If you’ve hiked the trails of Presqu’ile you’ll notice that there are some areas where only one or a few plants grow, and quite often these will be non-native invasive species like Dog-Strangling Vine, Garlic Mustard, Common Buckthorn or Phragmites (left photo.) What gives the invasive plants the leg up over native species is the fact that the predators and diseases that can control them in their home range are left behind. Such constraints usually don’t exist in their new environments.
Reproductive and chemical warfare strategies also contribute to their spread and their effects on native species. Both Dog-Strangling Vine and Phragmites reproduce by both seeds and rhizomes. The seeds are windborne and allow the plants to establish themselves in new areas. Rhizomes are underground stems that can be quite long, and they can run deep. They branch, and new sprouts occasionally head for the surface, producing new plants adjacent to the original parent. The Marsh Boardwalk is a great place to get a sense of this, particularly in areas where park staff have to cut the canes too so that the boardwalk is passable.
So, what’s the chemical warfare story? Many plants exude chemicals from their roots, some of which inhibit the growth of other plant species. By doing so, invasive plants reduce biodiversity and can compromise habitats for other species. For example, if you’ve seen the density and structure of Phragmites along the marsh boardwalk, imagine being a hard-shelled turtle trying to move through the area - you can’t!
What are we doing about it? If you’ve experienced acne, eczema or arthritis, you come to realize that some things can’t be cured, but rather only managed. Invasive plants are no different. At the park a variety of methods are used, and these are informed by understanding the biology of the plants and what types of treatments are effective. In the past we’ve had school groups participate in Garlic Mustard pulls. Park staff and Friends’ volunteers use power tools to cut down and remove invasives such as Buckthorn. Prescribed burns and mowing can be effective tools. Sometimes herbicides are the only solution, and fortunately there now some herbicides that are quite effective and quickly degrade into nontoxic compounds. By employing a combination of techniques and being vigilant, year after year, we will be able to reduce the detrimental effects of these invaders.
What can you do? Try not to disturb invasive species. The feathery seeds of Phragmites wafting in the breeze can look pretty, but don’t spread them on purpose and don’t walk through them, as some of the seeds have barbs that allow them to cling to clothing, only to be released elsewhere. In that regard, keep your dog out of them. You can also contribute by volunteering. If you’re interested, let us know by filling out a volunteer form by clicking here. Become a Friends of Presqu’ile member by clicking here or consider making a donation to our environmental fund by clicking here.
