Reproduction and recruitment of Rhizophora mangle (Red Mangroves) in Charlotte Harbor following hurricane Charley
Proffitt, C.E., E.C. Milbrandt, and S.E. Travis
Published In 2006
Estuaries and Coasts 29:972–978
Reproductive aspects of life history are known to be important in recovery following disturbance in many
plant species although this has not been well studied in mangroves. Hurricane Charley devastated large areas of mangroves in Charlotte Harbor, Florida, in August 2004. We surveyed 6 forests in Charlotte Harbor (2002, 2003, and 2005) and 16 in Tampa Bay, Florida (2001, 2002, 2003, and 2005) for total numbers of reproducing trees and trees heterozygotic for albinism that produce both normal and albino propagules. Tree size (estimated height and diameter at breast height) was also recorded for sentinel heterozygotic trees. Total number of reproducing trees km-1 was used as an index of reproductive
output of the population, and deviation from the 3:1 (normal:albino propagules) ratio on heterozygotic trees expected with 100% selfing was used to estimate outcrossing. Numbers of Rhizophora mangle reproducing trees km-1 of shoreline in Charlotte Harbor were reduced by an order of magnitude following Hurricane Charley, while numbers of reproducing trees in Tampa Bay were similar to those of previous years. Reduced reproduction in Charlotte Harbor was accompanied by fewer new recruits in plots on Sanibel and Captiva Islands. Numbers of new recruits after the storm also tended to be fewer in plots where canopy loss was greater. More new recruits occurred in sites that had higher densities of pre-storm Rhizophora seedlings and greater relative dominance by Rhizophora. Outcrossing of sentinel trees was 2.5 times greater in Charlotte Harbor (mean site21 5 33.6 6 6.7%; with 17% of forest sites completely selfing) than in Tampa Bay (mean site-1 = 13.4 ± 4.7%; with 40% of sites completely selfing), although the implications for seedling recruitment of this difference are not known.