February 19, 2014
Genetic Diversity Of The European Beaver In Peril Due To Human Predation
Brett Smith for redOrbit.com - Your Universe Online
Long-prized for their thick fur, the cuddly Eurasian beaver has been hunted by humans for thousands of years and a new genetic study from a large group of international researchers has found that predation by humans has significantly cut down the genetic diversity of these animals.“While beaver populations have been growing rapidly since the late 19th century when conservation efforts began, genetic diversity within modern beaver populations remains considerably reduced to what was present prior to the period of human hunting and habitat reduction,” said study author Michi Hofreiter, a biology professor from the University of York in the United Kingdom.
In the study, which was published in the journal Molecular Ecology, the research team found that the Eurasian beaver can be divided into three different groups. The two predominant ones are in western and Eastern Europe and a now extinct, and previously unknown, third group inhabiting the Danube river basin. This population was around at least 6,000 years ago but vanished during the transition to modern society.
“The rapid loss of diversity prior to conservation efforts appears to have established a very strong pattern for the geographic distribution of genetic diversity among present-day beaver populations,” Hofreiter said.
After centuries of being hunted by humans, the Eurasian beaver had faded from the majority of its original range at the end of the 1800s, with approximately 1,200 beavers remaining. The researchers said they wanted to see if the lack of genetic diversity and strong distribution of genetic diversity seen today are caused by hunting or had already existed before the beavers’ range was diminished.
To reach their conclusion, the team analyzed DNA from 48 ancient beaver samples, ranging in age from a few hundred to about 11,000 years old, and over 150 modern beavers. The analytical work was performed at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
“We found that overall there was more genetic diversity in the past,” said study author Susanne Horn, from the institute. “Apparently, already in ancient times an ancient contact zone existed between the eastern and western populations of beavers in the Oder River area. This is close to a present-day contact zone in Germany and Poland.”
“The present-day contact zone was assisted by conservation management and members of the eastern and western population groups meet there today as they did in the past,” Hofreiter said. “This suggests that conservation management may, in the long run, help to restore the pre-human impact population structure of threatened species.”
Beavers have long been an essential resource for humans living in northern continents around the world. Their fur is considered to be exceptional and has been a highly-traded item for centuries. Beavers have also been hunted for meat and for castoreum – an anal gland secretion used in traditional folk medicine. Stone carvings at Lake Onega in northern Europe reveal that beavers played a major role in ancient human communities between 3,000 and 4,000 years ago.