Assessing the vulnerability of species richness to anthropogenic climate change in a biodiversity hotspot. Midgley, G. F.; Hannah, L.; Millar, D.; Rutherford, M. C.; Powrie, L. W..
Global Ecology and Biogeography:
2002
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Aim to compare theoretical approaches towards estimating risks of plant species loss to anthropogenic climate change impacts in a biodiversity hotspot, and to develop a practical method to detect signs of climate change impacts on natural populations. Location The Fynbos biome of South Africa, within the Cape Floristic Kingdom. Methods Bioclimatic modelling was used to identify environmental limits for vegetation at both biome and species scale. For the biome as a whole, and for 330 species of the endemic family Proteaceae, tolerance limits were determined for five temperature and water availability-related parameters assumed critical for plant survival. Climate scenarios for 2050 generated by the general circulation models HadCM2 and CSM were interpolated for the region. Geographic Information Systems-based methods were used to map current and future modelled ranges of the biome and 330 selected species. In the biome-based approach, predictions of biome a real loss were overlayed with species richness data for the family Proteaceae to estimate extinction risk. In the species-based approach, predictions of range dislocation (no overlap between current range and future projected range) were used as an indicator of extinction risk. A method of identifying local populations imminently threatened b! Results A loss of Fynbos biome area of between 51% and 65% is projected by 2050 (depending on the climate scenario used), and roughly 10% of the endemic Proteaceae have ranges restricted to the area lost. Species range projections suggest that a third could suffer complete range dislocation by 2050, and only 5% could retain more than two thirds of their range. Projected changes to individual species ranges could be sufficient to detect climate change impacts within ten years. Main conclusions The biome-level approach appears to underestimate the risk of species diversity loss from climate change impacts in the Fynbos Biome because many narrow range endemics suffer range dislocation throughout the biome, and not only in areas identified as biome contractions. We suggest that targeted vulnerable species could be monitored both for early warning signs of climate change and as empirical tests of predictions.
Towards European climate risk surfaces: the extent and distribution of analogous and non-analogous climates 1931–2100. Ralf Ohlemüller, Emmanuel S. Gritti, Martin T. Sykes, Chris D. Thomas.
Global Ecology and Biogeography:
2006
DOI: 10.1111/j.1566-822x.2006.00245.x
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Aim: Climate is an important determinant of species distributions. We assess different aspects of risk arising from future climate change by quantifying changes in the spatial distribution of future climatic conditions compared with the recent past Location Europe. Methods resolution gridded data set of five climate variables was used to calculate expected changes to the area, distance and direction of 1931–60 climatic conditions under the HadCM3 climate model for four future climate scenarios based on different rates of greenhouse gas emissions (SRES scenarios). Three levels of tolerance ranges determined the thresholds for which future conditions are considered analogous to 1931–60 (pre-warming) conditions. Results For many parts of Europe, areas with pre-warming analogous climate conditions will be smaller and further away in the future than they are now. For any location in Europe, areas with pre-warming analogous mean annual temperature conditions will, on average, be reduced between 23.7% (B1 scenario) and 49.7% (A1FI scenario) by 2100 when assuming a medium tolerance range. The mean distance to these areas will, on average, increase between 272 km (B1) and 645 km (A1FI). These changes are more pronounced for temperature than for water availability variables and also for narrow tolerance ranges compared to wide tolerance ranges. Using a combined measure of both temperature and precipitation variables, areas with prewarming analogous conditions are predicted to be in a more northeasterly direction in the future, but there are considerable regional differences within Europe. Main conclusions The results suggest that, for some parts of Europe, the loss of area with any suitable climatic conditions represents the greatest risk to biodiversity, but in other regions the distances that species may have to move to reach suitable climatic conditions may be a greater problem. Quantifying the distance and direction in analyses of change of climatically suitable areas can add additional information for climate change isk assessments.
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