Quantifying the Potential Water Quality Benefits of Agricultural Conservation Practices for Stream Fish Conservation in the Western Lake Erie Basin 29 July 2016

Quantifying the Potential Water Quality Benefits of Agricultural Conservation Practices for Stream Fish Conservation in the Western Lake Erie Basin 29 July 2016 Final Report Western Lake Erie Basin Conservation Effects Assessment Project – Wildlife Submitted to US Department of Agriculture, Natural Resources Conservation Service Submitted by The Nature Conservancy (Cooperative Agreement 68-7482-12-504) and The Ohio State University (Cooperative Agreement 68-7482-13-502) and Project Partners, the USDA-Agricultural Research Service and Ohio Sea Grant i Quantifying the Potential Water Quality Benefits of Agricultural Conservation Practices for Stream Fish Conservation in the Western Lake Erie Basin S. Conor Keitzer1, Stuart A. Ludsin1, Scott P. Sowa2, Anthony M. Sasson3, Gust Annis2, Jeff G. Arnold4, Amy Brennan5, Prasad Daggupati6, August M. Froehlich3, Matthew E. Herbert2, Carrie Vollmer-Sanders7, Michael J. White4, Christopher J. Winslow8, and Haw Yen9 1 Aquatic Ecology Laboratory, Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH 43210, USA 2 The Nature Conservancy, 101 E Grand River Ave., Lansing, MI 48906, USA 3 The Nature Conservancy, 6375 Riverside Dr. Suite 100, Dublin, OH 43017, USA 4 USDA, ARS, Grassland Soil and Water Research Laboratory, Temple, TX 76502, USA 5 The Nature Conservancy, 20937 Parklane Drive, Fairview Park, OH 44126, USA 6 Texas A&M AgriLife Research, Texas A&M University, 221B Spatial Science Laboratory, 1500 Research Plaza, College Station, TX 77943, USA 7 The Nature Conservancy, 330 Intertech Pkwy #110, Angola, IN 46703, USA 8 Ohio Sea Grant, 1314 Kinnear Rd., Columbus, OH 43212, USA 9 Blackland Research and Extension Center, Texas A&M University, 720 East Blackland Rd., Temple, TX 76502, USA Suggested Citation: Keitzer, S.C., S.A. Ludsin, S.P. Sowa, A.M. Sasson, G. Annis, J.G. Arnold, A. Brennan, P. Daggupati, A.M. Froehlich, M.E. Herbert, C. Vollmer-Sanders, M.J. White, C. J. Winslow, and H. Yen. 2016. Quantifying the Potential Water Quality Benefits of Agricultural Conservation Practices for Stream Fish Conservation in the Western Lake Erie Basin. Final Report submitted to NRCS Conservation Effects Assessment Project. 64 pp. Cover Photo: Maumee River at Roche de Boeuf, near Waterville, Ohio ii TABLE OF CONTENTS List of Tables…………………………………………………………………………………. iv List of Figures………………………………………………………………………………… v Executive Summary………………………………………………………………………….. vi Acknowledgements…………………………………………………………………………... ix Introduction…………………………………………………………………………………... 1 Project Plan…………………………………………………………………………………… 4 Study Area……………………………………………………………………………………. 6 Objective 1: Watershed Model Development………………………………………………... 7 Objective 2: Biological Model Development & Baseline Predictions………………………. 11 Objective 3: Quantifying Potential Environmental Benefits………………………………… 27 Recommendations for Improving our Approach…………………………………………….. 53 Conclusions and Implications………………………………………………………………... 55 Literature Cited……………………………………………………………………………….. 57 Appendix A: Daggupati et al. 2015. Hydrological Processes 29:5307-5320 Appendix B: Yen et al. 2016. Science of the Total Environment. http://dx.doi.org/10.1016/j.citotenv.2016.202 Appendix C: Keitzer et al. 2016. Journal of Great Lakes Research. http://dx.doi.org/10.1016/j.jglr.2016.05.012 iii LIST OF TABLES Table 1. SWAT model validation statistics……………………………………………. 8 Table 2. Simulated water quality conditions for Baseline scenario………….………… 10 Table 3. Model selection statistics for fish metrics…………………….………………. 15 Table 4. Parameter estimates and validation statistics for fish metrics………………… 16 Table 5. Non-water quality variables included in species distribution models………... 22 Table 6. Validation statistics for species distribution models………………………….. 23 Table 7. Agricultural conservation practices included in conservation scenarios……... 28 Table 8. Variables used to develop threat index…………...………………………….... 31 Table 9. Environmental benefits of conservation scenarios relative to Grassland scenario……………………………………………………………………….. 41 Table 10. Model selection statics for relationships between reductions in agricultural inputs and improvements in stream metrics…………………………………... 44 Table 11. Coefficient estimates from models describing relationships between reductions in agricultural inputs and improvements in stream fish metrics…... 45 iv LIST OF FIGURES Figure 1. Land-use in the Western Lake Erie Basin …………………………………… 3 Figure 2. Conceptual diagram of Western Lake Erie CEAP-Wildlife project…………. 5 Figure 3. Simulated water quality conditions in subwatersheds ………………………. 9 Figure 4. Locations of fish community data used to develop biological models………. 