Community of medium and large-sized mammals and functional diversity in a tropical rainforest of Southern México under different degrees of human pressure

Abstract

Functional diversity quantifies the distribution and range of functional traits of species that influence ecosystem processes.  We evaluated the functional diversity of the medium and large-sized mammals in a tropical rainforest in Southern Mexico to determine which landscape characteristics associated with human activities affected the composition of mammal functional diversity and functional group abundances.  We used camera-traps to document the diversity and composition of medium and large-sized mammals at four sites with different levels of protection and management.  We estimated species richness, diversity, and functional diversity for each site, and compared these indices between sites to understand the effects of biodiversity loss in ecosystem dynamics and to detect ecological patterns driven by human perturbation.  The density of human settlements was the main covariate related to low species richness and low abundance of large mammals with specialized diets and low population densities.  Poaching and other human activities in forested areas near human settlements might have caused large herbivore and specialized carnivore populations to decrease, and populations of medium-sized rodent species to increase.  Our results indicated that human perturbation in forested areas had also an impact at the functional level reducing the abundance of some functional groups, and this might have negative consequences for tropical rainforest functions in the long term.  Effective management actions should be implemented in Protected Areas with a high density of human settlements nearby to prevent the decline of mammals’ functional groups and negative consequences for tropical rain forests’ ecological functions.