O emprego medicinal de espécies lenhosas protege-as da pressão para usos madeireiros?

Abstract

Several ethnobiological studies have been showing the impacts of the extraction of timber forest products and indicate some factors that may contribute to the selection of plant species by local populations, such as the availability, and physical-chemical attributes of the species. However, little is known about the interactive effect between local uses, that is, how the use of a species for a given purpose can affect its use for another purpose. In this sense, we propose the hypothesis that species of high importance in a category of more specialized use may have their use reduced to other categories with a more general nature. For this study, we will investigate the interaction between medicinal and timber use, seeking to test the following prediction: woody plants of high medicinal importance are less used for timber purposes than other woody plants, as the first use protects them from the latter. To this end, the investigation was carried out in three rural communities, located within the National Park of Catimbau, in the state of Pernambuco. The free-list technique was applied to identify the woody plants used as medicinal in the community. The interviewees checked grades for the species according to their perceived efficiency for timber purposes and their perceived local availability. For data analysis, a GLM (Poisson family) was performed, whose response variable was the species' timber popularity and the explanatory variables were medicinal popularity, perceived availability and perceived efficiency. Correlations were also performed between the variables explained to observe possible biases in the hypothesis test. Our results point to a small, but significant, protective effect of medicinal use over wood use, which is evidence favorable to the hypothesis. The variables availability and perceived efficiency proved to be important predictors of timber use. The correlations between the explanatory variables ruled out the possibility of bias in the hypothesis test. In this way, the maintenance of the medicinal importance of certain species can constitute an important biocultural conservation strategy.