[APWG] war on weeds & cheatgrass article

[Craig Dremann]

Dear Steve and All,

Thanks for your comments about cheatgrass and the Snakeriver
wheatgrass.  

One of the first questions that could be asked about that wheatgrass
patch, 18 years ago and today, is it an old population that has stopped
reproducing, or are there seedlings or other recruitment? 

A lot of the grasses across the Great Basin are old grandpas and
grandmas, and one reason is that they are grazed continuously, and not
rested even for one year out of 10, to allow seeds to ripen and produce
seedlings. 

In 1993, while surveying 100 miles of individual populations during a
period of good rainfall years, I found dozens of native grass
populations, but only one population was reproducing, with an age-class
structure containing young seedlings. 

It would be interesting to map the Great Basin's native grass
populations, and separate them into reproducing populations and the
non-reproducing grandpas and grandmas. 

Other major issues to contribute to the decline of the wheatgrass and
increase of the cheatgrass,  could have been the multiple droughts
and/or grazing of the wheatgrass during those droughts.  Was that
wheatgrass grazed, especially during the droughts?

There's been multiple severe drought in that period, from at least the
late 1990s to date--see the latest Great-basin drought at
http://www.drought.unl.edu/dm/monitor.html

What I've seen in the Great Basin, especially when I did my 1997
Megatransect survey at http://www.ecoseeds.com/megatransect.html, is
that the cheatgrass is only a default-weed, only moving into empty
spaces created when the native bunchgrasses have been grazed out, and
the native ecosystem is in tatters.

I noted mile-by-mile in 1997, the exact locations of all the empty
spaces along my Megatransect, so it would be interesting to go back now,
and see how many empty spaces got filled by the cheatgrass, and how many
spaces that had native grasses ten years ago, are still intact? 

If drought weakens a native grass stand in the Great Basin, and then
grazing during that drought opens up more empty space in the stand, the
cheatgrass has the perfect "vacancy" sign lit up for it, to move on in.

Sincerely,  Craig Dremann (650) 325-7333