Understanding foraging ecology is an important element of effective conservation strategies. While it has been suggested that some populations of Antillean manatees inhabiting freshwater systems experience seasonal availability to food, no study has examined it quantitatively. In this study, plant species richness, diversity, and abundance were examined monthly in four contact lakes in the wetlands of Tabasco Mexico from August 2010-July 2011. A total of 415 plots were surveyed, in which 72 plant species were identified representing 63 genera and 45 families. Only one submerged species was found. Water levels fluctuated more than 6 m, and based on the water levels the following seasons were determined: high water (September-October), receding water (November-February), low water (March-June), and rising water (July-August). Plant species richness, diversity, and abundance were greatest during the rising water season and lowest during the low water season. No plants were available in April-June, which represented the majority of the low water season. Species richness, diversity and abundance were significantly affected by month and positively associated with water levels. The availability of the different plant growth forms was also significantly influenced by season. Despite the relatively high plant species richness and abundance found in the habitat, on any given month manatees in Tabasco had access to only 0-39 species and an average of 14. In addition, they had very restricted or no access to plants during the low water season, which suggests they were forced to fast. This may have important implications for rehabilitation and relocation efforts of stranded and orphaned manatees. If reintroduction efforts are to succeed, the variability of plant species and abundances demonstrated by this study should be taken into consideration when feeding captive animals that are going to be released back into the wild.
Available at: http://works.bepress.com/daniel_gonzalez_socoloske/6/