Predicting habitat suitability of Caiman yacare and assessing the role of protected areas under current and future climate and deforestation models

Abstract

Climate change and habitat degradation are recognized as serious threats for wildlife and an important aspects to be considered in conservation biology. However, little is known about how such environmental changes might impact crocodylians inhabiting the Neotropics and the effectiveness of Protected Areas (PAs) for long-term species conservation. To fill this gap, we used the Yacare Caiman (Caiman yacare) as a model to explore how climate change and habitat degradation might affect its distribution by 2050 and the effectiveness of current PAs for species conservation in response to future environmental changes. To this end, we estimated C. yacare suitable habitat using an ensemble modeling and consensus approach and assessed the species distribution variation inside and outside PAs as a consequence of two greenhouse emission scenarios (Representative Concentration Pathways [RCPs] 4.5 and 8.5), and three General Circulation Models (GCMs; ACCESS1-0, CANESM2, and MRI-CGCM3) for 2050. We estimated the current suitable habitat for C. yacare to be 854,494 km2 divided across five countries: Brazil (396,476 km2), Bolivia (377,853 km2), Paraguay (38,288 km2), Argentina (35,423 km2), and Peru (6,451 km2). Of these countries, Peru is the only one that can be considered “potential” because the species has not been registered there yet. We found that currently only 26.8% (228,835 km2) of C. yacare suitable habitat is under any type of protection of the IUCN Protected Area Categories System, which is currently well preserved from habitat degradation with only 1.9% reduced due to deforestation. We predicted that on average 56.2% of the current species range might be lost because of climate change and habitat degradation and only 14.7% of its suitable range could be preserved based on the current PAs system. Based on our assessment, we showed that future climate change scenarios and habitat degradation processes will require the establishment of additional PAs as well as the implementation of sustainable management strategies emphasizing corridors and suitable habitat linkages. These integrative approaches can be implemented in several ecoregions including the Pantanal flooded savannas, Cerrado woodlands and savannas, Beni savanna, Chiquitano dry forests, and Amazon moist forests, which we predict will be relatively well-preserved under most of the future climate change scenarios and constituting as priority regions for the long-term conservation of the species and tropical biodiversity.