Exotics and Hurricane Damage in Three Hardwood Hammocks in Dade County Parks, Florida
Horvitz CC, McMann S, Freedman A. 1995. Exotics and Hurricane Damage in Three Hardwood Hammocks in Dade County Parks, Florida. Journal of Coastal Research (JCR). (Special Issue No. 21):145-158
Frequent hurricane disturbance is a normal part of the ecology of southern Florida. However, the ecological consequences of Hurricane Andrew (August 24,1992) for the hardwood hammock pre serves of Dade County may be quite distinct from the effects of previous hurricanes, because these forests contained and were surrounded by a landscape far more abundant in exotic vegetation than previously. The exotics seemed poised to occupy the regeneration niches opened by Hurricane An drew. To study the effects of exotics on the regeneration process, we set up four 30 x 60 m long term plots in each of three hardwood hammock preserves, at Matheson Hammock, Deering Estate, and Castellow Parks. These hammocks were different distances from the center of the hurricane. The study plots included areas that had light to moderate exotic vinecover before the hurricane. Four months after the hurricane, we measured the canopy disturbance/regeneration (using fish eye canopy photographs). The hammock located north of the eyewall of the hurricane (Matheson) suffered one-half the canopy disturbance compared to the hammocks traversed by the northern eyewall (Deering and Castellow). Eight months after the hurricane, we measured, counted and tagged the vegetation in sub-plots for long-term study, recording species, type of damage, sur vival, and size of plants. Damage varied significantly by life form, by tree size and by hammock. Trees suffered more damage than shrubs or vines. Large trees suffered more damage than smaller trees and the hammock at the inner edge of the eyewall suffered more damage than the others. Over one-third of the plant species in these hammock study plots were exotic. The exotic tree spe cies Carica papaya varied in its importance among the hammocks, recruiting rapidly and abun dantly from a seed bank; where present, it created canopy within four months, perhaps negatively impacting native pioneer tree species. Exotic vinecover also varied significantly among the ham mocks (Matheson, Deer
- Type
- Journal Article
- Authors
- Horvitz, Carol; McMann, Stephen; Freedman, Andrea
- Units
- JELA
- Keywords
- andrew, Canopy, Carica, Disturbance, Exotic, Florida, Forests, hammocks, hardwood, Hurricane, invasions, jasminum, Miami, papaya, ridge, Rock, southern, Subtropical