WorldWideScience

Sample records for sunglint rivers vegetation

  1. Sunglint Detection for Unmanned and Automated Platforms

    Directory of Open Access Journals (Sweden)

    Oliver Zielinski

    2012-09-01

    Full Text Available We present an empirical quality control protocol for above-water radiometric sampling focussing on identifying sunglint situations. Using hyperspectral radiometers, measurements were taken on an automated and unmanned seaborne platform in northwest European shelf seas. In parallel, a camera system was used to capture sea surface and sky images of the investigated points. The quality control consists of meteorological flags, to mask dusk, dawn, precipitation and low light conditions, utilizing incoming solar irradiance (ES spectra. Using 629 from a total of 3,121 spectral measurements that passed the test conditions of the meteorological flagging, a new sunglint flag was developed. To predict sunglint conspicuous in the simultaneously available sea surface images a sunglint image detection algorithm was developed and implemented. Applying this algorithm, two sets of data, one with (having too much or detectable white pixels or sunglint and one without sunglint (having least visible/detectable white pixel or sunglint, were derived. To identify the most effective sunglint flagging criteria we evaluated the spectral characteristics of these two data sets using water leaving radiance (LW and remote sensing reflectance (RRS. Spectral conditions satisfying ‘mean LW (700–950 nm < 2 mW∙m−2∙nm−1∙Sr−1’ or alternatively ‘minimum RRS (700–950 nm < 0.010 Sr−1’, mask most measurements affected by sunglint, providing an efficient empirical flagging of sunglint in automated quality control.

  2. Bonneville - Hood River Vegetation Management Environmental Assessment

    Energy Technology Data Exchange (ETDEWEB)

    N/A

    1998-08-01

    To maintain the reliability of its electrical system, BPA, in cooperation with the U.S. Forest Service, needs to expand the range of vegetation management options used to clear unwanted vegetation on about 20 miles of BPA transmission line right-of-way between Bonneville Dam and Hood River; Oregon, within the Columbia Gorge National Scenic Area (NSA). We propose to continue controlling undesirable vegetation using a program of Integrated Vegetation Management (IVM) which includes manual, biological and chemical treatment methods. BPA has prepared an Environmental Assessment (EA) (DOE/EA-1257) evaluating the proposed project. Based on the analysis in the EA, BPA has determined that the proposed action is not a major Federal action significantly affecting the quality of the human environment, within the meaning of the National Environmental Policy Act (NEPA) of 1969. Therefore, the preparation of an Environmental Impact Statement (EIS) is not required and BPA is issuing this FONSI.

  3. Emergence of river dynamics through changing vegetation patterns

    Science.gov (United States)

    van Oorschot, Mijke; Kleinhans, Maarten; Middelkoop, Hans; Geerling, Gertjan

    2016-04-01

    Riparian vegetation interacts with morphodynamic processes in rivers to create distinct habitat mosaics supporting a large biodiversity. The aim of our work is to quantitatively investigate the emergent patterns in vegetation and river morphology at the river reach scale by dynamically modelling the processes and their interactions. Here, we coupled an advanced morphodynamic model to a novel dynamic riparian vegetation model to study the interaction between vegetation and morphodynamics. Vegetation colonizes bare substrate within the seed dispersal window, passes several growth stages with different properties and can die through flooding, desiccation, uprooting, scour or burial. We have compared river morphology and vegetation patterns of scenarios without vegetation, with static vegetation that does not grow or die and several dynamic vegetation scenarios with a range of vegetation strategies and eco-engineering properties. Results show that dynamic vegetation has a decreased lateral migration of meander bends and maintains its active meandering behavior as opposed to the scenarios without vegetation and with static vegetation. Also the patterns in vegetation and fluvial morphology and the vegetation age distribution mostly resemble the natural situation when compared to aerial photos of the study area. We find that river dynamics, specifically sinuosity and sediment transport, are very sensitive to vegetation properties that determine vegetation density, settlement location and survival. Future work will include the effects of invasive species, addition of silt and the effect of various river management strategies.

  4. Spatial Vegetation Data for Bluestone National Scenic River Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This data represents a vegetation map for Bluestone National Scenic River. It contains nonoverlapping polygons which represent vegetation classes, aquatic features,...

  5. Spatial Vegetation Data for Upper Delaware Scenic and Recreational River Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — Vegetation map of the Upper Delaware Scenic and Recreational River provides local park-specific names for vegetation types, as well as crosswalks to the National...

