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Pathways to extinction start long before the death of the last individual. However, causes of early stage population declines and the susceptibility of small residual populations to extirpation are typically studied in isolation. Using validated process-explicit models, we disentangle the ecological mechanisms and threats that were integral in the initial decline and later extinction of the woolly mammoth. We show that reconciling ancient DNA data on woolly mammoth population decline with fossil evidence of location and timing of extinction requires process-explicit models with specific demographic and niche constraints, and a constrained synergy of climatic change and human impacts. Validated models needed humans to hasten climate-driven population declines by many millennia, and to allow woolly mammoths to persist in mainland Arctic refugia until the mid-Holocene. Our results show that the role of humans in the extinction dynamics of woolly mammoth began well before the Holocene, exerting lasting effects on the spatial pattern and timing of its range-wide extinction.

1. The effects of climate change on species' ranges have been usually inferred using niche-based models creating bioclimatic envelopes that are projected into geographical space. Here, we apply an ensemble forecasting approach for niche models in the Neotropical grasshopper Tropidacris cristata (Acridoidea: Romaleidae). A novel protocol was used to partition and map the variation in modelled ranges due to niche models, Atmosphere-Ocean Global Circulation Models (AOGCM), and emission scenarios. 2. We used 112 records of T. cristata and four climatic variables to model the species' niche using five niche models, four AOGCMs and two emission scenarios. Combinations of these effects (50 cross-validations for each of the 15 subsets of the environmental variables) were used to estimate and map the occurrence frequencies (EOF) across all analyses. A three-way anova was used to partition and map the sources of variation. 3. The projections for 2080 show that the range edges of the species are likely to remain approximately constant, but shifts in maximum EOF are forecasted. Suitable climatic conditions tend to disappear from central areas of Amazon, although this depends on the AOGCM and the niche model. Most of the variability around the mapped consensus projections came from using distinct niche models and AOGCMs. 4. Although our analyses are restricted to a single species, they provide new conceptual and methodological insights in the application of ensemble forecasting and variance partition approaches to understand the origins of uncertainty in studies assessing species responses to climate change in the tropics

Biogeography aims to understand the temporal and spatial distribution of life on Earth. Biogeographical research is aimed not only at describing where organisms live, at what densities, with whom, and how it all relates to the environmental and geographical setting but also why this is so. The International Biogeography Society, IBS, is a young and vibrant international and interdisciplinary society contributing to the advancement of all studies of the geography of nature, including spatial ecology (). In January 2009, the 4th International Conference of the International Biogeography Society took place in Merida on the Yucatan Peninsula, Mexico. Ecography provided financial support, acting as the sponsor of the Symposium of Extinction Biogeography and contributing to student travel awards. In addition, Ecography was the officially designated journal for publishing some of the many exciting talks and posters presented at the conference. All of the papers in this special issue of Ecography arose from the IBS conference. They have all been subject to external peer review, subsequent revision, and final editorial decisions of acceptance/rejection, Biogeography aims to understand the temporal and spatial distribution of life on Earth. Biogeographical research is aimed not only at describing where organisms live, at what densities, with whom, and how it all relates to the environmental and geographical setting but also why this is so. The International Biogeography Society, IBS, is a young and vibrant international and interdisciplinary society contributing to the advancement of all studies of the geography of nature, including spatial ecology (). In January 2009, the 4th International Conference of the International Biogeography Society took place in Merida on the Yucatan Peninsula, Mexico. Ecography provided financial support, acting as the sponsor of the Symposium of Extinction Biogeography and contributing to student travel awards. In addition, Ecography was the officially designated journal for publishing some of the many exciting talks and posters presented at the conference. All of the papers in this special issue of Ecography arose from the IBS conference. They have all been subject to external peer review, subsequent revision, and final editorial decisions of acceptance/rejection

There is increasing evidence that areas with high concentrations of species tend to have high concentrations of human activities. would this tendency be altered with projected environmental changes? We investigate this possibility using the most extensive available dataset on species distributions in Europe, providing data for 3143 species. Observed land uses were utilised to generate three indicators of anthropogenic 'pressure' for 1971-2000: urbanisation, cropland and grassland use intensities. Storylines describing alternative development pathways were used to create four land-use scenarios for 2021-2050. Exposure of biodiversity to human activities was measured as changes in the degree of pressure recorded in hypothetical reserve networks selected to maximize the representation of plant, breeding bird, mammal, amphibian, and reptile species. In all socio-economic scenarios there was a tendency for increasing urbanisation and decreasing cropland intensities within selected conservation areas. Pressures arising from increasing grassland use were variable across scenarios and taxa. Our results challenge the idea that a single development strategy might provide reduced impacts in all regions and taxonomic groups. We show that impacts are likely to be complex and that tradeoffs might exist among development strategies. Nevertheless, results are contingent on the data, scale, and type of analyses conducted and further research is required to assess the impacts of alternative human-development scenarios. (c) 2007 Elsevier Ltd. All rights reserved.

Udgivelsesdato: 2008, The species-area relationship is one of the strongest empirical generalizations in geographical ecology, yet controversy persists about some important questions concerning its causality and application. Here, using more accurate measures of island surface size for five different island systems, we show that increasing the accuracy of the estimation of area has negligible impact on the fit and form of the species-area relationship, even though our analyses included some of the most topographically diverse island groups in the world. In addition, we show that the inclusion of general measurements of environmental heterogeneity (in the form of the so-called choros model), can substantially improve the descriptive power of models of island species number. We suggest that quantification of other variables, apart from area, that are also critical for the establishment of biodiversity and at the same time have high explanatory power (such as island age, distance, productivity, energy, and environmental heterogeneity), is necessary if we are to build up a more predictive science of species richness variation across island systems