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Diversity of Adult Aquatic Insects in Hamilton Urban Streams and Seepages

TR 2007/20

Report: TR 2007/20

Author: Brian J. Smith


The adult stages of the aquatic insect groups Ephemeroptera (mayflies), Plecoptera (stoneflies) and Trichoptera (caddisflies) were sampled at nine urban sites to ascertain the invertebrate biodiversity values of small streams and seepages within Hamilton city. A total of 1713 adult mayflies and caddisflies representing 9 families, 16 genera, and 26 species was collected, with caddisflies by far the most abundant group. Sampling of seepages in Hamilton cityscape increased the known aquatic caddisfly biodiversity by over 30 per cent, and included one species new to science. There are now 31 Trichoptera species known as adults from Hamilton city waterways. The maintenance and preservation of vegetated gully systems throughout Hamilton city have helped to protect seepage habitats. Remnant riparian vegetation and bank-side seepages appear to provide refugia and suitable habitats for obligatory native forest and seepage specialists within the city, and therefore the biodiversity of these urban streams is potentially greater than is commonly found in other cities.

Diversity of Adult Aquatic Insects in Hamilton Urban Streams and Seepages [PDF, 262 KB]

  Executive summary iii
1 Introduction 1
2 Methods 2
2.1 Sampling sites 2
2.2 Light traps 3
3 Results and discussion 4
3.1 Abundance and composition 4
3.2 Spatial patterns 4
3.3 Biodiversity and conservation significance 5
4 Summary 7
5 References 8
6 Appendix 9