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Sample records for endemic shrub arizona

  1. Vegetative propagation of the Azorean endemic shrub Viburnum treleasei Gand

    Directory of Open Access Journals (Sweden)

    MÓNICA MOURA

    2009-01-01

    Full Text Available Viburnum treleasei Gand. is a threatened hermaphroditic shrub or small tree endemic to the Azores islands. In this study we aimed at defining a fast, simple and cost-efficient propagation methodology that could be used by non-skilled workers in conservation actionplans. Our objective was also to produce cleaner material for initiation of in vitro cultures and to determine the effects of season, placement of cuttings in the branch, placement of vegetative buds in cuttings and forcing solutions in shoot development. It was possible to produce clean shoots from cuttings using a forcing solution with 8-hydroxyquinoline sulphate (8-HQS, 2% sucrose and no growth regulators addition. Shoot development results obtained with apical and sub-apical cuttings indicate that V. treleasei possessesapical dominance and deep endodormancy. Apical semihardwood cuttings in autumn or airlayered branches in autumn and winter with 2 or 5% (w/w of IBA produced excellent rooting results which will allow reinforcing depleted populations of V. treleasei efficientlyand at reduced costs.

  2. Endemic shrubs in temperate arid and semiarid regions of northern China and their potentials for rangeland restoration.

    Science.gov (United States)

    Chu, Jianmin; Yang, Hongxiao; Lu, Qi; Zhang, Xiaoyan

    2015-06-03

    Some endemic shrubs in arid and semiarid ecosystems are in danger of extinction, and yet they can play useful roles in maintaining or restoring these ecosystems, thus practical efforts are needed to conserve them. The shrubs Amygdalus pedunculata Pall., Amygdalus mongolica (Maxim.) Ricker and Ammopiptanthus mongolicus (Maxim. ex Kom.) Cheng f. are endemic species in arid and semiarid regions of northern China, where rangeland desertification is pronounced due to chronic overgrazing. In this study, we tested the hypothesis that these endemic shrubs have developed adaptations to arid and semiarid environments and could play critical roles as nurse species to initiate the process of rangeland recovery. Based on careful vegetation surveys, we analysed the niches of these species in relation to precipitation, temperature and habitats. All sampling plots were categorized by these endemics and sorted by the non-metric multidimensional scaling method. Species ratios of each life form and species co-occurrence rates with the endemics were also evaluated. Annual average temperature and annual precipitation were found to be the key factors determining vegetation diversity and distributions. Amygdalus pedunculata prefers low hills and sandy land in temperate semiarid regions. Amygdalus mongolica prefers gravel deserts of temperate semiarid regions. Ammopiptanthus mongolicus prefers sandy land of temperate arid regions. Communities of A. pedunculata have the highest diversity and the largest ratios of long-lived grass species, whereas those of A. mongolicus have the lowest diversity but the largest ratios of shrub species. Communities of A. mongolica are a transition between the first two community types. These findings demonstrate that our focal endemic shrubs have evolved adaptations to arid and semiarid conditions, thus they can be nurse plants to stabilize sand ground for vegetation restoration. We suggest that land managers begin using these shrub species to restore

  3. Plant population and habitat characteristics of the endemic Sonoran Desert cactus Peniocereus striatus in Organ Pipe Cactus National Monument, Arizona

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    Anderson, Greta; Rutman, Sue; Munson, Seth M.

    2010-01-01

    Peniocereus striatus (Brandegee) Buxb. (Cactaceae) is an endemic Sonoran Desert cactus that reaches its northern range limit in southwestern Arizona. One U.S. population occupies a small area of Organ Pipe Cactus National Monument near the U.S./Mexico international boundary, which has been monitored since 1939. An extensive survey conducted in 2002, covering 177 ha, resulted in the discovery of 88 new plants, in addition to the relocation of 57 plants found in previous surveys. Despite potential increases in population size and spatial distribution, mean plant height and number of basal stems has not significantly changed in recent years. Bud scars revealed that a majority of the population was sexually mature. Peniocereus striatus occurrence increased with decreasing slope, spanned every slope aspect, and was highest on rocky soils, but was noticeably low on west and northwest slopes and areas where severe land degradation had previously occurred. Over half of P. striatus plants were nursed by shrubs and subshrubs, while 40% occurred under leguminous trees. A severe frost in January 2002 top-killed 19% of the population, with the greatest damage in drainage bottoms. However, long-term (1944–2002) climate records show that there has been an overall increase in the number of frost free days in the region, which, coupled with land use change, has implications for the future health of this population.

  4. Nectar robbing in Collaea cipoensis (Fabaceae), an endemic shrub of the Brazilian rupestrian grasslands

    OpenAIRE

    Gelvez-Zúñiga, Irene; Aguirre, Armando; Martén-Rodríguez, Silvana; Matos-Gomes, Vanessa; Barbosa, Arleu; Bordignon, Leandra; Rocha, Rosana; Fernandes, Geraldo W.

    2016-01-01

    Abstract: Nectar robbery is common in flowering plants with tubular corollas and can affect plant reproductive success. Our study characterized the interaction between potential pollinators and nectar robbers, and assessed the effects on flower abortion in a population of the restricted endemic Collaea cipoensis (Fabaceae) at Serra do Cipó, Brazil. We conducted observations of floral visitors to identify potential pollinators from nectar robbers and described visitor behavior. We also analyze...

  5. Fire adaptation in Neblinaria celiae (Theaceae), a high-elevation rosette shrub endemic to a wet equatorial tepui

    Science.gov (United States)

    Givnish, T.J.; McDiarmid, R.W.; Buck, W.R.

    1986-01-01

    Neblinaria celiae (Theaceae), a rosette shrub endemic to the exceedingly rainy summit of remote Cerro de la Neblina in southern Venezuela, has a previously undescribed set of adaptations to fire. Its growth form entails sparse branching, massive terminal leaf rosettes, and thick bark. It is highly fire-tolerant, with a survival rate of 93% in a stand recently ignited by lightning, vs. 0% in seven co-occurring woody species. Survival increases sharply with rosette height, favoring a sparsely branched habit that would maximize the rate of upward growth through the sparse fuel layer supported by a sterile substrate. Thick bark and massive rosettes help protect cambial and foliar meristems from brief exposure to high temperatures. Rosettes on shorter plants are exposed to greater damage from fire near the ground and, as expected, are bigger and impound more rainwater; the greater number of leaves nearly balances the greater leaf mortality caused by fire. We relate Neblinaria's growth form to its dominance atop Neblina, to a general model for the evolution of sparse branching, and to the evolution of growth form in other tepui plants.

  6. Development and characterization of microsatellite markers for Tibouchina hatschbachii (Melastomataceae, an endemic and habitat-restricted shrub from Brazil

    Directory of Open Access Journals (Sweden)

    Fabiano Rodrigo Maia

    2016-12-01

    Full Text Available Tibouchina hatschbachii Wurdack (Melastomataceae is an autogamous shrub restricted to granite (GO and sandstone (SO rock outcrops from subtropical Brazil. We designed primers for the amplification of microsatellite regions for T. hatschbachii, and characterized these primers to estimate genetic diversity parameters and contemporary genetic structure patterns. Eight loci were successfully amplified and were characterized using 70 individuals from three natural populations. Polymorphic information content ranged from 0.200 to 0.772 per locus. All loci were polymorphic, with allele numbers ranging from two to eight. The low degree of polymorphism may be explained by the fact that T. hatschbachii has disjunct populations and a recent genetic bottleneck, and also that it is self-pollinated. The observed and expected heterozygosities ranged from 0.115 to 1.000 and from 0.112 to 0.800, respectively. We observed private alleles in all loci. These are important features that enable us to identify population differentiation and help to us understand gene flow patterns for T. hatschbachii in subtropical Brazil. Eight microsatellite loci from other species of Tibouchina amplified positively in T. hatschbachii.

  7. Penstemon lanceolatus Benth. or P. ramosus Crosswhite in Arizona and New Mexico, a peripheral or endemic species?

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    J. L. Anderson; S. Richmond-Williams; O. Williams

    2007-01-01

    The red-flowered member of Penstemon sect. Chamaeleon from southeastern Arizona and southwestern New Mexico has been treated taxonomically both as part of the Mexican species, P. lanceolatus Benth., and as a separate species, P. ramosus Crosswhite. Under the former treatment the Arizona and New Mexico populations are peripheral populations of a primarily Mexican...

  8. The relationship between climate change and the endangered rainforest shrub Triunia robusta (Proteaceae) endemic to southeast Queensland, Australia

    Science.gov (United States)

    Shimizu-Kimura, Yoko; Accad, Arnon; Shapcott, Alison

    2017-04-01

    Threatened species in rainforests may be vulnerable to climate change, because of their potentially narrow thermal tolerances, small population sizes and restricted distributions. This study modelled climate induced changes on the habitat distribution of the endangered rainforest plant Triunia robusta, endemic to southeast Queensland, Australia. Species distribution models were developed for eastern Australia at 250 m grids and southeast Queensland at 25 m grids using ground-truthed presence records and environmental predictor data. The species’ habitat distribution under the current climate was modelled, and the future potential habitat distributions were projected for the epochs 2030, 2050 and 2070. The eastern Australia model identified several spatially disjunct, broad habitat areas of coastal eastern Australia consistent with the current distribution of rainforests, and projected a southward and upslope contraction driven mainly by average temperatures exceeding current range limits. The southeast Queensland models suggest a dramatic upslope contraction toward locations where the majority of known populations are found. Populations located in the Sunshine Coast hinterland, consistent with past rainforest refugia, are likely to persist long-term. Upgrading the level of protection for less formal nature reserves containing viable populations is a high priority to better protect refugial T. robusta populations with respect to climate change.

  9. Rocky Mountain Spotted Fever Characterization and Comparison to Similar Illnesses in a Highly Endemic Area—Arizona, 2002–2011

    Science.gov (United States)

    Traeger, Marc S.; Regan, Joanna J.; Humpherys, Dwight; Mahoney, Dianna L.; Martinez, Michelle; Emerson, Ginny L.; Tack, Danielle M.; Geissler, Aimee; Yasmin, Seema; Lawson, Regina; Hamilton, Charlene; Williams, Velda; Levy, Craig; Komatsu, Kenneth; McQuiston, Jennifer H.; Yost, David A.

    2015-01-01

    Background Rocky Mountain spotted fever (RMSF) has emerged as a significant cause of morbidity and mortality since 2002 on tribal lands in Arizona. The explosive nature of this outbreak and the recognition of an unexpected tick vector, Rhipicephalus sanguineus, prompted an investigation to characterize RMSF in this unique setting and compare RMSF cases to similar illnesses. Methods We compared medical records of 205 patients with RMSF and 175 with non-RMSF illnesses that prompted RMSF testing during 2002–2011 from 2 Indian reservations in Arizona. Results RMSF cases in Arizona occurred year-round and peaked later (July–September) than RMSF cases reported from other US regions. Cases were younger (median age, 11 years) and reported fever and rash less frequently, compared to cases from other US regions. Fever was present in 81% of cases but not significantly different from that in patients with non-RMSF illnesses. Classic laboratory abnormalities such as low sodium and platelet counts had small and subtle differences between cases and patients with non-RMSF illnesses. Imaging studies reflected the variability and complexity of the illness but proved unhelpful in clarifying the early diagnosis. Conclusions RMSF epidemiology in this region appears different than RMSF elsewhere in the United States. No specific pattern of signs, symptoms, or laboratory findings occurred with enough frequency to consistently differentiate RMSF from other illnesses. Due to the nonspecific and variable nature of RMSF presentations, clinicians in this region should aggressively treat febrile illnesses and sepsis with doxycycline for suspected RMSF. PMID:25697743

  10. Pruning Shrubs

    OpenAIRE

    French, Sue (Sue C.); Appleton, Bonnie Lee, 1948-2012

    2009-01-01

    Understanding the "natural habit" or "shape" of shrubs will help you determine how to prune them. This publication explores how and when to prune, maintenance and rejuvenation pruning, and the growth habit of shrubs.

  11. Rocky mountain spotted fever characterization and comparison to similar illnesses in a highly endemic area-Arizona, 2002-2011.

    Science.gov (United States)

    Traeger, Marc S; Regan, Joanna J; Humpherys, Dwight; Mahoney, Dianna L; Martinez, Michelle; Emerson, Ginny L; Tack, Danielle M; Geissler, Aimee; Yasmin, Seema; Lawson, Regina; Hamilton, Charlene; Williams, Velda; Levy, Craig; Komatsu, Kenneth; McQuiston, Jennifer H; Yost, David A

    2015-06-01

    Rocky Mountain spotted fever (RMSF) has emerged as a significant cause of morbidity and mortality since 2002 on tribal lands in Arizona. The explosive nature of this outbreak and the recognition of an unexpected tick vector, Rhipicephalus sanguineus, prompted an investigation to characterize RMSF in this unique setting and compare RMSF cases to similar illnesses. We compared medical records of 205 patients with RMSF and 175 with non-RMSF illnesses that prompted RMSF testing during 2002-2011 from 2 Indian reservations in Arizona. RMSF cases in Arizona occurred year-round and peaked later (July-September) than RMSF cases reported from other US regions. Cases were younger (median age, 11 years) and reported fever and rash less frequently, compared to cases from other US regions. Fever was present in 81% of cases but not significantly different from that in patients with non-RMSF illnesses. Classic laboratory abnormalities such as low sodium and platelet counts had small and subtle differences between cases and patients with non-RMSF illnesses. Imaging studies reflected the variability and complexity of the illness but proved unhelpful in clarifying the early diagnosis. RMSF epidemiology in this region appears different than RMSF elsewhere in the United States. No specific pattern of signs, symptoms, or laboratory findings occurred with enough frequency to consistently differentiate RMSF from other illnesses. Due to the nonspecific and variable nature of RMSF presentations, clinicians in this region should aggressively treat febrile illnesses and sepsis with doxycycline for suspected RMSF. Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  12. Rocky Mountain spotted fever in Arizona: documentation of heavy environmental infestations of Rhipicephalus sanguineus at an endemic site.

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    Nicholson, William L; Paddock, Christopher D; Demma, Linda; Traeger, Marc; Johnson, Brian; Dickson, Jeffrey; McQuiston, Jennifer; Swerdlow, David

    2006-10-01

    A recent epidemiologic investigation identified 16 cases and 2 deaths from Rocky Mountain spotted fever (RMSF) in two eastern Arizona communities. Prevalence studies were conducted by collecting free-living ticks (Acari: Ixodidae) from the home sites of RMSF patients and from other home sites within the community. Dry ice traps and flagging confirmed heavy infestations at many of the home sites. Only Rhipicephalus sanguineus ticks were identified and all developmental stages were detected. It is evident that under certain circumstances, this species does transmit Rickettsia rickettsii to humans and deserves reconsideration as a vector in other geographic areas.

  13. Risk Factors for Fatal Outcome From Rocky Mountain Spotted Fever in a Highly Endemic Area—Arizona, 2002–2011

    Science.gov (United States)

    Regan, Joanna J.; Traeger, Marc S.; Humpherys, Dwight; Mahoney, Dianna L.; Martinez, Michelle; Emerson, Ginny L.; Tack, Danielle M.; Geissler, Aimee; Yasmin, Seema; Lawson, Regina; Williams, Velda; Hamilton, Charlene; Levy, Craig; Komatsu, Ken; Yost, David A.; McQuiston, Jennifer H.

    2016-01-01

    Background Rocky Mountain spotted fever (RMSF) is a disease that now causes significant morbidity and mortality on several American Indian reservations in Arizona. Although the disease is treatable, reported RMSF case fatality rates from this region are high (7%) compared to the rest of the nation (<1%), suggesting a need to identify clinical points for intervention. Methods The first 205 cases from this region were reviewed and fatal RMSF cases were compared to nonfatal cases to determine clinical risk factors for fatal outcome. Results Doxycycline was initiated significantly later in fatal cases (median, day 7) than nonfatal cases (median, day 3), although both groups of case patients presented for care early (median, day 2). Multiple factors increased the risk of doxycycline delay and fatal outcome, such as early symptoms of nausea and diarrhea, history of alcoholism or chronic lung disease, and abnormal laboratory results such as elevated liver aminotransferases. Rash, history of tick bite, thrombocytopenia, and hyponatremia were often absent at initial presentation. Conclusions Earlier treatment with doxycycline can decrease morbidity and mortality from RMSF in this region. Recognition of risk factors associated with doxycycline delay and fatal outcome, such as early gastrointestinal symptoms and a history of alcoholism or chronic lung disease, may be useful in guiding early treatment decisions. Healthcare providers should have a low threshold for initiating doxycycline whenever treating febrile or potentially septic patients from tribal lands in Arizona, even if an alternative diagnosis seems more likely and classic findings of RMSF are absent. PMID:25697742

  14. Risk factors for fatal outcome from rocky mountain spotted Fever in a highly endemic area-Arizona, 2002-2011.

    Science.gov (United States)

    Regan, Joanna J; Traeger, Marc S; Humpherys, Dwight; Mahoney, Dianna L; Martinez, Michelle; Emerson, Ginny L; Tack, Danielle M; Geissler, Aimee; Yasmin, Seema; Lawson, Regina; Williams, Velda; Hamilton, Charlene; Levy, Craig; Komatsu, Ken; Yost, David A; McQuiston, Jennifer H

    2015-06-01

    Rocky Mountain spotted fever (RMSF) is a disease that now causes significant morbidity and mortality on several American Indian reservations in Arizona. Although the disease is treatable, reported RMSF case fatality rates from this region are high (7%) compared to the rest of the nation (<1%), suggesting a need to identify clinical points for intervention. The first 205 cases from this region were reviewed and fatal RMSF cases were compared to nonfatal cases to determine clinical risk factors for fatal outcome. Doxycycline was initiated significantly later in fatal cases (median, day 7) than nonfatal cases (median, day 3), although both groups of case patients presented for care early (median, day 2). Multiple factors increased the risk of doxycycline delay and fatal outcome, such as early symptoms of nausea and diarrhea, history of alcoholism or chronic lung disease, and abnormal laboratory results such as elevated liver aminotransferases. Rash, history of tick bite, thrombocytopenia, and hyponatremia were often absent at initial presentation. Earlier treatment with doxycycline can decrease morbidity and mortality from RMSF in this region. Recognition of risk factors associated with doxycycline delay and fatal outcome, such as early gastrointestinal symptoms and a history of alcoholism or chronic lung disease, may be useful in guiding early treatment decisions. Healthcare providers should have a low threshold for initiating doxycycline whenever treating febrile or potentially septic patients from tribal lands in Arizona, even if an alternative diagnosis seems more likely and classic findings of RMSF are absent. Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  15. Chapter 22. Rosaceous shrubs

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    Nancy L. Shaw; Stephen B. Monsen; Richard Stevens

    2004-01-01

    Important shrubs of the Rose Family (Rosaceae) in the Intermountain region are distributed from blackbrush and salt desert shrub communities through high elevation forests and meadows. Growth habits of this group vary from trailing brambles to upright shrubs and small trees. Some species are evergreen while others are deciduous. Many of these species are highly valued...

  16. Home gardening near a mining site in an arsenic-endemic region of Arizona: assessing arsenic exposure dose and risk via ingestion of home garden vegetables, soils, and water.

    Science.gov (United States)

    Ramirez-Andreotta, Monica D; Brusseau, Mark L; Beamer, Paloma; Maier, Raina M

    2013-06-01

    The human-health risk posed by gardening near a legacy mine and smelter in an arsenic-endemic region of Arizona was characterized in this study. Residential soils were used in a greenhouse study to grow common vegetables, and local residents, after training, collected soil, water, and vegetables samples from their home gardens. Concentrations of arsenic measured in water, soil, and vegetable samples were used in conjunction with reported US intake rates to calculate the daily dose, Incremental Excess Lifetime Cancer Risk (IELCR), and Hazard Quotient for arsenic. Relative arsenic intake dose decreased in order: water>garden soils>homegrown vegetables, and on average, each accounted for 77, 16, and 7% of a residential gardener's daily arsenic intake dose. The IELCR ranges for vegetables, garden soils, and water were 10(-8) to 10(-4), 10(-6) to 10(-4), and 10(-5) to 10(-2), respectively. All vegetables (greenhouse and home garden) were grouped by scientific family, and the risk posed decreased as: Asteraceae≫Fabaceae>Amaranthaceae>Liliaceae>Brassicaceae>Solanaceae≫Cucurbitaceae. Correlations observed between concentrations of arsenic in vegetables and soils were used to estimate a maximum allowable level of arsenic in soil to limit the excess cancer risk to 10(-6). The estimated values are 1.56 mg kg(-1), 5.39 mg kg(-1), 11.6 mg kg(-1) and 12.4 mg kg(-1) for the Asteraceae, Brassicaceae, Fabaceae, and Amaranthaceae families, respectively. It is recommended that home gardeners: sample their private wells annually, test their soils prior to gardening, and, if necessary, modify their gardening behavior to reduce incidental soil ingestion. This study highlights the importance of site-specific risk assessment, and the need for species-specific planting guidelines for communities. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Arizona transportation history.

    Science.gov (United States)

    2011-12-01

    The Arizona transportation history project was conceived in anticipation of Arizonas centennial, which will be : celebrated in 2012. Following approval of the Arizona Centennial Plan in 2007, the Arizona Department of : Transportation (ADOT) recog...

  18. Micropropagation of the endangered shrub pondberry (Lindera melissifolia [Walt.] Blume)

    Science.gov (United States)

    Tracy S. Hawkins; Nathan M. Schiff; Emile s. Gardiner; Theodore Leininger; Margaret S. Devall; A. Dan Wilson; Paul Hamel; Deborah D. McCown; Kristina Connor

    2007-01-01

    A micropropagation protocol using shoot cultures is described for Lindera melissifolia, a federally listed endangered shrub endemic to the southeastern United States. Stock plants were harvested from native L. melissifolia populations growing in the lower Mississippi Alluvial Valley. In vitro proliferation was on woody plant medium...

  19. Changes in Nitrogen Cycling in a Shrub-Encroached Dryland

    Science.gov (United States)

    Turpin-Jelfs, T. C.; Michaelides, K.; Biederman, J. A.; Evershed, R. P.; Anesio, A. M.

    2017-12-01

    Land degradation is estimated to have occurred in 10-20% of Earth's drylands, where the environmental and socioeconomic consequences have affected 250 million people. The prevailing form of land degradation in drylands over the past ca. 150 years has been the encroachment of woody plants into arid and semi-arid grasslands. The density of mesquite (Prosopis spp.), a significant nitrogen (N)-fixing woody encroacher, has increased within the arid and semi-arid grasslands of the southwestern US by >400% over the past 30 years to occupy an area of >38 Mha. However, the impacts of an increasing density of N-fixing shrubs on the cycling and spatial variability of N within these ecosystems remains poorly understood. Here, we quantify how concentrations of N (ammonium-N, nitrate-N, organic N), as well as carbon (C; total C and organic C) and phosphorous (P; loosely-bound P, iron- and aluminium-bound P, apatite P and calcite-bound P, and residual P), and the structure of the microbial community (phospholipid fatty acids), change in the soils underneath and between shrub canopies along a gradient of shrub-encroachment for a semiarid grassland in the Santa Rita Experimental Range (SRER) Arizona, US. This gradient of encroachment was comprised of five sites that ranged from a grass dominated state to a shrub-dominated state characterised by mosaics of shrub patches and bare-soil interspaces. Our results show that the organic C and total N content of soils between shrubs decreased by >50% between grass dominant and shrub dominant end-member sites. Conversely, the organic C and total N content of soils beneath shrub canopies remained relatively constant along the encroachment gradient.

  20. Measuring carbon in shrubs. Chapter 5

    Science.gov (United States)

    David C. Chojnacky; Mikaila Milton

    2008-01-01

    Although shrubs are a small component of the overall carbon budget, shrub lands and shrub cover within forested lands warrant monitoring with consistent procedures to account for carbon in shrubs and to track carbon accumulation as communities change from shrubs to trees and vice versa. Many different procedures have been used to sample and measure shrubs (Bonham 1989...

  1. Ecoregions of Arizona (poster)

    Science.gov (United States)

    Griffith, Glenn E.; Omernik, James M.; Johnson, Colleen Burch; Turner, Dale S.

    2014-01-01

    Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources; they are designed to serve as a spatial framework for the research, assessment, management, and monitoring of ecosystems and ecosystem components. By recognizing the spatial differences in the capacities and potentials of ecosystems, ecoregions stratify the environment by its probable response to disturbance. These general purpose regions are critical for structuring and implementing ecosystem management strategies across federal agencies, state agencies, and nongovernment organizations that are responsible for different types of resources within the same geographical areas. The Arizona ecoregion map was compiled at a scale of 1:250,000. It revises and subdivides an earlier national ecoregion map that was originally compiled at a smaller scale. The approach used to compile this map is based on the premise that ecological regions can be identified through the analysis of the spatial patterns and the composition of biotic and abiotic phenomena that affect or reflect differences in ecosystem quality and integrity. These phenomena include geology, physiography, vegetation, climate, soils, land use, wildlife, and hydrology. The relative importance of each characteristic varies from one ecological region to another regardless of the hierarchical level. A Roman numeral hierarchical scheme has been adopted for different levels of ecological regions. Level I is the coarsest level, dividing North America into 15 ecological regions. Level II divides the continent into 50 regions. At level III, the continental United States contains 105 ecoregions and the conterminous United States has 85 ecoregions. Level IV is a further subdivision of level III ecoregions. Arizona contains arid deserts and canyonlands, semiarid shrub- and grass-covered plains, woodland- and shrubland-covered hills, lava fields and volcanic plateaus, forested mountains, glaciated

  2. Mapping the ecological dimensions and potential distributions of endangered relic shrubs in western Ordos biodiversity center.

    Science.gov (United States)

    Zhu, Geng-Ping; Li, Hui-Qi; Zhao, Li; Man, Liang; Liu, Qiang

    2016-05-20

    Potential distributions of endemic relic shrubs in western Ordos were poorly mapped, which hindered our implementation of proper conservation. Here we investigated the applicability of ecological niche modeling for endangered relic shrubs to detect areas of priority for biodiversity conservation and analyze differences in ecological niche spaces used by relic shrubs. We applied ordination and niche modeling techniques to assess main environmental drivers of five endemic relic shrubs in western Ordos, namely, Ammopiptanthus mongolicus, Amygdalus mongolica, Helianthemum songaricum, Potaninia mongolica, and Tetraena mongolica. We calculated niche overlap metrics in gridded environmental spaces and compared geographical projections of ecological niches to determine similarities and differences of niches occupied by relic shrubs. All studied taxa presented different responses to environmental factors, which resulted in a unique combination of niche conditions. Precipitation availability and soil quality characteristics play important roles in the distributions of most shrubs. Each relic shrub is constrained by a unique set of environmental conditions, the distribution of one species cannot be implied by the distribution of another, highlighting the inadequacy of one-fits-all type of conservation measure. Our stacked habitat suitability maps revealed regions around Yellow River, which are highly suitable for most species, thereby providing high conservation value.

  3. Shrub expansion in SW Greenland

    DEFF Research Database (Denmark)

    Jørgensen, Rasmus Halfdan

    Arctic regions have experienced higher temperatures in recent decades, and the warming trend is projected to continue in the coming years. Arctic ecosystems are considered to be particularly vulnerable to climate change. Expansion of shrubs has been observed widely in tundra areas across the Arctic......, and has a range of ecosystem effects where it occurs. Shrub expansion has to a large extend been attributed to increasing temperatures over the past century, while grazing and human disturbance have received less attention. Alnus viridis ssp. crispa is a common arctic species that contributes...... to increasing shrub cover. Despite this, there is only limited experimental evidence that growth of the species responds to warming. Plant populations in fragmented and isolated locations could face problems adapting to a warming climate due to limited genetic variation and restricted migration from southern...

  4. Root systems of chaparral shrubs.

    Science.gov (United States)

    Kummerow, Jochen; Krause, David; Jow, William

    1977-06-01

    Root systems of chaparral shrubs were excavated from a 70 m 2 plot of a mixed chaparral stand located on a north-facing slope in San Diego County (32°54' N; 900 m above sea level). The main shrub species present were Adenostoma fasciculatum, Arctostaphylos pungens, Ceanothus greggii, Erigonum fasciculatum, and Haplopappus pinifolius. Shrubs were wired into their positions, and the soil was washed out beneath them down to a depth of approximately 60 cm, where impenetrable granite impeded further washing and root growth was severely restricted. Spacing and interweaving of root systems were recorded by an in-scale drawing. The roots were harvested in accordance to their depths, separated into diameter size classes for each species, and their dry weights measured. Roots of shrubs were largely confined to the upper soil levels. The roots of Eriogonum fasciculatum were concentrated in the upper soil layer. Roots of Adenostoma fasciculatum tended to be more superficial than those from Ceanothus greggii. It is hypothesized that the shallow soil at the excavation site impeded a clear depth zonation of the different root systems. The average dry weight root:shoot ratio was 0.6, ranging for the individual shrubs from 0.8 to 0.4. The root area always exceeded the shoot area, with the corresponding ratios ranging from 6 for Arctostaphylos pungens to 40 for Haplopappus pinifolius. The fine root density of 64 g dry weight per m 2 under the canopy was significantly higher than in the unshaded area. However, the corresponding value of 45 g dry weight per m 2 for the open ground is still high enough to make the establishment of other shrubs difficult.

  5. Chapter 23. Shrubs of other families

    Science.gov (United States)

    Stephen B. Monsen; Richard Stevens; Nancy L. Shaw

    2004-01-01

    Numerous genera and species of shrubs occur throughout the Intermountain region in addition to those included in the Asteraceae, Chenopodiaceae, and Rosaceae families. Although shrubs are widespread throughout this region and dominate many areas, species richness is low compared to the shrub flora of the Pacific United States, Chile, western Australia, and South Africa...

  6. Legume Shrubs Are More Nitrogen-Homeostatic than Non-legume Shrubs.

    Science.gov (United States)

    Guo, Yanpei; Yang, Xian; Schöb, Christian; Jiang, Youxu; Tang, Zhiyao

    2017-01-01

    Legumes are characterized as keeping stable nutrient supply under nutrient-limited conditions. However, few studies examined the legumes' stoichiometric advantages over other plants across various taxa in natural ecosystems. We explored differences in nitrogen (N) and phosphorus (P) stoichiometry of different tissue types (leaf, stem, and root) between N 2 -fixing legume shrubs and non-N 2 -fixing shrubs from 299 broadleaved deciduous shrubland sites in northern China. After excluding effects of taxonomy and environmental variables, these two functional groups differed considerably in nutrient regulation. N concentrations and N:P ratios were higher in legume shrubs than in non-N 2 -fixing shrubs. N concentrations were positively correlated between the plants and soil for non-N 2 -fixing shrubs, but not for legume shrubs, indicating a stronger stoichiometric homeostasis in legume shrubs than in non-N 2 -fixing shrubs. N concentrations were positively correlated among three tissue types for non-N 2 -fixing shrubs, but not between leaves and non-leaf tissues for legume shrubs, demonstrating that N concentrations were more dependent among tissues for non-N 2 -fixing shrubs than for legume shrubs. N and P concentrations were correlated within all tissues for both functional groups, but the regression slopes were flatter for legume shrubs than non-N 2 -fixing shrubs, implying that legume shrubs were more P limited than non-N 2 -fixing shrubs. These results address significant differences in stoichiometry between legume shrubs and non-N 2 -fixing shrubs, and indicate the influence of symbiotic nitrogen fixation (SNF) on plant stoichiometry. Overall, N 2 -fixing legume shrubs are higher and more stoichiometrically homeostatic in N concentrations. However, due to excess uptake of N, legumes may suffer from potential P limitation. With their N advantage, legume shrubs could be good nurse plants in restoration sites with degraded soil, but their P supply should be taken care

  7. Chemicals from trees and shrubs

    Energy Technology Data Exchange (ETDEWEB)

    Halloran, G M

    1978-01-01

    The need for finding economically viable alternatives to crude oil is discussed in the context of Australia's uncertain reserves of black coal, from which crude oil derivatives may have to be obtained when oil supplies become depleted. A table is presented showing the major fractions of crude oil and the likely sources (in general terms) of equivalent substances from forest trees, shrubs and agricultural species.

  8. The Virtual Arizona Experience

    Science.gov (United States)

    Allison, M. L.; Davis, R.; Conway, F. M.; Bellasai, R.

    2012-12-01

    To commemorate the once-in-a-lifetime event of Arizona's hundredth birthday, the Centennial Commission and the Governor of Arizona envisioned a museum and companion website that would capture the state's history, celebrate its people, and embrace its future. Working with world-renowned museum designers, the state began to seek ideas from across Arizona to create plans for a journey of discovery through science and the humanities. The museum would introduce visitors to some of the people who nurtured the state through its early years and others who are innovating its tomorrows. Showcases would include the resources and experiences that shaped the state's history and are transforming its present day, highlighting the ingenuity that tamed the wild frontier and is envisioning Arizona's next frontiers through science and technology. The Arizona Experience (www.arizonaexperience.org) was initially intended to serve as the web presence for the physical museum, but as delays occurred with the physical museum, the site has quickly developed an identify of its own as an interactive, multimedia experience, reaching a wider audience with functions that would be difficult or expensive to produce in a museum. As leaders in scientific and technological innovation in the state, the Arizona Geological Survey was tasked with designing and creating the Arizona Experience site. The general themes remain the same; however, the site has added content and applications that are better suited to the online environment in order to create a rich, dynamic supplement to a physical museum experience. The website offers the features and displays of the future museum with the interactive nature and learning environment of the web. This provides an encyclopedic overview of the State of Arizona by subject matter experts in a manner that is free and open to the public and erases socio-economic, political, and physical boundaries. Over the Centennial Year of 2012 the site will release a new theme and

  9. Stem secondary growth of tundra shrubs

    DEFF Research Database (Denmark)

    Campioli, Matteo; Leblans, Niki; Michelsen, Anders

    2012-01-01

    Our knowledge of stem secondary growth of arctic shrubs (a key component of tundra net primary production, NPP) is very limited. Here, we investigated the impact of the physical elements of the environment on shrub secondary growth by comparing annual growth rates of model species from similar...... growth (stem apical growth, stem length, and apical growth of stem plus leaves), in some cases even with opposite responses. Thus caution should be taken when estimating the impact of the environment on shrub growth from apical growth only. Integration of our data set with the (very limited) previously...

  10. Kaljujooniste keskus Arizonas / Andres Kurg

    Index Scriptorium Estoniae

    Kurg, Andres, 1975-

    1998-01-01

    Arhitekt William Bruderi projekteeritud kaljujooniste uurimis- ja eksponeerimiskeskus Phoenixis, Arizonas säilitab kivijooniseid, mille autoriteks olid sealset piirkonda kuni 16. sajandini asustanud hohokamid

  11. Detection of Mycoplasma gallisepticum in House Finches ( Haemorhous mexicanus) from Arizona.

    Science.gov (United States)

    Staley, Molly; Bonneaud, Camille; McGraw, Kevin J; Vleck, Carol M; Hill, Geoffrey E

    2018-03-01

    In 1994, an endemic poultry pathogen, Mycoplasma gallisepticum (MG), was identified as the causative agent of a novel disease in house finches ( Haemorhous mexicanus). After an initial outbreak in Maryland, MG spread rapidly throughout eastern North American populations of house finches. Subsequently, MG spread slowly through the northern interior of North America and then into the Pacific Northwest, finally reaching California in 2006. Until 2009, there were no reports of MG in the southwestern United States east of California. In August 2011, after reports of house finches displaying conjunctivitis characteristic of MG infection in Arizona, we trapped house finches at bird feeders in central Arizona (Tempe) and southern Arizona (Tucson and Green Valley) to assay for MG infection. Upon capture, we noted whether birds exhibited conjunctivitis, and we collected choanal swabs to test for the presence of MG DNA using PCR. We detected MG in finches captured from Green Valley (in ∼12% of birds captured), but not in finches from Tucson or Tempe. Based on resampling of house finches at these sites in July 2014, we suggest that central Arizona finches likely remain unexposed to MG. We also suggest that low urban connectivity between arid habitats of southern and central Arizona or a reduction in the prevalence of MG after its initial arrival in Arizona may be limiting the spread of MG from south to north in Arizona. In addition, the observed conjunctivitis-like signs in house finches that were negative for MG by PCR may be caused primarily by avian pox virus.

  12. Arizona Conserve Water Educators Guide

    Science.gov (United States)

    Project WET Foundation, 2007

    2007-01-01

    This award-winning, 350-page, full-color book provides a thorough study of Arizona water resources from a water conservation perspective. Its background section contains maps, graphs, diagrams and photos that facilitate the teaching of 15 interactive, multi-disciplinary lessons to K-12 students. In addition, 10 Arizona case studies are highlighted…

  13. Elevational plant species richness patterns and their drivers across non-endemics, endemics and growth forms in the Eastern Himalaya.

    Science.gov (United States)

    Manish, Kumar; Pandit, Maharaj K; Telwala, Yasmeen; Nautiyal, Dinesh C; Koh, Lian Pin; Tiwari, Sudha

    2017-09-01

    Despite decades of research, ecologists continue to debate how spatial patterns of species richness arise across elevational gradients on the Earth. The equivocal results of these studies could emanate from variations in study design, sampling effort and data analysis. In this study, we demonstrate that the richness patterns of 2,781 (2,197 non-endemic and 584 endemic) angiosperm species along an elevational gradient of 300-5,300 m in the Eastern Himalaya are hump-shaped, spatial scale of extent (the proportion of elevational gradient studied) dependent and growth form specific. Endemics peaked at higher elevations than non-endemics across all growth forms (trees, shrubs, climbers, and herbs). Richness patterns were influenced by the proportional representation of the largest physiognomic group (herbs). We show that with increasing spatial scale of extent, the richness patterns change from a monotonic to a hump-shaped pattern and richness maxima shift toward higher elevations across all growth forms. Our investigations revealed that the combination of ambient energy (air temperature, solar radiation, and potential evapo-transpiration) and water availability (soil water content and precipitation) were the main drivers of elevational plant species richness patterns in the Himalaya. This study highlights the importance of factoring in endemism, growth forms, and spatial scale when investigating elevational gradients of plant species distributions and advances our understanding of how macroecological patterns arise.

  14. Ecosystem response to removal of exotic riparian shrubs and a transition to upland vegetation

    Science.gov (United States)

    Reynolds, Lindsay V.; Cooper, David J.

    2011-01-01

    Understanding plant community change over time is essential for managing important ecosystems such as riparian areas. This study analyzed historic vegetation using soil seed banks and the effects of riparian shrub removal treatments and channel incision on ecosystem and plant community dynamics in Canyon de Chelly National Monument, Arizona. We focused on how seeds, nutrients, and ground water influence the floristic composition of post-treatment vegetation and addressed three questions: (1) How does pre-treatment soil seed bank composition reflect post-treatment vegetation composition? (2) How does shrub removal affect post-treatment riparian vegetation composition, seed rain inputs, and ground water dynamics? and (3) Is available soil nitrogen increased near dead Russian olive plants following removal and does this influence post-treatment vegetation? We analyzed seed bank composition across the study area, analyzed differences in vegetation, ground water levels, and seed rain between control, cut-stump and whole-plant removal areas, and compared soil nitrogen and vegetation near removed Russian olive to areas lacking Russian olive. The soil seed bank contained more riparian plants, more native and fewer exotic plants than the extant vegetation. Both shrub removal methods decreased exotic plant cover, decreased tamarisk and Russian olive seed inputs, and increased native plant cover after 2 years. Neither method increased ground water levels. Soil near dead Russian olive trees indicated a short-term increase in soil nitrogen following plant removal but did not influence vegetation composition compared to areas without Russian olive. Following tamarisk and Russian olive removal, our study sites were colonized by upland plant species. Many western North American rivers have tamarisk and Russian olive on floodplains abandoned by channel incision, river regulation or both. Our results are widely applicable to sites where drying has occurred and vegetation

  15. Divergent evapotranspiration partition dynamics between shrubs and grasses in a shrub-encroached steppe ecosystem.

    Science.gov (United States)

    Wang, Pei; Li, Xiao-Yan; Wang, Lixin; Wu, Xiuchen; Hu, Xia; Fan, Ying; Tong, Yaqin

    2018-06-04

    Previous evapotranspiration (ET) partitioning studies have usually neglected competitions and interactions between antagonistic plant functional types. This study investigated whether shrubs and grasses have divergent ET partition dynamics impacted by different water-use patterns, canopy structures, and physiological properties in a shrub-encroached steppe ecosystem in Inner Mongolia, China. The soil water-use patterns of shrubs and grasses have been quantified by an isotopic tracing approach and coupled into an improved multisource energy balance model to partition ET fluxes into soil evaporation, grass transpiration, and shrub transpiration. The mean fractional contributions to total ET were 24 ± 13%, 20 ± 4%, and 56 ± 16% for shrub transpiration, grass transpiration, and soil evaporation respectively during the growing season. Difference in ecohydrological connectivity and leaf development both contributed to divergent transpiration partitioning between shrubs and grasses. Shrub-encroachment processes result in larger changes in the ET components than in total ET flux, which could be well explained by changes in canopy resistance, an ecosystem function dominated by the interaction of soil water-use patterns and ecosystem structure. The analyses presented here highlight the crucial effects of vegetation structural changes on the processes of land-atmosphere interaction and climate feedback. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

  16. Shrubs and vines for northeastern wildlife

    Science.gov (United States)

    John D. Gill; William M. Healy

    1974-01-01

    A non-technical handbook in which 34 authors discuss management of 97 native and 3 naturalized shrubs or woody vines most important to wildlife in the Northeast,-Kentucky to Maryland to Newfoundland to Ontario. Topics include range, habitat, life history, uses, propagation, and management; but not identification.

  17. Legume Shrubs Are More Nitrogen-Homeostatic than Non-legume Shrubs

    OpenAIRE

    Guo, Yanpei; Yang, Xian; Schöb, Christian; Jiang, Youxu; Tang, Zhiyao

    2017-01-01

    Legumes are characterized as keeping stable nutrient supply under nutrient-limited conditions. However, few studies examined the legumes' stoichiometric advantages over other plants across various taxa in natural ecosystems. We explored differences in nitrogen (N) and phosphorus (P) stoichiometry of different tissue types (leaf, stem, and root) between N2-fixing legume shrubs and non-N2-fixing shrubs from 299 broadleaved deciduous shrubland sites in northern China. After excluding effects of ...

  18. Shrub water use dynamics in arctic Alaska

    Science.gov (United States)

    Clark, J.; Young-Robertson, J. M.; Tape, K. D.

    2016-12-01

    In the Arctic tundra, hydrologic processes influence the majority of ecosystem processes, from soil thermal dynamics to energy balance and trace gas exchange to vegetation community distributions. The tundra biome is experiencing a broad spectrum of ecosystem changes spurred by 20th century warming, including deciduous shrub expansion. Deciduous woody vegetation typically has high water use rates compared to evergreen and herbaceous species, and is projected to have a greater impact on energy balance than altered albedo from changes in snowpack. However, the impact of greater shrub cover on water balance has been overlooked. Shrubs have the potential to significantly dry the soil, accessing stored soil moisture in the organic layers, while increasing atmospheric moisture. The goal of this study is to quantify the water use dynamics (sap flux and stem water content) of three common arctic shrub species (Salix alexensis, S. pulchra, Betula nana) over two growing seasons. Stem water content was measured through a novel application of time domain reflectometry (TDR). Maximum sap flow rates varied by species: S. alexensis-600g/hr, S. pulchra-60g/hr, and B. nana-40g/hr. We found daily sap flow rates are highly correlated with atmospheric moisture demand (VPD) and not limited by soil moisture or antecedent precipitation. Stem water content varied between 20% and 60%, was correlated with soil moisture, and showed weak diurnal variation. This is one of the first studies to provide a detailed look at arctic tundra shrub water balance and explore the environmental controls on water flux. Planned future work will expand on these results for estimates of evapotranspiration over larger landscape areas.

  19. Effects of sub-Arctic shrub canopies on snowmelt energetics

    Science.gov (United States)

    Bewley, D.; Essery, R.; Pomeroy, J.

    2006-12-01

    Much of the low Arctic is covered with shrub tundra, and there is increasing evidence that snowmelt rates are substantially different between shrub tundra and poorly vegetated sites. The cause of this remains uncertain, however, and extends beyond simple differences in albedo. Results are presented in this study from a detailed field investigation at Wolf Creek Research Basin in 2004 to determine the effect of two different shrub canopy structures on both melt rates and the partitioning of melt energy. The low shrub site (LSS) was essentially an unvegetated snowfield prior to melt (mean albedo ~0.85), and shrubs only became exposed during the last few days of melt reaching a mean height of 0.31 m and mean Plant Area Index (PAI) of 0.32. Shrubs at the tall shrub site (TSS) were partially buried initially (shrub fraction, mean height and PAI of 0.2, 0.9 m and 0.41) but dominated the landscape by the end of melt (corresponding values of 0.71, 1.6 m and 0.6). Melt rates were higher at TSS up until the exposure of shrubs and bare ground at LSS, after which the rates converged. A Shrub-Snow Canopy Model (SSCM) is developed to improve snowmelt simulations for shrub canopies by parameterizing the key shrub effects on surface fluxes, including the extinction of shortwave irradiance beneath shrubs and in canopy gaps, and the enhancement of snow surface fluxes of longwave radiation and sensible heat. SSCM was run for LSS assuming no shrubs were present above the variable snow and bare ground tiles, whereas for TSS an increasing shrub fraction above each tile was prescribed from observations. Results from both sites suggest that sensible heat fluxes contributed more melt energy than net radiation, and were greater during early melt at TSS due to the warming of exposed shrubs. SWE was accurately predicted against transect measurements at TSS (rms error 4 mm), but was overestimated at LSS (rms error 13 mm) since both air temperatures and turbulent transport were underestimated

  20. Density and elevational distribution of the San Francisco Peaks ragwort, Packera franciscana (Asteraceae), a threatened single-mountain endemic

    Science.gov (United States)

    James F. Fowler; Carolyn Hull Sieg

    2011-01-01

    Packera franciscana (Greene) W. A. Weber and A. Love is endemic to treeline and alpine habitats of the San Francisco Peaks, Arizona, USA and was listed as a threatened species under the Endangered Species Act in 1983. Species abundance data are limited in scope, yet are critical for recovery of the species, especially in light of predictions of its future extinction...

  1. Estimating shrub biomass from basal stem diameters

    Energy Technology Data Exchange (ETDEWEB)

    Brown, J K

    1976-01-01

    Stem lengths and oven dry wt of stemwood and foilage were determined for shrubs in dia classes of 0 to 0.5 cm, 0.5 to 2 cm and 2 to 5 cm in various habitat types in Idaho and Montana. The logarithm of basal stem dia was closely correlated with the logarithm of wt. Regression components are presented for estimating leaf wt and total above-ground wt of 25 woody shrub species using a linear equation relating these 2 variables. Percentage stemwood wt is given for the 3 dia classes. Dia distributions for the smallest dia class were normal except for a few species with fine twigs; distributions for the other classes were positively skewed. Applications to forest fuel studies are briefly discussed.

  2. Estimating shrub biomass from basal stem diameters

    Energy Technology Data Exchange (ETDEWEB)

    Brown, J K

    1976-01-01

    Stem lengths and oven dry wt of stemwood and foilage were determined for shrubs in dia classes of 0 to 0.5 cm, 0.5 to 2 cm and 2 to 5 cm in various habitat types in Idaho and Montana. The logarithm of basal stem dia was closely correlated with the logarithm of wt. Regression components are presented for estimating leaf wt and total above-ground wt of 25 woody shrub species using a linear equation relating these 2 variables. Percentage stemwood wt is given for the 3 dia classes. Dia distributions for the smallest dia class were normal except for a few species with fine twigs: distributions for the other classes were positively skewed. Applications to forest fuel studies are briefly discussed.

  3. Contrasting shrub species respond to early summer temperatures leading to correspondence of shrub growth patterns

    Science.gov (United States)

    Weijers, Stef; Pape, Roland; Löffler, Jörg; Myers-Smith, Isla H.

    2018-03-01

    The Arctic-alpine biome is warming rapidly, resulting in a gradual replacement of low statured species by taller woody species in many tundra ecosystems. In northwest North America, the remotely sensed normalized difference vegetation index (NDVI), suggests an increase in productivity of the Arctic and alpine tundra and a decrease in productivity of boreal forests. However, the responses of contrasting shrub species growing at the same sites to climate drivers remain largely unexplored. Here, we test growth, climate, and NDVI relationships of two contrasting species: the expanding tall deciduous shrub Salix pulchra and the circumarctic evergreen dwarf shrub Cassiope tetragona from an alpine tundra site in the Pika valley in the Kluane Region, southwest Yukon Territories, Canada. We found that annual growth variability of both species at this site is strongly driven by early summer temperatures, despite their contrasting traits and habitats. Shrub growth chronologies for both species were correlated with the regional climate signal and showed spatial correspondence with interannual variation in NDVI in surrounding alpine and Arctic regions. Our results suggest that early summer warming represents a common driver of vegetation change for contrasting shrub species growing in different habitats in the same alpine environments.

  4. Expansion of deciduous tall shrubs but not evergreen dwarf shrubs inhibited by reindeer in Scandes mountain range.

    Science.gov (United States)

    Vowles, Tage; Gunnarsson, Bengt; Molau, Ulf; Hickler, Thomas; Klemedtsson, Leif; Björk, Robert G

    2017-11-01

    One of the most palpable effects of warming in Arctic ecosystems is shrub expansion above the tree line. However, previous studies have found that reindeer can influence plant community responses to warming and inhibit shrubification of the tundra.We revisited grazed (ambient) and ungrazed study plots (exclosures), at the southern as well as the northern limits of the Swedish alpine region, to study long-term grazing effects and vegetation changes in response to increasing temperatures between 1995 and 2011, in two vegetation types (shrub heath and mountain birch forest).In the field layer at the shrub heath sites, evergreen dwarf shrubs had increased in cover from 26% to 49% but were unaffected by grazing. Deciduous dwarf and tall shrubs also showed significant, though smaller, increases over time. At the birch forest sites, the increase was similar for evergreen dwarf shrubs (20-48%) but deciduous tall shrubs did not show the same consistent increase over time as in the shrub heath.The cover and height of the shrub layer were significantly greater in exclosures at the shrub heath sites, but no significant treatment effects were found on species richness or diversity.July soil temperatures and growing season thawing degree days (TDD) were higher in exclosures at all but one site, and there was a significant negative correlation between mean shrub layer height and soil TDD at the shrub heath sites. Synthesis . This study shows that shrub expansion is occurring rapidly in the Scandes mountain range, both above and below the tree line. Tall, deciduous shrubs had benefitted significantly from grazing exclosure, both in terms of cover and height, which in turn lowered summer soil temperatures. However, the overriding vegetation shift across our sites was the striking increase in evergreen dwarf shrubs, which were not influenced by grazing. As the effects of an increase in evergreen dwarf shrubs and more recalcitrant plant litter may to some degree counteract some of

  5. Rickettsia parkeri Rickettsiosis, Arizona, USA.

    Science.gov (United States)

    Herrick, Kristen L; Pena, Sandra A; Yaglom, Hayley D; Layton, Brent J; Moors, Amanda; Loftis, Amanda D; Condit, Marah E; Singleton, Joseph; Kato, Cecilia Y; Denison, Amy M; Ng, Dianna; Mertins, James W; Paddock, Christopher D

    2016-05-01

    In the United States, all previously reported cases of Rickettsia parkeri rickettsiosis have been linked to transmission by the Gulf Coast tick (Amblyomma maculatum). Here we describe 1 confirmed and 1 probable case of R. parkeri rickettsiosis acquired in a mountainous region of southern Arizona, well beyond the recognized geographic range of A. maculatum ticks. The likely vector for these 2 infections was identified as the Amblyomma triste tick, a Neotropical species only recently recognized in the United States. Identification of R. parkeri rickettsiosis in southern Arizona demonstrates a need for local ecologic and epidemiologic assessments to better understand geographic distribution and define public health risk. Education and outreach aimed at persons recreating or working in this region of southern Arizona would improve awareness and promote prevention of tickborne rickettsioses.

  6. The Uneven Performance of Arizona's Charter Schools

    Science.gov (United States)

    Chingos, Matthew M.; West, Martin R.

    2015-01-01

    Arizona enrolls a larger share of its students in charter schools than any other state in the country, but no comprehensive examination exists of the impact of those schools on student achievement. Using student-level data covering all Arizona students from 2006 to 2012, we find that the performance of charter schools in Arizona in improving…

  7. Climate sensitivity of shrub growth across the tundra biome

    DEFF Research Database (Denmark)

    Myers-Smith, Isla H.; Elmendorf, Sarah C.; Beck, Pieter S.A.

    2015-01-01

    Rapid climate warming in the tundra biome has been linked to increasing shrub dominance1–4. Shrub expansion can modify climate by altering surface albedo, energy and water balance, and permafrost2,5–8, yet the drivers of shrub growth remain poorly understood. Dendroecological data consisting...... of multi-decadal time series of annual shrub growth provide an underused resource to explore climate–growth relationships. Here, we analyse circumpolar data from 37 Arctic and alpine sites in 9 countries, including 25 species, and 42,000 annual growth records from 1,821 individuals. Our analyses...... demonstrate that the sensitivity of shrub growth to climate was: (1) heterogeneous, with European sites showing greater summer temperature sensitivity than North American sites, and (2) higher at sites with greater soil moisture and for taller shrubs (for example, alders and willows) growing at their northern...

  8. Vegetation stability and the habitat associations of the endemic taxa of the Olympic Peninsula, Washington, USA

    Directory of Open Access Journals (Sweden)

    Daniel G. Gavin

    2015-07-01

    Full Text Available Explanations for areas of endemism often involve relative climatic stability, or low climate velocity, over time scales ranging from the Pleistocene to the late Cenozoic. Given that many narrowly endemic taxa in forested landscapes display discrete habitat associations, habitat stability should be similarly important for endemic persistence. Furthermore, while past climate variability is exceedingly difficult to quantify on millennial time scales, past distributions of habitats may be robustly inferred from paleoecological records. The Olympic Peninsula, Washington, supports a biota with several insular features including 29 endemic plant and animal taxa. Here I present the geographic distribution and habitat of the endemic taxa, and then examine the vegetation stability of the past 14,300 years from five pollen records associated with discrete vegetation zones on the peninsula. I show that 11 endemics have distributions centered on dry alpine scree and rock in the northeastern quadrant of the peninsula, and nine occur in shaded riparian forests in the southwest. Vegetation turnover during the post-glacial period was smallest in these areas. However, another long pollen record from the western peninsula reveals existence of shrub tundra and greatly reduced forest cover, indicating southward displacement of shaded riparian habitats by perhaps as much as 100 km. Although this study supports an association of post-glacial vegetation stability with endemism, records spanning the glacial maximum indicate widespread tundra during long periods of the late Pleistocene and therefore suggest southern displacement of forest-associated endemics. While some of the alpine scree-associated endemics may have persisted in situ, many others likely arrived via a variety of dispersal trajectories. These histories include dispersal from southern refugia towards ocean barriers preventing further northward dispersal, contraction from more widespread distributions, and

  9. Small mammals as indicators of cryptic plant species diversity in the central Chilean plant endemicity hotspot

    Directory of Open Access Journals (Sweden)

    Meredith Root-Bernstein

    2014-12-01

    Full Text Available Indicator species could help to compensate for a shortfall of knowledge about the diversity and distributions of undersampled and cryptic species. This paper provides background knowledge about the ecological interactions that affect and are affected by herbaceous diversity in central Chile, as part of the indicator species selection process. We focus on the ecosystem engineering role of small mammals, primarily the degu Octodon degus. We also consider the interacting effects of shrubs, trees, avian activity, livestock, slope, and soil quality on herbaceous communities in central Chile. We sampled herbaceous diversity on a private landholding characterized by a mosaic of savanna, grassland and matorral, across a range of degu disturbance intensities. We find that the strongest factors affecting endemic herbaceous diversity are density of degu runways, shrub cover and avian activity. Our results show that the degu, a charismatic and easily identifiable and countable species, could be used as an indicator species to aid potential conservation actions such as private protected area uptake. We map areas in central Chile where degus may indicate endemic plant diversity. This area is larger than expected, and suggests that significant areas of endemic plant communities may still exist, and should be identified and protected. Keywords: Cryptic species, Diversity, Endemic, Indicator species, Octodon degus, Plant

  10. Shrubs of the Field Irradiator - Gamma area in eastern Manitoba

    International Nuclear Information System (INIS)

    Dugle, J.R.; Mayoh, K.R.; Barclay, P.J.

    1979-11-01

    Detailed descriptions and line drawings are given of over 100 shrub taxa (including semi-woody shrubs and vines) which are common in Manitoba; most of them are found within the Field Irradiator - Gamma (FIG) area or its immediate surroundings. Ecological and morphological notes are included along with a few general remarks on the effects of exposure to long-term gamma radiation. Keys are given for certain genera, small family groups or other critical species groups. This document is intended to facilitate identification of shrubs for experimental purposes in the FIG projects, and it should also be useful to those who are generally interested in the shrubs of Manitoba. (auth)

  11. Argumentation in Miranda v. Arizona.

    Science.gov (United States)

    Benoit, William L.

    1991-01-01

    Investigates the argumentation advanced in briefs, oral arguments, and the Supreme Court's opinion in the case of Miranda versus Arizona. Considers the background of the case, analyzes the argumentation and its influences on the court, and stresses the importance of viewing the Supreme Court as an active participant in the decision-making process.…

  12. Boots on the Ground: Arizona

    Centers for Disease Control (CDC) Podcasts

    2013-12-26

    In this podcast, we talk to CDC public health advisor Lisa Speissegger about her response efforts during the 2013 Arizona wildfires.  Created: 12/26/2013 by Office of Public Health Preparedness and Response (PHPR).   Date Released: 12/26/2013.

  13. Residential Energy Efficiency Potential: Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Eric J [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-11-16

    Energy used by Arizona single-family homes that can be saved through cost-effective improvements. Prepared by Eric Wilson and Noel Merket, NREL, and Erin Boyd, U.S. Department of Energy Office of Energy Policy and Systems Analysis.

  14. A Melioidosis Case in Arizona

    Centers for Disease Control (CDC) Podcasts

    2011-10-03

    David Blaney, Medical Officer, Bacterial Special Pathogens Branch, discusses an unusual melioidosis case in Arizona.  Created: 10/3/2011 by National Center for Emerging Zoonotic and Infectious Diseases (NCEZID).   Date Released: 10/5/2011.

  15. Arizona TeleMedicine Project.

    Science.gov (United States)

    Arizona Univ., Tucson. Coll. of Medicine.

    Designed to provide health services for American Indians living on rurally isolated reservations, the Arizona TeleMedicine Project proposes to link Phoenix and Tucson medical centers, via a statewide telecommunications system, with the Hopi, San Carlos Apache, Papago, Navajo, and White Mountain Apache reservations. Advisory boards are being…

  16. Comparative wood anatomy of some shrubs native to the Northern Rocky Mountains

    Science.gov (United States)

    Arlene Dale

    1968-01-01

    This paper describes some xylem characteristics of the more important shrub species of the Northern Rockies and presents a key for identifying shrub-wood specimens by microscopic characters. The paper contains photomicrographs of 55 shrub woods.

  17. Patterns of seed production and shrub association in two palatable ...

    African Journals Online (AJOL)

    Seed production and shrub association patterns of the twopalatable shrubs. Tripteris sinuatum and Tetragoma froticosa were investigated on heavily grazed communal and lightly grazed commercial rangeland in the succulent karoo. Namaqualand. Seed production in both these species was substantially reduced on the ...

  18. Shrub expansion may reduce summer permafrost thaw in Siberian tundra

    NARCIS (Netherlands)

    Blok, D.; Heijmans, M.M.P.D.; Schaepman-Strub, G.; Kononov, A.V.; Maximov, T.C.; Berendse, F.

    2010-01-01

    Climate change is expected to cause extensive vegetation changes in the Arctic: deciduous shrubs are already expanding, in response to climate warming. The results from transect studies suggest that increasing shrub cover will impact significantly on the surface energy balance. However, little is

  19. Relationships between Arctic shrub dynamics and topographically derived hydrologic characteristics

    International Nuclear Information System (INIS)

    Naito, Adam T; Cairns, David M

    2011-01-01

    Shrub expansion is a global phenomenon that is gaining increased attention in the Arctic. Recent work employing the use of oblique aerial photographs suggested a consistent pattern of positive change in shrub cover across the North Slope of Alaska. The greatest amounts of change occurred in valley slopes and floodplains. We studied the association between shrub cover change and topographically derived hydrologic characteristics in five areas in northern Alaska between the 1970s and 2000s. Change in total shrub cover ranged from − 0.65% to 46.56%. Change in floodplain shrub cover ranged from 3.38% to 76.22%. Shrubs are preferentially expanding into areas of higher topographic wetness index (TWI) values where the potential for moisture accumulation or drainage is greater. In addition, we found that floodplain shrub development was strongly associated with high TWI values and a decreasing average distance between shrubs and the river bank. This suggests an interacting influence of substrate removal and stabilization as a consequence of increased vegetation cover.

  20. Methods for measuring arctic and alpine shrub growth: A review

    NARCIS (Netherlands)

    Myers-Smith, I.H.; Hallinger, M.; Blok, D.; Sass-Klaassen, U.G.W.; Rayback, S.A.

    2015-01-01

    Shrubs have increased in abundance and dominance in arctic and alpine regions in recent decades. This often dramatic change, likely due to climate warming, has the potential to alter both the structure and function of tundra ecosystems. The analysis of shrub growth is improving our understanding of

  1. Variation in woody plant mortality and dieback from severe drought among soils, plant groups, and species within a northern Arizona ecotone.

    Science.gov (United States)

    Koepke, Dan F; Kolb, Thomas E; Adams, Henry D

    2010-08-01

    Vegetation change from drought-induced mortality can alter ecosystem community structure, biodiversity, and services. Although drought-induced mortality of woody plants has increased globally with recent warming, influences of soil type, tree and shrub groups, and species are poorly understood. Following the severe 2002 drought in northern Arizona, we surveyed woody plant mortality and canopy dieback of live trees and shrubs at the forest-woodland ecotone on soils derived from three soil parent materials (cinder, flow basalt, sedimentary) that differed in texture and rockiness. Our first of three major findings was that soil parent material had little effect on mortality of both trees and shrubs, yet canopy dieback of trees was influenced by parent material; dieback was highest on the cinder for pinyon pine (Pinus edulis) and one-seed juniper (Juniperus monosperma). Ponderosa pine (Pinus ponderosa) dieback was not sensitive to parent material. Second, shrubs had similar mortality, but greater canopy dieback, than trees. Third, pinyon and ponderosa pines had greater mortality than juniper, yet juniper had greater dieback, reflecting different hydraulic characteristics among these tree species. Our results show that impacts of severe drought on woody plants differed among tree species and tree and shrub groups, and such impacts were widespread over different soils in the southwestern U.S. Increasing frequency of severe drought with climate warming will likely cause similar mortality to trees and shrubs over major soil types at the forest-woodland ecotone in this region, but due to greater mortality of other tree species, tree cover will shift from a mixture of species to dominance by junipers and shrubs. Surviving junipers and shrubs will also likely have diminished leaf area due to canopy dieback.

  2. Impaired Water 303(d) Polygons, Arizona, 2004, Arizona Department of Environmental Quality

    Data.gov (United States)

    U.S. Environmental Protection Agency — Arizona 303(d) waterbodies for 2004. These include lakes, reservoirs, ponds, etc. The 303(d) list is a related table to the feature class AZ_303d_04_area. Arizona's...

  3. NORTH END ROADLESS AREA, ARIZONA.

    Science.gov (United States)

    Drewes, Harald; Bigsby, P.R.

    1984-01-01

    Studies conducted in the North End Roadless Area, Arizona indicate probable or substantiated metallic mineral-resource potential in about one-fifth of the area. The area has potential for disseminated or stockwork-type molybdenum mineralization, copper-lead-zinc-silver veins, lead-zinc-silver limestone replacement deposits, and tungsten-bearing contact metamorphic skarn deposits. The area also contains cement rock and marble dimension stone, but has only slight promise for the occurrence of petroleum and natural gas.

