Natural history of the American crocodile in a tropical pacific island in Panama, Central America
Balaguera-Reina, Sergio A.
MetadataShow full item record
Conservation of large predators has long been a challenge for biologists due to the limited amount of information we have about their ecology and generally low numbers in the wild. The last decade has made it clear that to implement sound conservation practices, we must increase our understanding of large predators’ ecology, covering all possible aspects. I investigated the natural history of the American crocodile (Crocodylus acutus) on Coiba Island, Panama, addressing a comprehensive ecological framework including four specific topics: crocodile reproductive, population, spatial, and trophic ecology. As part of this work, I also developed two novel approaches focused to identify American crocodiles at the individual level based on the dorsal scute pattern (individual identification pattern recognition IIPR) and to estimate population sizes (using spotlight data) based on the sampling distribution (via bootstrapping) with adjusted confidence intervals. American crocodile reproductive ecology works as a primary driver of the spatial patterns found on Coiba Island, which are also highly influenced by environmental conditions such as precipitation. Hierarchization based on age group and sex through space and time was identified in the study area. Dietary niche overlap analysis showed clear ontogenetic dietary partitioning among juveniles, subadults, and adults. However, the general pattern postulated for crocodylians (small individuals eating invertebrates and adults feeding on larger prey) was not supported by the data collected from Coiba Island, indicating that even adult American crocodiles dwelling in coastal areas rely on more on easy-to-catch/abundant prey such as crustaceans. These results have important implications for the way we see the species as a functional entity of the community, including its interactions and more complex roles in the system than thought before. Overall, American crocodile life history varies considerably from insular to mainland populations and from coastal to in-land populations, demonstrating how “flexible” C. acutus is in terms of habitat requirements. Data suggest that realized niches in the insular populations “shrink” compared to mainland populations due to a reduced availability of resources and an inherent increase of intra and interspecific competition. Results from the present study allow future management and conservation planning to be based on the comprehensive integration of information on the ecology of a Neotropical crocodylians.