Invasive plants spell species mono-culture
Misery does love company in many contexts, and I therefore took heart when NHPR ran a two-part series on invasive species last week on Laura Knoy’s “The Exchange” program.
Invasive plant and animal species have become one of the top two threats to the natural world. And yet, in our attention-distracted world, they receive little attention.
Laura Knoy’s two shows on the subject is a sign that attention is being paid.
About misery, those few who do know about invasive species notice purple loosestrife taking over a wetland while landscape painters and photographers set their easels and tripods up to capture the perceived beauty. They see bittersweet’s tangle of vines choking the forest while fall ornamental displays include wreathes of the vines with their orange berries. In fall, they can’t help noticing the bright red foliage of burning bush euonymus, escaped into wild areas from home gardens and commercial landscaping where it’s one of the most popular shrubs.
Had I a magic wand, these scenarios would cause misery in all viewers, and we all would band together in vigilance against these enemies of the natural world.
Vigilance was the message of the NHPR programs: early detection by watchful volunteers. After an invasive species is established, its rampant spread is difficult to stop.
The program also made it clear that the term “invasive” is applied with great care and only after a protocol that determines damage done. Ecological, economic, recreational and health impacts are all part of the consideration.
A distinction was made between invasive and nuisance plants like poison ivy; and the many non-native, introduced plants that fit in with the general mix without extreme negative impacts.
We’re surrounded by non-native plants, but only a handful fall in the “perfect storm” category — perfectly and perversely suited to take over and push out the locals.
Invasive species by definition are winners in resource competition — hogging light, water, nutrients and space at the expense of what was a normal, healthy mix of plants. A species mono-culture is the final outcome — at the great expense of natural resources as well as forestry and farm resources.
Federal and state lists of invasive species have been compiled, and in most states the sale and transport of certain plants is banned. Burning bush euonymus was one of the first plants banned in New Hampshire, one of the first states to take action.
In my magic wand world, we wear t-shirts with a Ghostbusters logo appropriate to repelling the invaders. “Pulling Together” is a coastal program focused on estuaries and “Weed Watchers” is a volunteer-driven program in the Lake Winnepesaukee area. I don’t know if they have t-shirts, but those catchy phrases have potential and suggest a community effort. Misery found company and got to work.
To help fuel concern (misery), and action, here’s information from the NHPR program about two invasive species:
Black swallow-wort is on the New Hampshire invasive plant list, but I don’t think it’s shown up in this area yet (all the more reason to be vigilant). It’s a ground-hugging vine with thick dark-green leaves. Small pods that disperse parachute-like seeds in late summer give it away as a member of the milkweed family.
We all known that monarch butterfly females lay their eggs on milkweed plants, as that’s what emerging monarch caterpillars (larvae) feed on. As a really dirty trick on a species that already has enough challenges, monarch larvae that eat black swallow-wort leaves don’t survive.
Garlic mustard is an invasive that definitely has arrived in the area, usually hitching a ride on roadside fill put down by road crews fixing washouts. It spreads aggressively into adjacent natural areas.
Like several invasives, garlic mustard produces chemicals that suppress the competition — a process known as allelopathy. In the case of garlic mustard, the chemicals short circuit the beneficial relationship between native trees and a network of fungi attached to their roots that assist their health by delivering significant additional nutrients and moisture.
The fungi-tree root relationship is an invisible, sophisticated, mutually beneficial relationship, long in the evolutionary making — broken up by garlic mustard. The trees weaken, more sun is delivered to the plant, and it spreads.
Lincoln, Mass., not far from here, has an annual spring garlic mustard pull, complete, I think, with t-shirts.
Progress is being made insofar as awareness, assisted by presidential executive orders, state and federal committees, and some funding especially when agriculture and waterways are threatened.
As often is the case, the appropriately named grass-roots level of local volunteers is critical.
A good place to start is with the booklet put out by the N.H. Department of Agriculture titled “New Hampshire Guide to Upland Invasive Species.” An Internet search for the title delivers you to the pamphlet and its color photos and write-ups of each species on the New Hampshire list. There are about 30 plants listed, but I pay special attention to about a dozen.
The author, Doug Cygan, travels the state often to give talks on the subject to any interested group. The pamphlet has his contact information.
I’m writing this Tuesday, my birthday. My birthday tradition is to explore a favorite natural area in search of a new butterfly or wildflower species. In the process, I will pull up or clip back invasives as encountered. As antidote to misery, taking action gives satisfaction.
Backyard Birder by Francie Von Mertens appears every other week in the Monadnock Ledger-Transcript.