WorldWideScience

Sample records for arid lands plants

  1. Herbivore-plant interactions and desertification in arid lands

    Arid lands around the world have experienced or are currently experiencing degradation that is known as desertification. Animal-plant interactions that have an effect on desertification are among the most important function of animals in arid ecosystems. Desertification has been defined as land de...

  2. Oils and rubber from arid land plants

    Johnson, J. D.; Hinman, C. W.

    1980-05-01

    In this article the economic development potentials of Cucurbita species (buffalo gourd and others), Simmondsia chinensis (jojoba), Euphorbia lathyris (gopher plant), and Parthenium argentatum (guayule) are discussed. All of these plants may become important sources of oils or rubber.

  3. Plant-associated microbiomes in arid lands: diversity, ecology and biotechnological potential

    Soussi, Asma

    2015-08-28

    Background: Aridification is a worldwide serious threat directly affecting agriculture and crop production. In arid and desert areas, it has been found that microbial diversity is huge, built of microorganisms able to cope with the environmental harsh conditions by developing adaptation strategies. Plants growing in arid lands or regions facing prolonged abiotic stresses such as water limitation and salt accumulation have also developed specific physiological and molecular stress responses allowing them to thrive under normally unfavorable conditions. Scope: Under such extreme selection pressures, special root-associated bacterial assemblages, endowed with capabilities of plant growth promotion (PGP) and extremophile traits, are selected by the plants. In this review, we provide a general overview on the microbial diversity in arid lands and deserts versus specific microbial assemblages associated with plants. The ecological drivers that shape this diversity, how plant-associated microbiomes are selected, and their biotechnological potential are discussed. Conclusions: Selection and recruitment of the plant associated bacterial assemblages is mediated by the combination of the bio-pedo-agroclimatic conditions and the plant species or varieties. Diversity and functional redundancy of these associated PGPR makes them very active in supporting plant improvement, health and resistance to drought, salt and related stresses. Implementing proper biotechnological applications of the arid and desert-adapted PGPR constitute the challenge to be raised.

  4. Plant-associated microbiomes in arid lands: diversity, ecology and biotechnological potential

    Soussi, Asma; Ferjani, Raoudha; Marasco, Ramona; Guesmi, Amel; Cherif, Hanene; Rolli, Eleonora; Mapelli, Francesca; Ouzari, Hadda Imene; Daffonchio, Daniele; Cherif, Ameur

    2015-01-01

    Selection and recruitment of the plant associated bacterial assemblages is mediated by the combination of the bio-pedo-agroclimatic conditions and the plant species or varieties. Diversity and functional redundancy of these associated PGPR makes them very active in supporting plant improvement, health and resistance to drought, salt and related stresses. Implementing proper biotechnological applications of the arid and desert-adapted PGPR constitute the challenge to be raised.

  5. Emerging crops in the USDA arid lands germplasm collection

    The USDA National Plant Germplasm System maintains collections of several emerging crops for arid lands at the National Arid Land Plant Genetic Resources Unit in Parlier, CA (NALPGRU). The guayule, jojoba, and prickly pear collections are most active in terms of current research and crop development...

  6. Novel ideas for maximising dew collection to aid plant establishment to combat desertification and restore degraded dry and arid lands

    Kotzen, Benz

    2014-05-01

    This paper focuses on the potential of dew to provide water to plants and potentially to people as well in remote and difficult to reach areas where rainfall and underground water cannot be harvested. The combat of desertification and the restoration of degraded and desertified dry and arid lands has never been more urgent. A key practical component of this strategy is the restoration of habitat with planting. But for habitat and planting to survive there needs to be an adequate supply of water. In most cases providing water to the plant's roots is vital. In some areas where habitats have been destroyed, sufficient water is immediately available, for example through seasonal rainfall, or it can be harvested to concentrate adequate supplies of water to the roots. However, in arid and hyper arid areas, as well as in some dryland areas, a consistent and adequate supply of water cannot be provided by any conventional proven method. Thus, as the need to combat desertification and to restore desertified dry and arid land increases, so the need to find novel methods of establishing and maintaining planting and thus habitat increases. In more traditional land management scenarios this can be achieved through manipulating landform on a micro and macro scale, for example, by creating catchments, thereby collecting precipitation and directing it to the plants. Where this cannot be done, other means of water supply are usually required. Bainbridge (2007) and others have shown that supplying water to plants is possible through a number of traditional methods, for example, using clay pots. But most of these techniques require an introduced source of water, for example, obtained through water harvesting methods or by delivering water to site in tanks and by water bowser. This can work but requires continuous manpower. It is expensive and can be physically prohibitive in areas where access is difficult and/or remote. The concept of using dew to supply water in drylands is not new

  7. Use of composts in revegetating arid lands

    Brandt, C.A.; Hendrickson, P.L.

    1991-09-01

    Compost has been suggested as a soil amendment for arid lands at the US Department of Energy's Hanford Site in southeastern Washington State. The operating contractor of the site, Westinghouse Hanford Company, requested that the Pacific Northwest Laboratory conduct a literature review to compile additional information on the use of compost amendments and their benefits. This report provides background information on the factors needed for plant growth and the consequences of severe soil disturbance. This report also discussed the characteristics of composts relative to other amendments and how they each affect plant growth. Finally,regulatory requirements that could affect land application of sludge-based compost on the Hanford Site are reviewed.

  8. Hydrologic alteration affects aquatic plant assemblages in an arid-land river

    Vinson, Mark; Hestmark, Bennett; Barkworth, Mary E.

    2014-01-01

    We evaluated the effects of long-term flow alteration on primary-producer assemblages. In 1962, Flaming Gorge Dam was constructed on the Green River. The Yampa River has remained an unregulated hydrologically variable river that joins the Green River 100 km downstream from Flaming Gorge Dam. In the 1960s before dam construction only sparse occurrences of two macroalgae, Cladophora and Chara, and no submerged vascular plants were recorded in the Green and Yampa rivers. In 2009–2010, aquatic plants were abundant and widespread in the Green River from the dam downstream to the confluence with the Yampa River. The assemblage consisted of six vascular species, Elodea canadensis, Myriophyllum sibiricum, Nasturtium officinale,Potamogeton crispus, Potamogeton pectinatus, and Ranunculus aquatilis, the macroalgae Chara and Cladophora, and the bryophyte, Amblystegium riparium. In the Green River downstream from the Yampa River, and in the Yampa River, only sparse patches of Chara and Cladophora growing in the splash zone on boulders were collected. We attribute the observed changes in the Green River to an increase in water transparency and a reduction in suspended and bed-load sediment and high flow disturbances. The lack of hydrophyte colonization downstream from the confluence with the Yampa River has implications for understanding tributary amelioration of dam effects and for designing more natural flow-regime schedules downstream from large dams.

  9. Arid and semiarid land stewardship: A 10-year review of accomplishments and contributions of the lnternational Arid Lands Consortium

    Peter F. Ffolliott; Jeffrey O. Dawson; James T. Fisher; Itshack Moshe; Darrell W. DeBoers; Timothy. E. Fulbright; John Tracy; Abdullah Al Musa; Carter Johnson; Jim P. M. Chamie

    2001-01-01

    The International Arid Lands Consortium (IALC) was established in 1990 to promote research, education, and training activities related to the development, management, and restoration or reclamation of arid and semiarid lands worldwide. The IALC, a leading international organization, supports ecological sustainability and development of arid and semiarid lands. Building...

  10. Domesticated proboscidea parviflora: a potential oilseed crop for arid lands

    Berry, J.; Bretting, P.K.; Nabhan, G.P.; Weber, C.

    1981-01-01

    Wild and domesticated Proboscidea parviflora were evaluated as oilseed crops for arid lands through chemical and biological analyses. Domesticated plants grown in the Sonoran desert bore seed containing 35-40 per cent oil and 23-27 per cent protein. Yield per hectare was estimated at 1000 kg of oil and 675 kg of protein, quantities which compare favourably with other crops. An ephemeral life cycle and certain characteristics of the fruit and seed allow this plant to grow in xeric habitats unsuitable for many other plants. Several Proboscidea species hybridize with P. parviflora and could be used in future crop breeding. Rapid germination and higher oil and protein content of seed make the domesticated P. parviflora superior to the wild form as a crop. Domesticated P. parviflora thus shows promise as an oilseed crop for the Sonoran Desert and possibly for other arid regions. (Refs. 22).

  11. International Arid Lands Consortium: Better land stewardship in water and watershed management

    Peter F. Ffolliott; James T. Fisher; Menachem Sachs; Darrell W. DeBoer; Jeffrey O. Dawson; Timothy E. Fulbright; John Tracy

    2000-01-01

    The International Arid Lands Consortium (IALC) was established in 1990 to promote research, education, and training for the development, management, and restoration of arid and semi-arid lands throughout the world. One activity of IALC members and cooperators is to support research and development and demonstration projects that enhance management of these fragile...

  12. How Sustainable are Engineered Rivers in Arid Lands?

    Jurgen Schmandt

    2013-06-01

    Full Text Available Engineered rivers in arid lands play an important role in feeding the world’s growing population. Each continent has rivers that carry water from distant mountain sources to fertile soil downstream where rainfall is scarce. Over the course of the last century most rivers in arid lands have been equipped with large engineering structures that generate electric power and store water for agriculture and cities. This has changed the hydrology of the rivers. In this paper we discuss how climate variation, climate change, reservoir siltation, changes in land use and population growth will challenge the sustainability of engineered river systems over the course of the next few decades. We use the Rio Grande in North America, where we have worked with Mexican and American colleagues, to describe our methodology and results. Similar work is needed to study future water supply and demand in engineered rivers around the world.

  13. Can biochar be used as a seed coating to improve native plant germination and growth in arid conditions?

    Mary I. Williams; R. Kasten Dumroese; Deborah S. Page-Dumroese; Stuart P. Hardegree

    2016-01-01

    Direct seeding is a common large-scale restoration practice for revegetating arid and semi-arid lands, but success can be limited by moisture and temperature. Seed coating technologies that use biochar may have the potential to overcome moisture and temperature limitations on native plant germination and growth. Biochar is a popular agronomic tool for improving soil...

  14. Woody plants in agro-ecosystems of semi-arid regions

    Breman, H.; Kessler, J.J.

    1995-01-01

    A quantitative analysis of the role of woody plants in semi-arid regions, focusing on the Sahel and Sudan zones in West-Africa, is given for the assessment of their benefits in agro-sylvopastoral land-use systems with productive and sustainability objectives.

  15. New Technologies to Reclaim Arid Lands User's Manual

    W. K. Ostler

    2002-10-01

    Approximately 70 percent of all U.S. military training lands are located in arid and semi-arid areas. Training activities in such areas frequently adversely affect vegetation, damaging plants and reducing the resilience of vegetation to recover once disturbed. Fugitive dust resulting from a loss of vegetation creates additional problems for human health, increasing accidents due to decreased visibility, and increasing maintenance costs for roads, vehicles, and equipment. Under conventional technologies to mitigate these impacts, it is estimated that up to 35 percent of revegetation projects in arid areas will fail due to unpredictable natural environmental conditions, such as drought, and reclamation techniques that were inadequate to restore vegetative cover in a timely and cost-effective manner. New reclamation and restoration techniques are needed in desert ranges to help mitigate the adverse effects of military training and other activities to arid-land environments. In 1999, a cooperative effort between the U.S. Department of Energy (DOE), the US. Department of Defense (DoD), and selected university scientists was undertaken to focus on mitigating military impacts in arid lands. As arid lands are impacted due to DoD and DOE activities, biological and soil resources are gradually lost and the habitat is altered. A conceptual model of that change in habitat quality is described for varying levels of disturbance in the Mojave Desert. As the habitat quality degrades and more biological and physical resources are lost from training areas, greater costs are required to return the land to sustainable levels. The purpose of this manual is to assist land managers in recognizing thresholds associated with habitat degradation and provide reclamation planning and techniques that can reduce the costs of mitigation for these impacted lands to ensure sustainable use of these lands. The importance of reclamation planning is described in this manual with suggestions about

  16. Mitigating Climate Change in the Arid Lands of Namibia

    Schneider, Martin B.; Sorensen, Marten

    2014-05-01

    Mitigating Climate Change in the Arid Lands of Namibia Namibia is the most arid country south of the Sahara, with scarce rainfall and perennial rivers only at its borders, > 80% of the area relies solely on groundwater. This has had devastating economic effects limiting opportunities for sustainable rural livelihoods that keep the population majority living below the World Bank poverty line (IFAD, 2013). A primary example of climatic variability which affects agrarian productivity is increased bush encroachment of Namibia's arid grazing land. The result has been a severe biodiversity loss, increased desertification and diminished water-use efficiency and underground water tables. Given these factors, Namibia's arid lands provide a unique opportunity to assess and test innovative / appropriate adaptation and mitigation strategies. Working toward sustainable management, restoration, and maintenance of balanced, resilient arid ecosystems in Namibia will also be a means to support and expand economic sectors incl. opportunities for job creation and potentially provide a model for similar arid regions. Main vegetation zones are: desert (46%), savannah (37%), and dry woodlands and forests (17%), i.e. management strategies currently used by rural communities. 2. Capture and assess cultural and gender dimensions of management strategies within stakeholder groups using participatory approaches. 3. Determine science-based alternatives for adaptive land management strategies and test their acceptability to local communities and within the current policy framework. 4. Integrate identified indigenous knowledge with appropriate science and new emerging technologies to develop a training toolkit of effective strategies relevant to all stakeholders. 5. Utilize training sessions, education workshops, curriculum revisions, and appropriate information and communication technologies (ICTs) including social media outlets to disseminate the toolkit strategies. 6. Apply a modified logic

  17. Productivity of selected plant species adapted to arid regions. [Crassulacean metabolizing plants; Agave deserti and Ferocactus acanthodes

    Nobel, P.S.

    1980-01-01

    The biomass potential of selected arid region species for alcohol production merits careful consideration. The basis for this interest is the current low agronomic use of arid lands and the potential productivity of certain species adapted to these lands. Plants displaying Crassulacean acid metabolism (CAM) are particularly interesting with reference to biomass for fuel in regions with low rainfall, because plants with this photosynthetic process are strikingly efficient in water requirements. For CAM plants, CO/sub 2/ fixation occurs primarily at night, when tissue surface temperature and hence transpirational water loss is less than daytime values. For Agave deserti in the Sonoran desert, the water-use efficiency (mass of CO/sub 2/ fixed/mass of water transpired) over an entire year is an order of magnitude or more larger than for C-3 and C-4 plants. This indicates how well adapted CAM species are to arid regions. The potential productivity per unit land area of CAM plants is fairly substantial and, therefore, of considerable economic interest for arid areas where growth of agricultural plants is minimal.

  18. Aridity, desalination plants and tourism in the eastern Canary Islands

    José-León García-Rodríguez

    2016-05-01

    Full Text Available The islands of Lanzarote and Fuerteventura are the easternmost of the Canary Islands, and are located on the southern edge of the temperate zone, in the subtropical anticyclone belt. With less than 150 mm of rainfall a year, they are classified as an arid zone. Their inhabitants have devised original agricultural systems to combat the aridity, although low yields have historically limited socio-economic development and population growth. These systems were used until the introduction of seawater desalination plants and the arrival of tourism in the last third of the twentieth century, which improved living standards for the local population but also led to a cultural transition. Nevertheless, these farming systems have left behind an important regional heritage, with an environmental and scenic value that has played an integral role in the latest phase of development. The systems have become a tourist attraction and have been central to the two islands being designated biosphere reserves by UNESCO. This article aims to analyse the main socioeconomic and land-use changes that have come about as a result of desalination technology.

  19. Regional Cost Estimates for Reclamation Practices on Arid and Semiarid Lands; TOPICAL

    W. K. Ostler

    2002-01-01

    The U.S. Army uses the Integrated Training Area Management program for managing training land. One of the major objectives of the Integrated Training Area Management program has been to develop a method for estimating training land carrying capacity in a sustainable manner. The Army Training and Testing Area Carrying Capacity methodology measures training load in terms of Maneuver Impact Miles. One Maneuver Impact Mile is the equivalent impact of an M1A2 tank traveling one mile while participating in an armor battalion field training exercise. The Army Training and Testing Area Carrying Capacity methodology is also designed to predict land maintenance costs in terms of dollars per Maneuver Impact Mile. The overall cost factor is calculated using the historical cost of land maintenance practices and the effectiveness of controlling erosion. Because land maintenance costs and effectiveness are influenced by the characteristics of the land, Army Training and Testing Area Carrying Capacity cost factors must be developed for each ecological region of the country. Costs for land maintenance activities are presented here for the semiarid and arid regions of the United States. Five ecoregions are recognized, and average values for reclamation activities are presented. Because there are many variables that can influence costs, ranges for reclamation activities are also presented. Costs are broken down into six major categories: seedbed preparation, fertilization, seeding, planting, mulching, and supplemental erosion control. Costs for most land reclamation practices and materials varied widely within and between ecological provinces. Although regional cost patterns were evident for some practices, the patterns were not consistent between practices. For the purpose of estimating land reclamation costs for the Army Training and Testing Area Carrying Capacity methodology, it may be desirable to use the ''Combined Average'' of all provinces found in the last row of each table

  20. Transcriptome profiling of the Australian arid-land plant Eremophila serrulata (A.DC.) Druce (Scrophulariaceae) for the identification of monoterpene synthases.

    Kracht, Octavia Natascha; Ammann, Ann-Christin; Stockmann, Julia; Wibberg, Daniel; Kalinowski, Jörn; Piotrowski, Markus; Kerr, Russell; Brück, Thomas; Kourist, Robert

    2017-04-01

    Plant terpenoids are a large and highly diverse class of metabolites with an important role in the immune defense. They find wide industrial application as active pharmaceutical ingredients, aroma and fragrance compounds. Several Eremophila sp. derived terpenoids have been documented. To elucidate the terpenoid metabolism, the transcriptome of juvenile and mature Eremophila serrulata (A.DC.) Druce (Scrophulariaceae) leaves was sequenced and a transcript library was generated. We report on the first transcriptomic dataset of an Eremophila plant. IlluminaMiSeq sequencing (2 × 300 bp) revealed 7,093,266 paired reads, which could be assembled to 34,505 isogroups. To enable detection of terpene biosynthetic genes, leaves were separately treated with methyl jasmonate, a well-documented inducer of plant secondary metabolites. In total, 21 putative terpene synthase genes were detected in the transcriptome data. Two terpene synthase isoenzymatic genes, termed ES01 and ES02, were successfully expressed in E. coli. The resulting proteins catalyzed the conversion of geranyl pyrophosphate, the universal substrate of monoterpene synthases to myrcene and Z-(b)-ocimene, respectively. The transcriptomic data and the discovery of the first terpene synthases from Eremophila serrulata are the initial step for the understanding of the terpene metabolism in this medicinally important plant genus. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Integrated Spatial Models of Non Native Plant Invasion, Fire Risk, and Wildlife Habitat to Support Conservation of Military and Adjacent Lands in the Arid Southwest

    2015-12-01

    Schwalbe 2002). The result is a vastly altered fire regime for desert regions. As a consequence of human activities and the prevalence of invasive...the most prevalent predictors for Brassica presence (6 of 12 variables), with three models associated with mean fall NDVI, one with maximum fall NDVI...plant diversity assessment using a pixel nested plot design: a case study in Beaver Meadows, Rocky Mountain National Park, Colorado, USA. Diversity

  2. Close-out report Fitzner-Eberhardt Arid Lands Ecology Reserve remedial action, Hanford, Washington

    1996-04-01

    The Fitzner-Eberhardt Arid Lands Ecology (ALE) Reserve consists of 312 km 2 (120 mi 2 ) of shrub-steppe land on the western edge of the Hanford Site. It is located south of Highway 240 and east of the point where the Yakima River borders the site. The land was set aside as a natural research area in 1967 by the Atomic Energy Commission. Historically tribal land, the area was homesteaded by pioneers before it was taken by the federal government in 1943 as a security buffer to protect the Hanford Site defense production facilities. One antiaircraft artillery battery (latter converted to a Nike missile site) was located on this land; plutonium production plants or storage facilities were never built there. A more complete account can be found in the Preliminary Assessment Screening (PAS) Report for the Arid Lands Ecology Reserve, Hanford. With the recent change in mission at the Hanford Site from plutonium production to environmental cleanup, much attention has been given to releasing clean tracts of land for other uses. The ALE Reserve is one such tract of land. The existing areas of contamination in the ALE Reserve were considered to be small. In March 1993, the U.S. Department of Energy (DOE), the Environmental Protection Agency (EPA), and the Washington State Department of Ecology (Ecology) signed and Agreement in Principle in which they agreed to expedite cleanup of the ALE Reserve. Cleanup activities and a draft close-out report were to be completed by October 1994. Additionally, DOE proposed to mitigate hazards that may pose a physical threat to wildlife or humans

  3. Performance comparison of land change modeling techniques for land use projection of arid watersheds

    S.M. Tajbakhsh

    2018-07-01

    Full Text Available The change of land use/land cover has been known as an imperative force in environmental alteration, especially in arid and semi-arid areas. This research was mainly aimed to assess the validity of two major types of land change modeling techniques via a three dimensional approach in Birjand urban watershed located in an arid climatic region of Iran. Thus, a Markovian approach based on two suitability and transition potential mappers, i.e. fuzzy analytic hierarchy process and artificial neural network-multi layer perceptron was used to simulate land use map. Validation metrics, quantity disagreement, allocation disagreement and figure of merit in a three-dimensional space were used to perform model validation. Utilizing the fuzzy-analytic hierarchy processsimulation of total landscape in the target point 2015, quantity error, the figure of merit and allocation error were 2%, 18.5% and 8%, respectively. However, Artificial neural network-multi layer perceptron simulation led to a marginal improvement in figure of merit, i.e. 3.25%.

  4. Meaningful traits for grouping plant species across arid ecosystems.

    Bär Lamas, Marlene Ivonne; Carrera, A L; Bertiller, M B

    2016-05-01

    Grouping species may provide some degree of simplification to understand the ecological function of plants on key ecosystem processes. We asked whether groups of plant species based on morpho-chemical traits associated with plant persistence and stress/disturbance resistance reflect dominant plant growth forms in arid ecosystems. We selected twelve sites across an aridity gradient in northern Patagonia. At each site, we identified modal size plants of each dominant species and assessed specific leaf area (SLA), plant height, seed mass, N and soluble phenol concentration in green and senesced leaves at each plant. Plant species were grouped according with plant growth forms (perennial grasses, evergreen shrubs and deciduous shrubs) and plant morphological and/or chemical traits using cluster analysis. We calculated mean values of each plant trait for each species group and plant growth form. Plant growth forms significantly differed among them in most of the morpho-chemical traits. Evergreen shrubs were tall plants with the highest seed mass and soluble phenols in leaves, deciduous shrubs were also tall plants with high SLA and the highest N in leaves, and perennial grasses were short plants with high SLA and low concentration of N and soluble phenols in leaves. Grouping species by the combination of morpho-chemical traits yielded 4 groups in which species from one growth form prevailed. These species groups differed in soluble phenol concentration in senesced leaves and plant height. These traits were highly correlated. We concluded that (1) plant height is a relevant synthetic variable, (2) growth forms adequately summarize ecological strategies of species in arid ecosystems, and (3) the inclusion of plant morphological and chemical traits related to defenses against environmental stresses and herbivory enhanced the potential of species grouping, particularly within shrubby growth forms.

  5. Land–atmosphere feedbacks amplify aridity increase over land under global warming

    Berg, Alexis; Findell, Kirsten; Lintner, Benjamin; Giannini, Alessandra; Seneviratne, Sonia I.; van den Hurk, Bart; Lorenz, Ruth; Pitman, Andy; Hagemann, Stefan; Meier, Arndt; Cheruy, Frédérique; Ducharne, Agnès; Malyshev, Sergey; Milly, Paul C. D.

    2016-01-01

    The response of the terrestrial water cycle to global warming is central to issues including water resources, agriculture and ecosystem health. Recent studies indicate that aridity, defined in terms of atmospheric supply (precipitation, P) and demand (potential evapotranspiration, Ep) of water at the land surface, will increase globally in a warmer world. Recently proposed mechanisms for this response emphasize the driving role of oceanic warming and associated atmospheric processes. Here we show that the aridity response is substantially amplified by land–atmosphere feedbacks associated with the land surface’s response to climate and CO2 change. Using simulations from the Global Land Atmosphere Coupling Experiment (GLACE)-CMIP5 experiment, we show that global aridity is enhanced by the feedbacks of projected soil moisture decrease on land surface temperature, relative humidity and precipitation. The physiological impact of increasing atmospheric CO2 on vegetation exerts a qualitatively similar control on aridity. We reconcile these findings with previously proposed mechanisms by showing that the moist enthalpy change over land is unaffected by the land hydrological response. Thus, although oceanic warming constrains the combined moisture and temperature changes over land, land hydrology modulates the partitioning of this enthalpy increase towards increased aridity.

  6. Combining Sustainable Land Management Technologies to Combat Land Degradation and Improve Rural Livelihoods in Semi-arid Lands in Kenya.

    Mganga, K Z; Musimba, N K R; Nyariki, D M

    2015-12-01

    Drylands occupy more than 80% of Kenya's total land mass and contribute immensely to the national economy and society through agriculture, livestock production, tourism, and wild product harvesting. Dryland ecosystems are areas of high climate variability making them vulnerable to the threats of land degradation. Consequently, agropastoralists inhabiting these ecosystems develop mechanisms and technologies to cope with the impacts of climate variability. This study is aimed to; (1) determine what agropastoralists inhabiting a semi-arid ecosystem in Kenya attribute to be the causes and indicators of land degradation, (2) document sustainable land management (SLM) technologies being undertaken to combat land degradation, and (3) identify the factors that influence the choice of these SLM technologies. Vegetation change from preferred indigenous forage grass species to woody vegetation was cited as the main indicator of land degradation. Land degradation was attributed to recurrent droughts and low amounts of rainfall, overgrazing, and unsustainable harvesting of trees for fuelwood production. However, despite the challenges posed by climate variability and recurrent droughts, the local community is engaging in simple SLM technologies including grass reseeding, rainwater harvesting and soil conservation, and dryland agroforestry as a holistic approach combating land degradation and improving their rural livelihoods. The choice of these SLM technologies was mainly driven by their additional benefits to combating land degradation. In conclusion, promoting such simple SLM technologies can help reverse the land degradation trend, improve agricultural production, food security including access to food, and subsequently improve livelihoods of communities inhabiting dryland ecosystems.

  7. Combining Sustainable Land Management Technologies to Combat Land Degradation and Improve Rural Livelihoods in Semi-arid Lands in Kenya

    Mganga, K. Z.; Musimba, N. K. R.; Nyariki, D. M.

    2015-12-01

    Drylands occupy more than 80 % of Kenya's total land mass and contribute immensely to the national economy and society through agriculture, livestock production, tourism, and wild product harvesting. Dryland ecosystems are areas of high climate variability making them vulnerable to the threats of land degradation. Consequently, agropastoralists inhabiting these ecosystems develop mechanisms and technologies to cope with the impacts of climate variability. This study is aimed to; (1) determine what agropastoralists inhabiting a semi-arid ecosystem in Kenya attribute to be the causes and indicators of land degradation, (2) document sustainable land management (SLM) technologies being undertaken to combat land degradation, and (3) identify the factors that influence the choice of these SLM technologies. Vegetation change from preferred indigenous forage grass species to woody vegetation was cited as the main indicator of land degradation. Land degradation was attributed to recurrent droughts and low amounts of rainfall, overgrazing, and unsustainable harvesting of trees for fuelwood production. However, despite the challenges posed by climate variability and recurrent droughts, the local community is engaging in simple SLM technologies including grass reseeding, rainwater harvesting and soil conservation, and dryland agroforestry as a holistic approach combating land degradation and improving their rural livelihoods. The choice of these SLM technologies was mainly driven by their additional benefits to combating land degradation. In conclusion, promoting such simple SLM technologies can help reverse the land degradation trend, improve agricultural production, food security including access to food, and subsequently improve livelihoods of communities inhabiting dryland ecosystems.

  8. Response of deep soil moisture to land use and afforestation in the semi-arid Loess Plateau, China

    Yang, Lei; Wei, Wei; Chen, Liding; Mo, Baoru

    2012-12-01

    SummarySoil moisture is an effective water source for plant growth in the semi-arid Loess Plateau of China. Characterizing the response of deep soil moisture to land use and afforestation is important for the sustainability of vegetation restoration in this region. In this paper, the dynamics of soil moisture were quantified to evaluate the effect of land use on soil moisture at a depth of 2 m. Specifically, the gravimetric soil moisture content was measured in the soil layer between 0 and 8 m for five land use types in the Longtan catchment of the western Loess Plateau. The land use types included traditional farmland, native grassland, and lands converted from traditional farmland (pasture grassland, shrubland and forestland). Results indicate that the deep soil moisture content decreased more than 35% after land use conversion, and a soil moisture deficit appeared in all types of land with introduced vegetation. The introduced vegetation decreased the soil moisture content to levels lower than the reference value representing no human impact in the entire 0-8 m soil profile. No significant differences appeared between different land use types and introduced vegetation covers, especially in deeper soil layers, regardless of which plant species were introduced. High planting density was found to be the main reason for the severe deficit of soil moisture. Landscape management activities such as tillage activities, micro-topography reconstruction, and fallowed farmland affected soil moisture in both shallow and deep soil layers. Tillage and micro-topography reconstruction can be used as effective countermeasures to reduce the soil moisture deficit due to their ability to increase soil moisture content. For sustainable vegetation restoration in a vulnerable semi-arid region, the plant density should be optimized with local soil moisture conditions and appropriate landscape management practices.

  9. Development of corrective measures technology for shallow land burial facilities at arid sites

    Nyhan, J.W.; Abeele, W.V.; Perkins, B.A.; Lane, L.J.

    1984-01-01

    The field research program involving corrective measure technologies for arid shallow land burial (SLB) sites is described. Soil erosion and infiltration of water into a simulated trench cap with various surface treatments was measured and compared with similar data from agricultural systems across the United States. Field testing of biointrustion barriers at closed-out waste disposal sites at Los Alamos and in the experimental clusters are reported. The final results of an experiment designed to measure the extent of contaminant transport to the surface of a SLB facility, and the influence of plants on this relationship, are presented. An experiment designed to determine the effects of subsidence on the performance of a cobble-gravel biobarrier system is described and current field data are presented. 11 references, 11 figures, 5 tables

  10. Native-plant amendments and topsoil addition enhance soil function in post-mining arid grasslands.

    Kneller, Tayla; Harris, Richard J; Bateman, Amber; Muñoz-Rojas, Miriam

    2018-04-15

    One of the most critical challenges faced in restoration of disturbed arid lands is the limited availability of topsoil. In post-mining restoration, alternative soil substrates such as mine waste could be an adequate growth media to alleviate the topsoil deficit, but these materials often lack appropriate soil characteristics to support the development and survival of seedlings. Thus, addition of exogenous organic matter may be essential to enhance plant survival and soil function. Here, we present a case study in the arid Pilbara region (north-west Western Australia), a resource-rich area subject to intensive mining activities. The main objective of our study was to assess the effects of different restoration techniques such as soil reconstruction by blending available soil materials, sowing different compositions of plant species, and addition of a locally abundant native soil organic amendment (Triodia pungens biomass) on: (i) seedling recruitment and growth of Triodia wiseana, a dominant grass in Australian arid ecosystems, and (ii) soil chemical, physical, and biological characteristics of reconstructed soils, including microbial activity, total organic C, total N, and C and N mineralisation. The study was conducted in a 12-month multifactorial microcosms setting in a controlled environment. Our results showed that the amendment increased C and N contents of re-made soils, but these values were still lower than those obtained in the topsoil. High microbial activity and C mineralisation rates were found in the amended waste that contrasted the low N mineralisation but this did not translate into improved emergence or survival of T. wiseana. These results suggest a short- or medium-term soil N immobilisation caused by negative priming effect of fresh un-composted amendment on microbial communities. We found similar growth and survival rates of T. wiseana in topsoil and a blend of topsoil and waste (50:50) which highlights the importance of topsoil, even in a

  11. Potential of native shrubs Haloxylon salicornicum and Calligonum Polygonoides for restoration of degraded lands in Arid Western Rajasthan, India.

    Rathore, V S; Singh, J P; Bhardwaj, S; Nathawat, N S; Kumar, Mahesh; Roy, M M

    2015-01-01

    Shrub-induced soil property spatial heterogeneity is common in arid and semi-arid ecosystems and aids desertified land restoration. However, the effectiveness of this technique may rely on the plant species used and the habitat conditions present. To assess the degree to which planting two native species, Haloxylon salicornicum and Calligonum polygonoides, facilitates degraded land restoration, soil and herbaceous plant community properties were measured 7 years after planting. Soil samples were extracted at two depths (0-5 and 5-20 cm) from three sub-habitats, i.e., under the shrub canopy, from alleys between shrubs and from the open area. Shrub planting increased the quantity of silt + clay content (30-39 %); enhanced water holding capacities (24-30 %); increased the levels of organic carbon (48-69 %), available nitrogen (31-47 %), available phosphorus (32-41 %), and electrical conductivity (21-33 %); and decreased the pH (7-12 %) and bulk density levels (5-6 %) in the surface layer of soils beneath the canopy. Soil property changes were more significant at the surface (0-5 cm) than in the deeper layer (5-20 cm), and were more pronounced under H. salicornicum than under C. polygonoides. Furthermore, the density and biomass levels of herbaceous plants were 1.1 to 1.2 and 1.4 to 1.6 times greater, respectively, in the shrub alleys than in open area. H. salicornicum induced more robust soil amelioration and herbaceous plant facilitative properties than did C. polygonoides. Artificially planting these shrubs may thus be employed to restore degraded areas of arid regions.

  12. Land cover/land use change in semi-arid Inner Mongolia: 1992-2004

    John, Ranjeet; Chen Jiquan; Lu Nan; Wilske, Burkhard, E-mail: ranjeet.john@utoledo.ed [Department of Environmental Sciences, University of Toledo, Toledo, OH 43606 (United States)

    2009-10-15

    The semi-arid grasslands in Inner Mongolia (IM) are under increasing stress owing to climate change and rapid socio-economic development in the recent past. We investigated changes in land cover/land use and landscape structure between 1992 and 2004 through the analysis of AVHRR and MODIS derived land cover data. The scale of analysis included the regional level (i.e. the whole of IM) as well as the level of the dominant biomes (i.e. the grassland and desert). We quantified proportional change, rate of change and the changes in class-level landscape metrics using the landscape structure analysis program FRAGSTATS. The dominant land cover types, grassland and barren, 0.47 and 0.27 million km{sup 2}, respectively, have increased proportionally. Cropland and urban land use also increased to 0.15 million km{sup 2} and 2197 km{sup 2}, respectively. However, the results further indicated increases in both the homogeneity and fragmentation of the landscape. Increasing homogeneity was mainly related to the reduction in minority cover types such as savanna, forests and permanent wetlands and increasing cohesion, aggregation index and clumpy indices. Conversely, increased fragmentation of the landscape was based on the increase in patch density and the interspersion/juxtaposition index (IJI). It is important to note the socio-economic growth in this fragile ecosystem, manifested by an increasing proportion of agricultural and urban land use not just at the regional level but also at the biome level in the context of regional climate change and increasing water stress.

  13. Land cover/land use change in semi-arid Inner Mongolia: 1992-2004

    John, Ranjeet; Chen Jiquan; Lu Nan; Wilske, Burkhard

    2009-01-01

    The semi-arid grasslands in Inner Mongolia (IM) are under increasing stress owing to climate change and rapid socio-economic development in the recent past. We investigated changes in land cover/land use and landscape structure between 1992 and 2004 through the analysis of AVHRR and MODIS derived land cover data. The scale of analysis included the regional level (i.e. the whole of IM) as well as the level of the dominant biomes (i.e. the grassland and desert). We quantified proportional change, rate of change and the changes in class-level landscape metrics using the landscape structure analysis program FRAGSTATS. The dominant land cover types, grassland and barren, 0.47 and 0.27 million km 2 , respectively, have increased proportionally. Cropland and urban land use also increased to 0.15 million km 2 and 2197 km 2 , respectively. However, the results further indicated increases in both the homogeneity and fragmentation of the landscape. Increasing homogeneity was mainly related to the reduction in minority cover types such as savanna, forests and permanent wetlands and increasing cohesion, aggregation index and clumpy indices. Conversely, increased fragmentation of the landscape was based on the increase in patch density and the interspersion/juxtaposition index (IJI). It is important to note the socio-economic growth in this fragile ecosystem, manifested by an increasing proportion of agricultural and urban land use not just at the regional level but also at the biome level in the context of regional climate change and increasing water stress.

  14. Hypogeous fungi from Southern Spanish semi-arid lands

    Honrubia, M.; Cano, A.; Molina-Niñirola, C.

    1992-01-01

    Six hypogeous fungi of Ascomycotina and Basidiomycotina have been studied from semiarid zones in Southern Spain. Melanogaster variegatus (Vitt.) Tul. is recorded for the first time from Spain. Picoa juniperi Vitt. and Terfezia claveryi Chat. are revealed as the most frequent species in semi-arid

  15. Deep Soil Recharge in Arid and Semi-Arid Regions: New Evidences in MU-US Sandy Land of China

    Cheng, Y.; Yang, W.; Zhan, H.

    2017-12-01

    Precipitation induced recharge is an important source of groundwater budget but it is very difficult to quantify in arid and semiarid regions. In this study, a newly invented lysimeter was used to monitor deep soil recharge (DSR) under 200 cm depth in MU-US sandy land in western China under three kinds of landforms (mobile dune, semi-fixed dune, and fixed dune). We found that the annual DSRs in such three different kinds of landforms varied significantly. Specifically, the annual DSRs were 224.1 mm (50.5% of the annual precipitation), 71.1 mm (50.5% of the annual precipitation), and 1.3 mm (0.3% of the annual precipitation) in mobile dune, semi-fixed dune, and fixed dune, respectively. We also found that vegetation coverage and precipitation pattern significantly affected DSR. A 24-hr precipitation event with the precipitation amount greater than 8 mm was able to infiltrate soil deeper than 200 cm and contributed to ground water recharge directly. Vegetation was a dominant factor influencing infiltration in the fixed sand dune. Our research revealed that precipitation induced DSR in arid and semi-arid regions was a complex process that required long-term monitoring and innovative system analysis of interrelated factors such as precipitation strength and pattern, meteorological parameters, and dynamic soil moisture. Key words: Precipitation pattern, sand dune groundwater, deep soil recharge, infiltration.

  16. The Soil-Land use System in a Sand Spit Area in the Semi-Arid ...

    The Soil-Land use System in a Sand Spit Area in the Semi-Arid Coastal Savanna Region of Ghana – Development, Sustainability and Threats. ... The investigation comprises soil profile descriptions and analyses on the dominant soil type on the sand spit, measurement of electrical conductivity of well water and in the soil, ...

  17. The potential of intercropping food crops and energy crop to improve productivity of a degraded agriculture land in arid tropics

    I.K.D. Jaya

    2014-04-01

    Full Text Available Degraded agricultural lands in the arid tropics have low soil organic carbon (SOC and hence low productivity. Poor farmers that their livelihoods depend highly on these types of lands are suffering. Cropping strategies that are able to improve the soil productivity are needed. In the present study, some intercropping models of food crops with bio-energy crop of castor (Ricinus communis L. were tested to assess their potential to improve the degraded land productivity. The intercropping models were: (1 castor - hybrid maize, (2 castor – short season maize, (3 castor – mungbean, and (4 castor –short season maize – mungbean. The results show that yields of the component crops in monoculture were relatively the same as in intercropping, resulted in a high Land Equivalent Ratio (LER. The highest LER (3.07 was calculated from intercropping castor plants with short season maize crops followed by mungbean with intercropping productivity of IDR 15,097,600.00 ha-1. Intercropping has a great potential to improve degraded agriculture land productivity and castor is a promising plant to improve biodiversity and area coverage on the land.

  18. Active old-field restoration in the most arid lands of the Great Basin

    Restoration of former agricultural fields can be challenging, especially in arid systems, where factors such as wind erosion, water stress, soil alteration, and competition from weeds can strongly affect plant establishment and growth. Experiments were conducted in two former agricultural fields in ...

  19. Effectiveness of post-fire seeding at the Fitzner-Eberhardt Arid Land Ecology Reserve, Washington

    Wirth, Troy A.; Pyke, David A.

    2011-01-01

    In August 2007, the Milepost 17 and Wautoma fires burned a combined total of 77,349 acres (31,302 hectares) of the Fitzner-Eberhardt Arid Land Ecology Reserve (ALE), part of the Hanford Reach National Monument administered by the U.S. Fish and Wildlife Service (USFWS) Mid-Columbia National Wildlife Refuge. In 2009, the USFWS implemented a series of seeding and herbicide treatments to mitigate potential negative consequences of these fires, including mortality of native vegetation, invasion of Bromus tectorum (cheatgrass), and soil erosion. Treatments included combinations of seeding (drill and aerial), herbicides, and one of six different mixtures of species. Artemisia tridentata ssp. wyomingensis (Wyoming big sagebrush) also was planted by hand in a small area in the southern end of the fire perimeter. Due to differences in plant communities prior to the fire and the multiple treatments applied, treatments were grouped into five treatment associations including mid-elevation aerial seedings, low-elevation aerial seedings, low-elevation drill seedings, high-elevation drill seeding, and no seeding treatments. Data collected at the mid-elevation aerial seedings indicate that the seeding did not appear to increase the density of seedlings compared to the non-seeded area in 2010. At the low-elevation aerial seedings, there were significantly more seedlings at seeded areas as compared to non-seeded areas. Low densities of existing perennial plants probably fostered a low-competition environment enabling seeds to germinate and emerge in 2010 during adequate moisture. Low-elevation drill seedings resulted in significant emergence of seeded grasses in 2009 and 2010 and forbs in 2010. This was likely due to adequate precipitation and that the drill seeding assured soil-to-seed contact. At the high-elevation drill seeding, which was implemented in 2009, there were a high number of seedlings in 2010. Transplanting of A. tridentata following the fires resulted in variable

  20. Land cover controls on summer discharge and runoff solution chemistry of semi-arid urban catchments

    Gallo, Erika L.; Brooks, Paul D.; Lohse, Kathleen A.; McLain, Jean E. T.

    2013-04-01

    SummaryRecharge of urban runoff to groundwater as a stormwater management practice has gained importance in semi-arid regions where water resources are scarce and urban centers are growing. Despite this trend, the importance of land cover in controlling semi-arid catchment runoff quantity and quality remains unclear. Here we address the question: How do land cover characteristics control the amount and quality of storm runoff in semi-arid urban catchments? We monitored summertime runoff quantity and quality from five catchments dominated by distinct urban land uses: low, medium, and high density residential, mixed use, and commercial. Increasing urban land cover increased runoff duration and the likelihood that a rainfall event would result in runoff, but did not increase the time to peak discharge of episodic runoff. The effect of urban land cover on hydrologic responses was tightly coupled to the magnitude of rainfall. At distinct rainfall thresholds, roads, percent impervious cover and the stormwater drainage network controlled runoff frequency, runoff depth and runoff ratios. Contrary to initial expectations, runoff quality did not vary in repose to impervious cover or land use. We identified four major mechanisms controlling runoff quality: (1) variable solute sourcing due to land use heterogeneity and above ground catchment connectivity; (2) the spatial extent of pervious and biogeochemically active areas; (3) the efficiency of overland flow and runoff mobilization; and (4) solute flushing and dilution. Our study highlights the importance of the stormwater drainage systems characteristics in controlling urban runoff quantity and quality; and suggests that enhanced wetting and in-stream processes may control solute sourcing and retention. Finally, we suggest that the characteristics of the stormwater drainage system should be integrated into stormwater management approaches.

  1. Small-Scale Farmer Initiatives for Irrigating the Arid and Semi-Arid Lands of Kenya

    Itabari, J.K.; Nguluu, S.N.; Ikombo, B.M.; Wambua, J.M.; Gichangi, E.M.; Maina, J.N.

    1999-01-01

    A survey was undertaken in Machakos , Kitui, Makueni, Mwingi and Baringo districts to Identify the major systems currently being employed with a view to assessing there performance. In Machakos, Kitui, Makueni and Mwingi districts, the main sources of water were small earth dams (micro dams), with water harnessed from run off and nearby uncultivated or grazing lands. In Baringo district, the main source of water was adam constructed across a seasonal river called Wesegess. All micro dams were excavated by their owners using mainly manual labour and skills acquired from neighbours, supplemented by owner's initiates. In the areas in Eastern province, only horticultural crops are irrigated. In Baringo district, grain and horticultural crops than in grain crops underscoring their higher water demand and importance in the household cas flow. The main irrigation system employed in the Eastern province was spot, whereas furrows was widely used in Baringo district. Availability of water within the farm freed labour from fetching water long distances and shortened walking distances for livestock. It also facilitated cultivation of high value crops to improve farmers' household cash economy

  2. Development of land degradation spectral indices in a semi-arid Mediterranean ecosystem

    Chabrillat, Sabine; Kaufmann, Hermann J.; Palacios-Orueta, Alicia; Escribano, Paula; Mueller, Andreas

    2004-10-01

    The goal of this study is to develop remote sensing desertification indicators for drylands, in particular using the capabilities of imaging spectroscopy (hyperspectral imagery) to derive soil and vegetation specific properties linked to land degradation status. The Cabo de Gata-Nijar Natural Park in SE Spain presents a still-preserved semiarid Mediterranean ecosystem that has undergone several changes in landscape patterns and vegetation cover due to human activity. Previous studies have revealed that traditional land uses, particularly grazing, favoured in the Park the transition from tall arid brush to tall grass steppe. In the past ~40 years, tall grass steppes and arid garrigues increased while crop field decreased, and tall arid brushes decreased but then recovered after the area was declared a Natural Park in 1987. Presently, major risk is observed from a potential effect of exponential tourism and agricultural growth. A monitoring program has been recently established in the Park. Several land degradation parcels presenting variable levels of soil development and biological activity were defined in summer 2003 in agricultural lands, calcareous and volcanic areas, covering the park spatial dynamics. Intensive field spectral campaigns took place in Summer 2003 and May 2004 to monitor inter-annual changes, and assess the landscape spectral variability in spatial and temporal dimension, from the dry to the green season. Up to total 1200 field spectra were acquired over ~120 targets each year in the land degradation parcels. The targets were chosen to encompass the whole range of rocks, soils, lichens, and vegetation that can be observed in the park. Simultaneously, acquisition of hyperspectral images was performed with the HyMap sensor. This paper presents preliminary results from mainly the field spectral campaigns. Identifying sources of variability in the spectra, in relation with the ecosystem dynamics, will allow the definition of spectral indicators of

  3. Long-term effect of land use change on soil quality: Afforestation and land abandonment in semi-arid Spain

    Zethof, Jeroen; Cammeraat, Erik; Nadal-Romero, Estela

    2016-04-01

    Soils under the Mediterranean climate are vulnerable for degradation, especially after land abandonment. Abandonment is an important factor in the Mediterranean landscape as vegetation regeneration is hampered due to the characteristic semi-arid and sub-humid Mediterranean climate regime. During the past 70 year extensive afforestation projects have been conducted with the aim to protect landscapes and soils against degradation. While large investments are still being made, little is known about the impact of afforestation on soil quality on a longer time scale. During the past decade, there is a growing interest in qualifying and quantifying the carbon storage in soils by such afforestation projects, to get a better understanding of the carbon cycle and look for possibilities to fixate atmospheric CO2 in the soil. It is generally accepted that afforestation projects will increase the soil carbon pool, but data on this process is scarce. Therefore an intensive fieldwork has been carried out in Murcia, southeastern Spain to study the effects of land abandonment and afforestation on soil quality along a chronosequence and included two afforested areas (from the early '70s and 1993). The Pinus halepensis trees were planted in rows, for which the underlying calcrete was broken. Samples were taken to study changes in soil quality (Aggregate stability, Corg, N, P, K, Na), Soil Organic Carbon (SOC) stocks and soil hydraulic properties, such as infiltration and water retention, between the afforestation projects, abandoned agricultural plots of similar age, semi-natural vegetation, cereal crop fields and almond orchards. As the natural vegetation is characterized by a spotted pattern of bare areas and trees, forming so-called "islands of fertility", both bare and vegetation covered sub-sites were sampled. First results showed a positive effect of both land abandonment and afforestation on the soil aggregation. Especially the 40-year-old plots showed underneath trees

  4. Plant Communities Suitable for Green Roofs in Arid Regions

    Rachel Gioannini

    2018-05-01

    , and root-to-shoot dry weight ratio (0.45 than native Euphorbia. At the end of year 2, the relative growth rate (RGR of native Euphorbia of 0.15 g·g−1·d−1 was greater than that of Sedum. While the native succulent had a smaller root biomass, its greater RWC and RGR would indicate it had better plant water status and grew faster than the non-native. The lack of differences in plant performance regardless of assignment to monoculture or community would imply that communities and monocultures are equally suitable for arid region green roofs.

  5. Spatial patterns and natural recruitment of native shrubs in a semi-arid sandy land.

    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.

  6. Preface paper to the Semi-Arid Land-Surface-Atmosphere (SALSA) Program special issue

    Goodrich, D.C.; Chehbouni, A.; Goff, B.; MacNish, B.; Maddock, T.; Moran, S.; Shuttleworth, W.J.; Williams, D.G.; Watts, C.; Hipps, L.H.; Cooper, D.I.; Schieldge, J.; Kerr, Y.H.; Arias, H.; Kirkland, M.; Carlos, R.; Cayrol, P.; Kepner, W.; Jones, B.; Avissar, R.; Begue, A.; Bonnefond, J.-M.; Boulet, G.; Branan, B.; Brunel, J.P.; Chen, L.C.; Clarke, T.; Davis, M.R.; DeBruin, H.; Dedieu, G.; Elguero, E.; Eichinger, W.E.; Everitt, J.; Garatuza-Payan, J.; Gempko, V.L.; Gupta, H.; Harlow, C.; Hartogensis, O.; Helfert, M.; Holifield, C.; Hymer, D.; Kahle, A.; Keefer, T.; Krishnamoorthy, S.; Lhomme, J.-P.; Lagouarde, J.-P.; Lo, Seen D.; Luquet, D.; Marsett, R.; Monteny, B.; Ni, W.; Nouvellon, Y.; Pinker, R.; Peters, C.; Pool, D.; Qi, J.; Rambal, S.; Rodriguez, J.; Santiago, F.; Sano, E.; Schaeffer, S.M.; Schulte, M.; Scott, R.; Shao, X.; Snyder, K.A.; Sorooshian, S.; Unkrich, C.L.; Whitaker, M.; Yucel, I.

    2000-01-01

    The Semi-Arid Land-Surface-Atmosphere Program (SALSA) is a multi-agency, multi-national research effort that seeks to evaluate the consequences of natural and human-induced environmental change in semi-arid regions. The ultimate goal of SALSA is to advance scientific understanding of the semi-arid portion of the hydrosphere-biosphere interface in order to provide reliable information for environmental decision making. SALSA approaches this goal through a program of long-term, integrated observations, process research, modeling, assessment, and information management that is sustained by cooperation among scientists and information users. In this preface to the SALSA special issue, general program background information and the critical nature of semi-arid regions is presented. A brief description of the Upper San Pedro River Basin, the initial location for focused SALSA research follows. Several overarching research objectives under which much of the interdisciplinary research contained in the special issue was undertaken are discussed. Principal methods, primary research sites and data collection used by numerous investigators during 1997-1999 are then presented. Scientists from about 20 US, five European (four French and one Dutch), and three Mexican agencies and institutions have collaborated closely to make the research leading to this special issue a reality. The SALSA Program has served as a model of interagency cooperation by breaking new ground in the approach to large scale interdisciplinary science with relatively limited resources.

  7. Filling the interspace—restoring arid land mosses: source populations, organic matter, and overwintering govern success

    Condon, Lea; Pyke, David A.

    2016-01-01

    Biological soil crusts contribute to ecosystem functions and occupy space that could be available to invasive annual grasses. Given disturbances in the semiarid shrub steppe communities, we embarked on a set of studies to investigate restoration potential of mosses in sagebrush steppe ecosystems. We examined establishment and growth of two moss species common to the Great Basin, USA: Bryum argenteum and Syntrichia ruralis from two environmental settings (warm dry vs. cool moist). Moss fragments were inoculated into a third warm dry setting, on bare soil in spring and fall, both with and without a jute net and with and without spring irrigation. Moss cover was monitored in spring seasons of three consecutive years. Both moss species increased in cover over the winter. When Bryum received spring irrigation that was out of sync with natural precipitation patterns, moss cover increased and then crashed, taking two seasons to recover. Syntrichia did not respond to the irrigation treatment. The addition of jute net increased moss cover under all conditions, except Syntrichia following fall inoculation, which required a second winter to increase in cover. The warm dry population of Bryum combined with jute achieved on average 60% cover compared to the cool moist population that achieved only 28% cover by the end of the study. Differences were less pronounced for Syntrichia where moss from the warm dry population with jute achieved on average 51% cover compared to the cool moist population that achieved 43% cover by the end of the study. Restoration of arid land mosses may quickly protect soils from erosion while occupying sites before invasive plants. We show that higher moss cover will be achieved quickly with the addition of organic matter and when moss fragments originate from sites with a climate that is similar to that of the restoration site.

  8. Field studies of erosion-control technologies for arid shallow land-burial sites at Los Alamos

    Nyhan, J.W.; Abeele, W.V.; DePoorter, G.L.; Hakonson, T.E.; Perkins, B.A.; Foster, G.R.

    1983-01-01

    The field research program involving corrective measures technologies for arid shallow land-burial sites is described. Research performed for a portion of this task, the identification, evaluation, and modeling of erosion control technologies, is presented in detail. In a joint study with USDA-ARS, soil erosion and infiltration of water into a simulated trench cap with various surface treatments was measured and compared with data from undisturbed soil surfaces with natural plant cover. The distribution of soil particles in the runoff was measured for inclusion in CREAMS (a field scale model for Chemicals, Runoff and Erosion from Agricultural Management Systems). Neutron moisture gauge data collected beneath the erosion plots are presented to show the seasonal effects of the erosion control technologies on the subsurface component of water balance. 12 references, 4 figures, 4 tables

  9. Development of spatial heterogeneity in vegetation and soil properties after land abandonment in a semi-arid ecosystem

    Lesschen, J.P.; Cammeraat, L.H.; Kooijman, A.M.; van Wesemael, B.

    2008-01-01

    To mitigate erosion on abandoned fields in semi-arid ecosystems, it is important to understand how vegetation and soil properties and patterns develop after land abandonment. Our objective was to investigate the development of spatial heterogeneity in vegetation and soil properties after land

  10. Survey of Revegetated Areas on the Fitzner/Eberhardt Arid Lands Ecology Reserve: Status and Initial Monitoring Results

    Downs, Janelle L.; Link, Steven O.; Rozeboom, Latricia L.; Durham, Robin E.; Cruz, Rico O.; Mckee, Sadie A.

    2011-09-01

    During 2010, the U.S. Department of Energy (DOE), Richland Operations Office removed a number of facilities and debris from the Fitzner/Eberhardt Arid Lands Ecology Reserve (ALE), which is part of the Hanford Reach National Monument (HRNM). Revegetation of disturbed sites is necessary to stabilize the soil, reduce invasion of these areas by exotic weeds, and to accelerate re-establishment of native plant communities. Seven revegetation units were identified on ALE based on soils and potential native plant communities at the site. Native seed mixes and plant material were identified for each area based on the desired plant community. Revegetation of locations affected by decommissioning of buildings and debris removal was undertaken during the winter and early spring of 2010 and 2011, respectively. This report describes both the details of planting and seeding for each of the units, describes the sampling design for monitoring, and summarizes the data collected during the first year of monitoring. In general, the revegetation efforts were successful in establishing native bunchgrasses and shrubs on most of the sites within the 7 revegetation units. Invasion of the revegetation areas by exotic annual species was minimal for most sites, but was above initial criteria in 3 areas: the Hodges Well subunit of Unit 2, and Units 6 and 7.

  11. Status of corrective measures technology for shallow land burial at arid sites

    Abeele, W.V.; Nyhan, J.W.; Drennon, B.J.; Lopez, E.A.; Herrera, W.J.; Langhorst, G.J.

    1985-01-01

    The field research program involving corrective measure technologies for arid shallow land burial sites is described. Soil erosion and infiltration of water into a simulated trench cap with various surface treatments was measured and compared with similar data from agricultural systems across the United States. Report of field testing of biointrusion barriers continues at a closed-out waste disposal site at Los Alamos. Final results of an experiment designed to determine the effects of subsidence on the performance of a cobble-gravel biobarrier system are reported, as well as the results of hydrologic modeling activities involving biobarrier systems. 11 refs., 10 figs

  12. Spatiotemporal soil and saprolite moisture dynamics across a semi-arid woody plant gradient

    Woody plant cover has increased 10-fold over the last 140+ years in many parts of the semi-arid western USA. Woody plant cover can alter the timing and amount of plant available moisture in the soil and saprolite. To assess spatiotemporal subsurface moisture dynamics over two water years in a snow-d...

  13. Decomposition of standing litter in arid grasslands: Interactions between sunlight, non-rainfall moisture, microbes, and plant traits

    Logan, J. R. V.; Jacobson, P. J.; Jacobson, K. M.; Evans, S.

    2017-12-01

    Although arid lands make up 40% of the Earth's land surface, we still lack a strong understanding of carbon cycling and plant decomposition in these systems. One reason for this is that field studies typically only focus on decomposition at or below the ground surface even though standing dead litter (material that has not yet fallen to the ground) accounts for more than 50% of total necromass in many of these systems. While recent work has begun to recognize the important and unique aspects of standing litter decomposition, few studies have investigated specific mechanisms controlling rates of mass loss. We hypothesized that initial photodegradation of the outer plant cuticle of standing litter is an important determinant of litter decomposition because this process increases moisture absorption and subsequent opportunities for biological decomposition. Our preliminary results offer support for this hypothesis. We found that standing grass stems with their cuticles artificially removed had greater water absorbance and more than 400% greater mass loss over a 6-month period relative to controls with intact cuticles. Additionally, spectroscopic measurements of cuticle integrity showed damage to the litter surface after a period of extended photodegradation, allowing increased moisture uptake during simulated fog/dew events. These findings are especially important in the context of recent work by us and others showing that non-rainfall moisture (fog, dew, and water vapor) plays a much larger role in arid land decomposition than previously thought. Improving our understanding of the mechanisms driving decomposition of standing litter will enable us to develop a more predictive understanding of carbon storage in arid lands.

  14. Spectral mixture analysis (SMA and change vector analysis (CVA methods for monitoring and mapping land degradation/desertification in arid and semiarid areas (Sudan, using Landsat imagery

    Abdelrahim A.M. Salih

    2017-04-01

    Full Text Available The severe Sahel catastrophe in 1968–1974 as well as repeated famines and food shortage that have hit many African countries during the 1970s have highlighted the need for further research concerning land degradation and environmental monitoring in arid and semi-arid areas. Land degradation, and desertification processes in arid and semi-arid environment were increased in the last four decades, especially in the developing countries like Sudan. To test to what extent remote sensing and geographical information science (GIS methodologies and techniques could be used for monitoring changes in arid and semi-arid regions and environment, these methodologies have long been suggested as a time and cost-efficient method. In this frame, spectral Mixture Analysis (SMA, Object-based oriented classification (Segmentation, and Change Vector Analysis are recently much recommended as a most suitable method for monitoring and mapping land cover changes in arid and semi-arid environment. Therefor the aim of this study is to use these methods and techniques for environmental monitoring with emphasis on desertification and to find model that can describe and map the status and rate of desertification processes and land cover changes in semi-arid areas in White Nile State (Sudan by using multi-temporal imagery of the Landsat satellite TM (1987, TM (2000, and ETM+ (2014 respectively. The paper also discusses and evaluates the efficiency of the adapted methodologies in monitoring the land degradation processes and changes in the arid and semi-arid regions.

  15. On the sensitivity of Land Surface Temperature estimates in arid irrigated lands using MODTRAN

    Rosas, Jorge; Houborg, Rasmus; McCabe, Matthew

    2015-01-01

    Land surface temperature (LST) derived from thermal infrared (TIR) satellite data has been reliably used as a remote indicator of evapotranspiration (ET) and surface moisture status. However, in order to retrieve the ET with an accuracy approaching

  16. Water Resources Response to Climate and Land-Cover Changes in a Semi-Arid Watershed, New Mexico, USA

    Joonghyeok Heo

    2015-01-01

    Full Text Available This research evaluates a climate-land cover-water resources interconnected system in a semi-arid watershed with minimal human impact from 1970 - 2009. We found _ increase in temperature and 10.9% decrease in precipitation. The temperature exhibited a lower increase trend and precipitation showed a similar decrease trend compared to previous studies. The dominant land-cover change trend was grass and forest conversion into bush/shrub and developed land and crop land into barren and grass land. These alterations indicate that changes in temperature and precipitation in the study area may be linked to changes in land cover, although human intervention is recognized as the major land-cover change contributor for the short term. These alterations also suggest that decreasing human activity in the study area leads to developed land and crop land conversion into barren and grass land. Hydrological responses to climate and land-cover changes for surface runoff, groundwater discharge, soil water content and evapotranspiration decreased by 10.2, 10.0, 4.1, and 10.5%, respectively. Hydrological parameters generally follow similar trends to that of precipitation in semi-arid watersheds with minimal human development. Soil water content is sensitive to land-cover change and offset relatively by the changes in precipitation.

  17. Recycled Urban Wastewater for Irrigation of Jatropha curcas L. in Abandoned Agricultural Arid Land

    María Dorta-Santos

    2014-10-01

    Full Text Available In a global context in which obtaining new energy sources is of paramount importance, the production of biodiesel from plant crops is a potentially viable alternative to the use of fossil fuels. Among the species used to produce the raw material for biodiesel, Jatropha curcas L. (JCL has enjoyed increased popularity in recent years, due partly to its ability to grow in degraded zones and under arid and semi-arid conditions. The present study evaluates the potential for JCL production under irrigation with non-conventional water resources in abandoned agricultural soils of the island of Fuerteventura (Canary Islands, Spain, which is one of the most arid parts of the European Union. JCL growth and productivity are compared during the first 39 months of cultivation in two soil types (clay-loam and sandy-loam and with two irrigation water qualities: recycled urban wastewater (RWW and desalinated brackish water (DBW. The results indicate that JCL growth (in terms of plant height and stem diameter was significantly influenced both by soil type and water quality, with better development observed in the sandy-loam soil under RWW irrigation. Productivity, measured as cumulative seed production, was not affected by soil type but was affected by water quality. Production under RWW irrigation was approximately seven times greater than with DBW (mean ~2142 vs. 322 kg·ha−1. The higher nutrient content, especially P, K and Mg, and lower B content of the RWW were found to be key factors in the greater productivity observed under irrigation with this type of water.

  18. Sustainable land cover and terrain modification to enhance convection and precipitation in the arid region of the United Arab Emirates

    Wulfmeyer, V.; Branch, O.; Adebabseh, A.; Temimi, M.

    2017-12-01

    Irrigated plantations and modified terrain can provide a sustainable means of enhancing convective rainfall in arid regions like the United Arab Emirates, or UAE, and can be used to aid ongoing cloud seeding operations through the geographic-localization of seedable cloud formation. The first method, the planting of vast irrigated plantations of hardy desert shrubs, can lead to wind convergence and vertical mixing through increased roughness and modified radiative balances. When upper-air atmospheric instability is present, these phenomena can initiate convection. The second method, increasing the elevation of moderate-sized mountains, is based on the correlation between elevation and the number of summertime convection initiation events observed in the mountains of the UAE and Oman. This augmentation of existing orographic features should therefore increase the likelihood and geographic range of convection initiation events. High-resolution simulations provide a powerful means of assessing the likely impacts of land surface modifications. Previous convection-permitting simulations have yielded some evidential support for these hypotheses, but higher resolutions down to 1 km provide more detail regarding convective processes and land surface representation. Using seasonal simulations with the WRF-NOAHMP land-atmosphere model at a 2.5 km resolution, we identify frequent zones of convergence and atmospheric instability in the UAE and select interesting cases. Using these results, as well as an agricultural feasibility study, we identify optimal plantation positions within the UAE. We then run realistic plantation scenarios for single case studies at 1 km resolution. Using the same cases, we simulate the impact of augmenting mountain elevations on convective processes, with the augmentation being achieved through GIS-based modification of the terrain data. For both methods, we assess the impacts quantitatively and qualitatively, and assess key processes and

  19. The phyllophagous of woody plants of genus Ulmus in protective plantings of arid zone

    Belitskaya, M. N.; Gribust, I. R.; Nefed'eva, E. E.; Filimonova, O. S.; Golovanova, M. A.

    2018-01-01

    Creating of long-lasting, normally developing plantings on the urbanized territories in the arid zones is difficult. The main tree species are elm (Fam. Ulmaceae - more than 70% of tree composition). They have a high drought and salt tolerance, rapid growth. They are widely used in the creation of artificial forest plantings in steppes and deserts. The main part of the plantations was created in the 50-60 years of 20th century. Today the aging of plants is observing. Trees of this age lose their physiological and decorative potential as well as resistance to pests under intensive anthropogenic impact. At the forest pathology research about 90 % of the plants of elm species of plantings of various types and categories were identified to be in poor condition. Leaf-eating pests play an active role in the deterioration of their sanitary state. Xanthogaleruca luteola (Müller, 1766), Cladius ulmi (Linnaeus, 1758), and Aproceros leucopoda (Takeuchi, 1939) have a special harmfulness as well as the regularity of the local centers among the mass phyllophagous of plants of the family. The last two species were discovered in artificial plantations for the first time. The destructive effect of those pests on certain types of elm plants is uneven.

  20. Technology development for the design of shallow land burial facilities at arid sites

    Nyhan, J.W.; Abeele, W.V.; Cokal, E.J.; Perkins, B.A.; Lane, L.J.

    1984-01-01

    The field research program involving technology development for arid shallow land burial (SLB) sites is described. Field tests of biointrusion barriers at waste disposal sites and in experimental plots at Los Alamos are reported. Results of completed and on-going experiments with migration barriers for water and contaminant movement are presented. An envelope wick experiment for subsurface water management is described, and preliminary field data are reported. An integrated field experiment was designed to test individual SLB component tests related to erosion control, biobarriers, and subsurface capillary and migration barriers, and the progress made in emplacing the experiment is presented. Efforts to utilize the field data collected to validate hydrologic models (TRACR3D) important to waste management strategies are also presented. 11 references, 14 figures, 1 table

  1. Development of technology for the design of shallow land burial facilities at arid sites

    Nyhan, J.W.; Abeele, W.V.; Drennon, B.J.; Herrera, W.J.; Lopez, E.A.; Langhorst, G.J.; Stallings, E.A.; Walker, R.D.; Martinez, J.L.

    1985-01-01

    The Los Alamos field research program involving technology development for arid shallow land burial (SLB) sites is described. Field data are presented for an integrated field experiment, which was designed to test individual SLB component experiments related to erosion control, biobarriers, and subsurface capillary and migration barriers. Field tests of biointrusion barriers at waste disposal sites and in experimental plots are reported. The results of a joint DOE/NRC experiment to evaluate leaching and transport of sorbing (Cs, Sr, Li) and nonsorbing (I, Br) solutes in sandy silt backfill are presented for steady-state and unsteady-state flow conditions. A capillary barrier experiment performed in a large caisson (3-m diameter, 6.1 m deep) is described and a year's worth of field data is presented

  2. Plant-Microbe Interactions and Water Management in Arid and Saline Soils

    Daffonchio, Daniele; Hirt, Heribert; Berg, Gabriele

    2014-01-01

    Drought and salinity are major factors limiting agriculture in many regions in the world, and their importance is predicted to even increase in the near future in parallel with the ongoing global warming and climate changes. Soil and rhizosphere microbes are potential resources for counteracting such abiotic stresses in plants. The knowledge on the roles of root microorganisms in retaining soil humidity and promoting plant growth under such abiotic stresses is analyzed in this chapter. The importance of microbial diversity in the rhizosphere for alleviating drought and salinity effects on the plant physiology is discussed in the light of “Desert Farming”, the general crop management practice that is frequently used in arid regions. The plant growth promoting functional services exerted by microorganisms within the rhizosphere in arid soils are presented in relation to the plant response under water stress.

  3. Plant-Microbe Interactions and Water Management in Arid and Saline Soils

    Daffonchio, Daniele

    2014-12-05

    Drought and salinity are major factors limiting agriculture in many regions in the world, and their importance is predicted to even increase in the near future in parallel with the ongoing global warming and climate changes. Soil and rhizosphere microbes are potential resources for counteracting such abiotic stresses in plants. The knowledge on the roles of root microorganisms in retaining soil humidity and promoting plant growth under such abiotic stresses is analyzed in this chapter. The importance of microbial diversity in the rhizosphere for alleviating drought and salinity effects on the plant physiology is discussed in the light of “Desert Farming”, the general crop management practice that is frequently used in arid regions. The plant growth promoting functional services exerted by microorganisms within the rhizosphere in arid soils are presented in relation to the plant response under water stress.

  4. Land Cover Change in Northern Botswana: The Influence of Climate, Fire, and Elephants on Semi-Arid Savanna Woodlands

    John Tyler Fox

    2017-10-01

    (p = 0.009, adj. R2 = 0.50, with a 41% increase in average fire occurrence in years when rainfall exceeded long-term mean annual precipitation (MAP. Loss of woodland was significantly associated with fire in locations experiencing 15 or more ignitions during the period 2001–2013 (p = 0.024. Although elephant-mediated damage is often cited as a major cause of woodland degradation in northern Botswana, we observed little evidence of unsustainable pressure on woodlands from growing elephant populations. Our data indicate broad-scale LCC processes in semi-arid savannas in Southern Africa are strongly coupled to environmental and anthropogenic forcings. Increased seasonal variability is likely to have important effects on the distribution of savanna plant communities due to climate-fire feedbacks. Long-term monitoring of LCC in these ecosystems is essential to improving land use planning and management strategies that protect biodiversity, as well as traditional cultures and livelihoods under future climate change scenarios for Southern Africa.

  5. JOJOBA: an oil plant for arid or semi-arid regions

    Marull, J E

    1978-01-01

    Jojoba (Simmondsia chinesis) grows in regions with a rainfall of 250 to 450 mm, producing 4.5 kg seeds/tree after 36 months and attaining an average production of 13.8 kg seeds/tree when full grown. Productivity can be maintained for up to 100 years. Planting density is about 1600 plants/ha, at distances of 1.50 x 3.00 m. The seeds contain 50% edible oil, and the press-cake 35% proteins. The characteristics of the oil are listed.

  6. Jojoba, an oil plant for arid or semi-arid regions

    Marull, J E

    1978-01-01

    Jojoba (Simmondsia chinensis) grows in regions with a rainfall of 250-450 mm, producing 4.5 kg seeds/tree after 36 months and attaining an average production of 13.8 kg seeds/tree when full grown. Productivity can be maintained for up to 100 years. Planting density is about 1600 plants/ha, at distances of 1.50 x 3.00 m. The seeds contain 50% edible oil, and the press-cake 35% proteins. The characteristics of the oil are listed.

  7. Predictive models of threatened plant species distribution in the Iberian arid south-east

    Benito, Blas M.

