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Los Gatos, CA, United States

Demers S.A.,U.S. Geological Survey | Demers S.A.,983 University Ave | Takekawa J.Y.,U.S. Geological Survey | Ackerman J.T.,U.S. Geological Survey | And 3 more authors.
Condor | Year: 2010

San Francisco Bay is a wintering area for shorebirds, including American Avocets (Recurvirostra americana). Recently, a new resident population of avocets has emerged, presumably because of the development of tidal marshes into salt-evaporation ponds. In habitat restoration now underway, as many as 90% of salt ponds will be restored to tidal marsh. However, it is unknown if wintering and resident avocets coexist and if their requirements for space and habitat differ, necessitating different management for their populations to be maintained during restoration. We captured and radio-marked wintering avocets at a salt pond and a tidal flat to determine their population status (migrant or resident) and examine their space use and habitat selection. Of the radio-marked avocets, 79% were migrants and 21% were residents. At the salt pond, residents' fidelity to their location of capture was higher, and residents moved less than did migrants from the same site. Conversely, on the tidal flat, fidelity of residents to their site of capture was lower, and residents' home ranges were larger than those of migrants from the same site. Habitat selection of migrants and residents differed little; however, capture site influenced habitat selection far more than the birds' status as migrants or residents. Our study suggests that individual avocets have high site fidelity while wintering in San Francisco Bay, although the avocet as a species is plastic in its space use and habitat selection. This plasticity may allow wintering migrant and resident avocets to adapt to habitat change in San Francisco Bay. © The Cooper Ornithological Society 2010. Source


Takekawa J.Y.,U.S. Geological Survey | Woo I.,U.S. Geological Survey | Athearn N.D.,U.S. Geological Survey | Athearn N.D.,U.S. Fish and Wildlife Service | And 8 more authors.
Wetlands Ecology and Management | Year: 2010

Sediment accretion is a critical indicator of initial progress in tidal marsh restoration. However, it is often difficult to measure early deposition rates, because the bottom surface is usually obscured under turbid, tidally-influenced waters. To accurately measure early sediment deposition in marshes, we developed an echosounder system consisting of a specialized acoustic profiler, differential global positioning system unit, and laptop computer mounted on a shallow-draft boat. We conducted a bathymetry survey at the Tubbs Setback tidal restoration site on San Pablo Bay, California, along north-south transects at 25-m intervals. Horizontal position was recorded within 1 m each second and water depth to 1 cm every 0.05 s. Bottom elevations were adjusted for tidal height with surveyed tide gages. We created detailed bathymetric maps (grid cell size: 12.5 m × 12.5 m) by interpolation with inverse distance weighting. During the third year after restoration, sediment accretion averaged 57.1 ± 1.1 cm and the estimated sediment gain was 132,900 m3. The mean difference between the elevations from the bathymetry system and the 9 sediment pins was 2.0 ± 1.0 cm. The mean difference of the intersection points of east-west and north-south survey transects was 2.1 ± 0.2 cm, which provided a measure of repeatability with changing water levels. Our echosounder system provided accurate and repeatable measurements of sediment accretion of a recently restored tidal wetland, and this system proved to be a viable tool for determining sediment deposition in marshes and assessing early restoration progress. © 2010 US Government. Source


Alford E.R.,Colorado State University | Alford E.R.,983 University Ave | Lindblom S.D.,Colorado State University | Pittarello M.,Colorado State University | And 8 more authors.
American Journal of Botany | Year: 2014

• Premise of the study: Are there dimensions of symbiotic root interactions that are overlooked because plant mineral nutrition is the foundation and, perhaps too often, the sole explanation through which we view these relationships? In this paper we investigate how the root nodule symbiosis in selenium (Se) hyperaccumulator and nonaccumulator Astragalus species influences plant selenium (Se) accumulation.• Methods: In greenhouse studies, Se was added to nodulated and nonnodulated hyperaccumulator and nonaccumulator Astragalus plants, followed by investigation of nitrogen (N)–Se relationships. Selenium speciation was also investigated, using x-ray microprobe analysis and liquid chromatography–mass spectrometry (LC-MS).• Key results: Nodulation enhanced biomass production and Se to S ratio in both hyperaccumulator and nonaccumulator plants. The hyperaccumulator contained more Se when nodulated, while the nonaccumulator contained less S when nodulated. Shoot [Se] was positively correlated with shoot N in Se-hyperaccumulator species, but not in nonhyperaccumulator species. The xray microprobe analysis showed that hyperaccumulators contain significantly higher amounts of organic Se than nonhyperaccumulators. LC-MS of A. bisulcatus leaves revealed that nodulated plants contained more γ -glutamyl-methylselenocysteine (γ -Glu-MeSeCys) than nonnodulated plants, while MeSeCys levels were similar.• Conclusions: Root nodule mutualism positively affects Se hyperaccumulation in Astragalus. The microbial N supply particularly appears to contribute glutamate for the formation of γ -Glu-MeSeCys. Our results provide insight into the significance of symbiotic interactions in plant adaptation to edaphic conditions. Specifically, our findings illustrate that the importance of these relationships are not limited to alleviating macronutrient deficiencies. © 2014 Botanical Society of America. Source


Carr S.,2801 East 5140 South | Fosdick C.,143 Preston Ave. | Fosdick C.,983 University Ave | Bond R.,2441 Evening Star Drive | And 8 more authors.
Western Birds | Year: 2014

This 19th published report of the Utah Bird Records Committee summarizes 160 records of 71 species reported between 15 June 2010 and 31 December 2012. The committee accepted 134 records. Noteworthy records include four species new to the Utah state list, the Purple Sandpiper (Calidris maritima), Gilded Flicker {Colaptes chrysoides), Tropical Kingbird (Tyrannus melancholicus), and Pyrrhuloxia {Cardinalis sinuatus), which bring the state list to 450 species; the state's second Roseate Spoonbill (Platalea ajaja), Pomarine Jaeger (Stercorarius pomarinus), Curve-billed Thrasher (Toxostoma curvirostre), Canyon Towhee (Melozone fusca), and Northern Cardinal (Cardinalis cardinalis); second, third, and fourth Iceland Gulls (Larus glaucoides); third Prairie Warbler {Setophaga discolor) and Baltimore Oriole (Icterus galbula); and third and fourth Philadelphia Vireos (Vireo philadelphicus). The Cackling Goose (Branta hutchinsii) was removed from the state review list in January 2012 because sufficient documented sightings confirm it is a regular winter visitor to Utah. Source


Nelson K.N.,P.O. Box 402 | Rottenborn S.C.,983 University Ave | Terrill S.B.,983 University Ave
Western Birds | Year: 2013

The California Bird Records Committee reached decisions on 254 records representing 309 individuals of 75 species and three species pairs documented since the 36th report (Johnson et al. 2012), endorsing 210 records of 264 individuals. The recent split of the Xantus's Murrelet into the Scripps's Murrelet (Synthliboramphus scrippsi) and Guadalupe Murrelet (S. hypoleucus), combined with first accepted state records of the Taiga/Tundra Bean-Goose (Anser fabalis/serrirosiris), Common Crane (Grus grus), Common Ringed Plover (Charadrius hiaticula), and Common Snipe (Gallinago gallinago) outlined in this report, brings California's total list of accepted species to 649 as of the end of 2011,10 of which are established introductions. Other notable records detailed in this report include those of the western Atlantic subspecies of the Common Eider (Somateria mollissima dresseri), White-chinned Petrel (Procellaria aequinoctialis), and Red-flanked Bluetail (Tarsiger cyanurus). Source

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