[font face=Serif]PUBLIC RELEASE DATE: 16-Dec-2014

Contact: Joan Robinson
joan.robinson@springer.com
49-622-148-78130
Springer

[font size=5]Damming beavers are slowly changing the world[/font]

[font size=4]Study shows the effect that growing beaver population is having on habitat and methane gas emissions[/font]

[font size=3]There are consequences of the successful efforts worldwide to save beavers from extinction. Along with the strong increase in their population over the past 100 years, these furry aquatic rodents have built many more ponds, establishing vital aquatic habitat. In doing so, however, they have created conditions for climate changing methane gas to be generated in this shallow standing water, and the gas is subsequently released into the atmosphere. In fact, 200 times more of this greenhouse gas is released from beaver ponds today than was the case around the year 1900, estimates Colin J. Whitfield of the University of Saskatchewan in Canada. He led a study¹ in Springer's journal AMBIO² about the effect that the growth in beaver numbers in Eurasia and the Americas could be having on methane emissions.

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Whitfield's team found that global beaver numbers have grown dramatically, to a population of over 10 million. The Eurasian population could grow by an additional four million. In the process of population recovery, beavers have dammed up in excess of 42,000 square kilometres of aquatic pond areas, which are bordered with over 200,000 kilometres of shoreline habitat.

Parallel to the increase in beaver populations is also a notable increase in methane emissions because of their pond-building efforts. At the end of the 20th century, beaver activities contributed up to 0.80 teragrams (or 800 million kilograms) of methane to the atmosphere each year. This is about 15 percent of what wild cud-chewing animals, such as deer or antelope, contributed.

"The dynamic nature of beaver-mediated methane emissions in recent years may portend the potential for future changes in this component of the global methane budget. Continued range expansion, coupled with changes in population and pond densities, may dramatically increase the amount of water impounded by the beaver," says Whitfield. "This, in combination with anticipated increases in surface water temperatures, and likely effects on rates of methanogenesis, suggests that the contribution of beaver activity to global methane emissions may continue to grow."

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