1. COG, 9 June 2009 1 Assessing the Consequences of Land Use Change in the Upper Potomac Robert H. Gardner with Jason Julian, Andrew J. Elmore, Todd R. Lookingbill, Marcella Suarez-Rubio Appalachian Laboratory University of Maryland Center for Environmental Science

2. COG, 9 June 2009 2 The Appalachian Laboratory To “… determine the effects of natural and human- induced changes on organisms, landscapes, and biogeochemical and hydrological cycles.”

3. COG, 9 June 2009 3 Outline 1.Importance of land-use and land-cover (LULC) change in the Potomac River Basin 2.The challenge of determining effects 3.An integrated approach for prediction

4. COG, 9 June 2009 4 1. Importance of LULC change LULC is accelerating and is global in extent Directly linked with declines in –Biodiversity –Water quality and availability –Ecosystem productivity (especially economically important species) LULC may also –Accelerate climate change –Enhance the spread of disease (new pandemics)

5. COG, 9 June 2009 5 Basin: 38,000 km 2 Mainstem: 617 km (170 km tidal) 6 physiographic provinces Climate boundary The Potomac River Basin

6. COG, 9 June 2009 6 Key attributes of the PRB Located in one of most rapidly urbanizing areas in the US –5.3 million people w/n basin –Coal mining affects Appalachians –Agriculture in Ridge and Valley –Piedmont and Coastal Plain continue to be urbanized The 617 km river main stem has relatively unregulated flows

7. COG, 9 June 2009 7 History of LULC change Not glaciated – but glacial runoff produced coastal plain & Chesapeake Bay Frontier stage – (17 th century) –natural resource use, local deforestation Agricultural Expansion – (18 th century) –Pops of 380,000 –20-30% of forests cleared –Sediment accumulation in Bay affect navigation http://www.chesapeakebay.net/history.htm

8. COG, 9 June 2009 8 More history Industrialization – (late 18 th century) –Urban corridor formed –Population of 2.5 million, raw sewerage in Bay –Railroads consume 15-20 million acres of Eastern Deciduous Forest Population expansion – (19 th century) –Beginning of environmental legislation and control (Clean Air Act, etc.)

9. COG, 9 June 2009 9 Effects of LULC within the Potomac Hardened surfaces result in buried streams with increased throughput –Nutrient retention declines, export increases Population growth increases water demands –From Upper Potomac to Lower Ecosystem recovery from wide variety of disturbances remains unknown New invasives impact terrestrial and aquatic habitats

10. COG, 9 June 2009 10 The problem of buried streams

11. COG, 9 June 2009 11 The gradient of population density

12. COG, 9 June 2009 12 Lower Potomac >> Upper Potomac

13. COG, 9 June 2009 13 Low-flow correlated with high demand Lookingbill et al., in press Low flow frequencyLow flow demand 112 year record shows 13% of years have extremely low flows

14. COG, 9 June 2009 14 Invasive organisms are here to stay –Gypsy moth –Hemlock wooly adelgid –Chestnut blight New (potential) –Emerald ash borer has been found in MD –Sirex noctilio – wasp (horntail) kills pines –Sudden oak death –Asian long horned beetle (in MD)

15. COG, 9 June 2009 15 Potomac River Ecosystem has not been adequately studied RiverISI References Columbia3,263 Mississippi2,921 Colorado2,195 Hudson1,193 Missouri826 Potomac309

16. COG, 9 June 2009 16 2. Determining effects Landscapes are composed of many “elements” including … –roads –agricultural “units” –forests of diverse types and ages –urban & suburban development And diverse economic conditions

17. COG, 9 June 2009 17 We know that the spatial arrangement of “elements” is critical Riparian buffers effectively reduce sediment and nutrient export While development selectively removes headwaters ecosystems * No single sub-watershed is representative of the Potomac Small critical areas (wetlands) are most effective nutrient and sediment filters * Elmore and Kaushal, 2008

18. COG, 9 June 2009 18 Effects of LULC are not additive If linear then effects of change are additive –we can extrapolate using mean value(s) –landscape assessment can be produced by simple summation (spread sheet) –or by sampling extremes (boundaries) and interpolating for each set of unique conditions