  4. The changing role of shrubs in rangeland-based livestock production systems: Can shrubs increase our forage supply?

    Science.gov (United States)

    Projected global increases in ruminant numbers and loss of native grasslands will present a number of challenges for livestock agriculture. Escalated demand for livestock products may stimulate interest in using shrubs on western rangelands. A paradigm shift is needed to change the role of shrubs in...

  5. The endemic flora of Greece

    DEFF Research Database (Denmark)

    Tan, Kit

    2007-01-01

    The Balkan Peninsula has a rich endemic flora estimated as between 2600 and 2700 taxa; c. 750 are restricted to Greece. Conservationists consider the endemic flora of a country needs protection for all time; there is a tendency to paint an alarming picture. However, unless one knows something or ...... have been mapped and it is already possible to recognize the hot-spots of biodiversity as these are linked to the centres of endemism. Determining the centres of diversity is an important and significant contribution to further conservation measures at the global level....

  6. 76 FR 28210 - Eastern Arizona Counties Resource Advisory Committee

    Science.gov (United States)

    2011-05-16

    ... DEPARTMENT OF AGRICULTURE Forest Service Eastern Arizona Counties Resource Advisory Committee AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Eastern Arizona Counties will meet...: Julia Faith Rivera, RAC Program Manager, Eastern Arizona Counties Resource Advisory Committee, Apache...

  7. 76 FR 41755 - Eastern Arizona Counties Resource Advisory; Meeting

    Science.gov (United States)

    2011-07-15

    ... DEPARTMENT OF AGRICULTURE Forest Service Eastern Arizona Counties Resource Advisory; Meeting AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Eastern Arizona Counties Resource... FURTHER INFORMATION CONTACT: Julia Faith Rivera, RAC Program Manager, Eastern Arizona Counties Resource...

  8. Does browsing reduce shrub survival and vigor following summer fires?

    Science.gov (United States)

    Fulbright, Timothy E.; Dacy, Emily C.; Drawe, D. Lynn

    2011-01-01

    Periodic fire is widely hypothesized to limit woody plant encroachment in semiarid grasslands. In southern Texas, however, most of the woody plants that have invaded grasslands during the past two centuries are resistant to fire. We hypothesized that browsing by Odocoileus virginianus increases mortality of palatable shrubs and reduces vigor of shrubs following fire. We randomly selected ten pairs of each of three shrub species -Condalia hookeri, Acacia farnesiana, and Celtis ehrenbergiana - in each of three locations before prescribed burns during summer 2001. Following burns, we used a wire fence to protect one shrub of each pair from browsing. We estimated intensity of O. virginianus browsing and number and height of sprouts 4, 12, 20, 30, 38, and 47 weeks post-fire. We determined shrub height, survival, and biomass one year post-fire. Averaged across species, browsing intensity on unfenced shrubs was greater (LS Means, P 0.05) one year post-burn. Browsing by O. virginianus at the intensity in our study does not increase mortality or reduce vigor of C. hookeri, A. farnesiana, and Condalia ehrenbergiana producing new growth following destruction of aboveground tissues by a single fire compared to shrubs that are not browsed following fire.

  9. 77 FR 51966 - Eastern Arizona Resource Advisory Committee

    Science.gov (United States)

    2012-08-28

    ... DEPARTMENT OF AGRICULTURE Forest Service Eastern Arizona Resource Advisory Committee AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Eastern Arizona Resource Advisory Committee...

  10. Spatial analysis of root hemiparasitic shrubs and their hosts

    DEFF Research Database (Denmark)

    Dueholm, Bjørn; Bruce, David; Weinstein, Philip

    2017-01-01

    to as spatial signatures of the root hemiparasites. In order to search for such spatial signatures, we investigated a population of a predominant Acacia species in Australia co-occurring with established root hemiparasitic shrubs, using intensity estimates of the Acacia and dead shrubs to be indicators...... of parasite populations. We find evidence that the root hemiparasitic shrubs, like herbaceous root hemiparasites, prefer growing at distances from neighbouring plants that fulfil resource requirements both below-ground and above-ground. Assuming that root hemiparasites are limited by their hosts, we present...

  11. Influence of summer marine fog and low cloud stratus on water relations of evergreen woody shrubs (Arctostaphylos: Ericaceae) in the chaparral of central California.

    Science.gov (United States)

    Vasey, Michael C; Loik, Michael E; Parker, V Thomas

    2012-10-01

    Mediterranean-type climate (MTC) regions around the world are notable for cool, wet winters and hot, dry summers. A dominant vegetation type in all five MTC regions is evergreen, sclerophyllous shrubland, called chaparral in California. The extreme summer dry season in California is moderated by a persistent low-elevation layer of marine fog and cloud cover along the margin of the Pacific coast. We tested whether late dry season water potentials (Ψ(min)) of chaparral shrubs, such as Arctostaphylos species in central California, are influenced by this coast-to-interior climate gradient. Lowland coastal (maritime) shrubs were found to have significantly less negative Ψ(min) than upland interior shrubs (interior), and stable isotope (δ(13)C) values exhibited greater water use efficiency in the interior. Post-fire resprouter shrubs (resprouters) had significantly less negative Ψ(min) than co-occurring obligate seeder shrubs (seeders) in interior and transitional chaparral, possibly because resprouters have deeper root systems with better access to subsurface water than shallow-rooted seeders. Unexpectedly, maritime resprouters and seeders did not differ significantly in their Ψ(min), possibly reflecting more favorable water availability for shrubs influenced by the summer marine layer. Microclimate and soil data also suggest that maritime habitats have more favorable water availability than the interior. While maritime seeders constitute the majority of local Arctostaphylos endemics, they exhibited significantly greater vulnerability to xylem cavitation than interior seeders. Because rare seeders in maritime chaparral are more vulnerable to xylem cavitation than interior seeders, the potential breakdown of the summer marine layer along the coast is of potential conservation concern.

  12. Biogeography of amphibians and reptiles in Arizona

    Science.gov (United States)

    Eric W. Stitt; Theresa M. Mau-Crimmins; Don E. Swann

    2005-01-01

    We examined patterns of species richness for amphibians and reptiles in Arizona and evaluated patterns in species distribution between ecoregions based on species range size. In Arizona, the Sonoran Desert has the highest herpetofauna diversity, and the southern ecoregions are more similar than other regions. There appear to be distinct low- and mid-elevational...

  13. Mean species cover: a harmonized indicator of shrub cover for forest inventories

    Science.gov (United States)

    Iciar Alberdi; Sonia Condés; Ronald E. Mcroberts; Susanne Winter

    2018-01-01

    Because shrub cover is related to many forest ecosystem functions, it is one of the most relevant variables for describing these communities. Nevertheless, a harmonized indicator of shrub cover for large-scale reporting is lacking. The aims of the study were threefold: to define a shrub indicator that can be used by European countries for harmonized shrub cover...

  14. Shrubs of California's chaparral, timberland, and wood land: area, ownership, and stand characteristics.

    Science.gov (United States)

    Charles L. Boisinger

    1988-01-01

    A statewide inventory of shrubs in chaparral and on timberland and woodland in California is presented, and the relevance of shrubs to resource management is discussed. Shrub types (excluding coastal sage and Great Basin and desert shrubs) cover about 10 million acres, 73 percent of which is chaparral. Chamise is the most widespread type in chaparral (51 percent of...

  15. IMPACTS ON FLOODPLAINS BY AN INVASIVE SHRUB, BUDDLEJA DAVIDII

    Science.gov (United States)

    Despite its popularity, the ornamental, Buddleja davidii, a woody shrub of Asian origin, is considered problematic because of its ability to rapidly colonize and dominate floodplain and riparian ecosystems. Dominance during early succession may influence community dynamics and ec...

  16. Methods for measuring arctic and alpine shrub growth

    DEFF Research Database (Denmark)

    Myers-Smith, Isla; Hallinger, Martin; Blok, Daan

    2015-01-01

    Shrubs have increased in abundance and dominance in arctic and alpine regions in recent decades. This often dramatic change, likely due to climate warming, has the potential to alter both the structure and function of tundra ecosystems. The analysis of shrub growth is improving our understanding...... of tundra vegetation dynamics and environmental changes. However, dendrochronological methods developed for trees, need to be adapted for the morphology and growth eccentricity of shrubs. Here, we review current and developing methods to measure radial and axial growth, estimate age, and assess growth...... dynamics in relation to environmental variables. Recent advances in sampling methods, analysis and applications have improved our ability to investigate growth and recruitment dynamics of shrubs. However, to extrapolate findings to the biome scale, future dendroecologicalwork will require improved...

  17. Shrub expansion in SW Greenland under modest regional warming

    DEFF Research Database (Denmark)

    Jørgensen, Rasmus Halfdan; Meilby, Henrik; Kollmann, Johannes

    2013-01-01

    Shrub expansion has been observed widely in tundra areas across the Arctic. This phenomenon has been partially attributed to increasing temperatures over the past century. However, relationships among shrub expansion, grazing, and human disturbance have been studied little. SW Greenland...... is a subarctic to low-arctic region with a long and complex land-use history and only modest temperature increases over the past 50 years (0.2 °C decade-1), but changes in shrub cover have not previously been studied in this region. We compiled historical photographs of vegetation in SW Greenland (1898......–1974) and repeated the photos in 2010 and 2011. Sixty-four photo pairs were cropped into 133 smaller units and classified by aspect, substrate stability, muskoxen grazing, and human disturbance. The photo material was evaluated by 22 experts with respect to changes in shrub cover, revealing a general increase across...

  18. Species Diversity Distribution Patterns of Chinese Endemic Seed Plants Based on Geographical Regions.

    Science.gov (United States)

    Huang, Jihong; Ma, Keping; Huang, Jianhua

    2017-01-01

    Based on a great number of literatures, we established the database about the Chinese endemic seed plants and analyzed the compositions, growth form, distribution and angiosperm original families of them within three big natural areas and seven natural regions. The results indicate that the above characters of Chinese endemic plants take on relative rule at the different geographical scales. Among the three big natural areas, Eastern Monsoon area has the highest endemic plants richness, whereas Northwest Dryness area is the lowest. For life forms, herbs dominate. In contrast, the proportion of herbs of Eastern Monsoon area is remarkable under other two areas. Correspondingly the proportions of trees and shrubs are substantially higher than other two. For angiosperm original families, the number is the highest in Eastern Monsoon area, and lowest in Northwest Dryness area. On the other hand, among the seven natural regions, the humid and subtropical zone in Central and Southern China has the highest endemic plants richness, whereas the humid, hemi-humid region and temperate zone in Northeast China has the lowest. For life forms, the proportion of herbs tends to decrease from humid, hemi-humid region and temperate zone in Northeast China to humid and tropical zone in Southern China. Comparably, trees, shrubs and vines or lianas increase with the same directions. This fully represents these characters of Chinese endemic plants vary with latitudinal gradients. Furthermore, as to the number of endemic plants belonging to angiosperm original families, the number is the most in humid and subtropical zone in Center and Southern China, and tropical zone in Southern China in the next place. In contrast, the endemic plant of these two regions relatively is richer than that of The Qinghai-Tibet alpine and cold region. All above results sufficiently reflect that the Chinese endemic plants mainly distribute in Eastern Monsoon area, especially humid and subtropical zone in Center

  19. Enhanced precipitation variability decreases grass- and increases shrub-productivity

    Science.gov (United States)

    Gherardi, Laureano A.; Sala, Osvaldo E.

    2015-01-01

    Although projections of precipitation change indicate increases in variability, most studies of impacts of climate change on ecosystems focused on effects of changes in amount of precipitation, overlooking precipitation variability effects, especially at the interannual scale. Here, we present results from a 6-y field experiment, where we applied sequences of wet and dry years, increasing interannual precipitation coefficient of variation while maintaining a precipitation amount constant. Increased precipitation variability significantly reduced ecosystem primary production. Dominant plant-functional types showed opposite responses: perennial-grass productivity decreased by 81%, whereas shrub productivity increased by 67%. This pattern was explained by different nonlinear responses to precipitation. Grass productivity presented a saturating response to precipitation where dry years had a larger negative effect than the positive effects of wet years. In contrast, shrubs showed an increasing response to precipitation that resulted in an increase in average productivity with increasing precipitation variability. In addition, the effects of precipitation variation increased through time. We argue that the differential responses of grasses and shrubs to precipitation variability and the amplification of this phenomenon through time result from contrasting root distributions of grasses and shrubs and competitive interactions among plant types, confirmed by structural equation analysis. Under drought conditions, grasses reduce their abundance and their ability to absorb water that then is transferred to deep soil layers that are exclusively explored by shrubs. Our work addresses an understudied dimension of climate change that might lead to widespread shrub encroachment reducing the provisioning of ecosystem services to society. PMID:26417095

  20. Patterned-ground facilitates shrub expansion in Low Arctic tundra

    International Nuclear Information System (INIS)

    Frost, Gerald V; Epstein, Howard E; Walker, Donald A; Matyshak, Georgiy; Ermokhina, Ksenia

    2013-01-01

    Recent expansion of tall shrubs in Low Arctic tundra is widely seen as a response to climate warming, but shrubification is not occurring as a simple function of regional climate trends. We show that establishment of tall alder (Alnus) is strongly facilitated by small, widely distributed cryogenic disturbances associated with patterned-ground landscapes. We identified expanding and newly established shrub stands at two northwest Siberian sites and observed that virtually all new shrubs occurred on bare microsites (‘circles’) that were disturbed by frost-heave. Frost-heave associated with circles is a widespread, annual phenomenon that maintains mosaics of mineral seedbeds with warm soils and few competitors that are immediately available to shrubs during favorable climatic periods. Circle facilitation of alder recruitment also plausibly explains the development of shrublands in which alders are regularly spaced. We conclude that alder abundance and extent have increased rapidly in the northwest Siberian Low Arctic since at least the mid-20th century, despite a lack of summer warming in recent decades. Our results are consistent with findings in the North American Arctic which emphasize that the responsiveness of Low Arctic landscapes to climate change is largely determined by the frequency and extent of disturbance processes that create mineral-rich seedbeds favorable for tall shrub recruitment. Northwest Siberia has high potential for continued expansion of tall shrubs and concomitant changes to ecosystem function, due to the widespread distribution of patterned-ground landscapes. (letter)

  1. Composition, Endemism and Phytogeographical Affinities of the Taiwan Flora

    Directory of Open Access Journals (Sweden)

    Chang-Fu Hsieh

    2002-12-01

    Full Text Available The Taiwan vascular flora is exceptionally interesting not only because it is rich and diversified, but because it is of great phytogeographic significance owing to its geographic location. The flora of Taiwan, including naturalized plants, comprises 233 families and 1389 genera with 4216 species. In terms of major growth forms, there are 588 trees, 426 shrubs, 249 lianas, 177 vines, and 2776 herbs or ferns. Approximately 234 species are exotics typically associated with pastures, road clearings and other human disturbances. An extremely large percentage of these naturalized plants are of tropical New World origin. Among the native flora, the Orchidaceae (331 species, Gramineae (249, Compositae (194, Leguminosae (176, Cyperaceae (174, Rosaceae (105, Rubiaceae (93 and Euphorbiaceae (76 rank highest in numbers of species. Clearly, the greatest part of Taiwan's floristics richness comes from a wealth of species in primarily lowland (0–600 m asl. taxa. A total of 2571 species were recorded in the lowlands, whereas only about 251 species occur between 3100-3950 m. Endemic genera are extremely scarce in Taiwan, with only four, namely Sinopanax (Araliaceae, Hayatella (Rubiaceae, Kudoacanthus (Acanthaceae, and Haraella (Orchidaceae. In contrast to the low percentage of generic endemism, there is a remarkably higher specific endemism. About 1041 species (26.1% of indigenous plants are known only from Taiwan. A detailed examination of these species shows that there is a distinct trend of increasing endemism with increasing altitude (r² = 0.99. A survey of indigenous non-endemic species on the basis of their geographical distribution outside Taiwan shows that they can be classified into 6 major categories: 1. pantropical and palaeotropical species (1029 species; 2. species distributed in eastern Asia, from Himalayas through southern & eastern China to Taiwan, with some extending to the Ryukyus and Japan (1075 species; 3. widespread species extending

  2. Do changes in grazing pressure and the degree of shrub encroachment alter the effects of individual shrubs on understorey plant communities and soil function?

    Science.gov (United States)

    Soliveres, Santiago; Eldridge, David J

    2014-04-01

    Shrub canopies in semi-arid environments often produce positive effects on soil fertility, and on the richness and biomass of understorey plant communities. However, both positive and negative effects of shrub encroachment on plant and soil attributes have been reported at the landscape-level. The contrasting results between patch- and landscape-level effects in shrublands could be caused by differences in the degree of shrub encroachment or grazing pressure, both of which are likely to reduce the ability of individual shrubs to ameliorate their understorey environment.We examined how grazing and shrub encroachment (measured as landscape-level shrub cover) influence patch-level effects of shrubs on plant density, biomass and similarity in species composition between shrub understories and open areas, and on soil stability, nutrient cycling, and infiltration in two semi-arid Australian woodlands.Individual shrubs had consistently positive effects on all plant and soil variables (average increase of 23% for all variables). These positive patch-level effects persisted with increasing shrub cover up to our maximum of 50% cover. Heavy grazing negatively affected most of the variables studied (average decline of 11%). It also altered, for some variables, how individual shrubs affected their sub-canopy environment with increasing shrub cover. Thus for species density, biomass and soil infiltration, the positive effect of individual shrubs with increasing shrub cover diminished under heavy grazing. Our study refines predictions of the effects of woody encroachment on ecosystem structure and functioning by showing that heavy grazing, rather than differences in shrub cover, explains the contrasting effects on ecosystem structure and function between individual shrubs and those in dense aggregations. We also discuss how species-specific traits of the encroaching species, such as their height or its ability to fix N, might influence the relationship between their patch

  3. Permafrost response to increasing Arctic shrub abundance depends on the relative influence of shrubs on local soil cooling versus large-scale climate warming

    International Nuclear Information System (INIS)

    Lawrence, David M; Swenson, Sean C

    2011-01-01

    Deciduous shrub abundance is increasing across the Arctic in response to climatic warming. In a recent field manipulation experiment in which shrubs were removed from a plot and compared to a control plot with shrubs, Blok et al (2010 Glob. Change Biol. 16 1296–305) found that shrubs protect the ground through shading, resulting in a ∼ 9% shallower active layer thickness (ALT) under shrubs compared to grassy-tundra, which led them to argue that continued Arctic shrub expansion could mitigate future permafrost thaw. We utilize the Community Land Model (CLM4) coupled to the Community Atmosphere Model (CAM4) to evaluate this hypothesis. CLM4 simulates shallower ALT (∼− 11 cm) under shrubs, consistent with the field manipulation study. However, in an idealized pan-Arctic + 20% shrub area experiment, atmospheric heating, driven mainly by surface albedo changes related to protrusion of shrub stems above the spring snowpack, leads to soil warming and deeper ALT (∼+ 10 cm). Therefore, if climate feedbacks are considered, shrub expansion may actually increase rather than decrease permafrost vulnerability. When we account for blowing-snow redistribution from grassy-tundra to shrubs, shifts in snowpack distribution in low versus high shrub area simulations counter the climate warming impact, resulting in a grid cell mean ALT that is unchanged. These results reinforce the need to consider vegetation dynamics and blowing-snow processes in the permafrost thaw model projections.

  4. Water storage capacity, stemflow and water funneling in Mediterranean shrubs

    Science.gov (United States)

    Garcia-Estringana, P.; Alonso-Blázquez, N.; Alegre, J.

    2010-08-01

    SummaryTo predict water losses and other hydrological and ecological features of a given vegetation, its water storage capacity and stemflow need to be accurately determined. Vast areas of the Mediterranean region are occupied by shrublands yet there is scarce data available on their rainwater interception capacity. In this study, simulated rainfall tests were conducted in controlled conditions on nine Mediterranean shrubs of varying anatomic and morphological features to determine water storage capacity, stemflow and the funneling ratio. After assessing correlations between these hydrological variables and the biometric characteristics of the shrubs, we compared two methods of determining storage capacity: rainfall simulation and immersion. Mean water storage capacity was 1.02 mm (0.35-3.24 mm), stemflow was 16% (3.8-26.4%) and the funneling ratio was 104 (30-260). Per unit biomass, mean storage capacity was 0.66 ml g -1 and ranged from 0.23 ml g -1 for Cistus ladanifer to 2.26 ml g -1 for Lavandula latifolia. Despite their small size, shrubs may generate high water losses to the atmosphere when they form dense communities and this can have a significant impact in regions where water is scarce. When considered the whole shrubs in absolute terms (ml per plant), water storage capacity and stemflow were correlated to biomass and the dendrometric characteristics of the shrubs, yet in relative terms (expressed per surface area unit or as %), anatomic features such as pubescence, branch rigidity or leaf insertion angle emerged as determining factors. The use of a simple procedure to assess storage capacity was inefficient. The immersion method underestimated storage capacity to a different extent for each species. Some shrubs returned high stemflow values typical of their adaptation to the semiarid climate. In contrast, other shrubs seem to have structures that promote stemflow yet have developed other drought-adaptation mechanisms. In this report, we discuss the

  5. Facilitating the afforestation of Mediterranean polluted soils by nurse shrubs.

    Science.gov (United States)

    Domínguez, María T; Pérez-Ramos, Ignacio M; Murillo, José M; Marañón, Teodoro

    2015-09-15

    The revegetation of polluted sites and abandoned agricultural soils is critical to reduce soil losses and to control the spread of soil pollution in the Mediterranean region, which is currently exposed to the greatest soil erosion risk in Europe. However, events of massive plant mortality usually occur during the first years after planting, mainly due to the adverse conditions of high irradiance and drought stress. Here, we evaluated the usefulness of considering the positive plant-plant interactions (facilitation effect) in the afforestation of polluted agricultural sites, using pre-existing shrubs as nurse plants. We used nurse shrubs as planting microsites for acorns of Quercus ilex (Holm oak) along a gradient of soil pollution in southwestern Spain, and monitored seedling growth, survival, and chemical composition during three consecutive years. Seedling survival greatly increased (from 20% to more than 50%) when acorns were sown under shrub, in comparison to the open, unprotected matrix. Facilitation of seedling growth by shrubs increased along the gradient of soil pollution, in agreement with the stress gradient hypothesis that predicts higher intensity of the facilitation effects with increasing abiotic stress. Although the accumulation of trace elements in seedling leaves was higher underneath shrub, the shading conditions provided by the shrub canopy allowed seedlings to cope with the toxicity provoked by the concurrence of low pH and high trace element concentrations in the most polluted sites. Our results show that the use of shrubs as nurse plants is a promising tool for the cost-effective afforestation of polluted lands under Mediterranean conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Coccidiodomycosis in Arizona 2007-2008

    Centers for Disease Control (CDC) Podcasts

    This podcast looks at the impact of Coccidioidomycosis, or Valley Fever, in Arizona in 2007 and early 2008. CDC epidemiologist Dr. Tom Chiller discusses what researchers learned about this fungal disease.

  7. March 2014 Arizona thoracic society notes

    OpenAIRE

    Robbins RA

    2014-01-01

    No abstract available. Article truncated after 150 words. The March 2014 Arizona Thoracic Society meeting was a special meeting. In conjunction with the Valley Fever Center for Excellence and the Arizona Respiratory Center the Eighteenth Annual Farness Lecture was held in the Sonntag Pavilion at St. Joseph's Hospital at 6 PM on Friday, April 4, 2014. The guest speaker was Antonio "Tony" Catanzaro, MD from the University of California San Diego and current president of the Cocci Study Group. T...

  8. Mammal endemism In Italy: A review

    Directory of Open Access Journals (Sweden)

    Giovanni Amori

    2018-02-01

    Full Text Available Although there are various checklists of Italian mammals, there is not yet a synthesis of those mammals that are endemic to Italy. Therefore, we provide for the first time a detailed review on Italian mammal endemic species including endemic taxa deserving additional studies. This review is based on the most recent taxonomic revisions obtained using Scopus and Google Scholar databases. We also considered the age of endemic species. Some aspects of mammalian conservation are also provided and discussed.

  9. Sediment budgets and source determinations using fallout Cesium-137 in a semiarid rangeland watershed, Arizona, USA

    International Nuclear Information System (INIS)

    Ritchie, Jerry C.; Nearing, Mark A.; Rhoton, Fred E.

    2009-01-01

    Analysis of soil redistribution and sediment sources in semiarid and arid watersheds provides information for implementing management practices to improve rangeland conditions and reduce sediment loads to streams. The purpose of this research was to develop sediment budgets and identify potential sediment sources using 137 Cs and other soil properties in a series of small semiarid subwatersheds on the USDA ARS Walnut Gulch Experimental Watershed near Tombstone, Arizona, USA. Soils were sampled in a grid pattern on two small subwatersheds and along transects associated with soils and geomorphology on six larger subwatersheds. Soil samples were analyzed for 137 Cs and selected physical and chemical properties (i.e., bulk density, rocks, particle size, soil organic carbon). Suspended sediment samples collected at measuring flume sites on the Walnut Gulch Experimental Watershed were also analyzed for these properties. Soil redistribution measured using 137 Cs inventories for a small shrub-dominated subwatershed and a small grass-dominated subwatershed found eroding areas in these subwatersheds were losing -5.6 and -3.2 t ha -1 yr -1 , respectively; however, a sediment budget for each of these subwatersheds, including depositional areas, found net soil loss to be -4.3 t ha -1 yr -1 from the shrub-dominated subwatershed and -0.1 t ha -1 yr -1 from the grass-dominated subwatershed. Generally, the suspended sediment collected at the flumes of the six other subwatersheds was enriched in silt and clay. Using a mixing model to determine sediment source indicated that shrub-dominated subwatersheds were contributing most of the suspended sediment that was measured at the outlet flume of the Walnut Gulch Experimental Watershed. The two methodologies (sediment budgets and sediment source analyses) indicate that shrub-dominated systems provide more suspended sediment to the stream systems. The sediment budget studies also suggest that sediment yields measured at the outlet of a

  10. Endemic Images and the Desensitization Process.

    Science.gov (United States)

    Saigh, Philip A.; Antoun, Fouad T.

    1984-01-01

    Examined the effects of endemic images on levels of anxiety and achievement of 48 high school students. Results suggested that a combination of endemic images and study skills training was as effective as desensitization plus study skills training. Includes the endemic image questionnaire. (JAC)

  11. Effects of Mediterranean shrub species on rainfall interception

    International Nuclear Information System (INIS)

    Garcia-Estringana, P.; Alonso-Blazquez, N.; Marques, M. J.; Bienes, R.; Alegre, J.

    2009-01-01

    Rainfall is intercepted by vegetation. Water intercepted could be evaporated, or it could drip from the leaves and stems to the soil or it could run down the stems to the base of the plant. In the Mediterranean, where water is a scant resource, interception loss could have an influence on hydrology. Water storage capacity depends on vegetation type. In the Mediterranean, there are many types of shrubs, and many of them are able to intercept large volumes of water depending on the shrub type. many lands of the Mediterranean basin of Europea Union have been abandoned in the last decades and consequently vegetation type changes too. This modifies hydrologic processes, changing the volume and the way in which the rainfall reaches the soil. The aim of this study was to characterize water storage capacity in 9 Mediterranean shrub species, working with the whole plant and comparing results obtained by two methods, rainfall simulation and submersion method in laboratory conditions. (Author) 12 refs.

  12. Can shrubs help to reconstruct historical glacier retreats?

    International Nuclear Information System (INIS)

    Buras, Allan; Hallinger, Martin; Wilmking, Martin

    2012-01-01

    In the 21st century, most of the world’s glaciers are expected to retreat due to further global warming. The range of this predicted retreat varies widely as a result of uncertainties in climate and glacier models. To calibrate and validate glacier models, past records of glacier mass balance are necessary, which often only span several decades. Long-term reconstructions of glacier mass balance could increase the precision of glacier models by providing the required calibration data. Here we show the possibility of applying shrub growth increments as an on-site proxy for glacier summer mass balance, exemplified by Salix shrubs in Finse, Norway. We further discuss the challenges which this method needs to meet and address the high potential of shrub growth increments for reconstructing glacier summer mass balance in remote areas. (letter)

  13. Environmental Limits of Tall Shrubs in Alaska's Arctic National Parks.

    Science.gov (United States)

    Swanson, David K

    2015-01-01

    We sampled shrub canopy volume (height times area) and environmental factors (soil wetness, soil depth of thaw, soil pH, mean July air temperature, and typical date of spring snow loss) on 471 plots across five National Park Service units in northern Alaska. Our goal was to determine the environments where tall shrubs thrive and use this information to predict the location of future shrub expansion. The study area covers over 80,000 km2 and has mostly tundra vegetation. Large canopy volumes were uncommon, with volumes over 0.5 m3/m2 present on just 8% of plots. Shrub canopy volumes were highest where mean July temperatures were above 10.5°C and on weakly acid to neutral soils (pH of 6 to 7) with deep summer thaw (>80 cm) and good drainage. On many sites, flooding helped maintain favorable soil conditions for shrub growth. Canopy volumes were highest where the typical snow loss date was near 20 May; these represent sites that are neither strongly wind-scoured in the winter nor late to melt from deep snowdrifts. Individual species varied widely in the canopy volumes they attained and their response to the environmental factors. Betula sp. shrubs were the most common and quite tolerant of soil acidity, cold July temperatures, and shallow thaw depths, but they did not form high-volume canopies under these conditions. Alnus viridis formed the largest canopies and was tolerant of soil acidity down to about pH 5, but required more summer warmth (over 12°C) than the other species. The Salix species varied widely from S. pulchra, tolerant of wet and moderately acid soils, to S. alaxensis, requiring well-drained soils with near neutral pH. Nearly half of the land area in ARCN has mean July temperatures of 10.5 to 12.5°C, where 2°C of warming would bring temperatures into the range needed for all of the potential tall shrub species to form large canopies. However, limitations in the other environmental factors would probably prevent the formation of large shrub canopies

  14. Environmental Limits of Tall Shrubs in Alaska's Arctic National Parks.

    Directory of Open Access Journals (Sweden)

    David K Swanson

    Full Text Available We sampled shrub canopy volume (height times area and environmental factors (soil wetness, soil depth of thaw, soil pH, mean July air temperature, and typical date of spring snow loss on 471 plots across five National Park Service units in northern Alaska. Our goal was to determine the environments where tall shrubs thrive and use this information to predict the location of future shrub expansion. The study area covers over 80,000 km2 and has mostly tundra vegetation. Large canopy volumes were uncommon, with volumes over 0.5 m3/m2 present on just 8% of plots. Shrub canopy volumes were highest where mean July temperatures were above 10.5°C and on weakly acid to neutral soils (pH of 6 to 7 with deep summer thaw (>80 cm and good drainage. On many sites, flooding helped maintain favorable soil conditions for shrub growth. Canopy volumes were highest where the typical snow loss date was near 20 May; these represent sites that are neither strongly wind-scoured in the winter nor late to melt from deep snowdrifts. Individual species varied widely in the canopy volumes they attained and their response to the environmental factors. Betula sp. shrubs were the most common and quite tolerant of soil acidity, cold July temperatures, and shallow thaw depths, but they did not form high-volume canopies under these conditions. Alnus viridis formed the largest canopies and was tolerant of soil acidity down to about pH 5, but required more summer warmth (over 12°C than the other species. The Salix species varied widely from S. pulchra, tolerant of wet and moderately acid soils, to S. alaxensis, requiring well-drained soils with near neutral pH. Nearly half of the land area in ARCN has mean July temperatures of 10.5 to 12.5°C, where 2°C of warming would bring temperatures into the range needed for all of the potential tall shrub species to form large canopies. However, limitations in the other environmental factors would probably prevent the formation of large

  15. 76 FR 28079 - Notice of Intent To Repatriate Cultural Items: Arizona State Museum, University of Arizona...

    Science.gov (United States)

    2011-05-13

    ... Arizona State Museum, University of Arizona, Tucson, AZ, that meet the definitions of unassociated... 4 eagle feathers, 1 stone purifying bowl, 3 medicine man's baskets, 1 medicine basket lid, 4 medicine man's basket fragments, 1 animal bone, 2 carved animal effigies, 1 carved human effigy, 1 feather...

  16. COMPARISONS OF PESTICIDE LEVELS AND EXPOSURES IN NHEXAS ARIZONA AND ARIZONA-MEXICO BORDER POPULATIONS

    Science.gov (United States)

    The distributions of organophosphate (OP) insecticides chlorpyrifos and diazinon in exposure matrices such as indoor air, house dust, food, and water have been determined for 416 homes in the general Arizona population, and for 87 homes along the Arizona-Mexico border. The con...

  17. Territory and nest site selection patterns by Grasshopper Sparrows in southeastern Arizona

    Science.gov (United States)

    Ruth, Janet M.; Skagen, Susan K.

    2017-01-01

    Grassland bird populations are showing some of the greatest rates of decline of any North American birds, prompting measures to protect and improve important habitat. We assessed how vegetation structure and composition, habitat features often targeted for management, affected territory and nest site selection by Grasshopper Sparrows (Ammodramus savannarum ammolegus) in southeastern Arizona. To identify features important to males establishing territories, we compared vegetation characteristics of known territories and random samples on 2 sites over 5 years. We examined habitat selection patterns of females by comparing characteristics of nest sites with territories over 3 years. Males selected territories in areas of sparser vegetation structure and more tall shrubs (>2 m) than random plots on the site with low shrub densities. Males did not select territories based on the proportion of exotic grasses. Females generally located nest sites in areas with lower small shrub (1–2 m tall) densities than territories overall when possible and preferentially selected native grasses for nest construction. Whether habitat selection was apparent depended upon the range of vegetation structure that was available. We identified an upper threshold above which grass structure seemed to be too high and dense for Grasshopper Sparrows. Our results suggest that some management that reduces vegetative structure may benefit this species in desert grasslands at the nest and territory scale. However, we did not assess initial male habitat selection at a broader landscape scale where their selection patterns may be different and could be influenced by vegetation density and structure outside the range of values sampled in this study.

  18. Endemic Nephropathy Around the World.

    Science.gov (United States)

    Gifford, Fiona J; Gifford, Robert M; Eddleston, Michael; Dhaun, Neeraj

    2017-03-01

    There have been several global epidemics of chronic kidney disease of unknown etiology (CKD u ). Some, such as Itai-Itai disease in Japan and Balkan endemic nephropathy, have been explained, whereas the etiology of others remains unclear. In countries such as Sri Lanka, El Salvador, Nicaragua, and India, CKD u is a major public health problem and causes significant morbidity and mortality. Despite their geographical separation, however, there are striking similarities between these endemic nephropathies. Young male agricultural workers who perform strenuous labor in extreme conditions are the worst affected. Patients remain asymptomatic until end-stage renal failure. Biomarkers of tubular injury are raised, and kidney biopsy shows chronic interstitial nephritis with associated tubular atrophy. In many of these places access to dialysis and transplantation is limited, leaving few treatment options. In this review we briefly describe the major historic endemic nephropathies. We then summarize the epidemiology, clinical features, histology and clinical course of CKD u in Mesoamerica, Sri Lanka, India, Egypt, and Tunisia. We draw comparisons between the proposed etiologies and supporting research. Recognition of the similarities may reinforce the international drive to establish causality and to effect prevention.

  19. Endemic Nephropathy Around the World

    Directory of Open Access Journals (Sweden)

    Fiona J. Gifford

    2017-03-01

    Full Text Available There have been several global epidemics of chronic kidney disease of unknown etiology (CKDu. Some, such as Itai-Itai disease in Japan and Balkan endemic nephropathy, have been explained, whereas the etiology of others remains unclear. In countries such as Sri Lanka, El Salvador, Nicaragua, and India, CKDu is a major public health problem and causes significant morbidity and mortality. Despite their geographical separation, however, there are striking similarities between these endemic nephropathies. Young male agricultural workers who perform strenuous labor in extreme conditions are the worst affected. Patients remain asymptomatic until end-stage renal failure. Biomarkers of tubular injury are raised, and kidney biopsy shows chronic interstitial nephritis with associated tubular atrophy. In many of these places access to dialysis and transplantation is limited, leaving few treatment options. In this review we briefly describe the major historic endemic nephropathies. We then summarize the epidemiology, clinical features, histology and clinical course of CKDu in Mesoamerica, Sri Lanka, India, Egypt, and Tunisia. We draw comparisons between the proposed etiologies and supporting research. Recognition of the similarities may reinforce the international drive to establish causality and to effect prevention.

  20. The endemic medicinal plants of Northern Balochistan, Pakistan and their uses in traditional medicine.

    Science.gov (United States)

    Bibi, Tahira; Ahmad, Mushtaq; Mohammad Tareen, Niaz; Jabeen, Rukhsana; Sultana, Shazia; Zafar, Muhammad; Zain-ul-Abidin, Sheikh

    2015-09-15

    The highlands of Northern Balochistan are the hot spots of medicinal and endemic plant in Pakistan. These plants are still commonly used for medicinal purposes by local people in their daily lives. This study first documented the information about the medicinal uses of endemic species of Balochistan-province Pakistan. A survey was performed using open ended questionnaires, free listening and personal observations with 152 informants (54% female, 46% male). In addition, the use value (MUV), use report (UR), fidelity level (FL), frequency citation (FC), relative frequency citation (RFC), family importance value (FIV) of species were determined and the informant consensus factor (ICF) was calculated for the medicinal plants included in the study. A total of 24 endemic plants belonging to 19 genera and 14 families were used by the local inhabitants to treat 12 categories of various diseases. The most common families of endemic plant species as depicted by its number of species (6 species) and FIV (9.9) was Fabaceae as the dominant family. The endemic plant species comprised perennial herbs (30%), annual herbs (25%), shrubs (29%) and under shrubs (16% each), no endemic tree species was reported in the study area. The highest number of species were used in the treatment of gastrointestinal diseases (12 species). The main route of administration is oral injection (62%) while the most frequently used form of external administration of herbal medicine was paste (5.4%) and the most commonly applied methods of preparation are powder (48.2%). Highest use report were calculated for Allium baluchistanicum and Viola makranica, (8 UR each), and least use report were calculated for two species Heliotropium remotiflorum and Tetracme stocksii (1 UR for each). Use values of the recorded plant species have been calculated which showed a highest use value of (0.73) for A. baluchistanicum and (0.56) for Berberis baluchistanica while the lowest UVs were attained for T. stocksii (0

  1. Uptake of Radium by Grass and Shrubs Grown on Mineral Heaps: A Preliminary Study

    International Nuclear Information System (INIS)

    Laili, Z.; Omar, M.; Yusof, M.A. Wahab; Ibrahim, M.Z.

    2015-01-01

    A preliminary study of the uptake of 226 Ra and 228 Ra by grass and shrubs grown on mineral heaps was carried out. Activity concentrations of 226 Ra and 228 Ra in grass and shrubs were measured using gamma spectrometry. The result showed that grass and shrubs grown on mineral heaps contained elevated levels of radium compared to grass and shrubs grown on normal soils. Thus, these plants might be used for phytoremediation of radium contaminated soil. (author)

  2. GROWTH-RATES OF SHRUBS ON DIFFERENT SOILS IN TANZANIA

    NARCIS (Netherlands)

    PRINS, HHT; VANDERJEUGD, HP

    1992-01-01

    Because little is known of growth rates of shrubs in East Africa, the growth rates of Acalypha fructicosa, Gardenia jovis-tonantis, Justicia cordata, Maerua triphylla, and Ocimum suave were measured in Lake Manyara National Park, northern Tanzania. Branch diameter increments and branch length

  3. Growth rates of shrubs on different soils in Tanzania.

    NARCIS (Netherlands)

    Prins, H.H.T.; Jeugd, van der H.P.

    1992-01-01

    Because little is known of growth rates of shrubs in East Africa, the growth rates of Acalypha fructicosa, Gardenia jovis-tonantis, Justicia cordata, Maerua triphylla, and Ocimum suave were measured in Lake Manyara National Park, northern Tanzania. Branch diameter increments and branch length

  4. Experimental and numerical modeling of shrub crown fire initiation

    Science.gov (United States)

    Watcharapong Tachajapong; Jesse Lozano; Shakar Mahalingam; Xiangyang Zhou; David Weise

    2009-01-01

    The transition of fire from dry surface fuels to wet shrub crown fuels was studied using laboratory experiments and a simple physical model to gain a better understanding of the transition process. In the experiments, we investigated the effects of varying vertical distances between surface and crown fuels (crown base height), and of the wind speed on crown fire...

  5. Drought damage to bushveld trees and large shrubs | JJP | African ...

    African Journals Online (AJOL)

    An intensive survey was carried out in Sweet Bushveld (savanna) to study drought damage to the trees and large shrubs in a Combretum apiculatum community. In general, the severity of damage was less than was expected and its pattern differed markedly between the 21 different species encountered. Keywords: ...

  6. Seeds of Puerto Rican Trees and Shrubs: Second Installment

    Science.gov (United States)

    John K. Francis; Alberto Rodríguez

    1993-01-01

    Seed weights and germination information were obtained for 119 native Puerto Rican and naturalized exotic trees and shrubs. Fruit was collected from 34 of these species, and the weights were recorded. The data are presented in tables that list the species alphabetically by scientific names.

  7. Use and availability of tree and shrub resources on Maasai ...

    African Journals Online (AJOL)

    Twenty-four tree and shrub species were utilised for four main purposes: medicinal, fencing, firewood and shelter. These uses were mainly confined to four key species: Acacia mellifera, Acacia xanthophloea , Acacia tortilisand Balanites glabra. Ethno-medicine was the most common use and required smaller quantities of ...

  8. Recent emissions research in southwestern shrub and grassland fuels

    Science.gov (United States)

    David R. Weise; Wayne Miller; David R. Cocker; Heejung Jung; Seyedehsan Hosseini; Marko Princevac; Robert J. Yokelson; Ian Burling; Sheryl Akagi; Shawn Urbanski; WeiMin Hao

    2015-01-01

    While it is currently challenging to use prescribed burning in chaparral and other southwestern shrub fuel types due to many constraints, any such activities require smoke management planning. Information on fuels and emissions from chaparral were limited and based on older sampling systems. The DoD SERDP program funded a project to measure fuels and smoke emissions in...

  9. The Invasive Shrub, Buddleja davidii (Butterfl y Bush)

    Science.gov (United States)

    Buddleja davidii Franchet (Synonym. Buddleia davidii; common name Butterfly bush) is a perennial, semi-deciduous shrub or small multi-stemmed tree that is resident in gardens and disturbed areas in temperate locations worldwide. Since its introduction to the United Kingdom from c...

  10. Siliceous Shrubs in Yellowstone's Hot Springs: Implications for Exobiological Investigations

    Science.gov (United States)

    Guidry, S. A.; Chafetz, H. S.

    2003-01-01

    Potential relict hot springs have been identified on Mars and, using the Earth as an analog, Martian hot springs are postulated to be an optimal locality for recognizing preserved evidence of extraterrestrial life. Distinctive organic and inorganic biomarkers are necessary to recognize preserved evidence of life in terrestrial and extraterrestrial hot spring accumulations. Hot springs in Yellowstone National Park, Wyoming, U.S.A., contain a wealth of information about primitive microbial life and associated biosignatures that may be useful for future exobiological investigations. Numerous siliceous hot springs in Yellowstone contain abundant, centimeter-scale, spinose precipitates of opaline silica (opal-A). Although areally extensive in siliceous hot spring discharge channel facies, these spinose forms have largely escaped attention. These precipitates referred to as shrubs, consist of porous aggregates of spinose opaline silica that superficially resemble miniature woody plants, i.e., the term shrubs. Shrubs in carbonate precipitating systems have received considerable attention, and represent naturally occurring biotically induced precipitates. As such, shrubs have great potential as hot spring environmental indicators and, more importantly, proxies for pre-existing microbial life.

  11. Plant Identification Characteristics for Deciduous Trees & Shrubs. Lesson Plans.

    Science.gov (United States)

    Burkholder, Kathy

    This manual contains a group of lesson plans designed for use with a slide series (not included here). Its purpose is to introduce students to the basic concepts and terminology used in the identification of deciduous trees and shrubs. The manual is composed of 12 lesson plans. The first lesson is an introduction to plant identification. The…

  12. Environmental indices for common Michigan trees and shrubs.

    Science.gov (United States)

    Gary J. Brand

    1985-01-01

    Plants are indicators of environmental factors like moisture, nutrients, heat, and light. Semi-quantitative indices for these four factors were developed for 90 Michigan trees and shrubs. The indices and a tally of species present provide a simple evaluation of the environment of a forest stand and a useful management aid.

  13. Ecology and utilization of desert shrub rangelands in Iraq

    NARCIS (Netherlands)

    Thalen, Derk Catharinus Peter

    1979-01-01

    When grazing is the accepted land use, vegetation is the key resource. The present study deals with the desert shrub rangelands of lraq, which contain the major characteristics of such an area, having been under grazing for many centuries. Emphasis is given to the ecology and utilization of the

  14. Molecular detection of airborne Coccidioides in Tucson, Arizona

    Science.gov (United States)

    Chow, Nancy A.; Griffin, Dale W.; Barker, Bridget M.; Loparev, Vladimir N.; Litvintseva, Anastasia P.

    2016-01-01

    Environmental surveillance of the soil-dwelling fungus Coccidioides is essential for the prevention of Valley fever, a disease primarily caused by inhalation of the arthroconidia. Methods for collecting and detectingCoccidioides in soil samples are currently in use by several laboratories; however, a method utilizing current air sampling technologies has not been formally demonstrated for the capture of airborne arthroconidia. In this study, we collected air/dust samples at two sites (Site A and Site B) in the endemic region of Tucson, Arizona, and tested a variety of air samplers and membrane matrices. We then employed a single-tube nested qPCR assay for molecular detection. At both sites, numerous soil samples (n = 10 at Site A and n = 24 at Site B) were collected and Coccidioides was detected in two samples (20%) at Site A and in eight samples (33%) at Site B. Of the 25 air/dust samples collected at both sites using five different air sampling methods, we detected Coccidioides in three samples from site B. All three samples were collected using a high-volume sampler with glass-fiber filters. In this report, we describe these methods and propose the use of these air sampling and molecular detection strategies for environmental surveillance of Coccidioides.

  15. The impact of Arizona Highways Magazine's facebook page.

    Science.gov (United States)

    2014-02-01

    This project examined the relationship between use of the Arizona Highways magazine (AHM) Facebook Page and the decision to : travel to or within Arizona. Key purposes were to: (1) provide a thorough understanding of AHM Facebook Page users, includin...

  16. 21 CFR 866.3035 - Arizona spp. serological reagents.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3035 Arizona spp... antisera and antigens used to identify Arizona spp. in cultured isolates derived from clinical specimens...

  17. tree and shrub species integration in the crop-livestock farming ...

    African Journals Online (AJOL)

    Prof. Adipala Ekwamu

    cash for investment in the required activities, easy land certification and market opportunity for tree and shrub products. The tree and shrub .... for its consistency, logical flow, coding and length were amended. .... TABLE 2. List of shrub species identified in the watershed of highlands of central Ethiopia. Scientific name.

  18. Assessing effect of rainfall on rate of alien shrub expansion in a southern African savanna

    NARCIS (Netherlands)

    Masocha, Mhosisi; Dube, Timothy; Skidmore, A.K.; Holmgren, Milena; Prins, Herbert

    2017-01-01

    Understanding the environmental factors governing the spread of alien shrubs is crucial for conserving biodiversity. In the semi-arid savannas of Africa, alien shrub invasion often occurs simultaneously with native shrub encroachment but climate-dependent differences in encroachments of native and

  19. Shrubs as ecosystem engineers across an environmental gradient: effects on species richness and exotic plant invasion.

    Science.gov (United States)

    Kleinhesselink, Andrew R; Magnoli, Susan M; Cushman, J Hall

    2014-08-01

    Ecosystem-engineering plants modify the physical environment and can increase species diversity and exotic species invasion. At the individual level, the effects of ecosystem engineers on other plants often become more positive in stressful environments. In this study, we investigated whether the community-level effects of ecosystem engineers also become stronger in more stressful environments. Using comparative and experimental approaches, we assessed the ability of a native shrub (Ericameria ericoides) to act as an ecosystem engineer across a stress gradient in a coastal dune in northern California, USA. We found increased coarse organic matter and lower wind speeds within shrub patches. Growth of a dominant invasive grass (Bromus diandrus) was facilitated both by aboveground shrub biomass and by growing in soil taken from shrub patches. Experimental removal of shrubs negatively affected species most associated with shrubs and positively affected species most often found outside of shrubs. Counter to the stress-gradient hypothesis, the effects of shrubs on the physical environment and individual plant growth did not increase across the established stress gradient at this site. At the community level, shrub patches increased beta diversity, and contained greater rarified richness and exotic plant cover than shrub-free patches. Shrub effects on rarified richness increased with environmental stress, but effects on exotic cover and beta diversity did not. Our study provides evidence for the community-level effects of shrubs as ecosystem engineers in this system, but shows that these effects do not necessarily become stronger in more stressful environments.

  20. Spatial patterns of grasses and shrubs in an arid grassland environment

    Science.gov (United States)

    In the Chihuahuan Desert of Mexico and New Mexico, shrub invasion is a common problem, and once-abundant grassland ecosystems are being replaced by shrub-dominated habitat. The spatial arrangement of grasses and shrubs in these arid grasslands can provide better insight into community dynamics and c...

  1. March 2014 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2014-04-01

    Full Text Available No abstract available. Article truncated after 150 words. The March 2014 Arizona Thoracic Society meeting was a special meeting. In conjunction with the Valley Fever Center for Excellence and the Arizona Respiratory Center the Eighteenth Annual Farness Lecture was held in the Sonntag Pavilion at St. Joseph's Hospital at 6 PM on Friday, April 4, 2014. The guest speaker was Antonio "Tony" Catanzaro, MD from the University of California San Diego and current president of the Cocci Study Group. There were 57 in attendance representing the pulmonary, critical care, sleep, and infectious disease communities. After opening remarks by Arizona Thoracic Society president, Lewis Wesselius (a former fellow under Dr. Catanzaro at UCSD, John Galgiani, director of the Valley Fever Center for Excellence, gave a brief history of the Farness lecture before introducing Dr. Catanzaro. The lecture is named for Orin J. Farness, a Tucson physician, who was the first to report culture positive coccidioidomycosis (cocci or Valley Fever. ...

  2. 30 CFR 903.700 - Arizona Federal program.

    Science.gov (United States)

    2010-07-01

    ... Resources has jurisdiction over the mining of minerals, and oil and gas under Title 27 of the Arizona....700 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PROGRAMS FOR THE CONDUCT OF SURFACE MINING OPERATIONS WITHIN EACH STATE ARIZONA § 903.700 Arizona Federal...

  3. 75 FR 18145 - Eastern Arizona Counties Resource Advisory Committee

    Science.gov (United States)

    2010-04-09

    ... DEPARTMENT OF AGRICULTURE Forest Service Eastern Arizona Counties Resource Advisory Committee AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Eastern Arizona Counties Resource... Rivera, Coordinator, Eastern Arizona Counties Resource Advisory Committee, c/o Forest Service, USDA, P.O...

  4. Energy Fuels Nuclear, Inc. Arizona Strip Operations

    International Nuclear Information System (INIS)

    Pool, T.C.

    1993-01-01

    Founded in 1975 by uranium pioneer, Robert W. Adams, Energy Fuels Nuclear, Inc. (EFNI) emerged as the largest US uranium mining company by the mid-1980s. Confronting the challenges of declining uranium market prices and the development of high-grade ore bodies in Australia and Canada, EFNI aggressively pursued exploration and development of breccia-pipe ore bodies in Northwestern Arizona. As a result, EFNI's production for the Arizona Strip of 18.9 million pounds U 3 O 8 over the period 1980 through 1991, maintained the company's status as a leading US uranium producer

  5. Lower Colorado River GRP Dams and Water Retention Structures, Arizona, 2012, Arizona Department of Environmental Quality

    Data.gov (United States)

    U.S. Environmental Protection Agency — Location of dams and water retention structures as compiled from multiple sources by the Arizona Department of Environmental Quality (ADEQ). The data are "sensitive"...

  6. The effect of polyethylene glycol on intake of Mediterranean shrubs by sheep and goats.

    Science.gov (United States)

    Rogosic, J; Pfister, J A; Provenza, F D; Pavlicevic, J

    2008-12-01

    Poor nutritional quality and increased content of secondary compounds can reduce consumption of Mediterranean shrubs by herbivores. In 2 sequential trials, we examined the effect of polyethylene glycol (PEG) and number of shrub species offered on daily intake of Mediterranean shrubs by 12 sheep and 12 goats. The PEG (25 g) was fed to experimental animals with barley. In trial 1 (6 shrubs), goats ate more (P = 0.0008) daily total shrub biomass than did sheep (60.7 vs. 45.9 +/- 2.6 g/kg of BW). There was a trend (P = 0.08) toward a positive PEG effect on total shrub intake, with PEG-supplemented animals consuming more total shrubs than controls (56.7 vs. 50.0 +/- 2.6 g/kg of BW). Trial 2 (using 3 shrubs) was a continuation of trial 1, except that animals were given less barley and treatment animals were given more PEG (50 g). Both sheep and goats showed a numerical decrease in total shrub intake from trial 1 to trial 2. Sheep receiving PEG ate more (P = 0.002) total shrubs than did controls, but no PEG effect was found for goats. Thus, PEG had a greater influence on sheep than goats when only 3 shrubs were offered, a result that may be related to the fact that fewer shrubs with complementary secondary compounds were offered and that goats appear to have a greater ability to consume and detoxify secondary compounds from Mediterranean shrubs. Overall, as the number and diversity of shrubs offered increased, supplemental PEG had less effect on increasing intake for both goats and sheep.

  7. Role of species diversity and secondary compound complementarity on diet selection of Mediterranean shrubs by goats.

    Science.gov (United States)

    Rogosic, Jozo; Estell, Richard E; Skobic, Dragan; Martinovic, Anita; Maric, Stanislava

    2006-06-01

    Goats foraging on Mediterranean shrubs containing secondary compounds (toxins) may consume a variety of shrubs that contain different phytotoxins, thereby increasing shrub intake and avoiding toxicosis. We conducted eight experiments to examine whether goats offered different mixtures of shrubs containing different phytotoxins (tannins and saponins) would consume more shrub biomass than goats offered one shrub a single phytotoxin (tannin or saponin). In the first three experiments, goats fed a mixture of three tannin-rich shrubs (Quercus ilex, Arbutus unedo, and Pistacia lentiscus) ate more foliage than goats offered only one shrub (23.2 vs. 10.7 g/kg BW; 25.2 vs. 13.4 g/kg BW, and 27.9 vs. 7.9 g/kg BW), regardless of tannin concentration in individual shrub species. Goats also consumed more foliage when offered the same three tannin-rich shrubs than when offered the saponin-rich shrub Hedera helix (25.4 vs. 8.0 g/kg BW). However, goats offered a mixture of the same three tannin-rich shrubs consumed less foliage than goats offered a mixture of two shrubs containing tannins and saponins: Quercus and Hedera (21.6 vs. 27.1 g/kg BW), Arbutus and Hedera (21.8 vs. 27.1 g/kg BW), and Pistacia and Hedera (19.7 vs. 22.0 g/kg BW). Comparison of intake of shrubs containing only tannins or saponins to intake of shrubs containing both tannins and saponins indicated that goats consumed more total biomass when fed with shrubs with both classes of compounds than with either tannins or saponins alone. Our results suggest that goats can increase intake of Mediterranean shrubs high in secondary compounds by selecting those with different classes of phytotoxins. Simultaneous ingestion of shrubs containing tannins and saponins may promote chemical interactions that inhibit toxic effects of these phytotoxins in the intestinal tract. In addition to complementary interactions between tannins and saponins, biological diversity within Mediterranean maquis vegetation also plays a positive

  8. Generating new varieties of shrubs for landscapes in Malaysia

    International Nuclear Information System (INIS)

    Zaiton Ahmad; Affrida Abu Hassan; Shuhaimi Shamsudin; Norimah Yusof; Shakinah Salleh

    2012-01-01

    This project which was funded by National Landscape Department was aimed at generating new varieties of shrubs suitable for landscapes in Malaysia. Three species of shrubs commonly used in Malaysian landscapes (hibiscus, canna and turnera) were selected for generating new varieties through mutagenesis techniques using gamma rays and ion beams. The main objective was to produce new varieties with desired characters, such as longer bloom period, unique and prominent petal colors and larger flower size. Through this project, several potential mutants have been identified such as turnera with longer bloom period, canna with new flower colors and hibiscus with different flower form. These mutants are currently undergoing field screening at Serdang to analyze their genetic stability, and will be registered as new varieties with Department of Agriculture before being transferred to end-users. (author)

  9. Shrub Abundance Mapping in Arctic Tundra with Misr

    Science.gov (United States)

    Duchesne, R.; Chopping, M. J.; Wang, Z.; Schaaf, C.; Tape, K. D.

    2013-12-01

    Over the last 60 years an increase in shrub abundance has been observed in the Arctic tundra in connection with a rapid surface warming trend. Rapid shrub expansion may have consequences in terms of ecosystem structure and function, albedo, and feedbacks to climate; however, its rate is not yet known. The goal of this research effort is thus to map large scale changes in Arctic tundra vegetation by exploiting the structural signal in moderate resolution satellite remote sensing images from NASA's Multiangle Imaging SpectroRadiometer (MISR), mapped onto a 250m Albers Conic Equal Area grid. We present here large area shrub mapping supported by reference data collated using extensive field inventory data and high resolution panchromatic imagery. MISR Level 1B2 Terrain radiance scenes from the Terra satellite from 15 June-31 July, 2000 - 2010 were converted to surface bidirectional reflectance factors (BRF) using MISR Toolkit routines and the MISR 1 km LAND product BRFs. The red band data in all available cameras were used to invert the RossThick-LiSparse-Reciprocal BRDF model to retrieve kernel weights, model-fitting RMSE, and Weights of Determination. The reference database was constructed using aerial survey, three field campaigns (field inventory for shrub count, cover, mean radius and height), and high resolution imagery. Tall shrub number, mean crown radius, cover, and mean height estimates were obtained from QuickBird and GeoEye panchromatic image chips using the CANAPI algorithm, and calibrated using field-based estimates, thus extending the database to over eight hundred locations. Tall shrub fractional cover maps for the North Slope of Alaska were constructed using the bootstrap forest machine learning algorithm that exploits the surface information provided by MISR. The reference database was divided into two datasets for training and validation. The model derived used a set of 19 independent variables(the three kernel weights, ratios and interaction terms

  10. Arizona Public Library Statistics, 2000-2001.

    Science.gov (United States)

    Elliott, Jan, Comp.

    These statistics were compiled from information supplied by Arizona's public libraries. The document is divided according to the following county groups: Apache, Cochise; Coconino, Gila; Graham, Greenlee, La Paz; Maricopa; Mohave, Navajo; Pima, Pinal; Santa Cruz, Yavapai; and Yuma. Statistics are presented on the following: general information;…

  11. Arizona Public Library Statistics. 1994-1995.

    Science.gov (United States)

    Arizona State Dept. of Library and Archives, Phoenix.

    The statistics in this document were provided by Arizona public libraries for 1994-95. The counties are grouped as follows: Apache, Cochise,and Coconino; Gila, Graham, Greenlee, and La Paz; Maricopa and Mohave; Navajo, Pima, and Pinal; and Santa Cruz, Yavapai, and Yuma. The following data is presented in table form for each of the five groups: (1)…

  12. Arizona Public Library Statistics, 1999-2000.

    Science.gov (United States)

    Arizona State Dept. of Library, Archives and Public Records, Phoenix.

    These statistics were compiled from information supplied by Arizona's public libraries. The document is divided according to the following county groups: Apache, Cochise; Coconino, Gila; Graham, Greenlee, La Paz; Maricopa; Mohave, Navajo; Pima, Pinal; Santa Cruz, Yavapai; Yuma. Statistics are presented on the following: general information;…

  13. Arizona Public Library Statistics, 1995-1996.

    Science.gov (United States)

    Arizona State Dept. of Library, Archives and Public Records, Phoenix.

    The statistics in this document were provided by Arizona public libraries for 1995-96. The counties are grouped as follows: Apache, Cochise, and Coconino; Gila, Graham, Greenlee, and La Paz; Maricopa and Mohave; Navajo, Pima, and Pinal; and Santa Cruz, Yavapai, and Yuma. The following data is presented in table form for each of the five groups:…

  14. Marginalizing TESOL: Preservice Teacher Training in Arizona

    Science.gov (United States)

    Diniz de Figueiredo, Eduardo H.; Hammill, Matthew J.; Fredricks, Daisy E.

    2011-01-01

    This pilot study investigated the attitudes of preservice teachers at a major university in Arizona concerning the Structured English Immersion (SEI) program that is now being used with English language learners (ELLs). Using a survey, we examined how preservice teachers feel about potentially working with ELLs in this SEI context. We focused on…

  15. Arizona's Forgotten Children: Promises To Keep.

    Science.gov (United States)

    Children's Action Alliance, Phoenix, AZ.

    This report provides an Arizona perspective on the implications and effects of homelessness on children and youth, whether they live with their families or on their own. Statistics on homeless families are provided, and issues affecting homeless families are discussed. These issues involve shelters, child care, education, and health. Issues that…

  16. Turnover of Public School Superintendents in Arizona

    Science.gov (United States)

    Meyer, Joyce Ntsoaki

    2013-01-01

    This study used a descriptive qualitative design utilizing a phenomenological approach to determine and examine the reasons behind the voluntary or involuntary turnover of Arizona school superintendents. Open-ended questions were used to interview five superintendents who had left their districts between 2008 and 2013 about their perceptions on…

  17. Coccidiodomycosis in Arizona 2007-2008

    Centers for Disease Control (CDC) Podcasts

    2010-10-13

    This podcast looks at the impact of Coccidioidomycosis, or Valley Fever, in Arizona in 2007 and early 2008. CDC epidemiologist Dr. Tom Chiller discusses what researchers learned about this fungal disease.  Created: 10/13/2010 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 10/27/2010.

  18. 50 CFR 32.22 - Arizona.

    Science.gov (United States)

    2010-10-01

    ... of the State quail season. C. Big Game Hunting. We allow hunting of desert bighorn sheep in Arizona... the refuge from June 1 through August 19. C. Big Game Hunting. We allow hunting of mule and white... regulations subject to the following conditions: 1. You may only hunt feral hog during big game seasons. Each...

  19. Increased spring freezing vulnerability for alpine shrubs under early snowmelt.

    Science.gov (United States)

    Wheeler, J A; Hoch, G; Cortés, A J; Sedlacek, J; Wipf, S; Rixen, C

    2014-05-01

    Alpine dwarf shrub communities are phenologically linked with snowmelt timing, so early spring exposure may increase risk of freezing damage during early development, and consequently reduce seasonal growth. We examined whether environmental factors (duration of snow cover, elevation) influenced size and the vulnerability of shrubs to spring freezing along elevational gradients and snow microhabitats by modelling the past frequency of spring freezing events. We sampled biomass and measured the size of Salix herbacea, Vaccinium myrtillus, Vaccinium uliginosum and Loiseleuria procumbens in late spring. Leaves were exposed to freezing temperatures to determine the temperature at which 50% of specimens are killed for each species and sampling site. By linking site snowmelt and temperatures to long-term climate measurements, we extrapolated the frequency of spring freezing events at each elevation, snow microhabitat and per species over 37 years. Snowmelt timing was significantly driven by microhabitat effects, but was independent of elevation. Shrub growth was neither enhanced nor reduced by earlier snowmelt, but decreased with elevation. Freezing resistance was strongly species dependent, and did not differ along the elevation or snowmelt gradient. Microclimate extrapolation suggested that potentially lethal freezing events (in May and June) occurred for three of the four species examined. Freezing events never occurred on late snow beds, and increased in frequency with earlier snowmelt and higher elevation. Extrapolated freezing events showed a slight, non-significant increase over the 37-year record. We suggest that earlier snowmelt does not enhance growth in four dominant alpine shrubs, but increases the risk of lethal spring freezing exposure for less freezing-resistant species.

  20. Fire tolerance of a resprouting Artemisia (Asteraceae) shrub

    Science.gov (United States)

    Winter, S.L.; Fuhlendorf, S.D.; Goad, C.L.; Davis, C.A.; Hickman, K.R.; Leslie, David M.

