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Restoration Ecology and Invasive Plants in the Semiarid West

Published online by Cambridge University Press:  20 January 2017

Cynthia S. Brown*
Affiliation:
Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, CO 80523 Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO 80523
Val J. Anderson
Affiliation:
Plant and Animal Sciences, Brigham Young University, Provo, UT, 84602
Victor P. Claassen
Affiliation:
Land Air and Water Resources, University of California, Davis, CA 95616
Mark E. Stannard
Affiliation:
U.S. Department of Agriculture Plant Materials Center, Pullman, WA 99164
Linda M. Wilson
Affiliation:
Invasive Plant Management Program, British Columbia Ministry of Agriculture and Lands, Abbotsford, BC, Canada V3G2M3
Sheryl Y. Atkinson
Affiliation:
Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, CO 80523 Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO 80523
James E. Bromberg
Affiliation:
Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, CO 80523 Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO 80523
Thomas A. Grant III
Affiliation:
Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO 80523
Marques D. Munis
Affiliation:
Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, CO 80523
*
Corresponding author's E-mail: [email protected]

Abstract

Invasive plants are a common problem in the management and restoration of degraded lands in the semiarid western United States, but are often not the primary focus of restoration ecologists. Likewise, restoring native vegetation has not been a major concern of weed scientists. But trends in the literature demonstrate increasing overlap of these fields, and greater collaboration between them can lead to improved efficacy of restoration efforts. Succession and ecosystem development are the products of complex interactions of abiotic and biotic factors. Our greatest restoration and invasive plant management successes should result when we take advantage of these natural processes. Recent shifts in management objectives have generated approaches to directing plant community development that utilize species that are strong competitors with invasive species as a bridge to the establishment of native perennial vegetation. Soil water and nutrient characteristics and their interactions can affect desired and undesired plant species differentially and may be manipulated to favor establishment and persistence of desired perennial plant communities. Selection of appropriate plant materials is also essential. Species assemblages that suppress or exclude invaders and competitive plant materials that are well adapted to restoration site conditions are important keys to success. We provide guidelines for restoration based on the fundamental ecological principles underlying succession. Knowledge of the complex interactions among the biotic and abiotic factors that affect successional processes and ecosystem development, and increased collaboration between weed scientists and restoration ecologists hold promise for improving restoration success and invasive species management.

Type
Invited Review
Copyright
Copyright © Weed Science Society of America 

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References

Literature Cited

Allen, E. B., Roundy, B. A., McArthur, D. E., Haley, J. S., and Mann, compilers, D. K. 1995. Restoration ecology: limits and possibilities in arid and semiarid lands. Pages 715. in. Proceedings—Wildland Shrub and Arid Land Restoration Symposium. Ogden, UT USDA Forest Service Intermountain Research Station Gen. Tech. Rep. INT-GTR-315.Google Scholar
Allen, E. B. and Allen, M. F. 1984. Competition between plants of different successional stages: mycorrhizae as regulators. Can. J. Bot 62:26252629.Google Scholar
