This shows a typical example how beavers manage water in wetlands in Northern Canada when they are relatively undisturbed. The image below gives a simple interpretation of the area. This area is part of the northern edge of the Boreal zone. Pieces of precambrian bedrock are visible as "islands" in a large wetland area. Most of the watermovement is in the form of "ground water" flows in the wetlands, and the beavers had to build extensive dams to contain the flow.



Beavers are typically boreal and temperate species surrounded by trees which provide a good food supply. The Northern Limit of the Beavers is interesting since beavers seem to follow climate warming trends (not just the last decades, but and are migrating north since the little ice age, the last period of climate cooling a few hundred years ago). With the acceleration in warming, the rate of migration into the subartcic may accellerate along the rivers and streams where they live of willow and alder.
Apparently Moose and Red Fox are also moving into the subarctic, but their "foot print" is not visible on a satellite image. Google Earth with its incredible ability to scale into high resolution detail makes beaver activity and possibly its migration north "mappable"


I am working on a series of transects through Canada's north to establish a sort of baseline on the GE visible status of beaver . Results will be added to this thread on a regular basis. By the way, the typical beaver example above is at the green place mark of the image below which shows a series place marks for site I have looked at


http://www.geostrategis.com