Invasive Plant Impacts. Chapter 1 in CIPM Online Invasive Plant Management Textbook

Chapter 1. Invasive Plant Impacts

Susan Kelly, Montana State University

Resources | References

Ecological and Economic Impacts

The impacts of invasive species are felt from the local to the global scale. Scientists, land managers, and the general public are becoming more aware of invasive plant impacts. Weed invasion is considered the second most serious threat to natural habitats, after habitat fragmentation and loss (Randall 1996). The economies of many states are based upon use or extraction of natural resources for food and economic growth. Utilization of resources has been impacted by the encroachment of invasive plants. Selected studies have documented the impact of individual species. For example,

It is estimated that tansy ragwort invasion has caused losses of $6 million per year to the state of Oregon (Radtke and Davis 2000).
Hirsch and Leitch (1996) estimated a $42 million annual loss due to three Centaurea species in Montana, North Dakota, South Dakota.

As alarming as some of these numbers sound, comprehensive data about economic impacts are scarce, and it is even more daunting to assess economic and ecological costs for invasive plant species in a meaningful way. Cost benefit analysis reflecting the true costs associated with invasive plant invasion have been completed for few species at varying scales using different methodologies. The extent of economic damage caused by invasive species is only beginning to be appreciated by economists and policy makers, and the methods by which to do so are still being explored or have not been tested at the landscape scale.

Hybridization between native cordgrass, Spartina alterniflora, and an exotic cordgrass, Spartina folisa, have created a fast-growing plant with rhizomatous roots which accentuates tidal sediment buildup and has decreased habitat for shorebirds and waterfowl in the San Francisco Bay (Vila et al. 2000)
Melaleuca invades wetland areas in Florida and creates monospecific stands. Increased shade and soil temperature change the local microclimate, the water table is lower, and fire frequency and intensity are altered (Randall 1996).
A significant reduction in the five most common native species was recorded in native mixed grass prairie invaded with leafy spurge, Euphorbia esula (Belcher and Wilson 1989).
Invasive pathogens from Europe essentially eliminated the once dominant American chestnut and American elm trees (Mooney and Hobbs 2000)

Plant invasions have been shown to alter ecosystem processes such as nutrient cycling, fire frequency, hydrologic cycles, sediment deposition, and erosion. Invasive plants displace native species or hybridize with them, altering the gene pool. Yet, ecological impact is perhaps even more difficult to assess than the economic effect. Putting a price on ecosystem services, or those benefits supplied to human societies by natural ecosystems, is complex. Such benefits include timber, game animals, and pharmaceutical products, items that we have traditionally assigned an economic value, and can “price.” Ecosystem services, such as purification of air and water, climate regulation, regeneration of soil fertility, decomposition of wastes, and maintenance of biological diversity are more complex, and it becomes more difficult to assign value. The natural processes that occur within an ecosystem; e.g., the nitrogen cycle and the carbon cycle, are largely not accounted for when trying to assess the cost of ecological impact. How to assess the values as well as how to assign value to ecological assets is an issue that economists, ecologists, and policymakers are facing.

Resources

A. Belsky, J. A. and Gelbard, J. L. (2000). Livestock Grazing and Weed Invasions in the Arid West. Bend, Oregon Natural Desert Association: 1-30.

Auld, B. A., J. Hosking, et al. (1983). An analysis of the spread of tiger pear and parthenium weed in Australia. Australian Weeds 2: 56-60.

Auld, B. A., K. M. Menz, et al. (1979). Dynamics of weed spread: implications for policies of public control. Protection Ecology 1: 141-148.

Auld, B. A. and C. A. Tisdell (1986). Impact Assessment of Biological Invasions. Ecology of Biological Invasions. R. H. Groves and J. J. Burdon. Cambridge, Cambridge UP: 79-88.

Bangsund, D. A., Leistritz F.L., et al (1997). Predicted Future Economic Impacts of Biological Control of Leafy Spurge in the Upper Midwest. Fargo, Department of Agricultural Economics, North Dakota State University: 1-8.

