A native plant is one that evolved over thousands of years in a particular region, introduced without human intervention, according to the U.S. Department of Agriculture. As native plant species evolved, so did native insects and wildlife, which rely on these plant communities for food and shelter. This preserves the balance of the native ecosystem, according to the South Carolina Native Plant Society.
For North America, only plants thriving in the United States prior to European takeover are considered native. On a regional scale, any plant that appears to naturalize (has migrated naturally without human intervention) in a new region would be considered non-native and some could be considered invasive, although not all non-native species are considered invasive. This original definition, however, was first agreed upon by conservation biologists in a time when climate was less understood and considered unchanging.
But some are challenging that today. Dov Sax, a researcher at Brown University, suggests a “more nuanced set of terms other than native and non-native” is necessary given the rapid shifts in ecological regimes due to climate change. A quick study of United States historical plant hardiness zones from the Arbor Day Foundation shows a dramatic change from 1990 to 2015, with warmer zones pushing northward. The shifting zones correlate with a northward shift in plant and animal communities potentially replacing or competing with others typically considered native. So the question is, if the naturalized species thrive in the current conditions, should it now be considered a native species?
Why does this matter? The definition of “native” is important because currently only those plants deemed native to a specific region are written into conservation legislation as those worthy of protection. As the climate changes and species naturalize into new areas that suit them for optimal growth and survival, would they be less deserving of protection?
Plant species migration is a slow process as they are not able to crawl or fly their way out of unsuitable conditions. Their rate of migration matters, as so many animal species rely on these plants for survival. There is already documented evidence of birds migrating to areas where the berries weren’t ready yet. The changes in ecological regimes and food availability can be detrimental to species both plant and animal and inevitably lead to extinction of species not able to keep up with change.
Human intervention could prevent extinction
A hot-topic in conservation right now to mitigate extinction is the idea of “assisted colonization,” in which plant species would be colonized in new regions outside of their native ranges that suit their optimal growing conditions. Researchers at prominent institutions in New England are reviewing all aspects of this debate including the pros and cons of relocation along with which plants would be good candidates for this conservation strategy.
There are definite concerns with ensuring that any relocated species would not become invasive or hybridize native plant species out of existence. The researchers found that many native species in New England might be more resilient to immediate climate change because their habitat ranges are so broad, however, many southern species would be extremely vulnerable to extinction because their native ranges are small.
Conservationists will need to grapple with the benefits and risks of accepting a new definition of native, and how to mitigate extinction due to habitat loss and fragmentation from human development and climate change. The hope is that the scientific community can quickly come to a consensus and to educate lawmakers so that we can possibly aid in the continuation of climate-threatened species.
A geologic perspective
In the not so distant past, flora and fauna were markedly different than they are today. During the last ice age (which ended about 10,000 to 12,000 years ago), mammoths, mastodons, giant ground sloths and saber tooth cats roamed the Lowcountry. The flora during that time would have been largely unrecognizable to what lives here today. Climates shift, habitats change and when we think about what it means to be native in this longer geologic context, perhaps those species migrating north are just returning home again. However, we should consider the influence of human activity on current warming and whether we are willing to let species go extinct on our account or help them thrive in ever changing conditions.
Toni Reale is the owner and creator director of Roadside Blooms, a unique flower and plant shop in Park Circle in North Charleston. It specializes in weddings, events and everyday deliveries using near 100 percent American- and locally-grown blooms. Online at: www.roadsideblooms.com. Visit at 4610 Spruill Avenue, Suite 102, North Charleston.
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