FRIENDS OF EDGEWOOD NATURAL PRESERVE
|
FRIENDS OF EDGEWOOD NATURAL PRESERVE
|
|
|
MOWING FOR BUTTERFLY RESTORATION By Stuart Weiss, Ph. D. The Bay checkerspot butterfly (Euphydryas editha bayensis) population at Edgewood went extinct in 2002, the victim of a "drive-by" extinction. Emissions of ammonia and nitrogen oxides from 100,000+ vehicles on Highway 280 fertilized a substantial area of serpentine grassland and allowed for invasion of Italian ryegrass (Lolium multiflorum) onto the nutrient-poor soils. In May and June 2005, approximately 10 acres of serpentine grassland at Edgewood were mowed and weedwhacked. Based on results of experiments executed in 2001 through 2004, this treatment will reduce the cover of ryegrass, and increase the cover of California plantain (Plantago erecta), the primary food plant for the butterfly, and generally increase native species diversity. The timing of mowing is critical; catching the ryegrass
before it fully ripens its seeds greatly reduces grass cover the following year.
Mowing also breaks up the thatch and duff layer that have accumulated through
time, and disperses ripened seeds of numerous native wildflowers into newly bare
areas where they will thrive next year. This year's mowing was funded by a
$10,000 grant from PG&E made available through the San Mateo County Parks
Foundation. |
|