News – University of Delaware researchers have highlighted the critical plants needed to maintain food webs across the United States.
Professor of Entomology Doug Tallamy is the lead author of a new study in Nature which drills down to the tallest plants in each county and bioregion, outlining a plan for how to restore ecosystems anywhere in the country.
Why do you care about food allergies? Well, these complex, highly interconnected systems of nutritional relationships are critical to the health of our planet. The Earth and its many species depend on them, including humans.
To start the festival, who has the first chair at the dining room table? The whole system starts with plants, which get good visibility for their ability to turn carbon dioxide into air and breathe. But lesser-known plants have other talents; they capture energy from the sun and turn it into food. Animals eat plants. Some eat vegetables directly; others get this energy by eating a plant-eating animal. And which animals are best for turning this energy into? Think small.
Going far above their weight class, insects are the best creatures on Earth at this energy movement. And the heroes of the world are caterpillars of the genus Lepidoptera, the lifeblood of the protein-rich food web that is perfect for hungry birds.
But caterpillars and other insects cannot thrive among any plants; they must be surrounded by native plants, meaning those that have evolved alongside insects over millions of years. For example, caterpillars in Delaware like the promethea siletoth do not flirt with popular trees like crepe myrtle, a popular choice for homeowners.
And not just any native plant will do that. The new research finds that most Lepidoptera are supported by only a handful of power plants. Ninety percent of what caterpillars eat is created by just 14 percent of native plant species with just five percent of power plants giving credit for 75 percent of food. This pattern is consistent wherever you go in the US
“Most talk of a food chain as if it were a series. In a diagram, these links look like a net rather than a simple chain,” said Tallamy, conservator and best-selling author. “Take a native stonecrop plant as an oak tree. More than 500 species of caterpillars can eat that oak tree. This allows for a more complex and, therefore, more sustainable food web.”
Native plants are known to be much better for the ecosystem than non-native plants, but this new study provides the experience another important step.
“There are some native plants, and of course there aren’t many of them, that do most of the work,” Tallamy said. “So if you build landscapes without those power plants that support caterpillars, the food web is doomed.”
Accompanying Tallamy in publishing the study were co-authors Kimberley Shropshire and former graduate student Desiree Narango, who is now a graduate researcher at the University of Massachusetts Amherst. Tallamy and Narango classified 38 as powerhouses among more than 2,000 plant genes. Native oak, willow, birch and wild cherry trees made the list of trees; the most powerful herbaceous plants included goldenrod, asters and perennial sunflower.
Tallamy, a veteran of conservation research, was amazed at the importance of the distinction between power plants and other native species.
“We were surprised by the magnitude of the differences. It’s not just a sustainable continuum where your native plants are lined up and, from one plant to the next, there’s a gradual decline in productivity,” Tallamy said . “He’s terribly tired of those power plants.”
Lepidoptera order of insects includes butterflies and moths. While butterflies are more respected for their beauty, the tastiest moth caterpillars do most of the work of transferring energy to predators.
“You hear a lot about butterfly gardens. We need to think more about Lepidoptera gardens that contain moths, which control the largest food web,” Tallamy said.
Today, due to human proliferation, toxins and species isolation, insect populations worldwide are declining sharply, known as Armageddon insects. Flying insects such as moths have seen a 78% decline over the last 40 years. Whether you love insects or are afraid of these six-legged invertebrates, their decline will affect you.
“Insects pollinate 90% of our flowering plants. Without insects, we would lose those plants, which fall on the food web,” Tallamy said. “We would lose amphibians, reptiles, birds, mammals and even a few freshwater fish.”
In addition to their energy transfer capabilities, insects are also essential for soil decomposition, releasing dead plant and animal material and returning nutrients to the soil. Yes, fungi and bacteria have this talent, but they are much slower than insects. Tallamy puts it hard.
“If insect numbers continue to decline, the Earth will rot. Humans will not survive through such a dramatic change,” Tallamy said. “Insects are essential not only for our well-being, but also for survival on Earth.”
So what can you do to help? As Tallamy details in his best hope in New York Times Nature’s Best Hope: A New Approach to Conservation that Starts in Your Yard, homeowners can turn their gardens into corridors conservation areas that provide wildlife habitats. They just have to choose plants that are native to their area.
“We need to change cultural norms the way our gardens should look like. Homeowners can reduce the size of their lawns,” Tallamy said. “But you can’t just replace the grass with old plants; choose key native plants that support local insects. If you’re in the middle of the Atlantic, choose from the 38 genes we’ve mentioned. Start with oak. Others, not the most beautiful on the list, but we have to learn to accept it. You may be planting black cherry in the back garden instead of outdoors. “
The same goes for public and non-profit efforts to restore ecosystems. Without power outlets, reform efforts fall short.
“Think of a basketball team. What if you only build a series of kittens and zero position players? They all play, but they’re lousy batsmen, so you’re going to miss the game, “Tallamy said. “Take these national and international initiatives [focused on forest restoration]. Planting trees is important, but we need the right line of power plants that are native to each region. “