The role of mangrove revegetation as a means of restoring macrofaunal communities along degraded coasts

Abstract

As coastal habitats face unprecedented pressure globally, there is a need to better understand how revegetation can fortify or restore biodiversity. We examined the early-stage outcomes of mangrove revegetation efforts for benthic invertebrate communities within degraded mangrove habitats in south eastern Brazil. We followed changes in macrofaunal abundance and species richness within small-scale Avicennia schaueriana revegetation plots over a 12month period. The assemblages of revegetation plots (RP) became progressively more diverse when compared to structural (SC) and blank controls (BC). The trajectory of change also differed with RP communities demonstrating convergence with those of remnant mangrove forest. After 12months, RP had greater abundances of crustaceans (41%) and polychaetes (13%) as well as higher but variable numbers of gastropods and bivalves than both SC and BC. A spatial examination of revegetation outcomes showed that success may vary across sheltered vs. exposed coastal microhabitats. Indeed, subsequent analysis using generalised linear mixed models pointed to a stronger influence of tidal height, than many of the commonly attributed sedimentary variables such as grain-size and organic matter content as determinants of community structure. Given the encouraging results of this study, we advocate an intensification of revegetation initiatives to augment natural recovery, increase benthic biodiversity and restore ecosystems services to degraded coasts.