Changes of macro-benthic faunal community with stand age of rehabilitated Kandelia candel mangrove in Jiulongjiang Estuary, China

Distribution properties of macro-benthic faunal communities were compared among rehabilitated Kandelia candel forests of different ages in Jiulongjiang Estuary, China. From July 2005 to April 2006, seasonal surveys were conducted within four representative forests—K4, K7, K19 and K43, with ages of 4, 7, 19 and 43 years, respectively. Two non-vegetated flats (NF1 and NF2) were set as the references. Numbers of faunal species in rehabilitated forests were higher than NF1 and NF2, while younger forests (K4 and K7) generally had more macro-benthic fauna species than older ones (K19 and K43). Among the total 24 species recorded, Uca arcuata, Metaplax elegans, Phascolosoma esculenta and Littoraria melanostoma were dominant. Macro-benthic faunal community structures were different among the four rehabilitated K. candel forests. The dominant species in younger forests was M. elegans, while U. arcuata had a higher abundance than M. elegans in non-vegetation flats and older forests. Gastropods were abundant in younger forests. Distribution properties of dominant species differed among rehabilitated K. candel forests. U. arcuata had the largest density in non-vegetated flats, and was infrequent in younger forests. M. elegans had high abundances in younger forests. High abundance of P. esculenta was found in older forests, while L. melanostoma was more abundant in younger forests. Since both macro-benthic faunal community and vegetation were similar in K19 and K43, rehabilitated K. candel mangrove was considered steady 19 years after being planted. That is, in the case of macro-benthic fauna and vegetation, a K. candel mangrove may evolve to a mature state at a stand age of about 20 years.