  6. Information Content of Aerosol Retrievals in the Sunglint Region

    Science.gov (United States)

    Ottaviani, M.; Knobelspiesse, K.; Cairns, B.; Mishchenko, M.

    2013-01-01

    We exploit quantitative metrics to investigate the information content in retrievals of atmospheric aerosol parameters (with a focus on single-scattering albedo), contained in multi-angle and multi-spectral measurements with sufficient dynamical range in the sunglint region. The simulations are performed for two classes of maritime aerosols with optical and microphysical properties compiled from measurements of the Aerosol Robotic Network. The information content is assessed using the inverse formalism and is compared to that deriving from observations not affected by sunglint. We find that there indeed is additional information in measurements containing sunglint, not just for single-scattering albedo, but also for aerosol optical thickness and the complex refractive index of the fine aerosol size mode, although the amount of additional information varies with aerosol type.

  7. Field Plot Points for New River Gorge National River Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This data set contains point features which represent locations of vegetation sampling plots in the New River Gorge National River. Location coordinates for most...

  8. [Effects of vegetation on river flow: a review].

    Science.gov (United States)

    Xu, Wei-Gang; Zhang, Hua-Yong; Wang, Zhong-Yu; Huang, Wen-Pei

    2013-01-01

    Vegetation is a component of the natural river. To understand the interaction between vegetation and water flow is of scientific and practical significance for the protection of wildlife habitats, the control of water body eutrophication, the ecological restoration of rivers and lakes, and the management of riverways. This paper reviewed the researches about the interaction between vegetation and water flow in riverways, summarized the research progress in the effects of the vegetation on the resistance coefficient and water flow structure, and introduced the applications of numerical simulation in this research field. Based on the previous studies, the effects of river section shape, plant individual form, and vegetation distribution pattern on the flow regime of water flow in vegetation section were analyzed. For further study, the importance of deeply understanding the hydraulics mechanisms of the interaction between vegetation and water flow in terms of the diversity of river morphology, the vegetation variation at different spatiotemporal scales, the water flow distribution in vegetation section, and the three dimensional turbulent simulation was expatiated.

  9. USGS 2015 JSankey Riparian Vegetation and Colorado River

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data include image-based classifications of total vegetation from 1965, 1973, 1984, 1992, 2002, 2004, 2005, and 2009, and characteristics of the river channel...

  10. Roanoke River National Wildlife Refuge Vegetation Classification

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Land cover image for Roanoke River National Wildlife Refuge, in coastal North Carolina. Data was used to map the plant communities on the refuge from the data source...

  11. General classification handbook for floodplain vegetation in large river systems

    Science.gov (United States)

    Dieck, Jennifer J.; Ruhser, Janis; Hoy, Erin E.; Robinson, Larry R.

    2015-01-01

    This handbook describes the General Wetland Vegetation Classification System developed as part of the U.S. Army Corps of Engineers’ Upper Mississippi River Restoration (UMRR) Program, Long Term Resource Monitoring (LTRM) element. The UMRR is a cooperative effort between the U.S. Army Corps of Engineers, U.S. Geological Survey, U.S. Fish and Wildlife Service, and the states of Illinois, Iowa, Minnesota, Missouri, and Wisconsin. The classification system consists of 31 general map classes and has been used to create systemic vegetation data layers throughout the diverse Upper Mississippi River System (UMRS), which includes the commercially navigable reaches of the Mississippi River from Minneapolis, Minnesota, in the north to Cairo, Illinois, in the south, the Illinois River, and navigable portions of the Kaskaskia, Black, St. Croix, and Minnesota Rivers. In addition, this handbook describes the evolution of the General Wetland Vegetation Classification System, discusses the process of creating a vegetation data layer, and describes each of the 31 map classes in detail. The handbook also acts as a pictorial guide to each of the map classes as they may appear in the field, as well as on color-infrared imagery. This version is an update to the original handbook published in 2004.

