Warding Off Invasives

It’s been a couple of years since I’ve written about invasives, and in those couple of years an incredible amount has changed. The effort to educate, eradicate and control invasives has taken several great leaps. Research in the control and understanding of many invasives has been fruitful, and public awareness seems to be at an all-time high because of all the publicity. My last rant on invasives was about purple loosestrife, a plant that invaded us from Europe long ago and during the past 50 years threatened to destroy freshwater and saltwater wetlands in record time. Locally, garden clubs took up the call and did their part to get this plant out of municipal plantings, and you no longer find it for sale either online or at local garden centers. Even more exciting is the fact that there are now viable biological controls that stop the spread of the plant and make it a manageable part of our wetland ecology instead of an imminent threat.This great success story comes from research to find control agents that primarily feed on this plant and are what we refer to as host-specific controls. In this case, we may have hit multiple jackpots, as there is a beetle that loves to eat the foliage (Galerucella), a weevil that adores the flowers (Nanophyes) and yet another weevil that munches on Lythrum roots (Hylobius). Between these three there have been some dramatic demonstrations of how these controls work, and there is one that shows a four-year progression from a near total wetland destruction to a balanced ecosystem in an area of Minnesota. You can use the link http://goo.gl/R3Ahz2 to see before and after pictures as well as a description of the project.

But then there’s rock snot. No, you won’t get it in your garden, and it doesn’t even exist on Long Island, but it’s an interesting story for anyone who wants to follow invasives. Rock snot (Didymosphenia or didymo) was “discovered” upstate a few years ago, and this discovery put fly fisherman and stream watchers in a panic. The state issued warnings to fishermen that the spread of didymo was extremely serious and that folks like trout fishers were probably the primary transporters of this algae, as they picked it up on their waders and moved from stream to stream and lake to lake. A protocol was established to clean the waders each time you exited a stream and certain waders were nearly outlawed because of their propensity to pick up the snot.

Well, if you read the State Department of Environmental Conservation web page on didymo, you can easily get the impression that the non-native algae invasion is pretty serious. But research published in Scientific American last May shows that rock snot is not an invader, is indeed native and has been around for quite a while. The issue, though, is that due to climate change and the resulting changes in our streams, rock snot is now being found in places where it wasn’t and, some say, shouldn’t be. You can find the article at http://goo.gl/R3Ahz2.

Closer to home we have our own new, really new, invasive issue. This one comes in the form of a small beetle that has a southern drawl. Last year the southern pine beetle was discovered on Long Island, and while not yet a disaster, this beetle does have the potential to do great damage on the East End, where Japanese black pines are planted by the millions and our native pitch pines can be seen in the gazillions in the pine barrens. Again, due to climate change, this beetle that was once perfectly happy doing its thing down south has migrated up to our area to play havoc. Not long ago it was the turpentine bark beetle that we feared, but now we may be in for a double whammy.

There are both federal and state efforts to understand this beetle better and to find ways to slow down its spread and even find natural controls for it. What’s a little unusual is that, while we’ve come to see invasive species as organisms that are inadvertently brought from Asia or Europe and get out of control here in the new world, between the southern pine beetle and rock snot we have two invaders that are natives or near natives. It’s thought that the southern pine beetle entered our area because of climate change and our warm winters. It’ll be interesting to see the numbers that come out this year, though, after two of the coldest winters in hundreds of years. Mother Nature may be striking a balance in our favor, but remember your high school genetics. All it takes is a few super-hardy beetles that make it though cold winters, and they can produce lots of … cold-hardy beetles.

When we talk about invasives, we sometimes get into a panic that sounds like “We’ve got to get this under control immediately.” But last week I was on a site walk for a proposed development in Westchester where there are some magnificent wetlands, ponds and a nearby river. The developer is trying to be respectful of these features and preserve them while still getting his development in. But on the site walk the damage from the truly invasive Oriental bittersweet was just remarkable: huge trees toppled by 4-inch-thick Oriental bittersweet vines and native shrubs smothered by thinner vines and tendrils. The knee-jerk reaction is that something has to be done immediately. And yes, something has to be done, but one glance at the ground showed that any effort at control would take years to decades of dedicated work, because for every square foot of forest floor there were 10 to 20 bright-red Oriental bittersweet seeds just waiting for an opportunity to sprout, stretch and do their damage. The quintessential seed bank.

Last summer I spent just about every weekend on a small piece of state-owned land in the Catskills. As a DEC steward for this land, one of my responsibilities is to find, report and control invasive species. Two years ago I found Vincetoxicumnigrum, better known as black swallow-wort. This is a plant that’s been around for years. It is native to Europe, where there are things that feed on it and control it, but those predators don’t occur here and we’ve learned that this viney plant that smothers our native plants is a real and serious threat to butterflies and nesting birds.

Black swallow-wort, which also occurs on Long Island, can grow from the ground up to 15 feet in one season, smothering every other plant in its path. If you pull it out it comes back with a vengeance. Most herbicides are ineffective on it, and deer won’t touch it. It’s got a very tiny but attractive flower that when pollinated forms a seed pod looking like a miniature milkweed pod, and it’s in the same family. When the pod is ripe the seed becomes windborne on feathery silks that can carry it for miles and miles, or just a few feet on the back of a passing deer. Troy Weldy, who heads the Nature Conservancy’s eastern New York region, said at an environmental conference last winter that he considers this plant one of the most environmentally dangerous invasive plants in our area. Last year I removed 30 bushels of vine and seed pods from an area of only 3,000 square feet.

There’s lots you can do. Get involved. Get educated. Volunteer. We need your help. Your garden needs your help. Find out how you can help by going to http://goo.gl/zqBwtd and clicking on “What you can do” on the left … and keep growing.