The Importance Of Going Native

Marsh Marigold (Caltha palustris) is an excellent native plant for wet areas and rain gardens. Photo by Jonathan Townsend

The Chautauqua Watershed Conservancy has long been a proponent of native gardening and restoring ecosystems through the control of non-native species and the re-establishment of native plants. We have worked to do this on the network of over 1,000 acres of nature preserves that we manage, and we have spent years educating and assisting the public on how to install native gardens and lakeshore or streambank buffers. Why do we do this? Because sound science tells us that native plants are extremely important for a wide variety of reasons.

First and foremost, the fungi, plants, and animals of every ecosystem on Earth have spent millennia evolving and adapting to the species that have been present alongside them for all that time. Some species have been lost to extinction events, and some have evolved into other species. But for the most part, important ecological relationships have formed between almost all of these organisms, and they are crucial to maintaining healthy, functioning ecosystems.

Monarch butterfly larvae (Danaus plexippus) have a well-documented need for milkweed (Asclepias) plants, and this relationship is mirrored in many other insect and plant species. The milkweed plant (and nearly EVERY other plant in the world) itself depends on a type of soil fungus called mycorrhizal fungi to deliver nitrogen and phosphorus. The fungus provides these services to plants in exchange for sugar. This mutualistic relationship may have led to plants’ ability to colonize terrestrial ecosystems around half a billion years ago. Recent research now suggests that this important plant-fungi relationship may actually assist monarch butterflies in “self-medicating” to help them deal with a protozoan parasite called OE (Ophryocystis elektroscirrha). This fungus can act to increase the toxic cardenolides found in milkweed that monarchs consume as larva and store to defend against predation as adults. They apparently also use these compounds to decrease the infection from OE. Infected monarchs tend to prefer milkweed plants that have higher levels of these cardenolides, and mycorrhizal fungi tend to increase these levels. This four-way relationship between soil fungus, parasite, plant, and insect serves as one example among millions and highlights how complex and important native plants can be to their respective ecosystems.

Native plants also provide a wealth of resources for insects and their larvae, and these insects are eaten by just about everything – an extremely important ecological relationship. Most songbirds raise their young on these larva since they can’t travel far from their nests and must therefore find food resources close by. Non-native plants provide little food, and the edible berries that some do provide are of substandard nutrition and cause more harm than good. Gardening with native plants helps to offset this by providing a diversity of native species that can help rebuild these relationships. This is what the CWC aims to accomplish with our native planting and ecological restoration efforts. Our projects work to re-establish uncommon species and act as a reservoir that will spill out into the other habitats near our properties.

There are many other examples of how and why native plants are important to consider in our gardens, fields, and forests. One additional example relates to erosion and streambank/soil stabilization. Many invasive plants such as honeysuckle (Lonicera) and knotweed (Reynoutria japonica) have shallow roots that don’t reach down into the soil as well as native plants do. On hillslopes and streambanks, this can lead to erosion and sedimentation in our waterways, which translates into degraded water quality. Chautauqua Lake is a good example. Knotweeds also pump “allelopathic” chemicals into the soil, which disrupt the mycorrhizal relationships underground and prevent other plants from growing. Not only does this quickly lead to a knotweed-dominated streambank, but it also leaves bare soil open to water and wind action which further exacerbates erosion. Phragmites is another invasive plant that can dominate wetlands, steambanks, and ditches. This species grows quite tall (up to 15 feet), and the dead canes remain standing well into the winter. These stalks are slow to break down, and over the years, they pile up and can eventually affect wetland hydrology – converting a wetland to an upland. This translates into a number of ecosystem-level impacts, as well as a reduction in the water filtering action that wetlands provide, again impacting water quality downstream.

When it comes to native plants, there is no comparison! For gardeners, these species are hardy, tolerant of a wide variety of growing conditions, and require less maintenance than horticultural varieties. Some may prefer exotic non-native flowers for their obvious beauty – however, Chautauqua County has numerous native wildflowers which are so unique that many would think they must be tropical. Less maintenance, less effort, and a strong benefit to the environment? How can anyone argue with that?!

The Chautauqua Watershed Conservancy is a local not-for-profit organization dedicated to preserving and enhancing the water quality, scenic beauty and ecological health of the lakes, streams, wetlands and watersheds of the Chautauqua region. For more information, call 664-2166 or visit www.chautauquawatershed.org or www.facebook.com/chautauquawatershed.

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