A careful reconstruction of a 3-year study of birds on a mountain course in Peru has given researchers a rare…
A careful reconstruction of a 3-year study of birds on a mountain course in Peru has given researchers a rare chance to prove how the changing climate drives species out of the places they are best adapted to.  Surveys of more than 400 bird species in 1985 and since 2017 have found that the population of almost all had decreased, as many as eight had disappeared completely and almost all had moved to higher heights in what researchers call “an escalator of extinction”  “As you move as far as you can go, there is nowhere else left,” says John W Fitzpatrick, one of the study’s writers and director of the Cornell Laboratory of Ornithology.
“On this mountain, some ridged bird populations were literally wiped out.”
It is not certain whether the birds shifted varies due to temperature changes or indirect effects, such as shifts in insects or seeds that they breed.
The study find, published in Proceedings of the National Academy of Sciences confirms which biologists have been suspected for a long time but had few opportunities to confirm.
] The existence of an 1985 survey of birds on the same mountain gave researchers a rare and useful baseline.
Previous research has documented habitats of birds and other species that rise in height or width in response to heating temperatures. But Mark Urban, director of the Center for Biological Risk at the University of Connecticut, who was not involved in the study said.
“A study like this where you have historical data you can go back to and compare is very rare,” said Urban. “As long as the species can spread, you’ll see species marching up the mountain until the escalator becomes a staircase to the sky.”
1985, Fitzpatrick built a base camp beside a river running down a hillside in southeast Peru, aiming to catalog the habitats of tropical bird species that lived there. His team spent several weeks walking up and down Cerro de Pantiacolla, using nice networks called rail networks to catch and drop birds and keep detailed magazines of birds they caught, dotted or heard nudging in the woods.
Two years ago, Fitzpatrick sent his magazines, pictures and other documents to Benjamin Freeman, a postdoctor at the Biodiversity Research Center at the University of British Columbia. Freeman, who has researched tropical birds for more than a decade, decided to recreate the trip in August and September 2017. With his old pictures of mountain views his team was in the same base match.
Freeman largely reflected Fitzpatrick’s road and methodology to see what had happened in the next few years, a period when average mean temperatures on the mountain increased 0.76 degrees Fahrenheit (0.42 degrees Celsius). Because the mountain is at the edge of a national park, the area had not been disturbed.
In addition to unfurling 40 meter (12 meter) rail networks on the slopes, Freeman team placed 20 microphone boxes on the mountain to record birds that can not be easily seen.
“We found that the bird communities move up the slope to reach the climate conditions they were originally adapted to,” said Freeman, leading author of the study
Near the top of the mountain, the birds moved higher at 321 feet (98 meters ).
“We think the temperature is the main switch to explain why species live where they do mountain hills,” Sade Freeman. “A large majority of species in our study did the same thing.”
Birds adapted to live in narrow temperature bands – in regions without major seasonal variations – may be particularly vulnerable to climate change, said Fitzpatrick. “We should expect what happens on this mountain peak to happen more generally in Andes and other tropical mountain ranges,” he said.