Hurricane disturbance and forest dynamics in east Caribbean mangroves

Abstract

Despite low plant diversity and structural simplicity, mangroves offer various ecosystem services to local human communities, including sheltering coastal social‐ecological systems from high‐energy storm damage. The expected increasing intensity of hurricanes due to climate change raises questions concerning the capacity of mangroves to resist and recover from such disturbances. Herein, this study contributes to a better understanding of (1) the relation between storm intensity and damage to mangrove vegetation, (2) the contributions of species‐specific as well as stand‐specific components of mangrove vegetation to ecosystem resistance, and (3) the recovery of pre‐hurricane forest structure through time. The first two issues have been addressed using a stand‐level approach implemented at two east Caribbean mangrove sites in response to three storm events. The third was addressed through a 23‐yr survey of forest recovery following the passage of a high‐energy storm across one of the two study sites. Generally, hurricane damage was primarily controlled by wind velocity, followed by the hydro‐geomorphic context of mangrove forests and species‐specific composition, respectively. The relationship between damage to trees and wind velocity evidenced a sigmoidal trend, with a maximum slope at a wind velocity averaging 130 and 180 km/h for higher vs. lower canopy stands, respectively. The red mangrove, Rhizophora mangle, was significantly less resistant to hurricane damage than was the black mangrove, Avicennia germinans. Unlike the fringe and scrub stands, inner, tall‐canopy stands fully recovered by the end of the study (23 yr). These stands were more resilient because of their growth performances. Finally, the time for east Caribbean mangroves to recover from high‐energy storms seems to fall within the range of the average return time of such disturbances. This may prevent such ecosystems from ever reaching a steady state.

Changes in mangrove tree mortality, forest canopy, and aboveground biomass accumulation rates following the 2017 hurricane season in Puerto Rico and the role of urbanization

“…Baldwin et al 2001). Avicennia spp ., however, have repeatedly been found to be of the most resistant species to hurricane disturbance (Woodroffe and Grime 1999; Daniel Imbert 2018), so its failure to regrow in this study is contradictory. It’s possible that because all sites in this study were fringe systems of low A. germinans density (Branoff and Martinuzzi 2018), recovery following the storm was made more difficult by stressful and unsuitable habitat.…”

“…Still another study of the same storm in the Dominican Republic found L. racemosa to be the least affected, and A. germinans (Avicennia germinans) the most (Sherman et al 2001). Other studies for other storms in other locations have found variations in species susceptibilities (Wadsworth 1959; Smith et al 1994; Daniel Imbert 2018). This conflict might be explained by differences in habitat and hydro-geomorphology, both of which have also been found to play a role in storm related tree mortality and forest recovery (Sherman et al 2001; Smith III et al 2009; Daniel Imbert 2018).…”

“…With a mean mortality of 22%, Puerto Rico’s mangrove’s seem to have fared better than those after other storms, whose mortality ranged from 25% to 90% (Craighead and Gilbert 1962; Roth 1992; Smith et al 1994; Armentano et al 1995; Sherman et al 2001; Daniel Imbert 2018). Although this point may be due to differences in survey methodologies, the definition of “mortality”, and/or study lengths between studies, Puerto Rico’s presence at the far lower extreme of this range is notable.…”

“…Recovery patterns show trends within the same predictors of species, size, and geomorphology, again with conflicting conclusions (Roth 1992; A. H. Baldwin et al 1995; Sherman et al 2001; Daniel Imbert 2018). One long-term study of post-hurricane Caribbean mangroves suggest a recovery time to pre-storm similarity of 10-25 years, if at all (Daniel Imbert 2018), and modelling approaches generally agree (Lugo et al 1976; Doyle and Girod 1997).…”

“…H. Baldwin et al 1995; Sherman et al 2001; Daniel Imbert 2018). One long-term study of post-hurricane Caribbean mangroves suggest a recovery time to pre-storm similarity of 10-25 years, if at all (Daniel Imbert 2018), and modelling approaches generally agree (Lugo et al 1976; Doyle and Girod 1997). However, the influence of these disturbances on mangroves is so ubiquitous, that It has been hypothesized they permanently restrict the height of Caribbean mangroves (Odum and Pigeon 1970; Lugo and Snedaker 1974).…”