Allen, E. B. and Allen, M. F. 1988. Facilitation of succession by the nonmycotrophic colonizer Salsola kali (Chenopodiaceae) on a harsh site: effects of mycorrhizal fungi. Am. J. Bot 75:257266.CrossRefGoogle Scholar
Allen, E. B., Brown, J. S., and Allen, M. F. 2001. Restoration of plant, animal and microbial diversity. Encyclopedia Biodivers 5:185202.Google Scholar
Ambrose, L. G. and Wilson, S. D. 2003. Emergence of the introduced grass Agropyron cristatum and the native grass Bouteloua gracilis in a mixed-grass prairie restoration. Rest. Ecol 11:110115.CrossRefGoogle Scholar
Baer, S. G., Kitchen, D. J., Blair, J. M., and Rice, C. W. 2002. Changes in ecosystem structure and function along a chronosequence of restored grasslands. Ecol. Appl 12:16881701.Google Scholar
Bakker, J. D. and Wilson, S. D. 2004. Using ecological restoration to constrain biological invasion. J. Appl. Ecol 41:10581064.Google Scholar
Bazzaz, F. A. 1996. Plants in Changing Environments: Linking Physiological, Population, and Community Ecology. Cambridge, UK Cambridge University Press. 320 p.Google Scholar
Belnap, J. and Philips, S. L. 2001. Soil biota in an ungrazed grassland: response to annual grass (Bromus tectorum) invasion. Ecol. Appl 11:12611275.Google Scholar
Booth, D. T. and Vogel, K. P. 2006. Revegetation priorities. Rangelands 28:2430.Google Scholar
Borman, M. M., Johnson, D. E., and Krueger, W. C. 1992. Soil-moisture extraction by vegetation in a Mediterranean maritime climatic regime. Agron. J 84:897904.Google Scholar
Bradshaw, A. D. 1997. What do we mean by restoration. Pages 814. in Urbanska, K. M., Webb, N. R., and Edwards, P. J., editors. Restoration Ecology and Sustainable Development. Cambridge, UK Cambridge University Press.Google Scholar
Briske, D. D., Fuhlendorf, S. D., and Smeins, F. E. 2006. A unified framework for assessment and application of ecological thresholds. Rangeland Ecol. Manag 59:225236.Google Scholar
Brown, C. 2004. Are functional guilds more realistic management units than individual species for restoration. Weed Technol 18:15661571.CrossRefGoogle Scholar
Brown, H. E. and Thompson, J. R. 1965. Summer water use by aspen, spruce, and western Colorado. J. For 63:756760.Google Scholar
Bugg, R. L., Brown, C. S., and Anderson, J. H. 1997. Restoring native perennial grasses to rural roadsides in the Sacramento Valley of California: establishment and evaluation. Restor. Ecol 5:214225.Google Scholar
Cable, D. R. 1977. Seasonal use of soil water by mature velvet mesquite. J. Range Manag 30:411.Google Scholar
Cline, J. F., Uresk, D. W., and Rickard, W. H. 1977. Comparison of soil water used by a sagebrush–bunchgrass and a cheatgrass community. J. Range Manag 30:199201.Google Scholar
Corbin, J. D. and D'Antonio, C. M. 2004. Can carbon addition increase competitiveness of native grasses? A case study from California. Restor. Ecol 12:3643.Google Scholar
Cox, R. D. and Anderson, V. J. 2004. Increasing native diversity of cheatgrass-dominated rangeland through assisted succession. J. Range Manag 57:203210.CrossRefGoogle Scholar
D'Antonio, C. and Meyerson, L. A. 2002. Exotic plant species as problems and solutions in ecological restoration: a synthesis. Restor. Ecol 10:703713.Google Scholar
D'Antonio, C. M. and Vitousek, P. M. 1992. Biological invasions by exotic grasses, the grass/fire cycle, and global change. Annu. Rev. Ecol. Syst 23:6387.CrossRefGoogle Scholar
Davies, K. W., Pokorny, M. L., Sheley, R. L., and James, J. J. 2007. Influence of plant functional group removal on inorganic soil nitrogen concentrations in native grasslands. Rangeland Ecol. Manage 60:304310.Google Scholar
Davis, M. A. and Thompson, K. 2000. Eight ways to be a colonizer; two ways to be an invader: a proposed nomenclature scheme for invasion ecology. Bull. Ecol 81:226230.Google Scholar