    2011-01-01

    In North America, most Artemisia (Asteraceae) shrub species lack the ability to resprout after disturbances that remove aboveground biomass. We studied the response of one of the few resprouting Artemisia shrubs, Artemisia filifolia (sand sagebrush), to the effects of prescribed fires. We collected data on A. filifolia density and structural characteristics (height, canopy area, and canopy volume) in an A. filifolia shrubland in the southern Great Plains of North America. Our study sites included areas that had not been treated with prescribed fire, areas that had been treated with only one prescribed fire within the previous 5 years, and areas that had been treated with two prescribed fires within the previous 10 years. Our data were collected at time periods ranging from 1/2 to 5 years after the prescribed fires. Density of A. filifolia was not affected by one or two fires. Structural characteristics, although initially altered by prescribed fire, recovered to levels characteristic of unburned areas in 3-4 years after those fires. In contrast to most non-sprouting North American Artemisia shrub species, our research suggested that the resprouting A. filifolia is highly tolerant to the effects of fire. ?? 2011 Springer Science+Business Media B.V.

  1. Soil microbial diversity in the vicinity of desert shrubs.

    Science.gov (United States)

    Saul-Tcherkas, Vered; Unc, Adrian; Steinberger, Yosef

    2013-04-01

    Water and nutrient availability are the major limiting factors of biological activity in arid and semiarid ecosystems. Therefore, perennial plants have developed different ecophysiological adaptations to cope with harsh conditions. The chemical profile of the root exudates varies among plant species and this can induce variability in associated microbial populations. We examined the influence of two shrubs species, Artemisia sieberi and Noaea mucronata, on soil microbial diversity. Soil samples were collected monthly, from December 2006 to November 2007, near canopies of both shrubs (0-10-cm depth). Samples were used for abiotic tests and determination of soil bacterial diversity. No significant differences were found in the abiotic variables (soil moisture, total organic matter, and total soluble nitrogen (TSN)) between soil samples collected from under the two shrubs during the study period. No obvious differences in the Shannon-Weaver index, evenness values, or total phylogenetic distances were found for the soil microbial communities. However, detailed denaturing gradient gel electrophoresis (DGGE) clustering as well as taxonomic diversity analyses indicated clear shifts in the soil microbial community composition. These shifts were governed by seasonal variability in water availability and, significantly, by plant species type.

  2. The Influence of an Invasive Shrub, Buddleja Davidii on a Native Shrub, Griselinia Littoralis Transplanted into a New Zealand Floodplain Chronosequence

    Science.gov (United States)

    Griselinia littoralis, a native New Zealand shrub, was planted into a chronosequence (0 to 8 yrs since flooding) dominated by the non-indigenous shrub, Buddleja davidii in three New Zealand floodplains to determine to what extent facilitation and competitive inhibition may influe...

  3. Independent Effects of Invasive Shrubs and Deer Herbivory on Plant Community Dynamics

    Directory of Open Access Journals (Sweden)

    Jeffrey S. Ward

    2016-12-01

    Full Text Available Both invasive species and deer herbivory are recognized as locally important drivers of plant community dynamics. However, few studies have examined whether their effects are synergistic, additive, or antagonistic. At three study areas in southern New England, we examined the interaction of white-tailed deer (Odocoileus virginianus Zimmermann herbivory and three levels of invasive shrub control over seven growing seasons on the dynamics of nine herbaceous and shrub guilds. Although evidence of synergistic interactions was minimal, the separate effects of invasive shrub control and deer herbivory on plant community composition and dynamics were profound. Plant communities remained relatively unchanged where invasive shrubs were not treated, regardless if deer herbivory was excluded or not. With increasing intensity of invasive shrub control, native shrubs and forbs became more dominant where deer herbivory was excluded, and native graminoids became progressively more dominant where deer herbivory remained severe. While deer exclusion and intensive invasive shrub control increased native shrubs and forbs, it also increased invasive vines. Restoring native plant communities in areas with both established invasive shrub thickets and severe deer browsing will require an integrated management plan to eliminate recalcitrant invasive shrubs, reduce deer browsing intensity, and quickly treat other opportunistic invasive species.

  4. Spatio-temporal patterns of ptarmigan occupancy relative to shrub cover in the Arctic

    Science.gov (United States)

    Schmutz, Joel A.

    2014-01-01

    Rock and willow ptarmigan are abundant herbivores that require shrub habitats in arctic and alpine areas. Shrub expansion is likely to increase winter habitat availability for ptarmigan, which in turn influence shrub architecture and growth through browsing. Despite their ecological role in the Arctic, the distribution and movement patterns of ptarmigan are not well known, particularly in northern Alaska where shrub expansion is occurring. We used multi-season occupancy models to test whether ptarmigan occupancy varied within and among years, and the degree to which colonization and extinction probabilities were related to shrub cover and latitude. Aerial surveys were conducted from March to May in 2011 and April to May 2012 in a 21,230 km2 area in northeastern Alaska. In areas with at least 30 % shrub cover, the probability of colonization by ptarmigan was >0.90, indicating that moderate to extensive patches of shrubs (typically associated with riparian areas) had a high probability of becoming occupied by ptarmigan. Occupancy increased throughout the spring in both years, providing evidence that ptarmigan migrated from southern wintering areas to breeding areas north of the Brooks Range. Occupancy was higher in the moderate snow year than the high snow year, and this was likely due to higher shrub cover in the moderate snow year. Ptarmigan distribution and migration in the Arctic are linked to expanding shrub communities on a wide geographic scale, and these relationships may be shaping ptarmigan population dynamics, as well as rates and patterns of shrub expansion.

  5. SUPPLEMENTAL ACTIVATED CHARCOAL AND ENERGY INCREASE INTAKE OF MEDITERRANEAN SHRUBS BY SHEEP AND GOATS

    Directory of Open Access Journals (Sweden)

    Jozo Rogošić

    2008-07-01

    Full Text Available Utilization of the Mediterranean shrubby vegetation is often limited by secondary compounds, such as terpenes, which at too high concentrations can adversely affect forage intake and animal health. Ingesting compounds such as activated charcoal and energy can ameliorate the negative effects of secondary compounds and enable animals to eat more shrubs. Thus, our objectives were to determine if supplemental charcoal, energy and numbers of shrub species offered influenced intake of shrubs by sheep and goats. We conducted three experiments each with 12 lambs and 12 kids (6 activated charcoal vs. 6 controls. In the first experiment, we initially offered three shrubs (Juniperus phoenicea, Helichrysum italicum and Juniperus oxicedrus, then in the second one, two shrubs (Juniperus phoenicea and Helichrysum italicum, and finally one shrub (Juniperus phoenicea in the third experiment. In all three experiments (Exp. 1, P<0.001; Exp. 2, P < 0.0003 and Exp. 3, P < 0.03, supplemental charcoal and energy had a positive effect on total shrub intake for both lambs and kids. Kids ate more shrubs than lambs did in all three experiments (P<0.01. Regardless of experiment, both species of animals showed a numerical decrease in total shrub intake, with or without supplemental charcoal and energy, as the number of shrub species on offer decreased. Our findings support the hypothesis that biochemical diversity plays an important role in diet selection, thus enabling animals to better meet their nutritional needs and avoid toxicity.

  6. [Quality level assessment of lowly efficient Tamarix chinensis secondary shrubs in Laizhou Bay of Yellow River Delta].

    Science.gov (United States)

    Xia, Jiang-Bao; Liu, Yu-Ting; Zhu, Jin-Fang; Xu, Jing-Wei; Lu, Zhao-Hua; Liu, Jing-Tao; Liu, Qing

    2013-06-01

    Taking the Tamarix chinensis secondary shrubs in Laizhou Bay of Yellow River Delta as test objects, and by using synthetic factor method, this paper studied the main factors causing the lowly efficiency of T. chinensis secondary shrubs as well as the main parameters for the classification of lowly efficient T. chinensis secondary shrubs. A total of 24 indices including shrubs growth and soil physical and chemical properties were selected to determine the main affecting factors and parameters in evaluating and classifying the lowly efficient shrubs. There were no obvious correlations between the indices reflecting the shrubs growth and soil quality, and thus, only using shrub growth index to reflect the lowly efficiency level of T. chinensis was not enough, and it would be necessary to combine with soil quality factors to make a comprehensive evaluation. The principal factors reflecting the quality level of lowly efficient T. chinensis shrubs included soil salt content and moisture content, stand age, single tree's aboveground stem, leaf biomass, and basal diameter, followed by soil density, porosity, and soil nutrient status. The lowly efficient T. chinensis shrubs in the Bay could be classified into five types, namely, shrub with growth potential, slightly low quality shrub, moderately lowly efficient shrub, moderately low quality and lowly efficient shrub, and seriously low quality and lowly efficient shrub. The main features, low efficiency causes, and management measures of these shrubs were discussed based on the mean cluster value.

  7. Delimiting areas of endemism through kernel interpolation.

    Science.gov (United States)

    Oliveira, Ubirajara; Brescovit, Antonio D; Santos, Adalberto J

    2015-01-01

    We propose a new approach for identification of areas of endemism, the Geographical Interpolation of Endemism (GIE), based on kernel spatial interpolation. This method differs from others in being independent of grid cells. This new approach is based on estimating the overlap between the distribution of species through a kernel interpolation of centroids of species distribution and areas of influence defined from the distance between the centroid and the farthest point of occurrence of each species. We used this method to delimit areas of endemism of spiders from Brazil. To assess the effectiveness of GIE, we analyzed the same data using Parsimony Analysis of Endemism and NDM and compared the areas identified through each method. The analyses using GIE identified 101 areas of endemism of spiders in Brazil GIE demonstrated to be effective in identifying areas of endemism in multiple scales, with fuzzy edges and supported by more synendemic species than in the other methods. The areas of endemism identified with GIE were generally congruent with those identified for other taxonomic groups, suggesting that common processes can be responsible for the origin and maintenance of these biogeographic units.

  8. Delimiting areas of endemism through kernel interpolation.

    Directory of Open Access Journals (Sweden)

    Ubirajara Oliveira

    Full Text Available We propose a new approach for identification of areas of endemism, the Geographical Interpolation of Endemism (GIE, based on kernel spatial interpolation. This method differs from others in being independent of grid cells. This new approach is based on estimating the overlap between the distribution of species through a kernel interpolation of centroids of species distribution and areas of influence defined from the distance between the centroid and the farthest point of occurrence of each species. We used this method to delimit areas of endemism of spiders from Brazil. To assess the effectiveness of GIE, we analyzed the same data using Parsimony Analysis of Endemism and NDM and compared the areas identified through each method. The analyses using GIE identified 101 areas of endemism of spiders in Brazil GIE demonstrated to be effective in identifying areas of endemism in multiple scales, with fuzzy edges and supported by more synendemic species than in the other methods. The areas of endemism identified with GIE were generally congruent with those identified for other taxonomic groups, suggesting that common processes can be responsible for the origin and maintenance of these biogeographic units.

  9. Environmental Monitoring of Endemic Cholera

    Science.gov (United States)

    ElNemr, W.; Jutla, A. S.; Constantin de Magny, G.; Hasan, N. A.; Islam, M.; Sack, R.; Huq, A.; Hashem, F.; Colwell, R.

    2012-12-01

    Cholera remains a major public health threat. Since Vibrio cholerae, the causative agent of the disease, is autochthonous to riverine, estuarine, and coastal waters, it is unlikely the bacteria can be eradicated from its natural habitat. Prediction of disease, in conjunction with preventive vaccination can reduce the prevalence rate of a disease. Understanding the influence of environmental parameters on growth and proliferation of bacteria is an essential first step in developing prediction methods for outbreaks. Large scale geophysical variables, such as SST and coastal chlorophyll, are often associated with conditions favoring growth of V. cholerae. However, local environmental factors, meaning biological activity in ponds from where the bulk of populations in endemic regions derive water for daily usage, are either neglected or oversimplified. Using data collected from several sites in two geographically distinct locations in South Asia, we have identified critical local environmental factors associated with cholera outbreak. Of 18 environmental variables monitored for water sources in Mathbaria (a coastal site near the Bay of Bengal) and Bakergonj (an inland site) of Bangladesh, water depth and chlorophyll were found to be important factors associated with initiation of cholera outbreaks. Cholera in coastal regions appears to be related to intrusion. However, monsoonal flooding creates conditions for cholera epidemics in inland regions. This may be one of the first attempts to relate in-situ environmental observations with cholera. We anticipate that it will be useful for further development of prediction models in the resource constrained regions.

  10. Co-occurring nonnative woody shrubs have additive and non-additive soil legacies

    DEFF Research Database (Denmark)

    Kuebbing, Sara E.; Patterson, Courtney M.; Classen, Aimee Taylor

    2016-01-01

    shrubs, Lonicera maackii and Ligustrum sinense, in deciduous forests of the southeastern United States. We measured the performance of each nonnative shrub, a native herbaceous community, and a nonnative woody vine in soils conditioned by each shrub singly or together in polyculture. Soils conditioned...... by both nonnative shrubs had non-additive impacts on native and nonnative performance. Root mass of the native herbaceous community was 1.5 times lower and the root mass of the nonnative L. sinense was 1.8 times higher in soils conditioned by both L. maackii and L. sinense than expected based upon growth...... in soils conditioned by either shrub singly. This result indicates that when these two nonnative shrubs co-occur, their influence on soils disproportionally favors persistence of the nonnative L. sinense relative to this native herbaceous community, and could provide an explanation of why native species...

  11. Vegetation Cover Analysis of Hazardous Waste Sites in Utah and Arizona Using Hyperspectral Remote Sensing

    Directory of Open Access Journals (Sweden)

    Mike Serrato

    2012-01-01

    Full Text Available This study investigated the usability of hyperspectral remote sensing for characterizing vegetation at hazardous waste sites. The specific objectives of this study were to: (1 estimate leaf-area-index (LAI of the vegetation using three different methods (i.e., vegetation indices, red-edge positioning (REP, and machine learning regression trees, and (2 map the vegetation cover using machine learning decision trees based on either the scaled reflectance data or mixture tuned matched filtering (MTMF-derived metrics and vegetation indices. HyMap airborne data (126 bands at 2.3 × 2.3 m spatial resolution, collected over the U.S. Department of Energy uranium processing sites near Monticello, Utah and Monument Valley, Arizona, were used. Grass and shrub species were mixed on an engineered disposal cell cover at the Monticello site while shrub species were dominant in the phytoremediation plantings at the Monument Valley site. Regression trees resulted in the best calibration performance of LAI estimation (R2 > 0.80. The use of REPs failed to accurately predict LAI (R2 < 0.2. The use of the MTMF-derived metrics (matched filter scores and infeasibility and a range of vegetation indices in decision trees improved the vegetation mapping when compared to the decision tree classification using just the scaled reflectance. Results suggest that hyperspectral imagery are useful for characterizing biophysical characteristics (LAI and vegetation cover on capped hazardous waste sites. However, it is believed that the vegetation mapping would benefit from the use of higher spatial resolution hyperspectral data due to the small size of many of the vegetation patches ( < 1 m found on the sites.

  12. Vegetation Cover Analysis Of Hazardous Waste Sites In Utah And Arizona Using Hyperspectral Remote Sensing

    International Nuclear Information System (INIS)

    Serrato, M.; Jungho, I.; Jensen, J.; Jensen, R.; Gladden, J.; Waugh, J.

    2012-01-01

    Remote sensing technology can provide a cost-effective tool for monitoring hazardous waste sites. This study investigated the usability of HyMap airborne hyperspectral remote sensing data (126 bands at 2.3 x 2.3 m spatial resolution) to characterize the vegetation at U.S. Department of Energy uranium processing sites near Monticello, Utah and Monument Valley, Arizona. Grass and shrub species were mixed on an engineered disposal cell cover at the Monticello site while shrub species were dominant in the phytoremediation plantings at the Monument Valley site. The specific objectives of this study were to: (1) estimate leaf-area-index (LAI) of the vegetation using three different methods (i.e., vegetation indices, red-edge positioning (REP), and machine learning regression trees), and (2) map the vegetation cover using machine learning decision trees based on either the scaled reflectance data or mixture tuned matched filtering (MTMF)-derived metrics and vegetation indices. Regression trees resulted in the best calibration performance of LAI estimation (R 2 > 0.80). The use of REPs failed to accurately predict LAI (R 2 < 0.2). The use of the MTMF-derived metrics (matched filter scores and infeasibility) and a range of vegetation indices in decision trees improved the vegetation mapping when compared to the decision tree classification using just the scaled reflectance. Results suggest that hyperspectral imagery are useful for characterizing biophysical characteristics (LAI) and vegetation cover on capped hazardous waste sites. However, it is believed that the vegetation mapping would benefit from the use of 1 higher spatial resolution hyperspectral data due to the small size of many of the vegetation patches (< 1m) found on the sites.

  13. VEGETATION COVER ANALYSIS OF HAZARDOUS WASTE SITES IN UTAH AND ARIZONA USING HYPERSPECTRAL REMOTE SENSING

    Energy Technology Data Exchange (ETDEWEB)

    Serrato, M.; Jungho, I.; Jensen, J.; Jensen, R.; Gladden, J.; Waugh, J.

    2012-01-17

    Remote sensing technology can provide a cost-effective tool for monitoring hazardous waste sites. This study investigated the usability of HyMap airborne hyperspectral remote sensing data (126 bands at 2.3 x 2.3 m spatial resolution) to characterize the vegetation at U.S. Department of Energy uranium processing sites near Monticello, Utah and Monument Valley, Arizona. Grass and shrub species were mixed on an engineered disposal cell cover at the Monticello site while shrub species were dominant in the phytoremediation plantings at the Monument Valley site. The specific objectives of this study were to: (1) estimate leaf-area-index (LAI) of the vegetation using three different methods (i.e., vegetation indices, red-edge positioning (REP), and machine learning regression trees), and (2) map the vegetation cover using machine learning decision trees based on either the scaled reflectance data or mixture tuned matched filtering (MTMF)-derived metrics and vegetation indices. Regression trees resulted in the best calibration performance of LAI estimation (R{sup 2} > 0.80). The use of REPs failed to accurately predict LAI (R{sup 2} < 0.2). The use of the MTMF-derived metrics (matched filter scores and infeasibility) and a range of vegetation indices in decision trees improved the vegetation mapping when compared to the decision tree classification using just the scaled reflectance. Results suggest that hyperspectral imagery are useful for characterizing biophysical characteristics (LAI) and vegetation cover on capped hazardous waste sites. However, it is believed that the vegetation mapping would benefit from the use of 1 higher spatial resolution hyperspectral data due to the small size of many of the vegetation patches (< 1m) found on the sites.

  14. Tundra plant above-ground biomass and shrub dominance mapped across the North Slope of Alaska

    Science.gov (United States)

    Berner, Logan T.; Jantz, Patrick; Tape, Ken D.; Goetz, Scott J.

    2018-03-01

    Arctic tundra is becoming greener and shrubbier due to recent warming. This is impacting climate feedbacks and wildlife, yet the spatial distribution of plant biomass in tundra ecosystems is uncertain. In this study, we mapped plant and shrub above-ground biomass (AGB; kg m-2) and shrub dominance (%; shrub AGB/plant AGB) across the North Slope of Alaska by linking biomass harvests at 28 field sites with 30 m resolution Landsat satellite imagery. We first developed regression models (p plant AGB (r 2 = 0.79) and shrub AGB (r 2 = 0.82) based on the normalized difference vegetation index (NDVI) derived from imagery acquired by Landsat 5 and 7. We then predicted regional plant and shrub AGB by combining these regression models with a regional Landsat NDVI mosaic built from 1721 summer scenes acquired between 2007 and 2016. Our approach employed a Monte Carlo uncertainty analysis that propagated sampling and sensor calibration errors. We estimated that plant AGB averaged 0.74 (0.60, 0.88) kg m-2 (95% CI) and totaled 112 (91, 135) Tg across the region, with shrub AGB accounting for ~43% of regional plant AGB. The new maps capture landscape variation in plant AGB visible in high resolution satellite and aerial imagery, notably shrubby riparian corridors. Modeled shrub AGB was strongly correlated with field measurements of shrub canopy height at 25 sites (rs  = 0.88) and with a regional map of shrub cover (rs  = 0.76). Modeled plant AGB and shrub dominance were higher in shrub tundra than graminoid tundra and increased between areas with the coldest and warmest summer air temperatures, underscoring the fact that future warming has the potential to greatly increase plant AGB and shrub dominance in this region. These new biomass maps provide a unique source of ecological information for a region undergoing rapid environmental change.

  15. The importance of ants in cave ecology, with new records and behavioral observations of ants in Arizona caves

    Directory of Open Access Journals (Sweden)

    Robert B. Pape

    2016-09-01

    Full Text Available The importance of ants as elements in cave ecology has been mostly unrecognized. A global list of ant species recorded from caves, compiled from a review of existing literature, is presented. This paper also reviews what is currently known about ants occurring in Arizona (USA caves. The diversity and distribution represented in these records suggests ants are relatively common cave visitors (trogloxenes. A general utilization of caves by ants within both temperate and tropical latitudes may be inferred from this combined evidence. Observations of ant behavior in Arizona caves demonstrate a low level and sporadic, but persistent, use of these habitats and their contained resources by individual ant colonies. Documentation of Neivamyrmex sp. preying on cave-inhabiting arthropods is reported here for the first time. Observations of hypogeic army ants in caves suggests they may not penetrate to great vertical depth in search of prey, but can be persistent occupants in relatively shallow, horizontal sections of caves where they may prey on endemic cave animals. First cave records for ten ant species are reported from Arizona caves. These include two species of Neivamyrmex (N. nigrescens Cresson and Neivamyrmex sp.; Formicidae: Dorylinae, four myrmicines (Pheidole portalensis Wilson, Pheidole cf. porcula Wheeler, Solenopsis aurea Wheeler and Stenamma sp. Westwood, one dolichoderine (Forelius keiferi Wheeler and three formicines (Lasius arizonicus Wheeler, L. sitiens Wilson, and Camponotus sp. Mayr.

  16. Job satisfaction among Arizona adult nurse practitioners.

    Science.gov (United States)

    Schiestel, Charlotte

    2007-01-01

    A literature review for studies of job satisfaction among nurse practitioners (NPs) suggests that the true determinants of job satisfaction have not been discovered. The purpose of this study was to determine job satisfaction among adult health NPs (ANPs) practicing in Arizona. The Misener nurse practitioner job satisfaction scale was mailed to 329 Arizona ANPs who were certified by the Arizona State Board of Nursing (47% response rate). The mean overall satisfaction score was 4.69 out of a possible score of 6.0 for very satisfied. Differences in employer type, gender, annual income, membership in professional nursing organization, or full-time versus part-time employment status did not result in significantly different scores on the job satisfaction scale in this group. A deep and sustained nursing shortage, the exodus of experienced nurses from the profession, and a projected shortage of primary care providers have generated interest among professional groups, private and government healthcare commissions, and the healthcare industry in determining what factors may influence an individual to choose and remain active in nursing practice. Researchers, educators, employers, and the healthcare industry must look beyond well-worn assumptions about job satisfaction to explore what the individual NP finds satisfying about his or her role.

  17. University of Arizona Compressed Air Energy Storage

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, Joseph [Univ. of Arizona, Tucson, AZ (United States); Muralidharan, Krishna [Univ. of Arizona, Tucson, AZ (United States)

    2012-12-31

    Boiled down to its essentials, the grant’s purpose was to develop and demonstrate the viability of compressed air energy storage (CAES) for use in renewable energy development. While everyone agrees that energy storage is the key component to enable widespread adoption of renewable energy sources, the development of a viable scalable technology has been missing. The Department of Energy has focused on expanded battery research and improved forecasting, and the utilities have deployed renewable energy resources only to the extent of satisfying Renewable Portfolio Standards. The lack of dispatchability of solar and wind-based electricity generation has drastically increased the cost of operation with these components. It is now clear that energy storage coupled with accurate solar and wind forecasting make up the only combination that can succeed in dispatchable renewable energy resources. Conventional batteries scale linearly in size, so the price becomes a barrier for large systems. Flow batteries scale sub-linearly and promise to be useful if their performance can be shown to provide sufficient support for solar and wind-base electricity generation resources. Compressed air energy storage provides the most desirable answer in terms of scalability and performance in all areas except efficiency. With the support of the DOE, Tucson Electric Power and Science Foundation Arizona, the Arizona Research Institute for Solar Energy (AzRISE) at the University of Arizona has had the opportunity to investigate CAES as a potential energy storage resource.

  18. September 2017 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2017-09-01

    Full Text Available No abstract available. Article truncated at 150 words. The September 2017 Arizona Thoracic Society meeting was held on Wednesday, September 27, 2017 at the HonorHealth Rehabilitation Hospital beginning at 6:30 PM. This was a dinner meeting with case presentations. There were 16 in attendance representing the pulmonary, critical care, sleep, and radiology communities. There was a discussion of the Tobacco 21 bill which had been introduced the last session in the Arizona State Legislature. Since it seems likely that the bill will be reintroduced, the Arizona Thoracic Society will support the bill in the future. Dr. Rick Robbins announced that the SWJPCC has applied to be included in PubMed. In addition, Dr. Robbins was assigned the task of tracking down the campaign contributions to congressional members from the tobacco PAC before the next election. There were 7 case presentations: 1.\tAshley L. Garrett, MD, pulmonary fellow at Mayo, presented an elderly man with insulin-dependent diabetes who felt he …

  19. April 2014 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2014-04-01

    Full Text Available No abstract available. Article truncated at 150 words. The April 2014 Arizona Thoracic Society meeting was held on Wednesday, 4/23/2014 at Scottsdale Shea Hospital beginning at 6:30 PM. There were 15 in attendance representing the pulmonary, critical care, sleep, pathology and radiology communities. It was announced that there will be a wine tasting with the California, New Mexico and Colorado Thoracic Societies at the American Thoracic Society International Meeting. The tasting will be led by Peter Wagner and is scheduled for the Cobalt Room in the Hilton San Diego Bayfront on Tuesday, May 20, from 4-8 PM. Guideline development was again discussed. The consensus was to await publication of the IDSA Cocci Guidelines and respond appropriately. George Parides, Arizona Chapter Representative, gave a presentation on Hill Day. Representatives of the Arizona, New Mexico and Washington Thoracic Societies met with their Congressional delegations, including Rep. David Schweikert, to discuss the Cigar Bill, NIH funding, and the Medicare Sustainable Growth ...

  20. Shifts in species interactions due to the evolution of functional differences between endemics and non-endemics: an endemic syndrome hypothesis.

    Directory of Open Access Journals (Sweden)

    Courtney E Gorman

    Full Text Available Species ranges have been shifting since the Pleistocene, whereby fragmentation, isolation, and the subsequent reduction in gene flow have resulted in local adaptation of novel genotypes and the repeated evolution of endemic species. While there is a wide body of literature focused on understanding endemic species, very few studies empirically test whether or not the evolution of endemics results in unique function or ecological differences relative to their widespread congeners; in particular while controlling for environmental variation. Using a common garden composed of 15 Eucalyptus species within the subgenus Symphyomyrtus (9 endemic to Tasmania, 6 non-endemic, here we hypothesize and show that endemic species are functionally and ecologically different from non-endemics. Compared to non-endemics, endemic Eucalyptus species have a unique suite of functional plant traits that have extended effects on herbivores. We found that while endemics occupy many diverse habitats, they share similar functional traits potentially resulting in an endemic syndrome of traits. This study provides one of the first empirical datasets analyzing the functional differences between endemics and non-endemics in a common garden setting, and establishes a foundation for additional studies of endemic/non-endemic dynamics that will be essential for understanding global biodiversity in the midst of rapid species extinctions and range shifts as a consequence of global change.

  1. Range Expansion of Moose in Arctic Alaska Linked to Warming and Increased Shrub Habitat.

    Directory of Open Access Journals (Sweden)

    Ken D Tape

    Full Text Available Twentieth century warming has increased vegetation productivity and shrub cover across northern tundra and treeline regions, but effects on terrestrial wildlife have not been demonstrated on a comparable scale. During this period, Alaskan moose (Alces alces gigas extended their range from the boreal forest into tundra riparian shrub habitat; similar extensions have been observed in Canada (A. a. andersoni and Eurasia (A. a. alces. Northern moose distribution is thought to be limited by forage availability above the snow in late winter, so the observed increase in shrub habitat could be causing the northward moose establishment, but a previous hypothesis suggested that hunting cessation triggered moose establishment. Here, we use recent changes in shrub cover and empirical relationships between shrub height and growing season temperature to estimate available moose habitat in Arctic Alaska c. 1860. We estimate that riparian shrubs were approximately 1.1 m tall c. 1860, greatly reducing the available forage above the snowpack, compared to 2 m tall in 2009. We believe that increases in riparian shrub habitat after 1860 allowed moose to colonize tundra regions of Alaska hundreds of kilometers north and west of previous distribution limits. The northern shift in the distribution of moose, like that of snowshoe hares, has been in response to the spread of their shrub habitat in the Arctic, but at the same time, herbivores have likely had pronounced impacts on the structure and function of these shrub communities. These northward range shifts are a bellwether for other boreal species and their associated predators.

  2. Hydraulic lift through transpiration suppression in shrubs from two arid ecosystems: patterns and control mechanisms.

    Science.gov (United States)

    Prieto, Iván; Martínez-Tillería, Karina; Martínez-Manchego, Luis; Montecinos, Sonia; Pugnaire, Francisco I; Squeo, Francisco A

    2010-08-01

    Hydraulic lift (HL) is the passive movement of water through the roots from deep wet to dry shallow soil layers when stomata are closed. HL has been shown in different ecosystems and species, and it depends on plant physiology and soil properties. In this study we explored HL patterns in several arid land shrubs, and developed a simple model to simulate the temporal evolution and magnitude of HL during a soil drying cycle under relatively stable climatic conditions. This model was then used to evaluate the influence of soil texture on the quantity of water lifted by shrubs in different soil types. We conducted transpiration suppression experiments during spring 2005 in Chile and spring 2008 in Spain on five shrub species that performed HL, Flourensia thurifera, Senna cumingii and Pleocarphus revolutus (Chile), Retama sphaerocarpa and Artemisia barrelieri (Spain). Shrubs were covered with a black, opaque plastic fabric for a period of 48-72 h, and soil water potential was recorded at different depths under the shrubs. While the shrubs remained covered, water potential continuously increased in shallow soil layers until the cover was removed. The model output indicated that the amount of water lifted by shrubs is heavily dependent on soil texture, as shrubs growing in loamy soils redistributed up to 3.6 times more water than shrubs growing on sandy soils. This could be an important consideration for species growing in soils with different textures, as their ability to perform HL would be context dependent.

  3. Disentangling the effects of shrubs and herbivores on tree regeneration in a dry Chaco forest (Argentina).

    Science.gov (United States)

    Tálamo, Andrés; Barchuk, Alicia H; Garibaldi, Lucas A; Trucco, Carlos E; Cardozo, Silvana; Mohr, Federico

    2015-07-01

    Successful persistence of dry forests depends on tree regeneration, which depends on a balance of complex biotic interactions. In particular, the relative importance and interactive effects of shrubs and herbivores on tree regeneration are unclear. In a manipulative study, we investigated if thornless shrubs have a direct net effect, an indirect positive effect mediated by livestock, and/or an indirect negative effect mediated by small vertebrates on tree regeneration of two key species of Chaco forest (Argentina). In a spatial association study, we also explored the existence of net positive interactions from thorny and thornless shrubs. The number of Schinopsis lorentzii seedlings was highest under artificial shade with native herbivores and livestock excluded. Even excluding livestock, no seedlings were found with natural conditions (native herbivores present with natural shade or direct sunlight) at the end of the experiment. Surprisingly, seedling recruitment was not enhanced under thornless shrubs, because there was a complementary positive effect of shade and interference. Moreover, thornless shrubs had neither positive nor negative effects on regeneration of S. lorentzii. Regeneration of Aspidosperma quebracho-blanco was minimal in all treatments. In agreement with the experiment, spatial distributions of saplings of both tree species were independent of thornless shrubs, but positively associated with thorny shrubs. Our results suggest that in general thornless shrubs may have a negligible effect and thorny shrubs a net positive effect on tree regeneration in dry forests. These findings provide a conceptual framework for testing the impact of biotic interactions on seedling recruitment in other dry forests.

  4. Polymorphic microsatellite markers in the invasive shrub Buddleja davidii (Scrophulariaceae).

    Science.gov (United States)

    Schreiter, Susanne; Ebeling, Susan K; Durka, Walter

    2011-02-01

    Microsatellite primers were developed for the invasive plant Buddleja davidii, a Chinese shrub that is an invader in most other continents. An invasive population was analyzed using eight di- and tetranucleotide microsatellite loci. The number of alleles per locus ranged from 5 to 14. Due to polyploidy, exact genotypes could not be determined. Progeny arrays were used to study the outcrossing rate using presence/absence data of alleles resulting in an estimate of multilocus outcrossing rate of 93%. The markers were successfully tested in five congeneric species. The results indicate the utility of these loci in future studies of population genetics and breeding systems in B. davidii and in congeneric species.

  5. Temperature-induced recruitment pulses of Arctic dwarf shrub communities

    Czech Academy of Sciences Publication Activity Database

    Büntgen, Ulf; Hellmann, L.; Tegel, W.; Normand, S.; Myers-Smith, I.; Kirdyanov, A. V.; Nievergelt, D.; Schweingruber, F. H.

    2015-01-01

    Roč. 103, č. 2 (2015), s. 489-501 ISSN 0022-0477 R&D Projects: GA MŠk(CZ) EE2.3.20.0248 Institutional support: RVO:67179843 Keywords : recent climate-change * tree-line * environmental-change * forest limit * northern siberia * pinus-sylvestris * kola-peninsula * carbon-cycle * picea-abies * polar urals * Arctic tundra * cambial activity * climate change * dendroecology * dwarf shrubs * East Greenland * plant longevity * plant population and community dynamics * vegetation dynamics * wood anatomy Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 6.180, year: 2015

  6. What moves you Arizona : long-range transportation plan : 2010-2035.

    Science.gov (United States)

    2011-11-01

    "What Moves You Arizona is the Arizona Department of Transportations (ADOT) Long-Range Transportation Plan (LRTP). The LRTP, or Plan, defines visionary, yet pragmatic, investment choices Arizona will make over the next 25 years to maintain a...

  7. Non-endemic cases of lymphatic filariasis.

    Science.gov (United States)

    Jones, Robert T

    2014-11-01

    Several cases of lymphatic filariasis (LF) have been reported in non-endemic countries due to travellers, military personnel and expatriates spending time in and returning from endemic areas, as well as immigrants coming from these regions. These cases are reviewed to assess the scale and context of non-endemic presentations and to consider the biological factors underlying their relative paucity. Cases reported in the English, French, Spanish and Portuguese literature during the last 30 years were examined through a search of the PubMed, ProMED-mail and TropNet resources. The literature research revealed 11 cases of lymphatic filariasis being reported in non-endemic areas. The extent of further infections in recent migrants to non-endemic countries was also revealed through the published literature. The life-cycle requirements of Wuchereria and Brugia species limit the extent of transmission of LF outside of tropical regions. However, until elimination, programmes are successful in managing the disease, there remains a possibility of low rates of infection being reported in non-endemic areas, and increased international travel can only contribute to this phenomenon. Physicians need to be aware of the signs and symptoms of lymphatic filariasis, and infection should be considered in the differential diagnosis of people with a relevant travel history. © 2014 John Wiley & Sons Ltd.

  8. Deciduous shrubs for ozone bioindication: Hibiscus syriacus as an example

    Energy Technology Data Exchange (ETDEWEB)

    Paoletti, Elena [Institut Plant Protection (IPP), National Council Research (CNR), Via Madonna del Piano 10, 50019 Sesto Fiorentino, Florence (Italy)], E-mail: e.paoletti@ipp.cnr.it; Ferrara, Anna Maria [Istituto per le Piante da Legno e l' Ambiente (IPLA), Corso Casale 476, 10132 Turin (Italy); Calatayud, Vicent; Cervero, Julia [Fundacion C.E.A.M., Charles R. Darwin 14, Parc Tecnologic, 46980 Paterna, Valencia (Spain); Giannetti, Fabio [Istituto per le Piante da Legno e l' Ambiente (IPLA), Corso Casale 476, 10132 Turin (Italy); Sanz, Maria Jose [Fundacion C.E.A.M., Charles R. Darwin 14, Parc Tecnologic, 46980 Paterna, Valencia (Spain); Manning, William J. [Department of Plant, Soil and Insect Sciences, University of Massachusetts, Amherst, MA 01003-9320 (United States)

    2009-03-15

    Ozone-like visible injury was detected on Hibiscus syriacus plants used as ornamental hedges. Weekly spray of the antiozonant ethylenediurea (EDU, 300 ppm) confirmed that the injury was induced by ambient ozone. EDU induced a 75% reduction in visible injury. Injury was more severe on the western than on the eastern exposure of the hedge. This factor of variability should be considered in ozone biomonitoring programmes. Seeds were collected and seedlings were artificially exposed to ozone in filtered vs. not-filtered (+30 ppb) Open-Top Chambers. The level of exposure inducing visible injury in the OTC seedlings was lower than that in the ambient-grown hedge. The occurrence of visible injury in the OTC confirmed that the ozone sensitivity was heritable and suggested that symptomatic plants of this deciduous shrub population can be successfully used as ozone bioindicators. EDU is recommended as a simple tool for diagnosing ambient ozone visible injury on field vegetation. - An Italian population of the deciduous shrub Hibiscus syriacus, a common ornamental species in temperate zones, is recommended as ozone bioindicator.

  9. Deciduous shrubs for ozone bioindication: Hibiscus syriacus as an example

    International Nuclear Information System (INIS)

    Paoletti, Elena; Ferrara, Anna Maria; Calatayud, Vicent; Cervero, Julia; Giannetti, Fabio; Sanz, Maria Jose; Manning, William J.

    2009-01-01

    Ozone-like visible injury was detected on Hibiscus syriacus plants used as ornamental hedges. Weekly spray of the antiozonant ethylenediurea (EDU, 300 ppm) confirmed that the injury was induced by ambient ozone. EDU induced a 75% reduction in visible injury. Injury was more severe on the western than on the eastern exposure of the hedge. This factor of variability should be considered in ozone biomonitoring programmes. Seeds were collected and seedlings were artificially exposed to ozone in filtered vs. not-filtered (+30 ppb) Open-Top Chambers. The level of exposure inducing visible injury in the OTC seedlings was lower than that in the ambient-grown hedge. The occurrence of visible injury in the OTC confirmed that the ozone sensitivity was heritable and suggested that symptomatic plants of this deciduous shrub population can be successfully used as ozone bioindicators. EDU is recommended as a simple tool for diagnosing ambient ozone visible injury on field vegetation. - An Italian population of the deciduous shrub Hibiscus syriacus, a common ornamental species in temperate zones, is recommended as ozone bioindicator

  10. Does NDVI reflect variation in the structural attributes associated with increasing shrub dominance in arctic tundra?

    International Nuclear Information System (INIS)

    Boelman, Natalie T; Gough, Laura; McLaren, Jennie R; Greaves, Heather

    2011-01-01

    This study explores relationships between the normalized difference vegetation index (NDVI) and structural characteristics associated with deciduous shrub dominance in arctic tundra. Our structural measures of shrub dominance are stature, branch abundance, aerial per cent woody stem cover (deciduous and evergreen species), and per cent deciduous shrub canopy cover. All measurements were taken across a suite of transects that together represent a gradient of deciduous shrub height. The transects include tussock tundra shrub and riparian shrub tundra communities located in the northern foothills of the Brooks Range, in northern Alaska. Plot-level NDVI measurements were made in 2010 during the snow-free period prior to deciduous shrub leaf-out (early June, NDVI pre-leaf ), at the point in the growing season when canopy NDVI has reached half of its maximum growing season value (mid-June, NDVI demi-leaf ) and during the period of maximum leaf-out (late July, NDVI peak-leaf ). We found that: (1) NDVI pre-leaf is best suited to capturing variation in the per cent woody stem cover, maximum shrub height, and branch abundance, particularly between 10 and 50 cm height in the canopy; (2) NDVI peak-leaf is best suited to capturing variation in deciduous canopy cover; and (3) NDVI demi-leaf does not capture variability in any of our measures of shrub dominance. These findings suggest that in situ NDVI measurements made prior to deciduous canopy leaf-out could be used to identify small differences in maximum shrub height, woody stem cover, and branch abundance (particularly between 10 and 50 cm height in the canopy). Because shrubs are increasing in size and regional extent in several regions of the Arctic, investigation into spectrally based tools for monitoring these changes are worthwhile as they provide a first step towards development of remotely sensed techniques for quantifying associated changes in regional carbon cycling, albedo, radiative energy balance, and wildlife

  11. Tundra shrub effects on growing season energy and carbon dioxide exchange

    Science.gov (United States)

    Lafleur, Peter M.; Humphreys, Elyn R.

    2018-05-01

    Increased shrub cover on the Arctic tundra is expected to impact ecosystem-atmosphere exchanges of carbon and energy resulting in feedbacks to the climate system, yet few direct measurements of shrub tundra-atmosphere exchanges are available to corroborate expectations. Here we present energy and carbon dioxide (CO2) fluxes measured using the eddy covariance technique over six growing seasons at three closely located tundra sites in Canada’s Low Arctic. The sites are dominated by the tundra shrub Betula glandulosa, but percent cover varies from 17%–60% and average shrub height ranges from 18–59 cm among sites. The site with greatest percent cover and height had greater snow accumulation, but contrary to some expectations, it had similar late-winter albedo and snow melt dates compared to the other two sites. Immediately after snowmelt latent heat fluxes increased more slowly at this site compared to the others. Yet by the end of the growing season there was little difference in cumulative latent heat flux among the sites, suggesting evapotranspiration was not increased with greater shrub cover. In contrast, lower albedo and less soil thaw contributed to greater summer sensible heat flux at the site with greatest shrub cover, resulting in greater total atmospheric heating. Net ecosystem exchange of CO2 revealed the potential for enhanced carbon cycling rates under greater shrub cover. Spring CO2 emissions were greatest at the site with greatest percent cover of shrubs, as was summer net uptake of CO2. The seasonal net sink for CO2 was ~2 times larger at the site with the greatest shrub cover compared to the site with the least shrub cover. These results largely agree with expectations that the growing season feedback to the atmosphere arising from shrub expansion in the Arctic has the potential to be negative for CO2 fluxes but positive for turbulent energy fluxes.

  12. New hairworm (Nematomorpha, Gordiida) species described from the Arizona Madrean Sky Islands.

    Science.gov (United States)

    Swanteson-Franz, Rachel J; Marquez, Destinie A; Goldstein, Craig I; Andreas Schmidt-Rhaesa; Bolek, Matthew G; Hanelt, Ben

    2018-01-01

    Gordiids, or freshwater hairworms, are members of the phylum Nematomorpha that use terrestrial definitive hosts (arthropods) and live as adults in rivers, lakes, or streams. The genus Paragordius consists of 18 species, one of which was described from the Nearctic in 1851. More than 150 years later, we are describing a second Paragordius species from a unique habitat within the Nearctic; the Madrean Sky Island complex. The Madrean Sky Islands are a series of isolated high mountains in northern Mexico and the southwestern United States (Arizona and New Mexico), and are well known for their high diversity and endemicity. The new species is described based on both molecular data (COI barcoding) and morphological characters of the eggs, larvae, cysts, and adults. Adult females have unique small oblong mounds present on the interior of the trifurcating lobes with randomly dispersed long hairs extending from the furrows between the mounds. Marked genetic differences support observed morphological differences. This species represents the second new hairworm to be described from the Madrean Sky Islands, and it may represent the first endemic hairworm from this biodiversity hotspot.

  13. Gulf-Wide Information System, Environmental Sensitivity Index Scrub-Shrub and Wetlands, Geographic NAD83, LDWF (2001) [esi_scrub-shrub_wetland_LDWF_2001

    Data.gov (United States)

    Louisiana Geographic Information Center — This data set contains Environmental Sensitivity Index (ESI) scrub-shrub and wetlands data of coastal Louisiana. The ESI is a classification and ranking system,...

  14. How Arizona's Dropout Crisis Affects Communities, Creates Economic Losses for the State of Arizona

    Science.gov (United States)

    WestEd, 2014

    2014-01-01

    One-in-five of Arizona's youth did not complete high school and a similarly large proportion of the state's youth is disconnected from either work or education. These youth face higher risks of unemployment and economic insecurity and are more reliant on government supports. This situation, which fails to ensure that the state's youth are…

  15. Examining Arizona's Policy Response Post "Flores v. Arizona" in Educating K-12 English Language Learners

    Science.gov (United States)

    Jimenez-Silva, Margarita; Gomez, Laura; Cisneros, Jesus

    2014-01-01

    This article provides an analysis of Arizona's policy response in educating English language learners by conducting a narrative review. A critical Latina/o theory approach was used to analyze the data. This study reveals 5 salient policy responses: (a) severely limit bilingual education, (b) develop controversial funding solutions, (c) implement a…

  16. The invasive shrub Piper aduncum in Papua New Guinea: a review

    NARCIS (Netherlands)

    Hartemink, A.E.

    2010-01-01

    HARTEMINK AE. 2010. The invasive shrub Piper aduneum in Papua New Guinea: a review. Piper aduncum is a shrub native to Central America. It is found in most Central and South American countries and also in the Caribbean and southern Florida (USA). In Asia and the Pacific, P aduncum occurs in

  17. Shrubs in the cold : interactions between vegetation, permafrost and climate in Siberian tundra

    NARCIS (Netherlands)

    Blok, D.

    2011-01-01

    The Arctic is experiencing strong increases in air temperature during the last decades. High-latitude tundra regions are very responsive to changes in temperature and may cause a shift in tundra vegetation composition towards greater dominance of deciduous shrubs. With increasing deciduous shrub

  18. Shrub encroachment alters sensitivity of soil respiration to temperature and moisture 2115

    Science.gov (United States)

    Shrub encroachment into grasslands creates a mosaic of different soil microsites ranging from open spaces to well-developed shrub canopies, and it is unclear how this affects the spatial variability in soil respiration characteristics, such as the sensitivity to soil temperature and moisture. This i...

  19. Food for early succession birds: relationships among arthropods, shrub vegetation, and soil

    Science.gov (United States)

    Richard N. Conner; Daniel Saenz; D. Brent Burt

    2006-01-01

    During spring and early summer, shrub- and herbaceous-level vegetation provides nesting and foraging habitat for many shrub-habitat birds. We examined relationships among arthropod biomass and abundance, foliage leaf surface area and weight, vegetation ground cover, soil characteristics, relative humidity, and temperature to evaluate what factors may influence...

  20. Degree of susceptibility of industrial gases of tree and shrub species

    Energy Technology Data Exchange (ETDEWEB)

    Dobrovoljskii, I A

    1952-01-01

    The trees and shrubs of the iron smelting region of Krivoi Rog, in the Ukraine, were surveyed to determine susceptibility to air pollution damage. Most of the observations were made in parks and green belts in industrial areas. A classification of tree and shrub species is presented; they are separated into three classes according to their susceptibility to air pollutant injury.

  1. First-order fire effects on herbs and Shrubs: present knowledge and process modeling needs

    Science.gov (United States)

    Kirsten Stephan; Melanie Miller; Matthew B. Dickinson

    2010-01-01

    Herbaceous plants and shrubs have received little attention in terms of fire effects modeling despite their critical role in ecosystem integrity and resilience after wildfires and prescribed burns. In this paper, we summarize current knowledge of direct effects of fire on herb and shrub (including cacti) vegetative tissues and seed banks, propose key components for...

  2. On the influence of shrub height and expansion on northern high latitude climate

    International Nuclear Information System (INIS)

    Bonfils, C J W; Phillips, T J; Cameron-Smith, P; Lawrence, D M; Riley, W J; Subin, Z M

    2012-01-01

    There is a growing body of empirical evidence documenting the expansion of shrub vegetation in the circumpolar Arctic in response to climate change. Here, we conduct a series of idealized experiments with the Community Climate System Model to analyze the potential impact on boreal climate of a large-scale tundra-to-shrub conversion. The model responds to an increase in shrub abundance with substantial atmospheric heating arising from two seasonal land–atmosphere feedbacks: a decrease in surface albedo and an evapotranspiration-induced increase in atmospheric moisture content. We demonstrate that the strength and timing of these feedbacks are sensitive to shrub height and the time at which branches and leaves protrude above the snow. Taller and aerodynamically rougher shrubs lower the albedo earlier in the spring and transpire more efficiently than shorter shrubs. These mechanisms increase, in turn, the strength of the indirect sea-ice albedo and ocean evaporation feedbacks contributing to additional regional warming. Finally, we find that an invasion of tall shrubs tends to systematically warm the soil, deepen the active layer, and destabilize the permafrost (with increased formation of taliks under a future scenario) more substantially than an invasion of short shrubs. (letter)

  3. Mapping snags and understory shrubs for LiDAR based assessment of wildlife habitat suitability

    Science.gov (United States)

    Sebastian Martinuzzi; Lee A. Vierling; William A. Gould; Michael J. Falkowski; Jeffrey S. Evans; Andrew T. Hudak; Kerri T. Vierling

    2009-01-01

    The lack of maps depicting forest three-dimensional structure, particularly as pertaining to snags and understory shrub species distribution, is a major limitation for managing wildlife habitat in forests. Developing new techniques to remotely map snags and understory shrubs is therefore an important need. To address this, we first evaluated the use of LiDAR data for...

  4. HIGH FOLIAR NITROGEN IN DESERT SHRUBS: AN IMPORTANT ECOSYSTEM TRAIT OR DEFECTIVE DESERT DOCTRINE?

    Science.gov (United States)

    Nitrogen concentrations in green and senesced leaves of perennial desert shrubs were compiled from a worldwide literature search to test the validity of the doctrine that desert shrubs produce foliage and leaf litter much richer in nitrogen than that in the foliage of plants from...

  5. Influence of shrubs on soil chemical properties in Alxa desert steppe, China

    Science.gov (United States)

    Hua Fu; Shifang Pei; Yaming Chen; Changgui Wan

    2007-01-01

    Alxa desert steppe is one of severely the degraded rangelands in the Northwest China. Shrubs, as the dominant life form in the desert steppe, play an important role in protecting this region from further desertification. Chemical properties of three soil layers (0 to 10, 10 to 20 and 20 to 30 cm) at three locations (the clump center [A], in the periphery of shrub...

  6. Effects of cattle and rabbit grazing on clonal expansion of spiny shrubs in wood-pastures

    NARCIS (Netherlands)

    Smit, Christian; Bakker, Elisabeth S.; Apol, M. Emile F.; Olff, Han

    2010-01-01

    Spiny shrubs protect non-defended plants against herbivores. Therefore, they play a role for the diversity in grazed ecosystems. While the importance of these keystone nurse shrubs is presently recognized, little is known about the factors controlling them. This knowledge is required to understand

  7. Resilience of arctic mycorrhizal fungal communities after wildfire facilitated by resprouting shrubs

    Science.gov (United States)

    Rebecca E. Hewitt; Elizabeth Bent; Teresa N. Hollingsworth; F. Stuart Chapin; D. Lee Taylor

    2013-01-01

    Climate-induced changes in the tundra fire regime are expected to alter shrub abundance and distribution across the Arctic. However, little is known about how fire may indirectly impact shrub performance by altering mycorrhizal symbionts. We used molecular tools, including ARISA and ITS sequencing, to characterize the mycorrhizal communities on resprouting ...

  8. Atlas of United States Trees, Volume 2: Alaska Trees and Common Shrubs.

    Science.gov (United States)

    Viereck, Leslie A.; Little, Elbert L., Jr.

    This volume is the second in a series of atlases describing the natural distribution or range of native tree species in the United States. The 82 species maps include 32 of trees in Alaska, 6 of shrubs rarely reaching tree size, and 44 more of common shrubs. More than 20 additional maps summarize environmental factors and furnish general…

  9. The Relationship between an Invasive Shrub and Soil Moisture: Seasonal Interactions and Spatially Covarying Relations

    Directory of Open Access Journals (Sweden)

    Yuhong He

    2014-09-01

    Full Text Available Recent studies indicate that positive relationships between invasive plants and soil can contribute to further plant invasions. However, it remains unclear whether these relations remain unchanged throughout the growing season. In this study, spatial sequences of field observations along a transect were used to reveal seasonal interactions and spatially covarying relations between one common invasive shrub (Tartarian Honeysuckle, Lonicera tatarica and soil moisture in a tall grassland habitat. Statistical analysis over the transect shows that the contrast between soil moisture in shrub and herbaceous patches vary with season and precipitation. Overall, a negatively covarying relationship between shrub and soil moisture (i.e., drier surface soils at shrub microsites exists during the very early growing period (e.g., May, while in summer a positively covarying phenomenon (i.e., wetter soils under shrubs is usually evident, but could be weakened or vanish during long precipitation-free periods. If there is sufficient rainfall, surface soil moisture and leaf area index (LAI often spatially covary with significant spatial oscillations at an invariant scale (which is governed by the shrub spatial pattern and is about 8 m, but their phase relation in space varies with season, consistent with the seasonal variability of the co-varying phenomena between shrub invasion and soil water content. The findings are important for establishing a more complete picture of how shrub invasion affects soil moisture.

  10. Phenotypic sex ratios of Atriplex canescens shrubs in relation to cattle browsing

    Science.gov (United States)

    Andres F. Cibils; David M. Swift; Richard H. Hart

    2001-01-01

    Previous studies conducted at our research site on the shortgrass steppe in Colorado showed that phenotypic sex ratios of tetraploid fourwing saltbush (Atriplex canescens Pursh [Nutt]) shrubs were less female biased in grazed pastures than in adjacent exclosures. The potential effects of cattle browsing on shrub sex ratios were studied both in the field and in a...

  11. Density and Habitat Relationships of the Endemic White Mountain Fritillary (Boloria chariclea montinus (Lepidoptera: Nymphalidae

    Directory of Open Access Journals (Sweden)

    Kent P. McFarland

    2017-06-01

    Full Text Available We conducted point counts in the alpine zone of the Presidential Range of the White Mountains, New Hampshire, USA, to estimate the distribution and density of the rare endemic White Mountain Fritillary (Boloria chariclea montinus. Incidence of occurrence and density of the endemic White Mountain Fritillary during surveys in 2012 and 2013 were greatest in the herbaceous-snowbank plant community. Densities at points in the heath-shrub-rush plant community were lower, but because this plant community is more widespread in the alpine zone, it likely supports the bulk of adult fritillaries. White Mountain Fritillary used cushion-tussock, the other alpine plant community suspected of providing habitat, only sparingly. Detectability of White Mountain Fritillaries varied as a consequence of weather conditions during the survey and among observers, suggesting that raw counts yield biased estimates of density and abundance. Point counts, commonly used to study and monitor populations of birds, were an effective means of sampling White Mountain Fritillary in the alpine environment where patches of habitat are small, irregularly shaped, and widely spaced, rendering line-transect methods inefficient and difficult to implement.

  12. Transformational Leadership and Teacher Motivation in Southwestern Arizona High Schools

    Science.gov (United States)

    Reynolds, Catherine L.

    2009-01-01

    The purpose of this study was to explore the relationship between transformational leadership and teacher motivation in Southwestern Arizona high schools. Teachers in a school district in Southwestern Arizona comprised of high schools were surveyed using two instruments, Leithwood and Jantzi's (1998) The Leadership and Management of Schools in…

  13. The impact of Arizona Highways Magazine on tourism.

    Science.gov (United States)

    2012-03-01

    The purpose of this study was to: 1) examine the effect of Arizona Highways Magazine (AHM) on tourism, 2) determine trip : characteristics of AHM subscribers traveling in Arizona, and 3) calculate a benefit/cost ratio for AHM based on the : magazine...

  14. To Learn and Earn: Arizona's Unfinished Business in Human Capital

    Science.gov (United States)

    Welch, Nancy

    2009-01-01

    Raising Arizona was the challenge of the 20th century. Sustaining Arizona is now the challenge of the 21st. A crucial part of that task is not just understanding today's knowledge economy, but mastering it. Ray and Charles Eames, the creative geniuses behind many iconic 20th century designs, debuted their film "Powers of 10" in 1977. In…

  15. Innovations in Arizona's Accountability Policies and Frameworks for Alternative Schools

    Science.gov (United States)

    Schlessman, Amy

    2014-01-01

    This study presents Arizona's innovations in academic accountability policy and academic accountability frameworks for alternative schools. A timeline of statutes and regulations including the State Board of Education approved alternative school definition provides Arizona's context for alternative school accountability policy and frameworks.…

  16. 7 CFR 1131.2 - Arizona marketing area.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Arizona marketing area. 1131.2 Section 1131.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Milk), DEPARTMENT OF AGRICULTURE MILK IN THE ARIZONA MARKETING AREA Order Regulating...

  17. 32 CFR 705.31 - USS Arizona Memorial, Pearl Harbor.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 5 2010-07-01 2010-07-01 false USS Arizona Memorial, Pearl Harbor. 705.31... NAVY REGULATIONS AND OFFICIAL RECORDS PUBLIC AFFAIRS REGULATIONS § 705.31 USS Arizona Memorial, Pearl Harbor. (a) Limited space and the desirability of keeping the Memorial simple and dignified require the...

  18. Arizona TeleMedicine Network: System Procurement Specifications.

    Science.gov (United States)

    Atlantic Research Corp., Alexandria, VA.

    Providing general specifications and system descriptions for segments within the Arizona TeleMedicine Project (a telecommunication system designed to deliver health services to rurally isolated American Indians in Arizona), this document, when used with the appropriate route segment document, will completely describe the project's required…

  19. Untangling the web...spiders in Arizona fields

    Science.gov (United States)

    Many kinds of arthropod natural enemies (predators and parasitoids) inhabit crop fields in Arizona and can have a large negative impact on several pest insect species that also infest these crops. Many different species of spiders are common in cotton, alfalfa and other crops in Arizona. Among the ...

  20. High precipitation and seeded species competition reduce seeded shrub establishment during dryland restoration.

    Science.gov (United States)

    Rinella, Matthew J; Hammond, Darcy H; Bryant, Ana-Elisa M; Kozar, Brian J

    2015-06-01

    Drylands comprise 40% of Earth's land mass and are critical to food security, carbon sequestration, and threatened and endangered wildlife. Exotic weed invasions, overgrazing, energy extraction, and other factors have degraded many drylands, and this has placed an increased emphasis on dryland restoration. The increased restoration focus has generated a wealth of experience, innovations and empirical data, yet the goal of restoring diverse, native, dryland plant assemblages composed of grasses, forbs, and shrubs has generally proven beyond reach. Of particular concern are shrubs, which often fail to establish or establish at trivially low densities. We used data from two Great Plains, USA coal mines to explore factors regulating shrub establishment. Our predictor data related to weather and restoration (e.g., seed rates, rock cover) variables, and our response data described shrub abundances on fields of the mines. We found that seeded non-shrubs, especially grasses, formed an important competitive barrier to shrub establishment: With every one standard deviation increase in non-shrub seed rate, the probability shrubs were present decreased ~0.1 and shrub cover decreased ~35%. Since new fields were seeded almost every year for > 20 years, the data also provided a unique opportunity to explore effects of stochastic drivers (i.e., precipitation, year effects). With every one standard deviation increase in precipitation the first growing season following seeding, the probability shrubs were present decreased ~0.07 and shrub cover decreased ~47%. High precipitation appeared to harm shrubs by increasing grass growth/competition. Also, weak evidence suggested shrub establishment was better in rockier fields where grass abundance/competition was lower. Multiple lines of evidence suggest reducing grass seed rates below levels typically used in Great Plains restoration would benefit shrubs without substantially impacting grass stand development over the long term. We used

  1. Brown-headed Cowbird parasitism of the Black-throated Sparrow in central Arizona

    Science.gov (United States)

    Johnson, M.J.; van Riper, Charles

    2004-01-01

    From 1994-1996 we investigated effects of Brown-headed Cowbird (Molothrus ater) parasitism on Black-throated Sparrow (Amphispiza bilineata) nesting success in the Verde Valley of central Arizona. Of 56 Black-throated Sparrow nests, 52% were parasitized. Black-throated Sparrows appear to respond to natural parasitism by accepting the cowbird egg, deserting the nest, or burying the cowbird egg. Removal and damage of host eggs by female cowbirds effectively reduced clutch size from an average of 3.4 to 1.9 eggs. Because of this reduced clutch size, Black-throated Sparrow reproductive success was significantly lower in parasitized nests (0.2 young fledged/ nest) as compared to nonparasitized nests (1.6 young fledged/nest). When comparing cowbird parasitism between two habitat types, we found significantly higher parasitism frequencies in crucifixion-thorn (Canotia holacantha) versus creosote-bush (Larrea divaricata) habitat. We argue that this difference in parasitism is due to the greater number of tall perches (e.g., shrubs >4 m) available in crucifixion-thorn habitat, providing vantage points for female cowbirds to better find Black-throated Sparrow nests.

  2. UNIVERSITY OF ARIZONA HIGH ENERGY PHYSICS PROGRAM

    Energy Technology Data Exchange (ETDEWEB)

    Rutherfoord, John P. [University of Arizona; Johns, Kenneth A. [University of Arizona; Shupe, Michael A. [University of Arizona; Cheu, Elliott C. [University of Arizona; Varnes, Erich W. [University of Arizona; Dienes, Keith [University of Arizona; Su, Shufang [University of Arizona; Toussaint, William Doug [University of Arizona; Sarcevic, Ina [University of Arizona

    2013-07-29

    The High Energy Physics Group at the University of Arizona has conducted forefront research in elementary particle physics. Our theorists have developed new ideas in lattice QCD, SUSY phenomenology, string theory phenomenology, extra spatial dimensions, dark matter, and neutrino astrophysics. The experimentalists produced significant physics results on the ATLAS experiment at CERN's Large Hadron Collider and on the D0 experiment at the Fermilab Tevatron. In addition, the experimentalists were leaders in detector development and construction, and on service roles in these experiments.

  3. National uranium resource evaluation: Nogales Quadrangle, Arizona

    International Nuclear Information System (INIS)

    Luning, R.H.; Brouillard, L.A.

    1982-04-01

    Literature research, surface geologic investigations, rock sampling, and radiometric surveys were conducted in the Nogales Quadrangle, Arizona, to identify environments and to delineate areas favorable for uranium deposits according to criteria formulated during the National Uranium Resource Evaluation program. The studies were augmented by aerial radiometric and hydrogeochemical and stream-sediment surveys. No favorable environments were identified. Environments that do display favorable characteristics include magmatic-hydrothermal and authigenic environments in Precambrian and Jurassic intrusives, as well as in certain Mesozoic and Cenozoic igneous and sedimentary rocks

  4. Shrub expansion at the forest–tundra ecotone: spatial heterogeneity linked to local topography

    International Nuclear Information System (INIS)

    Ropars, P; Boudreau, S

    2012-01-01

    Recent densification of shrub cover is now documented in many Arctic regions. However, most studies focus on global scale responses, yielding very little information on the local patterns. This research aims to quantify shrub cover increase at northern treeline (Québec, Canada) in two important types of environment, sandy terraces and hilltops (which cover about 70% of the landscape), and to identify the species involved. The comparison of a mosaic of two aerial photographs from 1957 (137 km 2 ) and one satellite image taken in 2008 (151 km 2 ) revealed that both hilltops and terraces recorded an increase in shrub cover. However, the increase was significantly greater on terraces than on hilltops (21.6% versus 11.6%). According to ground truthing, the shrub cover densification is associated mainly with an increase of Betula glandulosa Michx. The numerous seedlings observed during the ground truthing suggest that shrub densification should continue in the future. (letter)

  5. Throughfall and its spatial variability beneath xerophytic shrub canopies within water-limited arid desert ecosystems

    Science.gov (United States)

    Zhang, Ya-feng; Wang, Xin-ping; Hu, Rui; Pan, Yan-xia

    2016-08-01

    Throughfall is known to be a critical component of the hydrological and biogeochemical cycles of forested ecosystems with inherently temporal and spatial variability. Yet little is understood concerning the throughfall variability of shrubs and the associated controlling factors in arid desert ecosystems. Here we systematically investigated the variability of throughfall of two morphological distinct xerophytic shrubs (Caragana korshinskii and Artemisia ordosica) within a re-vegetated arid desert ecosystem, and evaluated the effects of shrub structure and rainfall characteristics on throughfall based on heavily gauged throughfall measurements at the event scale. We found that morphological differences were not sufficient to generate significant difference (P < 0.05) in throughfall between two studied shrub species under the same rainfall and meteorological conditions in our study area, with a throughfall percentage of 69.7% for C. korshinskii and 64.3% for A. ordosica. We also observed a highly variable patchy pattern of throughfall beneath individual shrub canopies, but the spatial patterns appeared to be stable among rainfall events based on time stability analysis. Throughfall linearly increased with the increasing distance from the shrub base for both shrubs, and radial direction beneath shrub canopies had a pronounced impact on throughfall. Throughfall variability, expressed as the coefficient of variation (CV) of throughfall, tended to decline with the increase in rainfall amount, intensity and duration, and stabilized passing a certain threshold. Our findings highlight the great variability of throughfall beneath the canopies of xerophytic shrubs and the time stability of throughfall pattern among rainfall events. The spatially heterogeneous and temporally stable throughfall is expected to generate a dynamic patchy distribution of soil moisture beneath shrub canopies within arid desert ecosystems.