  12. Modelling of vegetation-driven morphodynamics in braided rivers.

    Science.gov (United States)

    Stecca, Guglielmo; Fedrizzi, Davide; Hicks, Murray; Measures, Richard; Zolezzi, Guido; Bertoldi, Walter; Tal, Michal

    2017-04-01

    River planform results from the complex interaction between flow, sediment transport and vegetation, and can evolve following a change in these controls. The braided planform of New Zealand's Lower Waitaki River, for instance, is endangered by the action of artificially-introduced alien vegetation, which spread across the braidplain following the reduction in magnitude of floods by hydropower dam construction. This vegetation, by encouraging flow concentration into the main channel, would likely promote a shift towards a single-thread morphology if it was not artificially removed within a central fairway. The purpose of this work is to study the evolution of braided rivers such as the Waitaki under different management scenarios through two-dimensional numerical modelling. The construction of a suitable model represents a task in itself, since a modelling framework coupling all the relevant processes is not yet readily available. Our starting point is the physics-based GIAMT2D numerical model, which solves two-dimensional flow and bedload transport in wet/dry domains, and recently modified by the inclusion of a rule-based bank erosion model. We have further developed this model by adding a vegetation module, which accounts in a simplified manner for time-evolving biomass density, adjusting local flow roughness, critical shear stress for sediment transport, and bank erodibility accordingly. Our goal is to use the model to study decadal-scale evolution of a reach on the Waitaki River and predict planform characteristics under different vegetation management scenarios. Here we present the results of a preliminary application of the model to reproduce the morphodynamic evolution of a braided channel in a set of flume experiments that used alfalfa as vegetation. The experiments began with a braided morphology that spontaneoulsy formed at constant flow over a bed of bare uniform sand. The planform transitioned towards single-thread when this discharge was repeatedly

  13. River ecosystem response to prescribed vegetation burning on Blanket Peatland.

    Directory of Open Access Journals (Sweden)

    Lee E Brown

    Full Text Available Catchment-scale land-use change is recognised as a major threat to aquatic biodiversity and ecosystem functioning globally. In the UK uplands rotational vegetation burning is practised widely to boost production of recreational game birds, and while some recent studies have suggested burning can alter river water quality there has been minimal attention paid to effects on aquatic biota. We studied ten rivers across the north of England between March 2010 and October 2011, five of which drained burned catchments and five from unburned catchments. There were significant effects of burning, season and their interaction on river macroinvertebrate communities, with rivers draining burned catchments having significantly lower taxonomic richness and Simpson's diversity. ANOSIM revealed a significant effect of burning on macroinvertebrate community composition, with typically reduced Ephemeroptera abundance and diversity and greater abundance of Chironomidae and Nemouridae. Grazer and collector-gatherer feeding groups were also significantly less abundant in rivers draining burned catchments. These biotic changes were associated with lower pH and higher Si, Mn, Fe and Al in burned systems. Vegetation burning on peatland therefore has effects beyond the terrestrial part of the system where the management intervention is being practiced. Similar responses of river macroinvertebrate communities have been observed in peatlands disturbed by forestry activity across northern Europe. Finally we found river ecosystem changes similar to those observed in studies of wild and prescribed forest fires across North America and South Africa, illustrating some potentially generic effects of fire on aquatic ecosystems.

  14. Riparian Vegetation Encroachment Ratios in rivers below large Dams

    Science.gov (United States)

    Garcia de Jalón, Diego; Martínez-Fernández, Vanesa; González del Tánago, Marta

    2017-04-01

    Large Dams and reservoirs change the natural flow regime and consequently cause many alterations in riparian vegetation dynamics which may be assessed at different spatial and temporal scales. In Mediterranean regions flow regulation is frequently associated with irrigation. Regulated rivers with this purpose very often show reduced discharges during the wet season when the reservoir is being filled and increased discharges during the dry season when irrigation takes place. This type of regulation frequently promotes riparian vegetation growth as soil moisture levels are increased during summer when a natural drought would otherwise limit its growth. Additionally, flow regulation by large dams promotes the aging of late seral riparian vegetation reducing the frequency of flood disturbance and consequently, the potential recruitment of pioneer species. In this work we study the response of woody riparian vegetation to flow regulation by large dams in four rivers from Central Spain: Jarama, Manzanares, Guadalix and Alberche. The aim is to quantify the annual vegetation encroachment ratios and to develop a model to understand the main controlling factors, such as floodplain and channel traits; flow regulation intensity; type of regulation; present vegetation canopy; distance to the dam; and time since dam commissioning. A temporal comparison using aerial photographs from 1956, 1966, 1972, 1991, 2011 and 2014 was done in thirteen river reaches downstream from large dams, to evaluate their morphological evolution.. Floodplain dimensions and channel and riparian vegetation changes were assessed by comparing different pre-dam and post-dam conditions. Recent coloured photographs with 0.5 m spatial resolution and older black-and-white photographs at 1:33 000 spatial scale were supplied by the National Geographic Institute of Spain (www.ign.es) and the Statistical Institute (www.madrid.org/nomecalles/Inicio.icm) from Madrid Community. Similar visual scales were used to cope

  15. Field Plot Points for Upper Delaware Scenic and Recreational River Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — Location of vegetation sampling plots used to collect data for vegetation classification and mapping at Upper Delaware Scenic and Recreational River.

