Adkison, G. P. & Jackson, M. T. 1996. Changes in ground-layer vegetation near trails in midwestern U.S. forests. Nat. Areas. J 16: 14–23.
Alexander, F. 1946. The rate of passage of food residues through the digestive tract of the horse. J. Comp. Pathol. 56: 266–268.
Anonymous 1972. Trail of tears state forest. Illinois Department of Conservation, Springfield, Illinois. Site Brochure
Bartos, D. L., Brown, J. K. & Booth, G. D. 1994. Twelve years biomass response in aspen communities following fire. J. Range Manag. 47: 79–83.
Bates, G. H. 1935. The vegetation of footpaths, sidewalks, carttracks, and gateways. J. Ecol. 23: 463–487.
Benninger, M. C. 1989. Trail as conduits of movement for plant species in coniferous forests of Rocky Mountain National Park, Colorado. M.S. Thesis, Miami University
Benninger-Truax, M. C., Vankat, J. L. & Schaefer, R. L. 1992. Trail corridors as habitat and conduits for movement of plant species in Rocky Mountain National Park, Colorado, USA. Landsc Ecol. 6: 269–278.
Binggeli, P. 1996. A taxonomic, biogeographical and ecological overview of invasive woody plants. J. Veg. Sci. 7: 121–124.
Blackorby, C. 1994.a. IFOR and horsemen fight to keep trails open in Shawnee National Forest. Illinois Federation of Outdoor Recreation Newsletter.
Blackorby, C. 1994.b. Shawnee update. Illinois Federation of Outdoor Research Newsletter.
Braithewaite, R. W., Lonsdale, W. M. & Estbergs, J. A. 1989. Alien vegetation and native biota in tropical Australia: the impact of Mimosa pigra. Biol. Cons. 48: 189–210.
Brunner, H., Harris, R. V. & Amor, R. L. 1976. A note on the dispersal of blackberry Rubus procerus P. J. Muell. by foxes and emus. Weed Res. 16: 171–173.
Bratton, S. 1982. The effects of exotic plant and animal species on nature preserves. Nat. Areas J. 2: 3–13.
Burde, J. H. & Renfro, J. R. 1986. Use impacts on the Appalachian Trail. Proceedings, National Wilderness Research Conference: Current Research. Pp. 138–143. USDA Forest Service, General Technical Report INT-212. Ogden, Utah.
Coblentz, B. E. 1990. Exotic organisms: a dilemma for conservation biology. Cons. Biol. 4: 261–265.
Cole, D. 1978. Estimating the susceptibility of wildland vegetation to trailside alteration. J. Appl. Ecol. 15: 281–286.
Cole, D. 1993. Minimizing conflict between recreation and nature conservation. Pp. 105–122. In: Smith, D. S. & Hellmund, P C. (eds), Ecology of greenways. University of Minnesota Press, Minneapolis, Minneapolis.
Collins, S. L. & Gibson, D. J. 1990. Effects of fire on community structure in tallgrass and mixed-grass prairie. Pp. 81–98. In: Collins S.L. & Wallace, L.L. (eds), Fire in North American tallgrass prairies. University of Oklahoma Press, Norman, Oklahoma.
Dale, D. & Weaver, T. 1974. Trampling effects on vegetation of the trail corridors of North Rocky Mountain forests. J. Appl. Ecol. 11: 767–772.
Davis, M. A., Grime, J. P. & Thompson, K. 2000. Fluctuating resource in plant communities: a general theory of invasibility. J Ecol. 88: 258–534.
Elton, C. S. 1958. The ecology of invasions by animals and plants. Methuen, London, UK.
Evans, M. 1981. The vascular flora of Trail of Tears State Forest, Union County, Illinois. M.S. thesis, Southern Illinois University at Carbondale
Faulkner, J. 1993. Damage to natural areas purchased with LAWCON funds. Illinois Nature Preserves Commission.
Fenner, M. 1985. Seed ecology. Chapman & Hall, London.
Gonzalez-Espinoza, M. & Quintana-Ascencio, P. F. 1986. Seed predation and dispersal in a dominant plant: Opuntia, ants, birds, and mammals. Pp. 273–284. In: Estrada, A. & Flemming, T H. (eds), Frugivores and seed dispersal. Dr. W. Junk Publishers, Dordrecht.
