Abstract
Landscape-level spatial estimates of soil water content are critical to understanding ecological processes and predicting watershed response to environmental change. Because soil moisture influences are highly variable at the landscape scale, most meteorological datasets are not detailed enough to depict spatial trends in the water balance at these extents. We propose a tactical approach to gather high-resolution field data for use in soil moisture models. Using these data, we (1) describe general soil moisture trends for a 6400 ha watershed in the Oregon Western Cascades, USA (2) use this description to identify environmental variables to stratify across in collecting data for a statistical explanatory model of soil moisture spatial pattern at the onset of seasonal drought, and (3) examine the spatial scale of variability in soil moisture measurements compared to the scale of variability in potential explanatory factors. The results indicate that soil moisture dynamics and controls are different for different soil depths across this mountainous watershed. Soil moisture variability exhibits complex spatial patterns that can be partially estimated (up to 50 percent of the variation accounted) with easily measurable climatic and terrain variables. The analysis incorporates both macroscale (climate) and mesoscale (topographic drainage and radiation) influences on the water balance. Without additional data on the distribution of edaphic and biotic factors, we are not able to model the variability of soil moisture at the microscale. The regression approach can be used to extrapolate field measurements across similar topographic areas to examine spatial patterns in forest vegetation and moisture-controlled ecological processes.
Similar content being viewed by others
References
Band L.E., Patterson P., Nemani R. and Running S.W. 1993. Forest ecosystem processes at the watershed scale: incorporating hillslope hydrology. Agricultural and Forest Meteorology 63: 93–126.
Barry R.G. 1992. Mountain Weather and Climate. Routledge, London, UK.
Beers T.W., Dress P.E. and Wensel L.C. 1966. Aspect transformation in site productivity research. Journal of Forestry 64: 691–692.
Beven K. and Kirkby M.J. (eds), 1993. Channel Network Hydrology. Wiley, Chichester, UK.
Beven K.J. and Kirkby M.J. 1979. A physically based, variable contributing area model of basin hydrology. Hydrologic Science Bulletin 24: 43–69.
Boyer D.G, Wright R.J., Winant W.M. and Perry H.D. 1990. Soil water relations on a hilltop cornfield in central Appalachia. Soil Science 149: 383–392.
Brady N.C. and Weil R.R. 1999. The Nature and Properties of Soils. Prentice Hall, Upper Saddle River, New Jersey, USA.
Christensen N.L., Bartuska A.M., Brown J.H., Carpenter S., D’Antonio C., Francis R., Franklin J.F., MacMahon J.A., Noss R.N., Parsons D.J., Peterson C.H., Turner M.G. and Woodmansee R.G. 1996. The report of the Ecological Society of America committee on the scientific basis for ecosystem management. Ecological Applications 6: 665–691.
Clark J.S. 1990. Landscape interactions among nitrogen mineralization, species composition, and long-term fire frequency. Biogeochemistry 11: 1–22.
Cramer W., Leemans R., Schulze E.D., Bondeau A. and S.R.J. 1999. Data needs and limitations for broad-scale ecosystem modelling. In: Walker B., Steffen W., Canadell J. and Ingram J. (eds), The Terrestrial Biosphere and Global Change: Implications for Natural and Managed Ecosystems. University Press, Cambridge, UK, pp. 88–105.
Crave A. and Gascuel-Odoux C. 1997. The influence of topography on time and space distribution of soil surface water content. Hydrological Processes 11: 203–210.
Daly C., Neilson R.P. and Phillips D.L. 1994. A statistical-topographic model for mapping climatological precipitation over mountainous terrain. Journal of Applied Meteorology 33: 140–158.
D’Odorico P., Ridolfi L., Porporato A. and Rodriguez-Iturbe I. 2000. Preferential states of seasonal soil moisture: The impact of climate flucuations. Water Resources Research 36: 2209–2219.
Dubayah R.C. and Rich P.M. 1995. Topographic solar radiation models for GIS. International Journal of Geographical Information Systems 9: 405–419.
ESRI. ARC/Info 7. 1994. Environmental Systems Research Institute, Inc. Redlands, California, USA.
Franklin J.F. and Dyrness C.T. 1988. Natural Vegetation of Oregon and Washington. Oregon State University Press, Corvallis, Oregon, USA.
Grayson R.B., Western A.W., Chiew F.H.S. and Bloschl G. 1997. Preferred states in spatial soil moisture patterns. Local and non-local controls. Water Resources Research 33: 2897–2908.
Grier C.C. and Logan R.S. 1977. Old-growth Pseudotsuga menziesii communities of a western Oregon watershed: biomass distribution and production budgets. Ecological Monographs 47: 373–400.
Helvey J.D., Hewlett J.D. and Douglass J.E. 1972. Predicting soil moisture in the southern Appalachians. Soil Science Society of America Proceeding 36: 954–959.
Herkelrath W.N., Hamburg S.P. and Murphy F. 1991. Automatic, real-time monitoring of soil moisture in a remote field area with time domain reflectometry. Water Resources Research 27: 857–864.