  16. Developing Permanent Vegetable Production Systems for the Red River Delta, Vietnam

    NARCIS (Netherlands)

    Pham Thi Thu Huong, Huong; Everaarts, A.P.; Neeteson, J.J.; Struik, P.C.

    2012-01-01

    The year-round demand for commercially produced vegetables in South-East Asia is growing rapidly because of ongoing population growth and urbanisation. Vegetable production plays an important role in the rural economy of the Red River Delta, the economic centre of northern Vietnam. Field vegetables,

  17. Geomorphic and vegetation changes in a meandering dryland river regulated by a large dam, Sauce Grande River, Argentina

    Science.gov (United States)

    Casado, Ana; Peiry, Jean-Luc; Campo, Alicia M.

    2016-09-01

    This paper investigates post-dam geomorphic and vegetation changes in the Sauce Grande River, a meandering dryland river impounded by a large water-conservation dam. As the dam impounds a river section with scarce influence of tributaries, sources for fresh water and sediment downstream are limited. Changes were inspected based on (i) analysis of historical photographs/imagery spanning pre- (1961) and post-dam (1981, 2004) channel conditions for two river segments located above and below the dam, and (ii) field survey of present channel conditions for a set of eight reference reaches along the river segments. Whilst the unregulated river exhibited active lateral migration with consequent adjustments of the channel shape and size, the river section below the dam was characterized by (i) marked planform stability (93 to 97%), and by (ii) vegetation encroachment leading to alternating yet localized contraction of the channel width (up to 30%). The present river displays a moribund, stable channel where (i) redistribution of sediment along the river course no longer occurs and (ii) channel forms constitute a remnant of a fluvial environment created before closing the dam, under conditions of higher energy. In addition to providing new information on the complex geomorphic response of dryland rivers to impoundment, this paper represents the very first geomorphic assessment of the regulated Sauce Grande and therefore provides an important platform to underpin further research assessing the geomorphic state of this highly regulated dryland river.

  18. Field Plot Points for Bluestone National Scenic River Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This feature class contains point features which represent locations of vegetation sampling plots in Bluestone National Scenic River. Location coordinates for most...

  19. Riparian vegetation classification of the Colorado River Corridor, Grand Canyon, Arizona, 2013—Data

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data are classification maps of total riparian vegetation along the Colorado River in Grand Canyon from Glen Canyon Dam to Pearce Ferry in Arizona. The data...

  20. River flow response to changes in vegetation cover in a South ...

    African Journals Online (AJOL)

    2008-07-23

    Jul 23, 2008 ... may be accomplished using a remotely sensed spectral vegetation index. .... Daily river flow data were obtained from the DWAF using their on-line ..... streamflow of clearing invasive pine and wattle trees from a riparian zone.

  1. Geomorphology and flood-plain vegetation of the Sprague and lower Sycan Rivers, Klamath Basin, Oregon

    Science.gov (United States)

    O'Connor, James E.; McDowell, Patricia F.; Lind, Pollyanna; Rasmussen, Christine G.; Keith, Mackenzie K.

    2015-01-01

    This study provides information on channel and flood-plain processes and historical trends to guide effective restoration and monitoring strategies for the Sprague River Basin, a primary tributary (via the lower Williamson River) of Upper Klamath Lake, Oregon. The study area covered the lower, alluvial segments of the Sprague River system, including the lower parts of the Sycan River, North Fork Sprague River, South Fork Sprague River, and the entire main-stem Sprague River between the confluence of the North Fork Sprague and the South Fork Sprague Rivers and its confluence with the Williamson River at Chiloquin, Oregon. The study included mapping and stratigraphic analysis of flood-plain deposits and flanking features; evaluation of historical records, maps and photographs; mapping and analysis of flood-plain and channel characteristics (including morphologic and vegetation conditions); and a 2006 survey of depositional features left by high flows during the winter and spring of 2005–06.

