Modelling 21st century refugia and impact of climate change on Amazonia's largest primates

Edaphic and vegetation conditions can render climatically suitable sites inadequate for a species to persist, constraining the amount of suitable habitat and the possibilities of tracking preferred climatic conditions as they shift in response to climate change. We combined climatic and remotely sensed data to model current and future distributions of nine extant taxa of ateline primates across the Amazon basin. We used the models to identify and quantify potential range changes and refugia of suitable habitat from the present to the latter half of the 21st century. We applied an ensemble forecasting approach for species distribution models using 596 spatially rarefied occurrences. We parameterised these models combining reflectance data from a basin-wide Landsat TM/ETM+ image composite, and three sets of bioclimatic layers containing data for the current time period, and two different (moderate and worst-case) climate change scenarios for 2041-2070. Eight out of nine taxa are likely to experience pronounced range losses, with seven of them predicted to lose over 50% of their currently suitable habitats irrespective of climate change scenarios. Modelled ateline richness exhibited a broad decrease in high-richness areas, and a possible redistribution along the northernmost parts of western Amazonia. Refugia from 21st century climate change for the whole complex were mostly concentrated in western Amazonia, especially in its southern part. We identified hotspots of vulnerability to climate change and 21st century refugia for all Amazonian atelines while accounting for habitat characteristics that are important to guarantee the continued existence of suitable habitats for these strictly arboreal taxa. Increasing the understanding of climate change impacts on Amazonia's largest primates can help to inform spatial conservation planning decisions and management to sustain forest-dwelling biodiversity over large areas such as Amazonia.