    2013-01-01

    Poster on the distribution of three rare, endemic and endangered annual plants of arid zones in the south-eastern Iberian peninsula. Presented in the workshop "Predictive Modelling of Species Distribution: New Tools for the XXI Century (Baeza, Spain, november 2005).

  8. Assessment of Plant Functional Types in Tropical Arid and Semi-Arid Ecosystems of India Using Remote Sensing Data and GIS

    Sudhakar Reddy, C.; Krishna, P. Hari; Murthy, M. S. R.

    2011-09-01

    vegetation systems were studied along arid, semi-arid and sub-humid regions of Indian Desert and Aravallis of Rajasthan, India, with a distance of 600 km. The annual precipitation decreases from as high as 1600 mm in the south to 700 mm in the north-east and 100 mm in the west. The study is based on the integrated approach of remote sensing, GIS, and phytosociology. In the step 1, vegetation type map was prepared using multi-season IRS P6 LISS III data. Screening of plant traits was done based on field observations and literature. Phytosociological data pertains to 500 sample plots was used to identify plant functional traits of 900 species at morphological level. The vegetation classification scheme at regional level identified thorn forest, dry deciduous forest, broad leaved forest, woodland, shrubland and grasslands. Five plant traits selected in the study were significant for tropical environments. Attributes such as leaf size, leaf texture, spinescence, stem diameter and bark consistency were categorized systematically. Ordination analysis was carried out across the environmental gradient. Plant functional traits were measured on 20 individuals per species at each site. Environmental information was integrated to identify plant trait response. The spatial trends in PFTs were analysed and compared across the vegetation types, along the gradient of land surface temperature, climate, elevation and time integrated NDVI. Results established the occurrence of recurrent patterns of association among selected plant traits. Functional response groups were identified by summarizing results and relating them to individual species. Finally phytoclimatic map was prepared to represent spatial distribution of PFTs. The species with of functional traits of representing microphylls, sclerophyll, rough bark, spinescence and therophyte are demarcated as drought tolerant traits. Drought Intolerant PFTs are represented by macrophyll, malacophyll, smooth Bark, non spinescent stems and leaves

  9. Soil emissions of gaseous reactive nitrogen from North American arid lands: an overlooked source.

    Sparks, J. P.; McCalley, C. K.; Strahm, B. D.

    2008-12-01

    The biosphere-atmosphere exchange and transformation of nitrogen has important ramifications for both terrestrial biogeochemistry and atmospheric chemistry. Several important mechanisms within this process (e.g., photochemistry, nitrogen deposition, aerosol formation) are strongly influenced by the emission of reactive nitrogen compounds from the Earth's surface. Therefore, a quantification of emission sources is a high priority for future conceptual understanding. One source largely overlooked in most global treatments are the soil emissions from arid and semi-arid landscapes worldwide. Approximately 35-40% of global terrestrial land cover is aridland and emission of reactive nitrogen from soils in these regions has the potential to strongly influence both regional and global biogeochemistry. Here we present estimates of soil emission of oxidized (NO, total NOy including NO2 and HONO) and reduced (NH3) forms of reactive nitrogen from two North American arid regions: the Mojave Desert and the Colorado Plateau. Soil fluxes in these regions are highly dependent on soil moisture conditions. Soil moisture is largely driven by pulsed rain events with fluxes increasing 20-40 fold after a rain event. Using field measurements made across seasons under an array of moisture conditions, precipitation records, and spatially explicit cover type information we have estimated annual estimates for the Mojave Desert (1.5 ± 0.7 g N ha-1 yr-1), the shale derived (1.4 ± 0.9 g N ha-1 yr-1), and sandy soil derived (2.8 ± 1.2 g N ha-1 yr-1) regions of the Colorado Plateau. The chemical composition of soil emissions varies significantly both with season and soil moisture content. Emissions from dry soils tend to be dominated by ammonia and forms of NOy other than NO. In contrast, NO becomes a dominant portion of the flux post rain events (~30% of the total flux). This variability in chemical form has significant implications for the tropospheric fate of the emitted N. NO and other

  10. Transitions in Land Use Architecture under Multiple Human Driving Forces in a Semi-Arid Zone

    Issa Ouedraogo

    2015-07-01

    Full Text Available The present study aimed to detect the main shifts in land-use architecture and assess the factors behind the changes in typical tropical semi-arid land in Burkina Faso. Three sets of time-series LANDSAT data over a 23-year period were used to detect land use changes and their underpinning drivers in multifunctional but vulnerable ecologies. Group discussions in selected villages were organized for mapping output interpretation and collection of essential drivers of change as perceived by local populations. Results revealed profound changes and transitions during the study period. During the last decade, shrub and wood savannahs exhibited high net changes (39% and −37% respectively with a weak net positive change for cropland (only 2%, while cropland and shrub savannah exhibited high swap (8% and 16%. This suggests that the area of cropland remained almost unchanged but was subject to relocation, wood savannah decreased drastically, and shrub savannah increased exponentially. Cropland exhibited a null net persistence while shrub and wood savannahs exhibited positive and negative net persistence (1.91 and −10.24, respectively, indicating that there is movement toward agricultural intensification and wood savannah tended to disappear to the benefit of shrub savannah. Local people are aware of the changes that have occurred and support the idea that illegal wood cutting and farming are inappropriate farming practices associated with immigration; absence of alternative cash generation sources, overgrazing and increasing demand for wood energy are driving the changes in their ecosystems. Policies that integrate restoration and conservation of natural ecosystems and promote sustainable agroforestry practices in the study zone are highly recommended.

  11. On the sensitivity of Land Surface Temperature estimates in arid irrigated lands using MODTRAN

    Rosas, Jorge

    2015-11-29

    Land surface temperature (LST) derived from thermal infrared (TIR) satellite data has been reliably used as a remote indicator of evapotranspiration (ET) and surface moisture status. However, in order to retrieve the ET with an accuracy approaching 10%, LST should be retrieved to within 1 ◦C or better, disregarding other elements of uncertainty. The removal of atmospheric effects is key towards achieving a precise estimation of LST and it requires detailed information on water vapor. The Thermal Infrared Sensor (TIRS) onboard Landsat 8 captures data in two long wave thermal bands with 100-meter resolution. However, the US Geological Survey has reported a calibration problem of TIRS bands caused by stray light, resulting in a higher bias in one of its two bands (4% in band 11, 2% in band 10). Therefore, split-window algorithms for the estimation of LST might not be reliable. Our work will focus on the impact of using different atmospheric profiles (e.g. weather prediction models, satellite) for the estimation of LST derived from MODTRAN by using one of the TIRS bands onboard Landsat 8 (band 10). Sites with in-situ measurements of LST are used as evaluation sources. Comparisons between the measured LST and LST derived based on different atmospheric profile inputs to MODTRAN are carried out from 2 Landsat-overpass days (DOY 153 and 160 2015). Preliminary results show a mean absolute error of around 3 ◦C between in-situ and estimated LST over two different crops (alfalfa and carrot) and bare soil.

  12. Land degradation assessment by geo-spatially modeling different soil erodibility equations in a semi-arid catchment.

    Saygın, Selen Deviren; Basaran, Mustafa; Ozcan, Ali Ugur; Dolarslan, Melda; Timur, Ozgur Burhan; Yilman, F Ebru; Erpul, Gunay

    2011-09-01

    Land degradation by soil erosion is one of the most serious problems and environmental issues in many ecosystems of arid and semi-arid regions. Especially, the disturbed areas have greater soil detachability and transportability capacity. Evaluation of land degradation in terms of soil erodibility, by using geostatistical modeling, is vital to protect and reclaim susceptible areas. Soil erodibility, described as the ability of soils to resist erosion, can be measured either directly under natural or simulated rainfall conditions, or indirectly estimated by empirical regression models. This study compares three empirical equations used to determine the soil erodibility factor of revised universal soil loss equation prediction technology based on their geospatial performances in the semi-arid catchment of the Saraykoy II Irrigation Dam located in Cankiri, Turkey. A total of 311 geo-referenced soil samples were collected with irregular intervals from the top soil layer (0-10 cm). Geostatistical analysis was performed with the point values of each equation to determine its spatial pattern. Results showed that equations that used soil organic matter in combination with the soil particle size better agreed with the variations in land use and topography of the catchment than the one using only the particle size distribution. It is recommended that the equations which dynamically integrate soil intrinsic properties with land use, topography, and its influences on the local microclimates, could be successfully used to geospatially determine sites highly susceptible to water erosion, and therefore, to select the agricultural and bio-engineering control measures needed.

  13. Photodegradation processes in arid ecosystems: controlling factors and potential application in land restoration

    Muñoz-Rojas, Miriam; Luna-Ramos, Lourdes; Oyonarte, Cecilio; Sole Benet, Albert

    2017-04-01

    Water availability plays a fundamental part in controlling biotic processes in arid ecosystems. However, recent evidence suggests that other decisive drivers take part in these processes. Despite low annual rainfall and microbial activity, unexplained high rates of litter decomposition, net nitrogen mineralization, soil enzymatic activity and carbon turnover have been observed in arid ecosystems. These observations have been partly explained by photodegradation, a process that consists of the breakdown of organic matter via solar radiation (UV) and that can increase decomposition rates and lead to changes in the balance of carbon and nutrients between plants, soil and atmosphere. A complete understanding of these mechanisms and its drivers in arid ecosystems remains a critical challenge for the scientific community at the global level. In this research, we conducted a multi-site field experiment to test the effects of photodegradation on decomposition of organic amendments used in ecosystem restoration. The study was carried out during 12 months in two study areas: the Pilbara region in Western Australia (Southern Hemisphere) and the Cabo de Gata Nijar Natural Park, South Spain (Northern Hemisphere). In both sites, four treatments were applied in replicated plots (1x1 m, n=4) that included a control (C) with no soil amendment; organic amendment covering the soil surface (AS); organic amendment incorporated into the soil (AI); and a combination of both techniques, both covering the surface and incorporated into the soil (AS-AI). Different organic amendments (native mulch versus compost) and soil substrates were used at each site according to local practices, but in both sites these were applied to increase soil organic matter up to 2%. At the two locations, a radiometer and a logger with a soil temperature and soil moisture probe were installed to monitor UV radiation and soil conditions for the duration of the trial. Soil microbial activity, soil CO2 efflux, and

  14. Woody plants and land use

    Huxley, P.A.

    1982-01-01

    The importance of woody species in land use systems has recently gained international attention. In addition to the production of food and fuelwood, trees can maintain or improve the fertility status of the soil and conserve both soil and water. The use of multipurpose trees in land use system and the important role of trees in association with other crops is now recognized. The methods of scientifically studying such systems, and of manipulating them to improve their productivity or net utility have not been well developed. This introductory paper documents the role of woody species in agriculture, forestry and agroforestry. It outlines some of the important research needs for such systems and the role which isotopes could play in the research. (author)

  15. Evidence for micronutrient limitation of biological soil crusts: Importance to arid-lands restoration

    Bowker, M.A.; Belnap, J.; Davidson, D.W.; Phillips, S.L.

    2005-01-01

    Desertification is a global problem, costly to national economies and human societies. Restoration of biological soil crusts (BSCs) may have an important role to play in the reversal of desertification due to their ability to decrease erosion and enhance soil fertility. To determine if there is evidence that lower fertility may hinder BSC recolonization, we investigated the hypothesis that BSC abundance is driven by soil nutrient concentrations. At a regional scale (north and central Colorado Plateau, USA), moss and lichen cover and richness are correlated with a complex water-nutrient availability gradient and have approximately six-fold higher cover and approximately two-fold higher species richness on sandy soils than on shale-derived soils. At a microscale, mosses and lichens are overrepresented in microhabitats under the north sides of shrub canopies, where water and nutrients are more available. At two spatial scales, and at the individual species and community levels, our data are consistent with the hypothesis that distributions of BSC organisms are determined largely by soil fertility. The micronutrients Mn and Zn figured prominently and consistently in the various analyses, strongly suggesting that these elements are previously unstudied limiting factors in BSC development. Structural-equation modeling of our data is most consistent with the hypothesis of causal relationships between the availability of micronutrients and the abundance of the two major nitrogen (N) fixers of BSCs. Specifically, higher Mn availability may determine greater Collema tenax abundance, and both Mn and Zn may limit Collema coccophorum; alternative causal hypotheses were less consistent with the data. We propose experimental trials of micronutrient addition to promote the restoration of BSC function on disturbed lands. Arid lands, where BSCs are most prevalent, cover ???40% of the terrestrial surface of the earth; thus the information gathered in this study is potentially useful

  16. Monitoring arid-land groundwater abstraction through optimization of a land surface model with remote sensing-based evaporation

    Lopez Valencia, Oliver Miguel

    2018-02-01

    The increase in irrigated agriculture in Saudi Arabia is having a large impact on its limited groundwater resources. While large-scale water storage changes can be estimated using satellite data, monitoring groundwater abstraction rates is largely non-existent at either farm or regional level, so water management decisions remain ill-informed. Although determining water use from space at high spatiotemporal resolutions remains challenging, a number of approaches have shown promise, particularly in the retrieval of crop water use via evaporation. Apart from satellite-based estimates, land surface models offer a continuous spatial-temporal evolution of full land-atmosphere water and energy exchanges. In this study, we first examine recent trends in terrestrial water storage depletion within the Arabian Peninsula and explore its relation to increased agricultural activity in the region using satellite data. Next, we evaluate a number of large-scale remote sensing-based evaporation models, giving insight into the challenges of evaporation retrieval in arid environments. Finally, we present a novel method aimed to retrieve groundwater abstraction rates used in irrigated fields by constraining a land surface model with remote sensing-based evaporation observations. The approach is used to reproduce reported irrigation rates over 41 center-pivot irrigation fields presenting a range of crop dynamics over the course of one year. The results of this application are promising, with mean absolute errors below 3 mm:day-1, bias of -1.6 mm:day-1, and a first rough estimate of total annual abstractions of 65.8 Mm3 (close to the estimated value using reported farm data, 69.42 Mm3). However, further efforts to address the overestimation of bare soil evaporation in the model are required. The uneven coverage of satellite data within the study site allowed us to evaluate its impact on the optimization, with a better match between observed and obtained irrigation rates on fields with

  17. Corrective measures technology for shallow land burial at arid sites: field studies of biointrusion barriers and erosion control

    Nyhan, J.W.; Hakonson, T.E.; Lopez, E.A.

    1986-03-01

    The field research program involving corrective measures technologies for arid shallow land burial (SLB) sites is described. Results of field testing of a biointrusion barrier installed at a close-out waste disposal site (Area B) at Los Alamos are presented. Soil erosion and infiltration of water into a simulated trench cap with various surface treatments were measured, and the interaction between erosion control and subsurface water dynamics is discussed relative to waste management

  18. Changes in semi-arid plant species associations along a livestock grazing gradient.

    Hugo Saiz

    Full Text Available In semi-arid ecosystems, vegetation is heterogeneously distributed, with plant species often associating in patches. These associations between species are not constant, but depend on the particular response of each species to environmental factors. Here, we investigated how plant species associations change in response to livestock grazing in a semi-arid ecosystem, Cabo de Gata-Níjar Natural Park in South East Spain. We established linear point-intercept transects at four sites with different grazing intensity, and recorded all species at each point. We investigated plant associations by comparing the number of times that each pair of species occurred at the same spatial point (co-occurrences, with the expected number of times based on species abundances. We also assessed associations for each shrub and grass species by considering all their pairs of associations and for the whole plant community by considering all pairs of associations on each site. At all sites, the plant community had a negative pattern of association, with fewer co-occurrences than expected. Negative association in the plant community increased at maximum grazing intensity. Most species associated as expected, particularly grass species, and positive associations were most important at intermediate grazing intensities. No species changed its type of association along the grazing gradient. We conclude that in the present plant community, grazing-resistant species compete among themselves and segregate in space. Some shrub species act as refuges for grazing-sensitive species that benefit from being spatially associated with shrub species, particularly at intermediate grazing intensities where positive associations were highest. At high grazing intensity, these shrubs can no longer persist and positive associations decrease due to the disappearance of refuges. Spatial associations between plant species and their response to grazing help identify the factors that organize

  19. Functionally relevant climate variables for arid lands: Aclimatic water deficit approach for modelling desert shrub distributions

    Thomas E. Dilts; Peter J. Weisberg; Camie M. Dencker; Jeanne C. Chambers

    2015-01-01

    We have three goals. (1) To develop a suite of functionally relevant climate variables for modelling vegetation distribution on arid and semi-arid landscapes of the Great Basin, USA. (2) To compare the predictive power of vegetation distribution models based on mechanistically proximate factors (water deficit variables) and factors that are more mechanistically removed...

  20. Waste Isolation Pilot Plant, Land Management Plan

    1993-12-01

    To reflect the requirement of section 4 of the Wastes Isolation Pilot Plant Land Withdrawal Act (the Act) (Public Law 102-579), this land management plan has been written for the withdrawal area consistent with the Federal Land Policy and Management Act of 1976. The objective of this document, per the Act, is to describe the plan for the use of the withdrawn land until the end of the decommissioning phase. The plan identifies resource values within the withdrawal area and promotes the concept of multiple-use management. The plan also provides opportunity for participation in the land use planning process by the public and local, State, and Federal agencies. Chapter 1, Introduction, provides the reader with the purpose of this land management plan as well as an overview of the Waste Isolation Pilot Plant. Chapter 2, Affected Environment, is a brief description of the existing resources within the withdrawal area. Chapter 3, Management Objectives and Planned Actions, describes the land management objectives and actions taken to accomplish these objectives.

  1. Waste Isolation Pilot Plant, Land Management Plan

    1993-01-01

    To reflect the requirement of section 4 of the Wastes Isolation Pilot Plant Land Withdrawal Act (the Act) (Public Law 102-579), this land management plan has been written for the withdrawal area consistent with the Federal Land Policy and Management Act of 1976. The objective of this document, per the Act, is to describe the plan for the use of the withdrawn land until the end of the decommissioning phase. The plan identifies resource values within the withdrawal area and promotes the concept of multiple-use management. The plan also provides opportunity for participation in the land use planning process by the public and local, State, and Federal agencies. Chapter 1, Introduction, provides the reader with the purpose of this land management plan as well as an overview of the Waste Isolation Pilot Plant. Chapter 2, Affected Environment, is a brief description of the existing resources within the withdrawal area. Chapter 3, Management Objectives and Planned Actions, describes the land management objectives and actions taken to accomplish these objectives

  2. Land use reconversion in the drought-and aridity-affected areas in SW Romania (Bechet, Dolj County

    IULIANA VIJULIE

    2017-12-01

    Full Text Available In the terms of current climate change, reconversion of land use in the drought-and aridityaffected south-western Romania, is an issue of utmost priority. Thus, the present study aim represents a diachronic analysis of the land use within the Bechet town area and proposes viable solutions for soil drought and aridity mitigation. Since 1989, uncontrolled and abusive logging affected the black locust forest areas, enabling the sand dunes expansion and causing ecological disturbance. The main research methods were: field observation, statistical-mathematical methods and GIS mapping. The analysis of topographic maps and orthophotographs in 1970 to 2008 revealed a very low spatial distribution of both the forest shelterbelts and shelterwoods. We proposed a reconstruction of these forest areas, which today can no longer perform their fundamental function of land protection, because of intensive degradation. The positive consequences on long term would be the mitigation of climate change impact and prevention of further land degradation.

  3. Report on the lands of the arid region of the United States with a more detailed account of the land of Utah with maps

    Powell, John Wesley

    1879-01-01

    A report from Maj. J. W.Powell, geologist in charge of the United States Geographical and Geological Survey of the Rocky Mountain Region, upon the lands of the Arid Region of the United States, setting forth the extent of said region, and making suggestions as to the conditions under which the lands embraced within its limit may be rendered available for agricultural and grazing purposes. With the report is transmitted a statement of the rainfall of the western portion of the United States, with reports upon the subject of irrigation by Capt. C. E. Button, U. S. A., Prof. A. H. Thompson, and Mr. G. K. Gilbert.

  4. A DNA barcode for land plants.

    2009-08-04

    DNA barcoding involves sequencing a standard region of DNA as a tool for species identification. However, there has been no agreement on which region(s) should be used for barcoding land plants. To provide a community recommendation on a standard plant barcode, we have compared the performance of 7 leading candidate plastid DNA regions (atpF-atpH spacer, matK gene, rbcL gene, rpoB gene, rpoC1 gene, psbK-psbI spacer, and trnH-psbA spacer). Based on assessments of recoverability, sequence quality, and levels of species discrimination, we recommend the 2-locus combination of rbcL+matK as the plant barcode. This core 2-locus barcode will provide a universal framework for the routine use of DNA sequence data to identify specimens and contribute toward the discovery of overlooked species of land plants.

  5. A DNA barcode for land plants

    Hollingsworth, Peter M.; Forrest, Laura L.; Spouge, John L.; Hajibabaei, Mehrdad; Ratnasingham, Sujeevan; van der Bank, Michelle; Chase, Mark W.; Cowan, Robyn S.; Erickson, David L.; Fazekas, Aron J.; Graham, Sean W.; James, Karen E.; Kim, Ki-Joong; Kress, W. John; Schneider, Harald; van AlphenStahl, Jonathan; Barrett, Spencer C.H.; van den Berg, Cassio; Bogarin, Diego; Burgess, Kevin S.; Cameron, Kenneth M.; Carine, Mark; Chacón, Juliana; Clark, Alexandra; Clarkson, James J.; Conrad, Ferozah; Devey, Dion S.; Ford, Caroline S.; Hedderson, Terry A.J.; Hollingsworth, Michelle L.; Husband, Brian C.; Kelly, Laura J.; Kesanakurti, Prasad R.; Kim, Jung Sung; Kim, Young-Dong; Lahaye, Renaud; Lee, Hae-Lim; Long, David G.; Madriñán, Santiago; Maurin, Olivier; Meusnier, Isabelle; Newmaster, Steven G.; Park, Chong-Wook; Percy, Diana M.; Petersen, Gitte; Richardson, James E.; Salazar, Gerardo A.; Savolainen, Vincent; Seberg, Ole; Wilkinson, Michael J.; Yi, Dong-Keun; Little, Damon P.

    2009-01-01

    DNA barcoding involves sequencing a standard region of DNA as a tool for species identification. However, there has been no agreement on which region(s) should be used for barcoding land plants. To provide a community recommendation on a standard plant barcode, we have compared the performance of 7 leading candidate plastid DNA regions (atpF–atpH spacer, matK gene, rbcL gene, rpoB gene, rpoC1 gene, psbK–psbI spacer, and trnH–psbA spacer). Based on assessments of recoverability, sequence quality, and levels of species discrimination, we recommend the 2-locus combination of rbcL+matK as the plant barcode. This core 2-locus barcode will provide a universal framework for the routine use of DNA sequence data to identify specimens and contribute toward the discovery of overlooked species of land plants. PMID:19666622

  6. Land Cover Land Use change and soil organic carbon under climate variability in the semi-arid West African Sahel (1960-2050)

    Dieye, Amadou M.

    Land Cover Land Use (LCLU) change affects land surface processes recognized to influence climate change at local, national and global levels. Soil organic carbon is a key component for the functioning of agro-ecosystems and has a direct effect on the physical, chemical and biological characteristics of the soil. The capacity to model and project LCLU change is of considerable interest for mitigation and adaptation measures in response to climate change. A combination of remote sensing analyses, qualitative social survey techniques, and biogeochemical modeling was used to study the relationships between climate change, LCLU change and soil organic carbon in the semi-arid rural zone of Senegal between 1960 and 2050. For this purpose, four research hypotheses were addressed. This research aims to contribute to an understanding of future land cover land use change in the semi-arid West African Sahel with respect to climate variability and human activities. Its findings may provide insights to enable policy makers at local to national levels to formulate environmentally and economically adapted policy decisions. This dissertation research has to date resulted in two published and one submitted paper.

  7. Modeling Soil Moisture in Support of the Revegetation of Military Lands in Arid Regions.

    Caldwell, T. G.; McDonald, E. V.; Young, M. H.

    2003-12-01

    The National Training Center (NTC), the Army's primary mechanized maneuver training facility, covers approximately 2600 km2 within the Mojave Desert in southern California, and is the subject of ongoing studies to support the sustainability of military lands in desert environments. Revegetation of these lands by the Integrated Training Areas Management (ITAM) Program requires the identification of optimum growing conditions to reestablish desert vegetation from seed and seedling, especially with regard to the timing and abundance of plant-available water. Water content, soil water potential, and soil temperature were continuously monitored and used to calibrate the Simultaneous Heat And Water (SHAW) model at 3 re-seeded sites. Modeled irrigation scenarios were used to further evaluate the most effective volume, frequency, and timing of irrigation required to maximize revegetation success and minimize water use. Surface treatments including straw mulch, gravel mulch, soil tackifier and plastic sheet

  8. Habitat fragmentation in arid zones: a case study of Linaria nigricans under land use changes (SE Spain).

    Peñas, Julio; Benito, Blas; Lorite, Juan; Ballesteros, Miguel; Cañadas, Eva María; Martinez-Ortega, Montserrat

    2011-07-01

    Habitat fragmentation due to human activities is one of the most important causes of biodiversity loss. In Mediterranean areas the species have co-evolved with traditional farming, which has recently been replaced for more severe and aggressive practices. We use a methodological approach that enables the evaluation of the impact that agriculture and land use changes have for the conservation of sensitive species. As model species, we selected Linaria nigricans, a critically endangered plant from arid and semiarid ecosystems in south-eastern Spain. A chronosequence of the evolution of the suitable habitat for the species over more than 50 years has been reconstructed and several geometrical fragmentation indices have been calculated. A new index called fragmentation cadence (FC) is proposed to quantify the historical evolution of habitat fragmentation regardless of the habitat size. The application of this index has provided objective forecasting of the changes of each remnant population of L. nigricans. The results indicate that greenhouses and construction activities (mainly for tourist purposes) exert a strong impact on the populations of this endangered species. The habitat depletion showed peaks that constitute the destruction of 85% of the initial area in only 20 years for some populations of L. nigricans. According to the forecast established by the model, a rapid extinction could take place and some populations may disappear as early as the year 2030. Fragmentation-cadence analysis can help identify population units of primary concern for its conservation, by means of the adoption of improved management and regulatory measures.

  9. UAV hyperspectral and lidar data and their fusion for arid and semi-arid land vegetation monitoring

    We demonstrate a unique fusion of unmanned aerial vehicle (UAV) lidar and hyperspectral imagery for individual plant species identification and 3D characterization of the earth surface at sub-meter scales in southeastern Arizona, USA. We hypothesized that the fusion of the two different data sources...

  10. In vitro antagonistic activity, plant growth promoting traits and phylogenetic affiliation of rhizobacteria associated with wild plants grown in arid soil

    El-Sayed, Wael S.; Akhkha, Abdellah; El-Naggar, Moustafa Y.; Elbadry, Medhat

    2014-01-01

    The role of plant growth-promoting rhizobacteria (PGPR) in adaptation of plants in extreme environments is not yet completely understood. For this study native bacteria were isolated from rhizospeheric arid soils and evaluated for both growth-promoting abilities and antagonistic potential against phytopathogenic fungi and nematodes. The phylogentic affiliation of these representative isolates was also characterized. Rhizobacteria associated with 11 wild plant species from the arid soil of Alm...

  11. Multigene phylogeny of land plants with special reference to bryophytes and the earliest land plants.

    Nickrent, D L; Parkinson, C L; Palmer, J D; Duff, R J

    2000-12-01

    A widely held view of land plant relationships places liverworts as the first branch of the land plant tree, whereas some molecular analyses and a cladistic study of morphological characters indicate that hornworts are the earliest land plants. To help resolve this conflict, we used parsimony and likelihood methods to analyze a 6, 095-character data set composed of four genes (chloroplast rbcL and small-subunit rDNA from all three plant genomes) from all major land plant lineages. In all analyses, significant support was obtained for the monophyly of vascular plants, lycophytes, ferns (including PSILOTUM: and EQUISETUM:), seed plants, and angiosperms. Relationships among the three bryophyte lineages were unresolved in parsimony analyses in which all positions were included and weighted equally. However, in parsimony and likelihood analyses in which rbcL third-codon-position transitions were either excluded or downweighted (due to apparent saturation), hornworts were placed as sister to all other land plants, with mosses and liverworts jointly forming the second deepest lineage. Decay analyses and Kishino-Hasegawa tests of the third-position-excluded data set showed significant support for the hornwort-basal topology over several alternative topologies, including the commonly cited liverwort-basal topology. Among the four genes used, mitochondrial small-subunit rDNA showed the lowest homoplasy and alone recovered essentially the same topology as the multigene tree. This molecular phylogeny presents new opportunities to assess paleontological evidence and morphological innovations that occurred during the early evolution of terrestrial plants.

  12. LAND USE/LAND COVER CHANGES IN SEMI-ARID MOUNTAIN LANDSCAPE IN SOUTHERN INDIA: A GEOINFORMATICS BASED MARKOV CHAIN APPROACH

    S. A. Rahaman

    2017-05-01

    Full Text Available Nowadays land use/ land cover in mountain landscape is in critical condition; it leads to high risky and uncertain environments. These areas are facing multiple stresses including degradation of land resources; vagaries of climate and depletion of water resources continuously affect land use practices and livelihoods. To understand the Land use/Land cover (Lu/Lc changes in a semi-arid mountain landscape, Kallar watershed of Bhavani basin, in southern India has been chosen. Most of the hilly part in the study area covers with forest, plantation, orchards and vegetables and which are highly affected by severe soil erosion, landslide, frequent rainfall failures and associated drought. The foothill regions are mainly utilized for agriculture practices; due to water scarcity and meagre income, the productive agriculture lands are converted into settlement plots and wasteland. Hence, land use/land cover change deduction; a stochastic processed based method is indispensable for future prediction. For identification of land use/land cover, and vegetation changes, Landsat TM, ETM (1995, 2005 and IRS P6- LISS IV (2015 images were used. Through CAMarkov chain analysis, Lu/Lc changes in past three decades (1995, 2005, and 2015 were identified and projected for (2020 and 2025; Normalized Difference Vegetation Index (NDVI were used to find the vegetation changes. The result shows that, maximum changes occur in the plantation and slight changes found in forest cover in the hilly terrain. In foothill areas, agriculture lands were decreased while wastelands and settlement plots were increased. The outcome of the results helps to farmer and policy makers to draw optimal lands use planning and better management strategies for sustainable development of natural resources.

  13. Land Use/land Cover Changes in Semi-Arid Mountain Landscape in Southern India: a Geoinformatics Based Markov Chain Approach

    Rahaman, S. A.; Aruchamy, S.; Balasubramani, K.; Jegankumar, R.

    2017-05-01

    Nowadays land use/ land cover in mountain landscape is in critical condition; it leads to high risky and uncertain environments. These areas are facing multiple stresses including degradation of land resources; vagaries of climate and depletion of water resources continuously affect land use practices and livelihoods. To understand the Land use/Land cover (Lu/Lc) changes in a semi-arid mountain landscape, Kallar watershed of Bhavani basin, in southern India has been chosen. Most of the hilly part in the study area covers with forest, plantation, orchards and vegetables and which are highly affected by severe soil erosion, landslide, frequent rainfall failures and associated drought. The foothill regions are mainly utilized for agriculture practices; due to water scarcity and meagre income, the productive agriculture lands are converted into settlement plots and wasteland. Hence, land use/land cover change deduction; a stochastic processed based method is indispensable for future prediction. For identification of land use/land cover, and vegetation changes, Landsat TM, ETM (1995, 2005) and IRS P6- LISS IV (2015) images were used. Through CAMarkov chain analysis, Lu/Lc changes in past three decades (1995, 2005, and 2015) were identified and projected for (2020 and 2025); Normalized Difference Vegetation Index (NDVI) were used to find the vegetation changes. The result shows that, maximum changes occur in the plantation and slight changes found in forest cover in the hilly terrain. In foothill areas, agriculture lands were decreased while wastelands and settlement plots were increased. The outcome of the results helps to farmer and policy makers to draw optimal lands use planning and better management strategies for sustainable development of natural resources.

  14. Developing User-Driven Climate Information Services to Build Resilience Amongst Groups at Risk of Drought and Flood in Arid and Semi-Arid Land Counties in Kenya

    Githungo, W. N.; Shaka, A.; Kniveton, D.; Muithya, L.; Powell, R.; Visman, E. L.

    2014-12-01

    The Arid and Semi-Arid Land (ASAL) counties of Kitui and Makueni in Kenya are experiencing increasing climate variability in seasonal rainfall, including changes in the onset, cessation and distribution of the two principal rains upon which the majority of the population's small-holder farmers and livestock keepers depend. Food insecurity is prevalent with significant numbers also affected by flooding during periods of intense rainfall. As part of a multi-partner Adaptation Consortium, Kenya Meteorological Services (KMS) are developing Climate Information Services (CIS) which can better support decision making amongst the counties' principal livelihoods groups and across County Government ministries. Building on earlier pilots and stakeholder discussion, the system combines the production of climate information tailored for transmission via regional and local radio stations with the establishment of a new SMS service. SMS are provided through a network of CIS intermediaries drawn from across key government ministries, religious networks, non-governmental and community groups, aiming to achieve one SMS recipient per 3-500 people. It also introduces a demand-led, premium-rate SMS weather information service which is designed to be self-financing in the long term. Supporting the ongoing process of devolution, KMS is downscaling national forecasts for each county, and providing seasonal, monthly, weekly and daily forecasts, as well as warnings of weather-related hazards. Through collaboration with relevant ministries, government bodies and research institutions, including livestock, agriculture, drought management and health, technical advisories are developed to provide guidance on application of the climate information. The system seeks to provide timely, relevant information which can enable people to use weather and climate information to support decisions which protect life and property and build resilience to ongoing climate variability and future change.

  15. On the operationalization of a spatially explicit evaluation of the complexity of land use trajectories in semi-arid Mediterranean agro-ecosystems

    Nainggolan, Doan

    This thesis aims to unpack the complexity of trajectories of land use change in semi-arid Mediterranean agro-ecosystems – illustrated using findings from the Torrealvilla catchment in south-eastern Spain. The research looks at multiple dimensions of land use change and addresses the past, present...

  16. Preliminary criteria for shallow-land storage/disposal of low-level radioactive solid waste in an arid environment

    Shord, A.L.

    1979-09-01

    Preliminary criteria for shallow land storage/disposal of low level radioactive solid waste in an arid environment were developed. Criteria which address the establishment and operation of a storage/disposal facility for low-level radioactive solid wastes are discussed. These were developed from the following sources: (1) a literature review of solid waste burial; (2) a review of the regulations, standards, and codes pertinent to the burial of radioactive wastes; (3) on site experience; and (4) evaluation of existing burial grounds and practices

  17. Hydrological response to land cover changes and human activities in arid regions using a geographic information system and remote sensing.

    Shereif H Mahmoud

    Full Text Available The hydrological response to land cover changes induced by human activities in arid regions has attracted increased research interest in recent decades. The study reported herein assessed the spatial and quantitative changes in surface runoff resulting from land cover change in the Al-Baha region of Saudi Arabia between 1990 and 2000 using an ArcGIS-surface runoff model and predicted land cover and surface runoff depth in 2030 using Markov chain analysis. Land cover maps for 1990 and 2000 were derived from satellite images using ArcGIS 10.1. The findings reveal a 26% decrease in forest and shrubland area, 28% increase in irrigated cropland, 1.5% increase in sparsely vegetated land and 0.5% increase in bare soil between 1990 and 2000. Overall, land cover changes resulted in a significant decrease in runoff depth values in most of the region. The decrease in surface runoff depth ranged from 25-106 mm/year in a 7020-km2 area, whereas the increase in such depth reached only 10 mm/year in a 243-km2 area. A maximum increase of 73 mm/year was seen in a limited area. The surface runoff depth decreased to the greatest extent in the central region of the study area due to the huge transition in land cover classes associated with the construction of 25 rainwater harvesting dams. The land cover prediction revealed a greater than twofold increase in irrigated cropland during the 2000-2030 period, whereas forest and shrubland are anticipated to occupy just 225 km2 of land area by 2030, a significant decrease from the 747 km2 they occupied in 2000. Overall, changes in land cover are predicted to result in an annual increase in irrigated cropland and dramatic decline in forest area in the study area over the next few decades. The increase in surface runoff depth is likely to have significant implications for irrigation activities.

  18. EVALUATION OF HYBRIDS FROM SIMPLE CROSSES USING MAIZE ELITE LANDRACES WITH FORAGE OUTSTANDING CHARACTERISTICS FOR A MEXICAN ARID LAND

    José L. García Hernández

    2013-04-01

    Full Text Available The Comarca Lagunera region is the most important area of maize forage in México. In this region; which is shared by the Mexican States of Coahuila and Durango, are used a great amount of hybrids and varieties of maize imported from other countries. Generally, these genotypes are not completely adapted to the soil and/or climatic conditions of the region. These antecedents lead scientists to pursuit for genotypes with the best adaptation to such conditions. The present investigation was carried out with the aim to find the best hybrids from the crosses of ten self-pollinating landraces following a diallel mating design. The landraces were obtained from different institutions: a the International Maize and Wheat Improvement Center (CIMMYT, b the “Antonio Narro” Agrarian Autonomist University (UAAAN, and c the National Institute of Agriculture, Forestry and Livestock Research (INIFAP. The following variables were evaluated from the hybrids: whole plant fresh matter yield (FMY, whole plant dry matter (DMY, fresh fruit yield (FFY fresh stem yield (FSY, and fresh foliar yield (FLY. All variables reported as t ha-1. The Griffing statistical analysis was used to determine the general combining ability (GCA, and the specific combining ability (SCA. The highest values of GCA were obtained for the landraces M7, M8, and M9. The hybrids with highest SCA were: M5xM7, M2xM7, M6x10, M4xM8, M5xM8, M8xM10, M2xM5, M1xM10 and M6xM9. Two of these hybrids (M5xM7 and M2xM7 also showed the highest values for FMY and DMY. In conclusion, there is enough variability on FMY and DMY to believe on the possibility to find the most appropriate hybrid for the targeted region, and also to extend the breeding program to other arid lands in México

  19. Land burial facility at the Forsmark plant

    Bergman, C.; Ericsson, G.; Haegg, C.

    1987-01-01

    The report presents the formal background for the handling of the application for permission to build a plant for deposition of radioactive waste on land. The SSI (National Swedish Institute of Radiation Protection), basis for assessment are reported and relevant factors are presented. The radiation doses calculated by the SSI do not exceed a few stray microsievert per annum in spite of very pessimistical assumptions. The report constitutes assessment material for the standpoint to be taken by the SSI board. (L.F.)

  20. Symbiotic fungal associations in 'lower' land plants.

    Read, D J; Ducket, J G; Francis, R; Ligron, R; Russell, A

    2000-06-29

    An analysis of the current state of knowledge of symbiotic fungal associations in 'lower' plants is provided. Three fungal phyla, the Zygomycota, Ascomycota and Basidiomycota, are involved in forming these associations, each producing a distinctive suite of structural features in well-defined groups of 'lower' plants. Among the 'lower' plants only mosses and Equisetum appear to lack one or other of these types of association. The salient features of the symbioses produced by each fungal group are described and the relationships between these associations and those formed by the same or related fungi in 'higher' plants are discussed. Particular consideration is given to the question of the extent to which root fungus associations in 'lower' plants are analogous to 'mycorrhizas' of 'higher' plants and the need for analysis of the functional attributes of these symbioses is stressed. Zygomycetous fungi colonize a wide range of extant lower land plants (hornworts, many hepatics, lycopods, Ophioglossales, Psilotales and Gleicheniaceae), where they often produce structures analogous to those seen in the vesicular-arbuscular (VA) mycorrhizas of higher plants, which are formed by members of the order Glomales. A preponderance of associations of this kind is in accordance with palaeohbotanical and molecular evidence indicating that glomalean fungi produced the archetypal symbioses with the first plants to emerge on to land. It is shown, probably for the first time, that glomalean fungi forming typical VA mycorrhiza with a higher plant (Plantago lanceolata) can colonize a thalloid liverwort (Pellia epiphylla), producing arbuscules and vesicles in the hepatic. The extent to which these associations, which are structurally analogous to mycorrhizas, have similar functions remains to be evaluated. Ascomycetous associations are found in a relatively small number of families of leafy liverworts. The structural features of the fungal colonization of rhizoids and underground axes of

  1. Influence of Acacia trees on soil nutrient levels in arid lands

    De Boever, Maarten; Gabriels, Donald; Ouessar, Mohamed; Cornelis, Wim

    2014-05-01

    The potential of scattered trees as keystone structures in restoring degraded environments is gaining importance. Scattered trees have strong influence on their abiotic environment, mainly causing changes in microclimate, water budget and soil properties. They often function as 'nursing trees', facilitating the recruitment of other plants. Acacia raddiana is such a keystone species which persists on the edge of the Sahara desert. The study was conducted in a forest-steppe ecosystem in central Tunisia where several reforestation campaigns with Acacia took place. To indentify the impact of those trees on soil nutrients, changes in nutrient levels under scattered trees of three age stages were examined for the upper soil layer (0-10 cm) at five microsites with increasing distance from the trunk. In addition, changes in soil nutrient levels with depth underneath and outside the canopy were determined for the 0-30 cm soil layer. Higher concentrations of organic matter (OM) were found along the gradient from underneath to outside the canopy for large trees compared to medium and small trees, especially at microsites close to the trunk. Levels of soluble K, electrical conductivity (EC), available P, OM, total C and N decreased whereas pH and levels of soluble Mg increased with increasing distance from tree. Levels of soluble Ca and Na remained unchanged along the gradient. At the microsite closest to the trunk a significant decrease in levels of soluble K, EC, OM, available P, total C and N, while a significant increase in pH was found with increasing depth. The concentration of other nutrients remained unchanged or declined not differently underneath compared to outside the canopy with increasing depth. Differences in nutrient levels were largely driven by greater inputs of organic matter under trees. Hence, Acacia trees can affect the productivity and reproduction of understory species with the latter in term an important source of organic matter. This positive feedback

  2. Draft interim close-out report Fitzner-Eberhardt Arid Lands Ecology Reserve remedial action, Hanford, Washington. Draft A

    1994-10-01

    The Fitzner-Eberhardt Arid Lands Ecology (ALE) Reserve consists of 120 square miles of shrub-steppe land on the western edge of the Hanford Site. It is located south of Highway 240 and east of the point where the Yakima River borders the site. The land was set aside as a natural research area in 1967 by the Atomic Energy Commission. With the recent change in mission at Hanford from plutonium production to environmental cleanup, much attention has been given to releasing clean tracts of land for other uses. The ALE Reserve is one such tract of land. Consistent with the Record of Decision (ROD) and Preliminary Assessment Screening (PAS), sites identified as having the potential for contamination on the ALE Reserve have been investigated, characterized, and remediated where necessary to comply with MTCA cleanup levels. Hazardous substances released to the environment have either been removed from the site or, in one case when removal was not practical, capped in place. Removal of all of the contaminated soil is supported by the confirmatory sampling results. The existing areas of contamination in the ALE Reserve were considered to be small. In March of 1993, Department of Energy (DOE), the Environmental Protection Agency and the Washington State Department of Ecology signed an Agreement in Principle in which they agreed to expedite cleanup of the ALE Reserve. Cleanup activities and a draft closeout report were to be completed by October 1994. Additionally, DOE proposed to mitigate hazards which may pose a physical threat to wildlife or humans

  3. Water, land, climate change and agrarian livelihood in an arid region riparian corridor: Rayón, Sonora, Mexico

    Lee, R.; Scott, C. A.; Curl, K.; House-Peters, L.; Buechler, S.

    2012-12-01

    Results of recent fieldwork in Rayón, Sonora, Mexico (funded by NSF's "Strengthening Resilience of Arid Region Riparian Corridors") indicate that the coupled natural and human (CNH) system that has persisted since the town's founding in 1626 is being degraded and destabilised by a confluence of social and ecological pressures. System change or loss of key system services and products has important implications for ecological services and human economic activity in the riparian corridor. Less water quantity is the primary factor responsible for driving system degradation and change. Drought caused by climate change is widely perceived by agriculturists as responsible for reduced water quantity in the riparian area. Reductions in water quantity are so severe that the once perennial Rio San Miguel did not run during 2012's summer months for the first time in residents' memory. Ninety-percent of wells are dry. Fields irrigated by surface-water acequias were not planted. Starvation or dehydration has thinned herd sizes. Residents fear they will lose the ability to practice their traditional livelihoods: ranching, farming and cheese production. Drought conditions and resource management in response to climatic change have had a net negative impact on ecological services. Agriculturists have responded to less forage and pasture for cattle by clearing mesquite forests, putting land into production, and increasing water demand. From interviews it appears this process is cyclical: agriculturists widely believe access to more water or an end to the drought are the only ways to improve conditions. Interviews also reveal (a) agriculturists view technology, especially that which is able to improve water-use efficiency, as means to reduce stress in the CNH system and (b) a holistic view that couples natural well-being to human well-being is absent from the majority of respondents' worldviews. Technological and adoption of holistic perceptions are adaptations that may potentially

  4. Soil, plant, and structural considerations for surface barriers in arid environments: Application of results from studies in the Mojave Desert near Beatty, Nevada

    Andraski, Brian J.; Prudic, David E.; ,

    1997-01-01

    The suitability of a waste-burial site depends on hydrologic processes that can affect the near-surface water balance. In addition, the loss of burial trench integrity by erosion and subsidence of trench covers may increase the likelihood of infiltration and percolation, thereby reducing the effectiveness of the site in isolating waste. Although the main components of the water balance may be defined, direct measurements can be difficult, and actual data for specific locations are seldom available. A prevalent assumption is that little or no precipitation will percolate to buried wastes at an arid site. Thick unsaturated zones, which are common to arid regions, are thought to slow water movement and minimize the risk of waste migration to the underlying water table. Thus, reliance is commonly placed on the natural system to isolate contaminants at waste-burial sites in the arid West.Few data are available to test assumptions about the natural soil-water flow systems at arid sites, and even less is known about how the natural processes are altered by construction of a waste-burial facility. The lack of data is the result of technical complexity of hydraulic characterization of the dry, stony soils, and insufficient field studies that account for the extreme temporal and spatial variations in precipitation, soils, and plants in arid regions. In 1976, the U.S. Geological Survey (USGS) began a long-term study at a waste site in the Mojave Desert. This paper summarizes the findings of ongoing investigations done under natural-site and waste-burial conditions, and discusses how this information may be applied to the design of surface barriers for waste sites in arid environments.The waste-burial site is in one of the most arid parts of the United States and is about 40 km northeast of Death Valley, near Beatty, Nev. (Figure 1). Precipitation averaged 108 mm/yr during 1981-1992. The water table is 85-115 m below land surface (Fischer, 1992). Sediments are largely alluvial

  5. Response of three semi-arid plant species to fluoride; consequences for chlorophyll florescence.

    Baunthiyal, M; Sharma, V

    2014-01-01

    The study was done to investigate the ability of three semi-arid plant species viz. Acacia tortilis, Cassia fistula and Prosopis juliflora to adapt to fluoride (F) stress. Here we examined the changes in activities of chlorophyll a fluorescence and photosynthetic pigment concentration during early growth of these plants. One month old plants were treated with 10, 20, and 50 mg kg(-1) F in soilrite. We did not observe any major change in photosynthetic performance of these plants during early growth. This was revealed by ETR, ETRmax, PPFD-sat and deltaF/Fm'-sat values which were higher in these plants. The decrease in chl a, chl b and total chl concentrations were significant only at 5 days. For most of the parameters, C. fistula was found to be more sensitive to F stress and P. juliflora showed least damage from F. The lesser inhibition in the parameters reflected the F tolerant nature of these plants with respect to photosynthesis. This opens the possibility of potential use of these species for treatment of F contaminated soil and water.

  6. Forests and water - Friends or foes?. Hydrological implications of deforestation and land degradation in semi-arid Tanzania

    Sandstroem, K.

    1995-01-01

    In the study area in Babati District in Tanzania a multi-component research approach was attempted. Two catchments, one forested and one deforested-degraded, were studied regarding soil properties, runoff and groundwater recharge. This was done both in the field and with the use of two computer models: one simulating groundwater recharge as a function of rainfall variability, and one simulating hydrological implications of massive land cover conversion on the flooding of nearby Lake Babati. Three major findings came out of the study. The first is that most forested catchments (in various hydroclimates and landscapes) will increase the runoff following deforestation (due to less evapotranspiration). This is well-established knowledge, but it also depends on the actual conditions at hand. These conditions are defined as hydroclimate, soil texture and slope. In humid-temperate climates with coarse soils on flat land, the conditions strongly favor increased runoff following deforestation. However, in dry regions with fine textured soils on hilly ground, and where deforestation also implies land degradation, less dry season flow is likely to develop after a considerable adjustment period has been allowed. Secondly, the prevalence of preferential flow in a forest soil, as compared to a compacted and eroded soil, must be a key component in an explanation of why more dry season flow can emerge from a forested as compared to a deforested catchment in the dry tropics. Thirdly, there are several aspects of semi-arid and arid tropical hydrology which make comparisons with humid-temperate regions difficult and require special attention in the management of water resources in the dry tropics. 14 refs, 18 figs, 1 tab

  7. Revegetation Plan for Areas of the Fitzner-Eberhardt Arid Lands Ecology Reserve Affected by Decommissioning of Buildings and Infrastructure and Debris Clean-up Actions

    Downs, Janelle L.; Durham, Robin E.; Larson, Kyle B.

    2011-01-01

    The U.S. Department of Energy (DOE), Richland Operations Office is working to remove a number of facilities on the Fitzner Eberhardt Arid Lands Ecology Reserve (ALE), which is part of the Hanford Reach National Monument. Decommissioning and removal of buildings and debris on ALE will leave bare soils and excavated areas that need to be revegetated to prevent erosion and weed invasion. Four main areas within ALE are affected by these activities (DOE 2009;DOE/EA-1660F): 1) facilities along the ridgeline of Rattlesnake Mountain, 2) the former Nike missile base and ALE HQ laboratory buildings, 3) the aquatic research laboratory at Rattlesnake Springs area, and 4) a number of small sites across ALE where various types of debris remain from previous uses. This revegetation plan addresses the revegetation and restoration of those land areas disturbed by decommissioning and removal of buildings, facilities and associated infrastructure or debris removal. The primary objective of the revegetation efforts on ALE is to establish native vegetation at each of the sites that will enhance and accelerate the recovery of the native plant community that naturally persists at that location. Revegetation is intended to meet the direction specified by the Environmental Assessment (DOE 2009; DOE/EA-1660F) and by Stipulation C.7 of the Memorandum of Agreement (MOA) for the Rattlesnake Mountain Combined Community Communication Facility and InfrastructureCleanup on the Fitzner/Eberhardt Arid Lands Ecology Reserve, Hanford Site, Richland Washington(DOE 2009; Appendix B). Pacific Northwest National Laboratory (PNNL) under contract with CH2M Hill Plateau Remediation Company (CPRC) and in consultation with the tribes and DOE-RL developed a site-specific strategy for each of the revegetation units identified within this document. The strategy and implementation approach for each revegetation unit identifies an appropriate native species mix and outlines the necessary site preparation activities

  8. Competition for pulsed resources: an experimental study of establishment and coexistence for an arid-land grass.

    Jankju-Borzelabad, Mohammad; Griffiths, Howard

    2006-07-01

    In arid environments, episodically-pulsed resources are important components of annual water and nutrient supply for plants. This study set out to test whether seedlings have an increased capacity for using pulsed resources, which might then improve establishment when in competition with older individuals. A second aim was to determine whether there is a trade-off in competitive strategies when resources are supplied continuously at low concentrations, or as pulses with pronounced inter-pulse periods. A glasshouse experiment used a target-neighbour design of size-asymmetric competition, with juveniles of Panicum antidotale (blue panicgrass) introduced into contrasting densities of adult plants. Stable isotopes of nitrogen were used for measuring plant resource uptake from pulses, and tolerance to inter-pulse conditions was assessed as the mean residence time (MRT) of nitrogen. A higher root/shoot ratio and finer root system enhanced the capacity of juveniles to use resources when pulsed, rather than when continuously supplied. Higher resource uptake during pulses improved the establishment of juvenile Panicum in mixed cultures with older individuals. However, a trade-off was observed in plant strategies, with juveniles showing a lower MRT for nitrogen, which suggested reduced tolerance to resource deficit during inter-pulse periods. Under field conditions, higher utilization of pulsed resources would lead to the improved seedling establishment of Panicum adjacent to "nurse" plants, whereas mature plants with well-developed roots, exploiting a greater soil volume, maintain more constant resource uptake and retention during inter-pulse periods.

  9. Should we plant trees to offset greenhouse gas emissions in semi-arid environments?

    Pataki, D. E.; Pincetl, S.; Gillespie, T. W.; Li, W.; McCarthy, H. R.; Saatchi, S.; Saphores, J.

    2008-12-01

    Urban tree planting programs have been gaining popularity in the United States. Urban trees have been associated with a variety of environmental benefits, including improvements in air quality, mitigation of urban heat island effects, reductions in stormwater runoff, and more recently, carbon sequestration. There are also other potential aesthetic and economic benefits of urban forests, which have been shown to affect real estate values. However, there may also be significant economic and environmental costs of planting and maintaining trees in urban areas, particularly in semi-arid environments where trees are not native and require irrigation and fertilization. We are conducting an analysis of the Million Tree Initiative in the city of Los Angeles, which has committed to a major tree planting program. Los Angeles currently has a low tree canopy cover relative to other cities, particularly in its low income neighborhoods. We are evaluating the decision-making processes associated with the new tree planting program, its perceived benefits, and its actual benefits based on measurements of plant and ecosystem processes such as transpiration, photosynthesis, and water use efficiency; remote sensing analyses of tree cover and surface temperature; and economic analyses. We have found great variability in the interpretation of the program by its various participants, but also significant institutional learning as the program has evolved. Our datasets have challenged some of the common assumptions of the program, for example, the assumption that native species use less water than imported species and are therefore more environmentally beneficial in terms of water resources. We have also found significant impacts of the urban forest on air temperature, which may reduce energy use during the summer due to reductions in air conditioning. This is likely to be a larger effect of urban trees on greenhouse gas emissions than direct carbon sequestration alone, which is a very

  10. Simulating the hydrologic impacts of land cover and climate changes in a semi-arid watershed

    U.S. Environmental Protection Agency — Changes in climate and land cover are among the principal variables affecting watershed hydrology. This paper uses a cell-based model to examine the hydrologic...

  11. A GIS-based integrative approach for land use optimization in a semi-arid watershed

    S.M. Tajbakhsh

    2018-01-01

    Full Text Available The proper use of natural resources can preserve these valuable assets. In line with the management of natural resources, land use optimization can be highly useful. The aim of the present study is to propose an appropriate integrative model for optimized allocation of lands for surface runoff and sediment load minimization and net income maximization in Bayg watershed, Iran. In this study, five categories of land uses, i.e. irrigated orchard, rangeland, irrigated farming, rainfed farming and almond orchard were spatially optimized to minimize surface runoff and sediment yield and to increase net income by integrating three approaches: weighted goal programming, analytic hierarchy process and multi-objective land allocation algorithm. To achieve the target levels in this work, the acreages of almond orchard and rainfed farming should be reduced by 100% and 37.32% respectively, and irrigated farming acreage should be increased by 138.53%. Through these alterations in the land use acreage, the sediment load will be reduced by 16.78% and net income will be improved by 72.52%. However, runoff volume will be increased by 0.22%. Results indicated that weighted goal programming satisfied 96% and 46% of the target levels of sediment load and net income respectively, but failed to reduce runoff volume. Therefore, it is necessary for managers to control runoff using the strategies related to runoff harvesting, especially on steep slopes. Generally, it can be concluded that a combination of the techniques weighted goal programming, analytic hierarchy process and multi-objective land allocation is highly capable to optimize land use and land covers based on the conflicting objectives.

  12. Fuel reprocessing plant environmental impact in the arid regions of the western United States. Annual report, October 1976--September 1977

    Seale, R.L.

    1977-01-01

    The first year of the fuel reprocessing plant environmental impact study has been completed. During this time, emphasis has been placed on the description of a reference plant and on the characterization of arid lands located sites. In addition, it was recognized early that the development of a rational methodology for comparing various siting proposals, both in terms of the extent of the facilities to be constructed at any given site and in terms of the selection of the best site among a range of alternatives, would be necessary. Indeed, this decision has already been confirmed in that its appropriateness has survived the rather severe changes in the nuclear fuel cycle policy that have occurred in the past year. Indeed, the very fact that these changes have occurred and comparable alterations in basic policy may be expected in the future, tend to emphasize the necessity for developing logical and rational methods of system evaluation which have the inherent flexibility necessary to reflect these various policy options. In carrying out the study the full scope of technical expertise available has been brought to bear on the various appropriate parts of the overall study. Coordination between these various investigators throughout this period has been open, productive, and, in some cases, spirited. The resolution of many of the questions raised in this initial phase of the study has contributed significantly to the development of the siting methodology. An assessment of the existing regulatory climate as it reflects throughout the appropriate position in the federal establishment has been completed. Identification of comparable material at the state level is certainly a more diffuse and uncertain process. Demonstration of the workability of the siting methodology is currently one of the major objectives of the next year of study. That objective should be met within the presently defined program schedule and budget

  13. Evaluating the use of sharpened land surface temperature for daily evapotranspiration estimation over irrigated crops in arid lands

    Rosas, Jorge

    2014-12-01

    Satellite remote sensing provides data on land surface characteristics, useful for mapping land surface energy fluxes and evapotranspiration (ET). Land-surface temperature (LST) derived from thermal infrared (TIR) satellite data has been reliably used as a remote indicator of ET and surface moisture status. However, TIR imagery usually operates at a coarser resolution than that of shortwave sensors on the same satellite platform, making it sometimes unsuitable for monitoring of field-scale crop conditions. This study applies the data mining sharpener (DMS; Gao et al., 2012) technique to data from the Moderate Resolution Imaging Spectroradiometer (MODIS), which sharpens the 1 km thermal data down to the resolution of the optical data (250-500 m) based on functional LST and reflectance relationships established using a flexible regression tree approach. The DMS approach adopted here has been enhanced/refined for application over irrigated farming areas located in harsh desert environments in Saudi Arabia. The sharpened LST data is input to an integrated modeling system that uses the Atmosphere-Land Exchange Inverse (ALEXI) model and associated flux disaggregation scheme (DisALEXI) in conjunction with model reanalysis data and remotely sensed data from polar orbiting (MODIS) and geostationary (MSG; Meteosat Second Generation) satellite platforms to facilitate daily estimates of evapotranspiration. Results are evaluated against available flux tower observations over irrigated maize near Riyadh in Saudi Arabia. Successful monitoring of field-scale changes in surface fluxes are of importance towards an efficient water use in areas where fresh water resources are scarce and poorly monitored. Gao, F.; Kustas, W.P.; Anderson, M.C. A Data Mining Approach for Sharpening Thermal Satellite Imagery over Land. Remote Sens. 2012, 4, 3287-3319.

  14. LAND SUITABILITY SCENARIOS FOR ARID COASTAL PLAINS USING GIS MODELING: SOUTHWESTERN SINAI COASTAL PLAIN, EGYPT

    Ahmed Mohamed Wahid

    2009-12-01

    Full Text Available Site selection analysis was carried out to find the best suitable lands for development activities in an example of promising coastal plains, southwestern Sinai, Egypt. Two GIS models were developed to represent two scenarios of land use suitability in the study area using GIS Multi Criteria Analysis Modeling. The factors contributed in the analysis are the Topography, Land cover, Existing Land use, Flash flood index, Drainage lines and Water points. The first scenario was to classify the area according to various gradual ranges of suitability. According to this scenario, the area is classified into five classes of suitability. The percentage of suitability values are 51.16, 6.13, 22.32, 18.49 and 1.89% for unsuitable, least suitable, low suitable, suitable and high suitable, respectively. The second scenario is developed for a particular kind of land use planning; tourism and recreation projects. The suitability map of this scenario was classified into five values. Unsuitable areas represent 51.18% of the study area, least suitable 16.67%, low suitable 22.85%, suitable 8.61%, and high suitable 0.68%. The best area for locating development projects is the area surrounding El-Tor City and close to the coast. This area could be an urban extension of El-Tor City with more economical and environmental management.

  15. Land Surface Model and Particle Swarm Optimization Algorithm Based on the Model-Optimization Method for Improving Soil Moisture Simulation in a Semi-Arid Region.

    Yang, Qidong; Zuo, Hongchao; Li, Weidong

    2016-01-01

    Improving the capability of land-surface process models to simulate soil moisture assists in better understanding the atmosphere-land interaction. In semi-arid regions, due to limited near-surface observational data and large errors in large-scale parameters obtained by the remote sensing method, there exist uncertainties in land surface parameters, which can cause large offsets between the simulated results of land-surface process models and the observational data for the soil moisture. In this study, observational data from the Semi-Arid Climate Observatory and Laboratory (SACOL) station in the semi-arid loess plateau of China were divided into three datasets: summer, autumn, and summer-autumn. By combing the particle swarm optimization (PSO) algorithm and the land-surface process model SHAW (Simultaneous Heat and Water), the soil and vegetation parameters that are related to the soil moisture but difficult to obtain by observations are optimized using three datasets. On this basis, the SHAW model was run with the optimized parameters to simulate the characteristics of the land-surface process in the semi-arid loess plateau. Simultaneously, the default SHAW model was run with the same atmospheric forcing as a comparison test. Simulation results revealed the following: parameters optimized by the particle swarm optimization algorithm in all simulation tests improved simulations of the soil moisture and latent heat flux; differences between simulated results and observational data are clearly reduced, but simulation tests involving the adoption of optimized parameters cannot simultaneously improve the simulation results for the net radiation, sensible heat flux, and soil temperature. Optimized soil and vegetation parameters based on different datasets have the same order of magnitude but are not identical; soil parameters only vary to a small degree, but the variation range of vegetation parameters is large.

  16. GRACE Gravity Satellite Observations of Terrestrial Water Storage Changes for Drought Characterization in the Arid Land of Northwestern China

    Yanping Cao

    2015-01-01

    Full Text Available Drought is a complex natural hazard which can have negative effects on agriculture, economy, and human life. In this paper, the primary goal is to explore the application of the Gravity Recovery and Climate Experiment (GRACE gravity satellite data for the quantitative investigation of the recent drought dynamic over the arid land of northwestern China, a region with scarce hydrological and meteorological observation datasets. The spatiotemporal characteristics of terrestrial water storage changes (TWSC were first evaluated based on the GRACE satellite data, and then validated against hydrological model simulations and precipitation data. A drought index, the total storage deficit index (TSDI, was derived on the basis of GRACE-recovered TWSC. The spatiotemporal distributions of drought events from 2003 to 2012 in the study region were obtained using the GRACE-derived TSDI. Results derived from TSDI time series indicated that, apart from four short-term (three months drought events, the study region experienced a severe long-term drought from May 2008 to December 2009. As shown in the spatial distribution of TSDI-derived drought conditions, this long-term drought mainly concentrated in the northwestern area of the entire region, where the terrestrial water storage was in heavy deficit. These drought characteristics, which were detected by TSDI, were consistent with local news reports and other researchers’ results. Furthermore, a comparison between TSDI and Standardized Precipitation Index (SPI implied that GRACE TSDI was a more reliable integrated drought indicator (monitoring agricultural and hydrological drought in terms of considering total terrestrial water storages for large regions. The GRACE-derived TSDI can therefore be used to characterize and monitor large-scale droughts in the arid regions, being of special value for areas with scarce observations.

  17. Land Surface Temperature Retrieval from MODIS Data by Integrating Regression Models and the Genetic Algorithm in an Arid Region

    Ji Zhou

    2014-06-01

    Full Text Available The land surface temperature (LST is one of the most important parameters of surface-atmosphere interactions. Methods for retrieving LSTs from satellite remote sensing data are beneficial for modeling hydrological, ecological, agricultural and meteorological processes on Earth’s surface. Many split-window (SW algorithms, which can be applied to satellite sensors with two adjacent thermal channels located in the atmospheric window between 10 μm and 12 μm, require auxiliary atmospheric parameters (e.g., water vapor content. In this research, the Heihe River basin, which is one of the most arid regions in China, is selected as the study area. The Moderate-resolution Imaging Spectroradiometer (MODIS is selected as a test case. The Global Data Assimilation System (GDAS atmospheric profiles of the study area are used to generate the training dataset through radiative transfer simulation. Significant correlations between the atmospheric upwelling radiance in MODIS channel 31 and the other three atmospheric parameters, including the transmittance in channel 31 and the transmittance and upwelling radiance in channel 32, are trained based on the simulation dataset and formulated with three regression models. Next, the genetic algorithm is used to estimate the LST. Validations of the RM-GA method are based on the simulation dataset generated from in situ measured radiosonde profiles and GDAS atmospheric profiles, the in situ measured LSTs, and a pair of daytime and nighttime MOD11A1 products in the study area. The results demonstrate that RM-GA has a good ability to estimate the LSTs directly from the MODIS data without any auxiliary atmospheric parameters. Although this research is for local application in the Heihe River basin, the findings and proposed method can easily be extended to other satellite sensors and regions with arid climates and high elevations.

  18. Modelling the topsoil carbon stock of agricultural lands with the Stochastic Gradient Treeboost in a semi-arid Mediterranean region

    Schillaci, Calogero

    2016-10-29

    ETM+ panchromatic Band 8 were the most important predictors of SOC stock. Finally, SOC stocks were estimated for each land cover class. SGT predicted SOC stock better than GSOC and ISRIC for most data. This resulted in a percentage of data in the prediction confidence interval ± 50% compared to the observed values of 71.4%, 65.8%, and 50.7% for SGT, GSOC, and SGT, respectively. This consisted of a higher R2 and a slope (β) that was closer to 1 for the pseudo-regression constructed with SGT compared to GSOC and ISRIC. In conclusion, the results of the present study showed that the integration of RS with climatic and soil texture spatial data could strongly improve SOC prediction in a semi-arid Mediterranean region. In addition, the panchromatic band of Landsat 7 ETM + was more predictive compared to the conventionally used NDVI. This information is crucial to guiding decision-making processes, especially at a regional scale and/or in semi-arid Mediterranean areas. The model performance of the SGT could be further improved by adopting predictors with greater spatial resolutions. The results of the present experiment yield valuable information, especially for assessing climate change or land use change scenarios for SOC stocks and their spatial distribution.

  19. Modelling the topsoil carbon stock of agricultural lands with the Stochastic Gradient Treeboost in a semi-arid Mediterranean region

    Schillaci, Calogero; Lombardo, Luigi; Saia, Sergio; Fantappiè , Maria; Mä rker, Michael; Acutis, Marco

    2016-01-01

    ETM+ panchromatic Band 8 were the most important predictors of SOC stock. Finally, SOC stocks were estimated for each land cover class. SGT predicted SOC stock better than GSOC and ISRIC for most data. This resulted in a percentage of data in the prediction confidence interval ± 50% compared to the observed values of 71.4%, 65.8%, and 50.7% for SGT, GSOC, and SGT, respectively. This consisted of a higher R2 and a slope (β) that was closer to 1 for the pseudo-regression constructed with SGT compared to GSOC and ISRIC. In conclusion, the results of the present study showed that the integration of RS with climatic and soil texture spatial data could strongly improve SOC prediction in a semi-arid Mediterranean region. In addition, the panchromatic band of Landsat 7 ETM + was more predictive compared to the conventionally used NDVI. This information is crucial to guiding decision-making processes, especially at a regional scale and/or in semi-arid Mediterranean areas. The model performance of the SGT could be further improved by adopting predictors with greater spatial resolutions. The results of the present experiment yield valuable information, especially for assessing climate change or land use change scenarios for SOC stocks and their spatial distribution.

  20. Small Ruminant Production System Efficiency under Abu-Dhabi, United Arab Emirates Arid Land Conditions

    Eihab Fathelrahman

    2014-12-01

    Full Text Available Sheep and goat production systems in the United Arab Emirates (UAE operate under scarce natural resource constraints. A cross-sectional survey that covered 661 mixed farms, including major sheep and goat production, was conducted in the three regions of Abu Dhabi Emirate (Al-Ain, Western Region and Abu Dhabi city during 2012. A Cobb-Douglas, double-logarithmic stochastic frontier production function and maximum likelihood estimation were applied to estimate important economic derivatives and the associated risk of small ruminant production in this arid area. The highest impact of an input on the output level was found to be labor for raising sheep and alfalfa grass for raising goats. Both labor and alfalfa variables were found to be overutilized for sheep and goat production, respectively. Overall, the results indicate that average technical efficiency is 0.62 for raising sheep and only 0.34 for raising goats in the study area. Technical efficiency analysis included measuring the frequency of farms at each level of estimated technical efficiency in the range between zero and one. Zero for the technical efficiency coefficient indicates a lack of technical efficiency in resource use. The results of this study indicated that only 1% of the sheep farms show a technical efficiency coefficient of 0.25 or less; the same can be said for 41% of goat producers. However, these technical efficiencies were found to be more than 0.75 for 12% and 5% of the sheep and goat farms, respectively. Overall, goat farming in the UAE was found to be less efficient than sheep production. The results also indicated that flock size and type of breed were the most influential factors relative to other factors, and both show a positive relationship with technical efficiency. Other than flock size, factors, such as owners’ years of experience and management practices, were found to be more influential on goat farming system efficiency relative to sheep farming.

  1. Impact of grazing on range plant community components under arid Mediterranean climate in northern Syria

    Niane, A.A.

    2013-01-01

    Keywords: Rotational grazing, full protection, continuous grazing species richness,

    species diversity, soil seed bank, Bayesian methods, Salsola vermiculata, seed

    longevity, rangeland management, Syria.

    Rangelands represent 70% of the semi-arid and arid

  2. Energy, material and land requirement of a fusion plant

    Schleisner, Liselotte; Hamacher, T.; Cabal, H.

    2001-01-01

    The energy and material necessary to construct a power plant and the land covered by the plant are indicators for the ‘consumption’ of environment by a certain technology. Based on current knowledge, estimations show that the material necessary to construct a fusion plant will exceed the material...... requirement of a fission plant by a factor of two. The material requirement for a fusion plant is roughly 2000 t/MW and little less than 1000 t/MW for a fission plant. The land requirement for a fusion plant is roughly 300 m2/MW and the land requirement for a fission plant is a little less than 200 m2/MW...... less ‘environment’ for the construction than renewable technologies, especially wind and solar....

  3. Algal ancestor of land plants was preadapted for symbiosis.

    Delaux, Pierre-Marc; Radhakrishnan, Guru V; Jayaraman, Dhileepkumar; Cheema, Jitender; Malbreil, Mathilde; Volkening, Jeremy D; Sekimoto, Hiroyuki; Nishiyama, Tomoaki; Melkonian, Michael; Pokorny, Lisa; Rothfels, Carl J; Sederoff, Heike Winter; Stevenson, Dennis W; Surek, Barbara; Zhang, Yong; Sussman, Michael R; Dunand, Christophe; Morris, Richard J; Roux, Christophe; Wong, Gane Ka-Shu; Oldroyd, Giles E D; Ané, Jean-Michel

    2015-10-27

    Colonization of land by plants was a major transition on Earth, but the developmental and genetic innovations required for this transition remain unknown. Physiological studies and the fossil record strongly suggest that the ability of the first land plants to form symbiotic associations with beneficial fungi was one of these critical innovations. In angiosperms, genes required for the perception and transduction of diffusible fungal signals for root colonization and for nutrient exchange have been characterized. However, the origin of these genes and their potential correlation with land colonization remain elusive. A comprehensive phylogenetic analysis of 259 transcriptomes and 10 green algal and basal land plant genomes, coupled with the characterization of the evolutionary path leading to the appearance of a key regulator, a calcium- and calmodulin-dependent protein kinase, showed that the symbiotic signaling pathway predated the first land plants. In contrast, downstream genes required for root colonization and their specific expression pattern probably appeared subsequent to the colonization of land. We conclude that the most recent common ancestor of extant land plants and green algae was preadapted for symbiotic associations. Subsequent improvement of this precursor stage in early land plants through rounds of gene duplication led to the acquisition of additional pathways and the ability to form a fully functional arbuscular mycorrhizal symbiosis.

