Natural Heritage Committee  |  Non-native Invasive Species
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Why are Non-native Invasive Species a Problem?

Non-native Invasive Species (sometimes called "exotic" or "alien" species or just "invasives") are plants and animals introduced by people either accidentally or on purpose far from their native habitat. They may cause problems to natural flora and fauna because they:

  • grow and mature rapidly
  • are prolific     
  • spread rampantly
  • outcompete native species
  • are often free of natural controls such as disease, insects, or predators
  • have a high cost of removal and control

Invasive species cause economic harm, environmental harm or harm to human health. According to the Virginia Invasive Species Working Group, non-native invasive plants cause as much as $1 billion dollars economic damage annually in Virginia.

Not all exotic species are invasive, but all invasive species are recognized as introduced recently (post-European settlement) to North America. Damage caused by super-competitive invasive species is more prominent now than in past centuries because increased global trade and development has resulted in higher introduction rates of new species to smaller natural areas.  

    


Worst Invasive Species | What Can We Do? | Getting Rid of Invasive Plants | Additional Information


What are Some of the Worst Invasive Species in Albemarle County?

If you have driven along the highway and noticed kudzu or another exotic vine densely covering trees and shrubs, then you have noticed some of the damage that invasive non-native plants can cause in our area.  An invasive insect, the hemlock wooley adelgid, has devastated hemlock tree stands in Shenandoah National Park and other local natural areas.

The Virginia Department of Conservation and Recreation (VDCR) classifies non-native invasive plant species in Virginia using the following terms:

  • Highly invasive - exhibit the most invasive tendencies with the potential to disrupt ecological processes and cause major alterations in native plant and animal populations.  They establish readily and spread rapidly

  • Moderately invasive - may have minor influences on ecosystems by altering plant community composition and affecting community structure in one layer.  They may become dominant in one part of the community without threatening all of the species found there. They usually require a minor disturbance to become established

  • Occasionally invasive - do not affect ecosystem processes but may later plant community composition by out-competing one or more species.  They are often found in areas that have had a severe disturbance such as ice storm damage or road construction.  They spread slowly or not at all form the disturbed sites.

According to the VCDR, at least 27 highly invasive species of non-native plants are found in the Piedmont region (most of Albemarle County); 23 highly invasive species, in the mountains (the western part of the County).

Highly Invasive Alien Plant Species Widespread Across Albemarle County:

 

Highly Invasive Alien Plants In Isolated Locations of Albemarle County :

Non-native animals.
There is no complete list of non-native invasive animals as there is for plants.  Albemarle County has, however, experienced disruption of natural areas and species by some animal species such as European starlings, feral cats, exotic fish, gypsy moth, hemlock wooly adelgid, and the zebra mussel. 

Non-native microorganisms.
Non-native microorganisms (fungi, viruses, and bacteria) that have weakened or killed native plants or animals in Albemarle County include dogwood anthracnose, chestnut blight, and Dutch Elm disease, and West Nile Virus.   

 

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What Can We Do About Invasive Species?

 

Several invasive species (such as Oriental bittersweet and Japanese honeysuckle) are well established in Albemarle County. Complete eradication of well-established invasive species is not logistically and financially feasible with current resources and technology. 

With this in mind, invasive species education and control efforts by county staff and residents could be targeted to achieve maximum desired results with available resources using the below strategies.

  • Use early detection and removal as a way to prevent new invasive species from becoming established. Educate county residents and staff about potential new invaders to area before they become established to help prevent new invasive species problems.

  • Decide what areas and species are top priority for preservation in the county to help focus control efforts and education.  It is important to note that some invasive species have greater negative impacts than others.  A good starting point is to ask the question “why do we want to control invasive species in Albemarle County?” Some answers may include: to preserve native trees and forest structure, to have biologically diverse natural areas, to avoid having dense mats of invasive monocultures that may impede recreational activities in natural areas and aesthetic reasons. Answering why you want to control a particular plant or plants can help prioritize action.

  • When appropriate and feasible, support state and federal legislative efforts to introduce legislation that aids in the control of existing invasive species and/or preventing new invasions.

  • Encourage the recognition and use of native plant species by residents and county staff.  In his recent book, Bringing Nature Home, Douglas Tallamy of Delaware State University suggests that we are losing insect and bird diversity at an alarming rate in the U.S. in part because biological rich natural areas are being replaced with developed landscapes that are planted with just a few species of exotic plants.  Tallamy’s research also suggests that using native plants in landscapes can increase local biodiversity because native plants provide better food sources and habitats for native insects and birds than exotic plants do.  You can welcome birds, native butterflies and other fascinating creatures into your neighborhood by using native plants in your landscape.

