Riparian management affects instream habitat condition in a dairy stream catchment

• Published in: New Zealand journal of marine and freshwater research Vol. 50; no. 4; pp. 581 - 599
• Main Authors: Holmes, R, Hayes, J, Matthaei, C, Closs, G, Williams, M, Goodwin, E
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 01.10.2016; Taylor & Francis Ltd
• Subjects: Dairy; fine sediment; fish habitat; Freshwater; GIS; Marine; riparian management; Sediments; stock exclusion; PSE, New Zealand
• ISSN: 0028-8330; 1175-8805
• DOI: 10.1080/00288330.2016.1184169

Using a space-for-time substitution design, we investigated the response of structural instream habitat and fish populations to different riparian management practices throughout a Dairy Best Practice Catchment. We found a significant negative correlation between the upstream area of stock exclusion fencing and deposited instream fine sediment cover. Furthermore, we determined that this relationship emerges when ≥300 m lengths of upstream riparian area were included in the analysis, indicating the scale at which stock exclusion fencing results in a positive instream habitat response. Specifically, for this historically degraded spring-fed stream, our findings indicate that riparian segments with 5 m wide stock exclusion fences (both banks) are required to achieve instream fine sediment cover below 20% in downstream reaches. Fish were sparse and evenly spread throughout the catchment. Fish distributions were not correlated with reach-scale riparian or instream habitat variables, possibly because the available habitat quality gradient was too narrow.