Macroinvertebrates associated with various aquatic macrophytes in the backwaters and lakes of the upper Clutha Valley, New Zealand

Abstract

The invertebrate communities associated with 3 native aquatic macrophytes (Potamogeton cheesemanii, Myriophyllum propinquum and Characeae) and 3 adventive species (Elodea canadensis, Lagarosiphon major, and Ranunculus fluitans) in Lakes Wanaka and Roxburgh and several backwaters of the Upper Clutha River were studied in February‐March 1980. Underwater divers obtained a total of 24 × 1 m² macrophyte samples, from which the invertebrates were removed. 26 invertebrate taxa were identified, several of which had not previously been recorded from macrophyte communities in New Zealand. The communities were all dominated by the gastropod Potamopyrgus antipodarum, with Physa sp. (Mollusca) or Chironomidae (Diptera) being sub‐dominant. Overall, the mean abundance of invertebrates was 1585 m^‐2 , and the mean biomass of invertebrates was 0.994 g m^‐2. The Characeae had the highest mean abundance and biomass of invertebrates, and P. cheesemanii the lowest. Significant differences in invertebrate abundance and biomass occurred between some of the macrophyte habitats, but there appeared to be no preference by the invertebrate fauna for either indigenous or adventive macrophyte species as a habitat.