Program in Modeling and Decision Support
Capability/Technical Service - Development of decision support tools
Natural resource managers often face tradeoffs between competing objectives and/or considerable uncertainty in the potential outcome of a given decision. Decision support tools, though no substitute for professional expertise and experience, can help provide consistency and transparency when making difficult choices or evaluating complex problems. Such models can be very useful for repetitive decisions, and are capable of integrating different types of data. Many such tools are probabilistic, so uncertainties in both assumptions and outcomes can be explicitly depicted. This not only informs management but also highlights where additional research is needed.
1) Decision support tools to support native fish management: tradeoffs between threats of nonnative invasions and isolation
Habitat fragmentation and invasion of nonnative fishes are primary contributors to the decline of native salmonids in the western US, but attempts to ameliorate their different effects may elicit different and often conflicting management approaches. Removal of migration barriers to connect native populations to larger stream networks could allow upstream invasions of nonnative fishes, while installing migration barriers to preclude these invasions may exacerbate effects of habitat fragmentation and population isolation. Both actions could threaten native species and integrity of aquatic systems, but fish biologists may employ both barrier installation and barrier removal strategies across the western US without evaluation of the opposing threats. The potential conflicts highlight a challenge in native fish conservation.
Our goal was to formalize an evaluation of tradeoffs between intentional isolation, invasion and conservation of native salmonids. We focused on persistence of native westslope cutthroat trout (Oncorhynchus clarkii lewisi), potential invasion and subsequent effects of nonnative brook trout (Salvelinus fontinalis), and the primary environmental and anthropogenic factors influencing both species and their interactions. Our objectives were to develop and explore the application of a Bayesian Belief Network (BBN) as a decision support tool and highlight results that provide general guidance for biologists and managers. We focused this work on cutthroat trout and brook trout because they represent a widespread and-well defined problem in central and northern Rocky Mountain streams (Fausch et al. 2006), but we believe our approach can be readily adapted to other species.
Partners: US Forest Service, Rocky Mountain Research Station; Colorado State University; US Geological Survey, FRESC; US Forest Service, Region 1
Publication: Peterson, D.P., B.E. Rieman, J.B. Dunham, K.D. Fausch, and M.K. Young. 2008. Analysis of trade-offs between threats of invasion by nonnative brook trout (Salvelinus fontinalis) and intentional isolation for native westslope cutthroat trout (Oncorhynchus clarkii lewisi). Canadian Journal of Fisheries and Aquatic Sciences 65:557-573.
The Model: InVAD 1.1 - BBN decision support model. Please call or e-mail Doug Peterson (360-425-6072 x302 or Doug_Peterson@fws.gov)
Fausch, K.D., Rieman, B.E., Young, M., Dunham, J.B., 2006. Strategies for conserving native salmonid populations at risk from nonnative fish invasions - tradeoffs in using barriers to upstream movement. USDA Forest Service, Rocky Mountain Research Station RMRS-GTR-174.
Fausch, K.D., B.E. Rieman, J.B. Dunham, M.K. Young, and D.P. Peterson. 2009. The invasion versus isolation dilemma: tradeoffs in managing native salmonids with barriers to upstream movement. Conservation Biology 23(4): 859–870.
Peterson, D.P., B.E. Rieman, J.B. Dunham, K.D. Fausch, and M.K. Young. 2007. Analyzing Tradeoffs Between the Threat of Invasion by Brook Trout and Effects of Intentional Isolation for Native Westslope Cutthroat Trout Pages 51-57 in R. F. Carline and C. LoSapio, editors. Wild Trout IX: Sustaining wild trout in a changing world. Wild Trout Symposium, Bozeman, Montana.
2) Decisions support tools to model climate change in aquatic systems.
High-resolution climate datasets based on regional climate models are becoming more widely available, and many researchers are developing suites of models (hydrologic, thermal, geomorphic) to downscale climate effects to aquatic habitats. Decision support tools, such as Bayesian belief networks (BBNs) can integrate and project future changes, provide risk assessments, and prioritize management options. We are currently working with various partners develop models for at risk fish species in the western US, including bull trout (Salvelinus confluentus) and subspecies of cutthroat trout. We anticipate these models to be used by resource managers dealing with aquatic systems, including the USGS, FWS, USFS, BLM, state management agencies, and private organizations that are working to conserve and protect at risk fishes. In addition, we will deliver workshops to managers and provide hands‐on training.
Partners: Colorado State University; US Forest Service, Rocky Mountain Research Station; US Geological Survey; Trout Unlimited.