Ecological grouping and edge effects in tropical dry forest: reptile-microenvironment relationships

We evaluated the effect of tropical dry forest edges in fragments on reptile structure and ecological groups, and their relationship to 15 environmental variables in the Caribbean Region, Colombia. We used 15 pasture-edge-interior gradients and 12 permanent linear transects per gradient, sampling them on three occasions between January and December 2006. We recorded 35 species (pasture: 15, forest edge: 28, forest interior: 16). Reptile structure was different along the pasture-edge-interior gradient and the magnitude of the influence of the edge effect on the abundance of the most common species changed from the dry to rainy season. We identified seven ecological groups based on three fixed functional traits: species habit, size and reproductive mode. The proportion of species belonging to each ecological group was different between the pasture and forest habitats, but there were no differences between the forest edge and its interior. Four of the seven ecological groups inhabited pasture and the forest interior, and all of the ecological groups were represented in the forest edge. The ecological group with oviparous small and diurnal species accounted for the 50 % of the species inhabiting the forest interior. Reptile structure and ecological groups were both related to patch size, elevation, herbaceous cover, percentage of bare soil and temperature, but explanatory power differed. We suggest that the conservation and management of tropical dry forest reptiles should take into account species traits so that rather than using information for a single species, a more generalized community approach is used.