Non-arborescent vegetation trajectories following repeated hurricane disturbance: ephemeral versus enduring responses
Royo AR; Scalley TH; Moya S; Scatena FN
Hurricanes strongly influence short-term patterns of plant community structure composition\nand abundance and are a major contributor to the maintenance of plant diversity in many forests.\nAlthough much research has focused on the immediate and long-term effects of hurricane disturbance on\ntree diversity far less attention has been devoted to the non-arborescent understory community that often\naccount for the vast majority of the vascular species. Using a unique 20 year dataset we tracked changes in\nrichness cover biomass and diversity (H0) of non-arborescent species following Hurricane Hugo (1989)\nand Hurricane Georges (1998) in a mature secondary subtropical wet forest of Puerto Rico. Hurricanes\ncaused an immediate albeit transient increase in overall species richness cover and diversity. Over a\ntwenty year period the non-arborescent community exhibited pronounced and persistent changes in\ncomposition including a dramatic increase in abundance and richness of ferns and vines and a\nconcomitant decrease in forbs and shrubs. By 2010 understory composition and relative abundance\nhierarchies were significantly altered; ferns and vines combined comprised 75 and 90% of total understory\ncover and biomass respectively. Our results for this community contrast sharply with prior studies on\nsimilar temporal and spatial scales that demonstrate hurricanes rarely alter dominant tree species\ncomposition over the long-term. These results suggest that the role of hurricane disturbance in structuring\nplant diversity may be even more important than previously thought.