Publication: Aquatic invertebrate communities of lowland wetlands in New Zealand

[Dave Houston]

Aquatic invertebrate communities of lowland wetlands in New Zealand: characterising spatial, temporal and geographic distribution patterns
By A. Suren and B. Sorrell
Science for Conservation 305, 64 p.

What's it about?
This report documents the aquatic invertebrate communities of lowland wetlands throughout New Zealand. It addresses three questions: how do communities vary within and between wetlands; to what extent do communities vary temporally; and how are communities affected by environmental variables? Invertebrate collections from 40 wetlands showed that the fauna was dominated by midges (Chironomidae), aquatic mites (Acarina), Copepoda, Nematoda and Ostracoda. The mud snail Potamopyrgus antipodarum and the damselfly Xanthocnemis zealandica were also common. A detailed survey of the open-water habitats of two acidic fens and two swamps showed that invertebrate communities varied more between wetlands than they did within wetlands, presumably reflecting differences in water chemistry between fens and swamps. Thus, it may not be necessary to sample specific habitats or plants within wetlands to accurately characterise their invertebrate communities, as long as the range of habitat types is covered. Similarly, analysis of annual data collected at one wetland and of seasonal data collected at two wetlands showed that although invertebrate communities varied temporally, the degree of this variation was small compared with differences within or between wetlands. Thus, wetland invertebrate surveys may not be particularly sensitive to the time of sampling, as community composition is driven by large-scale factors that influence water chemistry and that override temporal changes in the relative abundance of some taxa. Finally, a survey of 40 wetlands throughout the country showed that invertebrate communities are controlled mainly by biogeography, followed by water chemistry—particularly pH. This finding has management implications, as regionally based conservation goals may need to be considered instead of setting goals for specific wetland types.

The above new publication is now in press and can be downloaded from:
http://www.doc.govt.nz/upload/documents/science-and-technical/sfc305entire.pdf (1102 KB)