ECOLOGICAL SITE DESCRIPTIONS

Main Points

1. Ecological site descriptions replace the traditional range site descriptions that focused primarily on forage production in favor of ecological site descriptions that include vegetation dynamics and broader resource uses and values as well as forage production.
2. Soils with like properties that produce and support a characteristic plant community and respond similarly to management are grouped into the same ecological site.
3. Ecological sites are differentiated one from another based on 1) significant differences in species or species groups, 2) significant differences in species composition, and 3) differences in productivity, and 4) soil factors that influence species composition or productivity (NRCS 2003).

Map of Major Land Resource Areas (MLRA)

Oak-Woodland & Annual Grassland Ecological Site Descriptions

Information Sources

1. NRCS (Natural Resources Conservation Service). 2003. National Pasture and Range Handbook, Rev. 1. Grazinglands Technical Institute, USDA Natural Resources Conservation Service. (http://www.glti.nrcs.usda.gov/technical/publications/nrph.html).
2. Ecological Site Description (ESD) System for Rangeland and Forestland Data http://esis.sc.egov.usda.gov/Welcome/pgReportLocation.aspx\

State and Transition Models - General Concepts and Methods

1. Bestelmeyer, Brandon, Joel R. Brown, Kris M. Havstad, Robert Alexander, George Chavez and Jeffery Herrick. 2003. Development and use of state-and-transition models for rangelands.
2. Briske, D.D., S.D. Fuhlendorf, and F.E. Smeins. 2005. State-and-transition models, thresholds, and rangeland health: A synthesis of ecological concepts and perspectives. Rangeland Ecology and Management 58:1-10.
3. Stringham, Tamzen K., William C. Krueger, and Patrick L. Shaver. 2003. State and transition modeling: An ecological process approach. J. Range Management 56:106-113.
4. Stringham, Tamzen K., William C. Krueger, and Patrick L. Shaver. 2001. State, transitions, and thresholds: Further refinement for rangeland application. Agric. Exper. Sta., Oregon State Univ. Spec. Rep 1024.
5. Westoby, Mark, Brian Walker and Imanuel Noy-Meir. 1989. Opportunistic management for rangelands at equilibrium. J. Range Management 42:266-274.

State and Transition Models - Oak Woodlands

1. George, M.R.; J.R. Brown, W.J. Clawson. 1992. Application of nonequilibrium ecology to management of Mediterranean grasslands. J. Range Management 45:436-440.
2. Huntsinger, L., and J. W. Bartolome. 1992. A state transition model of the ecological dynamics of Quercus dominated woodlands in California and southern Spain. Vegetation 99-100:299-305.
3. Jackson, Randall D. and James W. Bartolome. 2002. A state-transition approach to understanding nonequibibrium plant community dynamics in Californian grasslands. Plant Ecology 162: 49-65.