Completing the life history of Castanopsis fargesii: changes in the seed dispersal, seedling and sapling recruitment patterns

Abstract

The spatial distribution of species in forest ecosystems involves the underlying ecological processes or mechanisms of population and community structure, as well as forest dynamics. Because the relative importance of these factors can shift across life history stages, assessment of local population and community structures in the context of life history stages is essential for understanding forest dynamics. In this study, we investigated the changes in the spatial patterns of seed dispersal as well as seedling and sapling recruitment for Castanopsis fargesii, a dominant tree species in a subtropical evergreen broad-leaved forest in China. We found notably aggregated spatial patterns for C. fargesii seeds during the seed dispersal. A majority of seeds and newly germinated seedlings aggregated under adult tree canopies, suggesting a decreased efficiency in secondary dispersal for C. fargesii within this evergreen broad-leaved forest. During the later stages of life history (i.e., seedling and sapling stages), the spatial distribution of C. fargesii getting segregated. This is caused by a negative density dependence mechanism in seedling recruitment, rather than by spatial dispersion due to secondary dispersal. By incorporating the patterns and processes across the life history stages of dominant species of evergreen broad-leaved forests, we can add specific details in developing methods of stage-based in situ forest management and conservation frameworks.