native herbaceous species and increasing risk of high intensity wildfire, which is most evident at creek crossings, should be controlled. Recommendations are made for improved management.

Global Collembola on Deception Island

Three new non-indigenous springtail species are recorded in recent collections made on Deception Island, South Shetland Islands, maritime Antarctic: Deuteraphorura (Deuteraphorura) cebennaria (Gisin) (Collembola: Onychiuridae), Mesaphorura macrochaeta Rusek (Tullbergiidae), and Proisotoma minuta Axelson (Isotomidae). One of these, D. (D.) cebennaria, is described. Additionally, two new indigenous species, Mesaphorura macrochaeta Rusek and Proisotoma minuta Axelson, are also recorded. The total number of Collembola species now known from the island is 14, comprised of eight native species and six non-indigenous species. This number of non-indigenous species recorded at Deception Island compares with only a single non-indigenous springtail recorded at any other maritime or continental Antarctic location. The reason underlying this high level of occurrence of non-indigenous species on Deception Island is likely to be a combination of the island's high level of human visitation and the presence of relatively benign terrestrial habitats associated with areas of geothermal activity. Two of the new records represent species recently assessed as being of the highest risk to become invaders in the less extreme environments of the subantarctic, thereby emphasising the importance and urgency of adopting and applying effective biosecurity measures to protect the unique and vulnerable ecosystems of this region. Also documented are the impacts on the soil fauna of the island from human trampling, which drastically reduced densities of both native and non-indigenous species to 1% of the abundance typical of non-trampled sites.

The potential of Collembola to act as indicators of landscape stress in Australia

Collembola have been used to assess the ecological status of a range of ecosystems in Australia over the last 35 years. The traits that Collembola possess that make them valuable as ecological indicators are listed. Examples of situations where they have been used to measure impacts in mainly agricultural landscapes are described and the contributions the results have made to management for ecological sustainability are noted. Densities of exotic and native species in a variety of ecosystems are provided and a list of genera with exotic species in Australia is given. A protocol for comprehensively surveying Collembola is described and a critique of different methods given.

Southern Hemisphere Springtails: Could Any Have Survived Glaciation of Antarctica?

Throughout the Southern Hemisphere many terrestrial taxa have circum-Antarctic distributions. This pattern is generally attributed to ongoing dispersal (by wind, water, or migrating birds) or relict Gondwanan distributions. Few of these terrestrial taxa have extant representatives in Antarctica, but such taxa would contribute to our understanding of the evolutionary origins of the continental Antarctic fauna. Either these taxa have survived the harsh climate cooling in Antarctica over the last 23 Myr (Gondwanan/vicariance origin) or they have dispersed there more recently (<2 MYA). In this context, we examined mtDNA (COI) sequence variation in Cryptopygus and related extant Antarctic and subantarctic terrestrial springtails (Collembola). Sequence divergence was estimated under a maximum likelihood model (general time reversible+I+Gamma) between individuals from subantarctic islands, Australia, New Zealand, Patagonia, Antarctic Peninsula, and continental Antarctica. Recent dispersal/colonization (<2 MYA) of Cryptopygus species was inferred between some subantarctic islands, and there was a close association between estimated times of divergences based on a molecular clock and proposed geological ages of islands. Most lineages generally grouped according to geographic proximity or by inferred dispersal/colonization pathways. In contrast, the deep divergences found for the four endemic Antarctic species indicate that they represent a continuous chain of descent dating from the break up of Gondwana to the present. We suggest that the diversification of these springtail species (21-11 MYA) in ice-free glacial refugia throughout the Trans-Antarctic Mountains was caused by the glaciation of the Antarctic continent during the middle to late Miocene.

Phylogeography recapitulates topography: very fine-scale local endemism of a saproxylic ‘giant’ springtail at Tallaganda in the Great Dividing Range of south-east Australia

Comparative phylogeography can reveal processes and historical events that shape the biodiversity of species and communities. As part of a comparative research program, the phylogeography of a new, endemic Australian genus and species of log-dependent (saproxylic) collembola was investigated using mitochondrial sequences, allozymes and anonymous single-copy nuclear markers. We found the genetic structure of the species corresponds with five a priori microbiogeographical regions, with population subdivision at various depths owing to palaeoclimatic influences. Closely related mtDNA haplotypes are codistributed within a single region or occur in adjacent regions, nuclear allele frequencies are more similar among more proximate populations, and interpopulation migration is rare. Based on mtDNA divergence, a late Miocene-late Pliocene coalescence is likely. The present-day distribution of genetic diversity seems to have been impacted by three major climatic events: Pliocene cooling and drying (2.5-7 million years before present, Mybp), early Pleistocene wet-dry oscillations (c. 1.2 Mybp) and the more recent glacial-interglacial cycles that have characterized the latter part of the Quaternary (<0.4 Mybp).

Revision of Friesea Species (Collembola: Neanuridae) of Australia and Offshore Islands, with Biogeographical Notes and Key to Species

Seven species of Friesea are recorded here from Australia and its offshore islands and a key and checklist is provided to them. Three of the species, F. neptunia, F. australica and F. florifera, are new and are described here, and one, F. bispinosa Deharveng, from Heard and Macquarie Islands, is a new record for Australia. Earlier records of F. mirabilis Tullberg and F. claviseta Axelson are examined and the seventh species, F. tilbrooki Wise, already recorded from Macquarie Island and Heard Island, is probably a synonym of F. multispinosa Denis from Kerguelen. Records of Friesea sp. cf. claviseta from Pacific islands are also listed. The fauna is divided into biogeographical groups based on morphology as determined by an existing phylogenetic analysis of the genus.

Review of Tasmanian Hanseniella Bagnall (Symphyla : Scutigerellidae)

The genus Hanseniella is recorded for the first time from Tasmania and eight new species, Hanseniella audax, H. insequens, H. conveniens, H. nuda, H. copiosa, H. pluvialis, H. hebes and H. pyrethrata, are described from the State. A key is given to the Tasmanian species in the genus. Tasmaniella Chamberlin, 1920 is relegated into synonymy with Hanseniella.

Hemilobella, a new genus of Lobellini (Collembola : Neanuridae) from Australia and Malaysia with notes on other Australian lobelline genera

A new genus of Lobellini, Hemilobella, is erected for two new species from Tasmania, H. rounsevelli and H. pluvia, and two described species, H. newmani (Womersley) from Western Australia and H. perakensis (Yosii) from Malaysia, the latter two formerly in Lobella and Propeanura respectively. A key is given to the three genera of Lobellini currently known from Australasia and another to the four species of Hemilobella. Australian species of Yuukianura and Paleonura are discussed.

Phradmon, a new genus of Paleonurini (Collembola : Neanuridae) from Australia with a key to the genera from southern regions and notes on Pronura

Phradmon, gen. nov. (Neauridae : Paleonurini) is created for four new species (Phradmon floccosus, sp. nov., Phradmon maralali, sp. nov., Phradmon tasmaniae, sp. nov., and Phradmon trisetosus, sp. nov.), one described species (Paranura australasiae Womersley, 1935) and one described subspecies (Achorutes hirtellus schoetti Womersley, 1935). The last-named is here elevated to a full species, Phradmon schoetii, and Neanura womersleyi Yosii, 1966 is synonymised with it. All species are from Australia. Lobella (Propeanura) australica Yosii, 1966 is transferred to Pronura and a key is given to the 11 genera of the Paleonurini from southern regions.