Drivers of Habitat Selection by the Endangered Great Caribbean Manatee in Coastal-marine Ecosystems
Habitat loss, movement ecology, resource selection functions, sirenia, endangered species
Habitat selection is a fundamental aspect of animal movement and behavior, involving strategies that have implications for population regulation, species interactions, community structure, and the generation and maintenance of biodiversity. The Greater Caribbean Manatee is a megaherbivorous aquatic mammal with high environmental plasticity, found in a variety of coastal marine ecosystems from the USA to Brazil. The subspecies is locally threatened due to intense poaching over the past few centuries, which has led to the disruption of small populations. Calf stranding, possibly related to habitat loss, is now considered the main threat to manatee conservation in Brazil. In this study, we aimed to understand habitat selection patterns and their variation across study sites, sex, age classes, and between captive and wild manatees in northeastern Brazil to inform conservation policy. We used fine-scale GPS telemetry data from 20 tagged manatees and applied autocorrelation-informed Resource Selection Functions (RSF) using (i) seagrass meadows, (ii) coral reefs, (iii) estuaries and (iv) freshwater springs as environmental predictors. As a proxy for anthropogenic impact, we also used a predictor combining multiple human activities at sea, which imposes substantial pressures with a subsequent degradation of manatee habitat. All environmental predictors had statistically significant results at the population mean. Estuaries (1.52), springs (0.85), and seagrass (0.77) were found to have positive estimates, indicating that the manatees select these habitats. The human impact was also positive (1.12), suggesting that the habitats selected by the manatees overlap with human impacted areas. Coral reefs (-0.92) were found to have a negative estimate, indicating that the animals avoid this habitat. Our results confirm the vital role of seagrass and freshwater in manatee movement behavior. The selected habitats overlap with human impacted areas, particularly in areas close to urban centers and ports, creating barriers to their free movement and reconnection of subpopulations, and highlighting the importance of conserving and restoring these marine coastal habitats.