Lessons from a palm: genetic diversity and structure in anthropogenic landscapes from Atlantic Forest, Brazil

Abstract

Habitat loss threatens biodiversity in tropical forests, having harmful effects on population dynamics and, ultimately, determining the evolutionary destiny of species. Thus, understanding how habitat loss affects microevolutionary processes is an important step in the conservation of genetic resources. However, few studies have explored landscape genetics for plants in tropical environments. Our study evaluated the effects of a landscape-scale reduction in forest cover on genetic diversity and structure of Euterpe edulis (Arecaceae). The research was conducted in Atlantic Forest landscapes in Northeastern Brazil. We randomly chose 16 forest sites, each located in a 13 km2 landscape with forest cover ranging from 6 to 83 %. After a survey of adults and seedlings in each sampling site, we found a minimum of five individuals of E. edulis at nine sites and sampled leafs from all adults within a 15 × 400 m plot and all seedlings within a 2 × 400 m subplot in each sampling site. We found that the gradient of remaining forest cover at the landscape scale did not affect the genetic diversity measured by any of the descriptors analyzed and each sampling site still harbored populations with high levels of genetic variability. However, we detected the presence of two distinct genetic groups with signs of admixture; the structural pattern of these groups differed between adults and seedlings, mainly in less forested landscapes areas. We believe that E. edulis is a good example of a tropical palm that is experiencing local extirpation before suffering loss of genetic alterations.