  4. Characterising root density of peach trees in a semi-arid Chernozem to increase plant density

    Paltineanu, Cristian; Septar, Leinar; Gavat, Corina; Chitu, Emil; Oprita, Alexandru; Moale, Cristina; Calciu, Irina; Vizitiu, Olga; Lamureanu, Gheorghe

    2016-01-01

    The available information on root system in fully mature peach orchards in semi-arid regions is insufficient. This paper presents a study on the root system density in an irrigated peach orchard from Dobrogea, Romania, using the trench technique. The old orchard has clean cultivation in inter-row and in-row. The objectives of the study were to: test the hypothesis that the roots of fully mature peach trees occupy the whole soil volume; find out if root repulsive effect of adjacent plants occurred for the rootstocks and soil conditions; find relationships between root system and soil properties and analyse soil state trend. Some soil physical properties were significantly deteriorated in inter-row versus in-row, mainly due to soil compaction induced by technological traffic. Density of total roots was higher in-row than inter-row, but the differences were not significant. Root density decreased more intensely with soil depth than with distance from tree trunks. Root density correlated with some soil properties. No repulsive effect of the roots of adjacent peach trees was noted. The decrease of root density with distance from trunk can be used in optimising tree arrangement. The conclusions could also be used in countries with similar growth conditions.

  5. Study on Rangeland production Potential and its Limitations in the Semi-Arid lands of Northern Kenya

    Keya, G.A.; Hornetz, B.

    1999-01-01

    Results obtained from recent studies focused on rangeland potential as influenced by human activity and climatic factors in the semi-arid and pastoral ecosystems of Northern Kenya indicated great temporal and spatial forage production variability. The objective of the studies was to document the primary production potential in relation to water stress (drought), herbivory and direct human activities. Efforts also focused on finding possibilities of increasing productivity while conserving the finite resources for sustainable use. Laboratory field and numeric methods were employed over several seasons and years. Forb and grass production was more viable than that of the brows (dwarf shrub) layer. Compared to forbs and dwarf shrubs, The grass layer contributed less to the total of production in all seasons, indicating that the region had less potential for grazers compared to browsers. Spatial-temporal variations in rangeland carrying capacity reflected the great spatial heterogeneity in vegetation types and production. Similarly, seasonal difference were very evident, with highest estimates in the long rainy and lowest during the dry and short rainy seasons, respectively. Factors limiting rangeland production potential and were identified to be moisture deficiency, resource-use conflicts, an increasing and partial sedentarised nomadic population, overgrazing, tree felling, and land degradation (desert encroachment). Measures that can increase rangelands production potential and provide a better way of life for the inhabitants of the region include: (a) identification of land degradation (e.g. by means of bio-indicators and Geographical Information systems, GIS); (b) technical interventions (i.e. soil and water conservation,restoration of degraded ares, fodder production); (c)socio-economic interventions (i.e. resolution of resource-use conflicts, alleviation of poverty, infrastructure development, improvement of livestock marketing channels, etc) and (d) continued

  6. Performance and effects of land cover type on synthetic surface reflectance data and NDVI estimates for assessment and monitoring of semi-arid rangeland

    Olexa, Edward M.; Lawrence, Rick L

    2014-01-01

    Federal land management agencies provide stewardship over much of the rangelands in the arid andsemi-arid western United States, but they often lack data of the proper spatiotemporal resolution andextent needed to assess range conditions and monitor trends. Recent advances in the blending of com-plementary, remotely sensed data could provide public lands managers with the needed information.We applied the Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM) to five Landsat TMand concurrent Terra MODIS scenes, and used pixel-based regression and difference image analyses toevaluate the quality of synthetic reflectance and NDVI products associated with semi-arid rangeland. Pre-dicted red reflectance data consistently demonstrated higher accuracy, less bias, and stronger correlationwith observed data than did analogous near-infrared (NIR) data. The accuracy of both bands tended todecline as the lag between base and prediction dates increased; however, mean absolute errors (MAE)were typically ≤10%. The quality of area-wide NDVI estimates was less consistent than either spectra lband, although the MAE of estimates predicted using early season base pairs were ≤10% throughout the growing season. Correlation between known and predicted NDVI values and agreement with the 1:1regression line tended to decline as the prediction lag increased. Further analyses of NDVI predictions,based on a 22 June base pair and stratified by land cover/land use (LCLU), revealed accurate estimates through the growing season; however, inter-class performance varied. This work demonstrates the successful application of the STARFM algorithm to semi-arid rangeland; however, we encourage evaluation of STARFM’s performance on a per product basis, stratified by LCLU, with attention given to the influence of base pair selection and the impact of the time lag.

  7. Monitoring and Analysing Land Use/Cover Changes in an Arid Region Based on Multi-Satellite Data: The Kashgar Region, Northwest China

    Ayisulitan Maimaitiaili

    2018-01-01

    Full Text Available In arid regions, oases ecosystems are fragile and sensitive to climate change, and water is the major limiting factor for environmental and socio-economic developments. Understanding the drivers of land use/cover change (LUCC in arid regions is important for the development of management strategies to improve or prevent environmental deterioration and loss of natural resources. The Kashgar Region is the key research area in this study; it is a typical mountain-alluvial plain-oasis-desert ecosystem in an arid region, and is one of the largest oases in Xinjiang Uyghur Autonomous Region, China. In addition, the Kashgar Region is an important cotton and grain production area. This study’s main objectives are to quantify predominant LUCCs and identify their driving forces, based on the integration of multiple remote sensors and applications of environmental and socio-economic data. Results showed that LUCCs have been significant in the Kashgar Region during the last 42 years. Cultivated land and urban/built-up lands were the most changed land cover (LC, by 3.6% and 0.4% from 1972 to 10.2% and 3% in 2014, respectively. By contrast, water and forest areas declined. Grassland and snow-covered areas have fluctuated along with climate and human activities. Bare land was changed slightly from 1972 to 2014. According to the land use transfer matrix, cultivated land replaced grass- and forestland. Urban/built-up land mainly expanded over cultivated and bare land. LUCCs were triggered by the interplay of natural and social drivers. Increasing runoff, caused by regional climate changes in seasonal variation, and snow melt water, have provided water resources for LC changes. In the same way, population growth, changes in land tenure, and socio-economic development also induced LUCCs. However, expansion of cultivated land and urban/built-up land led to increased water consumption and stressed fragile water systems during on-going climate changes. Therefore

  8. CMIP5 land surface models systematically underestimate inter-annual variability of net ecosystem exchange in semi-arid southwestern North America.

    MacBean, N.; Scott, R. L.; Biederman, J. A.; Vuichard, N.; Hudson, A.; Barnes, M.; Fox, A. M.; Smith, W. K.; Peylin, P. P.; Maignan, F.; Moore, D. J.

    2017-12-01

    Recent studies based on analysis of atmospheric CO2 inversions, satellite data and terrestrial biosphere model simulations have suggested that semi-arid ecosystems play a dominant role in the interannual variability and long-term trend in the global carbon sink. These studies have largely cited the response of vegetation activity to changing moisture availability as the primary mechanism of variability. However, some land surface models (LSMs) used in these studies have performed poorly in comparison to satellite-based observations of vegetation dynamics in semi-arid regions. Further analysis is therefore needed to ensure semi-arid carbon cycle processes are well represented in global scale LSMs before we can fully establish their contribution to the global carbon cycle. In this study, we evaluated annual net ecosystem exchange (NEE) simulated by CMIP5 land surface models using observations from 20 Ameriflux sites across semi-arid southwestern North America. We found that CMIP5 models systematically underestimate the magnitude and sign of NEE inter-annual variability; therefore, the true role of semi-arid regions in the global carbon cycle may be even more important than previously thought. To diagnose the factors responsible for this bias, we used the ORCHIDEE LSM to test different climate forcing data, prescribed vegetation fractions and model structures. Climate and prescribed vegetation do contribute to uncertainty in annual NEE simulations, but the bias is primarily caused by incorrect timing and magnitude of peak gross carbon fluxes. Modifications to the hydrology scheme improved simulations of soil moisture in comparison to data. This in turn improved the seasonal cycle of carbon uptake due to a more realistic limitation on photosynthesis during water stress. However, the peak fluxes are still too low, and phenology is poorly represented for desert shrubs and grasses. We provide suggestions on model developments needed to tackle these issues in the future.

  9. Co-evolution of land use changes, water quality deterioration and social conflicts in arid Northern Chile

    Zang, Carina; Dame, Juliane

    2017-04-01

    Water scarcity concerns not only the limited availability of water but also water of inadequate quality in terms of its designated purposes. Arid regions, such as found in Northern Chile, are especially vulnerable to water contamination, owing to missing dilution. Additionally, the national government of Chile's goal to make the country a globally important food exporter has led to the widespread expansion of agricultural surfaces over the last 20 years, thereby increasing pressure on limited water resources and water quality. Mining, being one of the most important economic sectors in Chile, threatens both surface and groundwater quality. This scenario increases the potential for water use conflicts, which is further compounded by the demand for potable water provided by rivers and groundwater. In order to better understand the role of both physical and human dimensions of water quality, this research uses a socio-hydrological conceptual framework. This approach is used in order to broaden the scope of hydrology to include the anthropogenic impact on the environment. It therefore focuses on human and natural interactions and two-sided feedback loops, instead of purely hydrological cycles. Using the case study of the Rio Huasco watershed changes in water quality, which originate at the nexus of physical parameters, social conflicts and changing land use regimes in Northern Chile, are discussed. This region was chosen as an exemplary case for the development of Chile's arid regions: the valley is located at the southern edge of the Atacama Desert, where water scarcity is a major problem. At present, the watershed is predominantly used for agriculture. Many small farmers still practise strip cultivation, but are pressured to shift towards an international export-orientated future with monocultures. International companies are planning to mine the Pascua Lama Mine, one of the world's biggest gold reserves located in the headwaters of the Rio Huasco. Meanwhile, the

  10. Screening Prosopis (mesquite) species for biofuel production on semi-arid lands. Final report, April 1, 1978-March 30, 1981

    Felker, P; Cannell, G H; Clark, P R; Osborn, J F; Nash, P

    1985-01-01

    Arid adapted nitrogen fixing trees and shrubs of the genus Prosopis (mesquite) have been examined for woody biomass production on semi-arid lands of southwestern United States. A germ-plasm collection of 900 accessions from North and South America and Africa was assembled. Field studies screening for biomass production, frost tolerance, response to irrigation, pod production and heat/drought tolerance involved a total of 80 accessions. Selections made from survivors of coal/frost screening trial had more frost tolerance and biomass productivity than prostrate selections from the ranges of Arizona, New Mexico and west Texas. Thirteen Prosopis species were found to nodulate, reduce acetylene to ethylene, and grow on a nitrogen free media in greenhouse experiments. The salinity tolerance of six Prosopis species was examined on a nitrogen free media in greenhouse experiments. No reduction in growth occurred for any species tested at a salinity of 6000 mg NaC1/L which is considered too saline for normal agricultural crops. Individual trees have grown 5 to 7 cm in basal diameter, and 2.0 to 3.7 meters in height per year and have achieved 50 kg oven dry weight per tree in 2 years with 600 mm water application per year. Vegetative propagation techniques have been developed and clones of these highly productive trees have been made. Small pilots on 1.5 x 1.5 m spacing in the California Imperial Valley had a first and second season dry matter production of 11.7 and 16.9 T/ha for P. chilensis (0009), 7.1 and 6.9 T/ha for P. glandulosa var. torreyana (0001), 9.8 and 19.2 T/ha for P. alba (0039) and 7.9 and 14.5 T/ha for progency of a California ornamental (0163). The projected harvested costs of $25.00 per oven dry ton or $1.50 per million Btu's compare favorable with coal and other alternative fuel sources in South Texas.

  11. In vitro antagonistic activity, plant growth promoting traits and phylogenetic affiliation of rhizobacteria associated with wild plants grown in arid soil.

    El-Sayed, Wael S; Akhkha, Abdellah; El-Naggar, Moustafa Y; Elbadry, Medhat

    2014-01-01

    The role of plant growth-promoting rhizobacteria (PGPR) in adaptation of plants in extreme environments is not yet completely understood. For this study native bacteria were isolated from rhizospeheric arid soils and evaluated for both growth-promoting abilities and antagonistic potential against phytopathogenic fungi and nematodes. The phylogentic affiliation of these representative isolates was also characterized. Rhizobacteria associated with 11 wild plant species from the arid soil of Almadinah Almunawarah, Kingdom of Saudi Arabia (KSA) were investigated. From a total of 531 isolates, only 66 bacterial isolates were selected based on their ability to inhibit Fusarium oxysporum, and Sclerotinia sclerotiorum. The selected isolates were screened in vitro for activities related to plant nutrition and plant growth regulation as well as for antifungal and nematicidal traits. Isolated bacteria were found to exhibit capabilities in fix atmospheric nitrogen, produce ammonia, indoleacetic acid (IAA), siderophores, solubilize phosphate and zinc, and showed an antagonistic potential against some phytopathogenic fungi and one nematode species (Meloidogyne incognita) to various extent. Isolates were ranked by their potential ability to function as PGPR. The 66 isolates were genotyped using amplified rDNA restriction analysis (ARDRA) and 16S rRNA gene sequence analysis. The taxonomic composition of the representative genotypes from both rhizosphere and rhizoplane comprised Bacillus, Enterobacter and Pseudomonas. Out of the 10 genotypes, three strains designated as PHP03, CCP05, and TAP02 might be regarded as novel strains based on their low similarity percentages and high bootstrap values. The present study clearly identified specific traits in the isolated rhizobacteria, which make them good candidates as PGPR and might contribute to plant adaption to arid environments. Application of such results in agricultural fields may improve and enhance plant growth in arid soils.

  12. In vitro Antagonistic Activity, Plant Growth Promoting Traits and Phylogenetic Affiliation of Rhizobacteria Associated with Wild Plants Grown in Arid Soil

    Wael Samir El-Sayed

    2014-12-01

    Full Text Available The role of plant growth-promoting rhizobacteria (PGPR in adaptation of plants in extreme environments is not yet completely understood. For this study native bacteria were isolated from rhizospeheric arid soils and evaluated for both growth-promoting abilities and antagonistic potential against phytopathogenic fungi and nematodes. The phylogentic affiliation of these representative isolates was also characterized. Rhizobacteria associated with eleven wild plant species from the arid soil of Almadinah Almunawarah, Kingdom of Saudi Arabia (KSA were investigated. From a total of 531 isolates, only 66 bacterial isolates were selected based on their ability to inhibit Fusarium oxysporum, and Sclerotinia sclerotiorum. The selected isolates were screened in vitro for activities related to plant nutrition and plant growth regulation as well as for antifungal and nematicidal traits. Isolated bacteria were found to exhibit capabilities in fix atmospheric nitrogen, produce ammonia, indoleacetic acid (IAA, siderophores, solubilize phosphate and zinc, and showed an antagonistic potential against some phytopathogenic fungi and one nematode species (Meloidogyne incognita to various extent. Isolates were ranked by their potential ability to function as PGPR. The 66 isolates were genotyped using amplified rDNA restriction analysis (ARDRA and 16S rRNA gene sequence analysis. The taxonomic composition of the representative genotypes from both rhizosphere and rhizoplane comprised Bacillus, Enterobacter and Pseudomonas. Out of the ten genotypes, three strains designated as PHP03, CCP05, and TAP02 might be regarded as novel strains based on their low similarity percentages and high bootstrap values. The present study clearly identified specific traits in the isolated rhizobacteria, which make them good candidates as PGPR and might contribute to plant adaption to arid environments. Application of such results in agricultural fields may improve and enhance plant

  13. Fiscal 1997 report on the survey of biological CO2 fixation using arid land and oligotrophic waters; 1997 nendo chosa hokokusho (kansochi, hin`eiyo kaiiki wo riyoshita seibutsuteki CO2 kotei ni kansuru chosa)

    NONE

    1998-03-01

    This survey is aimed to investigate various measures to be taken for biological CO2 fixation, to synthetically study feasibilities of the measures from various aspects of CO2 fixation mechanism, scale, speed, and environmental effects and technical problems in case of introducing those, and to assess the measures quantitatively. In this fiscal year, a study was proceeded with of possibilities of carbon fixation by afforestation and that by fertilization into ocean. The paper defined significance of afforestation in arid land, and especially advantages in conducting researches in West Australia. Relationships were examined among afforestation, precipitation and topography. The result of the survey was described of water- and salt-transfer simulation methods. Studies of arid land were made in terms of photosynthetic speed, transpiration speed, soil characteristics, measuring methods for precipitation and vaporization amount, and the examples. Seven places of Leonora where water source and water quality were examined were selected, and the measuring results were described. The paper summed up the state of utilization of biomass energy obtained from forest and commented on a scenario on tree-planting. Finally, a possibility was stated of the carbon fixation by fermentation into ocean. 178 refs., 121 figs., 53 tabs.

  14. Photochemically induced carbon dioxide production as a mechanism for carbon loss from plant litter in arid ecosystems

    Brandt, L. A.; Bohnet, C.; King, J. Y.

    2009-06-01

    We investigated the potential for abiotic mineralization to carbon dioxide (CO2) via photodegradation to account for carbon (C) loss from plant litter under conditions typical of arid ecosystems. We exposed five species of grass and oak litter collected from arid and mesic sites to a factorial design of ultraviolet (UV) radiation (UV pass, UV block), and sterilization under dry conditions in the laboratory. UV pass treatments produced 10 times the amount of CO2 produced in UV block treatments. CO2 production rates were unaffected by litter chemistry or sterilization. We also exposed litter to natural solar radiation outdoors on clear, sunny days close to the summer solstice at midlatitudes and found that UV radiation (280-400 nm) accounted for 55% of photochemically induced CO2 production, while shortwave visible radiation (400-500 nm) accounted for 45% of CO2 production. Rates of photochemically induced CO2 production on a per-unit-mass basis decreased with litter density, indicating that rates depend on litter surface area. We found no evidence for leaching, methane production, or facilitation of microbial decomposition as alternative mechanisms for significant photochemically induced C loss from litter. We conclude that abiotic mineralization to CO2 is the primary mechanism by which C is lost from litter during photodegradation. We estimate that CO2 production via photodegradation could be between 1 and 4 g C m-2 a-1 in arid ecosystems in the southwestern United States. Taken together with low levels of litter production in arid systems, photochemical mineralization to CO2 could account for a significant proportion of annual carbon loss from litter in arid ecosystems.

  15. Food source quality and ant dominance hierarchy influence the outcomes of ant-plant interactions in an arid environment

    Flores-Flores, Rocío Vianey; Aguirre, Armando; Anjos, Diego V.; Neves, Frederico S.; Campos, Ricardo I.; Dáttilo, Wesley

    2018-02-01

    In this study, we conducted a series of experiments in a population of Vachellia constricta (Fabaceae) in the arid Tehuacan-Cuicatláan valley, Mexico, in order to evaluate if the food source quality and ant dominance hierarchy influence the outcomes of ant-plant interactions. Using an experiment with artificial nectaries, we observed that ants foraging on food sources with higher concentration of sugar are quicker in finding and attacking potential herbivorous insects. More specifically, we found that the same ant species may increase their defence effectiveness according to the quality of food available. These findings indicate that ant effectiveness in plant protection is context-dependent and may vary according to specific individual characteristics of plants. In addition, we showed that competitively superior ant species tend to dominate plants in periods with high nectar activity, emphasizing the role of the dominance hierarchy structuring ant-plant interactions. However, when high sugar food sources were experimentally available ad libitum, the nocturnal and competitively superior ant species, Camponotus atriceps, did not dominate the artificial nectaries during the day possibly due to limitation of its thermal tolerance. Therefore, temporal niche partitioning may be allowing the coexistence of two dominant ant species (Camponotus rubritorax during the day and C. atriceps at night) on V. constricta. Our findings indicate that the quality of the food source, and temporal shifts in ant dominance are key factors which structure the biotic plant defences in an arid environment.

  16. Effect of Planting Date on Reducing Growth Period of Spring Safflower Cultivars in Tabriz Cold and Semi-arid Climate

    B Pasban Eslam

    2018-02-01

    Full Text Available Introduction Safflower is a plant adaptable to areas with limited rainfall during winter and spring and dry air at flowering, seed filling and maturity stages, and tolerant to water deficit. The positive correlation coefficient observed between safflower seed yield with precipitation and low air temperature during seed germination to flowering and flowering to seed maturity. Furthermore, precipitation and low temperature during flowering to seed maturity significantly increased seed oil percentage. Therefore, it seems that, by adjusting the planting time can be adapted phenological stages of plant with appropriate weather conditions. The aims of this research were study the possibility reducing the growth period of safflower spring varieties with maintaining performance through delay in planting time, evaluate seed and oil yields at different planting times, and identify the best varieties for cold and semi-arid areas. Materials and Methods The experiment was conducted at the East Azarbaijan Agriculture and Natural Resources Research Center (46°2¢E, 37°58¢N, 1347 m a.s.l. during 2014-2015 growing season. According to Koppen climatic classification system, the area climate is semi-arid and cold. This study was carried out as factorial experiment based on randomized complete block design with three replications. Treatments were four planting dates (30 March, 9, 19 and 29 April and three safflower spring cultivars (Sina, Soffeh and Goldasht. Plant spacing between rows was 24 cm and final plant density was 70 plant per m2. Each plot consisted of 6 rows in 5 meters. Plants were harvested on the 11th and 14th of August in the first and second years of experiment, respectively. At the harvest time, in order to control boarder effects, plants from the sides of each plot were removed. Measured traits were plant height, capitulum diameter, seed yield, capitula number per plant, seed number per capitulum and 1000-seed weight. Ten plants in each plot

  17. Modeling the Land Use/Cover Change in an Arid Region Oasis City Constrained by Water Resource and Environmental Policy Change using Cellular Automata Model

    Hu, X.; Li, X.; Lu, L.

    2017-12-01

    Land use/cover change (LUCC) is an important subject in the research of global environmental change and sustainable development, while spatial simulation on land use/cover change is one of the key content of LUCC and is also difficult due to the complexity of the system. The cellular automata (CA) model had an irreplaceable role in simulating of land use/cover change process due to the powerful spatial computing power. However, the majority of current CA land use/cover models were binary-state model that could not provide more general information about the overall spatial pattern of land use/cover change. Here, a multi-state logistic-regression-based Markov cellular automata (MLRMCA) model and a multi-state artificial-neural-network-based Markov cellular automata (MANNMCA) model were developed and were used to simulate complex land use/cover evolutionary process in an arid region oasis city constrained by water resource and environmental policy change, the Zhangye city during the period of 1990-2010. The results indicated that the MANNMCA model was superior to MLRMCA model in simulated accuracy. These indicated that by combining the artificial neural network with CA could more effectively capture the complex relationships between the land use/cover change and a set of spatial variables. Although the MLRMCA model were also some advantages, the MANNMCA model was more appropriate for simulating complex land use/cover dynamics. The two proposed models were effective and reliable, and could reflect the spatial evolution of regional land use/cover changes. These have also potential implications for the impact assessment of water resources, ecological restoration, and the sustainable urban development in arid areas.

  18. Assess the potential of solar irrigation systems for sustaining pasture lands in arid regions - A case study in Northwestern China

    Yu, Yingdong; Liu, Jiahong; Wang, Hao; Liu, Miao

    2011-01-01

    Highlights: → We figured out the appropriate indicators for solar irrigation. → We analyzed the economic benefits of solar irrigation system. → The geographic allocation of grasslands suitable for solar irrigation in Qinghai province is presented. → The appropriate region for solar irrigation is also discussed. → The problems and countermeasures of PV pumping irrigation are considered. - Abstract: The combined impact of global climate change and increasing human activities has led to the severe deterioration of grasslands in China. Using the solar irrigation systems is an effective way for sustaining pasture lands in arid regions. A solar irrigation system is the device that uses the solar cell from the sun's radiation to generate electricity for driving the pump. And photovoltaic pump consists of an array of photovoltaic cells and pumps water from a well or reservoir for irrigation. Although ecologists and organizations constantly work and find ways to conserve grasslands through irrigation systems that use solar energy, issues on water resources are not yet thoroughly discussed. This paper takes into account the main factors in the study of water resources, including precipitation and groundwater, to analyze the feasibility of using a photovoltaic (PV) pumping irrigation. The appropriate area for such a PV pumping irrigation in Qinghai Province is also presented. The results show that the grasslands appropriate for PV pumping cover about 8.145 million ha, accounting for 22.3% of the grasslands in the entire province. Finally, the problems and countermeasures of PV pumping irrigation, including the impact on regional water balance, groundwater level and highland permafrost, are also considered.

  19. Relation between seasonally detrended shortwave infrared reflectance data and land surface moisture in semi-arid Sahel

    Olsen, Jørgen Lundegaard; Ceccato, Pietro; Proud, Simon Richard

    2013-01-01

    in vegetation moisture status, and is compared to detrended time series of the Normalized Difference Vegetation Index (NDVI). It was found that when plant available water is low, the SIWSI anomalies increase over time, while the NDVI anomalies decrease over time, but less systematically. Therefore SIWSI may......In the Sudano-Sahelian areas of Africa droughts can have serious impacts on natural resources, and therefore land surface moisture is an important factor. Insufficient conventional sites for monitoring land surface moisture make the use of Earth Observation data for this purpose a key issue...... Second Generation (MSG) satellite. We focused on responses in surface reflectance to soil- and surface moisture for bare soil and early to mid- growing season. A method for implementing detrended time series of the Shortwave Infrared Water Stress Index (SIWSI) is examined for detecting variations...

  20. Grazing exclusion, substrate type, and drought frequency affect plant community structure in rangelands of the arid unpredictable Arabian Deserts

    El-Keblawy, Ali; El-Sheikh, Mohamed

    2017-04-01

    Grazing and drought can adversely affect the ecology and management of rangeland ecosystems. Several management actions have been applied to restore species diversity and community structure in degraded rangelands of the unpredictable arid environment. Protection from grazing is considered as a proper approach for restoration of degraded rangelands, but this depends on substrate type and sometime is hindered with water deficiency (drought). In this study, the effect of protection from grazing animals on species diversity and plant community structure was assessed after a dry and wet periods in both sandy and gravelly substrates in the Dubai Desert Conservation reserve (DDCR), United Arab Emirates. Two sites were selected during November 2012 on the two substrate types (fixed sandy flat and gravel plain) in the arid DDCR. An enclosure was established in each site. Plant community attributes (plant cover, density, frequency, species composition, and diversity indices) were assessed in a number of permanent plots laid inside and outside each enclosure during November 2012, April 2014 and April 2016. The results showed that protection improved clay content, but decreased the organic matters. Interestingly, the protection reduced the concentrations of most estimated nutrients, which could be attributed to the high turnover rate of nutrients associated grazing and low decomposition of accumulated dry plants of non-protected sites. Protection significantly increased all plant community attributes, but the only significant effect was for plant density. Plant density was almost twice greater inside than outside the enclosures. During the dry period, protection resulted in significantly greater deterioration in cover, density and all diversity indices in gravel, compared to sandy sites. Most of the grasses and shrubby plants had died in the gravel plains. However, plant community of the gravel plains was significantly restored after receiving considerable rainfalls. The

  1. Use of carbon isotope analysis to understand semi-arid erosion dynamics and long-term semi-arid land degradation.

    Turnbull, Laura; Brazier, Richard E; Wainwright, John; Dixon, Liz; Bol, Roland

    2008-06-01

    Many semi-arid areas worldwide are becoming degraded, in the form of C(4) grasslands being replaced by C(3) shrublands, which causes an increase in surface runoff and erosion, and altered nutrient cycling, which may affect global biogeochemical cycling. The prevention or control of vegetation transitions is hindered by a lack of understanding of their temporal and spatial dynamics, particularly in terms of interactions between biotic and abiotic processes. This research investigates (1) the effects of soil erosion on the delta(13)C values of soil organic matter (SOM) throughout the soil profile and its implications for reconstructing vegetation change using carbon-isotope analysis and (2) the spatial properties of erosion over a grass-shrub transition to increase understanding of biotic-abiotic interactions by using delta(13)C signals of eroded material as a sediment tracer. Results demonstrate that the soils over grass-shrub transitions are not in steady state. A complex interplay of factors determines the input of SOM to the surface horizon of the soil and its subsequent retention and turnover through the soil profile. A positive correlation between event runoff and delta(13)C signatures of eroded sediment was found in all plots. This indicates that the delta(13)C signatures of eroded sediment may provide a means of distinguishing between changes in erosion dynamics over runoff events of different magnitudes and over different vegetation types. The development of this technique using delta(13)C signatures of eroded sediment provides a new means of furthering existing understanding of erosion dynamics over vegetation transitions. This is critical in terms of understanding biotic-abiotic feedbacks and the evolution of areas subject to vegetation change in semi-arid environments. John Wiley & Sons, Ltd

  2. Influence of biocrusts coverage on microbial communities from underlying arid lands soils

    Anguita-Maeso, Manuel; Miralles*, Isabel; van Wesemael, Bas; Lázaro, Roberto; Ortega, Raúl; García-Salcedo, José Antonio; Soriano**, Miguel

    2017-04-01

    In regions where the water availability limits the plant cover, biological soil crusts are especially essential in the development of an almost continuous living skin mediating the inputs and outputs across the soil surface boundary. However, the entire area is not covered equally and microbial communities from underlying soils might be influenced by biocrust type and the percentage of biocrust coverage. To clarify this question, we have collected underlying soils from biocrusts samples dominated by i) incipient colonization by cyanobacteria, ii) cyanobacteria, biocrusts formed by the lichens: iii) Diploschistes diacapsis and Squamarina lentigera and iv) Lepraria issidiata from Tabernas desert (southeast of Spain) so as to determine the differences in the microbial communities from these underlying soils at two extremes of its spatial distribution range: one with a high percentage of biocrust coverage and fewer degradation and other with a huge degradation and less percentage of biocrust coverage. DNA from these samples was isolated by using a commercial kit and it was taken as template for metagenomic analysis. We conducted a sequencing of the amplicons V4-V5 of the 16S rRNA gene with Next-Generation Sequencing (NGS) Illumina MiSeq platform and a relative quantity of bacteria and fungi were accomplished by quantitative qPCR of rRNA 16S and ITS1-5.8S, respectively. The high biocrust coverage position revealed the highest number of bacteria per gram of soil (1.64E+09 in L. issidiata, in 1.89E+09 D. diacapsis and S. lentigera, 1.63E+09 in cyanobacteria and 2.08E+09 in incipient colonization by cyanobacteria) whereas the less favourable position according to the percentage of biocrust coverage showed fewer amount (1.16E+09 in L. issidiata, 6.98E+08 in D. diacapsis and S. lentigera, 1.46E+09 in cyanobacteria and 7.92E+08 in incipient cyanobacteria biocrust). Similarly, the amount of fungi per gram of soil presented identical correlation ranging from the favourable

  3. Waste Isolation Pilot Plant land management plan

    1996-01-01

    On October 30, 1992, the WIPP Land Withdrawal Act became law. This Act transferred the responsibility for the management of the WIPP Land Withdrawal Area (WILWA) from the Secretary of the Interior to the Secretary of Energy. In accordance with sections 3(a)(1) and (3) of the Act, these lands open-quotes hor-ellipsis are withdrawn from all forms of entry, appropriation, and disposal under the public land laws hor-ellipsis close quotesand are reserved for the use of the Secretary of Energy open-quotes hor-ellipsis for the construction, experimentation, operation, repair and maintenance, disposal, shutdown, monitoring, decommissioning, and other activities, associated with the purposes of WIPP as set forth in the Department of Energy National Security and Military Applications of Nuclear Energy Act of 1980 and this Act.close quotes. As a complement to this LMP, a MOU has been executed between the DOE and the BLM, as required by section 4(d) of the Act. The state of New Mexico was consulted in the development of the MOU and the associated Statement of Work (SOW)

  4. Waste Isolation Pilot Plant land management plan

    NONE

    1996-05-01

    On October 30, 1992, the WIPP Land Withdrawal Act became law. This Act transferred the responsibility for the management of the WIPP Land Withdrawal Area (WILWA) from the Secretary of the Interior to the Secretary of Energy. In accordance with sections 3(a)(1) and (3) of the Act, these lands {open_quotes}{hor_ellipsis}are withdrawn from all forms of entry, appropriation, and disposal under the public land laws{hor_ellipsis}{close_quotes}and are reserved for the use of the Secretary of Energy {open_quotes}{hor_ellipsis}for the construction, experimentation, operation, repair and maintenance, disposal, shutdown, monitoring, decommissioning, and other activities, associated with the purposes of WIPP as set forth in the Department of Energy National Security and Military Applications of Nuclear Energy Act of 1980 and this Act.{close_quotes}. As a complement to this LMP, a MOU has been executed between the DOE and the BLM, as required by section 4(d) of the Act. The state of New Mexico was consulted in the development of the MOU and the associated Statement of Work (SOW).

  5. Broad phylogenomic sampling and the sister lineage of land plants.

    Ruth E Timme

    Full Text Available The tremendous diversity of land plants all descended from a single charophyte green alga that colonized the land somewhere between 430 and 470 million years ago. Six orders of charophyte green algae, in addition to embryophytes, comprise the Streptophyta s.l. Previous studies have focused on reconstructing the phylogeny of organisms tied to this key colonization event, but wildly conflicting results have sparked a contentious debate over which lineage gave rise to land plants. The dominant view has been that 'stoneworts,' or Charales, are the sister lineage, but an alternative hypothesis supports the Zygnematales (often referred to as "pond scum" as the sister lineage. In this paper, we provide a well-supported, 160-nuclear-gene phylogenomic analysis supporting the Zygnematales as the closest living relative to land plants. Our study makes two key contributions to the field: 1 the use of an unbiased method to collect a large set of orthologs from deeply diverging species and 2 the use of these data in determining the sister lineage to land plants. We anticipate this updated phylogeny not only will hugely impact lesson plans in introductory biology courses, but also will provide a solid phylogenetic tree for future green-lineage research, whether it be related to plants or green algae.

  6. Infiltration and planting pits for improved water management and maize yield in semi-arid Zimbabwe

    Nyakudya, I.W.; Stroosnijder, L.; Nyagumbo, I.

    2014-01-01

    Realising that rainwater harvesting (RWH) improves crop productivity, smallholder farmers in semi-arid Zimbabwe modified contour ridges traditionally used for rainwater management by digging infiltration pits inside contour ridge channels in order to retain more water in crop fields. However,

  7. Spatial Patterns of Species Diversity and Phylogenetic Structure of Plant Communities in the Tianshan Mountains, Arid Central Asia

    Hong-Xiang Zhang

    2017-12-01

    Full Text Available The Tianshan Mountains, located in arid Central Asia, have a humid climate and are biodiversity hotspots. Here, we aimed to clarify whether the pattern of species diversity and the phylogenetic structure of plant communities is affected by environmental variables and glacial refugia. In this study, plant community assemblies of 17 research sites with a total of 35 sample plots were investigated at the grassland/woodland boundaries on the Tianshan Mountains. Community phylogeny of these plant communities was constructed based on two plant DNA barcode regions. The indices of phylogenetic diversity and phylogenetic community structure were calculated for these sample plots. We first estimated the correlation coefficients between species richness (SR and environmental variables as well as the presence of glacial refugia. We then mapped the significant values of indices of community phylogeny (PD, RPD, NRI, and NTI to investigate the correlation between community phylogeny and environmental structure or macrozones in the study area. The results showed that a significantly higher value of SR was obtained for the refugial groups than for the colonizing groups (P < 0.05; presence of refugia and environmental variables were highly correlated to the pattern of variation in SR. Indices of community phylogeny were not significantly different between refugial and colonizing regions. Comparison with the humid western part showed that plant communities in the arid eastern part of the Tianshan Mountains tended to display more significant phylogenetic overdispersion. The variation tendency of the PhyloSor index showed that the increase in macro-geographical and environmental distance did not influence obvious phylogenetic dissimilarities between different sample plots. In conclusion, glacial refugia and environmental factors profoundly influenced the pattern of SR, but community phylogenetic structure was not affected by glacial refugia among different plant

  8. Energy and Economic Performance of Plant-Shaded Building Façade in Hot Arid Climate

    Mahmoud Haggag

    2017-11-01

    Full Text Available The use of vegetated walls and intensive plantation around buildings has increased in popularity in hot and arid climates, such as those in the United Arab Emirates (UAE. This is due to its contribution towards reducing the heat gain and increasing the occupants’ comfort levels in spaces. This paper examines the introduction of plant-shaded walls as passive technique to reduce heat gain in indoor spaces as a strategy to lower cooling demand in hot arid climate of Al-Ain city. Experimental work was carried out to analyze the impact of using plantation for solar control of residential building façades in extreme summer. External and internal wall surface and ambient temperatures were measured for plant-shaded and bare walls. The study concluded that shading effect of the intensive plantation can reduce peak time indoor air temperature by 12 °C and reduce the internal heat gain by 2 kWh daily in the tested space. The economic analysis reveals a payback period of 10 years considering local energy tariff excluding environmental savings.

  9. Shifts in Abundance and Diversity of Soil Ammonia-Oxidizing Bacteria and Archaea Associated with Land Restoration in a Semi-Arid Ecosystem.

    Zhu Chen

    Full Text Available The Grain to Green Project (GGP is an unprecedented land restoration action in China. The project converted large areas (ca 10 million ha of steep-sloped/degraded farmland and barren land into forest and grassland resulting in ecological benefits such as a reduction in severe soil erosion. It may also affect soil microorganisms involved in ammonia oxidization, which is a key step in the global nitrogen cycle. The methods for restoration that are typically adopted in semi-arid regions include abandoning farmland and growing drought tolerant grass (Lolium perenne L. or shrubs (Caragana korshinskii Kom.. In the present study, the effects of these methods on the abundance and diversity of ammonia-oxidizing bacteria (AOB and ammonia-oxidizing archaea (AOA were evaluated via quantitative real-time PCR, terminal restriction fragment length polymorphism and clone library analysis of amoA genes. Comparisons were made between soil samples from three restored lands and the adjacent farmland in Inner Mongolia. Both the abundance and community composition of AOB were significantly different between the restored lands and the adjacent control. Significantly lower nitrification activity was observed for the restored land. Clone library analysis revealed that all AOB amoA gene sequences were affiliated with Nitrosospira. Abundance of the populations that were associated with Nitrosospira sp. Nv6 which had possibly adapted to high concentrations of inorganic nitrogen, decreased on the restored land. Only a slight difference in the AOB communities was observed between the restored land with and without the shrub (Caragana korshinskii Kom.. A minor effect of land restoration on AOA was observed. In summary, land restoration negatively affected the abundance of AOB and soil nitrification activities, suggesting the potential role of GGP in the leaching of nitrates, and in the emission of N2O in related terrestrial ecosystems.

  10. Rainfed agriculture in a semi-arid tropical climate : aspects of land- and watermanagement for red soils in India

    Huibers, F.P.

    1985-01-01

    Rainfed agriculture is defined as the production of field crops that completely depend on the local precipitation for their water supply. Although in the semi-arid tropics the mean annual precipitation might seem to be sufficient to grow (adapted) crops, its variability over the years and

  11. Ordovician ash geochemistry and the establishment of land plants

    Parnell John

    2012-08-01

    Full Text Available Abstract The colonization of the terrestrial environment by land plants transformed the planetary surface and its biota, and shifted the balance of Earth’s biomass from the subsurface towards the surface. However there was a long delay between the formation of palaeosols (soils on the land surface and the key stage of plant colonization. The record of palaeosols, and their colonization by fungi and lichens extends well back into the Precambrian. While these early soils provided a potential substrate, they were generally leached of nutrients as part of the weathering process. In contrast, volcanic ash falls provide a geochemically favourable substrate that is both nutrient-rich and has high water retention, making them good hosts to land plants. An anomalously extensive system of volcanic arcs generated unprecedented volumes of lava and volcanic ash (tuff during the Ordovician. The earliest, mid-Ordovician, records of plant spores coincide with these widespread volcanic deposits, suggesting the possibility of a genetic relationship. The ash constituted a global environment of nutrient-laden, water-saturated soil that could be exploited to maximum advantage by the evolving anchoring systems of land plants. The rapid and pervasive inoculation of modern volcanic ash by plant spores, and symbiotic nitrogen-fixing fungi, suggests that the Ordovician ash must have received a substantial load of the earliest spores and their chemistry favoured plant development. In particular, high phosphorus levels in ash were favourable to plant growth. This may have allowed photosynthesizers to diversify and enlarge, and transform the surface of the planet.

  12. SMALL HYDRO PLANTS IN LAND USE SYSTEM PLANNING IN POLAND

    Anita Bernatek

    2014-10-01

    Full Text Available Small hydropower plants are present in the land use system planning in Poland. At the national level the important role of spatial planning in the development of renewable energy was highlighted, included small hydroplants. However, it seems that at the regional level this demand has not been realized. The necessity of developing small hydroplants as a renewable energy was highlighted, but negative environmental impact was not indicated. At local level legal instrument of small hydropower plants is specified.

  13. Phytoremediation Potential of Plants Grown on Reclaimed Spoil Lands

    Post-mining reclamation is aimed at restoring the productive capacity of the disturbed land and ensuring socio-economic and environmental sustainability. Methods that have been employed for the reclamation activity are reported in the literature. This paper studied the utility of certain plant species in Ghana for remediating ...

  14. Origin and radiation of the earliest vascular land plants.

    Steemans, Philippe; Hérissé, Alain Le; Melvin, John; Miller, Merrell A; Paris, Florentin; Verniers, Jacques; Wellman, Charles H

    2009-04-17

    Colonization of the land by plants most likely occurred in a stepwise fashion starting in the Mid-Ordovician. The earliest flora of bryophyte-like plants appears to have been cosmopolitan and dominated the planet, relatively unchanged, for some 30 million years. It is represented by fossilized dispersed cryptospores and fragmentary plant remains. In the Early Silurian, cryptospore abundance and diversity diminished abruptly as trilete spores appeared, became abundant, and underwent rapid diversification. This change coincides approximately with the appearance of vascular plant megafossils and probably represents the origin and adaptive radiation of vascular plants. We have obtained a diverse trilete spore occurrence from the Late Ordovician that suggests that vascular plants originated and diversified earlier than previously hypothesized, in Gondwana, before migrating elsewhere and secondarily diversifying.

  15. Seasonal variations in plant water status of four desert halophytes from semi-arid region of Karachi

    Aziz, I.; Gul, B.; Gulzar, S.; Khan, A

    2011-01-01

    Halophytes in arid and semi arid zones of the world are often subjected to extremely variable drought, salinity and temperature. These fluctuations may bring about changes in their osmoregulation and gas exchange responses besides other physiological and biochemical processes. The purpose of this study was to detect temporal changes in plant water status and osmotic adjustment in four desert halophytes viz., Suaeda fruticosa, Heliotropium curassavicum, Haloxylon stocksii and Atriplex stocksii from an inland community at Karachi University Campus. During the dry period (November to January) water and osmotic potentials of all test species increased with higher values in A. stocksii (salt secretor) than those of S. fruticosa and H. stocksii (salt includer) and H. curassavicum (salt excluder). Proline increased substantially and was highest in H. curassavicum followed by A. stocksii in comparison to the two salt includers. The lowering of osmotic potential corresponded to an increase in Na and Cl, lower stomatal conductance and chlorophyll content indicating reduced gas exchange during the dry period. The increase in proline may have little role in osmoreglation but could contribute in scavenging reactive oxygen species. (author)

  16. Hydric soils and the relationship to plant diversity within reclaimed stream channels in semi-arid environments

    Schladweiler, B.K.; Rexroat, S.; Benson, S.

    1999-01-01

    Wetlands are especially important in semi-arid environments, such as the Powder River Basin of northeastern Wyoming, where water is a limiting factor for living organisms. Within this coal mining region of northeastern Wyoming, jurisdictional wetlands are mapped according to the US Army Corps of Engineers 1987 delineation procedure. Within the coal mining region of northeastern Wyoming, little or no full-scale mitigation or reconstruction attempts of jurisdictional wetland areas have been made until recently. Based on the importance of wetlands in a semi-arid environment and lack of information on existing or reconstructed areas, the specific objectives of the 1998 fieldwork were: (1) To define the pre-disturbance ecological state of hydric soils within jurisdictional sections of stream channels on two coal permit areas in northeastern Wyoming, and (2) To determine the effect that hydric soil parameters have on plant community distribution and composition within the two coal permit areas. Undisturbed sections of stream channels and disturbed sections of reconstructed or modified stream channels at the Rawhide Mine and Buckskin Mine, located north of Gillette, Wyoming, were selected for the study. Soils field and laboratory information and field vegetation cover were collected during 1998 within native stream channels and disturbed stream channels that had been reclaimed at each mine. Soils laboratory information is currently preliminary and included pH, electrical conductivity and sodium adsorption ratio. Results and statistical comparisons between soils and vegetation data will be presented

  17. Antecedent Moisture and Biological Inertia as Predictors of Plant and Ecosystem Productivity in Arid and Semiarid Systems

    Ogle, K.

    2011-12-01

    Many plant and ecosystem processes in arid and semiarid systems may be affected by antecedent environmental conditions (e.g., precipitation patterns, soil water availability, temperature) that integrate over past days, weeks, months, seasons, or years. However, the importance of such antecedent exogenous effects relative to conditions occurring at the time of the observed process is relatively unexplored. Even less is known about the potential importance of antecedent endogenous effects that describe the influence of past ecosystem states on the current ecosystem state; e.g., how is current ecosystem productivity related to past productivity patterns? We hypothesize that incorporation of antecedent exogenous and endogenous factors can improve our predictive understanding of many plant and ecosystem processes, especially in arid and semiarid ecosystems. Furthermore, the common approach to quantifying the effects of antecedent (exogenous) variables relies on arbitrary, deterministic definitions of antecedent variables that (1) may not accurately describe the role of antecedent conditions and (2) ignore uncertainty associated with applying deterministic definitions. In this study, we employ a stochastic framework for (1) computing the antecedent variables that estimates the relative importance of conditions experienced each time unit into the past, also providing insight into potential lag responses, and (2) estimating the effect of antecedent factors on the response variable of interest. We employ this approach to explore the potential roles of antecedent exogenous and endogenous influences in three settings that illustrate the: (1) importance of antecedent precipitation for net primary productivity in the shortgrass steppe in northern Colorado, (2) dependency of tree growth on antecedent precipitation and past growth states for pinyon growing in western Colorado, and (3) influence of antecedent soil water and prior root status on observed root growth in the Mojave

  18. Divergence and Conservative Evolution of XTNX Genes in Land Plants

    Yan-Mei Zhang

    2017-10-01

    Full Text Available The Toll-interleukin-1 receptor (TIR and Nucleotide-binding site (NBS domains are two major components of the TIR-NBS-leucine-rich repeat family plant disease resistance genes. Extensive functional and evolutionary studies have been performed on these genes; however, the characterization of a small group of genes that are composed of atypical TIR and NBS domains, namely XTNX genes, is limited. The present study investigated this specific gene family by conducting genome-wide analyses of 59 green plant genomes. A total of 143 XTNX genes were identified in 51 of the 52 land plant genomes, whereas no XTNX gene was detected in any green algae genomes, which indicated that XTNX genes originated upon emergence of land plants. Phylogenetic analysis revealed that the ancestral XTNX gene underwent two rounds of ancient duplications in land plants, which resulted in the formation of clades I/II and clades IIa/IIb successively. Although clades I and IIb have evolved conservatively in angiosperms, the motif composition difference and sequence divergence at the amino acid level suggest that functional divergence may have occurred since the separation of the two clades. In contrast, several features of the clade IIa genes, including the absence in the majority of dicots, the long branches in the tree, the frequent loss of ancestral motifs, and the loss of expression in all detected tissues of Zea mays, all suggest that the genes in this lineage might have undergone pseudogenization. This study highlights that XTNX genes are a gene family originated anciently in land plants and underwent specific conservative pattern in evolution.

  19. Rainfed agriculture in a semi-arid tropical climate : aspects of land- and watermanagement for red soils in India

    Huibers, F.P.

    1985-01-01

    Rainfed agriculture is defined as the production of field crops that completely depend on the local precipitation for their water supply. Although in the semi-arid tropics the mean annual precipitation might seem to be sufficient to grow (adapted) crops, its variability over the years and its erratic distribution over the season pose problems. During relatively dry periods, the crop might suffer from moisture stress, at other times excessive rainfall occurs, causing water logging an...

  20. Assessing the biophysical and socio-economic potential of Sustainable Land Management and Water Harvesting Technologies for rainfed agriculture across semi-arid Africa.

    Irvine, Brian; Fleskens, Luuk; Kirkby, Mike

    2016-04-01

    Stakeholders in recent EU projects identified soil erosion as the most frequent driver of land degradation in semi-arid environments. In a number of sites, historic land management and rainfall variability are recognised as contributing to the serious environmental impact. In order to consider the potential of sustainable land management and water harvesting techniques stakeholders and study sites from the projects selected and trialled both local technologies and promising technologies reported from other sites . The combined PESERA and DESMICE modelling approach considered the regional effects of the technologies in combating desertification both in environmental and socio-economical terms. Initial analysis was based on long term average climate data with the model run to equilibrium. Current analysis, primarily based on the WAHARA study sites considers rainfall variability more explicitly in time series mode. The PESERA-DESMICE approach considers the difference between a baseline scenario and a (water harvesting) technology scenario, typically, in terms of productivity, financial viability and scope for reducing erosion risk. A series of 50 year rainfall realisations are generated from observed data to capture a full range of the climatic variability. Each realisation provides a unique time-series of rainfall and through modelling can provide a simulated time-series of crop yield and erosion risk for both baseline conditions and technology scenarios. Subsequent realisations and model simulations add to an envelope of the potential crop yield and cost-benefit relations. The development of such envelopes helps express the agricultural and erosional risk associated with climate variability and the potential for conservation measures to absorb the risk, highlighting the probability of achieving a given crop yield or erosion limit. Information that can directly inform or influence the local adoption of conservation measures under the climatic variability in semi-arid

  1. Climate effects caused by land plant invasion in the Devonian

    Hir guillaume, Le; yannick, Donnadieu; yves, Goddéris; brigitte, Meyer-Berthaud; gilles, Ramstein

    2017-04-01

    Land plants invaded continents during the Mid-Paleozoic. Their spreading and diversification have been compared to the Cambrian explosion in terms of intensity and impact on the diversification of life on Earth. Whereas prior studies were focused on the evolution of the root system and its weathering contribution, here we investigated the biophysical impacts of plant colonization on the surface climate through changes in continental albedo, roughness, thermal properties, and potential evaporation using a 3D-climate model coupled to a global biogeochemical cycles associated to a simple model for vegetation dynamics adapted to Devonian conditions. From the Early to the Late Devonian, we show that continental surface changes induced by land plants and tectonic drift have produced a large CO2 drawdown without being associated to a global cooling, because the cooling trend is counteracted by a warming trend resulting from the surface albedo reduction. If CO2 is consensually assumed as the main driver of the Phanerozoic climate, during land-plant invasion, the modifications of soil properties could have played in the opposite direction of the carbon dioxide fall, hence maintaining warm temperatures during part of the Devonian.

  2. Impacts of water development on aquatic macroinvertebrates, amphibians, and plants in wetlands of a semi-arid landscape

    Euliss, Ned H.; Mushet, David M.

    2004-01-01

    We compared the macroinvertebrate and amphibian communities of 12 excavated and 12 natural wetlands in western North Dakota, USA, to assess the effects of artificially lengthened hydroperiods on the biotic communities of wetlands in this semi-arid region. Excavated wetlands were much deeper and captured greater volumes of water than natural wetlands. Most excavated wetlands maintained water throughout the study period (May to October 1999), whereas most of the natural wetlands were dry by June. Excavated wetlands were largely unvegetated or contained submergent and deep-marsh plant species. The natural wetlands had two well-defined vegetative zones populated by plant species typical of wet meadows and shallow marshes. Excavated wetlands had a richer aquatic macroinvertebrate community that included several predatory taxa not found in natural wetlands. Taxa adapted to the short hydroperiods of seasonal wetlands were largely absent from excavated wetlands. The amphibian community of natural and excavated wetlands included the boreal chorus frog (Pseudacris maculata), northern leopard frog (Rana pipiens), plains spadefoot (Scaphiopus bombifrons), Woodhouse's toad (Bufo woodhousii woodhousii), and tiger salamander (Ambystoma tigrinum). The plains spadefoot occurred only in natural wetlands while tiger salamanders occurred in all 12 excavated wetlands and only one natural wetland. Boreal chorus frogs and northern leopard frogs were present in both wetland types; however, they successfully reproduced only in wetlands lacking tiger salamanders. Artificially extending the hydroperiod of wetlands by excavation has greatly influenced the composition of native biotic communities adapted to the naturally short hydroperiods of wetlands in this semi-arid region. The compositional change of the biotic communities can be related to hydrological changes and biotic interactions, especially predation related to excavation.

  3. Land use

    Rickard, W.H.; Rogers, L.E.

    1977-01-01

    Justification for large land holdings at the Hanford Reservation has centered around a need for security and also as a buffer zone in the event of accidents. In recent years the importance of these large land holdings have become nationally recognized as highly desirable locations for ecological research concerning the function and structure of terrestrial ecosystems and as places to investigate the response of terrestrial ecosystems to long-term man-imposed environmental stresses. Carefully selected and protected land areas exist on the 110 square mile Arid Land Ecology Reserve (ALE) at Hanford. The projects described here provide supporting research for several applied projects that deal with environmental impact and land restoration. Information gained from this research has wide use and applicability to all kinds of energy technologies centered in the semi-arid shrub-steppe region of the northwestern United States. Ecological information reported includes: biotic characterization, including description of major habitats and endangered or threatened species; performances of native plant species, including determination of growth habits, nutrient requirements, and productivity; and, mineral cycling, including particularly the estimation of availability and behavior of airborne deposits to green plants

  4. Land Cover Land Use Change and Soil Organic Carbon under Climate Variability in the Semi-Arid West African Sahel (1960-2050)

    Dieye, Amadou M.

    2016-01-01

    Land Cover Land Use (LCLU) change affects land surface processes recognized to influence climate change at local, national and global levels. Soil organic carbon is a key component for the functioning of agro-ecosystems and has a direct effect on the physical, chemical and biological characteristics of the soil. The capacity to model and project…

  5. Diversity of inulinase-producing fungi associated with two Asteraceous plants, Pulicaria crispa (Forssk.) and Pluchea dioscoridis (L.) growing in an extreme arid environment

    Khalil, Doaa M. A.; Massoud, Mohamed S.; Abdelrahman, Mostafa; El-Zayat, Soad A.; El-Sayed, Magdi A.

    2018-01-01

    Inulinases are potentially valuable enzymes catalyze the hydrolysis of plant’s inulin into high fructose syrups as sweetening ingredients for food industry and ethanol production. The high demands for inulinase enzymes have promoted interest in microbial inulinases as the most suitable approach for biosynthesis of fructose syrups from inulin. Arid land ecosystem represents a valuable bioresource for soil microbial diversity with unique biochemical and physiological properties. In the present ...

  6. Planting Jatropha curcas on Constrained Land: Emission and Effects from Land Use Change

    Firdaus, M. S.; Husni, M. H. A.

    2012-01-01

    A study was carried out to assess carbon emission and carbon loss caused from land use change (LUC) of converting a wasteland into a Jatropha curcas plantation. The study was conducted for 12 months at a newly established Jatropha curcas plantation in Port Dickson, Malaysia. Assessments of soil carbon dioxide (CO2) flux, changes of soil total carbon and plant biomass loss and growth were made on the wasteland and on the established plantation to determine the effects of land preparation (i.e., tilling) and removal of the wasteland's native vegetation. Overall soil CO2 flux showed no significant difference (P Jatropha curcas to recover the biomass carbon stock lost during land conversion. As far as the present study is concerned, converting wasteland to Jatropha curcas showed no adverse effects on the loss of carbon from soil and biomass and did not exacerbate soil respiration. PMID:22545018

  7. Remote sensing monitoring of land restoration interventions in semi-arid environments with a before-after control-impact statistical design

    Meroni, Michele; Schucknecht, Anne; Fasbender, Dominique; Rembold, Felix; Fava, Francesco; Mauclaire, Margaux; Goffner, Deborah; Di Lucchio, Luisa M.; Leonardi, Ugo

    2017-07-01

    Restoration interventions to combat land degradation are carried out in arid and semi-arid areas to improve vegetation cover and land productivity. Evaluating the success of an intervention over time is challenging due to various constraints (e.g. difficult-to-access areas, lack of long-term records) and the lack of standardised and affordable methodologies. We propose a semi-automatic methodology that uses remote sensing data to provide a rapid, standardised and objective assessment of the biophysical impact, in terms of vegetation cover, of restoration interventions. The Normalised Difference Vegetation Index (NDVI) is used as a proxy for vegetation cover. Recognising that changes in vegetation cover are naturally due to environmental factors such as seasonality and inter-annual climate variability, conclusions about the success of the intervention cannot be drawn by focussing on the intervention area only. We therefore use a comparative method that analyses the temporal variations (before and after the intervention) of the NDVI of the intervention area with respect to multiple control sites that are automatically and randomly selected from a set of candidates that are similar to the intervention area. Similarity is defined in terms of class composition as derived from an ISODATA classification of the imagery before the intervention. The method provides an estimate of the magnitude and significance of the difference in greenness change between the intervention area and control areas. As a case study, the methodology is applied to 15 restoration interventions carried out in Senegal. The impact of the interventions is analysed using 250-m MODIS and 30-m Landsat data. Results show that a significant improvement in vegetation cover was detectable only in one third of the analysed interventions, which is consistent with independent qualitative assessments based on field observations and visual analysis of high resolution imagery. Rural development agencies may

  8. Changes of soil bacterial diversity as a consequence of agricultural land use in a semi-arid ecosystem.

    Guo-Chun Ding

    Full Text Available Natural scrublands in semi-arid deserts are increasingly being converted into fields. This results in losses of characteristic flora and fauna, and may also affect microbial diversity. In the present study, the long-term effect (50 years of such a transition on soil bacterial communities was explored at two sites typical of semi-arid deserts. Comparisons were made between soil samples from alfalfa fields and the adjacent scrublands by two complementary methods based on 16S rRNA gene fragments amplified from total community DNA. Denaturing gradient gel electrophoresis (DGGE analyses revealed significant effects of the transition on community composition of Bacteria, Actinobacteria, Alpha- and Betaproteobacteria at both sites. PhyloChip hybridization analysis uncovered that the transition negatively affected taxa such as Acidobacteria, Chloroflexi, Acidimicrobiales, Rubrobacterales, Deltaproteobacteria and Clostridia, while Alpha-, Beta- and Gammaproteobacteria, Bacteroidetes and Actinobacteria increased in abundance. Redundancy analysis suggested that the community composition of phyla responding to agricultural use (except for Spirochaetes correlated with soil parameters that were significantly different between the agricultural and scrubland soil. The arable soils were lower in organic matter and phosphate concentration, and higher in salinity. The variation in the bacterial community composition was higher in soils from scrubland than from agriculture, as revealed by DGGE and PhyloChip analyses, suggesting reduced beta diversity due to agricultural practices. The long-term use for agriculture resulted in profound changes in the bacterial community and physicochemical characteristics of former scrublands, which may irreversibly affect the natural soil ecosystem.

  9. Feasibility design study. Land-based OTEC plants. Final report

    Brewer, J. H.; Minor, J.; Jacobs, R.

    1979-01-01

    The purpose of this study has been to determine the feasibility of installing 10 MWe (MegaWatt-electric) and 40 MWe land-based OTEC demonstration power plants at two specific sites: Keahole Point on the western shore of the island of Hawaii; and Punta Tuna, on the southeast coast of the main island of Puerto Rico. In addition, the study has included development of design parameters, schedules and budgets for the design, construction and operation of these plants. Seawater systems (intake and discharge pipes) were to be sized so that flow losses were equivalent to those expected with a platform-based OTEC power plant. The power module (components and general arrangement was established based on the TRW design. Results are presented in detail. (WHK)

  10. Water management can reinforce plant competition in salt-affected semi-arid wetlands

    Coletti, Janaine Z.; Vogwill, Ryan; Hipsey, Matthew R.

    2017-09-01

    The diversity of vegetation in semi-arid, ephemeral wetlands is determined by niche availability and species competition, both of which are influenced by changes in water availability and salinity. Here, we hypothesise that ignoring physiological differences and competition between species when managing wetland hydrologic regimes can lead to a decrease in vegetation diversity, even when the overall wetland carrying capacity is improved. Using an ecohydrological model capable of resolving water-vegetation-salt feedbacks, we investigate why water surface and groundwater management interventions to combat vegetation decline have been more beneficial to Casuarina obesa than to Melaleuca strobophylla, the co-dominant tree species in Lake Toolibin, a salt-affected wetland in Western Australia. The simulations reveal that in trying to reduce the negative effect of salinity, the management interventions have created an environment favouring C. obesa by intensifying the climate-induced trend that the wetland has been experiencing of lower water availability and higher root-zone salinity. By testing alternative scenarios, we show that interventions that improve M. strobophylla biomass are possible by promoting hydrologic conditions that are less specific to the niche requirements of C. obesa. Modelling uncertainties were explored via a Markov Chain Monte Carlo (MCMC) algorithm. Overall, the study demonstrates the importance of including species differentiation and competition in ecohydrological models that form the basis for wetland management.

  11. Effects of plant-soil feedback on tree seedling growth under arid conditions

    Meijer, S.S.; Holmgren, M.; Putten, van der W.H.

    2011-01-01

    Aims: Plants are able to influence their growing environment by changing biotic and abiotic soil conditions. These soil conditions in turn can influence plant growth conditions, which is called plant–soil feedback. Plant–soil feedback is known to be operative in a wide variety of ecosystems ranging

  12. Soil microbial community structure is unaltered by plant invasion, vegetation clipping, and nitrogen fertilization in experimental semi-arid grasslands

    Chelsea J Carey

    2015-05-01

    Full Text Available Global and regional environmental changes often co-occur, creating complex gradients of disturbance on the landscape. Soil microbial communities are an important component of ecosystem response to environmental change, yet little is known about how microbial structure and function respond to multiple disturbances, or whether multiple environmental changes lead to unanticipated interactive effects. Our study used experimental semi-arid grassland plots in a Mediterranean-climate to determine how soil microbial communities in a seasonally variable ecosystem respond to one, two, or three simultaneous environmental changes: exotic plant invasion, plant invasion + vegetation clipping (to simulate common management practices like mowing or livestock grazing, plant invasion + nitrogen (N fertilization, and plant invasion + clipping + N fertilization. We examined microbial community structure 5-6 years after plot establishment via sequencing of >1 million 16S rRNA genes. Abiotic soil properties (soil moisture, temperature, pH, and inorganic N and microbial functioning (nitrification and denitrification potentials were also measured and showed treatment-induced shifts, including altered NO3- availability, temperature, and nitrification potential. Despite these changes, bacterial and archaeal communities showed little variation in composition and diversity across treatments. Even communities in plots exposed to three interacting environmental changes were similar to those in restored native grassland plots. Historical exposure to large seasonal and inter-annual variations in key soil properties, in addition to prior site cultivation, may select for a functionally plastic or largely dormant microbial community, resulting in a microbial community that is structurally robust to single and multiple environmental changes.

  13. Application of RAPD for molecular characterization of plant species of medicinal value from an arid environment.

    Arif, I A; Bakir, M A; Khan, H A; Al Farhan, A H; Al Homaidan, A A; Bahkali, A H; Al Sadoon, M; Shobrak, M

    2010-11-09

    The use of highly discriminatory methods for the identification and characterization of genotypes is essential for plant protection and appropriate use. We utilized the RAPD method for the genetic fingerprinting of 11 plant species of desert origin (seven with known medicinal value). Andrachne telephioides, Zilla spinosa, Caylusea hexagyna, Achillea fragrantissima, Lycium shawii, Moricandia sinaica, Rumex vesicarius, Bassia eriophora, Zygophyllum propinquum subsp migahidii, Withania somnifera, and Sonchus oleraceus were collected from various areas of Saudi Arabia. The five primers used were able to amplify the DNA from all the plant species. The amplified products of the RAPD profiles ranged from 307 to 1772 bp. A total of 164 bands were observed for 11 plant species, using five primers. The number of well-defined and major bands for a single plant species for a single primer ranged from 1 to 10. The highest pair-wise similarities (0.32) were observed between A. fragrantissima and L. shawii, when five primers were combined. The lowest similarities (0) were observed between A. telephioides and Z. spinosa; Z. spinosa and B. eriophora; B. eriophora and Z. propinquum. In conclusion, the RAPD method successfully discriminates among all the plant species, therefore providing an easy and rapid tool for identification, conservation and sustainable use of these plants.

  14. Plant species effects on soil nutrients and chemistry in arid ecological zones.

    Johnson, Brittany G; Verburg, Paul S J; Arnone, John A

    2016-09-01

    The presence of vegetation strongly influences ecosystem function by controlling the distribution and transformation of nutrients across the landscape. The magnitude of vegetation effects on soil chemistry is largely dependent on the plant species and the background soil chemical properties of the site, but has not been well quantified along vegetation transects in the Great Basin. We studied the effects of plant canopy cover on soil chemistry within five different ecological zones, subalpine, montane, pinyon-juniper, sage/Mojave transition, and desert shrub, in the Great Basin of Nevada all with similar underlying geology. Although plant species differed in their effects on soil chemistry, the desert shrubs Sarcobatus vermiculatus, Atriplex spp., Coleogyne ramosissima, and Larrea tridentata typically exerted the most influence on soil chemistry, especially amounts of K(+) and total nitrogen, beneath their canopies. However, the extent to which vegetation affected soil nutrient status in any given location was not only highly dependent on the species present, and presumably the nutrient requirements and cycling patterns of the plant species, but also on the background soil characteristics (e.g., parent material, weathering rates, leaching) where plant species occurred. The results of this study indicate that the presence or absence of a plant species, especially desert shrubs, could significantly alter soil chemistry and subsequently ecosystem biogeochemistry and function.

  15. Structure and dynamics of thylakoids in land plants

    Pribil, Mathias; Labs, Mathias; Leister, Dario

    2014-01-01

    Thylakoids of land plants have a bipartite structure, consisting of cylindrical grana stacks, made of membranous discs piled one on top of the other, and stroma lamellae which are helically wound around the cylinders. Protein complexes predominantly located in the stroma lamellae and grana end....... Depending on light conditions, thylakoid membranes undergo dynamic structural changes that involve alterations in granum diameter and height, vertical unstacking of grana, and swelling of the thylakoid lumen. This plasticity is realized predominantly by reorganization of the supramolecular structure...

  16. Three-dimensional woody vegetation structure across different land-use types and land-use intensities in a semi-arid savanna

    Fisher, J

    2009-07-01

    Full Text Available Factors influencing woody savanna vegetation structure across a land-use gradient of intensity (highly and lightly utilized communal rangeland) and type (national protected area, private game reserve and communal rangelands) were investigated. Small...

  17. Restoring abandoned agricultural lands in cold desert shrublands: Tradeoffs between water availability and invasive species

    Jeanne C. Chambers; Eric P. Eldredge; Keirith A. Snyder; David I. Board; Tara Forbis de Queiroz; Vada Hubbard

    2014-01-01

    Restoration of abandoned agricultural lands to create resilient ecosystems in arid and semi-arid ecosystems typically requires seeding or transplanting native species, improving plant-soil-water relations, and controlling invasive species. We asked if improving water relations via irrigation or surface mulch would result in negative tradeoffs between native species...

  18. The Evolution of Land Plants and the Silicate Weathering Feedback

    Ibarra, D. E.; Caves Rugenstein, J. K.; Bachan, A.; Baresch, A.; Lau, K. V.; Thomas, D.; Lee, J. E.; Boyce, C. K.; Chamberlain, C. P.

    2017-12-01

    It has long been recognized that the advent of vascular plants in the Paleozoic must have changed silicate weathering and fundamentally altered the long-term carbon cycle. Efforts to quantify these effects have been formulated in carbon cycle models that are, in part, calibrated by weathering studies of modern plant communities. In models of the long-term carbon cycle, plants play a key role in controlling atmospheric CO2, particularly in the late Paleozoic. We test the impact of some established and recent theories regarding plant-enhanced weathering by coupling a one-dimensional vapor transport model to a reactive transport model of silicate weathering. In this coupled model, we evaluate consequences of plant evolutionary innovation that have not been mechanistically incorporated into most existing models: 1) the role of evolutionary shifts in plant transpiration in enhancing silicate weathering by increasing downwind transport and recycling of water vapor to continental interiors; 2) the importance of deeply-rooted plants and their associated microbial communities in increasing soil CO2 and weathering zone length scales; and, 3) the cumulative effect of these processes. Our modeling approach is framed by energy/supply constraints calibrated for minimally vegetated-, vascular plant forested-, and angiosperm-worlds. We find that the emergence of widespread transpiration and associated inland vapor recycling approximately doubles weathering solute concentrations when deep-rooted vascular plants (Devonian-Carboniferous) fully replace a minimally vegetated (pre-Devonian) world. The later evolution of angiosperms (Cretaceous and Cenozoic) and subsequent increase in transpiration fluxes increase weathering solute concentrations by approximately an additional 20%. Our estimates of the changes in weatherability caused by land plant evolution are of a similar magnitude, but explained with new process-based mechanisms, than those used in existing carbon cycle models. We

  19. Seasonal variation in water uptake patterns of three plant species based on stable isotopes in the semi-arid Loess Plateau.

    Wang, Jian; Fu, Bojie; Lu, Nan; Zhang, Li

    2017-12-31

    Water is a limiting factor and significant driving force for ecosystem processes in arid and semi-arid areas. Knowledge of plant water uptake pattern is indispensable for understanding soil-plant interactions and species coexistence. The 'Grain for Green' project that started in 1999 in the Loess Plateau of China has led to large scale vegetation change. However, little is known about the water uptake patterns of the main plant species that inhabit in this region. In this study, the seasonal variations in water uptake patterns of three representative plant species, Stipa bungeana, Artemisia gmelinii and Vitex negundo, that are widely distributed in the semi-arid area of the Loess Plateau, were identified by using dual stable isotopes of δ 2 H and δ 18 O in plant and soil water coupled with a Bayesian mixing model MixSIAR. The soil water at the 0-120cm depth contributed 79.54±6.05% and 79.94±8.81% of the total water uptake of S. bungeana and A. gmelinii, respectively, in the growing season. The 0-40cm soil contributed the most water in July (74.20±15.20%), and the largest proportion of water (33.10±15.20%) was derived from 120-300cm soils in August for A. gmelinii. However, V. negundo obtained water predominantly from surface soil horizons (0-40cm) and then switched to deep soil layers (120-300cm) as the season progressed. This suggested that V. negundo has a greater degree of ecological plasticity as it could explore water sources from deeper soils as the water stress increased. This capacity can mainly be attributed to its functionally dimorphic root system. V. negundo may have a competitive advantage when encountering short-term drought. The ecological plasticity of plant water use needs to be considered in plant species selection and ecological management and restoration of the arid and semi-arid ecosystems in the Loess Plateau. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Vegetation structure and composition across different land use in a semi-arid savanna of southern Zimbabwe

    Zisadza-Gandiwa, P.; Mango, L.; Gandiwa, E.; Goza, D.; Parakasingwa, C.; Chinoitezvi, E.; Shimbani, J.; Muvengwi, J.

