Woody Debris in the Mangrove Forests of South Florida

Authors

Ken W. Krauss, U.S. Geological Survey, National Wetlands Research CenteFollow
Thomas W. Doyle, U.S. Geological Survey, National Wetlands Research CenteFollow
Robert R. Twilley, Center for Ecology and Environmental Technology, Department of Biology, University of Louisiana at LafayetteFollow
Thomas J. Smith III, U.S. Geological Survey, Center for Water & Restoration StudiesFollow
Kevin R.T. Whelan, U.S. Geological Survey, Florida/Caribbean Science Center, Biological Sciences Department, Florida International UniversityFollow
Jason K. Sullivan, Johnson Controls World Services, National Wetlands Research CenterFollow

Abstract

Woody debris is abundant in hurricane-impacted forests. With a major hurricane affecting South Florida mangroves approximately every 20 yr, carbon storage and nutrient retention may be influenced greatly by woody debris dynamics. In addition, woody debris can influence seedling regeneration in mangrove swamps by trapping propagules and enhancing seedling growth potential. Here, we report on line-intercept woody debris surveys conducted in mangrove wetlands of South Florida 9–10 yr after the passage of Hurricane Andrew. The total volume of woody debris for all sites combined was estimated at 67 m³/ha and varied from 13 to 181 m³/ha depending upon differences in forest height, proximity to the storm, and maximum estimated wind velocities. Large volumes of woody debris were found in the eyewall region of the hurricane, with a volume of 132 m³/ha and a projected woody debris biomass of approximately 36 t/ha. Approximately half of the woody debris biomass averaged across all sites was associated as small twigs and branches (fine woody debris), since coarse woody debris >7.5 cm felled during Hurricane Andrew was fairly well decomposed. Much of the small debris is likely to be associated with post-hurricane forest dynamics. Hurricanes are responsible for large amounts of damage to mangrove ecosystems, and components of associated downed wood may provide a relative index of disturbance for mangrove forests. Here, we suggest that a fine:coarse woody debris ratio ≤0.5 is suggestive of a recent disturbance in mangrove wetlands, although additional research is needed to corroborate such findings.

Comments

This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Recommended Citation

Krauss, K.W., T.W. Doyle, R.R. Twilley, T.J. Smith, K.R.T. Whelan, J.K. Sullivan. 2005. Woody Debris in the Mangrove Forests of South Florida. Biotropica 37(1): 9-15.