, Volume 19, Issue 4, pp 716–732 | Cite as

Wetland restoration: The potential for assembly rules in the service of conservation

  • Paul Keddy


One of the pressing problems for applied ecologists is the efficeint restoration of structure and function to degraded ecosystems. Where some other conservation activities, such as protection of existing wilderness, continue to require making the best of increasingly bad situations, the goal of restoration raises the pleasing prospect of measurable improvement in landscapes. Restoration simultaneously provides the ultimate test for the discipline of community ecology: ecologists should be able to build an ecosystem in the same way an engineer builds a bridge, with a list of parts connected in specified ways leading to certain reliable outcomes. Failures would reveal that scientists do not adequately understand the system. Practical considerations suggest the application of tools that already exist rather than the invention of new ones. The objective of this paper is to suggest that two valuable tools may already exist, tools that provide an intellectual foundation for restoration ecology. Such a foundation is necessary because there has been a tendency for restoration ecology to represent a haphazard collection of individual cases rather than a well-defined discipline with repeatable methods. One possible scheme for unifying studies of restoration is that provided by assembly rules, where predictions are based upon key environmental factors and the responses of species to those factors. The potential of such assembly rules is introduced using three examples: fish in wetlands, plants in salt marshes, and plants in prairie potholes. I then describe an experiment where a standard species pool of wetland plants was sown into twenty-four different sets of environmental conditions, illustrating how landscapes can select communities out of larger pools. A second possible tool is indicators of ecosystem integrity. These can measure whether a project actually works. Clear discrimination between success and failure can improve restoration procedures by accelerating the evolution of management principles and techniques; Holling has called this process ‘adaptive environmental assessment.’ I conclude with the optimistic view that restoration already has the tools for continued progress; what is needed is primarily their intelligent application. That is, rather than ending with a typically academic plea for more research, I suggest (for a change) that what is needed is only the discriminating application of procedures and principles that already exist.

Key Words

Amazon River assembly rules environmental filters eutrophication fertility fish hydrology indicators Lythrum salicaria prairie potholes management restoration seed banks salt marshes species pools tactics traits wetlands 


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Literature Cited

  1. Adam, P. 1990. Saltmarsh Ecology. Cambridge University Press, Cambridge, UK.Google Scholar
  2. Adams, G. D. 1988. Wetlands of the prairies of Canada. p. 158–198.In Wetlands of Canada. National Wetlands Working Group. Ecological Land Classification Series. No. 24. Sustainable Development Branch, Environment Canada. Ottawa, Ontario, Canada. and Polyscience Publications Inc., Montreal, Quebec, Canada.Google Scholar
  3. Adamus, P. R. 1992. Choices in monitoring wetlands. p. 571–592.In D. H. McKenzie, D. E. Hyatt, and V. J. McDonald (eds) Ecological Indicators. Elsevier Applied Science, London, UK.Google Scholar
  4. Batt, B. D. J., M. G. Anderson, C. D. Anderson, and F. D. Caswell. 1989. The use of prairie potholes by North American ducks. p. 204–227.In A. G. van der Valk (ed.) Northern Prairie Wetlands. Iowa State University Press, Ames, IA, USA.Google Scholar
