Although most fish-forestry research has been conducted in coastal areas, the bulk of the world?s timber supply for the immediate future will be from interior forests. Studies documenting the impacts of forest practices on small streams in these regions are rare, and this proposal seeks to address this gap in our knowledge. Our proposed research will nearly double the time frame over which post-logging observations are made on a set of experimentally logged interior streams. This is extremely important as many post-logging effects to streams are not evident until 10+ years. Specifically, 3 small, lake-headed S3 streams were monitored prior to (1997) and following (1998-1999, 2004) streamside logging (total post-logging observations of 6 years). The logging treatments applied to the streams were novel, allowing for the removal of all commercial timber within the riparian reserve zones while retaining non-commercial coniferous trees and deciduous vegetation. Such a prescription actually violated the Forest Practices Code of the day, but under the present Forest Practices and Range Act, it would be allowed and is presently being used. Also, they mimic aggressive riparian salvage logging now occurring due to mountain pine beetle (MPB) infestations, and our proposal would provide the only longer-term assessment of fish/habitat from MPB logging practices in north-central BC. The proposal extends data collection to 10 yrs post-harvest and builds on our previous FRBC, FII, FSP projects conducted in northcentral BC. To date we have found: a) Logging reduced streamside canopy cover by 50% - the remaining streamside vegetation continued to provide shade and future supply of large instream wood. b) Stream temperature changes following logging were relatively modest (< 1 C on average) when compared to headwater streams (5-7 C). c) Logging treatments did not cause detectable changes in rainbow trout movement patterns, whereas trout growth was greater in the logged streams than in the control stream (which we attributed to earlier emergence from stream gravels and a more conducive thermal environment). d) Post-logging summer suspended sediment levels remained low, and average summer dissolved oxygen (DO) concentrations remained above the level required for salmonids to function without impairment. e) The number of pools was unaffected, and reductions in pool area and volume of approximately the same magnitude were observed in both the treatment and control streams. f) Rainbow trout densities and biomass were variable across years, with > 90% of the populations in both streams comprising young-of-the-year (YOY) and age 1 ? 2 trout. The above results provide much needed information on stream ecosystem responses to logging practices in interior regions, but it only provided a relatively short-term (1-6 years) post-logging perspective. Although many habitat and fish measures were not affected in the short-term, theoretical models indicate that we might expect to find significant changes 10+ years post-logging. In this proposal, we seek to re-visit the same 3 lake-headed streams monitored in our previous studies in order to assess longer-term (10 years) responses to the logging treatments. Case study field experiments (that incorporate before and after assessments) which examine the effects of streamside harvesting on small stream ecosystems are rare in coastal regions, but they are virtually non-existent in temperate interior regions and none focus on lake-headed streams (which are abundant in boreal and sub-boreal landscapes). Our previous results underscore the natural variability inherent in small stream ecosystems, and highlight the need for multi-disciplinary and long-term research to better understand the impacts of streamside clear-cut logging. This project will establish the first long-term, before and after logging, fish-forestry case study (> 10 years, the equivalent to 3 full generations of rainbow trout) in temperate, interior re ...
Hinch, Scott G.. 2008. Long-term stream habitat and rainbow trout responses to alternative riparian management in north-central British Columbia. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2008MR088
Topic: FLNRORD Research Program
Keywords: Forest, Investment, Account, (FIA), British, Columbia
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