 

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What are the Different Methods for Getting Rid of Invasive Plants?

Invasive plants are controlled using mechanical, biological and chemical control methods.  The method chosen depends on effectiveness of that method for a particular species, available resources, and the area where the plant is growing.

  • Mechanical control - is any control method that physically removes plant material, usually by pulling out by the roots or cutting.

  • Biological control - is any control method that removes plant material, kills a plant or limits its growth using another organism.  For example, leaf-feeding beetles (Galerucella spp) are used in some areas to control populations of purple loosestrife.  Purple loosestrife is an aggressive, invasive, wetland plant from Europe.  The leaf-feeding beetles are from Germany.  They feed on the plant and reduce the number of seeds produced and control the spread of new plants so purple loosestrife does not completely dominate a wetland.   The leaf-eating beetles have a strong preference for purple loosestrife so damage done to native plants is minimal. 

Goats are also used in invasive plant control and can be considered a biological control method.  Goats are relatively non-specific in their plant preference so they should only be considered for areas where desirable plants are not mixed in with invasive plants.

  • Chemical control refers to removing invasive plants by treating them with herbicides. Some herbicides are specific to treating certain plant types (e.g. herbicides with the active ingredient triclopyr are specific to broadleaf plants, especially woody broadleaf plants).  Some herbicides are non-specific (e.g. herbicides with the active ingredient glyphosate will harm all plants).  It is important to avoid hitting desirable plants with herbicides when treating invasive plants.

Herbicides also differ in their toxicities to animal species.  Herbicides with the active ingredients triclopyr and glyphosate are often used in natural areas because of their relatively low toxicities to animals.  All herbicides must be applied in accordance with instructions on the label. 

The different methods of control can be used alone or in combination. Sometimes combining herbicide treatments with mechanical and biological methods of control can reduce the amount of herbicide needed.

 

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Where Can I Find Additional Information about Invasive Species?

WEB SITES to learn more about Non-native INVASIVE PLANTS

1.   Virginia Invasive Plant Fact Sheets, including information on their control and on native alternatives to them; also a list of invasive plants in Virginia.  Natural Heritage Div., Dept. of Conservation and recreation. 

2.   Information on invasive plants in Virginia, and many other links. Virginia Native Plant Society web site

3.   Information about invasive plants in the U.S., including fact sheets. Plant Conservation Alliance. A publication covering 82 invasives in the Mid-Atlantic Region can be found in electronic form by adding: /pubs/midatlantic to the address above.

4.   Downloadable images of invasive exotic species in North America, The Bugwood Network.

5.   Invasive plants: information and control. The Nature Conservancy. This is nation-wide in its coverage.

6.   "Control of Invasive Non-native Plants: A Guide for Gardeners and Homeowners in the Mid-Atlantic Region". Maryland Native Plant Society.

7.   Voluntary codes of conduct for gardeners and commercial, professional and government groups whose actions affect the spread of invasive plant species. Missouri Botanical Garden web site, "Linking Ecology and Horticulture to Prevent Plant Invasions".

8.   "Nonnative Invasive Plants of Southern Forests, a Field Guide for Identification and Control" by James H. Miller. Forest Service, Southern Research Station General Technical Report SRS-62, May 2003. Request a copy hard copy at pubrequest@srs.fs.usda.gov. To print a copy use http://www.srs.fs.usda.gov/pibs/gtr/gtr_srs062/.
 
9.   Invasive plants of the southeast.
Southeast Exotic Pest Plant Council  links to other sites, including various state EPPC chapters.

10.  Invasive Plants: A Horticultural Perspective. Virginia Cooperative Extension

11.  Arlington County Virginia Invasive Plant Brochures. Arlington County Department of Parks, Recreation and Cultural Resources.  This page also includes a link to the brochure and wallet card entitled Potomac Watershed Invasive Species and Alternative Plants, which includes species also found in the Rivanna River Watershed.

12. United States Fish and Wildlife Service Invasive Species Information

 
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VDCR’s Invasive Plant Fact Sheets include plant descriptions, reasons why particular species are a problem and recommended methods of control. 

Also see below links from other sources for further information about invasive plant species found in Albermarle County and recommended control options.


 
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401 McIntire Road
Charlottesville, VA 22902
434-296-5832
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