1,009 research outputs found

    Breeding Season Space Use and Habitat Selection of Adult Female Scaled and Gambel\u27s Quail in West Texas

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    We used radiotelemetry to investigate breeding-season (1 Apr–1 Sep, 2012 and 2013) home ranges and habitat selection of adult female scaled (Callipepla squamata) and Gambel’s quail (C. gambelii) in the eastern Chihuahuan Desert, Texas. Mean breeding-season home range (95% fixed kernel) for scaled quail was 145.02 ± 23.56 ha (range = 22.03–538.24 ha) and 156.32 ± 13.04 ha (range = 66.15– 270.74 ha) for Gambel’s quail. Mean core-use area (50% fixed kernel) for scaled quail was 31.38 ± 4.80 ha (range = 4.03–111.36 ha) and 32.87 ± 2.61 ha (range = 12.19–52.36 ha) for Gambel’s quail. We found evidence of home-range overlap in neighboring females in both species. Excessive drought can suppress nesting activity. However, encourage reproductive activity in both species may be encouraged by managing riparian areas to provide adequate forage and microclimatic conditions

    Changes in Habitat Use of Montezuma Quail in Response to Tree Canopy Reduction in the Capitan Mountains of New Mexico

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    Montezuma quail (Cyrtonyx montezumae) are unique among quail with respect to clutch size, diet, covey dynamics, and habitat use. With the exception of a few notable early studies, there is relatively little information on the ecology of Montezuma quail. Pervious research has indicated that one of the primary habitats utilized by Montezuma quail is pinyon–juniper (Pinus spp.–Juniperus spp.) woodlands. Throughout many areas of the southwestern United States, pinyon–juniper woodlands are often targeted for thinning projects. Many studies have been conducted on the amount of canopy cover needed by other quail species. However, data on characteristics of their preferred habitat in many of the mountains they inhabit is limited in the literature and no data are currently published on their response to thinning projects. Therefore, studies are warranted to fill in these missing data, which will increase our knowledge about the habitat requirements of Montezuma quail and allow us to make informed decisions about thinning projects in areas occupied by Montezuma quail. The goal of this research was to evaluate Montezuma quail responses to common silvicultural practices, specifically pinyon–juniper thinning in the Capitan Mountains of New Mexico. Results of our project indicated that Montezuma quail selected for sites that had been thinned to reduce canopy cover to a 30–40% mosaic. Selection for this habitat was much higher than selection for the surrounding area, which consisted of ≥70% canopy cover (Manly–Chesson Selectivity Index = 1.68). Overall, this study yields vital information for managers considering implanting thinning projects in Montezuma quail habitat

    Survival and Nesting Ecology of Scaled Quail in the Trans-Pecos, Texas

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    Scaled quail (Callipepla squamata) are one of the most ecologically and economically important wildlife species in the Trans-Pecos, because they are the primary upland game bird in the Chihuahuan Desert. Using radiotelemetry, we evaluated survival (Kaplan–Meier) and nesting success of quail on 3 study sites in the Trans-Pecos, Texas: one (Santiago Mountain Ranch, central Brewster Co.) was supplemented with milo (Sorghum bicolor) year-round, the second (Lado Ranch, south Culberson Co.) never used supplements, and the third (Apache Ranch, central Culberson Co.) was supplemented with quail blocks. We trapped and radiocollared 164 female quail collectively across all study sites, and followed them for 2 years (May–Sep 2012–2013). There were no survival differences between years within study sites (P = 0.985), so we grouped data across years and compared survival between study sites. Apache Ranch had the lowest survival (55%) compared with the Santiago Mountain Ranch (76.3%) and Lado Ranch (75%). We found 47 nests across the reproductive seasons for 2012 and 2013. On average, scaled quail had high nesting success (72.6%), eggs per nest (11.6), and hatchability (91.25%). Nesting occurred from May to September with peak nesting in June and July. Timing and quantity of rain, combined with range conditions seemed to have the greatest effect on nesting performance

