WERC Highlights -- October 2004

Predator Management: USGS scientist William I. Boarman of the Western Ecological Research Center has been invited to serve as the chair of an expert panel on raven management at Point Reyes National Seashore on Nov. 4-5, 2004. Snowy plovers and other birds breeding at this national seashore have been suffering from intense predation by ravens for several years, and it is thought that agricultural practices at the park facilitate raven population growth and predation activities. The expert panel is being convened to provide advice to park managers on how livestock management methods might be modified to reduce benefits provided to raven populations. Other panelists include Richard Knight, Colorado State University; Steven Beissinger, University of California, Berkeley; and Robert Budd, The Nature Conservancy. (William I. Boarman, San Diego, CA, 858-637-6880, william_boarman@usgs.gov).

Those Tell-tale Hearts: Wildlife Managers often use buffer zones to separate wildlife from human activities, which can save animals from spending energy in response to human disturbance. This buffer spacing is often determined from the distance at which a species flushes in response to human activities. In a USGS study published in The Wilson Bulletin, scientists radio tracked tule greater white-fronted geese to monitor cardiac response to human approach. They found that flushing distance is a reasonable measure for creating buffer zones when human disturbances are likely to be short in duration, but alert distance may be a better indicator of stress response when disturbances are likely to persist. Upon being approached by a human, the marked geese flushed and flew from the ground on average at a distance of 47 meters away. However, their heart rate increased by 36 percent from the observer’s initial approach to an abrupt increase in heart rate that occurred 5 seconds before they took to the air. Furthermore, heart rate nearly tripled over a 9-second period immediately before and after flushing. For more: http://www.werc.usgs.gov/pubbriefs/ackermanpboct2004.html. (Josh Ackerman, Davis, CA, 530-752-0485, jackerman@usgs.gov) Citation: Ackerman, J. T., J. Y. Takekawa, K. L. Kruse, D. L. Orthmeyer, J. L. Yee, C. R. Ely, D. H. Ward, K. S. Bollinger, and D. M. Mulcahy. 2004. Using radiotelemetry to monitor cardiac response of free-living tule greater white-fronted geese (Anser albifrons elgasi) to human disturbance. Wilson Bulletin 116(2):146–151.

Mountain Yellow-legged Frogs: USGS scientist Adam Backlin of the Western Ecological Research Center was quoted in an Oct. 25, 2004 story in the Press-Enterprise (Riverside, CA) about the October 2003 fires and subsequent flooding that deposited sediments in City Creek (San Bernardino Mountains), making it uninhabitable for imperiled mountain yellow-legged frogs. Prior to flooding, 11 frogs were removed from the creek in an emergency rescue effort and are in temporary care of the Los Angeles Zoo: http://www.pe.com/localnews/inland/stories/PE_News_Local_rescued26.57c20.html. (Adam Backlin, Carlsbad, CA, 760-931-1101 x235, abacklin@usgs.gov)

Mojave Desert Science: USGS scientists will give oral and poster presentations at the Desert Managers Group Mojave Desert Science Symposium, to be held at the University of Redlands, California, on Nov. 16-18, 2004. Four theme sessions (threats, ecosystem function, rehabilitation, scales and sustainability) will follow symposium keynote presentations of the first morning. Each theme will be presented as a series of four invited plenary talks, followed by a related poster session of volunteered presentations. The meeting will conclude with a panel discussion. An optional one-day field trip on Nov. 19 will focus on ecological impacts to the southern California deserts, abiotic factors relevant to understanding these impacts, and restoration approaches. For more: http://www.dmg.gov/mdss. (Lesley DeFalco, Henderson, NV, 702-564-4507, lesley_defalco@usgs.gov)

Desert Tortoise Lectures: USGS scientist Kristin Berry of the Western Ecological Research Center will be giving three lectures at the 13th Annual Desert Tortoise Surveying, Monitoring, and Handling Techniques Workshop, a two-day training session sponsored by the Desert Tortoise Council for government agency biologists and contractors on Nov. 6 and 7, 2004, in Ridgecrest, California. The lectures will be on a general overview of desert tortoises living in the Mojave and Colorado deserts, threats to desert tortoises, field evaluations of tortoises for health and disease, and effects of diseases on populations. For more info: http://www.deserttortoise.org/workshop.html. (Kristin Berry, Moreno Valley, CA, 909-697-5361, kristin_berry@usgs.gov)

River Science: USGS scientist Roger Hothem of the Western Ecological Research Center presented a talk entitled "Bioindicators of contamination by mercury and other metals in waters of Northern California impacted by abandoned mines" at the National Research Council's “Committee on River Science at the USGS” meeting on Oct. 7 in Sacramento. The NRC, part of the National Academy of Sciences, will provide guidance and advice to the USGS on the following issues: of the many river science questions, which should be a high priority for the USGS, which hydrologic, geomorphic, chemical, and biological variables should the USGS monitor to provide the information needed to address river science issues, and what should be the underlying design principles behind USGS River Science research? (Roger Hothem, Dixon, CA, 707-678-0682 x626, roger_hothem@usgs.gov)

