Hurricane Andrew and Upland Forest Succession in Biscayne National Park

Ross, Michael; Telesnicki, Guy; Ruiz, Pablo; Flynn, Laura

A tree species replacement sequence for dry broadleaved forests (tropical hardwood hammocks) in the Florida Keys was inferred from species' abundances in a series of stands abandoned from agriculture or other anthropogenic acitivities at different times in the past. Using a weighted averaging regression procedure, species' positions within the sequence were then used to analyze within-stand structure in two forests impacted by Hurricane Andrew in Biscayne National Park. Species characteristic of the earliest stages of post-agricultural stand development remain a significant component of the forest for many years, but are gradually replaced by taxa not present, even as seedlings, during the first few decades.This compositional sequence of a century or more in length is characterized by the replacement of deciduous by evergreen species, which is hypothesized to be driven by increasing moisture storage capacity in the young organic soils. Despite passing directly over Biscayne National Park, Hurricane Andrew created limited opportunities for the successful establishment of early-successional species. Establishment of pioneers like Solanum bahamense, Guettarda elliptica, Bourreria ovata, and Piscidia piscipula were largely restricted to large openings in the older of the two stands examined. Geostatistical analyses indicated that the same stand also exhibited a spatial structure in Inferred Successional Age, which was interpreted to result from a long history of partial disturbances similar to the most recent hurricane.