Impacts of Exotic Species

In the United States, exotic species were introduced deliberately (for ornamental, aesthetic, medicinal, or agricultural reasons by humans) or accidentally (through animal vectors, ballast water discharge, movement of people, or by trading of nursery stock). Today, invasive species are posing a major threat to humans and to terrestrial and aquatic ecosystems. According to recent statistics by researchers and conservation experts, it is estimated that invasive species infestations cover nearly 100 million acres in the United States. These species cost the U.S. economy more than $138 billion dollars per year in damages and control efforts.

Some of the impacts of exotic species include:

Loss of Biodiversity
Soil erosion or disturbance
Habitat loss
Alteration of soil moisture and salinity levels
Alteration of nutrient levels in soil
Increase in fire frequency and intensity
Hybridization with native species
Alteration of food chains

How exotics cause problems: Removing a species from its native environment frees it from natural predators, parasites, pathogens and competitors that limit its numbers. Therefore, an exotic species is often capable of explosive population growth. In many instances, exotic species become pests by out-competing or preying upon endemic species. Hawaii, Florida and California have experienced major ecological problems with exotic plants and animals that have been introduced by humans.

Learn more about the impacts of exotic species by looking at some examples

or choose another topic to explore:

What is an exotic species?
How are exotic species introduced?
Basic ecology