Known occurrences and modelled distribution and sympatry between Vultur gryphus and Coragyps atratus

Climate change can cause geographic displacement of the ecological niche of a species, so that similar species that previously did not coexist could begin to face new interactions such as competition. Such geographic displacement and increased competition can also be exacerbated by anthropic intervention. Until less than 100 years ago Vultur gryphus and Coragyps atratus did not coexist. Nowadays, possibly as a result of climate change, changes in the distributions of both species created areas where they are now sympatric. Through ecological niche modeling, we evaluated the possible effects that future scenarios of climate change and human influence would have on the distribution and sympatry between the two species. Our models predict that the current distribution of V. gryphus will be reduced between 18% and 24% by 2050 and between 21% and 32% by 2070. Additionally they predict that the distribution of C. atratus will be reduced from 31% to 52% by the year 2050 and from 15% to 60% by 2070. The two algorithms predict a reduction in the areas of sympatry. However, for the northern Andes (where V. gryphus is highly threatened) the overlap percentages between the two species will increase, reaching up to 70% in the year 2070. The distribution of C. atratus will move towards higher areas in the altitudinal gradient, and this will generate an increase in the current sympatry between both species. No clear trend was observed on the effect of human influences on the areas of overlap between the scenarios evaluated. However, the intermediate emissions model of higher urbanization scenario showed higher percentages of moderate and high influences. The possible effects of climate change and anthropic intervention in future scenarios found in this study highlight the need to include these effects in future analyses and conservation programs of V. gryphus.