Colonization of non-planted mangrove species into restored mangrove stands in Gazi Bay, Kenya

Recruitment of non-planted mangrove species into Rhizophora mucronata, Sonneratia alba and Avicennia marina reforested stands (all of them 5 years old) was investigated to assess possibilities for natural colonization. Corresponding bare (denuded or open without mangroves) and natural (relatively undisturbed) sites were used as controls. Interstitial water salinity and temperature (measured at low tide) were lower, whereas sediment organic matter content was higher in the areas with mangrove cover. Also, the bare sites were more sandy, whereas those with mangrove cover had more clay and silt. There was no apparent recruitment of non-planted mangrove species into the bare areas, but the reforested stands of S. alba, A. marina, and R. mucronata had 5400, 4000 and 700 recruits ha-1, respectively of different mangrove species. The results therefore suggest that mangrove reforestation has facilitated natural colonization of sites, most likely by altering local hydrodynamics