Tahoe Nugget #209:
Butterflies Waiting for Spring
June 21, 2011
The snowpack is melting quickly at the lower elevations, but a thick frozen mantle persists up top and in the north and east-facing basins. Several local ski areas will take advantage of the unusual
conditions to run chairlifts over the Fourth of July weekend for anyone jonesing for more turns or angling for bragging rights and a t-shirt.
Record snow depth at the Central Sierra Snow Lab on June 12, 2011.
July is right around the corner, but Lake Tahoe's surface water temperatures are still chilly, ranging in the mid 50s
(a little colder in Tahoe Vista), which makes for bracing water sports. More importantly, Tahoe's surface elevation
is now above 6,227 feet and rising, good news for water supplies, boating enthusiasts, and the Truckee River ecosystem.
June 2011 snowpack at Serene Lakes is still causing trouble.
The late season snowpack is impacting the area and human and animal behavior. To avoid snow, mountain bikers
and hikers are staying east of the main Sierra range or heading for the lower elevations to enjoy their sports.
Engorged streams and rivers are running cold and fast, with flood advisories, watches and warnings currently posted on many regional water courses. Snowmelt has been manageable so far and available upstream water
storage has mitigated most potential flooding risks.
One small display from Charles McGlashan's extensive collection.
Something more subtle that most people won't notice is that the cold spring has delayed butterfly emergence on
Donner Pass. Professor Art Shapiro, a renowned world-class entomologist and ecologist with the University of
California – Davis, has been monitoring butterflies in the area for more than 35 years. I met him recently at Norm
Saylor's Donner Summit Historical Society in Soda Springs and he said that in his 35 years studying butterflies in the area, this is the latest date that none have been observed flittering about.
McGlashan exhibited his butterfly collection and historic Donner Party relics in the cylindrical tower perched on the giant granite boulder on the right. His house is to the left. The McGlashan Mansion burned
down in 1935, but the tower with its collection of butterflies and artifacts was spared.
Truckee has a long history associated with butterflies because town patriarch Charles F. McGlashan, an author,
attorney, teacher and noted entomologist, was well known for his own extensive collection and expert field
knowledge of the fascinating insects. McGlashan was in the right spot. According to Dr. Shapiro, with well over
100 distinct species the Donner Summit area boasts such diversity the site ranks as one of the "richest butterfly faunas documented in North America, north of Mexico."
Whimsical arrangement from McGlashan's collection.
Dr. Shapiro recently published a major paper on his remarkable butterfly research that uncovered the negative
impacts urban development and climate change are having on butterfly diversity at his 11 study sites. Species
diversity at all his sites, including near sea level, the central valley and Sierra foothills, is declining rapidly. In the
mountains the loss is slower, while at the higher monitoring sites butterfly diversity is actually increasing as lower
-elevation species escape the warming climate by moving upslope to cooler regions. Diversity is decreasing,
however, for those butterflies adapted to the coolest air at the highest elevations near and above timberline as temperatures there also increase. (http://butterfly.usdavis.edu)
With all the snow above 7,000 feet, it's no surprise that butterflies are taking their time emerging for the summer.
Just a few weeks ago the snowpack at the Central Sierra Snow Laboratory near Soda Springs was nearly eight
feet deep, the greatest depth of record for the date at their study site. The nearly 54 feet of snow that fell at the
Snow Lab during winter 2011 is third greatest since World War II, behind only 1952 (812 inches/67.7 feet) and 1983 (671 inches/56 feet), two iconic winters that had tremendous impact on the region.
The chairlifts are silent, but Soda Springs Mountain Resort still has top to bottom snow cover in mid-June 2011.
After enduring such a long and stormy winter, you can't blame the butterflies for being gun-shy about leaving the safety of their protected nests.