Correlation of variations in species abundance of Atlantic forests regenerating on abandoned pastures with different environmental and spatial variables

Abstract

The conversion of native forests into pastures is still a common practice in Brazil. Abandoned pastures have great potential for natural regeneration  and therefore could play an important role in meeting the enormous demand for forest restoration. Few studies, however, have investigated the  extent to which spatially-structured environmental variables and community structure are correlated with the variation in species abundance of  regenerating forests on abandoned pastures. Therefore, we aimed to determine whether environmental and spatial variables were capable of  explaining the variation in abundance of woody species on abandoned pastures in the subtropical Atlantic Forest. We systematically distributed 45  sample plots with size and inclusion criteria that changed according to the vegetation layer in three different abandoned pastures. In general, most  of the variation in species abundance that our models were able to explain was correlated with spatially-unstructured physical-chemical soil  properties. A smaller part of the variation was correlated with spatially-structured soil variables and topography-related variables. An even smaller  portion of the variation was spatially-structured but was not correlated with spatially-structured environmental variables. Therefore, our results  suggest that the variation in species abundance of regenerating subtropical Atlantic forests on abandoned pastures is more closely related to niche- based processes mediated by environmental variables  than to stochastic spatial processes.