Patrones de diversidad de plantas en un gradiente de baja elevación en el Chocó, Colombia, usando especies indicadoras (Rubiaceae)

Rubiaceae is a plant family widely distributed and diversified in tropical environments. This group of plants has been used to determine patterns of diversity in the Neotropical region. Here, the changes in the diversity and the species composition of the Rubiaceae family across an altutudinal gradient (45-100, > 100-200, > 200-300 m) in the serranía de Baudó, Chocó, Colombia were evaluated. We established 30 plots of 400 m2, 10 in each of the elevational zones (0.4 ha). In each plot, the number individuals per specie of Rubiaceae was recorded. In total, 54 morphospecies and 21 genera were recorded. Psychotria (33.3%), Faramea (28.6%), Coussarea (23.8%) and Palicourea (19%) were the most species-rich genera. The altitudinal zone with more species was 45-100 m (57.4%), followed by > 100-200 m (51.8%) and > 200-300 m (26%). The lower altitudinal zones (45-100 and > 100-200 m) showed greater diversity than the highest elevation zone (> 200-300 m). The floristic similarity among communities was less than 60%. In overall, plant diversity decreases with elevation and changes in species composition occur across gradients of high or low elevation.