Sheep go down because of the greenhouse effect

A 20-year study in Scottish sheep shows that climate change is altering their body size and population size. Cold winters create big sheep, but in the winter it is not too cold, this effect disappears.

"Until now, scientists have not been able to prove how each other's ecosystems interact and evolution, but we have found a way to link them together , " Tim Coulson, scientist at Imperial University (London, England), said.

Dr. Coulson and colleagues investigated this by tracking Soay sheep on Hirta island in the Outer Hebrides archipelago."We study these sheep because of the environment in which they live like a natural laboratory. On that island there are only sheep and grass - a really simple ecosystem," Coulson explained.

(Photo: BBC) Scientists analyze the population size and sheep body measurements based on data recorded since 1985. "To know how ecosystems affect the process. evolution and vice versa, we need to find out if the body characteristics are partially controlled by genes such as size, eye color, which affect the size of the population. "

The researchers found that body size is related to the number of sheep : When many large sheep appear on the island, the number of individuals tends to fluctuate with a fairly wide range, possibly Due to body size determines the likelihood of success in reproduction. But experts also found that sheep's body size was dominated by the environment.

"The severity of winter in Scotland is constantly changing throughout the study , " Coulson said. "In extremely cold winters in the 1980s, data show that large numbers of sheep account for a high percentage of the island. But in the next few years, winters are getting warmer, we realize that those with big size is no longer as dominant as before; even that is an unfavorable factor. "

According to Coulson, this study shows how environmental factors govern ecological and evolutionary changes, and predicts that due to climate change, and winters become less severe, Sheep may be getting smaller and their numbers will be more stable.

"Many people think that climate change will leave ecological consequences, but we have shown that it will also leave a legacy for the evolution of animals , " he said.

Hoang Long