By Molly Igoe
Elm Staff Writer
In “Rebuilding Nature’s Relationships,” Professor of Entomology and Wildlife Ecology at University of Delaware Dr. Douglas Tallamy, discussed the important role that native plants serve in maintaining a healthy ecosystem. The main message from this lecture, sponsored by Washington College’s Center for Environment and Society (CES), is that we need to help restore biodiversity in our local ecosystems.
Dr. Tallamy has been teaching at the University of Delaware for 33 years, offering classes such as insect taxonomy, behavioral ecology, and insect ecology. He has written 80 research articles along with his most recent work, a book entitled “Bringing Nature Home: How Native Plants Sustain Wildlife in Our Gardens,” which was awarded the 2008 Silver Medal by the Garden Writer’s Association.
In his lecture on Feb. 12, Dr. Tallamy emphasized that every animal has a specialized relationship with a specific plant. He used the example of Carolina chickadees, which only feed caterpillars to their young; if there are no caterpillars, then there will be no chickadees. In a more general scope, 90 percent of insects can only eat plants that they share an evolutionary history with.
Dr. Tallamy said, “As a result of humans taking plants away from their natural ecosystems, many insects are on the verge of extinction.” The best-known case that supports this specialization problem is the monarch butterfly and the milkweed plant. The milkweed plant is the monarch’s main source of protein and as the milkweed has been dwindling due to farming, so have the monarch butterfly’s numbers.
The vital role that insects play in the food web cannot be overlooked. Dr. Tallamy said, “Almost every animal relies on insects, either directly or indirectly. Birds rely almost exclusively on insects for nutrients.” The 2014 State of Birds Report found that 230 species of birds are at risk of extinction in North America. This is a sobering statistic, one that can be attributed to lack of biodiversity in natural ecosystems.
Many studies have demonstrated that there is an enormous gap in the nutritional values that birds derive from non-invasive trees in comparison with invasive trees. “The invasive trees offer little nutritional value for the birds, because the trees are out of sync with the bird’s needs,” Dr. Tallamy said. This goes back to Dr. Tallamy’s main premise that an ecosystem will thrive if the plants and animals in it share a common history with each other.
Although this news can be interpreted as gloomy, he reassured the audience that this alarming trend can be reversed. He said the most effective way that humans can help reverse ecological damage is by building functioning ecosystems at home. This can be accomplished in a number of ways such as planting native trees along with non-native trees in your yard and reducing the area of manicured lawn around the home in favor of more trees and plants.
Dr. Tallamy suggested picking pretty plants that also have ecological value, not just plants for aesthetic appeal. The goals of managing your own ecosystem in your backyard range from supporting life to managing water and sequestering carbon. There are numerous advantages in creating a budding natural environment right outside your backdoor, one of them being that nature is thought to lower blood pressure and boost the immune system. This lecture brought to light just how vital it is for humans to maintain a diverse ecosystem in regards to plants and animals. The food web is a constant cycle, and when one organism suffers, the whole chain suffers as well. To ensure a successful ecosystem, we can start by planting native trees around our houses. This method is not earth shattering, but every little step helps positively impact our local ecosystem’s future. For information about what plants are native in your area, visit Dr. Tallamy’s website, bringingnaturehome.net.