COMMUNITY AND PHYLOGENETIC STRUCTURE OF REPRODUCTIVE TRAITS OF WOODY SPECIES IN WET TROPICAL FORESTS

Abstract

We compare the distribution of reproductive traits in woody vegetation of 10 wet tropical forests in northeastern Costa Rica.Based on quantitative sampling of seedlings, saplings, and trees, we assess whether particular sexual systems, pollination syndromes, or seed-dispersal modes are associated with successional stage, prior selective logging, woody growth forms, or patterns of abundance or rarity.We further examine the phylogenetic structure of these traits in the regional woody flora, testing explicit hypotheses regarding phylogenetic clustering of reproductive traits and habitat distributions.Animal dispersal and insect pollination predominate across all forest types and size classes.In second-growth trees, relative abundance of species with explosive dispersal, hermaphroditic flowers, and insect pollination is higher, and relative abundance of species with animal dispersal and mammal pollination is lower, compared to old-growth and logged forests.Overall, dioecy and wind dispersal are more frequent than expected in canopy trees, and hermaphroditic flowers are more frequent than expected in shrubs.Reproductive traits, growth-form traits, and relative abundance patterns show significant clustering within the supertree phylogeny.Patterns of trait distribution across forest types are closely linked with patterns of floristic composition at the genus and family level.Species-level associations among reproductive traits and woody growth form can be explained by phylogenetic correlations.Wind dispersal and hummingbird pollination are significantly concentrated in clades with hermaphroditic flowers, whereas wind pollination is concentrated in clades with unisexual flowers.Legacies of both phylogenetic history and forest disturbance structure the distribution of reproductive traits within and among tropical wet forest communities.