Banca de DEFESA: ALEX EUGENIO DE OLIVEIRA

BETA-DIVERSITY IN HERBS METACOMMUNITY AT THE ECOLOGICAL STATION OF CUNIÃ, RONDÔNIA

Amazon, Biodiversity, Ecology, Herbs, Environmental variables

Herbs are an important group, as they have adaptations to the environment in which they live and respond to more subtle environmental changes, in addition to having human and economic utility. Studies on forest understory herbs can provide data to infer about the conservation status of forest communities. This study aims to describe the composition and structure of the herb community, as well as to quantify the components of abundance-based beta diversity and to determine the relative importance of environmental and geographic distance in the variation of the beta diversity of the herb community in Riparian and Terra Firme at ESEC Cuniã. 48 plots measuring 250x2m were implemented, 18 of which were riparian and 30 of Terra Firme, where edaphic and hydrological data, litter depth and abundance of herb species were collected. The Riparian and Terra Firme environments presented similar species composition, however with significant differences in the pattern of relative diversity and abundance of the species. The Riparian and Terra Firme environments presented similar species composition, but with significant differences in the pattern of diversity and relative abundance of species. The Riparian environment added new species and increased the density of others, while the Terra Firme environment was more diverse and with the distribution of species and abundances more homogeneous between the plots. Beta diversity was caused by the replacement of species between sites and not by the loss of existing species in the richest plots. This pattern proved to be congruent in both environments. The total variation of the quantitative beta diversity explained only by the environmental distance was 15% and 24% for the Ripario and Terra Firme environments and by the pure geographic distance it was 1% and 6%, respectively. Thus, the high proportion of variation in floristic distances that was not explained (70-95%) by geographic distance or our environmental dataset could be attributed to other unmeasured factors. The floristic variation for each taxonomic group had different sets of environmental variables, indicating that each group has different requirements. Litter depth, clay percentage, area and organic matter were the variables that were present in most of the regression models. The rotation, range and spatial permanence of the species is influenced by the local environmental heterogeneity, thus maintaining different characteristics that contemplate different environments is important to conserve the diversity of herbs in Amazonian environments.