WERC Highlights -- August 2005

Remembering the Vision Fire: Scientist Gary Fellers of the USGS Western Ecological Research Center will be a speaker at the Fire in the Ecosystem Seminar presented at Point Reyes National Seashore, September 17, 2005. The seminar is one of the 10-year anniversary events remembering the Vision Fire (1995-2005), a 5,000-hectare wildlands fire on the Point Reyes peninsula, California. Fellers will discuss how the fire affected wildlife at Point Reyes, focusing on mammals and amphibians, with special attention to rare, endemic Point Reyes mountain beavers especially hard hit by the fire. For more: http://www.nps.gov/pore/pphtml/events.html (Gary Fellers, Point Reyes, CA, 415-464-5185, gary_fellers@usgs.gov)

Aquatic Science: USGS scientist Chris Currens of the Western Ecological Research Center will present two posters at the American Fisheries Society 135th annual meeting in Anchorage, Alaska, Sept. 11-15, 2005. One poster is on impacts of watershed restoration and road decommissioning on tailed frogs in Redwood National and State Parks. Tailed frogs are sensitive to disturbance and can be indicators of suitable stream conditions for several vertebrate species. In this study, significantly higher biomass of larval tailed frogs was found in low-disturbed versus moderately and highly disturbed stream reaches, and individual larval frogs were larger in low-disturbed than in moderately or highly disturbed reaches. Currens will also present a poster on another study, an enclosure experiment in which the presence of brook trout that are too small to consume northwestern salamanders were found to have a negative effect on salamander behavior and growth, but fish density did not have an effect; and that trout stocking in high-elevation lakes may not be compatible with salamander population persistence. For more: http://www.wdafs.org/Anchorage2005/index.htm. (Chris Currens, Arcata, CA, 707-825-5189, ccurrens@usgs.gov)

Cheatgrass Research: A fire success story on the NPS Fire and Aviation Management web site (under Public and Media fire stories for 2005) titled “Using Science to ‘Cheat’ Cheatgrass” describes the effort by fire managers at Sequoia and Kings Canyon National Parks and scientists at the USGS Western Ecological Research Center to better understand how cheatgrass and fire interact, to discover if prescribed burns in these parks can be conducted in such a manner as to control the spread of cheatgrass. Research indicated that less frequent fires (to allow a buildup of a couple of inches of pine needles) in cooler conditions, to create less intense fires, might best limit cheatgrass in these forests. For more: http://data2.itc.nps.gov/fire/index.cfm; http://www.nps.gov/fire/public/pubs_fir05_seki_cheatgrass.html. (Jon Keeley, Three Rivers, CA, 559-565-3170, jon_keeley@usgs.gov)

Salt Ponds: An August 27, 2005 story in the San Mateo Daily Journal reported on science support the U.S. Geological Survey is providing for the wetland restoration of former commercial salt ponds in the San Francisco Bay. At a USGS public lecture (Aug. 25), USGS scientists A. Keith Miles and John Takekawa described the data being collected from each pond. Miles was quoted in the story on the magnitude of the project and importance of the science support to planning the appropriate habitat for wildlife: http://www.smdailyjournal.com/article_preview.php?id=47967. (A. Keith Miles, Davis, CA, 530-752-5365, keith_miles@usgs.gov; John Takekawa, Vallejo, CA, 707-562-2000, john_takekawa@usgs.gov)

Exploring Individual Quality in Seabirds: Despite much evidence that some birds achieve both superior reproductive performance and higher survivorship, the factors underlying an individual’s quality are not well understood. In a recent publication in the journal Behavioral Ecology, USGS scientist Josh Ackerman (a post-doctoral researcher at the University of California, Davis, at the time of this study) and coauthors from several universities studied Leach's storm-petrels breeding on Kent Island, New Brunswick, Canada, to examine whether basal metabolic rate influences an individual’s quality. The researchers found that males with relatively low metabolic rates hatched their eggs earlier in the season and that their chicks' wing growth rates were faster compared to males with relatively high metabolic rates. Conversely, metabolic rate was not related to reproductive performance of females. Their results suggest that male, but not female, storm-petrels with lower basal metabolic rates achieve better reproductive performance because they have lower self-maintenance costs and therefore can apportion more energy to reproduction. (Josh Ackerman, Davis, CA, 530-752-0485, jackerman@usgs.gov) Citation: Blackmer, A. L., R. A. Mauck, J. T. Ackerman, C. E. Huntington, G. A. Nevitt, and J. B. Williams. 2005. Exploring individual quality: basal metabolic rate and reproductive performance in Leach’s storm-petrels. Behavioral Ecology 16: 906–913.

