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Best Management Practices (BMPs) to Prevent the Introduction and Spread of Invasive Species


Developing Best Management Practices for Invasive Species

Land managers are facing increasing pressure from invasive plants, animals, insects and plant pathogens on the lands they own and manage. Furthermore, many land management practices used for forestry, agriculture, wildlife and recreational habitat management involve periodic disturbances that favor the introduction and/or spread of invasive species.

Most natural resource managers are familiar with the concept of Best Management Practices or BMPs uses in forestry as guidelines for recommended practices to protect water and soil resources during management operations such as timber harvests. As invasive species threaten more lands in the South, land managers can use BMPs for invasive species by developing a proactive approach to invasive species identification, documentation and control on their properties. To accomplish this, landowners must develop an awareness of the potential for the introduction and/or spread of invasive species as related to “normal use or management on their lands”.

Key BMPs for invasive species management (adapted from Wisconsin Council of Forestry 2009)

Landowner and consulting forester examining Japanese climbing fern in a stand scheduled for timber harvest.
Landowner and consulting forester examining Japanese climbing fern in a stand scheduled for timber harvest.

This information highlights invasive plant, animal, insect and plant pathogen issues that landowners might encounter and provides guidelines for preventing their introduction and spread. Landowner and consulting forester examining Japanese climbing fern in a stand scheduled for timber harvest.

Many landowners unknowingly introduce and spread invasive plants on their lands through management practices they implement. Practices, from traditional silviculture to wildlife enhancement and agricultural land-use all influence invasive plant growth, production, and dispersal. During the planning stage for any management project, document existing invasive species and develop plans with your forester, contractors and vendors to keep from spreading existing invasives or introducing new ones.


General Principles to Reduce the Impact of Invasive Plants

Land Management Practices

Harvest Activities

Skidding can spread invasives across the harvest tract.
Skidding can spread invasives across the harvest tract.

Harvest activities include practices in which trees are harvested, such as regeneration cuts (for example, shelterwood, seed tree, and group selection), thinning operations, or clear cuts.

Habitat Alterations:


Prescribed Fire

Prescribed fire can be used to control certain invasive species and spread others.
Prescribed fire can be used to control certain invasive species and spread others.

Prescribed fire is the practice of using fire, intentionally set, to obtain certain management objectives. Often prescribed fire is used to inhibit establishment of undesirable species or to set back succession. The use of prescribed fire also includes creation and maintenance of fire breaks.

Habitat Alterations:


Internal Roads and Stream Crossings

Road construction uses off-site materials which may contain invasives.
Road construction uses off-site materials which may contain invasives.

Roads are often built within a parcel of land to enable the owner/manager to move equipment and reach remote areas. Included within this category is the creation and maintenance of internal roads and stream crossings.

Habitat Alterations:


Mechanical Site Preparation

Site preparation creates bare soil and high light environment conducive to invasive establish­ment and spread.
Site preparation creates bare soil and high light environment conducive to invasive establish­ment and spread.

The practice of site preparation (or site prep) manipulates the ground layer to achieve a better microclimate for seedling establishment and growth. Site prep often follows a clearcut treatment and precedes planting. Common mechanical site prep treatments are: bedding, chopping, and disking.

Habitat Alterations:


Tree Planting

Tree planting equipment may harbor invasive seeds or plant material.
Tree planting equipment may harbor invasive seeds or plant material.

Tree planting includes the practices involved in planting seedlings. Seed bed preparation treatments, such as scalping and sub-soiling, and seedling planting are included within this category.

Habitat Alterations:


Release Treatments (Intermediate Treatments)

Release treatments create high light environments conducive to establishment of invasives.
Release treatments create high light environments conducive to establishment of invasives.

Release treatments are used to free small trees from competition from undesirable vegetation. Treatments include herbicide, mowing, cutting, and fire.

Habitat Alterations:


Special Considerations

Pine Straw Production

Pine straw production
Pine straw production

Many pine stands are managed for pine straw production. The needles that are naturally shed from pine trees are raked, baled, and sold as pine straw mulch. Pine straw production involves managing stands for optimum straw production, removing understory vegetation with herbicide and/or fire, collecting (raking) the straw, and making bales.

