Changes in Phylogenetic Community Structure of the Seedling Layer Following Hurricane Disturbance in a Human-Impacted Tropical Forest

Jimena Forero-Montaña,W. Kress,Jess Zimmerman,Jill Thompson,Nathan Swenson,Liza Comita,María Uriarte,María Umaña

doi:10.3390/f9090556

Abstract

Disturbance plays a key role in shaping forest composition and diversity. We used a community phylogeny and long-term forest dynamics data to investigate biotic and abiotic factors shaping tropical forest regeneration following both human and natural disturbance. Specifically, we examined shifts in seedling phylogenetic and functional (i.e., seed mass) community structure over a decade following a major hurricane in a human-impacted forest in Puerto Rico. Phylogenetic relatedness of the seedling community decreased in the first five years post-hurricane and then increased, largely driven by changes in the abundance of a common palm species. Functional structure (based on seed mass) became increasingly clustered through time, due to canopy closure causing small-seeded, light-demanding species to decline in abundance. Seedling neighbor density and phylogenetic relatedness negatively affected seedling survival, which likely acted to reduce phylogenetic relatedness within seedling plots. Across the study site, areas impacted in the past by high-intensity land use had lower or similar phylogenetic relatedness of seedling communities than low-intensity past land use areas, reflecting interactive effects of human and natural disturbance. Our study demonstrates how phylogenetic and functional information offer insights into the role of biotic and abiotic factors structuring forest recovery following disturbance.

Highlights

Disturbance plays a key role in shaping ecological communities by increasing spatial and temporal variation in resource availability and providing opportunities for recruitment [1,2]
We found significant variation in phylogenetic structure among years, as seen in Figure 1, for both indices
In addition to impacts of natural disturbance on phylogenetic community structure, we found that the phylogenetic structure of the seedling community differed significantly between areas that had experienced different intensities of past human disturbance

Summary

Introduction

Disturbance plays a key role in shaping ecological communities by increasing spatial and temporal variation in resource availability and providing opportunities for recruitment [1,2]. Species often differ in their responses to disturbance, employing divergent strategies that allow them to take advantage of heterogeneous environmental conditions [3,4]. This variation in life history strategy is hypothesized. If there is phylogenetic signal in the traits that underlie species life history strategies in response to disturbance (e.g., related species have more similar strategies than expected by chance), disturbance will leave a signature on species composition, and on the phylogenetic structure of the community [8]. A number of studies have investigated effects of anthropogenic disturbance on phylogenetic patterns of plant community composition (e.g., [11,12,13,14,15,16]). Previous studies suggest that human disturbance often results in increased phylogenetic relatedness (i.e., decreased phylogenetic diversity) in forest communities

Methods

Results

Conclusion