Parrotfeather

Introduction

Invasion by exotic species, along with improper resource use and pollution are among the major causes of natural resource problems today. Non-native, invasive species destroy natural ecosystems by out competing natives for limiting resources; in some cases, they reduce biological diversity. Parrotfeather ( Myriophyllum aquaticum) , an aquatic plant native to South America, was introduced to Washington State for use in aquaria. However, the plant is now known to have escaped into two river drainages. While parrotfeather may provide cover for some aquatic organisms, it can seriously change the physical and chemical characteristics of lakes and streams. Infestations form monocultures and can alter aquatic ecosystems by shading out the algae in the water column that serve as the basis of the aquatic food web. In addition, parrotfeather infestations can block water flow, resulting in increased flooding.

In 1994, parrotfeather was found in the Chehalis River in southwestern Washington. The second largest river basin in the state, the Chehalis provides habitat for a variety of salmonids, including coho, chinook, and chum salmon, and steelhead and anadromous cutthroat trout. Sloughs and other slow water habitats support populations of the Olympic mudminnow, a species of special concern in that it's restricted to coastal streams in Washington. Parrotfeather threatens the habitat of these species by lowering productivity and pH., as well as causing severe dissolved oxygen problems. Parrotfeather can have a particular impact on salmonids, since it occupies fry rearing habitat.
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Objectives

The parrotfeather infestation in the Chehalis River appears to be new, but the full extent of the infestation is not yet known. Scattered infestations have been reported between river miles 67 and 39. Because parrotfeather can reproduce by fragmentation, it could colonize the entire river system if action is not taken. Currently, control work is hampered by a lack of information on effective control strategies. Therefore, the project proposes to find effective ways to stop the spread of parrotfeather and control the existing population. To fully accomplish this goal, Lewis County is committed to a multi-year project.
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Activities to Manage Parrotfeather

There has been a strong showing by landowners and resource managers to be good stewards of the Chehalis River and the resources it provides. Support for the project has also come from the Chehalis Watershed Council, a group formed to address watershed management concerns and to deal with issues prior to resource degradation. The council has a diverse membership of citizens and agency personnel that represents the broad interests of the watershed.
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Cooperators

This project will be coordinated by the Lewis County Noxious Weed Control Board with an advisory group of scientists from the Washington Department of Ecology (WDOE), Portland State University, and the Washington State Noxious Weed Control Board.
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Description

Parrotfeather has both emergent and submersed leaves. The submersed leaves are finely-dissected, and feathery, often with a reddish color. The submersed growth form of parrotfeather is easily mistaken for Eurasian watermilfoil (Myriophyllum spicatum L.). The emergent stems can be from a few inches to over a foot high and are the most distinctive feature of parrotfeather. Emergent leaves form in whorls on the stem. Leaves are bright green and finely divided. In spring, very small, white, tuft-like flowers form where the emergent leaves attach to the stem.
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Growth Habit

Parrotfeather grows best when rooted in shallow water. In nutrient-enriched lakes parrotfeather can grow as a floating plant in deep water. The emergent stems can survive on wet banks of rivers and lake shores, so it is well adapted to moderate water level fluctuations. Parrotfeather's distribution in Washington is thought to be limited to coastal lakes and streams and the Columbia River in southwest Washington. Parrotfeather invasion of lakes and streams severely changes the physical and chemical characteristics of the aquatic ecosystem. The emergent stems shade the water column eliminating algae growth, which is the basis of the aquatic food web. Parrotfeather is also excellent habitat for mosquito larvae.
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Propagation

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