Davison, J. and Smith, E. 2005. Living with fire, crested wheatgrass: hero or villain in reclaiming disturbed rangelands University of Nevada Cooperative Extension Fact Sheet 96-53. 4 p.Google Scholar
Dobson, A. P., Bradshaw, A. D., and Baker, A. J. M. 1997. Hopes for the future: restoration ecology and conservation biology. Science 277:515522.Google Scholar
Dodd, M. B., Lauenroth, W. K., and Welker, J. M. 1998. Differential water resource use by herbaceous and woody plant life-forms in a shortgrass steppe community. Oecologia 117:504512.CrossRefGoogle Scholar
Dukes, J. S. 2001. Biodiversity and invasibility in grassland microcosms. Oecologia 126:563568.Google Scholar
Dyer, A. R., Fossum, H. C., and Menke, J. W. 1996. Emergence and survival of Nassella pulchra in a California grassland. Madroño 43:316333.Google Scholar
Dyer, A. R. and Rice, K. J. 1999. Effects of competition on resource availability and growth of a California bunchgrass. Ecology 80:26972710.Google Scholar
Ellstrand, N. C. and Schierenbeck, K. A. 2000. Hybridization as a stimulus for the evolution of invasiveness in plants. Proc. Natl. Acad. Sci. U. S. A. 97:70437050.Google Scholar
Enloe, S. F., DiTomaso, J. M., Orloff, S. B., and Drake, D. J. 2004. Soil water dynamics differ among rangeland plant communities dominated by yellow starthistle (Centaurea solstitialis), annual grasses, or perennial grasses. Weed Sci 52:929935.CrossRefGoogle Scholar
Fargione, J., Brown, C. S., and Tilman, D. 2003. Community assembly and invasion: an experimental test of neutral versus niche processes. Proc. Natl. Acad. Sci U. S. A. 100:89168920.Google Scholar
Floyd, M. L., Hanna, D., Romme, W. H., and Crews, T. E. 2006. Predicting and mitigating weed invasions to restore natural post-fire succession in Mesa Verde National Park, Colorado, USA. Int. J. Wildland Fire 15:247259.Google Scholar
Hansen, M. J. and Wilson, S. D. 2006. Is management of an invasive grass Agropyron cristatum contingent on environmental variation. J. Appl. Ecol 43:269280.Google Scholar
Harris, G. A. 1967. Some competitive relationships between Agropyron spicatum and Bromus tectorum . Ecol. Monogr 37:89111.CrossRefGoogle Scholar
Hawkes, C. V., Belnap, J., D'Antonio, C., and Firestone, M. K. 2006. Arbuscular mycorrhizal assemblages in native plant roots change in the presence of invasive exotic grasses. Plant Soil 281:369380.Google Scholar
Hawkes, C. V., Wren, I. V., Herman, D. J., and Firestone, M. K. 2005. Plant invasion alters nitrogen cycling by modifying the soil nitrifying community. Ecol. Lett 8:976985.CrossRefGoogle ScholarPubMed
Holmes, T. H. and Rice, K. J. 1996. Patterns of growth and soil-water utilization in some exotic annuals and native perennial bunchgrasses of California. Ann. Bot 78:233243.Google Scholar
Hooper, D. U. and Vitousek, P. M. 1998. Effects of plant composition and diversity on nutrient cycling. Ecol. Monogr 68:121149.Google Scholar
Hufford, K. M. and Mazer, S. J. 2003. Plant ecotypes: genetic differentiation in the age of ecological restoration. Trends Ecol. Evol 18:147155.CrossRefGoogle Scholar
Humphrey, L. D. and Schupp, E. W. 2002. Seedling survival from locally and commercially obtained seeds on two semiarid sites. Restor. Ecol 10:8895.Google Scholar
Inouye, R. S. 2006. Effects of shrub removal and nitrogen addition on soil moisture in sagebrush steppe. J. Arid Environ 65:604618.Google Scholar
Jones, T. A. 1998. Viewpoint: the present status and future prospects of squirreltail research. J. Range Manag 51:326331.Google Scholar
Jones, T. A. and Johnson, D. A. 1998. Integrating genetic concepts into planning rangeland seedings. J. Range Manag 51:594606.CrossRefGoogle Scholar
Kardol, P., Bezemer, T. M., and van der Putten, W. H. 2006. Temporal variation in plant–soil feedback controls succession. Ecol. Lett 9:10801088.Google Scholar
Keddy, P. A. 1992. Assembly and response rules—two goals for predictive community ecology. J. Veg. Sci 3:157164.Google Scholar