  6. H -Supermagic Labeling on Shrubs Graph and Lm ⨀ Pn

    International Nuclear Information System (INIS)

    Ulfatimah, Risala; Roswitha, Mania; Kusmayadi, Tri Atmojo

    2017-01-01

    A nite simple graph G admits an H -covering if every edge of E ( G ) belongs to a subgraph of G isomorphic to H . We said the graph G = ( V , E ) that admits H -covering to be H -magic if there exists a bijection function f : V ( G ) ∪ E ( G ) → {1, 2, …, | V ( G )| + | E ( G )|} such that for each subgraph H ′ of G isomorphic to H , f ( H ′) = ∑ υ ∈ V ′ f ( υ ) + ∑ e ∈ E ′ f ( e ) = m ( f ) is constant. Furthermore, if f ( V ) = 1, 2, …, | V ( G )| then G is called H -supermagic. In this research we de ned S 2,2 -supermagic labeling on shrub graph Š ( m 1 , m 2 , …, m n ) and fish-supermagic labeling on L m ⨀ P n for m , n ≥ 2. (paper)

  7. 78 FR 21412 - Notice of Intent To Repatriate a Cultural Item: Arizona State Museum, University of Arizona...

    Science.gov (United States)

    2013-04-10

    ..., has determined that the cultural item listed in this notice meets the definition of unassociated... the control of the Arizona State Museum, University of Arizona, Tucson, AZ, that meets the definition... material culture are consistent with the Hohokam archaeological tradition and indicate occupation between...

  8. Volatile diterpene emission by two Mediterranean Cistaceae shrubs.

    Science.gov (United States)

    Yáñez-Serrano, A M; Fasbender, L; Kreuzwieser, J; Dubbert, D; Haberstroh, S; Lobo-do-Vale, R; Caldeira, M C; Werner, C

    2018-05-01

    Mediterranean vegetation emits a wide range of biogenic volatile organic compounds (BVOCs) among which isoprenoids present quantitatively the most important compound class. Here, we investigated the isoprenoid emission from two Mediterranean Cistaceae shrubs, Halimium halimifolium and Cistus ladanifer, under controlled and natural conditions, respectively. For the first time, diurnal emission patterns of the diterpene kaurene were detected in real-time by Proton-Transfer-Reaction-Time-of-Flight-Mass-Spectrometer. Kaurene emissions were strongly variable among H. halimifolium plants, ranging from 0.01 ± 0.003 to 0.06 ± 0.01 nmol m -2 s -1 in low and high emitting individuals, respectively. They were in the same order of magnitude as monoterpene (0.01 ± 0.01 to 0.11 ± 0.04 nmol m -2 s -1 ) and sesquiterpene (0.01 ± 0.01 to 0.52 nmol m -2 s -1 ) emission rates. Comparable range and variability was found for C. ladanifer under natural conditions. Labelling with 13 C-pyruvate suggested that emitted kaurene was not derived from de novo biosynthesis. The high kaurene content in leaves, the weak relationship with ecophysiological parameters and the tendency of higher emissions with increasing temperatures in the field indicate an emission from storage pools. This study highlights significant emissions of kaurene from two Mediterranean shrub species, indicating that the release of diterpenes into the atmosphere should probably deserve more attention in the future.

  9. Local biotic adaptation of trees and shrubs to plant neighbors

    Science.gov (United States)

    Grady, Kevin C.; Wood, Troy E.; Kolb, Thomas E.; Hersch-Green, Erika; Shuster, Stephen M.; Gehring, Catherine A.; Hart, Stephen C.; Allan, Gerard J.; Whitham, Thomas G.

    2017-01-01

    Natural selection as a result of plant–plant interactions can lead to local biotic adaptation. This may occur where species frequently interact and compete intensely for resources limiting growth, survival, and reproduction. Selection is demonstrated by comparing a genotype interacting with con- or hetero-specific sympatric neighbor genotypes with a shared site-level history (derived from the same source location), to the same genotype interacting with foreign neighbor genotypes (from different sources). Better genotype performance in sympatric than allopatric neighborhoods provides evidence of local biotic adaptation. This pattern might be explained by selection to avoid competition by shifting resource niches (differentiation) or by interactions benefitting one or more members (facilitation). We tested for local biotic adaptation among two riparian trees, Populus fremontii and Salix gooddingii, and the shrub Salix exigua by transplanting replicated genotypes from multiple source locations to a 17 000 tree common garden with sympatric and allopatric treatments along the Colorado River in California. Three major patterns were observed: 1) across species, 62 of 88 genotypes grew faster with sympatric neighbors than allopatric neighbors; 2) these growth rates, on an individual tree basis, were 44, 15 and 33% higher in sympatric than allopatric treatments for P. fremontii, S. exigua and S. gooddingii, respectively, and; 3) survivorship was higher in sympatric treatments for P. fremontiiand S. exigua. These results support the view that fitness of foundation species supporting diverse communities and dominating ecosystem processes is determined by adaptive interactions among multiple plant species with the outcome that performance depends on the genetic identity of plant neighbors. The occurrence of evolution in a plant-community context for trees and shrubs builds on ecological evolutionary research that has demonstrated co-evolution among herbaceous taxa, and

  10. Does fire severity influence shrub resprouting after spring prescribed burning?

    Science.gov (United States)

    Fernández, Cristina; Vega, José A.; Fonturbel, Teresa

    2013-04-01

    Prescribed burning is commonly used to reduce the risk of severe wildfire. However, further information about the associated environmental effects is required to help forest managers select the most appropriate treatment. To address this question, we evaluated if fire severity during spring prescribed burning significantly affects the resprouting ability of two common shrub species in shrubland under a Mediterranean climate in NW Spain. Fire behaviour and temperatures were recorded in tagged individuals of Erica australis and Pterospartum tridentatum during prescribed burning. The number and length of resprouted shoots were measured three times (6, 12 and 18 months) after the prescribed burning. The influence of a series of fire severity indicators on some plant resprouting vigour parameters was tested by canonical correlation analysis. Six months and one year after prescribed burning, soil burn severity (measured by the absolute reduction in depth of the organic soil layer, maximum temperatures in the organic soil layer and the mineral soil surface during burning and the post-fire depth of the organic soil layer) reduced the resprouting vigour of E. australis and P. tridentatum. In contrast, direct measurements of fire effects on plants (minimum branch diameter, duration of temperatures above 300 °C in the shrub crown and fireline intensity) did not affect the post-fire plant vigour. Soil burn severity during spring prescribed burning significantly affected the short-term resprouting vigour in a mixed heathland in Galicia. The lack of effects eighteen months after prescribed burning indicates the high resilience of these species and illustrates the need to conciliate fire prevention and conservation goals.

  11. Arctic Tundra Soils: A Microbial Feast That Shrubs Will Cease

    Science.gov (United States)

    Machmuller, M.; Calderon, F.; Cotrufo, M. F.; Lynch, L.; Paul, E. A.; Wallenstein, M. D.

    2016-12-01

    Rapid climate warming may already be driving rapid decomposition of the vast stocks of carbon in Arctic tundra soils. However, stimulated decomposition may also release nitrogen and support increased plant productivity, potentially counteracting soil carbon losses. At the same time, these two processes interact, with plant derived carbon potentially fueling soil microbes to attack soil organic matter (SOM) to acquire nitrogen- a process known as priming. Thus, differences in the physiology, stoichiometry and microbial interactions among plant species could affect climate-carbon feedbacks. To reconcile these interactive mechanisms, we examined how vegetation type (Betula nana and Eriophorum vaginatum) and fertilization (short-term and long-term) influenced the decomposition of native SOM after labile carbon and nutrient addition. We hypothesized that labile carbon inputs would stimulate the loss of native SOM, but the magnitude of this effect would be indirectly related to soil nitrogen concentrations (e.g. SOM priming would be highest in N-limited soils). We added isotopically enriched (13C) glucose and ammonium nitrate to soils under shrub (B. nana) and tussock (E. vaginatum) vegetation. We found that nitrogen additions stimulated priming only in tussock soils, characterized by lower nutrient concentrations and microbial biomass (p20yrs. Rather, we found that long-term fertilization shifted SOM chemistry towards a greater abundance of recalcitrant SOM, lower microbial biomass, and decreased SOM respiration (p<0.05). Our results suggest that, in the short-term, the magnitude of SOM priming is dependent on vegetation and soil nitrogen concentrations, but this effect may not persist if shrubs increase in abundance under climate warming. Therefore, including nitrogen as a control on SOM decomposition and priming is critical to accurately model the effects of climate change on arctic carbon storage.

  12. Clinical significance of neurocysticercosis in endemic villages

    International Nuclear Information System (INIS)

    García, H.H.; Gilman, R.H.; Tsang, V.C.W.; Gonzalez, A.E.

    1997-01-01

    Cerebral cysticercosis is the main cause of late-onset epilepsy in most developing countries. Data on the neuroepidemiology of cysticercosis in endemic populations is scarce. In an endemic village on the northern coast of Peru, 49 individuals with neurological symptomatology (41 epileptic and 8 non-epileptic) were screened for antibodies to Taenia solium, using a serum electroimmuno transfer blot assay. Fifteen subjects were seropositive, 14 (34%) of those with epilepsy but only one (13%) of those who were non-epileptic. A history of passing proglottides was associated with positive serology. Thirteen of the 15 seropositive individuals underwent cerebral computed tomography; only 7 (54%) were abnormal. A randomly selected sample of 20 pigs from the village was also tested, and 6 (30%) were seropositive. This study demonstrated the importance of cysticercosis in the aetiology of epilepsy in endemic villages and the close relationship between porcine and human infection

  13. September 2013 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2013-09-01

    Full Text Available No abstract available. Article truncated at 150 words. The September Arizona Thoracic Society meeting was held on Wednesday, 9/25/2013 at Shea Hospital beginning at 6:30 PM. There were 13 in attendance representing the pulmonary, critical care, sleep, and pathology communities. After a brief discussion, Gerry Swartzberg was selected as Arizona’s 2014 nominee for Clinician of the Year. There was 1 case presented: Dr. Thomas Colby, pulmonary pathologist from Mayo Clinic Arizona, presented the case of a 67 year old woman with multiple pulmonary nodules. The largest was 1.2 cm CT scan. She had a fine needle aspiration of one of the nodules. The pathology revealed spindle-shaped cells which were synaptophysin + (also known as the major synaptic vesicle protein p38. Synaptophysin marks neuroendocrine tissue and on this basis the patient was diagnosed with multiple carcinoid tumors. Aguayo et al. (1 described six patients with diffuse hyperplasia and dysplasia of pulmonary neuroendocrine cells, multiple carcinoid tumorlets, and peribronchiolar fibrosis …

  14. November 2017 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2017-11-01

    Full Text Available No abstract available. Article truncated after 150 words. The November 2017 Arizona Thoracic Society meeting was held on Wednesday, November 15, 2017 at the HonorHealth Rehabilitation Hospital beginning at 6:30 PM. This was a dinner meeting with a lecture followed by case presentations. There were 15 in attendance representing the pulmonary, critical care, sleep, allergy, infectious disease and radiology communities. At the beginning of the meeting several issues were discussed: 1. CME offered by the Southwest Journal of Pulmonary and Critical Care Medicine (SWJPCC is currently offered to only the Southwest state thoracic societies and the Mayo Clinic. After discussion it was felt that this restriction of access was no longer appropriate and CME credits should be available to all. 2. Efforts continue to obtain CME for the Arizona Thoracic Society meetings. Our Chapter Representative, Dr. Gerry Schwartzberg, is approaching this with the American Thoracic Society. Locally, HonorHealth sent out a survey on CME needs. Members were encouraged …

  15. January 2017 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Wesselius LJ

    2017-02-01

    Full Text Available No abstract available. Article truncated after 150 words. The January 2017 Arizona Thoracic Society meeting was held on Wednesday, January 25, 2017 at the HonorHealth Rehabilitation Hospital beginning at 6:30 PM. This was a dinner meeting (prime rib with case presentations. There was a good attendance representing the pulmonary, critical care, sleep, and radiology communities. There was a discussion of supporting the Tobacco 21 bill which has been introduced into the Arizona State Legislature. There was unanimous support for this bill. Another bill to allow school nurses to administer an albuterol inhaler without a doctor’s prescription was also discussed but the members wanted more information. The new CDC Ventilator-Associated Events (VAE criteria were also discussed. Before endorsing or opposing the this as a measure, the members wished more information. It was decided that a decision on both would be postponed until discussed at the next meeting. Three cases were presented: 1. Dr. Lewis Wesselius from the Mayo Clinic …

  16. October 2012 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2012-10-01

    Full Text Available No abstract available. Article truncated at 150 words. A dinner meeting was held on 10/24/2012 at Scottsdale Shea beginning at 6:30 PM. There were 23 in attendance representing the pulmonary, critical care, sleep, infectious disease, pathology, and radiology communities. An announcement was made that the Colorado Thoracic Society has accepted an invitation to partner with the Arizona and New Mexico Thoracic Societies in the Southwest Journal of Pulmonary and Critical Care Medicine. Discussions continue to be held regarding a combined Arizona Thoracic Society meeting with Tucson either in Casa Grande or electronically. Six cases were presented: Dr. Tim Kuberski, chief of Infectious Disease at Maricopa Medical Center, presented a 48 year old female who had been ill for 2 weeks. A CT of the chest revealed a left lower lobe nodule and a CT of the abdomen showed hydronephrosis and a pelvic mass. Carcinoembryonic antigen (CEA was elevated. All turned out to be coccidioidomycosis on biopsy. CEA decreased …

  17. Shrub growth rate and bark responses to soil warming and nutrient addition – A dendroecological approach in a field experiment

    NARCIS (Netherlands)

    Iturrate-Garcia, Maitane; Heijmans, Monique M.P.D.; Schweingruber, Fritz H.; Maximov, Trofim C.; Niklaus, Pascal A.; Schaepman-Strub, Gabriela

    2017-01-01

    Tundra shrubs are slow-growing species limited by low air temperature and scarce nutrient availability. However, shrub expansion has been widely observed in the Arctic during the last decades and attributed to climate warming. Shift in shrub growth, wood structure and abundance affects the

  18. Arid oil-field restoration: native perennial grasses suppress weeds and erosion, but also suppress native shrubs

    Science.gov (United States)

    1. Long-lived, drought-tolerant shrubs are dominant components of many arid ecosystems, and shrubs provide multiple ecosystem services (e.g., soil stabilization, herbaceous plant facilitation, carbon storage and wildlife habitat). On denuded sites, shrub restoration is hindered by abiotic (erosion ...

  19. Changes in epiphyte communities as the shrub, Acer circinatum, develops and ages

    Science.gov (United States)

    Ruchty, A.M.; Rosso, A.L.

    2001-01-01

    The Pacific Northwest tall shrub Acer circinatum (vine maple) can host diverse and abundant epiphyte communities. A chronosequence approach revealed that these communities gradually shift in composition as the shrub progresses through its life cycle. Different epiphytic life forms occupy different spatial and temporal niches on shrub stems. These life forms generally shift upwards along the shrub stem as the stem ages and develops, in accordance with the similar gradient hypothesis. We postulate the following sequence of events. An initial wave of colonization occurs as new substrate is laid down. Over time, superior competitors gradually engulf and overgrow competitively inferior primary colonizers. Concurrently, shrub stem microclimate changes as shrub stems grow, age, and layer, causing the processes of competition and colonization to shift in favor of different epiphytic life forms during different life stages of the shrub stem. We define four separate shrub stem life stages: life classes 1a??4 describe, respectively, young upright a??whipsa??; vigorous, upright, mature stems; declining stems beginning to bend towards the forest floor; and horizontal, decadent stems. As space on the shrub stem is filled through growth and colonization, interspecific competition intensifies. Successful competitors persist and spread, while poor competitors are increasingly restricted to the stem tips, where interspecific competition is less intense. In these forests, Usnea, green-algal foliose lichens, and moss tufts excel as the primary colonizers and become common on the outer portions of shrub stems over time, as long as the overstory is not too dense. Moss mats are also good primary colonizers, but excel as secondary colonizers, often coming to dominate decadent shrub stems. Although all life forms can be primary colonizers, the remaining forms (cyanolichens, liverworts, and Antitrichia curtipendula) are effective secondary colonizers. Liverworts are also effective

  20. Response of dominant grass and shrub species to water manipulation: an ecophysiological basis for shrub invasion in a Chihuahuan Desert grassland.

    Science.gov (United States)

    Throop, Heather L; Reichmann, Lara G; Sala, Osvaldo E; Archer, Steven R

    2012-06-01

    Increases in woody vegetation and declines in grasses in arid and semi-arid ecosystems have occurred globally since the 1800s, but the mechanisms driving this major land-cover change remain uncertain and controversial. Working in a shrub-encroached grassland in the northern Chihuahuan Desert where grasses and shrubs typically differ in leaf-level nitrogen allocation, photosynthetic pathway, and root distribution, we asked if differences in leaf-level ecophysiology could help explain shrub proliferation. We predicted that the relative performance of grasses and shrubs would vary with soil moisture due to the different morphological and physiological characteristics of the two life-forms. In a 2-year experiment with ambient, reduced, and enhanced precipitation during the monsoon season, respectively, the encroaching C(3) shrub (honey mesquite Prosopis glandulosa) consistently and substantially outperformed the historically dominant C(4) grass (black grama Bouteloua eriopoda) in terms of photosynthetic rates while also maintaining a more favorable leaf water status. These differences persisted across a wide range of soil moisture conditions, across which mesquite photosynthesis was decoupled from leaf water status and moisture in the upper 50 cm of the soil profile. Mesquite's ability to maintain physiologically active leaves for a greater fraction of the growing season than black grama potentially amplifies and extends the importance of physiological differences. These physiological and phenological differences may help account for grass displacement by shrubs in drylands. Furthermore, the greater sensitivity of the grass to low soil moisture suggests that grasslands may be increasingly susceptible to shrub encroachment in the face of the predicted increases in drought intensity and frequency in the desert of the southwestern USA.

  1. Mediterranean shrub vegetation: soil protection vs. water availability

    Science.gov (United States)

    García Estringana, Pablo; Nieves Alonso-Blázquez, M.; Alegre, Alegre; Cerdà, Artemi

    2014-05-01

    Soil Erosion and Land Degradation are closely related to the changes in the vegetation cover (Zhao et al., 2013). Although other factors such as rainfall intensiy or slope (Ziadat and Taimeh, 2013) the plant covers is the main factor that controls the soil erosion (Haregeweyn, 2013). Plant cover is the main factor of soil erosion processes as the vegetation control the infiltration and runoff generation (Cerdà, 1998a; Kargar Chigani et al., 2012). Vegetation cover acts in a complex way in influencing on the one hand on runoff and soil loss and on the other hand on the amount and the way that rainfall reaches the soil surface. In arid and semiarid regions, where erosion is one of the main degradation processes and water is a scant resource, a minimum percentage of vegetation coverage is necessary to protect the soil from erosion, but without compromising the availability of water (Belmonte Serrato and Romero Diaz, 1998). This is mainly controlled by the vegetation distribution (Cerdà, 1997a; Cammeraat et al., 2010; Kakembo et al., 2012). Land abandonment is common in Mediterranean region under extensive land use (Cerdà, 1997b; García-Ruiz, 2010). Abandoned lands typically have a rolling landscape with steep slopes, and are dominated by herbaceous communities that grow on pasture land interspersed by shrubs. Land abandonment use to trigger an increase in soil erosion, but the vegetation recovery reduces the impact of the vegetation. The goal of this work is to assess the effects of different Mediterranean shrub species (Dorycnium pentaphyllum Scop., Medicago strasseri, Colutea arborescens L., Retama sphaerocarpa, L., Pistacia Lentiscus L. and Quercus coccifera L.) on soil protection (runoff and soil losses) and on rainfall reaching soil surface (rainfall partitioning fluxes). To characterize the effects of shrub vegetation and to evaluate their effects on soil protection, two field experiments were carried out. The presence of shrub vegetation reduced runoff by

  2. Trends in soil erosion and woody shrub encroachment in Ngqushwa district, Eastern Cape Province, South Africa.

    Science.gov (United States)

    Manjoro, Munyaradzi; Kakembo, Vincent; Rowntree, Kate M

    2012-03-01

    Woody shrub encroachment severely impacts on the hydrological and erosion response of rangelands and abandoned cultivated lands. These processes have been widely investigated at various spatial scales, using mostly field experimentation. The present study used remote sensing to investigate spatial and temporal patterns of soil erosion and encroachment by a woody shrub species, Pteronia incana, in a catchment in Ngqushwa district, Eastern Cape Province, South Africa between 1998 and 2008. The extreme categories of soil erosion and shrub encroachment were mapped with higher accuracy than the intermediate ones, particularly where lower spatial resolution data were used. The results showed that soil erosion in the worst category increased simultaneously with dense woody shrub encroachment on the hill slopes. This trend is related to the spatial patterning of woody shrub vegetation that increases bare soil patches--leading to runoff connectivity and concentration of overland flow. The major changes in soil erosion and shrub encroachment analysed during the 10-year period took place in the 5-9° slope category and on the concave slope form. Multi-temporal analyses, based on remote sensing, can extend our understanding of the dynamics of soil erosion and woody shrub encroachment. They may help benchmark the processes and assist in upscaling field studies.

  3. Dynamics of Understory Shrub Biomass in Six Young Plantations of Southern Subtropical China

    Directory of Open Access Journals (Sweden)

    Yuanqi Chen

    2017-11-01

    Full Text Available Understory shrubs are an important component of forest ecosystems and drive ecosystem processes, such as ecosystem carbon cycling. However, shrub biomass carbon stocks have rarely been reported, which limits our understanding of ecosystem C stock and cycling. In this study, we evaluated carbon accumulation of shrub species using allometric equations based on height and basal diameter in six subtropical plantations at the age of 1, 3, 4 and 6 years. The results showed that plantation type did not significantly affect the total biomass of shrubs, but it significantly affected the biomass of Rhodomyrtus tomentosa, Ilex asprella, Clerodendrum fortunatum and Baeckea frutescens. The biomass of dominant shrub species R. tomentosa, I. asprella, Gardenia jasminoides and Melastoma candidum increased with stand age, while the biomass of C. fortunatum and B. frutescens decreased. The inconsistent biomass-time patterns of different shrub species may be the primary reason for the altered total shrub biomass in each plantation. Consequently, we proposed that R. tomentosa, I. asprella, G. jasminoides and M. candidum could be preferable for understory carbon accumulation and should be maintained or planted because of their important functions in carbon accumulation and high economic values in the young plantations of southern subtropical China.

  4. Climatic warming strengthens a positive feedback between alpine shrubs and fire.

    Science.gov (United States)

    Camac, James S; Williams, Richard J; Wahren, Carl-Henrik; Hoffmann, Ary A; Vesk, Peter A

    2017-08-01

    Climate change is expected to increase fire activity and woody plant encroachment in arctic and alpine landscapes. However, the extent to which these increases interact to affect the structure, function and composition of alpine ecosystems is largely unknown. Here we use field surveys and experimental manipulations to examine how warming and fire affect recruitment, seedling growth and seedling survival in four dominant Australian alpine shrubs. We found that fire increased establishment of shrub seedlings by as much as 33-fold. Experimental warming also doubled growth rates of tall shrub seedlings and could potentially increase their survival. By contrast, warming had no effect on shrub recruitment, postfire tussock regeneration, or how tussock grass affected shrub seedling growth and survival. These findings indicate that warming, coupled with more frequent or severe fires, will likely result in an increase in the cover and abundance of evergreen shrubs. Given that shrubs are one of the most flammable components in alpine and tundra environments, warming is likely to strengthen an existing feedback between woody species abundance and fire in these ecosystems. © 2017 John Wiley & Sons Ltd.

  5. [Soil moisture dynamics of artificial Caragana microphylla shrubs at different topographical sites in Horqin sandy land].

    Science.gov (United States)

    Huang, Gang; Zhao, Xue-yong; Huang, Ying-xin; Su, Yan-gui

    2009-03-01

    Based on the investigation data of vegetation and soil moisture regime of Caragana microphylla shrubs widely distributed in Horqin sandy land, the spatiotemporal variations of soil moisture regime and soil water storage of artificial sand-fixing C. microphylla shrubs at different topographical sites in the sandy land were studied, and the evapotranspiration was measured by water balance method. The results showed that the soil moisture content of the shrubs was the highest in the lowland of dunes, followed by in the middle, and in the crest of the dunes, and increased with increasing depth. No water stress occurred during the growth season of the shrubs. Soil moisture content of the shrubs was highly related to precipitation event, and the relationship of soil moisture content with precipitation was higher in deep soil layer (50-180 cm) than in shallow soil layer (0-50 cm). The variation coefficient of soil moisture content was also higher in deep layer than in shallow layer. Soil water storage was increasing in the whole growth season of the shrubs, which meant that the accumulation of soil water occurred in this area. The evapotranspiriation of the shrubs occupied above 64% of the precipitation.

  6. [Spatial distribution of aboveground biomass of shrubs in Tianlaochi catchment of the Qilian Mountains].

    Science.gov (United States)

    Liang, Bei; Di, Li; Zhao, Chuan-Yan; Peng, Shou-Zhang; Peng, Huan-Hua; Wang, Chao

    2014-02-01

    This study estimated the spatial distribution of the aboveground biomass of shrubs in the Tianlaochi catchment of Qilian Mountains based on the field survey and remote sensing data. A relationship model of the aboveground biomass and its feasibly measured factors (i. e. , canopy perimeter and plant height) was built. The land use was classified by object-oriented technique with the high resolution image (GeoEye-1) of the study area, and the distribution of shrub coverage was extracted. Then the total aboveground biomass of shrubs in the study area was estimated by the relationship model with the distribution of shrub coverage. The results showed that the aboveground biomass of shrubs in the study area was 1.8 x 10(3) t and the aboveground biomass per unit area was 1598.45 kg x m(-2). The distribution of shrubs mainly was at altitudes of 3000-3700 m, and the aboveground biomass of shrubs on the sunny slope (1.15 x 10(3) t) was higher than that on the shady slope (0.65 x 10(3) t).

  7. Solar energy system performance evaluation: Seasonal report for Elcam Tempe Arizona State University, Tempe, Arizona

    Science.gov (United States)

    1980-01-01

    The solar system, Elcam-Tempe, was designed by Elcam Incorporated, Santa Barbara, California, to supply commercial domestic hot water heating systems to the Agriculture Department residence at Arizona State University. The building is a single story residence located at the agriculture experiment farm of the Arizona State University. The energy system's four modes of operation are described. Electrical energy savings at the site was a net of 5.54 million Btu after the 0.17 million Btu of operating energy required to operate collector loop circulating pump were subtracted. The energy savings due to solar was less than the system's potential. On an average, twice as much hot water could have been used with significant solar energy contribution. The system corrosion and deposits caused by using dissimilar metals in the collector loop was the only problem noted with the Elcam-Tempe system.

  8. Plant-Wide Energy Efficiency Assessment at the Arizona Portland Cement Plant in Rillito, Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Stephen J. Coppinger, P.E.; Bruce Colburn, Ph.D., P.E., CEM

    2007-05-17

    A Department of Energy Plant-wide Assessment was undertaken by Arizona Portland Cement (APC) beginning in May 2005. The assessment was performed at APC’s cement production facility in Rillito, Arizona. The assessment included a compressed air evaluation along with a detailed process audit of plant operations and equipment. The purpose of this Energy Survey was to identify a series of energy cost savings opportunities at the Plant, and provide preliminary cost and savings estimates for the work. The assessment was successful in identifying projects that could provide annual savings of over $2.7 million at an estimated capital cost of $4.3 million. If implemented, these projects could amount to a savings of over 4.9 million kWh/yr and 384,420 MMBtu/year.

  9. Mammalian herbivores confer resilience of Arctic shrub-dominated ecosystems to changing climate.

    Science.gov (United States)

    Kaarlejärvi, Elina; Hoset, Katrine S; Olofsson, Johan

    2015-09-01

    Climate change is resulting in a rapid expansion of shrubs in the Arctic. This expansion has been shown to be reinforced by positive feedbacks, and it could thus set the ecosystem on a trajectory toward an alternate, more productive regime. Herbivores, on the other hand, are known to counteract the effects of simultaneous climate warming on shrub biomass. However, little is known about the impact of herbivores on resilience of these ecosystems, that is, the capacity of a system to absorb disturbance and still remain in the same regime, retaining the same function, structure, and feedbacks. Here, we investigated how herbivores affect resilience of shrub-dominated systems to warming by studying the change of shrub biomass after a cessation of long-term experimental warming in a forest-tundra ecotone. As predicted, warming increased the biomass of shrubs, and in the absence of herbivores, shrub biomass in tundra continued to increase 4 years after cessation of the artificial warming, indicating that positive effects of warming on plant growth may persist even over a subsequent colder period. Herbivores contributed to the resilience of these systems by returning them back to the original low-biomass regime in both forest and tundra habitats. These results support the prediction that higher shrub biomass triggers positive feedbacks on soil processes and microclimate, which enable maintaining the rapid shrub growth even in colder climates. Furthermore, the results show that in our system, herbivores facilitate the resilience of shrub-dominated ecosystems to climate warming. © 2015 John Wiley & Sons Ltd.

  10. Range expansion of moose in arctic Alaska linked to warming and increased shrub habitat

    Science.gov (United States)

    Tape, Ken D.; Gustine, David D.; Reuss, Roger W.; Adams, Layne G.; Clark, Jason A.

    2016-01-01

    Twentieth century warming has increased vegetation productivity and shrub cover across northern tundra and treeline regions, but effects on terrestrial wildlife have not been demonstrated on a comparable scale. During this period, Alaskan moose (Alces alces gigas) extended their range from the boreal forest into tundra riparian shrub habitat; similar extensions have been observed in Canada (A. a. andersoni) and Eurasia (A. a. alces). Northern moose distribution is thought to be limited by forage availability above the snow in late winter, so the observed increase in shrub habitat could be causing the northward moose establishment, but a previous hypothesis suggested that hunting cessation triggered moose establishment. Here, we use recent changes in shrub cover and empirical relationships between shrub height and growing season temperature to estimate available moose habitat in Arctic Alaska c. 1860. We estimate that riparian shrubs were approximately 1.1 m tall c. 1860, greatly reducing the available forage above the snowpack, compared to 2 m tall in 2009. We believe that increases in riparian shrub habitat after 1860 allowed moose to colonize tundra regions of Alaska hundreds of kilometers north and west of previous distribution limits. The northern shift in the distribution of moose, like that of snowshoe hares, has been in response to the spread of their shrub habitat in the Arctic, but at the same time, herbivores have likely had pronounced impacts on the structure and function of these shrub communities. These northward range shifts are a bellwether for other boreal species and their associated predators.

  11. Seed distribution of four co-occurring grasses around Artemisia halodendron shrubs in a sandy habitat

    Science.gov (United States)

    Li, Feng-Rui; Zhao, Wen-Zhi; Kang, Ling-Fen; Liu, Ji-Liang; Huang, Zhi-Gang; Wang, Qi

    2009-05-01

    In a natural population of the perennial semi-shrub Artemisia halodendron in a shifting sandy habitat in the Horqin Desert of eastern Inner Mongolia, six isolated adult A. halodendron individuals of similar canopy size were chosen as target plants. The density of seeds in the top 5 cm soil depth around shrubs was measured using transects aligned to the four main wind directions and at different distances from the shrub base on both the windward and leeward sides. The effects of shrub presence on seed distribution of four co-occurring grasses were examined by linking seed distribution to seed traits. Of the four species, Setaris viridis and Eragrostis pilosa had small but similar seed mass, while Chloris virgata and Aristida adscensionis had large but similar seed mass. The species were grouped into two cohorts: small-seeded vs. large-seeded cohorts, and shrub presence effects on seed distribution of both cohorts were examined. We found marked difference in the seed distribution pattern among species, especially between the small-seeded and large-seeded cohorts. The small-seeded cohort had significantly higher seed accumulation on the windward than the leeward sides in the most and least prevailing wind directions and much higher seed accumulation on the leeward than the windward sides in the second and third most prevailing wind directions, while opposite patterns occurred in the large-seeded cohort. Four species also showed marked variation in the seed distribution pattern among transects and between windward and leeward sides of each transect. This study provided further evidence that shrubs embedded in a matrix of herbaceous plants is a key cause of spatial heterogeneity in seed availability of herbaceous species. However, seed distribution responses to the presence of shrubs will vary with species as well as with wind direction, sampling position (windward vs. leeward sides of the shrub) and distance from the shrub.

  12. Purpose of Introduction as a Predictor of Invasiveness among Introduced Shrubs in Rwanda

    Directory of Open Access Journals (Sweden)

    Jean Leonard Seburanga

    2015-01-01

    Full Text Available The introduced shrub flora in Rwanda was analyzed and the risk of invasion was assessed based on the species’ purposes of introduction. The results showed that more than half of invasive alien shrubs in Rwanda were introduced as ornamentals. They include Agave americana L., Bryophyllum proliferum Bowie ex Hook., Caesalpinia decapetala (Roth Alston, Lantana camara L., and Tithonia diversifolia (Hemsley A. Gray. However, these represented only 3.16% of the total number of introduced ornamental shrubs. At the time when the study was conducted, no introduced food crop had become invasive. Species introduced for purposes other than food or culinary use showed higher likelihood of becoming invasive.

  13. The SMOS Mediterranean Ecosystem L-Band characterisation EXperiment (MELBEX-I) over natural shrubs

    DEFF Research Database (Denmark)

    Cano, Aurelio; Saleh, Kauzar; Wigneron, Jean-Pierre

    2010-01-01

    shrub land, as no data were available over this biome. For that purpose, multi-angular and dual polarimetric measurements (H, V) were obtained by the EMIRAD L-band radiometer from a 14-m tower. Results of this study indicate a small and constant impact of vegetation on the microwave emission of shrub...... land, and L-MEB parameters for shrub land were obtained. In addition, the study highlights the need for calibrating microwave soil roughness, which was found to be constant at the site. Depending on the number of retrieved parameters, soil moisture (SM) near the surface could be estimated with errors...

  14. Endemism in the moss flora of North America.

    Science.gov (United States)

    Carter, Benjamin E; Shaw, Blanka; Shaw, A Jonathan

    2016-04-01

    Identifying regions of high endemism is a critical step toward understanding the mechanisms underlying diversification and establishing conservation priorities. Here, we identified regions of high moss endemism across North America. We also identified lineages that contribute disproportionately to endemism and document the progress of efforts to inventory the endemic flora. To understand the documentation of endemic moss diversity in North America, we tabulated species publication dates to document the progress of species discovery across the continent. We analyzed herbarium specimen data and distribution data from the Flora of North America project to delineate major regions of moss endemism. Finally, we surveyed the literature to assess the importance of intercontinental vs. within-continent diversification for generating endemic species. Three primary regions of endemism were identified and two of these were further divided into a total of nine subregions. Overall endemic richness has two peaks, one in northern California and the Pacific Northwest, and the other in the southern Appalachians. Description of new endemic species has risen steeply over the last few decades, especially in western North America. Among the few studies documenting sister species relationships of endemics, recent diversification appears to have played a larger role in western North America, than in the east. Our understanding of bryophyte endemism continues to grow rapidly. Large continent-wide data sets confirm early views on hotspots of endemic bryophyte richness and indicate a high rate of ongoing species discovery in North America. © 2016 Botanical Society of America.

  15. The Chuar Petroleum System, Arizona and Utah

    Science.gov (United States)

    Lillis, Paul G.

    2016-01-01

    The Neoproterozoic Chuar Group consists of marine mudstone, sandstone and dolomitic strata divided into the Galeros and Kwagunt Formations, and is exposed only in the eastern Grand Canyon, Arizona. Research by the U.S. Geological Survey (USGS) in the late 1980s identified strata within the group to be possible petroleum source rocks, and in particular the Walcott Member of the Kwagunt Formation. Industry interest in a Chuar oil play led to several exploratory wells drilled in the 1990s in southern Utah and northern Arizona to test the overlying Cambrian Tapeats Sandstone reservoir, and confirm the existence of the Chuar in subcrop. USGS geochemical analyses of Tapeats oil shows in two wells have been tentatively correlated to Chuar bitumen extracts. Distribution of the Chuar in the subsurface is poorly constrained with only five well penetrations, but recently published gravity/aeromagnetic interpretations provide further insight into the Chuar subcrop distribution. The Chuar petroleum system was reexamined as part of the USGS Paradox Basin resource assessment in 2011. A map was constructed to delineate the Chuar petroleum system that encompasses the projected Chuar source rock distribution and all oil shows in the Tapeats Sandstone, assuming that the Chuar is the most likely source for such oil shows. Two hypothetical plays were recognized but not assessed: (1) a conventional play with a Chuar source and Tapeats reservoir, and (2) an unconventional play with a Chuar source and reservoir. The conventional play has been discouraging because most surface structures have been tested by drilling with minimal petroleum shows, and there is some evidence that petroleum may have been flushed by CO2 from Tertiary volcanism. The unconventional play is untested and remains promising even though the subcrop distribution of source facies within the Chuar Group is largely unknown.

  16. Watch Out for Your Neighbor: Climbing onto Shrubs Is Related to Risk of Cannibalism in the Scorpion Buthus cf. occitanus.

    Science.gov (United States)

    Sánchez-Piñero, Francisco; Urbano-Tenorio, Fernando

    The distribution and behavior of foraging animals usually imply a balance between resource availability and predation risk. In some predators such as scorpions, cannibalism constitutes an important mortality factor determining their ecology and behavior. Climbing on vegetation by scorpions has been related both to prey availability and to predation (cannibalism) risk. We tested different hypotheses proposed to explain climbing on vegetation by scorpions. We analyzed shrub climbing in Buthus cf. occitanus with regard to the following: a) better suitability of prey size for scorpions foraging on shrubs than on the ground, b) selection of shrub species with higher prey load, c) seasonal variations in prey availability on shrubs, and d) whether or not cannibalism risk on the ground increases the frequency of shrub climbing. Prey availability on shrubs was compared by estimating prey abundance in sticky traps placed in shrubs. A prey sample from shrubs was measured to compare prey size. Scorpions were sampled in six plots (50 m x 10 m) to estimate the proportion of individuals climbing on shrubs. Size difference and distance between individuals and their closest scorpion neighbor were measured to assess cannibalism risk. The results showed that mean prey size was two-fold larger on the ground. Selection of particular shrub species was not related to prey availability. Seasonal variations in the number of scorpions on shrubs were related to the number of active scorpions, but not with fluctuations in prey availability. Size differences between a scorpion and its nearest neighbor were positively related with a higher probability for a scorpion to climb onto a shrub when at a disadvantage, but distance was not significantly related. These results do not support hypotheses explaining shrub climbing based on resource availability. By contrast, our results provide evidence that shrub climbing is related to cannibalism risk.

  17. Assessing effect of rainfall on rate of alien shrub expansion in a ...

    African Journals Online (AJOL)

    Assessing effect of rainfall on rate of alien shrub expansion in a southern African savanna. ... Keywords: aerial photography, invasion, Kyle Game Reserve, Lantana camara, patch dynamics, rainfall variability ... AJOL African Journals Online.

  18. Trees, Shrubs, and Woody Vines of the Bluff Experimental Forest, Warren County, Mississippi

    Science.gov (United States)

    Robert L. Johnson; Elbert L. Little

    1967-01-01

    Nearly 100 species of trees, shrubs, and woody vines grow naturally on the 450-acre Bluff Experimental Forest in west-central Mississippi. This publication lists the plants and provides information on silvical characteristics of the tree species.

  19. Trees and shrubs of the Bartlett Experimental Forest, Carroll County, New Hampshire

    Science.gov (United States)

    Stanley M. Filip; Elbert L., Jr. Little; Elbert L. Little

    1971-01-01

    Sixty-five species of trees and shrubs have been identified as native on the Bartlett Experimental Forest. These species are listed in this paper to provide a record of the woody vegetation of the area.

  20. Permafrost collapse after shrub removal shifts tundra ecosystem to a methane source

    DEFF Research Database (Denmark)

    Nauta, Ake L.; Heijmans, Monique P.D.; Blok, Daan

    2015-01-01

    , including expansion of woody vegetation5,6, in response to changing climate conditions. How such vegetation changes contribute to stabilization or destabilization of the permafrost is unknown. Here we present six years of field observations in a shrub removal experiment at a Siberian tundra site. Removing...... the shrub part of the vegetation initiated thawing of ice-rich permafrost, resulting in collapse of the originally elevated shrub patches into waterlogged depressions within five years. This thaw pond development shifted the plots from a methane sink into a methane source. The results of our field......-emitting wet depressions could become more abundant in the lowland tundra landscape, at the cost of permafrost-stabilizing low shrub vegetation....

  1. The initiation of a tropic shrub specia Psidium guajava

    Directory of Open Access Journals (Sweden)

    Julieta Emilia ROMOCEA

    2008-05-01

    Full Text Available Because this tropical fruit is not so popular in Europe, we sis try he initiation of an tropic shrub of Psidium guajava it was possible to make, using them seeds from the matured fruit of guava. The fruit is originally from Egypt – Alexandria. Those seeds were dry and before using them, they were kept in sterile water few hours, after that it was performed the sterilization process, and they were inoculated in 4 different experimental variants.Because them germination process was start late, after 2 months from inoculation, observations were made to the level of the germinated seeds, didn’t shown any infections, but the best results were noticed only on variant V1 (BM basic medium - MS with BA (1 mg/l + IBA (1 mg/l, where the germination capacity it was more bigger.Finally, we did noticed that after the end of this experiment, the best medium culture for the generation of stemlets with many leaves is V1 and V3, but for the root development only V2 showed a very good result. Kept in good light intensity, humidity and optimal temperature conditions, the experiment showed good results, what made this research possible.

  2. Contrasting ozone sensitivity in related evergreen and deciduous shrubs

    International Nuclear Information System (INIS)

    Calatayud, Vicent; Marco, Francisco; Cervero, Julia; Sanchez-Pena, Gerardo; Sanz, Maria Jose

    2010-01-01

    Plant responses to enhanced ozone levels have been studied in two pairs of evergreen-deciduous species (Pistacia terebinthus vs. P. lentiscus; Viburnum lantana vs. V. tinus) in Open Top Chambers. Ozone induced widespread visible injury, significantly reduced CO 2 assimilation and stomatal conductance (g s ), impaired Rubisco efficiency and regeneration capacity (V c,max, J max ) and altered fluorescence parameters only in the deciduous species. Differences in stomatal conductance could not explain the observed differences in sensitivity. In control plants, deciduous species showed higher superoxide dismutase (SOD) activity than their evergreen counterparts, suggesting metabolic differences that could make them more prone to redox imbalances. Ozone induced increases in SOD and/or peroxidase activities in all the species, but only evergreens were able to cope with the oxidative stress. The relevancy of these results for the effective ozone flux approach and for the current ozone Critical Levels is also discussed. - Mediterranean evergreen shrubs have a constitutively higher capacity to tolerate ozone stress than their deciduous relatives.

  3. Contrasting ozone sensitivity in related evergreen and deciduous shrubs

    Energy Technology Data Exchange (ETDEWEB)

    Calatayud, Vicent, E-mail: vicent@ceam.e [Fundacion CEAM, c/ Charles R. Darwin 14, Parque Tecnologico, 46980 Paterna, Valencia (Spain); Marco, Francisco; Cervero, Julia [Fundacion CEAM, c/ Charles R. Darwin 14, Parque Tecnologico, 46980 Paterna, Valencia (Spain); Sanchez-Pena, Gerardo [SPCAN, Dir. Gral. de Medio Natural y Politica Forestal, Ministerio de Medio Ambiente, y Medio Rural y Marino, Rios Rosas 24, 28003 Madrid (Spain); Sanz, Maria Jose [Fundacion CEAM, c/ Charles R. Darwin 14, Parque Tecnologico, 46980 Paterna, Valencia (Spain)

    2010-12-15

    Plant responses to enhanced ozone levels have been studied in two pairs of evergreen-deciduous species (Pistacia terebinthus vs. P. lentiscus; Viburnum lantana vs. V. tinus) in Open Top Chambers. Ozone induced widespread visible injury, significantly reduced CO{sub 2} assimilation and stomatal conductance (g{sub s}), impaired Rubisco efficiency and regeneration capacity (V{sub c,max,}J{sub max}) and altered fluorescence parameters only in the deciduous species. Differences in stomatal conductance could not explain the observed differences in sensitivity. In control plants, deciduous species showed higher superoxide dismutase (SOD) activity than their evergreen counterparts, suggesting metabolic differences that could make them more prone to redox imbalances. Ozone induced increases in SOD and/or peroxidase activities in all the species, but only evergreens were able to cope with the oxidative stress. The relevancy of these results for the effective ozone flux approach and for the current ozone Critical Levels is also discussed. - Mediterranean evergreen shrubs have a constitutively higher capacity to tolerate ozone stress than their deciduous relatives.

  4. Does NDVI reflect variation in the structural attributes associated with increasing shrub dominance in arctic tundra?

    Energy Technology Data Exchange (ETDEWEB)

    Boelman, Natalie T [Lamont-Doherty Earth Observatory, Columbia University, 61 Route 9W, Palisades, NY 10964 (United States); Gough, Laura; McLaren, Jennie R [Department of Biology, University of Texas at Arlington, Arlington, TX 76019 (United States); Greaves, Heather, E-mail: nboelman@ldeo.columbia.edu [Department of Forest Ecosystems and Society, Oregon State University, 321 Richardson Hall, Corvallis, OR 97331 (United States)

    2011-07-15

    This study explores relationships between the normalized difference vegetation index (NDVI) and structural characteristics associated with deciduous shrub dominance in arctic tundra. Our structural measures of shrub dominance are stature, branch abundance, aerial per cent woody stem cover (deciduous and evergreen species), and per cent deciduous shrub canopy cover. All measurements were taken across a suite of transects that together represent a gradient of deciduous shrub height. The transects include tussock tundra shrub and riparian shrub tundra communities located in the northern foothills of the Brooks Range, in northern Alaska. Plot-level NDVI measurements were made in 2010 during the snow-free period prior to deciduous shrub leaf-out (early June, NDVI{sub pre-leaf}), at the point in the growing season when canopy NDVI has reached half of its maximum growing season value (mid-June, NDVI{sub demi-leaf}) and during the period of maximum leaf-out (late July, NDVI{sub peak-leaf}). We found that: (1) NDVI{sub pre-leaf} is best suited to capturing variation in the per cent woody stem cover, maximum shrub height, and branch abundance, particularly between 10 and 50 cm height in the canopy; (2) NDVI{sub peak-leaf} is best suited to capturing variation in deciduous canopy cover; and (3) NDVI{sub demi-leaf} does not capture variability in any of our measures of shrub dominance. These findings suggest that in situ NDVI measurements made prior to deciduous canopy leaf-out could be used to identify small differences in maximum shrub height, woody stem cover, and branch abundance (particularly between 10 and 50 cm height in the canopy). Because shrubs are increasing in size and regional extent in several regions of the Arctic, investigation into spectrally based tools for monitoring these changes are worthwhile as they provide a first step towards development of remotely sensed techniques for quantifying associated changes in regional carbon cycling, albedo, radiative

  5. Variations in the Sensitivity of Shrub Growth to Climate Change along Arctic Environmental and Biotic Gradients

    Science.gov (United States)

    Beck, P. S. A.; Myers-Smith, I. H.; Elmendorf, S.; Georges, D.

    2015-12-01

    Despite evidence of rapid shrub expansion at many Arctic sites and the profound effects this has on ecosystem structure, biogeochemical cycling, and land-atmosphere feedbacks in the Arctic, the drivers of shrub growth remain poorly understood. The compilation of 41,576 annual shrub growth measurements made around the Arctic, allowed for the first systematic evaluation of the climate sensitivity of Arctic shrub growth, i.e. the strength of the relationship between annual shrub growth and monthly climate variables. The growth measurements were taken on 1821 plants of 25 species at 37 arctic and alpine sites, either as annual ring widths or as stem increments. We evaluated climate sensitivity of shrub growth for each genus-by-site combination in this data set based on the performance and parameters of linear mixed models that used CRU TS3.21 climate data as predictors of shrub growth between 1950 and 2010. 76% of genus-by-site combinations showed climate sensitive growth, but climate-growth relationships varied with soil moisture, species canopy height, and geographic position within the species ranges. Shrubs growing at sites with more soil moisture showed greater climate sensitivity, suggesting that water availability might limit shrub growth if continued warming isn't matched by a steady increase in soil moisture. Tall shrub species growing at their northern range limit were particularly climate sensitive causing climate sensitivity of shrubs to peak at the transition between Low and High Arctic, where carbon storage in permafrost is greatest. Local and regional studies have documented matching spatial and temporal patterns in dendrochronological measurements and satellite observations of vegetation indices both in boreal and Arctic regions. Yet the circumarctic comparison of patterns in dendrochronological and remote sensing data sets yielded poor levels of agreement. In much of the Arctic, steep environmental gradients generate fine spatial patterns of vegetation

  6. [Assemblage effect of ground arthropod community in desert steppe shrubs with different ages].

    Science.gov (United States)

    Liu, Ren-Tao; Zhu, Fan; Chai, Yong-Qing

    2014-01-01

    Taking the 6-, 15-, 24- and 36-year-old Caragana intermedia shrubs in desert steppe as a subject, an investigation on soil properties and ground arthropod community was carried out under the shrub and in the open to probe into the assemblage effect of ground arthropod community in desert steppe shrubs with different ages. The results were as follows: 1) In the 6-year-old shrubland, significant differences were only found in soil physical properties (soil texture, soil moisture and electrical conductivity) between the microhabitats under shrub and in the open. Beginning from the 15-year-old shrubland, however, soil organic matter and nutrition (N, P) increased significantly. 2) A total of 27 groups were captured in the studied sites which dominated by Carabidae, Tenebrionidae and Formicidae. From 6- to 15-year-old shrubland, the number of dominant groups decreased while that of common groups increased for the ground arthropod community under the shrub. From 15- to 24- and 36-year-old shrubland, the difference between the microhabitats under the shrub and in the open decreased firstly, and then increased. Some special groups appeared under the shrub in the 36-year-old shrubland, and dung beetles became dominant. 3) In the 6- and 24-year-old shrublands, there were no significant differences in group richness, abundance, and diversity index between the microhabitats under the shrub and in the open. As for the 15- and 36-year-old shrublands, however, significant differences were observed. 4) The shrub age had a stronger effect on the distribution of ground arthropods living under the shrubs compared to that in the open. The changes in soil texture, pH and electrical conductivity could significantly influence on the distribution of ground arthropods under the shrub, also in the open to some degree. It was suggested that the development of shrubland had strong impact on assemblage effect of ground arthropods, which was closely correlated with the stand age and would

  7. Rapid assessment of endemic bird areas in Michoacan, Mexico

    Science.gov (United States)

    Gilberto Chavez-Leon; Deborah M. Finch

    1999-01-01

    Non-sustainable land use practices in the state of Michoacan, Mexico, have perturbed endemic bird h~bitats for several decades. Endemic birds have a restricted geographic and ecological distribution. This feature makes them suitable to be used as indicators of biological diversity and environmental perturbation. Forty-one Mexican endemic species have been recorded in...

  8. Endemicity of cholera in Nigeria: A mathematical model to ...

    African Journals Online (AJOL)

    The focal point is to investigate the persistent endemic nature of cholera in Nigeria using mathematical model. We found that, there can be no backward bifurcation because there existed only one positive endemic equilibrium. In other words, it is not possible for multiple endemic equilibria to exist if the reproduction number ...

  9. Patterns of distribution and protection status of the endemic ...

    African Journals Online (AJOL)

    1995-06-02

    Jun 2, 1995 ... South Africa contains the majority of southern Africa's endemic mammals and hence is an important ... example of an archaic fauna that has undergone local radia- ... Indeed, only six of South Africa's endemic. R eprodu ced by Sabin et G atew ..... of the endemic flora of this region is renowned (Cowling,.

  10. Linking snake habitat use to nest predation risk in grassland birds: the dangers of shrub cover.

    Science.gov (United States)

    Klug, Page E; Jackrel, Sara L; With, Kimberly A

    2010-03-01

    Extremes in rangeland management, varying from too-frequent fire and intensive grazing to the suppression of both, threaten rangeland ecosystems worldwide. Intensive fire and grazing denude and homogenize vegetation whereas their suppression increases woody cover. Although habitat loss is implicated in grassland bird declines, degradation through intensive management or neglect also decreases breeding habitat and may reduce nesting success through increased rates of nest predation. Snakes are important nest predators, but little is known about how habitat use in snakes relates to predation risk for grassland birds nesting within tallgrass prairie subjected to different grazing and fire frequencies. We evaluated nest survival in the context of habitat used by nesting songbirds and two bird-eating snakes, the eastern yellowbelly racer Coluber constrictor flaviventris and Great Plains ratsnake Pantherophis emoryi. Daily nest survival rates decreased with increasing shrub cover and decreasing vegetation height, which characterize grasslands that have been neglected or intensively managed, respectively. Discriminant function analysis revealed that snake habitats were characterized by higher shrub cover, whereas successful nests were more likely to occur in areas with tall grass and forbs but reduced shrub cover. Because snakes often use shrub habitat, birds nesting in areas with increased shrub cover may be at higher risk of nest predation by snakes in addition to other predators known to use shrub habitat (e.g., mid-sized carnivores and avian predators). Depredated nests also occurred outside the discriminant space of the snakes, indicating that other predators (e.g., ground squirrels Spermophilus spp. and bullsnakes Pituophis catenifer) may be important in areas with denuded cover. Targeted removal of shrubs may increase nest success by minimizing the activity of nest predators attracted to shrub cover.

  11. Scrub-shrub bird habitat associations at multiple spatial scales in beaver meadows in Massachusetts

    Science.gov (United States)

    Chandler, R.B.; King, D.I.; DeStefano, S.

    2009-01-01

    Most scrub-shrub bird species are declining in the northeastern United States, and these declines are largely attributed to regional declines in habitat availability. American Beaver (Castor canadensis; hereafter “beaver”) populations have been increasing in the Northeast in recent decades, and beavers create scrub-shrub habitat through their dam-building and foraging activities. Few systematic studies have been conducted on the value of beaver-modified habitats for scrub-shrub birds, and these data are important for understanding habitat selection of scrub-shrub birds as well as for assessing regional habitat availability for these species. We conducted surveys in 37 beaver meadows in a 2,800-km2 study area in western Massachusetts during 2005 and 2006 to determine the extent to which these beaver-modified habitats are used by scrub-shrub birds, as well as the characteristics of beaver meadows most closely related to bird use. We modeled bird abundance in relation to microhabitat-, patch-, and landscape-context variables while adjusting for survey-specific covariates affecting detectability using N-mixture models. We found that scrub-shrub birds of regional conservation concern occupied these sites and that birds responded differently to microhabitat, patch, and landscape characteristics of beaver meadows. Generally, scrub-shrub birds increased in abundance along a gradient of increasing vegetation complexity, and three species were positively related to patch size. We conclude that these habitats can potentially play an important role in regional conservation of scrub-shrub birds and recommend that conservation priority be given to larger beaver meadows with diverse vegetation structure and composition.

  12. Evaluation for breeding purposes of SO/sub 2/-induced damage to trees and shrubs

    Energy Technology Data Exchange (ETDEWEB)

    Bartkowiak, S; Bialobok, S; Rachwal, L

    1975-01-01

    Experiments were performed to determine the response of trees and shrubs to sulfur dioxide in the vicinity of industrial plants. Studies were carried out in the neighborhood of the factories as well as in exposure chambers in the laboratory. Species investigated were Larix liptolepis, Larix potaninii, Populus simonii, Forsythia intermedia, Ligustrum vulgare, Syringa amurensis and Syringa pekinensis. Injuries ranged from virually undamaged to severe, and there was considerable variation within each genus as well as between individual trees and shrubs.

  13. Interactions between Shrubs and Permafrost in the Torngat Mountains, Northern Labrador, Canada

    Science.gov (United States)

    Lewkowicz, A.; Way, R. G.; Hermanutz, L.; Trant, A.; Siegwart Collier, L.; Whitaker, D.

    2017-12-01

    Discontinuous permafrost is acutely sensitive to climate warming and vegetation dynamics. Shrub height is positively correlated with accumulation of snow in the tundra resulting in warming of the ground in winter, and greater shading and lower surface temperatures in summer. Rapid greening due to climate warming has been observed throughout northeastern Canada and particularly in the coastal mountainous terrain of the Torngat Mountains National Park. Our research examines how this shrubification in the Torngat Mountains is modifying permafrost characteristics using observations which extend over a 100 km south-north transect from the sporadic zone (Saglek, Torr Bay) to where permafrost is widespread (Nakvak Brook, Kangalaksiorvik Lake) and potentially continuous (Komaktorvik River). We use air and ground temperature monitoring, vegetation surveys, dendrochronology, frost probing and electrical resistivity tomography (ERT) to describe the complex interactions between shrub growth, geomorphology, climate and permafrost in a region where climate warming is rapidly altering the landscape. Preliminary analysis of field data shows low resistivity anomalies in the ERT profiles at some sites with thin permafrost, interpreted as unfrozen zones correlated with areas of tall shrubs (Alnus spp., Salix spp. and Betula glandulosa; ranging from prostrate to 2 m). Elsewhere, high resistivities extend to the base of the ERT profiles, indicating thicker permafrost, and no obvious impact of medium to low-prostrate shrubs (Salix spp., Betula glandulosa, Rhododendron spp., and Vaccinium spp.; up to 50 cm). Permafrost is interpreted to be present at most sites with low or prostrate shrubs, except where hydrological conditions favour warmer ground temperatures. We infer that the net impact of increasing shrub heights on the active layer and permafrost depends on antecedent ground temperatures and surficial geology. Increasing shrub heights may cause permafrost degradation at sites where

  14. Uniform shrub growth response to June temperature across the North Slope of Alaska

    Science.gov (United States)

    Ackerman, Daniel E.; Griffin, Daniel; Hobbie, Sarah E.; Popham, Kelly; Jones, Erin; Finlay, Jacques C.

    2018-04-01

    The expansion of woody shrubs in arctic tundra alters many aspects of high-latitude ecosystems, including carbon cycling and wildlife habitat. Dendroecology, the study of annual growth increments in woody plants, has shown promise in revealing how climate and environmental conditions interact with shrub growth to affect these key ecosystem properties. However, a predictive understanding of how shrub growth response to climate varies across the heterogeneous landscape remains elusive. Here we use individual-based mixed effects modeling to analyze 19 624 annual growth ring measurements in the stems of Salix pulchra (Cham.), a rapidly expanding deciduous shrub. Stem samples were collected at six sites throughout the North Slope of Alaska. Sites spanned four landscapes that varied in time since glaciation and hence in soil properties, such as nutrient availability, that we expected would modulate shrub growth response to climate. Ring growth was remarkably coherent among sites and responded positively to mean June temperature. The strength of this climate response varied slightly among glacial landscapes, but in contrast to expectations, this variability was not systematically correlated with landscape age. Additionally, shrubs at all sites exhibited diminishing marginal growth gains in response to increasing temperatures, indicative of alternative growth limiting mechanisms in particularly warm years, such as temperature-induced moisture limitation. Our results reveal a regionally-coherent and robust shrub growth response to early season growing temperature, with local soil properties contributing only a minor influence on shrub growth. Our conclusions strengthen predictions of changes to wildlife habitat and improve the representation of tundra vegetation dynamics in earth systems models in response to future arctic warming.

  15. Shrub encroachment alters sensitivity of soil respiration to temperature and moisture

    Science.gov (United States)

    Cable, Jessica M.; Barron-Gafford, Greg A.; Ogle, Kiona; Pavao-Zuckerman, Mitchell; Scott, Russell L.; Williams, David G.; Huxman, Travis E.

    2012-03-01

    A greater abundance of shrubs in semiarid grasslands affects the spatial patterns of soil temperature, moisture, and litter, resulting in fertile islands with potentially enhanced soil metabolic activity. The goal of this study was to quantify the microsite specificity of soil respiration in a semiarid riparian ecosystem experiencing shrub encroachment. We quantified the response of soil respiration to different microsite conditions created by big mesquite shrubs (near the trunk and the canopy edge), medium-sized mesquite, sacaton bunchgrasses, and open spaces. We hypothesized that soil respiration would be more temperature sensitive and less moisture sensitive and have a greater magnitude in shrub microsites compared with grass and open microsites. Field and incubation soil respiration data were simultaneously analyzed in a Bayesian framework to quantify the microsite-specific temperature and moisture sensitivities and magnitude of respiration. The analysis showed that shrub expansion increases the heterogeneity of respiration. Respiration has greater temperature sensitivity near the shrub canopy edge, and respiration rates are higher overall under big mesquite compared with those of the other microsites. Respiration in the microsites beneath medium-sized mesquites does not behave like a downscaled version of big mesquite microsites. The grass microsites show more similarity to big mesquite microsites than medium-sized shrubs. This study shows there can be a great deal of fine-scale spatial heterogeneity that accompanies shifts in vegetation structure. Such complexity presents a challenge in scaling soil respiration fluxes to the landscape for systems experiencing shrub encroachment, but quantifying this complexity is significantly important in determining overall ecosystem metabolic behavior.

  16. Age distributions of Greenlandic dwarf shrubs support concept of negligible actuarial senescence

    Czech Academy of Sciences Publication Activity Database

    Dahlgren, J. P.; Rizzi, S.; Schweingruber, F. H.; Hellmann, L.; Büntgen, Ulf

    2016-01-01

    Roč. 7, č. 10 (2016), č. článku e01521. ISSN 2150-8925 R&D Projects: GA MŠk(CZ) EE2.3.20.0248 Institutional support: RVO:67179843 Keywords : actuarial senescence * age distribution * age structure * Arctic dwarf shrubs * dendroecology * individual survival * mortality * penalized composite link model * plant aging * shrub demography Subject RIV: EH - Ecology, Behaviour Impact factor: 2.490, year: 2016

  17. Endemics and Pseudo-Endemics in Relation to the Distribution Patterns of Indian Pteridophytes

    Directory of Open Access Journals (Sweden)

    C. R. Fraser-Jenkins

    2008-09-01

    Full Text Available Of c. 530 Pteridophytes reported as endemic to the India in recent decades (about half the total number of c. 950-1000 known Indian species, the great bulk are mistaken, particularly those from the Indo-Himalaya. Only 47 endemic Indian ferns, less than 10% of those reported previously, are accepted here. But this figure includes several that are rather doubtfully endemic, mainly due to unresolved taxonomic doubt, or because they may be expected to occur in adjacent Countries. Thus 8 are taxonomically dubious, requiring further study, and a further 7, all from N.E. India, may possibly be expected elsewhere outside India. The c. 483 mistaken pseudo-endemics arose mainly due to naming of erroneous 'new species' thought to be endemic, or due to not knowing the range of species outside political India, combined with insufficient investigative taxonomic research. In the present paper previous reports of endemics are listed and their status is reappraised along with a new list of accepted endemics. Quite opposite to previous conclusions, the great majority of endemic Indian Pteridophytes are peninsular-Indian to south-Indian ferns (27, plus 5 more taxonomically dubious, with far fewer being N.E. Indian (7, all of which may possibly be expected elsewhere outside India and W. Himalayan (2, plus 1 taxonomically dubious; the floristically Malesian Nicobar Islands have (3, plus 2 more taxonomically dubious. These numbers are only to be expected as N.E. India is an intimate part of the Sino-Himalayan and S.E. Asian flora, connected without barriers to Tibet and China or to Myanmar by two mountain chains, while S. India is more isolated geographically since more ancient times and has a partly Malesian fern-flora. Some details of Indian endemics in relation to phytogeographical elements are given. Endemic species: Huperzia - 1, Selaginella - 9, Isoetes - 1, Osmunda - 1, Arthromeris - 1, Phymatosorus - 1, Oreogrammitis - 2, Trichomanes - 1, Pteris - 1, Cyathea

  18. Shift in soil microbial communities with shrub encroachment in Inner Mongolia grasslands, China

    Science.gov (United States)

    Shen, H.; Li, H.; Zhang, J.; Hu, H.; Chen, L.; Zhu, Y.; Fang, J.

