Climate Change Dislocates Migratory Animals, Birds

NAIROBI, Kenya, November 17, 2006 (ENS) - Climate change is already having severe impacts on migratory species, from whales and dolphins to birds and turtles, and is likely to be increasingly disruptive, finds a new report by the United Nations Environment Programme, UNEP, released Thursday at the UN climate conference here.

Migratory species are in many ways more vulnerable that other species as they use multiple habitats and sites and a many difference resources during their migrations.

It is doubtful whether polar bears, Ursus maritimus, will be able to adapt fast enough to changing ice conditions affecting the habitat of their seal prey species, and the disappearance of the ice threatens the bears’ survival.


North Atlantic right whale breaches in Canadian waters. (Photo courtesy Bedford Institute of Oceanography)
The 300 remaining North Atlantic right whales may be impacted by a decline in their main food source, plankton, as a result of shifts in large ocean currents, says the study.

There is likely to be a general shift of species towards the poles, reducing the range of species most adapted to colder waters, the study finds.

The common dolphin, Delphinus delphis, a warm water species is increasing its range, while the cold water range of the white-beaked dolphin, Lagenorhynchus albirostris, is shrinking. Predators are following their prey as prey species of fish, change their latitude or depth in response to a warming climate.

UNEP Executive Director Achim Steiner said, "We need to bolster rather than clear habitats, reduce pollution to the land, freshwater and the marine environment, more sustainably manage water supplies for people and wildlife and enact other measures to assist animals and plants to cope and to adapt in a climatically changed world."

The report, by UNEP’s Convention on Migratory Species, CMS, was compiled with support from the UK Department of Environment, Food and Rural Affairs.

Close to one-fifth of the bird species listed under the Convention could be affected by rising sea levels, erosion and greater wave action linked with climate change, including the lesser white fronted goose.

The study says lower water tables and more frequent droughts will reduce habitat for the Baikal teal and foraging grounds for species like the aquatic warbler.


Penguins eat krill, fish, and squid, but some of the smaller penguins eat only krill. (Photo courtesy Guillaume Dargaud)
Small ocean animals called krill that form the base of the food chain may be outcompeted by other species more tolerant of warmer water. The study preducts repercussions for species higher up the food chain, including penguins, albatrosses, seals and cetaceans, despite their wide foraging ranges.

Animals and plants specialized to live in Arctic and Alpine environments will also face greater competition for food from other species which did not previously inhabit higher altitudes.

Governments have agreed to reduce the rate of loss of biodiversity by 2010, but Steiner says a warming planet is making that goal tough to attain.

"Biodiversity - a term for the range of animal, plant and other life on this planet - is already suffering from a range of impacts including overexploitation, loss and damage to habitats and pollution. Unchecked, climate change will pile on more pressure, making it increasingly difficult for the world to meet the 2010 target," Steiner said.

CMS Executive Secretary Robert Hepworth said, “The best form of adaptation is mitigation - in other words reducing greenhouse gas emissions by the 60 per cent to 80 per cent that is likely to be needed to stabilize the atmosphere. But we know that the world can no longer avoid some measure of climate change now and in the future, so we must act to help people and the wildlife, upon which many livelihoods depend, adapt."


The Bassin du Drugeon wetland in France. Wetlands can act as stopover sites for migratory waterbirds. (Photo by Tobias Salathé courtesy Ramsar)
Sigmar Gabriel, the German Environment Minister, whose country hosts the CMS, endorsed the report’s conclusions.

"Measures, such as maintaining a coherent network of stopover sites like wetlands; creating and expanding suitable habitat like field margins, hedgerows and ponds and developing and sustaining trans-boundary corridors that allow species to migrate as the climate changes, will be key to ensuring a healthy level of biodiversity now and in the future," Gabriel said.

The report, "Migratory Species and Climate Change: Impacts of a Changing Environment on Wild Animals," has documented a wide range of climate effects that are now occurring.

Changes in Migration Routes and Barriers to Migration

Changes in the length, timing and location of migration routes are being documented. In extreme cases, species have abandoned migration altogether. In other cases, species now migrate to areas where they have not been recorded other than as occasional vagrants.

Exotic southern fish species like the red mullet, anchovy, sardine and poor cod are now being found in the North Sea. Fish species are unable to regulate their body temperature, and their distribution and abundance are temperature dependent.

European bee-eaters, Merops apiaster, birds once very rare in Germany, are now breeding regularly across the country.

The rosy-breasted trumpeter finch, Rhodopechys githaginea, is one of many birds once normally confined to arid North Africa and the Middle East now found in increasingly large numbers in southern Spain.


Migratory Bewick swans in flight over the United Kingdom (Photo courtesy Wildfowl and Wetlands Trust)
The arrival of hundreds of Bewick swans, Cygnus columbianus, flying in distinctive “V” formations used to herald the arrival of the British winter. Ornithologists now report numbers down to double figures. Warmer weather on the continent and the absence of the northeast winds which aid their migration are the likely reasons for the swans’ non-appearance in their traditional British wintering sites.

Changing wind patterns are making it more difficult for passerine birds to make their migration in the Caribbean where spring storms are becoming more numerous and of greater intensity.

This autumn several large monarch butterflies, Danaus plexippus, which migrate in millions every year from the USA and Canada to Mexico, have been blown across the Atlantic to England 5,000 kilometers away.

Desertification is increasing the size of the Sahara Desert, and the report says the spreading desert will adversely affect the ability of Afro-European migrants to cross this ecological barrier successfully.

Habitat Changes

The permafrost is thawing and Arctic tundra is being replaced by forest, sea levels are rising, hurricanes are more frequent in the Caribbean, and in addition, Antarctic waters are getting warmer and the ice is melting, affecting sea salinity.

Alien species like the Pacific oyster, Crassostrea gigas, brought to Europe for commercial reasons, once were not able to survive outside artificial pens. As the North Sea has grown warmer, the Pacific oyster has been able to breed in the wild and is now displacing native oysters in the Wadden Sea.

Flooding and sediment runoff in Queensland, Australia damaged seagrass pasture leading to reduced growth and breeding rates for green turtles, Chelonia mydas,

Baffin Bay hosts the largest concentrations of wintering narwhals, Monodon monocerus. Here the trend has been for increased ice coverage in winter. The narwhals depend on cracks in the ice to breathe and there have been several occasions when they have become trapped in the ice. Their site fidelity and the decrease in open water make them susceptible to climate change.

The report, "Migratory Species and Climate Change: Impacts of a Changing Environment on Wild Animals" is online at:

The UN climate change conference concluded today with agreement on a workplan for future cuts in emissions of greenhouse gases and another agreement to help developing countries adapt to global warming. For the ENS report on outcomes of the conference, click here.