WERC Highlights -- September 2003

Tortoise Health and Declines: USGS scientist Kristin Berry of the Western Ecological Research Center will present two papers at the 25th Anniversary of the Gopher Tortoise Council, which will be held at Wekiwa Springs State Park, Apopka, Florida, October 3-5, 2003. She will discuss declines of threatened Mojave desert tortoise populations in "Declining trends continue in desert tortoise populations, California, USA" on Oct. 4; on Oct. 5 in a 2-hour tortoise health workshop, she’ll present protocols for systematically documenting a variety of health, disease, and environmental parameters, and the use of resulting comprehensive databases to correlate clinical signs of disease with population status and trends in "Health assessments of tortoises in the field: an integral part of research, monitoring, and mitigation projects." (Kristin Berry, Moreno Valley, CA, 909- 697-5361, kristin_berry@usgs.gov)

Invasive Species Symposium: USGS scientists of the Western Ecological Research Center will give talks at the Invasive Species Symposium of the Western Section of The Wildlife Society in Sacramento, California, Oct. 14-16, 2003. Susan Wainwright-De La Cruz will discuss effects of the exotic Asian clam, which bioaccumulates higher levels of contaminants than native invertebrates, in “Dining out in San Francisco Bay: How does a new clam on the menu influence wintering diving ducks?” Glenn Wylie will speak about two alien species and their impact on a threatened snake in “Trophic interactions among non-native crayfish and bullfrogs and endemic giant garter snakes at Colusa National Wildlife Refuge.” (Susan Wainwright-De La Cruz, Vallejo, CA, 707-562-2000, susan_wainwright@usgs.gov; Glenn Wylie, Dixon, CA, 707-678-0682 x616, glenn_wylie@usgs.gov)

Raven Predation Risk: In the western Mojave Desert, common ravens have increased in numbers by 1,500 percent over the past 25 years, subsidized by human developments in the region. USGS scientist William I. Boarman of the Western Ecological Research Center and William B. Kristan, an adjunct professor at California State University at San Marcos, found that young desert tortoises in the western Mojave Desert are at risk of predation both from non-breeding ravens living in and around human communities and from nesting pairs, which are more evenly distributed across the landscape. The risk is distributed across the landscape wherever ravens are found, with little potential for safe havens from possible attack. Their study is published in the September issue of the journal Ecology. To assess the risk of predation by ravens, the scientists set 100 artificial baits (2-inch Styrofoam models resembling baby tortoises) over about 300 square miles in the western Mojave Desert on and around Edwards Air Force Base. The scientists assigned scores by whether the baits were attacked (29 had raven bill impressions), and then developed a computer model for risk of raven predation on desert tortoises based on these data and on surveys of raven abundance at the sampling points. Predation risk was close to 100 percent near large groups of ravens that were distant from successful nests, usually near landfills. Predation risk reached between 44 and 59 percent near successful nests that had relatively small numbers of ravens in the vicinity. A summary of the article and management implications is available at: http://www.werc.usgs.gov/pubbriefs/boarmanpbsep2003.html. Citation: Kristan, W. B, III, and W. I. Boarman. 2003. Spatial distribution of risk of desert tortoise (Gopherus agassizii) predation by common ravens (Corvus corax). Ecology 84(9):2432-2443. (William I. Boarman, San Diego, CA, 858-637-6880, william_boarman@usgs.gov)

Marine Mammal Declines: USGS scientist Jim Estes was interviewed about a new article in the Proceedings of the National Academy of Sciences by him and colleagues on sequential declines in marine mammal species in the North Pacific following collapse of the region’s great whale fishery. News coverage is worldwide, including BBC, MSNBC, AP, UPI, NPR, New York Times, Washington Times, Los Angeles Times, Sydney Telegraph, Nature.com, Discovery Channel, Belfast Telegraph, Science Daily, Seattle Post-Intelligencer, Salem Statesman Journal, and picked up by other U.S. newspapers. (Gloria Maender, Tucson, AZ, 520-670-5596, gloria_maender@usgs.gov)

Marin Headlands: A new 45-minute documentary of the Marin Headlands Institute takes a one-year look at wildlife and seasonal changes in the Marin Headlands of the Golden Gate National Recreation Area. It includes a coyote vignette in which USGS scientist Erin Boydston conducting radio-tracking and discusses coyote research. (Erin Boydston Sausalito, CA, 415-331-0639, eboydston@usgs.gov)

Giant Garter Snake Workshop: USGS scientist Glenn Wylie of the Western Ecological Research Center is the keynote speaker at a two-day giant garter snake workshop in Elk Grove, California, Sept. 24-25. Sponsored by the Western Section of the Wildlife Society, the workshop is for biologists involved in the management, regulation and mitigation for the threatened snake. Wylie will discuss the natural history and biology of the snake, which is found only in California’s Central Valley. Speakers from other federal and state agencies, and other organizations, will address other topics including recovery planning, restoration, genetics, and distribution. For additional information: http://www.tws-west.org/meetings.html#ggs. (Glenn Wylie, Dixon, CA, 707-678-0682 x616, glenn_wylie@usgs.gov)