Gotelli, N. J. & Graves, G. R. 1996. Null models in ecology. Smithsonian Institute Press, Washington D. C.
Griffith, D. & Lacey, J. R. 1991. Economic evaluation of spotted knapweed Centaurea maculosa. control using picloram. J. Range Manag. 44: 43–47.
Hall, C. N. & Kuss, F. R. 1989. Vegetation alteration along trails in Shenandoah National Park, Virginia. Biol. Cons. 48: 211–227.
Hammit, W. E. & Cole, D. N. 1987. Wildland recreation: Ecology and management. John Wiley & Sons, New York.
Harmon, G. W. & F. D. 1934. The percentage and viability of weed seeds recovered in the feces of farm animals and their longevity when buried in manure. J. Am. Soc. Agron. 26: 762–767.
Harper, J. L. 1977. Population biology of plants. Academic Press, London.
Heady, H. F. 1954. Viable seed recovered from fecal pellets of sheep and deer. J. Range Manag. 7: 259–261.
Hester, E. F. 1991. The U.S. National Park Service experience with exotic species. Nat. Areas J. 11: 127–128.
Hill, M. O. DECORANA — a FORTRAN Program for detrended correspondence analysis and reciprocal averaging. Ecology and Systematics., Cornell University, Ithaca, New York.
Hill, M. O. & Gauch, H. G. 1980. Detrended correspondence analysis: an improved ordination technique. Vegetatio. 42: 47–58.
Hobbs, R. J. & Huenneke, L. F. 1992. Disturbance, diversity, and invasion: implications for conservation. Cons. Biol. 6: 324–337.
Holland, P. & Olson, S. 1989. Introduced versus native plants in Austral forests. Prog. Phys. Geog. 13: 260–293.
Janzen, D. H. 1981. Enterlobium cyclocarpun seed passage rate and survival in horses, Costa Rican pleistocene seed dispersal agents. Ecology. 62: 593–601.
Janzen, D. H. 1982. Differential seed survival and passage rates in cows and horses. Oikos. 38: 150–156.
Kowarik, I. 1995. Time lags in biological invasions with regard to the success and failure of alien species. Pp. 15–38. In: Pysek, P., Prach, K., Rejmanek, M. & Wade, M. (eds), Plant invasions — general aspects and special problems. SPB Academic Publishing, Amsterdam, The Netherlands.
Kucera, C. L. & Koelling, M. 1964. The influence of fire on composition of central Missouri prairie. Am. Midland Nat. 72: 142–147.
Land, F. 1994. Troubled trails. Western Horseman., April, 6–97.
Leighton, M., Ekblaw, G. E. & Hamberg, L. 1948. Physiographic divisions of Illinois. Geology. 56: 16–33.
Liddle, M. J. 1975. A selective review of the ecological effects of human trampling on natural ecosystems. Biol. Cons. 7: 17–36.
Ludwig, J. A. & Reynolds, J. F. 1988. Statistical ecology: A primer on methods and computing. John Wiley & Sons, New York.
Malo, J. E. & Suarez, F. 1998. The dispersal of a dry-fruited shrub by red deer in a Mediterranean ecosystem. Ecography. 21: 204–211.
McCully, W. G. 1951. Recovery and viability of Macartney rose seeds fed to cattle. J. Range Manag. 4: 101–106.
Meekins, J. F. & McCarthy, B. C. 199. Competitive ability of Allaria petiolata (Garlic Mustard, Brassicaceae), an invasive, nonindigenous forest herb. Int. J. Plant Sci. 160: 743–752.
Middleton, B. A. & Mason, D. H. 1992. Seed herbivory by nilgai, feral cattle, and wild boar in the Keolado National Park, India. Biotropica. 24: 538–543.
Mohlenbrock, R. H. 1986. Guide to the vascular flora of Illinois Southern Illinois. University Press, Carbondale, Illinois.
Mooney, H. A. & Drake, J. 1986. The ecology of biological invasions of North America and Hawaii. Springer-Verlag, New York.
