The invasive sea squirt Didemnum lahillei. Credit: USGS Woods Hole Science Center
The phrase invasive species is a relative term. Almost everything has been invasive at one point. The house sparrow that sits at your bird feeder – an unwanted gift from English sailors. The green seaweed that coats the Massachusetts seashore – an Atlantic hitchhiker. A species is invasive when it can’t coexist with the native creatures, whether by stealing food or shelter.
With climate change on the loom, species are going to get a whole lot more invasive as they migrate to warmer or colder regions. This poses not only an environmental risk but a health risk as well, especially if the traveling critters happen to be mosquitoes, for instance. In a few centuries, the phrase “native species” could be obsolete.
New England has it’s own share of invasive creatures. Here’s a list of four in our backyard:
The Sea Squirt (Didemnum lahillei)
This tubular sea squirt, an underwater resident of the Pacific and Europe, has overtaken spots on the seashore ranging from Maine to Connecticut. It first grabbed the attention Cape Cod residents in 2003, when the Boston Globe reported sea squirt colonies carpeting the water off Georges Bank, hindering scallop fishing.
Emerald Ash Borer (Agrilus planipennis)
This green beetle has been causing all sorts of havoc in the Middle States since turning up in Detroit in 2002. Originally from Asia, the bug has killed millions of ash trees, the main staple of its diet, and is heading for the Northeast. A few days ago, the Associated Press reported the use of a wasp to hunt and kill the pests, a quick and environmentally friendly solution to an agricultural disaster.
Norway Maple (Acer platanoides)
According to a member of EarthWorks, an ecological awareness organization located in Greater Boston, one familiar site on the streets of Boston is also an invasive species – the Norway maple. The tree, a favorite for the streets of small towns and cities, easily wins the resource battle against native North American trees like the red maple or native oaks. The article’s author advises against planting them in your yard.
Phragmites (Phragmites australis)
Anyone who has been to a salt marsh has seen these long reeds sticking out from the sand dunes. Their red stalks making an attractive backdrop against the blue water. But in areas full of protected plants like Sandy Neck Beach on Cape Cod, phragmites, native to Europe and Asia, can be a real nuisance. According to a WCAI report, residents and conservation organizations have to schedule regular “mowings” to keep these grasses at bay.