Only a very small subset of species introduced to an area where they are not native will become invasive. But when the invasion begins, it can be costly. The best way to fight an invasion is to prevent one from happening.
The Spread of Invasives
Each invasive plant has its own strategy for growth and dispersal. Some have seeds that are spread by the wind, such as pampas grass, whose seeds can be blown up to two miles away. Others have seeds that are carried by water or eaten by birds and animals that deposit them far from the parent plant. There are also species that reproduce vegetatively, such as Johnson grass, which spreads from seeds and underground rhizomes.
Some exotic animals, such as hogs, may only become problems over an extended period of time. Hogs were first introduced to North America by European explorers in the 16th century for food, but feral populations are now found in all areas of Arkansas, most densely in the bottomland hardwood forests of the south. Since 2000, the number of Arkansas Wildlife Management Areas with feral hogs has more than doubled.
Costs Accrue over Time
When an aggressive plant or animal is introduced into a new environment, the predators, pathogens, and competitors that would normally limit their growth are unlikely to be present.
This allows them to proliferate, spread, and take over natural habitats. Invasive species are a leading threat to biodiversity, second only to habitat destruction. The economic cost is as significant as the ecological cost: in Arkansas, millions of dollars of agricultural damage each year comes from feral hogs alone. Invasive plants damage agriculture by reducing crop and livestock production or threatening export potential, with impacts on U.S. prices, consumers, and trade.
Costs of managing alien plants include costs of education, early detection, eradication and ongoing control. As international trade is potentially a key conduit of movement between countries, the presence of certain pests in the United States could cause some countries to stop importing U.S. products or require the goods to undergo special inspections, treatments, or mitigation programs before entry. In addition, U.S. producers, other businesses, APHIS, and State governments incur costs to prevent or reduce such losses. You can help stop the invasion! Refrain from planting and use early control methods at the first sign of Arkansas’s “top 10 invasive species of concern:"
- cogongrass (Imperatica cylindrica)
- tropical soda apple ((Solanum viarum)
- Sudden Oak Death or SOD (caused by Phytophthora ramorum, a fungus like microorganism)
- Bacterial leaf streak of rice ( a disease)
- Hydrellia wirthi - a fly that attacks rice seedlings
- Hydrilla hydrilla - an aquatic weed
- Sirex wood wasp (Sirex noctilio)
- Old world Bollworm, Helicoverpa armigera
- Channeled Apple Snail (Pomacea canaliculata)
- Rice Nematode (D. angustus )
Appealing as some may be, the plants listed above are all notorious for escaping and invading outlying areas.
- Use nursery raised native plants. Ask your local nursery staff for suggestions or check out native gardening books from your local library or bookstore.
- Remove the 10 worst weeds from your property. If needed, contact your county Extension agent for recommended methods of chemical control. Use herbicides carefully. Many herbicides are not selective and will kill all surrounding vegetation or may harm aquatic systems.
- Contact your local USDA Service Center to see if any of these invasive species are eligible for cost-share assistance through such conservation programs as the Environmental Quality Incentives Program.
- Help control exotic plants on nearby public lands. This can be an educational and productive activity for scouts, 4H clubs and other service groups. Check with your local highway department, forest, refuge or park for exotic plant removal projects.