Island country: Aboriginal connections, values and knowledge of the Western Australian Kimberley islands in the context of an island biological survey

Water, land, fire, and forest: Multi-scale determinants of rainforests in the Australian monsoon tropics

The small rainforest fragments found in savanna landscapes are powerful, yet often overlooked, model systems to understand the controls of these contrasting ecosystems. We analyzed the relative effect of climatic variables on rainforest density at a subcontinental level, and employed high-resolution, regional-level analyses to assess the importance of landscape settings and fire activity in determining rainforest density in a frequently burnt Australian savanna landscape. Estimates of rainforest density (ha/km²) across the Northern Territory and Western Australia, derived from preexisting maps, were used to calculate the correlations between rainforest density and climatic variables. A detailed map of the northern Kimberley (Western Australia) rainforests was generated and analyzed to determine the importance of geology and topography in controlling rainforests, and to contrast rainforest density on frequently burnt mainland and nearby islands. In the northwestern Australian, tropics rainforest density was positively correlated with rainfall and moisture index, and negatively correlated with potential evapotranspiration. At a regional scale, rainforests showed preference for complex topographic positions and more fertile geology. Compared with mainland areas, islands had significantly lower fire activity, with no differences between terrain types. They also displayed substantially higher rainforest density, even on level terrain where geomorphological processes do not concentrate nutrients or water. Our multi-scale approach corroborates previous studies that suggest moist climate, infrequent fires, and geology are important stabilizing factors that allow rainforest fragments to persist in savanna landscapes. These factors need to be incorporated in models to predict the future extent of savannas and rainforests under climate change.

Mammals on Western Australian islands: occurrence and preliminary analysis

We present a database of indigenous and non-indigenous terrestrial mammal records on Western Australian (WA) islands, updated from a database we published more than 20 years ago. The database includes records of 88 indigenous species on 155 islands, compared with 54 indigenous species on 141 WA islands in the paper by Abbott and Burbidge in CALMScience, Volume 1, pp. 259–324. The database also provides 266 records of 21 species of non-indigenous mammal species on 138 WA islands, more than double the number of records in the earlier review. Of the 33 threatened and near-threatened WA non-volant mammals, 16 occur naturally (and have persisted) on WA islands, five additional species occur on islands outside WA, 14 successful conservation translocations of 10 species have been undertaken to WA islands, and six species have been successfully translocated to 12 islands outside WA – two of which do not currently occur on WA islands. The house mouse now accounts for the largest number of extant records of non-indigenous species. Even with the increasing number of conservation translocations to mainland islands (fenced exclosures), WA islands remain essential for the effective conservation of several threatened and near-threatened mammals and many of the translocations to mainland islands have been sourced from islands.