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Perspectives on the Nature and Definition of Ecological Regions

Abstract

Among environmental managers, recognition of the importance of integrating management activities across agencies and programs that have different responsibilities for the same geographic areas has created an awareness of the need for a common hierarchical framework of ecological regions (ecoregions) to implement the strategy. Responding to this need in the United States, nine federal agencies have signed a memorandum of understanding on the subject of developing a common framework of ecoregions. However, considerable disagreement over how to define ecoregions and confusion over the strengths and limitations of existing frameworks stand in the way of achieving this goal. This paper presents some perspectives on the nature and definition of ecoregions related to this confusion and provides a brief overview of the weight of evidence approach to mapping ecoregions, using an example initiated by the US Environmental Protection Agency. To effectively implement ecosystem assessment, management, and research at local, regional, and national levels, research is needed to increase our understanding of ecoregions. We must find ways to illustrate the nature of ecoregion boundaries and the variability of characteristics within ecoregions as they relate to management issues. Research must also be conducted on comparing existing frameworks and developing indices of ecological integrity to effectively evaluate their usefulness.

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Literature Cited

  1. J. E. Anderson (1991) ArticleTitleA conceptual framework for evaluating and quantifying naturalness Conservation Biology 5 347–352 Occurrence Handle10.1111/j.1523-1739.1991.tb00148.x

    Article  Google Scholar 

  2. R. G. Bailey (1988) ArticleTitleProblems with using overlay mapping for planning and their implications for geographic information systems Environmental Management 12 11–17 Occurrence Handle10.1007/BF01867373

    Article  Google Scholar 

  3. M. Beckoff (2000) ArticleTitleRedecorating nature: deep science, holism, feeling, and heart Bioscience 50 635

    Google Scholar 

  4. Box, T. W. 1994. Sustainable ecological systems and cultural change. Pages 2–9 in Sustainable ecological systems: implementing an ecological approach to land management. USDA Forest Service, General Technical Report, RM-247, rocky Mountain forest and range Experiment Station, Fort Collins, CO

  5. Bryce, S. A., J. M. Omernik, D. E. Pater, M. Ulmer, J. Schaar, J. Freeouf, R. Johnson, P. Kuck, S. H. Azevedo. 1998. Ecoregions of North Dakota and South Dakota. Two-sided color poster with map, descriptive text, summary tables, and photographs). U.S. Geological Survey, Reston, Virginia. Scale 1:1,500,000.

  6. S. A. Bryce J. M. Omernik D. P. Larsen (1999a) ArticleTitleEcoregions: A geographic framework to guide risk characterization and ecosystem management Environmental Practice 1 141–155 Occurrence Handle10.1017/S1466046600000582

    Article  Google Scholar 

  7. S. A. Bryce D. P. Larsen R. M. Hughes P. R. Kaufmann (1999b) ArticleTitleAssessing relative risks to aquatic ecosystems: A Mid-Appalachian case study Journal of the American Water Resources Association 35 23–36

    Google Scholar 

  8. CEC (Commission for Environmental Cooperation). 1997. Ecological regions of North America: Toward a common perspective. Commission for Environmental Cooperation, Montreal, Quebec, Canada, 71 pp.

  9. Chapman, S. S., J. M. Omernik, J. A. Freeouf, D. G. Huggins, J. R. McCauley, C. C. Freeman, G. Steinauer, R. T. Angelo, and R. L. Schlepp. 2001. Ecoregions of Nebraska and Kansas. (Two-sided color poster with map, descriptive text, summary tables, and photographs). U.S. Geological Survey, Reston, Virginia. Scale1:1,950,000.

  10. Davis, W. S., B. D. Snyder, J. B. Stribling, and C. Stoughton. 1996. Summary of state biological assessment programs for streams and wadeable rivers. EPA 230-R-96-007. U.S. Environmental Protection Agency, Office of Policy, Planning, and Evaluation, Washington, D.C.

  11. J. W. Fitzpatrick (2002) ArticleTitleThe AOU and bird conservation: Recommitment to the revolution The Auk 119 907–913

    Google Scholar 

  12. A. L. Gallant T. R. Whittier D. P. Larsen J. M. Omernik R. M. Hughes (1989) Regionalization as a tool for managing environmental resources EPA/600/3–89/060. U.S. Environmental Protection Agency, Corvallis Environmental Research Laboratory Corvallis, Oregon 152

    Google Scholar 

  13. Gallant, A. L., E. F. Binnian, J. M. Omernik, and M. B. Shasby. 1995. Ecoregions of Alaska. U.S. Geological Survey Professional Paper 1567. U.S. Government Printing Office, Washington, D.C., 73 pp.

