Patterns of Biological and Utilitarian Diversity of Plants Through a Dry Forest Precipitation Gradient

The environment plays an important role in resource selection by human groups. For example, the same environment shared by different cultures tends to have a greater similarity of useful plants. The present study departs from an innovative perspective, analyzing the factors that influence species richness and their versatility and utilitarian redundancy in a precipitation gradient in an area of Caatinga in the semi-arid region of Pernambuco, Brazil. There was no difference in richness along the precipitation gradient, and the utilitarian redundancy model (URM) indicated no relationship between the proportion of species used and total richness. The versatility hypothesis test showed that environments with lower species richness are more versatile and have a greater number of uses for the same species. The URM led us to the interpretation that the availability of species in the environment cannot be considered a decisive factor in the selection of useful plant resources. One differential of this study was the possibility of testing our hypotheses and verifying the effect of a gradient over a relatively short geographic range.