Human Landscape Modification in Placencia, Stann Creek District, Belize: Possible Implications for Crocodile Hybridization

Abstract / Resumen / Resumo

Habitat destruction and degradation represent the most significant contemporary threats to populations of American (Crocodylus acutus) and Morelet’s (Crocodylus moreletii) crocodiles throughout their respective ranges. In addition to destroying nesting sites, escalating inter- and intra-specific competition, and increasing instances of human-crocodile conflict, it has been suggested that habitat decline may also be contributing to recent hybridization that could threaten each species’ genetic integrity. In this paper, we use the Placencia Peninsula in southern Belize as a case study, synthesizing remote-sensing based quantification of historical land use / land cover (LULC) change in the study area with insights from literature to demonstrate the potential role of LULC change as a driver of crocodile hybridization in the area. Using visual interpretation and supervised classification of satellite imagery, we found that between 1976 and 2017 built-up land, agriculture, and aquaculture expanded dramatically in the study area at the expense of mangrove and littoral forests, evergreen broadleaf forests, and savanna. The widespread conversion of traditional crocodile habitat to anthropogenic land uses likely increased the concentration of suitable American and Morelet’s crocodile habitat within a diminished sympatric zone, making Placencia’s increasingly human-modified landscape more conducive to crocodile hybridization in 2017 than it was four decades prior. With similar landscape conversions taking place throughout the crocodiles’ overlapping zones in North and Central America, hybridization may soon represent an increasingly substantial threat to both species’ conservation statuses.