Keeley, J. E., Baer-Keeley, M., and Fotheringham, C. J. 2005. Alien plant dynamics following fire in Mediterranean-climate California shrublands. Ecol. Appl 15:21092125.Google Scholar
Keeley, J. E., Fotheringham, C. J., and Baer-Keeley, M. 2006. Demographic patterns of postfire regeneration in Mediterranean-climate shrublands of California. Ecol. Monogr 76:235255.CrossRefGoogle Scholar
Knapp, E. E. and Rice, K. J. 1994. Starting from seed: genetic issues in using native grasses for restoration. Restor. Manag. Notes 12:4045.Google Scholar
Knapp, E. E. and Rice, K. J. 1996. Genetic structure and gene flow in Elymus glaucus (blue wildrye): implications for native grassland restoration. Restor. Ecol 4:110.Google Scholar
Kourtev, P. S., Ehrenfeld, J. G., and Haggblom, M. 2003. Experimental analysis of the effect of exotic and native plant species on the structure and function of soil microbial communities. Soil Biol. Biochem 35:895905.CrossRefGoogle Scholar
Kulmatiski, A., Beard, K. H., and Stark, J. M. 2006. Exotic plant communities shift water-use timing in a shrub-steppe ecosystem. Plant Soil 288:271284.CrossRefGoogle Scholar
Lesica, P. and Allendorf, F. W. 1999. Ecological genetics and restoration of plant communities: mix or match. Restor. Ecol 7:4250.Google Scholar
Lesica, P. and DeLuca, T. H. 1996. Long-term harmful effects of crested wheatgrass on Great Plains grassland ecosystems. J. Soil Water Conserv 51:408409.Google Scholar
Lewis, D. J., Singer, M. J., Dahlgren, R. A., and Tate, K. W. 2006. Nitrate and sediment fluxes from a California rangeland watershed. J. Environ. Qual 35:22022211.Google Scholar
Ley, R. E. and D'Antonio, C. M. 1998. Exotic grass invasion alters potential rates of N fixation in Hawaiian woodlands. Oecologia 113:179187.Google Scholar
Luken, J. O. 1990. Directing Ecological Succession. London Chapman and Hall. 118.Google Scholar
Mack, R. N., Simberloff, D., Lonsdale, W. M., Evans, H., Clout, M., and Bazzaz, F. A. 2000. Biotic invasions: causes, epidemiology, global consequences, and control. Ecol. Appl 10:689710.Google Scholar
Mangold, J. and Fansler, V. 2007. Increasing native plant diversity in crested wheatgrass stands. Page 5 in Proceedings of the Society for Ecological Restoration, Northwest Conference.Google Scholar
Masters, R. A. and Nissen, S. J. 1997. Revegetating leafy spurge (Euphorbia esula)–infested rangeland with native tallgrasses. Weed Technol 12:381390.Google Scholar
McLendon, T. and Redente, E. F. 1992. Effects of nitrogen limitation on species replacement dynamics during early succession on a semiarid sagebrush site. Oecologia 91:312317.CrossRefGoogle ScholarPubMed
Millar, C. I. and Libby, W. J. 1989. Disneyland or native ecosystem: genetics and the restorationist. Restor. Manag. Notes 7:1824.Google Scholar
Monson, S. B., McArthur, E. D., Roundy, B. A., McArthur, D. E., Haley, J. S., and Mann, compilers, D. K. 1995. Implications of early intermountain range and watershed restoration practices. Pages 1625. in. Proceedings—Wildland Shrub and Arid Land Restoration Symposium. Ogden, UT USDA Forest Service Intermountain Research Station. Gen. Tech. Rep. INT-GTR-315.Google Scholar
Norton, J. B., Monaco, T. A., Norton, J. M., Johnson, D. A., and Jones, T. A. 2004a. Cheatgrass invasion alters soil morphology and organic matter dynamics in big sagebrush–steppe rangelands. USDA Forest Service Proceedings.Google Scholar
Norton, J. B., Monaco, T. A., Norton, J. M., Johnson, D. A., and Jones, T. A. 2004b. Soil morphology and organic matter dynamics under cheatgrass and sagebrush-steppe plant communities. J. Arid Environ 57:445466.Google Scholar
Paschke, M. W., McLendon, T., and Redente, E. F. 2000. Nitrogen availability and old-field succession in a shortgrass steppe. Ecosystems 3:144158.Google Scholar