    2017-12-01

    The ongoing expansion of shrub encroachment into grasslands represents a unique form of land cover change. How this process affects soil microbial communities is poorly understood. In this study, we aim to assess the effects of shrub encroachment on soil microbial biomass, abundance and composition by comparing data between shrub patches and neighboring herb patches in shrub-encroached grasslands (SEGs) in Inner Mongolia, China. Fourteen SEG sites from two ecosystem types (typical and desert grasslands) were investigated. The phospholipid fatty acid (PLFA) method was used to analyze the composition and biomass of the soil microbial community. Our results showed that the top-soil microbial biomass and abundances of gram-negative bacteria, arbuscular mycorrhizal fungi, and actinomycetes were significantly higher in shrub patches than in herb patches in both typical and desert grasslands (P fungi to bacteria ratio was significantly higher in shrub patches than in herb patches in desert grassland (P soil microbial communities, which makes the microbial communities toward a fresh organic carbon-based structure. This study highlights the importance of edaphic and climate factors in microbial community shifts in SEGs.

  19. Above- and Belowground Biomass Allocation in Shrub Biomes across the Northeast Tibetan Plateau

    Science.gov (United States)

    Yang, Yuanhe; Yang, Lucun; Zhou, Guoying

    2016-01-01

    Biomass partitioning has been explored across various biomes. However, the strategies of allocation in plants still remain contentious. This study investigated allocation patterns of above- and belowground biomass at the community level, using biomass survey from the Tibetan Plateau. We explored above- and belowground biomass by conducting three consecutive sampling campaigns across shrub biomes on the northeast Tibetan Plateau during 2011–2013. We then documented the above-ground biomass (AGB), below-ground biomass (BGB) and root: shoot ratio (R/S) and the relationships between R/S and environment factors using data from 201 plots surveyed from 67 sites. We further examined relationships between above-ground and below-ground biomass across various shrub types. Our results indicated that the median values of AGB, BGB, and R/S in Tibetan shrub were 1102.55, 874.91 g m-2, and 0.85, respectively. R/S showed significant trend with mean annual precipitation (MAP), while decreased with mean annual temperature (MAT). Reduced major axis analysis indicated that the slope of the log-log relationship between above- and belowground biomass revealed a significant difference from 1.0 over space, supporting the optimal hypothesis. Interestingly, the slopes of the allometric relationship between log AGB and log BGB differed significantly between alpine and desert shrub. Our findings supported the optimal theory of above- and belowground biomass partitioning in Tibetan shrub, while the isometric hypothesis for alpine shrub at the community level. PMID:27119379

  20. Mediterranean shrub diversity and its effect on food intake in goats

    Directory of Open Access Journals (Sweden)

    Tomislav Šarić

    2014-07-01

    Full Text Available Mediterranean ecosystem offers a variety of shrubs that were over long periods of time involved in the evolution of complex plant-animal interactions. Biochemical components of these plants enter different metabolic pathways after digestion and absorption, resulting in development of dietary preferences in browsing animals. Herbivores in general were found to perform better when grazing in a mixed plant community composed of diverse species, and show preferential feeding behaviours for mixed vs single species diet. Our findings demonstrate an asymptotic relationship among Mediterranean shrubs species diversity and their voluntary intake by goats. Shrub biomass intake showed linear increase when number of different shrubs in diet increased from one to three. However, goats did not further increase intake when the number of shrub species increased from four to eight. As the number of shrub species offered increased, goats exhibited more preferential feeding behaviour for Quercus pubescens, Fraxinus ornus, Rubus heteromorphus and Arbutus unedo and decreased the intake of Hedera helix, Juniperus oxycedrus and Helichrysum italicum. This asymptotic relationship indicates that the maintenance of plant species richness in Mediterranean shrublands can overall benefit domestic goat farming, goat’s productive performance, and the conservation of plant biodiversity.

  1. Integration of vessel traits, wood density, and height in angiosperm shrubs and trees.

    Science.gov (United States)

    Martínez-Cabrera, Hugo I; Schenk, H Jochen; Cevallos-Ferriz, Sergio R S; Jones, Cynthia S

    2011-05-01

    Trees and shrubs tend to occupy different niches within and across ecosystems; therefore, traits related to their resource use and life history are expected to differ. Here we analyzed how growth form is related to variation in integration among vessel traits, wood density, and height. We also considered the ecological and evolutionary consequences of such differences. In a sample of 200 woody plant species (65 shrubs and 135 trees) from Argentina, Mexico, and the United States, standardized major axis (SMA) regression, correlation analyses, and ANOVA were used to determine whether relationships among traits differed between growth forms. The influence of phylogenetic relationships was examined with a phylogenetic ANOVA and phylogenetically independent contrasts (PICs). A principal component analysis was conducted to determine whether trees and shrubs occupy different portions of multivariate trait space. Wood density did not differ between shrubs and trees, but there were significant differences in vessel diameter, vessel density, theoretical conductivity, and as expected, height. In addition, relationships between vessel traits and wood density differed between growth forms. Trees showed coordination among vessel traits, wood density, and height, but in shrubs, wood density and vessel traits were independent. These results hold when phylogenetic relationships were considered. In the multivariate analyses, these differences translated as significantly different positions in multivariate trait space occupied by shrubs and trees. Differences in trait integration between growth forms suggest that evolution of growth form in some lineages might be associated with the degree of trait interrelation.

  2. Therapy of endemic goiter and hypothyroidism

    Energy Technology Data Exchange (ETDEWEB)

    Luft, D.

    1983-09-12

    Successful treatment of endemic goitre depends on the correct diagnosis and the comprehension of the pathophysiologic changes as well. Several criteria, e.g. anamnestic data, general clinical condition, local symptoms and signs, certainty of diagnosis, contraindications, rates of success, and side effects, determine the particular form of therapy (suppression with thyroid hormones, surgical resection, radio-iodine). The decision criteria are discussed. Prophylaxis of recurrent goitre with either thyroid hormones or iodine salts is necessary after successful treatment. Some endemic goitres behave like either hyper- or hypothyroidism. Treatment with thyroid hormones of patients with latent hyperthyroidism is senseless and dangerous, whereas other methods of treatment may be applied. An unequivocal indication for treatment exists in patients with latent hypothyroidism accompanied by goitre, but not in all patients without goitre. Hormonal replacement therapy of manifest hypothydroidism is simple, but long term success is not achieved in all patients.

  3. Therapy of endemic goiter and hypothyroidism

    International Nuclear Information System (INIS)

    Luft, D.

    1983-01-01

    Successful treatment of endemic goitre depends on the correct diagnosis and the comprehension of the pathophysiologic changes as well. Several criteria, e.g. anamnestic data, general clinical condition, local symptoms and signs, certainty of diagnosis, contraindications, rates of success, and side effects, determine the particular form of therapy (suppression with thyroid hormones, surgical resection, radio-iodine). The decision criteria are discussed. Prophylaxis of recurrent goitre with either thyroid hormones or iodine salts is necessary after successful treatment. Some endemic goitres behave like either hyper- or hypothyroidism. Treatment with thyroid hormones of patients with latent hyperthyroidism is senseless and dangerous, whereas other methods of treatment may be applied. An unequivocal indication for treatment exists in patients with laent hypothyroidism accompanied by goitre, but not in all patients without goitre. Hormonal replacement therapy of manifest hypothydroidism is simple, but long term success is not achieved in all patients. (orig.) [de

  4. Evaluation of shrub and tree species used for revegetating copper mine wastes in the south-western United States. [Dodonea viscosa (L. ) Jacq. , Baccharis sarothroides Gray, Cerdicium microphyllum Torr. , and Nicotiana glauca Grah

    Energy Technology Data Exchange (ETDEWEB)

    Norem, M A; Day, A D; Ludeke, K L

    1982-12-01

    The revegetation work begun in 1970 at Cyprus Pima Mine, an open pit copper mine south-west of Tucson, Arizona, was evaluated to determine the effects of slope aspect and mining waste material on plant survival and growth. Only one shrub, Dodonea viscosa (L.) Jacq. (hopbush), survived on the east slope. Baccharis sarothroides Gray (desert broom) was prolific on the north aspect. Cerdicium microphyllum Torr. (palo verde) survived best on the east slope and Nicotiana glauca Grah. (desert tobacco) survived only on the north slope. The survival of the other tree species was not affected by slope aspect. Slope exposure did not affect tree size, except for Eucalyptus microtheca Muell. (tiny capsule eucalyptus) which grew larger on the north slope. E. rostrata Schlechtend (red gum eucalyptus) grew taller in overburden than in tailing on the east slope. Differences in soil material within each slope exposure did not significantly affect growth of the other tree species. In semi-arid regions, such as south-western Arizona, even slight differences in available moisture may determine the survival of a plant species in the area. (Refs. 11).

  5. Phenological observations on shrubs to predict weed emergence in turf

    Science.gov (United States)

    Masin, Roberta; Zuin, Maria Clara; Zanin, Giuseppe

    2005-09-01

    Phenology is the study of periodic biological events. If we can find easily recognizable events in common plants that precede or coincide with weed emergences, these plants could be used as indicators. Weed seedlings are usually difficult to detect in turf, so the use of phenological indicators may provide an alternative approach to predict the time when a weed appears and consequently guide management decisions. A study was undertaken to determine whether the phenological phases of some plants could serve as reliable indicators of time of weed emergence in turf. The phenology of six shrubs (Crataegus monogyna Jacq., Forsythia viridissima Lindl., Sambucus nigra L., Syringa vulgaris L., Rosa multiflora Thunb., Ziziphus jujuba Miller) and a perennial herbaceous plant [Cynodon dactylon (L.) Pers.] was observed and the emergence dynamics of four annual weed species [Digitaria sanguinalis (L.) Scop., Eleusine indica (L.) Gaertner, Setaria glauca (L.) Beauv., Setaria viridis (L.) Beauv.] were studied from 1999 to 2004 in northern Italy. A correlation between certain events and weed emergence was verified. S. vulgaris and F. viridissima appear to be the best indicators: there is a quite close correspondence between the appearance of D. sanguinalis and lilac flowering and between the beginning of emergence of E. indica and the end of lilac flowering; emergences of S. glauca and S. viridis were predicted well in relation to the end of forsythia flowering. Base temperatures and starting dates required to calculate the heat unit sums to reach and complete the flowering phase of the indicators were calculated using two different methods and the resultant cumulative growing degree days were compared.

  6. Arizona geothermal institutional handbook: Arizona geothermal commercialization planning team, January 1-December 31, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Malysa, L.

    1980-05-01

    The purpose of this handbook is to assist in understanding the various procedures and requirements necessary for the development of geothermal energy in the State of Arizona. It contains the names of key persons and agencies who are directly or indirectly involved in the institutional process. A detailed assessment of all agencies and the role they play in geothermal energy development is provided. The handbook is divided into four sections: State and Local rules and regulations, the Federal rules and regulations, references, and a technical bibliography. (MHR)

  7. November 2015 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2015-11-01

    Full Text Available No abstract available. Article truncated after 150 words. The November 2015 Arizona Thoracic Society meeting was held on Wednesday, November 18, 2015 at the Scottsdale Shea Hospital beginning at 6:30 PM. This was a dinner meeting with case presentations. There were 14 in attendance representing the pulmonary, critical care, sleep, and radiology communities. There were 3 case presentations: 1. Dr. Gerald Schwartzberg presented a case of a 56-year-old man with a history of diabetes, alcoholism and tobacco abuse who has a history of Mycobacterium avium-intracellulare (MAI with a residual thin-walled cavity in his right upper lobe (RUL. After quitting drinking and smoking and years of being asymptomatic, he presented with hemoptysis. Chest x-ray showed increasing density in the RUL. CT scan showed an intracavitary density in his previous cavity presumably a fungus ball. Sputum cultures are pending. Discussion followed on management of fungus balls. Bronchoscopy was recommended to view the bronchial anatomy to exclude other diagnosis as well ...

  8. Active mines in Arizona - 1993. Directory 40

    International Nuclear Information System (INIS)

    Phillips, K.A.; Niemuth, N.J.; Bain, D.R.

    1992-01-01

    A directory of the active mines in Arizona is presented. The directory was compiled in November, 1992 from field visits and information received by the Department's technical staff. For the purpose of this directory, an active mine is defined as a mine in continuous operation, either in production or under full-time development for production. Custom milling operations that are active or available on a full-time basis are also included in the directory. It is acknowledged that there are additional mines not listed that are in an exploration, evaluation, or part-time development phase. There are others where production is on an intermittent basis that are not listed. The report is dependent on the cooperation of government agencies, private industry, and individuals who voluntarily provide information on their projects and activities. The directory is arranged alphabetically by company name. Each listing includes corporate addresses, mine name and location, operation description, and key personnel. The listing for the sand and gravel operations include name, address, and phone number

  9. Crotalid envenomation: the southern Arizona experience.

    Science.gov (United States)

    Tokish, J T; Benjamin, J; Walter, F

    2001-01-01

    To review a regional experience with the treatment of snakebites. Five major southern Arizona hospitals, including two Level I trauma centers. A review of all snakebite admissions over a five-year period was performed. During the period reviewed, 164 patients were admitted for snakebites. Rattlesnakes were responsible for 98 percent of identified envenomations. Thirty-six percent of the patients were transported by air to the admitting facility. Eighty percent of patients were admitted to the intensive care unit for an average of 1.6 days. Total hospital stays averaged 2.8 days. Ninety percent of patients received antivenin, usually only on the day of admission. Of those receiving antivenin, 20 percent had an anaphylactoid reaction, and 1 percent required readmission for serum sickness. Laboratory evaluation indicated abnormalities in platelet count, coagulation parameters, and fibrinogen levels, but these rarely required treatment. Thirteen percent of patients underwent surgical intervention, including a 4 percent fasciotomy rate, and a single amputation. The use of field treatment, including "cut and suck," tourniquets, and cryotherapy, increased the likelihood of surgery. The authors concluded that the intensive care unit and helicopter transport system were overused. They recommend that established objective envenomation severity scores be used to dictate patient treatment, specifically the use of antivenin.

  10. National uranium resource evaluation: Williams quadrangle, Arizona

    International Nuclear Information System (INIS)

    O'Neill, A.J.; Nystrom, R.J.; Thiede, D.S.

    1981-03-01

    Geologic environments of the Williams Quadrangle, Arizona, were evaluated for uranium favorability by means of literature research, uranium-occurrence investigation and other surface studies, subsurface studies, aerial radiometric data, hydrogeochemical data, and rock-sample analytic data. Favorability criteria are those of the National Uranium Resource Evaluation program. Three geologic environments are favorable for uranium: the Tertiary fluvial rocks of the Colorado Plateau where they unconformably overlie impermeable bed rock (for channel-controlled peneconcordant deposits); collapse breccia pipes in Paleozoic strata of the Colorado Plateau (for vein-type deposits in sedimentary rocks); and Precambrian crystalline rocks of the Hualapai, Peacock, and Aquarius Mountains, and Cottonwood and Grand Wash Cliffs (for magmatic-hydrothermal deposits). Unfavorable geologic environments are: Tertiary and Quaternary volcanic rocks, Tertiary and Quaternary sedimentary rocks of the Colorado Plateau, nearly all Paleozoic and Mesozoic sedimentary rocks, and the Precambrian-Cambrian unconformity of the Grand Wash Cliffs area. Tertiary rocks in Cenozoic basins and Precambrian crystalline rocks in the Grand Canyon region and in parts of the Aquarius Mountains and Cottonwood and Grand Wash Cliffs are unevaluated

  11. October 2013 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2013-10-01

    Full Text Available No abstract available. Article truncated after 150 words. The October Arizona Thoracic Society meeting was held on Wednesday, 10/23/2013 at Shea Hospital beginning at 6:30 PM. There were 21 in attendance representing the pulmonary, critical care, sleep, and thoracic surgery communities. A proposal was made to decrease the number of meetings from 10 to 8 per year. After a brief discussion, this was adopted. Dr. Parides will try and coordinate these changes with Tucson. Meetings were announced for December in Tucson, January in Carmel, February in Albuquerque, and April in Phoenix. A suggestion was made to have a separate area for meetings on the SWJPCC website. There were 2 cases presented-both by Nick Sparacino, a first year fellow at Good Samaritan/VA. 1. The first case was a 48 year old man admitted to podiatry for chronic diabetic foot ulcers. His preoperative chest x-ray revealed multiple pulmonary nodules. Importantly, he had a history of working in a brake pad …

  12. Causes of sinks near Tucson, Arizona, USA

    Science.gov (United States)

    Hoffmann, J.P.; Pool, D.R.; Konieczki, A.D.; Carpenter, M.C.

    1998-01-01

    Land subsidence in the form of sinks has occurred on and near farmlands near Tucson, Pima County, Arizona, USA. The sinks occur in alluvial deposits along the flood plain of the Santa Cruz River, and have made farmlands dangerous and unsuitable for farming. More than 1700 sinks are confined to the flood plain of the Santa Cruz River and are grouped along two north-northwestward-trending bands that are approximately parallel to the river and other flood-plain drainages. An estimated 17,000 m3 of sediment have been removed in the formation of the sinks. Thirteen trenches were dug to depths of 4-6 m to characterize near-surface sediments in sink and nonsink areas. Sediments below about 2 m included a large percentage of dispersive clays in sink areas. Sediments in nonsink areas contain a large component of medium- to coarse-grained, moderately to well sorted sand that probably fills a paleochannel. Electromagnetic surveys support the association of silts and clays in sink areas that are highly electrically conductive relative to sand in nonsink areas. Sinks probably are caused by the near-surface process of subsurface erosion of dispersive sediments along pre-existing cracks in predominantly silt and clay sediments. The pre-existing cracks probably result from desiccation or tension that developed during periods of water-table decline and channel incision during the past 100 years or in earlier periods.

  13. July 2016 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2016-07-01

    Full Text Available No abstract available. Article truncated after first 150 words. The July 2016 Arizona Thoracic Society meeting was held on Wednesday, July 27, 2016 at the Scottsdale Shea Hospital beginning at 6:30 PM. This was a dinner meeting with case presentations. There were 14 in attendance representing the pulmonary, critical care, sleep, and radiology communities. Prior to the case presentations, a discussion was held on 4 issues. First, Dr. Rick Robbins gave a summary of ATS Hill Day. During Hill Day a presentation was given by a representative from the Campaign for Tobacco-Free Kids. Their web site lists tobacco company contributions to members of Congress on their web site. Dr. Gary Ewart from the ATS office in Washington gave a presentation on the Traditional Cigar Manufacturing and Small Business Jobs Preservation Act before Congress (aka the Cigar Bill which the ATS opposes. He noted that cosponsors for the bill included several Congressmen from Southwestern states. Dr. Robbins combined the two ...

  14. September 2012 Arizona thoracic society notes

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2012-09-01

    Full Text Available No abstract available. Article truncated at 150 words. A dinner meeting was held on 9/26//2012 at Scottsdale Shea beginning at 6:30 PM. There were 18 in attendance representing the pulmonary, critical care, sleep, pathology, and radiology communities.A discussion was held on Pending Premium Cigar Legislation HR. 1639 and S.1461, the "Traditional Cigar Manufacturing and Small Business Jobs Preservation Act of 2011”. This bill would exempt "premium cigars" from FDA oversight. The definition of premium cigars is so broad that candy flavored cigars, cigarillos and blunts would be exempted from FDA regulation. Teenage cigar smoking is increasing and this legislation may result in a further increase. The Arizona Thoracic Society is opposed to this bill. Dr. Robbins is to put a link on the Southwest Journal of Pulmonary and Critical Care website linking to the ATS website. This will enable members to contact their Congressmen opposing this legislation. A discussion was also held on a proposed combined Tucson/Phoenix …

  15. Isotopic paleoecology of Clovis mammoths from Arizona

    Science.gov (United States)

    Metcalfe, Jessica Z.; Longstaffe, Fred J.; Ballenger, Jesse A. M.; Vance Haynes, C., Jr.

    2011-11-01

    The causes of megafaunal extinctions in North America have been widely debated but remain poorly understood. Mammoths (Mammuthus spp.) in the American Southwest were hunted by Clovis people during a period of rapid climate change, just before the regional onset of Younger Dryas cooling and mammoth extirpation. Thus, these mammoths may provide key insights into late Pleistocene extinction processes. Here we reconstruct the seasonal diet and climatic conditions experienced by mammoths in the San Pedro Valley of Arizona, using the carbon (13C/12C) and oxygen (18O/16O) isotope compositions of tooth enamel. These records suggest that Clovis mammoths experienced a warm, dry climate with sufficient summer rainfall to support seasonal C4 plant growth. Monsoon intensity may have been reduced relative to the preceding time period, but there is no isotopic evidence for severe drought. However, it is possible that the "Clovis drought", inferred from stratigraphic evidence, occurred suddenly at the end of the animals' lives and thus was not recorded in the enamel isotopic compositions. Unlike mammoths that lived before the Last Glacial Maximum, Clovis mammoths regularly increased C4 grass consumption during summer, probably seeking seasonally green grasslands farther from the river valley. This predictable seasonal behavior may have made mammoths easier to locate by Clovis hunters. Furthermore, Clovis mammoths probably had no previous experience of such sudden climatic change as is believed to have occurred at the time of their extinction.

  16. Ground biomass assessment of shrub species in tehsil takht-e-nasrati, pakistan

    International Nuclear Information System (INIS)

    Khan, M.; Hussain, F.; Musharaf, S.; Musharaf, S.

    2014-01-01

    The shrub biomass of different species of Tehsil Takht-e-Nasrati was different at different altitude. In the present study it was found that the average shrub biomass was decreasing with increasing altitude. Result confirms that the biomass of Saccharum bengalense was high 5020.38 Kg.hec/sup -1/ in phase 1 and phase 2 (4331.58 Kg.hec/sup -1/). The highest ground biomass 1125.1 Kg.hec/sup -1/ of Zizyphus nummularia was found in Phase 3. Furthermore in Phase 4 the biomass of Capparis deciduas was high 437.79 Kg.hec/sup -1/. Along with shrubs average biomass of Saccharum bengalense was high 2665.12 Kg.hec/sup -1/ and low 13.47 Kg.hec/sup -1/ of Cassia angustifolia. With seasons the biomass of Saccharum bengalense (13800 Kg.hec/sup -1/) was greater during winter at Phase 1 and Periploc aaphylla (12.35 Kg.hec-1) biomass was lowers during spring at Phase 4. In comparison in season the biomass was high in winter due to the dormant stage of shrubs in phase 1 while it was low in summer in phase 4. In winter the grazing process was stop due to agriculture point of view while in hilly area the grazing was high and the low percentage of rain fall consequently the biomass was high in plain area as contrast to hilly area. The biomass of shrubs is high in winter while it was low in summer as the grazing and palatability rate was high in summer as well as low in winter. The assessment of shrub biomass in research area is a requirement for successful management at the same time as it gives a complete documentation for the area in complexity and work out unpredictable resources to help imagine shrubs potency and behavior. (author)

  17. Home Water Treatment Habits and Effectiveness in a Rural Arizona Community.

    Science.gov (United States)

    Lothrop, Nathan; Wilkinson, Sarah T; Verhougstraete, Marc; Sugeng, Anastasia; Loh, Miranda M; Klimecki, Walter; Beamer, Paloma I

    Drinking water quality in the United States (US) is among the safest in the world. However, many residents, often in rural areas, rely on unregulated private wells or small municipal utilities for water needs. These utilities may violate the Safe Drinking Water Act contaminant guidelines, often because they lack the required financial resources. Residents may use alternative water sources or install a home water treatment system. Despite increased home water treatment adoption, few studies have examined their use and effectiveness in the US. Our study addresses this knowledge gap by examining home water treatment in a rural Arizona community. Water samples were analyzed for metal(loid)s, and home treatment and demographic data were recorded in 31 homes. Approximately 42% of homes treated their water. Independent of source water quality, residents with higher income (OR = 1.25; 95%CI (1.00 - 1.64)) and education levels (OR = 1.49; 95%CI (1.12 - 2.12)) were more likely to treat their water. Some contaminant concentrations were effectively reduced with treatment, while some were not. We conclude that increased educational outreach on contaminant testing and treatment, especially to rural areas with endemic water contamination, would result in a greater public health impact while reducing rural health disparities.

  18. 78 FR 48326 - Partial Disapproval of State Implementation Plan; Arizona; Regional Haze Requirements

    Science.gov (United States)

    2013-08-08

    ... Disapproval of State Implementation Plan; Arizona; Regional Haze Requirements AGENCY: Environmental Protection... behalf of National Parks Conservation Association, Sierra Club, Physicians for Social Responsibility... Haze State Implementation Plan Revision submitted by the Arizona Department of Environmental Quality on...

  19. Cost-Effectiveness Analysis of the Residential Provisions of the 2015 IECC for Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Mendon, Vrushali V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zhao, Mingjie [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Taylor, Zachary T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Poehlman, Eric A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-02-15

    The 2015 IECC provides cost-effective savings for residential buildings in Arizona. Moving to the 2015 IECC from the 2009 IECC base code is cost-effective for residential buildings in all climate zones in Arizona.

  20. Effect of supplementation with barley and calcium hydroxide on intake of Mediterranean shrubs

    Directory of Open Access Journals (Sweden)

    Dragan Skobic

    2011-04-01

    Full Text Available Maquis plant communities are one of the most varied vegetation types in the Mediterranean region and an important habitat for wild and domestic herbivores. Although the majority of these shrubs are nutritious, the secondary compounds are main impediments that reduce their forage value. In five experiments we determined the effect of supplementing goats with calcium hydroxide plus barley, and barley alone on intake of five dominant shrubs (Quercus ilex, Erica multiflora, Arbutus unedo, Viburnum tinus and Pistacia lentiscus of the Mediterranean maquis community. The combination of calcium hydroxide plus barley and barley alone increased utilization of all five investigated Mediterranean shrubs; therewith that intake of Arbutus unedo and Viburnum tinus was not statistically significant. Supplemented goats with calcium hydroxide plus barley or barley alone could be effective in controlling secondary compounds-rich Mediterranean shrubs where their abundance threatens biodiversity. This control can be facilitated by browsing dominant Mediterranean shrubs, which has been shown to be effective in managing Mediterranean maquis density. Calcium hydroxide and barley (energy enhance use of secondary compounds-containing plants, which may increase production of alternate forages and create a more diverse mix of plant species in the Mediterranean maquis plant community.

  1. Electrostatic Interactions between Elongated Monomers Drive Filamentation of Drosophila Shrub, a Metazoan ESCRT-III Protein

    Directory of Open Access Journals (Sweden)

    Brian J. McMillan

    2016-08-01

    Full Text Available The endosomal sorting complex required for transport (ESCRT is a conserved protein complex that facilitates budding and fission of membranes. It executes a key step in many cellular events, including cytokinesis and multi-vesicular body formation. The ESCRT-III protein Shrub in flies, or its homologs in yeast (Snf7 or humans (CHMP4B, is a critical polymerizing component of ESCRT-III needed to effect membrane fission. We report the structural basis for polymerization of Shrub and define a minimal region required for filament formation. The X-ray structure of the Shrub core shows that individual monomers in the lattice interact in a staggered arrangement using complementary electrostatic surfaces. Mutations that disrupt interface salt bridges interfere with Shrub polymerization and function. Despite substantial sequence divergence and differences in packing interactions, the arrangement of Shrub subunits in the polymer resembles that of Snf7 and other family homologs, suggesting that this intermolecular packing mechanism is shared among ESCRT-III proteins.

  2. [Rainfall and soil moisture redistribution induced by xerophytic shrubs in an arid desert ecosystem].

    Science.gov (United States)

    Wang, Zheng Ning; Wang, Xin Ping; Liu, Bo

    2016-03-01

    Rainfall partitioning by desert shrub canopy modifies the redistribution of incident rainfall under the canopy, and may affect the distribution pattern of soil moisture around the plant. This study examined the distribution of rainfall and the response of soil moisture beneath the canopy of two dominant desert shrubs, Caragana korshinskii and Artemisia ordosica, in the revegetation area at the southeastern edge of the Tengger Desert. The results showed that throughfall and stemflow ave-ragely occupied 74.4%, 11.3% and 61.8%, 5.5% of the gross precipitation for C. korshinskii and A. ordosica, respectively. The mean coefficients of variation (CV) of throughfall were 0.25 and 0.30, respectively. C. korshinski were more efficient than A. ordosica on stemflow generation. The depth of soil wetting front around the stem area was greater than other areas under shrub canopy for C. korshinski, and it was only significantly greater under bigger rain events for A. ordosica. The shrub canopy could cause the unevenness of soil wetting front under the canopy in consequence of rainfall redistribution induced by xerophytic shrub.

  3. [Effects of target tree tending on community structure and diversity in subtropical natural secondary shrubs].

    Science.gov (United States)

    Zhang, Hui; Zhou, Guo Mo; Bai, Shang Bin; Wang, Yi Xiang; You, Yu Jie; Zhu, Ting Ting; Zhang, Hua Feng

    2017-05-18

    The typical natural secondary shrub community was chosen in Lin'an of Zhejiang Pro-vince to discover its possibility of restoration to arbor forest with three kinds of forest management models being taken, i.e., no care as control, closed forest management and target tree tending. Over four years growth, compared with control, closed forest management significantly increased average DBH and height by 130% and 50%, respectively, while 260% and 110% for target tree tending. In target tree tending plots, larger trees had been emerging with 4.5-8.5 cm diameter class and 4.5-8.5 m height class and formed a new storey of 4 m compared with control. The species biodiversity indexes at shrub layer were significantly increased in closed management plots, and did not decrease in target tree tending plots. Closed forest management did not change the tree species composition, following its previous succession direction. However, target tree tending increased the importance value of target species with the high potential succession direction of mixed coniferous-broadleaved forest. The results revealed that the secondary shrub community with target tree tending achieved more desired goals on DBH and height growth of dominant trees and species composition improvement compared with closed management. If the secondary shrub community could be managed when the operational conditions existed, target tree tending model should be selected to accelerate the restoration of shrub toward arbor forest.

  4. Bioactive Secondary Metabolites from Schizogyne sericea (Asteraceae) Endemic to Canary Islands.

    Science.gov (United States)

    Venditti, Alessandro; Bianco, Armandodoriano; Muscolo, Camilla; Zorzetto, Christian; Sánchez-Mateo, Candelaria C; Rabanal, Rosa M; Quassinti, Luana; Bramucci, Massimo; Damiano, Silvia; Iannarelli, Romilde; Lupidi, Giulio; Papa, Fabrizio; Petrelli, Dezemona; Vitali, Luca A; Vittori, Sauro; Maggi, Filippo

    2016-07-01

    Schizogyne sericea (Asteraceae) is a halophytic shrub endemic to the Canary Islands and traditionally employed as analgesic, astringent, anti-inflammatory, and vulnerary. A comprehensive phytochemical investigation was conducted on the flowering aerial parts by analyzing both essential oil constituents and polar compounds. The essential oil was dominated by p-cymene, with the noteworthy occurrence of β-pinene and thymol esters. From the EtOH extract, eight compounds were isolated and structurally elucidated. Essential oil, polar fractions, and isolates (2), (4), and (5) were separately in vitro assayed for antiproliferative activity on human tumor cell lines (A375, MDA-MB 231, and HCT116) by MTT assay, for antioxidant potential by DPPH, ABTS, and FRAP assays, and for antimicrobial activity by the agar disk diffusion method. Results revealed that essential oil and compounds 1 and 2 exert a strong inhibition on tumor cells, and in some cases, higher than that of cisplatin. Fractions containing thymol derivatives (1 and 2) and caffeoylquinic acid derivatives 4 and 5 displayed antioxidant activity comparable to that of Trolox, making S. sericea extract an interesting natural product with potential applications as preservative or in the treatment of diseases in which oxidative stress plays an important role. © 2016 Wiley-VHCA AG, Zürich.

  5. Integrated solid waste management of Scottsdale, Arizona

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-11-01

    The subject document reports the results of an in-depth investigation of the fiscal year 1992 cost of the city of Scottsdale, Arizona, integrated municipal solid waste management (IMSWM) system, the energy consumed to operate the system, and the environmental performance requirements for each of the system`s waste-processing and disposal facilities. The document reports actual data from records kept by participants. Every effort was made to minimize the use of assumptions, and no attempt is made to interpret the data reported. Analytical approaches are documented so that interested analysts may per-form manipulation or further analysis of the data. As such, the report is a reference document for municipal solid waste (MSW) management professionals who are interested in the actual costs and energy consumption, for a 1-year period, of an operating IMSWM system. The report is organized into two main parts. The first part is the executive summary and case study portion of the report. The executive summary provides a basic description of the study area and selected economic and energy information. Within the case study are detailed descriptions of each component operating during the study period; the quantities of solid waste collected, processed, and marketed within the study boundaries; the cost of MSW in Scottsdale; an energy usage analysis; a review of federal, state, and local environmental requirement compliance; a reference section; and a glossary of terms. The second part of the report focuses on a more detailed discourse on the above topics. In addition, the methodology used to determine the economic costs and energy consumption of the system components is found in the second portion of this report. The methodology created for this project will be helpful for those professionals who wish to break out the costs of their own integrated systems.

  6. An Archaeological Sample Survey of the Whitlow Ranch Reservoir, Pinal County, Arizona.

    Science.gov (United States)

    1977-09-01

    in situ Hohokam developme,z. The Salado concept itself may be questioned; Hohokam and Salade cc-stitute similar manifes- tations and the criteria for...Gila Aqueducts, Agua Fria River to Gila River, Arizona. Arizona State University Anthropological Research Paper 1. Forrester, J. D. 1962 Folio of...Weaver, Donald E., Jr. 1974 Archaeological investigations at the Westwing site, AZ T:7:27 (ASU), Agua Fria River Valley, Arizona. Arizona State Univer

  7. Causes of sinks near Tucson, Arizona, USA

    Science.gov (United States)

    Hoffmann, John P.; Pool, Donald R.; Konieczki, A. D.; Carpenter, Michael C.

    Land subsidence in the form of sinks has occurred on and near farmlands near Tucson, Pima County, Arizona, USA. The sinks occur in alluvial deposits along the flood plain of the Santa Cruz River, and have made farmlands dangerous and unsuitable for farming. More than 1700 sinks are confined to the flood plain of the Santa Cruz River and are grouped along two north-northwestward-trending bands that are approximately parallel to the river and other flood-plain drainages. An estimated 17,000m3 of sediment have been removed in the formation of the sinks. Thirteen trenches were dug to depths of 4-6m to characterize near-surface sediments in sink and nonsink areas. Sediments below about 2m included a large percentage of dispersive clays in sink areas. Sediments in nonsink areas contain a large component of medium- to coarse-grained, moderately to well sorted sand that probably fills a paleochannel. Electromagnetic surveys support the association of silts and clays in sink areas that are highly electrically conductive relative to sand in nonsink areas. Sinks probably are caused by the near-surface process of subsurface erosion of dispersive sediments along pre-existing cracks in predominantly silt and clay sediments. The pre-existing cracks probably result from desiccation or tension that developed during periods of water-table decline and channel incision during the past 100 years or in earlier periods. Résumé Des effondrements en forme d'entonnoir se sont produits sur et près d'exploitations agricoles de Pima (Arizona). Ces entonnoirs apparaissent dans les alluvions le long de la plaine d'inondation de la rivière Santa Cruz ; ils ont rendu ces terrains dangereux et inexploitables pour l'agriculture. Plus de 1700 entonnoirs existent dans la plaine d'inondation de la rivière Santa Cruz et sont groupés en deux bandes orientées nord-nord-ouest, approximativement parallèles à la rivière et aux autres chenaux de la plaine d'inondation. Un volume de sédiments estim

  8. Hydrogeology of the Mogollon Highlands, central Arizona

    Science.gov (United States)

    Parker, John T.C.; Steinkampf, William C.; Flynn, Marilyn E.

    2005-01-01

    The Mogollon Highlands, 4,855 square miles of rugged, mountainous terrain at the southern edge of the Colorado Plateau in central Arizona, is characterized by a bedrock-dominated hydrologic system that results in an incompletely integrated regional ground-water system, flashy streamflow, and various local water-bearing zones that are sensitive to drought. Increased demand on the water resources of the area as a result of recreational activities and population growth have made necessary an increased understanding of the hydrogeology of the region. The U.S. Geological Survey conducted a study of the geology and hydrology of the region in cooperation with the Arizona Department of Water Resources under the auspices of the Arizona Rural Watershed Initiative, a program launched in 1998 to assist rural areas in dealing with water-resources issues. The study involved the analysis of geologic maps, surface-water and ground-water flow, and water and rock chemical data and spatial relationships to characterize the hydrogeologic framework. The study area includes the southwestern corner of the Colorado Plateau and the Mogollon Rim, which is the eroded edge of the plateau. A 3,000- to 4,000-foot sequence of early to late Paleozoic sedimentary rocks forms the generally south-facing scarp of the Mogollon Rim. The area adjacent to the edge of the Mogollon Rim is an erosional landscape of rolling, step-like terrain exposing Proterozoic metamorphic and granitic rocks. Farther south, the Sierra Ancha and Mazatzal Mountain ranges, which are composed of various Proterozoic rocks, flank an alluvial basin filled with late Cenozoic sediments and volcanic flows. Eight streams with perennial to intermittent to ephemeral flow drain upland regions of the Mogollon Rim and flow into the Salt River on the southern boundary or the Verde River on the western boundary. Ground-water flow paths generally are controlled by large-scale fracture systems or by karst features in carbonate rocks. Stream

  9. Optimising Regionalisation Techniques: Identifying Centres of Endemism in the Extraordinarily Endemic-Rich Cape Floristic Region

    Science.gov (United States)

    Bradshaw, Peter L.; Colville, Jonathan F.; Linder, H. Peter

    2015-01-01

    We used a very large dataset (>40% of all species) from the endemic-rich Cape Floristic Region (CFR) to explore the impact of different weighting techniques, coefficients to calculate similarity among the cells, and clustering approaches on biogeographical regionalisation. The results were used to revise the biogeographical subdivision of the CFR. We show that weighted data (down-weighting widespread species), similarity calculated using Kulczinsky’s second measure, and clustering using UPGMA resulted in the optimal classification. This maximized the number of endemic species, the number of centres recognized, and operational geographic units assigned to centres of endemism (CoEs). We developed a dendrogram branch order cut-off (BOC) method to locate the optimal cut-off points on the dendrogram to define candidate clusters. Kulczinsky’s second measure dendrograms were combined using consensus, identifying areas of conflict which could be due to biotic element overlap or transitional areas. Post-clustering GIS manipulation substantially enhanced the endemic composition and geographic size of candidate CoEs. Although there was broad spatial congruence with previous phytogeographic studies, our techniques allowed for the recovery of additional phytogeographic detail not previously described for the CFR. PMID:26147438

  10. An Autosomal Factor from Drosophila Arizonae Restores Normal Spermatogenesis in Drosophila Mojavensis Males Carrying the D. Arizonae Y Chromosome

    Science.gov (United States)

    Pantazidis, A. C.; Galanopoulos, V. K.; Zouros, E.

    1993-01-01

    Males of Drosophila mojavensis whose Y chromosome is replaced by the Y chromosome of the sibling species Drosophila arizonae are sterile. It is shown that genetic material from the fourth chromosome of D. arizonae is necessary and sufficient, in single dose, to restore fertility in these males. In introgression and mapping experiments this material segregates as a single Mendelian factor (sperm motility factor, SMF). Light and electron microscopy studies of spermatogenesis in D. mojavensis males whose Y chromosome is replaced by introgression with the Y chromosome of D. arizonae (these males are symbolized as mojY(a)) revealed postmeiotic abnormalities all of which are restored when the SMF of D. arizonae is co-introgressed (these males are symbolized as mojY(a)SMF(a)). The number of mature sperm per bundle in mojY(a)SMF(a) is slightly less than in pure D. mojavensis and is even smaller in males whose fertility is rescued by introgression of the entire fourth chromosome of D. arizonae. These observations establish an interspecific incompatibility between the Y chromosome and an autosomal factor (or more than one tightly linked factors) that can be useful for the study of the evolution of male hybrid sterility in Drosophila and the genetic control of spermatogenesis. PMID:8514139

  11. Effects on Funding Equity of the Arizona Tax Credit Law

    Directory of Open Access Journals (Sweden)

    Glen Y. Wilson

    2000-08-01

    Full Text Available This article examines the results from the first year (1998 of the Arizona Education Tax Credit program. The tax credit law allows individuals a dollar- for-dollar tax credit of $500 for donations to private schools and a dollar-for-dollar tax credit of $200 for donations to public schools. Although one justification for this statute was that it would help lower income students, the primary beneficiaries of this program tend to be the relatively well off. The author concludes that Arizona's tax credit law increases educational funding inequity in Arizona. Data for 1999, only recently made available, show a 159.1 percent increase in total contributions and an exacerbation of the trends noted here.

  12. Taenia solium in Europe: Still endemic?

    Science.gov (United States)

    Devleesschauwer, Brecht; Allepuz, Alberto; Dermauw, Veronique; Johansen, Maria V; Laranjo-González, Minerva; Smit, G Suzanne A; Sotiraki, Smaragda; Trevisan, Chiara; Wardrop, Nicola A; Dorny, Pierre; Gabriël, Sarah

    2017-01-01

    The pork tapeworm, Taenia solium, causes an important economic and health burden, mainly in rural or marginalized communities of sub-Saharan Africa, Asia, and Latin-America. Although improved pig rearing conditions seem to have eliminated the parasite in most Western European countries, little is known about the true endemicity status of T. solium throughout Europe. Three recent reviews indicate that autochthonous human T. solium taeniasis/cysticercosis may be possible in Europe, but that current peer-reviewed literature is biased towards Western Europe. Officially reported data on porcine cysticercosis are highly insufficient. Favourable conditions for local T. solium transmission still exist in eastern parts of Europe, although the ongoing integration of the European Union is speeding up modernisation and intensification of the pig sector. Further evidence is urgently needed to fill the gaps on the European T. solium endemicity map. We urge to make human cysticercosis notifiable and to improve the reporting of porcine cysticercosis. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Diversity and endemism of Peruvian mammals

    Directory of Open Access Journals (Sweden)

    Víctor Pacheco

    2011-07-01

    Full Text Available We present an annotated list for all land, aquatic and marine mammals known to occur in Peru and their distribution by ecoregions. We also present species conservation status according to international organizations and the legal conservation status in Peru. At present, we record 508 species, in 13 orders, 50 families, and 218 genera, making Peru the third most diverse country with regards to mammals in the New World, after Brazil and Mexico, and the fifth most diverse country for mammals in the World. This diversity includes 40 didelphimorphs, 2 paucituberculates, 1 manatee, 6 cingulates, 7 pilosa, 39 primates, 162 rodents, 1 rabbit, 2 soricomorphs, 165 bats, 34 carnivores, 2 perissodactyls, and 47 cetartiodactyls. Bats and rodents (327 species represent almost two thirds of total diversity (64% for Peru. Five genera and 65 species (12.8% are endemics to Peru, with the majority of these being rodents (45 species, 69,2%. Most of the endemic species are restricted to the Yungas of the eastern slope of the Andes (39 species, 60% followed by Selva Baja (14 species, 21.5%. The taxonomic status of some species is commented on, when those depart from accepted taxonomy. The marsupial Marmosa phaea; the rodents Melanomys caliginosus, M. robustulus, and Echinoprocta rufescens; the shrew Cryptotis equatoris; the bats Anoura fistulata, Phyllostomus latifolius, Artibeus ravus, Cynomops greenhalli, Eumops maurus, and Rhogeessa velilla; and the carnivore Nasuella olivacea are first records of species occurrence in Peru. Finally, we also include a list of 15 non-native species.

  14. 75 FR 64681 - Pistachios Grown in California, Arizona, and New Mexico; Continuance Referendum

    Science.gov (United States)

    2010-10-20

    ... Service 7 CFR Part 983 [Doc. No. AMS-FV-10-0077; FV10-983-3 CR] Pistachios Grown in California, Arizona..., Arizona, and New Mexico pistachio producers to determine whether they favor continuance of the marketing order regulating the handling of pistachios grown in California, Arizona, and New Mexico. DATES: The...

  15. Minority Student Progress Report 2009: A Snapshot of Arizona's Educational Achievement

    Science.gov (United States)

    Morel-Seytoux, Sylvie

    2009-01-01

    The Arizona Minority Education Policy Analysis Center (AMEPAC) is a policy center of the Arizona Commission for Postsecondary Education. AMEPAC's mission is to stimulate, through studies, statewide discussion, and debate, constructive improvement of Arizona minority students' early awareness, access, and achievement throughout the educational…

  16. Evaluating the ecological economic success of riparian restoration projects in Arizona (Abstract)

    Science.gov (United States)

    Gary B. Snider

    2000-01-01

    The past 4 years the Arizona Water Protection Fund provided more than $25 million to individuals and organizations for stream and riparian restoration projects in Arizona. Information which increases the awareness of the value of Arizona's riparian systems is crucial to the incorporation of ecosystem services into decision-making frameworks, which are largely...

  17. Arizona Likely Voter Survey on Proposed Legislation to Enhance School Choice

    Science.gov (United States)

    Kenski, Margaret C.

    2005-01-01

    This report contains the results of a telephone survey of 602 likely Arizona voters on various measures to enhance school choice in Arizona. This research was conducted by Arizona Opinion of Tucson for The Milton and Rose D. Friedman Foundation of Indianapolis. All fieldwork was conducted on March 23-26, and 28-29, 2005 by DataCall Inc. of…

  18. Response of the desert shrub Krameria parvifolia after ten years of chronic gamma irradiation

    International Nuclear Information System (INIS)

    Vollmer, A.T.; Bamberg, S.A.

    1975-01-01

    A northern Mojave Desert shrub community was irradiated by a 137 Cs source for a ten-year period. Leaf and fruit production, cover, and percent live stem of Krameria parvifolia shrubs were found to respond significantly to a radiation gradient with exposure rates ranging from 0.1 to 10 R/day. Fruit and leaf production were greatly reduced at exposures over 6 R/day. Above 7 R/day 16% of the shrubs were dead compared to 1.2% in a non-irradiated area. Reduced cover, density and live stem values indicate a trend toward a lower status of Krameria in the community at cumulative exposures above 25 kR. Observations indicate that an equilibrium in response to irradiation has not yet occurred. Radiosensitivity of K. parvifolia is attributed in part to its phenology. (author)

  19. Response of the desert shrub Krameria parvifolia after ten years of chronic gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Vollmer, A T; Bamberg, S A [California Univ., Los Angeles (USA). Lab. of Nuclear Medicine and Radiation Biology

    1975-12-01

    A northern Mojave Desert shrub community was irradiated by a /sup 137/Cs source for a ten-year period. Leaf and fruit production, cover, and percent live stem of Krameria parvifolia shrubs were found to respond significantly to a radiation gradient with exposure rates ranging from 0.1 to 10 R/day. Fruit and leaf production were greatly reduced at exposures over 6 R/day. Above 7 R/day 16% of the shrubs were dead compared to 1.2% in a non-irradiated area. Reduced cover, density and live stem values indicate a trend toward a lower status of Krameria in the community at cumulative exposures above 25 kR. Observations indicate that an equilibrium in response to irradiation has not yet occurred. Radiosensitivity of K. parvifolia is attributed in part to its phenology.

  20. Hydroclimatological Controls of Endemic and Non-endemic Cholera of the 20th Century

    Science.gov (United States)

    Jutla, A. S.; Whitcombe, E.; Colwell, R.

    2012-12-01

    Cholera remains a major public health threat for the developing countries. Since the causative agent, Vibrio cholerae, is autochthonous to aquatic environment, it is not possible to eradicate the agent of the disease. Hydroclimatology based prediction and prevention strategies can be implemented in disease susceptible regions for reducing incidence rates. However, the precise role of hydrological and climatological processes, which will further aid in development of suitable prediction models, in creating spatial and temporal environmental conditions favorable for disease outbreak has not been adequately quantified. Here, we show distinction between seasonality and occurrence of cholera in epidemic and non-endemic regions. Using historical cholera mortality data, from the late 1800s for 27 locations in the Indian subcontinent, we show that non-endemic regions are generally located close to regional river systems but away from the coasts and are characterized by single sporadic outbreak in a given year. Increase in air temperature during the low river flow season increases evaporation, leading to an optimal salinity and pH required for bacterial growth. Thereafter, monsoonal rainfall, leads to interactions of contaminated river waters via human activity resulting in cholera epidemics. Endemic regions are located close to coasts where cholera outbreak occurs twice (spring and fall) in a year. Spring outbreak is generally associated with intrusion of bacterial seawater to inland whereas the fall peak is correlated with widespread flooding and cross-contamination of water resources via increased precipitation. This may be one of the first studies to hydroclimatologically quantitatively the seasonality of cholera in both endemic and non-endemic regions. Our results prompt the need of region and cause-specific prediction models for cholera, employing appropriate environmental determinants.

  1. Role of nurse shrubs for restoration planting of two conifers in southeast of Mu Us Sandland, China.

    Science.gov (United States)

    Tian, Li; Wang, Xiaoan

    2015-01-01

    Two-year-old pine seedlings, Pinus tabulaeformis and Pinus sylvestris were planted under the canopies of three shrub species and in open areas to test for facilitation during seedling establishment in southeast of Mu Us Sandland in northern part of Shaanxi, China. Pine seedlings establishment were assessed three times within three consecutive growing seasons. Height, area and volume of shrubs were measured. Microclimate conditions (light intensity, air temperature and soil temperature and moisture) were recorded in four microhabitats. Near surface light intensity, air temperature and soil temperature were lower under shrubs, which led to higher soil moisture and pine seedlings under the canopy of shrub species. Pine seedlings survival was remarkably higher when planted under the canopy of shrub species (65.7% for P. tabulaeformis and 60.6% for P. sylvestris) as compared with open areas (22.4% for P. tabulaeformis and 38% for P. sylvestris). P. tabulaeformis with shade-tolerance trait expressed high survival of seedlings as compared to that of P. sylvestris seedlings under the canopy of shrub species (Tukey test, P shrub (Caragana korshinskii and Amorpha fruticosa) showed continuously facilitation during moderate drought stress (summer 2012, 2013 and 2014), but dense and small shrub (Caragana korshinskii) reduced the establishment of seedlings possibly for light competition. Salix cheilophila showed a facilitation effect in growing seasons, but the effect of allelopathy led to high mortality of seedlings under their canopy. in addition, two pine growths were not inhibited when planted under three shrubs. In conclusions, nurse-shrub facilitation can be used as an effective restoration strategy in this sandland. However, use of shrubs as nurse plants depends on their canopy structure and ecological impacts; the selection of target species depends on their shade tolerance traits.

  2. Shrub type dominates the vertical distribution of leaf C : N : P stoichiometry across an extensive altitudinal gradient

    Science.gov (United States)

    Zhao, Wenqiang; Reich, Peter B.; Yu, Qiannan; Zhao, Ning; Yin, Chunying; Zhao, Chunzhang; Li, Dandan; Hu, Jun; Li, Ting; Yin, Huajun; Liu, Qing

    2018-04-01

    Understanding leaf stoichiometric patterns is crucial for improving predictions of plant responses to environmental changes. Leaf stoichiometry of terrestrial ecosystems has been widely investigated along latitudinal and longitudinal gradients. However, very little is known about the vertical distribution of leaf C : N : P and the relative effects of environmental parameters, especially for shrubs. Here, we analyzed the shrub leaf C, N and P patterns in 125 mountainous sites over an extensive altitudinal gradient (523-4685 m) on the Tibetan Plateau. Results showed that the shrub leaf C and C : N were 7.3-47.5 % higher than those of other regional and global flora, whereas the leaf N and N : P were 10.2-75.8 % lower. Leaf C increased with rising altitude and decreasing temperature, supporting the physiological acclimation mechanism that high leaf C (e.g., alpine or evergreen shrub) could balance the cell osmotic pressure and resist freezing. The largest leaf N and high leaf P occurred in valley region (altitude 1500 m), likely due to the large nutrient leaching from higher elevations, faster litter decomposition and nutrient resorption ability of deciduous broadleaf shrub. Leaf N : P ratio further indicated increasing N limitation at higher altitudes. Interestingly, drought severity was the only climatic factor positively correlated with leaf N and P, which was more appropriate for evaluating the impact of water status than precipitation. Among the shrub ecosystem and functional types (alpine, subalpine, montane, valley, evergreen, deciduous, broadleaf, and conifer), their leaf element contents and responses to environments were remarkably different. Shrub type was the largest contributor to the total variations in leaf stoichiometry, while climate indirectly affected the leaf C : N : P via its interactive effects on shrub type or soil. Collectively, the large heterogeneity in shrub type was the most important factor explaining the overall leaf C : N : P variations

  3. Cellular-automata model of the dwarf shrubs populations and communities dynamics

    Directory of Open Access Journals (Sweden)

    A. S. Komarov

    2015-06-01

    Full Text Available The probabilistic cellular-automata model of development and long-time dynamics of dwarf shrub populations and communities is developed. It is based on the concept of discrete description of the plant ontogenesis and joint model approaches in terms of probabilistic cellular automata and L-systems by Lindenmayer. Short representation of the basic model allows evaluation of the approach and software implementation. The main variables of the model are a number of partial bushes in clones or area projective cover. The model allows us to investigate the conditions of self-maintenance and sustainability population under different environmental conditions (inaccessibility of the territory for settlement, mosaic moisture conditions of soil and wealth. The model provides a forecast of the total biomass dynamics shrubs and their fractions (stems, leaves, roots, fine roots, fruits on the basis of the data obtained in the discrete description of ontogenesis and further information on the productivity of the plant fractions. The inclusion of the joint dynamics of biomass of shrubs and soil in EFIMOD models cycle of carbon and nitrogen to evaluate the role of shrubs in these circulations, especially at high impact, such as forest fires and clear cutting, allow forecasting of the dynamics of populations and ecosystem functions of shrubs (regulation of biogeochemical cycles maintaining biodiversity, participation in the creation of non-wood products with changing climatic conditions and strong damaging effects (logging, fires; and application of the models developed to investigate the stability and productivity of shrubs and their participation in the cycle of carbon and nitrogen in different climatic and edaphic conditions.

  4. Effects of shrub and tree cover increase on the near-surface atmosphere in northern Fennoscandia

    Directory of Open Access Journals (Sweden)

    J. H. Rydsaa

    2017-09-01

    Full Text Available Increased shrub and tree cover in high latitudes is a widely observed response to climate change that can lead to positive feedbacks to the regional climate. In this study we evaluate the sensitivity of the near-surface atmosphere to a potential increase in shrub and tree cover in the northern Fennoscandia region. We have applied the Weather Research and Forecasting (WRF model with the Noah-UA land surface module in evaluating biophysical effects of increased shrub cover on the near-surface atmosphere at a fine resolution (5.4 km  ×  5.4 km. Perturbation experiments are performed in which we prescribe a gradual increase in taller vegetation in the alpine shrub and tree cover according to empirically established bioclimatic zones within the study region. We focus on the spring and summer atmospheric response. To evaluate the sensitivity of the atmospheric response to inter-annual variability in climate, simulations were conducted for two contrasting years, one warm and one cold. We find that shrub and tree cover increase leads to a general increase in near-surface temperatures, with the highest influence seen during the snowmelt season and a more moderate effect during summer. We find that the warming effect is stronger in taller vegetation types, with more complex canopies leading to decreases in the surface albedo. Counteracting effects include increased evapotranspiration, which can lead to increased cloud cover, precipitation, and snow cover. We find that the strength of the atmospheric feedback is sensitive to snow cover variations and to a lesser extent to summer temperatures. Our results show that the positive feedback to high-latitude warming induced by increased shrub and tree cover is a robust feature across inter-annual differences in meteorological conditions and will likely play an important role in land–atmosphere feedback processes in the future.

  5. Sparse trees and shrubs confers a high biodiversity to pastures: Case study on spiders from Transylvania.

    Science.gov (United States)

    Gallé, Róbert; Urák, István; Nikolett, Gallé-Szpisjak; Hartel, Tibor

    2017-01-01

    The integration of food production and biodiversity conservation represents a key challenge for sustainability. Several studies suggest that even small structural elements in the landscape can make a substantial contribution to the overall biodiversity value of the agricultural landscapes. Pastures can have high biodiversity potential. However, their intensive and monofunctional use typically erodes its natural capital, including biodiversity. Here we address the ecological value of fine scale structural elements represented by sparsely scattered trees and shrubs for the spider communities in a moderately intensively grazed pasture in Transylvania, Eastern Europe. The pasture was grazed with sheep, cattle and buffalo (ca 1 Livestock Unit ha-1) and no chemical fertilizers were applied. Sampling sites covered the open pasture as well as the existing fine-scale heterogeneity created by scattered trees and shrub. 40 sampling locations each being represented by three 1 m2 quadrats were situated in a stratified design while assuring spatial independency of sampling locations. We identified 140 species of spiders, out of which 18 were red listed and four were new for the Romanian fauna. Spider species assemblages of open pasture, scattered trees, trees and shrubs and the forest edge were statistically distinct. Our study shows that sparsely scattered mature woody vegetation and shrubs substantially increases the ecological value of managed pastures. The structural complexity provided by scattered trees and shrubs makes possible the co-occurrence of high spider diversity with a moderately high intensity grazing possible in this wood-pasture. Our results are in line with recent empirical research showing that sparse trees and shrubs increases the biodiversity potential of pastures managed for commodity production.

  6. Recent expansion of erect shrubs in the Low Arctic: evidence from Eastern Nunavik

    International Nuclear Information System (INIS)

    Tremblay, Benoît; Lévesque, Esther; Boudreau, Stéphane

    2012-01-01

    In order to characterize shrub response near the treeline in Eastern Nunavik (Québec), a region under extensive warming since the 1990s, we compared two series (1964 and 2003) of vertical aerial photos from the vicinity of Kangiqsualujjuaq. Our study revealed a widespread increase in erect woody vegetation cover. During the 40 years spanning the two photo series, erect shrub and tree cover increased markedly on more than half of the land surface available for new colonization or infilling. Within the 7.2 km 2 analysed, areas with dense shrub and tree cover (>90%) increased from 34% to 44% whereas areas with low cover (<10%) shrank from 45% to 29%. This increase in cover of trees and shrubs occurred throughout the landscape regardless of altitude, slope angle and exposure, although to varying extents. The main shrub species involved in this increase was Betula glandulosa Michx. (dwarf birch), which was present in 98% and dominant in 85% of the 345 plots. In addition, numerous seedlings and saplings of Larix laricina (Du Roi) K Koch (eastern larch) were found above the treeline (25% of the plots), suggesting that the altitudinal treeline might shift upslope in the near future. Sites that remained devoid of erect woody vegetation in 2003 were either characterized by the absence of a suitable seedbed or by harsh local microclimatic conditions (wind exposure or excessive drainage). Our results indicate dramatic increases in shrub and tree cover at a Low Arctic site in Eastern Nunavik, contributing to a growing number of observations of woody vegetation change from various areas around the North. (letter)

  7. Comparison of immune responses to a killed bivalent whole cell oral cholera vaccine between endemic and less endemic settings.

    Science.gov (United States)

    Desai, Sachin N; Akalu, Zenebe; Teferi, Mekonnen; Manna, Byomkesh; Teshome, Samuel; Park, Ju Yeon; Yang, Jae Seung; Kim, Deok Ryun; Kanungo, Suman; Digilio, Laura

    2016-02-01

    Studies on safety, immunogenicity and efficacy of the killed, bivalent whole cell oral cholera vaccine (Shanchol) have been conducted in historically endemic settings of Asia. Recent cholera vaccination campaigns in Haiti and Guinea have also demonstrated favourable immunogenicity and effectiveness in nonendemic outbreak settings. We performed a secondary analysis, comparing immune responses of Shanchol from two randomised controlled trials performed in an endemic and a less endemic area (Addis Ababa) during a nonoutbreak setting. While Shanchol may offer some degree of immediate protection in primed populations living in cholera endemic areas, as well as being highly immunogenic in less endemic settings, understanding the characteristics of immune responses in each of these areas is vital in determining ideal dosing strategies that offer the greatest public health impact to populations from areas with varying degrees of cholera endemicity. © 2015 John Wiley & Sons Ltd.

  8. Age distributions of Greenlandic dwarf shrubs support concept of negligible actuarial senescence

    DEFF Research Database (Denmark)

    Dahlgren, Johan; Rizzi, Silvia; Schweingruber, Fritz

    2016-01-01

    shrub species from 863 taproot samples collected in coastal east Greenland. Penalized composite link models (pclm) were used to fill gaps in the observed age ranges, caused by low species-specific sample sizes in relation to life span. Resulting distributions indicate that mortality patterns...... are independent of age. Actuarial senescence is thus negligible in these dwarf shrub populations. We suggest that smoothing techniques such as pclm enable consideration of noisy age data for determining age distributions. These distributions may, in turn, reveal age effects on demographic rates. Moreover, age...

  9. Environmental Limits of Tall Shrubs in Alaska’s Arctic National Parks

    Science.gov (United States)

    Swanson, David K.

    2015-01-01

    We sampled shrub canopy volume (height times area) and environmental factors (soil wetness, soil depth of thaw, soil pH, mean July air temperature, and typical date of spring snow loss) on 471 plots across five National Park Service units in northern Alaska. Our goal was to determine the environments where tall shrubs thrive and use this information to predict the location of future shrub expansion. The study area covers over 80,000 km2 and has mostly tundra vegetation. Large canopy volumes were uncommon, with volumes over 0.5 m3/m2 present on just 8% of plots. Shrub canopy volumes were highest where mean July temperatures were above 10.5°C and on weakly acid to neutral soils (pH of 6 to 7) with deep summer thaw (>80 cm) and good drainage. On many sites, flooding helped maintain favorable soil conditions for shrub growth. Canopy volumes were highest where the typical snow loss date was near 20 May; these represent sites that are neither strongly wind-scoured in the winter nor late to melt from deep snowdrifts. Individual species varied widely in the canopy volumes they attained and their response to the environmental factors. Betula sp. shrubs were the most common and quite tolerant of soil acidity, cold July temperatures, and shallow thaw depths, but they did not form high-volume canopies under these conditions. Alnus viridis formed the largest canopies and was tolerant of soil acidity down to about pH 5, but required more summer warmth (over 12°C) than the other species. The Salix species varied widely from S. pulchra, tolerant of wet and moderately acid soils, to S. alaxensis, requiring well-drained soils with near neutral pH. Nearly half of the land area in ARCN has mean July temperatures of 10.5 to 12.5°C, where 2°C of warming would bring temperatures into the range needed for all of the potential tall shrub species to form large canopies. However, limitations in the other environmental factors would probably prevent the formation of large shrub canopies

  10. Soil surface temperatures reveal moderation of the urban heat island effect by trees and shrubs

    DEFF Research Database (Denmark)

    Edmondson, Jill L; Stott, Iain; Davies, Zoe G

    2016-01-01

    months increased by 0.6 °C over the 5 km from the city outskirts to the centre. Trees and shrubs in non-domestic greenspace reduced mean maximum daily soil surface temperatures in the summer by 5.7 °C compared to herbaceous vegetation, but tended to maintain slightly higher temperatures in winter. Trees...... in domestic gardens, which tend to be smaller, were less effective at reducing summer soil surface temperatures. Our findings reveal that the UHI effects soil temperatures at a city-wide scale, and that in their moderating urban soil surface temperature extremes, trees and shrubs may help to reduce...

