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Using GIS and Multivariate Statistical Analysis to Assess the Relations between Aquatic Habitat Indicators and Forest Harvesting at Both Stream Reach and Watershed Scales
Wei, Adam
Using appropriate indicators is an important approach to support sustainable forest and watershed management and has been widely recognized in the scientific and resource management communities. This approach is particularly relevant in BC because of the recent introduction of the results-based Forest and Range Practices Act (FRPA). In spite of significant efforts devoted to selection of forest sustainability indicators, many identified watershed indicators have not been well tested and applied in supporting design of forest management strategies for protection of both terrestrial and aquatic values in BC. Lack of well-tested, sensitive, measurable indicators as well as a system for their broad application will greatly constrain our ability to evaluate the environmental implications of the results-based FRPA. In addition, the Department of Fisheries and Oceans recently released The Wild Salmon Policy in June 2005. The goal of this policy is to restore and maintain healthy and diverse salmon populations and their habitats for the benefit and enjoyment of Canadians, in perpetuity. Since most of BC?s watersheds provide critical habitat for salmon and given the close linkage between land and water systems, it has been commonly accepted that the most effective approach for protection of salmon habitat is through sustainable forest or land management. However, implementing such an approach requires a deeper understanding of the relationship between aquatic habitat indicators and forest harvesting. Thus, there is clearly a need to conduct scientific research to assess the relationship between aquatic habitat indicators and forest management to support implementation of FRPA and the Wild Salmon Policy. There are many watershed indicators that include hydrology, water quality, biology and channel morphology. After reviewing and comparing the above-mentioned indicators, MacDonald (1994) suggested that those stream morphology-related aquatic habitat indicators (i.e. in-stream wood, pools, substrates, embedment etc.) are likely more sensitive to forest management and land use changes, and they can also be easily measured and monitored. However, many studies have demonstrated that aquatic habitats are influenced by factors operating at multiple spatial scales (Allen and Johnson 1997; Johnson and Covich 1997; Richards et al., 1997; Stein et al., 2001; Schreier and Brown 2001; Benda 1999). At the watershed scale, geomorphology and climate affect stream hydrology, sedimentation, nutrient input and channel morphology. At more local scales, land use, through alternation of riparian vegetation and stream conditions, can have significant influences on in-stream wood recruitment and its associated habitat attributes (Wei 2003; Chen et al. 2005) as well as macroinvertebrate assemblages (Richards and Host 1994). Thus, stream habitat indicators must be assessed at both reach and watershed scales. A big challenge in watershed management is separating the impacts of forest disturbance at both the reach and watershed scales. Johnson and Gage (1997) provided a useful review on various research methods for understanding landscape or watershed influence upon aquatic ecosystems. These methods include spatial statistics, multivariate statistics, structural equation modeling and fuzzy logic. Among those methods, multivariate statistics combining with GIS spatial analysis has been extensively used, and was approved to be a robust approach (Allen et al., 1997; Richards et al. 1996; Stewart et al., 2001). In this research, we propose to use GIS and multivariate statistical analysis to assess the relations between aquatic habitat indicators and forest harvesting at both stream reach and watershed scales in the BC interior. GIS is a powerful tool for development and analysis of spatial data, enabling researchers to address multi-scale issues much more effectively (Wei and Davidson 1999; Allen and Johnson 1997). However, the utility of GIS is largely dependant ...
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Executive Summary
Aquatic Habitat Indicators (Poster)

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