Invasive species are non-native organisms that spread rapidly in new environments, often causing harm. They can be plants, animals, or microorganisms introduced by human activity. Invasive species disrupt ecosystems, outcompeting native species for resources. This competition can lead to the decline or extinction of native species. Invasive species often lack natural predators in their new habitats, allowing them to multiply unchecked. They can alter habitats by changing soil composition, water availability, or other environmental conditions. Some invasive plants release chemicals that inhibit the growth of native species.

Humans play a significant role in spreading invasive species, often through global trade and travel. Ships, for example, can transport invasive species in their ballast water. Invasive species can hitchhike on cargo, vehicles, and even clothing. Climate change may exacerbate the problem by creating conditions more favorable for invasive species. The economic impact of invasive species is substantial, costing billions annually in control efforts and damage. Agriculture is particularly vulnerable, as invasive pests can devastate crops. The zebra mussel, an invasive species in North America, clogs water pipes and damages infrastructure.

Invasive species can also harm human health by spreading diseases. The mosquito species Aedes aegypti, which is invasive in many parts of the world, transmits diseases like dengue and Zika. Some invasive species reduce biodiversity, weakening the resilience of ecosystems. Invasive plants, such as kudzu in the United States, can smother trees and other vegetation. The introduction of invasive species often has unintended and far-reaching consequences. Invasive species are a major threat to conservation efforts and biodiversity worldwide. Some ecosystems, like islands, are particularly vulnerable to invasive species because of their isolation.

Efforts to control invasive species include physical removal, chemical treatments, and biological control. Biological control involves introducing a predator or pathogen to reduce the population of the invasive species. However, biological control can sometimes have unintended negative effects on native species. Prevention is generally more effective and less costly than trying to eradicate an invasive species once it’s established. Public awareness and education are key to preventing the spread of invasive species. Governments and organizations worldwide are working to create policies that reduce the risk of invasions. Early detection and rapid response are critical to managing new invasions before they become uncontrollable.

Invasive species can thrive in disturbed environments, such as areas affected by deforestation or urbanization. Some invasive species, like feral cats, prey on endangered wildlife, exacerbating the decline of these species. Invasive species can also affect freshwater systems by altering the food web and water quality. Certain invasive species are intentionally introduced, such as ornamental plants, which later escape into the wild. The spread of invasive species is one of the leading causes of habitat destruction globally. Efforts to combat invasive species must be coordinated across borders, as species do not respect political boundaries.

Rehabilitation of ecosystems damaged by invasive species can take decades or even centuries. Invasive species like the European starling in North America have changed the composition of bird communities. Some invasive species are incredibly adaptable, able to survive in a wide range of conditions. Not all non-native species become invasive; only those that cause harm are classified as invasive. Invasive species management requires ongoing monitoring and research to adapt to new challenges.