Tue, Aug 23, 2011 - Page 2 News List

Global warming forcing birds to migrate: scientists

By Tang Chia-ling  /  Staff Reporter

Bird habitats are being affected by global warming, with birds moving into colder, higher altitudes, a National Taiwan University expert said.

A research team headed by Institute of Ecological and Evolutionary Biology director Lee Pei-fen (李培芬) has demonstrated that birds are adapting to global warming and have begun building their nests at higher altitudes.

Conducting research at Yushan (玉山), 3,000km above sea level, Lee and his team discovered that the nesting grounds of the 13 types of birds dwelling between 2,100m and 3,700m above sea level climbed an average of 42.9m between 1992 and 2006.

The area of distribution also rose 33.7m during that same period, Lee said.

The area of distribution for white browed bush robins saw a significant increase, Lee said, adding that the robins’ area of distribution went from 3,182m to 3,454m, a rise of 272m.

The streak-throated fulvetta’s area of distribution went from 3,258m to 3,401m, a rise of 143m, he said.

The migration of middling altitude birds into higher altitude areas would compress the living area, foraging and food resources available to birds originally at higher altitudes, the research team found, adding that migrating outsiders are usually more forceful so the new arrivals could displace the original inhabitants or become dominant.

The new migrants have caused the population of the Formosan laughing thrush and four other species to fall, with the laughing thrushs’ area of distribution decreasing by 9m.

However, birds are not the only living things affected by global warming, said Allen Chen (陳昭倫), an associate research fellow at the Biodiversity Research Center at Academia Sinica, noting that corals were also “migrating.”

Coral bleaching is suspected to be the result of greenhouse gas by-products, such as rising sea temperatures and levels, and pH changes from ocean acidification.

Chen said that Asian records place the Pavona Cactus coral, which is found along the northern latitude, 25o off Taiwan’s Yehliu (野柳) and Bitou Cape (鼻頭角) as far as the Ryukyu Islands, which are on the same latitude as Yehliu.

However, during a Japanese survey in 2000, Pavona Cactus coral was found in the Wakayamal region in Japan, along the 35th northern latitude, Chen said.

Corals also moved to a higher altitude to survive, Chen said.

Chou Chang-hung (周昌弘), an Academia Sinica specialist in plant ecology and -phytochemical ecology, said plants are migrating as well because of global warming.

Chou said the area of distribution of Bigseed Swertia, a herb used in traditional Chinese medicine, moved higher by 800m from 1909 to 1991, and the area of distribution of the herb Diversifolious Hemiphragma moved down 249m from 1970 to 1999.

Plant seeds are scattered by the wind and are therefore more complex in their ecological makeup, Chou said, adding that the move to lower altitudes could not be definitely categorized as a result of global warming, though seeds are tending to go for higher altitudes because of global warming.

More worryingly, plants at the highest altitudes have nowhere to go and could become extinct, Chou said.


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