Spatial Ecology of Jaguars in a Coastal Amazon Island Ecosystem

Abstract

Understanding the spatial ecology of large carnivores is critical for conservation, particularly in insular or fragmented systems where movement is constrained. Jaguars (Panthera onca) are especially informative because their behavior and diet are highly flexible in response to local ecological conditions. We investigated movement patterns, home-range dynamics, and social interactions of jaguars on Maracá-Jipioca Island, a pair of small, seasonally flooded islands within a low-disturbance reserve in the Brazilian Amazon. Using GPS collars, we tracked seven individuals and found that males maintained substantially larger home ranges (mean = 77.8 km²) than females (mean = 19.5 km²). Despite the island's limited area, home-range overlap was low and direct encounters were rare, reflecting territorial behavior similar to mainland populations and contrasting with patterns reported for aquatic-prey specialists. Jaguars moved an average of 7.3 km day⁻¹, with no differences across sex, age, or body size. However, movement speed and activity varied strongly among habitats; individuals moved faster in grasslands, wetlands, and water, and more slowly in forests and mangroves, where resting behavior was more frequent. Unlike the predominantly nocturnal activity reported for continental populations, jaguar activity on Maracá-Jipioca peaked during daylight hours, particularly among females. Jaguars preferentially used coastal areas and their distance to the coast was influenced by tidal variation. Together, these findings reveal a combination of conserved and novel behaviors shaped by the island's ecological context, highlighting the behavioral flexibility that enables jaguars to persist in insular Amazonian landscapes.