Temperature and Cholinesterase Activity in Pacific Tree Frogs: Lower cholinesterase activity in Pacific tree frog (Hylla regilla) tadpoles from the Sierra Nevada versus those of the same species from coastal locations has been attributed to the presence of organophosphate insecticides. These frogs are used as a model to help scientists assess pesticide exposure for amphibians within the Sierra Nevada, where wind-transported organophosphate pesticides from agricultural areas have been hypothesized as playing a role in amphibian declines. Water temperatures differ between coastal and Sierran locations of the tree frog and temperature may produce differences in cholinesterase activity independent of pesticide exposure. Temperature effects may be an important factor in assessing pesticide exposure in frogs, according to a study in the August issue of the journal Environmental Toxicology and Chemistry by USGS scientist Steve Schwarzbach, center director of the Western Ecological Research Center, and coauthors at the U.S. Fish and Wildlife Service and University of California, Davis. In a laboratory experiment, the scientists collected Pacific tree frogs from a coastal and Sierran location and reared them in groups at coastal temperature (19oC) and Sierran temperature (8oC). Regardless of origin, cholinesterase activity in tadpoles reared at the coastal temperature was significantly higher than in tadpoles raised at the Sierran temperature. When coastal or Sierran tadpoles were raised at the same temperature, there was no significant difference in cholinesterase activity between frogs from the two locations. The authors suggest that future research should include laboratory experiments with both pesticides and temperatures and the development of temperature and pesticide response curves for assessing the true meaning of the cholinesterase biomarker in tree frogs. (Steve Schwarzbach, Sacramento, CA, 916- 278-9490, steven_schwarzbach@usgs.gov) Citation: Johnson, C. S., S. E. Schwarzbach, J. D. Henderson, B. W. Wilson, and R. S. Tjeerdema. 2005. Influence of Water Temperature on Acetylcholinesterase Activity in the Pacific Tree Frog (Hyla regilla). Environmental Toxicology and Chemistry 24(8):2074-2077.

Arroyo Toads Hanging Tough: Despite last winter's heavy rains upon a landscape still recovering from an extensive wildfire, the arroyo toads of Cuyamaca Rancho State Park are exhibiting an expanded distribution. USGS scientists from the Western Ecological Research Center surveyed the Sweetwater River this summer to continue monitoring the federally endangered toad's response to the 2003 Cedar Fire in San Diego County, California, and the potentially-subsequent habitat changes. Arroyo toad recruitment has been documented in successively greater distributions over the last four years, 2002-03 (pre-fire), 2004, and now 2005. In related news, WERC scientist Mark Mendelsohn's presentation about the 2004 survey results can be viewed in a recent DVD release from the Anza-Borrego Institute (http://theabf.org) and California State Parks entitled "The Cedar Fire and Cuyamaca Rancho State Park One Year Later," which includes several presentations covering the effects of the fire on the park's natural, cultural, and historical resources. (Mark Mendelsohn, San Diego, CA, 858-637-6888, mmendelsohn@usgs.gov)

Rare Plant: An August 11, 2005, story in the Orange County Register on a first sighting of Jepson's California broomrape in Orange County. Scientist Alison Colwell of the USGS Western Ecological Research Center, who studies rare plants at Yosemite National Park, was interviewed for the story, which mentions her broomrape expertise. For more: http://www.ocregister.com/ocr/2005/08/11/sections/local/local/article_630798.php (Alison Colwell, El Portal, CA, 206-526-6282 x329, alison_colwell@usgs.gov)