12 Figure 5. Modeled relationships between fish community metrics and water quality…. 17 Figure 6. Forecasted stream biological conditions based on Baseline simulated water quality………………………………………………………………………… 18 Figure 7. Comparison of stream biological conditions forecasted for the Baseline scenario and Grassland scenario……………………………………………... 19 Figure 8. Relative influence of different factors on sensitive species distributions….... 24 Figure 9. Forecasted sensitive species richness in subwatersheds based on Baseline water quality conditions……………………………………………………… 25 Figure 10. Comparison of forecasted sensitive species richness for the Baseline scenario and Grassland Scenario……………………………………………. 26 Figure 11. Estimated improvement in top predator fish populations as a result of a simulated 20% reduction in nutrients and sediments...……………………... 34 Figure 11. Threat index for subwatersheds……………………………………………... 35 Figure 12. Potential relationships between reductions in agricultural inputs and improvements in stream fish communities………………………………….. 36 Figure 13. Forecasted biological conditions in conservation scenarios………………… 39 Figure 14. Forecasted environmental benefits of conservation scenarios………………. 40 Figure 15. Return on investment of conservation scenarios…………………………….. 42 Figure 16. Relationships between stream biological benefits and reductions in agricultural inputs………………………………………………………………………….. 46 Figure 17. Histograms of average changes in biological conditions that occurred within subwatersheds from reductions in agricultural inputs………………… 48 Figure 18. Example of subwatersheds identified as potential priorities for agricultural conservation practices………………………………………………………… 49 Figure 19. Forecasted reductions in nutrient and sediment loading to Lake Erie in conservation scenarios………………………………………………………... 51 Figure 20. Comparison of environmental benefits for Lake Erie and streams ………….. 52 v EXECUTIVE SUMMARY Improving the environmental sustainability of agriculture is essential to ensuring the long-term cultural, economic, and ecological well-being of the Great Lakes region. Nowhere in the region is this more apparent than in the watershed of the Western Lake Erie Basin (WLEB). An estimated 5.5 million acres of cropland exist in the WLEB, making it the most intensively farmed watershed in the Great Lakes Basin. Agriculture is fundamental to maintaining the quality of life of many people living in the WLEB and helps feed many people living outside the region. However, non-point source pollution from intensive agriculture threatens aquatic ecosystems and the essential ecosystem services that they provide. Thus, farming practices that allow for continued agricultural production without degrading the surrounding ecosystem are needed in the WLEB. Strong support currently exists in the WLEB to increase investment in agricultural conservation practices (CPs) to improve water quality in Lake Erie and its tributaries. These practices offer the potential to improve water quality by reducing sediments and nutrients from agricultural fields, while also maintaining soil quality and farm profitability. While large investments in CPs have been made over the past several decades, the cumulative benefits of these investments for aquatic ecosystems are poorly understood at the watershed-scale and how much additional investment might be needed to achieve meaningful environmental benefits is unclear, both at present and with continued climate change. This information is vital for strategic conservation in the WLEB. In a large agricultural watershed, such as the WLEB, strategic conservation means getting the right CPs to the right places in the right amount to achieve realistic ecological and water quality outcomes. The goal of our project was to provide WLEB decision-makers with the scientific information needed to make informed decisions about the use of CPs for stream conservation, primarily, and secondarily for water quality in Lake Erie proper. Specifically, we coupled a state- of-the-art hydrology model for the WLEB watershed with robust predictive biological models to quantify how CPs may improve water quality and benefit stream fish communities, using meaningful measures of stream health. Our project built upon previous work in the Saginaw Bay watershed to better understand how much conservation is enough and what the associated costs would be to achieve meaningful benefits for stream ecosystems in the WLEB. We also sought to identify areas within the watershed where CPs would provide the most benefit and to understand to what extent targeted nutrient reductions for Lake Erie (e.g., 40% reduction in total phosphorus) would benefit stream ecosystems. Our results highlight the integral role that CPs could have for improving agricultural sustainability in the WLEB. Agricultural runoff

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