A small puddle where there were several Bull Trout stranded below a severely hanging culvert. This picture also shows how erosion and sedimentation from the road can impact streams at crossing locations as well.
Habitat Fragmentation. What is it? Why is it important?
The ability for fish to move between habitats is important to the health of their population. For example, some fish will move throughout their watershed to find cooler or warmer water, a term referred to by biologists and other professionals as thermal refugia. These habitats may be fed by groundwater, have more complex habitat with deep pools and undercut banks, or have abundant streamside vegetation which helps to cool the water. If fish are unable to move between different habitats, populations can lose their ability to respond to changes over a season, a year, or across generations. This is the case with many of Alberta’s native fish species. Many aquatic habitats across Alberta have been intersected and fragmented by dams, and by thousands of stream crossings associated with the vast network of roads and other linear features. These barriers do not allow for upstream fish passage due to improper installation or deterioration over time.
Fragmentation refers to the inability for fish to access different parts of their habitat which they may need for various parts of their lifecycle or to respond to rapid changes in environmental conditions. In order to address habitat fragmentation, TUC launched the Reconnecting Canada Campaign to address this problem across the country.
This past summer, Trout Unlimited Canada staff spent two days in the Upper Red Deer River watershed working with Fisheries Management Staff from Alberta Environment and Parks, to conduct backpack electrofishing in a handful of streams where there may be upcoming opportunities to address fish passage concerns as part of the North Central Native Trout Recovery Program.
Over the course of two days, several sites were visited on Logan Creek, McCue Creek, and Bull Creek; all tributaries of the Red Deer River, and all containing Bull Trout. Like many streams in the region, all three creeks have numerous issues impacting native fish populations, including fragmentation by problem culverts.
A McCue Creek Bull Trout rescued from the puddle where it was stranded, and returned to the Red Deer River downstream.
During the field tour, TUC and AEP staff identified a group of bull trout (a provincially threatened species) stranded below a severely perched culvert on McCue Creek. These fish were likely moving upstream searching for cooler water as water temperatures increased; when stream flows became too low, they were trapped in the plunge pool below the culvert. In this case, fish couldn’t pass upstream due to the perched culvert, and they couldn’t move downstream because of low flow. A fish rescue was performed and several Bull Trout were relocated to the Red Deer River downstream. This crossing provides a great example of how problematic just one small crossing can be for fish trying to move between habitats. Consider the hundreds of thousands of problem crossings across Canada, and you can see how this issue is a major challenge for conserving freshwater ecosystems and the species they support.
TUC will continue to work together with our partners in government, industry, and the public to tackle the issue of fragmentation here along the Eastern Slopes, and in watersheds across Canada. TUC has already completed several reconnection projects in Alberta and Ontario, with more scheduled for completion in 2018. To learn more about the Reconnecting Canada campaign, please visit the program webpage.
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