Application of taxonomic distinctness indices of littoral macroinvertebrate communities for assessing long-term variation in ecological quality status of intertidal ecosystems, northern China.

It has been increasingly recognized that taxonomic diversity indices have a number of desirable properties as an indicator for assessing ecological quality status, in particular their less sensitivity to natural habitat type and sampling effort but more to environmental stress and anthropogenic impact, and a statistical framework for the assessment of the significance of departure from expectation. Taxonomic patterns of macroinvertebrate fauna for assessing ecological quality status were studied based on six datasets collected from intertidal zones of the Yellow Sea, near Qingdao, northern China, during the period of 1989-1998. The invertebrate communities were sampled yearly at five stations with different bottom types during summer season (June). A total of 141 macroinvertebrate taxa were identified belonging 119 genera, 81 families, 34 orders, 19 classes, and 10 phyla. Multivariate analyses demonstrated that the taxonomic patterns of invertebrate fauna represented a significant variation in long-term temporal scale during the study period. The average taxonomic distinctness indices (Δ(+)) decreased to a significantly low level, while the variation in taxonomic distinctness measures (Λ(+)) increased to a significantly high level compared with the expected values from 1989 to 1998. The pairwise indices of Δ(+) and (Λ(+)) showed a decreasing and increasing trend of departure from the expected taxonomic breadth in response to the environmental stress and anthropogenic impact, respectively. These results imply that the ecological quality status has been significantly deteriorated due to the increasing environmental stress and anthropogenic impact in intertidal zones of the Yellow Sea, northern China, and that the taxonomic distinctness indices of macroinvertebrate fauna are a robust indicator for evaluating ecological quality status.