page_title: Joseph Grinnell
section_title: Grinnell Resurvey Project
hierarchical_section_title: Joseph Grinnell / Survey of California fauna / Grinnell Resurvey Project
caption_attribution_description: English: A simple diagram showing the change of elevation/range of the pinyon mouse.
context_page_description: Joseph Grinnell was an American field biologist and zoologist. He made extensive studies of the fauna of California, and is credited with introducing a method of recording precise field observations known as the Grinnell System. He served as the first director of the Museum of Vertebrate Zoology at the University of California, Berkeley from the museum's inception in 1908 until his death.
  He edited The Condor, a publication of the Cooper Ornithological Club, from 1906 to 1939, and authored many articles for scientific journals and ornithological magazines. He wrote several books, among them The Distribution of the Birds of California and Animal Life in the Yosemite. He also developed and popularized the concept of the niche.
context_section_description: The Museum of Vertebrate Zoology began the Grinnell Resurvey Project in 2002 using Grinnell's original survey of California fauna for comparison.  The resurvey team encountered difficulties, as the 2007 report on Yosemite noted  "the data from the original and current surveys cannot be directly compared because of differences in observer effort." 
  Project researchers worked in Yosemite National Park from 2003 to 2006. Using colorfully annotated maps dating from the late 1800s, the biologists revisited about 40 sites.  Some sites could not be resurveyed  because they are no longer accessible; one example is Lake McClure, a reservoir constructed in 1926. Lassen National Park was resurveyed in 2006, and the Warner Mountains in northeast California and south to the White Mountains in 2007.
  The resurvey report's section on birds noted problems in comparing the censuses: "In the original survey there was a large difference in terms of birds observed per unit time between J. Grinnell and T. Storer, with Grinnell having much higher scores than Storer for the same area. Grinnell and Storer counts also had a larger variation among their own censuses for a single site than we did during our survey."
  The Yosemite resurvey documented shifts in the geographic ranges of some mammals.  The majority of change is to higher elevation by a ratio of  2.5 to 1. A notable alteration in range is shown by the pinyon mouse (Peromyscus truei), where both the upper and lower range limits have moved upward in elevation. The resurvey biologists documented the pinyon mouse on Mount Lyell at elevation 10,500 feet. In Grinnell's Animal Life of the Yosemite,  the pinyon mouse (or big-eared white-footed mouse) is described as occurring in the Upper Sonoran Zone on the west slopes of the Sierra Nevada Mountains.
  The Upper Sonoran is a life zone between 1,000 and 3,500 feet above sea level.
  In the Yosemite transect, no significant change in avian species abundance was found. Grinnell documented 133 species and the resurvey team reported 140 bird species.
  
  The report's section on amphibians and reptiles noted healthy populations of mountain yellow-legged frog (Rana muscosa) at Yosemite's Dorothy Lake and breeding populations near Evelyn Lake. This species (or Distinct population segment) is listed as endangered by the US Fish and Wildlife Service.
  In 2013 a team of researchers from the San Diego Natural History Museum completed a five-year survey of the Grinnell Transect, Grinnell's 1908 study of the flora and fauna of Mount San Jacinto. In 60 surveys across 20 sites, they found the forest to be much denser than in Grinnell's time, with the loss of three species including a flying squirrel, and an increase in birds that like thick brush, such as the hermit thrush, the brown creeper and the Townsend's solitaire. The relative lack of leaf litter and decayed ground cover in Grinnell's time was considered to make the occurrence of hot and lasting fires in the forest impossible. With a much thicker understory in 2013, the team of researchers were forced by the Mountain Fire to evacuate their camp.
caption: Diagram of elevation change of Peromyscus truei
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