The Battle with Alien Species was originally published in the BFEC Newsletter, Vol. 12/No. 1, Winter 2008.
Forget crop circles or Area 51; aliens landed at the Brown Family Environmental Center long ago... and they’re still here.
Some are unobtrusive, finding a niche amongst the natives and fitting in as best they can, like TV’s Alf. Others are not so benign; they creep and crawl over the landscape, overcrowding and suffocating the locals and generally making a nuisance out of themselves, more like the aliens from Independence Day.
That’s right, invasive plant species are among us. They are plants that are introduced to areas, through both accident and intent, that are able to grow and spread quickly and displace native species.
Not as glamorous as the bad guys from Superman II or the mucousy, acid-for-blood, little-mouth-coming-out-of-big-mouth creatures from Aliens, they are just as destructive if given the opportunity.
Outdone only by direct habitat destruction, invasive species are the second greatest threat to biodiversity in the United States.
Also described as alien, invasive, non-native, non-indigenous, exotic, introduced, weed and bothersome #$@!s, non-native plants have been intentionally introduced to Ohio for hundreds of years. Purposes have included horticulture, medicine, forage and erosion control. Multiflora rose, pictured, is one of the most prevalent invasive plants found on BFEC lands and was originally introduced to stabilize soil and act as a barrier to livestock.
The issue of invasive plant and animal species is worldwide and complex. In some instances, invasive species can bring national economies to their knees. In other cases, invasive species can actually be used to the benefit of an unbalanced ecosystem. More frequently, the situation is less straightforward, one in which presumed costs must be weighed against potential benefits all while keeping an eye on practicality.
Not all exotic species are truly “invasive.” Many non-indigenous plants do not actively take over native habitat; instead staying confined to areas where they are intentionally planted.
Truly invasive species employ a variety of strategies and exploit weaknesses in native defenses. They are typically characterized by rapid growth, high seed production and efficient seed dispersal. Plants like Japanese barberry can generate over half a million berries in a season.
Birds are more than happy to take advantage of this winter food source and become the unwitting agents of dispersal. Far away and safe from the predators and diseases that control them in their homelands, they easily outgrow their native neighbors with impunity.
The argument can be made that every species was at one point exotic; it had to come from somewhere, right? The reason is that ecosystems develop and achieve dynamic balance over a very long period of time. The speed at which invasive plants alter this balance by reducing habitat and species diversity can lead to a complete unraveling of the food web.
The Ohio Department of Natural Resources has compiled a list of the top ten invasive plant species, and Knox County plays host to all ten! Here’s a list of the ten least-wanted: Japanese honeysuckle, Japanese knotweed, autumn olive, buckthorn, purple loosestrife, common reed or phragmites, reed canary grass, garlic mustard, multiflora rose and bush honeysuckles. Add to that Japanese barberry and privet and you’ve got the BFEC’s "dirty dozen."
The BFEC is dedicated to conserving the native species and habitats of the Kokosing River Valley. Unfortunately, battling invasive species is a time and resource heavy pursuit. Therefore it is essential that we pick our battles carefully and fully commit to them when we do: triage.
The BFEC has begun work to reclaim one of our most heavily impacted areas — the hillside leading up to the pine plantation. For a time it was left largely to its own devices, and as a result, it had become seriously infested with multiflora rose and several other species on the “ten least-wanted” list.
Late last year, the entire hillside was cut back and this November saw the treatment of several of the most seriously impacted areas with herbicide. With the help of a US Fish & Wildlife Partners for Wildlife grant, we’ll be planting over three thousand mixed oaks next March. The current plan is to use the multiflora rose as a “living fence” to discourage deer browsing and to give the seedlings time to grow and shade out their protectors. We look forward to poetic justice.
Another strategy we’ve adapted to battle aggressive exotic species is to educate and lead by example. This year our showcase Wildlife Garden will feature more native species than ever before and our woodland and medicinal herb gardens will be following suit. Our planned pumpkin patch and squash garden will also feature a variety of native varieties. To bring the point home, we’re developing a series of educational modules that will allow visitors to learn more about native alternatives to exotics and how damaging something introduced because it’s “pretty” can really be.