Friday, 1 May 2009

Speculations about aspen regeneration and a beaver feeds.

Some years ago I read that the global distribution of the two species of beaver coincided with that of aspen (Populus spp.). I was reminded of this a few days ago. While browsing through two books I came across passages that described the very precise requirements cottonwood (Populus spp.) seeds have if they are to germinate. They need a particular fine silt, such as is left in the aftermath of spring floods and the time during which they are viable is very short.

I wonder if our aspen, which seems to have such difficulty in reproducing sexually here, is constrained by the same limitations as North American cottonwoods and if so, to what extent the absence of beavers in Scotland for some hundreds of years, coupled with all the changes to rivers (drains for agriculture, etc.) and land management (heavy grazing) have had in making it difficult for aspen to reproduce sexually.

This evening I went out to check one of my trail cameras. Here is one of the clips of film. A yearling (I guess) beaver is gnawing at a small branch, takes a break to groom itself and then goes back to feeding.


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