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United States Department of Agriculture

Agricultural Research Service

Title: Large woody debris and salmonid habitat in the Anchor River basin, Alaska, following an extensive spruce beetle (Dendroctonus rufipennis) outbreak

Authors
item Rinella, Daniel - U OF ALASKA, ANCHORAGE
item Booz, Michael - U OF ALASKA, ANCHORAGE
item Bogan, Daniel - U OF ALASKA, ANCHORAGE
item Boggs, Keith - U OF ALASKA, ANCHORAGE
item Sturdy, Michelle - U OF ALASKA, ANCHORAGE
item Rinella, Matthew

Submitted to: Northwest Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 15, 2008
Publication Date: February 1, 2009
Repository URL: http://hdl.handle.net/10113/33736
Citation: Rinella, D.J., Booz, M., Bogan, D., Boggs, K., Sturdy, M., Rinella, M.J. 2009. Large woody debris and salmonid habitat in the Anchor River basin, Alaska, following an extensive spruce beetle (Dendroctonus rufipennis) outbreak. Northwest Science 2009 83(1):57-69.

Interpretive Summary: A widespread and intense spruce beetle outbreak has killed most of the mature white spruce trees across many watersheds in south-central Alaska. To investigate the potential habitat impacts in a salmon stream, we characterized the current abundance and species composition of large woody debris (LWD), examined the linkages between LWD and salmon habitat, and estimated changes in LWD abundance and associated pool habitat over time. We project the spruce beetle outbreak to result in a substantial net increase in LWD abundance and pool habitat over a 50-year span.

Technical Abstract: A widespread and intense spruce beetle outbreak has killed most of the mature white spruce trees across many watersheds in south-central Alaska. To investigate the potential habitat impacts in a salmon stream, we characterized the current abundance and species composition of large woody debris (LWD), examined the linkages between LWD and salmonid habitat, and estimated changes in LWD abundance and associated pool habitat over time. LWD abundance was relatively low (97 pieces/km overall) and varied widely according to riparian vegetation typology, ranging from 15 pieces/km at sites with non-forested riparian zones to 170 pieces/km at sites adjacent to cottonwood forest. LWD provided significant fish cover in pools, especially in cottonwood forest stream reaches. LWD-formed pools were relatively rare (15% of total), but LWD abundance explained much of the variation in pool frequency (r2 = 0.86 in spruce forest reaches) and in the proportion of pool habitats (r2 = 0.85 in cottonwood forest reaches). We project the spruce beetle outbreak to result in a substantial net increase in LWD abundance and pool habitat over a 50-year span.

Last Modified: 8/27/2014
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