  5. Bauder, E. T. 1989. Drought stress and competition effects on the local distribution ofPogogyne abramsii. Ecology 70:1083–1089.Google Scholar
  6. Beanlands, G. E. and P. N. Duinker. 1983. An ecological framework for environmental impact assessment in Canada. Institute for Resource and Environmental Studies Dalhousie University and Federal Environmental Assessment Review Office. Halifax, Nova Scotia, Canada.Google Scholar
  7. Beard, J. S. 1949. The Natural Vegetation of the Windward & Leeward Islands. Clarendon Press, Oxford, UK.Google Scholar
  8. Bégin, Y., S. Arseneault, and J. Lavoie. 1989. Dynamique d’une bordure forestière par suite de la hausse récente du niveau marin, rive sud-ouest du Golfe du Saint-Laurent, Nouveau-Brunswick. Géographie Physique et Quaternaire 43:355–366.Google Scholar
  9. Belkin, D. A. 1963. Anoxi: tolerance in reptiles. Science 139:492–493.PubMedGoogle Scholar
  10. Bertness, M. D. 1991. Interspecific interactions among high marsh perennials in a New England salt marsh. Ecology 72:125–137.Google Scholar
  11. Bertness, M. D. and S. D. Hacker. 1994. Physical stress and positive associations among marsh plants. The American Naturalist 144: 363–372.Google Scholar
  12. Bertness, M. D., and G. H. Leonard. 1997. The role of positive interactions in communities: Lessons from intertidal habitats. Ecology 78:1976–1989.Google Scholar
  13. Bertness, M. D., L. Gough, and S. W. Shumway. 1992. Salt tolerances and the distribution of fugitive salt marsh plants. Ecology 73:1842–1851.Google Scholar
  14. Bloom, S. A. 1980. Multivariate quantification of community recovery. p. 141–151.In J. Cairns (ed.) The Recovery Process in Damaged Ecosystems. Ann Arbor Science Publishers, Ann Arbor, MI, USA.Google Scholar
  15. Boesch, D. F., M. N. Josselyn, A. J. Mehta, J. T. Morris, W. K. Nuttle, C. A. Simenstad, and D. P. J. Swift. 1994. Scientific Assessment of Coastal wetland loss, restoration and management in Louisiana. Journal of Coastal Research, Special Issue No. 20. Coastal Education and Research Foundation, Lawrence, KS, USA.Google Scholar
  16. Bolen, E. G., L. M. Smith, and H. L. Schramm, Jr. 1989. Playa lakes: prairie wetlands of the southern High Plains. BioScience 39:615–623.Google Scholar
  17. Bonnicksen, T. M. 1988. Restoration ecology: philosophy, goals and ethics. The Environmental Professional 10:25–35.Google Scholar
  18. Boutin, C., and P. A. Keddy. 1993. A functional classification of wetland plants. Journal of Vegetation Science 4:591–600.Google Scholar
  19. Cairns, J. (ed.). 1980. The Recovery Process in Damaged Ecosystems. Ann Arbor Science Publishers, Ann Arbor, MI, USA.Google Scholar
  20. Cairns, J. 1989. Restoring damaged ecosystems: is predisturbance condition a viable option? The Environmental Professional 11: 152–159.Google Scholar
  21. Cairns, J., Jr., B. R. Niederlehner, and D. R. Orvos. 1992. Predicting Ecosystem Risk. Advances in Modern Environmental Toxicology, Vol. XX. Princeton Scientific Publishing Company, Princeton, NJ, USA.Google Scholar
  22. Carpenter, J. F., J. R. Kitchell, P. A. Hodgson, J. J. Cochran, M. M. Elser, D. M. Elser, D. Lodge, X. He. Kretchmer, and C. N. von Ende. 1987. Regulation of lake primary productivity by food web structure. Ecology 68:1863–1876.Google Scholar
  23. Castellanos, E. M., M. E. Figueroa and A. J. Davy. 1994. Nucleation and facilitation in saltmarsh succession: Interactions betweenSpartina maritima andArthrocnemem perenne. Journal of Ecology 82:239–248.Google Scholar
  24. Chung, C. 1982. Low marshes, China. p. 131–145.In R.R. Lewis III (ed.) Creation and Restoration of Coastal Plant Communities. CRC Press, Boca Raton. FL, USA.Google Scholar
  25. Clements, F. E. 1935. Experimental ecology in the public service. Ecology 16:342–363.Google Scholar