  14. Gauthier, D. A., and E. B. Wiken. 2003. Monitoring the conservation of grassland habitats, prairie ecozone, Canada. Journal of Ecological Monitoring and Assessment, 8(1): 343–364

    Google Scholar 

  15. G. E. Griffith J. M. Omernik A. J. Woods (1999) ArticleTitleEcoregions, watersheds, basins, and HUCs: How state and federal agencies frame water quality Journal of Soil and Water Conservation 54 666–677

    Google Scholar 

  16. Griffith, G. E., J. M. Omernik, J. A. Comstock, S. Lawrence, G. Martin, A. Goddard, V. J. Hulcher, and T. Foster. 2001. Ecoregions of Alabama and Georgia. Two-sided color poster with map, descriptive text, summary tables, and photographs). U.S. Geological Survey, Reston, VA, scale 1:1,700,000.

  17. C. S. Holling (1996) ArticleTitleSurprise for science, resilience for ecosystems, and incentives for people Ecological Applications 6 733–735 Occurrence Handle10.2307/2269475

    Article  Google Scholar 

  18. B. D. Hudson (1992) ArticleTitleThe soil survey as a paradigm-based science Soil Science Society of America Journal 56 836–841 Occurrence Handle10.2136/sssaj1992.03615995005600030027x

    Article  Google Scholar 

  19. R. M. Hughes D. P. Larsen J. M. Omernik (1986) ArticleTitleRegional reference sites: A method for assessing stream potentials Environmental Management 10 629–635 Occurrence Handle1:CAS:528:DyaL28Xlt1Shu78%3D Occurrence Handle10.1007/BF01866767

    CAS  Article  Google Scholar 

  20. R. M. Hughes (1995) Defining acceptable biological status by comparing with reference conditions W. Davis T. Simon (Eds) Biological assessment and criteria: Tools for water resources planning and decision making Lewis Publishers Boca Raton, Florida

    Google Scholar 

  21. J. R. Karr (1993) ArticleTitleDefining and assessing ecological integrity: Beyond water quality Environmental Toxicology and Chemistry 12 1521–1531 Occurrence Handle1:CAS:528:DyaK3sXmtlegtb0%3D

    CAS  Google Scholar 

  22. J. K. Kay E. Schneider (1994) ArticleTitleEmbracing complexity: The challenge of the ecosystem approach Alternatives 20 32–39

    Google Scholar 

  23. G. M. Lewis (1966) ArticleTitleRegional ideas and reality in the Cis-Rocky Mountain West Transactions of the Institute of British Geographers 38 135–150

    Google Scholar 

  24. T.R. Loveland J.W. Merchant J. F. Brown D. O. Ohlen B. C. Reed P. Olsen J. Hutchinson (1995) ArticleTitleSeasonal land-cover regions of the United States Annals of the Association of American Geographers 85 339–355 Occurrence Handle10.1111/j.1467-8306.1995.tb01798.x

    Article  Google Scholar 

  25. T. R. Loveland T. L. Sohl S. V. Stehman A. L. Gallant K. L. Sayler D. E. Napton (2002) ArticleTitleA strategy for estimating the rates of recent United States land cover changes Photogrammetric Engineering and Remote Sensing 68 1091–1099

    Google Scholar 

  26. V. H. Marin (1997) ArticleTitleGeneral system theory and the ecological concept Bulletin of the Ecological Society of America 77 102–104

    Google Scholar 

  27. J. R. McDonald (1994) ArticleTitleReview of “Moving regions’ and ‘Stuck in the region’: Changing scales for regional identity.” Annals of the Association of American Geographers 84 532–533

    Google Scholar 

  28. M. J. McDonnell S. T. A., (eds.) Pickett (1993) Humans as components of ecosystems Springer-Verlag New York 356

    Google Scholar 

  29. McGrath, C. L., A. J. Woods, J. M. Omernik, S. A. Bryce, M. Edmondson, J. A. Nesser, J. Sheldon, R. C. Crawford, J. A. Comstock, and M. D. Plocher. 2001. Ecoregions of Idaho. (Two-sided color poster with map, descriptive text, summary tables, and photographs). U.S. Geological Survey, Reston, Virginia. Scale 1:1,350,000.

