Abstract
Mangrove forests represent one of the most productive ecosystems in the world and provide important ecologic and economic value to coastal communities (Lewis 2005; Calhoon and Hensel 2002; Kairo et al. 2001). When disturbed, recovery is not a straightforward process; rather it is determined by disturbance duration, intensity, and frequency (Ellison and Farnsworth 2001; Shugart 1984). In some cases where recovery is delayed or not possible, restoration may be a viable option (Lewis and Streever 2000). This study evaluates post disturbance mangrove restoration using two restoration techniques and trained volunteer helpers. The restoration assessment was conducted in Charlotte Harbor, Florida along a linear shoreline that was heavily damaged when category 4 Hurricane Charley made landfall in 2004. Six research questions were evaluated: (1) Does restoration result in a greater density of established seedlings over natural recovery? (2) Will differences in restoration technique used result in a difference in density of established seedlings? (3) What are the spatial dynamics to recovery? (4) What are the temporal dynamics to recovery? (5) What is the effect of predation on recovery? and (6) Does volunteer training lead to increased knowledge, understanding and confidence regarding mangrove condition and restoration project? Four replicate regions, each subdivided into three treatments, were evaluated. Treatments included hand planting, dispersal of propagules and no treatment (control). Treatments were monitored quarterly for one year by quantifying total number of seedlings established and the density of crab holes present (a proxy for crab density) in monitoring plots for each treatment within each region. The number of seedlings that were eventually established using the dispersal treatment was significantly greater than those resulting from control, but not from those hand planted. No significance was found between hand planting and the control. This study documented differences in seedling establishment between regions along the north-south gradient; however, only two regions differed significantly from one another. No significant relationship between the number of crab holes and seedling densities were identified, although considerable predation was noted throughout the study. Volunteers were assessed before and after required pre-restoration training to evaluate knowledge gain relative to the project. Knowledge gain was significant in all areas measured. This study establishes a foundation both for using volunteers in post hurricane mangrove recovery and for considering dispersal of propagules as a viable restoration technique. The results indicate dispersal of propagules did increase seedling recovery over natural recruitment. This is an important resource management finding because it provides a cost-effective and minimal-labor alternative to traditional hand planting in mangrove restoration projects.