  26. Cummins, K. W. 1973. Trophic relationships of aquatic insects. Annual Review of Entomology 18:83–206.Google Scholar
  27. Cummins, K. W. and M. J. Klug. 1979. Feeding ecology of stream invertebrates. Annual Review of Ecology and Systematics 10: 147–172.Google Scholar
  28. Diamond, J. M. 1975. Assembly of species communities. p. 342–444.In M. L. Cody and J. M. Diamond (eds.) Ecology and Evolution of Communities. Belknap Press, Harvard University Press, Cambridge, MA, USA.Google Scholar
  29. Dore, W. G. and J. McNeill. 1980. Grasses of Ontario. Monograph 26, Research Branch, Agriculture Canada, Ottawa, Ontario, Canada.Google Scholar
  30. Drake, J. A. 1990. Communities as assembled structures: do rules govern pattern? Trends in Ecology and Evolution 5:159–164.Google Scholar
  31. Eriksson, O. 1993. The species-pool hypothesis and plant community diversity. Oikos 68:371–374.Google Scholar
  32. Essame, H. 1974. Patton. A Study in Command. Scribner’s, New York, NY, USA.Google Scholar
  33. Freedman, B. 1995. Environmental Ecology (2nd ed.). Academic Press, San Diego, CA, USA.Google Scholar
  34. Frey, R. W., and P. B. Basan. 1978. Coastal salt marshes. p. 101–169.In R. A. Davis (ed.) Coastal Sedimentary Environments, Springer-Verlag, New York, NY, USA.Google Scholar
  35. Galatowitsch, S. M. and A. G. van der Valk. 1994. Restoring Prairie Wetlands: An Ecological Approach. Iowa State University Press, Ames, IA, USA.Google Scholar
  36. Galatowitsch, S. M. and A. G. van der Valk. 1996. The vegetation of restored and natural prairie wetlands. Ecological Applications 6:102–112.Google Scholar
  37. García, L. V., T. Marañón, A. Moreno, and L. Clemente. 1993. Above-ground biomass and species richness in a Mediterranean salt marsh. Journal of Vegetation Science 4:417–424.Google Scholar
  38. Glooschenko, W. A. 1980. Coastal ecosystems of the James/Hudson Bay area of Ontario. Canada. Zeitschrift fuer Geomorphologie N.F. 34:214–224.Google Scholar
  39. Gough, L. G., J. B. Grace, and K. L. Taylor. 1994. The relationship between species richness and community biomass: the importance of environmental variables. Oikos 70:271–279.Google Scholar
  40. Gleason, H. A. and A. Cronquist. 1963. Manual of Vascular Plants of the Northeastern United States and Adjacent Canada. Willard Grant, Boston, MA, USA.Google Scholar
  41. Goldsmith, F. B. (ed.). 1991. Monitoring for Conservation and Ecology. Chapman and Hall, London, UK.Google Scholar
  42. Goulding, M. 1980. The Fishes and the Forest: Explorations in Amazonian Natural History. University of California Press, Berkley, CA, USA.Google Scholar
  43. Grace, J. B. and D. Tilman. (eds.) 1990. Perspectives on Plant Competition. Academic Press, San Diego, CA, USA.Google Scholar
  44. Grime, J. P., and R. Hunt. 1975. Relative growth rate: its range and adaptive significance in a local flora. Journal of Ecology 63:393–422.Google Scholar
  45. Grime, J. P., G. Mason, A. V. Curtis, J. Rodman, S. R. Band, M. A. G. Mowforth A. M. Neal, and S. Shaw. 1981. A comparative study of germination characteristics in a local flora. Journal of Ecology 69:1017–1059.Google Scholar
  46. Gurevitch, J., L. Morrow, A. Wallace, and J. Walsh. 1992. A meta-analysis of competition in field experiments. The American Naturalist 140:539–572.Google Scholar
  47. Hoagland, B. W., and S. L. Collins. 1997. Heterogeneity in short-grass prairie vegetation: the role of playa lakes. Journal of Vegetation Science 8:277–286.Google Scholar
  48. Holling, C. S. (ed.) 1978. Adaptive Environmental Assessment and Management. International Institute for Applied Systems Analysis, John Wiley and Sons, Chichester, UK.Google Scholar
  49. Hughes, L., M. Dunlop, K. French, M. R. Leishman, B. Rice, L. Rodgerson, and M. Westoby. 1994. Predicting dispersal spectra: a minimal set of hypotheses based on plant attributes. Journal of Ecology 82:933–950.Google Scholar