Bangsund, D. A., and Nudell D., et al (2000). Economic analysis of controlling Leafy Spurge with Sheep. Fargo, Department of Agricultural Economics North Dakota State University: 1-19.

Bangsund, D. A., F. L. Leistritz, et al. (1999). Assessing economic impacts of biological control of weeds: the case of leafy spurge in the northern Great Plains of the United States. Environmental Management 56: 35-43.

Bangsund, D. A., J. A. Leitch, et al. (1996). Economics of herbicide control of leafy spurge. Agricultural and Resource Economics 21(2): 381-395.

Belnap, J. and S. L. Phillips. (2001) Soil biota in an ungrazed grassland: response to annual grass (Bromus tectorum) invasion. Ecological Applications. 11(5) 1261-1275

Byers, J. E. and L. Goldwasser (2001). Exposing the mechanism and timing of impact of nonindigenous species on native species. Ecology 82(5): 1330-1343.

Callaway, R. M. and E. T. Aschehoug (2000). Invasive plants versus their new and old neighbors: A mechanism for exotic invasion. Science. 290: 521-523.

Carlton, J. T. (1996). Biological invasions and cryptogenic species. Ecology 77(6): 1653-1655.

Cheater, M. (1992). Alien Invasion. The Nature Conservancy: 25-29.

Crawley, M. J. (1986). The population biology of invaders. Phil Trans. R. Soc. Lond. B 314: 711-731.

Daehler, C. C. and D. R. Strong (1996). Status, prediction and prevention of introduced cordgrass Spartina spp. invasions in pacific estuaries, USA. Biological Conservation 78: 51-58.

D'Antonio, C. M. (2000). Fire, Plant Invasions, and Global Changes. Invasive Species in a Changing World. H. A. Mooney, Hobbs, R.J. Washington D.C., Island Press: 65-93.

D'Antonio, C. M., H. R. Hughes, et al. (1998). The response of native species to removal of invasive exotic grasses in a seasonally dry Hawaiian woodland. Journal of Vegetation Science 9: 699-712.

D'Antonio, C. M. and P. M. Vitousek (1992). Biological invasions by exotic grasses, the grass-fire cycle, and global change. Ann. Rev. Ecol. Syst. 23: 63-87.

DiTomaso, J.M. (2000). Invasive weeds in rangelands: Species, impacts, and management. Weed Science 48: 255-265.

DeWit, M. (2001). Economic Impacts of Invasive Weeds. Noxious Times. Sacramento: 8-11.

Ehrenfeld, J. G., P. Kourtev, et al. (2001). Changes in soil functions following invasions of exotic understory plants in deciduous forests. Ecological Applications 11(5): 1287-1300.

Ehrenfeld, J. G. and N. A. Scott (2001). Invasive Species and the Soil: Effects on Organisms and Ecosystem Processes. Ecological Applications 11(5): 1259-1260.

Evans, R. D., R. Rimer, et al. (2001). Exotic plant invasion alters nitrogen dynamics in an arid grassland. Ecological Applications 11(5): 1301-1310.

Fox, M. D. and B. J. Fox (1986). The Susceptibility of Natural Communities to Invasion. Ecology of Biological Invasions. R. H. Groves and J. J. Burdon. Cambridge, Cambridge UP: 57-66.

Fuhlendorf, S. D. and D. M. Engle (2001). Restoring heterogeneity on rangelands: ecosystem management based on evolutionary grazing patterns. BioScience 15(8): 625-632.

Groves, R. H. (1986). Plant invasions of Australia: an overview. Ecology of Biological Invasions. R. H. Groves and J. J. Burdon. Cambridge, Cambridge UP: 137-149.

Haber, E (1996) Impact of Invasive Plants on Species and Habitats at Risk in Canada. Canadian Wildlife Service and National Botanical Services, Ottawa.

Hengeveld, R. Modeling the Impact of Biological Invasions. Invasive Species and Biodiversity Management. O. T. Sandlund, P. J. Schei and A. Viken. Boston, Kluwer Academic Publishers. 24: 127-138.

