Environmental and Ecological Impacts

Native species in California's estuaries are expected to experience greater declines as invasive species interact with climate change, according to a study from the University of California, Davis. The study, published in the Ecological Society of America's journal, Ecology, said these declines are expected not only because of climate-related stressors, but also because of the expanding influence of new invasive predators whose impacts are occurring much farther up the estuary.

A new botanical survey of southwest Ohio found that invasive species introduced to the United States over the past century are crowding out many native plants. Biologists from the University of Cincinnati are retracing two exhaustive surveys conducted 100 years apart to see how the Queen City's plant diversity has changed over the past two centuries. They focused their attention on undeveloped parts of cemeteries, banks of the Mill Creek and public parks that have remained protected from development during the last 200 years. The study, titled "The rise of nonnative plants in wooded natural areas in southwestern Ohio," was published in June in the journal Ecological Restoration.

Scientists tallying the economic damage wrought by invasive pests across the world found two species are responsible for more harm than any other.

The American bullfrog and brown tree snake have collectively caused $16.3bn in global damage since 1986. In addition to ecological harm, the invasive pair have ruined farm crops and triggered costly power outages.

Invasive species cause biodiversity loss and about $120 billion in annual damages in the U.S. alone. Despite plentiful evidence showing that invasive species can change food webs, how invaders disrupt food webs and native species through time has remained unclear. Now, thanks to a collaborative study conducted by researchers representing the University of Montana's Flathead Lake Biological Station (FLBS), U.S. Geological Survey (USGS), and Montana Fish, Wildlife & Parks, there is new insight into how invasive species progressively affect native food webs.

IUCN has launched a global standard for classifying the severity and type of impacts caused by alien species, known as the Environmental Impact Classification for Alien Taxa (EICAT). This tool will alert scientists, conservation practitioners and policy makers to the potential consequences of invasive alien species, guiding the development of prevention and mitigation measures.