  50. Jefferies, R. L. 1988. Pattern and process in Arctic coastal vegetation in response to foraging by lesser snow geese. p. 281–300.In M. J. A. Werger, P. J. M. van der Aart, H. J. During, and J. T. A. Verhoeven. Plant Form and Vegetation Structure. SPB Academic Publishing, The Hague, The Netherlands.Google Scholar
  51. Jones, C. G., J. H. Lawton, and M. Shachak. 1994. Organisms as ecosystem engineers. Oikos 69:373–386.Google Scholar
  52. Jones, R. K., G. Pierpoint, G. M. Wickware, J. K. Jeglum, R. W. Arnup, and J. M. Bowles. 1983. Field Guide to Forest Ecosystem Classification for the Clay Belt, Site Region 3e. Ontario Ministry of Natural Resources, Thunder Bay, Ontario, Canada.Google Scholar
  53. Jordan, W. R., M. E. Gilpin, and J. D. Aber. 1987. Restoration Ecology. A Synthetic Approach to Ecological Research. Cambridge University Press, Cambridge, UK.Google Scholar
  54. Junk, W. J. 1984. Ecology of thevarzea, floodplain of Amazonian white-water rivers. p. 215–243.In H. Sioli (ed.) The Amazon Limnology and Landscape Ecology of a Mighty Tropical River and its Basin. Junk Publishers, Dordrecht, The Netherlands.Google Scholar
  55. Junk, W. J., M. G. M. Soares, and U. Saint-Paul. 1997. The Fish. The Central Amazon Floodplain. Ecological Studies 126:385–408.Google Scholar
  56. Kantrud, H. A., J. B. Millar, and A. G. van der Valk. 1989. Vegetation of the wetlands of the prairie pothole region. p. 132–187.In A. G. van der Valk (ed.) Northern Prairie Wetlands. Iowa State University Press, Ames, IA, USA.Google Scholar
  57. Keddy, C. J., and T. McCrae. 1989. Environmental databases for State of the Environment Reporting: Conservation and Protection Head Quarters. State of the Environment Reporting Branch, Environment Canada, Ottawa, Ontario, Canada. Technical Report No. 19.Google Scholar
  58. Keddy, P. A. 1976. Lakes as islands: the distributional ecology of two aquatic plants,Lemna minor L. andL. trisulca L. Ecology 57:163–359.Google Scholar
  59. Keddy P. A. 1989. Competition. Chapman and Hall, London, UK.Google Scholar
  60. Keddy, P. A. 1991. Biological monitoring and ecological prediction: from nature reserve management to national state of the environment indicators. p. 249–267.In F. B. Goldsmith (ed.) Monitoring for Conservation and Ecology. Chapman and Hall, London, UK.Google Scholar
  61. Keddy, P. A. 1992. Assembly and response rules: two goals for predictive community ecology. Journal of Vegetation Science 3: 157–164.Google Scholar
  62. Keddy, P. A. 1999. Epilogue: from global exploration to community assembly. p. 393–402.In E. Weiher, and P. A. Keddy (eds.) Ecological Assembly Rules: Perspectives, Advances, Retreats. Cambridge University Press, Cambridge, UK.Google Scholar
  63. Keddy, P. A., and A. A. Reznicek. 1986. Great Lakes vegetation dynamics: the role of fluctuating water levels and buried seeds. Journal of Great Lakes Research 12:25–36.Google Scholar
  64. Keddy, P. A., H. T. Lee, and I. C. Wisheu. 1993. Choosing indicators of ecosystem integrity: Wetlands as a model system. p. 61–79.In S. Woodley, J. Kay, and G. Francis (eds.) Ecological Integrity and the Management of Ecosystems. St. Lucie Press, Delray Beach, FL, USA.Google Scholar
  65. Keddy, P. A., L. H. Fraser, and I. C. Wisheu. 1998. A comparative approach to examine competitive response of 48 wetland plant species. Journal of Vegetation Science 9:777–786.Google Scholar
  66. Keddy, P. A. and E. Weiher. 1999. Introduction: the scope and goals of research on assembly rules. p. 1–20.In E. Weiher and P. A. Keddy (eds.) Ecological Assembly Rules: Perspectives, Advances, Retreats. Cambridge University Press, Cambridge, UK.Google Scholar
  67. Keogh, T. M., P. Keddy, and L. H. Fraser. 1999. Patterns of tree species richness in forested wetlands. Wetlands 19:639–647.Google Scholar