Higgins, S. I., E. J. Azorin, et al. (1997). A dynamic ecological-economic model as a tool for conflict resolution in an invasive alien-plant, biological control and native-plant scenario. Ecological Economics 22(2): 141-154.

Higgins, S. I., J. K. Turpie, et al. (1997). An ecological economic simulation model of mountain Fynbos ecosystems: dynamics, valuation and management. Ecological Economics 22(2): 155-169.

Huber, D. M., M. E. Hugh-Jones, et al. (2002). Invasive Pest Species: Impacts on Agricultural Production, Natural Resources, and the Environment. Ames, Council for Agricultural Science and Technology: 1-18.

Hughes, F. P., P. M. Vitousek, et al. (1991). Alien grass invasion and fire in the seasonal submontane zone of Hawaii. Ecology 72: 743-746.

James, D. (1995). The threat of exotic grasses to the biodiversity of semiarid ecosystems. Arid Lands Newsletter: 1-4.

Larson, D. L., P. J. Anderson, et al. (2001). Alien plant invasion in mixed-grass prairie: Effects of vegetation type and anthropogenic disturbance. Ecological Applications 11(1): 128-141.

Leitch, J. A., F. L. Leistritz, et al. (1996). Economic effect of leafy spurge in the upper great plains: Methods, models, and results. Impact Assessment 14: 419-432.

Lesica, P. and F. W. Allendorf (1999). Ecological genetics and the restoration of plant communities: mix or match? Restoration Ecology 7(1): 42-50.

Levine, J. M. and C. M. D'Antonio (1999). Elton revisited: a review of evidence linking diversity and invasibility. Oikos 87: 15-26.

Lewis, M. A. (2000). Spread rate for a nonlinear stochastic invasion. Mathematical Biology 41: 430-454.

Lewis, M. A. and S. Pacala (2000). Modeling and analysis of stochastic invasion processes. Mathematical Biology 41: 387-429.

Lonsdale, W. M. (1999). Global Patterns of Plant Invasions and the Concept of Invasibility. Ecology 80(5): 1522-1536.

Luken, J. O. and J. W. Thieret (1997). Assessment and Management of Plant Invasions. New York, Springer-Verlag.

M. Vila, E. W., C.M. D'Antonio (2000). Conservation Implications of Invasion by Plant Hybridization. Biological Invasions 2: 207-217.

Mack, M. C., S. D., et al. (2000). Biotic Invasion: Causes, Epidemiology, Global Consequences and Control. Issues in Ecology 5: 1-19.

Mack, M. C. and C. M. D'Antonio (1998). Impacts of biological invasions on disturbance regimes. Tree 13(5): 195-198.

Mack, M. C., C. M. D'Antonio, et al. (2001). Alteration of ecosystem nitrogen dynamics by exotic plants: A case study of C4 grasses in Hawaii. Ecological Applications 11(5): 1323-1335.

Meekins, J.F. and B.C. McCarthy (2001). Effect of environmental variation on the invasive success of a nonindigenous forest herb. Ecological Applications 11(5): 1336-1348..

Morghan, K. J. R. and T. R. Seastedt (1999). Effects of soil nitrogen reduction on nonnative plants in restored grasslands. Restoration Ecology 7(1): 51-55.

Naylor, R. L. (2000). The Economics of Alien Species Invasions. Invasive Species in a Changing World. H. A. Mooney and R. J. Hobbs. Washington D.C., Island Press: 241-259.

Newsome, A. E. and I. R. Noble (1986). Ecological and Physiological Characters of Invading Species. Ecology of Biological Invasions. R. H. Groves and J. J. Burdon. Cambridge, Cambridge UP: 1-20.

Parker, I. M. and P. M. Kareiva (1996). Assessing the risks of invasion for genetically engineered plants: acceptable evidence and reasonable doubt. Biological Conservation 78: 193-203.

Parker, I. M., Simberloff D., et al. (1999). Impact: toward a framework for understanding the ecological effects of invaders. Biological Invasions 1: 3-19.

Perrings, C., M. Williamson, et al. (2000). The Economics of Biological Invasions. Cheltenham, UK, Edward Elgar.

