DISTRIBUTION AND HABITAT PREFERENCE OF THE SWAMP CROCODILE (Crocodylus moreletii) IN THE SIAN KA'AN BIOSPHERE RESERVE

Abstract

Crocodiles are considered a key species since they help the proper functioning of the ecosystem with their activities, keeping water courses open and increasing the recycling of nutrients, and providing shelters in the body of water for other species during the dry season. The objective of this study was to assess the characteristics of the habitat that intervene in the distribution of crocodiles in the northern zone of the Sian Ka’an Biosphere Reserve (RBSK). In the months of July to September 2018, we carried out 18 surveys with a team of three people, with a total sampling effort of 120 hours and 349 km covered, which were navigated with a boat on the edge of the lagoons. In both lagoons (Muyil and Chunyaxché) a total of 63 records of Crocodylus moreletii were obtained. Nine habitats were recorded in both lagoons: Mangrove, Sawgrass, Aquatic Vegetation, Everglades palm, Cane grass, Southern bulrush, Mangrove/Everglades palm, Mangrove/Southern bulrush, and Mangrove/Florida thatch palm. Principal Component Analysis showed that Rhizophora mangle and Cladium jamaicense are important in habitat preference in relation to crocodile size categories. The hatchlings, subadults and adults present a higher frequency of distribution and preference in the Mangrove habitat. On the other hand, the juveniles recorded a predominant distribution in the Sawgrass habitat. Emphasis should be placed on the relevance of the red Mangrove and Sawgrass species as essential habitat characteristics that determine the distribution and preference of the Morelet’s crocodile in the northern zone of the RBSK.