Invasive Sahara Mustard Is Focus of Desert Managers Group Workshop: The Desert Managers Group will bring together scientists and resource managers to discuss the state-of-knowledge of Sahara mustard (Brassica tournefortii) in the desert Southwest and guide the effective development of regional control programs and new research. Record winter rainfall in the region during 2004-2005 boosted the production of this widespread coarse annual, increasing concern for its potential ecological effects. Along with nonnative grass invaders this annual mustard can contribute to an increase in fire hazard and displace native plants that are important to wildlife, such as the threatened Mojave Population of the desert tortoise. Scientist Matt Brooks of the USGS Western Ecological Research Center is a co-organizer of the workshop and will give a presentation on the invasion history of this species and compare with the invasion histories other nonnative mustards. The workshop will be held August 30, 2005, in Lenwood, Calif. The Desert Managers Group is a forum for government agencies to address and discuss issues of common concern. For more: http://www.dmg.gov/workshops/smwsindex.php. (Matt Brooks, Henderson, NV, 702-564-4615, matt_brooks@usgs.gov)

Avian Research: Scientists from the USGS Western Ecological Research Center are participating in the 123rd Stated Meeting of the American Ornithologists’ Union to be held August 23-27, 2005, at the University of California, Santa Barbara. USGS scientist Kevin Lafferty is co-organizer of a symposium titled “Parasite effects on birds at individual and population levels,” on the ecology and evolution of birds and parasitism. To set the stage, Lafferty will discuss the complex life cycle of trematodes that use birds as final hosts and how these parasites and their bird hosts dominate the food web of a local estuary. USGS scientist Barbara Kus is co-organizer of the symposium “Avian conservation in western riparian ecosystems” and will present data on the response of the endangered Least Bell's Vireo to discontinuation of cowbird control. Additionally of interest is a plenary presentation and field trip highlighting the successful cooperative conservation effort to restore nesting western snowy plovers to a local public beach; USGS provided science support for this conservation effort. For more: http://www.aou.org/2005meeting/. (Kevin Lafferty, Santa Barbara, CA, 805-893-8778, klafferty@usgs.gov; Barbara Kus, San Diego, CA, 858-637-6881, barbara_kus@usgs.gov)

A Delicate Balance: On August 25, 2005, scientists A. Keith Miles and John Takekawa of the USGS Western Ecological Research Center will present “A Delicate Balance: Salt Ponds, Wetland Restoration, and Wildlife in San Francisco Bay” at the USGS evening public lecture in Menlo Park, California. Nearly 15,000 acres of San Francisco Bay salt ponds were purchased in 2003 for restoration by a partnership of federal, state, and nonprofit organizations. Miles and Takekawa will discuss the many challenges of wetland restoration in this most urbanized estuary of the Nation. They will discuss questions their research seeks to help answer, such as: How important are the salt ponds for migration and wintering of waterfowl and shorebirds? Will it be possible to manage concentrated salts, low dissolved oxygen, and toxicity of sequestered mercury as pond levees are opened? How difficult will it be to control invasive species, such as smooth cord grass, while restoring wetlands? For more: http://online.wr.usgs.gov/calendar/. (A. Keith Miles, Davis, CA, 530-752-5365, keith_miles@usgs.gov; John Takekawa, Vallejo, CA, 707- 562-2000, john_takekawa@usgs.gov)

Tree Populations, Present and Future: In a study published in the Journal of Ecology, USGS scientists Phil van Mantgem and Nate Stephenson of the Western Ecological Research Center tested the accuracy of models commonly used in population viability analyses for trees in the Sierra Nevada of California. These analyses, which inform conservation policy and strategies, often rely on population models that extrapolate relatively short-term demographic data decades into the future. Using a unique long-term data set from Sequoia and Yosemite national parks, the authors used demographic data from six coniferous tree species, encompassing 16,673 trees in 15 permanent plots, to create 17 separate simple matrix population models based on tree stem size. Using these models they determined differences between projected trends from initial 5-year records and observed data during two subsequent 5-year time steps. Projected tree population size was well predicted by simple models; short-term predictions of survival, growth, and recruitment were much more accurate than mortality. The authors advised that the success of these models can be largely attributed to the fact that demographic rates appeared to be relatively stable in the absence of disturbance. For more: http://www.werc.usgs.gov/pubbriefs/vanmantgempbaug2005.html. Citation: van Mantgem, P. J., and N. L. Stephenson. 2005. The accuracy of matrix population model projections for coniferous trees in the Sierra Nevada. Journal of Ecology 93: 737-747.