Abstract

JIMENEZ-DOMINGUEZ, Darwin  and  OLIVERA-GOMEZ, León David. Habitat characteristics of antillean Manatee (Trichechus manatus manatus) in fluvial lake systems of southern Gulf of México. Therya [online]. 2014, vol.5, n.2, pp.601-614. ISSN 2007-3364.  https://doi.org/10.12933/therya-14-205.

Introduction: Studying a species habitat is a tool for researchers and stake holders to find key ecological characteristics to be used in management actions. Freshwater systems comprises most of the habitat of Antillean manatees, however the habitat features of these systems are still poorly understood. The objective of this study was to explore habitat variables related most to the use of freshwater systems by the Antillean manatees on the low basin of Usumacinta river. Methods: We built generalized linear models using data on presence/absence and from sightings, achieved by direct and indirect sources on 62 navigations, between March 2006 and November 2007. For the models we used four types of variables: biological, physical, anthropic and from landscape, all previously reported as important in the habitat use of Antillean manatee. Results: In general, the area (Fig. 1) had warm and shallow waters (2 to 4 m) with low transparency; waters are mostly lentic except for secondary and main rivers; vegetation was mostly of bank grasses and shrubs and boat traffic was medium. From the 19 initial habitat variables evaluated here, the best presence-absence model included transparency, distance to confluence and submerged vegetation (tables 1 and 2). The best sightings model was built with current and distance to streams (tables 1 and 2). Discussion and conclusions: On the study area, manatees use deeper lentic environments near to feeding areas, like streams or confluences, where they find shelter. Conectivity is important in the habitat of manatees, they could be using shallow lakes to feeding in times of the day not comprised in this study, but then traveled to deeper watercourses using confluences. Manatees have also been reported to use these environments in Central and South America. Along freshwater systems associated to Usumacinta River, manatee is still abundant, confirming this region as a key area for manatee conservation in México. Results of this study had been use to classify the region and to prioritize research and conservation actions in a landscape scale.

Keywords : freshwater systems; Generalized Linear Models; habitat; México; Sirenians; Usumacinta River.