Research

My research interests include:

1) Understanding how habitat structure affects biological processes in streams;

2) Longitudinal changes in habitat structure and energy flow along the River Continuum;

3) Modelling fish habitat structure and optimal flows;

4) Developing protocols for determining habitat requirements of fish;

5) Recovery of freshwater fishes;

6) Stream restoration;

7) Bioenergetic modelling to predict growth of drift-feeding fishes.

Stream channels are a great way for testing small-scale ecological issues in running waters.

So are enclosures, although there is no substitute for larges scale manipulations.

Current Research

2007 to 2009 - Assessing critical habitat and threats to endangered Stickleback Species pairs (BC Forest Science Program and Interdepartmental Recovery Fund, $84,000 over 2 years)

            Stickleback species pairs are red-listed and globally unique in that a benthic and limnetic species have evolved in the same lakes.  One species pair (Hadley Lake) has already been extirpated and another has collapsed into a hybrid swarm (Enos Lake). There is an urgent need to identify critical habitat as well as to unambiguously identify threats and the cause of hybridization in Enos Lake. This project is designed to identify critical habitat through a combination of 1) habitat identification and mapping in species pairs lakes, 2) assessment of the habitat attributes that are necessary for species persistence by contrasting the attributes of species pairs lakes relative to single-species stickleback lakes, 3) assessment of fluctuations in habitat availability associated with seasonal and human-induced changes in water levels. A combination of observational studies and experiments will be used to unambiguously determine the potential roles of watershed development, changes in water quality, and introduction of crayfish as causative factors leading to hybridization in Enos Lake.

2006 to 2011 - The effect of habitat structure on trophic level transfer efficiency and adaptive tradeoffs by juvenile salmonids (NSERC Discovery, $81,000 over 5 years)

            Physical habitat structure is a key ecosystem attribute that influences both basal system productivity and the transfer of energy to higher trophic levels in streams. Despite extensive research on juvenile salmon habitat relationships, the mechanisms whereby habitat structure constrains adaptations and production of drift-feeding fish remain poorly understood. This research will involve a series of experiments to evaluate the effects of physical habitat on i) adaptive constraints for drift-feeding fish, ii) transfer efficiency of energy to the fish trophic level along a longitudinal downstream gradient, and iii) bottom-up effects of habitat structure on fish production mediated through increased production of invertebrate prey. Research will be carried out in both natural and artificial stream channels, and will be used to develop and parameterize a general bioenergetic model for predicting the effects of changes in habitat, temperature, flows, and prey abundance on juvenile salmon productive capacity.  

Past Research

2004 to 2005 - Off-channel habitat structure effectiveness assessment and design of a decision-support tool for off-channel habitat structure design (HCTF $40,000)

      Numerous off-channel habitat structures to restore and enhance salmonid populations have been constructed in rivers and streams throughout Canada and the Pacific Northwest.  However, assessment of the effectiveness of different structures and designs (in terms of juvenile salmonid growth, survival, or smolt output) has been limited.  We will i) extract data from the literature to compare smolt production data from channels of contrasting design to make general inferences about how design affects production; and ii) use growth experiments and mark-recapture in focal off-channel habitats of contrasting design to assess the mechanisms whereby design affects performance of individuals.

2004 to 2006 - Implications of static riparian reserve zones for long-term function of naturally migrating river channels (FSP $78,000)

            Riparian reserve zones in British Columbia have fixed widths, beyond which timber harvesting can take place in a management zone.  It is assumed that buffers of this width will, over the long term, contribute natural levels of Large Woody Debris input that maintain channel structure and fish habitat, similar to intact riparian forest.  However, this does not take into account the fact that stream channels are active and stream banks naturally migrate through erosion. Over time bank erosion can lead to a significant narrowing of the portion of the buffer with intact forest available to deliver LWD to the stream channel.  This project will model the effects of migration rate of stream channels in different geomorphic contexts on the long-term adequacy of present fixed-width buffers to maintaining natural LWD loadings to streams. 

2004 to 2006 – Developing indicators of stream ecosystem health and capacity for juvenile salmonids (FSP $84,000)

             The monitoring and assessment of stream condition, function, and carrying capacity for fish requires application or development of appropriate assessment indices and protocols.   Goals of this project are to determine which combinations of physical and biological variables are the best indicators of stream condition (in terms of capacity to support juvenile salmon), with a particular emphasis on the use of invertebrate drift abundance as an index of productive capacity, and to assess the costs and benefits of data acquisition involving varying levels of effort, providing a formal basis for optimizing information gained for effort expended. 

2002 to 2003 - Modelling the effects of turbidity on growth rates of juvenile salmonids (FII  $22,000)

            No models exist for quantitatively estimating the impact of chronic or episodic increases in low level turbidity on juvenile salmonid growth rates.  To provide a credible basis for estimating the impacts of increased turbidity, and to provide a tool for developing monitoring and assessment guidelines for forestry impacts on stream turbidity, we are developing a model for predicting the effects of chronic and episodic low-level turbidity on growth rates of stream-dwelling salmonids. 

2001 to 2003 - Modelling the effects of Large Woody Debris Inputs on juvenile anadromous cutthroat trout and coho abundance (FRBC  $80,000 over 2 years)

            Although the general negative impacts of decreased LWD are well documented, no quantitative tools are available for directly predicting how changes in LWD input rate will affect fish abundance in small streams.  We will develop a model linking riparian management (e.g. buffer width) to LWD input rates, small stream channel structure, and abundance of juvenile anadromous cutthroat trout and coho salmon.  This will be done by linking recent research on juvenile cutthroat trout habitat associations (Rosenfeld and Boss 2001, Rosenfeld et al. 2000, Rosenfeld 2000) to existing (Beechie et al. 2000) and developing LWD recruitment models (Hogan 1995).  The model will then serve as an interactive management tool that can be used to predict long-term impacts of different riparian management scenarios on channel structure and juvenile salmonid abundance.

1996 to 2000 - Quantifying habitat requirements of the freshwater stages of anadromous coastal cutthroat trout with respect to forest harvesting activities   (FRBC 1996-1999 $186,000 over 3 years).

            Juvenile anadromous cutthroat trout rear for up to 3 years in small coastal streams.  It is unclear to what degree current forest practices protect their rearing streams.  Research involves a combination of synoptic surveys of cutthroat density and stream channel/habitat structure in logged and unlogged watersheds, and detailed studies of habitat choice and fitness consequences for cutthroat juveniles, including telemetry of 2 year old parr to identify habitat use during winter floods.   Goals are i) to determine the importance of channels structure and hydraulic refuges associated with LWD to juvenile cutthroat fitness, particularly overwinter survival, ii) to quantitatively understand the relationship between cutthroat density and habitat structure associated with LWD, and iii) to model the impact of different riparian management strategies on LWD input rates, channel structure, and ultimately cutthroat density.