    2013-01-01

    We compared the structure and composition of vegetation communities across different land uses in the northern Gonarezhou National Park and adjacent areas, southeast Zimbabwe. Vegetation data were collected from 60 sample plots using a stratified random sampling technique from April to May 2012.

  1. Which plant traits respond to aridity? A critical step to assess functional diversity in Mediterranean drylands

    Nunes, A.; Köbel, M.; Pihno, P.; Matos, P.; de Bello, Francesco; Correia, O.; Branquinho, C.

    2017-01-01

    Roč. 239, MAY 28 2017 (2017), s. 176-184 ISSN 0168-1923 Institutional support: RVO:67985939 Keywords : Annual plants * Climatic gradient * Functional dispersion Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 3.887, year: 2016

  2. Impact of vegetation dynamics on hydrological processes in a semi-arid basin by using a land surface-hydrology coupled model

    Jiao, Yang; Lei, Huimin; Yang, Dawen; Huang, Maoyi; Liu, Dengfeng; Yuan, Xing

    2017-08-01

    Land surface models (LSMs) are widely used to understand the interactions between hydrological processes and vegetation dynamics, which is important for the attribution and prediction of regional hydrological variations. However, most LSMs have large uncertainties in their representations of ecohydrological processes due to deficiencies in hydrological parameterizations. In this study, the Community Land Model version 4 (CLM4) LSM was modified with an advanced runoff generation and flow routing scheme, resulting in a new land surface-hydrology coupled model, CLM-GBHM. Both models were implemented in the Wudinghe River Basin (WRB), which is a semi-arid basin located in the middle reaches of the Yellow River, China. Compared with CLM, CLM-GBHM increased the Nash Sutcliffe efficiency for daily river discharge simulation (1965–1969) from 0.03 to 0.23 and reduced the relative bias in water table depth simulations (2010–2012) from 32.4% to 13.4%. The CLM-GBHM simulations with static, remotely sensed and model-predicted vegetation conditions showed that the vegetation in the WRB began to recover in the 2000s due to the Grain for Green Program but had not reached the same level of vegetation cover as regions in natural eco-hydrological equilibrium. Compared with a simulation using remotely sensed vegetation cover, the simulation with a dynamic vegetation model that considers only climate-induced change showed a 10.3% increase in evapotranspiration, a 47.8% decrease in runoff, and a 62.7% and 71.3% deceleration in changing trend of the outlet river discharge before and after the year 2000, respectively. This result suggests that both natural and anthropogenic factors should be incorporated in dynamic vegetation models to better simulate the eco-hydrological cycle.

  3. Effects of land conversion from native shrub to pistachio orchard on soil erodibility in an arid region.

    Yakupoglu, Tugrul; Gundogan, Recep; Dindaroglu, Turgay; Kara, Zekeriya

    2017-10-29

    Land-use change through degrading natural vegetation for agricultural production adversely affects many of soil properties particularly organic carbon content of soils. The native shrub land and grassland of Gaziantep-Adiyaman plateau that is an important pistachio growing eco-region have been cleared to convert into pistachio orchard for the last 50 to 60 years. In this study, the effects of conversion of natural vegetation into agricultural uses on soil erodibility have been investigated. Soil samples were collected from surface of agricultural fields and adjacent natural vegetation areas, and samples were analyzed for some soil erodibility indices such as dispersion ratio (DR), erosion ratio (ER), structural stability index (SSI), Henin's instability index (I s ), and aggregate size distribution after wet sieving (AggSD). According to the statistical evaluation, these two areas were found as different from each other in terms of erosion indices except for I s index (P < 0.001 for DR and ER or P < 0.01 for SSI). In addition, native shrub land and converted land to agriculture were found different in terms of AggSD in all aggregate size groups. As a contrary to expectations, correlation tests showed that there were no any interaction between soil organic carbon and measured erodibility indices in two areas. In addition, significant relationships were determined between measured variables and soil textural fractions as statistical. These obtaining findings were attributed to changing of textural component distribution and initial aggregate size distribution results from land-use change in the study area. Study results were explained about hierarchical aggregate formation mechanism.

  4. Biodiverse planting for carbon and biodiversity on indigenous land.

    Renwick, Anna R; Robinson, Catherine J; Martin, Tara G; May, Tracey; Polglase, Phil; Possingham, Hugh P; Carwardine, Josie

    2014-01-01

    Carbon offset mechanisms have been established to mitigate climate change through changes in land management. Regulatory frameworks enable landowners and managers to generate saleable carbon credits on domestic and international markets. Identifying and managing the associated co-benefits and dis-benefits involved in the adoption of carbon offset projects is important for the projects to contribute to the broader goal of sustainable development and the provision of benefits to the local communities. So far it has been unclear how Indigenous communities can benefit from such initiatives. We provide a spatial analysis of the carbon and biodiversity potential of one offset method, planting biodiverse native vegetation, on Indigenous land across Australia. We discover significant potential for opportunities for Indigenous communities to achieve carbon sequestration and biodiversity goals through biodiverse plantings, largely in southern and eastern Australia, but the economic feasibility of these projects depend on carbon market assumptions. Our national scale cost-effectiveness analysis is critical to enable Indigenous communities to maximise the benefits available to them through participation in carbon offset schemes.

  5. Seasonal effects of irrigation on land-atmosphere latent heat, sensible heat and carbon fluxes in semi-arid basin

    Xie, Zhenghui; Zeng, Yujin

    2017-04-01

    Irrigation, which constitutes 70% of the total amount of fresh water consumed by the human population, is significantly impacting the land-atmosphere fluxes. In this study, using the improved Community Land Model version 4.5 (CLM 4.5) with an active crop model, two high resolution ( 1 km) simulations investigating the effects of irrigation on Latent Heat (LH), Sensible Heat (SH) and Carbon Fluxes (or net ecosystem exchange, NEE) from land to atmosphere on the Heihe River Basin in northwestern China were conducted using a high-quality irrigation dataset compiled from 1981 to 2013. The model output and measurements from remote sensing demonstrated the capacity and viability of the developed models to reproduce ecological and hydrological processes. The results revealed the effects of irrigation on LH and SH are strongest during summer with a LH increase of 100 W/m2 and a SH decrease of 60 W/m2 over intensely irrigated areas. However, the reactions are much weaker during spring and autumn when there is much less irrigation. When the irrigation rate below 5 mm/day, the LH generally increases, whereas the SH decreases with growing irrigation rates. However, when the irrigation threshold is in excess of 5 mm/day, there is no accrued effect of irrigation on the LH and SH. Irrigation produces opposite effects to the NEE during spring and summer. During the spring, irrigation yields more discharged carbon from the land to the atmosphere, increasing the NEE value by 0.4-0.8 gC/m2/day, while the summer irrigation favors crop fixing of carbon from atmospheric CO2, decreasing the NEE value by 0.8 gC/m2/day. The repercussions of irrigation on land-atmosphere fluxes are not solely linked to the irrigation amount, and other parameters (especially the temperature) also control the effects of irrigation on LH, SH and NEE. The study indicates that how a land surface model with high spatial resolution can represent crop growing and its effects over basin scale.

  6. Planting Jatropha curcas on Constrained Land: Emission and Effects from Land Use Change

    M. S. Firdaus

    2012-01-01

    Full Text Available A study was carried out to assess carbon emission and carbon loss caused from land use change (LUC of converting a wasteland into a Jatropha curcas plantation. The study was conducted for 12 months at a newly established Jatropha curcas plantation in Port Dickson, Malaysia. Assessments of soil carbon dioxide (CO2 flux, changes of soil total carbon and plant biomass loss and growth were made on the wasteland and on the established plantation to determine the effects of land preparation (i.e., tilling and removal of the wasteland's native vegetation. Overall soil CO2 flux showed no significant difference (<0.05 between the two plots while no significant changes (<0.05 on soil total carbon at both plots were detected. It took 1.5 years for the growth of Jatropha curcas to recover the biomass carbon stock lost during land conversion. As far as the present study is concerned, converting wasteland to Jatropha curcas showed no adverse effects on the loss of carbon from soil and biomass and did not exacerbate soil respiration.

  7. Nitrogen and plant population change radiation capture and utilization capacity of sunflower in semi-arid environment.

    Awais, Muhammad; Wajid, Aftab; Bashir, Muhammad Usman; Habib-Ur-Rahman, Muhammad; Raza, Muhammad Aown Sammar; Ahmad, Ashfaq; Saleem, Muhammad Farrukh; Hammad, Hafiz Mohkum; Mubeen, Muhammad; Saeed, Umer; Arshad, Muhammad Naveed; Fahad, Shah; Nasim, Wajid

    2017-07-01

    sunflower. High temperature during the flowering stage in 2013 shortened the crop maturity duration, which reduced the LAI, leaf area duration (LAD), crop growth rate (CGR), TDM, AY, Fi, Sa, and RUE of sunflower. Our results clearly revealed that RUE was enhanced as plant population and N application rates were increased and biomass assimilation in semi-arid environments varied with radiation capture capacity of sunflower.

  8. Atmospheric reactive nitrogen concentrations at ten sites with contrasting land use in an arid region of central Asia

    K. H. Li

    2012-10-01

    Full Text Available Atmospheric concentrations of reactive nitrogen (Nr species from 2009 to 2011 are reported for ten sites in Xinjiang, China, an arid region of central Asia. Concentrations of NH3, NO2, particulate ammonium and nitrate (pNH4+ and pNO3 showed large spatial and seasonal variation and averaged 7.71, 9.68, 1.81 and 1.13 μg N m−3, and PM10 concentrations averaged 249.2 μg m−3 across all sites. Lower NH3 concentrations and higher NO2, pNH4+ and pNO3 concentrations were found in winter, reflecting serious air pollution due to domestic heating in winter and other anthropogenic sources such as increased emissions from motor traffic and industry. The increasing order of total concentrations of Nr species was alpine grassland; desert, desert-oasis ecotone; desert in an oasis; farmland; suburban and urban ecosystems. Lower ratios of secondary particles (NH4+ and NO3 were found in the desert and desert-oasis ecotone, while urban and suburban areas had higher ratios, which implied that anthropogenic activities have greatly influenced local air quality and must be controlled.

  9. Quality and fatty acid profile of the milk of indigenous goats subjected to different local diets in Tunisian arid lands.

    Ayeb, N; Addis, M; Fiori, M; Khorchani, S; Atigui, M; Khorchani, T

    2016-02-01

    The study tested the hypothesis that certain pastoral forages and olive by-products, available in arid areas, may positively influence fatty acid composition and physicochemical properties of goat's milk. Thirty indigenous goats (body weight = 25.2 kg; age = 4.1 years) were allocated to three groups. During 60 days, the goats received ad libitum either dried olive leaves + Stipa tenacissima (group OL), khortane grass hay (group Ko) or oat hay (control diet, group OH). Milk samples were collected and analysed for total solids, fat, protein, lactose and ash content and fatty acid profile. Average milk yield did not statistically differ among groups. Milk total solids from OL group were higher in comparison with Ko and C groups (15.3, 14.7 and 14.5%, respectively; p < 0.05). Fat content was also higher for the OL group as compared to the other groups (5.44 vs. 5.01 and 4.66%, respectively, for Ko and OH). No significant differences were observed for the milk content of lactose, protein and ash. The percentage of saturated fatty acids of total milk fat was higher in OL and Ko groups compared to the C group (p < 0.001); the milk whereof was characterized by the highest percentage of monounsaturated (p < 0.01) and total unsaturated fatty acids. Milk fat of Ko and C groups showed significantly higher proportions of rumenic (CLA cis-9 trans-11) and vaccenic acids (C18:1 trans-11) compared to OL milk. The feeding system based on Stipa tenacissima and dried olive leaves resulted in the milk lowest proportion of trans-fatty acids and the highest proportion of polyunsaturated ω3-fatty acids (p < 0.05). Journal of Animal Physiology and Animal Nutrition © 2015 Blackwell Verlag GmbH.

  10. Desert farming benefits from microbial potential in arid soils and promotes diversity and plant health.

    Martina Köberl

    Full Text Available BACKGROUND: To convert deserts into arable, green landscapes is a global vision, and desert farming is a strong growing area of agriculture world-wide. However, its effect on diversity of soil microbial communities, which are responsible for important ecosystem services like plant health, is still not known. METHODOLOGY/PRINCIPAL FINDINGS: We studied the impact of long-term agriculture on desert soil in one of the most prominent examples for organic desert farming in Sekem (Egypt. Using a polyphasic methodological approach to analyse microbial communities in soil as well as associated with cultivated plants, drastic effects caused by 30 years of agriculture were detected. Analysing bacterial fingerprints, we found statistically significant differences between agricultural and native desert soil of about 60%. A pyrosequencing-based analysis of the 16S rRNA gene regions showed higher diversity in agricultural than in desert soil (Shannon diversity indices: 11.21/7.90, and displayed structural differences. The proportion of Firmicutes in field soil was significantly higher (37% than in the desert (11%. Bacillus and Paenibacillus play the key role: they represented 96% of the antagonists towards phytopathogens, and identical 16S rRNA sequences in the amplicon library and for isolates were detected. The proportion of antagonistic strains was doubled in field in comparison to desert soil (21.6%/12.4%; disease-suppressive bacteria were especially enriched in plant roots. On the opposite, several extremophilic bacterial groups, e.g., Acidimicrobium, Rubellimicrobium and Deinococcus-Thermus, disappeared from soil after agricultural use. The N-fixing Herbaspirillum group only occurred in desert soil. Soil bacterial communities were strongly driven by the a-biotic factors water supply and pH. CONCLUSIONS/SIGNIFICANCE: After long-term farming, a drastic shift in the bacterial communities in desert soil was observed. Bacterial communities in agricultural

  11. A methodology for producing small scale rural land use maps in semi-arid developing countries using orbital imagery

    Vangenderen, J. L. (Principal Investigator); Lock, B. F.

    1976-01-01

    The author has identified the following significant results. Results have shown that it is feasible to design a methodology that can provide suitable guidelines for operational production of small scale rural land use maps of semiarid developing regions from LANDSAT MSS imagery, using inexpensive and unsophisticated visual techniques. The suggested methodology provides immediate practical benefits to map makers attempting to produce land use maps in countries with limited budgets and equipment. Many preprocessing and interpretation techniques were considered, but rejected on the grounds that they were inappropriate mainly due to the high cost of imagery and/or equipment, or due to their inadequacy for use in operational projects in the developing countries. Suggested imagery and interpretation techniques, consisting of color composites and monocular magnification proved to be the simplest, fastest, and most versatile methods.

  12. Chemical composition and digestibility of some browse plant species collected from Algerian arid rangelands

    Boufennara, S.; Lopez, S.; Boussebouna, H.; Bodas, R.; Bouazza, L.

    2012-11-01

    Many wild browse and bush species are undervalued mainly because of insufficient knowledge about their potential feeding value. The objective was to evaluate some nutritional attributes of various Algerian browse and shub species (Atriplex halimus, Artemisia campestris, Artemisia herba-alba, Astragalus gombiformis, Calobota saharae, Retama raetam, Stipagrostis pungens, Lygeum spartum and Stipa tenacissima). Chemical composition, phenols and tannins concentration, in vitro digestibility, in vitro gas production kinetics and in vitro bio-assay for assessment of tannins using buffered rumen fluid, and in situ disappearence of the edible parts of the plants (leaves, thin twigs and flowers) were determined. In general, protein content in dicotyledon species was always greater than in monocotyledon grasses, these showing higher neutral and acid detergent fibre and lower lignin contents than dicots. The tannin concentrations varied considerably between species, but in general the plants investigated in this study had low tannin contents (except for Artemisia spp. and S. tenacissima). Monocots showed lower in vitro and in situ digestibilities, fermentation rate, cumulative gas production and extent of degradation than dicot species. The plants were clustered by principal components analysis in two groups: poor-quality grasses and the most digestible dicot species. Chemical composition (neutral detergent fibre and protein) and digestibility were the main influential variables determining the ranking. In conclusion, A. halimus, A. campestris, A. herba-alba and A. gombiformis can be considered of greater nutritional value than the highly fibrous and low digestible grasses (S. pungens, L. spartum and S. tenacissima) that should be considered emergency roughages. (Author) 46 refs.

  13. Biogeochemical anomaly above oil-containing structures in an arid zone. [Growth stimulation of plants by sodium naphthenate used for prospecting

    Grishchenko, O.M.

    1983-01-01

    Visual biological anomalies above the oil-containing structures are characterized by bright green coloring of the vegetation cover, gigantism of the plants, extended vegetation period of the plants, deformity of the plants, etc. Biological anomalies are associated with geological features and are observed only above the zone of fault disorders of the earth's crust, above deep faults. A conclusion is drawn about the presence above the oil-bearing structures in the arid zone of a biogeochemical anomaly whose origin is explained by the biological activity of oil and its derivatives. The petroleum growth matter is the sodium salt of naphthene acid, a growth stimulator of plants and animals. The oils of the USSR contain 0.8-4.8% naphthene acids, which effuse through the faults into the root area levels of the soil. As a result of stimulation of growth and development by the petroleum growth matter, the vegetation period of the plants is prolonged. Under the influence of natural petroleum growth substances, the height and productivity of the anomalous plants increases 2-3-fold. Formation and manifestation of signs of biogeochemical anomalies above the oil-bearing structures in the arid zone predetermine the following conditions: presence of fault disorders of the earth's crust; salinity of the root area of the soil layer necessary for neutralization of the naphthene acids with subsequent formation of the biologically active naphthenates; aridity of the desert landscape; plain relief excluding color diversity in vegetation cover because of nonuniform wetting, etc. The established biogeochemical anomaly can be used in prospecting and exploration of oil, gas and bitumen, and also in determining the fault disorders of the earth's crust.

  14. Understanding water deficit stress-induced changes in the basic metabolism of higher plants - biotechnologically and sustainably improving agriculture and the ecoenvironment in arid regions of the globe.

    Shao, Hong-Bo; Chu, Li-Ye; Jaleel, C Abdul; Manivannan, P; Panneerselvam, R; Shao, Ming-An

    2009-01-01

    Water is vital for plant growth, development and productivity. Permanent or temporary water deficit stress limits the growth and distribution of natural and artificial vegetation and the performance of cultivated plants (crops) more than any other environmental factor. Productive and sustainable agriculture necessitates growing plants (crops) in arid and semiarid regions with less input of precious resources such as fresh water. For a better understanding and rapid improvement of soil-water stress tolerance in these regions, especially in the water-wind eroded crossing region, it is very important to link physiological and biochemical studies to molecular work in genetically tractable model plants and important native plants, and further extending them to practical ecological restoration and efficient crop production. Although basic studies and practices aimed at improving soil water stress resistance and plant water use efficiency have been carried out for many years, the mechanisms involved at different scales are still not clear. Further understanding and manipulating soil-plant water relationships and soil-water stress tolerance at the scales of ecology, physiology and molecular biology can significantly improve plant productivity and environmental quality. Currently, post-genomics and metabolomics are very important in exploring anti-drought gene resources in various life forms, but modern agriculturally sustainable development must be combined with plant physiological measures in the field, on the basis of which post-genomics and metabolomics have further practical prospects. In this review, we discuss physiological and molecular insights and effects in basic plant metabolism, drought tolerance strategies under drought conditions in higher plants for sustainable agriculture and ecoenvironments in arid and semiarid areas of the world. We conclude that biological measures are the bases for the solutions to the issues relating to the different types of

  15. Soils of the Pacific Northwest shrub-steppe. Occurrence and properties of soils on the Arid Land Ecology Reserve, Hanford Reservation

    Wildung, R.E.

    1977-07-01

    The soils of the Arid Land Ecology Reserve, encompassing the IBP Grassland Biome intensive study site on the ERDA Hanford Reservation, are representative of a larger geographical region including much of the Columbia Plateau and Pacific Northwest shrub-steppe. This results from a unique diversity in parent materials of mixed origin derived from the loess eolian, lacustrine and stream-laid material including glacial outwashes, river terraces, flood plains and alluvial fans and meteorological factors accompanying a marked change in altitude within the Reserve resulting in development of soils over a range in temperature, moisture and vegetative regimes. The Reserve and the IBP Grassland Biome intensive study site serve as valuable, representative areas for the study of soil genesis and morphology in the shrub-steppe. The role of soils can be determined in basic environmental processes involving the flow of energy, cyclization of nutrients or the fate and behavior of pollutants. These processes may be examined to provide baseline information for comparison to other, more disturbed areas. Or, for investigative purposes, processes may be systematically altered to determine the influence of soil-perturbing activities such as agriculture, mining and industry on the terrestrial ecosystem

  16. Biological soil crusts: An organizing principle in dryland ecosystems (aka: the role of biocrusts in arid land hydrology)

    Chamizo, Sonia; Belnap, Jayne; Elridge, David J; Issa, Oumarou M

    2016-01-01

    Biocrusts exert a strong influence on hydrological processes in drylands by modifying numerous soil properties that affect water retention and movement in soils. Yet, their role in these processes is not clearly understood due to the large number of factors that act simultaneously and can mask the biocrust effect. The influence of biocrusts on soil hydrology depends on biocrust intrinsic characteristics such as cover, composition, and external morphology, which differ greatly among climate regimes, but also on external factors as soil type, topography and vegetation distribution patterns, as well as interactions among these factors. This chapter reviews the most recent literature published on the role of biocrusts in infiltration and runoff, soil moisture, evaporation and non-rainfall water inputs (fog, dew, water absorption), in an attempt to elucidate the key factors that explain how biocrusts affect land hydrology. In addition to the crust type and site characteristics, recent studies point to the crucial importance of the type of rainfall and the spatial scale at which biocrust effects are analyzed to understand their role in hydrological processes. Future studies need to consider the temporal and spatial scale investigated to obtain more accurate generalizations on the role of biocrusts in land hydrology.

  17. Land use suitability screening for power plant sites in Maryland

    Dobson, J.E.

    1975-01-01

    Since 1974 Oak Ridge National Laboratory (ORNL) has been engaged in developing an automated procedure for land use suitability screening. The Nuclear Regulatory Commission has funded the project to aid in the selection of power plant sites in Maryland. Its purpose is to identify candidate areas from which specific candidate sites can be chosen for detailed analyses. The ORNL approach assures that certain key variables are examined empirically for every cell in the study region before candidate sites are selected. Each variable is assigned an importance weight and compatibility score based upon its effect on the economic, social, or ecologic costs associated with construction in a given cell. The weighted scores for each variable are aggregated and output as a suitability score for each cell

  18. Greening reclamation of arid region

    Kamichika, Makio [Tottori Univ. (Japan)

    1989-01-20

    Arid regions occupy a third of the whole land in the world, and desertification in the rimland makes a problem become more acute. It is also a problem that the large part of such areas is distributed in developing countries. Desertification is defined as a phenomenon, by which the ecological system is degenerated by the change of weather conditions and the pressure of human beings and livestock, and productivity of land is markedly deteriorated. In order to prevent desertification and to promote greening reclamation and agricultural development, it is necessary to analyze desertification mechanism in detail. Artificial factors are overpopulation, too much pasturage, and conversion of grassland into farmland. Natural environmental factors are weather conditions, water resources, soil conditions, etc. It is also important for greening reclamation and development of farm land to evaluate the amount of meteorological resources (such as water resources, energy resources, etc.) and to search for the possibility of their utilization. Because of major condition to grow plants is water environment, investigation and development of water resources are important. If a project ignores the cycle of the ecological system, it might be in danger of retrogradation toward desertification. 8 refs., 10 figs., 4 tabs.

  19. Plant assemblage composition and soil P concentration differentially affect communities of AM and total fungi in a semi-arid grassland.

    Klabi, Rim; Bell, Terrence H; Hamel, Chantal; Iwaasa, Alan; Schellenberg, Mike; Raies, Aly; St-Arnaud, Marc

    2015-01-01

    Adding inorganic P- and N-fixing legumes to semi-arid grasslands can increase forage yield, but soil nutrient concentrations and plant cover may also interact to modify soil fungal populations, impacting short- and long-term forage production. We tested the effect of plant assemblage (seven native grasses, seven native grasses + the domesticated N-fixing legume Medicago sativa, seven native grasses + the native N-fixing legume Dalea purpurea or the introduced grass Bromus biebersteinii + M. sativa) and soil P concentration (addition of 0 or 200 P2O5 kg ha(-1) at sowing) on the diversity and community structure of arbuscular mycorrhizal (AM) fungi and total fungi over two consecutive years, using 454-pyrosequencing of 18S rDNA and ITS amplicons. Treatment effects were stronger in the wet year (2008) than the dry year (2009). The presence of an N-fixing legume with native grasses generally increased AM fungal diversity, while the interaction between soil P concentration and plant assemblage modified total fungal community structure in 2008. Excluding interannual variations, which are likely driven by moisture and plant productivity, AM fungal communities in semi-arid grasslands appear to be primarily affected by plant assemblage composition, while the composition of other fungi is more closely linked to soil P. © FEMS 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. Contrasting effects of land use intensity and exotic host plants on the specialization of interactions in plant-herbivore networks.

    de Araújo, Walter Santos; Vieira, Marcos Costa; Lewinsohn, Thomas M; Almeida-Neto, Mário

    2015-01-01

    Human land use tends to decrease the diversity of native plant species and facilitate the invasion and establishment of exotic ones. Such changes in land use and plant community composition usually have negative impacts on the assemblages of native herbivorous insects. Highly specialized herbivores are expected to be especially sensitive to land use intensification and the presence of exotic plant species because they are neither capable of consuming alternative plant species of the native flora nor exotic plant species. Therefore, higher levels of land use intensity might reduce the proportion of highly specialized herbivores, which ultimately would lead to changes in the specialization of interactions in plant-herbivore networks. This study investigates the community-wide effects of land use intensity on the degree of specialization of 72 plant-herbivore networks, including effects mediated by the increase in the proportion of exotic plant species. Contrary to our expectation, the net effect of land use intensity on network specialization was positive. However, this positive effect of land use intensity was partially canceled by an opposite effect of the proportion of exotic plant species on network specialization. When we analyzed networks composed exclusively of endophagous herbivores separately from those composed exclusively of exophagous herbivores, we found that only endophages showed a consistent change in network specialization at higher land use levels. Altogether, these results indicate that land use intensity is an important ecological driver of network specialization, by way of reducing the local host range of herbivore guilds with highly specialized feeding habits. However, because the effect of land use intensity is offset by an opposite effect owing to the proportion of exotic host species, the net effect of land use in a given herbivore assemblage will likely depend on the extent of the replacement of native host species with exotic ones.

  1. Richness, diversity and evenness of vegetation upon rehabilitation of gypsum mine spoiled lands in the Indian arid zone

    Kumar, S.; Sharma, K.D.; Sharma, U.K.; Gough, L.P.

    1998-01-01

    Richness, diversity and evenness of vegetation, after rehabilitation of gypsum mine spoils at Barmer were investigated in plots protected and planted one year and four years ago. There were four water harvesting treatments, viz., half-moon terraces, micro-catchments with 5% slope, ridge and furrow and control, wherein, indigenous and exotic trees and shrubs were planted at 5 ?? 5 m spacing. Sampling of the planted and natural vegetation, using quadrats and transacts, revealed much less species richness in unplanted control as compared to all treatments and in all the years. The species richness that increased initially (within one year) gradually declined over time (during four year), though the extent varied in different treatments. The water harvesting treatment showing maximum initial increase in richness also showed maximum decline over time, though decline was more in annual species. Two perennial species increased in richness with time. This was further proved from the trends in diversity and evenness indices. It was concluded that natural successional process was accelerated by rehabilitation providing stability to the habitat.

  2. Evaluation of herbicides for use in transplanting leucaena leucocephala and prosopis alba on semi-arid lands without irrigation

    Felker, P.; Smith, D.; Smith, M.; Bingham, R.L.; Reyes, I.

    1984-01-01

    Five herbicides were applied to plots at 2 rates in April 1982, and 3-month old seedlings planted 2 days later. Basal diameter was measured after 110 days and converted to dry weight using published equations. Percent weed cover was recorded 45, 75, and 105 days after planting. All herbicides increased survival over untreated controls. The greatest biomass production of both species was obtained with oryzalin treatment at 2.8 kg/ha active ingredient, which increased production 4-5X compared with control plots. Oryzalin was second to napropamide (2.24 kg/ha active ingredient) in grass control and equal to oxyfluorfen (1.12 kg/ha active ingredient) in forb control, oxyfluorfen at this rate also gave the second best biomass production. Oryzalin increased survival from 71 to 87% for Leucaena and from 81-94% for Prosopis, and is considered to be the best herbicide tested, followed by oxyfluorfen and metolachlor. Alachlor was considered to be too short-lived and napropamide too expensive.

  3. Using ISBA model for partitioning evapotranspiration into soil evaporation and plant transpiration of irrigated crops under semi-arid climate

    Aouade, Ghizlane; Jarlan, Lionel; Ezzahar, Jamal; Er-raki, Salah; Napoly, Adrien; Benkaddour, Abdelfettah; Khabba, Said; Boulet, Gilles; Chehbouni, Abdelghani; Boone, Aaron

    2016-04-01

    The Haouz region, typical of southern Mediterranean basins, is characterized by a semi-arid climate, with average annual rainfall of 250, whilst evaporative demand is about 1600 mm per year. Under these conditions, crop irrigation is inevitable for growth and development. Irrigated agriculture currently consumes the majority of total available water (up to 85%), making it critical for more efficient water use. Flood irrigation is widely practiced by the majority of the farmers (more than 85 %) with an efficiency which does not exceed 50%. In this context, a good knowledge of the partitioning of evapotranspiration (ET) into soil evaporation and plant transpiration is of crucial need for improving the irrigation scheduling and thus water use efficiency. In this study, the ISBA (Interactions Soil-Biosphere-Atmosphere) model was used for estimating ET and its partition over an olive orchard and a wheat field located near to the Marrakech City (Centre of Morocco). Two versions were evaluated: standard version which simulates a single energy balance for the soil and vegetation and the recently developed multiple energy balance (MEB) version which solves a separate energy balance for each of the two sources. Eddy covariance system, which provides the sensible and latent heat fluxes and meteorological instruments were operated during years 2003-2004 for the Olive Orchard and during years 2013 for wheat. The transpiration component was measured using a Sap flow system during summer over the wheat crop and stable isotope samples were gathered over wheat. The comparison between ET estimated by ISBA model and that measured by the Eddy covariance system showed that MEB version yielded a remarkable improvement compared to the standard version. The root mean square error (RMSE) and the correlation coefficient (R²) were about 45wm-2 and 0.8 for MEB version. By contrast, for the standard version, the RMSE and R² were about 60wm-2 and 0.7, respectively. The result also showed that

  4. Foliar δ13C Showed No Altitudinal Trend in an Arid Region and Atmospheric Pressure Exerted a Negative Effect on Plant δ13C

    Zixun Chen

    2017-07-01

    Full Text Available Previous studies have suggested foliar δ13C generally increases with altitude. However, some observations reported no changes or even decreased trends in foliar δ13C. We noted that all the studies in which δ13C increased with elevation were conducted in the human regions, whereas those investigations in which δ13C did not vary or decreased were conducted in areas with water stress. Thus, we proposed that the pattern of increasing δ13C with elevation is not a general one, and that δ13C may remain unchanged or decrease in plants grown in arid environments. To test the hypothesis, we sampled plants along altitude gradients on the shady and sunny slopes of Mount Tianshan characterized by arid and semiarid climates. The measurements of foliar δ13C showed no altitudinal trends for the plants grown on either of the slopes. Therefore, this study supported our hypothesis. In addition, the present study addressed the effect of atmospheric pressure on plant δ13C by accounting for the effects of temperature and precipitation on δ13C. This study found that the residual foliar δ13C increased with increasing altitude, suggesting that atmospheric pressure played a negative role in foliar δ13C.

  5. Differential activity of autochthonous bacteria in controlling drought stress in native Lavandula and Salvia plants species under drought conditions in natural arid soil.

    Armada, Elisabeth; Roldán, Antonio; Azcon, Rosario

    2014-02-01

    The effectiveness of autochthonous plant growth-promoting rhizobacteria was studied in Lavandula dentata and Salvia officinalis growing in a natural arid Mediterranean soil under drought conditions. These bacteria identified as Bacillus megaterium (Bm), Enterobacter sp. (E), Bacillus thuringiensis (Bt), and Bacillus sp. (Bsp). Each bacteria has different potential to meliorate water limitation and alleviating drought stress in these two plant species. B. thuringiensis promoted growth and drought avoidance in Lavandula by increasing K content, by depressing stomatal conductance, and it controlled shoot proline accumulation. This bacterial effect on increasing drought tolerance was related to the decrease of glutathione reductase (GR) and ascorbate peroxidase (APX) that resulted sensitive indexes of lower cellular oxidative damage involved in the adaptative drought response in B. thuringiensis-inoculated Lavandula plants. In contrast, in Salvia, having intrinsic lower shoot/root ratio, higher stomatal conductance and lower APX and GR activities than Lavandula, the bacterial effects on nutritional, physiological and antioxidant enzymatic systems were lower. The benefit of bacteria depended on intrinsic stress tolerance of plant involved. Lavadula demonstrated a greater benefit than Salvia to control drought stress when inoculated with B. thuringiensis. The bacterial drought tolerance assessed as survival, proline, and indolacetic acid production showed the potential of this bacteria to help plants to grow under drought conditions. B. thuringiensis may be used for Lavandula plant establishment in arid environments. Particular characteristic of the plant species as low shoot/root ratio and high stomatal conductance are important factors controlling the bacterial effectiveness improving nutritional, physiological, and metabolic plant activities.

  6. LAND JUDGING AND PLANT NUTRITION, A PROGRAMMED INSTRUCTION UNIT, REPORT NUMBER 13.

    LONG, GILBERT A.

    A UNIT OF PROGRAMED LEARNING MATERIALS WAS PRESENTED ON THE PRINCIPLES AND PROCEDURES OF LAND JUDGING AND PLANT NUTRITION. IN HIS PREPARATION, THE AUTHOR FIRST IDENTIFIED PRINCIPLES AND FACTS NECESSARY FOR EFFECTIVE LAND CLASSIFICATION AND PLANT NUTRITION BY EXAMINING RELEVANT SCIENTIFIC REPORTS. USING THIS INFORMATION, HE THEN FORMED A TEAM OF 16…

  7. Diagnosing land management and climate change impacts on snowmelt in semi-arid agricultural cold regions with an improved snowmelt model

    Harder, P.; Pomeroy, J. W.; Helgason, W.

    2017-12-01

    Spring snowmelt is the most important hydrological event in semi-arid agricultural cold regions, recharging soil moisture and generating the majority of annual runoff. Adoption of no-till agricultural practices means vast areas of the Canadian Prairies, and other analogous regions, are characterized by standing crop stubble. The emergence of stubble during snowmelt will have important implications for the snowpack energy balance. In addition, spatiotemporally dynamic snowcover heterogeneity leads to enhancement of turbulent flux contributions to melt by advection of energy from warm moist bare ground to snow. Stubble emergence and advection are generally unaccounted for in snow models. To address these challenges a stubble-snow-atmosphere surface energy balance model is developed that relates stubble parameters to the snow surface energy balance. Existing fractal understandings of snowcover geometry are applied to a conceptualized boundary layer integration model to estimate a sensible and latent heat advection efficiency. The small-scale nature of stubble-snow-atmosphere interactions makes direct validation of the energy balance terms challenging. However, the energy balance estimates are assessed by comparing to measured snow and stubble surface temperatures, snow surface incoming shortwave radiation and areal average turbulent fluxes. Advection estimates are validated from a two-dimensional air temperature, water vapor and windspeed profiles. Snowcover geometry relationships are validated/updated with unmanned air vehicle observations. Observations for model assessment occurred in 2015 and 2016 on wheat and canola stubble fields in north-central Saskatchewan, Canada. The model is not calibrated to melt rates, yet compares well with available observations, providing confidence in the model structure and parameterization. Sensitivity analysis using the model revealed compensatory relationships in energy balance terms resulting in limited reduction of energy

  8. Effects of land use and climate change on ecosystem services in Central Asia's arid regions: A case study in Altay Prefecture, China.

    Fu, Qi; Li, Bo; Hou, Ying; Bi, Xu; Zhang, Xinshi

    2017-12-31

    The sustainable use of ecosystem services (ES) can contribute to enhancing human well-being. Understanding the effects of land use and climate change on ES can provide scientific and targeted guidance for the sustainable use of ES. The objective of this study was to reveal the way in which land use and climate change influence the spatial and temporal variations of ES in the mountain-oasis-desert system (MODS). In this study, we assessed water yield, soil conservation, crop production, and sand fixation in 1990, 2000, and 2010 in Altay Prefecture, which is representative of the MODS, based on widely used biophysical models. Moreover, we analyzed the effects of different land use and climate change conditions on ES. The results show that the area of forest and bare land decreased in Altay Prefecture. In contrast, the area of grassland with low coverage and cropland increased. The climate of this area presented an overall warming-wetting trend, with warming-drying and cooling-wetting phenomena in some areas. Soil conservation in the mountain zone, water yield in the oasis zone, and sand fixation in the desert zone all decreased under the influence of land use change alone. The warming-drying trend led to decreased water yield in the oasis zone and increased wind erosion in the desert zone. Based on the results, we recommend that local governments achieve sustainable use of ES by planting grasslands with high coverage in the oasis zone, increasing investment in agricultural science and technology, and establishing protected areas in the mountain and desert zones. The methodology in our study can also be applied to other regions with a MODS structure. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Modeling of hydrological processes in arid agricultural regions

    Jiang LI,Xiaomin MAO,Shaozhong KANG,David A. BARRY

    2015-12-01

    Full Text Available Understanding of hydrological processes, including consideration of interactions between vegetation growth and water transfer in the root zone, underpins efficient use of water resources in arid-zone agriculture. Water transfers take place in the soil-plant-atmosphere continuum, and include groundwater dynamics, unsaturated zone flow, evaporation/transpiration from vegetated/bare soil and surface water, agricultural canal/surface water flow and seepage, and well pumping. Models can be categorized into three classes: (1 regional distributed hydrological models with various land uses, (2 groundwater-soil-plant-atmosphere continuum models that neglect lateral water fluxes, and (3 coupled models with groundwater flow and unsaturated zone water dynamics. This review highlights, in addition, future research challenges in modeling arid-zone agricultural systems, e.g., to effectively assimilate data from remote sensing, and to fully reflect climate change effects at various model scales.

  10. The potential for SLM, facing human constraints, the case of the semi-arid agro-pastoral lands in the Atlantic plateaus, Morocco

    Laouina, A.; Chaker, M.; Aderghal, M.; Machouri, N.; Alkarkouri, J.

    2012-04-01

    inside the fragile environments, vulnerable to degradation by runoff and erosion. These scenarios try to integrate the concept of SLM into the current system of livestock to make this system, progressively evolve towards intensification, more income and less land degradation. The proposed changes are not easy to apply. At first, at the level of the farms, we must consider the private character of property, the dispersion of the plots and the various state and forms of degradation. At the level of the whole territory, many agro-sylvo-pastoral combinations are possible. But, in what measure is this vision practicable? Can we recommend a specialization of certain lands in grazing and others in farming, without rethinking the restructuring of the fragmented plots? This calls agreements between farmers and new landowners, coming from the city. The choice for planting gullied plots with atriplex demonstrated, during 2 years of monitoring, its effective potential for land rehabilitation, fodder supply of the cattle and for evolution towards a new semi-intensive breeding. But, how to encourage the farmers to invest in this effort of planting? What would become the role of the domanial forest, which would be in this perspective, less used for grazing and devoted for new activities?

  11. Predicting germination in semi-arid wildland seedbeds II. Field validation of wet thermal-time models

    Jennifer K. Rawlins; Bruce A. Roundy; Dennis Eggett; Nathan. Cline

    2011-01-01

    Accurate prediction of germination for species used for semi-arid land revegetation would support selection of plant materials for specific climatic conditions and sites. Wet thermal-time models predict germination time by summing progress toward germination subpopulation percentages as a function of temperature across intermittent wet periods or within singular wet...

  12. Natural genetic variation in stomatal response can help to increase acclimation of plants to dried environments

    Aliniaeifard, S.; Meeteren, Van U.

    2018-01-01

    In the current century, global warming is becoming an alarming issue causing an increase in the area of barren lands. Arid and semi-arid regions are characterised with shortage of water in both under- and above-ground environments. Plants with high water use efficiency should be considered for

  13. Shallow land burial technology - ARID

    Abeele, W.V.; DePoorter, G.L.; Hakonson, T.E.; Nyhan, J.W.

    1983-01-01

    Scope of the tasks being performed by Los Alamos will be identified. Emphasis will be placed upon the geotechnical work. Important geotechnical properties of a low-level waste disposal site include hydraulic conductivity consolidation, and shear strength of the applicable medium. The hydraulic conductivity of crushed Bandelier tuff has been assessed using the instantaneous profile method. The best fit of hydraulic conductivity as a function of water content was found to be a power function. The coefficient of consolidation was difficult to measure because of the relatively high hydraulic conductivity. The repose angle for crushed tuff is higher than the normally expected range. This is probably because of a higher than average angularity and surface roughness. The high coefficient of consolidation and high internal friction angle make finely crushed tuff a material with ideal mechanical characteristics. The drawback is that a high coefficient of consolidation is linked to a high hydraulic conductivity

  14. Land Use Requirements of Modern Wind Power Plants in the United States

    Denholm, P.; Hand, M.; Jackson, M.; Ong, S.

    2009-08-01

    This report provides data and analysis of the land use associated with modern, large wind power plants (defined as greater than 20 megawatts (MW) and constructed after 2000). The analysis discusses standard land-use metrics as established in the life-cycle assessment literature, and then discusses their applicability to wind power plants. The report identifies two major 'classes' of wind plant land use: 1) direct impact (i.e., disturbed land due to physical infrastructure development), and 2) total area (i.e., land associated with the complete wind plant project). The analysis also provides data for each of these classes, derived from project applications, environmental impact statements, and other sources. It attempts to identify relationships among land use, wind plant configuration, and geography. The analysts evaluated 172 existing or proposed projects, which represents more than 26 GW of capacity. In addition to providing land-use data and summary statistics, they identify several limitations to the existing wind project area data sets, and suggest additional analysis that could aid in evaluating actual land use and impacts associated with deployment of wind energy.

  15. Evaluation of Seed and Forage Yield of Perennial Plants with Low Water Requirement in Abandoned Farming Lands

    Ali gazanchian

    2017-10-01

    Full Text Available Introduction Drought is a natural phenomenon in arid and semi-arid regions of the world. It is created by low precipitation, high evaporation and reduced soil moisture. Today, they are the major threats to agricultural lands due to fluctuations in rainfall, limited water resources, wells salinization and subsequently abandoned farming lands. Iran is located on the world's dry belt and more than 90 percent of its area is located in the arid and semi-arid climatic regions. It has been reported that the annual rate of soil erosion is up to 33 tons per hectare and 5 to 6 times more than the standard limit. Also, 90% of the country's protein production comes from animals sources. Due to the lack of adequate forage production, the main burden of protein production is imposed on the natural resources and pastures. Therefore, In order to enhance soil stabilization and maintain its fertility, optimum use of off-season precipitations, preventing the flow of water and protecting the abandoned farming lands from the flood risk, increasing the water permeability in the soil, and helping to feed the underwater aquifers and finally the production of forage and seeds, the development of perennial plants cultivation is an important conservative practice. The aim of this study is to emphasize on the selection of the best perennial forage species with low water requirements and acceptable performance for renovation of the abandoned farming lands and moving towards sustainable agriculture approaches. Materials and Methods In this experiment, 10 species of perennial grasses (Agropyron elongatum Host., Secale montanum Guss., Festuca arundinaceae Schreb., Dactylis glomerata L., Agropyron intermedium Host., Agropyron repense L., Agropyron cristatum L., Panicum antidutale Retz., Bromus inermis Leyss., Bromus riparius Rehmann, Agropyron cristatum L. and two legumes includes Trifolium pratense L., Onobrychis sativa Lam. were studied at Asatan-e-Ghods Razavi farm in

  16. A regional field-based assessment of organic C sequestration and GHG balances in irrigated agriculture in Mediterranean semi-arid land

    Virto, Inigo; Antón, Rodrigo; Arias, Nerea; Orcaray, Luis; Enrique, Alberto; Bescansa, Paloma

    2016-04-01

    In a context of global change and increasing food demand, agriculture faces the challenge of ensuring food security making a sustainable use of resources, especially arable land and water. This implies in many areas a transition towards agricultural systems with increased and stable productivity and a more efficient use of inputs. The introduction of irrigation is, within this framework, a widespread strategy. However, the C cycle and the net GHG emissions can be significantly affected by irrigation. The net effect of this change needs to be quantified at a regional scale. In the region of Navarra (NE Spain) more than 22,300 ha of rainfed agricultural land have been converted to irrigation in the last years, adding to the previous existing irrigated area of 70,000 ha. In this framework the project Life+ Regadiox (LIFE12 ENV/ES/000426, http://life-regadiox.es/) has the objective of evaluating the net GHG balances and atmospheric CO2 fixation rates of different management strategies in irrigated agriculture in the region. The project involved the identification of areas representative of the different pedocllimatic conditions in the region. This required soil and climate characterizations, and the design of a network of agricultural fields representative of the most common dryland and irrigation managements in these areas. This was done from available public datasets on climate and soil, and from soil pits especially sampled for this study. Two areas were then delimited, mostly based on their degree of aridity. Within each of those areas, fields were selected to allow for comparisons at three levels: (i) dryland vs irrigation, (ii) soil and crop management systems for non-permanent crops, and (iii) soil management strategies for permanent crops (namely olive orchards and vineyards). In a second step, the objective of this work was to quantify net SOC variations and GHG balances corresponding to the different managements identified in the previous step. These

  17. Diversity dynamics of silurian-early carboniferous land plants in South china.

    Conghui Xiong

    Full Text Available New megafossil and microfossil data indicate four episodes in the diversification of Silurian-Early Carboniferous land plants of South China, a relatively continuous regional record. Plant diversity increased throughout, but the rising curve was punctuated by three major falls. There were peaks of origination in the Ludlow-Pragian, Givetian, late Famennian and Visean and peaks of extinction in the Pragian-Emsian, Givetian and early Tournaisian. Speciation and extinction rates were highest in the Lochkovian-Pragian and became progressively lower in subsequent stages. High correlation coefficients indicate that these events are associated with the availability of land habitat contingent on eustatic variations and increasing numbers of cosmopolitan genera. Meanwhile, proportions of endemic genera declined gradually. Due to less endemism and more migrations, both speciation and species extinction rates reduced. The changes of diversity and the timing of the three extinctions of land plants in South China are similar to those known already from Laurussia. However, the largest events in the Lochkovian-Pragian and subsequent smaller ones have not been seen in the global pattern of plant evolution. These land plant events do not correspond well temporally with those affecting land vertebrates or marine invertebrates. In South China, the diversity curve of land plants is generally opposite to that of marine faunas, showing a strong effect of eustatic variations. The increasing diversity of both land vertebrates and plants was punctuated above the Devonian-Carboniferous boundary, known as Romer's Gap, implying common underlying constraints on macroevolution of land animals and plants.

  18. Evaluating rainwater harvesting systems in arid and semi-arid regions

    Ammar, Adham Ali

    2017-01-01

    Rainwater harvesting (RWH) is an ancient traditional technology practised in many parts of the world, especially in arid and semi-arid regions (ASARs). ASARs represent 40% of the earth’s land surface and are characterised by low average annual rainfall and uneven temporal and spatial

  19. A study to explore the use of orbital remote sensing to determine native arid plant distribution. [Arizona Regional Ecological Test Site

    Mcginnies, W. G. (Principal Investigator); Lepley, L. K.; Haase, E. F.; Conn, J. S.; Musick, H. B.; Foster, K. E.

    1974-01-01

    The author has identified the following significant results. It is possible to determine, from ERTS imagery, native arid plant distribution. Using techniques of multispectral masking and extensive fieldwork, three native vegetation communities were defined and mapped in the Avra Valley study area. A map was made of the Yuma area with the aid of ground truth correlations between areas of desert pavement visible on ERTS images and unique vegetation types. With the exception of the Yuma soil-vegetation correlation phenomena, only very gross differentiations of desert vegetation communities can be made from ERTS data. Vegetation communities with obvious vegetation density differences such as saguaro-paloverde, creosote bush, and riparian vegetation can be separated on the Avra Valley imagery while more similar communities such as creosote bush and saltbush could not be differentiated. It is suggested that large differences in vegetation density are needed before the signatures of two different vegetation types can be differentiated on ERTS imagery. This is due to the relatively insignificant contribution of vegetation to the total radiometric signature of a given desert scene. Where more detailed information concerning the vegetation of arid regions is required, large scale imagery is appropriate.

  20. Genome Size Diversity and Its Impact on the Evolution of Land Plants

    Jaume Pellicer

    2018-02-01

    Full Text Available Genome size is a biodiversity trait that shows staggering diversity across eukaryotes, varying over 64,000-fold. Of all major taxonomic groups, land plants stand out due to their staggering genome size diversity, ranging ca. 2400-fold. As our understanding of the implications and significance of this remarkable genome size diversity in land plants grows, it is becoming increasingly evident that this trait plays not only an important role in shaping the evolution of plant genomes, but also in influencing plant community assemblages at the ecosystem level. Recent advances and improvements in novel sequencing technologies, as well as analytical tools, make it possible to gain critical insights into the genomic and epigenetic mechanisms underpinning genome size changes. In this review we provide an overview of our current understanding of genome size diversity across the different land plant groups, its implications on the biology of the genome and what future directions need to be addressed to fill key knowledge gaps.

  1. Utilization of saline water and land: Reclaiming lost resources

    Naqvi, Mujtaba

    2001-01-01

    There is an abundance of saline water on the globe. Large tracts of land are arid and/or salt-affected, and a large number of plant species are known to be salt-tolerant. It would seem obvious that salt tolerant plants (halophytes) have a role in utilizing the two wasted resources, saline water and wastelands. We will briefly describe how these resources can be fruitfully utilized and how the IAEA has helped several countries to demonstrate the possibility of cultivating salt tolerant plant species on arid saline wastelands for economic and environmental benefit. After some brief introductory remarks we will discuss the results of the project

  2. Total and bioavailable arsenic concentration in arid soils and its uptake by native plants from the pre-Andean zones in Chile.

    Díaz, O; Tapia, Y; Pastene, R; Montes, S; Núñez, N; Vélez, D; Montoro, R

    2011-06-01

    Arsenic is the most important contaminant of the environment in northern Chile. Soil samples and plant organs from three native plant species, Pluchea absinthioides, Atriplex atacamensis and Lupinus microcarpus, were collected from arid zones in order to determine the total and bioavailable arsenic concentrations in soils and to assess the bioconcentration factor (BCF) and transport index (Ti) of arsenic in the plants. Total arsenic concentrations in soils (pH 8.3-8.5) where A. atacamensis and P. absinthioides were collected, reached levels considered to be contaminated (54.3 ± 15.4 and 52.9 ± 9.9 mg kg⁻¹, respectively), and these values were approximately ten times higher than in soils (pH 7.6) where L. microcarpus was collected. Bioavailable arsenic ranged from 0.18 to 0.42% of total arsenic concentration. In the three plant species, arsenic concentration in leaves were significantly (p ≤ 0.05) higher than in roots. L. microcarpus showed the highest arsenic concentration in its leaves (9.7 ± 1.6 mg kg⁻¹) and higher values of BCF (1.8) and Ti (6.1), indicating that this species has a greater capacity to accumulate and translocate the metalloid to the leaf than do the other species.

  3. Evidence for land plant cell wall biosynthetic mechanisms in charophyte green algae

    Mikkelsen, Maria Dalgaard; Harholt, Jesper; Ulvskov, Peter

    2014-01-01

    in CGA is currently unknown, as no genomes are available, so this study sought to give insight into the evolution of the biosynthetic machinery of CGA through an analysis of available transcriptomes. METHODS: Available CGA transcriptomes were mined for cell wall biosynthesis GTs and compared with GTs...... to colonize land. These cell walls provide support and protection, are a source of signalling molecules, and provide developmental cues for cell differentiation and elongation. The cell wall of land plants is a highly complex fibre composite, characterized by cellulose cross-linked by non......-cellulosic polysaccharides, such as xyloglucan, embedded in a matrix of pectic polysaccharides. How the land plant cell wall evolved is currently unknown: early-divergent chlorophyte and prasinophyte algae genomes contain a low number of glycosyl transferases (GTs), while land plants contain hundreds. The number of GTs...

  4. Cultural plant harvests on federal lands: perspectives from members of the Northwest Native American Basketweavers Association

    Rebecca Dobkins; Ceara Lewis; Susan Hummel; Emily. Dickey

    2016-01-01

    Native Americans who wish to harvest forest plants for traditional uses report difficulties gaining access to federal lands in the northwestern United States. To learn more about this issue, we reviewed the published literature on site access and resource harvests by tribal members and discussed it with Native American traditional users of plant resources. Specifically...

  5. Topical radiation protection questions of use of agricultural land in the environs of nuclear power plants

    Carach, J.; Csupka, S.; Petrasova, M.

    1982-01-01

    A survey is presented of the problems of the use of agricultural land in the environs of nuclear power plants. The analysis of emission activity in nuclear power plants presently under construction shows that for normal operation no precautions are necessary. For accidents, specific health protection measures are planned. (author)

  6. Disturbance by an endemic rodent in an arid shrubland is a habitat filter: effects on plant invasion and taxonomical, functional and phylogenetic community structure.

    Escobedo, Víctor M; Rios, Rodrigo S; Salgado-Luarte, Cristian; Stotz, Gisela C; Gianoli, Ernesto

    2017-03-01

    Disturbance often drives plant invasion and may modify community assembly. However, little is known about how these modifications of community patterns occur in terms of taxonomic, functional and phylogenetic structure. This study evaluated in an arid shrubland the influence of disturbance by an endemic rodent on community functional divergence and phylogenetic structure as well as on plant invasion. It was expected that disturbance would operate as a habitat filter favouring exotic species with short life cycles. Sixteen plots were sampled along a disturbance gradient caused by the endemic fossorial rodent Spalacopus cyanus , measuring community parameters and estimating functional divergence for life history traits (functional dispersion index) and the relative contribution to functional divergence of exotic and native species. The phylogenetic signal (Pagel's lambda) and phylogenetic community structure (mean phylogenetic distance and mean nearest taxon phylogenetic distance) were also estimated. The use of a continuous approach to the disturbance gradient allowed the identification of non-linear relationships between disturbance and community parameters. The relationship between disturbance and both species richness and abundance was positive for exotic species and negative for native species. Disturbance modified community composition, and exotic species were associated with more disturbed sites. Disturbance increased trait convergence, which resulted in phylogenetic clustering because traits showed a significant phylogenetic signal. The relative contribution of exotic species to functional divergence increased, while that of natives decreased, with disturbance. Exotic and native species were not phylogenetically distinct. Disturbance by rodents in this arid shrubland constitutes a habitat filter over phylogeny-dependent life history traits, leading to phylogenetic clustering, and drives invasion by favouring species with short life cycles. Results can be

  7. Land degradation and halophytic plant diversity of milleyha wetland ecosystem (samandag-hatay), Turkey

    Altay, V.

    2012-01-01

    Investigations were undertaken during 2010-2011 to study effect of human induced land degradation on structure of some halophytic plant communities. Over all 183 taxa of vascular plant were recorded. Out of these 76 were of typical halophytes. The dominant plant taxa were; Phragmites australis, Halimione portulacoides and Bolboschoenus maritimus. The threatened categories of these taxa were identified from the Red Data Book of Turkey together with their distribution. The impact of degradation on the habitats due to land use for agriculture, organic and inorganic waste disposal and housing for tourisitc purposes were identified and conservation measures were outlined in this study. (author)

  8. URJC GB dataset: Community-based seed bank of Mediterranean high-mountain and semi-arid plant species at Universidad Rey Juan Carlos (Spain).

    Alonso, Patricia; Iriondo, José María

    2014-01-01

    The Germplasm Bank of Universidad Rey Juan Carlos was created in 2008 and currently holds 235 accessions and 96 species. This bank focuses on the conservation of wild-plant communities and aims to conserve ex situ a representative sample of the plant biodiversity present in a habitat, emphasizing priority ecosystems identified by the Habitats Directive. It is also used to store plant material for research and teaching purposes. The collection consists of three subcollections, two representative of typical habitats in the center of the Iberian Peninsula: high-mountain pastures (psicroxerophylous pastures) and semi-arid habitats (gypsophylic steppes), and a third representative of the genus Lupinus. The high-mountain subcollection currently holds 153 accessions (63 species), the semi-arid subcollection has 76 accessions (29 species,) and the Lupinus subcollection has 6 accessions (4 species). All accessions are stored in a freezer at -18 °C in Kilner jars with silica gel. The Germplasm Bank of Universidad Rey Juan Carlos follows a quality control protocol which describes the workflow performed with seeds from seed collection to storage. All collectors are members of research groups with great experience in species identification. Herbarium specimens associated with seed accessions are preserved and 63% of the records have been georreferenced with GPS and radio points. The dataset provides unique information concerning the location of populations of plant species that form part of the psicroxerophylous pastures and gypsophylic steppes of Central Spain as well as populations of genus Lupinus in the Iberian Peninsula. It also provides relevant information concerning mean seed weight and seed germination values under specific incubation conditions. This dataset has already been used by researchers of the Area of Biodiversity and Conservation of URJC as a source of information for the design and implementation of experimental designs in these plant communities. Since

  9. URJC GB dataset: Community-based seed bank of Mediterranean high-mountain and semi-arid plant species at Universidad Rey Juan Carlos (Spain

    Patricia Alonso

    2014-03-01

    Full Text Available The Germplasm Bank of Universidad Rey Juan Carlos was created in 2008 and currently holds 235 accessions and 96 species. This bank focuses on the conservation of wild-plant communities and aims to conserve ex situ a representative sample of the plant biodiversity present in a habitat, emphasizing priority ecosystems identified by the Habitats Directive. It is also used to store plant material for research and teaching purposes. The collection consists of three subcollections, two representative of typical habitats in the center of the Iberian Peninsula: high-mountain pastures (psicroxerophylous pastures and semi-arid habitats (gypsophylic steppes, and a third representative of the genus Lupinus. The high-mountain subcollection currently holds 153 accessions (63 species, the semi-arid subcollection has 76 accessions (29 species, and the Lupinus subcollection has 6 accessions (4 species. All accessions are stored in a freezer at -18 °C in Kilner jars with silica gel. The Germplasm Bank of Universidad Rey Juan Carlos follows a quality control protocol which describes the workflow performed with seeds from seed collection to storage. All collectors are members of research groups with great experience in species identification. Herbarium specimens associated with seed accessions are preserved and 63% of the records have been georreferenced with GPS and radio points. The dataset provides unique information concerning the location of populations of plant species that form part of the psicroxerophylous pastures and gypsophylic steppes of Central Spain as well as populations of genus Lupinus in the Iberian Peninsula. It also provides relevant information concerning mean seed weight and seed germination values under specific incubation conditions. This dataset has already been used by researchers of the Area of Biodiversity and Conservation of URJC as a source of information for the design and implementation of experimental designs in these plant

  10. Local health practices and the knowledge of medicinal plants in a Brazilian semi-arid region: environmental benefits to human health.

    Zank, Sofia; Peroni, Nivaldo; de Araújo, Elcida Lima; Hanazaki, Natalia

    2015-02-23

    The concept of eco-cultural health considers the dynamic interaction between humans and ecosystems, emphasizing the implications of the health of the ecosystem for the health and well-being of human populations. Ethnobotanical studies focusing on folk medicine and medicinal plants can contribute to the field of eco-cultural health if they incorporate the perspective and local knowledge of communities. We investigated the local health practices in three rural communities living within the vicinity of a protected area of sustainable use in a semi-arid region of Brazil. We analyzed the opinions of local health experts on the elements that influence human health and on how the environment contributes to this influence. We also analyzed and compared the local knowledge of medicinal plants, as knowledge of this type is an important factor when considering the interaction between environmental and human health. We performed structured interviews and free-listings with 66 local health experts. We used content analysis to systematize the elements of the influences on human health. We compared the richness of the plants cited among communities and analyzed the differences among the three communities regarding the ways in which the plants were obtained and the environments in which plants were collected. The local experts identified several influences of the environment on human health. These influences can be associated with ecosystem services, such as climatic conditions, water and air quality, recreation and medicinal and food resources. We identified 192 medicinal plant species, most of which were gathered from wild ecosystems. The most important environments for the three communities were the plateau mountain and backyards. The informants had a broad and integrated view of health, perceiving the importance of conserving the environment within the National Forest of Araripe for the health and well-being of the local populations.

  11. Mycorrhizal association between the desert truffle Terfezia boudieri and Helianthemum sessiliflorum alters plant physiology and fitness to arid conditions.

    Turgeman, Tidhar; Ben Asher, Jiftach; Roth-Bejerano, Nurit; Kagan-Zur, Varda; Kapulnik, Yoram; Sitrit, Yaron

    2011-10-01

    The host plant Helianthemum sessiliflorum was inoculated with the mycorrhizal desert truffle Terfezia boudieri Chatin, and the subsequent effects of the ectomycorrhizal relationship on host physiology were determined. Diurnal measurements revealed that mycorrhizal (M) plants had higher rates of photosynthesis (35%), transpiration (18%), and night respiration (49%) than non-mycorrhizal (NM) plants. Consequently, M plants exhibited higher biomass accumulation, higher shoot-to-root ratios, and improved water use efficiency compared to NM plants. Total chlorophyll content was higher in M plants, and the ratio between chlorophyll a to chlorophyll b was altered in M plants. The increase in chlorophyll b content was significantly higher than the increase in chlorophyll a content (2.58- and 1.52-fold, respectively) compared to control. Calculation of the photosynthetic activation energy indicated lower energy requirements for CO(2) assimilation in M plants than in NM plants (48.62 and 61.56 kJ mol(-1), respectively). Continuous measurements of CO(2) exchange and transpiration in M plants versus NM plants provided a complete picture of the daily physiological differences brought on by the ectomycorrhizal relationships. The enhanced competence of M plants to withstand the harsh environmental conditions of the desert is discussed in view of the mycorrhizal-derived alterations in host physiology. © Springer-Verlag 2011

  12. Land use and habitat conditions across the southwestern Wyoming sagebrush steppe: development impacts, management effectiveness and the distribution of invasive plants

    Manier, Daniel J.; Aldridge, Cameron L.; Anderson, Patrick; Chong, Geneva; Homer, Collin G.; O'Donnell, Michael S.; Schell, Spencer

    2011-01-01

    For the past several years, USGS has taken a multi-faceted approach to investigating the condition and trends in sagebrush steppe ecosystems. This recent effort builds upon decades of work in semi-arid ecosystems providing a specific, applied focus on the cumulative impacts of expanding human activities across these landscapes. Here, we discuss several on-going projects contributing to these efforts: (1) mapping and monitoring the distribution and condition of shrub steppe communities with local detail at a regional scale, (2) assessing the relationships between specific, land-use features (for example, roads, transmission lines, industrial pads) and invasive plants, including their potential (environmentally defined) distribution across the region, and (3) monitoring the effects of habitat treatments on the ecosystem, including wildlife use and invasive plant abundance. This research is focused on the northern sagebrush steppe, primarily in Wyoming, but also extending into Montana, Colorado, Utah and Idaho. The study area includes a range of sagebrush types (including, Artemisia tridentata ssp. tridentata, Artemisia tridentata ssp. wyomingensis, Artemisia tridentata ssp. vaseyana, Artemisia nova) and other semi-arid shrubland types (for example, Sarcobatus vermiculatus, Atriplex confertifolia, Atriplex gardneri), impacted by extensive interface between steppe ecosystems and industrial energy activities resulting in a revealing multiple-variable analysis. We use a combination of remote sensing (AWiFS (1 Any reference to platforms, data sources, equipment, software, patented or trade-marked methods is for information purposes only. It does not represent endorsement of the U.S.D.I., U.S.G.S. or the authors), Landsat and Quickbird platforms), Geographic Information System (GIS) design and data management, and field-based, replicated sampling to generate multiple scales of data representing the distribution of shrub communities for the habitat inventory. Invasive plant

  13. Drought-Tolerant Plant Growth-Promoting Rhizobacteria Associated with Foxtail Millet in a Semi-arid Agroecosystem and Their Potential in Alleviating Drought Stress

    Xuguang Niu

    2018-01-01

    Full Text Available The application of plant growth promoting rhizobacteria (PGPR to agro-ecosystems is considered to have the potential for improving plant growth in extreme environments featured by water shortage. Herein, we isolated bacterial strains from foxtail millet (Setaria italica L., a drought-tolerant crop cultivated in semiarid regions in the northeast of China. Four isolates were initially selected for their ability to produce ACC deaminase as well as drought tolerance. The isolates were identified as Pseudomonas fluorescens, Enterobacter hormaechei, and Pseudomonas migulae on the basis of 16S rRNA sequence analysis. All of these drought-tolerant isolates were able to produce EPS (exopolysaccharide. Inoculation with these strains stimulated seed germination and seedling growth under drought stress. Pseudomonas fluorescens DR7 showed the highest level of ACC deaminase and EPS-producing activity. DR7 could efficiently colonize the root adhering soil, increased soil moisture, and enhance the root adhering soil/root tissue ratio. These results suggest drought tolerant PGPR from foxtail millet could enhance plant growth under drought stress conditions and serve as effective bioinoculants to sustain agricultural production in arid regions.

  14. Environmental impacts of in-house windrow composting of broiler litter prior to land application in subtropical/semi-arid conditions

    Land application to crop and pasture land is a common and effective method of utilizing the resource value of poultry litter. In-house windrow composting of litter is an emerging management practice with the potential to mitigate water quality and nuisance odor concerns associated with land applica...

  15. Land

    C.A. Hunsberger (Carol); Tom P. Evans

    2012-01-01

    textabstractPressure on land resources has increased during recent years despite international goals to improve their management. The fourth Global Environment Outlook (UNEP 2007) highlighted the unprecedented land-use changes created by a burgeoning population, economic development and

  16. Reductions of plant cover induced by sheep grazing change the above-belowground partition and chemistry of organic C stocks in arid rangelands of Patagonian Monte, Argentina.

    Larreguy, C; Carrera, A L; Bertiller, M B

    2017-09-01

    The objective of this study was to estimate the size and chemical quality of the total organic C stock and its partition between above-belowground plant parts and soil at sites with different plant cover induced by sheep grazing in the arid Patagonian Monte. This study was conducted at six representative sites with increasing signs of canopy disturbance attributed to grazing pressure. We used faeces density as a proxy of grazing pressure at each site. We assessed the total plant cover, shrub and perennial grass cover, total standing aboveground biomass (AGB), litter mass and belowground biomass (BGB) at each site. We further estimated the content of organic C, lignin and soluble phenols in plant compartments and the content of organic C, organic C in humic substances (recalcitrant C) and water soluble C (labile C) in soil at each site. Total plant cover was significantly related to grazing pressure. Standing AGB and litter mass decreased with increasing canopy disturbance while BGB did not vary across sites. Total organic C stock and the organic C stock in standing AGB increased with increasing total plant, shrub, and perennial grass cover. The organic C stock in litter mass increased with increasing total plant and shrub cover, while the organic C stock in BGB did not vary across sites. Lignin content in plant compartments increased with increasing total and shrub cover, while soluble phenols content did not change across sites. The organic C stock and the water soluble C content in soil were positively associated with perennial grass cover. Changes in total plant cover induced by grazing pressure negatively affected the size of the total organic C stock, having minor impact on the size of belowground than aboveground components. The reduction of perennial grass cover was reflected in decreasing chemical quality of the organic C stock in soil. Accordingly, plant managerial strategies should not only be focused on the amount of organic C sequestered but also on the

  17. Gardens on the Arid Climate

    Eka Saputra, Weldy

    2017-12-01

    Bahrain is located in the climate of the arid zone which rainfall is low and irregular. This paper discusses the approaches which response to the local context that has been implemented by the government of Bahrain to sustain the quality of the public garden in the arid climate, turning to green. Generally, the approach is an improvement in the central treatment of waste water system plant that used to irrigate the landscaping, agriculture as well as for industry use. These approaches are not the only technologically, but also involves the participation of community to achieve sustainable garden in this country.

  18. Hierarchy of responses to resource pulses in arid and semi-arid ecosystems.

    Schwinning, Susanne; Sala, Osvaldo E

    2004-10-01

    In arid/semi-arid ecosystems, biological resources, such as water, soil nutrients, and plant biomass, typically go through periods of high and low abundance. Short periods of high resource abundance are usually triggered by rainfall events, which, despite of the overall scarcity of rain, can saturate the resource demand of some biological processes for a time. This review develops the idea that there exists a hierarchy of soil moisture pulse events with a corresponding hierarchy of ecological responses, such that small pulses only trigger a small number of relatively minor ecological events, and larger pulses trigger a more inclusive set and some larger ecological events. This framework hinges on the observation that many biological state changes, where organisms transition from a state of lower to higher physiological activity, require a minimal triggering event size. Response thresholds are often determined by the ability of organisms to utilize soil moisture pulses of different infiltration depth or duration. For example, brief, shallow pulses can only affect surface dwelling organisms with fast response times and high tolerance for low resource levels, such as some species of the soil micro-fauna and -flora, while it takes more water and deeper infiltration to affect the physiology, growth or reproduction of higher plants. This review first discusses how precipitation, climate and site factors translate into soil moisture pulses of varying magnitude and duration. Next, the idea of the response hierarchy for ecosystem processes is developed, followed by an exploration of the possible evolutionary background for the existence of response thresholds to resource pulses. The review concludes with an outlook on global change: does the hierarchical view of precipitation effects in ecosystems provide new perspectives on the future of arid/semiarid lands?

  19. Land-Use Requirements for Solar Power Plants in the United States

    Ong, S.; Campbell, C.; Denholm, P.; Margolis, R.; Heath, G.

    2013-06-01

    This report provides data and analysis of the land use associated with utility-scale ground-mounted solar facilities, defined as installations greater than 1 MW. We begin by discussing standard land-use metrics as established in the life-cycle assessment literature and then discuss their applicability to solar power plants. We present total and direct land-use results for various solar technologies and system configurations, on both a capacity and an electricity-generation basis. The total area corresponds to all land enclosed by the site boundary. The direct area comprises land directly occupied by solar arrays, access roads, substations, service buildings, and other infrastructure. As of the third quarter of 2012, the solar projects we analyze represent 72% of installed and under-construction utility-scale PV and CSP capacity in the United States.

