The Invasive Exotic Dilemma
Many exotic introduced plants have become naturalized in North Carolina and some are replacing our native plant species.
Not all exotic species are considered harmful.
Invasive plants are usually characterized by:
- fast growth rates,
- high fruit production,
- rapid vegetative spread,
- and efficient seed dispersal and germination.
Not being native to NC, they lack the natural predators and diseases which would naturally control them in their native habitats.
The rapid growth and reproduction of invasive plants allows them to overwhelm and displace existing vegetation and, in some cases, form dense one-species stands.
Invasive species are especially problematic in areas that have been disturbed by human activities such as road building, residential development, forest clearing, logging, grazing, mining, ditching, mowing, erosion control, and fire control activities.
Invasive exotic plants disrupt the ecology of natural ecosystems, displace native plant and animal species, and degrade our biological resources. Aggressive invaders reduce the amount of light, water, nutrients and space available to native species.
Some cause increased erosion along stream banks, shorelines and roadsides.
Some exotics hybridize with related native plant species, resulting in changes to a population's genetic makeup; others have been found to harbor plant pathogens that can affect both native and non-native plants, including ornamentals. Others contain toxins that may be lethal humans and other animals.
Some invasive plants compete with and replace rare and endangered species and encroach upon their limited habitat.
Other problems include disruption of native plant-pollinator relationships, tree and shrub mortality due to girdling, reduced establishment of native tree and shrub seedlings, reduction in the amount of space, water, sunlight and nutrients that would be available to native species, and altered fire regimes.
Invasive plants also cause economic losses and expenditures each year for agriculture, forestry, and roadside management.
Our native fauna, including insects, birds, mammals, reptiles, fish and other animals, is dependent on native plants for food and shelter.
While some animals can feed on a wide number of plant species, others are highly specialized and may be restricted to feeding on several or a single plant species.
As exotic plants replace our native flora, fewer host plants are available to provide the necessary nutrition for our native wildlife.
In some cases, invasive plants replace nutritious native plant foods with lower quality sources.
Each exotic plant is one less native host plant for our native insects, vertebrates and other organisms that are dependent upon them.
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