New light on the floristic composition and diversity of indigenous territory and national park Isiboro-Sécure, Bolivia

A floristic inventory of woody plants was conducted in the tropical forest vegetation of Indigenous Territory and National Park Isiboro-Sécure, Bolivia. All stems with a diameter at breast height ≥2.5 cm were sampled in two terra firme and two floodplain 0.1 ha forest transects, resulting in a total of 447 species and 1,564 individuals. Results correspond fairly well with other Bolivian and neotropical studies in terms of species distribution patterns, physiognomy, family distribution, growth forms, as well as species and family richness. Our finding that only 6% of all species occurred in all four transects, while 69% was found in only one transect, supports the hypothesis that Amazonian plant communities are dominated by a limited set of species, whereas the large majority of species follows a patchy distribution. However, Fisher’s Alpha index values were much higher than was expected from literature data. It is hypothesized that this might be related to high local precipitation levels and/or natural and (historical) anthropogenic disturbance regimes. Although much more research is necessary, our results suggest that TIPNIS represents a strongly underestimated local center of plant diversity.