| Abstract/Description or Keywords |
Forest harvesting in B.C. is moving from prescriptive to outcome based management as development proceeds on various regulatory and product certification systems. To reach this goal, new tools are needed to measure the effectiveness of forest land management practices in sustaining the health of forest ecosystems, including the quality of water that drains those ecosystems. In this project, a bioassessment tool known as the Reference Condition Approach (RCA) was developed for north-central British Columbia. In the RCA, benthic invertebrates and habitat descriptors from a large number of reference sites are used to build a predictive model that allows comparison of a test site with an appropriate reference condition. If the test site falls within the range of natural variability found at reference sites, the site is considered to be not stressed. If the site falls outside of the range natural variability found at the reference sites, the site is considered to be stressed in some way. The greatest value of the RCA is in providing an effective environmental screening tool for land and water management activities. Using benthic invertebrate and habitat descriptions from three years of sampling, two different RCA models were built and compared for potential use in bioassessment in northern British Columbia. The study area extended from the west coast, mainly between Stewart and Kemano, across the Coast Mountains and the Interior Plateau to sites east of Prince George. Sites that were not affected by anthropogenic disturbance were selected for sampling and were called reference sites. Habitat variables that were not affected by site disturbance were measured at each site (called natural gradient variables) along with collections of invertebrates using kick net methods. Additional sites were sampled for testing and were called test sites. Variables that may be influenced by anthropogenic disturbance were also measured and were called stressor gradient variables. A standardized method including quality assurance and quality control for enumeration of the invertebrates was followed. A total of 256 complete observations were compiled from all years of sampling. Of this total, 86 observations were from reference sites and 170 were from test sites. |
