More than one-third of the terrestrial mammal species of the central deserts of Australia have vanished in the past 50 years. Few of these have been the subject of even preliminary scientific study, and data as basic as geographic range and preferred habitat are lacking for many species. Aborigines, many of whom lived traditionally in the central deserts until recently, still retain a profound knowledge of the mammals, but this knowledge, too, is fast disappearing. Aboriginal people living in communities scattered through and around the edges of the 1645 000 km2 of the study area, comprising the Great Sandy, Little Sandy, Tanami, Gibson and Great Victoria Deserts and the Central Ranges district, were shown museum skins and asked to provide information about local names, current and past status, and aspects of biology and ecology. Most species, including some thought to have become extinct early this century, persisted in the deserts until 30–50 years ago. New data are presented on former distribution and on the biology and ecology of many species. The mammal fauna of the central deserts was richer and more widespread than generally believed, but the area has suffered a massive and sudden loss of species, probably unparalleled in extent elsewhere in Australia.

Funding for species conservation is insufficient to meet the current challenges facing global biodiversity, yet many programs use expensive single-species recovery actions and neglect broader management that addresses threatening processes. Arid Australia has the world's worst modern mammalian extinction record, largely attributable to competition from introduced herbivores, particularly European rabbits (Oryctolagus cuniculus) and predation by feral cats (Felis catus) and foxes (Vulpes vulpes). The biological control agent rabbit hemorrhagic disease virus (RHDV) was introduced to Australia in 1995 and resulted in dramatic, widespread rabbit suppression. We compared the area of occupancy and extent of occurrence of 4 extant species of small mammals before and after RHDV outbreak, relative to rainfall, sampling effort, and rabbit and predator populations. Despite low rainfall during the first 14 years after RHDV, 2 native rodents listed by the International Union for Conservation of Nature (IUCN), the dusky hopping-mouse (Notomys fuscus) and plains mouse (Pseudomys australis), increased their extent of occurrence by 241-365%. A threatened marsupial micropredator, the crest-tailed mulgara (Dasycercus cristicauda), underwent a 70-fold increase in extent of occurrence and a 20-fold increase in area of occupancy. Both bottom-up and top-down trophic effects were attributed to RHDV, namely decreased competition for food resources and declines in rabbit-dependent predators. Based on these sustained increases, these 3 previously threatened species now qualify for threat-category downgrading on the IUCN Red List. These recoveries are on a scale rarely documented in mammals and give impetus to programs aimed at targeted use of RHDV in Australia, rather than simply employing top-down threat-based management of arid ecosystems. Conservation programs that take big-picture approaches to addressing threatening processes over large spatial scales should be prioritized to maximize return from scarce conservation funding. Further, these should be coupled with long-term ecological monitoring, a critical tool in detecting and understanding complex ecosystem change.

Fluctuations in the composition and abundance of a small-mammal assemblage were studied in a hummock grassland dominated by Plectrachne schinzii at Watarrka National Park from 1988 to 1993. During this period an experiment was conducted to examine the short-term effects of fire on the rodents. We caught three species of rodent (Pseudomys hermannsburgensis, Notomys alexis and Mus domesticus). All species reached their greatest density in spring 1989 during an exceptionally wet period that extended from mid- 1988 to 1990. P. hermannsburgensis was the most abundant species and showed a 10-fold fluctuation in numbers over the sample period; N. alexis was the next most abundant species and showed a 5-fold increase but the population took longer to decline. M. domesticus was recorded only during the period of high rainfall. The number of M. domesticus was significantly less on the burnt plots than on the unburnt plots. Neither P. hermannsburgensis nor N. alexis showed significant differences between burnt and unburnt plots. This study illustrates the impact of rainfall events on the composition and density of small-mammal populations in spinifex grasslands in central Australia. Our results lead to the prediction that rodent populations will achieve densities in the order of 10 individuals ha-' or more in regions that experience three consecutive 6-month periods each with rainfall at 150% of the long-term average. This sequence apparently needs to follow a dry period where rainfall is no more than 85% of the long-term annual average for two consecutive 12-month periods.

Environmental research is often conducted independently of the community in which the environment is situated, with transfer of results into policy and on-ground action occurring independently of the community's interests or aspirations. Increasingly the need for greater community involvement in the research process has been recognized. For community members, however, such engagement usually involves trade-offs. While it is often assumed that community members should participate voluntarily because they will gain from the research, any benefits from knowledge, understanding and a capacity to influence the research have to be offset against time and potential loss of unremunerated intellectual property. We argue, using case studies from tropical Australia and Africa, that a more effective means of engagement and knowledge transfer is training and remuneration of community members as coresearchers. This engagement is much more than payment for labor-it is investment in local intellectual property and requires researcher humility, power-sharing and recognition that access to research funding provides no moral or intellectual authority. Further, we argue that, for effective adoption of research results, community members need to be part of negotiated agreements on the initial nature of the research to ensure it answers questions of genuine local relevance and that local researchers have the capacity to place locally conducted research into a wider context. We argue that immediate rewards for involvement not only secure engagement but, where appropriate, are likely to lead to effective implementation of research results, enhanced local capacity and greater equity in intellectual power-sharing.

