Sunday, March 17, 2013

Animals that farm

People like to think that we're unique, but we aren't the only animals that farm. 
 
Beaver dam completely surrounding storm drain
 In the picture above  you can see the structure that a beaver has created all the way around a culvert that drains that area.   You can actually see the dam if you look at it in google maps.    It's right next to the local highway, which is how I spotted it a year or so ago.  I've watched this beaver build this for a year or so. 
Farming, beaver-style
 The water impounded by this dam floods the area, allowing the beaver to get to more and choicer trees, and giving it an easy way to escape predators.  They're vulnerable on land, but pretty safe if they're in the water. 
Beaver Damaged trees
 All of the trees in the photo above show beaver damage, and I'm sure that this critter will continue to clear these trees for the rest of its life; probably clearcut the whole thing. 

Flooded meadow, beaver dam at lower right
 So this is a critter that is changing its environment to better suit its purposes.  Effectively farming this area. 

The snohomish river basin, where I farm, was probably a maze of beaver dams when this area was settled by white people.  the local tribes hunted them for meat and fur, but it's pretty clear that they were widespread at the time.  We don't have very good information about the condition of the river deltas -- most of the settlers were busy diking and draining the areas to take notes on what was there before they started, and I mention this because one thing that people talk about is "restoring the land"...

You really have to ask yourself "restoring to what date?" to get this correct.  Are you aming to restore it to what was there before white settlement?  Before the local tribe?  Before humans colonized the americas?  Because each of those is likely a different landscape and different conditions. 

Our current theory is that woody debris and blocked flow are good for salmon, and a lot of effort is spent throwing logs and stumps into the fake wetlands that they construct.   This beaver is doing the same sort of job, but for its own benefit.  It's not thinking about the salmon or migratory birds or anything other than being able to get to more and tastier trees. 



1 comment:

Jonathan Corcoran said...

I've thought of them as little rat-humans. They do adapt, but their main strategy is to adapt their environment to suit their needs. I've learned a lot from our beavers--a little work every day can have large outcomes. They can have the pond, but I am not going to let them have the field:)