Factors influencing early secondary succession and ecosystem carbon stocks in Brazilian Atlantic Forest

Ecologically relevant restoration of secondary Atlantic forest on abandoned land offers a potential means to recover biodiversity and improve crucial ecosystem services, including carbon sequestration. Early secondary successional trajectories are determined by a range of environmental factors that influence plant community development. Context-specific understanding of forest vegetation communities, their dynamics, and underlying drivers is needed for future restoration strategies. In this study we examined relationships between soil (chemical and physical) and environmental (landscape and topographical) characteristics, plant community attributes, and carbon stocks during early secondary succession. Data were collected at two sites undergoing early secondary succession in seasonally-dry Atlantic Forest (Rio de Janeiro State, Brazil). Both sites were previously used for pasture and abandoned at similar times, but showed differing vegetation communities. We found tree biomass and diversity and ecosystem carbon storage to be strongly positively related to the amount of surrounding forest, less steep slopes and clay soils, and negatively to the abundance of the shrub Leandra aurea. Soil carbon pools significantly increased with aboveground tree biomass. The only factor significantly affecting the metric of overall successional development (combining tree biomass and diversity) was total surrounding forest cover. Our findings suggest recovery of secondary forest and below- and aboveground carbon storage is limited by the amount of adjacent forest, some soil properties and dense shrub establishment down-regulating the succession process. Overall we offer evidence of potential to improve recovery of Atlantic forest with ecologically relevant seeding/planting programmes and selective shrub removal that could benefit ecosystem carbon storage.