Leaf venation in tree species along a human-disturbance gradient of Atlantic Forest, SP.

Abstract

Works concerning tropical forests have improved knowledge about their role in worldwide biodiversity conservancy and source of environmental services essential to human life. In this context, Atlantic Forest (AF) has a remarkable importance in Brazil. The forest is considered one of the 5 major global hotspots. Located near the largest national urban centers, it provides environmental services as water supply for human consumption and for hydroelectric power and row material. The AF have suffered more intense anthropic disturbance since the first arrival of Europeans, consequently it is highly fragmented and only a minor portion of its original cover remains. Tree species are of remarkable importance for the maintenance of environmental services, significantly participating in the water cycle and forest primary productivity. The vein organization pattern (venation) is closed related to carbon and water metabolism in plants. Venation affects water conductibility, stomatal conductance and photosynthetic efficiency of plants and has being used to predict physiological proprieties of leaf. Recent studies investigate if veins have a central role in leaf economic spectrum (LES; a coordination and tradeoff of functional traits in respect to resource use in an integrated economic view), whereas leaf mass/area ratio (LMA) is possibly the most important trait, capable to indicate if a species or functional group has high productivity and low lifespan or low productivity and high lifespan. Moreover, venation may be useful to proxy the environment effects on plants water and carbon economy and might offer a predictive approach based in leaf architecture. Therefore, in order to understand the effects of human disturbance in functional groups and species of AF, carbon and water metabolism and provide insights about the role of venation regarding LES this work aim to investigate vein traits related to vein density (VD) along a disturbance gradient and their relations with LMA and its relation to leaf maximum photosynthetic rate (Asat), photosynthetic rate in high CO2 level (Amax), transpiration rate (E) stomatal conductance (gs) and water use efficiency (WUE). The study area comprises forest permanent plots (K, M, N e T) and forest fragments of the Thematic Project Biota/FAPESP/NERC "ECOFOR: Biodiversidade e funcionamento de ecossistemas em áreas alteradas pelo homem nas Florestas Amazônica e Atlântica" (Projeto Temático FAPESP no.12/51872-5).