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Giant Salvinia; Availability of an Environmental Assessment

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Animal and Plant Health Inspection Service, USDA.


Notice of availability and request for comments.


We are advising the public that the Animal and Plant Health Inspection Service has prepared an environmental assessment relative to a demonstration project to eradicate and prevent the spread of the aquatic weed giant salvinia in the Toledo Bend Reservoir and surrounding areas in Louisiana and eastern Texas. The environmental assessment documents our review and analysis of the environmental impacts associated with the alternative actions under consideration. Among the alternative actions considered in the assessment is a program using an integrated approach to eradicate giant salvinia from the Toledo Bend Reservoir and surrounding areas in Louisiana and eastern Texas. We are making this environmental assessment available to the public for review and comment.


We will consider all comments that we receive by August 23, 2001.


Please send four copies of your comment (an original and three copies) to: Docket No. 01-039-1, Regulatory Analysis and Development, PPD, APHIS, Suite 3C03, 4700 River Road Unit 118, Riverdale, MD 20737-1238.

Please state that your comment refers to Docket No. 01-039-1.

You may read any comments that we receive on this environmental assessment in our reading room. The reading room is located in room 1141 of the USDA South Building, 14th Street and Independence Avenue SW., Washington, DC. Normal reading room hours are 8 a.m. to 4:30 p.m., Monday through Friday, except holidays. To be sure someone is there to help you, please call (202) 690-2817 before coming.

APHIS documents published in the Federal Register, and related information, including the names of organizations and individuals who have commented on APHIS dockets, are available on the Internet at http://www.aphis,​ppd/​rad/​webrepor.html.

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Dr. Alan V. Tasker, National Weed Program Coordinator, Invasive Species and Pest Management, PPQ, APHIS, 4700 River Road Unit 134, Riverdale, MD 20737-1236; (301) 734-5225.

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Giant salvinia (Salvinia molesta) is a free-floating aquatic fern, native to South America, with a tremendous growth rate and the potential to significantly affect water-reliant agricultural industries, recreation, and the ecology of freshwater habitats throughout much of the United States.

Giant salvinia reproduces vegetatively through fragmenting and from dormant buds breaking away. A colony consists of many leaf pairs connected by branching rhizomes. The colony is easily broken, thus producing viable fragments. The colonizing or immature stage of giant salvinia is characterized by small leaves that lie flat upon the water. As the plants rapidly expand and compete for space, the leaves become larger, crowding occurs, and the plants are pushed upright. Mats may grow to a meter thick and can cover large areas. Giant salvinia grows best in stagnant or slow-moving water, and the plant can tolerate a wide pH range. While able to survive severe winters, giant salvinia grows best in temperatures ranging between 25 °C to 28 °C (77 °F to 81 °F).

Because giant salvinia is a free-floating plant, it disperses by passive means (water currents and wind) and by “hitchhiking.” Animals may carry the plants over short distances, but humans can spread it widely on fishing gear and boating equipment. Intercontinental dispersal and dispersal within the United States probably have occurred when giant salvinia was sold in the nursery trade, either intentionally as a plant for aquaria or for ponds, or unintentionally when it “hitchhikes” with other aquatic plants collected for academic study or for use in aquaria or ponds. Although native to southeastern Brazil, giant salvinia is now found in North America, South America, Africa, Asia, Australia, New Guinea, and Oceania.

The dominant characteristic of giant salvinia is its tremendous growth rate, which makes it an aggressive invader. Observations at the Toledo Bend Reservoir, which is located on the border between eastern Texas and western Louisiana, noted that a small, unobstructed patch of giant salvinia doubled in size in a few days during the winter of 1998-1999.

Where it occurs outside its native range, particularly in the tropics and subtropics, giant salvinia has become a problematic aquatic weed with the potential to choke irrigation systems, streams, and lakes. The mats also may harbor snails and insects that carry human and animal diseases. In a single growing season, giant salvinia can destroy a thriving water community by forming a destructive mass, halting transportation, killing fish, and promoting disease. Giant salvinia is considered a direct threat to rice farming. It gives off hydrogen sulfide (H2 S), which can damage copper components of hydroelectric generators. The thick mats, which can develop on open lakes, are avoided by small and large boats alike.

In the past several years, giant salvinia has been detected in the United States, mostly in association with the nursery trade in aquatic plants. Generally, detections have been in small, confined sites and are currently contained or have been eradicated. Such detections have occurred in Alabama, Arizona, Florida, Hawaii, Indiana, Louisiana, Maryland, Missouri, North Carolina, South Carolina, Texas, and Virginia. Of more serious and immediate concern is the current infestation in the Toledo Bend Reservoir and the surrounding areas in Louisiana and eastern Texas. The Toledo Bend Reservoir infestation is a major one in a large body of water.

The Animal and Plant Health Inspection Service (APHIS) listed giant salvinia as a noxious weed in 1983. Start Printed Page 38415Under APHIS' regulations, no person may move giant salvinia into or through the United States, or interstate, unless he or she obtains a permit for the movement from APHIS.

Because current efforts to eradicate giant salvinia in the Toledo Bend Reservoir and the surrounding areas in Louisiana and eastern Texas have been unsuccessful, APHIS has evaluated additional control methods available to help eradicate this noxious weed. These control methods include:

  • An integrated control approach utilizing herbicides and mechanical, biological, and regulatory controls.
  • A biological control program that requires no herbicide application.

APHIS' review and analysis of the potential environmental impacts associated with these control methods are documented in detail in an environmental assessment (EA) entitled, “Demonstration Project: Giant Salvinia, Toledo Bend Reservoir and Surrounding Areas in Louisiana and Eastern Texas” (March 2001).

The EA may be viewed on the Internet at​ppd/​es/​ppqdocs.html. You may request paper copies of the EA by calling or writing to the person listed under FOR FURTHER INFORMATION CONTACT. Please refer to the title of the EA when requesting copies. The EA is also available for review in our reading room (information on the location and hours of the reading room is provided under the heading ADDRESSES at the beginning of this notice).

The EA has been prepared in accordance with: (1) The National Environmental Policy Act of 1969 (NEPA), as amended (42 U.S.C. 4321 et seq.), (2) regulations of the Council on Environmental Quality for implementing the procedural provisions of NEPA (40 CFR parts 1500-1508), (3) USDA regulations implementing NEPA (7 CFR part 1), and (4) APHIS' NEPA Implementing Procedures (7 CFR part 372).

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Done in Washington, DC, this 18th day of July 2001.

Bobby R. Acord,

Acting Administrator, Animal and Plant Health Inspection Service.

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[FR Doc. 01-18389 Filed 7-23-01; 8:45 am]