Publications
Below is a list of WERC's peer-reviewed publications. If you are searching for a specific publication and cannot find it in this list, please contact werc_web@usgs.gov
Filter Total Items: 3618
Postfire chaparral regeneration under mediterranean and non-mediterranean climates
This study compares postfire regeneration and diversity patterns in fire-prone chaparral shrublands from mediterranean (California) and non-mediterranean-type climates (Arizona). Vegetation sampling was conducted in tenth hectare plots with nested subplots for the first two years after fire. Floras in the two regions were compared with Jaccard's Index and importance of families and genera compared
Authors
Jon E. Keeley, Connie J. Fotheringham, Philip W. Rundel
Fire-driven alien invasion in a fire-adapted ecosystem
Disturbance plays a key role in many alien plant invasions. However, often the main driver of invasion is not disturbance per se but alterations in the disturbance regime. In some fire-adapted shrublands, the community is highly resilient to infrequent, high-intensity fires, but changes in the fire regime that result in shorter fire intervals may make these communities more susceptible to alien pl
Authors
Jon E. Keeley, Teresa J. Brennan
Ecological consequences of manipulative parasites
This chapter considers the context in which manipulative parasites could have noticeable ecological effects. By this, we mean that a manipulation of a host that benefits a parasite can also indirectly affect other non-hosts in the system, sometimes in dramatic fashion. Such ecosystem-level changes could occur for manipulative parasites that have a strong effect on their host, a high rate of infect
Authors
Kevin D. Lafferty, A. M. Kuris, Michel Loreau
California spotted owls
California spotted owls (Strix occidentalis occidentalis) are habitat specialists that are strongly associated with late-successional forests. For nesting and roosting, they require large trees and snags embedded in a stand with a complex forest structure (Blakesley et al. 2005, Gutiérrez et al. 1992, Verner et al. 1992b). In mixed-conifer forests of the Sierra Nevada, California spotted owls typi
Authors
Suzanne C. Roberts, M. North
Foraging segregation and genetic divergence between geographically proximate colonies of a highly mobile seabird
Foraging segregation may play an important role in the maintenance of animal diversity, and is a proposed mechanism for promoting genetic divergence within seabird species. However, little information exists regarding its presence among seabird populations. We investigated genetic and foraging divergence between two colonies of endangered Hawaiian petrels (Pterodroma sandwichensis) nesting on the
Authors
Anne E. Wiley, Andreanna J. Welch, P.H. Ostrom, Helen F. James, Craig A. Stricker, R.C. Fleischer, H. Gandhi, Josh Adams, D. G. Ainley, F. Duvall, N. Holmes, D. Hu, S. Judge, J. Penniman, K.A. Swindle
A plant distribution shift: temperature, drought or past disturbance?
Simple models of plant response to warming climates predict vegetation moving to cooler and/or wetter locations: in mountainous regions shifting upslope. However, species-specific responses to climate change are likely to be much more complex. We re-examined a recently reported vegetation shift in the Santa Rosa Mountains, California, to better understand the mechanisms behind the reported shift o
Authors
Dylan W. Schwilk, Jon E. Keeley
Gene transcription in sea otters (Enhydra lutris); development of a diagnostic tool for sea otter and ecosystem health
Gene transcription analysis for diagnosing or monitoring wildlife health requires the ability to distinguish pathophysiological change from natural variation. Herein, we describe methodology for the development of quantitative real-time polymerase chain reaction (qPCR) assays to measure differential transcript levels of multiple immune function genes in the sea otter (Enhydra lutris); sea otter-sp
Authors
Lizabeth Bowen, A. Keith Miles, Michael Murray, Martin Haulena, Judy Tuttle, William van Bonn, Lance Adams, James L. Bodkin, Brenda E. Ballachey, James A. Estes, M. Tim Tinker, Robin Keister, Jeffrey L. Stott
Supplementing seed banks to rehabilitate disturbed Mojave Desert shrublands: Where do all the seeds go?
Revegetation of degraded arid lands often involves supplementing impoverished seed banks and improving the seedbed, yet these approaches frequently fail. To understand these failures, we tracked the fates of seeds for six shrub species that were broadcast across two contrasting surface disturbances common to the Mojave Desert—sites compacted by concentrated vehicle use and trenched sites where top
Authors
Lesley A. DeFalco, Todd C. Esque, Melissa B. Nicklas, Jeffrey M. Kane
Seed dispersal and seed fate in Joshua tree (Yucca brevifolia)
Joshua tree (Yucca brevifolia) is a charismatic symbol of the Mojave Desert. Despite its familiarity, we know little about the reproduction of this species, including mechanisms of seed dispersal. Here we examine mechanisms of seed dispersal and resulting seed fate. We experimentally tracked fruit and seed removal and followed the fates of Joshua tree seeds using radioactive tracers. The majority
Authors
B.A. Waitman, S.B. Vander Wall, Todd C. Esque
Wetlands of the Central Valley of California and Klamath Basin
No abstract available.
Authors
Joseph P. Fleskes
Migration strategy affects avian influenza dynamics in mallards (Anas platyrhynchos).
Studies of pathogen transmission typically overlook that wildlife hosts can include both migrant and resident populations when attempting to model circulation. Through the application of stable isotopes in flight feathers, we estimated the migration strategy of mallards (Anas platyrhynchos) occurring on California wintering grounds. Our study demonstrates that mallards- a principal host of avian i
Authors
John Y. Takekawa, Nichola J. Hill, Joshua T. Ackerman, Garth Herring, Keith Hobson, Carol J. Cardona, Jonathan Runstadler, Walter M. Boyce
Mercury exposure may suppress baseline corticosterone levels in juvenile birds
Mercury exposure has been associated with a wide variety of negative reproductive responses in birds, however few studies have examined the potential for chick impairment via the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis regulates corticosterone levels during periods of stress. We examined the relationship between baseline fecal corticosterone metabolite concentrations and mercury co
Authors
Garth Herring, Joshua T. Ackerman, Mark P. Herzog