Carbon stock in aboveground biomass and necromass in the Atlantic Forest: an analysis of data published between 2000 and 2021.

Synthesising knowledge on carbon stocks is an essential tool for understanding the potential of forests to store carbon and its drivers. However, such a synthesis needs to be constructed for the Atlantic Forest due to various methodological approaches and biogeographic heterogeneity. Thus, here we conducted a bibliographic search (2000 to 2021) on carbon stocks in the biomass and necromass of Atlantic Forest ecosystems to understand the variation in stocks and their explanatory variables. Drivers included spatial (altitude, forest size) and climatic (precipitation and temperature) variables, and successional stages. Based on the information in 46 articles, biomass exhibited the highest carbon stock (96%), in Mature Forests (MF), with an average of 125.34±40.3 MgC.ha-1, whereas Secondary Forests (SF) stored 82.7±38.2 MgC.ha-1. The carbon in the necromass varied from 1.63 to 11.47 MgC.ha-1, with SF exhibiting 3.90±2.73 MgC.ha-1 and MF 4.31±2.82 MgC.ha-1. Only average annual precipitation and successional stage positively explained the carbon in Atlantic Forest. This research clarifies the function and potential of Atlantic Forest fragments for storing carbon and reinforces need for conserving mature forest patches throughout the biome since one hectare of mature forest can store almost twice as much carbon as one hectare of secondary young patches.

Integrating trait and evolutionary differences untangles how biodiversity affects ecosystem functioning.

Biodiversity and ecosystem functioning (BEF) research advocates that biodiversity loss has a drastic alteration on ecosystem functioning. However, studies have barely investigated how the evolutionary dependence of species traits affects EF. Here, we developed an integrated approach combining functional (FD) and phylogenetic diversity (PD) into a single space to disentangle the effects of diversity on leaf decomposition. We conducted an experiment manipulating plant leaves into litterbags containing four species (from a pool of 27) combined in four different treatments represented by low or high FD and PD; these treatments present different scenarios of trait evolution and, therefore, a treatment with high FD and low PD, for instance, mimics a community assembled by divergent trait evolution of close relatives. We found that leaf decomposition was 30% slower in pools with high FD and PD. We show species pool with higher FD and PD have non-additive effects on decomposition, which means there is a negative effect of mixtures combining species with great functional and evolutionary differences. In addition, interactive effects of PD and FD were more important to leaf decomposition than their isolated effects. Our results suggest that PD and FD have interactive effects on decomposition and represent different axes of ecosystem variation, indicating we should avoid using phylogenies as a proxy for functional diversity. We argue that future BEF experiments may alter their design by considering a multifaceted scenario investigating community effects on ecosystem functioning, and idiosyncratic effects of key traits which may determine community assembly and ecosystem processes.