Relationship between Large Woody Debris Characteristics and Pool Formation in Small Coastal British Columbia Streams

Abstract The characteristics and function of large woody debris (LWD) were measured in 41 small (1.2-11.2-m bank-full channel width), fish-bearing streams in coastal British Columbia to determine how total LWD abundance and the features of individual LWD pieces (diameter, length, orientation, and presence of a rootwad) influenced the effectiveness of pool formation. Pool spacing (the number of channel widths between channel-spanning pools) was a decreasing power function of total LWD abundance, but the relationship was relatively weak. Stratification of sites by channel gradient improved the model fit, steeper streams (≥2% gradient) having a significantly lower pool spacing than lower-gradient streams (<2%). The proportion of LWD that formed pools increased from 6% for pieces with a diameter of 15-30 cm to 43% for pieces with a diameter of more than 60 cm. Large woody debris more than 60 cm in diameter formed a higher proportion of pools across all channel widths. A simple, size-structured model of LWD ab...

[1]  M. Gordon Wolman,et al.  Fluvial Processes in Geomorphology , 1965 .

[2]  D. Montgomery,et al.  LARGE WOODY DEBRIS JAMS, CHANNEL HYDRAULICS AND HABITAT FORMATION IN LARGE RIVERS , 1996 .

[3]  S. Johnson,et al.  Seasonal Changes in Habitat Use by Juvenile Coho Salmon (Oncorhynchus kisutch) in Oregon Coastal Streams , 1992 .

[4]  Kumiko Hosaka.  In the forest , 1996, SIGGRAPH '96.

[5]  R. Naiman,et al.  Stream Channel Morphology and Woody Debris in Logged and Unlogged Basins of Western Washington , 1994 .

[6]  Gordon E. Grant,et al.  When do logs move in rivers? , 2000 .

[7]  Robert E. Bilby,et al.  Changes in Characteristics and Function of Woody Debris with Increasing Size of Streams in Western Washington , 1989 .

[8]  J. Gore,et al.  Hydraulic Stream Ecology: Observed Patterns and Potential Applications , 1988, Journal of the North American Benthological Society.

[9]  D. Knighton.  Fluvial forms and processes , 1984 .

[10]  A. Richmond,et al.  Characteristics and function of large woody debris in subalpine Rocky Mountain streams in northern Colorado , 1995 .

[11]  G. Pess,et al.  Modeling Recovery Rates and Pathways for Woody Debris Recruitment in Northwestern Washington Streams , 2000 .

[12]  Eric A. Parkinson,et al.  Habitat factors affecting the abundance and distribution of juvenile cutthroat trout (Oncorhynchus clarki) and coho salmon (Oncorhynchus kisutch) , 2000 .

[13]  P. Bisson,et al.  Function and Distribution of Large Woody Debris , 1998 .

[14]  J. Rosenfeld,et al.  Fitness consequences of habitat use for juvenile cutthroat trout: energetic costs and benefits in pools and riffles , 2001 .

[15]  D. Sprugel,et al.  Correcting for Bias in Log‐Transformed Allometric Equations , 1983 .

[16]  T. Quinn,et al.  Experimental evidence for the effect of depth and structure on the distribution, growth, and survival of stream fishes , 1995 .

[17]  B. Tabachnick,et al.  Using Multivariate Statistics , 1983 .

[18]  Kathleen Sullivan,et al.  Riparian aquatic interaction simulator (RAIS): a model of riparian forest dynamics for the generation of large woody debris and shade , 2002 .

[19]  G. Hartman,et al.  Distributions of Juvenile Steelhead and Cutthroat Trout (Salmo gairdneri and S. clarki clarki) Within Streams in Southwestern British Columbia , 1968 .

[20]  Douglas J. Martin.  The Influence of Geomorphic Factors and Geographic Region on Large Woody Debris Loading and Fish Habitat in Alaska Coastal Streams , 2001 .

[21]  J. Sedell,et al.  From the Forest to the Sea: The Ecology of Wood in Streams, Rivers, Estuaries and Oceans , 1994 .

[22]  G. Baskerville.  Use of Logarithmic Regression in the Estimation of Plant Biomass , 1972 .

[23]  D. Montgomery,et al.  Historical changes in the distribution and functions of large wood in Puget Lowland rivers , 2002 .

[24]  Kenneth Gregory,et al.  Coarse woody debris in stream channels in relation to river channel management in woodland areas , 1992 .

[25]  D. Montgomery,et al.  Pool Spacing in Forest Channels , 1995 .

[26]  Timothy J. Beechie,et al.  Relationships between Channel Characteristics, Woody Debris, and Fish Habitat in Northwestern Washington Streams , 1997 .

[27]  T. Lisle.  Stabilization of a gravel channel by large streamside obstructions and bedrock bends , 1986 .

[28]  M. L. Murphy,et al.  Effects of Clear-cut Logging with and without Buffer Strips on juvenile Salmonids in Alaskan Streams , 1986 .

[29]  W. N. Melhorn,et al.  Rhythmic spacing and origin of pools and riffles , 1978 .

[30]  M. L. Murphy,et al.  Input and Depletion of Woody Debris in Alaska Streams and Implications for Streamside Management , 1989 .

[31]  G. Brierley,et al.  Mediated equilibrium: the influence of riparian vegetation and wood on the long‐term evolution and behaviour of a near‐pristine river , 2002 .