Predicting climate change effects on aquatic ecosystems in the Crown of the Continent

Science Center Objects

Climate change poses a serious threat to natural resources, biodiversity, and ecosystem services in the United States, especially in the Rocky Mountain Ecoregion. The Crown of the Continent Ecosystem (CCE) is considered one of the largest, most pristine, and biodiverse ecosystems in North America, spanning the northern Rocky Mountains of the United States and Canada. In the heart of the CCE is the Transboundary Flathead Watershed, a significant portion of which forms Waterton-Glacier International Peace Park, a World Heritage Site and Biosphere Reserve (Fig. 1). The Transboundary Flathead originates in British Columbia and flows into Montana and is considered one of America's most biodiverse river systems. Its water quality is pristine, it harbors abundant and diverse aquatic life, and it has long been recognized as a range-wide stronghold for two hallmark threatened fish species, the bull trout and the westslope cutthroat trout.

Satellite image of the Crown of the Continent region.

Satellite image of the Crown of the Continent region.Public domain

UNESCO (2010) recently concluded: “The Flathead is regarded as one of the last of America’s remaining wild rivers and of global ecological significance…and recognizing the clear evidence for ecological and environmental stress under changing climatic regimes, specific programs of management and associated monitoring and research should be developed to combat climate change impacts. Adaptive management strategies should give emphasis to enhancing the resilience and capacity of wildlife and plants in adjusting to changing environmental conditions”.

The CCE is experiencing warmer winters, reduced snowpack, increased fires, increased stream temperatures, and more variable hydrologic regimes (Pederson et al. 2010). These climate-induced environmental changes are likely to result in significant changes in the distribution, abundance, phenology, and genetic diversity of many aquatic species, particularly inland salmonids and rare invertebrates. Moreover, climate change is expected to exacerbate existing stressors of habitat loss and invasive species. Therefore, understanding the potential impacts of climate change and interactions with ongoing human stressors on aquatic ecosystems is important for developing and implementing pro-active conservation, recovery, and management programs at regional and watershed scales in the Rocky Mountain Region.

This continued research project builds on an existing climate change and transboundary research program evaluating physical (thermal, hydrologic, geomorphic) and biotic (invasive species) effects on foodwebs (rare macroinvertebrates), native salmonids (threatened bull trout and westslope cutthroat trout), and aquatic habitats in the Transboundary Flathead River system and CCE. The project is integrating downscaled and regionalized climate models (e.g., stream temperature) with riverscape data, fine-scale aquatic species vulnerability assessments, population genetic connectivity, and remotely sensed riparian and aquatic habitat connectivity analyses. Results will be used to: identify populations and habitats most susceptible to climate change and other cumulative stressors (e.g., habitat loss and invasive species); develop an Aquatics Adaptation Plan for the Transboundary Flathead; and complete conservation population assessments for native bull and cutthroat trout across the CCE to help managers consistently prioritize conservation delivery options in response to or in anticipation of climate change and other stressors.

 

Funding: Great Northern Landscape Conservation Cooperative (http://greatnorthernlcc.org/supported-science/35), National Science Foundation, Northwest Climate Science Center, USGS

 

Agency Partners:  Crown Managers Partnership (USA and Canada), U.S. Geological Survey, The University of Montana, Flathead Basin Commission, Glacier National Park, U.S. Forest Service, U.S. Fish & Wildlife Service, Montana Fish, Wildlife & Parks, Confederated Salish and Kootenai Tribes, Montana State University, BC Ministry of Forests, Lands, and Natural Resources, Alberta Ministry of Environment and Sustainable Resource Development, The Wilderness Society, Crown of the Continent Conservation Initiative, Crown Roundtable, Southwestern Crown Collaborative Forest Landscape Restoration Project, Great Northern Landscape Conservation Cooperative, and Northern Rockies Adaptation Partnership.