Thank God for Beaver Dams
A recent study helped reveal the importance of beaver dams. Yet as a native of Canada, I have always been thankful for these furry rodents and their dams. (The beaver is the national animal of Canada and is depicted on the Canadian nickel.)
For two centuries the fur trade supported Canada’s economy—and almost all that fur came from beavers. Before the arrival of European settlers, Canada was home to at least 60 million beavers—nearly twice the current human population. At the height of the fur trade virtually every European man and woman of means owned a beaver coat and hat.
Though the Bible does not refer to beavers explicitly, it does describe their order. Genesis 1:24 mentions rodents as short-legged land mammals, one of three categories of advanced land mammals that God created on the sixth day to serve and please human beings and to facilitate the launch of civilization.
As I described in my latest book, Hidden Treasures in the Book of Job,1 rodents, including beavers, are ideal for meeting humanity’s clothing needs since they are the most efficient fur-producing animals. What is especially marvelous about the higher animals is how God designs them to benefit us in multiple distinct ways.
A team of geologists and geophysicists at Colorado State University, led by Natalie Kramer, recently discovered that beavers benefit humans far beyond provision of clothing. In the January 2012 issue of Geology, they published their results from ground-penetrating radar and near-surface seismic refraction mapping of a region in Rocky Mountain National Park.2 What they uncovered was evidence for beaver-induced sedimentation during the Holocene era (the past 11,700 years since the end of the last major glacial epoch or ice age).*
The magnitude of beavers’ contribution to the sediments struck Kramer and her associates. They found that 30–50 percent of all the above bedrock post-glacial sediments formed as a result of beavers building dams across waterways. Beavers, therefore, are one of the most important producers of valley sedimentation. So why has it taken so long for us to recognize this creature’s true significance?
First, human predation nearly drove beavers to extinction. In spite of heroic restoration efforts, the current population of beavers in North America stands at only 6–12 million while only several thousand Eurasian beavers remain. Second, humans aggressively limit both the size and permanence of beaver dams. I got to see the latter effect first hand at the Algonquin Radio Observatory in Algonquin Park, Ontario. Beavers there built dams of such enormous size that the water backup behind the dam threatened to flood out our entire complex of radio telescopes. Consequently, a team of engineers was assigned the task of dynamiting the beaver dam every six months.
A more obvious benefit of beaver dam building is, of course, the creation of wetlands and wet meadows (see figure 2). Wetlands and wet meadows support higher species diversity and species populations for plants, insects, invertebrates, fish, amphibians, reptiles, birds, and mammals. This abundance enables humans to harvest more food and more plant and animal products. Wild rice sold in stores, for example, comes almost entirely from Canadian wetlands and wet meadows. These ecosystems also provide greater ecological stability by offering superior protection from natural disasters and ecological catastrophes.
Less obvious benefits of beaver dam building include the manner in which these animals help purify our lakes, rivers, and waterways. The ponds that build up behind beaver dams help remove both carbon and nitrogen from the water by creating environments for storing carbon and processing nitrogen.
Removing nitrogen from the water is crucial because reactive nitrogen compounds flowing down river causes eutrophication, the blooming of cyanobacteria. This leads to hypoxia (oxygen depletion) and the generation of dead zones for fish and other animal populations. Eutrophication that currently plagues the Potomac River and much of Chesapeake Bay, for example, could be reversed, at least in part, by reintroducing beavers into the area.
Using beavers to remove carbon from our freshwater resources may prove even more crucial. As water flows downstream it becomes progressively more chlorinated as a result of water treatment for urban use. The chlorine combines with carbon to produce a variety of carcinogenic (cancer-causing) chemicals. Thanks to the industry of beaver dam and canal building, carbon is removed from the water environment and the accumulation of carcinogens in our drinking water supplies is kept in check.
Clearly, we have a lot to thank God for when it comes to the work of busy beavers. In addition to the physical and economical benefits mentioned above, beavers also famously set us an example of outstanding work ethic.
Thousands of years ago, Job declared in his debate with Eliphaz, Bildad, and Zophar, “Ask the animals, and they will teach you, or the birds of the air, and they will tell you.”3 As the rest of the book of Job explains,4 God designed the mammals and birds to teach us important lessons about ourselves, about God, and our need for a Savior. Thanks to past and new research, beavers are becoming a vital part of these lessons.
1. Hugh Ross, Hidden Treasures in the Book of Job (Grand Rapids: Baker, 2011).
2. Natalie Kramer, Ellen E. Wohl, and Dennis L. Harry, “Using Ground Penetrating Radar to ‘Unearth’ Buried Beaver Dams,” Geology 40 (January 2012): 43–46.
3. Job 12:7 (NIV).
4. Hugh Ross, Hidden Treasures in the Book of Job, 119–85.
*Please note the following corrections, per the main author of the study cited in this post (April 23, 2012):
“Post-glacial sedimentation did not include all sediments above bedrock. There was glacial sediments above bedrock and then post-glacial sediments above that. The post-glacial sediments composed a tiny fraction of the total valley fill, which was dominated by glacial sediments, only ~1.3 m, on average. So beavers did not contribute to large amounts of sediment accumulation, at least not where I studied. However, of that 1.3 m 30-50% was attributed to beaver activity. So beavers were important agents trapping and storing the sediment that was in the valley, but they did not cause large scale aggradation [sic] at my site. The sediments fine sediments that were trapped by beavers were likely very important maintaining a wet meadow ecosystem, which is now rapidly disappearing in their absence.”