What problems are invasive species causing and what is being done about them?

Welcome to the latest installment of the BayBlog Question of the Week! Each week, we take a question submitted on the Chesapeake Bay Program website or a frequently asked question and answer it here for all to read.

This week’s question came from Katherine, who asked, “What problems are invasive species causing in the Chesapeake Bay, and what is being done about them?”

Invasive species can be very harmful to the ecosystems they invade. Many invasive species thrive in their new habitats because they lack the natural predators and diseases that may threaten them in their native habitats. Without these things keeping their populations in check, invasive species are able reproduce and thrive.

However, invasive species seriously threaten our native plants and animals by encroaching on their food and habitat, often leaving native species without food or shelter in their natural environments. For example, mute swans can destroy bay grass beds while feeding. Without bay grasses, many other animals have nothing to eat or nowhere to take shelter, and the health of the Bay suffers as well.

It is estimated that about 42 percent of the native plants and animals listed as threatened or endangered in the United States are at risk for further decline due to invasive species.

Once established in a new habitat, invasive species are very difficult to completely eradicate. Controlling invasive species can be very expensive and requires a lot of time, cooperation and commitment among multiple agencies and jurisdictions.

A variety of control tactics are used, depending on the species and the state where the problem exists. In Maryland, mute swans have been successfully controlled to the point where only 500 were estimated to be present in the state in 2009. Water chestnut, an invasive aquatic plant, is controlled by hands-on removal. Scientists and volunteers remove the plants by hand, pulling them from where they grow in rivers and creeks so the plants are not able to spread their seeds. Water chestnut was thought to have been eradicated multiple times but has come back repeatedly, so the struggle to control it continues.

The best way to control invasive species is to not allow them to be introduced in the first place. Zebra mussels are one invasive species that you can help to control. If you boat in freshwater areas, make sure you wash your boat off thoroughly and let it dry completely so the mussels can't "hitchhike" to another water body.

If you spot an invasive species, notify the appropriate agency so that the proper measures may be taken to deal with it.

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