Influence of flooding and vegetation patterns on aquatic beetle diversity in a constructed wetland complex

Abstract

We tested wetland-restoration management techniques to restore and increase the diversity of aquatic beetle assemblages. Three wetland treatments were examined that included: (i) unplanted surface flow (unplanted SF) wetland, (ii) surface flow (planted SF) wetlands planted with aquatic plants, and (iii) subsurface flow (SSF) wetlands. Species richness of aquatic beetles in SF wetlands was highest in spring, while the abundance was lower in the planted SF wetlands than in the unplanted SF wetland. Planted SF wetlands had a slightly higher diversity of beetles than that of the unplanted SF wetland. The planted and unplanted SF wetlands had similar attributes throughout the rest of the year. In SSF wetlands, beetles were significantly more abundant and species rich in spring than either in the planted or in the unplanted SF wetlands. Beetle diversity in SSF wetlands was higher than that in SF wetlands. During the summer, the differences between treatments disappeared. Our results suggested that: (i) vegetation planting was a successful wetland restoration technique, due to the increased habitat diversity, (ii) subsurface flooding provided fishless temporary waters with favorable breeding conditions for aquatic beetles, thus it was also a useful restoration technique, and (iii) significant seasonal differences in abundance and species richness reflected the characteristic breeding habits of aquatic beetles.