Warner Mountain Field Research - Trewhitt Mammalogy Lab The Warner Mountains are part of the Modoc Plateau, which is located in the northeastern corner of California and is 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. The Warner Mountain range basically 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 2001 Stephanie Trewhitt, John Matson and Rod Myatt have been conducting field research in the Warner Mountains. John Matson retired from San Jose State University and Stephanie Trewhitt along with Rod Myatt have continued the Warner Mountain research and have also branched out into other ecological questions. Ongoing field research focuses on small mammal community structure; species diversity, and relative abundance of small mammals in the Warner Mountains of Modoc and Lassen Counties, California. Mammalian community structure is analyzed in relation to varying elevation gradients habitat associations, and the effects of fire in the mountain range.

Several hypotheses are being addressed and tested with the data that is collected. 1. Small mammal diversity changes within three different habitat associations after the Blue Fire. 2. Small mammal diversity changes with elevation and habitat associations. 3. Small mammals diversity and abundance in isolated Aspen groves in the Southern Warner Mountains. 4. Current small mammal community structure has not changed from that recorded by researchers from the MVZ in the early 1900’s. (The Grinnell Resurvey Project)

People Involved: Stephanie A. Trewhitt M.S. (Trewhitt Mammalogy Lab at San Jose State University) Instructor Department of Biological Sciences, San Jose State University San Jose State University, San Jose, CA - BS Biology (Conservation) 2000 and MS Biology (Organismal, Conservation and Ecology) 2002

I have been teaching in the biological sciences since graduation in 2002 at several San Francisco Bay Area universities and community colleges. Teaching at different schools has enabled me to teach a variety of biology courses including California Wildlife – Animals and Vertebrate Evolution and Natural History, Ecology, General Biology, Vertebrate Zoology, Conservation Management Techniques and Mammalogy. My research interests lie mostly in California mammals. Previous studies include surveying the biodiversity of mammals in the San Lorenzo River Redwoods, behavior and food habits of coyotes in the San Francisco Bay Region, seasonal abundance of rodent species in different habitats in the San Francisco Bay Region, habitat characteristics of rodents along varying elevation gradients, mammal community structure in different habitats in the Warner Mountains, Modoc Co. California, the range expansion of Sciurus griseus into the Warner Mountains and small mammal community structure in newly acquired lands in Pinnacles National monument. Publications: Trewhitt, S.A. Getting Started - Photograph credit, photo 6. 2011. Longman Earth Science textbook. Pearson and Longman publishers. Sikes, R.S., Gannon, W.L., and The Animal Care and Use Committee of the American Society of Mammalogists. 2011. Guidelines For the Use of Wild Mammals in Research by the American Society of Mammalogists. Journal of Mammalogy, in press. I co-authored this paper as a member of this committee. Matson, J.O., Laudenslayer, W.F. Jr., MacDonald (Trewhitt), S.A., and M. Flores. 2010. Range Expansion of the Western Gray Squirrel (Sciurus Griseus) in Northwestern California. Western North American Naturalist, 70(2): 266-269. Gannon, W.L., Sikes, R.S. and The Animal Care and Use Committee of the American Society of Mammalogists. 2007. Guidelines of the American Society of Mammalogists for the use of Wild Mammals in Research. Journal of Mammalogy, 88(3): 809-823. I co-authored this paper as a member of this committee. Reider, A., MacDonald (Trewhitt), S.A., Schelin, C., Matson, J.O., and Parr, L. 2005. Examining Gene Flow in a Population of Peromyscus maniculatus in the Warner Mountains Using Mitochondrial DNA Sequence of the Cytochrome B Gene. Peromyscus Newsletter. Number 39 Spring.

Rod Myatt Professor Emeritus - Botany - San Jose State University Rod has been working with Stephanie and John in the Warner Mountains since 2001. He is our plant expert and his expertise is critical to every research project being conducted in the Warner Mountains. In addition to trapping of small mammals at each trap site we take detailed vegetative data to help us answer our ecological questions.

Dan Corral (Graduate student, Trewhitt Mammalogy Lab at SJSU) San Jose State University, San Jose, CA - BS Biology (Conservation) 2010

Dan graduated from SJSU in 2010 with a BS in Biological Sciences concentration in Conservation Biology. He has studied the Biodiversity in Huddart park, San Mateo Co. California and plans do to his Masters research on the community structure of small mammals in isolated Aspen groves in the Southern Warner Mountains.

Trewhitt collaborates with UC Berkeley on the Grinnell- Resurvey Project- Warner Mountains Transect 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. In 2005 Trewhitt, Matson and Myatt, as part of their small mammals community structure focus, trapped at Shields Creek (5900 ft) and the Head of the North Fork of Parker Creek (7300 ft), these are also two of the sites that were surveyed in1910 by Bryant, Stern and Taylor. Many of the same species that we trapped in 2005 were also trapped in 1910. In 2006, we visited and resurveyed Warren Peak, (see 2006 report for details). In 2007, plans are to continue resurveying the remaining sites from 1910, in order to provide a more complete picture in how the mammalian fauna have changed over the last almost 100 years.

2006 Report: In August of 2006, biologists from San Jose State University resurveyed Warren Peak the highest and southerly most site of the 1910 “Warner Mountain Transect”. Following the same protocol as the Lassen and Yosemite Transects, this site was visited on approximately the same dates, the same trapping location, and used similar trapping methods as in 1910. According to GPS coordinates (in 2006, N41.38463 ° W120.21592° WGS 84 elev. 8905ft) the trapping locations were very close to those trapped in 1910. For five days the SJSU team (Trewhitt, Matson and Myatt) trapped mammals and completed vegetations surveys in the same habitat types, meadow and white bark pine forest, as the 1910 team, inventorying the small mammals. As part of this year’s survey the team also completed vegetation analyses of the trapping locations and documented the area with photographs similar to those taken in 1910. The resurvey of Warren Peak yielded many of the same mammals that were surveyed in 1910. However, one major difference was that there were no signs of Pika (Ochotona princeps) anywhere; even though the MVZ has records of them at this locality from the 1910 expedition and the talus slopes seemed to still provide ideal habitat. The only mammals observed using the talus slopes were chipmunks (Neotamias amoenus) and Douglas tree squirrels (Tamiasciurus douglasii). Small mammals caught in the meadows and white bark pine forest included Peromyscus maniculatus, Microtus montanus, Tamiasciurus douglasii, Zapus princes, Sorex spp., Neotamias amoenus, and Spermophilus lateralis. Spermophilus beldingi were present and photos were taken even though trapping yielded no captures. Mule deer, coyote, and signs of badger were also present in very small numbers. It is noted that badgers were present and trapped by Bryant, Stern and Taylor in 1910 and then according to NFS biologists were not present for some time and have recently begun to reappear (Mary Flores and Edith Asrow 2006 pers. comm.).

Recent Publications and research titles from the Warner Mountains: 2010. Range Expansion of the Western Gray Squirrel (Sciurus griseus) in Northeastern California. Western North American Naturalist, 70(2):266-269. (J.O. Matson, W.F. Laudenslayer Jr., S.A. Trewhitt, & M. Flores) 2007. Habitat Partitioning by Two Sympatric Species of Chipmunk (Genus: Neotamias) in the Warner Mountains of California. Bull Southern California Acad. Sci. 106(3):208-214. (M. Poppenroth & J.O. Matson) 2004. Diets of Nesting Northern Goshawks in the Warner Mountains, California. Western North American Naturalist, 64:359-363. (R. L. Promessi, J. O. Matson, & M. Flores)