Modelando a distribuição geográfica do caranguejo-uçá, Ucides cordatus (Linnaeus, 1763), para informar prioridades espaciais de conservação no presente e no futuro

Abstract

The mangrove crab, Ucides cordatus, is a typical crustacean of mangrove ecosystems, playing a fundamental ecological role in nutrient cycling and soil oxygenation. In addition to its ecological importance, this species represents a crucial fishing resource for Brazil's riverside communities, especially in the North and Northeast regions. However, concerns are emerging about the significant changes in its distribution resulting from the current global warming scenario. Thus, understanding the possible trends of geographic change in the species is essential to guide conservation strategies aimed at preserving the mangrove crab and the sustainability of mangrove ecosystems in the future. The objectives of this study were to generate ecological niche models to predict the current geographical distribution of U. cordatus, to create projections of future distribution by testing the “poleward shift” hypothesis and to select priority areas for the conservation of the species in two future climate change scenarios. To this end, data on the species' occurrence was collected from the literature and specialized databases. The environmental variables were obtained from WorldClim and selected based on the species' main physiological needs, excluding those with a high degree of correlation. Thus, the minimum temperature of the coldest month (mm), precipitation of the wettest month (mm) and precipitation of the driest month (°C) were selected. Future forecasts considered climate scenarios between 2041 and 2060, using SSPs 126 (optimistic) and 585 (pessimistic). The modeling used the MaxEnt algorithm and the models showed high predictive performance (AUCtrain = 0.91, AUCdiff = 0.12, delta AICc = 0). In addition to confirming the known distribution of the species and indicating a possible increase in the distribution limit towards the south. Spatial prioritization highlighted areas on the coasts of Amapá, Pará, Maranhão, São Paulo and Paraná as priorities for conservation. The results suggest that climate change could significantly alter the distribution of U. cordatus, highlighting the need for adaptive conservation strategies to ensure the persistence of the species.