Up to 900 tropical bird species could 'go extinct'

Up to 900 species of tropical land birds around the world could become extinct by 2100, researchers say.

The finding is modelled on the effects of a 3.5C Earth surface temperature rise, a Biological Conservation Journal paper shows.

Species may struggle to adapt to habitat loss and extreme weather events, author Cagan Sekercioglu says.

Mountain, coastal, restricted-range, and species unable to get to higher elevations could be the worst affected.

 

Birds at risk:

          

• Some tropical mountain birds such as Venezuela's scissor-tailedhummingbird and East Africa's regal sunbird are endemic to theirhabitats and have limited capacity to move, which could make thesespecies especially vulnerable.
• Loss of land due to rising sea levels is one of the threatsfaced by tropical island species. The mangrove finch on the GalapagosIslands, the Abbott's booby on Christmas Island and Mexico's Cozumelthrasher are at risk.
• Hundreds of restricted-range species could be under threat,including the horned guan, the Cochabamba mountain-finch, thered-fronted parrotlet and the blue-eyed ground-dove.
• Physiological responses to climate change may play a vital rolein survival. Open habitat sunbirds in Uganda, like the scarlet-chestedsunbird, have a greater ability to tolerate fluctuating temperaturesthan forest sunbirds.

Depending on future habitat loss,

each degree of surface warming could affect between 100-500 species,

says Mr Sekercioglu, assistant professor of biology at the University of

Utah.

"This gives us a clear big picture. The problem is most

species in the world are highly sedentary... the public perception is

most birds are migratory and so climate change is not a problem for

them," he says.

Mr Sekercioglu says tropical mountain species are among the

most vulnerable. He says bird species will need to be able to adapt

physiologically to changes in temperature and be able to move to higher

altitudes if they are to survive.

He says cooler, more humid forests could recede higher up

mountains and combined with human settlements at higher altitudes,

forest habitat could "get pushed off the mountain".

This would create "an escalator to extinction" he says.

"Coastal species are also vulnerable - as coastal forest can

be sensitive to salinity, and these forests can get hit harder by

hurricanes and typhoons, and these events are also expected to

increase."

Birds in extensive lowland forests with few mountains in

places such as the Amazon and Congo basins - may have trouble

relocating, while tropical birds in open habitats such as savanna,

grasslands, scrub and desert face shrinking habitats.

Tropical birds in arid zones are assumed to be resilient to hot, dry conditions, but they could suffer if water sources dry out.

Mike Crosby, senior conservation officer in Asia at Birdlife

International says: "We know that quite a lot of tropical birds are not

very good at dispersing so this could be a big issue in the future if

the suitable climate moves several hundred kilometres or even tens of

kilometres, some of the birds might not be able to move their ranges

sufficiently quickly in response to that.

"We might have to take novel conservation measures in the future such as translocation of birds from one site to another."

 

More about manakins:

          

• There are around 45 species of manakins (Pipridae). They are found almost exclusively in tropical forests.
• Male club-winged manakins vibrate their wing feathers to create a sustained tonal sound to impress females.
• Manakins are polygynousbirds. Male manakins spend most of their time at leks (groups of malesgathering for mating displays), which females visit to choose mates.
• Male manakins are known for their elaborate courtship displays where they show off their bright plumages.

• Watch a manakin courting disaster

The study looked at how manakins,

of which there are 45 species in the neotropical region, would cope.

Results showed that manakins limited to the lowland habitats of the

Amazon and Cerrado in Brazil, would be most affected as they could lose

up to 80% of their habitat; as many as 20% of the Cerrado manakin

species are expected to go extinct.

Cagan Sekercioglu says: "Manakins show the importance of

having a wide tropical area of mid-elevation forests, and being able to

move to higher elevation forests."

He says while overall "birds are one of the least threatened

groups of animals" by climate change, "they are the 'best case'

scenario".

"The findings are likely to be much worse for all other groups of animals," he says.

"We need to be planning protected areas with higher

elevations in mind and leave breathing room for endangered species in

higher elevation areas," says Mr Sekercioglu.

Mr Crosby says: "We've got to prepare ourselves to be

measuring temperature in protected areas, and measuring rainfall, and

monitoring what's happening to species, so that we can respond in the

appropriate way. It's very difficult to predict very precisely what's

going to happen."

He adds that visitors to the region could help protect the birds they travel to see.

"People who go bird watching in the tropics can gather very

useful data, given that the current data that we have is basically

pretty poor in many parts of the world. Amateur bird watchers can really

make an important contribution."