  11. Behavior of pyrophite shrubs in mediterranean terrestrial ecosystems (i): Population and reproductive model.

    Science.gov (United States)

    Usó-Doménech, Josep-Lluis; Nescolarde-Selva, Josué-Antonio; Lloret-Climent, Miguel; González-Franco, Lucía

    2018-03-01

    The mathematical submodel ULEX is used to study the dynamic behavior of the green, floral and woody biomass of the main pyrophite shrub species, the gorse (Ulex parviflorus Pourret), and its relationship with other shrub species, typical of a Mediterranean ecosystem. The focus are the ecological conditions of post-fire stage growth, and its efficacy as a protective cover against erosion processes in the short, medium and long term, both in normal conditions and at the limits of desertification conditions. The model sets a target to observe the behavior and to anticipate and consequently intervene with adequate protection, restoration and management measures. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. 3D View of Grand Canyon, Arizona

    Science.gov (United States)

    2000-01-01

    The Grand Canyon is one of North America's most spectacular geologic features. Carved primarily by the Colorado River over the past six million years, the canyon sports vertical drops of 5,000 feet and spans a 445-kilometer-long stretch of Arizona desert. The strata along the steep walls of the canyon form a record of geologic time from the Paleozoic Era (250 million years ago) to the Precambrian (1.7 billion years ago).The above view was acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument aboard the Terra spacecraft. Visible and near infrared data were combined to form an image that simulates the natural colors of water and vegetation. Rock colors, however, are not accurate. The image data were combined with elevation data to produce this perspective view, with no vertical exaggeration, looking from above the South Rim up Bright Angel Canyon towards the North Rim. The light lines on the plateau at lower right are the roads around the Canyon View Information Plaza. The Bright Angel Trail, which reaches the Colorado in 11.3 kilometers, can be seen dropping into the canyon over Plateau Point at bottom center. The blue and black areas on the North Rim indicate a forest fire that was smoldering as the data were acquired on May 12, 2000.Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as

  13. Does sex matter? Gender-specificity and its influence on site-chronologies in the common dioecious shrub Juniperus communis

    NARCIS (Netherlands)

    Shetti, Rohan; Buras, Allan; Smiljanic, Marko; Hallinger, Martin; Grigoriev, Andrey A.; Wilmking, Martin

    2018-01-01

    In recent years an increasing number of studies have shown shrubs to be reliable proxies of environmental conditions in regions where Trees − due to harsh climate conditions − are absent. Although many shrubs are monoecious, some are dioecious, which poses certain questions related to

  14. Effects of Width, Edge and Habitat on the Abundance and Nesting Success of Scrub-shrub Birds in Powerline Corridors

    Science.gov (United States)

    David I. King; Richard B. Chandler; Jeffrey M. Collins; Wayne R. Petersen; Thomas E. Lautzenheiser

    2009-01-01

    Concern about declines in scrub–shrub bird populations has resulted in efforts to create and maintain habitat for these species. Vegetation within powerline corridors is managed to prevent contact of vegetation with transmission lines, and comprises approximately 2% of all of habitat for scrub–shrub birds in southern New England. Although previous studies have...

  15. Dwarf shrub and grass vegetation resistant to long-term experimental warming while microarthropod abundance declines on the Falkland Islands

    NARCIS (Netherlands)

    Bokhorst, S.; Convey, P.; Huiskes, A.; Aerts, R.; Huiskes, A.

    2017-01-01

    Dwarf shrubs are a dominant plant type across many regions of the Earth and have hence a large impact on carbon and nutrient cycling rates. Climate change impacts on dwarf shrubs have been extensively studied in the Northern Hemisphere, and there appears to be large variability in response between

  16. Force of habit: shrubs, trees and contingent evolution of wood anatomical diversity using Croton (Euphorbiaceae) as a model system

    Science.gov (United States)

    Rafael Arévalo; Benjamin W. van Ee; Ricarda Riina; Paul E. Berry; Alex C. Wiedenhoeft

    2017-01-01

    Background and Aims Wood is a major innovation of land plants, and is usually a central component of the body plan for two major plant habits: shrubs and trees. Wood anatomical syndromes vary between shrubs and trees, but no prior work has explicitly evaluated the contingent evolution of wood anatomical diversity in the context...

  17. The role of rodents in the seed fate of a thorny shrub in an ancient wood pasture

    NARCIS (Netherlands)

    Scheper, Jeroen; Smit, Christian

    2011-01-01

    Thorny shrubs play a crucial role for the diversity and dynamics in wood pastures: they protect non-defended plants from large herbivores and thus facilitate tree establishment in the landscape through associational resistance. How thorny shrubs themselves establish in wood pastures - the main

  18. The effect of the halophytic shrub Lycium ruthenium (Mutt) on selected soil properties of a desert ecosystem in central Iran

    Science.gov (United States)

    Gholam Ali Jalali; Hossein Akbarian; Charles Rhoades; Hamed Yousefzadeh

    2012-01-01

    We compared soil properties beneath naturally-occurring patches of Lycium ruthenicum Murray (fam. Solanaceae) to evaluate the shrub’s potential to improve the fertility of saline soils. Soil pH, total nitrogen and carbon and extractable potassium, magnesium and phosphorus were respectively significantly higher in the A and B horizons of Lycium shrub patches...

  19. Effect of industrial air pollution on decorative trees and shrubs in the area of the Nitrogen Fertilizer Factory at Pulawy

    Energy Technology Data Exchange (ETDEWEB)

    Kawecka, A

    1973-01-01

    This paper discusses the effects that the gaseous wastes from a nitrogen fertilizer plant have on decorative trees and shrubs. It lists 28 species of broadleaved trees and shrubs, and assigns them to four groups according to their resistance or susceptibility to the pollution. 6 references.

  20. Growing Shrubs at the George O. White State Forest Nursery: What Has Worked and What Has Not

    Science.gov (United States)

    Gregory Hoss

    2006-01-01

    At the George O. White State Forest Nursery in Licking, MO, we annually grow about 20 species of shrubs. That number has been larger in some years. For most species, we purchase seeds locally and process them at our nursery. Our shrubs are used for wetland restoration, windbreaks, visual screens, riparian buffers, and wildlife plantings.

  1. 33 CFR 100.1102 - Marine Events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and Headgate Dam...

    Science.gov (United States)

    2010-07-01

    ... River, between Davis Dam (Bullhead City, Arizona) and Headgate Dam (Parker, Arizona). 100.1102 Section... MARINE PARADES SAFETY OF LIFE ON NAVIGABLE WATERS § 100.1102 Marine Events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and Headgate Dam (Parker, Arizona). (a) General. Sponsors are...

  2. Endemic human fasciolosis in the Bolivian Altiplano.

    Science.gov (United States)

    Parkinson, M; O'Neill, S M; Dalton, J P

    2007-05-01

    Fasciolosis, caused by trematodes of the genus Fasciola, is an emerging disease of humans. One of the highest levels of human fasciolosis hepatica is found amongst the indigenous Aymaran people of the Northern Bolivian Altiplano. A meta-analysis of epidemiological surveys from 38 communities in the region demonstrates that fasciolosis has been endemic in the region since at least 1984 and is a zoonosis of rural communities. Human and bovine fasciolosis is associated with the communities lying in the plain from Lake Titicaca to La Paz, predominantly in the Los Andes province. In Los Andes incidences of up to 67% of population cohorts were found, and prevalence is age-related with the highest infection rate in children aged 8-11 years.

  3. Bursting endemic bubbles in an adaptive network

    Science.gov (United States)

    Sherborne, N.; Blyuss, K. B.; Kiss, I. Z.

    2018-04-01

    The spread of an infectious disease is known to change people's behavior, which in turn affects the spread of disease. Adaptive network models that account for both epidemic and behavioral change have found oscillations, but in an extremely narrow region of the parameter space, which contrasts with intuition and available data. In this paper we propose a simple susceptible-infected-susceptible epidemic model on an adaptive network with time-delayed rewiring, and show that oscillatory solutions are now present in a wide region of the parameter space. Altering the transmission or rewiring rates reveals the presence of an endemic bubble—an enclosed region of the parameter space where oscillations are observed.

  4. ANTIGENAEMIA AS AN INDICATOR OF FILARIAL ENDEMICITY

    Directory of Open Access Journals (Sweden)

    F. Partono

    2012-09-01

    Full Text Available This is a report of 1 -year evaluation of chemotherapeutic intervention in an area of Indonesia endemic for lymphatic filariasis. Control measures were initiated in 1977 by parasite control, informal health educa­tion, and community participation at the village level, well in accord with the WHO-concept of health for all. Diethylcarbamazine (DEC was mass distributed in 1977 and 1988, and selectively distributed in 1978, 1979, 1981, and 1982 to those who were micro-filaraemic prior to DEC treatments, those with a history of adenoly mphangitis over the previous one year period, and to all new comers. In addition, each villager with acute symptoms of adenolymphangitis was immediately treated with a single course of 300 mg DEC for 10 days. No intervention measures were taken between 1982 to 1988, and no attempt was taken to control the vector or to restrict movement between controlled and uncontrolled areas during the whole studies. With these measures, the microfilaria (mf rate decreased from 30% to 0%, the adenolymphangitis rate from 46% to 11%, and the elephantiasis rate from 35% to 3%. The abatement of acute and chronic filarial symptoms over the study period and the disappearance of microfilaremia in the community are pointing towards the possibility of eradicating the partasite from the community. To test this hypothesis, serum samples were tested for circulating filarial antigen by a two-site antigen capture assay employing anti-phosphorylcholine monoclonal antibodies. There was a sharp fall in circulating antigenaemia, demonstrating that infection has either been eliminated from nearly all villagers, or that intensity of infection is now undetectably low. We feel that antigenaemia can be used as an indicator of filarial endemicity.

  5. Comparative phylogeography of endemic Azorean arthropods.

    Science.gov (United States)

    Parmakelis, Aristeidis; Rigal, François; Mourikis, Thanos; Balanika, Katerina; Terzopoulou, Sofia; Rego, Carla; Amorim, Isabel R; Crespo, Luís; Pereira, Fernando; Triantis, Kostas A; Whittaker, Robert J; Borges, Paulo A V

    2015-11-11

    For a remote oceanic archipelago of up to 8 Myr age, the Azores have a comparatively low level of endemism. We present an analysis of phylogeographic patterns of endemic Azorean island arthropods aimed at testing patterns of diversification in relation to the ontogeny of the archipelago, in order to distinguish between alternative models of evolutionary dynamics on islands. We collected individuals of six species (representing Araneae, Hemiptera and Coleoptera) from 16 forest fragments from 7 islands. Using three mtDNA markers, we analysed the distribution of genetic diversity within and between islands, inferred the differentiation time-frames and investigated the inter-island migration routes and colonization patterns. Each species exhibited very low levels of mtDNA divergence, both within and between islands. The two oldest islands were not strongly involved in the diffusion of genetic diversity within the archipelago. The most haplotype-rich islands varied according to species but the younger, central islands contributed the most to haplotype diversity. Colonization events both in concordance with and in contradiction to an inter-island progression rule were inferred, while a non-intuitive pattern of colonization from western to eastern islands was also inferred. The geological development of the Azores has followed a less tidy progression compared to classic hotspot archipelagos, and this is reflected in our findings. The study species appear to have been differentiating within the Azores for <2 Myr, a fraction of the apparent life span of the archipelago, which may indicate that extinction events linked to active volcanism have played an important role. Assuming that after each extinction event, colonization was initiated from a nearby island hosting derived haplotypes, the apparent age of species diversification in the archipelago would be moved closer to the present after each extinction-recolonization cycle. Exploiting these ideas, we propose a general

  6. Tree and shrub expansion over the past 34 years at the tree-line near Abisko, Sweden.

    Science.gov (United States)

    Rundqvist, Sara; Hedenås, Henrik; Sandström, Anneli; Emanuelsson, Urban; Eriksson, Håkan; Jonasson, Christer; Callaghan, Terry V

    2011-09-01

    Shrubs and trees are expected to expand in the sub-Arctic due to global warming. Our study was conducted in Abisko, sub-arctic Sweden. We recorded the change in coverage of shrub and tree species over a 32- to 34-year period, in three 50 x 50 m plots; in the alpine-tree-line ecotone. The cover of shrubs and trees (tree stems (> or =3.5 cm) were noted and positions determined. There has been a substantial increase of cover of shrubs and trees, particularly dwarf birch (Betula nana), and mountain birch (Betula pubescens ssp. czerepanovii), and an establishment of aspen (Populus tremula). The other species willows (Salix spp.), juniper (Juniperus communis), and rowan (Sorbus aucuparia) revealed inconsistent changes among the plots. Although this study was unable to identify the causes for the change in shrubs and small trees, they are consistent with anticipated changes due to climate change and reduced herbivory.

  7. Costs, emissions reductions, and vehicle repair: evidence from Arizona.

    Science.gov (United States)

    Ando, A; McConnell, V; Harrington, W

    2000-04-01

    The Arizona inspection and maintenance (I/M) program provides one of the first opportunities to examine the costs and effectiveness of vehicle emission repair. This paper examines various aspects of emission reductions, fuel economy improvements, and repair costs, drawing data from over 80,000 vehicles that failed the I/M test in Arizona between 1995 and the first half of 1996. We summarize the wealth of data on repair from the Arizona program and highlight its limitations. Because missing or incomplete cost information has been a serious shortcoming for the evaluation of I/M programs, we develop a method for estimating repair costs when they are not reported. We find surprising evidence that almost one quarter of all vehicles that take the I/M test are never observed to pass the test. Using a statistical analysis, we provide some information about the differences between the vehicles that pass and those that do not. Older, more polluting vehicles are much more likely never to pass the I/M test, and their expected repair costs are much higher than those for newer cars. This paper summarizes the evidence on costs and emission reductions in the Arizona program, comparing costs and emissions reductions between cars and trucks. Finally, we examine the potential for more cost-effective repair, first through an analysis of tightening I/M cut points and then by calculating the cost savings of achieving different emission reduction goals when the most cost-effective repairs are made first.

  8. Arizona Traffic Safety Education, K-8. Passenger Safety, Grade 3.

    Science.gov (United States)

    Mesa Public Schools, AZ.

    One in a series designed to assist Arizona elementary and junior high school teachers in developing children's traffic safety skills, this curriculum guide contains four lessons and an appendix of school bus safety tips for use in grade 3. Introductory information provided for the teacher includes basic highway safety concepts, stressing…

  9. 75 FR 51840 - State of Arizona Resource Advisory Council Meeting

    Science.gov (United States)

    2010-08-23

    ... Policy and Management Act of 1976 and the Federal Advisory Committee Act of 1972, the U.S. Department of... on the BLM Arizona National Landscape Conservation System (NLCS), Update on the Renewable Energy... DEPARTMENT OF THE INTERIOR Bureau of Land Management [LLAZ910000.L12100000.XP0000LXSS150A00006100...

  10. 78 FR 44964 - State of Arizona Resource Advisory Council Meetings

    Science.gov (United States)

    2013-07-25

    ... Assessment/Landscape Approach; and Arizona Renewable Energy programs; Use and Formation of Subcommittees on... of 1976 and the Federal Advisory Committee Act of 1972, the U.S. Department of the Interior, Bureau... DEPARTMENT OF THE INTERIOR Bureau of Land Management [LLAZ910000.L12100000.XP0000LXSS150A00006100...

  11. Prevalence of Mycoplasma ovipneumoniae in desert bighorn sheep in Arizona

    Science.gov (United States)

    Justice-Allen, Anne E.; Luedtke, Clint J.; Overstreet, Matthew; Cain, James W.; Stephenson, Thomas R.

    2011-01-01

    To assess the potential for an epizootic of pneumonia to result from either natural immigration or translocation, we compared the seroprevalence to Mycoplasma ovipneumoniae in several populations of desert bighorn sheep in Arizona. We collected blood samples and nasal or oropharyngeal swabs from 124 desert bighorn sheep (Ovis canadensis nelsoni) from 6 populations in Arizona in 2009 and 2010. M. ovipneumoniae organisms were detected by PCR in 22%, whereas antibodies to M. ovipneumoniae were detected in 47% of tested bighorn sheep. Mycoplasma antibodies were not found in 2 of 6 populations, indicating some bighorn sheep populations in Arizona are naïve to this bacterium. In contrast, others had seroprevalence rates up to 80%. We were able to compare seroprevalence rates and titers over time in 9 individuals (7 individuals included in the 124 bighorn sheep sampled in 2009 and 2010, and 2 individuals originally captured in 2006). Antibody titers persisted for 12 months in individuals from the Kofa National Wildlife Refuge (n = 7) while antibody titers appeared to decline in the Kanab Creek population (n = 2). M. ovipneumoniae is present or has been present in several, but not all, populations of bighorn sheep in Arizona. The results demonstrate the importance of routine health testing for future translocation efforts to reduce disease risk for naive populations.

  12. Developing a Distributed Computing Architecture at Arizona State University.

    Science.gov (United States)

    Armann, Neil; And Others

    1994-01-01

    Development of Arizona State University's computing architecture, designed to ensure that all new distributed computing pieces will work together, is described. Aspects discussed include the business rationale, the general architectural approach, characteristics and objectives of the architecture, specific services, and impact on the university…

  13. Monitoring update on four listed plants on the Arizona Strip

    Science.gov (United States)

    Lee E. Hughes

    2001-01-01

    Four listed plants on the Arizona Strip are being monitored for various population characteristics. Pediocactus sileri Engelm. L. Benson and P. bradyi L. Benson have been monitored since 1985-86, Asclepias welshii N & P Holmgren since 1989, and Cycladenia humilis Benth. var. jonesii Welsh & Atwood since 1993. The two pediocactus species were monitored in plots...

  14. Digital Learning Compass: Distance Education State Almanac 2017. Arizona

    Science.gov (United States)

    Seaman, Julia E.; Seaman, Jeff

    2017-01-01

    This brief report uses data collected under the U.S. Department of Education's National Center for Educational Statistics (NCES) Integrated Postsecondary Education Data System (IPEDS) Fall Enrollment survey to highlight distance education data in the state of Arizona . The sample for this analysis is comprised of all active, degree-granting…

  15. Lowland riparian herpetofaunas: the San Pedro River in southeastern Arizona

    Science.gov (United States)

    Philip C. Rosen

    2005-01-01

    Previous work has shown that southeastern Arizona has a characteristic, high diversity lowland riparian herpetofauna with 62-68 or more species along major stream corridors, and 46-54 species in shorter reaches within single biomes, based on intensive fieldwork and museum record surveys. The San Pedro River supports this characteristic herpetofauna, at least some of...

  16. Food habits of Bald Eagles breeding in the Arizona desert

    Science.gov (United States)

    Teryl G. Grubb

    1995-01-01

    Of 1814 foraging attempts, prey captures, or nest deliveries by Bald Eagles (Haliaeetus leucocephalus) in 14 Arizona breeding areas during 1983-1985, 1471 observations were identifiable to at least class: fish (76%), mammal (18%), bird (4%), and reptile/amphibian (2%). Forty-five species were recorded: catfish (Ictalurus punctatus, Pylodictis olivaris), suckers (...

  17. UMTRA water sampling and analysis plan, Tuba City, Arizona

    International Nuclear Information System (INIS)

    1993-09-01

    The purpose of this document is to provide background, guidance, and justification for fiscal year (FY) 1994 water sampling activities for the uranium mil tailings site at Tuba City, Arizona. This sampling and analysis plan will form the basis for groundwater sampling and analysis work orders to be implemented in FY94

  18. Restrictive Language Policy in Practice: English Learners in Arizona

    Science.gov (United States)

    Heineke, Amy J.

    2016-01-01

    As the most restrictive language policy context in the United States, Arizona's monolingual and prescriptive approach to teaching English learners continues to capture international attention. More than five school years after initial implementation, this study uses qualitative data from the individuals doing the policy work to provide a holistic…

  19. Food habits of bald eagles wintering in northern Arizona

    Science.gov (United States)

    Teryl G. Grubb; Roy G. Lopez

    2000-01-01

    We used pellets collected from roosts to supplement incidental foraging observations to identify prey species of Bald Eagles (Haliaeetus leucoughalus) and to evaluate spatial and temporal trends in their food habits while wintering in northern Arizona between 1994-96. We analyzed 1057 pellets collected from 14 roosts, and identified five mammal and...

  20. Arizona State's Origins Project Starts with a Big Bang

    Science.gov (United States)

    Mangan, Katherine

    2009-01-01

    For 12 hours at Arizona State University, a sold-out crowd of 3,000 people gave a group of famous scientists a pop-star welcome, cheering their remarks and lining up for autographs after a day full of discussion about black holes, string theory, and evolutionary biology. At a time when program cuts and faculty layoffs dominate the headlines of…

  1. Arizona TeleMedicine Network: Engineering Master Plan.

    Science.gov (United States)

    Atlantic Research Corp., Alexandria, VA.

    As the planning document for establishing a statewide health communications system initially servicing the Papago, San Carlos and White Mountain Apache, Navajo, and Hopi reservations, this document prescribes the communications services to be provided by the Arizona TeleMedicine Network. Specifications include: (1) communications services for each…

  2. Arizona Commission of Indian Affairs 1982 Annual Report.

    Science.gov (United States)

    Arizona Commission of Indian Affairs, Phoenix.

    Designed to provide insight into the proceedings, transactions, and findings of the Arizona Commission of Indian Affairs, this 1981-82 annual report reflects the Commission's efforts to improve communications, understanding and working relationships between tribes and state government to provide tribes with technical assistance. The report…

  3. Alternative Fuels Data Center: Arizona Transportation Data for Alternative

    Science.gov (United States)

    Biodiesel (B20 and above) 3 74 Compressed Natural Gas (CNG) 12 17 Electric 399 45 Ethanol (E85) 19 2 Arizona Videos on YouTube Video thumbnail for Phoenix Utility Fleet Drives Smarter with Biodiesel Phoenix Utility Fleet Drives Smarter with Biodiesel Aug. 26, 2017 https://www.youtube.com/embed/4pUL3sb4RA4 Video

  4. Language Ideologies of Arizona Voters, Language Managers, and Teachers

    Science.gov (United States)

    Fitzsimmons-Doolan, Shannon

    2014-01-01

    Arizona is the site of many explicit language policies as well as ongoing scholarly discussions of related language ideologies--beliefs about the role of language in society. This study adds a critical piece to the investigation of the role of ideologies in language policy processes by thoroughly documenting language ideologies expressed by a…

  5. Features of Acquired Immunity in Malaria Endemic Areas

    Indian Academy of Sciences (India)

    ... of Acquired Immunity in Malaria Endemic Areas. Adults (>15 years) do not suffer from the disease. Concomitant presence of low levels of P. falciparum in immune persons. This immunity is lost within 6-12 months if a person moves out of endemic area. Antibodies mediate protection for the asexual stages of P. falciparum.

  6. Seasonal Distribution and Diversity of Ground Arthropods in Microhabitats Following a Shrub Plantation Age Sequence in Desertified Steppe

    Science.gov (United States)

    Liu, Rentao; Zhu, Fan; Song, Naiping; Yang, Xinguo; Chai, Yongqing

    2013-01-01

    In desertified regions, shrub-dominated patches are important microhabitats for ground arthropod assemblages. As shrub age increases, soil, vegetation and microbiological properties can change remarkably and spontaneously across seasons. However, relatively few studies have analyzed how ground arthropods respond to the microhabitats created by shrubs of different plantation ages across seasons. Using 6, 15, 24 and 36 year-old plantations of re-vegetated shrubs (Caragana koushinskii) in the desert steppe of northwestern China as a model system, we sampled ground arthropod communities using a pitfall trapping method in the microhabitats under shrubs and in the open areas between shrubs, during the spring, summer and autumn. The total ground arthropod assemblage was dominated by Carabidae, Melolonthidae, Curculionidae, Tenebrionidae and Formicidae that were affected by plantation age, seasonal changes, or the interaction between these factors, with the later two groups also influenced by microhabitat. Overall, a facilitative effect was observed, with more arthropods and a greater diversity found under shrubs as compared to open areas, but this was markedly affected by seasonal changes. There was a high degree of similarity in arthropod assemblages and diversity between microhabitats in summer and autumn. Shrub plantation age significantly influenced the distribution of the most abundant groups, and also the diversity indices of the ground arthropods. However, there was not an overall positive relationship between shrub age and arthropod abundance, richness or diversity index. The influence of plantation age on arthropod communities was also affected by seasonal changes. From spring through summer to autumn, community indices of ground arthropods tended to decline, and a high degree of similarity in these indices (with fluctuation) was observed among different ages of shrub plantation in autumn. Altogether the recovery of arthropod communities was markedly affected by

  7. The response of Arctic vegetation to the summer climate: relation between shrub cover, NDVI, surface albedo and temperature

    Energy Technology Data Exchange (ETDEWEB)

    Blok, Daan; Heijmans, Monique M P D; Berendse, Frank [Nature Conservation and Plant Ecology Group, Wageningen University, PO Box 47, 6700 AA, Wageningen (Netherlands); Schaepman-Strub, Gabriela [Institute of Evolutionary Biology and Environmental Studies, University of Zuerich, Winterthurerstrasse 190, 8057 Zuerich (Switzerland); Bartholomeus, Harm [Centre for Geo-Information, Wageningen University, PO Box 47, 6700 AA, Wageningen (Netherlands); Maximov, Trofim C, E-mail: daan.blok@wur.nl [Biological Problems of the Cryolithozone, Russian Academy of Sciences, Siberian Division, 41, Lenin Prospekt, Yakutsk, The Republic of Sakha, Yakutia 677980 (Russian Federation)

    2011-07-15

    Recently observed Arctic greening trends from normalized difference vegetation index (NDVI) data suggest that shrub growth is increasing in response to increasing summer temperature. An increase in shrub cover is expected to decrease summer albedo and thus positively feed back to climate warming. However, it is unknown how albedo and NDVI are affected by shrub cover and inter-annual variations in the summer climate. Here, we examine the relationship between deciduous shrub fractional cover, NDVI and albedo using field data collected at a tundra site in NE Siberia. Field data showed that NDVI increased and albedo decreased with increasing deciduous shrub cover. We then selected four Arctic tundra study areas and compiled annual growing season maximum NDVI and minimum albedo maps from MODIS satellite data (2000-10) and related these satellite products to tundra vegetation types (shrub, graminoid, barren and wetland tundra) and regional summer temperature. We observed that maximum NDVI was greatest in shrub tundra and that inter-annual variation was negatively related to summer minimum albedo but showed no consistent relationship with summer temperature. Shrub tundra showed higher albedo than wetland and barren tundra in all four study areas. These results suggest that a northwards shift of shrub tundra might not lead to a decrease in summer minimum albedo during the snow-free season when replacing wetland tundra. A fully integrative study is however needed to link results from satellite data with in situ observations across the Arctic to test the effect of increasing shrub cover on summer albedo in different tundra vegetation types.

  8. Why Be a Shrub? A Basic Model and Hypotheses for the Adaptive Values of a Common Growth Form

    Science.gov (United States)

    Götmark, Frank; Götmark, Elin; Jensen, Anna M.

    2016-01-01

    Shrubs are multi-stemmed short woody plants, more widespread than trees, important in many ecosystems, neglected in ecology compared to herbs and trees, but currently in focus due to their global expansion. We present a novel model based on scaling relationships and four hypotheses to explain the adaptive significance of shrubs, including a review of the literature with a test of one hypothesis. Our model describes advantages for a small shrub compared to a small tree with the same above-ground woody volume, based on larger cross-sectional stem area, larger area of photosynthetic tissue in bark and stem, larger vascular cambium area, larger epidermis (bark) area, and larger area for sprouting, and faster production of twigs and canopy. These components form our Hypothesis 1 that predicts higher growth rate for a small shrub than a small tree. This prediction was supported by available relevant empirical studies (14 publications). Further, a shrub will produce seeds faster than a tree (Hypothesis 2), multiple stems in shrubs insure future survival and growth if one or more stems die (Hypothesis 3), and three structural traits of short shrub stems improve survival compared to tall tree stems (Hypothesis 4)—all hypotheses have some empirical support. Multi-stemmed trees may be distinguished from shrubs by more upright stems, reducing bending moment. Improved understanding of shrubs can clarify their recent expansion on savannas, grasslands, and alpine heaths. More experiments and other empirical studies, followed by more elaborate models, are needed to understand why the shrub growth form is successful in many habitats. PMID:27507981

  9. The response of Arctic vegetation to the summer climate: relation between shrub cover, NDVI, surface albedo and temperature

    International Nuclear Information System (INIS)

    Blok, Daan; Heijmans, Monique M P D; Berendse, Frank; Schaepman-Strub, Gabriela; Bartholomeus, Harm; Maximov, Trofim C

    2011-01-01

    Recently observed Arctic greening trends from normalized difference vegetation index (NDVI) data suggest that shrub growth is increasing in response to increasing summer temperature. An increase in shrub cover is expected to decrease summer albedo and thus positively feed back to climate warming. However, it is unknown how albedo and NDVI are affected by shrub cover and inter-annual variations in the summer climate. Here, we examine the relationship between deciduous shrub fractional cover, NDVI and albedo using field data collected at a tundra site in NE Siberia. Field data showed that NDVI increased and albedo decreased with increasing deciduous shrub cover. We then selected four Arctic tundra study areas and compiled annual growing season maximum NDVI and minimum albedo maps from MODIS satellite data (2000-10) and related these satellite products to tundra vegetation types (shrub, graminoid, barren and wetland tundra) and regional summer temperature. We observed that maximum NDVI was greatest in shrub tundra and that inter-annual variation was negatively related to summer minimum albedo but showed no consistent relationship with summer temperature. Shrub tundra showed higher albedo than wetland and barren tundra in all four study areas. These results suggest that a northwards shift of shrub tundra might not lead to a decrease in summer minimum albedo during the snow-free season when replacing wetland tundra. A fully integrative study is however needed to link results from satellite data with in situ observations across the Arctic to test the effect of increasing shrub cover on summer albedo in different tundra vegetation types.

  10. EFFECTS OF PLANT SIZE ON PHOTOSYNTHESIS AND WATER RELATIONS IN THE DESERT SHRUB PROSOPIS GLANDULOSA (FABACEAE)

    Science.gov (United States)

    The Jornada del Muerto basin of the Chihuahuan Desert of southern New Mexico, USA, has undergone a marked transition of plant communities. Shrubs such as mesquite (Prosopis glandulosa) have greatly increased or now dominate in areas that were previously dominated by perennial gra...

  11. Rapid root extension during water pulses enhances establishment of shrub seedlings in the Atacama Desert

    NARCIS (Netherlands)

    Leon, M.F.; Squeo, F.A.; Gutierrez, J.R.; Holmgren, M.

    2011-01-01

    Questions: (1) What is the water threshold for shrub seedling establishment in arid scrubland? (2) How do seedling root growth morphological traits affect the water threshold required for seedling establishment? Location: Arid scrubland, Atacama Desert, north-central Chile. Methods: We conducted a

  12. Physical characteristics of shrub and conifer fuels for fire behavior models

    Science.gov (United States)

    Jonathan R. Gallacher; Thomas H. Fletcher; Victoria Lansinger; Sydney Hansen; Taylor Ellsworth; David R. Weise

    2017-01-01

    The physical properties and dimensions of foliage are necessary inputs for some fire spread models. Currently, almost no data exist on these plant characteristics to fill this need. In this report, we measured the physical properties and dimensions of the foliage from 10 live shrub and conifer fuels throughout a 1-year period. We developed models to predict relative...

  13. Establishment of trees and shrubs on lands disturbed by mining in the West

    Science.gov (United States)

    Ardell J. Bjugstad

    1984-01-01

    Increased research and development of cultural practices and species has assured success of establishment of trees and shrubs on lands disturbed by surface mining. Trickle irrigation and water harvesting techniques have increased survival of planted stock by 250 percent for some species.

  14. Bayesian estimation of shrubs diversity in rangelands under two management systems in northern Syria

    NARCIS (Netherlands)

    Niane, A.A.; Singh, M.; Struik, P.C.

    2014-01-01

    The diversity of shrubs in rangelands of northern Syria is affected by the grazing management systems restricted by the increase in human and livestock populations. To describe and estimate diversity and compare the rangeland grazing management treatments, two popular indices for diversity, the

  15. Interacting effects of grass height and herbivores on the establishment of an encroaching savanna shrub

    NARCIS (Netherlands)

    Hagenah, N.; Munkert, H.; Gerhardt, K.; Olff, H.

    2009-01-01

    Shrub encroachment is a widely observed problem in Southern African savannas. Although the effects of herbivory and grass height on woody species recruitment have been studied individually, little information exists about how these factors interact. In this study seeds and seedlings of the

  16. Diversity, composition and density of trees and shrubs in agroforestry homegardens in Southern Ethiopia

    NARCIS (Netherlands)

    Abebe, T.; Sterck, F.J.; Wiersum, K.F.; Bongers, F.

    2013-01-01

    Diversity of trees and shrubs in agricultural systems contributes to provision of wood and non-wood products, and protects the environment, thereby, enhancing socioeconomic and ecological sustainability of the systems. This study characterizes the diversity, density and composition of trees in the

  17. Efficacy of exclosures in conserving local shrub biodiversity in xeric sandy grassland, Inner Mongolia, China

    Science.gov (United States)

    Feng-Rui Li; Zhi-Yu Zhou; Li-Ya Zhao; Ai-Sheng Zhang; Ling-Fen Kang

    2007-01-01

    This study investigated the abundance and frequency of occurrence of all shrub species present in the standing vegetation at four sites, including a 5-year exclosure (protected grassland) and three adjacent unprotected grazing sites that had been subjected to different levels of degradation (light, moderate and severe), in xeric sandy grassland of Inner Mongolia for...

  18. Similar tree seedling responses to shrubs and to simulated environmental changes at Pyrenean and subarctic treelines.

    NARCIS (Netherlands)

    Grau, O.; Ninot, J.M.; Cornelissen, J.H.C.; Callaghan, T.V.

    2013-01-01

    Background: Climate, land-use and disturbance regimes are key drivers of treeline dynamics worldwide, but local and regional spatio-temporal patterns indicate that additional factors play an important role. Some studies suggest that shrub-tree interactions control tree seedling recruitment patterns

  19. Natural polyploidization within tetraploid and hexaploid populations of the desert shrub Atriplex confertifolia

    Science.gov (United States)

    Stewart C. Sanderson

    2011-01-01

    Shadscale (Atriplex confertifolia) is a wind-pollinated dioecious shrub of western North America with an unusual development of apparently autoploid races, showing all even ploidy levels from 2x to 12x (base x = 9). Of these, tetraploid races are the most frequently encountered, with octoploids the next most common, and hexaploids being much less common. In this study...

  20. Age and distribution of an evergreen clonal shrub in the Coweeta basin: Rhododendron maximum L

    Science.gov (United States)

    Katherine J. Elliott; James M. Vose

    2012-01-01

    Rhododendron maximum L. is an evergreen, clonal shrub that forms a dominant sub-canopy layer and is a key species in southern Appalachian forests. We investigated the age and distribution of R. maximum across the Coweeta Basin, a 1626 ha watershed in western North Carolina. We selected 16 perennial, second-order streams and used a Global Positioning System to establish...

  1. Targeted grazing for the restoration of sub-alpine shrub-encroached grasslands

    Directory of Open Access Journals (Sweden)

    Massimiliano Probo

    2016-12-01

    Full Text Available The decline of agro-pastoral activities has led to a widespread tree and shrub-encroachment of former semi-natural meso-eutrophic grasslands in many European mountain regions. Temporary night camp areas (TNCA and mineral mix supplements for targeted cattle were arranged over shrub-encroached areas to restore grassland vegetation within the Val Troncea Natural Park (Italy. From 2011 to 2015, their effects on vegetation structure and pastoral value of forage were assessed along permanent transects. Four years after treatments, both practices were effective in reducing the shrub cover and increasing the cover and average height of the herbaceous layer, but changes were more remarkable within TNCA. Moreover, the arrangement of TNCA decreased the cover of nanophanerophytes and increased the cover of graminoids and high quality species, as well as the overall forage pastoral value. In conclusion, TNCA were the most effective pastoral practice to contrast shrub-encroachment and increase herbage mass and forage quality of sub-alpine grasslands.

  2. Removing an exotic shrub from riparian forests increases butterfly abundance and diversity

    Science.gov (United States)

    James Hanula; Scott Horn

    2011-01-01

    Invasive plants are one of the greatest threats to endangered insect species and a major threat to Lepidoptera in eastern North America. We investigated the effects of the invasive shrub Chinese privet (Ligustrum sinense) and two methods (mulching or hand-felling) of removing it from riparian forests on butterfly communities and compared them to untreated, heavily...

  3. Possibilities of cultivating ornamental trees and shrubs under conditions of air pollution with oxides of sulfur

    Energy Technology Data Exchange (ETDEWEB)

    Bialobok, S.; Bartkowiak, S.; Rachwal, L.

    1974-01-01

    The field work conducted has shown that high concentrations of SO/sub 2/ in the air can be withstood by the following trees and shrubs. Trees: Acer campestris, A. platanoides, Ailanthus altissima, Aesculus hippocastanum, Morus alba, Platanus acerifolia, Pinus strobur, P. nigra, Populus Berolinensis, P. candicans, P. Hybr. 27, P. Marilandica, P. simonii, P. Serotina, Quercus robus, Robinia pseudoacacia. Shrubs: Caragana arborescens, Crataegus oxyacantha, C. monogyna, Cerasus mehaleb, Forsythia/most of the species and varieties/, Ligustrum vulgare, Philadelphus coronaria, Ptelea trifoliata, Sambucus nigra, Salix caprea, Sorbaria sorbifolia, Sorbus aucuparia, Taxus baccata. For the selection of trees and shrubs in the laboratory, high concentrations of SO/sub 2/ were used (60-150 ppm for a period of 10 minutes). Experiments were conducted on cut shrubs kept in the gas chambers. In order to estimate the degree of their injury, they were transferred to a shaded greenhouse. A concentration of 65 ppm of SO/sub 2/ could be withstood by the following Forsythias: Forsythia intermedia Primulina, F. Densiflora, F. Spectabilis, F. giraldina, F. suspensa, F. koreana, F. ovata, F. japonica and Hippophae rhamnoides. A concentration of 130 ppm could be withstood only by F. intermedia Vitelina. A similarly high concentration of SO/sub 2/ could be withstood by shoots and leaves of Ailanthus girladii Duclouxii and by Platanus acerifolia. From among the lilacs Syringa pekinensis and S. amurensis proved resistant to high concentrations of SO/sub 2/.

  4. Trophic cascades: linking ungulates to shrub-dependent birds and butterflies.

    Science.gov (United States)

    J Teichman, Kristine; Nielsen, Scott E; Roland, Jens

    2013-11-01

    1. Studies demonstrating trophic cascades through the loss of top-down regulatory processes in productive and biologically diverse terrestrial ecosystems are limited. 2. Elk Island National Park, Alberta and surrounding protected areas have a wide range of ungulate density due to the functional loss of top predators, management for high ungulate numbers and variable hunting pressure. This provides an ideal setting for studying the effects of hyper-abundant ungulates on vegetation and shrub-dependent bird and butterfly species. 3. To examine the cascading effects of high ungulate density, we quantified vegetation characteristics and abundances of yellow warbler Dendroica petechia and Canadian tiger swallowtail Papilio canadensis under different ungulate density in and around Elk Island National Park. 4. Using Structural Equation Models we found that ungulate density was inversely related to shrub cover, whereas shrub cover was positively related to yellow warbler abundance. In addition, chokecherry Prunus virginiana abundance was inversely related to browse impact but positively related to P. canadensis abundance. 5. These results demonstrate a cascade resulting from hyper-abundant ungulates on yellow warblers and Canadian tiger swallowtails through reductions in shrub cover and larval host plant density. The combined effect of the functional loss of top predators and management strategies that maintain high ungulate numbers can decouple top-down regulation of productive temperate ecosystems. © 2013 The Authors. Journal of Animal Ecology © 2013 British Ecological Society.

  5. Soil carbon dioxide (CO 2 ) efflux of two shrubs in response to plant ...

    African Journals Online (AJOL)

    Although plant density should affect soil carbon dioxide (CO2) efflux and carbon cycling in semi-arid regions, the effects of plant density on soil CO2 efflux are not well known. This study was performed to investigate the responses of soil CO2 efflux of two dominant shrubs (Caragana korshinkii and Salix psammophila) to ...

  6. Antecedent conditions influence soil respiration differences in shrub and grass patches

    Science.gov (United States)

    Quantifying the response of soil respiration to past environmental conditions is critical for predicting how future climate and vegetation change will impact ecosystem carbon balance. Increased shrub dominance in semiarid grasslands has potentially large effects on soil carbon cycling. The goal of t...

  7. Evaluation and prediction of shrub cover in coastal Oregon forests (USA)

    Science.gov (United States)

    Becky K. Kerns; Janet L. Ohmann

    2004-01-01

    We used data from regional forest inventories and research programs, coupled with mapped climatic and topographic information, to explore relationships and develop multiple linear regression (MLR) and regression tree models for total and deciduous shrub cover in the Oregon coastal province. Results from both types of models indicate that forest structure variables were...

  8. State-space modeling indicates rapid invasion of an alien shrub in coastal dunes

    DEFF Research Database (Denmark)

    Damgaard, Christian Frølund; Nygaard, Bettina; Ejrnæs, Rasmus

    2011-01-01

    allows separation of process and sampling variance, thus enabling ecological predictions with a known degree of uncertainty. The method is applied for the invasive shrub Rosa rugosa (Japanese rose) in Danish fixed dunes. The probability of observing R. rugosa increased significantly from 0.18 to 0...

  9. Influence of shrub cover vegetal and slope length on soil bulk density

    International Nuclear Information System (INIS)

    Bienes, R.; Jimenez, R.; Ruiz, M.; Garcia-Estringana, P.; Marques, M. J.

    2009-01-01

    In arid and semiarid environments of the Mediterranean climate, the shrub species play an important role in the revegetation of abandoned lands, which enables to control the soil losses, organic material and water. In this article are compared the results obtained under different revegetation in abandoned lands in the central area of Spain. In these revegetation has been used two native shrubs: A triplex halimus (Ah) and Retama sphaerocarpa (Rs), and were analyzed the influence of these revegetation in the contents of organic material of soil and apparent density in 5 years time after planting. As control, have been considered the pieces of ground with spontaneous vegetation abandoned in the same date that the shrubs revegetation. Atriplex halimus gives to the soil a covering capable to intercept a big amount of water drops absorbing a great amount part of the kinetic energy of the rain, while provides a microclimates as a result of be able to soften the wind, the temperature and the evaporation-transpiration, which makes it efficient to control the erosion and the desertification (Le Houerou, 2000). Retama sphaerocarpa was chosen because it is a native shrub very characteristic, and, due to its symbiosis with the Bradyrhizobium, enriches the soil in nitrogen, which is taken by the nitrophilous species enhancing the spontaneous vegetal covering. (Author) 9 refs.

  10. Guide to insect borers in North American broadleaf trees and shrubs

    Science.gov (United States)

    J.D. Solomon

    1995-01-01

    This book is an illustrated guide to 300 species of inset borers that attack hardwood trees, shrubs, and other woody angiosperms in North America. The major purposes of this guide are to identify insect borers and theri damage to provide information for controlling them. Readers most likely to find this guide useful are practiving foresters, entomologists, and others...

  11. Shrub removal in reforested post-fire areas increases native plant species richness

    Science.gov (United States)

    Gabrielle N. Bohlman; Malcolm North; Hugh D. Safford

    2016-01-01

    Large, high severity fires are becoming more prevalent in Sierra Nevada mixed-conifer forests, largely due to heavy fuel loading and forest densification caused by past and current management practices. In post-fire areas distant from seed trees, conifers are often planted to re-establish a forest and to prevent a potential type-conversion to shrub fields. Typical...

  12. Insects and Related Pests of Trees, Shrubs, and Lawns. MP-25R.

    Science.gov (United States)

    Spackman, Everett W.; Lawson, Fred A.

    This document discusses identification and control of the pests of trees and shrubs. The insects are grouped according to feeding habits and the type of damage caused to plants. Categories include the sucking insects and mites, leaf eating insects, pests attacking trunks and branches, and gall causing insects. (CS)

  13. Which shrubs and trees can conserve natural enemies of aphids in spring?

    NARCIS (Netherlands)

    van Rijn, P.C.J.

    2014-01-01

    Habitats with shrubs and trees within the agricultural landscape may contribute to the maintenance of natural enemies of pests. Aphids and flowers are important resources for beneficial natural enemies such as ladybeetles, hoverflies and lacewings. Woody plants are the most likely candidates to

  14. Nitrogen-addition effects on leaf traits and photosynthetic carbon gain of boreal forest understory shrubs.

    Science.gov (United States)

    Palmroth, Sari; Bach, Lisbet Holm; Nordin, Annika; Palmqvist, Kristin

    2014-06-01

    Boreal coniferous forests are characterized by fairly open canopies where understory vegetation is an important component of ecosystem C and N cycling. We used an ecophysiological approach to study the effects of N additions on uptake and partitioning of C and N in two dominant understory shrubs: deciduous Vaccinium myrtillus in a Picea abies stand and evergreen Vaccinium vitis-idaea in a Pinus sylvestris stand in northern Sweden. N was added to these stands for 16 and 8 years, respectively, at rates of 0, 12.5, and 50 kg N ha(-1) year(-1). N addition at the highest rate increased foliar N and chlorophyll concentrations in both understory species. Canopy cover of P. abies also increased, decreasing light availability and leaf mass per area of V. myrtillus. Among leaves of either shrub, foliar N content did not explain variation in light-saturated CO2 exchange rates. Instead photosynthetic capacity varied with stomatal conductance possibly reflecting plant hydraulic properties and within-site variation in water availability. Moreover, likely due to increased shading under P. abies and due to water limitations in the sandy soil under P. sylvestris, individuals of the two shrubs did not increase their biomass or shift their allocation between above- and belowground parts in response to N additions. Altogether, our results indicate that the understory shrubs in these systems show little response to N additions in terms of photosynthetic physiology or growth and that changes in their performance are mostly associated with responses of the tree canopy.

  15. Seed germination methods for native Caribbean trees and shrubs : with emphasis on species relevant for Bonaire

    NARCIS (Netherlands)

    Burg, van der W.J.; Freitas, J.; Debrot, A.O.

    2014-01-01

    This paper is intended as a basis for nature restoration activities using seeds of trees and (larger) shrubs native to Bonaire with the aim of reforestation. It describes the main seed biology issues relevant for species from this region, to facilitate decisions on time and stage of harvesting, safe

  16. Facilitation of Quercus ilex recruitment by shrubs in Mediterranean open woodlands

    NARCIS (Netherlands)

    Smit, Christian; den Ouden, Jan; Diaz, Mario

    Question: Insufficient tree regeneration threatens the long-term persistence of biodiverse Mediterranean open oak woodlands. Could shrubs, scarce due to decades of management ( clearing and ploughing), facilitate holm oak recruitment at both acorn and seedling stages? Location: Open oak woodlands in

  17. Facilitation of Quercus ilex recruitment by shrubs in Mediterranean open woodlands

    NARCIS (Netherlands)

    Smit, C.; Ouden, den J.; Diaz, M.

    2008-01-01

    Question: Insufficient tree regeneration threatens the long-term persistence of biodiverse Mediterranean open oak woodlands. Could shrubs, scarce due to decades of management (clearing and ploughing), facilitate holm oak recruitment at both acorn and seedling stages? Location: Open oak woodlands in

  18. Diseases of Ornamental and Shade Trees, Shrubs, Vines, and Ground Covers.

    Science.gov (United States)

    Nichols, Lester P.

    This agriculture extension service publication from Pennsylvania State University covers the identification and control of common ornamental trees, shrubs, and ground cover diseases. The publication is divided into sections. The first section discusses the diseases of ornamental and shade trees, including general diseases and diseases of specific…

  19. Community structure affects annual grass weed invasion during restoration of a shrub-steppe ecosystem

    Science.gov (United States)

    Phil S. Allen; Susan E. Meyer

    2014-01-01

    Ecological restoration of shrub-steppe communities in the western United States is often hampered by invasion of exotic annual grasses during the process. An important question is how to create restored communities that can better resist reinvasion by these weeds. One hypothesis is that communities comprised of species that are functionally similar to the invader will...

  20. Spacing and shrub competition influence 20-year development of planted ponderosa pine

    Science.gov (United States)

    William W. Oliver

    1990-01-01

    Growth and stand development of ponderosa pine (Pinus ponderosa) were monitored for 20 years after planting at five different square spacings (6, 9, 12, 15, and 18 ft) in the presence or absence of competing shrubs on the westside Sierra Nevada. Mean tree size was positively correlated and stand values negatively correlated with spacing in the...

  1. Tree and shrub species integration in the crop-livestock farming ...

    African Journals Online (AJOL)

    Tree and shrub integration has been promoted as a means of enhancing rural livelihoods through sustaining watershed provision of services and products, especially in Ethiopia. However, research to support this effort has been limited. This study was conducted in Borodo watershed in central Ethiopia, to identify ...

  2. Judicial Performance Review in Arizona: A Critical Assessment

    Directory of Open Access Journals (Sweden)

    Rebecca White Berch

    2014-12-01

    Full Text Available Judicial performance evaluations are a relatively new tool for assessing judges and providing information to voters to help them determine whether to retain judges in contested or retention elections. Arizona implemented its judicial evaluation program about 20 years ago, and since that time, the state has continually strived to improve its process. The result is that today Arizona has one of the most progressive and comprehensive judicial performance evaluation programs in the United States. This article takes a critical look at the strengths and weaknesses of Arizona’s program, keeping in mind two key values that the system seeks to protect: judicial accountability and judicial independence. Las evaluaciones del rendimiento judicial son una herramienta relativamente nueva para evaluar a los jueces y ofrecer información a los votantes, que les ayude a decidir si quieren reelegir a los jueces en las elecciones. Arizona implementó su programa de evaluación judicial hace unos 20 años, y desde ese momento, el Estado se ha esforzado continuamente en mejorar el proceso. El resultado es que hoy en día, Arizona tiene uno de los programas de evaluación del rendimiento judicial más progresistas e integrales de los Estados Unidos. Este artículo ofrece una mirada crítica a las fortalezas y debilidades del programa de Arizona, teniendo en cuenta dos valores clave que el sistema trata de proteger: la responsabilidad judicial y la independencia judicial. DOWNLOAD THIS PAPER FROM SSRN: http://ssrn.com/abstract=2533868

  3. Endemic earthworms (Oligochaeta: Lumbricidae) of the Balkan Peninsula: a review.

    Science.gov (United States)

    Trakić, Tanja; Valchovski, Hristo; Stojanović, Mirjana

    2016-11-10

    A list of the endemic earthworms of the Balkan Peninsula is presented. Comprehensive information on the ecology, distribution on the Balkan Peninsula and zoogeographical type of all endemics is given. The list comprises 90 species and subspecies, belonging to 11 genera of the family Lumbricidae. The largest number of the Balkan endemic earthworms belongs to a narrow range group (63.3%). Broad range endemic species take part with 36.7%. Our study shows that the degree of endemism on the Balkan Peninsula is extremely high (about 40%) suggesting an important process of autochthonous speciation on the Balkan Peninsula. This appearance is attributable to relative isolation of the mountains compared to the lowlands within the context of paleoenvironmental changes.

  4. Automated classification of tropical shrub species: a hybrid of leaf shape and machine learning approach.

    Science.gov (United States)

    Murat, Miraemiliana; Chang, Siow-Wee; Abu, Arpah; Yap, Hwa Jen; Yong, Kien-Thai

    2017-01-01

    Plants play a crucial role in foodstuff, medicine, industry, and environmental protection. The skill of recognising plants is very important in some applications, including conservation of endangered species and rehabilitation of lands after mining activities. However, it is a difficult task to identify plant species because it requires specialized knowledge. Developing an automated classification system for plant species is necessary and valuable since it can help specialists as well as the public in identifying plant species easily. Shape descriptors were applied on the myDAUN dataset that contains 45 tropical shrub species collected from the University of Malaya (UM), Malaysia. Based on literature review, this is the first study in the development of tropical shrub species image dataset and classification using a hybrid of leaf shape and machine learning approach. Four types of shape descriptors were used in this study namely morphological shape descriptors (MSD), Histogram of Oriented Gradients (HOG), Hu invariant moments (Hu) and Zernike moments (ZM). Single descriptor, as well as the combination of hybrid descriptors were tested and compared. The tropical shrub species are classified using six different classifiers, which are artificial neural network (ANN), random forest (RF), support vector machine (SVM), k-nearest neighbour (k-NN), linear discriminant analysis (LDA) and directed acyclic graph multiclass least squares twin support vector machine (DAG MLSTSVM). In addition, three types of feature selection methods were tested in the myDAUN dataset, Relief, Correlation-based feature selection (CFS) and Pearson's coefficient correlation (PCC). The well-known Flavia dataset and Swedish Leaf dataset were used as the validation dataset on the proposed methods. The results showed that the hybrid of all descriptors of ANN outperformed the other classifiers with an average classification accuracy of 98.23% for the myDAUN dataset, 95.25% for the Flavia dataset and 99

  5. Spreaders, igniters, and burning shrubs: plant flammability explains novel fire dynamics in grass-invaded deserts.

    Science.gov (United States)

    Fuentes-Ramirez, Andres; Veldman, Joseph W; Holzapfel, Claus; Moloney, Kirk A

    2016-10-01

    Novel fire regimes are an important cause and consequence of global environmental change that involve interactions among biotic, climatic, and human components of ecosystems. Plant flammability is key to these interactions, yet few studies directly measure flammability or consider how multiple species with different flammabilities interact to produce novel fire regimes. Deserts of the southwestern United States are an ideal system for exploring how novel fire regimes can emerge when fire-promoting species invade ecosystems comprised of species that did not evolve with fire. In these deserts, exotic annual grasses provide fuel continuity across landscapes that did not historically burn. These fires often ignite a keystone desert shrub, the fire-intolerant creosote bush, Larrea tridentata (DC.) Coville. Ignition of Larrea is likely catalyzed by fuels produced by native plants that grow beneath the shrubs. We hypothesize that invasive and native species exhibit distinct flammability characteristics that in combination determine spatial patterns of fire spread and intensity. We measured flammability metrics of Larrea, two invasive grasses, Schismus arabicus and Bromus madritensis, and two native plants, the sub-shrub Ambrosia dumosa and the annual herb Amsinckia menziesii. Results of laboratory experiments show that the grasses carry fire quickly (1.32 cm/s), but burn for short duration (0.5 min) at low temperatures. In contrast, native plants spread fire slowly (0.12 cm/s), but burn up to eight times longer (4 min) and produced hotter fires. Additional experiments on the ignition requirements of Larrea suggest that native plants burn with sufficient temperature and duration to ignite dead Larrea branches (time to ignition, 2 min; temperature at ignition 692°C). Once burning, these dead branches ignite living branches in the upper portions of the shrub. Our study provides support for a conceptual model in which exotic grasses are "spreaders" of fire and native

  6. Responses of nocturnal rodents to shrub encroachment in Banni grasslands, Gujarat, India

    Science.gov (United States)

    Jayadevan, A.

    2016-12-01

    Shrub encroachment is one of the greatest threats to grasslands globally. These woodlands can strongly influence the behaviour of small mammals adapted to more open habitats, which rely on high visibility for early detection of predators. In semi-arid grasslands, rodents are considered keystone species. Although shrub encroachment is known to negatively affect rodent assemblages, its impact on the foraging behaviour of rodents, which is known to vary in response to risky situations, is unknown. Understanding whether shrub encroachment alters such antipredator behaviour is important as antipredator behaviour can alter the distribution, abundance and ultimately, survival of prey species. In this study, I explored the effects of shrub encroachment on the foraging behaviour of nocturnal rodent communities in the Banni grasslands, India. I examined foraging behaviour, quantified using the giving-up density (GUD) framework and the number of rodent crossings around food patches, in two habitats that differed in the extent of shrub encroachment. Under the GUD framework, the amount of food left behind by a forager in a food patch reflects the costs of feeding at the patch. Higher GUDs imply higher foraging costs. I also investigated how removal of an invasive woody plant, Prosopis juliflora would affect foraging behaviour of nocturnal rodents. High shrub encroachment was associated with higher foraging costs (higher GUDs) and lower activity than the sparsely wooded habitat, likely due to low visibility in the densely wooded habitat. The dense habitat also supported a higher richness and relative abundance of generalist rodents than the sparse habitat, likely due to the increased heterogeneity of the habitat. The tree removal experiment revealed that rodents had lower GUDs (i.e., low foraging costs) after the event of tree cutting. This may be due to the reduction of cover in the habitat, leading to higher visibility and lower predation risk. My results suggest that shrub

  7. Endemism hotspots are linked to stable climatic refugia.

    Science.gov (United States)

    Harrison, Susan; Noss, Reed

    2017-01-01

    Centres of endemism have received much attention from evolutionists, biogeographers, ecologists and conservationists. Climatic stability is often cited as a major reason for the occurrences of these geographic concentrations of species which are not found anywhere else. The proposed linkage between endemism and climatic stability raises unanswered questions about the persistence of biodiversity during the present era of rapidly changing climate. The current status of evidence linking geographic centres of endemism to climatic stability over evolutionary time was examined. The following questions were asked. Do macroecological analyses support such an endemism-stability linkage? Do comparative studies find that endemic species display traits reflecting evolution in stable climates? Will centres of endemism in microrefugia or macrorefugia remain relatively stable and capable of supporting high biological diversity into the future? What are the implications of the endemism-stability linkage for conservation? Recent work using the concept of climate change velocity supports the classic idea that centres of endemism occur where past climatic fluctuations have been mild and where mountainous topography or favourable ocean currents contribute to creating refugia. Our knowledge of trait differences between narrow endemics and more widely distributed species remains highly incomplete. Current knowledge suggests that centres of endemism will remain relatively climatically buffered in the future, with the important caveat that absolute levels of climatic change and species losses in these regions may still be large. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Shrub mound formation and stability on semi-arid slopes in the Northern Negev Desert of Israel: A field and simulation study

    NARCIS (Netherlands)

    Buis, E.; Temme, A.J.A.M.; Veldkamp, A.; Boeken, B.; Jongmans, A.G.; Breemen, van N.; Schoorl, J.M.

    2010-01-01

    In semi-arid areas vegetation is scarce and often dominated by individual shrubs on raised mounds. The processes of formation of these mounds are diverse and still debated. Often, shrub mound formation is directly related to the formation of vegetation patterns, thereby assuming that shrub mound

  9. Spatial and temporal patterns of water availability in a grass-shrub ecotone and implications for grassland recovery in arid environments

    Science.gov (United States)

    Encroachment of woody shrubs into historic desert grasslands is a major problem throughout the world. Conversion of grasslands to shrub-dominated systems may result in significant alteration of biogeochemical processes and reduced resource availability in shrub interspaces, making grassland recover...

  10. Resource-use efficiencies of three indigenous tree species planted in resource islands created by shrubs: implications for reforestation of subtropical degraded shrublands

    Science.gov (United States)

    Nan Liu; Qinfeng Guo

    2012-01-01

    Shrub resource islands are characterized by resources accumulated shrubby areas surrounded by relative barren soils. This research aims to determine resource-use efficiency of native trees species planted on shrub resource islands, and to determine how the planted trees may influence the resource islands in degraded shrublands in South China. Shrub (Rhodomyrtus...

  11. Surviving in mountain climate refugia: new insights from the genetic diversity and structure of the relict shrub Myrtus nivellei (Myrtaceae in the Sahara Desert.

    Directory of Open Access Journals (Sweden)

    Jérémy Migliore

    Full Text Available The identification of past glacial refugia has become a key topic for conservation under environmental change, since they contribute importantly to shaping current patterns of biodiversity. However, little attention has been paid so far to interglacial refugia despite their key role for the survival of relict species currently occurring in climate refugia. Here, we focus on the genetic consequences of range contraction on the relict populations of the evergreen shrub Myrtus nivellei, endemic in the Saharan mountains since at least the end of the last Green Sahara period, around 5.5 ka B.P. Multilocus genotypes (nuclear microsatellites and AFLP were obtained from 215 individuals collected from 23 wadis (temporary rivers in the three main mountain ranges in southern Algeria (the Hoggar, Tassili n'Ajjer and Tassili n'Immidir ranges. Identical genotypes were found in several plants growing far apart within the same wadis, a pattern taken as evidence of clonality. Multivariate analyses and Bayesian clustering revealed that genetic diversity was mainly structured among the mountain ranges, while low isolation by distance was observed within each mountain range. The range contraction induced by the last episode of aridification has likely increased the genetic isolation of the populations of M. nivellei, without greatly affecting the genetic diversity of the species as a whole. The pattern of genetic diversity observed here suggests that high connectivity may have prevailed during humid periods, which is consistent with recent paleoenvironmental reconstructions.

  12. Surviving in mountain climate refugia: new insights from the genetic diversity and structure of the relict shrub Myrtus nivellei (Myrtaceae) in the Sahara Desert.

    Science.gov (United States)

    Migliore, Jérémy; Baumel, Alex; Juin, Marianick; Fady, Bruno; Roig, Anne; Duong, Nathalie; Médail, Frédéric

    2013-01-01

    The identification of past glacial refugia has become a key topic for conservation under environmental change, since they contribute importantly to shaping current patterns of biodiversity. However, little attention has been paid so far to interglacial refugia despite their key role for the survival of relict species currently occurring in climate refugia. Here, we focus on the genetic consequences of range contraction on the relict populations of the evergreen shrub Myrtus nivellei, endemic in the Saharan mountains since at least the end of the last Green Sahara period, around 5.5 ka B.P. Multilocus genotypes (nuclear microsatellites and AFLP) were obtained from 215 individuals collected from 23 wadis (temporary rivers) in the three main mountain ranges in southern Algeria (the Hoggar, Tassili n'Ajjer and Tassili n'Immidir ranges). Identical genotypes were found in several plants growing far apart within the same wadis, a pattern taken as evidence of clonality. Multivariate analyses and Bayesian clustering revealed that genetic diversity was mainly structured among the mountain ranges, while low isolation by distance was observed within each mountain range. The range contraction induced by the last episode of aridification has likely increased the genetic isolation of the populations of M. nivellei, without greatly affecting the genetic diversity of the species as a whole. The pattern of genetic diversity observed here suggests that high connectivity may have prevailed during humid periods, which is consistent with recent paleoenvironmental reconstructions.

  13. Living with aliens: effects of invasive shrub honeysuckles on avian nesting.

    Directory of Open Access Journals (Sweden)

    Jason M Gleditsch

    Full Text Available Invasive species have come to the forefront of conservation biology as a major threat to native biodiversity. Habitats dominated by shrub honeysuckles (Lonicera spp. in the United States have been characterized as "ecological traps" by ecologists. Here we tested this hypothesis by investigating the effects of shrub honeysuckles on the nesting ecology of native birds in seven study sites in central Pennsylvania, USA. We examined how the abundance of shrub honeysuckles influenced the selection of nesting substrates and habitat for a community of common songbirds, and the parental-care behavior and nestling development of gray catbirds (Dumetella carolinensis. We found that birds had a strong bias towards nesting in honeysuckle shrubs, but not necessarily for nesting in honeysuckle-dominated habitats. Nest predation rates were affected by the density of nests in a habitat, but not by the overall abundance of honeysuckles in such habitats. Honeysuckle abundance in the habitat did show significant effects on some parental-care behavioral parameters: catbirds had higher nest visitation rates and shorter visit lengths in areas of high honeysuckle density. On average, Gray catbirds fed fruit 12%±0.31 s.e. of their nestling-feeding bouts, mostly fruits of shrub honeysuckles. Nestlings in sites with high honeysuckle density also showed higher mass:tarsus ratios, suggesting a good (possibly better physiological condition of catbird nestlings at the time of fledging. Our study shows that honeysuckle-dominated habitats could have equivocal effects on nesting parameters of common species of native birds. We advise more caution in the widespread denomination of novel plant communities with high densities of honeysuckle as "ecological traps" as effects can be null or positive on native birds in certain localities.