  30. I. L. McHarg (1997) ArticleTitleNatural factors in planning Journal of Soil and Water Conservation 52 13–17

    Google Scholar 

  31. G. McMahon S. M. Gregonis S. W. Walton J. M. Omernik T. D. Thorson J. A. Freeouf A. H. Rorick J. E. Keys (2001) ArticleTitleDeveloping a spatial framework of common ecological regions for the conterminous United States Environmental Management 28 293–316 Occurrence Handle1:STN:280:DC%2BD3MvovVemtg%3D%3D Occurrence Handle10.1007/s0026702429

    CAS  Article  Google Scholar 

  32. T. J. O’Connell L. E. Jackson R. P. Brooks (1998) ArticleTitleA bird community index of biotic integrity for the Mid-Atlantic Highlands Environmental Monitoring and Assessment 51 145–156 Occurrence Handle10.1023/A:1005914714813

    Article  Google Scholar 

  33. J. M. Omernik (1987) ArticleTitleEcoregions of the conterminous United States Annals of the Association of American Geographers 77 118–125 Occurrence Handle10.1111/j.1467-8306.1987.tb00149.x

    Article  Google Scholar 

  34. J. M. Omernik (1995) Ecoregions: A spatial framework for environmental management W. S. Davis T. P. Simon (Eds) Biological assessment and criteria: Tools for water resource planning and decision making Lewis Publishing Boca Raton, Florida

    Google Scholar 

  35. J. M. Omernik (2003) ArticleTitleThe misuse of hydrologic unit maps for extrapolation, reporting, and ecosystem management Journal of the American Water Resources Association 39 563–573

    Google Scholar 

  36. J. M. Omernik R. G. Bailey (1997) ArticleTitleDistinguishing between watersheds and ecoregions Journal of the American Water Resources Association 33 1–15

    Google Scholar 

  37. Omernik, J. M., and A. L. Gallant. 1990. Defining regions for evaluating environmental resources. Pages 936–947 in Proceedings of the Global Natural Resource Monitoring and Assessment Symposium, Preparing for the 21st Century. Venice, Italy, September 24–30, 1989.

  38. J. M. Omernik G. E. Griffith (1991) ArticleTitleEcological regions vs. hydrologic units: Frameworks for managing water quality Journal of Soil and Water Conservation 46 334–340

    Google Scholar 

  39. J. M. Omernik C. F. Powers (1983) ArticleTitleTotal alkalinity of surface waters—a national map Annals of the Association of American Geographers 73 133–135 Occurrence Handle10.1111/j.1467-8306.1983.tb01400.x

    Article  Google Scholar 

  40. J. M. Omernik S. S. Chapman R. A. Lillie R. T. Dumke (2000) ArticleTitleEcoregions of Wisconsin Transactions of the Wisconsin Academy of Sciences, Arts, and Letters 88 77–103

    Google Scholar 

  41. T. H. Ricketts E. Dinerstein D. M. Olson C. J. Loucks W. Eichbaum (1999) Terrestrial ecoregions of North America: A conservation assessment Island Press Washington, D.C. 485

    Google Scholar 

  42. C. M. Rohm J. M. Omernik A. J. Woods J. L. Stoddard (2002) ArticleTitleRegional characteristics of nutrient concentrations in streams and their application to nutrient criteria development Journal of the American Water Resources Association 38 213–239 Occurrence Handle1:CAS:528:DC%2BD38XislCltrY%3D

    CAS  Google Scholar 

  43. S. Rossum S. Lavin (2000) ArticleTitleWhere are the Great Plains? A cartographic analysis Professional Geographer 52 543–552 Occurrence Handle10.1111/0033-0124.00245

    Article  Google Scholar 

  44. Salwasser, H., and R. D. Pfister. 1994. Ecosystem management: from theory to practice. Pages 150–161 in Sustainable ecological systems: Implementing an ecological approach to land management. USDA Forest Service, general technical report RM-257, Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO

  45. D. J. Schaeffer E. E. Herricks H. W. Kerster (1988) ArticleTitleEcosystem health: I. Measuring ecosystem health Environmental Management 12 445–455 Occurrence Handle10.1007/BF01873258

    Article  Google Scholar 

  46. M. A. Shirazi C. B. Johnson J. M. Omernik D. White P. K. Haggerty G. E. Griffith (2003) ArticleTitleQuantitative soil descriptions for ecoregions of the United States Journal of Environmental Quality 32 550–561 Occurrence Handle1:CAS:528:DC%2BD3sXkslChurY%3D Occurrence Handle10.2134/jeq2003.0550

    CAS  Article  Google Scholar 

  47. US EPA (Environmental Protection Agency). 1998. National strategy for the development of regional nutrient criteria. EPA 822-R-98-002. U.S. Environmental Protection Agency, Office of Water, Washington, D.C., 589 pp.

