Drifting survival: impacts of climate change on the distribution of continental chelonians in the Amazon

Abstract

Assessing the effects of climate change (CC) on species distribution is necessary for understanding its consequences on biodiversity. We employed species distribution models (SDMs) to assess how CC affects where these species can survive using CC scenarios for the Amazon and current chelonian distribution data. Current projections suggest significant changes in Amazonian river hydrology due to climate change, impacting flow patterns, precipitation, flood extent, and intensity across seasons. In this context, chelonians will be significantly impacted by the changing hydrological patterns in Amazonian waterways. These changes are critical for the nesting and feeding habits of the chelonians, as they rely on river levels and flood periods for these activities. Considering these scenarios, our results show that the vast majority of analyzed species have lost extensive areas environmentally suitable for their occurrence, with the most impacted being Mesoclemmys nasuta, with a loss of distribution range of up to 98.93%, Phrynops tuberosus with a loss in distribution range of up to 97.87%, Podocnemis erythrocephala, with a loss in distribution range of up to 66.26%; Mesoclemmys raniceps, with a loss in distribution range of up to 63.46%, and Chelonoidis denticulatus, with a loss in distribution range of up to 61.62% in the more pessimistic scenario. Our results highlight the need for medium- and long-term mitigative governmental actions on different scales, which will be essential to reduce the impacts of inevitable climate changes on chelonians, thereby avoiding the possible extinction of these species in the Amazon region.