  20. effect of plant density and land race on the growth

    COMPUTER UNIT

    Key words: optimum plant density sweet potato landraces and yield. ..... From this work it can be seen that improved management practices play a role in obtaining ... 22.2. 24.7. 21.4. 22.2. SED D. 5.23. 6.15. SED V. 5.23. 6.15. SED D xV. 10.46.

  1. Phytoremediation Potential of Plants Grown on Reclaimed Spoil Lands

    Michael

    2016-06-01

    Jun 1, 2016 ... leaves of the plant species were analysed for heavy metal accumulation. ... Bioremediation, Contaminated Soils, Degraded Soils, Heavy Metal .... contaminant and prevents migration to groundwater and air ..... “Determination of mobile heavy metal fraction ... sludge,” Communications in Soil Science and.

  2. Simulation of Sediment Yield in a Semi-Arid River Basin under Changing Land Use: An Integrated Approach of Hydrologic Modelling and Principal Component Analysis

    Charles Gyamfi

    2016-11-01

    Full Text Available Intensified human activities over the past decades have culminated in the prevalence of dire environmental consequences of sediment yield resulting mainly from land use changes. Understanding the role that land use changes play in the dynamics of sediment yield would greatly enhance decision-making processes related to land use and water resources management. In this study, we investigated the impacts of land use and cover changes on sediment yield dynamics through an integrated approach of hydrologic modelling and principal component analysis (PCA. A three-phase land use scenario (2000, 2007 and 2013 employing the “fix-changing” method was used to simulate the sediment yield of the Olifants Basin. Contributions in the changes in individual land uses to sediment yield were assessed using the component and pattern matrixes of PCA. Our results indicate that sediment yield dynamics in the study area is significantly attributed to the changes in agriculture, urban and forested lands. Changes in agriculture and urban lands were directly proportional to sediment yield dynamics of the Olifants Basin. On the contrary, forested areas had a negative relationship with sediment yield indicating less sediment yield from these areas. The output of this research work provides a simplistic approach of evaluating the impacts of land use changes on sediment yield. The tools and methods used are relevant for policy directions on land and water resources planning and management.

  3. Deep Percolation in Arid Piedmont Slopes: Multiple Lines of Evidence Show How Land Use Change and Ecohydrological Properties Affect Groundwater Recharge

    Schreiner-McGraw, A.; Vivoni, E. R.; Browning, D. M.

    2017-12-01

    A critical hydrologic process in arid regions is the contribution of episodic streamflow in ephemeral channels to groundwater recharge. This process has traditionally been studied in channels that drain large watersheds (10s to 100s km2). In this study, we aim to characterize the provision of the ecosystem services of surface and groundwater supply in a first-order watershed (4.6 ha) in an arid piedmont slope of the Jornada Experimental Range (JER). We use an observational and modeling approach to estimate deep percolation. During a 6 year study period, we observed 428 mm of percolation (P) and 39 mm of runoff (Q); ratios of P to rainfall (R) of P/R = 0.27 and Q/R = 0.02. Utilizing an instrument network and site measurements, we determine that percolation occurs primarily inside channel reaches when these receive runoff from upland hillslopes and find that a monthly rainfall threshold of 62 mm is needed for significant percolation to be generated. In order to quantify the mechanisms leading to this threshold response, we develop a channel transmission loss module for the TIN-based Real-time Integrated Basin Simulator (tRIBS) and test the model thoroughly against the available observations over the study period. For these purposes, we make use of image classifications from Unmanned Aerial Vehicle flights, a ground-based phenocam, and species-level measurements to parameterize vegetation processes in the model. We then conduct an extensive set of sensitivity experiments to determine the relative roles of channel, soil, and vegetation properties on modifying the relation between monthly rainfall and percolation. Additionally, we test how the observed vegetation transitions in the JER over the last 150 years affect the deep percolation and runoff estimates. By quantifying mechanisms through which vegetation changes affect water resource provision, this work provides new insights on the ecohydrological controls on the water yield of arid piedmont slopes.

  4. Land-Use Mapping in a Mixed Urban-Agricultural Arid Landscape Using Object-Based Image Analysis: A Case Study from Maricopa, Arizona

    Christopher S. Galletti

    2014-06-01

    Full Text Available Land-use mapping is critical for global change research. In Central Arizona, U.S.A., the spatial distribution of land use is important for sustainable land management decisions. The objective of this study was to create a land-use map that serves as a model for the city of Maricopa, an expanding urban region in the Sun Corridor of Arizona. We use object-based image analysis to map six land-use types from ASTER imagery, and then compare this with two per-pixel classifications. Our results show that a single segmentation, combined with intermediary classifications and merging, morphing, and growing image-objects, can lead to an accurate land-use map that is capable of utilizing both spatial and spectral information. We also employ a moving-window diversity assessment to help with analysis and improve post-classification modifications.

  5. Is annual recharge coefficient a valid concept in arid and semi-arid regions?

    Y. Cheng

    2017-10-01

    Full Text Available Deep soil recharge (DSR (at depth greater than 200 cm is an important part of water circulation in arid and semi-arid regions. Quantitative monitoring of DSR is of great importance to assess water resources and to study water balance in arid and semi-arid regions. This study used a typical bare land on the eastern margin of Mu Us Sandy Land in the Ordos Basin of China as an example to illustrate a new lysimeter method of measuring DSR to examine if the annual recharge coefficient is valid or not in the study site, where the annual recharge efficient is the ratio of annual DSR over annual total precipitation. Positioning monitoring was done on precipitation and DSR measurements underneath mobile sand dunes from 2013 to 2015 in the study area. Results showed that use of an annual recharge coefficient for estimating DSR in bare sand land in arid and semi-arid regions is questionable and could lead to considerable errors. It appeared that DSR in those regions was influenced by precipitation pattern and was closely correlated with spontaneous strong precipitation events (with precipitation greater than 10 mm other than the total precipitation. This study showed that as much as 42 % of precipitation in a single strong precipitation event can be transformed into DSR. During the observation period, the maximum annual DSR could make up 24.33 % of the annual precipitation. This study provided a reliable method of estimating DSR in sandy areas of arid and semi-arid regions, which is valuable for managing groundwater resources and ecological restoration in those regions. It also provided strong evidence that the annual recharge coefficient was invalid for calculating DSR in arid and semi-arid regions. This study shows that DSR is closely related to the strong precipitation events, rather than to the average annual precipitation, as well as the precipitation patterns.

  6. Pathways of primary CO2 fixation in C-4 plants of the family chenopodiaceae from the arid zone of central Asia

    P'yankov, V.I.; Vakhrusheva, D.V.

    1991-01-01

    The authors determined the kinetics of 14 C incorporation after a 10-sec gulp of 14 CO 2 to study formation of primary photosynthetic products in 35 C-4 species of the family chenopodiaceae in the desert zone of central Asia. Representatives of the main life forms of desert plants with various types of anatomical structure of the assimilating organs (salsoloid, kochioid, atriplercoid, and suaedoid groups) were among the studied species. It was demonstrated that the ratio of pathways of formation of C-4 acids (malate and aspartate) depends upon the structural type affiliation and the ecological conditions of the habitat. Plants of the suaedoid and atriplecoid groups (which usually dwell under conditions of salination) exhibit the aspartate NAD-malic enzyme (NAD-ME) type of C-4 photosynthesis. The malate and aspartate types of metabolism are detected in species of the kochioid group. All biochemical variants (NADP-ME, NAD-ME, and mixed) are represented in the salsoloid group. Psammophilous species of this group have the malate type of acid metabolism, whereas halophilic species have the aspartate type. Quantitative criteria are proposed for referring C-4 plants to the NAD- and NADP-ME types on the basis of formation of primary products. It is demonstrated that the role of the aspartate pathway of CO 2 transfer in plants increases in proportion to worsening of ecological conditions of the habitat. The evolutionary sequence of metabolic systems was formed in the C-3-NAD-ME-NADP-ME direction, the origin of the C-4 syndrome having been associated with colonization of arid territories, especially saline localities

  7. Use of alternative plant resources by common marmosets (Callithrix jacchus) in the semi-arid caatinga scrub forests of northeastern Brazil.

    Amora, Tacyana Duarte; Beltrão-Mendes, Raone; Ferrari, Stephen F

    2013-04-01

    The common marmoset (Callithrix jacchus) is amply distributed in the Brazilian Northeast, but little is known of its ecology in the semi-arid Caatinga scrublands. The present study provides the first detailed data on the composition of the diet of C. jacchus in Caatinga ecosystems, derived from observations at four sites in the state of Sergipe. While exudate sources were gouged at all four sites in a manner typical of the species, fruit was the principal component of the diet at the main study site during most months, and a number of unusual items were eaten, including leaves, and the reproductive parts of cacti and bromeliads. These plants are rarely recorded in marmoset diets, but are common in caatinga habitats. Leaves were ingested during 5 of the 8 months monitored at the main study site, reaching 39.74% of the diet in 1 month, and appeared to be an alternative fallback food to plant exudates during periods when fruit was scarce. Three species of cactus provided both flowers and fruits, while the terrestrial bromeliad, Encholirium spectabile, provided nectar (30.81% of the diet in November). Approximately half of the plant species (and three families) identified in this study had not been recorded previously in the diet of Callithrix. Overall, the data suggest that, while the marmosets exploit the same types of plant foods in the Caatinga, the resource base is quite distinct from that of the Atlantic Forest. Other differences, such as relatively small groups and large home ranges, may contribute to divergent ecological patterns, which require more systematic investigation. Am. J. Primatol. 75:333-341, 2013. © 2012 Wiley Periodicals, Inc. © 2012 Wiley Periodicals, Inc.

  8. A five-Stage Socio-Economic Change Model of the Impact of Resettlement Policy on Human Welfare in Semi-Arid Lands of Kenya: A Case Study of Muuni Community in Makueni District

    Gitunu, A.M.M.

    2002-01-01

    This paper discusses relocation stress experienced by an agro-pastoral community of Makueni district during eviction from their former settlement areas thus causing the untold socio-cultural and economic suffering during eviction, transitional, shifting and resettlement stages. The relocation involved three communities formerly settled in Chyulu hills in Makueni district, Kalembwani in Kajiado district and Kibwezi township in Makueni district whose occupation was agro-pastoral production. The relocation was involuntary and unplanned and had adversely disrupted their food-security, socio-cultural and economic welfare. The study of the Muuni community spanned a period of over three years (1996 - 1999). The '5-stage socio-economic change model' studied in this study shows the ensuring adjustment process most likely to be experienced when top-down policy decisions are taken and how this affects farming communities within semi-arid lands of Kenya where involuntary and unplanned resettlement of people takes place

  9. Phylogenetic evidence for cladogenetic polyploidization in land plants.

    Zhan, Shing H; Drori, Michal; Goldberg, Emma E; Otto, Sarah P; Mayrose, Itay

    2016-07-01

    Polyploidization is a common and recurring phenomenon in plants and is often thought to be a mechanism of "instant speciation". Whether polyploidization is associated with the formation of new species (cladogenesis) or simply occurs over time within a lineage (anagenesis), however, has never been assessed systematically. We tested this hypothesis using phylogenetic and karyotypic information from 235 plant genera (mostly angiosperms). We first constructed a large database of combined sequence and chromosome number data sets using an automated procedure. We then applied likelihood models (ClaSSE) that estimate the degree of synchronization between polyploidization and speciation events in maximum likelihood and Bayesian frameworks. Our maximum likelihood analysis indicated that 35 genera supported a model that includes cladogenetic transitions over a model with only anagenetic transitions, whereas three genera supported a model that incorporates anagenetic transitions over one with only cladogenetic transitions. Furthermore, the Bayesian analysis supported a preponderance of cladogenetic change in four genera but did not support a preponderance of anagenetic change in any genus. Overall, these phylogenetic analyses provide the first broad confirmation that polyploidization is temporally associated with speciation events, suggesting that it is indeed a major speciation mechanism in plants, at least in some genera. © 2016 Botanical Society of America.

  10. Jojoba - a promising plant for the semi-arid regions. [North America, plants, seeds, oils, waxes, growth, cultivation, lubricants, guayule, mesquite

    Yermanos, D.M.

    1979-01-01

    As a result of the world-wide concern for conservation of resources and for the development of new renewable resources a great deal of attention has been directed towards the development of jojoba as a potential new crop for semi-arid regions. Jojoba grows wild in the Southwestern U.S. and N. Mexico, in areas where the annual precipitation is 4''-15''. Under cultivation it appears to grow satisfactorily in areas of marginal soil fertility, high salinity and high atmospheric temperatures. It appears to have no major natural enemies and to be tolerant to chemical treatments, if they were to become necessary. It is perennial with an assumed life span in excess of 150 years. Jojoba seed has an average weight of about 0.5 grams per seed, and it contains a unique liquid wax which is a superior lubricant and a potential replacement of whale oil, obtained from the sperm whale, and endangered species. Thus, jojoba has a double appeal, first as a potential crop of semi-arid regions requiring low cultural and energy inputs and second as a source of a valuable commodity. It should be pointed out that a cheap and abundant source of lubricants will disappear when our stock of fossil fuels are exhausted and that none of our new sources of energy have lubricants as by-products. Finally, jojoba could be grown with other companion crops such as guayule or mesquite for more diversified farming.

  11. Plant protection under conditions of radioactive contamination of agricultural lands

    Filipas, A.S.; Oulianenko, L.N.; Pimenov, E.P.

    1995-01-01

    Increasing influence of anthropogenic contaminants as well as substantiated risk of the action of ionizing radiation on agroecosystems suggest the necessity of studying both the state of separate components of cenosis and search for methods on retention of ecosystem stability as a whole. In this case it should be taken into account that by retention of resistance of living organisms to the action of stress agents not only genetically conditioned potential but induction of protective reactions at the expense of ecogene action is of deciding significance as well. Protection of agricultural plants on the territories subjected to radioactive contamination resulting from the ChNPP accident brings attention of research works to a series of problems, the main one being the minimization of pesticide use by the total ecologization of technological processes, in plant growing. But an ordinary discontinuance of conducting protective chemical measures leads to growth in the number of harmful organisms in crop sowings and as a consequence an increase of crop loss and decrease of its quality. It is possible to solve this problem by introduction of measures increasing the resistance of agricultural plants to the action of unfavorable factors of environment. Application of biologically active substances (BAS) of natural and synthetic nature for incrustation of seeds fits into these methods. For the territories with increased content of radionuclides and especially by their rehabilitation the methods of preventive treatments directed to retarding the development of harmful organisms in crop sowings and excluding subsequent technological operations on chemical protection of sowings takes on special significance as it is directly connected with the problem of radiation burden on workers of agroindustrial complex

  12. Impacts of Rainfall and Land Use on Sediment Regime in a Semi-Arid Region: Case Study of the Wuqi Catchment in the Upper Beiluo River Basin, China

    Zhu, J.; Gao, P.; Geissen, V.; Maroulis, J.; Ritsema, C.J.; Mu, X.; Zhao, G.

    2015-01-01

    The middle reaches of the Yellow River Basin transport the vast majority of sediment (>85% of the basin's total available sediment load), which has had profound effects on the characteristics of the middle and lower reaches of the Yellow River. With recent land use and land cover change, the

  13. Legacy effects of no-analogue disturbances alter plant community diversity and composition in semi-arid sagebrush steppe

    Ripplinger, Julie; Franklin, Janet; Edwards, Thomas C.

    2015-01-01

    Questions(i) What role does the type of managed disturbance play in structuring sagebrush steppe plant communities? (ii) How does the composition of post-disturbance plant communities change with time since disturbance? (iii) Does plant community diversity change over time following managed disturbance?LocationField study within the sagebrush steppe ecosystem. Rich County, Utah, USA.MethodsWe developed a chronosequence spanning up to 50 yrs post-treatment to study sagebrush steppe vegetation dynamics. Direct ordination was used to examine plant community composition by managed disturbance type and time since disturbance, and factorial analysis of covariance was used to examine diversity dynamics following disturbance. Indicator species values were calculated in order to identify characteristic species for each disturbance type.ResultsPlant communities experienced a shift toward distinct community composition for each of the three managed disturbance types, and gave no indication of returning to untreated community composition or diversity. Small post-disturbance increases in the number of non-native grass species were observed in the treatments relative to reference, with native forb species making the largest contribution to altered composition. On fire- and chemically-treated sites the proportional native forb species richness increased over time since disturbance, while the proportional contribution of non-native forbs to total species richness decreased. For all three treatment types, native grasses contributed less on average to total richness than on reference sites, while non-native grasses made up a higher proportion of total richness.ConclusionsCommon shrubland management techniques have legacy effects on the composition and diversity of sagebrush steppe plant communities, and no-analogue disturbances, such as chemical or mechanical treatments, have more pronounced legacy effects than treatments similar to natural disturbance regimes (fire). This study

  14. lands

    A.T. O'Geen

    2015-04-01

    Full Text Available Groundwater pumping chronically exceeds natural recharge in many agricultural regions in California. A common method of recharging groundwater — when surface water is available — is to deliberately flood an open area, allowing water to percolate into an aquifer. However, open land suitable for this type of recharge is scarce. Flooding agricultural land during fallow or dormant periods has the potential to increase groundwater recharge substantially, but this approach has not been well studied. Using data on soils, topography and crop type, we developed a spatially explicit index of the suitability for groundwater recharge of land in all agricultural regions in California. We identified 3.6 million acres of agricultural land statewide as having Excellent or Good potential for groundwater recharge. The index provides preliminary guidance about the locations where groundwater recharge on agricultural land is likely to be feasible. A variety of institutional, infrastructure and other issues must also be addressed before this practice can be implemented widely.

  15. Photosynthesis of green algal soil crust lichens from arid lands in southern Utah, USA: Role of water content on light and temperature responses of CO2 exchange

    Lange, Otto L.; Belnap, Jayne; Meyer, Angelika

    1997-01-01

    Biotic soil crusts are a worldwide phenomenon in arid and semi-arid landscapes. Metabolic activity of the poikilohydric organisms found in these crusts is dominated by quick and drastic changes in moisture availability and long periods of drought. Under controlled conditions, we studied the role of water content on photosynthetic and respiratory CO2 exchange of three green algal soil crust lichens from a desert site in southern Utah (USA): Diploschistes diacapsis (Ach.) Lumbsch, Psora cerebriformis W. Weber, and Squamarina lentigera (Weber) Poelt.Photosynthetic metabolism is activated by extremely small amounts of moisture; lower compensation values for net photosynthesis (NP) are reached between 0.05 and 0.27 mm of precipitation equivalent. Thus, the lichens can use very low degrees of hydration for carbon gain. Maximal NP occurs between 0.39 and 0.94 mm precipitation equivalent, and area-related rates equal 2.6–5.2 μmol CO2 m−2s−1. All three tested species show ‘sun plant’ features, including high light requirements for CO2 exchange compensation and for NP saturation.Diploschistes diacapsis maintains high rates of NP at full water saturation. In contrast, suprasaturated thalli of the other two species show a strong depression in NP which can be removed or reduced by increased external CO2 concentration. Consequently, this depression is most probably caused by increased thallus diffusive resistances due to pathway blockage by water. This depression will greatly limit carbon gain of these species in the field after heavy rain. It occurs at all temperatures of ecological relevance and also under conditions of low light. However, maximum water holding capacity of P. cerebriformis and S. lentigera is higher than that of D. diacapsis. This could mean that periods of hydration favorable for metabolic activity for those two species last longer than those of D. diacapsis. This might compensate for their lower rates of NP during suprasaturation. Thus, two

  16. Potential of medicinal plants from the Brazilian semi-arid region (Caatinga) against Staphylococcus epidermidis planktonic and biofilm lifestyles.

    Trentin, Danielle da Silva; Giordani, Raquel Brandt; Zimmer, Karine Rigon; da Silva, Alexandre Gomes; da Silva, Márcia Vanusa; Correia, Maria Tereza Dos Santos; Baumvol, Israel Jacob Rabin; Macedo, Alexandre José

    2011-09-01

    Medicinal plants from the Caatinga, a Brazilian xeric shrubland, are used in folk medicine to treat infections. These ethnopharmacological data can contribute to obtaining new antimicrobial/antibiofilm extracts and natural product prototypes for the development of new drugs. The aim of this study was to investigate the antibiofilm and antibacterial activities of 45 aqueous extracts from 24 Caatinga plant species. The effect of aqueous extracts on planktonic cells and on biofilm formation by Staphylococcus epidermidis was studied by the OD(600) absorbance and by the crystal violet assay, respectively. Scanning electron microscopy (SEM) was used to generate comparative images of extract-treated and untreated biofilms. Chromatographic analyses were performed to characterize the active extracts. The in vitro screening, at 0.4 mg/mL and 4.0mg/mL, showed 20 plants effective in preventing biofilm formation and 13 plants able to inhibit planktonic bacterial growth. SEM images demonstrated distinct profiles of bacterial adhesion, matrix production and cell morphology according to different treatments and surfaces. The phytochemical analysis of the selected active extracts indicates the polyphenols, coumarins, steroids and terpenes as possible active compounds. This study describes the first antibiofilm and antibacterial screening of Caatinga plants against S. epidermidis. The evaluation presented in this study confirms several ethnopharmacological reports and can be utilized to identify new antibiofilm and antibacterial products against S. epidermidis from traditional Brazilian medicine. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  17. Effect of Plant Density and Land Race on the Growth and Yield of ...

    Field study was conducted at National Root Crops Research Institute out station Nyanya Research farm located at Zhewun Jidna Nasarawa State during 2007 and 2008 cropping seasons. The aim was to determine the effect of optimum plant population Density of sweet potato land races under improved management ...

  18. Management of plant communities on set-aside land and its effects on earthworm communities

    Gormsen, D.; Hedlund, K.; Korthals, G. W.; Mortimer, S. R.; Pižl, Václav; Šmilauerová, M.; Sugg, E.

    2004-01-01

    Roč. 40, 3-4 (2004), s. 123-128 ISSN 1164-5563 Grant - others:Evropská unie(XE) ENV4-CT95-0002 Keywords : earthworm community * plant community * land use Subject RIV: EH - Ecology, Behaviour Impact factor: 0.776, year: 2004

  19. Risk-based design of process plants with regard to domino effects and land use planning.

    Khakzad, Nima; Reniers, Genserik

    2015-12-15

    Land use planning (LUP) as an effective and crucial safety measure has widely been employed by safety experts and decision makers to mitigate off-site risks posed by major accidents. Accordingly, the concept of LUP in chemical plants has traditionally been considered from two perspectives: (i) land developments around existing chemical plants considering potential off-site risks posed by major accidents and (ii) development of existing chemical plants considering nearby land developments and the level of additional off-site risks the land developments would be exposed to. However, the attempts made to design chemical plants with regard to LUP requirements have been few, most of which have neglected the role of domino effects in risk analysis of major accidents. To overcome the limitations of previous work, first, we developed a Bayesian network methodology to calculate both on-site and off-site risks of major accidents while taking domino effects into account. Second, we combined the results of risk analysis with Analytic Hierarchical Process to design an optimal layout for which the levels of on-site and off-site risks would be minimum. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. On the Growth and Detectability of Land Plants on Habitable Planets around M Dwarfs.

    Cui, Duo; Tian, Feng; Wang, Yuwei; Li, Changshen; Yu, Chaoqing; Yu, Le

    2017-12-01

    One signature of life on Earth is the vegetation red edge (VRE) feature of land plants, a dramatic change of reflectivity at wavelength near 0.7 μm. Potentially habitable planets around M dwarfs are tidally locked, which can limit the distribution of land plants. In this study, we used a biogeochemical model to investigate the distribution of land plants on potentially habitable planets around M dwarfs driven by climate data produced in a general circulation model (GCM). When considering the effects of clouds, the observation time needed for VRE detection on nearby p = 1 exoplanets around nearby M dwarfs is on the order of days using a 25 m 2 telescope if a large continent faces Earth during observations. For p = 1.5 exoplanets, the detection time could be similar if land plants developed the capability to endure a dark/cold environment for extended periods of time and the continent configuration favors observations. Our analysis suggests that hypothetical exovegetation VRE features are easier to detect than Earth vegetation and that VRE detection is possible for nearby exoplanets even under cloudy conditions. Key Words: Vegetation red edge-Exoplanets-M dwarfs-Biosignature detection. Astrobiology 17, 1219-1232.

  1. The late Paleozoic ecological-evolutionary laboratory, a land-plant fossil record perspective

    Looy, Cindy; Kerp, Hans; Duijnstee, Ivo; DiMichele, Bill

    2014-01-01

    In this essay we examine the fossil record of land plants, focusing on the late Paleozoic. We explore the nature of this record in terms of what is preserved, where, why and with what biases. And as a consequence, how it can be used to answer questions posed at various spatial and temporal scales,

  2. Projecting trends in plant invasions in Europe under different scenarios of future land-use change

    Chytrý, M.; Wild, Jan; Pyšek, Petr; Jarošík, Vojtěch; Dendoncker, N.; Reginster, I.; Pino, J.; Maskell, L. C.; Vila, M.; Pergl, Jan; Kühn, I.; Spangenberg, J.H.; Settele, J.

    2012-01-01

    Roč. 21, č. 1 (2012), s. 75-87 ISSN 1466-822X R&D Projects: GA MŠk LC06073 Institutional research plan: CEZ:AV0Z60050516 Institutional support: RVO:67985939 Keywords : plant invasions * land-use change * prediction Subject RIV: EF - Botanics Impact factor: 7.223, year: 2012

  3. Phylogenetics and evolution of Trx SET genes in fully sequenced land plants.

    Zhu, Xinyu; Chen, Caoyi; Wang, Baohua

    2012-04-01

    Plant Trx SET proteins are involved in H3K4 methylation and play a key role in plant floral development. Genes encoding Trx SET proteins constitute a multigene family in which the copy number varies among plant species and functional divergence appears to have occurred repeatedly. To investigate the evolutionary history of the Trx SET gene family, we made a comprehensive evolutionary analysis on this gene family from 13 major representatives of green plants. A novel clustering (here named as cpTrx clade), which included the III-1, III-2, and III-4 orthologous groups, previously resolved was identified. Our analysis showed that plant Trx proteins possessed a variety of domain organizations and gene structures among paralogs. Additional domains such as PHD, PWWP, and FYR were early integrated into primordial SET-PostSET domain organization of cpTrx clade. We suggested that the PostSET domain was lost in some members of III-4 orthologous group during the evolution of land plants. At least four classes of gene structures had been formed at the early evolutionary stage of land plants. Three intronless orphan Trx SET genes from the Physcomitrella patens (moss) were identified, and supposedly, their parental genes have been eliminated from the genome. The structural differences among evolutionary groups of plant Trx SET genes with different functions were described, contributing to the design of further experimental studies.

  4. The Influence of Land Use Intensity on the Plant-Associated Microbiome of Dactylis glomerata L.

    Jennifer Estendorfer

    2017-06-01

    Full Text Available In this study, we investigated the impact of different land use intensities (LUI on the root-associated microbiome of Dactylis glomerata (orchardgrass. For this purpose, eight sampling sites with different land use intensity levels but comparable soil properties were selected in the southwest of Germany. Experimental plots covered land use levels from natural grassland up to intensively managed meadows. We used 16S rRNA gene based barcoding to assess the plant-associated community structure in the endosphere, rhizosphere and bulk soil of D. glomerata. Samples were taken at the reproductive stage of the plant in early summer. Our data indicated that roots harbor a distinct bacterial community, which clearly differed from the microbiome of the rhizosphere and bulk soil. Our results revealed Pseudomonadaceae, Enterobacteriaceae and Comamonadaceae as the most abundant endophytes independently of land use intensity. Rhizosphere and bulk soil were dominated also by Proteobacteria, but the most abundant families differed from those obtained from root samples. In the soil, the effect of land use intensity was more pronounced compared to root endophytes leading to a clearly distinct pattern of bacterial communities under different LUI from rhizosphere and bulk soil vs. endophytes. Overall, a change of community structure on the plant–soil interface was observed, as the number of shared OTUs between all three compartments investigated increased with decreasing land use intensity. Thus, our findings suggest a stronger interaction of the plant with its surrounding soil under low land use intensity. Furthermore, the amount and quality of available nitrogen was identified as a major driver for shifts in the microbiome structure in all compartments.

  5. Arid Zone Hydrology

    Arid zone hydrology encompasses a wide range of topics and hydro-meteorological and ecological characteristics. Although arid and semi-arid watersheds perform the same functions as those in humid environments, their hydrology and sediment transport characteristics cannot be readily predicted by inf...

  6. Biological Invasion Influences the Outcome of Plant-Soil Feedback in the Invasive Plant Species from the Brazilian Semi-arid.

    de Souza, Tancredo Augusto Feitosa; de Andrade, Leonaldo Alves; Freitas, Helena; da Silva Sandim, Aline

    2017-05-30

    Plant-soil feedback is recognized as the mutual interaction between plants and soil microorganisms, but its role on the biological invasion of the Brazilian tropical seasonal dry forest by invasive plants still remains unclear. Here, we analyzed and compared the arbuscular mycorrhizal fungi (AMF) communities and soil characteristics from the root zone of invasive and native plants, and tested how these AMF communities affect the development of four invasive plant species (Cryptostegia madagascariensis, Parkinsonia aculeata, Prosopis juliflora, and Sesbania virgata). Our field sampling revealed that AMF diversity and frequency of the Order Diversisporales were positively correlated with the root zone of the native plants, whereas AMF dominance and frequency of the Order Glomerales were positively correlated with the root zone of invasive plants. We grew the invasive plants in soil inoculated with AMF species from the root zone of invasive (I changed ) and native (I unaltered ) plant species. We also performed a third treatment with sterilized soil inoculum (control). We examined the effects of these three AMF inoculums on plant dry biomass, root colonization, plant phosphorous concentration, and plant responsiveness to mycorrhizas. We found that I unaltered and I changed promoted the growth of all invasive plants and led to a higher plant dry biomass, mycorrhizal colonization, and P uptake than control, but I changed showed better results on these variables than I unaltered . For plant responsiveness to mycorrhizas and fungal inoculum effect on plant P concentration, we found positive feedback between changed-AMF community (I changed ) and three of the studied invasive plants: C. madagascariensis, P. aculeata, and S. virgata.

  7. Studies of Physcomitrella patens reveal that ethylene-mediated submergence responses arose relatively early in land-plant evolution

    Yasumura, Yuki; Pierik, Ronald; Fricker, Mark D.; Voesenek, Laurentius A. C. J.; Harberd, Nicholas P.

    2012-01-01

    in the evolution of land plants. We also show that a major component of the bryophyte submergence response is controlled by the phytohormone ethylene, using a perception mechanism that has subsequently been conserved throughout the evolution of land plants. Thus a

  8. A synthesis of terrestrial mercury in the western United States: Spatial distribution defined by land cover and plant productivity

    Obrist, Daniel; Pearson, Christopher; Webster, Jackson; Kane, Tyler J.; Lin, Che-Jen; Aiken, George R.; Alpers, Charles N.

    2016-01-01

    A synthesis of published vegetation mercury (Hg) data across 11 contiguous states in the western United States showed that aboveground biomass concentrations followed the order: leaves (26 μg kg− 1) ~ branches (26 μg kg− 1) > bark (16 μg kg− 1) > bole wood (1 μg kg− 1). No spatial trends of Hg in aboveground biomass distribution were detected, which likely is due to very sparse data coverage and different sampling protocols. Vegetation data are largely lacking for important functional vegetation types such as shrubs, herbaceous species, and grasses.Soil concentrations collected from the published literature were high in the western United States, with 12% of observations exceeding 100 μg kg− 1, reflecting a bias toward investigations in Hg-enriched sites. In contrast, soil Hg concentrations from a randomly distributed data set (1911 sampling points; Smith et al., 2013a) averaged 24 μg kg− 1 (A-horizon) and 22 μg kg− 1 (C-horizon), and only 2.6% of data exceeded 100 μg kg− 1. Soil Hg concentrations significantly differed among land covers, following the order: forested upland > planted/cultivated > herbaceous upland/shrubland > barren soils. Concentrations in forests were on average 2.5 times higher than in barren locations. Principal component analyses showed that soil Hg concentrations were not or weakly related to modeled dry and wet Hg deposition and proximity to mining, geothermal areas, and coal-fired power plants. Soil Hg distribution also was not closely related to other trace metals, but strongly associated with organic carbon, precipitation, canopy greenness, and foliar Hg pools of overlying vegetation. These patterns indicate that soil Hg concentrations are related to atmospheric deposition and reflect an overwhelming influence of plant productivity — driven by water availability — with productive landscapes showing high soil Hg accumulation and unproductive barren soils and shrublands

  9. Origin of land plants: Do conjugating green algae hold the key?

    Melkonian Michael

    2011-04-01

    Full Text Available Abstract Background The terrestrial habitat was colonized by the ancestors of modern land plants about 500 to 470 million years ago. Today it is widely accepted that land plants (embryophytes evolved from streptophyte algae, also referred to as charophycean algae. The streptophyte algae are a paraphyletic group of green algae, ranging from unicellular flagellates to morphologically complex forms such as the stoneworts (Charales. For a better understanding of the evolution of land plants, it is of prime importance to identify the streptophyte algae that are the sister-group to the embryophytes. The Charales, the Coleochaetales or more recently the Zygnematales have been considered to be the sister group of the embryophytes However, despite many years of phylogenetic studies, this question has not been resolved and remains controversial. Results Here, we use a large data set of nuclear-encoded genes (129 proteins from 40 green plant taxa (Viridiplantae including 21 embryophytes and six streptophyte algae, representing all major streptophyte algal lineages, to investigate the phylogenetic relationships of streptophyte algae and embryophytes. Our phylogenetic analyses indicate that either the Zygnematales or a clade consisting of the Zygnematales and the Coleochaetales are the sister group to embryophytes. Conclusions Our analyses support the notion that the Charales are not the closest living relatives of embryophytes. Instead, the Zygnematales or a clade consisting of Zygnematales and Coleochaetales are most likely the sister group of embryophytes. Although this result is in agreement with a previously published phylogenetic study of chloroplast genomes, additional data are needed to confirm this conclusion. A Zygnematales/embryophyte sister group relationship has important implications for early land plant evolution. If substantiated, it should allow us to address important questions regarding the primary adaptations of viridiplants during the

  10. Studies of Physcomitrella patens reveal that ethylene-mediated submergence responses arose relatively early in land-plant evolution

    Yasumura, Yuki

    2012-10-18

    Colonization of the land by multicellular green plants was a fundamental step in the evolution of life on earth. Land plants evolved from fresh-water aquatic algae, and the transition to a terrestrial environment required the acquisition of developmental plasticity appropriate to the conditions of water availability, ranging from drought to flood. Here we show that extant bryophytes exhibit submergence-induced developmental plasticity, suggesting that submergence responses evolved relatively early in the evolution of land plants. We also show that a major component of the bryophyte submergence response is controlled by the phytohormone ethylene, using a perception mechanism that has subsequently been conserved throughout the evolution of land plants. Thus a plant environmental response mechanism with major ecological and agricultural importance probably had its origins in the very earliest stages of the colonization of the land. © 2012 Blackwell Publishing Ltd.

  11. Alterations in flowering strategies and sexual allocation of Caragana stenophylla along a climatic aridity gradient

    Lina Xie; Hongyu Guo; Chengcang Ma

    2016-01-01

    Plant can alter reproductive strategies for adaptation to different environments. However, alterations in flowering strategies and sexual allocation for the same species growing in different environments still remain unclear. We examined the sexual reproduction parameters of Caragana stenophylla across four climatic zones from semi-arid, arid, very arid, to intensively arid zones in the Inner Mongolia Steppe, China. Under the relatively favorable climatic conditions of semi-arid zone, C. sten...

  12. Risk-based design of process plants with regard to domino effects and land use planning

    Khakzad, Nima, E-mail: nkhakzad@gmail.com [Safety and Security Science Group (S3G), Faculty of Technology, Policy and Management, TU Delft, Delft (Netherlands); Reniers, Genserik [Safety and Security Science Group (S3G), Faculty of Technology, Policy and Management, TU Delft, Delft (Netherlands); Antwerp Research Group on Safety and Security (ARGoSS), Faculty of Applied Economics, Universiteit Antwerpen, Antwerp (Belgium); Research Group CEDON, Campus Brussels, KULeuven, Brussels (Belgium)

    2015-12-15

    Highlights: • A Bayesian network methodology has been developed to estimate the total probability of major accidents in chemical plants. • Total probability of accidents includes the probability of individual accidents and potential domino effects. • The methodology has been extended to calculate on-site and off-site risks. • The results of the risk analysis have been used in a multi-criteria decision analysis technique to risk-based design of chemical plants. - Abstract: Land use planning (LUP) as an effective and crucial safety measure has widely been employed by safety experts and decision makers to mitigate off-site risks posed by major accidents. Accordingly, the concept of LUP in chemical plants has traditionally been considered from two perspectives: (i) land developments around existing chemical plants considering potential off-site risks posed by major accidents and (ii) development of existing chemical plants considering nearby land developments and the level of additional off-site risks the land developments would be exposed to. However, the attempts made to design chemical plants with regard to LUP requirements have been few, most of which have neglected the role of domino effects in risk analysis of major accidents. To overcome the limitations of previous work, first, we developed a Bayesian network methodology to calculate both on-site and off-site risks of major accidents while taking domino effects into account. Second, we combined the results of risk analysis with Analytic Hierarchical Process to design an optimal layout for which the levels of on-site and off-site risks would be minimum.

  13. Pathways to Resilience in Semi-Arid Economies (PRISE)

    rlarbey

    PRISE Goal. This research will support the emergence of equitable, climate resilient economic development in semi-arid lands through research excellence and ... change in semi-arid areas, and how is the private sector adapting? 4. How do ... Role. Individual. Contact email. Lead Principal Investigator. Dr Tom Mitchell.

  14. Dynamics of traditional knowledge of medicinal plants in a rural community in the Brazilian semi-arid region

    Flávia dos Santos Silva

    2011-06-01

    Full Text Available Human beings have accumulated rich experience with natural resources over time, but such knowledge can be strongly influenced by several factors, such as age, sex and occupation. This study focuses on the influence of these factors on knowledge of medicinal plants in a rural community in northeastern Brazil. Data were collected through semi-structured interviews with 102 people, with the number of plants and uses cited studied for quantitative analysis. Through this research, it was possible to show that the social variables studied (age, sex and informants occupation have contributed to the formation of different patterns of knowledge regarding medicinal resources. The results indicate that awareness of this dynamic is necessary for the proper implementation of projects where the goal is the sustainable use of natural resources (because it indicates the different levels of knowledge within a community, for studies intended to discover new drugs (because it indicates the peculiarities of certain groups, and for biodiversity conservation strategies.

  15. Spatial-temporal variation of marginal land suitable for energy plants from 1990 to 2010 in China

    Jiang, Dong; Hao, Mengmeng; Fu, Jingying; Zhuang, Dafang; Huang, Yaohuan

    2014-01-01

    Energy plants are the main source of bioenergy which will play an increasingly important role in future energy supplies. With limited cultivated land resources in China, the development of energy plants may primarily rely on the marginal land. In this study, based on the land use data from 1990 to 2010(every 5 years is a period) and other auxiliary data, the distribution of marginal land suitable for energy plants was determined using multi-factors integrated assessment method. The variation of land use type and spatial distribution of marginal land suitable for energy plants of different decades were analyzed. The results indicate that the total amount of marginal land suitable for energy plants decreased from 136.501 million ha to 114.225 million ha from 1990 to 2010. The reduced land use types are primarily shrub land, sparse forest land, moderate dense grassland and sparse grassland, and large variation areas are located in Guangxi, Tibet, Heilongjiang, Xinjiang and Inner Mongolia. The results of this study will provide more effective data reference and decision making support for the long-term planning of bioenergy resources. PMID:25056520

  16. Intensive land use drives small-scale homogenization of plant- and leafhopper communities and promotes generalists.

    Chisté, Melanie N; Mody, Karsten; Kunz, Gernot; Gunczy, Johanna; Blüthgen, Nico

    2018-02-01

    The current biodiversity decline through anthropogenic land-use not only involves local species losses, but also homogenization of communities, with a few generalist species benefitting most from human activities. Most studies assessed community heterogeneity (β-diversity) on larger scales by comparing different sites, but little is known about impacts on β-diversity within each site, which is relevant for understanding variation in the level of α-diversity, the small-scale distribution of species and associated habitat heterogeneity. To obtain our dataset with 36,899 individuals out of 117 different plant- and leafhopper (Auchenorrhyncha) species, we sampled communities of 140 managed grassland sites across Germany by quantitative vacuum suction of five 1 m 2 plots on each site. Sites differed in land-use intensity as characterized by intensity of fertilization, mowing and grazing. Our results demonstrate a significant within-site homogenization of plant- and leafhopper communities with increasing land-use intensity. Correspondingly, density (- 78%) and γ-diversity (- 35%) declined, particularly with fertilization and mowing intensity. More than 34% of plant- and leafhopper species were significant losers and only 6% were winners of high land-use intensity, with abundant and widespread species being less affected. Increasing land-use intensity adversely affected dietary specialists and promoted generalist species. Our study emphasizes considerable, multifaceted effects of land-use intensification on species loss, with a few dominant generalists winning, and an emerging trend towards more homogenized assemblages. By demonstrating homogenization for the first time within sites, our study highlights that anthropogenic influences on biodiversity even occur on small scales.

  17. Role of land-based prototype plants in propulsion nuclear power plants engineering

    Voronin, V.E.; Prokhorov, Yu.A.

    1993-01-01

    Prototype plants provide a powerful tool for accomplishing tasks of development and construction of newly designed new power plants (NPPs). Leaving aside momentary political or economical considerations, one should admit that the use of prototype plants in testing of new NPPs is quite a necessity. To make the most of prototype plant, its commissioning should precede lead plant construction by 2-3 years. To make good use of prototype plants, a set of basic requirements should be fulfilled: greatest possible identity beteen the facility under test and a new series NPP; provision of high performance data acquisitoin, processing and storage firmware and a modelling system using update computer technique; and developed science infrastructure, engineering support and adequate maintenance. Prototype plants should comply with safety requirements to meet environmental protection standards

  18. A methodology for evaluating land suitability for medicinal plants at a regional level

    Marco Barbaro

    2011-12-01

    Full Text Available Before introducing a new crop in an area, such as medicinal plant species, crop-land suitability analysis is a prerequisite to achieve an optimum exploitation of the available land resources for a sustainable agricultural production. To evaluate the land suitability it is important to take into account the habitats of the plant species. Moreover, agronomic, logistic and product quality aspects have to be considered. The importance of these aspects changes according to the stakeholders: the local government is more involved in supporting environmental suitability and production sustainability, farmers need areas which satisfy agronomic and logistic requirements, while industry is interested in the quality of production. A methodology was developed and implemented to create suitability maps for medicinal plants. Because of the generally limited information about medicinal plant adaptation, a simple methodology, based on a priori information has been developed, based on three different criteria: i environmental suitability (point of view of local government; ii agronomic, productivity and logistic suitability (point of view of the farmer; iii quality suitability (point of view of industry. For each of the three criteria, a specific macro-indicator, based on land characteristics, was calculated using membership functions. Here, a methodology to create maps for the introduction of such species was developed and implemented. This methodology can be repeated by command scripts in an easy-to-use freeware GIS. The structure of the evaluation model can be easily adapted to consider more detailed land information like climate and soil. The methodology (implemented by scripts in a freeware GIS, can be easily repeated and adapted for other situations.

  19. The current bioenergy production potential of semi-arid and arid regions in sub-Saharan Africa

    Wicke, B.; Smeets, E.M.W.; Watson, H.; Faaij, A.P.C.

    2011-01-01

    This article assesses the current technical and economic potential of three bioenergy production systems (cassava ethanol, jatropha oil and fuelwood) in semi-arid and arid regions of eight sub-Saharan African countries. The results indicate that the availability of land for energy production ranges

  20. Contractual practice and land conflicts : the "Plant & Share" arrangement in Côte d'Ivoire

    Colin, Jean-Philippe

    2017-01-01

    This paper tackles the broad issue of agrarian contracts, property rights and conflicts in the context of rural Côte d'Ivoire. Since the beginning of the 2000s, a new type of contractual arrangement has been developing rapidly: the 'Plant & Share' contract. Through such a contract, a landowner provides the land to a farmer who develops a perennial tree crop plantation; when production starts, the plantation, the plantation and the land, or the product is shared. The aim of the paper is to dis...

  1. Use of environmental isotopes in arid zone hydrology

    Dincer, T.

    1980-01-01

    After aridity is defined some physical and hydrologic features common in arid lands are described. An attempt has been made to identify various groundwater recharge mechanisms in arid countries and to assess their relative importance. The influence of the arid climates on the isotopic composition of the precipitation is discussed. The use of environmental isotopes in run-off and precipitation infiltration and recharge is evaluated, and the importance of isotopic studies in investigating interrelations between aquifers is stressed. Finally, some examples of isotope applications in surface water and its relation to groundwater are given. (author)

  2. Tree cover, tree height and bare soil cover differences along a land use degradation gradient in semi-arid savannas, South Africa

    Mathieu, R

    2009-07-01

    Full Text Available High resolution airborne hyperspectral and discrete return LiDAR data were used to assess bare soil and tree cover differences along a land use transect consisting of state-owned, privately-owned conservation areas, and communal areas in South...

  3. The dominant role of semi-arid ecosystems in the trend and variability of the land CO2 sink

    Ahlström, Anders; Raupach, Michael R.; Schurgers, Guy

    2015-01-01

    to that variability are not well known. Using an ensemble of ecosystem and land-surface models and an empirical observation-based product of global gross primary production, we show that the mean sink, trend, and interannual variability in CO2 uptake by terrestrial ecosystems are dominated by distinct biogeographic...

  4. Establishment of land model at the Shika Nuclear Power Plant. Mainly, on rock board classification

    Katagawa, Hideki; Hashimoto, Toru; Hirano, Shuji

    1999-01-01

    In order to grasp engineering properties of basic land of constructions, there is rock board classification as a method to classify whole of rock board to some groups considerable to be nearly equal on its properties. Among the method, various methods in response to its aim and characteristics are devised, and for a classification to hard rock board, the Denken type rock board classification considering degree of weathering to its main element and so forth are well known. The basic rock board of the Shika Nuclear Power Plant is composed of middle and hard types of rock, and its weathering is limited to its shallow portion, most of which are held at fresh condition. For such land, a new classification standard in response to characteristics of land was established. Here were introduced on a progress to establish a new classification standard, its application results and rock board properties. (G.K.)

  5. Land

    Audouin, M

    2007-01-01

    Full Text Available the factors contributing to desertification and practical measures necessary to combat desertification and mitigate the effect of drought. The priority issues reported on in this chapter are soil and veld degradation, and the loss of land for agricultural use....

  6. Complete plastome sequences of Equisetum arvense and Isoetes flaccida: implications for phylogeny and plastid genome evolution of early land plant lineages

    Karol, Kenneth G; Arumuganathan, Kathiravetpillai; Boore, Jeffrey L; Duffy, Aaron M; Everett, Karin DE; Hall, John D; Hansen, S Kellon; Kuehl, Jennifer V; Mandoli, Dina F; Mishler, Brent D; Olmstead, Richard G; Renzaglia, Karen S; Wolf, Paul G

    2010-01-01

    Abstract Background Despite considerable progress in our understanding of land plant phylogeny, several nodes in the green tree of life remain poorly resolved. Furthermore, the bulk of currently available data come from only a subset of major land plant clades. Here we examine early land plant evolution using complete plastome sequences including two previously unexamined and phylogenetically critical lineages. To better understand the evolution of land plants and their plastomes, we examined...

  7. The effectiveness of arbuscular-mycorrhizal fungi and Aspergillus niger or Phanerochaete chrysosporium treated organic amendments from olive residues upon plant growth in a semi-arid degraded soil.

    Medina, A; Roldán, A; Azcón, R

    2010-12-01

    Arbuscular mycorrhizal (AM) fungi and a residue from dry olive cake (DOC) supplemented with rock phosphate (RP) and treated with either Aspergillus niger (DOC-A) or Phanerochaete chrysosporium (DOC-P), were assayed in a natural, semi-arid soil using Trifolium repens or Dorycnium pentaphyllum plants. The effects of the AM fungi and/or DOC-A were compared with P-fertilisation (P) over eleven successive harvests to evaluate the persistence of the effectiveness of the treatments. The biomass of dually-treated plants after four successive harvests was greater than that obtained for non-treated plants or those receiving the AM inoculum or DOC-A treatments after eleven yields. The AM inoculation was critical for obtaining plant growth benefit from the application of fermented DOC-A residue. The abilities of the treatments to prevent plant drought stress were also assayed. Drought-alleviating effects were evaluated in terms of plant growth, proline and total sugars concentration under alternative drought and re-watering conditions (8th and 9th harvests). The concentrations of both compounds in plant biomass increased under drought when DOC-A amendment and AM inoculation were employed together: they reinforced the plant drought-avoidance capabilities and anti-oxidative defence. Water stress was less compensated in P-fertilised than in DOC-A-treated plants. DOC-P increased D. pentaphyllum biomass, shoot P content, nodule number and AM colonisation, indicating the greater DOC-transforming ability of P. chrysosporium compared to A. niger. The lack of AM colonisation and nodulation in this soil was compensated by the application of DOC-P, particularly with AM inoculum. The management of natural resources (organic amendments and soil microorganisms) represents an important strategy that assured the growth, nutrition and plant establishment in arid, degraded soils, preventing the damage that arises from limited water and nutrient supply. Copyright © 2010 Elsevier Ltd. All rights

  8. Recent water quality trends in a typical semi-arid river with a sharp decrease in streamflow and construction of sewage treatment plants

    Cheng, Peng; Li, Xuyong; Su, Jingjun; Hao, Shaonan

    2018-01-01

    Identification of the interactive responses of water quantity and quality to changes in nature and human stressors is important for the effective management of water resources. Many studies have been conducted to determine the influence of these stressors on river discharge and water quality. However, there is little information about whether sewage treatment plants can improve water quality in a region where river streamflow has decreased sharply. In this study, a seasonal trend decomposition method was used to analyze long-term (1996-2015) and seasonal trends in the streamflow and water quality of the Guanting Reservoir Basin, which is located in a semi-arid region of China. The results showed that the streamflow in the Guanting Reservoir Basin decreased sharply from 1996-2000 due to precipitation change and human activities (human use and reservoir regulation), while the streamflow decline over the longer period of time (1996-2015) could be attributed to human activities. During the same time, the river water quality improved significantly, having a positive relationship with the capacity of wastewater treatment facilities. The water quality in the Guanting Reservoir showed a deferred response to the reduced external loading, due to internal loading from sediments. These results implied that for rivers in which streamflow has declined sharply, the water quality could be improved significantly by actions to control water pollution control. This study not only provides useful information for water resource management in the Guanting Reservoir Basin, but also supports the implementation of water pollution control measures in other rivers with a sharp decline in streamflow.

  9. Sustainability of Smallholder Agriculture in Semi-Arid Areas under Land Set-aside Programs: A Case Study from China’s Loess Plateau

    Qirui Li

    2016-04-01

    Full Text Available This article analyzes agricultural sustainability in the context of land degradation, rural poverty and social inequality, taking China’s Loess Hills as an example. The analysis attempts to understand the multi-dimensionality of sustainability at the farm level and its relationship with physical-socio-economic-infrastructural-technological framework conditions in the context of the land set-aside program viz. the Grain for Green Project (GGP. We developed composite indices of sustainability and its environmental, economic and social dimensions using a principal component analysis (PCA-based weighting scheme. Regression analyses were conducted to examine the relationship between the estimated sustainability indicators and the variables representing framework conditions of knowledge, demographics, resource endowment and production techniques. The stated analysis was conducted on a dataset collected by means of household surveys in 2014 in valleys and flood plain areas in Yanhe Township. Findings reveal hidden correlations among the indicators of environmental, economic, and social pillars of sustainability. The ratio of land under the conservation program to actual farmland emerged as a key determinant of overall agricultural sustainability and its social dimension, which reaches the maximum when the ratio is around 0.56 and 0.64, respectively. The results also show that there is need to balance off-farm and on-farm income diversification as well as highlight the role of women in ensuring the sustainability of farming households. The core achievement of the article is the definition of the thresholds for the land set-aside program and the identification of major determinants of agricultural sustainability in the rural Chinese context in particular and in rural farming communities in general.

  10. Ion and metabolite transport in the chloroplast of algae: lessons from land plants.

    Marchand, Justine; Heydarizadeh, Parisa; Schoefs, Benoît; Spetea, Cornelia

    2018-06-01

    Chloroplasts are endosymbiotic organelles and play crucial roles in energy supply and metabolism of eukaryotic photosynthetic organisms (algae and land plants). They harbor channels and transporters in the envelope and thylakoid membranes, mediating the exchange of ions and metabolites with the cytosol and the chloroplast stroma and between the different chloroplast subcompartments. In secondarily evolved algae, three or four envelope membranes surround the chloroplast, making more complex the exchange of ions and metabolites. Despite the importance of transport proteins for the optimal functioning of the chloroplast in algae, and that many land plant homologues have been predicted, experimental evidence and molecular characterization are missing in most cases. Here, we provide an overview of the current knowledge about ion and metabolite transport in the chloroplast from algae. The main aspects reviewed are localization and activity of the transport proteins from algae and/or of homologues from other organisms including land plants. Most chloroplast transporters were identified in the green alga Chlamydomonas reinhardtii, reside in the envelope and participate in carbon acquisition and metabolism. Only a few identified algal transporters are located in the thylakoid membrane and play role in ion transport. The presence of genes for putative transporters in green algae, red algae, diatoms, glaucophytes and cryptophytes is discussed, and roles in the chloroplast are suggested. A deep knowledge in this field is required because algae represent a potential source of biomass and valuable metabolites for industry, medicine and agriculture.

  11. The Effects of Water-Absorbent Materials on Water Supply for Tree Planting in the Semi-Arid Regions

    Gholam Reza Davarpanah Davarpanah

    2005-03-01

    Full Text Available Numerous studies have so far been focused on increasing irrigation efficiency through such measures as soil moisture retention and soil moisture capacity as well as improving soil physical conditions. In this study, surface runoff reduction, deep penetration of rain water, and use of rain water at irrigation sites with the help of water absorbent chemicals were investigated as measures of supplying for tree water demand and also of reducing drought effects. The absorbent material was purchased from Iran Polymer Research Center. The experimental design included three independent experiments in a completely randomized block design (CRBD with 5 treatments (0, 50, 100, 150 and 200 gr. of the absorbent material and three replications. The tree species used in the experiments were Amygdalus sp., Vitis vinifera, and Pistacia vera. There were 5 experimental units with 4 trees planted 3×3 meters apart. Appropriate amounts of the test material (absorbent were mixed with soil. Three characters of survival including: growth diameter, height, and canopy cover were recorded 4 times a year over two consecutive years. Mstat-c statistical software was used in the statistical analysis (Factor option. Results showed that the tree species had significant differences in their survival due to their genetic and physiological characteristics, so that the species of Vitis vinifera and Pistacia vera recorded the minimum and maximum survival values, respectively. Data collection within the present study is suggested to be continued and similar studies with light and sandy textured soils under greenhouse conditions are needed in order to gain more accurate information on these effects.

  12. A methodology for small scale rural land use mapping in semi-arid developing countries using orbital imagery. Part 6: A low-cost method for land use mapping using simple visual techniques of interpretation. [Spain

    Vangenderen, J. L. (Principal Investigator); Lock, B. F.

    1976-01-01

    The author has identified the following significant results. It was found that color composite transparencies and monocular magnification provided the best base for land use interpretation. New methods for determining optimum sample sizes and analyzing interpretation accuracy levels were developed. All stages of the methodology were assessed, in the operational sense, during the production of a 1:250,000 rural land use map of Murcia Province, Southeast Spain.

  13. Effects Of Land Use On The Nature And Population Of Microorganisms In The Semi-Arid Region Of North-Eastern Nigeria

    HS Bello

    2013-12-01

    Full Text Available This study was aim to investigate the effects of land use on the nature and population of microorganisms in soil from five different farms within University of Maiduguri, Borno State. A total of ten composite samples were obtained and analyzed in the laboratory. The total microbial population was consistently higher in the grazing reserved land with mean of 105x104CFU/g than in cultivated farms with means of 84.5x104CFU/g, 66x104CFU/g and 66x104CFU/g, for cereal (sorghum, beans and tomato farms respectively. The site with the least microbial population was gum-Arabic plantation with the mean of 29x104CFU/g. Bacteria were the most dominant species at all sites regardless of depths. International Journal of Environment, Volume-2, Issue-1, Sep-Nov 2013, Pages 224-230 DOI: http://dx.doi.org/10.3126/ije.v2i1.9223

  14. Invasiveness does not predict impact: response of native land snail communities to plant invasions in riparian habitats

    Horáčková, J.; Juřičková, L.; Šizling, A. L.; Jarošík, Vojtěch; Pyšek, Petr

    2014-01-01

    Roč. 9, č. 9 (2014), s. 1-10, e108296 E-ISSN 1932-6203 Institutional support: RVO:67985939 Keywords : plant invasions * land snails * impact Subject RIV: EF - Botanics Impact factor: 3.234, year: 2014

  15. The Physcomitrella genome reveals evolutionary insights into the conquest of land by plants

    Rensing, Stefan A.; Lang, Daniel; Zimmer, Andreas D.; Terry, Astrid; Salamov, Asaf; Shapiro, Harris; Nishiyama, Tomaoki; Perroud, Pierre-Francois; Lindquist, Erika A.; Kamisugi, Yasuko; Tanahashi, Takako; Sakakibara, Keiko; Fujita, Tomomichi; Oishi, Kazuko; Shin, Tadasu; Kuroki, Yoko; Toyoda, Atsushi; Suzuki, Yutaka; Hashimoto, Shin-ichi; Yamaguchi, Kazuo; Sugano, Sumio; Kohara, Yuji; Fujiyama, Asao; Anterola, Aldwin; Aoki, Setsuyuki; Ashton, Neil; Barbazuk, W. Brad; Barker, Elizabeth; Bennetzen, Jeffrey L.; Blankenship, Robert; Cho, Sung Hyun; Dutcher, Susan K.; Estelle, Mark; Fawcett, Jeffrey A.; Gundlach, Heidrum; Hanada, Kousuke; Melkozernov, Alexander; Murata, Takashi; Nelson, David R.; Pils, Birgit; Prigge, Michael; Reiss, Bernd; Renner, Tanya; Rombauts, Stephane; Rushton, Paul J.; Sanderfoot, Anton; Schween, Gabriele; Shiu, Shin-Han; Stueber, Kurt; Theodoulou, Frederica L.; Tu, Hank; Van de Peer, Yves; Verrier, Paul J.; Waters, Elizabeth; Wood, Andrew; Yang, Lixing; Cove, David; Cuming, Andrew C.; Hasebe, Mitsayasu; Lucas, Susan; Mishler, Brent D.; Reski, Ralf; Grigoriev, Igor V.; Quatrano, Rakph S.; Boore, Jeffrey L.

    2007-09-18

    We report the draft genome sequence of the model moss Physcomitrella patens and compare its features with those of flowering plants, from which it is separated by more than 400 million years, and unicellular aquatic algae. This comparison reveals genomic changes concomitant with the evolutionary movement to land, including a general increase in gene family complexity; loss of genes associated with aquatic environments (e.g., flagellar arms); acquisition of genes for tolerating terrestrial stresses (e.g., variation in temperature and water availability); and the development of the auxin and abscisic acid signaling pathways for coordinating multicellular growth and dehydration response. The Physcomitrella genome provides a resource for phylogenetic inferences about gene function and for experimental analysis of plant processes through this plant's unique facility for reverse genetics.

  16. Soil and Plant Water Relations Determine Photosynthetic Responses of C3 and C4 Grasses in a Semi‐arid Ecosystem under Elevated CO2

    LECAIN, DANIEL R.; MORGAN, JACK A.; MOSIER, ARVIN R.; NELSON, JIM A.

    2003-01-01

    To model the effect of increasing atmospheric CO2 on semi‐arid grasslands, the gas exchange responses of leaves to seasonal changes in soil water, and how they are modified by CO2, must be understood for C3 and C4 species that grow in the same area. In this study, open‐top chambers were used to investigate the photosynthetic and stomatal responses of Pascopyrum smithii (C3) and Bouteloua gracilis (C4) grown at 360 (ambient CO2) and 720 µmol mol–1 CO2 (elevated CO2) in a semi‐arid shortgrass s...

  17. STUDIES ON FUNCTIONAL BACTERIA OF INDONESIAN TROPICAL FOREST PLANTS FOR BIOREHABILITATION OF DEGRADED LANDS

    Irnayuli R. Sitepu

    2008-06-01

    Full Text Available Forest  degradations  have left vast amount  of damaged  and abandoned  lands in Indonesia.   In this paper, we present our approaches  in rehabilitation of adverse soils using functional  bacteria isolated from plant species of Indonesian tropical  rain forests. For these purposes,  we collected  bacteria  from various  bio-geo-climatically different forests and conducted bioassays to test these bacterial abilities in improving plant growth. Repeated seedling-based studies on Shorea spp., Alstonia scholaris, Acacia crassicarpa, and Agathis lorantifolia have revealed that many bacteria were able to promote plant growth at early stage in the nursery.  Various  plant responses towards  inoculations suggested that although  forest soils maintain  highly diverse and potent  bacteria,  it is necessary to select appropriate approaches to obtain optimum  benefits from these plant-bacteria interactions.  Our  ideas and futures  studies  for further  management  of these plant- bacteria interactions for biorehabilitation are also discussed.

  18. Predicting plant diversity patterns in Madagascar: understanding the effects of climate and land cover change in a biodiversity hotspot.

    Kerry A Brown

    Full Text Available Climate and land cover change are driving a major reorganization of terrestrial biotic communities in tropical ecosystems. In an effort to understand how biodiversity patterns in the tropics will respond to individual and combined effects of these two drivers of environmental change, we use species distribution models (SDMs calibrated for recent climate and land cover variables and projected to future scenarios to predict changes in diversity patterns in Madagascar. We collected occurrence records for 828 plant genera and 2186 plant species. We developed three scenarios, (i.e., climate only, land cover only and combined climate-land cover based on recent and future climate and land cover variables. We used this modelling framework to investigate how the impacts of changes to climate and land cover influenced biodiversity across ecoregions and elevation bands. There were large-scale climate- and land cover-driven changes in plant biodiversity across Madagascar, including both losses and gains in diversity. The sharpest declines in biodiversity were projected for the eastern escarpment and high elevation ecosystems. Sharp declines in diversity were driven by the combined climate-land cover scenarios; however, there were subtle, region-specific differences in model outputs for each scenario, where certain regions experienced relatively higher species loss under climate or land cover only models. We strongly caution that predicted future gains in plant diversity will depend on the development and maintenance of dispersal pathways that connect current and future suitable habitats. The forecast for Madagascar's plant diversity in the face of future environmental change is worrying: regional diversity will continue to decrease in response to the combined effects of climate and land cover change, with habitats such as ericoid thickets and eastern lowland and sub-humid forests particularly vulnerable into the future.

  19. RCRA closure of eight land-based units at the Y-12 plant

    Stone, J.E.; Welch, S.H.

    1988-01-01

    Eight land-based hazardous waste management units at the Oak Ridge Y-12 Plant are being closed under an integrated multi-year program. Closure plans for the units have been submitted and are in various stages of revision and regulatory review. These units will be closed by various combinations of methods, including liquid removal and treatment, sludge stabilization, contaminated sludge and/or soil removal, and capping. The closure of these sites will be funded by a new Department of Energy budget category, the Environmental Restoration Budget Category (ERBC), which is intended to provide greater flexibility in the response to closure and remedial activities. A major project, Closure and Post-Closure Activities (CAPCA), has been identified for ERBC funding to close and remediate the land units in accordance with RCRA requirements. Establishing the scope of this program has required the development of risk assessments and the preparation of an integrated schedule

  20. Antimicrobial activities of endophytic fungi obtained from the arid zone invasive plant Opuntia dillenii and the isolation of equisetin, from endophytic Fusarium sp.

    Ratnaweera, Pamoda B; de Silva, E Dilip; Williams, David E; Andersen, Raymond J

    2015-07-10

    Opuntia dillenii is an invasive plant well established in the harsh South-Eastern arid zone of Sri Lanka. Evidence suggests it is likely that the endophytic fungal populations of O. dillenii assist the host in overcoming biotic and abiotic stress by producing biologically active metabolites. With this in mind there is potential to discover novel natural products with useful biological activities from this hitherto poorly investigated source. Consequently, an investigation of the antimicrobial activities of the endophytes of O. dillenii, that occupies a unique ecological niche, may well provide useful leads in the discovery of new pharmaceuticals. Endophytic fungi were isolated from the surface sterilized cladodes and flowers of O. dillenii using several nutrient media and the antimicrobial activities were evaluated against three Gram-positive and two Gram-negative bacteria and Candida albicans. The two most bioactive fungi were identified by colony morphology and DNA sequencing. The secondary metabolite of the endophyte Fusarium sp. exhibiting the best activity was isolated via bioassay guided chromatography. The chemical structure was elucidated from the ESIMS and NMR spectroscopic data obtained for the active metabolite. The minimum inhibitory concentrations (MICs) of the active compound were determined. Eight endophytic fungi were isolated from O. dillenii and all except one showed antibacterial activities against at least one of the test bacteria. All extracts were inactive against C. albicans. The most bioactive fungus was identified as Fusarium sp. and the second most active as Aspergillus niger. The structure of the major antibacterial compound of the Fusarium sp. was shown to be the tetramic acid derivative, equisetin. The MIC's for equisetin were 8 μg mL(-1) against Bacillus subtilis, 16 μg mL(-1) against Staphylococcus aureus and Methicillin Resistant Staphylococcus aureus (MRSA). O. dillenii, harbors several endophytic fungi capable of producing

  1. Geographical view on agricultural land and structural changes plant production Montenegro

    G. Rajović

    2014-03-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE This paper analyzes agricultural land and structural changes in plant production Montenegro. The Montenegro represents a significant potential for agricultural development, but plant production insufficiently developed in relation to natural resources and the demands of intensive agricultural production. Average possession by agricultural holdings in 1960 amounts is 5.34 ha with only 2.05 ha arable area per agricultural holdings. Yet more unfavorable is the situation with arable surfaces. Namely, agricultural holdings in the Montenegro in 1960 are on average dispose with maximum of 0.74 ha of arable land. Judging by the size of the cultivated area, production volume, as well as according other parameters, plant production in the Montenegro in 2007, mainly used for meeting need households. A smaller area for is market. The role of the Montenegrin village and agriculture must be first-rate, as are its potentials, the main power future development of Montenegro. This requires radically new relationship between society and science to agriculture and the countryside. Instead of the existing approach in which they observed the preventive as producers of cheap food has to be developed a new concept, a comprehensive agricultural and rural development, which will be based on demographic, natural, economic and socio-cultural potential of Montenegro. 

  2. Post-Fire Peat Land Understory Plant in Rimba Panjang, Sumatera, Indonesia

    Firdaus, L. N.; Nursal; Wulandari, Sri; Syafi'i, Wan; Fauziah, Yuslim

    2017-12-01

    The existence of understory plants during early post-fire succession is essential in term of natural post-fire ecological restoration. More than fifty percent of fire incidents in Riau, Sumatera, Indonesia occurred in shallow peat lands which have the huge impact on vegetation damage. This study aims to explore the understory plants species and diversity in post-fire peat land at Rimba Panjang, Kampar Regency, Sumatera, Indonesia. By using survey method, the observations were conducted on 150 plots which were distributed randomly over four locations based on the year after fire: 2009, 2014, 2015 and 2016. We found respectively 12, 14, 19 and 17 species at that sites with respective Shannon Wiener diversity index were 1.72, 2.00, 2.14 and 2.40. All the sites were dominated by Stenochlaena palustris (Burm.). Coverage percentage of understory vegetation were respectively 28.87%, 25.50%, 51.60% and 54.13%. Overall, we found 31 species of 17 familia. The result showed that the species composition, diversity index and coverage percentage of understory plant are likely to decrease in line with the length of time after the fire. Post peatland fires in Rimba Panjang are still having the characteristics of the peat swamp habitat which was dominated by Stenochlaena palustris (Burm.). Ecological restoration of that habitat is still possible, but it is necessary to consider technological and socio-economical aspects of local communities.

  3. Urban land use decouples plant-herbivore-parasitoid interactions at multiple spatial scales.

    Amanda E Nelson

    Full Text Available Intense urban and agricultural development alters habitats, increases fragmentation, and may decouple trophic interactions if plants or animals cannot disperse to needed resources. Specialist insects represent a substantial proportion of global biodiversity and their fidelity to discrete microhabitats provides a powerful framework for investigating organismal responses to human land use. We sampled site occupancy and densities for two plant-herbivore-parasitoid systems from 250 sites across a 360 km2 urban/agricultural landscape to ask whether and how human development decouples interactions between trophic levels. We compared patterns of site occupancy, host plant density, herbivory and parasitism rates of insects at two trophic levels with respect to landcover at multiple spatial scales. Geospatial analyses were used to identify landcover characters predictive of insect distributions. We found that herbivorous insect densities were decoupled from host tree densities in urban landcover types at several spatial scales. This effect was amplified for the third trophic level in one of the two insect systems: despite being abundant regionally, a parasitoid species was absent from all urban/suburban landcover even where its herbivore host was common. Our results indicate that human land use patterns limit distributions of specialist insects. Dispersal constraints associated with urban built development are specifically implicated as a limiting factor.

  4. Evolution and current state of our understanding of the role played in the climate system by land surface processes in semi-arid regions

    Nicholson, Sharon E.

    2015-10-01

    The role of the land surface in climate and weather has been a major research focus since the 1970s. Since that time our understanding of the issue has greatly changed and many new themes in several disciplines are being considered. This article summarizes the changes in our understanding that have taken place in research on this topic and reviews principally papers that have appeared in the last two decades. Several other papers provide comprehensive reviews of literature that appeared prior to that time. The major changes that have occurred include 1) more sophisticated and rigorous analysis of desertification, 2) increased emphasis on hydrological processes, including the role of groundwater, 3) use of multi-model ensembles and regional models, 4) the emergence of the domain of ecohydrology, with emphasis on detailed feedbacks between water availability and vegetation, 5) examination of the hypothesis that vegetation feedback can produce abrupt climate change, 6) emphasis on the impacts on convective or synoptic-scale systems, and 7) consideration of the impact of aerosols, including the Saharan Air Layer. With the exception of desertification, each of these topics is reviewed.

  5. Optimal Use of Agricultural Water and Land Resources through Reconfiguring Crop Planting Structure under Socioeconomic and Ecological Objectives

    Qian Tan

    2017-07-01

    Full Text Available Many economic, social and ecological problems can be attributed to the scarcity and mismanagement of water and land resources. In this study, a multi-objective fuzzy–robust programming (MOFRP method was developed for supporting the optimal use of land and water resources in agriculture. MOFRP improved existing methods through taking ecological services of crop cultivation into account. It was also capable of reflecting fuzziness in preferences, priorities and parameters that were largely neglected in previous agricultural decision making. This method was applied to address a case in arid northwestern China. Optimal plans of crop cultivation reconfiguration were generated for sustaining local development under economic, ecological and social objectives as well as physical restraints in water and land resources. Compared to the status quo, the optimized plan would increase economic and ecological benefits by 12.2% and 18.8%, respectively. The efficiency of irrigation water could also be enhanced with the economic and ecological benefits per unit water being raised and the water consumption per unit land being reduced. The comparisons of the MOFRP model to four alternatives validated that it was capable of achieving satisfactory benefits and reducing system-violation risks without neglecting valuable uncertain information and ecological services of crops. The proposed method was also applicable to other multi-objective management problems under uncertainty without loss of generality.

