Association of State Wetland Managers - Protecting the Nation's Wetlands.

The Compleat Wetlander: Invasive Species: One Mans Trash is Anothers Treasure

A major problem on many wetland restoration projects including mitigation sites is the presence and even dominance of invasive species. An “invasive species” is defined as
1) nonnative (or alien) to the ecosystem under
consideration and
2) whose introduction causes or is likely to cause
economic or environmental harm or harm to human health.

They even have their own Executive Order: 13112
Excluded from this definition are species that are nonnative but considered beneficial. Honeybees and the common earthworm are both nonnative beneficial species.

There are many others. Once while working on a national wildlife program, I suggested (mostly to get a reaction) that we should stop funding management for pheasants in North America because they were an alien species It was a very short discussion. I lost.

Sometimes the benefits of a nonnative species are ambiguous. On a visit to the Island of Kauai I was surprised to see signs posted in a park informing visitors that the chickens were a protected wild species. Wild chickens? These chickens were apparently brought to the island by Polynesian settlers long ago and liberated—either by accident or intent. I thought this was hilarious until a wild rooster decided to crow outside my tent at 3:00 a.m.

Invasive species are a real threat. The Nature Conservancy estimates that invasive species have contributed to the decline of 42% of the threatened and endangered species in the U.S.. Nationally an area the size of California represents the area currently covered by invasive species. They cost the U.S. economy and estimated $120 billion annually.

The problem is often that a plant or animal from another part of the world is successful here because there are no natural predators. For example purple loosestrife is native to Eurasia, where it is not a nuisance species, presumably because there are plenty of insects that eat the plant as well as diseases that keep the numbers down.

But in this country purple loosestrife has taken over entire wetlands, crowding out all the native vegetation so that the wetland becomes a pure stand of purple loosestrife creating a ‘monoculture.’ It is found in every state except Florida.

Maybe one answer to addressing invasive species is to explore ways to make them useful. After all, if everyone wanted to harvest purple loosestrife because someone wanted to buy it—it would quickly become scarce on the landscape. Eradicating plants and animals that are destroying the natural landscape and creating jobs at the same time would be a great solution.

Is it even possible?

Purple loosestrife has been used for centuries as a medicinal plant. Phragmites, another invasive species (maybe), has been used to improve water quality, thatch roofs, and as a food source.

Straw bale construction of houses has been around for hundreds of years. What are the possibilities of using invasive species in the construction of green infrastructure?

We won’t know unless we try.

For more information about invasive species visit
National Invasive Species Information Center:
Center for Invasive Species and Ecosystem Health:

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