  68. Kramer, D. L., C. C. Lindsay, G. E. E. Moodie, and E. D. Stevens. 1978. The fishes and the aquatic environment of the Central Amazon basins, with particular reference to respiratory patterns. Canadian Journal of Zoology 56:717–729.Google Scholar
  69. Kusler, J. A. and M. E. Kentula. (eds.). 1990. Wetland Creation and Restoration: Status of the Science. Island Press, Washington, DC, USA.Google Scholar
  70. Lane, P. A. 1985. A food web approach to mutualism in lake communities. p. 344–374.In D. H. Boucher (ed.) The Biology of Mutualism. Ecology and Evolution. Oxford University Press, New York, NY, USA.Google Scholar
  71. Larson, D. W. 1996. Brown’s Woods: an early gravel pit forest restoration project, Ontario, Canada. Restoration Ecology 4:11–18.Google Scholar
  72. Levine, J., J. S. Brewer, and M. D. Bertness. 1998. Nutrients, competition and plant zonation in a New England salt marsh. Journal of Ecology. 86:285–292.Google Scholar
  73. Lewontin, R. C. 1974. The Genetic Basis of Evolutionary Change. Columbia University Press, New York, NY, USA.Google Scholar
  74. Lockwood, J. L. and S. L. Pimm. 1999. When does restoration succeed? p. 363–392.In E. Weiher and P. A. Keddy (eds.) Ecological Assembly Rules: Perspectives, Advances, Retreats. Cambridge University Press, Cambridge, UK.Google Scholar
  75. Lodge, D. M. 1991. Herbivory on freshwater macrophytes. Aquatic Botany 41:195–224.Google Scholar
  76. Lowe-McConnell, R. H. 1975. Fish Communities in Tropical Freshwaters. Their Distribution, Ecology and Evolution. Longman, London, UK.Google Scholar
  77. MacArthur, R. H. and E. O. Wilson. 1967. The Theory of Island Biogeography. Monographs in Population Biology. No. 1. Princeton University Press, Princeton, NJ, USA.Google Scholar
  78. Magnuson, J. J., C. A. Paszkowski, F. J. Rahel, and W. M. Tonn. 1989. Fish ecology in severe environments of small isolated lakes in Northern Wisconsin. p. 487–515.In R. Sharitz and J. W. Gibbons (eds.) Freshwater Wetlands and Wildlife. USDOE Office of Scientific and Technical Information, Oak Ridge, TN, USA. Conf-8603101, DOE symposium Series No 61.Google Scholar
  79. McKenzie, D. H., D. E. Hyatt, and V. J. McDonald. 1992. Ecological Indicators Vols. 1 & 2. Elsevier, London, UK.Google Scholar
  80. Meave, J., M. Kellman, A. MacDougall, and J. Rosales. 1991. Riparian habitats as tropical refugia. Global Ecology and Biogeography Letters 1:69–76.Google Scholar
  81. Michener, W. K., E. R. Blood, K. L. Bildstein, M. M. Brinson, and L. R. Gardner. 1997. Climate change, hurricanes and tropical storms, and rising sea level in coastal wetlands. Ecological Applications 7:770–801.Google Scholar
  82. Niering, W. A. and R. S. Warren. 1980. Vegetation patterns and processes in New England salt marshes. Bioscience 30:301–307.Google Scholar
  83. Noss, R. 1995. Maintaining Ecological Integrity in Representative Reserve Networks. A World Wildlife Fund Canada/World Wildlife Fund United States Discussion Paper. World Wildlife Fund, Toronto, ON, Canada.Google Scholar
  84. Odum, E. P. 1985. Trends expected in stressed ecosystems. BioScience 35:419–422.Google Scholar
  85. Partridge, T. R., and J. B. Wilson. 1987. Salt tolerance of salt marsh plants of Otago, New Zealand. New Zealand Journal of Botany 25:559–566.Google Scholar
  86. Phipps, R. W. 1883. On the Necessity of Preserving and Replanting Forests. Blackett and Robinson, Toronto, Ontario, Canada.Google Scholar
  87. Pfadenhauer, O. J. and F. Klotzli. 1996. Restoration experiments in middle European wet terrestrial ecosystems: an overview. Vegetatio 126:101–115.Google Scholar
  88. Racey, G. D., A. G. Harris, J. K. Jeglum, R. F. Foster, and G. M. Wickware. 1996. Terrestrial and Wetland Ecosites of Northwestern Ontario. Ontario Ministry of Natural Resources, Thunder Bay, Ontario, Canada. NWST Field Guide FG-02.Google Scholar