  6. Analyses of charophyte chloroplast genomes help characterize the ancestral chloroplast genome of land plants.

    Civaň, Peter; Foster, Peter G; Embley, Martin T; Séneca, Ana; Cox, Cymon J

    2014-04-01

    Despite the significance of the relationships between embryophytes and their charophyte algal ancestors in deciphering the origin and evolutionary success of land plants, few chloroplast genomes of the charophyte algae have been reconstructed to date. Here, we present new data for three chloroplast genomes of the freshwater charophytes Klebsormidium flaccidum (Klebsormidiophyceae), Mesotaenium endlicherianum (Zygnematophyceae), and Roya anglica (Zygnematophyceae). The chloroplast genome of Klebsormidium has a quadripartite organization with exceptionally large inverted repeat (IR) regions and, uniquely among streptophytes, has lost the rrn5 and rrn4.5 genes from the ribosomal RNA (rRNA) gene cluster operon. The chloroplast genome of Roya differs from other zygnematophycean chloroplasts, including the newly sequenced Mesotaenium, by having a quadripartite structure that is typical of other streptophytes. On the basis of the improbability of the novel gain of IR regions, we infer that the quadripartite structure has likely been lost independently in at least three zygnematophycean lineages, although the absence of the usual rRNA operonic synteny in the IR regions of Roya may indicate their de novo origin. Significantly, all zygnematophycean chloroplast genomes have undergone substantial genomic rearrangement, which may be the result of ancient retroelement activity evidenced by the presence of integrase-like and reverse transcriptase-like elements in the Roya chloroplast genome. Our results corroborate the close phylogenetic relationship between Zygnematophyceae and land plants and identify 89 protein-coding genes and 22 introns present in the chloroplast genome at the time of the evolutionary transition of plants to land, all of which can be found in the chloroplast genomes of extant charophytes.

  7. Relationships between soil parameters and vegetation in abandoned terrace fields vs. non-terraced fields in arid lands (Lanzarote, Spain): An opportunity for restoration

    Arévalo, José Ramón; Fernández-Lugo, Silvia; Reyes-Betancort, J. Alfredo; Tejedor, Marisa; Jiménez, Concepción; Díaz, Francisco J.

    2017-11-01

    Over 90% of terraced fields have been abandoned on the island of Lanzarote in the last 40 years. The present work analyses the effects of abandonment on the soil and vegetation recovery of terraced field agroecosystems by comparing them with adjacent non-terraced fields in Lanzarote, Canary Islands (Spain). This information is necessary to take the appropriate management actions to achieve goals such as soil protection and biodiversity conservation. Results indicate that terraced fields display better soil quality than non-terraced ones, as shown by the significant differences found in parameters such as SAR, exchangeable Na, CaCO3, B content, moisture content or soil depth. Moreover, the terraced fields' plant community has more species similarities with the native plant community when compared with non-terraced areas. Owing to characteristics such as deeper soils, more water capacity, lower salinity and less sodic soils, terraced soils provide better conditions for passive restoration of both soil and vegetation. Therefore, the recovery and maintenance of wall structures and revegetation with native/endemic species are proposed to promote the restoration of native systems and preserve a landscape with cultural and aesthetic value.

  8. Selaginella moellendoffii telomeres: conserved and unique features in an ancient land plant lineage

    Eugene V Shakirov

    2012-07-01

    Full Text Available Telomeres, the essential terminal regions of linear eukaryotic chromosomes, consist of G-rich DNA repeats bound by a plethora of associated proteins. While the general pathways of telomere maintenance are evolutionarily conserved, individual telomere complex components show remarkable variation between eukaryotic lineages and even within closely related species. The recent genome sequencing of the lycophyte Selaginella moellendoffii and the availability of an ever-increasing number of flowering plant genomes provides a unique opportunity to evaluate the molecular and functional evolution of telomere components from the early evolving non-seed plants to the more developmentally advanced angiosperms. Here we analyzed telomere sequence in S. moellendorffii and found it to consist of TTTAGGG repeats, typical of most plants. Telomere tracts in S. moellendorffii range from 1-5.5 kb, closely resembling Arabidopsis thaliana. We identified several S. moellendorffii genes encoding sequence homologues of proteins involved in telomere maintenance in other organisms, including CST complex components and the telomere-binding proteins POT1 and TRFL. Notable sequence similarities and differences were uncovered among the telomere-related genes in some of the plant lineages. Taken together, the data indicate that comparative analysis of the telomere complex in early diverging land plants such as S. moellendorffii and green algae will yield important insights into the evolution of telomeres and their protein constituents.

  9. Testing the stress-gradient hypothesis during the restoration of tropical degraded land using the shrub Rhodomyrtus tomentosa as a nurse plant

    Nan Liu; Hai Ren; Sufen Yuan; Qinfeng Guo; Long Yang

    2013-01-01

    The relative importance of facilitation and competition between pairwise plants across abiotic stress gradients as predicted by the stress-gradient hypothesis has been confirmed in arid and temperate ecosystems, but the hypothesis has rarely been tested in tropical systems, particularly across nutrient gradients. The current research examines the interactions between a...

  10. Estimation of water pollution by domestic in-land nuclear power plant under severe accident

    Li Hong; Fang Sheng; Fang Dong

    2013-01-01

    In-land nuclear power plant sites of China are usually located in densely populated area and are close to large surface water. This paper proposed scenarios and corresponding calculation models for water contamination caused by radioactive plume release after a severe accident. The models were applied to an imaginary lake (reservoir)-adjacent site in the south of China. The results showed that, the short-time concentration of radioactivity in the lake due to dry and wet deposition and runoff was higher than the generic action levels for foodstuffs in GB 18871-2002, and the public dose resulted was unacceptable. (authors)

  11. Restoring crop productivity of eroded lands through , integrated plant nutrient management (IPNM) for sustained production

    Bhatti, A.U.; Ali, S.

    2005-01-01

    Crop productivity of eroded lands is very poor due to removal of top fertile soil losing organic matter and plant nutrients, with consequent exposure of the sub-soil with poor fertility status. Crop productivity of such lands needs to be restored in order to help farmers feed many mouths because of increased population and high land pressure. Three field experiments were laid out at three sites, Thana, Malakand Agency; Kabal and Matta, Swat during 2003-2004 to study the effect of integrated plant nutrient management on the yield of wheat. The fertilizer treatments consisted of farmer's practice (60-45-0 kg N-P/sub 2/O/sub 5/-K/sub 2/O ha/sup -1/), recommended fertilizer rate (120-90-60 kg N-P/sub 2/O/sub 5/-K/sub 2/O ha/sup -l/ + 5 kg Zn ha/sup -1), and combined application of organic and inorganic sources of plant nutrients (FYM at the rate of 20 t ha/sup -1/ plus 60-90-60 kg N-P/sub 2/O/sub 5/-K/sub 2/O ha/sup -1/ + 5 kg Zn ha/sup -1/). The results obtained from these field trails showed that the combined application of FYM with NPK Zn increased the grain yield significantly over the other two treatments with an increase of 50-80% over the farmer's practice and 11 to 23 % over the recommended dose. As regards straw yields, T/sub 2/ and T/sub 3/ increased the yields significantly over farmer's practice (T) at all the sites; However, T/sub 2/ and T/sub 3/ at Thana and Kabal were at par with each other. As regards effect of various treatments on soil properties, organic matter content was improved at Thana and Kabal sites while at Matta the results were inconsistent. Similarly soil P and Zn contents were increased considerably in T/sub 2/ and T/sub 3/ at Thana and Kabal being at par with each other. It is apparent from these results that the crop productivity of eroded lands at all the three sties was considerably restored and the soil fertility status was improved by integrated plant nutrient management. (author)

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

    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

  13. Algae from the arid southwestern United States: an annotated bibliography

    Thomas, W.H.; Gaines, S.R.

    1983-06-01

    Desert algae are attractive biomass producers for capturing solar energy through photosynthesis of organic matter. They are probably capable of higher yields and efficiencies of light utilization than higher plants, and are already adapted to extremes of sunlight intensity, salinity and temperature such as are found in the desert. This report consists of an annotated bibliography of the literature on algae from the arid southwestern United States. It was prepared in anticipation of efforts to isolate desert algae and study their yields in the laboratory. These steps are necessary prior to setting up outdoor algal culture ponds. Desert areas are attractive for such applications because land, sunlight, and, to some extent, water resources are abundant there. References are sorted by state.

  14. Phthalate esters contamination in soil and plants on agricultural land near an electronic waste recycling site.

    Ma, Ting Ting; Christie, Peter; Luo, Yong Ming; Teng, Ying

    2013-08-01

    The accumulation of phthalic acid esters (PAEs) in soil and plants in agricultural land near an electronic waste recycling site in east China has become a great threat to the neighboring environmental quality and human health. Soil and plant samples collected from land under different utilization, including fallow plots, vegetable plots, plots with alfalfa (Medicago sativa L.) as green manure, fallow plots under long-term flooding and fallow plots under alternating wet and dry periods, together with plant samples from relative plots were analyzed for six PAE compounds nominated as prior pollutants by USEPA. In the determined samples, the concentrations of six target PAE pollutants ranged from 0.31-2.39 mg/kg in soil to 1.81-5.77 mg/kg in various plants (dry weight/DW), and their bioconcentration factors (BCFs) ranged from 5.8 to 17.9. Health risk assessments were conducted on target PAEs, known as typical environmental estrogen analogs, based on their accumulation in the edible parts of vegetables. Preliminary risk assessment to human health from soil and daily vegetable intake indicated that DEHP may present a high-exposure risk on all ages of the population in the area by soil ingestion or vegetable consumption. The potential damage that the target PAE compounds may pose to human health should be taken into account in further comprehensive risk assessments in e-waste recycling sites areas. Moreover, alfalfa removed substantial amounts of PAEs from the soil, and its use can be considered a good strategy for in situ remediation of PAEs.

  15. Agave: a biofuel feedstock for arid and semi-arid environments

    Gross, Stephen; Martin, Jeffrey; Simpson, June; Wang, Zhong; Visel, Axel

    2011-05-31

    Efficient production of plant-based, lignocellulosic biofuels relies upon continued improvement of existing biofuel feedstock species, as well as the introduction of newfeedstocks capable of growing on marginal lands to avoid conflicts with existing food production and minimize use of water and nitrogen resources. To this end, specieswithin the plant genus Agave have recently been proposed as new biofuel feedstocks. Many Agave species are adapted to hot and arid environments generally unsuitable forfood production, yet have biomass productivity rates comparable to other second-generation biofuel feedstocks such as switchgrass and Miscanthus. Agavesachieve remarkable heat tolerance and water use efficiency in part through a Crassulacean Acid Metabolism (CAM) mode of photosynthesis, but the genes andregulatory pathways enabling CAM and thermotolerance in agaves remain poorly understood. We seek to accelerate the development of agave as a new biofuelfeedstock through genomic approaches using massively-parallel sequencing technologies. First, we plan to sequence the transcriptome of A. tequilana to provide adatabase of protein-coding genes to the agave research community. Second, we will compare transcriptome-wide gene expression of agaves under different environmentalconditions in order to understand genetic pathways controlling CAM, water use efficiency, and thermotolerance. Finally, we aim to compare the transcriptome of A.tequilana with that of other Agave species to gain further insight into molecular mechanisms underlying traits desirable for biofuel feedstocks. These genomicapproaches will provide sequence and gene expression information critical to the breeding and domestication of Agave species suitable for biofuel production.

  16. Planning for closures of hazardous waste land disposal units at the Oak Ridge Y-12 plant

    Welch, S.H.; Kelly, B.A.; DeLozier, M.F.P.; Manrod, W.E.

    1988-01-01

    Eight hazardous waste land disposal units at the Oak Ridge Y-12 Plant are being closed in accordance with the Resource Conservation and Recovery Act (RCRA) under an integrated multi-year program. The units, some of which date back to the early 1950s and include five surface impoundments, two landfills and a land treatment unit, have been used for the management of a variety of types of hazardous wastes. Closure plans for the units have been submitted and are in various stages of revision and regulatory review. The units will be closed by various combinations of methods, including liquid removal and treatment, sludge stabilization, contaminated sludge and/or soil removal, and capping. Closure of all eight units must be initiated by November 8, 1988. Funding for the eight closures is being provided by a new Department of Energy budget category, the environmental Restoration Budget Category (ERBC), which is intended to allow for a more rapid response to environmental problems and regulatory requirements. A major project, Closure and Post-Closure Activities (CAPCA) has been identified for ERBC funding to close the land disposal units in accordance with RCRA requirements. Establishing the project scope has required the development of a detailed set of assumptions and a confirmation program for each assumption. Other significant activities in the CAPCA project include risk assessments and the preparation of an integrated project schedule

  17. Attempt for reconstruction of agricultural land in Fukushima using biofertilizer microorganisms and Ce-removing plants

    Yokoyama, Tadashi

    2016-01-01

    A group of microorganisms inhabiting the crop rhizosphere promote the absorption of nutrients of crops and helps improve their productivity. These are collectively referred to as biofertilizers. In Fukushima Prefecture, potassium is applied to suppress absorption of radioactive Cs into crops. As a technique to remove radioactive Cs from agricultural lands, the authors investigated whether the combinations of biofertilizer microorganisms with radioactive Cs-removing plants can promote the rooting of these plants and accelerate the removal rate of radioactive Cs contained in the soil. In the field test, the absorption promoting effect on radioactive Cs was recognized by the combination of 3 varieties of Komatsuna and Bacillus genus fertilizer. However, the absorption promotion effect on radioactive Cs was less than 1/10 of that of the model experiment, which suggested the soil factor that the soils in Nihonmatsu City contained vermiculite as clay minerals. Then, the authors conducted a pot test, where the biofertilizer microorganisms having potassium-dissolving bacteria capable of mobilizing the radioactive Cs fixed on vermiculite were applied. It was confirmed that the transfer of radioactive Cs to the plant roots was increased. The combination of filamentous fungus and Ce-removing plants will also be studied in the future. (A.O.)

  18. Interrelationships between soil cover and plant cover depending on land use

    Tiina Köster

    2013-05-01

    Full Text Available Interrelationships between soil cover and plant cover of normally developed (or postlithogenic mineral soils are analysed on the basis of four sampling soil groups. The four-link pedo-ecological sequence of analysed soils, rendzinas → brown soils → pseudopodzolic soils → gley-podzols, forms a representative cross section in relation to the normal mineral soils of Estonia. All groups differ substantially from each other in terms of soil properties (calcareousness, acidity, nutrition conditions, profile fabric and humus cover. The primary tasks of the research were (1 to elucidate the main pedo-ecological characteristics of the four soil groups and their suitability for plant cover, (2 to evaluate comparatively soils in terms of productivity, sustainability, biodiversity and environmental protection ability and (3 to analyse possibilities for ecologically sound matching of soil cover with suitable plant cover. On the basis of the same material, the influence of land-use change on humus cover (epipedon fabric, properties of the entire soil cover and soil–plant interrelationship were also analysed. An ecosystem approach enables us to observe particularities caused by specific properties of a soil type (species, variety in biological turnover and in the formation of biodiversity.

  19. An ancestral stomatal patterning module revealed in the non-vascular land plant Physcomitrella patens

    Chater, Caspar C.; Kamisugi, Yasuko

    2016-01-01

    The patterning of stomata plays a vital role in plant development and has emerged as a paradigm for the role of peptide signals in the spatial control of cellular differentiation. Research in Arabidopsis has identified a series of epidermal patterning factors (EPFs), which interact with an array of membrane-localised receptors and associated proteins (encoded by ERECTA and TMM genes) to control stomatal density and distribution. However, although it is well-established that stomata arose very early in the evolution of land plants, until now it has been unclear whether the established angiosperm stomatal patterning system represented by the EPF/TMM/ERECTA module reflects a conserved, universal mechanism in the plant kingdom. Here, we use molecular genetics to show that the moss Physcomitrella patens has conserved homologues of angiosperm EPF, TMM and at least one ERECTA gene that function together to permit the correct patterning of stomata and that, moreover, elements of the module retain function when transferred to Arabidopsis. Our data characterise the stomatal patterning system in an evolutionarily distinct branch of plants and support the hypothesis that the EPF/TMM/ERECTA module represents an ancient patterning system. PMID:27407102

  20. Mining the Agave Microbiome for adaptions to arid environments

    Coleman-Derr, Devin; Wojke, Tanja; North, Gretchen; Partida-Martinez, Laila; DeAngeli, Kristen; Clingenpeel, Scott; Gross, Stephen; Tringe, Susannah; Visel, Axel

    2013-03-25

    A major challenge facing the biofuels industry is the identification of high-yield plant feedstocks that can be cultivated with minimal resource inputs without competing for land and water supplies with existing food crops. Recent research has demonstrated that the Agave plant, cultivated in Mexico and Southwestern United States for the production of fiber and alcohol, meets these criteria1. Agaves grow on non-arable rocky soils in regions characterized by prolonged drought and extreme temperatures, due in part to physiological adaptions that prevent excess water-loss in arid environments2. Plant-microbial symbioses can play a role in helping plants adapt to heat and drought stress, increasing the accessibility of soil nutrients, or compete with plant pathogens3. Whether agaves have similar beneficial microbe interactions in their native environment is unknown. We aim to provide a comprehensive characterization of the Agave microbiome, with the goal of identifying specific community members that may contribute to Agave biotic and abiotic stress tolerance

  1. Immunomodulatory activity of extracts from Cordia superba Cham. and Cordia rufescens A. DC. (Boraginaceae), plant species native from Brazilian Semi-arid

    Costa,José Fernando Oliveira; David,Juceni P. L.; David,Jorge M.; Giulietti,Ana M.; Queiroz,Luciano P.; Santos,Ricardo R.; Soares,Milena Botelho P.

    2008-01-01

    The family Boraginaceae is widely distributed in Brazil and in the Northeastern region some species are popularly used to treat symptoms of rheumatism, painful menstruation and dyspepsia. In this work we studied Cordia superba Cham. and C. rufescens A. DC., native from Brazilian Semi-arid region, in order to investigate their immunomodulatory activity. Six extracts were prepared from aerial parts of C. superba and C. rufescens. The cytotoxicity was evaluated using splenocytes from BALB/c mice...

  2. The Rise of Flowering Plants and Land Surface Physics: The Cretaceous and Eocene Were Different

    Upchurch, G. R.; Feild, T.

    2010-12-01

    The Cretaceous and Eocene have served as the poster children of past greenhouse climates. One difference between the two time periods is that angiosperms (flowering plants) underwent a major diversification and rise to dominance during the mid-Cretaceous to Paleocene. Flowering plants differ from all other living and fossil plants in having significantly higher rates of transpiration and photosynthesis, which in modern leaves correlate with the density of venation (Dv), a feature that can be measured directly from fossils. This increase in Dv, coupled with an increase in the abundance of angiosperms, is thought to have had major impact on the climate system. This is, in part, because transpiration plays an important role in determining the ratio of sensible to latent heat flux from the land surface and in determining precipitation rate in regions such as the equatorial rainforest. Analysis of Dv in fossil leaves indicates two phases of increase in transpiration rate for angiosperms during the Cretaceous-Paleocene. The oldest known angiosperms (Aptian-early Albian) have a low Dv characteristic of extant and fossil ferns and gymnosperms. At this time angiosperms are low-stature plants of minor importance in terms of relative abundance and diversity (ferns, and maximum Dv reaches levels characteristic of many trees from the temperate zone. This first phase coincides with the first local dominance of angiosperms, the first occurrence of moderate to large angiosperm trees (up to 1 m in diameter) , and the first common occurrence of angiosperms in the Arctic. The second phase of Dv increase occurs during the Maastrichtian to Paleocene, where average Dv reaches levels characteristic of modern tropical forests and maximum Dv reaches the level found in highly productive modern vegetation. This second phase coincides with the rise to dominance of angiosperms in regional vegetation, a corresponding decline of conifers and ferns, and the modernization of hydraulic architecture

  3. Patchiness in semi-arid dwarf shrublands: evidence from satellite ...

    ... Plants; Remote sensing; Rhigozum obovatum Burch; Satellite-derived vegetation indices; Woody species; patchiness; semi-arid; dwarf shrubland; shrublands; co2; assimilation; karoo; south africa; ndvi; satellite imagery; geochemical mound; rhigozum obovatum; eriocephalus ericoides; pentzia incana; vegetation; botany

  4. A methodology for small scale rural land use mapping in semi-arid developing countries using orbital imagery. Part 4: Review of land use surveys using orbital imagery outside of the USA

    Vangenderen, J. L. (Principal Investigator); Lock, B. F.

    1976-01-01

    The author has identified the following significant results. Outside the U.S., various attempts were made to investigate the feasibility of utilizing orbital MSS imagery in the production of small scale land use maps. Overall, these studies are not as elaborate or extensive in their scope as the U.S. ones, and generally the non-U.S. investigators have employed nonsophisticated and less expensive techniques. A representative range of studies is presented to demonstrate the approaches and trends dealing with reprocessing, interpretation, classification, sampling, and ground truth procedures.

  5. Land-Use and Socioeconomic Change, Medicinal Plant Selection and Biodiversity Resilience in Far Western Nepal

    Baral, Kedar; Paudel, Prashant; Acharya, Ram P.; Thapa-Magar, Khum B.; Cameron, Mary; Bussmann, Rainer W.

    2016-01-01

    Indigenous plant use-systems have evolved under, and constantly adapted to human and non-human impacts. In the last decades however, increasing socioeconomic and cultural transformations, including land-use change, outmigration, globalized markets, the introduction of new species, and climate change have led to a decreasing availability of indigenous resources, and are ultimately leading to a reduction of local use-knowledge. Participant observations, discussions, walks-in-the-woods, semi-structured interviews and informal meetings were carried out in 12 villages of far western Nepal between 2011 and 2015 to assess how sociocultural changes have affected the sustenance of indigenous systems and local biodiversity, when compared to studies carried out in the previous decades. Our findings show that there were no statistically significant differences in subject variable means, but differences were relatively important to plant parts-use and plant growth-forms (p = 0.183 and 0.088 respectively). Cissampelos pareira, Acorus calamus, Calotropis gigantea were found to have the greatest relative importance, whereas Ageratina adenophora, Melia azedarach, Carum carvi were most important based on use values. Among them, C. pareira and A. adenophora were introduced. The spatial distribution of species collected for medicine showed that all habitats were important for collection however, habitats close to villages were more favored. The use of non-indigenous and easily available species and more accessible habitats is becoming more prevalent as primary forests become increasingly overexploited, indigenous species become limited, and sociocultural cause of land use change expand. The utilization of indigenous and non-indigenous species and nearby habitats, although possibly affecting the quality of medicinal species, nonetheless reveals the dynamism of indigenous medicines as an adaptive asset mitigating human and non-human environmental changes. PMID:27936247

  6. Land-Use and Socioeconomic Change, Medicinal Plant Selection and Biodiversity Resilience in Far Western Nepal.

    Kunwar, Ripu M; Baral, Kedar; Paudel, Prashant; Acharya, Ram P; Thapa-Magar, Khum B; Cameron, Mary; Bussmann, Rainer W

    2016-01-01

    Indigenous plant use-systems have evolved under, and constantly adapted to human and non-human impacts. In the last decades however, increasing socioeconomic and cultural transformations, including land-use change, outmigration, globalized markets, the introduction of new species, and climate change have led to a decreasing availability of indigenous resources, and are ultimately leading to a reduction of local use-knowledge. Participant observations, discussions, walks-in-the-woods, semi-structured interviews and informal meetings were carried out in 12 villages of far western Nepal between 2011 and 2015 to assess how sociocultural changes have affected the sustenance of indigenous systems and local biodiversity, when compared to studies carried out in the previous decades. Our findings show that there were no statistically significant differences in subject variable means, but differences were relatively important to plant parts-use and plant growth-forms (p = 0.183 and 0.088 respectively). Cissampelos pareira, Acorus calamus, Calotropis gigantea were found to have the greatest relative importance, whereas Ageratina adenophora, Melia azedarach, Carum carvi were most important based on use values. Among them, C. pareira and A. adenophora were introduced. The spatial distribution of species collected for medicine showed that all habitats were important for collection however, habitats close to villages were more favored. The use of non-indigenous and easily available species and more accessible habitats is becoming more prevalent as primary forests become increasingly overexploited, indigenous species become limited, and sociocultural cause of land use change expand. The utilization of indigenous and non-indigenous species and nearby habitats, although possibly affecting the quality of medicinal species, nonetheless reveals the dynamism of indigenous medicines as an adaptive asset mitigating human and non-human environmental changes.

  7. Future aridity under conditions of global climate change

    Asadi Zarch, Mohammad Amin; Sivakumar, Bellie; Malekinezhad, Hossein; Sharma, Ashish

    2017-11-01

    Global climate change is anticipated to cause some major changes in hydroclimatic conditions around the world. As aridity is a reliable indicator of potential available water, assessment of its changes under future climatic conditions is important for proper management of water. This study employs the UNESCO aridity/humidity index, which is a derivative of precipitation (P) and potential evapotranspiration (PET), for assessment of aridity. Historical (1901-2005) simulations and future (2006-2100) projections of 22 global climate models (GCMs) from the fifth phase of the Coupled Model Intercomparison Project (CMIP5) are studied. The Nested Bias Correction (NBC) approach is used to correct possible biases of precipitation (simulated directly by the GCMs) and PET (estimated by applying FAO56-Penman-Monteith model on simulated parameters of the GCMs). To detect future aridity changes, the areal extents of the aridity zones in the past and future periods as well as through four sub-periods (2006-2025, 2026-2050, 2051-2075, and 2076-2100) of the future are compared. The results indicate that changes in climate will alter the areal extents of aridity zones in the future. In general, from the first sub-period towards the last one, the area covered by hyper-arid, arid, semi-arid, and sub-humid zones will increase (by 7.46%, 7.01%, 5.80%, and 2.78%, respectively), while the area of the humid regions will decrease (by 4.76%), suggesting that there will be less water over the global land area in the future. To understand the cause of these changes, precipitation and PET are also separately assumed to be stationary throughout the four future sub-periods and the resulting aridity changes are then analyzed. The results reveal that the aridity changes are mostly caused by the positive PET trends, even though the slight precipitation increase lessens the magnitude of the changes.

  8. Laboratory observations on the larvicidal efficacy of three plant species against mosquito vectors of malaria, dengue/dengue hemorrhagic fever (DF/DHF) and lymphatic filariasis in the semi-arid desert.

    Bansal, S K; Singh, Karam V; Sharma, Sapna; Sherwani, M R K

    2012-05-01

    Comparative larvicidal efficacy of aqueous and organic solvent extracts from seeds, leaves and flowers of three desert plants viz. Calotropis procera (Aiton), Tephrosia purpurea (L.) Pers. and Prosopis juliflora (Sw.) DC. was evaluated against Anopheles stephensi (Liston), Aedes aegypti (Linnaeus) and Culex quinquefasciatus (Say). For this purpose larvae of all the three mosquito species were reared in the laboratory and studies carried out on late 3rd or early 4th instars using standard WHO technique. Based on concentration mortality data 24 and 48 hr LC50and LC90 values along with their 95% fiducial limits, regression equation, chi-square (chi2)/ heterogeneity of the response were determined by log probit regression analysis. Experiments were carried out with different solvent extracts of seeds of C. procera which revealed that methanol (24 hr LC50: 127.2, 194.8, 361.0) and acetone (229.9, 368.1,193.0 mg l(-1)) extracts were more effective with the three mosquito species, respectively. Petroleum ether extract was effective only on An. stephensi while aqueous extracts were not effective at all with any of the mosquito species (mortality juliflora were 74.9, 63.2 and 47.0 and 96.2,128.1 and 118.8 mg l(-1) for the above three mosquito species, respectively. Experiments carried out up to 500 mg l-(1) with leaves (T. purpurea) and seeds (P. juliflora) extracts show only up to 10-30% mortality indicating that active larvicidal principle may be present only in the seeds of Tephrosia and leaves of Prosopis. In general, anophelines were found more susceptible than the culicines to the plant derived derivatives. More studies are being carried outon some other desert plants found in this arid region. The study would be of great importance while formulating vector control strategy based on alternative plant based insecticides in this semi-arid region.

  9. Phylogenomic Analyses Indicate that Early Fungi Evolved Digesting Cell Walls of Algal Ancestors of Land Plants

    Chang, Ying; Wang, Sishuo; Sekimoto, Satoshi; Aerts, Andrea L.; Choi, Cindy; Clum, Alicia; LaButti, Kurt M.; Lindquist, Erika A.; Yee Ngan, Chew; Ohm, Robin A.; Salamov, Asaf A.; Grigoriev, Igor V.; Spatafora, Joseph W.; Berbee, Mary L.

    2015-01-01

    As decomposers, fungi are key players in recycling plant material in global carbon cycles. We hypothesized that genomes of early diverging fungi may have inherited pectinases from an ancestral species that had been able to extract nutrients from pectin-containing land plants and their algal allies (Streptophytes). We aimed to infer, based on pectinase gene expansions and on the organismal phylogeny, the geological timing of the plant–fungus association. We analyzed 40 fungal genomes, three of which, including Gonapodya prolifera, were sequenced for this study. In the organismal phylogeny from 136 housekeeping loci, Rozella diverged first from all other fungi. Gonapodya prolifera was included among the flagellated, predominantly aquatic fungal species in Chytridiomycota. Sister to Chytridiomycota were the predominantly terrestrial fungi including zygomycota I and zygomycota II, along with the ascomycetes and basidiomycetes that comprise Dikarya. The Gonapodya genome has 27 genes representing five of the seven classes of pectin-specific enzymes known from fungi. Most of these share a common ancestry with pectinases from Dikarya. Indicating functional and sequence similarity, Gonapodya, like many Dikarya, can use pectin as a carbon source for growth in pure culture. Shared pectinases of Dikarya and Gonapodya provide evidence that even ancient aquatic fungi had adapted to extract nutrients from the plants in the green lineage. This implies that 750 million years, the estimated maximum age of origin of the pectin-containing streptophytes represents a maximum age for the divergence of Chytridiomycota from the lineage including Dikarya. PMID:25977457

  10. A review of public desert land lease policies for concentrated solar power plants and the impact on their economic performance

    Smyrnakis, Christos; Phocas-Cosmetatos, Alex; Kynigalakis, Kostantinos

    2016-05-01

    Large scale Concentrated Solar Power (CSP) plants need large plots of land with very high solar resource and thus are often deployed in desert areas which are usually owned by the state or a municipal authority. This study discusses the implication and practices of land lease policies with regards to CSP development. The strategy followed on a land lease is examined by definition on a case-specific basis and this text is by no means exhaustive with regards to its content. The study also discusses the pricing of land in various cases, presents the governing types of land lease and their effect on the economic performance of hypothetical CSP projects under various cases.

  11. A horizontal gene transfer at the origin of phenylpropanoid metabolism: a key adaptation of plants to land.

    Emiliani, Giovanni; Fondi, Marco; Fani, Renato; Gribaldo, Simonetta

    2009-02-16

    The pioneering ancestor of land plants that conquered terrestrial habitats around 500 million years ago had to face dramatic stresses including UV radiation, desiccation, and microbial attack. This drove a number of adaptations, among which the emergence of the phenylpropanoid pathway was crucial, leading to essential compounds such as flavonoids and lignin. However, the origin of this specific land plant secondary metabolism has not been clarified. We have performed an extensive analysis of the taxonomic distribution and phylogeny of Phenylalanine Ammonia Lyase (PAL), which catalyses the first and essential step of the general phenylpropanoid pathway, leading from phenylalanine to p-Coumaric acid and p-Coumaroyl-CoA, the entry points of the flavonoids and lignin routes. We obtained robust evidence that the ancestor of land plants acquired a PAL via horizontal gene transfer (HGT) during symbioses with soil bacteria and fungi that are known to have established very early during the first steps of land colonization. This horizontally acquired PAL represented then the basis for further development of the phenylpropanoid pathway and plant radiation on terrestrial environments. Our results highlight a possible crucial role of HGT from soil bacteria in the path leading to land colonization by plants and their subsequent evolution. The few functional characterizations of sediment/soil bacterial PAL (production of secondary metabolites with powerful antimicrobial activity or production of pigments) suggest that the initial advantage of this horizontally acquired PAL in the ancestor of land plants might have been either defense against an already developed microbial community and/or protection against UV.

  12. A horizontal gene transfer at the origin of phenylpropanoid metabolism: a key adaptation of plants to land

    Gribaldo Simonetta

    2009-02-01

    Full Text Available Abstract Background The pioneering ancestor of land plants that conquered terrestrial habitats around 500 million years ago had to face dramatic stresses including UV radiation, desiccation, and microbial attack. This drove a number of adaptations, among which the emergence of the phenylpropanoid pathway was crucial, leading to essential compounds such as flavonoids and lignin. However, the origin of this specific land plant secondary metabolism has not been clarified. Results We have performed an extensive analysis of the taxonomic distribution and phylogeny of Phenylalanine Ammonia Lyase (PAL, which catalyses the first and essential step of the general phenylpropanoid pathway, leading from phenylalanine to p-Coumaric acid and p-Coumaroyl-CoA, the entry points of the flavonoids and lignin routes. We obtained robust evidence that the ancestor of land plants acquired a PAL via horizontal gene transfer (HGT during symbioses with soil bacteria and fungi that are known to have established very early during the first steps of land colonization. This horizontally acquired PAL represented then the basis for further development of the phenylpropanoid pathway and plant radiation on terrestrial environments. Conclusion Our results highlight a possible crucial role of HGT from soil bacteria in the path leading to land colonization by plants and their subsequent evolution. The few functional characterizations of sediment/soil bacterial PAL (production of secondary metabolites with powerful antimicrobial activity or production of pigments suggest that the initial advantage of this horizontally acquired PAL in the ancestor of land plants might have been either defense against an already developed microbial community and/or protection against UV. Reviewers This article was reviewed by Purificación López-García, Janet Siefert, and Eugene Koonin.

  13. The polyphenol oxidase gene family in land plants: Lineage-specific duplication and expansion

    Tran Lan T

    2012-08-01

    Full Text Available Abstract Background Plant polyphenol oxidases (PPOs are enzymes that typically use molecular oxygen to oxidize ortho-diphenols to ortho-quinones. These commonly cause browning reactions following tissue damage, and may be important in plant defense. Some PPOs function as hydroxylases or in cross-linking reactions, but in most plants their physiological roles are not known. To better understand the importance of PPOs in the plant kingdom, we surveyed PPO gene families in 25 sequenced genomes from chlorophytes, bryophytes, lycophytes, and flowering plants. The PPO genes were then analyzed in silico for gene structure, phylogenetic relationships, and targeting signals. Results Many previously uncharacterized PPO genes were uncovered. The moss, Physcomitrella patens, contained 13 PPO genes and Selaginella moellendorffii (spike moss and Glycine max (soybean each had 11 genes. Populus trichocarpa (poplar contained a highly diversified gene family with 11 PPO genes, but several flowering plants had only a single PPO gene. By contrast, no PPO-like sequences were identified in several chlorophyte (green algae genomes or Arabidopsis (A. lyrata and A. thaliana. We found that many PPOs contained one or two introns often near the 3’ terminus. Furthermore, N-terminal amino acid sequence analysis using ChloroP and TargetP 1.1 predicted that several putative PPOs are synthesized via the secretory pathway, a unique finding as most PPOs are predicted to be chloroplast proteins. Phylogenetic reconstruction of these sequences revealed that large PPO gene repertoires in some species are mostly a consequence of independent bursts of gene duplication, while the lineage leading to Arabidopsis must have lost all PPO genes. Conclusion Our survey identified PPOs in gene families of varying sizes in all land plants except in the genus Arabidopsis. While we found variation in intron numbers and positions, overall PPO gene structure is congruent with the phylogenetic

  14. Migration studies at the Savannah River Plant shallow land burial site

    Stone, J.A.; Oblath, S.B.; Hawkins, R.H.; Emslie, R.H.; Ryan, J.P. Jr.; King, C.M.

    1983-01-01

    Radionuclide migration from the Savannah River Plant low-level waste burial ground was studied in ongoing programs that provide generic data on a shallow land burial site in a humid region and support local waste disposal operations. Field, laboratory, and theoretical work continued in four areas. (1) Subsurface Monitoring: Groundwater around the burial ground was monitored for traces of radioactivity and mercury. (2) Lysimeter Tests: Gamma-emitting radionuclides were identified by sensitive methods in defense waste lysimeter percolate waters. Results from these and other lysimeters containing tritium, I-129, or Pu-239 sources are given. (3) Soil-Water Chemistry: Experiments on specific factors affecting migration of Cs-137 showed that potassium significantly increases cesium mobility, thus confirming observations with trench waters. Distribution coefficients for ruthenium were measured. (4) Transport Modeling: Efforts to refine and validate the SRL dose-to-man model continued. Transport calculations were made for tritium, Sr-90, Tc-99, and TRU radionuclides. 12 references, 3 tables

  15. Trace elements in land plants: concentration ranges and accumulators of rare earths, Ba, Ra, Mn, Fe, Co and heavy halogens

    Koyama, M.; Shirakawa, M.; Takada, J.; Katayama, Y.; Matsubara, T.

    1987-01-01

    More than 2000 samples of land plant leaves, mostly of tree, were analyzed by neutron activation analysis in order to find out macroscopic relations between distributions of chemical elements in plants and soil characteristics. The distributions of the elements in plants were also examined from the view point of botanical taxonomy or phylogeny. New species which accumulate Co, rare earths, Ba, Ra, heavy halogens and some other elements were found. Capability or potentiality for accumulating elements could be related to higher ranks of taxonomy, that is, genus or family. The nature of soil is also found to have profound effects on the extent of accumulation of elements in plants. (author)

  16. Environment Quality: Impact From Traffic, Power Plant and Land Morphology, a Case Study of Prishtina

    Bajcinovci, Bujar

    2017-05-01

    Environmental air pollution is a global health concern, a complex phenomenon which is directly reflected on public health, economic and human development. Environmental air pollution has been drastically multiplied, followed by the beginning of the new Millennia in Prishtina, the capital city of the Kosovo. The new millennium began as a crucial activity for the city of Prishtina in terms of demographic, human geography, social and economic phenomena. The presented study aims to determine prevalent traffic and land morphology composition attributes, which have influenced and continue to have environmental impact in the city of Prishtina. According to the conceptual findings from the empirical observations, the heavy city traffic and the land morphology structure, determine the urban air pollution level. Prishtina is generally polluted due to its geomorphic position in relation to the power plants Kosovo A, and Kosova B. The impact of the above cited factors, is even bigger when the dominant winds prevail through valley, which encompasses the city. The findings from this paper propose the necessity of careful driven urban solutions.

  17. Environment Quality: Impact From Traffic, Power Plant and Land Morphology, a Case Study of Prishtina

    Bajcinovci Bujar

    2017-05-01

    Full Text Available Environmental air pollution is a global health concern, a complex phenomenon which is directly reflected on public health, economic and human development. Environmental air pollution has been drastically multiplied, followed by the beginning of the new Millennia in Prishtina, the capital city of the Kosovo. The new millennium began as a crucial activity for the city of Prishtina in terms of demographic, human geography, social and economic phenomena. The presented study aims to determine prevalent traffic and land morphology composition attributes, which have influenced and continue to have environmental impact in the city of Prishtina. According to the conceptual findings from the empirical observations, the heavy city traffic and the land morphology structure, determine the urban air pollution level. Prishtina is generally polluted due to its geomorphic position in relation to the power plants Kosovo A, and Kosova B. The impact of the above cited factors, is even bigger when the dominant winds prevail through valley, which encompasses the city. The findings from this paper propose the necessity of careful driven urban solutions.

  18. RCRA land unit closures at the Y-12 Plant, Oak Ridge, Tennessee

    Welch, S.H.; Kelly, B.A.; Delozier, M.F.P.; Manrod, W.E.

    1987-01-01

    Eight land-based hazardous waste management units at the Y-12 Plant are being closed under an integrated multi-year program. Closure plans for the units have been submitted and are in various stages of revision and regulatory review. These units will be closed by various combinations of methods, including liquid removal and treatment, sludge stabilization, contaminated sludge and/or soil removal, and capping. The closure of these sites will be funded by a new Department of Energy budget category, the Environmental Restoration Budget Category (ERBC), which is intended to provide greater flexibility in the response to closure and remedial activities. A major project, Closure and Post-Closure Activities (CAPCA), has been identified for ERBC funding to close and remediate the land units in accordance with RCRA requirements. Establishing the scope of this program has required the development of a detailed set of assumptions and a confirmation program for each assumption. Other significant activities in the CAPCA program include the development of risk assessments and the preparation of an integrated schedule

  19. Stakeholder Perceptions of an Ecosystem Services Approach to Clearing Invasive Alien Plants on Private Land

    Lauren S. Urgenson

    2013-03-01

    Full Text Available Incentivizing private landowners and other stakeholders is central to the effective conservation of ecosystem services in working landscapes. To better understand how to design effective incentives, the perceptions of landowners and other stakeholders are explored regarding a proposed approach to clearing invasive alien plants on private land in the Western Cape Province, South Africa. The public funded national program, Working for Water, conserves ecosystem services while employing and training people from marginalized sectors of society to clear these plants. Private landowner involvement is a key conservation challenge, because without adequate landowner involvement, invasive alien plants persist on the landscape and continuously reinvade cleared areas. We collected interview data from private landowners in three study sites, and web-survey data from conservation professionals and Working for Water managers, in order to compare stakeholder perceptions of (1 government and landowners' responsibilities for clearing invasive alien plants; (2 existing and proposed policy tools; and (3 the extent to which stakeholders consider the proposed financial incentive to be sufficient. There was significant consensus among stakeholders concerning their preference for shared landowner and government responsibility and for a policy mix that combines incentives with disincentives. Landowners from the three study sites differed in the level of responsibility they were willing to assume. Stakeholders also diverged in terms of their perceptions of the proposed financial incentives. Furthermore, the perspectives of landowners were strongly associated with ecological and social features of the landscapes in which they are located. Understanding stakeholders' points of view within their differing contexts is shown to be a valuable means of gaining insight into the opportunities and constraints that face ecosystem service conservation in working landscapes.

  20. The challenges of rehabilitating denuded patches of a semi-arid environment in Kenya

    Mganga, K.Z.; Nyangito, M.M.; Musimba, N.K.R.; Nyariki, D.M.; Mwangombe, A.W.; Ekaya, W.N.; Muiri, W.M.; Clavel, D.; Francis, J.; Kaufmann, Von R.; Verhagen, J.

    2010-01-01

    Land degradation is a major problem in the semi-arid environments of Sub-Saharan Africa. Fighting land degradation is essential to ensure the sustainable and long-term productivity of the habited semiarid lands. In Kenya, grass reseeding technology has been used to combat land degradation. However,

  1. Shallow land burial technology development - arid

    DePoorter, G.L.; Abeele, W.V.; Burton, B.W.; Hakonson, T.E.; Perkins, B.A.

    1982-01-01

    The experimental results obtained during FY-1982 on biointrusion barrier testing, migration barrier testing, and ground and surface water management system testing are described. The results of the small lysimeter study on biointrusion barriers are presented and the larger scale experiments in progress are described. The results of the experiments to determine the migration potential for water under unsaturated conditions are described. Preliminary results on the wick system experiment are presented. A comparison of model calculations and experimental results on the water movement experiments is also presented

  2. The net effect of abiotic conditions and biotic interactions in a semi-arid ecosystem NE Spain: implications for the management and restoration.

    Pueyo, Yolanda; Arroyo, Antonio I.; Saiz, Hugo; Alados, Concepción L.

    2014-05-01

    Degradation in arid and semiarid lands can be irreversible without human intervention, due to a positive plant-soil feedback where the loss of vegetation cover leads to soil degradation, which in turn hampers plant establishment. Human intervention in restoration actions usually involves the amendment of the degraded abiotic conditions, revegetation of bare areas, or both. However, abiotic amelioration is often expensive and too intrusive, and revegetation is not successful in many cases. Biotic interactions between plants, and more specifically facilitation by a "nurse" plant, have been proposed as a new via to take profit of improved abiotic conditions without intervention, and to increase the success rate of revegetation actions. But "nurse" plants can also interfere with others (i.e. by competition for resources or the release of allelopathic compounds), and the net balance between facilitation and interference could depend on plant types involved. We present recent observational and experimental studies performed in the semiarid ecosystems of the Middle Ebro Valley (NE Spain) about the role of abiotic conditions and biotic interactions in the productivity, dynamics and diversity of plant communities under different stress conditions (aridity and grazing). We found that all plant types studied (shrubs and perennial grasses) improved abiotic conditions (soil temperature and water availability for plants) with respect to open areas. However, only some shrubs (mainly Salsola vermiculata) had a positive net balance in the biotic interactions between plants, while other shrubs (Artemisia herba-alba) and perennial grasses (Lygeum spartum) showed interference with other plants. Moreover, the net balance between facilitation and interference among plants in the community shifted from competitive to neutral or from neutral to facilitative with increasing aridity. Grazing status did not strongly change the net biotic interactions between plants. Our results suggest that

  3. Origin and Evolution of The Early- Silurian Land Vascular Plants: Evidence From Biomarkers

    Jin, R.

    2016-12-01

    Origin and early evolution of land vascular plants, is one of the most intriguing hotspots in the life science research. During the 1970s and 1980s,Pinnatiramosus qianensis was found in early-Silurian strata in guizhou of south China.43 years have passed. But so far, the biological characteristics and belonging of the age of this unique plant have been debated again and again, up in the air.Biomarkers have a good stability in the process of organic evolution, no more or less changed, so they have a special `function of mark'. While biomarkers can provide information about organic matter of hydrocarbon source rock (the source), the period of deposition and burial (diagenesis) environmental conditions, and many other aspects of information.This paper obtained the sedimentary environment, source of organic matter input and other relevant information, through extracting and analyzing biomarkers of the 26 samples in the late Ordovician to early Silurian strata in NorthGuizhou areas. According to the results, Pr/Ph of late Ordovician Meitan Fm-early Silurian Hanjiadian Fm is high.It manifests more pristane, characterized by reductive environment. At the bottom of the Hanjiadian Fm, Pr/Ph has a volatility.Some huge environmental changes may have taken place in the corresponding period. N-alkanes do not have parity advantage or has even carbon advantage slightly.The peak carbon is mainly in low carbon number.(C21 + C22)/(C28 + C29) is high.Aquatic organisms is a major source of organic matter during this period,C21-/C22+ is low.This may be caused by the relatively serious loss of light hydrocarbon during the separation of components. In the Hanjiadian Fm,information of C29/C27 sterane ratios and oleanane index showed a trend of rising at the same time, indicating that during this period, there was a gradual increase input in the number of higher plants.The stable carbon isotope of saturated hydrocarbon and aromatic hydrocarbon in the Hanjiadian Fm also gradually become

  4. Aridity and grazing as convergent selective forces: an experiment with an Arid Chaco bunchgrass.

    Quiroga, R Emiliano; Golluscio, Rodolfo A; Blanco, Lisandro J; Fernández, Roberto J

    2010-10-01

    It has been proposed that aridity and grazing are convergent selective forces: each one selects for traits conferring resistance to both. However, this conceptual model has not yet been experimentally validated. The aim of this work was to experimentally evaluate the effect of aridity and grazing, as selective forces, on drought and grazing resistance of populations of Trichloris crinita, a native perennial forage grass of the Argentinean Arid Chaco region. We collected seeds in sites with four different combinations of aridity and grazing history (semiarid/ subhumid x heavily grazed/lightly grazed), established them in pots in a common garden, and subjected the resulting plants to different combinations of drought and defoliation. Our results agreed with the convergence model. Aridity has selected T. crinita genotypes that respond better to drought and defoliation in terms of sexual reproduction and leaf growth, and that can evade grazing due to a lower shoot: root ratio and a higher resource allocation to reserves (starch) in stem bases. Similarly, grazing has selected genotypes that respond better to drought and defoliation in terms of sexual reproduction and that can evade grazing due to a lower digestibility of leaf blades. These results allow us to extend concepts of previous models in plant adaptation to herbivory to models on plant adaptation to drought. The only variable in which we obtained a result opposite to predictions was plant height, as plants from semiarid sites were taller (and with more erect tillers) than plants from subhumid sites; we hypothesize that this result might have been a consequence of the selection exerted by the high solar radiation and soil temperatures of semiarid sites. In addition, our work allows for the prediction of the effects of dry or wet growing seasons on the performance of T. crinita plants. Our results suggest that we can rely on dry environments for selecting grazing-resistant genotypes and on high grazing pressure

  5. Distribution of trace elements in land plants and botanical taxonomy with special reference to rare earth elements and actinium

    Koyama, Mutsuo

    1989-01-01

    Distribution profiles of trace elements in land plants were studied by neutron activation analysis and radioactivity measurements without activation. Number of botanical samples analyzed were more than three thousand in which more than three hundred botanical species were included. New accumulator plants of Co, Cr, Zn, Cd, rare earth elements, Ac, U, etc., were found. Capabilities of accumulating trace elements can be related to the botanical taxonomy. Discussions are given from view points of inorganic chemistry as well as from botanical physiology

  6. Maryland Power Plant Siting Project: an application of the ORNL-Land Use Screening Procedure

    Dobson, J.E.

    1975-01-01

    Since 1974 the Resource Analysis Group in the Regional and Urban Studies Section of the Oak Ridge National Laboratory (ORNL) has been engaged in developing a procedure for regional and local siting analysis known as the ORNL Land Use Screening Procedure (LUSP). This document is the final report of the Maryland Power Plant Siting Project (MPPSP) in which the ORNL LUSP was used to identify candidate areas for power plant sites in northern Maryland. Numerous candidate areas are identified on the basis of four different siting objectives: the minimization of adverse ecologic impact, the minimization of adverse socioeconomic impact, the minimization of construction and operating costs, and a composite of all siting objectives. Siting criteria have been defined for each of these objectives through group processing techniques administered to four different groups of siting specialists. The siting priorities and opinions of each group have been expressed quantitatively and applied to a geographic information system containing 52 variables for each 91.8-acre cell in the northern eight counties of Maryland

  7. Microtubule dynamics of the centrosome-like polar organizers from the basal land plant Marchantia polymorpha.

    Buschmann, Henrik; Holtmannspötter, Michael; Borchers, Agnes; O'Donoghue, Martin-Timothy; Zachgo, Sabine

    2016-02-01

    The liverwort Marchantia employs both modern and ancestral devices during cell division: it forms preprophase bands and in addition it shows centrosome-like polar organizers. We investigated whether polar organizers and preprophase bands cooperate to set up the division plane. To this end, two novel green fluorescent protein-based microtubule markers for dividing cells of Marchantia were developed. Cells of the apical notch formed polar organizers first and subsequently assembled preprophase bands. Polar organizers were formed de novo from multiple mobile microtubule foci localizing to the nuclear envelope. The foci then became concentrated by bipolar aggregation. We determined the comet production rate of polar organizers and show that microtubule plus ends of astral microtubules polymerize faster than those found on cortical microtubules. Importantly, it was observed that conditions increasing polar organizer numbers interfere with preprophase band formation. The data show that polar organizers have much in common with centrosomes, but that they also have specialized features. The results suggest that polar organizers contribute to preprophase band formation and in this way are involved in controlling the division plane. Our analyses of the basal land plant Marchantia shed new light on the evolution of plant cell division. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  8. Exploring the geochemical distribution of organic carbon in early land plants: a novel approach.

    Abbott, Geoffrey D; Fletcher, Ian W; Tardio, Sabrina; Hack, Ethan

    2018-02-05

    Terrestrialization depended on the evolution of biosynthetic pathways for biopolymers including lignin, cutin and suberin, which were concentrated in specific tissues, layers or organs such as the xylem, cuticle and roots on the submillimetre scale. However, it is often difficult, or even impossible especially for individual cells, to resolve the biomolecular composition of the different components of fossil plants on such a scale using the well-established coupled techniques of gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry. Here, we report the application of techniques for surface analysis to investigate the composition of Rhynia gwynne-vaughanii X-ray photoelectron spectroscopy of two different spots (both 300 µm × 600 µm) confirmed the presence of carbon. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) revealed 'chemical maps' (imaging mode with 300 nm resolution) of aliphatic and aromatic carbon in the intact fossil that correlate with the vascular structures observed in high-resolution optical images. This study shows that imaging ToF-SIMS has value for determining the location of the molecular components of fossil embryophytes while retaining structural information that will help elucidate how terrestrialization shaped the early evolution of land plant cell wall biochemistry.This article is part of a discussion meeting issue 'The Rhynie cherts: our earliest terrestrial ecosystem revisited'. © 2017 The Author(s).

  9. Maryland Power Plant Siting Project: an application of the ORNL-Land Use Screening Procedure

    Dobson, J.E.

    1975-01-01

    Since 1974 the Resource Analysis Group in the Regional and Urban Studies Section of the Oak Ridge National Laboratory (ORNL) has been engaged in developing a procedure for regional and local siting analysis known as the ORNL Land Use Screening Procedure (LUSP). This document is the final report of the Maryland Power Plant Siting Project (MPPSP) in which the ORNL LUSP was used to identify candidate areas for power plant sites in northern Maryland. Numerous candidate areas are identified on the basis of four different siting objectives: the minimization of adverse ecologic impact, the minimization of adverse socioeconomic impact, the minimization of construction and operating costs, and a composite of all siting objectives. Siting criteria have been defined for each of these objectives through group processing techniques administered to four different groups of siting specialists. The siting priorities and opinions of each group have been expressed quantitatively and applied to a geographic information system containing 52 variables for each 91.8-acre cell in the northern eight counties of Maryland.

  10. The genetic origins of biosynthesis and light-responsive control of the chemical UV screen of land plants

    Jorgensen, R.

    1994-01-01

    Most land plants possess the capacity to protect themselves from UV light, and do so by producing pigments that absorb efficiently in the UV-A and UV-B regions of the spectrum while allowing transmission of nearly all photosynthetically useful wavelengths. These UV-absorbing pigments are mainly phenylpropanoids and flavonoids. This chapter summarizes current understanding of the mechanism of UV protection in higher land plants, evaluates the information available from lower land plants and their green-algal relatives, and then considers the possible evolutionary origins of this use of chemical filters for selectively screening UV light from solar radiation. It is proposed that photo control over the biosynthesis of UV-absorbing phenylpropanoids and flavonoids may have evolved in concert with the evolution of the high biosynthetic activity necessary for UV protection. The toxicity of phenylpropanoids and flavonoids has been postulated to have been a barrier to the evolution of an effective chemical UV screen, and that some means for sequestering these compounds and/or for controlling their synthesis probably evolved prior to, or in concert with, the evolution of high rates of biosynthesis. The original photoreceptor and signal transduction system is speculated to have been based on photo isomerization of a phenylpropanoid ester and a pre-existing product feedback mechanism for controlling phenylpropanoid biosynthesis. Understanding the original mechanism for photo control of the chemical UV screen of land plants could be valuable for understanding the adaptability of extant land plants to rising levels of solar UV-B radiation and may suggest genetic strategies for engineering improved UV tolerance in crop plants. (author)

  11. Plant indicator values as a tool for land mollusc autecology assessment

    Horsák, Michal; Hájek, Michal; Tichý, Lubomír; Juřičková, Lucie

    2007-09-01

    The aim of this paper was to utilize Ellenberg's plant indicator system for assessing mollusc autecology and to highlight possibilities and advantages of that approach in the case of fen mollusc communities. Molluscs and plants from 137 fen sites in the Western Carpathian Mountains were recorded quantitatively from homogeneous areas of 16 m 2. Water conductivity and pH were measured in the field. Values of Ellenberg's "light, temperature, continentality, moisture, soil reaction, and nutrients" were estimated for each site. The whole data set was processed using ordinations (PCA, DCA, and CCA) and generalized additive models (GAMs). We observed a strong correlation between water pH and Ellenberg soil reaction estimated by plant indicator values ( r = 0.72, P < 0.001). Ellenberg soil reaction was found to be the best predictor of mollusc species composition, which expressed the main mineral-richness gradient. We found the existence of a second important gradient, the gradient of "light", expressing site and canopy openness. A tight correspondence between the results of species response curve modelling based on water conductivity and Ellenberg soil reaction confirmed that "soil reaction" does not express merely pH, but rather the total amount of calcium. We conclude that the Ellenberg's indicator system can be used to study the ecology of land molluscs, an important group of invertebrates in bioindication and nature conservation. Our data and approach could help design appropriate conservation management regimes for threatened snail species. We propose that our approach will be useful also in ecological studies of other animal groups.

  12. The Multifunctional Environmental Energy Tower: Carbon Footprint and Land Use Analysis of an Integrated Renewable Energy Plant

    Emanuele Bonamente

    2015-10-01

    Full Text Available The Multifunctional Environmental Energy Tower (MEET is a single, vertical, stand-alone renewable energy plant designed to decrease the primary energy consumption from fossil fuels, to reduce greenhouse gas emissions, to maximize the energy production from renewable sources available in place and to minimize land use. A feasibility case study was performed for the city of Rome, Italy. Several technologies are exploited and integrated in a single system, including a photovoltaic plant, a geothermal plant and a biomass digester for urban organic waste and sewage sludge. In the proposed configuration, the MEET could cover more than 11% of the electric power demand and up to 3% of the space heating demand of the surrounding urban area. An LCA analysis evaluates the environmental impact in a cradle-to-grave approach for two impact categories: global warming (carbon footprint and land use (land occupation and land transformation. The functional unit is a mix of electric (49.1% and thermal (50.9% energy (kWhmix. The carbon footprint is 48.70 g CO2eq/kWhmix; the land transformation is 4.058 m2/GWhmix; and the land occupation is 969.3 m2y/GWhmix. With respect to other energy production technologies, the carbon footprint is lower and similar to the best-performing ones (e.g., co-generation from wood chips; both of the land use indicators are considerably smaller than the least-impacting technologies. A systematic study was finally performed, and possible optimizations of the original design are proposed. Thanks to the modular design, the conceptual idea can be easily applied to other urban and non-urban scenarios.

  13. Vulnerability of oak-dominated forests in West Virginia to invasive exotic plants: temporal and spatial patterns of nine exotic species using herbarium records and land classification data

    Cynthia D. Huebner

    2003-01-01

    Are oak-dominated forests immune to invasive exotic plants? Herbarium and land classification data were used to evaluate the extent of spread of nine invasive exotic plants and to relate their distributions to remotely-sensed land use types in West Virginia. Collector-defined habitats indicated that the most common habitat was roadsides, but seven of the nine species...

  14. Occurrence and identification of the etiologic agents of plant diseases in cactus (Opuntia ficus-indica Mill. in the semi-arid region of Paraiba

    Anne Evelyne Franco de Souza

    2010-01-01

    Full Text Available Cactus forage (Opuntia ficus-indica Mill., intensely cultivated in dry regions of northeast Brazil, although well adapted to the harsh semi-arid climate is affected by major problems such as pests and diseases, responsible for significant losses in production. This study aimed to investigate the occurrence and diversity of the etiologic agents of diseases of cactus cultivated in 38 municipalities in the semi-arid region of Paraiba. The analyses were conducted and processed at the Laboratory of Phytopathology of the Centro de Ciências Agrárias da Universidade Federal da Paraíba, in Areia - PB. Starting from sick cladodes isolations, multiplications and identifications of the found microorganisms were made. The identification of the microorganisms was achieved through observations of the macro and micromorphological characteristics of the cultures and tests of Gram and pathogenicity. Great incidence and diversity of microorganisms was verified in the cacti researched, but the highest occurrence was mainly that of fungus. The fungi of widest occurrence were: Scytallidium lignicola, Alternate tenuis, Macrophomina phaseolina, Cladosporium cladosporides, Lasiodiplodia theobromae, Fusarium oxysporum f. sp. opuntiarum, Curvularia lunata, Aspergillus niger, Nigrospora sphaerica, Colletotrichum gloeosporioides, Exserohilum turcicum, Pestalotia pitospora, Rhizopus stolonifer, Rhizoctonia solani and Sphaceloma protearum. A bacterium was also detected that was suspected to belong to the Erwinia sp. strain. Satisfaction of the Postulates of Koch proved the infectious nature of the detected microorganisms. High occurrence of the fungus S. lignicola, an agent of scale rot disease in 100% of the places researched, was observed. This fact is of great concern, since the progression of the disease can cause significant losses in production.

  15. Carbon cost of plant nitrogen acquisition: global carbon cycle impact from an improved plant nitrogen cycle in the Community Land Model.

    Shi, Mingjie; Fisher, Joshua B; Brzostek, Edward R; Phillips, Richard P

    2016-03-01

    Plants typically expend a significant portion of their available carbon (C) on nutrient acquisition - C that could otherwise support growth. However, given that most global terrestrial biosphere models (TBMs) do not include the C cost of nutrient acquisition, these models fail to represent current and future constraints to the land C sink. Here, we integrated a plant productivity-optimized nutrient acquisition model - the Fixation and Uptake of Nitrogen Model - into one of the most widely used TBMs, the Community Land Model. Global plant nitrogen (N) uptake is dynamically simulated in the coupled model based on the C costs of N acquisition from mycorrhizal roots, nonmycorrhizal roots, N-fixing microbes, and retranslocation (from senescing leaves). We find that at the global scale, plants spend 2.4 Pg C yr(-1) to acquire 1.0 Pg N yr(-1) , and that the C cost of N acquisition leads to a downregulation of global net primary production (NPP) by 13%. Mycorrhizal uptake represented the dominant pathway by which N is acquired, accounting for ~66% of the N uptake by plants. Notably, roots associating with arbuscular mycorrhizal (AM) fungi - generally considered for their role in phosphorus (P) acquisition - are estimated to be the primary source of global plant N uptake owing to the dominance of AM-associated plants in mid- and low-latitude biomes. Overall, our coupled model improves the representations of NPP downregulation globally and generates spatially explicit patterns of belowground C allocation, soil N uptake, and N retranslocation at the global scale. Such model improvements are critical for predicting how plant responses to altered N availability (owing to N deposition, rising atmospheric CO2 , and warming temperatures) may impact the land C sink. © 2015 John Wiley & Sons Ltd.

  16. Pathways to Resilience in Semi-Arid Economies | CRDI - Centre de ...

    Pathways to Resilience in Semi-Arid Economies. How can populations become resilient to climate change while pursuing economic growth? This question is at the heart of a research project designed to support climate-resilient economic development in semi-arid lands. It will do so by addressing the conditions for ...

  17. CHARACTERISTICS OF ARIDITY CONDITIONS IN SOUTH DOBRUDJA

    A. TISCOVSCHI

    2013-04-01

    Full Text Available Characteristics of Aridity Conditions in South Dobrudja. For most people, the arid and semi-arid lands are those where precipitation is low (less than 200 mm per year, and yet enough for supplying streams capable of temporarily carrying the debris resulted from weathering, but insufficient for encouraging the development of a vegetal cover meant to protect the soil blanket against eroding agents. The drought is a major and permanent climatic risk for the Dobrudja territory as a whole and for South Dobrudja in particular, a territory where hydrographic network is underdeveloped, streams are ephemeral, and semi-endorheic areas are well developed. When the period of moisture deficiency lasts longer, it can bring about a significant water imbalance, which results in crop losses or restrictions in water consumption, thus leading to a number of economic problems. Under the circumstances, the risk of aridity expansion is significant, this being the reason why a better water management system in Romania is urgently needed. In the last decades, the numerous specialty studies undertaken in the area have emphasized an intensification of the process of dryness, because atmospheric and pedological droughts have become more and more serious. Romania is a member of the United Nations Convention to Combat Desertification (UNCCD and the World Meteorological Organization (WMO. It actively participates within the drought management network and the Drought Management Center for Southeastern Europe, which comprises 11 countries. The scope is to work together and exchange experience with the neighboring countries that have recorded positive results and acquired a rich experience in terms of drought management. The employment of appropriate pluvial indices in identifying the areas prone to aridity may prove to be convenient tool for finding practical solutions meant to mitigate the impact of this phenomenon on the local communities living in South Dobrudja.

  18. Aridity under conditions of increased CO2

    Greve, Peter; Roderick, Micheal L.; Seneviratne, Sonia I.

    2016-04-01

    A string of recent of studies led to the wide-held assumption that aridity will increase under conditions of increasing atmospheric CO2 concentrations and associated global warming. Such results generally build upon analyses of changes in the 'aridity index' (the ratio of potential evaporation to precipitation) and can be described as a direct thermodynamic effect on atmospheric water demand due to increasing temperatures. However, there is widespread evidence that contradicts the 'warmer is more arid' interpretation, leading to the 'global aridity paradox' (Roderick et al. 2015, WRR). Here we provide a comprehensive assessment of modeled changes in a broad set of dryness metrics (primarily based on a range of measures of water availability) over a large range of realistic atmospheric CO2 concentrations. We use an ensemble of simulations from of state-of-the-art climate models to analyse both equilibrium climate experiments and transient historical simulations and future projections. Our results show that dryness is, under conditions of increasing atmospheric CO2 concentrations and related global warming, generally decreasing at global scales. At regional scales we do, however, identify areas that undergo changes towards drier conditions, located primarily in subtropical climate regions and the Amazon Basin. Nonetheless, the majority of regions, especially in tropical and mid- to northern high latitudes areas, display wetting conditions in a warming world. Our results contradict previous findings and highlight the need to comprehensively assess all aspects of changes in hydroclimatological conditions at the land surface. Roderick, M. L., P. Greve, and G. D. Farquhar (2015), On the assessment of aridity with changes in atmospheric CO2, Water Resour. Res., 51, 5450-5463

  19. Managing soil moisture on waste burial sites in arid regions

    Anderson, J.E.; Ratzlaff, T.D.; Nowak, R.S.; Markham, O.D.

    1993-01-01

    In semiarid regions, where potential evapotranspiration greatly exceeds precipitation, it is theoretically possible to preclude water form reaching interred wastes by (i) providing a sufficient cap of soil to store precipitation that falls while plants are dormant and (ii) establishing sufficient plant cover to deplete soil moisture during the growing season, thereby emptying the water storage reservoir of the soil. Here the authors discuss the theory and rationale for such an approach and then present the results of a field study to test its efficacy at the Idaho National Engineering Laboratory (INEL). They examined the capacity of four species of perennial plants to deplete soil moisture on simulated waste trenches and determined the effective water storage capacity of the soil. Those data enabled them to estimate the minimum depth of fill soil required to prevent deep drainage. Any of the species studied can use all of the plant-available soil water, even during a very wet growing season. The water storage capacity of the soil studied is 17% by volume, so a trench cap of 1.6 m of soil should be adequate to store precipitation received at the INEL while plants are dormant. They recommend a fill soil depth of 2 m to provide a margin of safety in case water accumulates in local areas as a result of heavy snow accumulation, subsidence, or runoff. Fill soil requirements and choice of plant species will vary, but the concepts and general approach are applicable to other shallow land burial sites in arid or semiarid regions. 23 refs., 5 figs

  20. Quality Assurance Project Plan for Closure of the Central Facilities Area Sewage Treatment Plant Lagoon 3 and Land Application Area

    Lewis, Michael G.

    2016-01-01

    This quality assurance project plan describes the technical requirements and quality assurance activities of the environmental data collection/analyses operations to close Central Facilities Area Sewage treatment Plant Lagoon 3 and the land application area. It describes the organization and persons involved, the data quality objectives, the analytical procedures, and the specific quality control measures to be employed. All quality assurance project plan activities are implemented to determine whether the results of the sampling and monitoring performed are of the right type, quantity, and quality to satisfy the requirements for closing Lagoon 3 and the land application area.

  1. Quality Assurance Project Plan for Closure of the Central Facilities Area Sewage Treatment Plant Lagoon 3 and Land Application Area

    Lewis, Michael G. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-10-01

    This quality assurance project plan describes the technical requirements and quality assurance activities of the environmental data collection/analyses operations to close Central Facilities Area Sewage treatment Plant Lagoon 3 and the land application area. It describes the organization and persons involved, the data quality objectives, the analytical procedures, and the specific quality control measures to be employed. All quality assurance project plan activities are implemented to determine whether the results of the sampling and monitoring performed are of the right type, quantity, and quality to satisfy the requirements for closing Lagoon 3 and the land application area.

  2. Restless 5S: the re-arrangement(s) and evolution of the nuclear ribosomal DNA in land plants.

    Wicke, Susann; Costa, Andrea; Muñoz, Jesùs; Quandt, Dietmar

    2011-11-01

    Among eukaryotes two types of nuclear ribosomal DNA (nrDNA) organization have been observed. Either all components, i.e. the small ribosomal subunit, 5.8S, large ribosomal subunit, and 5S occur tandemly arranged or the 5S rDNA forms a separate cluster of its own. Generalizations based on data derived from just a few model organisms have led to a superimposition of structural and evolutionary traits to the entire plant kingdom asserting that plants generally possess separate arrays. This study reveals that plant nrDNA organization into separate arrays is not a distinctive feature, but rather assignable almost solely to seed plants. We show that early diverging land plants and presumably streptophyte algae share a co-localization of all rRNA genes within one repeat unit. This raises the possibility that the state of rDNA gene co-localization had occurred in their common ancestor. Separate rDNA arrays were identified for all basal seed plants and water ferns, implying at least two independent 5S rDNA transposition events during land plant evolution. Screening for 5S derived Cassandra transposable elements which might have played a role during the transposition events, indicated that this retrotransposon is absent in early diverging vascular plants including early fern lineages. Thus, Cassandra can be rejected as a primary mechanism for 5S rDNA transposition in water ferns. However, the evolution of Cassandra and other eukaryotic 5S derived elements might have been a side effect of the 5S rDNA cluster formation. Structural analysis of the intergenic spacers of the ribosomal clusters revealed that transposition events partially affect spacer regions and suggests a slightly different transcription regulation of 5S rDNA in early land plants. 5S rDNA upstream regulatory elements are highly divergent or absent from the LSU-5S spacers of most early divergent land plant lineages. Several putative scenarios and mechanisms involved in the concerted relocation of hundreds of 5S

  3. Bioenergy to save the world. Producing novel energy plants for growth on abandoned land.

    Schröder, Peter; Herzig, Rolf; Bojinov, Bojin; Ruttens, Ann; Nehnevajova, Erika; Stamatiadis, Stamatis; Memon, Abdul; Vassilev, Andon; Caviezel, Mario; Vangronsveld, Jaco

    2008-05-01

    , where energy and raw material prices have drastically increased over the last decade, they necessitate the development and the establishment of alternative concepts. Biotechnology is available to apply fast breeding to promising energy plant species. It is important that our valuable arable land is preserved for agriculture. The opportunity to switch from low-income agriculture to biogas production may convince small farmers to adhere to their business and by that preserve the identity of rural communities. Overall, biogas is a promising alternative for the future, because its resource base is widely available, and single farms or small local cooperatives might start biogas plant operation.

