For years, officials in the Czech Republic had pushed a dam project to protect a river south of Prague, and the critically endangered species living in it.The project was drafted in 2018 and had a building permit, but had been delayed for years by negotiations over the land.
Officials had hoped to build a barrier to protect the river and its population of critically endangered crayfish from sediment and acidic water spilling over from two nearby ponds, Agence France-Presse (A.F.P.) reported.
In the meantime, a group of chisel-toothed mammals — renowned for their engineering skills and work ethic — decided to take on the task.The beavers of Prague simply built dams themselves.
The rodents' fast work saved the local authorities some 1.2 million euros, according to the Nature Conservation Agency of the Czech Republic.
"Nature took its course," Bohumil Fišer, the head of the Brdy Protected Landscape Area, where the revitalization project was planned, said in the statement.The beavers, he added, had created the ideal environmental conditions "practically overnight."
The beavers began working before the excavators could even break ground.It was not immediately clear specifically when the dams were built and how long it took to build them.
The new wetland created by the dams covers nearly five acres, the conservation group said.It is twice as large as the area that the humans had planned, A.F.P. reported.
Despite their remarkable ability to construct dams, beavers often draw the ire of landowners and farmers for destroying trees, eating crops and flooding roads and fields.
But in thinning a tree canopy, the rodents can often help to diversify an ecosystem by allowing sunlight in so that other plant species can thrive, said Emily Fairfax, an assistant professor of ecology at the University of Minnesota.
To build a dam, the beavers, whose weight as adults can range from about 40 to 80 pounds, begin by piling small stones across a river or stream, packing those stones in with mud, and repeating the process to construct a pond, which they then expand to become a wetland, Dr. Fairfax said.
They are motivated by their fear of predators: Beavers are adept swimmers and can hold their breath underwater for 15 minutes.On land, their ungainly waddle makes them easy prey.
The Czech dam is not the first time the rodents have assisted in building a wetland.Beavers often did work that went unacknowledged."We sort of have a blindness for beavers," Dr. Fairfax said, noting that they were often considered a nuisance because of their alarming size and capacity to rapidly change the landscape.
