* Warmer world can give species an edge, disrupting nature
* Spread of more tolerant species threatens livelihoods
* Eradication, steps to control spread are key
By David Fogarty, Climate Change Correspondent, Asia
SINGAPORE, Oct 22 Climate change is set to
drive the spread of invasive plant and animals species,
threatening forests, fisheries and crops, in a double blow to
nature and livelihoods, a World Bank-funded report said on
The study by Nairobi-based Global Invasive Species Programme
says a warmer world, more extreme weather and higher levels of
planet-warming carbon dioxide will give some species an edge,
devasting ecosystems at sea and on land.
"The estimated damage from invasive species worldwide
totals more than $1.4 trillion annually -- 5 percent of the
global economy," says the report issued on the sidelines of a
major U.N. meeting in Japan aimed at combatting the destruction
The United Nations says climate change, pollution,
deforestation and over-hunting have led to a rapid rise in
extinctions, threatening the richness of nature that underpins
services such as clean air, water as well as food and health.
"Individually, climate change and invasive species present
two of the greatest threats to biodiversity and the provision
of valuable ecosystem services," says the report for
It outlines myriad examples of invasive plants and animals
that have proven much more adept at survival than other local
species, leading to erosion, damage to crops, livestock and
fisheries and lost income for tourism.
In particular, climate change can lead to some local
species becoming much less able to adapt to warmer temperatures
or more extreme droughts and floods, making them vulnerable to
other species that have much greater tolerance levels.
In some cases, invasive species can also curb the amount of
carbon dioxide that nature can soak up from the atmosphere.
In North America, warmer winter temperatures have led to an
explosion in the numbers of native mountain pine beetles,
killing off large areas of forest.
GREEN CRABS, LIONFISH
In the Caribbean, the lionfish, which is native to coral
reefs in the South Pacific, Indian Ocean and Red Sea, has
quickly spread since first released in the mid-1980s.
The fish is a voracious predator with venomous spines and
has no natural enemies in the Caribbean, threatening local
fish, shrimp and crab populations. Warming ocean temperatures
in the region have helped it thrive.
Along the west coast of the United States and Canada, the
European green crab is threatening native clam, mussel and crab
species and possibly arrived in ship ballast water.
Weeds, pests and diseases were also a growing threat to
agriculture, the study says, undermining food security.
"Indirectly, climate change will impact agriculture by
increasing the incidence and intensity of invasive species,"
says the report. Agriculture supports the livelihoods of more
than a third of the world's population.
The study also pointed to the likely spread of diseases
such as bird flu, plague, Rift Valley fever, dengue, ebola and
malaria. "Climate change combined with global trade and
transport networks may significantly increase the threat of
such pandemics," the authors say.
The study urged policymakers to take steps to halt the
spread of non-native species, develop early detection systems,
restore and protect existing ecosystems to make them more
resilient and eradicate or control species that limit nature's
ability to soak up carbon.
(Editing by Miral Fahmy)