The dark side of the black caiman: spatial and temporal trophic niche variations

A floating scientific platform was built in the Kaw marshes (French Guiana) to study this unique and still unknown ecosystem. Preliminary research has shown this pond is seasonally colonized by a large population of black caimans and represents the most important breeding site for many rare bird species. At the top of the food web, the black caiman is the largest neotropical predator and a particularly threatened crocodilian species, which implies that they have a major structuring role within the swamp ecosystem. Our preliminary study during the dry and wet season revealed important seasonal variations in the structure of the Agami pond population and the temporal presence of large caimans during the wet season (rarely observed in the Kaw marshes). Thus, coupling isotopic analysis (controlled diet and field studies) and different monitoring approaches (behavioral, microchip marking and satellite Argos tracking), we aim to conduct a detailed study of the Agami pond black caiman population: (i) to study the structure of the population and its variation over time, (ii) to estimate the intra- and inter-annual movements of individual caimans and identify potential feeding, reproductive and nesting areas in the Kaw marsh and (iii) to estimate this top predator’s role on the marsh’s ecological functioning and survival throughout the year. For this purpose, we will compare different field periods during the wet and dry seasons characterized by different hydrological and ecological patterns. This new information will help predict species response to disturbance, which is a prerequisite to effective conservation plan management involving local people and wildlife administrations. Finally, by coupling Argos tracking and stable isotopes, we will collect significant and valuable data for future applications at a global scale.