    Atmospheric correction for MASTER image data using localized modelled and observed meteorology and trace gases

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    Atmospheric correction for remote sensing-based studies typically does not use information from spatio-temporally resolved meteorological models. We assessed the effect of using observations and mesoscale weather and chemical transport models on multispectral retrievals of land and ocean properties. We performed two atmospheric corrections on image data acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS)/Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) airborne simulator over Monterey Bay, California. One correction used local atmospheric profiles of meteorology and trace gases at overpass and the other used the 1976 US Standard default atmospheric profile in the MODTRAN4 radiative transfer model.We found only minor impacts from atmospheric correction in the Fluorescence Line Height index of ocean chlorophyll, but substantive differences in retrievals of surface temperature and the Normalized Difference Vegetation Index. Improvements in sea surface temperature retrieval were validated by in situ measurements. Results indicate that spatio-temporally specific atmospheric correction factors from mesoscale models can improve retrievals of surface properties from remotely sensed image data

    Histopathological Analysis of Quails in the Trans-Pecos Ecoregion of Texas

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    Quail populations in Texas, USA, have declined over the past few decades due primarily to habitat loss. The role that parasites may play in such declines has been a recent topic of concern. To help address this question, we collected 12 scaled quail (Callipepla squamata), 8 Gambel’s quail (Callipepla gambelii), and 3 Montezuma quail (Cyrtonyx montezumae) from across the Trans-Pecos ecoregion of Texas via hunter harvest, funnel traps, and night netting. Quail samples were necropsied to determine the abundance of eyeworms (Oxyspirura petrowi). Histopathological analyses were conducted on quail eyeballs and periocular tissues to gain information on parasite-related tissue damage and document other pathogenic factors. We calculated mean abundances of Oxyspirura petrowi for sampled scaled (x̄ = 5.5, standard deviation [SD] = 2.5, x̃ = 3, n = 12), Gambel’s (x̄ = 6.4, SD = 4.2, x̃ = 1.5, n = 8), and Montezuma quail (x̄ = 13, SD = 1.5, x̃ = 13, n = 3). Host tissues exhibited immune responses (i.e., lymphocytic conjunctivitis and plasmacytic adenitis) to O. petrowi. The observed immune responses indicated relatively mild irritation within the ocular tissues. It has been speculated that such irritation to ocular tissues could negatively impact quail vision. This potential impact is worth noting because quails rely on keen vision to detect predators. Future research should focus on measuring the effects of O. petrowi infections on quail survival

    Marine wild-capture fisheries after nuclear war

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    Unidad de excelencia María de Maeztu CEX2019-000940-MIdentificadors digitals: Digital object identifier for the 'European Research Council' (http://dx.doi.org/10.13039/501100000781) Digital object identifier for 'Horizon 2020' (http://dx.doi.org/10.13039/501100007601) - BIGSEA projectNuclear war, beyond its devastating direct impacts, is expected to cause global climatic perturbations through injections of soot into the upper atmosphere. Reduced temperature and sunlight could drive unprecedented reductions in agricultural production, endangering global food security. However, the effects of nuclear war on marine wild-capture fisheries, which significantly contribute to the global animal protein and micronutrient supply, remain unexplored. We simulate the climatic effects of six war scenarios on fish biomass and catch globally, using a state-of-the-art Earth system model and global process-based fisheries model. We also simulate how either rapidly increased fish demand (driven by food shortages) or decreased ability to fish (due to infrastructure disruptions), would affect global catches, and test the benefits of strong prewar fisheries management. We find a decade-long negative climatic impact that intensifies with soot emissions, with global biomass and catch falling by up to 18 ± 3% and 29 ± 7% after a US-Russia war under business-as-usual fishing-similar in magnitude to the end-of-century declines under unmitigated global warming. When war occurs in an overfished state, increasing demand increases short-term (1 to 2 y) catch by at most ∼30% followed by precipitous declines of up to ∼70%, thus offsetting only a minor fraction of agricultural losses. However, effective prewar management that rebuilds fish biomass could ensure a short-term catch buffer large enough to replace ∼43 ± 35% of today's global animal protein production. This buffering function in the event of a global food emergency adds to the many previously known economic and ecological benefits of effective and precautionary fisheries management

