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Water gardens


                                                                 U.S. Fish & Wildlife Service

                                                                Water Gardens and
                                                                Introduced Species

                    Introduction                                population that enters an aquatic
                    Constructing a water garden is a unique     ecosystem outside of its historical native

                                                                                                                                                           Noxious and Nuisance Plant Information System Version 3
                    and enjoyable way to accent a property.     range. These species may be plants or
                    There are many types of aquatic plants      animals and may arrive from different
                    and animals commonly used in water          countries or from different locations of
                    gardens including water lettuce, cattails   the same country. Non-native species like
                    and koi. Many of the popular species are    goldfish and purple loosestrife, are now
                    not native to the area or watershed in      prevalent in many regions across the U.S.
                    which they are being planted.               after first being used as ornamentals.
                                                                Once established, introduced species may
                    Introduced species are defined as any        cause ecological and economic problems
                    individual, group, subspecies or            and can be difficult if not impossible to
                                                                control or eradicate.
                    Water lettuce (Pistia stratiotes) is a
                    favorite among water gardeners because      Why should we be concerned?
                    of its hardiness and beauty. However, if    ■ Ecological Concerns
                    released, this plant can create a dense       The introduction of a new species into
                    floating mat, crowding native emergent         an ecosystem may affect native and         Water Hyacinth (Eichhoria crassipes),
                    species and shading submerged species.        endemic species. For example, many         native to South America, was discovered
                    In August 2000, U.S. Fish & Wildlife          fish species depend on areas of             by U.S. Fish and Wildlife Service staff in
                    staff discovered water lettuce in Bull        vegetation for cover, feeding, and         August 2001in the same creek where
                    Creek, a tributary to the Erie Canal in       spawning and can be affected by            water lettuce was found.
                    North Tonawanda, N.Y.
                                                                                                               changes in plant species composition
                                                                                                               and density. Native and migratory bird
                                                                                                               populations dependent on native plant
                                                                                                               communities for feeding, nesting and
                                                                                                               stopover can also be affected.

                                                                                                             ■ Economic Concerns
                                                                                                               The successful invasion and
                                                                                                               establishment of non-native aquatic
                                                                                                               plants and animals can result in local
                                                                                                               and regional economic losses. Habitat
                                                                                                               changes caused by invasive species can
                                                                                                               reduce revenues generated by nature-
                                                                                                               based tourism as destinations lose their
                                                                    attraction or become next to impossible
                                                                                                               to access. Industrial facilities, such as
                                                                                                               hydroelectric power companies, face
                                                                                                               the costly challenge of controlling
                                                                                                               invasive species to maintain operations.
                                                                                                               In addition, as plant densities increase,
                                                                                                               navigation, irrigation and flood control
USFWS/Mike Weimer

                                                                                                               can be affected.

                                                                                                             The newest potential vector advancing
                                                                                                             the spread of invasive aquatic plants is
                                                                                                             the Internet, where seeds and plants can
                                                                                                             be purchased from locations worldwide.
                                                                                                                                                  For more information:
                                                                                                                                                  U.S. Geological Survey

                                                                                                                                                  Aquatic Nuisance Species Task Force

                                                                                                                                                  U.S. Fish and Wildlife Service

                                                                                                                                                  Sea Grant Nonindigenous Species
 USFWS/Mike Sowinski

                                                                                                                                                  Reducing the Introduction and Damage
                                                                                                                                                  of Aquatic Nonindigenous Species

                                                                                                                                                  National Invasive Species Council
                             Japanese knotweed (Polygonum cuspidatum) was introduced into N. America as an
                             ornamental hedge and is now common along creeks.                                                                     U.S. Department of Agriculture
                             Such easy access emphasizes the need to                               ■   Dispose of cuttings and unwanted
                             educate consumers about the harmful                                       plants by freezing and then placing in
                             effects of invasive species as well as state                              household trash. (Plant materials
                             and federal laws prohibiting the                                          can also be burned where backyard

                                                                                                                                                                                            Aquatic Plant Information System Version 2
                             possession of certain species.                                            burning is legal.)

                             What can you do?                                                      ■   Never include cuttings or unwanted
                             Once an introduced species becomes                                        plants in compost. (Seeds can be
                             established, complete eradication is                                      tolerant of drying and freezing.)
                             often impossible. Preventing invasions
                             of aquatic plants by emphasizing the                                  ■   Never dump unwanted plants or
                             importance of informing water                                             plant materials into a waterbody.
                             gardeners, retailers, and greenhouse                                  ■   Create water gardens only in areas
                             operators about proper disposal                                           isolated from waterways to avoid
                             procedures and pathways of spread,                                        accidental release.
                             may be the most effective control
                             alternative. To minimize the risk of                                  ■   Use native plant species.              Water chestnuts (Trapa natans) are
                             introducing plant species:                                                                                       controlled by mechanical harvesting in many
                                                                                                   ■   Report any releases to a local         lakes.
                                                                                                       resource agency.
                                                                                                   ■   Know local, state, and federal laws.       U.S. Fish & Wildlife Service
                                                                                                                                                  Lower Great Lakes Fishery
                             Purple loosestrife (Lythrum salicaria) causes habitat destruction                                                    Resources Office
                             in wetlands.                                                                                                         405 North French Road, Suite 120A
                                                                                                                                                  Amherst, New York 14228
                                                                                                                                                  Phone: (716) 691 5456
                                                                                                                                                  Fax: (716) 691 6154

Martha Walter/GLSG Network

                                                                      Martha Walter/GLSG Network

                                                                                                                                                  U.S. Fish & Wildlife Service
                                                                                                                                                  1 800/344 WILD

                                                                                                                                                  July 2002

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