The increase and geographic redistribution of IAS will have diverse societal and environmental impacts. Biological invasions are a major threat to global food security and livelihoods, with developing countries being the most susceptible. These countries, which have high levels of subsistence and smallholder farming, often lack the capacity to prevent and manage biological invasions.
IAS reduce the resilience of natural habitats, making them more vulnerable to the impacts of climate change. For example, some grasses and trees that have become IAS can significantly alter fire regimes, especially in areas that are becoming warmer and drier. This increases the frequency and severity of wildfires and puts habitats, urban areas and human life at risk. IAS can also impact agricultural systems, by reducing crop and animal health.
The economic costs of IAS and their management are in the billions of US$ annually, with invasive alien insects alone estimated to cost the global economy more than US$ 70 billion per year.
Biological invasions are among the top drivers of biodiversity loss and species extinctions across the world. A 2016 study published in the journal Biological Letters, showed that IAS are the second most common threat associated with species that have gone completely extinct since 1500.