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Rapid growth in the digitisation of the world's natural history collections substantially simplifies scientific access to taxonomic and biogeographic information. Despite recent efforts to collate more than two centuries of biodiversity inventories into comprehensive databases, these collections suffer limitations across spatial, temporal and taxonomic dimensions. We assessed taxonomic shortfalls in preserved specimens from 296 plant families native to Australia, for which records have been collated into the Australasian Virtual Herbarium (AVH), specifically addressing the following questions: (1) Based on the number of specimen records per species, which Australian native plant families are under- or over-represented in the collection of preserved specimens digitised in the AVH? (2) To what extent does the distribution of collectors among plant families, or the area occupied by plant families, explain patterns of taxonomic representativeness? We found that the number of preserved specimens per family is not proportional to the family's known species richness. For 29% of Australia's plant families (i.e. 86), the number of digitised records constitutes < 50% of the number expected given species richness within those families. Further, only 34% of families (100) have at least 20 specimens digitised for each species recorded in the AVH. Families occupying small areas (< 200 grid cells) are more likely to be under-represented taxonomically, while there is a strong positive correlation between the number of unique collectors and the extent of taxonomic over-representation. A sound understanding of biodiversity is critical for megadiverse countries such as Australia, and identifying biases in digital inventories may help with establishing future sampling and digitisation strategies to enhance taxonomic representation. [ABSTRACT FROM AUTHOR]

Context: Climate refugia—areas that remain suitable for species during periods of climate disruption—have played an important role in species persistence over time. Identifying and protecting these refugia is a key climate change adaptation approach for conservation planning. Objectives: To identify climate refugia for Australian tropical/sub-tropical rainforest flora, from the Last Glacial Maximum to 2070. Methods: Habitat suitability models were calibrated for 30 species using Maxent, and projected onto climate data for: Last Glacial Maximum (LGM, ~ 22,000 ybp); mid-Holocene (MH, ~ 6000 ybp); current period; and 2070. The intersection of suitable habitat over consecutive periods was assessed, identifying: current refugia (LGM–MH–Current); future refugia (Current–Future); and High Value Refugia (HVR, suitable over all four periods). Refugial hotspots (regions suitable for at least 15 species) were also identified. Results: Suitable habitat was generally projected to span the greatest area in the current period. Four current refugial hotspots were identified: Wet Tropics, Central Mackay Coast, South Eastern Queensland, and North Coast (New South Wales). While suitable habitat for most species may decline in the future, HVRs will likely be retained for all species to at least 2070, although restricted in size. Future refugia was also projected in areas beyond species' dispersal ranges. Conclusions: HVRs are highly important for the conservation of these rainforest species, given their generation times, limited dispersal capabilities and additional anthropogenic barriers to movement. This study assists in understanding long-term spatial shifts in rainforest flora in response to climate change and in designing future conservation strategies. [ABSTRACT FROM AUTHOR]

There is substantial evidence of climate-related shifts to the timing of avian migration. Although spring arrival has generally advanced, variable species responses and geographical biases in data collection make it difficult to generalise patterns. We advance previous studies by using novel multivariate statistical techniques to explore complex relationships between phenological trends, climate indices and species traits. Using 145 datasets for 52 bird species, we assess trends in first arrival date (FAD), last departure date (LDD) and timing of peak abundance at multiple Australian locations. Strong seasonal patterns were found, i.e. spring phenological events were more likely to significantly advance, while significant advances and delays occurred in other seasons. However, across all significant trends, the magnitude of delays exceeded that of advances, particularly for FAD (+22.3 and −9.6 days/decade, respectively). Geographic variations were found, with greater advances in FAD and LDD, in south-eastern Australia than in the north and west. We identified four species clusters that differed with respect to species traits and climate drivers. Species within bird clusters responded in similar ways to local climate variables, particularly the number of raindays and rainfall. The strength of phenological trends was more strongly related to local climate variables than to broad-scale drivers (Southern Oscillation Index), highlighting the importance of precipitation as a driver of movement in Australian birds. [ABSTRACT FROM AUTHOR]

Climate change over the past ~30 years has produced numerous shifts in the distributions and abundances of species and has been implicated in one species-level extinction. Using projections of species' distributions for future climate scenarios, we assess extinction risks for sample regions that cover some 20% of the Earth's terrestrial surface. Exploring three approaches in which the estimated probability of extinction shows a power-law relationship with geographical range size, we predict, on the basis of mid-range climate-warming scenarios for 2050, that 15-37% of species in our sample of regions and taxa will be ‘committed to extinction’. When the average of the three methods and two dispersal scenarios is taken, minimal climate-warming scenarios produce lower projections of species committed to extinction (~18%) than mid-range (~24%) and maximum-change (~35%) scenarios. These estimates show the importance of rapid implementation of technologies to decrease greenhouse gas emissions and strategies for carbon sequestration. [ABSTRACT FROM AUTHOR]

Thomas et al. reply - We reconsider our estimates of climate-related extinction in the light of three questions raised by Thuiller et al., Buckley and Roughgarden and Harte et al.. We are able to confirm our original conclusion that climate change represents a major threat to terrestrial species. [ABSTRACT FROM AUTHOR]