  4. The Mechanism Forming the Cell Surface of Tip-Growing Rooting Cells Is Conserved among Land Plants.

    Honkanen, Suvi; Jones, Victor A S; Morieri, Giulia; Champion, Clement; Hetherington, Alexander J; Kelly, Steve; Proust, Hélène; Saint-Marcoux, Denis; Prescott, Helen; Dolan, Liam

    2016-12-05

    To discover mechanisms that controlled the growth of the rooting system in the earliest land plants, we identified genes that control the development of rhizoids in the liverwort Marchantia polymorpha. 336,000 T-DNA transformed lines were screened for mutants with defects in rhizoid growth, and a de novo genome assembly was generated to identify the mutant genes. We report the identification of 33 genes required for rhizoid growth, of which 6 had not previously been functionally characterized in green plants. We demonstrate that members of the same orthogroup are active in cell wall synthesis, cell wall integrity sensing, and vesicle trafficking during M. polymorpha rhizoid and Arabidopsis thaliana root hair growth. This indicates that the mechanism for constructing the cell surface of tip-growing rooting cells is conserved among land plants and was active in the earliest land plants that existed sometime more than 470 million years ago [1, 2]. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  5. [Interrelations between plant communities and environmental factors of wetlands and surrounding lands in mid- and lower reaches of Tarim River].

    Zhao, Ruifeng; Zhou, Huarong; Qian, Yibing; Zhang, Jianjun

    2006-06-01

    A total of 16 quadrants of wetlands and surrounding lands in the mid- and lower reaches of Tarim River were surveyed, and the data about the characteristics of plant communities and environmental factors were collected and counted. By using PCA (principal component analysis) ordination and regression procedure, the distribution patterns of plant communities and the relationships between the characteristics of plant community structure and environmental factors were analyzed. The results showed that the distribution of the plant communities was closely related to soil moisture, salt, and nutrient contents. The accumulative contribution rate of soil moisture and salt contents in the first principal component accounted for 35.70%, and that of soil nutrient content in the second principal component reached 25.97%. There were 4 types of habitats for the plant community distribution, i. e., fenny--light salt--medium nutrient, moist--medium salt--medium nutrient, mesophytic--medium salt--low nutrient, and medium xerophytic-heavy salt--low nutrient. Along these habitats, swamp vegetation, meadow vegetation, riparian sparse forest, halophytic desert, and salinized shrub were distributed. In the wetlands and surrounding lands of mid- and lower reaches of Tarim River, the ecological dominance of the plant communities was markedly and unitary-linearly correlated with the compound gradient of soil moisture and salt contents. The relationships between species diversity, ecological dominance, and compound gradient of soil moisture and salt contents were significantly accorded to binary-linear regression model.

  6. Insights into the evolution and diversification of the AT-hook Motif Nuclear Localized gene family in land plants.

    Zhao, Jianfei; Favero, David S; Qiu, Jiwen; Roalson, Eric H; Neff, Michael M

    2014-10-14

    Members of the ancient land-plant-specific transcription factor AT-Hook Motif Nuclear Localized (AHL) gene family regulate various biological processes. However, the relationships among the AHL genes, as well as their evolutionary history, still remain unexplored. We analyzed over 500 AHL genes from 19 land plant species, ranging from the early diverging Physcomitrella patens and Selaginella to a variety of monocot and dicot flowering plants. We classified the AHL proteins into three types (Type-I/-II/-III) based on the number and composition of their functional domains, the AT-hook motif(s) and PPC domain. We further inferred their phylogenies via Bayesian inference analysis and predicted gene gain/loss events throughout their diversification. Our analyses suggested that the AHL gene family emerged in embryophytes and further evolved into two distinct clades, with Type-I AHLs forming one clade (Clade-A), and the other two types together diversifying in another (Clade-B). The two AHL clades likely diverged before the separation of Physcomitrella patens from the vascular plant lineage. In angiosperms, Clade-A AHLs expanded into 5 subfamilies; while, the ones in Clade-B expanded into 4 subfamilies. Examination of their expression patterns suggests that the AHLs within each clade share similar expression patterns with each other; however, AHLs in one monophyletic clade exhibit distinct expression patterns from the ones in the other clade. Over-expression of a Glycine max AHL PPC domain in Arabidopsis thaliana recapitulates the phenotype observed when over-expressing its Arabidopsis thaliana counterpart. This result suggests that the AHL genes from different land plant species may share conserved functions in regulating plant growth and development. Our study further suggests that such functional conservation may be due to conserved physical interactions among the PPC domains of AHL proteins. Our analyses reveal a possible evolutionary scenario for the AHL gene family

  7. Immunomodulatory activity of extracts from Cordia superba Cham. and Cordia rufescens A. DC. (Boraginaceae, plant species native from Brazilian Semi-arid

    José Fernando Oliveira Costa

    Full Text Available The family Boraginaceae is widely distributed in Brazil and in the Northeastern region some species are popularly used to treat symptoms of rheumatism, painful menstruation and dyspepsia. In this work we studied Cordia superba Cham. and C. rufescens A. DC., native from Brazilian Semi-arid region, in order to investigate their immunomodulatory activity. Six extracts were prepared from aerial parts of C. superba and C. rufescens. The cytotoxicity was evaluated using splenocytes from BALB/c mice. The immunomodulatory activity was determined by in vitro assays using activated mouse macrophages and lymphocytes. Peritoneal macrophages obtained from BALB/c mice were stimulated with IFN-gamma and LPS in the presence/absence of the samples. The NO production was measured indirectly through Griess method. Three samples inhibited the production of nitric oxide in values near 50% at a concentration of 100 µg/mL. To evaluate the effects of the extracts on lymphocytes, splenocytes from BALB/c mice were incubated with the samples and concanavalin A. Proliferation inhibition was determined by analysis of ³H-thymidine uptake. Samples from the two species had a strong inhibitory activity on lymphocyte proliferation and IL-2 production. Two chloroform extracts prepared from aerial parts of C. rufescens had the lowest IC50 values (7.6 and 11.0 µg/mL.

  8. Measurement of Vapor Flow As an Important Source of Water in Dry Land Eco-Hydrology

    Wang, Z.; He, Z.; Wang, Y.; Gao, Z.; Hishida, K.

    2014-12-01

    When the temperature of land surface is lower than that of air and deeper soils, water vapor gathers toward the ground surface where dew maybe formed depending on the prevailing dew point and wind speed. Some plants are able to absorb the dew and vapor flow while the soil can readily absorb both. Certain animals such as desert beetles and ants harvest the dew or fog for daily survival. Recently, it is also realized that the dew and vapor flow can be a life-saving amount of water for plant survival at the driest seasons of the year in arid and semi-arid regions. Researches are conducted to quantify the amount of near-surface vapor flow in arid and semi-arid regions in China and USA. Quantitative leaf water absorption and desorption functions were derived based on laboratory experiments. Results show that plant leaves absorb and release water at different speeds depending on species and varieties. The "ideal" native plants in the dry climates can quickly absorb water and slowly release it. This water-holding capacity of plant is characterized by the absorption and desorption functions derived for plant physiology and water balance studies. Field studies are conducted to measure the dynamic vapor flow movements from the atmosphere and the groundwater table to soil surface. Results show that dew is usually formed on soil and plant surfaces during the daily hours when the temperature gradients are inverted toward the soil surface. The amount of dew harvested using gravels on the soil surface was enough to support water melon agriculture on deserts. The vapor flow can be effectively intercepted by artificially seeded plants in semi-arid regions forming new forests. New studies are attempted to quantify the role of vapor flow for the survival of giant sequoias in the southern Sierra Nevada Mountains of California.

  9. Land resources: Forest and arid lands [Chapter 3

    M. G. Ryan; S. R. Archer; R. A. Birdsey; C. N. Dahm; L. S. Heath; J. A. Hicke; D. Y. Hollinger; T. E. Huxman; G. S. Okin; R. Oren; J. T. Randerson; W. H. Schlesinger

    2008-01-01

    This synthesis and assessment report builds on an extensive scientific literature and series of recent assessments of the historical and potential impacts of climate change and climate variability on managed and unmanaged ecosystems and their constituent biota and processes. It identifies changes in resource conditions that are now being observed and examines whether...

  10. Determining termite diversity in arid Namibian rangelands – a ...

    Three methods of sampling termite diversity in arid rangelands were tested in Namibia during the wet (March) and dry (October) seasons of 1998. Six sites were chosen: one pair on each of three farms representing a gradient of land use intensity. At each site, two adjacent plots of 1 ha each were sampled: one plot by a ...

  11. Simulation of water use and herbage growth in arid regions

    Keulen, van H.

    1975-01-01

    The and and semi-arid regions of the world, totalling about 30% of the land surface of the earth, are predominantly used for extensive grazing, as low and erratic rainfall presents too high a risk for arable farming. The population that can be sustained by the animal products -meat, milk or

  12. Trace elements in land plants: concentration ranges and accumulators of rare earths, Ba, Ra, Mn, Fe, Co, and heavy halogens

    Koyama, Mutsuo; Shirakawa, Masahiro; Takada, Jitsuya; Katayama, Yukio; Matsubara, Takashi

    1986-01-01

    More than 2000 samples of land plant leaves, mostly of tree, have been analysed by neutron activation analysis in order to find out macroscopic relations between distributions of chemical elements in plants and soil characteristics. The distributions of the elements in plants were also examined from the view point of botanical taxonomy or phylogeny. New species which accumulate Co, rare earths, Ba, Ra, heavy halogens and other elements have been found. Capability or potentiality for accumulating elements could be related to primarily to species. In several cases, however, it is related to higher ranks of taxonomy, that is, genus or family. The nature of soil is also found to have profound effects on the extent of accumulation of elements in plants. (author)

  13. Gross and net land cover changes in the main plant functional types derived from the annual ESA CCI land cover maps (1992-2015)

    Li, Wei; MacBean, Natasha; Ciais, Philippe; Defourny, Pierre; Lamarche, Céline; Bontemps, Sophie; Houghton, Richard A.; Peng, Shushi

    2018-01-01

    Land-use and land-cover change (LULCC) impacts local energy and water balance and contributes on global scale to a net carbon emission to the atmosphere. The newly released annual ESA CCI (climate change initiative) land cover maps provide continuous land cover changes at 300 m resolution from 1992 to 2015, and can be used in land surface models (LSMs) to simulate LULCC effects on carbon stocks and on surface energy budgets. Here we investigate the absolute areas and gross and net changes in different plant functional types (PFTs) derived from ESA CCI products. The results are compared with other datasets. Global areas of forest, cropland and grassland PFTs from ESA are 30.4, 19.3 and 35.7 million km2 in the year 2000. The global forest area is lower than that from LUH2v2h (Hurtt et al., 2011), Hansen et al. (2013) or Houghton and Nassikas (2017) while cropland area is higher than LUH2v2h (Hurtt et al., 2011), in which cropland area is from HYDE 3.2 (Klein Goldewijk et al., 2016). Gross forest loss and gain during 1992-2015 are 1.5 and 0.9 million km2 respectively, resulting in a net forest loss of 0.6 million km2, mainly occurring in South and Central America. The magnitudes of gross changes in forest, cropland and grassland PFTs in the ESA CCI are smaller than those in other datasets. The magnitude of global net cropland gain for the whole period is consistent with HYDE 3.2 (Klein Goldewijk et al., 2016), but most of the increases happened before 2004 in ESA and after 2007 in HYDE 3.2. Brazil, Bolivia and Indonesia are the countries with the largest net forest loss from 1992 to 2015, and the decreased areas are generally consistent with those from Hansen et al. (2013) based on Landsat 30 m resolution images. Despite discrepancies compared to other datasets, and uncertainties in converting into PFTs, the new ESA CCI products provide the first detailed long-term time series of land-cover change and can be implemented in LSMs to characterize recent carbon dynamics

  14. Soil and plant responses from land application of saline-sodic waters: Implications of management

    Vance, G.F.; King, L.A.; Ganjegunte, G.K. [University of Wyoming, Laramie, WY (United States). Department for Renewable Resources

    2008-09-15

    Land application of co-produced waters from coalbed natural gas (CBNG) wells is one management option used in the Powder River Basin (PRB) of Wyoming and Montana. Unfortunately the co-produced CBNG waters may be saline and/or sodic. The objective of this study was to examine the effects of irrigation with CBNG waters on soils and plants in the PRB. Soil properties and vegetation responses resulting from 1 to 4 yr of saline sodic water (electrical conductivity (EC) 1.6-4.8 dS m{sup -1} sodium adsorption ratio (SAR), 17-57 mmol L- applications were studied during 2003 and 2004 field seasons on sites (Ustic Torriorthent Haplocambid, Haplargid and Paleargid) representing native range grasslands seeded grass hayfields and alfalfa hayfields. Parameters measured from each irrigated site were compared directly with representative non-irrigated sites. Soil chemical and physical parameters including pH, EC, SAR, exchangeable sodium percent, texture, bulk density, infiltration and Darcy flux rates, were measured at various depth intervals to 120 cm. Mulitple-year applications of saline sodic water produced consistent trends of increased soil EC AND SAR values to depths of 30 cm reduced surface infiltration rates and lowered Darcy flux rates to 120 cm. Significant differences (p {le} 0.05) were determined between irrigated and non-irrigated areas for EC, SAR infiltration rates and Darcy flux (p {le} 0.10) at most sites. Saline sodic CBNG water applications significantly increased native perennial grass biomass production and cover on irrigated as compared with non-irrigated sites; however overall species evenness decreased. Biological effects were variable and complex reflecting site-specific conditions and water and soil management strategies.

  15. Diversity and activity of denitrifiers of Chilean arid soil ecosystems

    Julieta eOrlando

    2012-04-01

    Full Text Available The Chilean sclerophyllous matorral is a Mediterranean semiarid ecosystem affected by erosion, with low soil fertility and limited by nitrogen. However, limitation of resources is even more severe for desert soils such as from the Atacama Desert, one of the most extreme arid deserts on Earth. Topsoil organic matter, nitrogen and moisture content were significantly higher in the semiarid soil compared to the desert soil. Although the most significant loss of biologically preferred nitrogen from terrestrial ecosystems occurs via denitrification, virtually nothing is known on the activity and composition of denitrifier communities thriving in arid soils. In this study, we explored denitrifier communities from two soils with profoundly distinct edaphic factors. While denitrification activity in the desert soil was below detection limit, the semiarid soil sustained denitrification activity. To elucidate the genetic potential of the soils to sustain denitrification processes we performed community analysis of denitrifiers based on nitrite reductase (nirK and nirS genes as functional marker genes for this physiological group. Presence of nirK-type denitrifiers in both soils was demonstrated but failure to amplify nirS from the desert soil suggests very low abundance of nirS-type denitrifiers shedding light on the lack of denitrification activity. Phylogenetic analysis showed a very low diversity of nirK with only three distinct genotypes in the desert soil which conditions presumably exert a high selection pressure. While nirK diversity was also limited to only few, albeit distinct genotypes, the semiarid matorral soil showed a surprisingly broad genetic variability of the nirS gene. The Chilean matorral is a shrub land plant community which form vegetational patches stabilizing the soil and increasing its nitrogen and carbon content. These islands of fertility may sustain the development and activity of the overall microbial community and of

  16. Diversity and activity of denitrifiers of chilean arid soil ecosystems.

    Orlando, Julieta; Carú, Margarita; Pommerenke, Bianca; Braker, Gesche

    2012-01-01

    The Chilean sclerophyllous matorral is a Mediterranean semiarid ecosystem affected by erosion, with low soil fertility, and limited by nitrogen. However, limitation of resources is even more severe for desert soils such as from the Atacama Desert, one of the most extreme arid deserts on Earth. Topsoil organic matter, nitrogen and moisture content were significantly higher in the semiarid soil compared to the desert soil. Although the most significant loss of biologically preferred nitrogen from terrestrial ecosystems occurs via denitrification, virtually nothing is known on the activity and composition of denitrifier communities thriving in arid soils. In this study we explored denitrifier communities from two soils with profoundly distinct edaphic factors. While denitrification activity in the desert soil was below detection limit, the semiarid soil sustained denitrification activity. To elucidate the genetic potential of the soils to sustain denitrification processes we performed community analysis of denitrifiers based on nitrite reductase (nirK and nirS) genes as functional marker genes for this physiological group. Presence of nirK-type denitrifiers in both soils was demonstrated but failure to amplify nirS from the desert soil suggests very low abundance of nirS-type denitrifiers shedding light on the lack of denitrification activity. Phylogenetic analysis showed a very low diversity of nirK with only three distinct genotypes in the desert soil which conditions presumably exert a high selection pressure. While nirK diversity was also limited to only few, albeit distinct genotypes, the semiarid matorral soil showed a surprisingly broad genetic variability of the nirS gene. The Chilean matorral is a shrub land plant community which form vegetational patches stabilizing the soil and increasing its nitrogen and carbon content. These islands of fertility may sustain the development and activity of the overall microbial community and of denitrifiers in particular.

  17. Land-use change has no detectable effect on reproduction of a disturbance-adapted, hawkmoth-pollinated plant species.

    Skogen, Krissa A; Jogesh, Tania; Hilpman, Evan T; Todd, Sadie L; Rhodes, Matthew K; Still, Shannon M; Fant, Jeremie B

    2016-11-01

    Land-use change is cited as a primary driver of global biodiversity loss, with myriad consequences for species, populations, and ecosystems. However, few studies have examined its impact on species interactions, particularly pollination. Furthermore, when the effects of land-use change on pollination have been studied, the focus has largely been on species pollinated by diurnal pollinators, namely, bees and butterflies. Here, we focus on Oenothera harringtonii, a night-flowering, disturbance-adapted species that has experienced a range-wide gradient of land-use change. We tested the hypothesis that the negative impacts of land-use change are mitigated by long-distance pollination. Our study included both temporal (4 yr) and spatial (19 populations range-wide, and 1, 2, and 5 km from the population center) data, providing a comprehensive understanding of the role of land-use change on pollination biology and reproduction. We first confirmed that O. harringtonii is self-incompatible and reliant on pollinators for reproduction. We then showed that hawkmoths (primarily Hyles lineata) are highly reliable and effective pollinators in both space and time. Unlike other studies, we did not detect an effect of population size, increased isolation, or a reduction in suitable habitat in areas with evidence of land-use change on pollination (visitation, pollen removal and deposition). Furthermore, the proportion of suitable habitat and other fragmentation metrics examined were not associated with population size or density in this plant species. We conclude that nocturnal pollination of Oenothera harringtonii via hawkmoths is robust to the negative impacts of land-use change. © 2016 Skogen et al. Published by the Botanical Society of America. This work is licensed under a Creative Commons Attribution License (CC-BY).

  18. HISTORY OF LAND RESOURCES MANAGEMENT AND THE PLANT WORLD: WHAT WE TAKE THE FUTURE?

    Lidia Borisovna Kuzina

    2018-03-01

    Full Text Available The evolution of management of land resources and flora in connection with the history of Russian statehood, legislative acts is considered. The specifics of legislation on land and nature are described. The structure of top-level management in the post-Soviet period in the Russian Federation and in the world community is described.

  19. RECYCLING OF WATER TREATMENT PLANT SLUDGE VIA LAND APPLICATION: ASSESSMENT OF RISK

    Water treatment sludges (WTS) offer potential benefits when applied to soil and recycling of the waste stream via land application has been proposed as a management option. Recycling of WTS to the land helps conserve landfill disposal capacity and natural resources, but potential...

  20. [Edge effect of the plant community structure on land-bridge islands in the Thousand Island Lake].

    Su, Xiao-Fei; Yuan, Jin-Feng; Hu, Guang; Xu, Gao-Fu; Yu, Ming-Jian

    2014-01-01

    The research was conducted on 29 land-bridge islands in the Thousand Island Lake (TIL), where long-term monitoring plots were set up during 2009-2010. The community attributes including species richness, Shannon index, plant mean height, plant mean diameter at breast height (DBH) and plant density along the edge-interior gradient from edge to interior forest were calculated to investigate the edge effect. The results showed that the species richness and Shannon index were affected through the whole gradient (larger than 50 m), while the range of edge effect was 20-30 m on mean plant height, and 10 m on plant density and mean DBH. Community attributes differed significantly among the edge gradients. The species richness and Shannon index peaked at the intermediate edge gradient. Plant density decreased and plant mean height increased along the edge to interior gradient. All five community attributes were significantly associated with the edge gradient, also different functional groups, evergreen or deciduous species, trees or shrubs, shade tolerant or shade intolerant species, were differentially influenced by the edge effect. It was demonstrated the influence of edge effect on the fragmented forest community varied with community attributes and functional groups.

  1. SPECIES COMPOSITION, DISTRIBUTION, LIFE FORMS AND FOLK NOMENCLATURE OF FOREST AND COMMON LAND PLANTS OF WESTERN CHITWAN, NEPAL

    Dangol, D. R.

    2012-01-01

    This paper enumerates 349 plant species belonging to 77 families of vascular plants collected in the winter seasons of 1996 and 2000 by the flora teams of the Population and Ecology Research Laboratory, Nepal. Of the total species, 249 species belong to dicotyledons, 87 species to monocotyledons and 13 species to pteridophytes. Among the families, dicotyledons contributed the highest number of families (55 in number) followed by monocotyledons and pteridophytes. In the study areas, species composition varies with the type of habitats in the study plots. Some species are unique in distribution. The highest unique species are contributed by common lands (87 spp.), followed by the Chitwan National Park forest (36 spp.) and Tikauli forest (32 spp.). Ageratum houstonianum Mill., Cynodon dactylon (L.) Pers., Imperata cylindrica (L.) Beauv., Rungia parviflora (Retz.) Nees, Saccharum spontaneum L. and Thelypteris auriculata (J. Sm.) K. Iwats are the most common species across all the research blocks. Of the listed plants, many plants have local names either in Nepalese or other tribal languages. Plants are named in different ways on the basis of habit, habitat, smell, taste, and morphological characters of the plants, which are also the basis of nomenclature in plant taxonomy. PMID:22962539

  2. The environmental vegetation index: A tool potentially useful for arid land management. [Texas and Mexico, plant growth stress due to water deficits

    Gray, T. I., Jr.; Mccrary, D. G. (Principal Investigator)

    1981-01-01

    The NOAA-6 AVHRR data sets acquired over South Texas and Mexico during the spring of 1980 and after Hurricane Allen passed inland are analyzed. These data were processed to produce the Gray-McCrary Index (GMI's) for each pixel location over the selected area, which area contained rangeland and cropland, both irrigated and nonirrigated. The variations in the GMI's appear to reflect well the availability of water for vegetation. The GMI area maps are shown to delineate and to aid in defining the duration of drought; suggesting the possibility that time changes over a selected area could be useful for irrigation management.

  3. Rainwater harvesting in arid and semi-arid zones

    Boers, T.M.

    1994-01-01

    In arid and semi-arid regions, the scarcity of water can be alleviated by rainwater harvesting, which is defined as a method of inducing, collecting, storing, and conserving local surface runoff for agriculture. Rainwater harvesting can be applied with different

  4. Soil to plant 137Cs transfer factors in Zea mays and Phaseolus vulgaris in a semi-arid ecosystem from a radioactive waste site

    Cervantes, M.L.; Segovia, N.; Gaso, M.I.; Palacios, J.C.

    2002-01-01

    A study of 137 Cs in soil, maize plants, (Zea mays) and beans (Phaseolus vulgaris) has been performed at the confined Storage Centre for Radioactive Waste from Mexico. Under field conditions the site was divided in four zones with different soil contamination characteristics. The plants were grown 'in situ' reproducing the local agricultural practices without fertilizers, pesticides or artificial irrigation.The 137 Cs determinations were performed using a low background gamma spectrometry system with an HPGe detector. The results indicate that one of the zones had a striking 137 Cs contamination in the soil and the uptake by the grown plants showed the highest specific activities at the root. For the edible parts of the plants the amount of 137 Cs in the maize grains was one order of magnitude lower than for the beans. The transfer factors ranges for the different parts of the maize plants was from 0.001 in the grain to 0.6 in the root. (author)

  5. Changes in Soil Organic Matter Abundance, Molecular Composition, and Diversity in an Arid Ecosystem in Response to Long-term Elevated CO2 Manipulation.

    Hess, N. J.; Tfaily, M.; Evans, R. D.; Koyama, A.

    2017-12-01

    Little is known about how soils in arid ecosystems will respond to rising atmospheric CO2 concentration yet arid and semi-arid ecosystems cover more than 40% of Earth's land surface. Previous work in the Mojave Desert (Evans et al., 2014 Nature Climate Change) reported higher soil organic carbon (SOC) and total nitrogen (N) concentrations following 10 years exposure to elevated atmospheric CO2 at the Nevada Desert Free-Air-Carbon dioxide-Enrichment (FACE) Facility (NDFF). In this study, we investigated potential mechanisms that resulted in increased SOC and total N accumulation and stabilization using high resolution mass spectrometry at the NDFF site. Samples were collected from soil profiles to 1 m in depth with a 0.2 m a increment under the dominant evergreen shrub Larrea tridentata. The differences in the molecular composition and diversity of soil organic matter (SOM) were more evident in surface soils and declined with depth, and were consistent with higher SOC and total N concentrations under elevated than ambient CO2. Our molecular analysis also suggested increased root exudation and/or microbial necromass from stabilization of labile C and N contributed to SOM and N stocks. Increased microbial activity and metabolism under elevated CO2 compared to ambient plots suggested that elevated CO2 altered microbial carbon (C) use patterns, reflecting changes in the quality and quantity of SOC inputs. We found that plant-derived compounds were primary substrates for microbial activity under elevated CO2 and microbial products were the main constituents of stabilized SOM. Our results suggest that arid ecosystems are a potential large C sink under elevated CO2, give the extensive coverage of the land surface, and that labile compounds are transformed to stable SOM via microbial processes. Arid systems are limited by water, and thus may have a different C storage potential under changing climates than other ecosystems that are limited by nitrogen or phosphorus.

  6. Change detection and identification of land potential for planting Krajood (Lepironia articulata in Thale Noi, Southern Thailand

    Jitnapa Maeaid

    2012-07-01

    Full Text Available Lepironia articulata, commonly called grey sedge or krajood, can be transformed into various products to generateextra income for local families in the southern part of Thailand. In recent years, the amount of Lepironia articulata used asraw material has decreased and does not currently meet the demand for the resource. Appropriate areas where naturalresources and the environment can be restored and the abundance of natural produce can be increased must be sought.Therefore, this research considered the opportunity to identify appropriate areas for planting Lepironia articulata. Geographicinformation system (GIS and remote sensing were integrated to map land use changes in 1990, 1998 and 2006 in theThale Noi area. The study found that from 1990-1998, emergent aquatic areas increased by 16.18 square kilometers, the areaof swamp forests increased by 15.33 square kilometers, the area of rice paddies decreased by 0.80 square kilometers, and thearea of mixed orchards increased by approximately 0.32 square kilometers. From 1998-2006, the area of swamp forestsincreased by 1.9 square kilometers, but emergent aquatic areas decreased by 1.23 square kilometers. The area of rubberplantations increased by 0.63 square kilometers, and the area of rice paddies decreased by 0.69 square kilometers. This studyaimed to define land potential for Krajood (Lepironia articulata cultivation in the Thale Noi area by considering five factors:land use, distance from water sources, slope, soil characteristics, and soil drainage. The study found that the areas of highpotential for planting Lepironia articulata were wetlands and near water sources, covering a total area of 5.54 square kilometers.The areas with moderate potential were swamp forests and rice paddies, covering a total area of 4.27 square kilometres.GIS and remote sensing were found to be very useful for identifying land use changes and potential areas for plantingLepironia articulata.

  7. Effectiveness of Some Ameliorants in Reducing Co2 and N2o Emission in Corn Planting in Peat Land

    Eni Maftuah

    2016-04-01

    Full Text Available Amelioration is very important in supporting plant growth in peat land. The use of low emission ameliorant will support the sustainability of agricultural system in peat land. The research is intended to study the effectiveness of some ameliorants in reducing CO2 and N2O emission in corn planting in peat land. The research was conducted in April to October 2013, in Kalampangan Village Palangkaraya Municipality Central Kalimantan. Ameliorant materials used were chicken manure fertilizer, domolite, mineral soil, paddy husk biochar, coconut shell biochar. Ameliorant treatments applied were the type of ameliorant compositions, those were (A1 80% chicken manure fertilizer + 20% dolomite, (A2 20% chicken manure fertilizer + 20% agricultural weeds + 20% spodosol mineral soil + 20% “purun tikus” (eleocharis dulcis compost + 20% dolomite, (A3 19% chicken manure fertilizer + 9% dolomite + 72% mineral soil, (A4 100% coconut shell biochar, (A5 paddy husk biochar, (A6 farmer’s way (20% ash + 40% spodosol mineral soil + 40% chicken manure fertilizer and control. Experiment design used a Randomized Factorial Block Design, with 3 repetitions. Ameliorant dosage used was 7.5 t/ha. The crop used was hybrid corn. Parameters which were observed periodically were emission of CO2 and N2O, ground water level height, soil pH and Eh, once a month for 5 periods. The research result showed that ameliorant was capable of reducing emission of both CO2 and N2O in corn planting in peat land. Coconut shell biochar could reduce emission of CO2 up to 26% as compared with control, whereas paddy husk biochar could reduce emission of N2O up to 52% as compared with control.

  8. Role of Ethanol Plants in Dakotas’ Land Use Change: Analysis Using Remotely Sensed Data

    Arora, Gaurav; Wolter, Peter T.; Feng, Hongli; Hennessy, David A.

    2015-01-01

    North and South Dakota have experienced rapid land-use changes in the past decade. Recent studies have shown that these land-use changes are mainly characterized by conversions of grasslands to crop production, especially corn and soybeans. Approximately 271,000 hectares of grasslands were lost to corn and soy production in 2006-2011 period, almost seven times the losses in 1989-2003. The implications of these changing land-uses range from reduced biodiversity and loss of habitat for waterfow...

  9. Changes in the distribution of alien plants along roadsides in relation to adjacent land use over the course of 40 years

    Dostálek, J.; Frantík, Tomáš; Šilarová, V.

    2016-01-01

    Roč. 150, č. 3 (2016), s. 442-448 ISSN 1126-3504 Institutional support: RVO:67985939 Keywords : adjacent land use * alien plants * roads Subject RIV: EH - Ecology, Behaviour Impact factor: 1.390, year: 2016

  10. Potential of arid zone vegetation as a source of substrates

    Bassham, J.A.

    1977-11-01

    Three aspects of the potential of vegetation in arid zones as a source of substrates are discussed. The first includes the limitations on efficiency of conversion of solar energy to the stored chemical energy of biomass in green plants, and the subsequent biochemical pathways of carbon dioxide fixation and biosynthesis. Second is the potential of plants endogenous to arid zones. Finally, the use of covered agriculture or controlled environmental agriculture (CEA) is considered both in its present form and in terms of possible extenion to the large scale production of stable crops. (JGB)

  11. Effect of the recent land use on the plant diversity and community structure of Omayed Biosphere Reserve, Egypt

    Dalia A. Ahmed

    2015-07-01

    Full Text Available The present study aims at describing and analysing the floristic composition and vegetation types, as well as determining the effect of recent land uses on the vegetation structure. It aims also at identifying the alien plants species and elucidating the impact of these species on the plant diversity and community structure of the study area. One hundred and ninety stands were selected monthly for this study, 145 species were recorded (69 perennials and 76 annuals related to 83 genera, 40 families in 9 identified habitats in El-Omayed Biosphere Reserve (coastal sand dunes, salt marshes, saline depression, non-saline depression, inland ridges, inland plateau, irrigation canals, road sides and cultivated lands. Therophytes were the most represented life form. Three habitat groups resulted after the application of TWINSPAN and DCA as classification and ordination techniques: 2 represented the natural habitats and one represented the urban and cultivated habitats. Group I represented coastal dunes and salt marshes GII: saline depressions, non-saline depressions, inland plateau and inland ridges and GIII: irrigation canals, road sides and cultivated lands. Coastal dunes had the highest species richness (α-diversity, followed by cultivated lands, while inland plateau had the lowest; but saline depressions had the highest species turnover (β-diversity. Non-saline depressions had the highest relative evenness, while saline depressions had the highest relative concentration of dominance. Coastal dunes had highest values of calcium carbonates and calcium ions, and salt marshes had the highest salinity, pH, potassium and sodium contents, but cultivated lands had the highest values of silt, clay and organic matter. The diagram resulting from CCA showed an influence of most soil variables, except nitrogen, calcium and potassium. Twenty two species were recorded for the first time in the study area. The recent land use (overgrazing, wood cutting and

  12. Regulation of Population Densities of Heterodera cajani and Other Plant-Parasitic Nematodes by Crop Rotations on Vertisols, in Semi-Arid Tropical Production Systems in India

    Sharma, S. B.; Rego, T. J.; Mohiuddin, M.; Rao, V. N.

    1996-01-01

    The significance of double crop (intercrop and sequential crop), single crop (rainy season crop fallow from June to September), and rotations on densities of Heterodera cajani, Helicotylenchus retusus, and Rotylenchulus reniformis was studied on Vertisol (Typic Pellusterts) between 1987 and 1993. Cowpea (Vigna sinensis), mungbean (Phaseolus aureus), and pigeonpea (Cajanus cajan) greatly increased the population densities of H. cajani and suppressed the population densities of other plant-parasitic nematodes. Mean population densities of H. cajani were about 8 times lower in single crop systems than in double crop systems, with pigeonpea as a component intercrop. Plots planted to sorghum, safflower, and chickpea in the preceding year contained fewer H. cajani eggs and juveniles than did plots previously planted to pigeonpea, cowpea, or mungbean. Continuous cropping of sorghum in the rainy season and safflower in the post-rainy season markedly reduced the population density of H. cajani. Sorghum, safflower, and chickpea favored increased population densities of H. retusus. Adding cowpea to the system resulted in a significant increase in the densities of R. reniformis. Mean densities of total plant-parasitic nematodes were three times greater in double crop systems, with pigeonpea as a component intercrop than in single crop systems with rainy season fallow component. Cropping systems had a regulatory effect on the nematode populations and could be an effective nematode management tactic. Intercropping of sorghum with H. cajani tolerant pigeonpea could be effective in increasing the productivity of traditional production systems in H. cajani infested regions. PMID:19277141

  13. Potential climatic refugia in semi-arid, temperate mountains: plant and arthropod assemblages associated with rock glaciers, talus slopes, and their forefield wetlands, Sierra Nevada, California, USA

    Constance I. Millar; Robert D. Westfall; Angela Evenden; Jeffrey G. Holmquist; Jutta Schmidt-Gengenbach; Rebecca S. Franklin; Jan Nachlinger; Diane L. Delany

    2015-01-01

    Unique thermal and hydrologic regimes of rock-glacier and periglacial talus environments support little-studied mountain ecosystems. We report the first studies of vascular plant and arthropod diversity for these habitats in the central Sierra Nevada, California, USA. Surfaces of active rock glaciers develop scattered islands of soil that provide habitat for vegetation...

  14. Using LIDAR and Quickbird Data to Model Plant Production and Quantify Uncertainties Associated with Wetland Detection and Land Cover Generalizations

    Cook, Bruce D.; Bolstad, Paul V.; Naesset, Erik; Anderson, Ryan S.; Garrigues, Sebastian; Morisette, Jeffrey T.; Nickeson, Jaime; Davis, Kenneth J.

    2009-01-01

    Spatiotemporal data from satellite remote sensing and surface meteorology networks have made it possible to continuously monitor global plant production, and to identify global trends associated with land cover/use and climate change. Gross primary production (GPP) and net primary production (NPP) are routinely derived from the MOderate Resolution Imaging Spectroradiometer (MODIS) onboard satellites Terra and Aqua, and estimates generally agree with independent measurements at validation sites across the globe. However, the accuracy of GPP and NPP estimates in some regions may be limited by the quality of model input variables and heterogeneity at fine spatial scales. We developed new methods for deriving model inputs (i.e., land cover, leaf area, and photosynthetically active radiation absorbed by plant canopies) from airborne laser altimetry (LiDAR) and Quickbird multispectral data at resolutions ranging from about 30 m to 1 km. In addition, LiDAR-derived biomass was used as a means for computing carbon-use efficiency. Spatial variables were used with temporal data from ground-based monitoring stations to compute a six-year GPP and NPP time series for a 3600 ha study site in the Great Lakes region of North America. Model results compared favorably with independent observations from a 400 m flux tower and a process-based ecosystem model (BIOME-BGC), but only after removing vapor pressure deficit as a constraint on photosynthesis from the MODIS global algorithm. Fine resolution inputs captured more of the spatial variability, but estimates were similar to coarse-resolution data when integrated across the entire vegetation structure, composition, and conversion efficiencies were similar to upland plant communities. Plant productivity estimates were noticeably improved using LiDAR-derived variables, while uncertainties associated with land cover generalizations and wetlands in this largely forested landscape were considered less important.

  15. Influence of soil physical and chemical variables on species composition and richness of plants in the arid region of Tabuk, Saudi Arabia

    Al-Mutairi Khalid Awadh

    2017-06-01

    Full Text Available The present study aims to investigate the effect of soil physical and chemical variables on the species richness and the floristic composition in four sites (Alwaz, Alqan, Sharma and Zetah of Tabuk region in the Northwestern part of Arabian Peninsula. Only organic matter (OM, pH and calcium (Ca showed significant differences (P < 0.05 amongst the four studied sites. Only magnesium and sodium were selected in the forward regression model and showed to be strong drivers of species richness of plants in Tabuk region (Adj-R2 = 0.438, F2,13 = 6.85, P = 0.009. The multivariate analysis of canonical correspondence analysis (CCA was applied to reveal the effect of the physical and chemical variables on the species composition of the plants. The CCA classifies the plant species into three groups based on their preference to the environmental variables. The first group of plant species (Group 1 is characterised by positive preference to the chloride (Cl and negative relationship with OM and pH. The second group (Group 2 is positively correlated with most of the soil variables such as OM, calcium (Ca, potassium (K, bicarbonate (HCO3, electrical conductivity (EC, sulphate (SO4 and sodium (Na. The third group (Group 3 has positive relationship with carbonate (CO3 and negative relationship with EC and magnesium (Mg. The chloride, sodium, sulphate, EC and carbonate are the main environmental factors influencing the plant species composition in Tabuk region. The cluster analysis based on the Euclidian measure shows that Alqan and Zetah have closer species composition compared to Sharma.

  16. Land Use Alters the Plant-Derived Carbon and Nitrogen Pools in Terraced Rice Paddies in a Mountain Village

    Seiji Shimoda

    2017-10-01

    Full Text Available In Japan, terraced paddies in mountain villages are symbolic of the traditional landscape, but they are gradually being abandoned. To compare plant-derived C and N among land uses, we compared adjacent forest floor (FF, agricultural paddy (AP, and post-agricultural paddy (PP sites. Long-term litter accumulation could explain the significantly higher litter C and belowground biomass C in FF than in AP and PP. The low-density-fraction (LF soil C was significantly higher in FF than in PP and better reflected land use than the whole-soil C. The AP soil held more N than FF and PP at 20–30 cm, associated with higher LF soil N. Periodic tillage in AP maintains the LF soil N, but N supplied to the surface soil reduced with depth following abandonment. Differences in recycling of organic matter and nutrients among land uses are crucial to plant-derived C and N contents of soil.

  17. Management, use and ecology of medicinal plants in the degraded dry lands of Tigray, Northern Ethiopia

    Hizikias, E.B.; Aynekulu, E.; Mekuria, W.; Endale, D.

    2011-01-01

    An ethnomedicinal study was conducted to document the indigenous medicinal plant knowledge on the management, use, and ecology of locally important medicinal plants in Tigray, Northern Ethiopia. Ethnobotanical data were collected from 250 people, using semi-structured questionnaires, field

  18. Impact of soil salinity on arbuscular mycorrhizal fungi biodiversity and microflora biomass associated with Tamarix articulata Vahll rhizosphere in arid and semi-arid Algerian areas.

    Bencherif, Karima; Boutekrabt, Ammar; Fontaine, Joël; Laruelle, Fréderic; Dalpè, Yolande; Sahraoui, Anissa Lounès-Hadj

    2015-11-15

    Soil salinization is an increasingly important problem in many parts of the world, particularly under arid and semi-arid areas. Unfortunately, the knowledge about restoration of salt affected ecosystems using mycorrhizae is limited. The current study aims to investigate the impact of salinity on the microbial richness of the halophytic plant Tamarix articulata rhizosphere. Soil samples were collected from natural sites with increasing salinity (1.82-4.95 ds.m(-1)). Six arbuscular mycorrhizal fungi (AMF) species were isolated from the different saline soils and identified as Septoglomus constrictum, Funneliformis mosseae, Funneliformis geosporum, Funneliformis coronatum, Rhizophagus fasciculatus, and Gigaspora gigantea. The number of AMF spores increased with soil salinity. Total root colonization rate decreased from 65 to 16% but remained possible with soil salinity. Microbial biomass in T. articulata rhizosphere was affected by salinity. The phospholipid fatty acids (PLFA) C16:1ω5 as well as i15:0, a15:0, i16:0, i17:0, a17:0, cy17:0, C18:1ω7 and cy19:0 increased in high saline soils suggesting that AMF and bacterial biomasses increased with salinity. In contrast, ergosterol amount was negatively correlated with soil salinity indicating that ectomycorrhizal and saprotrophic fungal biomasses were reduced with salinity. Our findings highlight the adaptation of arbuscular and bacterial communities to natural soil salinity and thus the potential use of mycorrhizal T. articulata trees as an approach to restore moderately saline disturbed arid lands. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Determine the optimum spectral reflectance of juniper and pistachio in arid and semi-arid region

    Fadaei, Hadi; Suzuki, Rikie

    2012-11-01

    Arid and semi-arid areas of northeast Iran cover about 3.4 million ha are populated by two main tree species, the broadleaf Pistacia vera. L (pistachio) and the conifer Juniperus excelsa ssp. polycarpos (Persian juniper). Natural stands of pistachio in Iran are not only environmentally important but genetically essential as seed sources for pistachio production in orchards. In this study, we estimated the optimum spectral reflectance of juniper forests and natural pistachio stands using remote sensing to help in the sustainable management and production of pistachio in Iran. In this research spectral reflectance are able to specify of multispectral from Advanced Land Observing Satellite (ALOS) that provided by JAXA. These data included PRISM is a panchromatic radiometer with a 2.5 m spatial resolution at nadir, has one band with a wavelength of 0.52-0.77 μm and AVNIR-2 is a visible and near infrared radiometer for observing land and coastal zones with a 10 m spatial resolution at nadir, has four multispectral bands: blue (0.42-0.50 μm), green (0.52-0.60 μm), red (0.61-0.69 μm), and near infrared (0.76-0.89 μm). Total ratio vegetation index (TRVI) of optimum spectral reflectance of juniper and pistachio have been evaluated. The result of TRVI for Pistachio and juniper were (R2= 0.71 and 0.55). I hope this research can provide decision of managers to helping sustainable management for arid and semi-arid regions in Iran.

  20. Assessment of Spatio-temporal Barren-lands Expansion and Agricultural Adaptation due to Climate Change and Anthropogenic Activity: A Geospatial Approach in Hot Semi-arid Region of Maharashtra State, India

    Roy, A.; Inamdar, A. B.

    2017-12-01

    Major parts of Upper Godavari River Basin are intensely drought prone and climate vulnerable in Maharashtra State, India. The economy of the state depends on the agronomic productivity of this region. So, it is necessary to monitor and regulate the effects of climate change and anthropogenic activity on agricultural land in that region. This study investigates and maps the barren-lands and alteration of agricultural lands, their decadal deviations with the multi-temporal LANDSAT satellite images; and finally quantifies the agricultural adaptations. This work involves the utilization of remote sensing and GIS tools and modeling. First, climatic trend analysis is carried out with dataset obtained from India Meteorological Department. Then, multi-temporal LANDSAT images are classified (Level I, hybrid classification technique are followed) to determine the decadal Land Use Land Cover (LULC) changes and correlated with the agricultural water demand. Finally, various LANDSAT band analysis is conducted to determine irrigated and non-irrigated cropping area estimation and identifying the agricultural adaptations. The analysis of LANDSAT images shows that barren-lands are most increased class during the study period. The overall spatial extent of barren-lands are increased drastically during the study period. The geospatial study (class-to-class conversion study) shows that, most of the conversion of the barren-lands are from the agricultural land and reserve or open forests. The barren-lands are constantly increasing and the agricultural land is linearly decreasing. Hence, there is an inverse correlation between barren-lands and agricultural land. Moreover, there is a shift to non-irrigated and less water demanding crops, from more water demanding crops, which is a noticeable adaptation. The surface-water availability is highly dependent on rainfall and/or climatic conditions. It is changing either way in a random fashion based upon the quantity of rainfall occurred in

  1. Co-inoculation with Rhizobium and plant growth promoting rhizobacteria (PGPR for inducing salinity tolerance in mung bean under field condition of semi arid climate

    Muhammad Aamir

    2013-04-01

    Full Text Available Salinity stress severely affects the growth, nodulation and yield of mung bean (Vigna radiata L.. However, its growth can be improved under salinity stress by inoculation/co-inoculation with rhizobia and plant growth promoting rhizobacteria (PGPR containing 1-Aminocyclopropane-1-carboxylic acid (ACC deaminase enzyme. ACC-deaminase containing bacteria regulate the stress induced ethylene production by hydrolyzing the ACC (immediate precursor of ethylene into ammonia and ketobutyric acid, thus improve plant growth by lowering the ethylene level. A study was conducted under salt affected field conditions where pre-isolated strains of Rhizobium and PGPR were used alone as well as in combination for mitigating the salinity stress on growth, nodulation and yield of mung bean by following the randomized complete block design (RCBD. The data were recorded and analyzed statistically to see the difference among treatments.

  2. Performance of Jatropha curcas L. in Semi-arid Zone: Seed Germination, Seedling Growth and Early Field Growth

    Sharif AHAMAD

    2013-05-01

    Full Text Available There is a lack of information on basic agronomic properties of Jatropha curcas L. (jatropha cultivation on the marginal lands in the semi-arids. Evaluation of agronomic performance of identified elite strains of J. curcas in marginal lands would be of paramount importance for addressing gap areas in their agronomic properties and subsequently for harnessing their optimum economic potentials. The present study undertook the task of analysing the growth performance of a high oil bearing elite strain of J. curcas–DARL-2 in degraded land in semi-arid zone of Deccan Plateau, India. While undertaking the assessment of growth performance of elite strain DARL-2, two other native (wild strains (namely AHN-1 and AHN-2 of J. curcas were also considered so that a comparative evaluation could be carried out. The role of gypsum was also investigated on J. curcas in the nursery stage as well its carry over effects on growth performance of transplanted trees in the field. Two types of substrates, gypsum-treated soil (GS and untreated soil (SL were used for growing seedlings of all the three jatropha strains. Seedlings (120-days-old of DARL-2 exhibited greater plant height, collar diameter and number of branches but root length was greater in the local strains. In the second year of field transplantation, DARL-2 strain exhibited significantly (p<0.05 greater plant height and number of branches/plant. No carry over effects of gypsum treatment were observed in field transplanted plants as none of the growth parameters significantly varied among the substrate types.

  3. Medicinal plants in the cultural landscape of a Mapuche-Tehuelche community in arid Argentine Patagonia: an eco-sensorial approach.

    Molares, Soledad; Ladio, Ana

    2014-08-26

    The taste and smell of medicinal plants and their relation to the cultural landscape of a Mapuche-Tehuelche community in the Patagonian steppe was investigated. We assume that the landscapes as a source of therapeutic resources is perceived, classified and named according to different symbolic, ecological and utilitarian criteria which are influenced by chemosensorial appearance of medicinal plants which are valued by inhabitants. Information relating to the cultural landscape experienced by 18 inhabitants, all representing 85% of the families, in terms of medicinal plants, knowledge of species and their organoleptic perception was obtained through participant observation, interviews and free listing. The data were examined using cualitative and quantitative approach, including discourse analysis and non-parametric statistics. Informants use 121 medicinal species, obtained from both wild and non-wild environments, most of which (66%) present aroma and/or taste. It was found that the plants with highest use consensus used for digestive, respiratory, cardio-vascular, analgesic-anti-inflammatory, obstetric-gynaecological and genito-unrinary complaints, have the highest frequencies of cites reporting flavor; and those with the highest frequencies relating to digestive, analgesic-anti-inflammatory and cultural syndromes present the highest frequencies of aroma. Flavor and/or aroma are interpreted as strong or soft, and the strongest are associated with treatment of supernatural ailments. Also, taste is a distinctive trait for the most of the species collected in all natural units of the landscape, while aroma is more closely associated with species growing at higher altitudes. The local pharmacopeia is also enriched with plants that come from more distant phytogeographical environments, such as the Andean forest and the Patagonian Monte, which are obtained through barter with neighboring populations. Herbal products are also obtained in regional shop. The practices of

  4. Lithological and land-use based assessment of heavy metal pollution in soils surrounding a cement plant in SW Europe.

    Cutillas-Barreiro, Laura; Pérez-Rodríguez, Paula; Gómez-Armesto, Antía; Fernández-Sanjurjo, María José; Álvarez-Rodríguez, Esperanza; Núñez-Delgado, Avelino; Arias-Estévez, Manuel; Nóvoa-Muñoz, Juan Carlos

    2016-08-15

    We study the influence of phasing out a cement plant on the heavy metal (Hg, Pb and Cr) content in the surrounding soils, taking into account factors often neglected, such as contributions due to local lithology or land use. The range of total Hg was 10-144µg kg(-1), reaching up to 41 and 145mgkg(-1) for total contents of Pb and Cr, respectively. Forest soils showed higher concentration of Hg than prairie soils, indicating the importance of land use on the accumulation of volatile heavy metals in soils. In forest soils, total Hg showed a trend to decrease with soil depth, whereas in prairie soils the vertical pattern of heavy metal concentrations was quite homogeneous. In most cases, the distance to the cement plant was not a factor of influence in the soils content of the analyzed heavy metals. Total Pb and Cr contents in soils nearby the cement plant were quite similar to those found in the local lithology, resulting in enrichment factor values (EF's) below 2. This suggests that soil parent material is the main source of these heavy metals in the studied soils, while the contribution of the cement plant to Pb and Cr soil pollution was almost negligible. On the contrary, the soils surrounding the cement plant accumulate a significant amount of Hg, compared to the underlying lithology. This was especially noticeable in forest soils, where Hg EF achieved values up to 36. These results are of relevance, bearing in mind that Hg accumulation in soils may be an issue of environmental concern, particularly in prairie soils, where temporal flooding can favor Hg transformation to highly toxic methyl-Hg. In addition, the concurrence of acid soils and total-Cr concentrations in the range of those considered phytotoxic should be also stressed. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. The charophycean green algae as model systems to study plant cell walls and other evolutionary adaptations that gave rise to land plants

    Sørensen, Iben; Rose, Jocelyn K.C.; Doyle, Jeff J.

    2012-01-01

    for terrestrial colonization. The nature and molecular bases of such traits are still being determined, but one critical adaptation is thought to have been the evolution of a complex cell wall. Very little is known about the identity, origins and diversity of the biosynthetic machinery producing the major suites......, during times of radical habitat changes. Orders of the CGA span early diverging taxa retaining more ancestral characters, through complex multicellular organisms with morphological characteristics resembling those of land plants. Examination of gene diversity and evolution within the CGA could help...

  6. Land desertification monitoring and assessment in Yulin of Northwest China using remote sensing and geographic information systems (GIS).

    Zhang, Yuanzhi; Chen, Zhengyi; Zhu, Boqin; Luo, Xiuyue; Guan, Yanning; Guo, Shan; Nie, Yueping

    2008-12-01

    The objective of this study is to develop techniques for assessing and analysing land desertification in Yulin of Northwest China, as a typical monitoring region through the use of remotely sensed data and geographic information systems (GIS). The methodology included the use of Landsat TM data from 1987, 1996 and 2006, supplemented by aerial photos in 1960, topographic maps, field work and use of other existing data. From this, land cover, the Normalised Difference Vegetation Index (NDVI), farmland, woodland and grassland maps at 1:100,000 were prepared for land desertification monitoring in the area. In the study, all data was entered into a GIS using ILWIS software to perform land desertification monitoring. The results indicate that land desertification in the area has been developing rapidly during the past 40 years. Although land desertification has to some extent been controlled in the area by planting grasses and trees, the issue of land desertification is still serious. The study also demonstrates an example of why the integration of remote sensing with GIS is critical for the monitoring of environmental changes in arid and semi-arid regions, e.g. in land desertification monitoring in the Yulin pilot area. However, land desertification monitoring using remote sensing and GIS still needs to be continued and also refined for the purpose of long-term monitoring and the management of fragile ecosystems in the area.

  7. Analysis of yield and plant traits of oilseed rape (Brassica napus L. cultivated in temperate region in light of the possibilities of sowing in arid areas

    Tadeusz Zając

    2016-12-01

    Full Text Available This work is a review of selected literature on the species of Brassica with the greatest economic significance. Oilseed rape (Brassica napus ssp. oleifera currently ranks third worldwide among oilseed crops used for oil production and is the most important in the temperate zone. The manifold uses of rape include not only human consumption of oil, but also the use of post-extraction meal to feed livestock as well as industrial applications as a source of bioenergy or cellulose. The improvement in the economic position of rape among crop plants is also due to the doubling of its yield between 1970 and 2009; the average annual increase in seed yield worldwide was 27 kg ha−1 yr−1. The yield level in Europe exceeds the average yields achieved in the world, particularly in Asia. Recently, the cultivation of oilseed rape was started on a relatively large acreage in Iran where the yield amounted 2.1 t ha−1, exceeding the yields of China and India. In Poland, the acreage of oilseed rape cultivation between 1965 and 2013 increased 3–4 times, and during this period the annual increase in seed yield was 29 kg ha−1 yr−1. Under the field conditions of the temperate climate zone, winter oilseed rape yield is mainly determined by agro-climatic conditions during the growing period, the level of nitrogen fertilization, and the production potential of varieties, which is currently highest in hybrids. There is a noticeable tendency of hybrids towards formation of more siliques by individual oilseed plants. Different production categories of plants appear in a rape crop. Semi-dwarf varieties of winter rapeseed are distinguished by greater silique density, particularly on the main shoot. Moreover, these hybrids are characterized by faster growth of the root system, which enables them to take up nitrogen from the soil more efficiently.

  8. Land-use history affects understorey plant species distributions in a large temperate-forest complex, Denmark

    Svenning, J.-C.; Baktoft, Karen H.; Balslev, Henrik

    2009-01-01

    In Europe, forests have been strongly influenced by human land-use for millennia. Here, we studied the importance of anthropogenic historical factors as determinants of understorey species distributions in a 967 ha Danish forest complex using 156 randomly placed 100-m2 plots, 15 environmental, 9...... dispersal and a strong literature record as ancient-forest species, were still concentrated in areas that were high forest in 1805. Among the younger forests, there were clear floristic differences between those on reclaimed bogs and those not. Apparently remnant populations of wet-soil plants were still...

  9. Impacts of accidental radioactive releases to the hydrosphere from floating and land-based nuclear power plants

    Vollmer, R.H.

    1978-01-01

    To assess the impacts of accidental radioactive releases to the hydrosphere from floating and land-based nuclear power plants, the Liquid Pathway Generic Study was initiated. The objective of this study was to compare the risks associated with releases through the liquid pathway from accidents that may reasonably be expected and those that are very improbable. Consequences were estimated in terms of radiation dose to man from drinking water ingestion, shell-fish and fish flesh consumption, and direct exposure (swimming, beach) as well as long-term effects, such as genetic effects or aquatic species degradation. (author)

  10. Water and radiation use efficiencies of transplanted rice (Oryza sativa L.) at different plant densities and irrigation regimes under semi-arid environment

    Ahmad, S.; Ali, H.; Shad, S.A.; Zia-ul-Haq, M.; Ahmad, A.; Maqsood, M.; Khan, M.B.; Mehmood, S.; Hussain, A.

    2008-01-01

    Growth and yield of rice (Oryza sativa L.), in response to plant densities and irrigation (optimum to stress) were analyzed in terms of interception and utilization of photo-synthetically active radiation (PAR) and water use efficiency (WUE). The amount of PAR intercepted and cumulative evapotranspiration (ET) by each treatment was estimated from the measured leaf area index. The relationships between total dry matter grain yield and accumulated intercepted PAR and cumulative ET were linear. Yield differences among the treatments were attributed to the amount of PAR intercepted and water transpired their efficiencies of utilization or both. The fraction of intercepted radiation and WUE was significantly affected by the plant densities and various irrigation regimes, while, radiation utilization efficiency (RUE) and water use efficiency (WUE) for TDM varied from 1.15 g MJ-1 to 1.36 g MJ-1 and 22.6 kg per ha mm-1 to 24.3 kg per ha mm-1 during both the seasons

  11. Semi-arid Areas

    Livia Bizikova

    precipitation in the form of rainfall or snow (UN, 2011; MEA 2009). • Dryland subtypes can ... in terms of their land uses: rangelands, croplands, and urban areas. ... farmers; climate resilient agricultural practices; irrigation, pasture management.

  12. Cytogenetic features of rRNA genes across land plants: analysis of the Plant rDNA database

    Garcia, S.; Kovařík, Aleš; Leitch, A. R.; Garnatje, T.

    2017-01-01

    Roč. 89, č. 5 (2017), s. 1020-1030 ISSN 0960-7412 R&D Projects: GA ČR(CZ) GC16-02149J Institutional support: RVO:68081707 Keywords : in-situ hybridization * 5s rdna * 45s rdna * concerted evolution Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 5.901, year: 2016

  13. Planting the Seeds of a New Agriculture: Living with the Land in Central America.

    Adriance, Jim

    1995-01-01

    Central America's macroeconomics, land tenure patterns, and population growth are forcing small-scale farmers to alternatives based on farmer-to-farmer teaching and farming in concert with the environment. Discusses major schools of thought that have fueled this phenomenon, and how extension services and isolated groups are joining to form a…

  14. Evaluating the influence of plant-specific physiological parameterizations on the partitioning of land surface energy fluxes

    Sulis, Mauro; Langensiepen, Matthias; Shrestha, Prabhakar; Schickling, Anke; Simmer, Clemens; Kollet, Stefan

    2015-04-01

    Vegetation has a significant influence on the partitioning of radiative forcing, the spatial and temporal variability of soil water and soil temperature. Therefore plant physiological properties play a key role in mediating and amplifying interactions and feedback mechanisms in the soil-vegetation-atmosphere continuum. Because of the direct impact on latent heat fluxes, these properties may also influence weather generating processes, such as the evolution of the atmospheric boundary layer (ABL). In land surface models, plant physiological properties are usually obtained from literature synthesis by unifying several plant/crop species in predefined vegetation classes. In this work, crop-specific physiological characteristics, retrieved from detailed field measurements, are included in the bio-physical parameterization of the Community Land Model (CLM), which is a component of the Terrestrial Systems Modeling Platform (TerrSysMP). The measured set of parameters for two typical European mid-latitudinal crops (sugar beet and winter wheat) is validated using eddy covariance measurements (sensible heat and latent heat) over multiple years from three measurement sites located in the North Rhine-Westphalia region, Germany. We found clear improvements of CLM simulations, when using the crop-specific physiological characteristics of the plants instead of the generic crop type when compared to the measurements. In particular, the increase of latent heat fluxes in conjunction with decreased sensible heat fluxes as simulated by the two new crop-specific parameter sets leads to an improved quantification of the diurnal energy partitioning. These findings are cross-validated using estimates of gross primary production extracted from net ecosystem exchange measurements. This independent analysis reveals that the better agreement between observed and simulated latent heat using the plant-specific physiological properties largely stems from an improved simulation of the

  15. Sporophytes of polysporangiate land plants from the early Silurian period may have been photosynthetically autonomous

    Libertín, M.; Kvaček, J.; Bek, Jiří; Žárský, V.; Štorch, Petr

    2018-01-01

    Roč. 4, 30 April 2018 (2018), s. 269-271 ISSN 2055-026X Institutional support: RVO:67985831 Keywords : earliest vascular plant s * in situ spores * Silurian * polysporangiate plant s Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Paleontology Impact factor: 10.300, year: 2016

  16. Evolution of photorespiration from cyanobacteria to land plants, considering protein phylogenies and acquisition of carbon concentrating mechanisms.

    Hagemann, Martin; Kern, Ramona; Maurino, Veronica G; Hanson, David T; Weber, Andreas P M; Sage, Rowan F; Bauwe, Hermann

    2016-05-01

    Photorespiration and oxygenic photosynthesis are intimately linked processes. It has been shown that under the present day atmospheric conditions cyanobacteria and all eukaryotic phototrophs need functional photorespiration to grow autotrophically. The question arises as to when this essential partnership evolved, i.e. can we assume a coevolution of both processes from the beginning or did photorespiration evolve later to compensate for the generation of 2-phosphoglycolate (2PG) due to Rubisco's oxygenase reaction? This question is mainly discussed here using phylogenetic analysis of proteins involved in the 2PG metabolism and the acquisition of different carbon concentrating mechanisms (CCMs). The phylogenies revealed that the enzymes involved in the photorespiration of vascular plants have diverse origins, with some proteins acquired from cyanobacteria as ancestors of the chloroplasts and others from heterotrophic bacteria as ancestors of mitochondria in the plant cell. Only phosphoglycolate phosphatase was found to originate from Archaea. Notably glaucophyte algae, the earliest branching lineage of Archaeplastida, contain more photorespiratory enzymes of cyanobacterial origin than other algal lineages or land plants indicating a larger initial contribution of cyanobacterial-derived proteins to eukaryotic photorespiration. The acquisition of CCMs is discussed as a proxy for assessing the timing of periods when photorespiratory activity may have been enhanced. The existence of CCMs also had marked influence on the structure and function of photorespiration. Here, we discuss evidence for an early and continuous coevolution of photorespiration, CCMs and photosynthesis starting from cyanobacteria via algae, to land plants. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  17. Paclobutrazol biodegradation in unsaturated soil in the Semi-Arid ...

    Paclobutrazol (PBZ) is a plant growth regulator, increasing flowe ring and yield that is widely used in mango cultivation in the semi-arid northeastern Brazil. PBZ remains active in the soil for several years. However, it can severely affect the growth and development of subsequent crops, mainly by reducing vegetative vigor.

  18. Quantitative Hydraulic Models Of Early Land Plants Provide Insight Into Middle Paleozoic Terrestrial Paleoenvironmental Conditions

    Wilson, J. P.; Fischer, W. W.

    2010-12-01

    Fossil plants provide useful proxies of Earth’s climate because plants are closely connected, through physiology and morphology, to the environments in which they lived. Recent advances in quantitative hydraulic models of plant water transport provide new insight into the history of climate by allowing fossils to speak directly to environmental conditions based on preserved internal anatomy. We report results of a quantitative hydraulic model applied to one of the earliest terrestrial plants preserved in three dimensions, the ~396 million-year-old vascular plant Asteroxylon mackei. This model combines equations describing the rate of fluid flow through plant tissues with detailed observations of plant anatomy; this allows quantitative estimates of two critical aspects of plant function. First and foremost, results from these models quantify the supply of water to evaporative surfaces; second, results describe the ability of plant vascular systems to resist tensile damage from extreme environmental events, such as drought or frost. This approach permits quantitative comparisons of functional aspects of Asteroxylon with other extinct and extant plants, informs the quality of plant-based environmental proxies, and provides concrete data that can be input into climate models. Results indicate that despite their small size, water transport cells in Asteroxylon could supply a large volume of water to the plant's leaves--even greater than cells from some later-evolved seed plants. The smallest Asteroxylon tracheids have conductivities exceeding 0.015 m^2 / MPa * s, whereas Paleozoic conifer tracheids do not reach this threshold until they are three times wider. However, this increase in conductivity came at the cost of little to no adaptations for transport safety, placing the plant’s vegetative organs in jeopardy during drought events. Analysis of the thickness-to-span ratio of Asteroxylon’s tracheids suggests that environmental conditions of reduced relative

  19. Contour hedgerows and grass strips in erosion and runoff control in semi-arid Kenya

    Kinama, J.M.; Stigter, C.J.; Ong, C.K.; Ng'ang'a, J.K.; Gichuki, F.N.

    2007-01-01

    Most early alley cropping studies in semi-arid Kenya were on fairly flat land while there is an increase in cultivated sloping land. The effectiveness of aging contour hedgerows and grass strips for erosion control on an about 15% slope of an Alfisol was compared. The five treatments were Senna

  20. Land-use intensity and host plant simultaneously shape the composition of arbuscular mycorrhizal fungal communities in a Mediterranean drained peatland.

    Ciccolini, Valentina; Ercoli, Laura; Davison, John; Vasar, Martti; Öpik, Maarja; Pellegrino, Elisa

    2016-12-01

    Land-use change is known to be a major threat to biodiversity and ecosystem services in Mediterranean areas. However, the potential for different host plants to modulate the effect of land-use intensification on community composition of arbuscular mycorrhizal fungi (AMF) is still poorly understood. To test the hypothesis that low land-use intensity promotes AMF diversity at different taxonomic scales and to determine whether any response is dependent upon host plant species identity, we characterised AMF communities in the roots of 10 plant species across four land use types of differing intensity in a Mediterranean peatland system. AMF were identified using 454 pyrosequencing. This revealed an overall low level of AMF richness in the peaty soils; lowest AMF richness in the intense cropping system at both virtual taxa and family level; strong modulation by the host plant of the impact of land-use intensification on AMF communities at the virtual taxa level; and a significant effect of land-use intensification on AMF communities at the family level. These findings have implications for understanding ecosystem stability and productivity and should be considered when developing soil-improvement strategies in fragile ecosystems, such as Mediterranean peatlands. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Factors relevant to the decommissioning of land-based nuclear reactor plants

    1980-01-01

    This document applies to all classes of land-based nuclear fission reactors, including those reactors used for the production of electricity or heat, for testing, for research, and for the production of radionuclides. The document covers the technical and administrative aspects related to the conduct of decommissioning, and to the associated radiation protection of man and his environment both during and after decommissioning. The document is intended to provide assistance to those responsible for planning or implementing the decommissioning of a land-based nuclear reactor. The user of this report is further encouraged to review past experience gained with nuclear facilities and the published technical data cited in the section entitled Bibliography

  2. Patterns of plant diversity loss and species turnover resulting from land abandonment and intensification in semi-natural grasslands.

    Uchida, Kei; Koyanagi, Tomoyo F; Matsumura, Toshikazu; Koyama, Asuka

    2018-07-15

    Land-use changes cause biodiversity loss in semi-natural ecosystems worldwide. Biotic homogenization has led to biodiversity loss, mainly through declines in species composition turnover. Elucidating patterns of turnover in species composition could enhance our understanding of how anthropogenic activities affect community assembly. Here, we focused on whether the decreasing patterns in plant diversity and turnover of species composition resulting from land-use change vary in two regions. We estimated the species diversity and composition of semi-natural grasslands surrounding paddy fields in satoyama landscapes. We examined the differences in species diversity and composition across three land-use types (abandoned, traditional, and intensified) in two regions (Hyogo and Niigata Prefectures, Japan), which were characterized by different climatic conditions. We then assessed alpha-, beta-, and gamma-diversity to compare the patterns of diversity losses in the two regions as a result of land-use changes. In each region, gamma-diversity was consistently higher in the traditional sites compared to abandoned or intensified sites. The analyses revealed that most of the beta-diversity in traditional sites differed significantly from those of abandoned and intensified sites in both regions. However, the beta-diversity of total and perennial species did not differ between traditional and abandoned sites in the Hyogo region. We noted that the beta-diversity of total and perennial species in intensified sites was much lower than that in the traditional sites of the Niigata region. Overall, the patterns of alpha- and gamma-diversity loss were similar in both study regions. Although the biotic homogenization was caused by intensified land-use in the Niigata region, this hypothesis did not completely explain the loss of biodiversity in the abandoned sites in the Hyogo region. The present study contributes to the growing body of work investigating changes in biodiversity as a

  3. The rising of the land at the nuclear power plant Asco II

    Garcia Sanchez, J.; Ubalde, L.

    1997-01-01

    The rising of the land on which Asco II is settled is a geological process of slow and falling evolution in the time, studied and followed by means of geophysical models of the underground and continuous auscultation. Their influence on the structures, equipment, components and systems is contemplated in the bases of the design of the power station, whose behaviour towards this phenomenon evolves satisfactorily in accordance with control parameters. (Author)

  4. Modeling gross primary production in semi-arid Inner Mongolia using MODIS imagery and eddy covariance data

    Ranjeet John; Jiquan Chen; Asko Noormets; Xiangming Xiao; Jianye Xu; Nan Lu; Shiping Chen

    2013-01-01

    We evaluate the modelling of carbon fluxes from eddy covariance (EC) tower observations in different water-limited land-cover/land-use (LCLU) and biome types in semi-arid Inner Mongolia, China. The vegetation photosynthesis model (VPM) and modified VPM (MVPM), driven by the enhanced vegetation index (EVI) and land-surface water index (LSWI), which were derived from the...

  5. Phased Restoration Plan for Degraded Land in North Korea by the Clustered Distribution Pattern of Suitable Afforestation Plants

    Lee, S. G.; Lee, W. K.; Choi, H. A.; Yoo, H.; Song, C.; Son, Y.; Cha, S.; Bae, S. W.

    2017-12-01

    Degraded forest of North Korea (DPRK; The Democratic People's Republic of Koprea) is not only confined itself, it could cause serious problem in Korean Peninsula. The importance of restoration for degraded land has increased to improve an healthy ecosystem and solve a shortage of food in North Korea lately. On the other hand, although effort of North Korea government, degraded problem have consistently got worse. There are two main reasons it does not show effectively. The most critical one is absence of technique and information to restore, they concentrate urgent problem which is related to a poor food supply. The other problem is that they demand an efficiency plan in a short period. In these aspect, this study aims selecting suitable tree by spatial characteristics and establishing phased restoration plan to support policy decision about a degraded land in North Korea. The suitable tree for restoration is taken from references which involve natural plant distribution of North and South Korea (ROK; Republic of Korea). Optimal environmental predicted map is deducted from accumulated data of plant physiology whose endemic environmental optimal range individually. It is integrated a map by order of priorities that first is suitable tree species according to the region, and second is clustering distribution rate in a same species. The two types of priority is applied to weighting method. The research result shows that 23 afforestation species fit to restore, and lager distributed plants agree with the major species in Korean Peninsula. The integrated map considers weight of priorities, and it appears that Picea jezoensis is matched the widest. The integrated map shows a view of suitable restoration according to the space, but this is finespun to utilize in a policy. Therefore It provides 3 step plan to support policy decision by Block Statistics, as 12.5km (long-term general plan), 5km (medium-term detailed plan), 1km (short-term implementation plan).

