Human impacts, habitat quantity and quality affect the dimensions of diversity and carbon stocks in subtropical forests: A landscape-based approach

Fragmentation is recognized as one of the main factors affecting species and functionality losses in tropical landscapes. In this study, we assess how landscape quality and quantity affect taxonomic and functional diversities and carbon stocks in the Atlantic Forest. We used a large dataset, which comprises 92,754 adult trees of 668 species, distributed over an area of 95,733 km2 in the state of Santa Catarina, southern Brazil. In each plot, we quantified the taxonomic diversity (species richness), the functional diversity (functional richness), and the aboveground carbon stock and related it to different landscape metrics (fragment area and total area, number of fragments, total edge area, index of the largest fragment, effective network size and aggregation index) and anthropogenic impacts in three surrounding landscape buffers (radius 1000, 3000 and 5000 m). We built multiple regression models, selecting the best models (Akaike's criterion), to assess the influence of the landscape and anthropogenic index on diversities and carbon stocks. Our study shows that the landscape quantity and quality, and the anthropogenic effects are factors that negatively affect the carbon stock, reinforcing that smallscale exploration, within the fragment itself, is an important factor in reducing diversity and carbon stock. The importance of considering local exploitation has important implications for conservation, and these results bring important insights for conservation, especially for forest fragments in anthropized landscapes, where exploration within the fragments are factors that interfere in the conservation and maintenance of biodiversity and ecosystem functioning.