The effects of forest fragmentation on stream invertebrate communities on Banks Peninsula

Type of content
Theses / Dissertations
Publisher's DOI/URI
Thesis discipline
Zoology
Degree name
Master of Science
Publisher
University of Canterbury. Biological Sciences
Journal Title
Journal ISSN
Volume Title
Language
Date
2006
Authors
Fraser, Iain
Abstract

The removal of indigenous forest and associated fragmentation of habitats has probably had significant impacts on the diversity of stream communities in New Zealand. In this study I investigated the effects of forest fragmentation on stream invertebrate communities on Banks Peninsula. Six catchments were investigated, three with continuous indigenous forest in the riparian zone and three with fragmented indigenous riparian forest. An extensive benthic survey was conducted at three sites in each river catchment, one downstream on the mainstem of the river and two sites in different headwater tributaries. Adult sampling, consisting of malaise and sticky trapping, was also conducted at a sub-set of sites. Taxonomic richness of both the benthic and adult communities was significantly higher in continuous forest than in fragmented forest, and the composition of benthic communities also differed between continuous and forest fragments. Furthermore, benthic invertebrate densities were higher in fragments than continuous forest sites. The fragments in the headwaters were more likely to support forest specialist taxa (e.g. the stonefly Zelandobius wardi, and the caddisfly Costachorema peninsulae), than the downstream fragments. My results indicate that forest fragmentation has resulted in marked changes in benthic communities on Banks Peninsula, and that location of the fragment within the catchment also is important in influencing the diversity and composition of benthic communities. The maintenance of indigenous forest in the headwaters of streams may be essential for the persistence of endemic and forest specialist taxa on Banks Peninsula.

Description
Citation
Keywords
Stream communities, forest fragmentation, biodiversity
Ngā upoko tukutuku/Māori subject headings
ANZSRC fields of research
Rights
Copyright Iain Fraser