  48. US EPA (Environmental Protection Agency). 2003. Level III ecoregions of the continental United States (revision of Omernik 1987). U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Western Ecology Division, Corvallis, Oregon.

  49. US GAO (General Accounting Office). 1994. Ecosystem management: Additional actions needed to test a promising approach. GAO/RCED-94-111. U.S. General Accounting Office, Washington, D.C. 87 pp.

  50. J. E. Vogelmann S. M. Howard L. Yang C. R. Larson B. K. Wylie J. N. Van Driel (2001) ArticleTitleCompletion of the 1990’s national land cover data set for the conterminous United States Photogrammetric Engineering and Remote Sensing 67 650–662

    Google Scholar 

  51. Whittier, T. R., D. P. Larsen, R. M. Hughes, C. M. Rohm, A. L. Gallant, and J. M. Omernik. 1987. The Ohio stream regionalization project: A compendium of results. EPA/600/3-87/025. U.S. Environmental Protection Agency, Environmental Research Laboratory, Corvallis, Oregon, 68 pp.

  52. D. Wicklum R. W. Davis (1995) ArticleTitleEcosystem health and integrity Canadian Journal of Botany 73 997–1000

    Google Scholar 

  53. Wiken, E. B. 1986. Terrestrial ecozones of Canada. Environment Canada. Ecological Land Classification Series No. 19, Ottawa, Ontario, 26 pp.

  54. Wiken, E. B. 1997. State of the environment reporting in Canada and North America: An overview of the concepts and applications. Pages C13–C18 in Proceedings of the First National Workshop on the State of the Environment Reporting Workshop. SOER occasional paper no. 1. ISBN: 0-797401744-3. Government of the Republic of Zimbabwe, Ministry of the Environment and Tourism, Harare, Zimbabwe.

  55. E. B. Wiken (1999) ArticleTitleMeasuring up responsibility: Assessing protected areas through state of the environment reporting and indicators The George Wright Forum 16 14–21

    Google Scholar 

  56. Woods, A. J., D. A. Lammers, S. A. Bryce, J. M. Omernik, R. L. Denton, M. Domeier, and J. A. Comstock. 2001. Ecoregions of Utah. (Two-sided color poster with map, descriptive text, summary tables, and photographs). US Geological Survey, Reston, Virginia. Scale 1:1,175,000.

  57. S. L. Yaffee (1999) ArticleTitleThree faces of ecosystem management Conservation Biology 13 713–725 Occurrence Handle10.1046/j.1523-1739.1999.98127.x

    Article  Google Scholar 

  58. Zonneveld, I. S. 1988. Landscape ecology and its application. Pages 3–15 in Moss, M. (ed.), Landscape ecology and management. Proceedings of the First Symposium of the Canadian Society for Landscape Ecology and Management: University of Guelph, May, 1987. Polyscience Publications Inc., Montreal, Canada.

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Acknowledgments

I am grateful to Jerry McMahon, Glenn Griffith, and Susan Christie for their helpful reviews. I also thank Tom Loveland for encouraging me to write this paper. The information in this paper has been funded by the US Environmental Protection Agency and the US Geological Survey. It has been subjected to review by the US EPA National Health and Environmental Effects Research Laboratory’s Western Ecology Division peer review process and approved for publication. Approval does not signify that the contents reflect the views of the Agency.

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Correspondence to James M. Omernik.

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Omernik, J. Perspectives on the Nature and Definition of Ecological Regions. Environmental Management 34, S27–S38 (2004). https://doi.org/10.1007/s00267-003-5197-2

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  • DOI: https://doi.org/10.1007/s00267-003-5197-2

  • Ecoregions
  • Ecological regions
  • Ecology
  • Ecosystems
  • Ecosystem management
  • Regionalization
  • Environment