Postfire Monitoring: USGS scientist Mark Mendelsohn of the Western Ecological Research Center was interviewed on Oct. 20 about post-fire monitoring that USGS is conducting on the arroyo toad and other species in southern California by a freelance writer for the San Diego Fire Recovery Network working on an article about wildlife after the October 2003 fires. (Mark Mendelsohn, San Diego, CA, 858-637-6888, mmendelsohn@usgs.gov)

Least Bell’s Vireos Unable to Deter Cowbirds at Nest: Cowbird parasitism is considered one of the factors responsible for declines in many sensitive riparian birds in California, especially those like the endangered least Bell’s vireo whose distribution and abundance have been severely reduced by habitat loss. Because this vireo is a recent host, it may lack effective natural defenses against parasitism observed in mid-western Bell’s vireos and other species that share a long evolutionary history with cowbirds. Using miniature video cameras, USGS scientists Barbara E. Kus and Bryan L. Sharp of the Western Ecological Research Center documented least Bell’s vireo interactions with cowbirds and their unsuccessful nest defense against parasitism, reported in a recent issue of The Wilson Bulletin. Parasitism was recorded at 3 of 19 nests monitored at a long-term study site on the San Luis Rey River in San Diego County, during the laying and early incubation stages, when cowbirds typically parasitize nests. Abandonment of parasitized nests followed by re-nesting may currently be the only natural defense by the least Bell’s vireo against parasitism. For more: http://www.werc.usgs.gov/pubbriefs/kuspboct2004.html. (Barbara Kus, San Diego, CA, 858-637-6881, barbara_kus@usgs.gov) Citation: Sharp, B. L. and B. E. Kus. 2004. Sunrise nest attendance and aggression by Least Bell’s Vireos fail to deter cowbird parasitism. Wilson Bulletin 116(1):17-22.

Reconstructing Historical Changes Using VTM Data: In recent years, numerous studies have made use of data that were collected over 70 years ago from more than 18,000 plots by the California Vegetation Type Map (VTM) project to reconstruct historical changes in vegetation distribution in forests, woodlands, and shrublands. In the October issue of the journal Madroño, USGS scientist Jon E. Keeley of the Western Ecological Research Center identified some critically important flaws in some of these studies, which stem from the fact that the VTM plots cannot be precisely relocated. Keeley’s results suggest that the broad generalizations made about historical changes using VTM plots are likely valid. However, his results raise serious questions about many of the published accounts that report very specific changes based on a single or just a few plots. Keeley also suggested two approaches for increasing the credibility of studies that use these historical VTM data. For more info: http://www.werc.usgs.gov/pubbriefs/keeleypboct2004.html. (Jon Keeley, Three Rivers, CA, 559-565-3170, jon_keeley@usgs.gov) Citation: Keeley, J. E. 2004. VTM plots as evidence of historical change: Goldmine or landmine? Madroño 51:372–378.

Santa Cruz Island Vegetation: USGS scientist Kathryn McEachern completed a two-year extensive plot-based sample of Santa Cruz Island vegetation, for use by the National Park Service, University of California Reserve System, and The Nature Conservancy. The samples provide the first island-wide description of the vegetation. A multi-year, multi-agency pig eradication project will begin on the island in 2005, and USGS is using the data to design a long-term monitoring plan for the island. The data are also being used to map and define habitat for recovery of the endangered island fox (Urocyon littoralis). (Kathryn McEachern, Ventura, CA, 805-658-5753, kathryn_mceachern@usgs.gov)

Santa Cruz Island Plants: USGS scientists Kathryn McEachern and Katie Chess of the Western Ecological Research Center led an Oct. 9 field trip to Santa Cruz Island, associated with the CalIPC meetings in Ventura, California. Objectives of the 5-mile round-trip hike were to discuss invasive plant concerns on the island, and view an upcoming recovery project for the endangered island bedstraw (Galium buxifolium) that requires removal of a tenacious invasive plant, Vinca major, from its immediate habitat. (Kathryn McEachern, Ventura, CA, 805-658-5753, kathryn_mceachern@usgs.gov)

Bats: On Oct. 6, USGS scientist Drew Stokes of the Western Ecological Research Center gave a lecture about identification of southern California bats and bat habitats to a group of about 20, mainly local biologists, at the San Diego Natural History Museum. Much of the information presented was based on USGS bat research in San Diego County. (Drew Stokes, San Diego, CA, 858-637-6885, dstokes@usgs.gov)