My MSc research at the University of Alberta took on a duel perspective: both ecological and managerial. I first focused on gaining a better understanding of the extent to which stream crossing structures, such as culverts and bridges, are influencing stream fishes in the boreal forest, and second on determining methods for prioritizing the restoration of poorly functioning culverts that are fragmenting fish habitat.
Industrial activities in Alberta’s boreal forests have created large networks of roads and in turn the construction of thousands of stream-crossing structures. Due to the highly dynamic and stressful environment in which boreal fishes live, they are extremely sensitive to additional anthropogenic stressors. Watersheds in west-central Alberta are an ideal example of this, particularly as they contain valuable habitat for two species of special concern: Bull Trout and Arctic Grayling. Accordingly, two question guided my research program: 1) are stream crossings a primary driver of fish communities in the boreal forest?, and 2) how can be most efficiently restore lost or degraded habitat for native freshwater fishes?
To address these questions, I turned to a watershed experiencing growing industrial development in west-central Alberta where I examined instream habitat and fish communities in 33 streams that were crossed by either 1) culverts, 2) bridges, or 3) lacked a crossing structure (reference streams). I found that culverted streams were characterized by high percentages of fine-grained, silty substrates, reduced water velocity, higher water temperatures, decreased dissolved oxygen concentration, and increased water depth. Overall fish density and richness were impacted by stream crossings indicating fish habitat fragmentation. Species-specific responses were observed, with those adapted to slower moving, deeper and more sediment-laden streams more prevalent on culverted streams. My results suggest that alterations to fluvial ecosystems associated with stream crossings, both in terms of habitat fragmentation and degradation, may be driving large-scale changes in stream fish communities in the boreal forest.
The second phase of my research project explored restoration potential for this same watershed. As the repair or removal of problem culverts is an expensive endeavor, watershed-based prioritization methods are essential for the efficient allocation of restoration dollars. Thus, I assessed the applicability of recently developed stream crossing mitigation prioritization models (i.e. budget optimization) that maximizes habitat availability for stream resident fish within a stream network. Results from these analyses indicate that a large proportion of potential connectivity gain can be realized in this watershed with a moderately low investment (~$200K to $500K). Further, it is clear that by incorporating species-specific habitat suitability and dispersal information into optimization analyses, ecologically-meaningful restoration outcomes are much more likely to be achieved.
Broadly, my results suggest problems for many species of fish found in the western boreal region, particularly species of concern such as arctic grayling and bull trout. It is my hope that these results will help influence management decisions throughout the boreal region, as well as elsewhere in the world.
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I am currently a MSc. student in the Fish Ecology and Conservation Physiology Lab (www.fecpl.ca) with Dr. Steve Cooke at Carleton University, and Dr. Mike Power at the University of Waterloo. My research focuses on the spatial and trophic ecology of salmonids in reservoirs of the Peace River, BC. More specifically, I am interested in the habitat selection and behavioural interactions of predatory bull trout (Salvelinus confluentus) and a key prey species, kokanee (Oncorhychus nerka). Supported by a Collaborative Research and Development Grant in partnership with BC Hydro and NSERC, we have deployed an acoustic telemetry array in the Peace Reach of Williston Lake, as well as Dinosaur Lake, two reservoirs near the headwaters of the Peace River in northern BC.
My work forms part of a larger research initiative that is targeted at addressing the effects of hydro dam operation on fish physiology and behaviour. A key concern for future hydroelectric development is the potential for elevated total dissolved gas concentrations downstream of dams to alter habitat use by fish. Another important consideration is the risk of fish encountering intakes, and becoming entrained. By tracking the vertical and lateral movements of bull trout and kokanee year-round, we are developing a greater understanding of the factors that affect habitat use and movement behavior in these culturally important species. Using a multi-species approach also allows us to investigate the predator-prey dynamics of this human altered landscape, and uncover the underlying drivers of habitat use. With more trips planned and more fish to be tagged, stay tuned for exciting developments on our research!