Invasives

Invasives, or invasive species, are non-native organisms that spread beyond their original range and cause ecological, economic, or health impacts in new environments. Not all introduced species become invasive; invasiveness depends on the organism’s traits and the conditions of the recipient ecosystem, including the presence of natural enemies, resource availability, and disturbance.

Common pathways include ballast water, international trade, ornamental plant escapes, pet releases, and agricultural introductions. Once established, invasive species can colonize multiple habitats and reproduce rapidly, often outcompeting native species for food and space.

Impacts include biodiversity loss and altered ecosystem processes, such as fire regimes and nutrient cycling. Economic costs affect agriculture, forestry, fisheries, and infrastructure. Notable examples include zebra mussel in North America, Asian carp, kudzu, Japanese knotweed, and the cane toad in Australia.

Management emphasizes prevention and rapid response. Measures include monitoring, early detection, removal, habitat restoration, targeted chemical controls, and, when appropriate, carefully assessed biological control. Policies often involve quarantine, ballast water regulations, public education, and collaboration across agencies and landowners.

Challenges include climate change-driven range shifts, uncertainties in risk assessment, and potential unintended effects of control methods. Effective management relies on data sharing, stakeholder participation, and integrating ecological knowledge with social and economic considerations.