  14. Plant-soil interactions promote co-occurrence of three nonnative woody shrubs.

    Science.gov (United States)

    Kuebbing, Sara E; Classen, Aimée T; Call, Jaime J; Henning, Jeremiah A; Simberloff, Daniel

    2015-08-01

    Ecosystems containing multiple nonnative plant species are common, but mechanisms promoting their co-occurrence are understudied. Plant-soil interactions contribute to the dominance of singleton species in nonnative ranges because many nonnatives experience stronger positive feedbacks relative to co-occurring natives. Plant-soil interactions could impede other nonnatives if an individual nonnative benefits from its soil community to a greater extent than its neighboring nonnatives, as is seen with natives. However, plant-soil interactions could promote nonnative co-occurrence if a nonnative accumulates beneficial soil mutualists that also assist other nonnatives. Here, we use greenhouse and field experiments to ask whether plant-soil interactions (1) promote the codominance of two common nonnative shrubs (Ligustrum sinense and Lonicera maackii) and (2) facilitate the invasion of a less-common nonnative shrub (Rhamnus davurica) in deciduous forests of the southeastern United States. In the greenhouse, we found that two of the nonnatives, L. maackii and R. davurica, performed better in soils conditioned by nonnative shrubs compared to uninvaded forest soils, which. suggests that positive feedbacks among co-occurring nonnative shrubs can promote continued invasion of a site. In both greenhouse and field experiments, we found consistent signals that the codominance of the nonnatives L. sinense and L. maackii may be at least partially explained by the increased growth of L. sinense in L. maackii soils. Overall, significant effects of plant-soil interactions on shrub performance indicate that plant-soil interactions can potentially structure the co-occurrence patterns of these nonnatives.

  15. Is the WBE model appropriate for semi-arid shrubs subjected to clear cutting?

    Science.gov (United States)

    Issoufou, Hassane Bil-Assanou; Rambal, Serge; Le Dantec, Valérie; Oï, Monique; Laurent, Jean-Paul; Saadou, Mahamane; Seghieri, Josiane

    2015-02-01

    It is crucial to understand the adaptive mechanisms of woody plants facing periodic drought to assess their vulnerability to the increasing climate variability predicted in the Sahel. Guiera senegalensis J.F.Gmel is a semi-evergreen Combretaceae commonly found in Sahelian rangelands, fallows and crop fields because of its value as an agroforestry species. We compared canopy leafing, and allometric measurements of leaf area, stem area and stem length and their relationships with leaf water potential, stomatal conductance (gs) and soil-to-leaf hydraulic conductance (KS-L), in mature and current-year resprouts of G. senegalensis in Sahelian Niger. In mature shrubs, seasonal drought reduced the ratio of leaf area to cross-sectional stem area (AL : AS), mainly due to leaf shedding. The canopy of the current-year resprouts remained permanently leafed as the shrubs produced leaves and stems continuously, and their AL : AS ratio increased throughout the dry season. Their KS-L increased, whereas gs decreased. West, Brown and Enquist's (WBE) model can thus describe allometric trends in the seasonal life cycle of undisturbed mature shrubs, but not that of resprouts. Annual clear cutting drives allometric scaling relationships away from theoretical WBE predictions in the current-year resprouts, with scaling exponents 2.5 times greater than those of mature shrubs. High KS-L (twice that of mature shrubs) supports this intensive regeneration process. The adaptive strategy described here is probably common to many woody species that have to cope with both severe seasonal drought and regular disturbance over the long term. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. The evolution of dwarf shrubs in alpine environments: a case study of Alchemilla in Africa.

    Science.gov (United States)

    Gehrke, Berit; Kandziora, Martha; Pirie, Michael D

    2016-01-01

    Alpine and arctic environments worldwide, including high mountains, are dominated by short-stature woody plants (dwarf shrubs). This conspicuous life form asserts considerable influence on local environmental conditions above the treeline, creating its own microhabitat. This study reconstructs the evolution of dwarf shrubs in Alchemilla in the African tropical alpine environment, where they represent one of the largest clades and are among the most common and abundant plants. Different phylogenetic inference methods were used with plastid and nuclear DNA sequence markers, molecular dating (BEAST and RelTime), analyses of diversification rate shifts (MEDUSA and BAMM) and ancestral character and area reconstructions (Mesquite). It is inferred that African Alchemilla species originated following long-distance dispersal to tropical East Africa, but that the evolution of dwarf shrubs occurred in Ethiopia and in tropical East Africa independently. Establishing a timeframe is challenging given inconsistencies in age estimates, but it seems likely that they originated in the Pleistocene, or at the earliest in the late Miocene. The adaptation to alpine-like environments in the form of dwarf shrubs has apparently not led to enhanced diversification rates. Ancestral reconstructions indicate reversals in Alchemilla from plants with a woody base to entirely herbaceous forms, a transition that is rarely reported in angiosperms. Alchemilla is a clear example of in situ tropical alpine speciation. The dwarf shrub life form typical of African Alchemilla has evolved twice independently, further indicating its selective advantage in these harsh environments. However, it has not influenced diversification, which, although recent, was not rapid. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. Are biological effects of desert shrubs more important than physical effects on soil microorganisms?

    Science.gov (United States)

    Berg, Naama; Steinberger, Yosef

    2010-01-01

    Vegetation cover plays a major role in providing organic matter and in acting as a physical barrier, with both together contributing to the formation of "fertile islands," which play an active role in prolonging biological activity in desert ecosystems. By undertaking this study, a longterm research, we designed an experiment to separate the two components-the physical and biotic parts of the perennial plants-and to identify the factor that contributes the most to the ecosystem. The study site was located in the northern Negev Desert, Israel, where 50 Hammada scoparia shrubs and 50 artificial plants were randomly marked. Soil samples were collected monthly over 3 years of research at three locations: under the canopy of H. scoparia shrubs, in the vicinity of the artificial plants, and between the shrubs (control). The contribution to microbial activity was measured by evaluation of the microbial community functions in soil. The functional aspects of the microbial community that were measured were CO2 evolution, microbial biomass, microbial functional diversity, and the physiological profile of the community. The results of this study are presented in two ways: (1) according to the three locations/treatments; and (2) according to the phenological situation of the vegetation (annual and perennial plants) in the research field: the growing phase, the drying process, and the absence of annual plants. The only parameters that were found to affect microbial activity were the contribution of the organic matter of perennial shrubs and the growth of vegetation (annual and perennial) during the growing seasons. The physical component was found to have no effect on soil microbial functional diversity, which elucidates the important contribution of the desert shrub in enhancing biological multiplicity and activity.

  18. Summer warming and changes in snow depth is reflected in the growth rings of Alaskan tundra shrubs (Toolik Lake)

    Science.gov (United States)

    Buchwal, A.; Welker, J. M.

    2016-12-01

    Arctic change is being manifested by shifts in the vegetation composition and abundance throughout many regions of the Arctic. These changes are primarily reflected by increases in shrub growth and density, but the extent to which shrub growth is expressed in greater shrub ring width and the degree to which natural and experimental warming correspond and or whether the secondary effect of deeper snow in winter acts to alter shrub ring growh and or shrub biomass is yet to be determined for Arctic Alaska. In order to explore growth response of arctic shrubs to on-going and predicted temperature and snow depth increase we investigated shrubs' annual growth rings using dendrochronological methods applied to plants growing under control and experimental treatments in Toolik Lake, Northern Alaska. Specifically we evaluated the effects of a 20-year experimental warming (due to open top chambers, OTC's) and snow depth increases on the growth rings pattern of two common shrub species of Northern Alaska, i.e. Betula nana and Salix pulchra. By applying a serial sectioning method patterns of annual growth were investigated across the entire plant including below-ground parts. Moreover this procedure allowed for a complete cross-dating and a detection of irregular radial growth, including common missing and partially missing rings. We found that the natural warming in Alaska occurring over the past 20 years is stimulating shrub ring growth, more so for Betula than for Salix. Experimental warming (simulating conditions in approximately 2030) stimulated the secondary growth ratio; however the allocation pattern between below-ground and above-ground is quite variable between individual shrubs. In addition, annual growth rings analyses were supplemented by quantitative wood anatomy properties, such as vessel size and density. Our findings indicate that there can be differential growth ring responses of deciduous shrubs to natural climate warming, that growth ring increases reflect

  19. Urinary iodine excretion in relation to goiter prevalence in households of goiter endemic and non endemic regions of Ethiopia

    International Nuclear Information System (INIS)

    Abuye, Chernet; Hailemariam, Bantiyrgu; Neka Tibeb, Hanna; Urga, Kelbesa; Woldegebriel, Zewidie

    1995-01-01

    A Survey of goiter prevalence, among population of five endemic and four non endemic regions of Ethiopia was carried out prior to the distribution of iodate d salt. urine samples were collected from 327 subjects selected by systematic random sampling from endemic and 276 taken as non endemic. The lowest mean urinary iodine excretion (UIE) value was recorded in Bure (22 micro gl/day) and the highest in Alemmaya (148 micro gl/day). The highest goiter rate ( percent TGR) was recorded in Sawla 55.6 %) and the lowest (0.6 %) in Yabello. Iodine content of drinking was in the range of 0.4 - 48.5 micro gl. Iodine content of water source was correlated positively ( r0.8399) with the mean of UIE and TGR, however, indicates that sites considered as non endemic seem to be affected by iodine deficiency. The study results urge the need for intervention in controlling Iodine Deficiency Disorders. 3 tab

  20. Dendrochronological study of the endangered shrub Vella pseudocytisus subsp. paui (Brassicaceae: implications for its recovery and conservation

    Directory of Open Access Journals (Sweden)

    Génova, Mar

    2013-12-01

    Full Text Available Dendrochronology is useful to determine plant longevity, to provide insights into the structure and dynamics of plant populations and to study the relationships between growth and environmental determinants. The dendrochronology of endangered shrubs is unexplored, although their use represents an opportunity to produce better conservation guidelines. We collected for this study 63 samples from already dead specimens of Vella pseudocytisus subsp. paui (Brassicaceae, an endangered Spanish endemism from three localities. We analyzed the relationship between ring data and plant size to determine the accuracy of using size as a proxy for plant age. We also explored the relationships between ring data and environmental variables to detect growth determinants. This shrub showed a high longevity as older individuals presented nearly 50 growth rings. The relationship between age and size is weak although it could be established based on the logarithmic function of plant biovolume. Significant relationships were found between rainfall and ring widths, showing that water limited annual growth. Finally, age structure characterized differences among populations, highlighting the effects of disturbance and land use. These results provided new opportunities for management within the ongoing recovery plan for the species.La dendrocronología es útil para determinar la longevidad de la planta, proporcionar información sobre la estructura y dinámica de las poblaciones vegetales y estudiar las relaciones entre el crecimiento y las variables ambientales. Hasta ahora no se había hecho uso de la dendrocronología en arbustos en peligro de extinción, aunque su empleo puede mejorar las directrices de conservación. En este estudio se han recolectado 63 especímenes ya muertos de tres localidades de Vella pseudocytisus subsp. paui (Brassicaceae, un endemismo español en peligro de extinción. Se han analizado las relaciones entre los grosores del anillo de

  1. Isolation and Characterization of Microsatellite Loci for Hibiscus aridicola (Malvaceae), an Endangered Plant Endemic to the Dry-Hot Valleys of Jinsha River in Southwest China

    Science.gov (United States)

    Zhang, Le; Sun, Weibang; Wang, Zhonglang; Guan, Kaiyun; Yang, Junbo

    2011-01-01

    Hibiscus aridicola (Malvaceae) is an endangered ornamental shrub endemic to the dry-hot valleys of Jinsha River in southwest China. Only four natural populations of H. aridicola exist in the wild according to our field investigation. It can be inferred that H. aridicola is facing a very high risk of extinction in the wild and an urgent conservation strategy is required. By using a modified biotin-streptavidin capture method, a total of 40 microsatellite markers were developed and characterized in H. aridicola for the first time. Polymorphisms were evaluated in 39 individuals from four natural populations. Fifteen of the markers showed polymorphisms with two to six alleles per locus; the observed heterozygosity ranged from 0.19 to 0.72. These microsatellite loci would be useful tools for population genetics studies on H. aridicola and other con-generic species which are important to the conservation and development of endangered species. PMID:22016620

  2. Isolation and Characterization of Microsatellite Loci for Hibiscus aridicola (Malvaceae, an Endangered Plant Endemic to the Dry-Hot Valleys of Jinsha River in Southwest China

    Directory of Open Access Journals (Sweden)

    Kaiyun Guan

    2011-09-01

    Full Text Available Hibiscus aridicola (Malvaceae is an endangered ornamental shrub endemic to the dry-hot valleys of Jinsha River in southwest China. Only four natural populations of H. aridicola exist in the wild according to our field investigation. It can be inferred that H. aridicola is facing a very high risk of extinction in the wild and an urgent conservation strategy is required. By using a modified biotin-streptavidin capture method, a total of 40 microsatellite markers were developed and characterized in H. aridicola for the first time. Polymorphisms were evaluated in 39 individuals from four natural populations. Fifteen of the markers showed polymorphisms with two to six alleles per locus; the observed heterozygosity ranged from 0.19 to 0.72. These microsatellite loci would be useful tools for population genetics studies on H. aridicola and other con-generic species which are important to the conservation and development of endangered species.

  3. Impacts of the removal of shrubs on the physiological and biochemical characteristics of Syntrichia caninervis Mitt: in a temperate desert.

    Science.gov (United States)

    Yin, Ben-Feng; Zhang, Yuan-Ming; Lou, An-Ru

    2017-04-04

    Moss crusts play important roles in biological soil crusts biomass and soil surface stabilization. However, because of increasingly intensive human activities, especially grazing, the growth and survival of shrubs are seriously threatened. This study aimed to test whether the presence of shrubs affects the physiological state of the bryophyte Syntrichia caninervis Mitt. in this desert ecosystem. We simulated animal-grazed shrubs at three levels in the Gurbantunggut Desert and compared these simulations to exposed areas, measuring the indicators of growth and stress tolerance exhibited by bryophytes. The results showed that the removal of shrubs significantly decreased chlorophyll fluorescence activity and soluble protein content in S. caninervis, especially under the total shrub removal treatment. The ratio between the total removal of shrubs and other treatments in antioxidative enzymes and in osmotic adjustment substances of S. caninervis exhibited two types of responses. With the exception of malonyldialdehyde (MDA) and superoxide dismutase (SOD), the variables examined fitted as downward parabolic then upward parabolic temporal dynamics. The removal of shrubs is harmful to the survival of S.caninervis. In resource-constrained conditions, SOD is an important antioxidant enzyme that of peroxidase (POD), catalase (CAT) and osmotic adjustment substances, for S. caninervis survival.

  4. Arizona Libraries: Books to Bytes. Contributed Papers Presented at the AzLA Annual Conference (Phoenix, Arizona, November 17-18, 1995).

    Science.gov (United States)

    Hammond, Carol, Ed.

    This document contains three papers presented at the 1995 Arizona Library Association conference. Papers include: (1) "ERLs and URLs: ASU Libraries Database Delivery Through Web Technology" (Dennis Brunning & Philip Konomos), which illustrates how and why the libraries at Arizona State University developed a world wide web server and…

  5. Rapid carbon turnover beneath shrub and tree vegetation is associated with low soil carbon stocks at a subarctic treeline.

    Science.gov (United States)

    Parker, Thomas C; Subke, Jens-Arne; Wookey, Philip A

    2015-05-01

    Climate warming at high northern latitudes has caused substantial increases in plant productivity of tundra vegetation and an expansion of the range of deciduous shrub species. However significant the increase in carbon (C) contained within above-ground shrub biomass, it is modest in comparison with the amount of C stored in the soil in tundra ecosystems. Here, we use a 'space-for-time' approach to test the hypothesis that a shift from lower-productivity tundra heath to higher-productivity deciduous shrub vegetation in the sub-Arctic may lead to a loss of soil C that out-weighs the increase in above-ground shrub biomass. We further hypothesize that a shift from ericoid to ectomycorrhizal systems coincident with this vegetation change provides a mechanism for the loss of soil C. We sampled soil C stocks, soil surface CO2 flux rates and fungal growth rates along replicated natural transitions from birch forest (Betula pubescens), through deciduous shrub tundra (Betula nana) to tundra heaths (Empetrum nigrum) near Abisko, Swedish Lapland. We demonstrate that organic horizon soil organic C (SOCorg ) is significantly lower at shrub (2.98 ± 0.48 kg m(-2) ) and forest (2.04 ± 0.25 kg m(-2) ) plots than at heath plots (7.03 ± 0.79 kg m(-2) ). Shrub vegetation had the highest respiration rates, suggesting that despite higher rates of C assimilation, C turnover was also very high and less C is sequestered in the ecosystem. Growth rates of fungal hyphae increased across the transition from heath to shrub, suggesting that the action of ectomycorrhizal symbionts in the scavenging of organically bound nutrients is an important pathway by which soil C is made available to microbial degradation. The expansion of deciduous shrubs onto potentially vulnerable arctic soils with large stores of C could therefore represent a significant positive feedback to the climate system. © 2014 John Wiley & Sons Ltd.

  6. Detecting the differences in responses of stomatal conductance to moisture stresses between deciduous shrubs and Artemisia subshrubs.

    Science.gov (United States)

    Gao, Qiong; Yu, Mei; Zhou, Chan

    2013-01-01

    Shrubs and subshrubs can tolerate wider ranges of moisture stresses in both soil and air than other plant life forms, and thus represent greater nonlinearity and uncertainty in ecosystem physiology. The objectives of this paper are to model shrub/subshrub stomatal conductance by synthesizing the field leaf gas exchanges data of 24 species in China, in order to detect the differences between deciduous shrubs and Artemisia subshrubs in their responses of stomatal conductance to changes in the moisture stresses. We revised a model of stomatal conductance by incorporating the tradeoff between xylem hydraulic efficiency and cavitation loss risk. We then fit the model at the three hierarchical levels: global (pooling all data as a single group), three functional groups (deciduous non-legume shrubs, deciduous legume shrubs, and subshrubs in Artemisia genus), and individual observations (species × sites). Bayesian inference with Markov Chain Monte Carlo method was applied to obtain the model parameters at the three levels. We found that the model at the level of functional groups is a significant improvement over that at the global level, indicating the significant differences in the stomatal behavior among the three functional groups. The differences in tolerance and sensitivities to changes in moisture stresses are the most evident between the shrubs and the subshrubs: The two shrub groups can tolerate much higher soil water stress than the subshrubs. The analysis at the observation level is also a significant improvement over that at the functional group level, indicating great variations within each group. Our analysis offered a clue for the equivocal issue of shrub encroachment into grasslands: While the invasion by the shrubs may be irreversible, the dominance of subshrubs, due to their lower resistance and tolerance to moisture stresses, may be put down by appropriate grassland management.

  7. Vegetation ecology and carbon sequestration potential of shrubs in tropics of Chhattisgarh, India.

    Science.gov (United States)

    Jhariya, Manoj Kumar

    2017-09-25

    Tropical forests are well known to have great species diversity and contribute substantial share in terrestrial carbon (C) stocks worldwide. Shrubs are long-neglected life form in the forest ecosystem, playing many roles in the forest and human life. Shrub has great impact on vegetation attributes which in turn modify the C storage and capture. In the present investigation, an attempt has been made to explore the dynamics of shrub species in four fire regimes, viz. high, medium, low, and no fire zones of Bhoramdeo Wildlife Sanctuary of Kawardha forest division (Chhattisgarh), India. The variations in structure, diversity, biomass, productivity, and C sequestration potential in all the sites were quantified. The density and basal area of shrub varied from 1250 to 3750 individuals ha -1 and 2.79 to 4.92 m 2  ha -1 , respectively. The diversity indices showed that the value of Shannon index was highest in medium fire zone (3.77) followed by high, low, and no fire zones as 3.25, 3.12, and 2.32, respectively. The value of Simpson's index or concentration of dominance (Cd) ranged from 0.08 to 0.20, species richness from 0.56 to 1.58, equitability from 1.41 to 1.44, and beta diversity from 1.50 to 4.20, respectively. The total biomass and C storage ranged from 6.82 to 15.71 and from 2.93 to 6.76 t ha -1 , respectively. The shrub density, importance value index (IVI), and abundance to frequency ratio (A/F) significantly correlated between high fire and medium fire zone. The basal area was found to be significantly positively correlated between high fire and medium fire, and low and no fire zones, respectively. Two-way cluster analysis reflected various patterns of clustering due to influence of the forest fire which showed that some species have distant clustering while some have smaller cluster. Principal component analysis (PCA) reflects variable scenario with respect to shrub layer. Ventilago calyculata and Zizyphus rotundifolia showed higher correlation between

  8. Costs of Illness Due to Endemic Cholera

    Science.gov (United States)

    Poulos, C.; Riewpaiboon, A.; Stewart, J.F.; Clemens, J.; Guh, S.; Agtini, M.; Sur, D.; Islam, Z.; Lucas, M.; Whittington, D.

    2013-01-01

    Summary Economic analyses of cholera immunization programmes require estimates of the costs of cholera. The Diseases of the Most Impoverished programme measured the public, provider, and patient costs of culture-confirmed cholera in four study sites with endemic cholera using a combination of hospital- and community-based studies. Families with culture-proven cases were surveyed at home 7 and 14 days after confirmation of illness. Public costs were measured at local health facilities using a micro-costing methodology. Hospital-based studies found that the costs of severe cholera were USD 32 and 47 in Matlab and Beira. Community-based studies in North Jakarta and Kolkata found that cholera cases cost between USD 28 and USD 206, depending on hospitalization. Patient costs of illness as a percentage of average monthly income were 21% and 65% for hospitalized cases in Kolkata and North Jakarta, respectively. This burden on families is not captured by studies that adopt a provider perspective. PMID:21554781

  9. Endemic pemphigus over a century: Part II.

    Science.gov (United States)

    Abréu-Vélez, Ana María; Roselino, Ana Maria; Howard, Michael S; Reason, Iara J de Messias

    2010-03-01

    Endemic pemphigus foliaceus (EPF) is an autoimmune disease, classically occurring in a restricted geographic area. Foci of EPF have been described in several Central and South American countries, often affecting young people and Amerindians, with some female predilection. Although most American EPF cases have been documented in Brazil, cases have been reported in Peru, Paraguay, El Salvador and Venezuela. An additional variant of EPF has been described in El Bagre, Colombia, (El Bagre-EPF) affecting older men and a few post-menopausal females. Finally, one additional type of EPF has been described in nomadic tribes affecting females of child bearing age in Tunisia, Africa. The main aim of this review is to summarize current knowledge about autoantigens, and immunologic and genetic studies in EPF. We utilized a retrospective review of the literature, aiming to compile and compare the multiple geographic foci of EPF. The primary autoantigens in EPF are still considered to be desmogleins in the case of the Tunisian and all American cases, in contradistinction to plakins and desmogleins in El Bagre-EPF. Although several autoantigens are been suggested, their biochemical nature needs further elucidation. Current knowledge still supports the concept that an antibody mediated immune response represents the principal pathophysiology in all variants of EPF. A strong genetic susceptibility appears to contribute to disease development in several people affected by these diseases; however, no specific genes have been confirmed at present. We conclude that further investigation is necessary to define these disorders immunologically and genetically.

  10. Updated Global Burden of Cholera in Endemic Countries

    Science.gov (United States)

    Ali, Mohammad; Nelson, Allyson R.; Lopez, Anna Lena; Sack, David A.

    2015-01-01

    Background The global burden of cholera is largely unknown because the majority of cases are not reported. The low reporting can be attributed to limited capacity of epidemiological surveillance and laboratories, as well as social, political, and economic disincentives for reporting. We previously estimated 2.8 million cases and 91,000 deaths annually due to cholera in 51 endemic countries. A major limitation in our previous estimate was that the endemic and non-endemic countries were defined based on the countries’ reported cholera cases. We overcame the limitation with the use of a spatial modelling technique in defining endemic countries, and accordingly updated the estimates of the global burden of cholera. Methods/Principal Findings Countries were classified as cholera endemic, cholera non-endemic, or cholera-free based on whether a spatial regression model predicted an incidence rate over a certain threshold in at least three of five years (2008-2012). The at-risk populations were calculated for each country based on the percent of the country without sustainable access to improved sanitation facilities. Incidence rates from population-based published studies were used to calculate the estimated annual number of cases in endemic countries. The number of annual cholera deaths was calculated using inverse variance-weighted average case-fatality rate (CFRs) from literature-based CFR estimates. We found that approximately 1.3 billion people are at risk for cholera in endemic countries. An estimated 2.86 million cholera cases (uncertainty range: 1.3m-4.0m) occur annually in endemic countries. Among these cases, there are an estimated 95,000 deaths (uncertainty range: 21,000-143,000). Conclusion/Significance The global burden of cholera remains high. Sub-Saharan Africa accounts for the majority of this burden. Our findings can inform programmatic decision-making for cholera control. PMID:26043000

  11. Feeding and defecation behavior of Triatoma rubida (Uhler, 1894) (Hemiptera: Reduviidae) under laboratory conditions, and its potential role as a vector of Chagas disease in Arizona, USA.

    Science.gov (United States)

    Reisenman, Carolina E; Gregory, Teresa; Guerenstein, Pablo G; Hildebrand, John G

    2011-10-01

    Chagas disease is caused by the parasite Trypanosoma cruzi, which is transmitted to humans by blood-sucking triatomine insects. This disease is endemic throughout Mexico and Central and South America, but only a few autochthonous cases have been reported in the United States, despite the fact that infected insects readily invade houses and feed on humans. Competent vectors defecate during or shortly after feeding so that infective feces contact the host. We thus studied the feeding and defecation behaviors of the prevalent species in southern Arizona, Triatoma rubida. We found that whereas defecation during feeding was frequent in females (93%), it was very rare in immature stages (3%), and absent in males. Furthermore, more than half of the immature insects that exhibited multiple feeding bouts (62%) defecated during interruptions of feeding, i.e., while likely on or near the host. These results indicate that T. rubida potentially could transmit T. cruzi to humans.

  12. [Safety threshold of fluorine in endemic fluorosis regions in China].

    Science.gov (United States)

    Li, Yonghua; Wang, Wuyi; Hou, Shaofan

    2002-07-01

    Four endemic fluorosis regions in China and their environmental epidemiological characteristics were summarized in this paper. It shows that the epidemiology of endemic fluorosis is closely related to geochemical parameters of local environment. The food-web and dose-effect relationship of fluoride from environment to human body in different types of endemic fluorosis regions were studied. And the safety threshold of fluoride in different regions was determined. The results have provided a scientific basis for environmental risk assessment of fluoride in China.

  13. Review: The distribution, flow, and quality of Grand Canyon Springs, Arizona (USA)

    Science.gov (United States)

    Tobin, Benjamin W.; Springer, Abraham E.; Kreamer, David K.; Schenk, Edward

    2018-05-01

    An understanding of the hydrogeology of Grand Canyon National Park (GRCA) in northern Arizona, USA, is critical for future resource protection. The 750 springs in GRCA provide both perennial and seasonal flow to numerous desert streams, drinking water to wildlife and visitors in an otherwise arid environment, and habitat for rare, endemic and threatened species. Spring behavior and flow patterns represent local and regional patterns in aquifer recharge, reflect the geologic structure and stratigraphy, and are indicators of the overall biotic health of the canyon. These springs, however, are subject to pressures from water supply development, changes in recharge from forest fires and other land management activities, and potential contamination. Roaring Springs is the sole water supply for residents and visitors (>6 million/year), and all springs support valuable riparian habitats with very high species diversity. Most springs flow from the karstic Redwall-Muav aquifer and show seasonal patterns in flow and water chemistry indicative of variable aquifer porosities, including conduit flow. They have Ca/Mg-HCO3 dominated chemistry and trace elements consistent with nearby deep wells drilled into the Redwall-Muav aquifer. Tracer techniques and water-age dating indicate a wide range of residence times for many springs, supporting the concept of multiple porosities. A perched aquifer produces small springs which issue from the contacts between sandstone and shale units, with variable groundwater residence times. Stable isotope data suggest both an elevational and seasonal difference in recharge between North and South Rim springs. This review highlights the complex nature of the groundwater system.

  14. Binational Dengue Outbreak Along the United States-Mexico Border - Yuma County, Arizona, and Sonora, Mexico, 2014.

    Science.gov (United States)

    Jones, Jefferson M; Lopez, Benito; Adams, Laura; Gálvez, Francisco Javier Navarro; Núñez, Alfredo Sánchez; Santillán, Nubia Astrid Hernández; Plante, Lydia; Hemme, Ryan R; Casal, Mariana; Hunsperger, Elizabeth A; Muñoz-Jordan, Jorge; Acevedo, Veronica; Ernst, Kacey; Hayden, Mary; Waterman, Steve; Gomez, Diana; Sharp, Tyler M; Komatsu, Kenneth K

    2016-05-20

    Dengue is an acute febrile illness caused by any of four dengue virus types (DENV-1-4). DENVs are transmitted by mosquitos of the genus Aedes (1) and are endemic throughout the tropics (2). In 2010, an estimated 390 million DENV infections occurred worldwide (2). During 2007-2013, a total of three to 10 dengue cases were reported annually in Arizona and all were travel-associated. During September-December 2014, coincident with a dengue outbreak in Sonora, Mexico, 93 travel-associated dengue cases were reported in Arizona residents; 70 (75%) cases were among residents of Yuma County, which borders San Luis Río Colorado, Sonora, Mexico. San Luis Río Colorado reported its first case of locally acquired dengue in September 2014. To investigate the temporal relationship of the dengue outbreaks in Yuma County and San Luis Río Colorado and compare patient characteristics and signs and symptoms, passive surveillance data from both locations were analyzed. In addition, household-based cluster investigations were conducted near the residences of reported dengue cases in Yuma County to identify unreported cases and assess risk for local transmission. Surveillance data identified 52 locally acquired cases (21% hospitalized) in San Luis Río Colorado and 70 travel-associated cases (66% hospitalized) in Yuma County with illness onset during September-December 2014. Among 194 persons who participated in the cluster investigations in Yuma County, 152 (78%) traveled to Mexico at least monthly during the preceding 3 months. Four (2%) of 161 Yuma County residents who provided serum samples for diagnostic testing during cluster investigations had detectable DENV immunoglobulin M (IgM); one reported a recent febrile illness, and all four had traveled to Mexico during the preceding 3 months. Entomologic assessments among 105 households revealed 24 water containers per 100 houses colonized by Ae. aegypti. Frequent travel to Mexico and Ae. aegypti colonization indicate risk for local

  15. Co-occurring nonnative woody shrubs have additive and non-additive soil legacies.

    Science.gov (United States)

    Kuebbing, Sara E; Patterson, Courtney M; Classen, Aimée T; Simberloff, Daniel

    2016-09-01

    To maximize limited conservation funds and prioritize management projects that are likely to succeed, accurate assessment of invasive nonnative species impacts is essential. A common challenge to prioritization is a limited knowledge of the difference between the impacts of a single nonnative species compared to the impacts of nonnative species when they co-occur, and in particular predicting when impacts of co-occurring nonnative species will be non-additive. Understanding non-additivity is important for management decisions because the management of only one co-occurring invader will not necessarily lead to a predictable reduction in the impact or growth of the other nonnative plant. Nonnative plants are frequently associated with changes in soil biotic and abiotic characteristics, which lead to plant-soil interactions that influence the performance of other species grown in those soils. Whether co-occurring nonnative plants alter soil properties additively or non-additively relative to their effects on soils when they grow in monoculture is rarely addressed. We use a greenhouse plant-soil feedback experiment to test for non-additive soil impacts of two common invasive nonnative woody shrubs, Lonicera maackii and Ligustrum sinense, in deciduous forests of the southeastern United States. We measured the performance of each nonnative shrub, a native herbaceous community, and a nonnative woody vine in soils conditioned by each shrub singly or together in polyculture. Soils conditioned by both nonnative shrubs had non-additive impacts on native and nonnative performance. Root mass of the native herbaceous community was 1.5 times lower and the root mass of the nonnative L. sinense was 1.8 times higher in soils conditioned by both L. maackii and L. sinense than expected based upon growth in soils conditioned by either shrub singly. This result indicates that when these two nonnative shrubs co-occur, their influence on soils disproportionally favors persistence

  16. Dark Sky Collaborators: Arizona (AZ) Observatories, Communities, and Businesses

    Science.gov (United States)

    Del Castillo, Elizabeth Alvarez; Corbally, Christopher; Falco, Emilio E.; Green, Richard F.; Hall, Jeffrey C.; Williams, G. Grant

    2015-03-01

    With outdoor lighting ordinances in Arizona first in place around observatories in 1958 and 1972, then throughout the state since 1986, Arizonans have extensive experience working with communities and businesses to preserve our dark skies. Though communities are committed to the astronomy sector in our state, astronomers must collaborate with other stakeholders to implement solutions. Ongoing education and public outreach is necessary to enable ordinance updates as technology changes. Despite significant population increases, sky brightness measurements over the last 20 years show that ordinance updates are worth our efforts as we seek to maintain high quality skies around our observatories. Collaborations are being forged and actions taken to promote astronomy for the longer term in Arizona.

  17. Student research in criticality safety at the University of Arizona

    International Nuclear Information System (INIS)

    Hetrick, D.L.

    1997-01-01

    A very brief progress report on four University of Arizona student projects is given. Improvements were made in simulations of power pulses in aqueous solutions, including the TWODANT model. TWODANT calculations were performed to investigate the effect of assembly shape on the expansion coefficient of reactivity for solutions. Preliminary calculations were made of critical heights for the Los Alamos SHEBA assembly. Calculations to support French experiments to measure temperature coefficients of dilute plutonium solutions confirmed feasibility

  18. Wintering bald eagle trends in northern Arizona, 1975-2000

    Science.gov (United States)

    Teryl G. Grubb

    2003-01-01

    Between 1975 and 2000, 4,525 sightings of wintering bald eagles (Haliaeetus leucocephalus) were recorded at Mormon Lake in northern Arizona. Numbers of wintering eagles fluctuated little in the 20 years from 1975 through 1994 (5.5 ± 3.0 mean sightings per day). However, during the winters of 1995 through 1997 local record highs of 59 to 118 eagles...

  19. Mesozoic mammals from Arizona: new evidence on Mammalian evolution.

    Science.gov (United States)

    Jenkins, F A; Crompton, A W; Downs, W R

    1983-12-16

    Knowledge of early mammalian evolution has been based on Old World Late Triassic-Early Jurassic faunas. The discovery of mammalian fossils of approximately equivalent age in the Kayenta Formation of northeastern Arizona gives evidence of greater diversity than known previously. A new taxon documents the development of an angular region of the jaw as a neomorphic process, and represents an intermediate stage in the origin of mammalian jaw musculature.

  20. Ice fishing by wintering Bald Eagles in Arizona

    Science.gov (United States)

    Teryl G. Grubb; Roy G. Lopez

    1997-01-01

    Northern Arizona winters vary within and between years with occasional heavy snows (up to 0.6 m) and extreme cold (overnight lows -18 to -29°C) interspersed with dry periods, mild temperatures (daytime highs reaching 10°C), and general loss of snow cover at all but highest elevations. Lakes in the area may freeze and thaw partially or totally several times during a...

  1. Moral Consideration Regarding the Arizona Tax Credit Law

    Directory of Open Access Journals (Sweden)

    Anthony G. Rud

    2000-08-01

    Full Text Available I begin by commenting on the language used, both by the Arizona tax credit law, and by our commentators, and then turn to a discussion of a factor I believe fuels the impetus for sectarian education. I end with a consideration of questions related to the social, cognitive, and moral costs of such privatization, in contrast to a democratic commitment to education.

  2. Molecular adaptation during adaptive radiation in the Hawaiian endemic genus Schiedea.

    Directory of Open Access Journals (Sweden)

    Maxim V Kapralov

    2006-12-01

    Full Text Available "Explosive" adaptive radiations on islands remain one of the most puzzling evolutionary phenomena. The rate of phenotypic and ecological adaptations is extremely fast during such events, suggesting that many genes may be under fairly strong selection. However, no evidence for adaptation at the level of protein coding genes was found, so it has been suggested that selection may work mainly on regulatory elements. Here we report the first evidence that positive selection does operate at the level of protein coding genes during rapid adaptive radiations. We studied molecular adaptation in Hawaiian endemic plant genus Schiedea (Caryophyllaceae, which includes closely related species with a striking range of morphological and ecological forms, varying from rainforest vines to woody shrubs growing in desert-like conditions on cliffs. Given the remarkable difference in photosynthetic performance between Schiedea species from different habitats, we focused on the "photosynthetic" Rubisco enzyme, the efficiency of which is known to be a limiting step in plant photosynthesis.We demonstrate that the chloroplast rbcL gene, encoding the large subunit of Rubisco enzyme, evolved under strong positive selection in Schiedea. Adaptive amino acid changes occurred in functionally important regions of Rubisco that interact with Rubisco activase, a chaperone which promotes and maintains the catalytic activity of Rubisco. Interestingly, positive selection acting on the rbcL might have caused favorable cytotypes to spread across several Schiedea species.We report the first evidence for adaptive changes at the DNA and protein sequence level that may have been associated with the evolution of photosynthetic performance and colonization of new habitats during a recent adaptive radiation in an island plant genus. This illustrates how small changes at the molecular level may change ecological species performance and helps us to understand the molecular bases of extremely

  3. Endemic infrared divergences in QED3 at finite temperature

    International Nuclear Information System (INIS)

    Lo, Pok Man; Swanson, Eric S.

    2011-01-01

    We demonstrate that massless QED in three dimensions contains endemic infrared divergences. It is argued that these divergences do not affect observables; furthermore, it is possible to choose a gauge that renders the theory finite.

  4. Chlamydia trachomatis serovars of endemic trachoma had been ...

    African Journals Online (AJOL)

    Journal of Applied Sciences and Environmental Management ... The serovars that we identified from Japanese infants and pregnant women ... Once Japan was thought to be belong to an endemic area of trachoma as other Asian countries.

  5. The dynamics of endemic malaria in populations of varying size

    International Nuclear Information System (INIS)

    Ngwa, G.A.

    2001-10-01

    A mathematical model for endemic malaria involving variable human and mosquito populations is analysed. A threshold parameter R 0 exists and the disease can persist if and only if R 0 exceeds 1. R 0 is seen to be a generalisation of the basic reproduction ratio associated with the Ross-Macdonald model for malaria transmission. The disease free equilibrium always exist and is globally stable when R 0 is below 1. A perturbation analysis is used to approximate the endemic equilibrium in the important case where the disease related death rate is nonzero. A diffusion approximation is used to approximate the quasi-stationary distribution of the associated stochastic model. Numerical simulations show that when R 0 is distinctly greater than 1, the endemic deterministic equilibrium is globally stable. Furthermore, in quasi-stationarity, the stochastic process undergoes oscillations about a mean population whose size can be approximated by the stable endemic deterministic equilibrium. (author)

  6. Spatial distribution of Madeira Island Laurisilva endemic spiders (Arachnida: Araneae)

    Science.gov (United States)

    2014-01-01

    Abstract Madeira island presents a unique spider diversity with a high number of endemic species, many of which are still poorly known. A recent biodiversity survey on the terrestrial arthropods of the native forest, Laurisilva, provided a large set of standardized samples from various patches throughout the island. Out of the fifty two species recorded, approximately 33.3% are Madeiran endemics, many of which had not been collected since their original description. Two new species to science are reported – Ceratinopsis n. sp. and Theridion n. sp. – and the first records of Poeciloneta variegata (Blackwall, 1841) and Tetragnatha intermedia Kulczynski, 1891 are reported for the first time for Madeira island. Considerations on species richness and abundance from different Laurisilva locations are presented, together with distribution maps for endemic species. These results contribute to a better understanding of spider diversity patterns and endemic species distribution in the native forest of Madeira island. PMID:24855443

  7. An Investigation on the antimicrobial activity of some endemic plant ...

    African Journals Online (AJOL)

    SERVER

    2008-01-04

    Jan 4, 2008 ... Key words: Antimicrobial activity, endemic plants, plant extract. INTRODUCTION ..... The essential oil of A. balsamea was found to be inactive against E. ... Origanum solymicum and Origanum bilgeri from Turkey. Afr. J. Trad.

  8. isoenzyme analysis of five endemic and one widespread kniphofia ...

    African Journals Online (AJOL)

    Preferred Customer

    ISOENZYME ANALYSIS OF FIVE ENDEMIC AND ONE WIDESPREAD ... plants. The over all mean inbreeding coefficient (F) was positive indicating slight deficiency in the number of ...... populations, indicates rather recent speciation.

  9. Tobacco Control in Transition: Public Support and Governmental Disarray in Arizona 1997-2007

    OpenAIRE

    Hendlin M.Sc., Yogi H.; Barnes, Richard L JD; Glantz, Stanton A. Ph.D.

    2008-01-01

    • Tobacco control in Arizona flourished from 1997-2007, thanks to public support at the ballot box and the hard work of Arizonan tobacco control activists. • Arizona's state-run Tobacco Education and Prevention Program (TEPP), created by Proposition 200 in 1994 from 23% of a 40 cent tobacco tax increase, provided a key component in Arizona tobacco control, spending between $15 and $36 million annually. • Tobacco control advocacy between 1997 and 2007 resulted in more than tr...

  10. A world malaria map: Plasmodium falciparum endemicity in 2007.

    Directory of Open Access Journals (Sweden)

    Simon I Hay

    2009-03-01

    Full Text Available Efficient allocation of resources to intervene against malaria requires a detailed understanding of the contemporary spatial distribution of malaria risk. It is exactly 40 y since the last global map of malaria endemicity was published. This paper describes the generation of a new world map of Plasmodium falciparum malaria endemicity for the year 2007.A total of 8,938 P. falciparum parasite rate (PfPR surveys were identified using a variety of exhaustive search strategies. Of these, 7,953 passed strict data fidelity tests for inclusion into a global database of PfPR data, age-standardized to 2-10 y for endemicity mapping. A model-based geostatistical procedure was used to create a continuous surface of malaria endemicity within previously defined stable spatial limits of P. falciparum transmission. These procedures were implemented within a Bayesian statistical framework so that the uncertainty of these predictions could be evaluated robustly. The uncertainty was expressed as the probability of predicting correctly one of three endemicity classes; previously stratified to be an informative guide for malaria control. Population at risk estimates, adjusted for the transmission modifying effects of urbanization in Africa, were then derived with reference to human population surfaces in 2007. Of the 1.38 billion people at risk of stable P. falciparum malaria, 0.69 billion were found in Central and South East Asia (CSE Asia, 0.66 billion in Africa, Yemen, and Saudi Arabia (Africa+, and 0.04 billion in the Americas. All those exposed to stable risk in the Americas were in the lowest endemicity class (PfPR2-10 5 to or = 40% areas. High endemicity was widespread in the Africa+ region, where 0.35 billion people are at this level of risk. Most of the rest live at intermediate risk (0.20 billion, with a smaller number (0.11 billion at low stable risk.High levels of P. falciparum malaria endemicity are common in Africa. Uniformly low endemic levels are

  11. A world malaria map: Plasmodium falciparum endemicity in 2007.

    Science.gov (United States)

    Hay, Simon I; Guerra, Carlos A; Gething, Peter W; Patil, Anand P; Tatem, Andrew J; Noor, Abdisalan M; Kabaria, Caroline W; Manh, Bui H; Elyazar, Iqbal R F; Brooker, Simon; Smith, David L; Moyeed, Rana A; Snow, Robert W

    2009-03-24

    Efficient allocation of resources to intervene against malaria requires a detailed understanding of the contemporary spatial distribution of malaria risk. It is exactly 40 y since the last global map of malaria endemicity was published. This paper describes the generation of a new world map of Plasmodium falciparum malaria endemicity for the year 2007. A total of 8,938 P. falciparum parasite rate (PfPR) surveys were identified using a variety of exhaustive search strategies. Of these, 7,953 passed strict data fidelity tests for inclusion into a global database of PfPR data, age-standardized to 2-10 y for endemicity mapping. A model-based geostatistical procedure was used to create a continuous surface of malaria endemicity within previously defined stable spatial limits of P. falciparum transmission. These procedures were implemented within a Bayesian statistical framework so that the uncertainty of these predictions could be evaluated robustly. The uncertainty was expressed as the probability of predicting correctly one of three endemicity classes; previously stratified to be an informative guide for malaria control. Population at risk estimates, adjusted for the transmission modifying effects of urbanization in Africa, were then derived with reference to human population surfaces in 2007. Of the 1.38 billion people at risk of stable P. falciparum malaria, 0.69 billion were found in Central and South East Asia (CSE Asia), 0.66 billion in Africa, Yemen, and Saudi Arabia (Africa+), and 0.04 billion in the Americas. All those exposed to stable risk in the Americas were in the lowest endemicity class (PfPR2-10 5 to or = 40%) areas. High endemicity was widespread in the Africa+ region, where 0.35 billion people are at this level of risk. Most of the rest live at intermediate risk (0.20 billion), with a smaller number (0.11 billion) at low stable risk. High levels of P. falciparum malaria endemicity are common in Africa. Uniformly low endemic levels are found in the

  12. Endangered, rare and endemic medicinal plants of the Kopetdag

    OpenAIRE

    AKMURADOV ALLAMURAD; SHAIYMOV BABAGULY; HALMEDOV BAZAR; YAKUBOV ATABEG; HALLIYEVA GULYAIYM

    2016-01-01

    The article presents some information of the place of growing of the endangered, rare and endemic medicinal plants of the Kopetdag. A monitoring has been carried out and the bioecological peculiarities, resource characteristics and modern state of the natural population of the most important species have been studied. Some scientifically based ways of protection and introduction into culture have been worked out to preserve the endangered, rare and endemic medicinal plants of the region.

  13. Examining the role of shrub expansion and fire in Arctic plant silica cycling

    Science.gov (United States)

    Carey, J.; Fetcher, N.; Parker, T.; Rocha, A. V.; Tang, J.

    2017-12-01

    All terrestrial plants accumulate silica (SiO2) to some degree, although the amount varies by species type, functional group, and environmental conditions. Silica improves overall plant fitness, providing protection from a variety of biotic and abiotic stressors. Plant silica uptake serves to retain silica in terrestrial landscapes, influencing silica export rates from terrestrial to marine systems. These export rates are important because silica is often the limiting nutrient for primary production by phytoplankton in coastal waters. Understanding how terrestrial plant processes influence silica export rates to oceanic systems is of interest on the global scale, but nowhere is this issue more important than in the Arctic, where marine diatoms rely on silica for production in large numbers and terrestrial runoff largely influences marine biogeochemistry. Moreover, the rapid rate of change occurring in the Arctic makes understanding plant silica dynamics timely, although knowledge of plant silica cycling in the region is in its infancy. This work specifically examines how shrub expansion, permafrost thaw, and fire regimes influence plant silica behavior in the Alaskan Arctic. We quantified silica accumulation in above and belowground portions of three main tundra types found in the Arctic (wet sedge, moist acidic, moist non-acidic tundra) and scaled these values to estimate how shrub expansion alters plant silica accumulation rates. Results indicate that shrub expansion via warming will increase silica storage in Arctic land plants due to the higher biomass associated with shrub tundra, whereas conversion of tussock to wet sedge tundra via permafrost thaw would produce the opposite effect in the terrestrial plant BSi pool. We also examined silica behavior in plants exposed to fire, finding that post-fire growth results in elevated plant silica uptake. Such changes in the size of the terrestrial vegetation silica reservoir could have direct consequences for the rates

  14. Nutrient foraging strategies are associated with productivity and population growth in forest shrubs

    Science.gov (United States)

    Stone, Bram W. G.; Faillace, Cara A.; Lafond, Jonathan J.; Baumgarten, Joni M.; Mozdzer, Thomas J.; Dighton, John; Meiners, Scott J.; Grabosky, Jason C.; Ehrenfeld, Joan G.

    2017-01-01

    Background and Aims Temperate deciduous forest understoreys are experiencing widespread changes in community composition, concurrent with increases in rates of nitrogen supply. These shifts in plant abundance may be driven by interspecific differences in nutrient foraging (i.e. conservative vs. acquisitive strategies) and, thus, adaptation to contemporary nutrient loading conditions. This study sought to determine if interspecific differences in nutrient foraging could help explain patterns of shrub success and decline in eastern North American forests. Methods Using plants grown in a common garden, fine root traits associated with nutrient foraging were measured for six shrub species. Traits included the mean and skewness of the root diameter distribution, specific root length (SRL), C:N ratio, root tissue density, arbuscular mycorrhizal colonization and foraging precision. Above- and below-ground productivity were also determined for the same plants, and population growth rates were estimated using data from a long-term study of community dynamics. Root traits were compared among species and associations among root traits, measures of productivity and rates of population growth were evaluated. Key Results Species fell into groups having thick or thin root forms, which correspond to conservative vs. acquisitive nutrient foraging strategies. Interspecific variation in root morphology and tissue construction correlated with measures of productivity and rates of cover expansion. Of the four species with acquisitive traits, three were introduced species that have become invasive in recent decades, and the fourth was a weedy native. In contrast, the two species with conservative traits were historically dominant shrubs that have declined in abundance in eastern North American forests. Conclusions In forest understoreys of eastern North America, elevated nutrient availability may impose a filter on species success in addition to above-ground processes such as herbivory

  15. Reproduction and vegetative growth in the dioecious shrub Acer barbinerve in temperate forests of Northeast China.

    Science.gov (United States)

    Wang, Juan; Zhang, Chunyu; Gadow, Klaus V; Cheng, Yanxia; Zhao, Xiuhai

    2015-06-01

    Trade-off in dioecious plant. The trade-off between reproduction, vegetative growth and maintenance is a major issue in the life history of an organism and a record of the process which is producing the largest possible number of living offspring by natural selection. Dioecious species afford an excellent opportunity for detecting such possible trade-offs in resource allocation. In this study, we selected the dioecious shrub Acer barbinerve to examine possible trade-offs between reproduction and vegetative growth in both genders at different modular levels during three successive years. Reproductive and vegetative biomass values were assessed during successive years to evaluate their intra-annual and inter-annual trade-offs. These trade-offs were examined at shoot, branch and shrub modular levels in Acer barbinerve shrubs. An intra-annual trade-off was detected at the shoot level for both genders in 2011 and 2012. Both males and females showed a negative correlation between reproduction and vegetative growth, but this was more prominent in males. For the females of the species, inter-annual trade-offs were only found at branch and shrub levels. Slightly negative correlations in females were detected between the reproduction in 2012 and the reproduction in the two previous years. The gender ratio was significantly male biased during the three successive years of our investigation. Females had higher mortality rates in the larger diameter classes, both in 2011 and 2012. This study revealed a clear trade-off between reproduction and vegetative growth in Acer barbinerve, but results varied between males and females. The degree of autonomy of the different modular levels may affect the ability to detect such trade-offs.

  16. Seasonal Dynamics of Water Use Strategy of Two Salix Shrubs in Alpine Sandy Land, Tibetan Plateau.

    Science.gov (United States)

    Zhu, Yajuan; Wang, Guojie; Li, Renqiang

    2016-01-01

    Water is a limiting factor for plant growth and vegetation dynamics in alpine sandy land of the Tibetan Plateau, especially with the increasing frequency of extreme precipitation events and drought caused by climate change. Therefore, a relatively stable water source from either deeper soil profiles or ground water is necessary for plant growth. Understanding the water use strategy of dominant species in the alpine sandy land ecosystem is important for vegetative rehabilitation and ecological restoration. The stable isotope methodology of δD, δ18O, and δ13C was used to determine main water source and long-term water use efficiency of Salix psammophila and S. cheilophila, two dominant shrubs on interdune of alpine sandy land in northeastern Tibetan Plateau. The root systems of two Salix shrubs were investigated to determine their distribution pattern. The results showed that S. psammophila and S. cheilophila absorbed soil water at different soil depths or ground water in different seasons, depending on water availability and water use strategy. Salix psammophila used ground water during the growing season and relied on shallow soil water recharged by rain in summer. Salix cheilophila used ground water in spring and summer, but relied on shallow soil water recharged by rain in spring and deep soil water recharged by ground water in fall. The two shrubs had dimorphic root systems, which is coincident with their water use strategy. Higher biomass of fine roots in S. psammophila and longer fine roots in S. cheilophila facilitated to absorb water in deeper soil layers. The long-term water use efficiency of two Salix shrubs increased during the dry season in spring. The long-term water use efficiency was higher in S. psammophila than in S. cheilophila, as the former species is better adapted to semiarid climate of alpine sandy land.

  17. Tolerance of an expanding subarctic shrub, Betula glandulosa, to simulated caribou browsing.

    Directory of Open Access Journals (Sweden)

    Emilie Champagne

    Full Text Available Densification of the shrub layer has been reported in many subarctic regions, raising questions about the implication for large herbivores and their resources. Shrubs can tolerate browsing and their level of tolerance could be affected by browsing and soils productivity, eventually modifying resource availability for the caribou. Our objective was to assess the compensatory growth potential of a subarctic shrub, Betula glandulosa Michx., in relation with caribou browsing and nutriment availability for the plants. We used a simulated browsing (0, 25 and 75% of available shoots and nitrogen-fertilisation (0 and 10 g m(-2 experiment to test two main hypotheses linking tolerance to resource availability, the Compensatory Continuum Hypothesis and the Growth Rate Hypothesis as well as the predictions from the Limiting Resource Model. We seek to explicitly integrate the relative browsing pressure in our predictions since the amount of tissues removed could affect the capacity of long-lived plants to compensate. Birches fully compensated for moderate browsing with an overall leaf biomass similar to unbrowsed birches but undercompensated under heavy browsing pressure. The main mechanism explaining compensation appears to be the conversion of short shoots into long shoots. The leaf area increased under heavy browsing pressure but only led to undercompensation. Fertilisation for two consecutive years did not influence the response of birch, thus we conclude that our results support the LRM hypothesis of equal tolerance under both high and low nitrogen availability. Our results highlight that the potential for compensatory growth in dwarf birch is surpassed under heavy browsing pressure independently of the fertilisation regime. In the context of the worldwide decline in caribou herds, the reduction in browsing pressure could act synergistically with global climate change to promote the current shrub expansion reported in subarctic regions.

  18. Spatial patterns and natural recruitment of native shrubs in a semi-arid sandy land.

    Science.gov (United States)

    Wu, Bo; Yang, Hongxiao

    2013-01-01

    Passive restoration depending on native shrubs is an attractive approach for restoring desertified landscapes in semi-arid sandy regions. We sought to understand the relationships between spatial patterns of native shrubs and their survival ability in sandy environments. Furthermore, we applied our results to better understand whether passive restoration is feasible for desertified landscapes in semi-arid sandy regions. The study was conducted in the semi-arid Mu Us sandy land of northern China with the native shrub Artemisia ordosica. We analyzed population structures and patterns of A. ordosica at the edges and centers of land patches where sand was stabilized by A. ordosica-dominated vegetation. Saplings were more aggregated than adults, and both were more aggregated at the patch edges than at the patch centers. At the patch edges, spatial association of the saplings with the adults was mostly positive at distances 0.3-6.6 m, and turned from positive to neutral, and even negative, at other distances. At the patch centers, the saplings were spaced almost randomly around the adults, and their distances from the adults did not seem to affect their locations. A greater number of A. ordosica individuals emerged at the patch edges than at the patch centers. Such patterns may have resulted from their integrative adjustment to specific conditions of soil water supply and sand drift intensity. These findings suggest that in semi-arid sandy regions, native shrubs that are well-adapted to local environments may serve as low-cost and competent ecological engineers that can promote the passive restoration of surrounding patches of mobile sandy land.

  19. Endemic harvestmen and spiders of Austria (Arachnida: Opiliones, Araneae

    Directory of Open Access Journals (Sweden)

    Komposch, Christian

    2011-01-01

    Full Text Available A comprehensive overview of plant, fungus and animal species of Austria revealed a total of 748 endemic and subendemic species, including, 11 harvestman and 46 spider species. Altogether two endemic harvestmen (Nemastoma bidentatum relictum, Nemastoma schuelleri and 8 endemic spiders (Abacoproeces molestus, Collinsia (caliginosa nemenziana, Mughiphantes severus, Mughiphantes styriacus, Pelecopsis alpica, Scotophaeus nanus, Troglohyphantes novicordis, Troglohyphantes tauriscus, beside 9 subendemic harvestman and 38 subendemic spider species have been recorded from Austria. Hot-spots of endemism in the Eastern Alps are the north-eastern (Ennstaler Alps and southern Calcareous Alps (Karawanken, Karnische Alps and the Central Alps (Hohe Tauern, Gurktaler Alps, Ötztaler and Stubaier Alps. Most of the endemic arachnid species occur from the nival down to the montane zone. Important habitats are rocky areas, caves and woodlands. High absolute numbers and percentages of endemics can be found within the harvestman families Cladonychiidae, Ischyropsalididae and Nemastomatidae and in the spider genera Lepthyphantes s. l. and Troglohyphantes. The conservation status of these highly endangered taxa – 85 % of the spider species and 100 % of the harvestman taxa are endangered in Austria – is poor.

  20. Shrub type dominates the vertical distribution of leaf C : N : P stoichiometry across an extensive altitudinal gradient

    Directory of Open Access Journals (Sweden)

    W. Zhao

    2018-04-01

    Full Text Available Understanding leaf stoichiometric patterns is crucial for improving predictions of plant responses to environmental changes. Leaf stoichiometry of terrestrial ecosystems has been widely investigated along latitudinal and longitudinal gradients. However, very little is known about the vertical distribution of leaf C : N : P and the relative effects of environmental parameters, especially for shrubs. Here, we analyzed the shrub leaf C, N and P patterns in 125 mountainous sites over an extensive altitudinal gradient (523–4685 m on the Tibetan Plateau. Results showed that the shrub leaf C and C : N were 7.3–47.5 % higher than those of other regional and global flora, whereas the leaf N and N : P were 10.2–75.8 % lower. Leaf C increased with rising altitude and decreasing temperature, supporting the physiological acclimation mechanism that high leaf C (e.g., alpine or evergreen shrub could balance the cell osmotic pressure and resist freezing. The largest leaf N and high leaf P occurred in valley region (altitude 1500 m, likely due to the large nutrient leaching from higher elevations, faster litter decomposition and nutrient resorption ability of deciduous broadleaf shrub. Leaf N : P ratio further indicated increasing N limitation at higher altitudes. Interestingly, drought severity was the only climatic factor positively correlated with leaf N and P, which was more appropriate for evaluating the impact of water status than precipitation. Among the shrub ecosystem and functional types (alpine, subalpine, montane, valley, evergreen, deciduous, broadleaf, and conifer, their leaf element contents and responses to environments were remarkably different. Shrub type was the largest contributor to the total variations in leaf stoichiometry, while climate indirectly affected the leaf C : N : P via its interactive effects on shrub type or soil. Collectively, the large heterogeneity in shrub type was the most

  1. Is the herb-shrub composition of veredas (Brazilian palm swamps distinguishable?

    Directory of Open Access Journals (Sweden)

    Diogo Pereira da Silva

    2017-11-01

    Full Text Available ABSTRACT Vereda (Brazilian palm swamp is a poorly known savannic phytophysiognomy that occurs on moist soils with high herb-shrub floristic richness. This study aimed to document the herb-shrub species of veredas of the Estação Ecológica Serra Geral do Tocantins - EESGTO, and compare this flora with other veredas in Brazil. Furthermore, we assessed the similarity of the herb-shrub flora of the studied veredas with that of inventories of other savannas and grasslands in order to evaluate whether veredas possess an exclusive flora. Ordination analysis was performed to understand the floristic relationship among these areas. We recorded 213 species, 105 genera and 49 families at EESGTO, including five new floral records for the Cerrado and 78 for the state of Tocantins. The floristic similarity among veredas at EESGTO and the other sites was low. For all sites, a total of 1,324 species were recorded, of which 342 were unique to veredas and 187 unique to moist grasslands (campos limpos úmidos. After reviewing databases, 14.3 % of these species remained exclusive to veredas and moist grasslands. The ordination analysis indicated a gradient in floristic composition from wet to dry phytophysiognomies. In conclusion, we recognize a flora that distinguishes veredas from other Cerrado phytophysiognomies.

  2. Weak Evidence of Regeneration Habitat but Strong Evidence of Regeneration Niche for a Leguminous Shrub

    Science.gov (United States)

    Delerue, Florian; Gonzalez, Maya; Michalet, Richard; Pellerin, Sylvain; Augusto, Laurent

    2015-01-01

    The identification of an ecological niche specific to the regeneration phase has mobilised significant attention. However, the importance of the regeneration niche concept remains unclear. Our main objective was to study the existence of such a regeneration niche for a leguminous shrub, Ulex europaeus. This study was carried out in southwest France in the context of water and nutrient stresses (mainly phosphorus limitation) due to the presence of nutrient-poor sandy soils. We analysed the regeneration of the species from the germination of seeds and emergence of new seedlings until the seedlings reached young shrub size. Our design included a P fertilisation treatment. We also investigated microsite characteristics (micro-topography and vegetation development) as they can interact with meteorological conditions and determine water availability for seeds and seedlings. We found that P availability controlled seedling growth and the time necessary to reach young shrub size. Water availability appeared to impact the species germination and seedlings survival. We also found that P and water availability depended on the interactions between microsite characteristics and climatic variations. Finally we found evidence that P and water availability are important ecological factors shaping the regeneration niche of the species, but we found weak evidence that any microsite would be appropriate for the regeneration of the species in the long term. Future studies regarding regeneration niches need to distinguish more clearly the ecological factors important for regeneration (the regeneration niche per se) and the physical world where the seedlings appear and develop (the regeneration habitat). PMID:26098877

  3. Weak Evidence of Regeneration Habitat but Strong Evidence of Regeneration Niche for a Leguminous Shrub.

    Directory of Open Access Journals (Sweden)

    Florian Delerue

    Full Text Available The identification of an ecological niche specific to the regeneration phase has mobilised significant attention. However, the importance of the regeneration niche concept remains unclear. Our main objective was to study the existence of such a regeneration niche for a leguminous shrub, Ulex europaeus. This study was carried out in southwest France in the context of water and nutrient stresses (mainly phosphorus limitation due to the presence of nutrient-poor sandy soils. We analysed the regeneration of the species from the germination of seeds and emergence of new seedlings until the seedlings reached young shrub size. Our design included a P fertilisation treatment. We also investigated microsite characteristics (micro-topography and vegetation development as they can interact with meteorological conditions and determine water availability for seeds and seedlings. We found that P availability controlled seedling growth and the time necessary to reach young shrub size. Water availability appeared to impact the species germination and seedlings survival. We also found that P and water availability depended on the interactions between microsite characteristics and climatic variations. Finally we found evidence that P and water availability are important ecological factors shaping the regeneration niche of the species, but we found weak evidence that any microsite would be appropriate for the regeneration of the species in the long term. Future studies regarding regeneration niches need to distinguish more clearly the ecological factors important for regeneration (the regeneration niche per se and the physical world where the seedlings appear and develop (the regeneration habitat.

  4. Convergent production and tolerance among 107 woody species and divergent production between shrubs and trees.

    Science.gov (United States)

    He, Wei-Ming; Sun, Zhen-Kai

    2016-02-08

    Green leaves face two fundamental challenges (i.e., carbon fixation and stress tolerance) during their lifespan. However, the relationships between leaf production potential and leaf tolerance potential have not been explicitly tested with a broad range of plant species in the same environment. To do so, we conducted a field investigation based on 107 woody plants grown in a common garden and complementary laboratory measurements. The values, as measured by a chlorophyll meter, were significantly related to the direct measurements of chlorophyll content on a leaf area basis. Area-based chlorophyll content was positively correlated with root surface area, whole-plant biomass, leaf mass per area (LMA), and force to punch. Additionally, LMA had a positive correlation with force to punch. Shrubs had a higher leaf chlorophyll content than trees; however, shrubs and trees exhibited a similar leaf lifespan, force to punch, and LMA. These findings suggest that the production potential of leaves and their tolerance to stresses may be convergent in woody species and that the leaf production potential may differ between shrubs and trees. This study highlights the possibility that functional convergence and divergence might be linked to long-term selection pressures and genetic constraints.

