Responses of American Crocodiles (Crocodylus acutus) to Introduced Species in a Changing Environment: Conservation Implications

Determining the degree of niche overlap or partitioning among sympatric species can inform management practices for species of conservation concern and invasive species, particularly during unprecedented global change. Populations of herpetofauna have substantially declined over the last few decades, and semi-aquatic species are especially vulnerable to habitat alterations and invasive species. Because crocodilians have persisted through periods of intense climatic change, they provide a unique opportunity to study the potential effects of current global change and niche overlap with invasive species. Florida is the only place in the world where alligators and crocodiles coexist, and seven species of non-native crocodilians have also been introduced to the state. Spectacled Caimans currently are the only species known to have established breeding populations within the state, but the degree to which their niche overlaps with native crocodilians is unknown. My dissertation will examine the community ecology of native and exotic crocodilians in southern Florida, with a particular focus on threatened American Crocodiles. Chapter 2 will assess habitat suitability of the southeastern USA for additional crocodilian species and determine whether niche plasticity allowed Spectacled Caimans to establish. Chapter 3 will determine how the ranges of American Crocodiles, Spectacled Caimans, and American Alligators might shift because of changing climatic conditions and assess the potential for human-crocodilian conflict. Chapter 4 will use a multi-stable isotope approach to determine if there is an overlap in foraging habitats between crocodilians in southern Florida. Finally, Chapter 5 will use multi-species occupancy models to determine whether the established crocodilians partition available aquatic habitats in southern Florida. These findings will improve our understanding of coexistence between sympatric crocodilians and inform management practices of both native and introduced crocodilians.

Presenter: Jessica R. Yates 

Advisor: Dr. Joshua R. King