A recent NCF “Mornings for Members” walk at Windswept Bog (free to members of NCF with signup) highlighted some of our most beautiful native wildflowers. Natives are plants that arrived in a region without human help and in most cases have been in the neighborhood for enough time to become a vital part of the local ecosystem.
They’re not just pretty faces– each native plant is embedded in a complex web of relationships that has evolved over thousands of years. Plants aren’t interchangeable. However beautiful, an imported ornamental garden plant doesn’t share the a co-evolutionary history with local insects and wildlife that a native wildflower does. Take the tuberous grass pink, for example, (pictured above at left) — an orchid with a twist. The top portion of the flower is not what it appears to be — it looks like an attractive cluster of yellow pollen-bearing anthers, but it’s just a trick to attract a visiting insect, usually a bumblebee or long-tongued bee. As the bee tries to snag a pollen snack, the appendage folds down to temporarily trap the hungry insect, slapping it on the back with pollen that it won’t be able to reach. Rather than getting a pollen takeaway meal, the bee escapes, and if it falls for the trick again, cross-pollinates another grass pink flower. So, basically this flower appears bizarrely upside-down compared to other orchids (lip on top, not bottom). And it’s all a part of the complex ties in our local ecosystem that plants and animals and insects develop over a long timescale — ecological time.
Each region has its own “biodiversity fingerprint” of plant and animal species that have evolved together. Yes, plants and animals do move around without human aid, expanding their ranges as climate changes, or as seeds are carried on wind and waves. But those changes were usually slow and occurred few and far between, until modern times, when people became much more mobile and able to transport plants, animals, and diseases around the globe in great numbers and with great speed.
Nantucket’s “biodiversity fingerprint” is particularly distinctive because of the island’s history–it was once connected to the mainland, but then separated by sea level rise about 7,000 years ago. As a result, we share many of the same native plant communities that are found on the mainland of southern New England. However, our offshore location poised at the edge of two climate regions — combined with a long history of human habitation — have further shaped the island’s flora and fauna. Our island’s unusual biogeography has left us with number of prairie species to complement the more typical forest and shoreline habitats that are found in much of New England.
These prairie species and their relatives flourish in the island’s globally rare early successional habitats: sandplain grasslands and coastal heathlands. Protecting native plants also means protecting the insects that feed on them and are often needed for pollination. These relationships are often unnoticed by humans, but we can understand them better by examining the ecological ties of particular plants, like the grass pink and the milkweeds. While imported honeybees are much in the news these days, our native bees and a host of other amazing insects are also declining due to extreme and rapid alterations that humans have made to the environment. One of those major changes has been filling our yards with non-native ornamentals that insects and wildlife can’t use in the same way.
Introducing this same group of highly competitive plants to new places all over the world actually reduces the uniqueness of “biodiversity fingerprints” between regions. While these species will eventually form new ties and ecological relationships that include some native species, this process can take hundreds or thousands of years; in the meantime there are so many other stresses on our fragile ecosystems that the addition of aggressive new species can be enough to cause some rare and endangered species to decline or become extinct.
What can you do to help Nantucket’s native species survive and thrive? Be thoughtful in your own yard and retain native plants as landscaping — check out the new Nantucket Native Plant Pamphlet developed by the Nantucket Biodiversity Initiative to learn more. Your landscaper or local nursery can help you select native plants that benefit wildlife and insects, but you have to ask. Also, be sure to support island conservation organizations who work hard to protect native communities from development and slow the tide of introduced plants and animals.