2006 Resurvey Work

May through September

Read the Report (PDF) Lassen peak team

In May of 2006, biologists with the Museum of Vertebrate Zoology (MVZ) at UC Berkeley will began to inventory the terrestrial vertebrate species within the “Lassen Transect,” a 3,000 square mile swath of northern California from the Sacramento River to the Nevada border that includes Lassen Volcanic National Park. They visited five major sites that Grinnell focused on in his surveys from 1924 through 1929. To maximize the comparison with the historic data, MVZ biologists revisited the sites on approximately the same dates and used similar methods as Grinnell and his colleagues.

In six days per site, the MVZ team inventoried the birds, small mammals, reptiles and amphibians using a suite of detection techniques. These surveys will expand upon a recent small vertebrate inventory conducted in the western half of the park by Lassen Volcanic National Park biologists, which documented several small mammal species new to the park.

The MVZ team has almost completed a similar resurvey of the Yosemite region. Comparison with the historical data has revealed some exciting and potentially troubling trends. The distributions of several species have expanded to higher elevations, and the ranges of some of the highest-elevation species have become sharply reduced. For example, the upper limit of piñon mouse ( Peromyscus truei ) has increased nearly 3000 ft, and the lower ranges of pika ( Ochotona princeps ) and alpine chipmunk ( Tamias alpinus ) have retracted nearly 2000 ft since Grinnell's surveys. These patterns are consistent with predictions from climatic warming models. By examining the Lassen Peak region and other mountainous areas throughout California, the MVZ biologists can determine whether such changes are widespread throughout the state. The resurveys will also set a new baseline for future monitoring efforts.

John Perrine is the coordinator for the Grinnell Resurvey Project in northern California. His email is perrine@nature.berkeley.edu