Marine Mammal Declines: The rapid depletion of at least a half million great whales from the North Pacific Ocean by intensive industrial whaling over 50 years ago may have unleashed a complex ecological chain reaction that has since rippled resoundingly from ocean to coastal ecosystems, according to a group of scientists writing in the Proceedings of the National Academy of Sciences online Early Edition, the week of Sept. 22. The scientists, including USGS scientist Jim Estes of the Western Ecological Research Center, believe that when great whales became scarce, their foremost natural predators, killer whales, turned to other marine mammals as primary sources of food, causing sequential declines in southwest Alaska during the 1960s and 1970s of first the harbor seals, followed by northern fur seals, Steller sea lions and finally, in the 1990s, sea otters, as killer whales “fished down” the food web. Citation: Springer, A.M., J. A. Estes, G. B. van Vliet, T. M. Williams, D. F. Doak, E. M. Danner, K. A. Forney, and B. Pfister. 2003. Sequential megafaunal collapse in the North Pacific Ocean: an ongoing legacy of industrial whaling? (Jim Estes, Santa Cruz, CA, 831-459-2820, jim_estes@usgs.gov)

Forests and Greenhouse Gas Fluxes: On September 24, USGS scientist Nate Stephenson of the Western Ecological Research Center will be an invited speaker at a National Research Council workshop on "Direct and Indirect Human Contributions to Terrestrial Greenhouse Gas Fluxes" in Washington, D.C. He will speak on the carbon dynamics of forests, including effects of climate and fire. (Nate Stephenson, Three Rivers, CA, 559-565-3176, nstephenson@usgs.gov)

Restoring Native Ecosystems: USGS scientist Jon Keeley of the Western Ecological Research Center will give an invited talk titled "Natural and Managed Role of Fire in Shrubland and Grassland Restoration" at the 10th annual conference of the California Society for Ecological Restoration (SERCAL) in Asilomar, California on Sept. 29. The talk is part of a symposium on "Issues in Restoration of Two California Habitats: Coastal Sage Scrub and Grasslands." Within the mediterranean-climate region of California and adjacent regions invasive plants are largely concentrated in the lower elevation valleys and foothills. Fire has historically been an important part of the ecology of many of these ecosystems; however, anthropogenic disruptions of natural fire regimes have contributed to the widespread invasion of certain communities. Keeley will discuss the complex challenges of restoring these native systems when the use of prescription burning and other practices may hinder the restoration of native species and promote and perpetuate the dominance of invasives. For more information: http://www.sercal.org/2003_conference.htm. (Jon Keeley, Three Rivers, CA, 559-565-3170, jon_keeley@usgs.gov)

Island Plants: USGS botanist Matthew Barmann of the Western Ecological Research Center presented a seminar on a vegetation inventory recently completed on Santa Cruz Island to an Environmental Biology class at Santa Barbara City College, Santa Barbara, Calif., on Sept 16. (Kathryn McEachern, Ventura, CA, 805-658-5753, kathryn_mceachern@usgs.gov)

After the Fire: On a two-day pack trip into the Sierra Nevada, hosted by the Los Angeles Times, USGS fire ecologist Jon Keeley of the Western Ecological Research Center will be interviewed along with other invitees in a diverse group representing different perspectives on how to manage postfire environments. The group will examine the McNally Fire area in Rattlesnake Canyon of the Sequoia National Forest. (Jon Keeley, Three Rivers, CA, 559-565-3170, jon_keeley@usgs.gov)

Snowy Plover Conservation Effort Recognition: Four individuals leading an effort to balance recreation and protection of snowy plovers will receive the Natural Areas Association 2003 Resource Stewardship award during the national meeting of the organization, Sept. 24-27, 2003, in Madison, Wisconsin. The recipients are Cristina Sandoval of the University of California Natural Reserve System, Jennifer Stroh and Kendy Radasky of Santa Barbara Audubon, and USGS scientist Kevin Lafferty of the Western Ecological Research Center. Their experimental rope barrier redirecting foot traffic from principal plover roost and nesting areas on Coal Oil Point Reserve combined with an education effort and the help of volunteers has resulted in the first plover fledglings on this stretch of beach since before the opening of the reserve in 1970. Lafferty will also give a paper during the conference on “Parasites of snails as indicators of estuarine bird communities.” He will discuss the use of trematode communities having California horn snails as first hosts and various species of coastal wetland birds as last hosts to assess bird diversity in wetlands. For more information: http://www.naturalarea.org/. (Kevin Lafferty, Santa Barbara, CA, Santa Barbara, CA, 805-893-8778, klafferty@usgs.gov)

Turtle and Tortoise Conservation: USGS scientist Kristin Berry of the Western Ecological Research Center is an invited speaker at the California Turtle and Tortoise Club's Symposium 2003 on the Current Conservation of Turtles and Tortoises, Public and Private Efforts, to be held in Carson, California on Sept. 5-7. Berry’s talk on Sept. 6 is titled “The continued declining trends in desert tortoise populations in California between 1979 and 2002: multiple issues.” For more information: http://www.turtleconference.org/. (Kristin Berry, Moreno Valley, CA, 909-697-5361, kristin_berry@usgs.gov)

Tortoises: USGS scientist Kristin Berry of the Western Ecological Research Center was interviewed about the lives of desert tortoises for a children’s novel (age 11-15) in an environment series on threatened and endangered species. (Kristin Berry, Moreno Valley, CA, 909-697-5361, kristin_berry@usgs.gov)

Aliens and Fire: USGS scientist Jon Keeley of the Western Ecological Research Center was interviewed by United Press International about the effect of alien grasses on fire regimes in California. (Jon Keeley, Three Rivers, CA, 559-565-3170, jon_keeley@usgs.gov)

MSCP Video: USGS scientists Melanie Madden-Smith and Ed Ervin of the Western Ecological Research Center were filmed conducting monitoring work on turtles and toads as part of a video of the County of San Diego that will profile the Multiple Species Conservation Program and county parks and air on County Television Network. (Melanie Madden-Smith, San Diego, CA, 858-637-6907, mmaddensmith@usgs.gov; Ed Ervin, San Diego, CA, 858-637-6890, eervin@usgs.gov)