How Planting Natives Can Support Healthy Streams and Rivers
Spring beckons the nature lovers among us, especially the green thumbs, to explore and play outdoors. If you’ve got the gardening bug, you can cultivate a beautiful landscape that also supports clean water and healthy streams. How? With native plants.
What are Native Plants?
Flowers, trees, and shrubs are native to the regions where they grew before European settlement and the introduction of foreign species. They have adapted over a long time to local climate, soils, and other species. They are part of a finely tuned ecosystem as they feed and nurture one another. Birds, bees, and butterflies depend on seeds, pollen, and nectar from plants that are native to their region, and they, in turn, pollinate the plants they visit.
When non-native species enter the picture, they can outcompete native species and disrupt this delicate balance.
A Dietary Matter
Researchers have studied insect diets and found that among more than 7,500 plant-eating insect species from around the world, most, especially those closer to the equator, feed on just one plant family or species. This includes insects like monarch caterpillars that feed on milkweed.
Can insects adapt to eating non-native plants? Yes, but not always and not necessarily well.
Stroud Center scientist Bern Sweeney, Ph.D., has found that some aquatic insects struggle to survive when their native plant diets are replaced with non-native ones. In a 1993 study, he examined how mayflies and stoneflies from White Clay Creek responded when their diets, consisting of native species such as white ash, hickory, and American beech, were replaced with foreign species like multiflora rose, Asiatic bittersweet, and princess tree.
Larval survivorship among the mayfly species Leptophlebia cupida was consistently lower, even if the non-native diet seemed to provide adequate nutrition. When fed multiflora rose leaves, all the L. cupida larvae died. The stonefly Soyedina carolinensis fared better, indicating some species are more sensitive than others to non-native plant diets.
In a review of scientific research, entomologist, ecologist, and conservationist Doug Tallamy, Ph.D., and two coauthors found that while some insects can adapt to eating non-native plants, it doesn’t happen often enough to prevent insect populations from declining in areas where non-native plants have replaced native ones. He and his coauthors, therefore, suggest controlling the spread and use of non-native plants to support biodiversity.
Native Plants are Good for Water and So Much More
Because they are adapted to local conditions, native plants help you conserve water, and their deep roots reduce the erosion and polluted runoff that degrade freshwater ecosystems.
They’re also generally easier to grow, requiring little to no fertilizer or pesticides. And let’s not forget their scenic beauty and significance to local heritage.
Buying and Growing Native Plants
The Pennsylvania Department of Conservation and Natural Resources recommends that you refrain from removing native plants from the wild, as it depletes native populations, and many plants collected from the wild do not survive transplanting. Instead, DCNR says to look for nursery-propagated plants that are native to your region and suitable for your site conditions.
Your local plant nursery may have exactly what you’re looking for. There are many online resources as well. The National Wildlife Federation has a native plant finder and a companion site where you can buy native plants online.
Looking for native trees and shrubs for the mid-Atlantic region? Check out some of the species used by our watershed restoration team.
