Phylogenetic interactions among lianas in a southeastern Brazilian semideciduous tropical forest

Abstract

Biotic interactions play an important role in structuring community spatial pattern, which is also influenced by species resource use and reproductive success. Since plants are sessile organisms, biotic interactions may be reflected in the pattern of species co-occurrence. The pattern of species co-occurrence may change with the predominance of positive or negative interactions among the species along evolutionary history and environmental gradients. Considering the relative influence of phylogeny and environmental gradients, we expected lianas co-occurring on the same host tree (phorophyte) to (1) be phylogenetically more related than expected by chance; and (2) respond to abiotic variation along a gradient. We sampled 1ha with 100 plots of 10×10m each in a tropical semideciduous forest in SE Brazil. We investigated the presence of phylogenetic signal in climbing traits of lianas co-occurring on the same phorophyte and tested for the co-occurrence of liana-phorophyte pairs across the space and environmental gradients. Closely related liana species co-occurred more frequently than expected by chance on the same phorophyte species. Climbing traits of liana species showed a significant phylogenetic signal. Canopy openness had a high influence on the co-occurrence of lianas. We assume that stochastic processes, such as dispersal limitation, fragment history in relation with canopy openness, are the main drivers of the number of lianas co-occurrence on microscale.