Against weeds: Guard against the invasion of non-native species
With diminishing habitat a threat, support for biodiversity is key
In her April 30 Ideas piece (“Got weeds? Read this before you whack them.”), Martha Leb Molnar makes a number of good points: Eradicating non-natives feels like a Sisyphean task; there is a difference between benign non-natives and those that outcompete natives; non-natives may offer sustenance to the insect population; there is little consensus about the definition of weeds; and non-natives can be beautiful.
What’s unfortunate is that she also advocates relaxing our position on removing non-natives. Ecosystems are complex webs of interrelationships among species. Host plants such as the oak support all life stages of hundreds of species. A bee might snack on a non-native plant, but that does not mean that plant offers sustenance throughout the bee’s lifespan. Native plants and insects have fine-tuned mutual support for millennia. Non-natives have not.
She asserts that species are not in decline, but of more than 250 species of bumblebee in the United States, a quarter are at risk of extinction. One reason for this risk is diminishing habitat. The sight of spicebush plants (host to the swallowtail butterfly) struggling to survive against invasive burning bush along a stream bed should impel us to action. Every delicate spicebush counts. Taking action to remove the most invasive non-natives (including the pretty multiflora rose, which Molnar mentions) and planting pollinator gardens is imperative to support biodiversity and the complexity of our ecosystems.
SARAH MEASURES
Maynard
One person’s casual yard observation is not the same as science
As an ecologist and master gardener, I was appalled at the April 30 Ideas article by Martha Leb Molnar about invasive plants and their supposed benefits to her meadow and our environment. Reporting on research into the issue would have been quite helpful. This statement alone — “Yet I see that the insects seem to like the non-natives and natives equally” — has been shown to be inaccurate many times over. It must be based on casual observations, which do not meet any research standards (for example, hypothesis, structured observations, data analysis). Such a statement spreads harmful misinformation. This article has the potential to do a lot of damage if readers believe Molnar and reduce their efforts to manage invasive plant species.
Readers who commented online were spot-on in recommending reading Douglas Tallamy (author of “Bringing Nature Home” and other books) and citing the Native Plant Trust.
JEAN O’NEIL
Williamsburg