The distribution of the bilby Macrotis lagotis was assessed in the Tanami Desert using stratified random plots, repetitively sampled transects, aerial survey transects, and ground truth plots. Compared to a previous assessment of distribution, the extent of occurrence has changed little in the last 20 yr. However, the area of occupancy is small relative to the extent of occurrence and <25% of the current geographic range has bilby sign <20 km apart. Generalised linear modelling was used to determine the strength of association between bilby occurrence and habitat variables and identify refugia characteristics. Four competing candidate models were examined to determine whether bilby occurrence associated significantly with productive substrates and introduced herbivores, the distribution of key predator species, the pattern of fire, and climatic gradients including rainfall and temperature. For the entire study area, bilby presence associated most strongly with variables of mean annual rainfall, substrate type and the probability of dingo occurrence. Proximity to recently burnt habitat formed a significant predictor of bilby occurrence in a model derived for a reduced part of the study area where most sign was found. The work suggested that the current frameworks underpinning understanding of biotic distributions in arid Australia are deficient, and that climatic gradients, lateritic and rocky systems, and predators need to be incorporated into our thinking in the future. The extent of occurrence based on outlier records from opportunistic reports provided a misleading indication of the true status of the bilby.

Australian deserts are characterised by highly patterned plant productivity and an extremely unpredictable climate. The Tanami Desert in central Australia is dominated by vast sandplains interspersed with more productive habitats such as palaeodrainage lines. During 1996 and 1997 fauna surveys were conducted in two areas of the Tanami Desert to investigate the relative importance of palaeodrainage habitat for fauna under different seasonal conditions. The two areas were at latitudes separated by approximately 400 km, and during the study period the northern study area (Tennant) received considerably more rainfall than the southern study area (Kintore). The species richness and abundance of a range of taxonomic groups were compared between the two study areas and between palaeodrainage habitat and adjacent sandplain habitat. The only significant difference between habitats was that small reptiles were more abundant in sandplain than palaeodrainage habitat. Overall, bilbies, bustards and macropods were significantly more abundant at Tennant than Kintore, but significantly more small mammals were captured at Kintore. In both habitats and areas, capture rates, track counts and species richness of reptiles varied significantly with season. The biomass of invertebrates captured also showed significant temporal fluctuations. Burrowing frogs were active only after rain, and birds showed significant fluctuations in abundance and species richness associated with rainfall. The abundance of small mammals did not vary significantly during this study. Overall, local seasonal conditions were generally more important determinants of the abundance of fauna in the spinifex grasslands of central Australia than was habitat type.

Eighteen non-marine mammal species (including seven species of bats) were recorded from a total of 49 islands in the Wessel and English Company island chains off north-eastern Arnhem Land, Northern Territory. Most individual species were restricted to, or had higher incidence on, larger islands, and species richness as a whole increased as island size increased. The most notable exception was the semi-aquatic Hydromys chrysogaster, which occurred relatively equitably across island sizes; this species, two bat species and the macropod Petrogale brachyotis were recorded from islands smaller than 10 ha. However, the variation between islands in the number of native terrestrial mammal species was not best predicted by island size, but rather by a combination of sampling effort and altitude (which explained 64% of the deviance in species richness), or altitude and distance to larger land mass (explaining 63% of deviance). Richness–area patterns for individual islands in these chains were reasonably consistent with those of other islands sampled in northern Australia. However, the fauna of the Wessel and English Company groups as a whole was less rich than that of the Pellew and Kimberley islands, and individual islands appeared to have lower species richness than comparable mainland areas. Species that were notably absent or that were recorded from relatively few islands include large macropods, Tachyglossus aculeatus, Antechinus bellus, Phascogale tapoatafa, Sminthopsis spp., Mesembriomys gouldii, Rattus colletti, Leggadina lakedownensis and Pseudomys calabyi. Some of these species may be absent through lack of suitable habitat; others have presumably disappeared since isolation, possibly due to Aboriginal hunting. Richness at the quadrat (50 × 50 m) scale was generally very low. Habitat relationships are described for the 7 species recorded from more than 5 quadrats. At a quadrat-scale, the richness of native mammals was greater on islands larger than 1000 ha than on islands smaller than 1000 ha. Quadrat-scale species richness varied significantly among the islands sampled by the most quadrats (even when the comparison was restricted to either of the two most extensive vegetation types), but this variation was not closely related to either area or altitude. The two most frequently recorded species, the rodents Melomys burtoni and Zyzomys argurus, showed distinct habitat segregation on islands where both were present, but tended to expand their habitat range on islands where only one of the species occurred. The most notable conservation feature of the mammal fauna of the Wessel and English Company Islands is the occurrence of the golden bandicoot, Isoodon auratus, a vulnerable species apparently now extinct on the Northern Territory mainland. Four feral animal species (Rattus rattus, Canis familiaris, Bubalus bubalis and Capra hircus) were recorded from a total of 6 islands.

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