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Publications

Below are publications associated with the Southwest Biological Science Center's research.

If you are unable to access or download a product after you've clicked through the links below, email mhartwell@usgs.gov with your request. Please include the citation in your email and/or a link to the product. Note that each product has several link options once you click on the title.

Filter Total Items: 1342

Nest guarding by female Agassiz's desert tortoise (Gopherus agassizii) at a wind-energy facility near Palm Springs, California

We observed behavior consistent with nest-guarding in Agassiz's desert tortoise (Gopherus agassizii) at two nests in a large wind-energy-generation facility near Palm Springs, California, locally known as the Mesa Wind Farm. As researchers approached the nests, female desert tortoises moved to the entrance of their burrows and positioned themselves sideways, directly over their nests. One female s
Authors
Mickey Agha, Jeffrey E. Lovich, Joshua R. Ennen, Ethan Wilcox

Food-web dynamics in a large river discontinuum

Nearly all ecosystems have been altered by human activities, and most communities are now composed of interacting species that have not co-evolved. These changes may modify species interactions, energy and material flows, and food-web stability. Although structural changes to ecosystems have been widely reported, few studies have linked such changes to dynamic food-web attributes and patterns of e
Authors
Wyatt F. Cross, Colden V. Baxter, Emma J. Rosi-Marshall, Robert O. Hall, Theodore A. Kennedy, Kevin C. Donner, Holly A. Wellard Kelly, Sarah E.Z. Seegert, Kathrine E. Behn, Michael D. Yard

Consumption of seeds of southwestern white pine (Pinus strobiformis) by Black Bear (Ursus americanus)

We report a discovery of black bears (Ursus americanus) consuming seeds of southwestern white pine (Pinus strobiformis) on north slopes of the San Francisco Peaks near Flagstaff, Arizona, in high-elevation, mixed-species conifer forest. In one instance, a bear had obtained seeds from cones excavated from a larder horde made by a red squirrel (Tamiasciurus hudsonicus). Consumption of seeds of south
Authors
David J. Mattson, Terry A. Arundel

Plot- and landscape-level changes in climate and vegetation following defoliation of exotic saltcedar (Tamarix sp.) from the biocontrol agent Diorhabda carinulata along a stream in the Mojave Desert (USA)

The biocontrol agent, northern tamarisk beetle (Diorhabda carinulata), has been used to defoliate non-native saltcedar (Tamarix spp.) in USA western riparian systems since 2001. Biocontrol has the potential to impact biotic communities and climatic conditions in affected riparian areas. To determine the relationships between biocontrol establishment and effects on vegetation and climate at the plo
Authors
H.L. Bateman, Pamela L. Nagler, E.P. Glenn

Ecological impacts of energy-wood harvests: Lessons from whole-tree harvesting and natural disturbance

Recent interest in using forest residues and small-diameter material for biofuels is generating a renewed focus on harvesting impacts and forest sustainability. The rich legacy of research from whole-tree harvesting studies can be examined in light of this interest. Although this research largely focused on consequences for forest productivity, in particular carbon and nutrient pools, it also has
Authors
Alaina L. Berger, Brian Palik, Anthony W. D'Amato, Shawn Fraver, John B. Bradford, Keith H. Nislow, David King, Robert T. Brooks

Natural-color and color-infrared image mosaics of the Colorado River corridor in Arizona derived from the May 2009 airborne image collection

The Grand Canyon Monitoring and Research Center (GCMRC) of the U.S. Geological Survey (USGS) periodically collects airborne image data for the Colorado River corridor within Arizona (fig. 1) to allow scientists to study the impacts of Glen Canyon Dam water release on the corridor’s natural and cultural resources. These data are collected from just above Glen Canyon Dam (in Lake Powell) down to the
Authors
Philip A. Davis

Home range characteristics and overwintering ecology of the stripe-necked musk turtle (Sternotherus minor peltifer) in middle Tennessee

Little is known about the movement behavior of the stripe-necked musk turtle, Sternotherus minor peltifer. Using radiotelemetry, we calculated mean (± SD) home range length, which was 341.4 ± 90.3 m, with home range length not differing between the sexes (males, 335 ± 194 m; females, 346 ± 79.5 m). Sternotherus m. peltifer were active in every month of the year but decreased their movement distanc
Authors
Joshua R. Ennen, A. Floyd Scott

Natural ecosystems

Natural Ecosystems analyzes the association of observed changes in climate with changes in the geographic distributions and phenology (the timing of blossoms or migrations of birds) for Southwestern ecosystems and their species, portraying ecosystem disturbances—such as wildfires and outbreaks of forest pathogens—and carbon storage and release, in relation to climate change.
Authors
Erica Fleishman, Jayne Belnap, Neil Cobb, Carolyn A.F. Enquist, Karl Ford, Glen MacDonald, Mike Pellant, Tania Schoennagel, Lara M. Schmit, Mark Schwartz, Suzanne van Drunick, Anthony LeRoy Westerling, Alisa Keyser, Ryan Lucas

Biological nitrogen fixation: rates, patterns and ecological controls in terrestrial ecosystems

New techniques have identified a wide range of organisms with the capacity to carry out biological nitrogen fixation (BNF)—greatly expanding our appreciation of the diversity and ubiquity of N fixers—but our understanding of the rates and controls of BNF at ecosystem and global scales has not advanced at the same pace. Nevertheless, determining rates and controls of BNF is crucial to placing anthr
Authors
Peter M. Vitousek, Duncan N.L. Menge, Sasha C. Reed, Cory C. Cleveland

Potential climate change impacts on temperate forest ecosystem processes

Large changes in atmospheric CO2, temperature and precipitation are predicted by 2100, yet the long-term consequences for carbon, water, and nitrogen cycling in forests are poorly understood. We applied the PnET-CN ecosystem model to compare the long-term effects of changing climate and atmospheric CO2 on productivity, evapotranspiration, runoff, and net nitrogen mineralization in current Great La
Authors
Emily B. Peters, Kirk R. Wythers, Shuxia Zhang, John B. Bradford, Peter B. Reich

Native and nonnative fish populations of the Colorado River are food limited--evidence from new food web analyses

Fish populations in the Colorado River downstream from Glen Canyon Dam appear to be limited by the availability of high-quality invertebrate prey. Midge and blackfly production is low and nonnative rainbow trout in Glen Canyon and native fishes in Grand Canyon consume virtually all of the midge and blackfly biomass that is produced annually. In Glen Canyon, the invertebrate assemblage is dominated
Authors
Theodore A. Kennedy, Wyatt F. Cross, Robert O. Hall, Colden V. Baxter, Emma J. Rosi-Marshall

Linking morphodynamic response with sediment mass balance on the Colorado River in Marble Canyon: issues of scale, geomorphic setting, and sampling design

Measurements of morphologic change are often used to infer sediment mass balance. Such measurements may, however, result in gross errors when morphologic changes over short reaches are extrapolated to predict changes in sediment mass balance for long river segments. This issue is investigated by examination of morphologic change and sediment influx and efflux for a 100 km segment of the Colorado R
Authors
Paul E. Grams, David J. Topping, John C. Schmidt, Joseph E. Hazel, Matt Kaplinski
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