Pellant, M. and Lysne, C. R. 2005. Strategies to enhance plant structure diversity in crested wheatgrass seedlings. Pages 6470 in Proceedings of the USDA Forest Service. RMRS-P-38. Fort Collins, CO: Rocky Mountain Research Station.Google Scholar
Pickett, S. T. A., Collins, S. L., and Armesto, J. J. 1987. Models, mechanisms, and pathways of succession. Bot. Rev 53:335371.Google Scholar
Piemeisel, R. L. 1951. Causes affecting change and rate of change in a vegetation of annuals in Idaho. Ecology 32:5372.Google Scholar
Pokorny, M. L., Sheley, R. L., Zabinski, C. A., Engel, R. E., Svejcar, T. J., and Borkowski, J. J. 2005. Plant functional group diversity as a mechanism for invasion resistance. Restor. Ecol 13:448459.Google Scholar
Prach, K., Pysek, P., and Jarosik, V. 2007. Climate and pH as determinants of vegetation succession in Central European man-made habitats. J. Veg. Sci 18:701710.Google Scholar
Pyšek, P. 1995. On the terminology used in plant invasion studies. Pages 7181. in Pyšek, P., Prach, K., Rejmánek, M., and Wade, M., editors. Pant Invasions—General Aspects and Special Problems. Amssterdam SPB Academic.Google Scholar
Richards, R. T., Chambers, J. C., and Ross, C. 1998. Use of native plants on federal lands: policy and practice. J. Range Manag 51:625632.Google Scholar
Rogers, D. L. and Montalvo, A. M. 2004. Genetically Appropriate Choices for Plant Materials to Maintain Biological Diversity. Lakewood, CO University of California Report to the USDA Forest Service, Rocky Mountain Region. 343 p. http://www.fs.fed.us.r2/publications/botany/plantgenetics.pdf. Accessed: May 5, 2007.Google Scholar
Rowe, H. I., Brown, C. S., and Claassen, V. P. 2007. Comparisons of mycorrhizal responsiveness with field soil and commercial inoculum for six native montane species and Bromus tectorum . Restor. Ecol 15:4452.Google Scholar
Sakai, A. K., Allendorf, F. W., Holt, J. S., et al. 2001. The population biology of invasive species. Annu. Rev. Ecol. Syst 32:305332.Google Scholar
Seabloom, E. W., Borer, E. T., Boucher, V. L., Burton, R. S., Cottingham, K. L., Goldwasser, L., Gram, W. K., Kendall, B. E., and Micheli, F. 2003. Competition, seed limitation, disturbance, and reestablishment of California native annual forbs. Ecol. Appl 13:575592.Google Scholar
[SERI] Society for Ecological Restoration International 2004. The SER International Primer on Ecological Restoration. http://www.ser.org/content/ecological_restoration_primer.asp. Accessed: June 29, 2007.Google Scholar
Sheley, R. L. and Carpinelli, M. F. 2005. Creating weed-resistant plant communities using niche-differentiated nonnative species. Rangeland Ecol. Manag 58:480488.Google Scholar
Sheley, R. L. and Krueger-Mangold, J. 2003. Principles for restoring invasive plant-infested rangeland. Weed Sci 51:260265.CrossRefGoogle Scholar
Smith, J. L., Halvorson, J. J., and Bolton, H. 1994. Spatial relationships of soil microbial biomass and C and N mineralization in a semi-arid shrub-steppe ecosystem. Soil Biol. Biochem 26:11511159.Google Scholar
Sperry, L. J., Belnap, J., and Evans, R. D. 2006. Bromus tectorum invasion alters nitrogen dynamics in an undisturbed arid grassland ecosystem. Ecology 87:603615.Google Scholar
Stylinski, C. D. and Allen, E. B. 1999. Lack of native species recovery following severe exotic disturbance in southern Californian shrublands. J. Appl. Ecol 36:544554.Google Scholar
Suding, K. N. and Gross, K. L. 2006. The dynamic nature of ecological systems: multiple states and restoration trajectories. Pages 190209. in Falk, D. A., et al, editor. Foundations of Restoration Ecology. Washington, DC Island.Google Scholar
Tausch, R. J., Chambers, J. C., Blank, R. R., Novak, R. S., Roundy, B. A., McArthur, D. E., Haley, J. S., and Mann, compilers, D. K. 1995. Differential establishment of perennial grass and cheatgrass following fire on an ungrazed sagebrush–juniper site. Pages 252257. in. Proceedings—Wildland Shrub and Arid Land Restoration Symposium. Ogden, UT USDA Forest Service Intermountain Research Station Gen. Tech. Rep. INT-GTR-315.Google Scholar
