Chew’s Ridge Site Monitoring 2012

Speyeria adiaste clemencei 2011-12 transect totals

Chew’s Ridge colony

I conducted weekly standardized surveys of Clemence’s unsilvered fritillary at the Chew’s Ridge colony site from early June to late August, 2012, following protocol established for 2011 surveys.  See results of these 2012 surveys below, combined with 2011 data for comparison.

Asst. Professor Ryan Hill and grad student Khuram Zaman (University of Pacific), and I also conducted weekly mark/release/recapture population sampling to obtain a more accurate population estimate and collect other demographic and behavioral data.  Final results are still being tabulated, but early analysis suggests that last year’s population estimate was low: this year’s (2012) colony likely numbered between 500-1000 individuals; therefore, given last year’s longer flight season with a higher peak (see below), the Chew’s Ridge colony pop. size that year probably exceeded 1,000.

Single visits to the only other known S. adiaste colonies - on Pine Ridge and Skinner Ridge (1.5 mi. S, and 10 mi. W respectively from Chew’s Ridge) suggest an additional 1,000-2,000 individuals, giving a total 2012 pop. estimate of 2,000-3,000 individuals in the Ventana Wilderness of Monterey County.  For further discussion, see Weather Effects.

2011 surveys

2012 surveys