Dear HCN,
Thank you for the
thoughtful coverage dealing with weeds across the West, and
especially the discussion of the cheatgrass/fire cycle problem. A
quick point of clarification, though. Your articles seemed to
return to a theme of grazing as a central cause. In my experience,
grazing may not be necessary for land to experience replacement of
native shrubs and grasses by cheatgrass and its close relative red
chess.
A good example is the Nevada Test Site,
where grazing has not been permitted by federal order for over 50
years. During this time, red chess and cheatgrass have invaded and
begun to replace the native shrub cover. They do that by
germinating months earlier and at seedling densities exceeding
10,000 per square meter: native species just cannot compete and
their recruitment becomes a rare event.
So,
although livestock and fire may have assisted the invasion and
dominance of cheatgrass and red chess in many locations, I suspect
that these and other weeds (examples include white top and Russian
knapweed) may not need any type of disturbance for them to
establish and replace native species within suitable climatic
zones. This is a truly scary situation, potentially affecting tens
of millions of acres across the
west.
David
Groeneveld
Santa Fe, New
Mexico
This article appeared in the print edition of the magazine with the headline Weeds don’t need cows to spread.
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