Understanding phylogenetic (PD) and functional diversity (FD) following worldwide biodiversity loss is an urgent task. Non-volant small mammals are highly diverse representing more than 60% of all mammal species and play an important role on ecosystem functioning and on shaping communities and landscapes. The Brazilian Atlantic Forest (AF) hosts 97 small rodent and 22 marsupial species even though it has less than 12% of its original cover remaining. Here we compiled a dataset of 283 communities and test how fragmentation and defeunation affects PD and FD of small mammals.We used the species cytochrome b to construct the phylogenetic tree of the AF small mammals which we calculate the PD value of each community. Also we calculate the FD of each trait and tested its significance with a null model approach followed by a standardized effect size (SES) for each metric. Then PD and FD were the response variables on the Linear Mixed-Effects Models.
Results/Conclusions
We found 91 sites (32.1%) showing higher overall PD than expected by null model. Significant higher PD was also detected for body mass and tail length (211 sites, 74.5%), activity (85 sites, 30%), habitat (64 sites, 22.6%) and food type (48, 16.9%). Defaunation was the main mechanism explaining changes on small mammals PD whilst activity was the main trait affected by defaunation. The dominance of divergent traits on communities with high FD is assumed to promote the presence of species with complementary trait values, leading to the absence of functional redundancy. Our results showed that the species have more functional redundancy than complementarity in most of the communities. Given that large mammals control mainly generalist and abundant small mammals and that species loss is not a random process, one can expect that phylogenetically and functionally unique species may be lost more quickly than those phylogenetically closer and functionally redundant in defaunated areas. Evaluate the loss of functional and phylogenetic diversity may help to understand how to conserve communities composed by species with different evolutionary histories that play distinct functions in the ecosystem.