  89. Rapport, D. J., C. Thorpe, and T. C. Hutchinson. 1985. Ecosystem behavior under stress. American Naturalist 125:617–640.Google Scholar
  90. Rapport, D. J. 1989. What constitutes ecosystem health? Perspectives in Biology and Medicine 33:120–132.Google Scholar
  91. Rigler, F. H. 1982. Recognition of the possible: An advantage of empiricism in ecology. Canadian Journal of Fisheries and Aquatic Sciences 39:1323–1331.Google Scholar
  92. Rigler, R. T., and R. H. Peters. 1995. Science and Limnology. Ecology Institute, Oldendorf, Germany.Google Scholar
  93. Schoener, T. W. 1983. Field experiments on interspecific competition. The American Naturalist 122:240–285.Google Scholar
  94. Schoener, T. W. 1985. Some comments on Connell’s and my reviews of field experiments on interspecific competition. The American Naturalist 125:730–740.Google Scholar
  95. Sculthorpe, C. D. 1967. The Biology of Aquatic Vascular Plants. Reprinted in 1985 by Edward Arnold, London, UK.Google Scholar
  96. Severinghaus, W. D. 1981. Guild theory development as a mechanism for assessing environmental impact. Environmental Management 5:187–190.Google Scholar
  97. Shaffer, G. P., C. E. Sasser, J. G. Gosselink, and M. Rejmanck. 1992. Vegetation dynamics in the emerging Atchafalaya Delta, Lousiana, USA. Journal of Ecology 80:677–687.Google Scholar
  98. Sheail, J. and T. C. E. Wells. 1983. The fenlands of Huntingdonshire, England: A case study in catastrophic change. p. 375–393.In A. J. P. Gore (ed.) Ecosystems of the World 4B. Mires: Swamp, Bog, Fen and Moor. Elsevier, Amsterdam, The Netherlands.Google Scholar
  99. Shay, J. M. and C. T. Shay. 1986. Prairie marshes in western Canada, with specific reference to the ecology of live emergent macrophytes. Canadian Journal of Botany 64:443–454.Google Scholar
  100. Shipley, B., P. A. Keddy, D. R. J. Moore, and K. Kemky. 1989. Regeneration and establishment strategies of emergent macrophytes. Journal of Ecology 77:1093–1110.Google Scholar
  101. Simberloff, D. and T. Dayan. 1991. The guild concept and the structure of ecological communities. Annual Review of Ecology and Systematies 22:115–143.Google Scholar
  102. Smith, L. M. and J. A. Kadlec. 1985. Fire and herbivory in a Great Salt Lake marsh. Ecology 66:259–265.Google Scholar
  103. Snow, A. A. and S. W. Vince. 1984. Plant zonation in an Alaskan salt marsh II: An experimental study of the role of edaphic conditions. Journal of Ecology 72:669–684.Google Scholar
  104. Steneck, R. S. and M. N. Dethier. 1994. A functional group approach to the structure of algal-dominated communities. Oikos 69:476–498.Google Scholar
  105. Sykes, M. T. and J. B. Wilson. 1989. The effect of salinity on the growth of some New Zealand sand dune species. Acta Botanica Neerlandica 38:173–182.Google Scholar
  106. Tansley, A. G. 1914. Presidential Address. Journal of Ecology 2: 194–203.Google Scholar
  107. Thorson, T. and A. Svihla. 1943. Correlations of the habitats of amphbians with their ability to survive the loss of body water. Ecology 24:374–381.Google Scholar
  108. Tomlinson, P. B. 1986. The Botany of Mangroves. Cambridge University Press, Cambridge, UK.Google Scholar
  109. Tonn, W. M., and J. J. Magnuson. 1982. Patterns in the species composition and richness of fish assemblages in northern Wisconsin lakes. Ecology 63:1149–1166.Google Scholar
  110. Twolan-Strutt, L. and P. A. Keddy. 1996. Above- and below-ground competition intensity in two contrasting wetland plant communities. Ecology 77:259–270.Google Scholar
  111. Underwood, T. 1986. The analysis of competition by field experiments. p. 240–268.In J. Kikkawa and D. J. Anderson (eds.) Community Ecology. Pattern and Process. Blackwell, Melbourne, Australia.Google Scholar
