In an earlier post, “Fishing in the Extremes,” I discussed how climate change is impacting fishing conditions in the West. To continue this conversation, this post will review climate change impacts on river ecosystems, outline Trout Unlimited’s conservation strategy, and provide a local example of how TU is responding to the threat by making rivers more resilient to low flows, higher temperatures, and other adverse effects.
Beyond Seasons’ End, a joint publication from TU, Ducks Unlimited, Pheasants Forever, and other wildlife conservation organizations, outlines four primary affects of climate change on coldwater fisheries. These include:
- Causing increased water temperature.
- In turn, this decreases habitat availability, alters migration and spawning patterns, limits food availability, and spreads pests, parasites, and disease.
- Altering stream flows due to increase rain (vs. snow) precipitation, reduced snow accumulation, and earlier snowmelt.
- An early and rapid runoff in the spring, combined with low flows during the summer and fall, stress fish and decrease food supplies.
- Exacerbating natural disturbances, such as wildfires and drought.
- Promoting non-native and invasive species that are more resilient than native species to changing conditions.
To combat these effects, TU has a four-pronged approach to protect, reconnect, restore, and sustain watersheds. TU specifically focuses on the small tributaries that are especially vulnerable to climate change and vital to fish spawning.
Protecting remaining critical habitat areas is key to maintaining healthy downstream flows. This includes not only the rivers and streams habitats, but also the surrounding vegetation that contribute to a vital river ecosystem. Additionally, maintaining the genetic diversity of native fish populations enable populations to better adapt to future environmental change.
Reconnecting high quality habitats is also of key importance as roads, agriculture, and land use changes contribute to increased fragmentation of river systems. Dams, culverts, and other obstacles impede fish from accessing the wide variety of habitats necessary for a healthy population. To this end, TU focuses on the removal or modification of physical barriers and aims to return flows to streams that periodically run dry due to diversions.
Restoring entire watersheds to a healthy, natural state allows fish to better withstand the impacts of rising temperatures, floods, fires, and droughts. This includes habitat restoration, and restoration of native fish populations. By restoring streams that run dry or no longer support native populations, TU is giving fish more room to live and reducing competition against invasive species.
Finally, sustaining conservation and recovery efforts will ensure continued progress towards healthy fish habitats. Engaging local communities and stakeholders in conservation education and action is critical to integrative approach to sustaining healthy fish habitats and populations. Local stakeholders are also vital to the ongoing watershed monitoring and evaluation necessary for adaptive management. Despite all the scientific study of climate change, it remains a somewhat unpredictable threat. Through appropriate monitoring and evaluation of impacts, TU and fish and wildlife management agencies are better positioned for successful adaptation tactics.
Grassroots Defense Tactics
In Colorado, Trout Unlimited has a team of conservationists and scientists working hard to mitigate and adapt to these threats. The Colorado Water Project was formed in 1998 to apply TU’s four conservation principles to the many Colorado rivers and streams that are threatened. In its nearly fifteen years, the CWP has sustained healthy coldwater fisheries by fighting harmful diversion and storage projects, advocating for instream flow legislation, facilitating dialogue among key stakeholders, and enlisting TU volunteers to physically restore vulnerable rivers and streams.
A great example is the work TU is doing for tributaries in the Yampa River system. Three factors make certain tributaries and the suite of native fishes therein especially susceptible to the effects of climate change. First, segments of some tributaries are characterized by overly wide and shallow channels, making them unstable and more susceptible to altering flows. Second, summer temperatures are already nearing the tolerable threshold for species such as the Colorado River Cutthroat Trout. More importantly, the species threatened by these temperatures are often already restricted to the coldest reaches of the streams. Finally, the native fish populations in many tributaries are relatively small, and are isolated from other fish populations.
According to an interview with Brian Hodge, the CWP Project Coordinator for the Yampa/White River Basin, TU would like to address these threats with a strong climate adaptation strategy. Specifically, the strategy would entail the following activities:
- Design, and attain the permits for, restoration work in which we will improve channel function and stability, reduce incoming solar radiation, and increase availability of localized patches of colder water;
- Supervise construction of that restoration work;
- Monitor physical and biological indices (e.g., fish density, stream temperature) to evaluate project success; and
- Work through internal and external channels to disseminate the results of the project and replicate its successes.
Mr. Hodge expects these activities will provide measurable benefits to the tributaries at risk. Installation of log vanes will divert water away from eroding shorelines while concentrating currents and creating pool habitat. Pool excavation will provide spots of deeper, colder water to give fish refuge from warm temperatures. Finally, planting willows and cottonwoods will improve the stability of banks while offering fish protection from the sun.
As climate change continues to negatively impact fish and wildlife in around the world, it is nice to know that groups like TU are working diligently on local levels to offset the effects and keep our rivers and streams healthy and full of fish. The next post will take a look at what Congress is (or isn’t) doing to support anglers through the Sportsmen’s Heritage Act of 2012.