Competition for Resources: Non-native species can compete with native species for limited resources such as food, water, and habitat. When non-native species are successful competitors, they can reduce the abundance and diversity of native species. This competition can lead to the decline or even extinction of native species.
Predation and Disease Transmission: Some non-native species are voracious predators or carriers of diseases that can harm native species. For example, the introduction of the Burmese python to the Florida Everglades has decimated native prey populations and disrupted the food web. Similarly, diseases like chestnut blight, caused by an introduced fungus, have devastated American chestnut trees.
Habitat Modification and Disruption: Non-native species can cause drastic changes to their new environments, often with detrimental effects. Some plants, such as kudzu in the southeastern United States, can grow rapidly and form dense mats that block sunlight from reaching native plants, disrupting natural ecosystems. Others, like the zebra mussel, can modify aquatic habitats by clogging pipes and altering water quality, impacting native species.
Hybridization and Genetic Introgression: Non-native species can interbreed with closely related native species, resulting in hybrid offspring. This can lead to genetic introgression, where genes from the non-native species are introduced into the native population, potentially diluting the genetic integrity and distinctiveness of the native species.
Economic and Human Health Impacts: Invasive species can also cause significant economic losses. For instance, the emerald ash borer has decimated ash trees in North America, leading to billions of dollars in losses to forestry and landscaping industries. Additionally, some non-native species can pose health risks to humans, such as the transmission of West Nile virus by invasive mosquitoes.
Overall, non-native species can disrupt ecosystems, reduce biodiversity, and cause economic and health problems. Preventing their introduction and managing their populations are essential for preserving the integrity of native ecosystems and safeguarding human well-being.