  5. Growth and defense in deciduous trees and shrubs under UV-B

    International Nuclear Information System (INIS)

    Julkunen-Tiitto, Riitta; Haeggman, Hely; Aphalo, Pedro J.; Lavola, Anu; Tegelberg, Riitta; Veteli, Timo

    2005-01-01

    Reflection by waxy or resinous surface structures and hairs, repair reactions of biomolecules and induction of different sheltering components provide the means of plant protection from harmful solar UV-B radiation. Secondary products, especially flavonoids and phenolic acids as defense components are also important in plant tolerance to UV-B, fulfilling the dual role as screens that reduce UV-B penetration in plant tissues, and as antioxidants protecting from damage by reactive oxidant species. Plants are sensitive to UV-B radiation, and this sensitivity can be even more clone-specific than species-specific. The results available in the literature for deciduous trees and shrubs indicate that UV-B radiation may affect several directions in the interaction of woody species with biotic (herbivores) and abiotic (CO 2 and nutrition) factors depending on the specific interaction in question. These multilevel interactions should have moderate ecological significance via the overall changed performance of woody species and shrubs. - The growth performance of deciduous trees and shrubs under UV-B irradiation is constrained by multilevel interactions with many abiotic and biotic factors

  6. [Ability of typical greenery shrubs of Beijing to adsorb and arrest PM2.5 ].

    Science.gov (United States)

    Liang, Dan; Wang, Bin; Wang, Yun-qi; Zhang, Hui-lan; Yang, Song-nan; Li, Ang

    2014-09-01

    Four typical types of green shrubs of Beijing (Euonymus japonicus, Buxus microphylla, Berberis thunbergii cv. atropurpurea, Taxus cuspidate cv. nana) were selected to study their capacities in adsorbing and arresting PM2.5 using both field observations and air chamber simulations. Concurrently, in order to analyze the pollution characteristics of Beijing in winter and spring, the PM2.5 concentrations of December 2012 to May 2013 were collected. Experimental results showed that: From the gas chamber experiments, the ability to adsorb and arrest PM2.5 was in the order of Berberis thunbergii cv. atropurpurea > Buxus microphylla > Taxus cuspidate cv. nana > Euonymus japonicus, mainly due to the differences in leaf characteristics; Outside measurement results showed that the ability to adsorb and arrest PM2.5 was ranked as Buxus microphylla > Berberis thunbergii cv. atropurpurea > Taxus cuspidate cv. nana > Euonymus japonicus. Chamber simulation and outdoor observation showed that Buxus microphylla and Berberis thunbergii cv. atropurpurea had strong ability to adsorb and arrest PM2.5; Meanwhile, the slight differences between the chamber simulation and outdoor observation results might be related to plant structure. Compared to tree species, the planting condition of shrub species was loose, and it greened quickly; By analyzing the Beijing PM2.5 concentration values in winter and spring, it was found that the PM2.5 concentration was particularly high in the winter of Beijing, and evergreen shrubs maintained the ability to adsorb and arrest PM2.5.

  7. Shrub resprouting response after fuel reduction treatments: comparison of prescribed burning, clearing and mastication.

    Science.gov (United States)

    Fernández, Cristina; Vega, José A; Fonturbel, Teresa

    2013-03-15

    Fuel reduction treatments are commonly used to reduce the risk of severe wildfire. However, more information about the effects on plant resprouting is needed to help land managers select the most appropriate treatment. To address this question, we evaluated the resprouting ability of five shrub species after the application of different types of fuel reduction methods (prescribed burning, clearing and mastication) in two contrasting shrubland areas in northern Spain. The shrub species were Erica australis, Pterospartum tridentatum and Halimium lasianthum spp. alyssoides, Ulex gallii and Erica cinerea. For most of the species under study (E. australis, P. tridentatum, H. lasianthum spp. alyssoides and U. gallii), neither plant mortality nor the number nor length of sprouted shoots per plant differed between treatments, although in E. cinerea the number of shoots was more negatively affected by prescribed burning than by clearing or mastication. The pre-treatment plant size did not affect plant mortality or plant resprouting response, suggesting that this parameter alone is not a good indicator of plant resprouting after fuel reduction treatments. Stem minimum diameter after treatments, a proxy of treatment severity, was not related to plant mortality, number or length of resprouted shoots. The duration of temperatures higher than 300 °C during burning in plant crown had a negative effect on the length of resprouted shoots, only in E. cinerea. The results show that fuel reduction treatments did not prevent shrub response in any case. Some reflections on the applicability of treatments are discussed. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Ecophysiological and anatomical characteristics of the subtropical shrub Zanthoxylum acanthopodium (Rutaceae) in conditions of a temperate continental climate (Serbia)

    DEFF Research Database (Denmark)

    Rakic, Tamara; Sinzar-Sekulic, Jasmina; Filipovic, Biljana

    2009-01-01

    The evergreen shrub Zanthoxylum acanthopodium DC. (Rutaceae), originating from warm temperate and subtropical Asia, has existed successfully in the Jevremovac Botanical Garden in Belgrade for more than 80 years. The seasonal pattern of water management in leaves, electrolyte leakage, essential oil...... composition, and leaf anatomy were examined in order to understand the resistance and viability of this subtropical shrub in the temperate continental climate of Belgrade, Serbia....

  9. The potential for mycobiont sharing between shrubs and seedlings to facilitate tree establishment after wildfire at Alaska arctic treeline.

    Science.gov (United States)

    Hewitt, Rebecca E; Chapin, F Stuart; Hollingsworth, Teresa N; Taylor, D Lee

    2017-07-01

    Root-associated fungi, particularly ectomycorrhizal fungi (EMF), are critical symbionts of all boreal tree species. Although climatically driven increases in wildfire frequency and extent have been hypothesized to increase vegetation transitions from tundra to boreal forest, fire reduces mycorrhizal inoculum. Therefore, changes in mycobiont inoculum may potentially limit tree-seedling establishment beyond current treeline. We investigated whether ectomycorrhizal shrubs that resprout after fire support similar fungal taxa to those that associate with tree seedlings that establish naturally after fire. We then assessed whether mycobiont identity correlates with the biomass or nutrient status of these tree seedlings. The majority of fungal taxa observed on shrub and seedling root systems were EMF, with some dark septate endophytes and ericoid mycorrhizal taxa. Seedlings and adjacent shrubs associated with similar arrays of fungal taxa, and there were strong correlations between the structure of seedling and shrub fungal communities. These results show that resprouting postfire shrubs support fungal taxa compatible with tree seedlings that establish after wildfire. Shrub taxon, distance to the nearest shrub and fire severity influenced the similarity between seedling and shrub fungal communities. Fungal composition was correlated with both foliar C:N ratio and seedling biomass and was one of the strongest explanatory variables predicting seedling biomass. While correlative, these results suggest that mycobionts are important to nutrient acquisition and biomass accrual of naturally establishing tree seedlings at treeline and that mycobiont taxa shared by resprouting postfire vegetation may be a significant source of inoculum for tree-seedling establishment beyond current treeline. © 2017 John Wiley & Sons Ltd.

  10. Ungulate browsing maintains shrub diversity in the absence of episodic disturbance in seasonally-arid conifer forest.

    Directory of Open Access Journals (Sweden)

    Burak K Pekin

    Full Text Available Ungulates exert a strong influence on the composition and diversity of vegetation communities. However, little is known about how ungulate browsing pressure interacts with episodic disturbances such as fire and stand thinning. We assessed shrub responses to variable browsing pressure by cattle and elk in fuels treated (mechanical removal of fuels followed by prescribed burning and non-fuels treated forest sites in northeastern Oregon, US. Seven treatment paddocks were established at each site; three with cattle exclusion and low, moderate and high elk browsing pressure, three with elk exclusion and low, moderate and high cattle browsing pressure, and one with both cattle and elk exclusion. The height, cover and number of stems of each shrub species were recorded at multiple plots within each paddock at the time of establishment and six years later. Changes in shrub species composition over the six year period were explored using multivariate analyses. Generalized Linear Mixed Models were used to determine the effect of browsing pressure on the change in shrub diversity and evenness. Vegetation composition in un-browsed paddocks changed more strongly and in different trajectories than in browsed paddocks at sites that were not fuels treated. In fuels treated sites, changes in composition were minimal for un-browsed paddocks. Shrub diversity and evenness decreased strongly in un-browsed paddocks relative to paddocks with low, moderate and high browsing pressure at non-fuels treated sites, but not at fuels treated sites. These results suggest that in the combined absence of fire, mechanical thinning and ungulate browsing, shrub diversity is reduced due to increased dominance by certain shrub species which are otherwise suppressed by ungulates and/or fuels removal. Accordingly, ungulate browsing, even at low intensities, can be used to suppress dominant shrub species and maintain diversity in the absence of episodic disturbance events.

  11. δ13C values of soil organic matter in semiarid grassland with mesquite (Prosopis) encroachment in southeastern Arizona

    Science.gov (United States)

    Biggs, Thomas H.; Quade, Jay; Webb, Robert H.

    2002-01-01

    Over the past century, C3 woody plants and trees have increased in abundance in many semiarid ecosystems, displacing native C4 grasses. Livestock grazing, climatic fluctuations, and fire suppression are several reasons proposed for this shift. Soil carbon isotopic signatures are an ideal technique to evaluate carbon turnover rates in such ecosystems. On the gunnery ranges of Fort Huachuca in southeastern Arizona, study sites were established on homogeneous granitic alluvium to investigate the effects of fire frequency on δ13C values in surface soil organic matter (SOM). These ranges have had no livestock grazing for 50 years and a well-documented history of fires. Prosopis velutina Woot. (mesquite) trees have altered SOM δ13C pools by the concentration of plant nutrients and the addition of isotopically light litter. These soil carbon changes do not extend beyond canopy margins. Elevated total organic carbon (TOC), plant nutrient (N and P) concentrations, and depleted SOM δ13C values are associated with C3Prosopis on an unburned plot, which enables recognition of former Prosopis-occupied sites on plots with recent fire histories. Elevated nutrient concentrations associated with former Prosopis are retained in SOM for many decades. Surface SOM δ13C values indicate the estimated minimum turnover time of C4-derived carbon beneath large mature Prosopis is about 100–300 years. In contrast, complete turnover of original C3 carbon to C4 carbon under grasslands is estimated to take a minimum of 150–500 years. Our study confirms that C4 grass cover has declined over the past 100 years, although isolated C3 trees or shrubs were not uncommon on the historic C4-dominated grasslands. We find evidence in surface soil layers for a modern C3 plant expansion reflected in the substantial shift of SOM δ13C values from C4 grasses to C3 shrublands.

  12. Shrub growth and expansion in the Arctic tundra: an assessment of controlling factors using an evidence-based approach

    Science.gov (United States)

    Martin, Andrew C.; Jeffers, Elizabeth S.; Petrokofsky, Gillian; Myers-Smith, Isla; Macias-Fauria, Marc

    2017-08-01

    Woody shrubs have increased in biomass and expanded into new areas throughout the Pan-Arctic tundra biome in recent decades, which has been linked to a biome-wide observed increase in productivity. Experimental, observational, and socio-ecological research suggests that air temperature—and to a lesser degree precipitation—trends have been the predominant drivers of this change. However, a progressive decoupling of these drivers from Arctic vegetation productivity has been reported, and since 2010, vegetation productivity has also been declining. We created a protocol to (a) identify the suite of controls that may be operating on shrub growth and expansion, and (b) characterise the evidence base for controls on Arctic shrub growth and expansion. We found evidence for a suite of 23 proximal controls that operate directly on shrub growth and expansion; the evidence base focused predominantly on just four controls (air temperature, soil moisture, herbivory, and snow dynamics). 65% of evidence was generated in the warmest tundra climes, while 24% was from only one of 28 floristic sectors. Temporal limitations beyond 10 years existed for most controls, while the use of space-for-time approaches was high, with 14% of the evidence derived via experimental approaches. The findings suggest the current evidence base is not sufficiently robust or comprehensive at present to answer key questions of Pan-Arctic shrub change. We suggest future directions that could strengthen the evidence, and lead to an understanding of the key mechanisms driving changes in Arctic shrub environments.

  13. Effects of sand burial on the survival and growth of two shrubs dominant in different habitats of northern China.

    Science.gov (United States)

    Qu, Hao; Zhao, Ha-Lin; Zhao, Xue-Yong; Zuo, Xiao-An; Wang, Shao-Kun; Chen, Min

    2017-04-01

    Plants that grow in dune ecosystems always suffer from sand burial. Shrubs play implications on the healthy functioning of dune ecosystems due to control blowing sand. However, the survival and growth responses of shrubs to sand burial remain poorly understood. The survival rate and seedling height of two shrubs (Artemisia halodendron and Lespedeza davurica) along with the soil properties under different burial depths were examined in order to reveal the causing ecophysiological attributes of sand burial on shrubs in the desertified region. It was found that A. halodendron can survive a burial depth of 6 cm greater than its seedling height, which is a dominant shrub in mobile dunes with intense burial, whereas a burial depth equivalent to three fourths of its seedling height is detrimental to L. davurica, which is dominant in fixed dunes with less burial. The reasons for the shrub death under sand burial were associated with the physical barrier to vertical growth and the reduction in photosynthetic area. In conclusion, A. halodendron can facilitate the stabilization of mobile dunes because of their high tolerance to the frequent and intensive sand burial, while L. davurica can be beneficial for the recovery process because of their higher survival rates under shallow burial following restoration of mobile dunes.

  14. Biology of Pink Hibiscus MealybugMaconellicoccushirsutus (Green on Chinese Hibiscus Shrubs in Khuzestan Province

    Directory of Open Access Journals (Sweden)

    M. Sadat Alizadeh

    2017-12-01

    Full Text Available Introduction: The pink hibiscus mealybug, Maconellicoccushirsutus (Green (Hem.:Pseudococcidae is one of the serious economic pests of agricultural crops in tropical and subtropical regions.This pesthas spread through Asia, Africa, America and Australia, and infests more than 330 host plants which some of them have the important role in theeconomy. This sap-feeding insect secrets honeydew which provides suitablemedium for black sooty moldgrowth. It also releases a toxin during feeding, which results in severe stunting, decline, and deformation of twigs. It has recorded as a pest on different host plants in southern Iranian provinces since the 1990s.In Khuzestan province, it was first observed on Chinese hibiscus shrubs in urban landscapes of Ahvaz in February 2009. The evergreen hibiscus shrub is very common in the urban landscape of warmcities of Khuzestan province. The severity of mealybug damage to hibiscus shrubs causedto becut off in some regions. As there is no data on the biology of M. hirsutus in Iran,in the present study, the biologyof this pestwas investigatedat different temperatures in laboratory conditions as well as its population fluctuations on Chinese hibiscus shrubs in urban landscapes of Ahvaz. Materials and methods: Biology of the pest species was evaluated at five laboratory constant temperatures 15, 20, 25, 30and 35±2°C (65±5% RH and a photoperiod of L: D 14:10 h on Chinese hibiscus leaves in plastic boxes (8×6×2 cm. Number ofM. hirsutusgenerations was also studied in clip cages on hibiscus shrubs in Ahvaz urban landscapes within a year. Population fluctuations of the insect were also investigated on those shrubs in two different regions of Ahvaz for 16 months. For this purpose, random sampling was done on five shrubs in each region bi-weekly. Eight twigs, 5 cm in length, were cut from the upper and lower halves of each shrub quadrant and a number of all mealybug developmental stages per twig were counted and recorded

  15. Altered Plant Litter and Microbial Composition Lead to Topsoil Organic Carbon Loss Over a Shrub-encroachment Gradient in an Inner Mongolia Grassland

    Science.gov (United States)

    Zhou, L.; Li, H.; Shen, H.; Xu, Y.; Wang, Y.; Xing, A.; Fang, J.

    2017-12-01

    Over the past 150 years, shrub encroachment has occurred in arid and semi-arid ecosystems resulting from climate change and increased human disturbance. Previous studies have revealed that shrub encroachment has substantial effects on habitat heterogeneity, aboveground biomass and bulk carbon content of grasslands, thereby affecting the regional carbon balance. Soil organic carbon (SOC) is mainly derived from aboveground litter, root litter and root exudates and is metabolized by microorganisms. The quality and quantity of plant litter together with soil microbial biomass are important drivers of SOC accumulation. However, the mechanisms regulating soil carbon accumulation by the shrub encroachment remain unclear and molecular evidence is particularly lacking. We use the data of the chemical composition of plant tissues and SOC, and the soil microbial communities to identify the effects of shrub encroachment on SOC accumulation in the top layer along a gradient of natural shrub cover in the grasslands of Inner Mongolia. Our finding indicates that nitrogen-rich legume-shrub encroachment led to soil carbon accumulation in the shrub patch, with more extensive carbon loss observed in the grassy matrix, which resulted in an overall carbon loss. In the pure grassland, a higher abundance of cutin and suberin and a lower concentration of free lipids were detected, suggesting the preservation of recalcitrant polymers derived from herb inputs. In the shrub-encroached grasslands, the labile shrub leaves did not decompose alone but were mixed with herb litter to promote the degradation of SOC via the priming of microbial activities. The SOC remained unchanged in the shrub patches with the increasing shrub cover, which might have been caused by the replacement of prior carbon decompositions with the fresh input of shrub leaves. Similarly, the SOC decreased significantly with increasing shrub cover in the grassy matrix, which likely resulted from insufficient fresh plant inputs

  16. Arctic plant ecophysiology and water source utilization in response to altered snow: isotopic (δ18O and δ2H) evidence for meltwater subsidies to deciduous shrubs.

    Science.gov (United States)

    Jespersen, R Gus; Leffler, A Joshua; Oberbauer, Steven F; Welker, Jeffrey M

    2018-06-28

    Warming-linked woody shrub expansion in the Arctic has critical consequences for ecosystem processes and climate feedbacks. The snow-shrub interaction model has been widely implicated in observed Arctic shrub increases, yet equivocal experimental results regarding nutrient-related components of this model have highlighted the need for a consideration of the increased meltwater predicted in expanding shrub stands. We used a 22-year snow manipulation experiment to simultaneously address the unexplored role of snow meltwater in arctic plant ecophysiology and nutrient-related components of the snow-shrub hypothesis. We coupled measurements of leaf-level gas exchange and leaf tissue chemistry (%N and δ 13 C) with an analysis of stable isotopes (δ 18 O and δ 2 H) in soil water, precipitation, and stem water. In deeper snow areas photosynthesis, conductance, and leaf N increased and δ 13 C values decreased in the deciduous shrubs, Betula nana and Salix pulchra, and the graminoid, Eriophorum vaginatum, with the strongest treatment effects observed in deciduous shrubs, consistent with predictions of the snow-shrub hypothesis. We also found that deciduous shrubs, especially S. pulchra, obtained much of their water from snow melt early in the growing season (40-50%), more than either E. vaginatum or the evergreen shrub, Rhododendron tomentosum (Ledum palustre). This result provides the basis for adding a meltwater-focused feedback loop to the snow-shrub interaction model of shrub expansion in the Arctic. Our results highlight the critical role of winter snow in the ecophysiology of Arctic plants, particularly deciduous shrubs, and underline the importance of understanding how global warming will affect the Arctic winter snowpack.

  17. Automated classification of tropical shrub species: a hybrid of leaf shape and machine learning approach

    Directory of Open Access Journals (Sweden)

    Miraemiliana Murat

    2017-09-01

    Full Text Available Plants play a crucial role in foodstuff, medicine, industry, and environmental protection. The skill of recognising plants is very important in some applications, including conservation of endangered species and rehabilitation of lands after mining activities. However, it is a difficult task to identify plant species because it requires specialized knowledge. Developing an automated classification system for plant species is necessary and valuable since it can help specialists as well as the public in identifying plant species easily. Shape descriptors were applied on the myDAUN dataset that contains 45 tropical shrub species collected from the University of Malaya (UM, Malaysia. Based on literature review, this is the first study in the development of tropical shrub species image dataset and classification using a hybrid of leaf shape and machine learning approach. Four types of shape descriptors were used in this study namely morphological shape descriptors (MSD, Histogram of Oriented Gradients (HOG, Hu invariant moments (Hu and Zernike moments (ZM. Single descriptor, as well as the combination of hybrid descriptors were tested and compared. The tropical shrub species are classified using six different classifiers, which are artificial neural network (ANN, random forest (RF, support vector machine (SVM, k-nearest neighbour (k-NN, linear discriminant analysis (LDA and directed acyclic graph multiclass least squares twin support vector machine (DAG MLSTSVM. In addition, three types of feature selection methods were tested in the myDAUN dataset, Relief, Correlation-based feature selection (CFS and Pearson’s coefficient correlation (PCC. The well-known Flavia dataset and Swedish Leaf dataset were used as the validation dataset on the proposed methods. The results showed that the hybrid of all descriptors of ANN outperformed the other classifiers with an average classification accuracy of 98.23% for the myDAUN dataset, 95.25% for the Flavia

  18. FOLIAR ANATOMY OF ENDEMICS SPECIES OF Cattleya (ORCHIDACEAE ENDEMIC FROM GUIANA SHIELD

    Directory of Open Access Journals (Sweden)

    Graciene Tomaz Carneiro

    2017-03-01

    Full Text Available The main goal of this study was characterize the leaf's anatomical aspects of Cattleya jenmanii Rolfe and e C. lawrenceana Rchb. f., describing its anatomical structures in order to increase the knowledge of this endemic species from the region of the Guiana Shield. Besides, it also intended to identify foliar characters to assist in the anatomical comparison of these species. For anatomical study, the material was fixed in FAA and to make the slides we used the usual cut freehand technique and stained with double staining from Safranin with Blue Astra (Safrablau. C. jenmanii and C. lawrenceana has fleshy leaves covered with a thick cuticle. The mesophyll presented dorsiventral with collateral vascular bundles. A large number of bundles of smaller caliber fibers are distributed in the mesophyll poles. Only the presence of a subepidermal layer of fibers differed C. lawrenceana from C. jenmanii. Keyword: Roraima; Guiana Shield; Cattleya; Amazon Basin.

  19. The role of salinity tolerance and competition in the distribution of an endangered desert salt marsh endemic

    Science.gov (United States)

    DeFalco, Lesley; Scoles, Sara; Beamguard, Emily R.

    2017-01-01

    Rare plants are often associated with distinctive soil types, and understanding why endemic species occur in unique environments is fundamental for their management. At Ash Meadows National Wildlife Refuge in southern Nevada, USA, we evaluated whether the limited distribution of endangered Amargosa niterwort (Nitrophila mohavensis) is explained by this species’ tolerance of saline soils on salt-encrusted mud flats compared with the broadly distributed desert saltgrass (Distichlis spicata var. stricta). We simultaneously explored whether niterwort distribution is restricted from expanding due to interspecific competition with saltgrass. Surface soils collected throughout niterwort’s range were unexpectedly less saline with lower extractable Na, seasonal electroconductivity, and Na absorption ratio, and higher soil moisture than in adjacent saltgrass or mixed shrub habitats. Comparison of niterwort and saltgrass growth along an experimental salinity gradient in a greenhouse demonstrated lower growth of niterwort at all but the highest NaCl concentrations. Although growth of niterwort ramets was similar when transplanted into both habitats at the refuge below Crystal Reservoir, niterwort reproductive effort was considerably higher in saltgrass compared to its own habitat, implying reallocation of resources to sexual reproduction to maximize fitness when the probability of ramet mortality increases with greater salinity stress. Saltgrass was not a demonstrated direct competitor of niterwort; however, this species is known to increase soil salinity by exuding salt ions and through litterfall. Niterwort conservation will benefit from protecting hydrological processes that reduce salinity stress and preventing saltgrass colonization into niterwort habitat.

  20. The endemic plants of Micronesia: a geographical checklist and commentary

    Directory of Open Access Journals (Sweden)

    Lorence, D.H.

    2012-05-01

    Full Text Available The Micronesia-Polynesia bioregion is recognized as a global biodiversity hotspot. However, until now estimates regarding the number of endemic plant species for the region were not supported by any comprehensive published work for the region. The results of this study indicate that Micronesia has the world’s highest percentage of plant endemism per square kilometer out of all globally recognized insular biodiversity hotspots. A checklist of all endemic plant species for Micronesia is presented here with their corresponding geographical limits within the region. A summary of previous work and estimates is also provided noting the degree of taxonomic progress in the past several decades. A total of 364 vascular plant species are considered endemic to Micronesia, most of them being restricted to the Caroline Islands with a large percentage restricted to Palau. The checklist includes seven new combinations, one new name, and two unverified names that require additional study to verify endemic status. Overviews of each respective botanical family represented in the list are given including additional information on the Micronesian taxa. Recommendations for future work and potential projects are alluded to throughout the text highlighting major data gaps and very poorly known taxa. The following new combinations and names are made: Cyclosorus carolinensis (Hosokawa Lorence, comb. nov. , Cyclosorusgretheri (W. H. Wagner Lorence, comb. nov., Cyclosorusguamensis (Holttum Lorence, comb. nov., Cyclosorus palauensis (Hosokawa Lorence, comb. nov. , Cyclosorus rupiinsularis (Fosberg Lorence, comb. nov., Dalbergia hosokawae (Hosokawa Costion nom. nov., Syzygium trukensis (Hosokawa Costion & E. Lucas comb. nov.

  1. The migration response to the Legal Arizona Workers Act

    Science.gov (United States)

    Ellis, Mark; Wright, Richard; Townley, Matthew; Copeland, Kristy

    2014-01-01

    The 2008 Legal Arizona Workers Act (LAWA) requires all public and private employers to authenticate the legal status of their workers using the federal employment verification system known as E-Verify. With LAWA, Arizona became the first state to have a universal mandate for employment verification. While LAWA targets unauthorized workers, most of whom are Latino immigrants, other groups could experience LAWA’s effects, such as those who share households with undocumented workers. In addition, employers may seek to minimize their risk of LAWA penalties by not hiring those who appear to them as more likely to be unauthorized, such as naturalized Latino immigrants and US-born Latinos. Existing research has found a reduction in foreign-born Latino employment and population in response to LAWA. This paper asks a different question: have groups that are most likely to be affected by the law migrated to other states? We find a significant and sustained increase in the internal outmigration rate from Arizona of foreign-born, noncitizen Latinos - the group most likely to include the unauthorized - after the passage of LAWA. There was no significant LAWA internal migration response by foreign-born Latino citizens. US-born Latinos showed some signs of a LAWA-induced internal migration response after the law went into effect, but it is not sustained. The results indicate that local and state immigration policy can alter the settlement geography of the foreign born. This leads us to speculate about how immigrant settlement may adjust in the coming years to the intersecting geographies of post-recession economic opportunity and tiered immigration policies. PMID:25018590

  2. 77 FR 22676 - Revisions to the Arizona State Implementation Plan, Pinal County Air Quality Control District

    Science.gov (United States)

    2012-04-17

    ... the Arizona State Implementation Plan, Pinal County Air Quality Control District AGENCY: Environmental... disapproval of a revision to the Pinal County Air Quality Control District portion of the Arizona State... the Control Officer to determine whether the manner of control of fugitive emissions is satisfactory...

  3. Dreamy Draw Dam - Master Plan and Feature Design, New River and Phoenix City Streams, Arizona.

    Science.gov (United States)

    1981-09-01

    and New and Apr. 1983 Agua Fria River below the Arizona Canal Diversion Channel Part 5 - Arizona Canal Diversion Dec. 1983 Channel (including Cave...basin and can be tapped for potable water for recreation use. Electric lines are located approximately 2 miles from the basin at 19th Street and Northern

  4. 76 FR 34181 - Pistachios Grown in California, Arizona, and New Mexico; Proposed Amendments to Marketing Order

    Science.gov (United States)

    2011-06-13

    ...; FV11-983-1 PR] Pistachios Grown in California, Arizona, and New Mexico; Proposed Amendments to... amendments to Marketing Agreement and Order No. 983, which regulates the handling of pistachios grown in California, Arizona, and New Mexico, were proposed by the Administrative Committee for Pistachios (Committee...

  5. 75 FR 68681 - Pistachios Grown in California, Arizona, and New Mexico; Modification of the Aflatoxin Regulations

    Science.gov (United States)

    2010-11-09

    ... FIR] Pistachios Grown in California, Arizona, and New Mexico; Modification of the Aflatoxin..., Arizona, and New Mexico pistachio marketing order (order). The interim rule streamlined the aflatoxin sampling and testing procedures under the order's rules and regulations for pistachios to be shipped for...

  6. 76 FR 9694 - Prevailing Rate Systems; Redefinition of the Northeastern Arizona and Colorado Appropriated Fund...

    Science.gov (United States)

    2011-02-22

    ... 3206-AM33 Prevailing Rate Systems; Redefinition of the Northeastern Arizona and Colorado Appropriated... changes are based on recent consensus recommendations of the Federal Prevailing Rate Advisory Committee to... Northeastern Arizona wage area. The Federal Prevailing Rate Advisory Committee (FPRAC), the national labor...

  7. Safe, Healthy and Ready to Succeed: Arizona School Readiness Key Performance Indicators

    Science.gov (United States)

    Migliore, Donna E.

    2006-01-01

    "Safe, Healthy and Ready to Succeed: Arizona School Readiness Key Performance Indicators" presents a set of baseline measurements that gauge how well a statewide system of school readiness supports is addressing issues that affect Arizona children's readiness for school. The Key Performance Indicators (KPIs) measure the system, rather…

  8. Consequences of Arizona's Immigration Policy on Social Capital among Mexican Mothers with Unauthorized Immigration Status

    Science.gov (United States)

    Valdez, Carmen R.; Padilla, Brian; Valentine, Jessa Lewis

    2013-01-01

    This study explores the consequences of increasingly restrictive immigration policies on social capital among Mexican mothers with unauthorized immigrant status in Arizona. Three focus groups conducted in Arizona explore how mothers' experiences with immigration policies have affected their neighborhood, community, and family ties. Focus group…

  9. Tensions between Policy and Workplace Opportunities in Rural Arizona: Does Public Policy Ignore Social Equality?

    Science.gov (United States)

    Danzig, Arnold; Vandegrift, Judith A.

    Resources available to Arizona through the School-to-Work Opportunities Act will not be concentrated in rural communities, although their educational and economic development needs are proportionately greater. Absent from education reform bills pending in the Arizona House and Senate is any reference to school-to-work transition or any explicit…

  10. GATEWAY Demonstrations: Trial Demonstration of Area Lighting Retrofit, Yuma Border Patrol, Yuma, Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Wilkerson, A. M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McCullough, J. J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-12-31

    Along the Yuma Sector Border Patrol Area in Yuma, Arizona, the GATEWAY program conducted a trial demonstration in which the incumbent quartz metal halide area lighting was replaced with LED at three pole locations at the Yuma Sector Border Patrol Area in Yuma, Arizona. The retrofit was documented to better understand LED technology performance in high-temperature environments.

  11. The Invisible Revolving Door: The Issue of Teacher Attrition in English Language Development Classrooms in Arizona

    Science.gov (United States)

    Heineke, Amy J.

    2018-01-01

    The most restrictive language policy context in the United States, Arizona's monolingual and prescriptive approach to teaching English learners continues to capture national and international attention. Five school years removed from the initial implementation, this study aimed to understand the complexities of Arizona language policy in…

  12. Bark beetle-caused mortality in a drought-affected ponderosa pine landscape in Arizona, USA

    Science.gov (United States)

    Jose F. Negron; Joel D. McMillin; John A. Anhold; Dave Coulson

    2009-01-01

    Extensive ponderosa pine (Pinus ponderosa Dougl. ex Laws.) mortality associated with a widespread severe drought and increased bark beetle (Coleoptera: Curculionidae, Scolytinae) populations occurred in Arizona from 2001 to 2004. A complex of Ips beetles including: the Arizona fivespined ips, Ips lecontei Swaine...

  13. Use and Impact of English-Language Learner Assessment in Arizona

    Science.gov (United States)

    Lawton, Stephen B.

    2009-01-01

    The Arizona English-Language Learner Assessment (AZELLA) is the backbone of Arizona's new English-language learner (ELL) policy in that it is used to assess students' English-language proficiency in order to place them into groups for English-language instruction and to determine when they have become proficient in English. This paper evaluates a…

  14. 78 FR 72579 - Revisions to the Arizona State Implementation Plan, Maricopa County Area

    Science.gov (United States)

    2013-12-03

    ... present several concerns regarding Arizona's efforts to reduce PM 10 pollution. Specifically, the comments... reduce the harmful effects of pollution in Arizona. However, we have no authority to require such... contain any unfunded mandate or significantly or uniquely affect small governments, as described in the...

  15. 77 FR 62452 - Approval and Promulgation of Implementation Plans; State of Arizona; Prevention of Air Pollution...

    Science.gov (United States)

    2012-10-15

    ... Promulgation of Implementation Plans; State of Arizona; Prevention of Air Pollution Emergency Episodes AGENCY... (SIP) revision submitted by the State of Arizona to address the requirements regarding air pollution... air pollution emergency episodes in CAA section 110(a)(2)(G). Section 110(a)(2)(G) requires that each...

  16. Ecology and conservation of the cactus ferruginous pygmy-owl in Arizona

    Science.gov (United States)

    Jean-Luc E. Cartron; Deborah M. Finch

    2000-01-01

    This report is the result of a cooperative effort by the Rocky Mountain Research Station and the USDA Forest Service Region 3, with participation by the Arizona Game and Fish Department and the Bureau of Land Management. It assesses the state of knowledge related to the conservation status of the cactus ferruginous pygmy-owl in Arizona. The population decline of this...

  17. Exploring Arizona K-12 Virtual Educator Experiences and Perspectives Developing Collaborative Learning Communities

    Science.gov (United States)

    Cross, Deborah Iyron

    2015-01-01

    Arizona Online Instruction (AOI) provided an instructional alternative to nearly fifty thousand K-12 students in Arizona during the 2012-2013 school year. Growth in online education underscores the importance of evolving the role of the K-12 virtual teacher as the human agent (Turvey, 2008) demonstrating social learning theory (Bandura, 1977) by…

  18. Achievement Gap Projection for Standardized Testing through Logistic Regression within a Large Arizona School District

    Science.gov (United States)

    Kellermeyer, Steven Bruce

    2011-01-01

    In the last few decades high-stakes testing has become more political than educational. The Districts within Arizona are bound by the mandates of both AZ LEARNS and the No Child Left Behind Act of 2001. At the time of this writing, both legislative mandates relied on the Arizona Instrument for Measuring Standards (AIMS) as State Tests for gauging…

  19. School Finance in Arizona: A State-Local Partnership. A Special Study.

    Science.gov (United States)

    National Education Association, Washington, DC. Commission on Professional Rights and Responsibilities.

    This report discusses the dispute in Arizona over the 1967 legislation regulating educational finance and offers alternatives to that legislation. The document describes factors and issues relevant to an understanding of the present dispute, defines accepted principles of educational finance, provides factual information about Arizona's support of…

  20. High-Risk Populations: The Pimas of Arizona and Mexico.

    Science.gov (United States)

    Schulz, Leslie O; Chaudhari, Lisa S

    2015-03-01

    The purpose of this review is first, to broadly summarize the long-term commitment that began in 1965 to studying type 2 diabetes and obesity through the cooperation of the Pima Indians of Arizona, and second, to discuss the investigations with the Pima Indians of Mexico that started in 1991. The later studies emphasize gene-environment interactions in the pathogenesis of these metabolic disorders. Through the participation of both groups of Pimas, the researchers made key findings with regard to the epidemiology, physiology, clinical assessment and genetics of type 2 diabetes and obesity.

  1. Seismic scanning tunneling macroscope - Elastic simulations and Arizona mine test

    KAUST Repository

    Hanafy, Sherif M.; Schuster, Gerard T.

    2012-01-01

    Elastic seismic simulations and field data tests are used to validate the theory of a seismic scanning tunneling macroscope (SSTM). For nearfield elastic simulation, the SSTM results show superresolution to be better than λ/8 if the only scattered data are used as input data. If the direct P and S waves are muted then the resolution of the scatterer locations are within about λ/5. Seismic data collected in an Arizona tunnel showed a superresolution limit of at least λ/19. These test results are consistent with the theory of the SSTM and suggest that the SSTM can be a tool used by geophysicists as a probe for near-field scatterers.

  2. Salmonella arizonaeInfection In A Guinea Pig Breeding Unit

    OpenAIRE

    GÜREL, Aydın; AYYILDIZ, Gülbin

    1998-01-01

    Salmonella arizonae infection was detected in guinea pigs kept for breeding. Two months old 50 quinea pigs were died in the breedig unit. Three death and 2 live guinea pigs were brought to Veterinary Faculty of İstanbul. The live 2 were euthanasied and necropcy was performed on all guinea pigs. The fluid about 50 cc. in the abdomen, the necrosis and pseudomembranes in the liver and spleen were observed. On histopathology, the foci of various coagulative necrosis were seen in the liver. The...

  3. Arizona Geology Trip - February 25-28, 2008

    Science.gov (United States)

    Thomas, Gretchen A.; Ross, Amy J.

    2008-01-01

    A variety of hardware developers, crew, mission planners, and headquarters personnel traveled to Gila Bend, Arizona, in February 2008 for a CxP Lunar Surface Systems Team geology experience. Participating in this field trip were the CxP Space Suit System (EC5) leads: Thomas (PLSS) and Ross (PGS), who presented the activities and findings learned from being in the field during this KC. As for the design of a new spacesuit system, this allowed the engineers to understand the demands this type of activity will have on NASA's hardware, systems, and planning efforts. The engineers also experienced the methods and tools required for lunar surface activity.

  4. Comparing soil organic carbon dynamics in perennial grasses and shrubs in a saline-alkaline arid region, northwestern China.

    Science.gov (United States)

    Zhou, Yong; Pei, Zhiqin; Su, Jiaqi; Zhang, Jingli; Zheng, Yuanrun; Ni, Jian; Xiao, Chunwang; Wang, Renzhong

    2012-01-01

    Although semi-arid and arid regions account for about 40% of terrestrial surface of the Earth and contain approximately 10% of the global soil organic carbon stock, our understanding of soil organic carbon dynamics in these regions is limited. A field experiment was conducted to compare soil organic carbon dynamics between a perennial grass community dominated by Cleistogenes squarrosa and an adjacent shrub community co-dominated by Reaumuria soongorica and Haloxylon ammodendron, two typical plant life forms in arid ecosystems of saline-alkaline arid regions in northwestern China during the growing season 2010. We found that both fine root biomass and necromass in two life forms varied greatly during the growing season. Annual fine root production in the perennial grasses was 45.6% significantly higher than in the shrubs, and fine root turnover rates were 2.52 and 2.17 yr(-1) for the perennial grasses and the shrubs, respectively. Floor mass was significantly higher in the perennial grasses than in the shrubs due to the decomposition rate of leaf litter in the perennial grasses was 61.8% lower than in the shrubs even though no significance was detected in litterfall production. Soil microbial biomass and activity demonstrated a strong seasonal variation with larger values in May and September and minimum values in the dry month of July. Observed higher soil organic carbon stocks in the perennial grasses (1.32 Kg C m(-2)) than in the shrubs (1.12 Kg C m(-2)) might be attributed to both greater inputs of poor quality litter that is relatively resistant to decay and the lower ability of microorganism to decompose these organic matter. Our results suggest that the perennial grasses might accumulate more soil organic carbon with time than the shrubs because of larger amounts of inputs from litter and slower return of carbon through decomposition.

  5. Different parts, different stories: climate sensitivity of growth is stronger in root collars vs. stems in tundra shrubs.

    Science.gov (United States)

    Ropars, Pascale; Angers-Blondin, Sandra; Gagnon, Marianne; Myers-Smith, Isla H; Lévesque, Esther; Boudreau, Stéphane

    2017-08-01

    Shrub densification has been widely reported across the circumpolar arctic and subarctic biomes in recent years. Long-term analyses based on dendrochronological techniques applied to shrubs have linked this phenomenon to climate change. However, the multi-stemmed structure of shrubs makes them difficult to sample and therefore leads to non-uniform sampling protocols among shrub ecologists, who will favor either root collars or stems to conduct dendrochronological analyses. Through a comparative study of the use of root collars and stems of Betula glandulosa, a common North American shrub species, we evaluated the relative sensitivity of each plant part to climate variables and assessed whether this sensitivity is consistent across three different types of environments in northwestern Québec, Canada (terrace, hilltop and snowbed). We found that root collars had greater sensitivity to climate than stems and that these differences were maintained across the three types of environments. Growth at the root collar was best explained by spring precipitation and summer temperature, whereas stem growth showed weak and inconsistent responses to climate variables. Moreover, sensitivity to climate was not consistent among plant parts, as individuals having climate-sensitive root collars did not tend to have climate-sensitive stems. These differences in sensitivity of shrub parts to climate highlight the complexity of resource allocation in multi-stemmed plants. Whereas stem initiation and growth are driven by microenvironmental variables such as light availability and competition, root collars integrate the growth of all plant parts instead, rendering them less affected by mechanisms such as competition and more responsive to signals of global change. Although further investigations are required to determine the degree to which these findings are generalizable across the tundra biome, our results indicate that consistency and caution in the choice of plant parts are a key

  6. Assessment of selected inorganic constituents in streams in the Central Arizona Basins Study Area, Arizona and northern Mexico, through 1998

    Science.gov (United States)

    Anning, David W.

    2003-01-01

    Stream properties and water-chemistry constituent concentrations from data collected by the National Water-Quality Assessment and other U.S. Geological Survey water-quality programs were analyzed to (1) assess water quality, (2) determine natural and human factors affecting water quality, and (3) compute stream loads for the surface-water resources in the Central Arizona Basins study area. Stream temperature, pH, dissolved-oxygen concentration and percent saturation, and dissolved-solids, suspended-sediment, and nutrient concentration data collected at 41 stream-water quality monitoring stations through water year 1998 were used in this assessment. Water-quality standards applicable to the stream properties and water-chemistry constituent concentration data for the stations investigated in this study generally were met, although there were some exceedences. In a few samples from the White River, the Black River, and the Salt River below Stewart Mountain Dam, the pH in reaches designated as a domestic drinking water source was higher than the State of Arizona standard. More than half of the samples from the Salt River below Stewart Mountain Dam and almost all of the samples from the stations on the Central Arizona Project Canal?two of the three most important surface-water sources used for drinking water in the Central Arizona Basins study area?exceeded the U.S. Environmental Protection Agency drinking water Secondary Maximum Contaminant Level for dissolved solids. Two reach-specific standards for nutrients established by the State of Arizona were exceeded many times: (1) the annual mean concentration of total phosphorus was exceeded during several years at stations on the main stems of the Salt and Verde Rivers, and (2) the annual mean concentration of total nitrogen was exceeded during several years at the Salt River near Roosevelt and at the Salt River below Stewart Mountain Dam. Stream properties and water-chemistry constituent concentrations were related to

  7. Population size, center-periphery, and seed dispersers' effects on the genetic diversity and population structure of the Mediterranean relict shrub Cneorum tricoccon.

    Science.gov (United States)

    Lázaro-Nogal, Ana; Matesanz, Silvia; García-Fernández, Alfredo; Traveset, Anna; Valladares, Fernando

    2017-09-01

    The effect of population size on population genetic diversity and structure has rarely been studied jointly with other factors such as the position of a population within the species' distribution range or the presence of mutualistic partners influencing dispersal. Understanding these determining factors for genetic variation is critical for conservation of relict plants that are generally suffering from genetic deterioration. Working with 16 populations of the vulnerable relict shrub Cneorum tricoccon throughout the majority of its western Mediterranean distribution range, and using nine polymorphic microsatellite markers, we examined the effects of periphery (peripheral vs. central), population size (large vs. small), and seed disperser (introduced carnivores vs. endemic lizards) on the genetic diversity and population structure of the species. Contrasting genetic variation ( H E : 0.04-0.476) was found across populations. Peripheral populations showed lower genetic diversity, but this was dependent on population size. Large peripheral populations showed high levels of genetic diversity, whereas small central populations were less diverse. Significant isolation by distance was detected, indicating that the effect of long-distance gene flow is limited relative to that of genetic drift, probably due to high selfing rates ( F IS  = 0.155-0.887), restricted pollen flow, and ineffective seed dispersal. Bayesian clustering also supported the strong population differentiation and highly fragmented structure. Contrary to expectations, the type of disperser showed no significant effect on either population genetic diversity or structure. Our results challenge the idea of an effect of periphery per se that can be mainly explained by population size, drawing attention to the need of integrative approaches considering different determinants of genetic variation. Furthermore, the very low genetic diversity observed in several small populations and the strong among

  8. Low interannual precipitation has a greater negative effect than seedling herbivory on the population dynamics of a short-lived shrub, Schiedea obovata.

    Science.gov (United States)

    Bialic-Murphy, Lalasia; Gaoue, Orou G

    2018-01-01

    Climate projections forecast more extreme interannual climate variability over time, with an increase in the severity and duration of extreme drought and rainfall events. Based on bioclimatic envelope models, it is projected that changing precipitation patterns will drastically alter the spatial distributions and density of plants and be a primary driver of biodiversity loss. However, many other underlying mechanisms can impact plant vital rates (i.e., survival, growth, and reproduction) and population dynamics. In this study, we developed a size-dependent integral projection model (IPM) to evaluate how interannual precipitation and mollusk herbivory influence the dynamics of a Hawaii endemic short-lived shrub, Schiedea obovata (Caryophyllaceae). Assessing how wet season precipitation effects population dynamics it critical, as it is the timeframe when most of the foliar growth occurs, plants flower and fruit, and seedlings establish. Temporal variation in wet season precipitation had a greater effect than mollusk herbivory on S . obovata population growth rate λ, and the impact of interannual precipitation on vital rates shifted across plant ontogeny. Furthermore, wet season precipitation influenced multiple vital rates in contrasting ways and the effect of precipitation on the survival of larger vegetative and reproductively mature individuals contributed the most to variation in the population growth rate. Among all combination of wet season precipitation and herbivory intensities, the only scenario that led to a growing population was when high wet precipitation was associated with low herbivory. Our study highlights the importance of evaluating how abiotic factors and plant-consumer interactions influence an organism across its life cycle to fully understand the underpinning mechanisms that structure its spatial and temporal distribution and abundance. Our results also illustrate that for short-lived species, like S. obovata , seedling herbivory can have

  9. Adaptive introductions: How multiple experiments and comparisons to wild populations provide insights into requirements for long-term introduction success of an endangered shrub

    Directory of Open Access Journals (Sweden)

    Eric S. Menges

    2016-10-01

    Full Text Available Recovery of an imperiled plant species may require augmentation of existing populations or creation of new ones. Hundreds of such projects have been conducted over the last few decades, but there is a bias in the literature favoring successes over failures. In this paper, we evaluate a series of introductions that experimentally manipulated microhabitat and fire in an adaptive introduction framework. Between 2002 and 2012, we (and our collaborators carried out ten introductions and augmentations of Florida ziziphus Pseudoziziphus (Condalia, Ziziphus celata, a clonal shrub limited to very small populations and narrowly endemic to pyrogenic central Florida sandhills. Six of the introductions were designed as experiments to test hypotheses about how demographic performance was affected by microhabitat, fire, and propagule type. Introduced transplants had high survival (<90% annually, inconsistent growth, and little transition to reproduction, while introduced seeds had low germination and survival. Transplants were more efficient than seeds as translocation propagules. Shaded (vs. open sites supported generally higher transplant and seedling survival and seed germination percentages, but growth responses varied among experiments. Supplemental irrigation increased transplant survival and seed germination, but otherwise seedling and plant survival and growth were not significantly affected. Contrary to expectations based on wild populations, introduced propagules have not been more successful in unshaded sites, suggesting that Florida ziziphus has broader microhabitat preferences than hypothesized. Compared to wild plants, introduced plants had similar survival and responses to fire, slower growth, and more delayed flowering. Introduced plants had no clonal spread. While no introduced population has demonstrated a capacity for long-term viability, one augmented population has flowered and produced viable fruits. Given that Florida ziziphus genets are

  10. Analysis of postfire vegetation dynamics of Mediterranean shrub species based on terrestrial and NDVI data.

    Science.gov (United States)

    Hernández-Clemente, Rocío; Cerrillo, R M Navarro; Hernández-Bermejo, J E; Royo, S Escuin; Kasimis, N A

    2009-05-01

    The present study offers an analysis of regeneration patterns and diversity dynamics after a wildfire, which occurred in 1993 and affected about 7000 ha in southern Spain. The aim of the work was to analyze the rule in the succession of shrub species after fire, relating it to the changes registered in the Normalized Difference Vegetation Index (NDVI). Fractional vegetation cover was recorded from permanent plots in 2000 and 2005. NDVI data related to each time were obtained from Landsat images. Both data sets, from fieldwork and remote sensing, were analyzed through statistical and quantitative analyses and then correlated. Results have permitted the description of the change in plant cover and species composition on a global and plot scale. It can be affirmed that, from the seventh to the twelfth year after the fire, the floristic composition within the burned area remained unchanged at a global level. However, on a smaller scale (plot level), the major shrub species, Ulex parviflorus, Rosmarinus officinalis, and Cistus clusii, underwent significant changes. The regeneration dynamics established by these species conditioned plant species composition and, consequently, diversity indexes such as Shannon (H) and Simpson (D). The changes recorded in the NDVI values corresponding to the surveyed plots were highly correlated with those found in the regrowth of the main species. Areas dominated by U. parviflorus in a senile phase were related to a decrease in NDVI values and an increase in the number of species. This result describes the successional dynamics; the dryness of the main colonizer shrub species is allowing the regrowth and re-establishment of other species. Within the study area, NDVI shows sensitivity to postfire plant cover changes and indirectly expresses the diversity dynamics.

  11. Seedling responses to water pulses in shrubs with contrasting histories of grassland encroachment.

    Directory of Open Access Journals (Sweden)

    Steven R Woods

    Full Text Available Woody plant encroachment into grasslands has occurred worldwide, but it is unclear why some tree and shrub species have been markedly more successful than others. For example, Prosopis velutina has proliferated in many grasslands of the Sonoran Desert in North America over the past century, while other shrub species with similar growth form and life history, such as Acacia greggii, have not. We conducted a glasshouse experiment to assess whether differences in early seedling development could help explain why one species and not the other came to dominate many Sonoran Desert grasslands. We established eight watering treatments mimicking a range of natural precipitation patterns and harvested seedlings 16 or 17 days after germination. A. greggii had nearly 7 times more seed mass than P. velutina, but P. velutina emerged earlier (by 3.0±0.3 d and grew faster (by 8.7±0.5 mg d⁻¹. Shoot mass at harvest was higher in A. greggii (99±6 mg seedling⁻¹ than in P. velutina (74±2 mg seedling⁻¹, but there was no significant difference in root mass (54±3 and 49±2 mg seedling⁻¹, respectively. Taproot elongation was differentially sensitive to water supply: under the highest initial watering pulse, taproots were 52±19 mm longer in P. velutina than in A. greggii. Enhanced taproot elongation under favorable rainfall conditions could give nascent P. velutina seedlings growth and survivorship advantages by helping reduce competition with grasses and maintain contact with soil water during drought. Conversely, A. greggii's greater investment in mass per seed appeared to provide little return in early seedling growth. We suggest that such differences in recruitment traits and their sensitivities to environmental conditions may help explain ecological differences between species that are highly similar as adults and help identify pivotal drivers of shrub encroachment into grasslands.

  12. Photosynthetic response of Eriophorum vaginatum to in situ shrub shading in tussock tundra of northern Alaska

    Science.gov (United States)

    Anderson-Smith, A.; Pattison, R.; Sullivan, P.; Welker, J. M.

    2009-12-01

    Eriophorum vaginatum (Cotton Grass) is an important component of moist acidic tussock tundra, a plant community that appears to be undergoing changes in species composition associated with climate warming. This species is one of the most abundant in the arctic tundra, and provides important forage for caribou in their calving grounds on the Arctic Coastal Plain and along their migratory route through the foothills of Alaska. Recently, remote sensing data, repeat photography and plot-level measurements have indicated that shrub abundance is increasing while Eriophorum abundance is either constant or decreasing. One possible explanation for the reduction of Eriophorum while Betula nana is increasing, is that lower light levels in the taller Betula canopy may be constraining Eriophorum photosynthesis and subsequently reducing plant growth. This study measured the effect of shading on the light response of Eriphorum leaf photosynthesis in four different sites near Toolik Lake Alaska during the summer of 2009. Measurements were taken in: 1) a shrub patch within the drift zone of the ITEX long term snow fence experiment, 2) an LTER shade house (50% shading) built in 1989, 3) water track site 1 and water track site 2 (i.e. control areas with no experimental manipulations) Average photosynthetic rates for Eriophorum at a light level of 800 PAR varied from 3.8 to 10.9 umol m-2 s-1 and were not significantly different in shaded and unshaded areas. This study indicates that shading by shrubs does not appear to be altering the light response of Eriophorum nor does long-term shading by itself eliminate Eriophorum from the community. An alternative explanation for the decline of Eriophorum while Betula increases in abundance under changing climates may be related to plant and soil mineral nutrition, plant water relations or biotic processes involving herbivores.

  13. Analysis of Postfire Vegetation Dynamics of Mediterranean Shrub Species Based on Terrestrial and NDVI Data

    Science.gov (United States)

    Hernández-Clemente, Rocío; Navarro Cerrillo, R. M.; Hernández-Bermejo, J. E.; Escuin Royo, S.; Kasimis, N. A.

    2009-05-01

    The present study offers an analysis of regeneration patterns and diversity dynamics after a wildfire, which occurred in 1993 and affected about 7000 ha in southern Spain. The aim of the work was to analyze the rule in the succession of shrub species after fire, relating it to the changes registered in the Normalized Difference Vegetation Index (NDVI). Fractional vegetation cover was recorded from permanent plots in 2000 and 2005. NDVI data related to each time were obtained from Landsat images. Both data sets, from fieldwork and remote sensing, were analyzed through statistical and quantitative analyses and then correlated. Results have permitted the description of the change in plant cover and species composition on a global and plot scale. It can be affirmed that, from the seventh to the twelfth year after the fire, the floristic composition within the burned area remained unchanged at a global level. However, on a smaller scale (plot level), the major shrub species, Ulex parviflorus, Rosmarinus officinalis, and Cistus clusii, underwent significant changes. The regeneration dynamics established by these species conditioned plant species composition and, consequently, diversity indexes such as Shannon (H) and Simpson (D). The changes recorded in the NDVI values corresponding to the surveyed plots were highly correlated with those found in the regrowth of the main species. Areas dominated by U. parviflorus in a senile phase were related to a decrease in NDVI values and an increase in the number of species. This result describes the successional dynamics; the dryness of the main colonizer shrub species is allowing the regrowth and re-establishment of other species. Within the study area, NDVI shows sensitivity to postfire plant cover changes and indirectly expresses the diversity dynamics.

  14. Bird communities of the arctic shrub tundra of Yamal: habitat specialists and generalists.

    Directory of Open Access Journals (Sweden)

    Vasiliy Sokolov

    Full Text Available BACKGROUND: The ratio of habitat generalists to specialists in birds has been suggested as a good indicator of ecosystem changes due to e.g. climate change and other anthropogenic perturbations. Most studies focusing on this functional component of biodiversity originate, however, from temperate regions. The Eurasian Arctic tundra is currently experiencing an unprecedented combination of climate change, change in grazing pressure by domestic reindeer and growing human activity. METHODOLOGY/PRINCIPAL FINDINGS: Here we monitored bird communities in a tundra landscape harbouring shrub and open habitats in order to analyse bird habitat relationships and quantify habitat specialization. We used ordination methods to analyse habitat associations and estimated the proportions of specialists in each of the main habitats. Correspondence Analysis identified three main bird communities, inhabiting upland, lowland and dense willow shrubs. We documented a stable structure of communities despite large multiannual variations of bird density (from 90 to 175 pairs/km(2. Willow shrub thickets were a hotspot for bird density, but not for species richness. The thickets hosted many specialized species whose main distribution area was south of the tundra. CONCLUSION/SIGNIFICANCE: If current arctic changes result in a shrubification of the landscape as many studies suggested, we would expect an increase in the overall bird abundance together with an increase of local specialists, since they are associated with willow thickets. The majority of these species have a southern origin and their increase in abundance would represent a strengthening of the boreal component in the southern tundra, perhaps at the expense of species typical of the subarctic zone, which appear to be generalists within this zone.

  15. Freezing resistance in Patagonian woody shrubs: the role of cell wall elasticity and stem vessel size.

    Science.gov (United States)

    Zhang, Yong-Jiang; Bucci, Sandra J; Arias, Nadia S; Scholz, Fabian G; Hao, Guang-You; Cao, Kun-Fang; Goldstein, Guillermo

    2016-08-01

    Freezing resistance through avoidance or tolerance of extracellular ice nucleation is important for plant survival in habitats with frequent subzero temperatures. However, the role of cell walls in leaf freezing resistance and the coordination between leaf and stem physiological processes under subzero temperatures are not well understood. We studied leaf and stem responses to freezing temperatures, leaf and stem supercooling, leaf bulk elastic modulus and stem xylem vessel size of six Patagonian shrub species from two sites (plateau and low elevation sites) with different elevation and minimum temperatures. Ice seeding was initiated in the stem and quickly spread to leaves, but two species from the plateau site had barriers against rapid spread of ice. Shrubs with xylem vessels smaller in diameter had greater stem supercooling capacity, i.e., ice nucleated at lower subzero temperatures. Only one species with the lowest ice nucleation temperature among all species studied exhibited freezing avoidance by substantial supercooling, while the rest were able to tolerate extracellular freezing from -11.3 to -20 °C. Leaves of species with more rigid cell walls (higher bulk elastic modulus) could survive freezing to lower subzero temperatures, suggesting that rigid cell walls potentially reduce the degree of physical injury to cell membranes during the extracellular freezing and/or thaw processes. In conclusion, our results reveal the temporal-spatial ice spreading pattern (from stem to leaves) in Patagonian shrubs, and indicate the role of xylem vessel size in determining supercooling capacity and the role of cell wall elasticity in determining leaf tolerance of extracellular ice formation. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Regime shift by an exotic nitrogen-fixing shrub mediates plant facilitation in primary succession.

    Directory of Open Access Journals (Sweden)

    Adriano Stinca

    Full Text Available Ecosystem invasion by non-native, nitrogen-fixing species is a global phenomenon with serious ecological consequences. However, in the Mediterranean basin few studies addressed the impact of invasion by nitrogen-fixing shrubs on soil quality and hydrological properties at local scale, and the possible effects on succession dynamics and ecosystem invasibility by further species. In this multidisciplinary study we investigated the impact of Genista aetnensis (Biv. DC., an exotic nitrogen-fixing shrub, on the Vesuvius Grand Cone (Southern Italy. Specifically, we tested the hypotheses that the invasion of G. aetnensis has a significant impact on soil quality, soil hydrological regime, local microclimate and plant community structure, and that its impact increases during the plant ontogenetic cycle. We showed that G. aetnensis, in a relatively short time-span (i.e. ~ 40 years, has been able to build-up an island of fertility under its canopy, by accumulating considerable stocks of C, N, and P in the soil, and by also improving the soil hydrological properties. Moreover, G. aetnensis mitigates the daily range of soil temperature, reducing the exposure of coexisting plants to extremely high temperatures and water loss by soil evaporation, particularly during the growing season. Such amelioration of soil quality, coupled with the mitigation of below-canopy microclimatic conditions, has enhanced plant colonization of the barren Grand Cone slopes, by both herbaceous and woody species. These results suggest that the invasion of G. aetnensis could eventually drive to the spread of other, more resource-demanding exotic species, promoting alternative successional trajectories that may dramatically affect the local landscape. Our study is the first record of the invasion of G. aetnensis, an additional example of the regime shifts driven by N-fixing shrubs in Mediterranean region. Further studies are needed to identity specific management practices that can

  17. Seedling establishment in a masting desert shrub parallels the pattern for forest trees

    Science.gov (United States)

    Meyer, Susan E.; Pendleton, Burton K.

    2015-05-01

    The masting phenomenon along with its accompanying suite of seedling adaptive traits has been well studied in forest trees but has rarely been examined in desert shrubs. Blackbrush (Coleogyne ramosissima) is a regionally dominant North American desert shrub whose seeds are produced in mast events and scatter-hoarded by rodents. We followed the fate of seedlings in intact stands vs. small-scale disturbances at four contrasting sites for nine growing seasons following emergence after a mast year. The primary cause of first-year mortality was post-emergence cache excavation and seedling predation, with contrasting impacts at sites with different heteromyid rodent seed predators. Long-term establishment patterns were strongly affected by rodent activity in the weeks following emergence. Survivorship curves generally showed decreased mortality risk with age but differed among sites even after the first year. There were no detectable effects of inter-annual precipitation variability or site climatic differences on survival. Intraspecific competition from conspecific adults had strong impacts on survival and growth, both of which were higher on small-scale disturbances, but similar in openings and under shrub crowns in intact stands. This suggests that adult plants preempted soil resources in the interspaces. Aside from effects on seedling predation, there was little evidence for facilitation or interference beneath adult plant crowns. Plants in intact stands were still small and clearly juvenile after nine years, showing that blackbrush forms cohorts of suppressed plants similar to the seedling banks of closed forests. Seedling banks function in the absence of a persistent seed bank in replacement after adult plant death (gap formation), which is temporally uncoupled from masting and associated recruitment events. This study demonstrates that the seedling establishment syndrome associated with masting has evolved in desert shrublands as well as in forests.

  18. A user need study and system plan for an Arizona Natural Resources Information System report to the Arizona state legislature

    Science.gov (United States)

    1980-01-01

    A survey instrument was developed and implemented in order to evaluate the current needs for natural resource information in Arizona and to determine which state agencies have information systems capable of coordinating, accessing and analyzing the data. Data and format requirements were determined for the following categories: air quality, animals, cultural resources, geology, land use, soils, water, vegetation, ownership, and social and economic aspects. Hardware and software capabilities were assessed and a data processing plan was developed. Possible future applications with the next generation LANDSAT were also identified.

  19. Water-quality assessment of the Central Arizona Basins, Arizona and northern Mexico; environmental setting and overview of water quality

    Science.gov (United States)

    Cordy, Gail E.; Rees, Julie A.; Edmonds, Robert J.; Gebler, Joseph B.; Wirt, Laurie; Gellenbeck, Dorinda J.; Anning, David W.

    1998-01-01

    The Central Arizona Basins study area in central and southern Arizona and northern Mexico is one of 60 study units that are part of the U.S. Geological Survey's National Water-Quality Assessment program. The purpose of this report is to describe the physical, chemical, and environmental characteristics that may affect water quality in the Central Arizona Basins study area and present an overview of water quality. Covering 34,700 square miles, the study area is characterized by generally north to northwestward-trending mountain ranges separated by broad, gently sloping alluvial valleys. Most of the perennial rivers and streams are in the northern part of the study area. Rivers and streams in the south are predominantly intermittent or ephemeral and flow in response to precipitation such as summer thunderstorms. Effluent-dependent streams do provide perennial flow in some reaches. The major aquifers in the study area are in the basin-fill deposits that may be as much as 12,000 feet thick. The 1990 population in the study area was about 3.45 million, and about 61 percent of the total was in Maricopa County (Phoenix and surrounding cities). Extensive population growth over the past decade has resulted in a twofold increase in urban land areas and increased municipal water use; however, agriculture remains the major water use. Seventy-three percent of all water with drawn in the study area during 1990 was used for agricultural purposes. The largest rivers in the study area-the Gila, Salt, and Verde-are perennial near their headwaters but become intermittent downstream because of impoundments and artificial diversions. As a result, the Central Arizona Basins study area is unique compared to less arid basins because the mean surface-water outflow is only 528 cubic feet per second from a total drainage area of 49,650 square miles. Peak flows in the northern part of the study area are the result of snowmelt runoff; whereas, summer thunderstorms account for the peak flows in

  20. Endemic pemphigus foliaceus in Venezuela: report of two children.

    Science.gov (United States)

    González, Francisco; Sáenz, Ana Maria; Cirocco, Antonietta; Tacaronte, Inés Maria; Fajardo, Javier Enrique; Calebotta, Adriana

    2006-01-01

    Two native Yanomami children from the Venezuelan Amazonia with erythroderma were hospitalized on our service. Clinical, histologic, and immunofluorescence studies diagnosed endemic pemphigus foliaceous. Human leukocyte antigen class II showed DRB1*04 subtype *0411, which has not been previously associated with this disease. However, it shares a common epitope with all the human leukocyte antigen DRB1 alleles that have been involved in this disease among Brazilian populations. Although this condition is endemic in Brazil, our patients are the first two reported in Venezuela.