Noss, R. F. 1990. Can we maintain biological and ecological integrity?. Cons. Biol. 4: 241–243.
Ohmann, L. F. & Grigal, D. F. 1981. Contrasting vegetation responses following two forest fires in northeastern Minnesota. Am. Midland Nat. 106: 54–64.
Pickett, S. T. A. & White, P. S. 1985. The ecology of natural disturbance and patch dynamics. Academic Press, Orlando, Florida.
Piggin, C. M. 1978. Dispersal of Echium plantagineum L. by sheep. Weed Res. 18: 155–160.
Ridley, H. N. 1930. Dispersal of plant throughout the world. Reeve, Aston, Kent, UK.
Scheiner, S. M., Sharik, T. L., Roberts, M. R. & Kopple, R. V 1988. Tree density modes of tree recruitment in a Michigan pinehardwood forest after clear-cutting and burning. Can. Field-Nat. 102: 634–638.
Schwegman, J. E., Fell, G. D., Hutchinson, M. D., Paulson, G., Shepherd, W. M. & White, J. 1973. Comprehensive plant for the Illinois Preserves system. Part II — The Natural Divisions of Illinois. Illinois Nature Preserves Commission, Springfield, Illinois.
Shawnee National Forest. 1992. Shawnee Nation Forest Amended Land and Resource Management Plant Alternative 5 — Final Supplemental Environmental Impact Statement. USDA, Forest Service Eastern Region.
Shimp, J. 1996. Vegetation analysis and vascular floras of three Research Natural Areas RNAs. in the Shawnee Nation Forest: Barker Bluff, Dennison Hollow, and Panther Hollow in southeastern Illinois. M.S. Thesis, Southern Illinois University at Carbondale
Simberloff, D. 1978. Use of rarefraction and related methods in ecology. pp. 150–165. In: Dickson, K. L., Cairns, J. and Livingston, R. J. (eds), Biological data in water pollution assessment: quantitative and statistical analyses, ASTM STP 652. American Society for Testing and Materials
Simberloff, D. 1979. Rarefraction as a distribution-free method of expressing and estimating diversity. Pp. 159–176. Grassie, J. F., Pall, G. P., Smith, W. & Taillie, C. (eds), Ecological diversity in theory and practice. International Co-operative Publishing House, Fairland, Maryland.
Smith, R. G. 1988. The vascular flora of Jackson Hollow. M.S thesis, Southern Illinois University at Carbondale.
Soule, M.E. 1990. The onslaught of alien species, and other challenges in the coming decades. Cons. Biol. 4: 233–239.
Stritch, L. R. 1982. A floristic survey of the Hayes Creek Canyon watershed, Pope County, Illinois. M.S. thesis, Southern Illinois University at Carbondale.
United States Congress, Office of Technology Assessment 1993. Harmful non-indigenous species in the United States OTA-F-565. United States Government Printing Office, Washington, D.C.
Vander Noot, G. W., Symons, L. D., Lydman, R. K. & Fonnesbeck, P. V. 1967. Rate of passage of various feedstuffs through the digestive tract of horses. J. Animal Sci. 26: 1309–1311.
Vitousek, P. M. 1988. Diversity and biological invasions of oceanic islands. Pp. 181–189. In: Wilson, E. O. and Peters, F. M. (eds), Biodiversity. National Academic Press, Washington, D. C.
Weaver, T. & Dale, D. 1978. Trampling effects of hikers, motorcycles, and horses in meadows and forests. J. Appl. Ecol. 15: 451–457.
Welch, D. 1985. Studies in the grazing of heather moorland in northeast Scotland; IV. Seed dispersal and plant establishment in dung. J. Appl. Ecol. 22: 461–472.
Westman, W. E. 1990. Park management of exotic plant species: problems and issues. Cons. Biol. 4: 251–259.
Williamson, M. 1996. Biological invasions. Chapman & Hall London, England.
Wilson, J. P. & Seney, J. P. 1994. Erosional impact of hikers, horses, motorcycles, and off-road bicycles on mountain trials in Montana. Mountain Res. Devel. 14: 77–88.
Zar, J. H. 1998. Biostatistical analysis. Prentice Hall. New Jersey.