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David Moser Montana Fish, Wildlife & Parks

David Moser Montana Fish, Wildlife & Parks. The Use Of Barriers to Protect Westslope Cutthroat Trout Populations from Genetic Introgression and Competition by Nonnative Salmonids. Tarbela Dam – Pakistan Third Largest Dam in World 143 Meters. Nerek Dam – Turkmenistan Tallest Dam in World

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David Moser Montana Fish, Wildlife & Parks

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  1. David Moser Montana Fish, Wildlife & Parks The Use Of Barriers to Protect Westslope Cutthroat Trout Populations from Genetic Introgression and Competition by Nonnative Salmonids

  2. Tarbela Dam – Pakistan Third Largest Dam in World 143 Meters Nerek Dam – Turkmenistan Tallest Dam in World 300 Meters

  3. Status Assessment 2002 and 2009 Multistate, massive effort, many bio’s • Historical & Current Distribution • Population Health • (#s mature, habitat quality, non native presence, habitat network • Barriers • Disease Risks • Hybridization

  4. Historical Range 58,030 Miles Current Range 33,500 12,741 Miles in Montana

  5. 5,934 Miles Genetically Unaltered and Suspected Unaltered1,410 Miles No Risk Hybridization

  6. WCT Classification MT • Types of Conservation Populations

  7. Montana Conservation Agreement • Signed agreement and MOU; 2000 and 2007 • Supported by many different groups • 6 NGO’s • 5 Fed • 1 Tribe • Montana Farm Bureau and Montana Stockgrowers Association

  8. Goals of Conservation Agreement Yellowstone & WCT 2007 • Maintain number and miles of conservation populations (pure as well) at 1999 levels • Work on 40 conservation projects a year for WCT • Reduce genetic and demographic risks through conservation projects

  9. Cottonwood Creek (Beartooth WMA) Cottonwood Creek (Highwood Mountains) Barriers vs. Connectivity or Continuum? Fausch et al. 2009, Peterson et al. 2008

  10. Consequences of BarriersLarge and Small Populations • May protect genetic purity, but if too small puts that local population at higher risk of extinction • To hedge against local extinctions need to replicate as many isolated, local populations as possible; human dispersal agents • Barriers protecting larger metapopulations are rare and inherently more prone to failure (e.g. human movement or high flows)

  11. Missouri River Drainage: Reality • The majority of unprotected conservation populations threatened by hybridization and competition • Genetically pure WCT are nearly always protected by some form of barrier and have persisted for > 80 years • In many cases initial genetic samples are pure - further sampling reveals introgression if no barrier present

  12. Usually can’t build unless channel is incised and high gradient • Higher public access more chance of (un)intentional sabotage • Cost/benefit • Every situation is very different…. Constraints on Barriers

  13. Human Dispersal and Maintenance Minimum for Long Term Survival, Sensu Hilderbrand and Kershner 2000 Risks of introgression and re-invasion of non-natives increases with drainage size

  14. Opportunities Increase Multiple Landowners Road Networks High Public Access Marginal Barrier Site Recreational Opportunities (Tenderfoot Creek) High Public Access Good Barrier Site (North Fork Highwood Creek) Barrier Failure Over Time Probability Sabotage Over Time Some Public Access Good to Excellent Barrier Site (Tyrell Creek) Private Landowner Little Public Access Excellent Barrier Site (Smith Creek) Private Landowner Controlled Access Excellent Barrier Site (Cherry Creek) Drainage Size Miles

  15. Strategies Summarized • Isolation • Reduced risk due to introgression, disease, competition/predation • Increased risk due to demographic and stochastic processes; human dispersal and maintenance • Many opportunities for these projects, Not really recreational, except for dentists!

  16. Strategies Summarized, Cont. • Full Connectivity • Reduced risk due to demographic and stochastic processes • Can conserve life-history variation • Increased risk for introgression, disease, competition/predation – increases with drainage size/access • Opportunities for recreational WCT fisheries and harvest

  17. Strategies Summarized, Cont. • Continuum? • Many different lengths of projects • Large enough but with a barrier to benefit from both strategies…5 to 15 miles? • Irrigation reservoirs on private lands? Recreational Opportunities?

  18. Costs Missouri Drainage • Barriers typically cost $100,000 + • Even small projects tend to be costly if designed for the long term • Culvert barriers cost $30,000 to $80,000 + • ≈ 46 Potential projects-just pure WCT • $2,000,000 to $5,000,000

  19. Restoration Projects Missouri River DrainageBarriers and/or Transfers Smith Creek (Highwood Mountains) Whites Creek (Big Belt Mountains)

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