Over the past two centuries, the global movement of plants, animals, and insects beyond their native ranges has accelerated, driven largely by trade and colonization. Originally introduced for various purposes—including ornamental gardening, agriculture, and aquaculture—many of these non-native species have since become invasive, disrupting ecosystems worldwide.

A 2023 global assessment conducted by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) identified more than 3,500 invasive alien species that pose significant threats to biodiversity and environmental health. These species outcompete native flora and fauna, alter habitats, impact water and soil chemistry, and damage agriculture and infrastructure. The economic costs linked to controlling invasive species are substantial. In the United Kingdom, legal cases have resulted in damages being awarded after sellers failed to disclose the presence of a particularly aggressive Japanese weed to homebuyers.

Invasive species are implicated in approximately 60% of documented global extinctions, according to the IPBES report. Despite this, the continued introduction of new species persists due to gaps in enforcement and regulatory frameworks. KV Sankaran, former director of the Kerala Forest Research Institute and coordinating lead author of the IPBES report, highlighted the case of the Indian bullfrog, which was introduced to the Andaman Islands in the 2010s during fish farm development efforts. The bullfrog has since become a significant threat to native amphibians, fish, and small reptiles in the region.

Beyond the direct loss of species, invasive organisms can act as ecosystem engineers, fundamentally reshaping their environments. Helen Roy, lead author of the IPBES assessment and professor at the University of Exeter, explained that invasive species can affect processes such as pollination, decomposition, oxygen levels in aquatic systems, and food availability, thereby altering entire ecosystems.

Efforts to mitigate the impacts of invasive species have often been reactive rather than preventive, with financial resources largely directed toward damage control rather than proactive management. Alok Bang, an ecologist and evolutionary biologist at Azim Premji University, noted that in countries like India, the lack of comprehensive data on the impacts of invasive species hampers policy action and public awareness.

Experts agree that prevention is more effective than management after establishment. The implementation of risk analysis, early detection, rapid response strategies, and stricter biosecurity measures are crucial. Australia and New Zealand have adopted a “whitelist” approach to biosecurity, permitting only species that have undergone thorough risk assessments to enter. Sankaran emphasized that this model reduces the chances of introducing unknown invasive threats compared to traditional “blacklists,” which exclude only known harmful species.

Public participation also plays a role, with responsible gardening, pet ownership, and consumer choices contributing to reducing the spread of invasive organisms. The longstanding global presence of the mosquito Aedes aegypti, native to parts of Africa and South America but now pervasive worldwide, illustrates the potentially severe human health consequences of invasive species. This mosquito species transmits diseases such as dengue, yellow fever, chikungunya, and Zika virus, causing tens of thousands of deaths annually and prompting massive investments in disease control.

Chilean ecologist Aníbal Pauchard of the Universidad de Concepción highlighted that the gradual, often unnoticed impacts of invasive species represent a significant but underappreciated ecological burden. Experts stress that the available evidence is sufficient to warrant immediate action to prevent further ecological damage, even as ongoing research continues to refine understanding and management approaches.