nutrient dynamics; sedimentation; hydrologic regimes; light availability Interferes with wetland functions, including productivity and nutrient cycling; Leaves rapid decay rate results in release of significant amounts of NH4+ and PO43-; Dramatic changes in the physical as well as the trophic structure of wetland habitat; Leads to altered wetland function, chemistry and function; inpedes natural water flow causing increased silt deposition and reduction in water quality; decreases storage capacities of impounded waterbodies; solid stands block out 100% light from underneath canopy.

Emery , S.L. and J.A. Perry, 1996. Decomposition rates and phosphorus concentration of purple loosestrife and cattail in 14 Minnesota wetlands. Hydrobiologia 323(2):129-138; Thompson, D.Q., R.L. Stuckey, and E.B. Thompson, 1987. Spread, impact, and control of purple loosestrife in North American Wetlands. Fish and Wildlife No. 2 U.S. Dept. Interior, Fish and Wildlife Service, Washington, D.C. 55pp. Malecki, R.A., B. Blossey, S.D. Hight, D. Schroeder, L.T. Kok, and J.R. Coulson, 1993. Biological control of purple loosestrife. Bioscience 43(10):680-85.

reduction and impact to nesting and foraging sites; cover for native animals; threatening to existing native wildlife and waterfoul species The rapid decay rateof purple loosestrife leaves has been shown to supply detritus to the ecosystem in the Autumn, whereas a much slower decay rate of resident vegetation supplies detritus throughout the winter and early spring- affecting juvenile salmon food webs; submersed terrestrial vegetation provides habitat for spawning and zooplankton critical to early fish survival- this is crowded-out by the establishment of loosestrife; dramatic changes in the trophic structure of wetland habitat has threatened the following wildlife species: Canada goose, wood duck, mallard, terns, canvasback, and sandhill cranes across the U.S.

Coddington, J. and K.G. Field, 1987. Rare and Endangered vascular plant species in Massachusetts. New England Botanical Club, Cambridge, Massachussetts. Malecki, R.A., B. Blossey, S.D. Hight, D. Schroeder, L.T. Kok, and J.R. Coulson, 1993. Biological control of purple loosestrife. Bioscience 43(10):680-85. Skinner, L.C., Rendall, W.J., and Fuge, E.L., 1994. Minnesota's purple loosestrife program: history, findings, and management recommendations. Minn. Dept. Nat. Res. Special Publ. 145:1-27.

anthropogenic disturbances such as: gardening near waterways, altering hydrology/irrigation, roads and trails, construction spread purple loosestrife; natural disturbance such as: flooding and native animal activities (birds flying to distant locations away from a source) spread purple loosestrife. Purple loosestrife usually needs some disturbance (anthropogenic or natural) to invade an area, to a lesser extent it can invade "intact" plant communites.

Thompson, D.Q., R.L. Stuckey, and E.B. Thompson, 1987. Spread, impact, and control of purple loosestrife in North American Wetlands. Fish and Wildlife No. 2 U.S. Dept. Interior, Fish and Wildlife Service, Washington, D.C. 55pp.;

Increasing, but less rapidly. Statewide, purple loosestrife has yet to invade many areas; in areas where purple loosestrife exists in California, the rate of spread has been gradual and steady.

California Department of Food and Agriculture Purple Loosestrife Program documents, reports, grant proposals, and mapping documentation.

numerous opportunities to spread via human-caused dispersal Brand new infestations likely to be from a gardener who planted loosestrife near a flowing water or pond situation; purple loosestrife can still be found for sale in nurseries (it is pulled off the shelf when found by county ag Dep't's) and can also be purchased on the internet; spreads along drainage/canal systems; can be transported on boats and in soil moved from site to site; BUT primary mode is through gardening/nursery

Mullin, B H., 1998. The Biology and of Purple Loosestrife (Lythrum salicaria). Weed Technology, vol. 12:397-401; personal observation; ancedotal; personal observation; ancedotal

see rationale purple loosestrife invades marshes, bogs, seeps, and reservoirs in many eastern and lakes states; purple loosestrife has yet to exploit these habitats in California; the range of purple loosestrife in the U.S. has greatly expanded since 1941, colonization of northern midwest in nearly complete; the most dramatic expansion, however, has been in the arid West, including staes of California, Idaho, Washington, Montana, and Wyoming.

Thompson, D.Q., R.L. Stuckey, and E.B. Thompson, 1987. Spread, impact, and control of purple loosestrife in North American Wetlands. Fish and Wildlife No. 2 U.S. Dept. Interior, Fish and Wildlife Service, Washington, D.C. 55pp.; Missouri Vegetation Management Manual, Tim Smith, Natural History Division;

California Department of Food and Agriculture Purple Loosestrife Program documents, reports, grant proposals, and mapping documentation; personal observation; ancedotal

see rationale In a limited manner, purple loosestrife has invaded the following ecological types in California: lakes (Shasta and Butte counties), ponds (Nevada and Placer counties), rivers/steams (Delta, Fresno County), canals (Shasta and San Joaquin counties), meadows (sections along Delta, Kern County, etc.)
Statewide in California, purple loosestrife has not reached near it's suspected capacity in total available habitat types (freshwater, estuarine: lakes, ponds, reservoirs, rivers, streams, canals); To a much lesser extent: meadows; marsh, riparian forest, woodland, and not yet in limited bog/seep types (while not as prevalent in California as back East and in Lake states).

California Department of Food and Agriculture Purple Loosestrife Program documents, reports, grant proposals, and mapping documentation; personal observation; ancedotal