[APWG] California drought suppressing native understory, allowing exotics to spread?

[Craig Dremann]

Dear All,

There's an exceptional drought going on here in California, see attached
map.  

The last time we had drought conditions like this, was in the late
1980s, and the suppression of the vegetation understory allowed the
yellow star thistle to spread, so that the number of acres covering
California nearly doubled between 1985 (7.9 million acres) and 2005 (15
million acres).

No adequate investments have been made in the last 25 years, by either
private land owners, public land management agencies, or Federal, State
and County highways, in California to manage the yellow star thistle on
their lands, so its spread increases significantly every year.  

Will this new drought enable the weed to spread even faster---maybe
doubling the million of acres it already covers?  If the trend continues
at the same rate, even without the drought's help, then the graph looks
like 28 million acres of California should be covered by 2025?

Also, this week, there's significant droughts in Arizona, Colorado,
Florida and the Dakotas--will those drought help the spread of exotic
plants in those states also?

Sincerely,  Craig Dremann, Redwood City, CA (650) 325-7333
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