Pimentel, D., L. Lach, et al. (2000). Environmental and economic costs of nonindigenous species in the United States. BioScience 50(1): 53-65.

Redente, E. F., J. E. Friedlander, et al. (1992). Response of early and late semiarid seral species to nitrogen and phosphorus gradients. Plant and Soil 140: 127-135.

Schmitz, D. C., and Simberloff, D. (1997). Biological Invasions: A Growing Threat. Issues in Science and Technology: 1-12.

Schoennagel, T. L. and D. M. Waller (1999). Understory responses to fire and artificial seeding in an eastern Cascades Abies gradis forest, U.S.A. Can. J. For. Res. 29: 1393-1401.

Scott, N. A., S. Saggar, et al. (2001). Biogeochemical impact of hieracium invasion in New Zealand's grazed tussock grasslands: sustainability implications. Ecological Applications 11(5): 1311-1322.

Simberloff D. and VonHolle, D. (1999). Positive interactions of nonindigenous species: invasional meltdown? Biological Invasions 1: 21-32.

Smith, M. D. and A. K. Knapp (2001). Size of the local species pool determines invasibility of a C4 dominated grassland. Oikos 92: 55-61.

Starfinger, S., K. Edwards, et al. (1998). Plant Invasions: Ecological Mechanisms and Human Responses. Leiden, Backhuys.

Strohlgren, T. J., L. D. Schell, et al. (1999). How grazing and soil quality affect native and exotic plant diversity in Rocky Mountain grasslands. Ecological Applications 9(1): 45-64.

Swincer, D. E. (1986). Physical characteristics of sites in relation to invasions. Ecology of Biological Invasions. R. H. Groves and J. J. Burdon. Cambridge, Cambridge UP: 67-76.

Symstad, A. J. (2000). A test of the effects of functional group richness and composition on grassland invasibility. Ecology 81(1): 99-109.

Tilman, D. (1999). The ecological consequences of changes in biodiversity: A search for general principles. Ecology 80(5): 1455-1474.

Vitousek, P. M., D'Antonio, C.M., Loope, L.L. Westbrooks, R. (1996). Biological Invasions as Global Environmental Change. American Scientist 84: 468-478.

Weber, E. (1998). The dynamics of plant invasions: a case study of three exotic goldenrod species (Solidago L.) in Europe. Journal of Biogeography 25: 147-154.

Williamson, M. (1998). Measuring the impact of plant invaders in Britain. Plant Invasions: Ecological Mechanisms and Human Responses. U. Starfinger, K. Edwards, I. Kowarik and M. Williamson. Leiden, Backhuys Publishers.

Zavaleta, E. (2000). Valuing Ecosystems Services Lost to Tamarix Invasion in the United States. Invasive Species in a Changing World. H. A. Mooney, Hobbs, R.J. Washington D.C., Island Press: 261-300.

Zavaleta, E. S., R. J. Hobbs, et al. (2001). Viewing invasive species removal in a whole-ecosystem context. Trends in Ecology and Evolution 16(8): 454-459.

References

Belcher, J.W. and S.D. Wilson. 1989. Leafy spurge and the species composition of a mixed-grass prairie. J. Range Management 42:172-175.

Belsky, J. A. and Gelbard, J. L. (2000). Livestock Grazing and Weed Invasions in the Arid West. Bend, Oregon Natural Desert Association: 1-30.

Hirsch, S.A., and Jay A. Leitch. 1996. The Impact of Knapweed on Montana's Economy. Agricultural Economics Report No. 355, Agricultural Experiment Station, North Dakota State University, Fargo.

Mooney, H.A. and R.J. Hobbs. 2000. Invasive Species in a Changing World. Island Press.

Radtke H.D. and S.W. Davis. 2000. Economic Analysis of Containment Programs, Damages, and Production Losses from Noxious Weeds in Oregon. Oregon Department of Agriculture, Salem, OR.

Randall, J.M. 1996. Weed control for the preservation of biological diversity. Weed Technology 10:370-383.