Forest fragmentation and impacts of intensive agriculture: responses from functional groups of the tree community

Abstract

Agricultural landscapes are seen as areas of extreme importance for studying and developing strategies that integrate biodiversity conservation and ecosystem services with food production. The main strategies for intensifying agriculture are based on conventional practices of frequently using agricultural inputs for fertilization and correction of soil pH. Some studies show that these practices generate impacts on nearby forest fragments through soil contamination, causing an increase in nutrient content. The objective of this study was to identify the impacts on the functional groups of sciophilous and heliophilous species of a tree community of 14 forest fragments near agricultural areas under conventional practices, and raised the hypothesis that the higher the fertility of forest fragments adjacent to intensive agriculture modifies the floristic composition of the tree community. The floristic composition of fragments close to agricultural areas are more similar to each other and the General Linear Model (GLM) results show a clear influence of the intensive farming environment on the richness and abundance of the two functional groups in the forest fragments, directly benefiting the abundance of heliophilous species which are also benefited by the greater declivity and smaller fragment area, while the abundance of sciophytes is negatively correlated with these last two variables. The increase of calcium content is beneficial for the richness of heliophilous species, while the increase in phosphorus content influences a reduction in the richness of sciophyte species, which also respond strongly to the isolation between fragments. The results indicate a dominance trend of pioneer species in nutritionally enriched soils, evidencing that the intense adoption of inputs in cultivated areas causes concrete impacts on the diversity of the tree community of forest fragments, being more determinant for the species richness than the size of the fragments.