Invasive Plants

Invasive wetland plants and native biota
Aquatic pest plants are an international concern due to their interference with biodiversity conservation, fisheries, transportation, water supply, irrigation, recreation, and disease vector management. We are studying four species of concern to conservationists and restorationists in the U.S.: purple loosestrife (Kiviat 1989, 1995, 1996; Barbour & Kiviat 1997; Krause et al. 1997; Kiviat 1999), common reed (Kiviat 1987a, 1994c, Krause et al. 1997, Winogrond & Kiviat 1997, Meyerson et al. 2000, Kiviat & Hamilton 2001), water-chestnut (Kiviat 1987b, 1993b, K. Schmidt 1986, Anderson & Schmidt 1989, Pelczarski & Schmidt 1991, Sidari & Schmidt 1990, Hummel unpublished data), and tree-of-heaven (Ailanthus) (Kiviat, submitted b). Loosestrife, water-chestnut, and tree-of-heaven are introduced species, and reed is partly native but also invasive. Our research emphasizes the ecological relationships of invading species with native plants and animals, as well as the influences of the dominant plants on ecosystem processes. Work to date has covered a variety of animals, and we have recently completed two review papers on higher vertebrates (Kiviat et al., submitted a, b). We are also interested in past, present, and future human uses of invasive plants (see Kiviat & Hamilton 2001). A forthcoming major review of invasive plants in the New York City region, focusing on purple loosestrife and common reed (Kiviat, submitted a), and a synthesis of information on the Hackensack Meadowlands (New Jersey), which addresses many aspects of common reed ecology and management (Kiviat & MacDonald, 2002), integrate natural history, ecology, and innovative approaches to management of invasive plants. In 2002 we will begin a study of another invasive plant, Japanese knotweed, in relation to public water supply.

Invasive Introduced or Overabundant Native Animals
Both native and introduced animal species can have impacts that interfere with human use of resources and management of the environment. Some species that are recently introduced have not reached population levels that cause impacts, or the impacts have not been studied yet. Once such recently introduced species is the Chinese mitten crab, which was first noticed in the Hudson River in 2007. In 2008, Bob Schmidt discovered a substantial population in the lower Saw Kill at Bard College, and subsequently found mitten crabs in other tributaries of the freshwater-tidal Hudson River. Bob is conducting surveys to document the spread of this species. The mitten crab spends much of its life in fresh water where it may be capable of damaging stream banks by burrowing.

We have also conducted research on a native mammal, the common muskrat, that fluctuates in numbers and is sometimes considered a pest where it burrows through dikes or dams, depredates crops, or damages desirable marsh vegetation. The muskrat, however, has an important influence on its marsh ecosystem by selective feeding on plants, digging burrows, and building mounds of plant and soil material for winter lodges. These activities provide resources such as nesting and basking sites for other animals, alter vegetation patterns, and affect nitrogen processing in the soil (Kiviat 1978, 1994, Connors et al. 2000).

Economic Botany
Invasive plants considered weeds in one part of the world are often valued for food, medicine, fiber, and other uses in another region. Human uses of many invasive marsh plants, and many other common wetland plants, have not been well documented. We have compiled a Native American ethnobotany of common reed (Phragmites) (Kiviat & Hamilton 2001), which is well-known as a resource species in the Old World but for which there was no synthetic ethnobotanical study in North America. A thorough understanding of potential resource values of plants such as common reed and water-chestnut (Trapa) will help identify harvesting alternatives for natural and constructed wetlands where these plants abound. These studies will also elucidate aspects of wetland ecology that have influenced human populations in the U.S. and Europe. We are particularly interested in approaches to common reed management that incorporate harvest of reed for products.

References:

Anderson, A.B. & R.E. Schmidt. 1989. Survey of larval and juvenile fish populations in water-chestnut (Trapa natans) beds in Tivoli South Bay, a Hudson River tidal marsh. P. VI-1 to VI-34 in E.A. Blair and J.R. Waldman, eds. Polgar Fellowship Reports of the Hudson River National Estuarine Research Reserve Program, 1988. Hudson River Foundation, New York, NY.

Barbour, J.G. & E. Kiviat. 1997. Introduced purple loosestrife as host of native Saturniidae (Lepidoptera). Great Lakes Entomologist 30(3):115-122.