19. COG, 9 June 2009 19 “Many challenges remain in extending our understanding of how hydrologic processes within small catchments scale to larger river basins.” The problem of scale

20. COG, 9 June 2009 20 Critical thresholds: Brook trout density and impervious cover Stranko et al. 2008

21. COG, 9 June 2009 21 Disturbance induces time lags Disturbances are not simple transient events? –History of change is important We may not be able to predict the future from the past Forest harvesting has altered age and species distribution of flora –Decline (possibly permanent declines) in oak and pine abundance

22. COG, 9 June 2009 22 Eshleman et al. 2005 Significant effects on nutrient cycling

23. COG, 9 June 2009 23 AMD Permanent effects of coal mining

24. COG, 9 June 2009 24 3. An integrated, predictive approach Understanding -> prediction But this requires: Spatial and temporal characterization of weather patterns Determination of trends in land use change A process-based representation considers interactive effects of multiple changes Estimation of unknowns and uncertainties

25. COG, 9 June 2009 25 Interactive effects are important? Flood potential – is a combined effect of LULC and climate change Denitrification – depends on the location of critical habitat placement –Sources and sinks –Effectiveness of restoration Meeting water quality demands –A moving target: growth, development, LULC and climate change

26. COG, 9 June 2009 26 SLEUTH: a model of land-use change USGS sponsored development –Slope, Land use, Exclusion, Urban extent, Transportation, Hillshade – Clark (1998) Being explored and widely used w/n Chesapeake Watershed A pattern-based model –Uses a fine-scale, gridded landscape –Projects urban growth

27. COG, 9 June 2009 27 Historical records are necessary Required GIS layers –Urban growth (3-4 layers) –Roads (2 layers) –Exclusion (1 layer) – protected lands –Hillshade (1 layer) –Slope (1 layer) –Land use (1 layer) – current

28. COG, 9 June 2009 28 Empirical (best fit) of 5 growth parameters govern probability of urbanization Spontaneous dispersion – formation of new urban locations Growth (increase in size) of new urban locations Growth of old (established) locations Road gravity – increased growth rates near roads Slope resistance – decreased growth with increasing slope Dietzel (2007)

29. COG, 9 June 2009 29 Calibration first Brute force calibration (inefficient) –Parameters varied over broad range –Monte Carlo techniques applied –Subset (“best fit”) determined by spatial comparison to history of change

30. COG, 9 June 2009 30 Prediction requires Current land use maps for initialization –Urban extent –Transportation network –Exclusion layer Future scenarios performed by varying –Exclusion layer (e.g., streams, etc.) And exclusion “rules” –Constraints on transportation network

31. COG, 9 June 2009 31 Baltimore-Washington projections (Jantz et al. 2003) Three scenarios for piedmont & coastal plain of Maryland and Northern Virginia Variable exclusion layers developed –By state and land use type Scenarios: A. Current trends B. Managed growth C. Ecological preservation

32. COG, 9 June 2009 32 Results Change (km 2 / y) ScenarioUrbanForestAgriculture A. Current trends 110-43-51 B. Managed growth 41-15 C. Ecological preservation 28-10-9

33. COG, 9 June 2009 33 Summary Moderate “exclusions” have large effects on patterns of LULC change Population trends continue to drive change Model improvements always desirable –Local policies not yet implemented Linkage of land use projections with ecosystem models urgently needed –Water, nutrients, sediments as a function of land-use change –Biotic effects of land-use change

34. COG, 9 June 2009 34 Our efforts for the Potomac We have spent ~1 year on data acquisition, verification Calibration has been performed Simulations begun on development scenarios in the Upper Potomac –Focus on effects of habitat change on bird community (Ph.D. thesis)

35. COG, 9 June 2009 35 Next steps This summer –Plans for a workshop at Appalachian Lab Include relevant parties using SLEUTH w/n Chesapeake Share “mutual” resources (data layers) Apply uniform methods for calibration and prediction – for cross-comparisons Shared effort – data enhancement, model improvement

36. COG, 9 June 2009 36 Special thanks Sujay Kaushal Walter Boynton Tom Fisher Larry Sanford Jeff Cornwell Bill Dennison Clair Jantz