Plant parentage influences the type of timber use by traditional peoples of the Brazilian Caatinga.

Local populations select different plants to meet their demands, so that morphologically similar species can be more used for a given use. Herein, we seek to understand whether plant species that are phylogenetically closer together are used more similarly than distant species in the phylogeny. Ethnobotanical data were collected in five rural communities in a semi-arid region of Brazil. A total of 120 local experts were selected and interviewed using semi-structured questionnaires. The people's knowledge of plants was organized into usage subcategories. We estimated the redundancy values for the mentioned species, and we compiled data from the literature on the wood density values of the cited species. We constructed our phylogenetic hypothesis of useful plants and used comparative phylogenetic methods to estimate the signal. Our results showed a strong phylogenetic grouping for both tool handle and craft uses. We observed a moderate phylogenetic grouping in which related cited plants exhibit similar redundancy and a weak grouping in which cited plants present similar wood density values. Our results revealed the importance of using phylogeny for useful plants. We conclude the phylogenetic proximity of useful plants and the lower redundancy for some species in our study may suggest greater use pressure, given that few species fulfill the same function.

Vegetation cover and seasonality as indicators for selection of forage resources by local agro-pastoralists in the Brazilian semiarid region.

Local knowledge and uses of forage resources are highly dynamic, and can be mediated by multiple factors, such as seasonality, floristic diversity and the morphophysiological characteristics of plants. We investigate how seasonality and vegetation cover mediate the use of forage resources. The study was carried out with agro-pastoralists from two areas of Brazilian semiarid region. To select the areas, we used the normalized difference vegetation index. We selected one area with low vegetation cover (Area I) and another with high vegetation cover (Area II). Respondents were selected using the snowball technique. Using semi-structured interviews, we collect the information about forage use in the dry and rainy seasons, preferences of ruminants and specific characteristics of plant species. A total of 57 informants were interviewed in the two areas. We used the Chi-square test to assess differences in the richness of species cited between areas, seasons (dry/rainy), origins (exotic/native) and strate (herbaceous/woody). Our results revealed that agro-pastoralists living in the area with the highest vegetation cover (Area II) cited a greater number of species. We found that the use and selection of species is guided by a series of functional characters, related to palatability and nutritional value, which change between seasons. These results highlight the vast knowledge of ecological characteristics of species and diet of ruminants acquired by agro-pastoralists during field experience, with seasonality defining the use of species. Different from what we expected, the richness of exotic species mentioned did not differ between areas. This diversity of information contributes to a better understanding of the use of forage resources and indicates the importance of including local experiences as strategies to ensure proper use and provide insights for the conservation of local resources.