  112. van der Valk, A. G. 1981. Succession in wetlands: a Gleasonian approach. Ecology 62:688–696.Google Scholar
  113. van der Valk, A. G. 1988. From community ecology to vegetation management: providing a scientific basis for management. p. 463–470.In Transactions of the Fifty-third North American Wildlife and Natural Resources Conference, Wildlife Management Institute, Washington, DC, USA.Google Scholar
  114. van der Valk, A. G. and C. B. Davis. 1978. The role of scedbanks in the vegetation dynamics of prairie glacial marshes. Ecology 59: 322–335.Google Scholar
  115. Walker, B. H. and C. F. Wehrhahn. 1971. Relationships between derived vegetation gradients and measured environmental variables in Saskatchewan wetlands. Ecology 52:85–95.Google Scholar
  116. Weiher, E. and P. A. Keddy. 1995. The assembly of experimental wetland plant communities. Oikos 73:323–335.Google Scholar
  117. Weiher, E. and P. A. Keddy. 1999. Ecological Assembly Rules: Perspecitives, Advances, Retreats. Cambridge University Press, Cambridge, UK.Google Scholar
  118. Weiher, E., I. C. Wisheu, P. A. Keddy, and D. R. J. Moore. 1996. Establishment, persistence, and management implications of experimental wetland plant communities. Wetlands 16:208–218.Google Scholar
  119. Weinberg, G. M. 1975. An Introduction to General Systems Thinking. John Wiley and Sons, New York, NY, USA.Google Scholar
  120. Weins, J. A. 1983. Avian community ecology: an iconoclastic view. p. 355–403.In A. H. Brush and G. A. Clark, Jr. (eds.) Perspectives in ornithology. Essays presented for the centennial of the American Ornithologists’ Union. Cambridge University Press, Cambridge, UK.Google Scholar
  121. Whittaker, R. J. and S. H. Jones. 1994. Structure in re-building insular ecosystems: an empirically derived model. Oikos 69:524–529.Google Scholar
  122. Wilbur, H. M. 1984. Complex life cycles and community organization in amphibians. p. 195–225.In P. W. Price, C. N. Slobodchikoff, and W. S. Gaud (eds.) A New Ecology: Novel Approaches to Interactive Systems. Wiley and Sons, New York, NY, USA.Google Scholar
  123. Wild Earth. 1992. The Wildlands Project. Special Issue. Wild Earth, Tucson, AZ, USA.Google Scholar
  124. Woodley, S., J. Kay, and G. Francis (eds.) 1993. Ecological Integrity and the Management of Ecosystems. St. Lucie Press, Delray Beach, FL, USA.Google Scholar
  125. Woodwell, G. M. and R. H. Whittaker. 1968. Effects of chronic gamma irradiation on plant communities. The Quarterly Review of Biology 43:42–55.PubMedGoogle Scholar
  126. Zedler, J. B. and C. P. Onuf. 1984. Biological and physical filtering in arid-region estuaries: seasonality, extreme events, and effects of watershed modification. p. 415–432.In V. S. Kennedy (ed.) The Estuary as a Filter. Academic Press, New York, NY, USA.Google Scholar
  127. Zedler, J. B. and P. A. Beare. 1986. Temporal variability of salt marsh vegetation: the role of low-salinity gaps and environmental stress. p. 295–306.In D. A. Wolfe (ed.) Estuarine Variability. Academic Press, San Diego, CA, USA.Google Scholar
  128. Zhulidov, A. V., J. V. Headley, R. D. Roberts, A. M. Nikanorov, and A. A. Ischenko. 1997. Atlas of Russian Wetlands. Environment Canada, National Hydrology Research Institute, Saskatoon, Saskatchewan, Canada.Google Scholar
  129. Zobel, M. 1997. The relative role of species pools in determining plant species richness: an alternative explanation of species coexistence? Trends in Ecology and Evolution 12:266–269.Google Scholar

Copyright information

© Society of Wetland Scientists 1999

Authors and Affiliations

  • Paul Keddy
    • 1
  1. 1.Department of BiologyUniversity of OttawaOttawaCanada
  2. 2.Edward G. Schlieder Endowed Chair for Environmental Studies Department of Biological SciencesSoutheastern Louisiana UniversityHammondUSA

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