Community-level differentiation of Grime's CSR strategies along a post-abandonment secondary successional gradient

Abstract

Understanding the ecological processes and the mechanisms of community assembly during secondary succession of vegetation has been a central topic of ecological research. In the last decades, it has also been rendered as a necessity for wildlife management due to the ongoing vegetation succession caused by land abandonment in many parts of the world. Here, we investigated the taxonomic and life strategies diversity patterns among vegetation communities representing a large part of a natural succession gradient, in a (sub-) mountainous area of northwestern Greece (northern Pindus). Sampling of grassland and forest vegetation plots was conducted across an area submitted to high levels of land abandonment during the last 70 years, accompanied with sampling of new functional trait data. The Grime's CSR model of plant strategies was employed to investigate functional diversity of communities, while climatic, edaphic and topographic factors were employed to identify potential drivers of alternative life strategies diversity. Additionally, alpha and beta taxonomic and life strategies diversity of communities were calculated. Variation partitioning analyses attributed functional and taxonomic differentiation of communities mainly to the legacy of land use cover. Overall, grasslands and forests were functionally differentiated, with forest communities having higher levels of the competitive strategy, and grasslands having higher levels of the ruderal strategy. Nevertheless, parallel trends of occurrence of plant life strategies were found for both grasslands and forests. Community level competitive and stress-tolerating plant life strategies were found to be strongly and negatively correlated with soil organic content, soil nitrogen, soil pH and slope, while ruderalism was largely related to the disturbance regime of each community. The derived information of functional strategies diversity can provide valuable data that can guide management actions and contribute to the optimization of systematic conservation planning in such high nature value and threatened ecosystems.