Unwanted Species

By: Amy Campbell

And now for something different. These ruminations have been about plants or animals that we enjoy seeing around the watershed; often ones we thrill to seeing. This time, not so much.

This late summer I have noticed ever more areas that are overwhelmed by invasive plants. Even though in a watershed there is ever-present concern about introduction of invasive water plants that decrease enjoyment of recreation as well as having a negative effect on property values, invasive alien plants sure have an impact on land. And this can affect the wildlife that more and more we want to help preserve or encourage.

“A plant that is both non-native and able to establish on many sites, grow quickly, and spread to the point of disrupting plant communities or ecosystems” is a good definition of an invasive plant. Bottom line, they are nasty. Not being native, they have no natural controls (pests or diseases or animals that gobble them up ) so nothing will stop their spread. They push out native plants that do have benefit for the ecosystem, plants that provide food and shelter to any number of animals for example, or ones that collectively form a habitat for many species, each with different ecological roles. Unfortunately, and what doesn’t seem fair, sometimes these undesirables have lovely flowers. Think of purple loosestrife, ( Lythrum salicaria), with their spires of pink/purple flowers that spread too easily usually in wet locations. Another one is Himalayan balsam, or ornamental jewelweed ( Impatiens globulifera) whose interesting pink to white flowers entice bees and other insects to enter and collect nectar and pollen. I have seen people with out-of-state licenses stop to make photos where stands of this plant line Route 1 and have heard of people mowing around groups of these tall, pink-adorned plants in their yards. Stand back because the next year there will be more since the seeds spray out of the seed pods, guaranteeing their spread. Pretty flowers aren’t enough to justify the presence of an invasive plant. Time to go beyond that.

Other plants such as Japanese barberry (Berberis thunbergii) have brightly colored berries, and you might think, well, that is good for birds. Not so fast. The nutritional quality of many nonnative plants is not necessarily good enough to help birds put on enough weight for migration, for example. Many native berries are much higher in fat which has more calories ( don’t we know that!) needed for lengthy flights if not survival over frigid nights. Non-natives are high in sugar content, basically junk food in comparison. And in the case of barberry, an added negative feature is that it can increase the humidity in its local area to help disease-causing ticks survive.

Truly, isn’t it time to encourage property owners to take more responsibility for dealing with invasive plants on their land? At least the state has now banned the sale of some of the more ornamental species, but what to do about burning bush (Euonymus alatus)or Japanese honeysuckle (Lonicera japonica) planted years ago by former property owners? What about seedlings that arrive from a neighboring property? Some of these non-native plants are atrociously difficult to eradicate so vigilance is important. It’s easier to pull out a few small plants and keep them out than to be faced with a huge moculture. In England, (and I also heard of a similar case in Massachusetts) having Japanese knotweed substantially decreases the value of the property. Now that would get people’s attention.

When you look for invasives on your property, take care to inspect not only the area around the dwelling but also along the access road. We have found lots of seedling glossy buckthorn trees ( Frangula alnus) along our road, for example, and are trying to eliminate them. You might wonder where they come from in what seems like pristine forests, but often the seeds are ‘deposited’ by animals and birds. If you share a road with others, plan a day to get together your neighbors to search for and eradicate invaders. And don’t forget to have a plan to help keep the invasives from coming back!

I am continuously reminded of the famous quotation: “We do not inherit the earth from our ancestors; we borrow it from our children.” We need to keep this in mind and act accordingly. This is one place where we can make a difference.

Japenese Barberry

Purple loosestrife