week of  2/20/02
 
 
 


The Naturalist's Corner
By Don Hendershot
An invading army is marching across the Southern Appalachians. Private citizens as well as state and federal agencies have unwittingly aided and abetted this enemy.

Over 900 species of non-native invasive plants have been identified as threats to native ecosystems and natural areas across the U.S. Over 200 invasive species have been identified within the Southern Appalachians. These exotics are destroying natural ecosystems, replacing native plants and reducing biodiversity.

The vast majority of these plants were brought to this country on purpose and nurtured and encouraged. Many are ornamentals, many are livestock forage and many were actually introduced by state and federal agencies responsible for the preservation of our wildlands.

Some of the more noxious invasives across WNC that were introduced as ornamentals include tree of heaven (Ailanthus altissima), oriental bittersweet (Celastrus orbuiculatus), princess tree (Paulownia tomentosa) and Chinese privet (Ligustrum sinense).

I have been battling oriental bittersweet in my backyard and at the edge of the woods surrounding my home for nearly six years and believe I am just now getting the upper hand. This fast-growing woody vine reproduces from seeds and sprouts and will completely overgrow and wipe out native flora.

Chinese privet is another particularly invasive exotic introduced as an ornamental. Along trails in the Great Smoky Mountains National Park, it is a tell-tale sign of past homesteads. Privet, which also grows from seeds and underground runners, can form dense thickets that out compete native plants.

The problem with introduced species is they have no natural biological controls. Once introduced they usually experience unrestricted growth. It is becoming more and more common across the region to see larger and larger areas of our mountains covered with kudzu (Puerania montana). Kudzu was introduced in this country from Japan at the beginning of the 20th century. Many state and federal agencies encouraged the planting of kudzu as a soil stabilizer and livestock forage.

Multiflora rose (Rosa multiflora) and various species of lespedeza (Lespedeza sp.) were (and some lespedeza still is) planted by wildlife agencies throughout the Southeast as wildlife food and cover. Multiflora rose spreads by seeds, root sprouts and by rooting where the arching branches touch the ground. It forms dense impenetrable thickets that prevent regeneration of native flora. Lespedeza also forms dense stands.

Invasive plants are a threat to rare and endangered species; they can create a loss of native food and shelter sources for indigenous species and alter natural plant communities and succession. They also create economic damage in the form of forage and timber losses and annual expenditures for eradication and/or control.

Many invasive species are still offered for sale at nurseries and plant retailers across the country. One report (Campbell 1997) estimates that nearly 67 percent of invasive forest vines — including kudzu — and nearly 90 percent of invasive forest trees are still offered for sale.

According to a recent Southern Appalachian Man and Biosphere report, land managers cite a lack of money and personnel, a lack of public, industry and governmental awareness and the lack of a central database with information on exotics as major impediments to the control and/or eradication of invasives.

A Feb. 25-March 1 conference in Washington, D.C., hopes to address some of these concerns. The conference: “National Invasive Weeds Awareness Week 2002” is being sponsored by the Invasive Weeds Awareness Coalition and the North American Weed Management Association. The event will be hosted by the Hilton Garden Inn and is open to individuals and organizations with an interest in invasive plant management.

For more information on the conference call 800.445.8667 or visit the website www.nawma.org/niwa.htm.

(Don Hendershot can be reached at don@smokymountainnews.com)