Warner Mountains Transect -- Survey Lead by Stephanie MacDonald

The Warner Mountains, located in the northeastern corner of California between the Alturas Plain and Surprise Valley (Nevada), are part of the Modoc Plateau, defined by the High Cascade volcanoes to the west, the Sierra Nevada to the south, continues north into Oregon and fades eastward into the Basin and Range Province in northern Nevada. The Warner Mountains are the westerly most range of the Great Basin and Range Province. Its gentle sloping, conifer-covered western flank and steep, stark eastern face mimic the rain shadow effects of the Sierra Nevada as well as its often extreme temperature and weather conditions. Sudden summer thunderstorms and fierce winter gales are common in the Warner Mountains.

The Warner Mountain range consists of big block of volcanic rocks, originating from basalt flows with some sedimentary rocks. The youngest flows in the Warner Mountain Range, erupting some six million years ago or so, stand at an elevation of 9,700 feet approximately 5,200 feet above the floor of Surprise Valley. The Surprise Valley fault, located on the east side of the range, has moved approximately two vertical feet every thousand years, comparable to the Sierra Nevada fault and is extremely fast in geologic time.

Since before Grinnell's time, the Warner Mountains have undergone pressures from humans, from grazing in the lowlands of the Alturas Plain and fire-suppression policies for most of the twentieth century. Changes in major vegetation have been documented even in the South Warner Wilderness area, namely increasing White Fir and decreasing Yellow Pine stands and invasions of certain grasses and shrubs in the foothills.

The Warner Mountains transect was originally surveyed from May through August in 1910 by Grinnell’s colleagues Harold C. Bryant, N.B Stern and Walter P. Taylor. Grinnell visited the area in 1922 trapping along the Pit River just south of Goose Lake, which lies approximately 16 miles north of Alturas. According to the historic maps from the field notes Bryant, Stern and Taylor visited seven different trapping locations from Sugar Hill in the north to Warren Peak in the south.

Since 2001 Stephanie MacDonald and John Matson have been conducting field research in the Warner Mountains. Their ongoing field research focuses on small mammal community structure; species diversity, and relative abundance of small mammals in the Warner Mountains of Modoc County, California. The community structure is analyzed in relation to varying elevation gradients and habitat associations within the mountain range.

Several basic hypotheses are being addressed and tested with the data collected.

  1. Small mammal diversity changes with elevation and habitat associations.
  2. DNA sequence analysis may reveal contact zones between populations of small mammals.
  3. The current small mammal community structure has not changed from that recorded by researchers from the MVZ in the early 1900’s.