Post-hurricane regeneration of pioneer plant species in south Florida subtropical hardwood hammocks

After Hurricane Andrew crossed southern Florida (U.S.A.) on 24 August 1932, native and exotic pioneer species in subtropical hardwood forests (hammock s) regenerated from seed banks. Regeneration occurred in hammocks of metrop olitan Dade County and the Long Pine Key region of Everglades National park . The density of the native pioneer Trema micrantha was significantly highe r in hammocks of Long Pine Key than in those of metropolitan Dade County. I n contrast, the basal area of the exotic pioneer Carica papaya was greater in Dade County hammocks than Long Pine Key hammocks. Although T. micrantha tended to be restricted to areas of soil disturbance (tip-up pits) formed b y trees uprooted during Hurricane Andrew, especially in Long Pine Key, C. p apaya was located throughout hammocks. These results suggest differences in the regeneration niches in which the native T. micrantha required more spe cific disruptions (i.e., both canopy and soil) than C. papaya (only removal of canopy) for establishment. A broad regeneration niche could in part acc ount for the capability of an exotic species with a dormant seed bank to in vade native subtropical forests following natural large-scale disturbances.