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Some species adapt to climate change, others face extinction

a number of recent studies have shown that climate change has a significant impact on various species, especially birds. While some show behavioural changes, some undergo genetic changes over a period of time, and others face the threat of extinction. With a heavy pressure on habitat and food source, there are examples showing that species tend to partially adapt themselves as well.

A study published in the October issue of Global Change Biology (Vol 12, No 10) showed that 78 per cent of all leafing, flowering and fruiting activities advanced by 30 per cent and only 3 per cent got delayed.



On the brink The pied flycatcher (Ficedul hypoleuca), a migratory bird, is finding it difficult to forage for food. There has been a 90 per cent decline in its population, according to a paper published in the May 4 issue of Nature (Vol 441, No 7089).

Climate change is leading to disruption in the food chain because of change in timings of plant growth or animal life cycles. The food web of the Bering Sea is among them. The walleye pollock (Theragra chalcogramma), a forage species, has declined due to variations in atmospheric circulation through interactions with ocean currents.



"Animals are finely tuned to seasons and often rely for food on the availability of different plant species throughout the year. If the timing of plant activity shifts, animals are left without a food source,' says Elsa Cleland of the National Center for Ecological Analysis and Synthesis, us. She was part of the research on diverse responses of phenology (plant timings) to global warming and changes in grassland ecosystem.

According to estimates of the Audubon Society, a us-based conservation organisation, the population of the kittiwake, a seabird, is plunging because the fish they feed on have shifted location. In another instance, an off-season frost in Colorado is nipping life away from plants in many regions of the country, according to a University of Maryland paper published in Ecology Letters in October 2000. In the study, David Inouye, the lead author, found that the frost had led to a decline of squirrels by 17 per cent.

There are several other species which have been affected. Reduction in the area of sea ice formed near the Antarctic Peninsula has brought about a decline in the population of the krill, a key food source for predators like penguins, other sea birds, whales and seals. This is causing a heavy pressure on the diet of these animals. The Arctic tern no longer nests in Scotland because sand eel found in the North Sea on which the tern feeds, has been diminishing (see

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