Functional structure of an herbaceous community on a natural regeneration gradient in a seasonally dry tropical forest

Abstract

The capability of plants to modify phenotypic characteristics through interactions with the environment can contribute to functional stability, particularly when this plasticity influences traits associated with survival, rendering it a pivotal mechanism for adaptation. Grime's CSR theory is employed to classify plants based on functional traits dictating competitive, stress, and ruderal tolerance strategies, as these traits serve as indicators of plant responses to environmental stimuli. This study examines the variation in plant functional traits (morphophysiological and phytochemical) within herbaceous communities across a chronosequence of natural regeneration after land-use alteration and abandonment. We investigate whether a correlation exists between regeneration duration and community-weighted mean values through principal component analysis and canonical correspondence analysis. Intraspecific variability of traits is assessed using one-way ANOVA and Tukey's post-hoc test at a significance level of 5% for mean comparisons. Generally, with progressing regeneration, intraspecific differences emerge, including elevated carbon:nitrogen ratio, phenolic compounds, and carbon assimilation, alongside reductions in leaf area, plant height, leaf succulence, individual biomass, and leaf nitrogen content. Consequently, pasture and initial regeneration communities harbor species with functional traits akin to ruderal species, whereas species inhabiting later stages exhibit traits associated with competitors. Analysis of intraspecific variation demonstrates that species occupying sites at different regeneration stages exhibit phenotypic plasticity. The findings underscore how alterations in environmental conditions during natural regeneration influence functional trait values, and underscore the utility of CSR theory for quantifying, comparing, and predicting community structure based on adaptive plant strategies.