Iverson L.R., Dale M.E., Scott C.T. and Prasad A., 1997. A GIS-derived integrated moisture index to predict forest composition and productivity of Ohio forests (U.S.A). Landscape Ecology 12: 331–348.
Jenny H. 1980. The Soil Resoure. Springer-Verlag, New York, New York, USA.
Post D.A. and Jones J.A. 2001. Hydrologic regimes of forested, mountainous, headwater basins in New Hampshire, North Carolina, Oregon, and Puerto Rico. Advances in Water Resources 24: 1195–1210.
Legendre P. and Fortin M.J. 1989. Spatial pattern and ecological analysis. Vegetatio 80: 107–138.
Lookingbill T. and Urban D. 2003. Spatial estimation of air temperature differences for landscape-scale studies in montane environments. Agricultural and Forest Meteorology 114: 141–151.
Mackay D.S. and Band L.E. 1997. Forest ecosystem processes at the watershed scale: dynamic coupling of distributed hydrology and canopy growth. Hydrological Processes 11: 1197–1217.
McKee A. 1998. Focus on field stations: Andrews H.J. Experimental Forest. Bulletin of the Ecological Society of America 79: 241–246.
Miller C. and Urban D.L. 1999. Forest pattern, fire, and climatic change in the Sierra Nevada. Ecosystems 2: 76–87.
Moore I.D., Burch G.J. and Mackenzie D.H. 1988. Topographic effects on the distribution of surface water and the location of ephemeral gullies. Transactions of the American Society of Agricultural Engineering 31: 1098–1107.
Moore I.D., Grayson R.B. and Ladson A.R. 1991. Digital terrain modelling: a review of hydrological, geomorphological, and biological applications. Hydrological Processes 5: 3–30.
Neilson R.P. 1991. Climatic constraints and issues of scale controlling regional biomes. In: Holland M.M., Risser P.G. and Naiman R.J. (eds), Ecotones: The Role of Landscape Boundaries in the Management and Restoration of Changing Environments. Chapman and Hall, New York, USA, pp. 31–51.
Nikolov N.T. and Zeller K.F. 1992. A solar radiation algorithm for ecosystem dynamic models. Ecological Modelling 6: 149–168.
Ohmann J.L. and Spies T.A. 1998. Regional gradient analysis and spatial pattern of woody plant communities of Oregon forests. Ecological Monographs 68: 151–182.
Parker A.J. 1982. The topographic relative moisture index: an approach to soil-moisture assessment in mountain terrain. Physical Geography 3: 160–168.
Pastor J. and Post. W.M. 1988. Response of northern forests to CO2-induced chmate change. Nature 334: 55–58.
Phillips D.L., Dolph J. and Marks D. 1992. A comparison of geostatistical procedures for spatial analysis of precipitation in mountainous terrain. Agricultural and Forest Meteorology 58: 119–141.
Richardson C.W. 1981. Stochastic simulation of daily precipitation, temperature and solar radiation. Water Resources Research 17: 182–190.
Running S.W., Nemani R.R. and Hungerford R.D. 1987. Extrapolation of synoptic meteorological data in mountainous terrain and its use for simulating forest evapotranspiration and photosynthesis. Canadian Journal of Forest Research 17: 472–483.
Sokal R.R. and Rohlf R.J. 1995. Biometry. Freeman, San Francisco, California, USA.
Smith J. 2002. Mapping the Thermal Climate of the H.J. Andrews Experimental Forest, Oregon. Oregon State University, Corvallis, Oregon, USA.
Stephenson N.L. 1990. Climatic controls on vegetation distribution: the role of the water balance. American Naturalist 135: 649–670.
Stephenson N.L. 1998. Actual evapotranspiration and deficit: biologically meaningful correlates of vegetation distribution across spatial scales. Journal of Biogeography 25: 855–870.
Urban D.L., Miller C., Halpin P.N. and Stephenson N.L. 2000. Forest gradient response in Sierran landscapes: the physical template. Landscape Ecology 15: 603–620.
Vertessy R.A., Hatton T.J., Benyon R.G. and Dawes W.R. 1996. Long-term growth and water balance predictions for a mountain ash (Eucalyptus regnans) forest catchment subject to clear-felling and regeneration. Tree Physiology 16: 221–232.
Western A.W., G. Bloschl and Grayson R.B. 1998. How well do indicator variograms capture the spatial connectivity of soil moisture? Hydrological Processes 12: 1851–1868.
Yeakley J.A., Swank W.T., Swift L.W., Hornberger G.W. and Shugart H.H. 1998. Soil moisture gradients and controls on a southern Appalachian hillslope from drought through recharge. Hydrology and Earth System Sciences 2: 41–49.
Zobel D.B., McKee A., Hawk G.M. and Dyrness C.T. 1976. Relationships of environment to composition, structure, and diversity of forest communities of the central western Cascades of Oregon. Ecological Monographs 46: 135–156.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Lookingbill, T., Urban, D. An empirical approach towards improved spatial estimates of soil moisture for vegetation analysis. Landscape Ecol 19, 417–433 (2004). https://doi.org/10.1023/B:LAND.0000030451.29571.8b
Issue Date:
DOI: https://doi.org/10.1023/B:LAND.0000030451.29571.8b