for providing expert advice during the post-workshop review stage. We thank the experts involved in the New Guinea assessment workshop, for their information on species with distributions spanning Torres

Australia hosts approximately 10% of the world's reptile species, the largest number of any country. Despite this and evidence of widespread decline, the first comprehensive assessment of the conservation status of Australian terrestrial squamates (snakes and lizards) was undertaken only recently. Here we apply structured expert elicitation to the 60 species assessed to be in the highest IUCN threat categories to estimate their probability of extinction by 2040. We also assessed the probability of successful reintroduction for two Extinct in the Wild (EW) Christmas Island species with trial reintroductions underway. Collation and analysis of expert opinion indicated that six species are at high risk (.50%) of becoming extinct within the next 20 years, and up to 11 species could be lost within this timeframe unless management improves. The consensus among experts was that neither of the EW species were likely to persist outside of small fenced areas without a significant increase in resources for intense threat management. The 20 most imperilled species are all restricted in range, with three occurring only on islands. The others are endemic to a single state, with 55% occurring in Queensland. Invasive species (notably weeds and introduced predators) were the most prevalent threats, followed by agriculture, natural system modifications (primarily fire) and climate change. Increased resourcing and management intervention are urgently needed to avert the impending extinction of Australia's imperilled terrestrial reptiles.

Documenting the range size and range boundaries of species, and understanding the factors determining changes in these spatial components, is crucial given current rates of anthropogenic climate change and habitat loss. Here, we document the establishment of the acraeine butterfly, Acraea terpsicore, in South‐East Asia (Indonesian islands south of Malay Peninsula, and Timor) and Australia for the first time. We estimate its rate of colonisation and potential for further range expansion in the Indo‐Australian region according to bioclimatic niche models. We modelled the potential distribution of the species in the Indo‐Australian region under current climatic conditions and in 2050 following climate change. The bioclimatic niche models were based on five different modelling techniques, three global circulation models (GCMs) and two CO2 emission scenarios (SRES), yielding 30 individual models that were combined in a consensus model. Acraea terpsicore became established in Indo‐China (Thailand) during the 1980s and since that time it has spread to other parts of South‐East Asia. It was first recorded on the Australian mainland in the Northern Territory in April 2012 and within a few months of detection was found to occur at six locations, with an estimated extent of occurrence of 4000 km2. Thus, the range size of A. terpsicore has expanded by approximately 6000 km across the equator (c. 32 degrees latitude) in 28 years, with an average rate of colonisation (from Thailand to Australia) of 200 km year−1 (range: 170–230 km year−1). The bioclimatic niche models identified additional regions with favourable climatic conditions, and within Australia it is likely to occupy coastal and subcoastal savannah woodlands of the entire monsoon tropics, indicating potential for further range expansion. Moreover, the species' potential range is likely to increase with climate change. We hypothesise that habitat modification, particularly rapid deforestation of tropical forest in South‐East during the past three decades, is a major factor accounting for the range expansion given the species' habitat preference for disturbed and open degraded areas. Climate change may be a contributing factor but is unlikely the sole determinant given the spatial area involved and rate of spread.

The diversity and abundance of native invertebrates is declining globally, which could have significant consequences for ecosystem functioning. Declines are likely to be at least as severe as those observed for vertebrates, although often are difficult to quantify due to a lack of historic baseline data and limited monitoring effort. The Lepidoptera are well studied in Australia compared with other invertebrates, so we know that some species are imperilled or declining. Despite this, few butterfly taxa are explicitly listed for protection by legislation. Here we aim to identify the butterfly taxa that would most benefit from listing by determining the Australian butterflies at most immediate risk of extinction. We also identify the research and management actions needed to retain them. For 26 taxa identified by experts and various conservation schedules, we used structured expert elicitation to estimate the probability of extinction within 20 years (i.e. by 2040) and to identify key threatening processes, priority research and management needs. Collation and analysis of expert opinion indicated that one taxon, the laced fritillary (Argynnis hyperbius inconstans), is particularly imperilled, and that four taxa (Jalmenus eubulus, Jalmenus aridus, Hypochrysops piceatus and Oreisplanus munionga larana) have a moderate–high (>30%) risk of extinction by 2040. Mapped distributions of the 26 butterflies revealed that most are endemic to a single state or territory, and that many occupy narrow ranges. Inappropriate fire regimes, habitat loss and fragmentation (through agricultural practices), invasive species (mostly through habitat degradation caused by weeds and rabbits) and climate change were the most prevalent threats affecting the taxa considered. Increased resourcing and management intervention will be required to prevent these extinctions. We provide specific recommendations for averting such losses.