Often practices such as prescribed fire, mowing, and herbicide treatments are used in production areas. Stand alterations include soil disturbance, removal of understory and midstory, and increased light to the forest floor. Bales and equipment from infested stands can foster the widespread distribution of invasive plants.


Wildlife Enhancement

Wildlife food plot
Wildlife food plot

Wildlife enhancement involves any practice that can improve or enhance the wildlife habitat on a land, such as food plot installation, fertilization, and selective thinning and planting. This is a varied category but can include aspects of other silvicultural practices. Wildlife enhancement practices are a common avenue for invasive plant introductions, either via contaminated equipment or intentional planting. Areas to monitor for any invasive plants are camps, food plots, and other areas used.


Streamside Management Zones (SMZ)

Forest stream
Forest stream

These areas are protected because of water quality and erosion concerns. They can be refuges for invasive plants which can spread into adjacent lands. Since SMZs are adjacent to drainages, streams and rivers, invasive plants that favor wet areas, streamsides, or bottomlands are likely to be present. Conduct annual inspections to detect establishment of invasives, particularly, following flooding events.


Land Use Conversion

Newly planted pine stand invaded by kudzu
Newly planted pine stand invaded by kudzu

This category covers practices used when converting lands previously under cultivated agriculture or pasture into trees. A different suite of invasive plants can become problems in areas undergoing land use conversion. Established invasive plant populations or viable seedbanks may exist in surrounding agricultural fields or pastures. Fencerows may serve as a harbor for these invasives. A plant that was a minor pest in the previous land use may not be inhibited by the current management practices and suddenly expand its population drastically.





General Guidelines for Risk Reduction: Early Detection Through Monitoring

Harvest tract with SMZs and fencerows
Harvest tract with SMZs and fencerows


Best Management Practices for Activities Involving Soil Disturbance

Road maintenance
Road maintenance

Best Management Practices Involving Off-site Material and Equipment


Best Management Practices for Revegetation

Applying mulch for soil stabilization
Applying mulch for soil stabilization
Native longleaf wiregrass stand
Native longleaf wiregrass stand


Best Management Practices for Prescribed Burns

Carefully plan all prescribed burns and identify and map invasives found in the burn tract. Determine the interactions between the invasives and the planned burn.


Other Invasive Species Concerns

Firewood stacks
Firewood stacks

Many properties are leased or used for hunting, fishing, camping and other recreational uses. Movement of firewood, boats, ATVs, equipment used for habitat management, food plot establishment and other activities can unintentionally introduce invasives. Landowners should meet with all property users to infom them of invasive species concerns and BMPS required to prevent their introduction. Ask users to report invasive sightings.

One important key is to use only local firewood as many serious invasive insects and diseases can move on firewood from infested areas.

Emerald ash borer
Emerald ash borer

Emerald Ash Borer has a broad distribution in the United States and Canada and was recently discovered in East Tennessee in July 2010. The widespread distribution is primarily due to the transportation of infested ash commodities such as nursery stock, unprocessed logs, firewood, and other ash tree products. Federal and state quarantines in infested states now regulate transport of these products.

Asian long-horned beetle
Asian long-horned beetle

The Asian long-horned beetle is known to attack at least 18 species of hardwood trees including maple, birch, horse chestnut, willow, elm, ash, and black locust.

Adult Sirex woodwasp
Adult Sirex woodwasp

The Sirex woodwasp, while not yet found in the South, can attack loblolly, slash and shortleaf pines. The female drills into the wood and inserts a toxic mucous and the fungus Amylostereum areolatum along with her eggs. The mucus prevents anti-fungal toxins from being formed at the site of infection. The fungus grows in the wood causing it to dry out and the trees die in a few weeks or months.

Thousand cankers disease symptoms
Thousand cankers disease symptoms

Thousand cankers disease has been found in many Western States. The first confirmation of the beetle and fungus within the native range of black walnut was in Tennessee (July 2010). The potential damage to eastern forests could be great because of the widespread distribution of eastern black walnut, the susceptibility of this tree to the disease, and the capacity of the fungus and beetle to invade new areas.

These serious invaders can easily move on firewood from infested areas. Require those using your lands to follow these BMPs.

