Abstract:

A survey on macrobenthic assemblages was carried out in the estuary of Dagujia River and its adjacent waters in September 2012 (Yantai, China), to investigate the macrobenthic community and disturbance from anthropogenic activities. The software package PRIMER was used to calculate four biodiversity indices and carry out CLUSTER, non-metric multi-dimensional scaling (MDS) ordination analyses, abundance and biomass curves (ABC) to analyze the community structure. A total of 89 macrobenthic species were identified, of which the dominant group was polychaetes. The average biomass and abundance was 18.02 g/m² and 2,165 ind./m², respectively, of which Molluscan species contributed most to biomass and Crustacean species contributed most to abundance. Three biodiversity indices, Richness index, Evenness index and Shannon-Wiener index were 2.620 ± 1.324、0.585 ± 0.294 and 2.398 ± 1.351, respectively. CLUSTER and MDS analysis showed that macrobenthic assemblages could be divided into five sub-groups based on Bray-Curtis similarity and significant difference was found within the sub-groups. The spatial distribution of abundance and biomass of the community was closely related to water temperature, salt and total phosphorus. ABC curves showed the macrobenthic assemblages suffered disturbance from moderate to severe extent due to anthropogenic activities. Further analysis shows community succession has occurred, seen through a miniaturization tendency of individual body size, and decreasing number of species in assemblages as well as the dominant group changing to Crustacea in the estuary of Dagujia River.

Key words: macrobenthos, community structure, environmental factors, community succession, estuary of Dagujia River and its adjacent water areas