Modelling impact of climate change and priority areas for conservation of Amazonia's largest primates

Abstract

Climate change and habitat loss are recognized as two of the main current threats to biodiversity, negatively affecting ecosystems around the world. Being able to anticipate how biodiversity will respond to these threats and identifying priority areas for conservation planning and implementation of management actions will be crucial to mitigate the climate crisis and other important anthropogenic impacts. Ecological niche models (ENMs) have become a practical and key mechanism to help in the identification of such areas because it can provide detailed predictions of species distributions and environmental requirements, assisting in decision making and management for nature conservation. In this thesis, we used ENMs to estimate current and future potential distributions of nine extant taxa of ateline primates (Platyrrhini, Atelinae) across the whole Amazon basin. We used these estimations to identify and quantify potential range changes and refugia at taxon and complex levels under two climate change scenarios (Chapter I). Additionally, we quantified current and future habitat loss, and identified high priority areas for conservation combining ENMs and geospatial abundance models (Chapters II and III), taking as examples two taxa of atelines (Ateles chamek and Lagothrix lagotricha cana) that have considerable portions of their distributions in areas highly impacted by deforestation. For these purposes, we used throughout the thesis a dataset consisting of 596 occurrence records covering all taxa of Amazonian atelines, 77 geo-referenced abundance records for A. chamek and L. l. cana, and a comprehensive set of predictor variables including vegetation structure, topography, soil properties, bioclimatic layers, and surface reflectance data from Landsat TM/ETM+. We found that all taxa are likely to experience pronounced range losses irrespective of climate change scenarios. Predicted ateline richness exhibited a broadly similar spatial pattern under both climate change scenarios with a visual decrease in areas with higher richness, and a possible redistribution/migration along the northernmost parts of western Amazonia. Refugia from climate change for the conservation of the whole complex were mostly concentrated in the western part of the Amazon basin, especially in the southern region. Furthermore, we found that L. l. cana, taxon with one of the largest distribution ranges among all atelines, can potentially lose up to 58% of its forest habitat in the next 30 years, and only 39% of its range are within protected areas. We also identified high priority areas for conservation of A. chamek e L. l. cana that holds jointly suitable habitat and high predicted densities for both taxa. Notably, these areas were mainly concentrated in the southwestern portion of the Brazilian Amazon, an area considerably threatened by intense deforestation. In conclusion, we identified high priority areas for conservation and hotspots of vulnerability to climate change for all Amazonian atelines. The complex of Amazonian atelines can serve as an indicator group when identifying hotspots of vulnerability to climate change and refugia for conservation, thereby providing essential information for prioritizing Amazonian conservation efforts and helping to target conservation planning amid pervasive environmental change.