    Marine wild-capture fisheries after nuclear war

    Get PDF
    Nuclear war, beyond its devastating direct impacts, is expected to cause global climatic perturbations through injections of soot into the upper atmosphere. Reduced temperature and sunlight could drive unprecedented reductions in agricultural production, endangering global food security. However, the effects of nuclear war on marine wild-capture fisheries, which significantly contribute to the global animal protein and micronutrient supply, remain unexplored. We simulate the climatic effects of six war scenarios on fish biomass and catch globally, using a state-of-the-art Earth system model and global process-based fisheries model. We also simulate how either rapidly increased fish demand (driven by food shortages) or decreased ability to fish (due to infrastructure disruptions), would affect global catches, and test the benefits of strong prewar fisheries management. We find a decade-long negative climatic impact that intensifies with soot emissions, with global biomass and catch falling by up to 18 ± 3% and 29 ± 7% after a US–Russia war under business-as-usual fishing—similar in magnitude to the end-of-century declines under unmitigated global warming. When war occurs in an overfished state, increasing demand increases short-term (1 to 2 y) catch by at most ∼30% followed by precipitous declines of up to ∼70%, thus offsetting only a minor fraction of agricultural losses. However, effective prewar management that rebuilds fish biomass could ensure a short-term catch buffer large enough to replace ∼43 ± 35% of today’s global animal protein production. This buffering function in the event of a global food emergency adds to the many previously known economic and ecological benefits of effective and precautionary fisheries management

    GaSbBi alloys and heterostructures: fabrication and properties

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    International audienceDilute bismuth (Bi) III-V alloys have recently attracted great attention, due to their properties of band-gap reduction and spin-orbit splitting. The incorporation of Bi into antimonide based III-V semiconductors is very attractive for the development of new optoelectronic devices working in the mid-infrared range (2-5 µm). However, due to its large size, Bi does not readily incorporate into III-V alloys and the epitaxy of III-V dilute bismides is thus very challenging. This book chapter presents the most recent developments in the epitaxy and characterization of GaSbBi alloys and heterostructures

    The Sensitivity of HAWC to High-Mass Dark Matter Annihilations

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    The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view detector sensitive to gamma rays of 100 GeV to a few hundred TeV. Located in central Mexico at 19 degrees North latitude and 4100 m above sea level, HAWC will observe gamma rays and cosmic rays with an array of water Cherenkov detectors. The full HAWC array is scheduled to be operational in Spring 2015. In this paper, we study the HAWC sensitivity to the gamma-ray signatures of high-mass (multi- TeV) dark matter annihilation. The HAWC observatory will be sensitive to diverse searches for dark matter annihilation, including annihilation from extended dark matter sources, the diffuse gamma-ray emission from dark matter annihilation, and gamma-ray emission from non-luminous dark matter subhalos. Here we consider the HAWC sensitivity to a subset of these sources, including dwarf galaxies, the M31 galaxy, the Virgo cluster, and the Galactic center. We simulate the HAWC response to gamma rays from these sources in several well-motivated dark matter annihilation channels. If no gamma-ray excess is observed, we show the limits HAWC can place on the dark matter cross-section from these sources. In particular, in the case of dark matter annihilation into gauge bosons, HAWC will be able to detect a narrow range of dark matter masses to cross-sections below thermal. HAWC should also be sensitive to non-thermal cross-sections for masses up to nearly 1000 TeV. The constraints placed by HAWC on the dark matter cross-section from known sources should be competitive with current limits in the mass range where HAWC has similar sensitivity. HAWC can additionally explore higher dark matter masses than are currently constrained.Comment: 15 pages, 4 figures, version to be published in PR
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