[RWG] Weeds causing native grasslands go extinct in SF Bay Area

[Craig Dremann]

Dear All,

Here is an example of an entire native grassland ecosystem, here in
California, being pushed to the brink by weeds.

Bill Korbholz's presentation at our San Mateo County (California) Weed
Management Area meeting last week, showing the extinction of Edgewood's
beautiful native serpentine grasslands and wildflowers since the 1970s,
caused by exotic grasses and other weeds---even after his non-profit
group "Friends of Edgewood" has hand-pulled over 2 million weeds out of
that natural Preserve.

The Edgewood Preserve presentation was the encouragement I needed to go
out this morning to remeasure Mid-pen's Open Space's Russian Ridge,
which is about 7 miles west of Palo Alto, and compare it to my 2003
data.  

Simply put, Russian Ridge still has some isolated pockets of native
grasses and wildflowers that could be managed so they would spread to
cover larger areas. 

And my May 2003 measurement of this area found an average of 13% native
perennial grass cover of five different species, plus a 25% cover of
wildflowers consisting of eleven species, and 2% cover of native shrubs.

UNFORTUNATELY, today's July 29, 2006 remeasurment of Russian Ridge, only
three years later, found some disturbing and sharp downward trends for
the perennial native grasses and a very rapid increase in Harding grass
cover.

A DANGEROUS DROP in the perennial native grass cover has occurred at
Russian Ridge, to less than half of what it was only three years ago, to
5.2%---which means that the
whole perennial grass component could become extinct within 3-5 years. 

THE TWO WORST CASES at Russian Ridge were the Nassella pulchra (Stipa)
2.3% cover in 2003 within the measured area (1500 ft. linear toe-point
transect), went to zero in 2006; plus the Melica cover also dropped to
zero, from 0.2% cover in 2003. We are watching the slow-motion
extinction of an entire ecosystem.

HARDING GRASS, the nasty perennial weed that kills 99% of the California
native grassland species, increased within the Russian Ridge area from a
2003 cover of only 0.5%, to an awesome 7.4% cover in 2006--an amazing
five-fold increase in spread every year for the past three years. 

A NEW DEADLINE has appeared in 2006, with an immediate need for
inventing successful technologies to restore native grasslands in a
hurry before they go extinct.  This slow-motion extinction probably
applies to other native grassland ecosystems around the country,
especially those which are weed infested.

HAS EVERYONE remeasured their transects recently?  Is the trend moving
upwards or sharply downwards?  

More details and photos are at 
http://www.ecoseeds.com/invent.html 

Sincerely,  Craig Dremann (650) 325-7333