Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species’ threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project – and avert – future declines. We describe and assess a new database of more than 1.6 million samples from 78 countries representing over 28,000 species, collated from existing spatial comparisons of local-scale biodiversity exposed to different intensities and types of anthropogenic pressures, from terrestrial sites around the world. The database contains measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35) biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains more than 1% of the total number of all species described, and more than 1% of the described species within many taxonomic groups – including flowering plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans and hymenopterans. The dataset, which is still being added to, is therefore already considerably larger and more representative than those used by previous quantitative models of biodiversity trends and responses. The database is being assembled as part of the PREDICTS project (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems – http://www.predicts.org.uk). We make site-level summary data available alongside this article. The full database will be publicly available in 2015.
The 2019–2020 megafires in Australia brought a tragic loss of human life and the most dramatic loss of habitat for threatened species and devastation of ecological communities in postcolonial history. What must be done now to keep impacted species from extinction? What can be done to avoid a repeat of the impacts of such devastating bushfires? Here, we describe hard-won lessons that may also be of global relevance.
Aim (a) To characterize the riparian bird assemblage, and its variation, in a large area of northern Australia; (b) to examine the distinctiveness of this assemblage in relation to the broader landscape; (c) to consider the influence of disturbance on this assemblage; (d) to examine temporal variability in the riparian assemblage, and especially evidence for seasonal movements between riparian and non-riparian areas.Location c. 620,000 km 2 of the seasonal tropics of the Northern Territory, Australia.Methods (a) Synchronous sampling of birds in riparian and adjacent non-riparian areas at 100 sites stratified across 13 catchments and an extensive rainfall gradient. (b) Repeat visits to 13 of these sites at contrasting seasons. (c) Analysis of a larger distributional database to assess the relative occurrence of records in riparian areas relative to nonriparian areas.Results Species richness and the total abundance of birds was significantly greater in riparian zones than in matched non-riparian areas, especially where the riparian zones contained extensive cover of rain forest plants and Melaleuca . Similarity in bird species composition between riparian zones and adjacent non-riparian areas was generally low, and this distinction was greatest in lower reaches of the rivers and where the riparian zone contained no eucalypts. Bird species composition varied gradationally from riparian zones in high rainfall areas, through riparian zones in low rainfall areas and non-riparian zones in high rainfall areas, to non-riparian zones in low rainfall areas. Many species occurred widely across the riparian sites sampled. Of ninety-four species recorded from more than five sites, forty-five species were significantly more abundant in riparian zones than in matched non-riparian zones, whereas this pattern was reversed for only twelve species. There was little association between foraging group and preference for riparian zones. Species had highly idiosyncratic distributions across the riparian samples, with the most common trend being an association with mean annual rainfall. Many species were significantly more closely associated with riparian zones in lower rainfall areas than in higher rainfall areas. Indeed, many species typical of higher rainfall areas extended into lower rainfall areas only, or mainly, along riparian strips. There was some temporal fluidity in bird species composition of riparian zones, suggesting seasonal movements between riparian zones and the surrounding landscape. There was little evidence that disturbance was a major factor influencing the distribution of riparian birds, probably because other major geographical and environmental gradients probably dwarfed the influence of the relatively minor variation between samples in disturbance.
Main conclusionsThe bird fauna of riparian areas is distinct from that of the surrounding savannas, and especially so in lower rainfall areas. Riparian vegetation allows many species to extend their distributions into lower rainfall areas. The riparian assemblage is l...
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