Cheryl Kimball's Nature Talks: Invasive species are everywhereBy CHERYL KIMBALL July 21. 2018 12:19AM
The property I live on has its share of invasive species. Most of them, as far as I know, are plants.
The first one we tackled was Japanese knotweed. This crazy-fast-growing plant that most of us think of as bamboo was about to take over the house. At the very least, when it was at its peak of summer growth, it obscured the view of the carriage house from the main house which is maybe 75 yards. We pulled it and plucked it and hacked it and dug it up. It grew on an uneven banking that had a cement pad that once held a furnace for a small greenhouse. My husband felt that if we could level out the area, burying the knotweed, and then be able to regularly mow the area, we could get a handle on it. He was right. After 20-plus years, there is a mowable little lawn in that area instead of a knot of knotweed.
I suspect the bittersweet taking over the area behind the garage was planted, or at least encouraged by the previous owner for her crafting activities. We might be able to get rid of that the same way as the knotweed — turn it over, level it off, keep it mowed. But sadly we have accidentally introduced it to another area several hundred feet away. I also now find healthy and huge pokeweed all over the place, dispersed by birds I assume. Someone who is helping us clear out the stone wall along the road in the back yard discovered autumn olive, a shrub native to eastern Asia. The Nature Conservancy talks about how widespread it is in Indiana and describes it as “good intentions gone bad.”
That might also describe those bright red burning bushes — these are on the New Hampshire prohibited species list. A friend had four in the front of her house that were lovely little decorative bushes that apparently loved the spot she planted them in because they became so large you could no longer see out of the front windows. She had them cut down. They do have berries, which some birds love so one would think the birds would be spreading them. But to be honest I have never seen burning bushes randomly growing anywhere.
Wild grapevine is running rampant along the sides of the roads and around our property — every summer it threatens to pull down the dog pen fencing — but it is not on the invasive list. Milfoil is also not listed on the “prohibited invasive species list” but we certainly do a lot in New Hampshire to avoid and attack it in our lakes. Lake hosts sit beside boat launches all summer long checking boat bottoms for plants like milfoil that are fast growing and will choke out other species and deaden a lake. Even the little lake in my town has a milfoil program which includes the occasional hiring of divers who hand pluck the plant from the lake.
But plants aren’t the only invasives. We have heard a lot in recent years about the invasive and highly destructive beetles that can decimate a specific tree population — such as the Asian Longhorn beetle and the emerald ash borer that is threatening the ash tree. Even the little “ladybugs” (aka ladybeetles or ladybirds) that infest our window sills as the air chills in the fall were artificially introduced to this country. That they were introduced as predators of the destructive aphid make them considered more beneficial than pesty, but they have expanded in numbers large enough to start to elbow out other native aphid-eating species. The so-called stink bug is also an invasive to our area but doesn’t seem to have a big negative impact on anything except being creepy. See the website insectidentification.org for some great identifying information.
Another invasive along the seashore is the green crab which, according to the State of Maine Department of Marine Resources, came here accidentally, hitching a ride across the Atlantic from Europe in the ballast of ships back in the mid-1800s. Green crabs have been tagged as widely responsible for a dramatic decrease in the clam and mussel population. Zebra mussels are freshwater invasives that originated in Russia and Ukraine.
Birds are not immune to invasive species in this country. The European starling is said to have been brought to North America by Shakespeare enthusiasts, according to the Cornell Lab of Ornithology. It is now one of North America’s most numerous songbirds. The house sparrow (without the connection to the Bard) has a similar history. And our sweet songbirds from afar do the same as plants and beetles — they choke out native species by claiming all the best food and nesting sites. For a while, resident species can’t compete since they haven’t experienced the specific challenge. Some adapt and some do not.
Invasive species by definition are non-native and cause harm. Which makes me wonder where that leaves us humans. Maybe we are different because we tend to cause harm but then many times recognize our folly and try to correct it. Maybe.
Cheryl Kimball is a freelance writer who lives north of Rochester. Email her at email@example.com.