Contact Information
  • Ecoregions
  • Robert G. Bailey
  • Rocky Mountain Research Station
  • 240 W Prospect Rd
  • Fort Collins, CO 80526 USA
  • (970) 498-2617
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Journal Articles

Bailey, Robert G. Identifying Ecoregion Boundaries. 2004. Environmental Management 34(Supplement 1):S14-S26.

Summarizes the rationale used in identifying ecoregion boundaries on maps of the United States, North America, and the world's continents, published from 1976 to 1998. The geographic reasoning used in drawing boundaries involves 20 principles, which are presented to stimulate discussion and further understanding.

Omernik, James M.; Bailey, Robert G. Distinguishing Between Watersheds and Ecoregions. 1997. Journal of the American Water Resources Association 33(5):935-949.

Many state and federal agencies have begun using watershed or ecoregion frameworks. Misunderstanding of each of the frameworks has resulted in inconsistency in their use and ultimate effectiveness. The focus of this paper is on the clarification of both frameworks. The issue is not whether to use watersheds or ecoregions frameworks, but how to correctly use the frameworks together.

Bailey, Robert G. Description of the ecoregions of the United States (2nd ed.). 1995. Misc. Pub. No. 1391, Map scale 1:7,500,000. USDA Forest Service.

This publication briefly describes and illustrates the Nation's ecosystem regions as shown on the map Ecoregions of the United States. A copy of this map is provided with the publication. The description of each region includes a discussion of land-surface form, climate, vegetation, soils, and fauna.

Bailey, Robert G. Design of Ecological Networks for Monitoring Global Change. 1991. Environmental Conservation 18(2):173-175.

World-wide monitoring of agricultural and other natural-resource ecosystems is needed in assessing the effects of possible climate changes and/or air pollution on our global resource-base. Monitoring of all sites is neither possible nor desirable for large areas, and so a means of choice has to be devised and implemented.

Bailey, Robert G. Ecogeographic Analysis. 1988. USDA Forest Service: Misc Publication 1465.

Ecological units of different sizes for predictive modeling of resource productivity and ecological response to management need to be identified and mapped. A set of criteria for subdividing a landscape into ecosystem units of different sizes is presented, based on differences in factors important in differentiating ecosystems at varying scales in a hierarchy. Practical applications of such units are discussed.

Bailey, Robert G. Problems with Using Overlay Mapping for Planning and Their Implications for Geographic Information Systems. 1988. Environmental Management 12(1):11-17.

As part of the planning process, maps of natural factors are often superimposed in order to identify areas which are suitable or unsuitable for a particular type of resource management. Current interest in applying computer-assisted mapping technology is drawing attention to geographic information systems. The resultant maps, however, may be so inaccurate that they could lead to imperfect or false conclusions. Recommendations are made on how to proceed in light of these problems.

Bailey, Robert G. Suggested Hierarchy of Criteria for Multiscale Ecosystem Mapping. 1987. Landscape and Urban Planning 14:313-319.

Ecological units of different size suited to the kinds of questions being asked at different levels of management decisions need to be identified and mapped. A set of criteria for sub-dividing a landscape into ecosystems of different size is presented, based on differences in factors important in controlling ecosystem size at varying scales in a hierarchy.

Bailey, Robert G. The Factor of Scale in Ecosystem Mapping. 1985. Environmental Management 9(4):271-276.

Ecosystems come in many scales or relative sizes. The relationships between smaller and larger scales must be examined in order to predict the effects of management prescriptions on resource outputs. Environmental factors important in controlling ecosystem size change in nature with the scale of observation. Environmental factors that are thought to be useful in recognizing and mapping ecosystems at various scales are reviewed.

Bailey, Robert G. Testing an Ecosystem Regionalization. 1984. Journal of Environmental Management 19:239-248.

As a means of developing reliable estimates of ecosystem productivity, landscapes need to be stratified into homogeneous geographic regions. Such ecosystem regions are hypothesized to be productively different in important ways. One measure of the difference is hydrologic productivity. Data from 53 hydrologic bench-mark stations within major ecosystem regions were subjected to discriminant analysis. The ecosystem regions tested in this study exhibit a high degree of ability to circumscribe stations with similar hydrologic productivity.

Bailey, Robert G. Delineation of Ecosystem Regions. 1983. Environmental Management 7(4):365-373.

As a means of developing reliable estimates of ecosystem productivity, ecosystem classification needs to be placed within a geographical framework of regions or zones. This paper explains the basis for the regions delineated on the 1976 map Ecoregions of the United States. Four ecological levels are discussed — domain, division, province, and section — based on climatic and vegetational criteria. Statistical tests are needed to verify and refine map units.

Bailey, Robert G. Land-Capability Classification of the Lake Tahoe Basin, California-Nevada. 1974.

The prospect of increased land development in the Lake Tahoe basin emphasizes the need for better criteria for planning and executing development. Land capability classes are established to guide regional planning and development. Land tolerance is used as the principal measure of capability. Two types of factors are used to rate capability or tolerance: soil type and geomorphic setting. The type and intensity of land use consistent with natural limitations are suggested for each capability class. Limits on land-surface modification are expressed as a percentage of each area that can be used for impervious cover.