Temperton, V. M., Hobbs, R. J., Nuttle, T., and Halle, S. 2004. Assembly Rules and Restoration Ecology: Bridging the Gap between Theory and Practice. 1st ed. Washington, DC Island.Google Scholar
Thompson, T. W., Roundy, B. A., McArthur, D. E., Jessop, B. D., Waldron, B. L., and Davis, J. N. 2002. Fire rehabilitation using native and introduced species: a landscape trial. Rangeland Ecol. Manag 59:237248.Google Scholar
Vitousek, P. M., Walker, L. R., Whiteaker, L. D., Mueller-Dombois, D., and Matson, P. A. 1987. Biological invasion by Myrica faya alters ecosystem development in Hawaii. Science 238:802804.Google Scholar
Waldron, B. L., Monaco, T. A., Jensen, K. B., Harrison, R. D., Palazzo, A. J., and Kulbeth, J. D. 2005. Coexistence of native and introduced perennial grasses following simultaneous seeding. Agron. J 97:990996.Google Scholar
Walker, L. R. and del Moral, R. 2003. Primary Succession and Ecosystem Rehabilitation. Cambridge, UK Cambridge University Press.Google Scholar
Walker, L. R., Walker, J., and Hobbs, R. J. 2007. Linking Restoration and Ecological Succession. New York Springer Sciences and Business Media. 190 p.CrossRefGoogle Scholar
Washington State Department of Agriculture, Seed Branch 2005. 2005 Acres Applied for Certification. Little, J. and Shauler, V., compilers. p. 1.Google Scholar
Weiss, S. B. 1999. Cars, cows, and checkerspot butterflies: nitrogen deposition and management of nutrient-poor grasslands for a threatened species. Conserv Biol 13:14761486.Google Scholar
Westerling, A. L., Hidalgo, H. G., Cayan, D. R., and Swetnam, T. W. 2006. Warming and earlier spring increase western US forest wildfire activity. Science 313:940943.Google Scholar
Whisenant, S. G. 1990. Postfire population dynamics of Bromus japonicus . Am. Midl. Nat 123:301308.Google Scholar
Whisenant, S. G. 1999. Repairing Damaged Wildlands: A Process-Oriented Landscape-Scale Approach. Cambridge, UK Cambridge University Press.Google Scholar
Wilson, G. W. T. and Hartnett, D. C. 1998. Interspecific variation in plant responses to mycorrhizal colonization in tallgrass prairie. Am. J. Bot 85:17321738.Google Scholar
Wilson, M. V., Ingersoll, C. A., Wilson, M. G., and Clark, F. L. 2004. Why pest plant control and native plant establishment failed: a restoration autopsy. Nat. Areas J 24:2331.Google Scholar
Young, J. A., Blank, R. R., and Longland, W. S. 1995. Nitrogen enrichment-immobilization to control succession in arid land plant communities. J. Arid Land Stud 5S:5760.Google Scholar
Young, J. A., Trent, J. D., Blank, R. R., and Palmquist, D. E. 1998. Nitrogen interactions with medusahead (Taeniatherum caput-medusae ssp. asperum) seedbanks. Weed Sci 46:191195.Google Scholar
Young, S. A., Schrumpf, B., and Amberson, E. 2003. The AOSCA Native Plant Connection. http://www.aosca.org/aoscanativeplantbrochure.pdf. Accessed: March 27, 2008.Google Scholar
Young, S. L., Barney, J. N., Kyser, G. B., Jones, T. S., and DiTomaso, J. M. 2008. Comparing functional diversity and functional similarity to Centaurea solstitialis (yellow starthistle) for resistance to invasion. Restor. Ecol. In press.Google Scholar
Young, S. L. and Claassen, V. P. 2008. Release of roadside native perennial grasses following removal of yellow starthistle (Centaurea solstitialis). Restor. Ecol. In press.Google Scholar
Zink, T. A. and Allen, M. F. 1998. The effects of organic amendments on the restoration of a disturbed coastal sage scrub habitat. Restor. Ecol 6:5258.Google Scholar
Zobel, M., van der Maarel, E., and Dupre, C. 1998. Species pool: the concept its determination and significance for community restoration. Appl. Veg. Sci 1:5556.Google Scholar