World losing high-stakes fight against alien species

Invasive species that wreck crops, ravage forests, spread disease, and upend ecosystems are spreading across the globe faster than was previously thought.

The water hyacinth is an invasive plant native to many countries, including South America's Amazon basin. AFP

The failure is costing well over $400 billion dollars a year in damages and lost income. The rate of spread is also likely to be a "gross underestimation" than even current estimates, according to the intergovernmental science advisory panel for the UN Convention on Biodiversity (IPBES).

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From water hyacinth choking Lake Victoria in East Africa, to rats and brown snakes wiping out bird species in the Pacific, to mosquitoes exposing new regions to Zika, yellow fever, dengue and other diseases, the report catalogued more than 37,000 so-called alien species that have taken root, far from their places of origin.

That number is trending sharply upward, along with the bill for the damage, which the report estimates, is multiplying fourfold per decade, on average, since 1970.

Economic expansion, population increase and climate change "will increase the frequency and extent of biological invasions and the impacts of invasive alien species," the report concluded.

Only 17 percent of countries have laws or regulations to manage this onslaught.

Whether by accident or on purpose, when non-native species wind up on the other side of the world, humans are to blame.

Invasive Species have HUGE impacts © ipbes

Human actions

Scientists point to the pervasive spread of these species as hard evidence that the rapid expansion of human activity has radically altered natural systems so much that it has tipped Earth into a new geological epoch called the Anthropocene, or the "era of humans".

The hyacinth that at one point covered 90 percent of Lake Victoria is thought to have been introduced by Belgian colonial officials in Rwanda as an ornamental garden flower before making its way down the Kagera River in the 1980s.

The Florida Everglades is teeming with the destructive offspring of erstwhile pets and houseplants, including five-metre (16-foot) Burmese pythons and walking catfish an Old World climbing fern and Brazilian pepper.

In the same way, rabbits were brought to New Zealand in the 19th century by English settlers to hunt and for food, before they multiplied, forcing officials to import stoats to reduce their numbers. These too, in turn, multiplied and spread.

New Zealand and Australia have become "case studies" of how not to control one imported pest with another, according to Elaine Murphy, a scientist at New Zealand's Department of Conservation

Invasive species are also often accidental arrivals, via cargo ships, containers or tourists' suitcases.

The Mediterranean Sea is full of non-native fish and plants, such as lionfish and killer alga, which journeyed from the Red Sea through the Suez Canal.

  (with newswires)