Why can’t we let nature take its course and just leave the alien plants alone?

Through eons of evolution by natural selection, living things adapted to their physical environment and the organisms around them in ways that enabled them to survive. These natural processes worked well within the ancestral setting that created them, but we humans have changed that setting drastically.

The plants and animals in today’s world have had no time to adapt to these sudden changes and so are still operating under the rules that worked before humans took over landscape management. The end result is that without direct intervention by the humans who have placed them at risk, most organisms will not survive under our rules.

Isn’t habitat destruction a more pressing problem than alien plants in the landscape?

Habitat destruction is a huge problem everywhere. That is precisely why we can no longer rely on natural areas alone to provide food and shelter for biodiversity. Instead, we must restore native plants to the areas that we have taken for our own use so that other species can live along with us in these spaces.

We can start by restoring native plants to our gardens. This is a manageable task for both suburban and city dwellers, with tangible results in a few short seasons as individual gardens begin to attract the birds and the insects that will sustain them.

My house sits on an eighth of an acre. Is that enough land to make a difference if I use natives instead of aliens?

Your small plot is connected to other plots, which are connected to others and others and others. Collectively they are North America. Changing the plant base of all of suburbia is quite an undertaking, but all you have to worry about is your eighth of an acre.

The important thing to remember is that even if you seem like the only one in all of North America who uses more natives than alien plants, wildlife will be better off for your efforts. The effects will be cumulative, and probably synergistic, as more and more people join you.

Why is biodiversity important?

Around 50,000 alien species of plants and animals have colonized North America. It is crucial to keep noncontributing alien species from displacing the native plants and animals that play a critical role in the ecosystem. This is best done by maintaining a full diversity of native organisms in an ecosystem. A diverse ecosystem has more niches filled by competing organisms and is able to more successfully resist invasion by alien species.

Why are native plants important?

Nearly every creature on the planet owes its existence to plants, the only organisms capable of capturing the sun’s energy and turning that energy into food for the rest of us. Because animals directly and indirectly depend on plants for their food, the diversity of animals is closely linked to the diversity of plants. When there are many species of plants, there are many species of animals.

Author Doug Tallamy

Professor of Entomology and Wildlife Ecology at the University of Delaware, Doug Tallamy has taught insect-related courses for 40 years. Among his awards are the Garden Club of America Margaret Douglas Medal for Conservation and the Tom Dodd, Jr. Award of Excellence, the AHS B. Y. Morrison Communication Award, and the Cynthia Westcott Scientific Writing Award. Doug is co-founder with Michelle Alfandari of HOMEGROWN NATIONAL PARK. Learn more at HNPARK.org.