  6. Complete plastome sequences of Equisetum arvense and Isoetes flaccida: implications for phylogeny and plastid genome evolution of early land plant lineages

    Mandoli Dina F

    2010-10-01

    Full Text Available Abstract Background Despite considerable progress in our understanding of land plant phylogeny, several nodes in the green tree of life remain poorly resolved. Furthermore, the bulk of currently available data come from only a subset of major land plant clades. Here we examine early land plant evolution using complete plastome sequences including two previously unexamined and phylogenetically critical lineages. To better understand the evolution of land plants and their plastomes, we examined aligned nucleotide sequences, indels, gene and nucleotide composition, inversions, and gene order at the boundaries of the inverted repeats. Results We present the plastome sequences of Equisetum arvense, a horsetail, and of Isoetes flaccida, a heterosporous lycophyte. Phylogenetic analysis of aligned nucleotides from 49 plastome genes from 43 taxa supported monophyly for the following clades: embryophytes (land plants, lycophytes, monilophytes (leptosporangiate ferns + Angiopteris evecta + Psilotum nudum + Equisetum arvense, and seed plants. Resolution among the four monilophyte lineages remained moderate, although nucleotide analyses suggested that P. nudum and E. arvense form a clade sister to A. evecta + leptosporangiate ferns. Results from phylogenetic analyses of nucleotides were consistent with the distribution of plastome gene rearrangements and with analysis of sequence gaps resulting from insertions and deletions (indels. We found one new indel and an inversion of a block of genes that unites the monilophytes. Conclusions Monophyly of monilophytes has been disputed on the basis of morphological and fossil evidence. In the context of a broad sampling of land plant data we find several new pieces of evidence for monilophyte monophyly. Results from this study demonstrate resolution among the four monilophytes lineages, albeit with moderate support; we posit a clade consisting of Equisetaceae and Psilotaceae that is sister to the "true ferns

  7. Phylogeny and expression analyses reveal important roles for plant PKS III family during the conquest of land by plants and angiosperm diversification

    Lulu Xie

    2016-08-01

    Full Text Available AbstractPolyketide synthases (PKSs utilize the products of primary metabolism to synthesize a wide array of secondary metabolites in both prokaryotic and eukaryotic organisms. PKSs can be grouped into three distinct classes, type I, II, and III, based on enzyme structure, substrate specificity, and catalytic mechanisms. The type III PKS enzymes function as homodimers, and are the only class of PKS that do not require acyl carrier protein. Plant type III PKS enzymes, also known as chalcone synthase (CHS-like enzymes, are of particular interest due to their functional diversity. In this study, we mined type III PKS gene sequences from the genomes of six aquatic algae and twenty-five land plants (one bryophyte, one lycophyte, two basal angiosperms, sixteen core eudicots, and five monocots. PKS III sequences were found relatively conserved in all embryophytes, but not exist in algae. We also examined gene expression patterns by analyzing available transcriptome data, and identified potential cis regulatory elements in upstream sequences. Phylogenetic trees of dicots angiosperms showed that plant type III PKS proteins fall into three clades. Clade A contains CHS/STS-type enzymes coding genes with diverse transcriptional expression patterns and enzymatic functions, while clade B is further divided into subclades b1 and b2, which consist of anther-specific CHS-like enzymes. Differentiation regions, such as amino acids 196-207 between clades A and B, and predicted positive selected sites within α-helixes in late appeared branches of clade A, account for the major diversification in substrate choice and catalytic reaction. The integrity and location of conserved cis-elements containing MYB and bHLH binding sites can affect transcription levels. Potential binding sites for transcription factors such as WRKY, SPL or AP2/EREBP may contribute to tissue- or taxon-specific differences in gene expression. Our data shows that gene duplications and functional

  8. [Effects of planting system on soil and water conservation and crop output value in a sloping land of Southwest China].

    Xiang, Da-Bing; Yong, Tai-Wen; Yang, Wen-Yu; Yu, Xiao-Bo; Guo, Kai

    2010-06-01

    A three-year experiment was conducted to study the effects of wheat/maize/soybean with total no-tillage and mulching (NTM), wheat/maize/soybean with part no-tillage and part mulching (PTM), wheat/maize/soybean with total tillage without mulching (TWM), and wheat/maize/ sweet potato with total tillage without mulching (TWMS) on the soil and water conservation, soil fertility, and crop output value in a sloping land of Southwest China. The average soil erosion amount and surface runoff of NTM were significantly lower than those of the other three planting systems, being 1189 kg x hm(-2) and 215 m3 x hm(-2), and 10.6% and 84.7% lower than those of TWMS, respectively. The soil organic matter, total N, available K and available N contents of NTM were increased by 15.7%, 18.2%, 55.2%, and 25.9%, respectively, being the highest among the test planting systems. PTM and TWM took the second place, and TWMS pattern had the least. NTM had the highest annual crop output value (18809 yuan x hm(-2)) and net income (12619 yuan x hm(-2)) in three years, being 2.2% -20.6% and 3.8% -32.9% higher than other three planting systems, respectively. In a word, the planting system wheat/maize/soybean was more beneficial to the water and soil conservation and the improvement of soil fertility and crop output value, compared with the traditional planting system wheat/maize/sweet potato.

  9. Effect of rooting depth, plant density and planting date on maize (Zea Mays L.) yield and water use efficiency in semi-arid Zimbabwe: Modelling with AquaCrop

    Nyakudya, I.W.; Stroosnijder, L.

    2014-01-01

    Under low and poorly distributed rainfall higher food production can be achieved by increasing crop water use efficiency (WUE) through optimum soil fertility management and selection of deep-rooting cultivars, appropriate plant density and planting dates. We explored AquaCrop's applicability in

  10. Herbaceous land plants as a renewable energy source for Puerto Rico

    Alexander, A.G.

    1980-01-01

    Herbaceous tropical plants are a renewable energy source of major importance to many tropical nations. They convert the radiant energy of sunlight to chemical energy, which is stored in plant tissues (cellulose, hemicellulose, lignin) and fermentable solids (sugars, starches). Because all tropical plants do this - even those commonly regarded as weeds - they constitute an inexpensive, renewable, and domestic alternative to foreign fossil energy. The vast majority of herbaceous tropical plants have never been cultivated for food, fiber, or energy. A major screening program would be needed to identify superior species and the most effective roles they can play in a domestic energy industry. Other herbaceous plants, such as sugarcane and tropical forage grasses, have been cultivated for centuries as agricultural commodities. As energy crops, important revisions in management will be needed to maximize their energy yield. Two broad groups of herbaceous plants are seen to have an immediate potential for reducing Puerto Rico's reliance on imported fossil fuels: the tropical grasses (of which sugarcane is the dominant member) and the tropical legumes. Managed for its maximum growth potential, sugarcane is an excellent source of boiler fuel, fermentation substrates, cellulosic feedstocks, and the sweetener sucrose. Other tropical grasses store relatively little extractable sugar while equaling or moderately surpassing sugarcane in yield of cellulosic dry matter. The latter might soon become an economical source of fermentation substrates. Certain legume species are also very effective producers of biomass. Herbaceous tropical legumes are perceived as a potential source of biological nitrogen for energy crops unable to utilize nitrogen from the atmosphere.

  11. Herbaceous land plants as a renewable energy source for Puerto Rico

    Alexander, A G

    1980-01-01

    Herbaceous tropical plants are a renewable energy source of major importance to many tropical nations. They convert the radiant energy of sunlight to chemical energy, which is stored in plant tissues (cellulose, hemicellulose, lignin) and fermentable solids (sugars, starches). Because all tropical plants do this - even those commonly regarded as weeds - they constitute an inexpensive, renewable, and domestic alternative to foreign fossil energy. The vast majority of herbaceous tropical plants have never been cultivated for food, fiber, or energy. A major screening program would be needed to identify superior species and the most effective roles they can play in a domestic energy industry. Other herbaceous plants, such as sugarcane and tropical forage grasses, have been cultivated for centuries as agricultural commodities. As energy crops, important revisions in management will be needed to maximize their energy yield. Two broad groups of herbaceous plants are seen to have an immediate potential for reducing Puerto Rico's reliance on imported fossil fuels: the tropical grasses (of which sugarcane is the dominant member) and the tropical legumes. Managed for its maximum growth potential, sugarcane is an excellent source of boiler fuel, fermentation substrates, cellulosic feedstocks, and the sweetener sucrose. Other tropical grasses store relatively little extractable sugar while equaling or moderately surpassing sugarcane in yield of cellulosic dry matter. The latter might soon become an economical source of fermentation substrates. Certain legume species are also very effective producers of biomass. Herbaceous tropical legumes are perceived as a potential source of biological nitrogen for energy crops unable to utilize nitrogen from the atmosphere.

  12. Model Optimization Planting Pattern Agroforestry Forest Land Based on Pine Tree

    Rajati, Tati

    2015-01-01

    This study aims to determine cropping patterns in class slopes 0 - 30%. The method used in this study is a description of the dynamic system approach using a software power sim. Forest areas where the research, which is a type of plant that is cultivated by the people in the study…

  13. Evaluating subsoiling and herbaceous weed control on shortleaf pine planted in retired farm land

    John D. Kushla

    2010-01-01

    In March 2005, shortleaf pine was planted on retired fields of the Mississippi Agriculture and Forestry Experiment Station in Holly Springs. The objectives were to evaluate subsoiling and herbaceous weed control on first year seedling stocking, survival, and size. First year seedling measurements were made on stocking, survival, and size. Only results for first year...

  14. Water requirement and use by Jatropha curcas in a semi-arid tropical location

    Kesava Rao, A.V.R.; Wani, Suhas P.; Singh, Piara; Srinivas, K.; Srinivasa Rao, Ch.

    2012-01-01

    Increasing emphasis on biofuel to meet the growing energy demand while reducing emissions of greenhouse gases, Jatropha curcas has attracted the attention of researchers, policy makers and industries as a good candidate for biodiesel. It is a non-edible oil crop, drought tolerant and could be grown on degraded lands in the tropics without competing for lands currently used for food production. J. curcas being a wild plant, much about its water requirement and production potential of promising clones in different agroclimatic conditions is not known. Water use assessment of J. curcas plantations in the semi-arid tropical location at ICRISAT, Patancheru indicated that crop evapotranspiration of J. curcas under no moisture stress varied from 1410 to 1538 mm per year during 2006–2009. Under field conditions the crop evapotranspiration varied from 614 to 930 mm depending on the atmospheric demand, rainfall and crop phenological stage. Patterns of soil-water depletion indicated that with growing plant age from two to five years, depth of soil-water extraction increased from 100 to 150 cm by fifth year. Monthly water use of Jatropha varied from 10–20 (leaf shedding period) to 140 mm depending on water availability and environmental demand. This study indicated that J. curcas has a good drought tolerance mechanism, however under favorable soil moisture conditions Jatropha could use large amounts of water for luxurious growth and high yield. These findings highlight the need to carefully identify suitable niche areas for Jatropha cultivation and assess the implications of large J. curcas plantations on water availability and use under different agroecosystems, particularly so in water scarce regions such as semi-arid and arid regions in the tropics. -- Highlights: ► Jatropha ET varied from 1410 to 1538 mm in optimal and 614 to 930 mm in field conditions. ► Depth of soil-water extraction increased from 100 to 150 cm by fifth year of age. ► Jatropha yields varied

  15. Assessment of unsaturated zone transport for shallow land burial of radioactive waste: summary report of technology needs, model verification, and measurement efforts (FY 1978 to FY 1983)

    Jones, T.L.; Gee, G.W.

    1984-01-01

    Two main topics are addressed in this report. The first topic relates to the assessment process for shallow land burial site design. This overview includes basic descriptions of water balance, transport processes and technology needs for waste management at an arid (dry) site. The second topic deals with specific results of research activities at PNL related to water and radionuclide transport under arid, shallow land burial conditions. Technology needs at arid-zone (dry) sites are summarized and unique features of radionuclide disposal at dry sites are explained. The report emphasizes the need to understand the interaction between climate, soil, plants, engineered barriers, and buried waste in order to evaluate performance of a waste disposal system at a dry site. Water balance data, collected since FY 1978 at the Buried Waste Test Facility (BWTF) at Hanford, are used to illustrate the influence of climate variables (rainfall distribution patterns and evaporative conditions) on soil water storage and drainage at an arid site. For dry site conditions, with no vegetation and coarse soil, significant deep drainage was measured. Deep drainage below the root zone was also measured at a grass-covered site on the Hanford site after early spring rains, which emphasizes the need to carefully monitor site water balances even at arid (dry) sites. The monitoring technology, water balance, and radionuclide transport at arid sites are discussed, and the use of neutron probes, electrical resistance units, tensiometers, and psychrometers are explained, and examples are given on their applications in arid-site monitoring. Measurements of water flow and radionuclide transport coefficients needed to describe movement in unsaturated soils are documented. 40 references, 21 figures, 5 tables

  16. An ecological engineering approach for keeping water from reaching interred wastes in arid or semiarid regions

    Anderson, J.E.

    1997-01-01

    This paper describes application of a soil-plant cover system (SPCS) to preclude water from reaching interred wastes in arid and semiarid regions. Where potential evapotranspiration far exceeds precipitation, water can be kept from reaching buried wastes by (1) providing a sufficiently deep cap of soil to store precipitation that falls while plants are dormant and (2) maintaining plant cover to deplete soil moisture during the growing season, thereby emptying the storage reservoir. Research at the Idaho National Engineering Laboratory (INEL) has shown that 2 m of soil is adequate to store moisture from snowmelt and spring rains. Healthy stands of perennial grasses and shrubs adapted to the INEL climate use all available soil moisture, even during a very wet growing season. However, burrowing by small mammals or ants may affect the performance of a SPCS by increasing infiltration of water. Intrusion barriers of gravel and cobble can be used to restrict burrowing, but emplacement of such barriers affects soil moisture storage and plant rooting depths. A replicated field experiment to investigate the implications of those effects is in progress. Incorporation of an SPCS should be considered in the design of isolation barriers for shallow land burial of hazardous wastes in and regions

  17. Land use of drained peatlands: Greenhouse gas fluxes, plant production, and economics.

    Kasimir, Åsa; He, Hongxing; Coria, Jessica; Nordén, Anna

    2017-10-10

    Drained peatlands are hotspots for greenhouse gas (GHG) emissions, which could be mitigated by rewetting and land use change. We performed an ecological/economic analysis of rewetting drained fertile peatlands in a hemiboreal climate using different land use strategies over 80 years. Vegetation, soil processes, and total GHG emissions were modeled using the CoupModel for four scenarios: (1) business as usual-Norway spruce with average soil water table of -40 cm; (2) willow with groundwater at -20 cm; (3) reed canary grass with groundwater at -10 cm; and (4) a fully rewetted peatland. The predictions were based on previous model calibrations with several high-resolution datasets consisting of water, heat, carbon, and nitrogen cycling. Spruce growth was calibrated by tree-ring data that extended the time period covered. The GHG balance of four scenarios, including vegetation and soil, were 4.7, 7.1, 9.1, and 6.2 Mg CO 2 eq ha -1  year -1 , respectively. The total soil emissions (including litter and peat respiration CO 2 + N 2 O + CH 4 ) were 33.1, 19.3, 15.3, and 11.0 Mg CO 2 eq ha -1  year -1 , respectively, of which the peat loss contributed 35%, 24%, and 7% of the soil emissions for the three drained scenarios, respectively. No peat was lost for the wet peatland. It was also found that draining increases vegetation growth, but not as drastically as peat respiration does. The cost-benefit analysis (CBA) is sensitive to time frame, discount rate, and carbon price. Our results indicate that the net benefit was greater with a somewhat higher soil water table and when the peatland was vegetated with willow and reed canary grass (Scenarios 2 and 3). We conclude that saving peat and avoiding methane release using fairly wet conditions can significantly reduce GHG emissions, and that this strategy should be considered for land use planning and policy-making. © 2017 John Wiley & Sons Ltd.

  18. Mapping paddy rice planting areas through time series analysis of MODIS land surface temperature and vegetation index data.

    Zhang, Geli; Xiao, Xiangming; Dong, Jinwei; Kou, Weili; Jin, Cui; Qin, Yuanwei; Zhou, Yuting; Wang, Jie; Menarguez, Michael Angelo; Biradar, Chandrashekhar

    2015-08-01

    Knowledge of the area and spatial distribution of paddy rice is important for assessment of food security, management of water resources, and estimation of greenhouse gas (methane) emissions. Paddy rice agriculture has expanded rapidly in northeastern China in the last decade, but there are no updated maps of paddy rice fields in the region. Existing algorithms for identifying paddy rice fields are based on the unique physical features of paddy rice during the flooding and transplanting phases and use vegetation indices that are sensitive to the dynamics of the canopy and surface water content. However, the flooding phenomena in high latitude area could also be from spring snowmelt flooding. We used land surface temperature (LST) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor to determine the temporal window of flooding and rice transplantation over a year to improve the existing phenology-based approach. Other land cover types (e.g., evergreen vegetation, permanent water bodies, and sparse vegetation) with potential influences on paddy rice identification were removed (masked out) due to their different temporal profiles. The accuracy assessment using high-resolution images showed that the resultant MODIS-derived paddy rice map of northeastern China in 2010 had a high accuracy (producer and user accuracies of 92% and 96%, respectively). The MODIS-based map also had a comparable accuracy to the 2010 Landsat-based National Land Cover Dataset (NLCD) of China in terms of both area and spatial pattern. This study demonstrated that our improved algorithm by using both thermal and optical MODIS data, provides a robust, simple and automated approach to identify and map paddy rice fields in temperate and cold temperate zones, the northern frontier of rice planting.

  19. Field Sampling Plan for Closure of the Central Facilities Area Sewage Treatment Plant Lagoon 3 and Land Application Area

    Lewis, Michael George

    2016-01-01

    This field sampling plan describes sampling of the soil/liner of Lagoon 3 at the Central Facilities Area Sewage Treatment Plant. The lagoon is to be closed, and samples obtained from the soil/liner will provide information to determine if Lagoon 3 and the land application area can be closed in a manner that renders it safe to human health and the environment. Samples collected under this field sampling plan will be compared to Idaho National Laboratory background soil concentrations. If the concentrations of constituents of concern exceed the background level, they will be compared to Comprehensive Environmental Response, Compensation, and Liability Act preliminary remediation goals and Resource Conservation and Recovery Act levels. If the concentrations of constituents of concern are lower than the background levels, Resource Conservation and Recovery Act levels, or the preliminary remediation goals, then Lagoon 3 and the land application area will be closed. If the Resource Conservation and Recovery Act levels and/or the Comprehensive Environmental Response, Compensation, and Liability Act preliminary remediation goals are exceeded, additional sampling and action may be required.

  20. Field Sampling Plan for Closure of the Central Facilities Area Sewage Treatment Plant Lagoon 3 and Land Application Area

    Lewis, Michael George [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-10-01

    This field sampling plan describes sampling of the soil/liner of Lagoon 3 at the Central Facilities Area Sewage Treatment Plant. The lagoon is to be closed, and samples obtained from the soil/liner will provide information to determine if Lagoon 3 and the land application area can be closed in a manner that renders it safe to human health and the environment. Samples collected under this field sampling plan will be compared to Idaho National Laboratory background soil concentrations. If the concentrations of constituents of concern exceed the background level, they will be compared to Comprehensive Environmental Response, Compensation, and Liability Act preliminary remediation goals and Resource Conservation and Recovery Act levels. If the concentrations of constituents of concern are lower than the background levels, Resource Conservation and Recovery Act levels, or the preliminary remediation goals, then Lagoon 3 and the land application area will be closed. If the Resource Conservation and Recovery Act levels and/or the Comprehensive Environmental Response, Compensation, and Liability Act preliminary remediation goals are exceeded, additional sampling and action may be required.

  1. Initial hydrological modelling to assess impacts of different land uses on process hydrology in a small-scale semi-arid catchment in the Western Cape Province, South Africa

    Steudel, T

    2010-06-01

    Full Text Available in those areas. GIS DATA ? highly precise GPS field measurements and contour line information for digital elevation model (DEM) generation and watershed derivation ? different raster layers (spatial resolution = 7.6 m) containing plot specific...2000 is capable of representing the hydrological conditions within such a small- scale catchment (Fig. 5, Fig 6) OUTLOOK ? J2000 can be used for a detailed analysis of the individual hydrological components affected by land use change ? further...

  2. Lusus naturae:climate and invasions of plant pathogens modify agricultural and forest lands

    Salvatore Moricca

    2009-10-01

    Full Text Available The ecological and economic sustainability of agricultural and forest systems of many advanced and underdeveloped Countries are strongly threatened by the increasing introduction of exotic plant pathogens. This article provides an overview of the main causes behind these invasions. Some important diseases caused by non native phytopathogens, whose arrival in the past century had a disastrous impact on the environment and economy of vast rural areas of our Country are reported. Some dangerous, emerging pathogens, which are literally destroying whole territories in various parts of the Planet, with severe damage to agricultural crops, landscape, economy and local tourism are also reported. Action strategies to prevent immigration of unwanted pathogens, and mitigation strategies, aimed at the development of various measures to mitigate the negative effects of plant parasites already established in the territory are then discussed. Finally, it is highlighted how such a far-reaching problem can be properly tackled only with the active contribution of governments, institutions responsible for plant health monitoring (warning services, research, and agricultural, tourism and transport operators.

  3. Forensic botany II, DNA barcode for land plants: Which markers after the international agreement?

    Ferri, G; Corradini, B; Ferrari, F; Santunione, A L; Palazzoli, F; Alu', M

    2015-03-01

    The ambitious idea of using a short piece of DNA for large-scale species identification (DNA barcoding) is already a powerful tool for scientists and the application of this standard technique seems promising in a range of fields including forensic genetics. While DNA barcoding enjoyed a remarkable success for animal identification through cytochrome c oxidase I (COI) analysis, the attempts to identify a single barcode for plants remained a vain hope for a longtime. From the beginning, the Consortium for the Barcode of Life (CBOL) showed a lack of agreement on a core plant barcode, reflecting the diversity of viewpoints. Different research groups advocated various markers with divergent set of criteria until the recent publication by the CBOL-Plant Working Group. After a four-year effort, in 2009 the International Team concluded to agree on standard markers promoting a multilocus solution (rbcL and matK), with 70-75% of discrimination to the species level. In 2009 our group firstly proposed the broad application of DNA barcoding principles as a tool for identification of trace botanical evidence through the analysis of two chloroplast loci (trnH-psbA and trnL-trnF) in plant species belonging to local flora. Difficulties and drawbacks that were encountered included a poor coverage of species in specific databases and the lack of authenticated reference sequences for the selected markers. Successful preliminary results were obtained providing an approach to progressively identify unknown plant specimens to a given taxonomic rank, usable by any non-specialist botanist or in case of a shortage of taxonomic expertise. Now we considered mandatory to update and to compare our previous findings with the new selected plastid markers (matK+rbcL), taking into account forensic requirements. Features of all the four loci (the two previously analyzed trnH-psbA+trnL-trnF and matK+rbcL) were compared singly and in multilocus solutions to assess the most suitable combination for

  4. The Limits of Acclimation of land plants in a Terrestrial Ecosystems Model

    Kothavala, Zavareh

    2014-05-01

    In this study, we examine the role of the terrestrial carbon cycle and the ability of different plant types to acclimate to a changing climate at the centennial scale using a global ecosystems model with updated biogeochemical processes related to moisture, carbon, and nitrogen. Elevated level of atmospheric carbon dioxide (CO2) increases CO2 fertilization, resulting in more CO2 uptake by vegetation, whereas the concomitant warming increases autotrophic and heterotrophic respiration, releasing CO2 to the atmosphere. Additionally, warming will enhance photosynthesis if current temperatures are below the optimal temperature for plant growth, while it will reduce photosynthesis if current temperatures are above the optimal temperature for plant growth. We present a series of ensemble simulations to evaluate the ability of plants to acclimate to changing conditions over the last century and how this affects the terrestrial carbon sink. A set of experiments related to (a) the varying relationship between CO2 fertilization and the half saturation constant, (b) the factors related to gross primary productivity and maintenance respiration, and (c) the variables related to heterotrophic respiration, were conducted with thirteen plant functional types. The experiments were performed using the Terrestrial Ecosystem Model (TEM) with a present-day vegetation distribution without the effects of natural or human disturbance, and a closed Nitrogen cycle, at a half-degree resolution over the globe. The experiment design consisted of eight scenarios that are consistent with past and future ecosystem conditions, presented in other scientific studies. The significance of model trends related to runoff, soil moisture, soil carbon, Net Primary Productivity (NPP), crop yield, and Net Ecosystem Productivity (NEP) for different seasons, as well as surface temperature, precipitation, vapor pressure, and photosynthetically active radiation are analyzed for various ecosystems at the global

  5. Prosopis for planting in arid zones

    Raina, A.K.

    1984-01-01

    Brief notes are given on the performance at age seven years of seven provenances of Prosopis juliflora at two sites in Rajasthan and on the distribution, habit and possible uses of ecotypes of Prosopis cineraria.

  6. Atmospheric Oxygen Concentrations for the Past 350 Myr Modeled from the δ13C of C3 Land Plants

    Nordt, L.; Breecker, D.

    2016-12-01

    Numerous studies have focused on the systematic collection of long-term d13C records from marine sediments, but no such isotopic compilation exists for C3 land plants. Consequently, we gathered a meta-data base of 8003 plant-derived δ13C values (ISOORG) from various carbon sources binned into 5 myr time steps. The results of this investigation were reported in a recent publication showing that most δ13C sources co-vary with ten CIEs during the last 400 myr. For this paper we culled ISOORG to produce ISOORG16-H that contains 7025 plant-derived δ13C values from paleo-moist environments to reflect secular controls on the δ13C of C3 plants. We then constructed atmospheric pO2 curves for the past 350 myr using prior experimental work showing a direct relationship between the Δ13C of C3 plants and pO2 concentration. Periods of hyperoxia (25-30% pO2) were identified from 300-250, 225-190, and 110-105 myr, and intervals of hypoxia (10-15% pO2) from 350-345, 245-230, and 185-115 myr. During the last 150 myr, pO2 stabilized at 17-24% except for a notable positive excursion from 110-105 myr. Hyperoxia, apparently from widespread carbon burial, supports the notion of insect gigantism during the Late Paleozoic. Hypoxia during the early Triassic correlates with the coal gap following the collapse of Paleozoic ecosystems. Rising pO2 in the late Triassic seems to reflect renewed carbon burial from reorganization of Mesozoic ecosystems. The middle Mesozoic is characterized by low pO2 during an intense greenhouse interval, with ambient conditions ensuing thereafter possibly linked to carbon burial from the radiation of angiosperms. pO2 concentrations >14% suggest wildfires persisted through the study interval except possibly at 160 and 140 myr. Intervals of low pO2 concentration were likely accompanied by lower atmospheric pressure and higher temperatures, particularly from 245-230 myr and 180-120 myr. Our O2 reconstructions conform with GEOCARBSULF, but not with proxy

  7. Comparison of Desertification Intensity in the Purified Wastewater Irrigated Lands with Normal Lands in Yazd Using of Soil Criterion of the IMDPA Model

    M. Yektafar; M. Zare; M. Akhavan Ghalibaf; S. R. Mahdavi Ardakani

    2016-01-01

    Introduction: Desertification, is a complex phenomenon, which as environmental, socio-economical, and cultural impacts on natural resources. According to the United Nations Convention to Combat Desertification defination, desertification is land degradation in arid, semi-arid, and dry sub-humid regions, resulting from climate change and human activities. Because of limiting access to qualified water resources in arid lands, it is necessary to use, all forms of acceptable water resources such ...

  8. Assessment of the Current State of Agropastoral Landscapes in Semi-Arid Areas of the Republic of Kalmykia with Application of Gis-Technologies

    Mushaeva Kermen Batnasunovna

    2015-04-01

    Full Text Available The state of lands in arid areas of southern Russia is entirely dependent on the state of natural steppe, dry steppe and semi-desert ecosystems. The study of vegetation traditionally enjoys a commanding position in synecological studies, because plant communities form the framework of terrestrial ecosystems. In this paper we give a detailed geobothanical description of the test plots made as a result of field research in the semi-desert areas of Kalmykia. In addition, we obtained photo samples of soils that were subsequently processed, analyzed and entered into the database of soils and used as an identifier of rangeland degradation, located in the semi-arid zone of the country. The creation of this database will improve the quality of remote sensing in the region. In the course of computer processing of materials using GIS technology, the geoinformation analysis of land degradation in the studied territory was held, and the area of these lands according to the levels of degradation was calculated.

  9. Spatio-temporal topsoil organic carbon mapping of a semi-arid Mediterranean region: The role of land use, soil texture, topographic indices and the influence of remote sensing data to modelling

    Schillaci, Calogero

    2017-06-02

    SOC is the most important indicator of soil fertility and monitoring its space-time changes is a prerequisite to establish strategies to reduce soil loss and preserve its quality. Here we modelled the topsoil (0–0.3m) SOC concentration of the cultivated area of Sicily in 1993 and 2008. Sicily is an extremely variable region with a high number of ecosystems, soils, and microclimates. We studied the role of time and land use in the modelling of SOC, and assessed the role of remote sensing (RS) covariates in the boosted regression trees modelling. The models obtained showed a high pseudo-R2 (0.63–0.69) and low uncertainty (s.d.<0.76gCkg−1 with RS, and <1.25gCkg−1 without RS). These outputs allowed depicting a time variation of SOC at 1arcsec. SOC estimation strongly depended on the soil texture, land use, rainfall and topographic indices related to erosion and deposition. RS indices captured one fifth of the total variance explained, slightly changed the ranking of variance explained by the non-RS predictors, and reduced the variability of the model replicates. During the study period, SOC decreased in the areas with relatively high initial SOC, and increased in the area with high temperature and low rainfall, dominated by arables. This was likely due to the compulsory application of some Good Agricultural and Environmental practices. These results confirm that the importance of texture and land use in short-term SOC variation is comparable to climate. The present results call for agronomic and policy intervention at the district level to maintain fertility and yield potential. In addition, the present results suggest that the application of RS covariates enhanced the modelling performance.

  10. Spatio-temporal topsoil organic carbon mapping of a semi-arid Mediterranean region: The role of land use, soil texture, topographic indices and the influence of remote sensing data to modelling.

    Schillaci, Calogero; Acutis, Marco; Lombardo, Luigi; Lipani, Aldo; Fantappiè, Maria; Märker, Michael; Saia, Sergio

    2017-12-01

    SOC is the most important indicator of soil fertility and monitoring its space-time changes is a prerequisite to establish strategies to reduce soil loss and preserve its quality. Here we modelled the topsoil (0-0.3m) SOC concentration of the cultivated area of Sicily in 1993 and 2008. Sicily is an extremely variable region with a high number of ecosystems, soils, and microclimates. We studied the role of time and land use in the modelling of SOC, and assessed the role of remote sensing (RS) covariates in the boosted regression trees modelling. The models obtained showed a high pseudo-R 2 (0.63-0.69) and low uncertainty (s.d.<0.76gCkg -1 with RS, and <1.25gCkg -1 without RS). These outputs allowed depicting a time variation of SOC at 1arcsec. SOC estimation strongly depended on the soil texture, land use, rainfall and topographic indices related to erosion and deposition. RS indices captured one fifth of the total variance explained, slightly changed the ranking of variance explained by the non-RS predictors, and reduced the variability of the model replicates. During the study period, SOC decreased in the areas with relatively high initial SOC, and increased in the area with high temperature and low rainfall, dominated by arables. This was likely due to the compulsory application of some Good Agricultural and Environmental practices. These results confirm that the importance of texture and land use in short-term SOC variation is comparable to climate. The present results call for agronomic and policy intervention at the district level to maintain fertility and yield potential. In addition, the present results suggest that the application of RS covariates enhanced the modelling performance. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. To make a land use inventory and its change with time and development. To investigate how this area in the semi-arid climate is developing, and the ecological impact with the construction of several government projects in Central Mexico

    Acoustadelcampo, C. (Principal Investigator)

    1974-01-01

    The author has identified the following significant results. Comparison between ERTS-1 image scale 1:1,000,000 and CETENAL's charts scale 1:50,000 in irrigated land surface determination in one selected spot gave the following results: Surface on CETENAL's charts 129,900 Has. and arbitrarily we gave 100 percent to this value. Surface on image 122,400 Has., 94.5 percent of the first value. It is necessary to use all four bands to have optimum results on the interpretation. The Principal investigator made use of photointerpretation techniques only, mostly monoscopically.

  12. ARID1B is a specific vulnerability in ARID1A-mutant cancers.

    Helming, Katherine C; Wang, Xiaofeng; Wilson, Boris G; Vazquez, Francisca; Haswell, Jeffrey R; Manchester, Haley E; Kim, Youngha; Kryukov, Gregory V; Ghandi, Mahmoud; Aguirre, Andrew J; Jagani, Zainab; Wang, Zhong; Garraway, Levi A; Hahn, William C; Roberts, Charles W M

    2014-03-01

    Recent studies have revealed that ARID1A, encoding AT-rich interactive domain 1A (SWI-like), is frequently mutated across a variety of human cancers and also has bona fide tumor suppressor properties. Consequently, identification of vulnerabilities conferred by ARID1A mutation would have major relevance for human cancer. Here, using a broad screening approach, we identify ARID1B, an ARID1A homolog whose gene product is mutually exclusive with ARID1A in SWI/SNF complexes, as the number 1 gene preferentially required for the survival of ARID1A-mutant cancer cell lines. We show that loss of ARID1B in ARID1A-deficient backgrounds destabilizes SWI/SNF and impairs proliferation in both cancer cells and primary cells. We also find that ARID1A and ARID1B are frequently co-mutated in cancer but that ARID1A-deficient cancers retain at least one functional ARID1B allele. These results suggest that loss of ARID1A and ARID1B alleles cooperatively promotes cancer formation but also results in a unique functional dependence. The results further identify ARID1B as a potential therapeutic target for ARID1A-mutant cancers.

  13. Contrasting land uses in Mediterranean agro-silvo-pastoral systems generated patchy diversity patterns of vascular plants and below-ground microorganisms.

    Bagella, Simonetta; Filigheddu, Rossella; Caria, Maria Carmela; Girlanda, Mariangela; Roggero, Pier Paolo

    2014-12-01

    The aims of this paper were (i) to define how contrasting land uses affected plant biodiversity in Mediterranean agro-silvo-pastoral-systems across a gradient of disturbance regimes: cork oak forests, secondary grasslands, hay crops, grass covered vineyards, tilled vineyards; (ii) to determine whether these patterns mirrored those of below-ground microorganisms and whether the components of γ-diversity followed a similar model. The disturbance regimes affected plant assemblage composition. Species richness decreased with increasing land use intensity, the Shannon index showed the highest values in grasslands and hay crops. Plant assemblage composition patterns mirrored those of Basidiomycota and Ascomycota. Richness in Basidiomycota, denitrifying bacteria and microbial biomass showed the same trend as that observed for vascular plant richness. The Shannon index pattern of below-ground microorganisms was different from that of plants. The plant γ-diversity component model weakly mirrored those of Ascomycota. Patchy diversity patterns suggest that the maintenance of contrasting land uses associated with different productions typical of agro-silvo-pastoral-systems can guarantee the conservation of biodiversity. Copyright © 2014 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  14. Retreating or standing: Responses of forest species and steppe species to climate change in arid eastern central Asia

    Hong-Xiang Zhang; Ming-Li Zhang; Stewart C. Sanderson

    2013-01-01

    The temperature in arid Eastern Central Asia is projected to increase in the future, accompanied by increased variability of precipitation. To investigate the impacts of climate change on plant species in this area, we selected two widespread species as candidates, Clematis sibirica and C. songorica, from montane coniferous forest and arid steppe habitats respectively...

  15. Fibonacci spirals in a brown alga [Sargassum muticum (Yendo Fensholt] and in a land plant [Arabidopsis thaliana (L. Heynh.]: a case of morphogenetic convergence

    Alexis Peaucelle

    2016-12-01

    Full Text Available In this article, the morphology of a brown alga is revisited and compared to the phyllotaxis of land plants. The alga, Sargassum muticum (Yendo Fensholt has a highly organized thallus with a stipe, the stem-like main axis, and hierarchically organized lateral branches of successive orders. Around each of these axes, the lateral organs: blades, side-branches, and receptacles grow in a spiral disposition. As in land plants, this organization is related to an apical mode of growth. Measurements performed along the mature differentiated axes as well as in their meristematic regions confirm the similarity of the large-scale organization of this brown alga with that of the land plants. In particular, the divergence angle between successive elements has similar values and it results from the existence around the meristem of parastichies having the same Fibonacci ordering. This is remarkable in view of the fact that brown algae (Phaeophyceae and land plants (Embryophyta are two clades that diverged approximately 1800 million years ago when they were both unicellular organisms. We argue that the observed similarity results from a morphogenetic convergence. This is in strong support of the genericity and robustness of self-organization models in which similar structures, here Fibonacci related spirals, can be obtained in various situations in which the genetic and physiological implementation of development can be of a different nature.

  16. Evolution of Asian Interior Arid-Zone Biota: Evidence from the Diversification of Asian Zygophyllum (Zygophyllaceae)

    Li, Hong-Lei; Yu, Sheng-Xiang; Zhang, Lin-Jing; Wang, Wei

    2015-01-01

    The Asian interior arid zone is the largest desert landform system in the Northern Hemisphere, and has high biodiversity. Little is currently known about the evolutionary history of its biota. In this study, we used Zygophyllum, an important and characteristic component of the Asian interior arid zone, to provide new insights into the evolution of this biota. By greatly enlarged taxon sampling, we present the phylogenetic analysis of Asian Zygophyllum based on two plastid and one nuclear markers. Our phylogenetic analyses indicate that Asian Zygophyllum and Sarcozygium form a clade and Sarcozygium is further embedded within the shrub subclade. An integration of phylogenetic, biogeographic, and molecular dating methods indicates that Zygophyllum successfully colonized the Asian interior from Africa in the early Oligocene, and Asian Zygophyllum became differentiated in the early Miocene and underwent a burst of diversification in the late Miocene associated with the expansion of Asian interior arid lands due to orogenetic and climatic changes. Combining diversification patterns of other important components of the Asian interior arid zone, we propose a multi-stage evolution model for this biota: the late Eocene–early Oligocene origin, the early Miocene expansion, and the middle-late Miocene rapid expansion to the whole Asian interior arid zone. This study also demonstrates that, for Zygophyllum and perhaps other arid-adapted organisms, arid biomes are evolutionary cradles of diversity. PMID:26393796

  17. Comparison of long-term stability of containment systems for residues and wastes contaminated with naturally occurring radionuclides at an arid site and two humid sites

    Winters, M.; Merry-Libby, P.; Hinchman, R.

    1985-01-01

    The long-term stability of near-surface containment systems designed for the management of radioactive wastes and residues contaminated with naturally occurring radionuclides are compared at the three different sites. The containment designs are: (1) a diked 8.9-m high mound, including a 3.2-m layered cap at a site (humid) near Lewiston, New York, (2) a 6.8-m-high mound, including a similar 3.2-m cap at a site (humid) near Oak Ridge, Tennessee, and (3) 4.8-m deep trenches with 3.0-m backfilled caps at a site (arid) near Hanford, Washington. Geological, hydrological, and biological factors affecting the long-term (1000-year) integrity of the containment systems at each site are examined, including: erosion, flooding, drought, wildfire, slope and cover failure, plant root penetration, burrowing animals, other soil-forming processes, and land-use changes. For the containment designs evaluated, releases of radon-222 at the arid site are predicted to be several orders of magnitude higher than at the two humid sites - upon initial burial and at 1000 years (after severe erosion). Transfer of wastes containing naturally occurring radionuclides from a humid to an arid environment offers little or no advantage relative to long-term stability of the containment system and has a definite disadvantage in terms of gaseous radioactive releases. 26 references, 3 figures, 4 tables

  18. Evolution of the bHLH genes involved in stomatal development: implications for the expansion of developmental complexity of stomata in land plants.

    Jin-Hua Ran

    Full Text Available Stomata play significant roles in plant evolution. A trio of closely related basic Helix-Loop-Helix (bHLH subgroup Ia genes, SPCH, MUTE and FAMA, mediate sequential steps of stomatal development, and their functions may be conserved in land plants. However, the evolutionary history of the putative SPCH/MUTE/FAMA genes is still greatly controversial, especially the phylogenetic positions of the bHLH Ia members from basal land plants. To better understand the evolutionary pattern and functional diversity of the bHLH genes involved in stomatal development, we made a comprehensive evolutionary analysis of the homologous genes from 54 species representing the major lineages of green plants. The phylogenetic analysis indicated: (1 All bHLH Ia genes from the two basal land plants Physcomitrella and Selaginella were closely related to the FAMA genes of seed plants; and (2 the gymnosperm 'SPCH' genes were sister to a clade comprising the angiosperm SPCH and MUTE genes, while the FAMA genes of gymnosperms and angiosperms had a sister relationship. The revealed phylogenetic relationships are also supported by the distribution of gene structures and previous functional studies. Therefore, we deduce that the function of FAMA might be ancestral in the bHLH Ia subgroup. In addition, the gymnosperm "SPCH" genes may represent an ancestral state and have a dual function of SPCH and MUTE, two genes that could have originated from a duplication event in the common ancestor of angiosperms. Moreover, in angiosperms, SPCHs have experienced more duplications and harbor more copies than MUTEs and FAMAs, which, together with variation of the stomatal development in the entry division, implies that SPCH might have contributed greatly to the diversity of stomatal development. Based on the above, we proposed a model for the correlation between the evolution of stomatal development and the genes involved in this developmental process in land plants.

  19. Life cycle assessment of greenhouse gas emissions, water and land use for concentrated solar power plants with different energy backup systems

    Klein, Sharon J.W.; Rubin, Edward S.

    2013-01-01

    Concentrated solar power (CSP) is unique among intermittent renewable energy options because for the past four years, utility-scale plants have been using an energy storage technology that could allow a CSP plant to operate as a baseload renewable energy generator in the future. No study to-date has directly compared the environmental implications of this technology with more conventional CSP backup energy options. This study compares the life cycle greenhouse gas (GHG) emissions, water consumption, and direct, onsite land use associated with one MW h of electricity production from CSP plants with wet and dry cooling and with three energy backup systems: (1) minimal backup (MB), (2) molten salt thermal energy storage (TES), and (3) a natural gas-fired heat transfer fluid heater (NG). Plants with NG had 4–9 times more life cycle GHG emissions than plants with TES. Plants with TES generally had twice as many life cycle GHG emissions as the MB plants. Dry cooling reduced life cycle water consumption by 71–78% compared to wet cooling. Plants with larger backup capacities had greater life cycle water consumption than plants with smaller backup capacities, and plants with NG had lower direct, onsite life cycle land use than plants with MB or TES. - highlights: • We assess life cycle environmental effects of concentrated solar power (CSP). • We compare CSP with three energy backup technologies and two cooling technologies. • We selected solar field area to minimize energy cost for plants with minimal backup and salt storage. • Life cycle greenhouse gas emissions were 4–9 times lower with thermal energy storage than with fossil fuel backup. • Dry cooling reduced life cycle water use by 71–78% compared to wet cooling

  20. Stability measures in arid ecosystems

    Nosshi, M. I.; Brunsell, N. A.; Koerner, S.

    2015-12-01

    Stability, the capacity of ecosystems to persist in the face of change, has proven its relevance as a fundamental component of ecological theory. Here, we would like to explore meaningful and quantifiable metrics to define stability, with a focus on highly variable arid and semi-arid savanna ecosystems. Recognizing the importance of a characteristic timescale to any definition of stability, our metrics will be focused scales from annual to multi-annual, capturing different aspects of stability. Our three measures of stability, in increasing order of temporal scale, are: (1) Ecosystem resistance, quantified as the degree to which the system maintains its mean state in response to a perturbation (drought), based on inter-annual variability in Normalized Difference Vegetation Index (NDVI). (2) An optimization approach, relevant to arid systems with pulse dynamics, that models vegetation structure and function based on a trade off between the ability to respond to resource availability and avoid stress. (3) Community resilience, measured as species turnover rate (β diversity). Understanding the nature of stability in structurally-diverse arid ecosystems, which are highly variable, yields theoretical insight which has practical implications.

  1. Assessing Rangeland Attributes On Semi-Arid Zone Of North Darfur State Sudan

    Mohamed Almontasir A. M. Mohamed

    2015-08-01

    Full Text Available Abstract The study was conducted over a two years period of 2012 and 2013 at three sites of Alfashir locality Ummarahik 25km north of Alfashir Fashar in eastern part of Alfashir about 5km and Berka 30km west of Alfashir Western Sudan in semi-arid zone. The aim of this study was to assess rangeland attributes. Measurements of plant density vegetation cover range production and carrying capacity were assessed. Results showed that total forage production was low and inadequate to satisfy requirements of livestock for inhabiting the area average range production all over the area was found to be 50.68 kgha and 59.21 kgha for the seasons 2012 and 2013 respectively. The average ground cover was about 34.71 and 42.41 for two seasons. The average plant density for the first season was 27.1 plantm2 while the average plant density for the second season was 29.4 plantm2. The study concluded that unwise utilization and exploitation of the rangelands particularly by man causes range deterioration and serious reduction in range production in both quantity and quality so the study suggested that improvement and rehabilitation such lands rangelands should be done. Further research work is needed to assess rangeland attributes across different ecological zones in North Darfur State.

  2. A cost effective approach to restoration of exploration disturbances in arid Western Australia

    Osborne, J. M. [Curtin Univ. of Technology, School of Environmental Biology, Perth, WA (Australia)

    1999-10-01

    An approach to the remediation of drill line disturbance, including vehicle compaction created by exploration activities, and of drill sump holes that were contaminated by salts and hydrocarbons in the arid lands of Western Australia, is proposed. In the case of drill line trials,it was demonstrated that scarification with seeding with fertilization, and seeding at 6 kg/hectare produced a high level of species richness, and a greater range of life forms than scarification or seeding alone. The higher plant richness was also coupled with significantly higher plant density and cover. In the case of sump holes, it was shown that the application of good quality seed at 15 kg/hectare with fertilizer, applied in late fall on newly prepared surfaces has produced successful plant establishment over disturbed highly saline sumps which contained hydrocarbon derivatives. In terms of cost, drill line rehabilitation at U.S.$ 860 per hectare, and U.S.$ 120 per sump hole were considered to have been highly cost effective. 2 refs., 5 tabs., 4 figs.

  3. A cost effective approach to restoration of exploration disturbances in arid Western Australia

    Osborne, J. M. (Curtin Univ. of Technology, School of Environmental Biology, Perth, WA (Australia))

    1999-01-01

    An approach to the remediation of drill line disturbance, including vehicle compaction created by exploration activities, and of drill sump holes that were contaminated by salts and hydrocarbons in the arid lands of Western Australia, is proposed. In the case of drill line trials,it was demonstrated that scarification with seeding with fertilization, and seeding at 6 kg/hectare produced a high level of species richness, and a greater range of life forms than scarification or seeding alone. The higher plant richness was also coupled with significantly higher plant density and cover. In the case of sump holes, it was shown that the application of good quality seed at 15 kg/hectare with fertilizer, applied in late fall on newly prepared surfaces has produced successful plant establishment over disturbed highly saline sumps which contained hydrocarbon derivatives. In terms of cost, drill line rehabilitation at U.S.$ 860 per hectare, and U.S.$ 120 per sump hole were considered to have been highly cost effective. 2 refs., 5 tabs., 4 figs.

  4. Biomass production on marginal lands - catalogue of bioenergy crops

    Baumgarten, Wibke; Ivanina, Vadym; Hanzhenko, Oleksandr

    2017-04-01

    Marginal lands are the poorest type of land, with various limitations for traditional agriculture. However, they can be used for biomass production for bioenergy based on perennial plants or trees. The main advantage of biomass as an energy source compared to fossil fuels is the positive influence on the global carbon dioxide balance in the atmosphere. During combustion of biofuels, less carbon dioxide is emitted than is absorbed by plants during photosynthesis. Besides, 20 to 30 times less sulphur oxide and 3 to 4 times less ash is formed as compared with coal. Growing bioenergy crops creates additional workplaces in rural areas. Soil and climatic conditions of most European regions are suitable for growing perennial energy crops that are capable of rapid transforming solar energy into energy-intensive biomass. Selcted plants are not demanding for soil fertility, do not require a significant amount of fertilizers and pesticides and can be cultivated, therefore, also on unproductive lands of Europe. They prevent soil erosion, contribute to the preservation and improvement of agroecosystems and provide low-cost biomass. A catalogue of potential bioenergy plants was developed within the EU H2020 project SEEMLA including woody and perennial crops that are allowed to be grown in the territory of the EU and Ukraine. The catalogue lists high-productive woody and perennial crops that are not demanding to the conditions of growing and can guarantee stable high yields of high-energy-capacity biomass on marginal lands of various categories of marginality. Biomass of perennials plants and trees is composed of cellulose, hemicellulose and lignin, which are directly used to produce solid biofuels. Thanks to the well-developed root system of trees and perennial plants, they are better adapted to poor soils and do not require careful maintenance. Therefore, they can be grown on marginal lands. Particular C4 bioenergy crops are well adapted to a lack of moisture and high

  5. Agriculture: Land Use

    Land Use and agriculture. Information about land use restrictions and incentive programs.Agricultural operations sometimes involve activities regulated by laws designed to protect water supplies, threatened or endangered plants and animals, or wetlands.

  6. Disposal options for polluted plants grown on heavy metal contaminated brownfield lands - A review.

    Kovacs, Helga; Szemmelveisz, Katalin

    2017-01-01

    Reducing or preventing damage caused by environmental pollution is a significant goal nowadays. Phytoextraction, as remediation technique is widely used, but during the process, the heavy metal content of the biomass grown on these sites special treatment and disposal techniques are required, for example liquid extraction, direct disposal, composting, and combustion. These processes are discussed in this review in economical and environmental aspects. The following main properties are analyzed: form and harmful element content of remains, utilization of the main and byproducts, affect to the environment during the treatment and disposal. The thermal treatment (combustion, gasification) of contaminated biomass provides a promising alternative disposal option, because the energy production affects the rate of return, and the harmful elements are riched in a small amount of solid remains depending on the ash content of the plant (1-2%). The biomass combustion technology is a wildely used energy production process in residential and industrial scale, but the ordinary biomass firing systems are not suited to burn this type of fuel without environmental risk. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Radioactive waste isolation in arid zones

    Nativ, R.

    1991-01-01

    Arid zones are currently considered ideal sites for the isolation of radioactive and other hazardous wastes. Because arid zones have low precipitation, other hydrological features such as minimal surface water, low recharge rates, small hydraulic gradients, deep water table and lower water quality are also inferred. These premises have proved to be misleading in many circumstances, resulting in groundwater contamination by radionuclides. Case studies indicating surface water damages, occurrence of active recharge, groundwater flow and considerable discharge of potable water in arid and hyper-arid terrains, as well as the possibility of future climatic changes, require careful hydrological assessment of proposed sites in arid areas. (author)

  8. Limited impacts of extensive human land use on dominance, specialization, and biotic homogenization in boreal plant communities.

    Mayor, Stephen J; Boutin, Stan; He, Fangliang; Cahill, James F

    2015-02-13

    Niche theory predicts that human disturbance should influence the assembly of communities, favouring functionally homogeneous communities dominated by few but widespread generalists. The decline and loss of specialists leaves communities with species that are functionally more similar. Evenness of species occupancy declines, such that species become either widespread of rare. These patterns have often been observed, but it is unclear if they are a general result of human disturbance or specific to communities that are rich in species, in complex, spatially heterogeneous environments where the problem has often been investigated. We therefore tested whether human disturbance impacts dominance/evenness of species occupancy in communities, specialism/generalism of species, and functional biotic homogenization in the spatially relatively homogeneous, species poor boreal forest region of Alberta, Canada. We investigated 371 boreal vascular plant communities varying 0 - 100% in proportion of human land use. Rank species occupancy curves revealed high species dominance regardless of disturbance: within any disturbance class a few species occupied nearly every site and most species were found in a low proportion of sites. However, species were more widespread and displayed more even occupancy in intermediately disturbed communities than among communities of either low or high disturbance. We defined specialists and generalists based on turnover in co-occupants and thereby assessed impacts of human disturbance on specialization of species and community homogenization. Generalists were not disproportionately found at higher disturbance sites, and did not occupy more sites. Communities with greater human disturbance were not more functionally homogeneous; they did not harbor communities with more generalists. We unexpectedly did not observe strong linkages between species specialism/generalism and disturbance, nor between community homogenization and disturbance. These

  9. TAS3 miR390-dependent loci in non-vascular land plants: towards a comprehensive reconstruction of the gene evolutionary history

    Sergey Y. Morozov

    2018-04-01

    Full Text Available Trans-acting small interfering RNAs (ta-siRNAs are transcribed from protein non-coding genomic TAS loci and belong to a plant-specific class of endogenous small RNAs. These siRNAs have been found to regulate gene expression in most taxa including seed plants, gymnosperms, ferns and mosses. In this study, bioinformatic and experimental PCR-based approaches were used as tools to analyze TAS3 and TAS6 loci in transcriptomes and genomic DNAs from representatives of evolutionary distant non-vascular plant taxa such as Bryophyta, Marchantiophyta and Anthocerotophyta. We revealed previously undiscovered TAS3 loci in plant classes Sphagnopsida and Anthocerotopsida, as well as TAS6 loci in Bryophyta classes Tetraphidiopsida, Polytrichopsida, Andreaeopsida and Takakiopsida. These data further unveil the evolutionary pathway of the miR390-dependent TAS3 loci in land plants. We also identified charophyte alga sequences coding for SUPPRESSOR OF GENE SILENCING 3 (SGS3, which is required for generation of ta-siRNAs in plants, and hypothesized that the appearance of TAS3-related sequences could take place at a very early step in evolutionary transition from charophyte algae to an earliest common ancestor of land plants.

  10. TAS3 miR390-dependent loci in non-vascular land plants: towards a comprehensive reconstruction of the gene evolutionary history.

    Morozov, Sergey Y; Milyutina, Irina A; Erokhina, Tatiana N; Ozerova, Liudmila V; Troitsky, Alexey V; Solovyev, Andrey G

    2018-01-01

    Trans-acting small interfering RNAs (ta-siRNAs) are transcribed from protein non-coding genomic TAS loci and belong to a plant-specific class of endogenous small RNAs. These siRNAs have been found to regulate gene expression in most taxa including seed plants, gymnosperms, ferns and mosses. In this study, bioinformatic and experimental PCR-based approaches were used as tools to analyze TAS3 and TAS6 loci in transcriptomes and genomic DNAs from representatives of evolutionary distant non-vascular plant taxa such as Bryophyta, Marchantiophyta and Anthocerotophyta. We revealed previously undiscovered TAS3 loci in plant classes Sphagnopsida and Anthocerotopsida, as well as TAS6 loci in Bryophyta classes Tetraphidiopsida, Polytrichopsida, Andreaeopsida and Takakiopsida. These data further unveil the evolutionary pathway of the miR390-dependent TAS3 loci in land plants. We also identified charophyte alga sequences coding for SUPPRESSOR OF GENE SILENCING 3 (SGS3), which is required for generation of ta-siRNAs in plants, and hypothesized that the appearance of TAS3-related sequences could take place at a very early step in evolutionary transition from charophyte algae to an earliest common ancestor of land plants.

  11. Monitoring land degradation with long-term satellite data in South Africa.

    Wessels, Konrad J

    2007-01-01

    Full Text Available Desertification is defined by the United Nations Convention to Combat Desertification (UNCCD) as ‘land degradation in arid, semi-arid and dry sub-humid areas (dry-lands) resulting from various factors, including climatic variations and human...

  12. The impacts of grazing land management on the wind erodibility of the Mulga Lands of western Queensland, Australia

    An estimated 100 Mt of dust is eroded by wind from the Australian land surface each year. Wind erosion may be widespread across the arid and semi-arid rangelands, with impacts on soil nutrients, carbon and ecosystem services, human health, and climate. The susceptibility of landscapes to wind erosio...

  13. Changes in the forest ecosystems in areas impacted by aridization in south-western Romania.

    Pravalie, Remus; Sîrodoev, Igor; Peptenatu, Daniel

    2014-01-06

    In the past few decades, global climate change has accentuated the intensification of aridization in South-Western Romania, with direct and indirect consequences on the quality of forest ecosystems. In addition to qualitative deterioration, the quantitative changes brought about by intensive anthropic deforestation have created the conditions for a decline in the size of forest areas on vast tracts of land. The paper aims to analyze the qualitative and quantitative changes in the forest ecosystems in South-Western Romania, changes due to the synergic context of the global climate changes and the anthropic pressures of the past three decades. In order to capture the evolution of aridization in the study area, specific aridization indexes have been calculated, such as the De Martonne index and the UNEP aridity index. 1990 and 2011 satellite images have been used in order to quantify the qualitative changes. The results obtained indicated that, in the past two decades, the quality of the biomass declined as a result of the increase in the climatic aridity conditions (De Martonne si UNEP aridity index, indicating in the last decades, annual values under 15 mm/°C, and under 0.5 mm/mm, that means that the values situated under these thresholds, describe arid and semi-arid climate conditions). Also, the uncontrolled logging across vast surfaces caused the loss of forest ecosystems by 7% in the overall study area, during the last three decades. The severe effects of aridization meant, first of all, a significant decline in the quality of the ecosystem services supplied by forests. In the absence of viable actions to correct the present situation, the extremely undesirable consequences of an ecological and social nature will arise in the near future.

  14. Radionuclide migration studies at the Savannah River Plant humid shallow land burial site for low-level waste

    Stone, J.A.; Oblath, S.B.; Hawkins, R.H.; Emslie, R.H.; Hoeffner, S.L.; King, C.M.

    1984-01-01

    A program of field, laboratory, and modeling studies for the Savannah River Plant low-level waste burial ground has been conducted for several years. The studies provide generic data on an operating shallow land burial site in a humid region. Recent results from individual studies on subsurface monitoring, lysimeter tests, soil-water chemistry, and transport modeling are reported. Monitoring continues to show little movement of radionuclides except tritium. Long-term lysimeter tests with a variety of defense wastes measure migration under controlled field conditions. One lysimeter was excavated to study radionuclide distribution on the soil column beneath the waste. New soil-water distribution coefficients (K/sub d/) were measured for Co-60, Sr-90, Ru-106, Sb-125, and I-129. Laboratory and field data are integrated by means of the SRL dose-to-man model, to evaluate effects of alternative disposal practices. The model recently has been used to evaluate TRU disposal criteria and to predict migration behavior of tritium, Tc-99, and I-129. 14 references, 2 tables

  15. Herbaceous Legume Encroachment Reduces Grass Productivity and Density in Arid Rangelands.

    Thomas C Wagner

    Full Text Available Worldwide savannas and arid grasslands are mainly used for livestock grazing, providing livelihood to over a billion people. While normally dominated by perennial C4 grasses, these rangelands are increasingly affected by the massive spread of native, mainly woody legumes. The consequences are often a repression of grass cover and productivity, leading to a reduced carrying capacity. While such encroachment by woody plants has been extensively researched, studies on similar processes involving herbaceous species are rare. We studied the impact of a sustained and massive spread of the native herbaceous legume Crotalaria podocarpa in Namibia's escarpment region on the locally dominant fodder grasses Stipagrostis ciliata and Stipagrostis uniplumis. We measured tussock densities, biomass production of individual tussocks and tussock dormancy state of Stipagrostis on ten 10 m x 10 m plots affected and ten similarly-sized plots unaffected by C. podocarpa over eight consecutive years and under different seasonal rainfalls and estimated the potential relative productivity of the land. We found the percentage of active Stipagrostis tussocks and the biomass production of individual tussocks to increase asymptotically with higher seasonal rainfall reaching a maximum around 300 mm while the land's relative productivity under average local rainfall conditions reached only 40% of its potential. Crotalaria podocarpa encroachment had no effect on the proportion of productive grass tussocks, but reduced he productivity of individual Stipagrostis tussocks by a third. This effect of C. podocarpa on grass productivity was immediate and direct and was not compensated for by above-average rainfall. Besides this immediate effect, over time, the density of grass tussocks declined by more than 50% in areas encroached by C. podocarpa further and lastingly reducing the lands carrying capacity. The effects of C. podocarpa on grass productivity hereby resemble those of woody

  16. Plant life form based habitat monitoring in a European landscape framework for early warning of changes in land cover and biodiversity

    Brandt, Jesper; Olsen, Martin; Bloch-Petersen, Margit

    and habitat composition and quality. The focus on essential features of the habitat that can be expressed easily and quantitatively for identification and mapping of small but significant changes at a landscape level has resulted in the reintroduction of Raunkiaers plant life form concept from 1907...... of agricultural land use, general land cover and tree and shrub cover of small biotopes), it has not been difficult to integrate the BioHab framework in the SBMP-monitoring system, thus permitting the monitoring system to deliver an additional important European perspective with only very limited extra resources...

  17. Homogenizing and diversifying effects of intensive agricultural land-use on plant species beta diversity in Central Europe - A call to adapt our conservation measures

    Buhk, Constanze; Alt, Martin; Steinbauer, Manuel

    2016-01-01

    understood due to a lack of systematic case studies: The specific impacts by agriculture in contrast to other land-use creating open habitat are not studied as such landscapes hardly exist in temperate regions. Applying systematic grids, we compared the plant species distribution at the landscape scale....... This was probably the result of species nestedness due to fragmentation. The natural process of increasing dissimilarity with distance (distance-decay) was suppressed by intense agricultural land-use, generalist and long-distance dispersers gained importance, while rare species lost continuity. There are two...

  18. Potential for enhancing nongame bird habitat values on abandoned mine lands of western North Dakota

    Burley, J.B.; Hopkins, R.B.

    1984-01-01

    Throughout western North Dakota the number of unreclaimed surface coal and coal-uranium mines might total over 1100. We examined the potential for enhancing the nongame bird habitat values of unreclaimed mine lands in the arid, western region of North Dakota. Generally, the greatest variety of birds occurred in natural and planted woodlands, while fewer birds occurred in unreclaimed mine lands, grasslands, shrublands and croplands. Deciduous woodland types supported more species of birds than coniferous types. Planted woodlands supported about the same number of bird species as some natural deciduous woodland types and more species than coniferous woods. Unreclaimed mine lands supported more species than grasslands and croplands, and about the same number of species as native shrublands. The highest bird densities were in planted woodlands. Bird diversity varied positively with habitat diversity. The bird fauna of unreclaimed mine lands can be enhanced by creating more diverse habitats. Seventeen guidelines to enhance unreclaimed mine lands for nongame birds are presented. These guidelines can be used in preserving habitats threatened by surface mining and reclaiming previously mined lands

  19. ANALYSING THE EFFECTS OF DIFFERENT LAND COVER TYPES ON LAND SURFACE TEMPERATURE USING SATELLITE DATA

    A. Şekertekin

    2015-12-01

    Full Text Available Monitoring Land Surface Temperature (LST via remote sensing images is one of the most important contributions to climatology. LST is an important parameter governing the energy balance on the Earth and it also helps us to understand the behavior of urban heat islands. There are lots of algorithms to obtain LST by remote sensing techniques. The most commonly used algorithms are split-window algorithm, temperature/emissivity separation method, mono-window algorithm and single channel method. In this research, mono window algorithm was implemented to Landsat 5 TM image acquired on 28.08.2011. Besides, meteorological data such as humidity and temperature are used in the algorithm. Moreover, high resolution Geoeye-1 and Worldview-2 images acquired on 29.08.2011 and 12.07.2013 respectively were used to investigate the relationships between LST and land cover type. As a result of the analyses, area with vegetation cover has approximately 5 ºC lower temperatures than the city center and arid land., LST values change about 10 ºC in the city center because of different surface properties such as reinforced concrete construction, green zones and sandbank. The temperature around some places in thermal power plant region (ÇATES and ZETES Çatalağzı, is about 5 ºC higher than city center. Sandbank and agricultural areas have highest temperature due to the land cover structure.

  20. Analysing the Effects of Different Land Cover Types on Land Surface Temperature Using Satellite Data

    Şekertekin, A.; Kutoglu, Ş. H.; Kaya, S.; Marangoz, A. M.

    2015-12-01

    Monitoring Land Surface Temperature (LST) via remote sensing images is one of the most important contributions to climatology. LST is an important parameter governing the energy balance on the Earth and it also helps us to understand the behavior of urban heat islands. There are lots of algorithms to obtain LST by remote sensing techniques. The most commonly used algorithms are split-window algorithm, temperature/emissivity separation method, mono-window algorithm and single channel method. In this research, mono window algorithm was implemented to Landsat 5 TM image acquired on 28.08.2011. Besides, meteorological data such as humidity and temperature are used in the algorithm. Moreover, high resolution Geoeye-1 and Worldview-2 images acquired on 29.08.2011 and 12.07.2013 respectively were used to investigate the relationships between LST and land cover type. As a result of the analyses, area with vegetation cover has approximately 5 ºC lower temperatures than the city center and arid land., LST values change about 10 ºC in the city center because of different surface properties such as reinforced concrete construction, green zones and sandbank. The temperature around some places in thermal power plant region (ÇATES and ZETES) Çatalağzı, is about 5 ºC higher than city center. Sandbank and agricultural areas have highest temperature due to the land cover structure.

  1. A review of research on ecosystem of arid area using RS-GIS in China

    Han, Hongling

    2007-06-01

    Arid area is classical mountain-oasis-desert ecosystem in North-west China. As the ecosystem has its nature geography character obviously, it has superior to research with remote-sensing and geography information system. The study on arid ecosystem in RS-GIS' way is focused on that the landscape spatial pattern of complex MODS ecosystem, the dynamic development of Land use/land cover, the security of ecological environment of eco-tone and so on. At the same time, the research on the single system is more and more, which has provided more ways and deeper fields of arid area using RS-GIS. Through the use of RS-GIS, desertification, oasis' development, urbanization etc. can be known, which would provide precaution for human-being and suitable ways to adjust the problems.

  2. Small-Scale Farming in Semi-Arid Areas: Livelihood Dynamics between 1997 and 2010 in Laikipia, Kenya

    Ulrich, Anne; Speranza, Chinwe Ifejika; Roden, Paul; Kiteme, Boniface; Wiesmann, Urs; Nusser, Marcus

    2012-01-01

    The rural population of semi-arid lands in Kenya face multiple challenges that result from population growth, poor markets, land use and climatic changes. In particular, subsistence oriented farmers face various risks and opportunities in their attempt to secure their livelihoods. This paper presents an analysis on how livelihood assets and…

  3. Effect of Irradiation of 60CO Gamma Rays on Growth of Garlic (Allium Sativum L) Plants Cv. Lumbu Hijau at Low Land Area

    Ismiyati Sutarto; Kumala Dewi; Arwin; Nurrohma

    2004-01-01

    Garlic originally come from the sub tropical area. In Indonesia, garlic is grown generally in high land area with an altitude between 1000 - 1600 m above sea level. Therefore, the area for growing and producing garlic is limited. Besides, genetic variation of garlic is very narrow since garlic belongs to vegetatively propagated crops. An effort for increasing genetic variation of garlic was done by exposing garlic cloves to gamma rays in order to obtain garlic mutant lines adapted to low land area. Garlic cloves were exposed to different doses of gamma rays 0 (untreated) 2, 4, 6, 8 and 10 Gy at the Centre for Research and Development of Isotope and Radiation Technology. Each dose consisted of 150 garlic cloves. Untreated and irradiated garlic cloves were grown at Bandar Buat Experimental Station (50 m above sea level), Padang, West Sumatera. The experiment was arranged in a randomized block design with three replication. The parameter observed were percentage of grown plants and survival harvested plants, plant height, leaf number, chlorophyll content, number of stomata, plant age, number of cloves per bulbs, fresh, dry weight and diameter of bulbs. The result indicated that the dose of gamma rays 6 Gy is an advantage dose for obtaining well adapted garlic mutant lines in the low land area. (author)

  4. Adaptation to New Climate by an Old Strategy? Modeling Sedentary and Mobile Pastoralism in Semi-Arid Morocco

    Korbinian P. Freier

    2014-07-01

    Full Text Available In a modeling study we examine vulnerability of income from mobile (transhumant pastoralism and sedentary pastoralism to reduced mean annual precipitation (MAP and droughts. The study is based on empirical data of a 3410 km2 research region in southern, semi-arid Morocco. The land use decision model integrates a meta-model of the Environmental Policy Integrated Climate (EPIC simulator to depict perennial and annual forage plant development. It also includes livestock dynamics and forward-looking decision making under uncertain weather. Mobile livestock in the model moves seasonally, sedentary livestock is restricted to pastures around settlements. For a reduction of MAP by 20%, our model shows for different experimental frequencies of droughts a significant decrease of total income from pastoralism by 8%–19% (p < 0.05. Looking separately at the two modes of pastoralism, pronounced income losses of 18%–44% (p < 0.05 show that sedentary pastoralism is much more vulnerable to dryer climate than mobile pastoralism, which is merely affected. Dedicating more pasture area and high quality fodder to mobile pastoralism significantly abates impacts from reduced MAP and droughts on total income by 11% (p < 0.05. Our results indicate that promotion of mobile pastoralism in semi-arid areas is a valuable option to increase resilience against climate change.

  5. Using video to settle land disputes in Lebanon | IDRC - International ...

    2011-02-01

    Feb 1, 2011 ... Before 1950, most Arsaalis were nomadic sheep and goat herders, roaming ... However, quarrying also affects entire stretches of arid mountainside, raising thick ... surrounding dry-land use in the Middle East and North Africa.

  6. Aridity influences the recovery of vegetation and shrubland birds after wildfire.

    Puig-Gironès, Roger; Brotons, Lluís; Pons, Pere

    2017-01-01

    Wildfires play a determining role in the composition and structure of many plant and animal communities. On the other hand, climate change is considered to be a major driver of current and future fire regime changes. Despite increases in drought in many areas of the world, the effects of aridity on post-fire colonization by animals have been rarely addressed. This study aims to analyse how a regional aridity gradient affects post-fire recovery of vegetation, bird species richness and the numbers of four early to middle-successional warbler species associated with the shrub cover. The database contains bird relative abundance and environmental variables from 3072 censuses in 695 transects located in 70 recently burnt areas (1 to 11 years after wildfire) in Catalonia (Spain), which were sampled between 2006 and 2013. Generalized linear mixed models (GLMMs) showed that plant cover was affected by time since fire, aridity and forest management. However, only the highest vegetation height layer (>100 cm) recovered slower in arid areas after fire. Time since fire positively influenced bird species richness and the relative abundance of the four focal species. The post-fire recovery of Melodious (Hippolais polyglotta) and Subalpine warblers (Sylvia cantillans) was hampered by aridity. Although this was not demonstrated for Dartford (S. undata) and Sardinian warblers (S. melanocephala), their occurrence was low in the driest areas during the first three years after fire. Overall, this study suggests that future increases in aridity can affect plant regeneration after fire and slow down the recovery of animal populations that depend on understorey and shrublands. Given the recently highlighted increases in aridity and fire frequency in Mediterranean-climate regions, improved knowledge on how aridity affects ecological succession is especially necessary.

  7. From leaf to basin: evaluating the impacts of introduced plant species on evapotranspiration fluxes from riparian ecosystems in the southwestern U.S

    Hultine, K. R.; Bush, S.; Nagler, P. L.; Morino, K.; Burtch, K.; Dennison, P. E.; Glenn, E. P.; Ehleringer, J.

    2010-12-01

    Global change processes such as climate change and intensive land use pose significant threats to water resources, particularly in arid regions where potential evapotranspiration far exceeds annual rainfall. Potentially compounding these shortages is the progressive expansion of introduced plant species in riparian areas along streams, canals and rivers in geographically arid regions. The question of whether these invasive species have had or will have impacts on water resources is currently under intense debate. We identify a framework for assessing when and where introduced riparian plant species are likely to have the highest potential impact on hydrologic fluxes of arid and semi-arid river systems. We focus on three introduced plant systems that currently dominate southwestern U.S. riparian forests: tamarisk (Tamarix spp.), Russian olive (Eleagnus angustifolia), and Russian knapweed (Acroptilon repens). Our framework focuses on two main criteria: 1) the ecophysiological traits that promote establishment of invasive species across environmental gradients, and 2) an assessment of how hydrologic fluxes are altered by the establishment of introduced species at varying scales. The framework identifies when and where i