Kiviat, E. 1987a. Common reed (Phragmites australis). P. 22-30 in D. Decker & J. Enck eds. Exotic Plants with Identified Detrimental Impacts on Wildlife Habitats in New York State. New York Chapter, Wildlife Society.

Kiviat, E. 1987b. Water chestnut (Trapa natans). P. 31-38 in D. Decker & J. Enck, eds. Exotic Plants with Identified Detrimental Impacts on Wildlife Habitats in New York State. New York Chapter, Wildlife Society.

Kiviat, E. 1989. Purple loosestrife’s tangled locks. News from Hudsonia (September):1-6.

Kiviat, E. 1993. Under the spreading water-chestnut. News from Hudsonia 9(1):1-6.

Kiviat, E. 1994. Reed, sometimes a weed. News from Hudsonia 10(3):4-6.

Kiviat, E. 1995. Tangled locks: The purple loosestrife invasion and biological diversity. Annandale 134(5):34-39.

Kiviat, E. 1996. American goldfinch nests in purple loosestrife. Wilson Bulletin 108(1):182-186.

Kiviat, E. 1999. Loosestrife: Purple peril or purple prose? News from Hudsonia 14(2):1-3.

Kiviat, E. Submitted a. Invasive wetland plants and wildlife in the New York City region. Wildlife Conservation Society Working Papers, Bronx, New York.

Kiviat, E. Submitted b. Occurrence of Ailanthus altissima on a Maryland tidal estuary. Castanea.

Kiviat, E. & E. Hamilton. 2001. Phragmites use by Native North Americans. Aquatic Botany 69(2-4):341-357.

Kiviat, E. & K. MacDonald. 2002. Hackensack Meadowlands, New Jersey, biodiversity: A review and synthesis. Hackensack Meadowlands partnership.

Kiviat, E., C. Winters & F. Baumgarten. Submitted b. Use of Phragmites australis by breeding birds in North America. Environmental Management.

Krause, L.H., C. Rietsma & E. Kiviat. 1997. Terrestrial insects associated with Phragmites australis, Typha angustifolia, and Lythrum salicaria in a Hudson River tidal marsh. P. V-1 to V-35 in W.C. Nieder & J.R. Waldman, eds. Final Reports of the Tibor T. Polgar Fellowship Program 1996. Hudson River Foundation and New York State Department of Environmental Conservation – Hudson River National Estuarine Research Reserve.

Meyerson, L.A., K. Saltonstall, L. Windham, E. Kiviat & S.E.G. Findlay. 2000. A comparison of Phragmites australis in freshwater and brackish marsh environments in North America. Wetlands Ecology and Management 8(2-3):89-103.

Pelczarski, K. & R.E. Schmidt. 1991. Evaluation of a pop net for sampling fishes from water-chestnut beds in the tidal Hudson River. P. V-1 to V-33 in E.A. Blair and J.R. Waldman, eds. Final Reports of the Tibor T. Polgar Fellowship Program 1990. Hudson River Foundation, New York, NY.

Schmidt, K.A. 1986. The life history of the chrysomelid beetle Pyrrhalta nymphaeae (Galerucinae) on water chestnut, Trapa natans (Hydrocaryaceae), in Tivoli South Bay, Hudson River, NY. P. V-1 to V-38 in J.C. Cooper, ed. Fellowship Reports of the Hudson River National Estuarine Sanctuary Program, 1985. Hudson River Foundation, New York, NY.

Sidari, M. & R.E. Schmidt. 1990. Larval fish foods in water-chestnut beds. P. VI-1 to VI-23 in Final Reports of the Tibor T. Polgar Fellowship Program 1989. Hudson River Foundation and New York State Department of Environmental Conservation – Hudson River National Estuarine Research Reserve.

Winogrond, H.G. & E. Kiviat. 1997. Invasion of Phragmites australis in the tidal marshes of the Hudson River. P. VI-1 to VI-29 n W.C. Nieder & J.R. Waldman, eds. Final Reports of the Tibor T. Polgar Fellowship Program 1996. Hudson River Foundation and New York State Department of Environmental Conservation – Hudson River National Estuarine Research Reserve.

Hudsonia, a tax-exempt not-for-profit corporation of the State of New York, classified 501(c)(3) by the Internal Revenue Service, relies on the generous, tax-deductible contributions from members of our community to sustain our research and education. We appreciate your support of our work.

Donate