Implications of Climate Change for Coldwater Habitat and Brook Trout in Pennsylvania

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1 Implications of Climate Change for Coldwater Habitat and Brook Trout in Pennsylvania Jefferson Tyrell Deweber Pennsylvania Cooperative Fish/Wildlife Research Unit Pennsylvania State University Tyler Wagner USGS Fish and Wildlife Cooperative Unit Pennsylvania State University

2 Brook Trout Ecologically important and sensitive species Culturally important the state fish of PA Only native salmonid and important gamefish Special protection for streams in PA with: High quality & coldwater designation Class A brook trout stream Biomass > 30kg per ha Natural reproduction Wilderness trout stream Photo by Tyler Wagner

3 Current Status of Brook Trout What about 80 years from now? From Hudy et al Will future changes cause declines?

4 Study Objective Climate change Land Use Change Air Temperature Landscape Water Temperature

5 Temperature Modeling We predicted daily water temperature Using a neural network ensemble Accuracy: ~1.9 C Predictors: Air temperature Watershed area Watershed mean aspect Watershed forest cover Local riparian forest cover DeWeber and Wagner (In Review)

6 Predicted Temperature 1997 baseline temp. predictions 5 year average daily temperature, centered on 1997 Mean July temp. Important for brook trout Other metrics possible e.g., Max weekly temp.

7 Predicted Water Temperature Penns Creek Watershed

8 Study Objective Climate change Land Use Change Air Temperature Landscape Water Temperature

9 Brook Trout Modeling We predicted probability of brook trout occurrence Using hierarchical logistic regression with Bayesian estimation Included predictors: Modeled mean July water temperature Soil permeability Agricultural land cover Developed land cover

10 Brook Trout Model Output

11 Brook Trout Model - PA What about presence/ absence? Depends upon objective Identify potential habitat? Identify highest quality habitat? Maximize overall classification accuracy? Cutoff = 0.46

12 Brook Trout Model Output Penns Creek Watershed

13 Study Objective Climate change Land Use Change Air Temperature Landscape Water Temperature

14 Climate Change Effects Mean July water temperature changes Genmom - Low Echam - High

15 Climate Change Effects Mean July water temperature changes Genmom (Low) Echam (High)

16 Climate Change Effects Brook trout distribution changes Genmom - Low Echam - High -31.7% -59.0%

17 Climate Change Effects Brook trout distribution changes Genmom (Low) -56.4% Echam (High) -66.1%

18 Climate Change Effects Penns Creek watershed -14.3% Genmom (Low) -51.3% Echam (High)

19 Summary of Climate Change Effects Driven by predicted water temp. increases Throughout eastern native range: Between 31.7% and 59% projected lost Throughout Pennsylvania: Between 56.4% and 66.1% projected lost In Penns Creek watershed Between 14.3% and 51.3% projected lost Also have information on uncertainty

20 Discussion Implications for Brook Trout conservation and fishing opportunities Increasing fragmentation of populations Lost revenue from minimal investment fishery

21 Discussion Assumptions: No adaptation and no refugia How can we use these scenarios? Can prioritize restoration and conservation activities in PA Maintain flexibility See my poster: Role of riparian forests in mitigating changes

22 Implications for Pennyslvania Could affect how many streams are protected Currently protected as class A or cold water What if populations are reduced or extirpated? Implications for local and downstream water quality Are there options to extend protection?

23 Conclusions Temperature model Covers large region with reasonable accuracy Linked to individual stream reaches Useful for more than Brook Trout Rainbow mussel Sliimy sculpin

24 Conclusions Climate change acts broadly: Models suggest losses of up to 59% of thermally suitable habitat in the range Up to 66% in PA could be lost Implications for river protection in PA Scenarios can help keep us flexible Photos from PA Fish and Boat website

25 Acknowledgements Fish habitat, climate and land use change project partners State agencies and researchers for providing water temperature and fish sampling data (too many to list here) Steve Midway for helping acquire fish sampling data USGS National Climate Change and Wildlife Science Center for project funding References: Hudy, M., Thieling, T.M., Gillespie, N., Smith, E.P., Distribution, status, and land use characteristics of subwatersheds within the native range of brook trout in the Eastern United States. N. Am. J. Fish. Manage., 28(4): DeWeber, J.T. and T. Wagner. In Review. A regional neural network ensemble for predicting daily river water temperatures. Journal of Hydrology

26 Questions? Photo from PA Boat and Fish website