The objective of this project was to compile a dataset on stream and riparian functioning condition in Vanderhoof Forest District?s unmanaged forests in order to provide a baseline reference for effectiveness monitoring comparisons, and more specifically, for those indicators listed in the BC Forest and Range Evaluation Program?s Riparian Management Routine Effectiveness Evaluations (RMREE). The call for this study arose from the history of repeated downgrading of the functioning condition of harvested reaches that could be attributed to fine sediment, and the suggestion that similar conditions existed at unmanaged reaches. This project set out to quantify natural conditions and statistically relate these to harvested sites so that the end result would more accurately reflect impacts due to harvesting.
After the field data collection and analyses phases were completed, a number of MS Excel spreadsheets were created with embedded calculations to effectively predict new threshold values for attributes that were thought to be influenced by the natural occurrence of fine sediments in the Vanderhoof Forest District. The indicators represented by these attributes include:
1) fine sediments,
3) fish cover,
4) moss, and
5) aquatic invertebrate diversity.
The calculations created for predicting threshold values were based on relationships between the attributes and physical site characteristics at non-harvested reaches. The site characteristics included:
1) soil erodibility,
2) channel width,
3) channel gradient,
5) elevation, and
6) hillslope (coupling).
Data from 31 MoFR sites that had been previously classified as functioning at risk, functioning at high risk, and not properly functioning were re-assessed using the new threshold values specific to each site. Results suggest an upgrade in the functioning condition for 29% of the sites, and a
downgrade in 6% of the sites. The upgraded sites were recommended because the harvested attribute data for the fine sediment, moss, and fish cover indicators fell within the range of natural variability as judged by the new threshold values. The downgraded sites were mainly a result of new higher thresholds for three of the aquatic invertebrate attributes. Field data could not meet these thresholds in several of these cases, resulting in an overall increase in negative responses for the aquatic invertebrate indicator. While this change could represent a more accurate reflection of harvesting impacts, it also may be a result of seasonal variation in flow and related processes between the non-harvested and harvested sampling events.
Avison Management Services Ltd.. 2010. Improving a standard monitoring protocol for use in Central-Interior British Columbia. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2010MR157
Topic: FLNRORD Research Program
Keywords: Forest, Investment, Account, (FIA), Land, Base, Investment, Program
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