Why Are Native Plants Important?
Native plants have co-evolved with native herbivore insects, pollinators, birds and mammals to form our once thriving ecosystem. With ever-increasing development and habitat destruction, our gardens and landscapes play an essential role in connecting fragmented natural areas.
Plants serve a necessary role in our wonderfully intricate food web, as they are the only organisms in our ecosystem capable of converting the sun’s energy into food for the rest of us. Most animals in higher trophic levels rely on herbivore insects to access this energy. Birds are a great example, about 96% of terrestrial birds rely on insects and other anthropods to feed their young.
Like the beautiful, well-known Monarch butterfly, 90% of herbivorous insects are specialists that can only eat certain plant lineages that they have co-evolved with. These specialist insects have developed niches by evolving to detoxify secondary metabolites created by certain genera or even specific species within one genus of plants. By planting native plants we support the diverse populations of herbivorous insects that exist in our ecosystem.
For some numbers:
The incredible oak genus (quercus) hosts 534 species of lepidoptera (moths and butterflies) in the northeast.
The non-native Lagerstroemia genus that includes Crepe Myrtle supports less than 10 species.
By supporting more herbivorous insects, we also support higher populations of their predators (other insects and birds) who in turn keep their populations in check, so that no one species is able significantly damage your plants. This also provides great benefit to your vegetable garden! Your native plantings will provide year round specialist insects to keep the predators around, who then step in whenever an agricultural pest comes along.
This is a call to action for you to use your landscape to help preserve the biodiversity of our ecosystem, by choosing plants that support herbivorous insects, bees, butterflies and birds! Better yet, the native species that you plant will become seed sources that birds will use to restore the our natural areas!
Tallamy, D. W. and K. J. Shropshire. 2009. Ranking Lepidopteran use of native versus introduced plants. Conservation Biology 23: 941–947