Impacto das mudanças climáticas nos cervídeos do Brasil

Abstract

Climate change is known to be one of the primary causes of biodiversity loss in the world today. Deer are one of the largest mammals inhabiting South America and have experienced massive effects of climate changes over the last few decades. Here, we aim to understand how climate change has affected four deer species that occur in Brazil and quantify how much of their distribution is protected in reserve designs. First, we built species distribution models (SDM) with an ensemble forecasting approach using six methods (bioclim, domain, mars, gam, svm and brt) for the species Mazama americana, Mazama gouazoubira, Ozotoceros bezoarticus and Blastocerus dichotomus under current conditions. For each species, we used a unique set of bioclimatic predictors that best define their individual climatic niche and considered South America as the geographic extent. Next, we forecast the future distributions of the four deer species to the end-of-century (2100) for two scenarios (SSP 245 and SSP 585) that include great challenges to mitigation and adaptation in the face of global warming. Finally, we evaluated if deer species are protected in reserve design, by considering two broad management categories: sustainable use and strictly protected areas. Climate change will affect all deer species, which are expected to reduce their geographic distribution. Our results indicate that B. dichotomus will reduce its distribution by roughly 53.3% in an optimistic scenario (SSP 245), while in a pessimistic scenario (SSP 585) its distribution will reduce up to 80%. M. americana is also expected to lose more than 80% of its suitable distribution area in the pessimistic scenario. In addition, M. gouazoubira and O. bezoarticus expect to see reductions in their suitable distribution areas between 30% to 60%, in optimistic or pessimistic scenarios respectively. There is low representation of deer species in protected areas (PAs) and strictly protected areas have safeguarded less than 5% of their distribution. Today M. americana is the most protected species at 4.54%, while B. dichotomus has less than 2.25% of its suitable area remaining in strict nature reserves. Protected areas of sustainable use protect 10.63% of suitable distribution areas for M. americana´s geographic distribution in the current conditions, but less than 4% of B. dichotomus´s suitable areas reside in PAs. In future scenarios, B. dichotomus should lose suitable areas in strictly protected PAs with only 1.78% of suitable areas remaining, while sustainable use will remain at 4.39%in the worst case scenario. We have shown how climate change will affect deer species and demonstrated that species remain unprotected under both current and future scenarios. Although there is a National Action Plan for Brazilian deer species, we highlight the importance of including climate change effects into conservation efforts to safeguard biodiversity.