Best Management Practices for Firewood & Wood Products


Aquatic Plants and Animals

waterhyacinth
waterhyacinth
zebra mussels
zebra mussels

Invasive aquatic plants, used as water garden and aquarium decorations, aquarium fish, bait fish and fishing worms should never be dumped or “released” into any stream, lake, river or other water body. Invasive aquatic plants, can infest slow moving water such as ponds, lakes, swamps, irrigation canals, or ornamental ponds. Dense populations of invasive plants can clog waterways, which makes fishing, swimming and boating difficult. Thick colonies cover the surface of the water, preventing air from reaching it. This reduces the amount of oxygen in the water, which fish and other organisms need to survive. These dense mats of invasive aquatic vegetation can also prevent animals from getting to the water, and may crowd or shade out native plants, which other organisms depend upon for food or shelter.

Many invasive aquatic plants continue to be sold through aquarium and pond supply dealers, both online and in retail garden centers.

New introductions are probably the result of the improper disposal of ornamental pond plants or water, or when ponds adjacent to local water bodies overflow with winter rains.



Best Management Practices for Boat Cleaning

For those using lakes, ponds and streams follow these BMPs to limit introduction of aquatic invasives.

Drain

Clean

Boat motor with hydrilla  wrapped in the propeller
Boat motor with hydrilla wrapped in the propeller

Dry


Never Release Exotic Pets into the Wild

Captured python
Captured python

The greatest pathway by which non-native fish and wildlife species find their way into native habitats is through escape or release by pet owners. Burmese pythons, now established throughout south Florida and the Everglades, feed on native mammals and birds. Recent studies have found dramatic reductions in small mammal populations in Everglades National Park as python populations have increased. Nile monitor lizards in south Florida pose a threat to the Florida burrowing owl, which is a protected species. These are just a few of the many examples of non-native species that have escaped or been released from their owners.


Feral Hogs (Wild Pigs)

Damage by feral pigs
Damage by feral pigs
Feral sow and piglets
Feral sow and piglets

European wild boar, feral hogs, and crossbreeds of the two can be found in the wild. Feral hogs are domestic hogs that either escaped or were released for hunting. Within a few generations they develop the traits needed for survival in the wild.

Feral hogs continue to grow in numbers. Because of their destructive feeding habits and potential to spread disease, feral hogs are a substantial liability to agriculture; native wildlife and natural areas. However, these animals are also sought for recreational hunting and commercial harvest. Adult feral hogs can weigh from 110 to 770 lbs. Females can give birth to litters of 1 –12 piglets beginning at about 9 months of age. Life span in the wild is usually about 10 years, but feral hogs have been recorded living as long as 27 years. Feral hogs are indiscriminate omnivores which allows them to survive across a wide range of habitats, limited only by scarcity of water and severely cold temperatures. They are considered to be intelligent and can be very aggressive when threatened. Humans are the main predator of mature feral hogs.

Trapping and hunting are the main forms of control.


Online Resources

General Invasive Species Information

www.invasive.org

Firewood

www.dontmovefirewood.org

Forest Pest Information

www.forestpests.org

Invasive Species Mapping

www.eddmaps.org

A Field Guide for the Identification of Invasive Plants in Southern Forests

http://wiki.bugwood.org/Archive:IPSF

A Management Guide for Invasive Plants in Southern Forests

http://wiki.bugwood.org/Archive:MGIPSF

National Association of Exotic Pest Plant Councils

www.naeppc.org

Center for Invasive Plant Management

www.weedcenter.org

National Park Service Weeds Gone Wild

www.nps.gov/plants/alien

National Invasive Species Information Center

www.invasivespeciesinfo.gov

The National Invasive Species Council

www.invasivespecies.gov

USDA Forest Service Invasive Species Program

www.fs.fed.us/invasivespecies

U.S. Fish and Wildlife Service Invasive Species

www.fws.gov/invasives

Fire Management and Invasive Plants: A Handbook

www.fws.gov/invasives/pdfs/USFWS_FireMgtAndInvasivesPlants_A_Handbook.pdf

Fire Effects Information – Invasive Plants

www.fs.fed.us/database/feis/plants/weed/weedpage.html

Invasive Plant Responses to Silvicultural Practices in the South

www.invasive.org/silvicsforinvasives.pdf

A landowner’s Guide for Wild Pig Management – Practical Methods for Wild Pig Control

www.aces.edu/pubs/docs/A/ANR-1397/ANR-1397.pdf

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