  2. Braided River Flow and Invasive Vegetation Dynamics in the Southern Alps, New Zealand

    Science.gov (United States)

    Caruso, Brian S.; Edmondson, Laura; Pithie, Callum

    2013-07-01

    In mountain braided rivers, extreme flow variability, floods and high flow pulses are fundamental elements of natural flow regimes and drivers of floodplain processes, understanding of which is essential for management and restoration. This study evaluated flow dynamics and invasive vegetation characteristics and changes in the Ahuriri River, a free-flowing braided, gravel-bed river in the Southern Alps of New Zealand's South Island. Sixty-seven flow metrics based on indicators of hydrologic alteration and environmental flow components (extreme low flows, low flows, high flow pulses, small floods and large floods) were analyzed using a 48-year flow record. Changes in the areal cover of floodplain and invasive vegetation classes and patch characteristics over 20 years (1991-2011) were quantified using five sets of aerial photographs, and the correlation between flow metrics and cover changes were evaluated. The river exhibits considerable hydrologic variability characteristic of mountain braided rivers, with large variation in floods and other flow regime metrics. The flow regime, including flood and high flow pulses, has variable effects on floodplain invasive vegetation, and creates dynamic patch mosaics that demonstrate the concepts of a shifting mosaic steady state and biogeomorphic succession. As much as 25 % of the vegetation cover was removed by the largest flood on record (570 m3/s, ~50-year return period), with preferential removal of lupin and less removal of willow. However, most of the vegetation regenerated and spread relatively quickly after floods. Some flow metrics analyzed were highly correlated with vegetation cover, and key metrics included the peak magnitude of the largest flood, flood frequency, and time since the last flood in the interval between photos. These metrics provided a simple multiple regression model of invasive vegetation cover in the aerial photos evaluated. Our analysis of relationships among flow regimes and invasive vegetation

  3. Remote sensing approach to map riparian vegetation of the Colorado River Ecosystem, Grand Canyon area, Arizona

    Science.gov (United States)

    Nguyen, U.; Glenn, E.; Nagler, P. L.; Sankey, J. B.

    2015-12-01

    Riparian zones in the southwestern U.S. are usually a mosaic of vegetation types at varying states of succession in response to past floods or droughts. Human impacts also affect riparian vegetation patterns. Human- induced changes include introduction of exotic species, diversion of water for human use, channelization of the river to protect property, and other land use changes that can lead to deterioration of the riparian ecosystem. This study explored the use of remote sensing to map an iconic stretch of the Colorado River in the Grand Canyon National Park, Arizona. The pre-dam riparian zone in the Grand Canyon was affected by annual floods from spring run-off from the watersheds of Green River, the Colorado River and the San Juan River. A pixel-based vegetation map of the riparian zone in the Grand Canyon, Arizona, was produced from high-resolution aerial imagery. The map was calibrated and validated with ground survey data. A seven-step image processing and classification procedure was developed based on a suite of vegetation indices and classification subroutines available in ENVI Image Processing and Analysis software. The result was a quantitative species level vegetation map that could be more accurate than the qualitative, polygon-based maps presently used on the Lower Colorado River. The dominant woody species in the Grand Canyon are now saltcedar, arrowweed and mesquite, reflecting stress-tolerant forms adapted to alternated flow regimes associated with the river regulation.

  4. Exploring field vegetation reflectance as an indicator of soil contamination in river floodplains.

    NARCIS (Netherlands)

    Kooistra, L.; Salas, E.A.; Clevers, J.G.; Wehrens, H.R.M.J.; Leuven, R.S.E.W.; Nienhuis, P.H.; Buydens, L.M.C.

    2004-01-01

    This study investigated the relation between vegetation reflectance and elevated concentrations of the metals Ni, Cd, Cu, Zn and Pb in river floodplain soils. High-resolution vegetation reflectance spectra in the visible to near-infrared (400-1350 nm) were obtained using a field radiometer. The rela

  5. Exploring field vegetation reflectance as an indicator of soil contamination in river floodplains

    NARCIS (Netherlands)

    Kooistra, L.; Salas, E.A.L.; Clevers, J.G.P.W.; Wehrens, H.R.M.J.; Leuven, R.S.E.W.; Nienhuis, P.H.; Buydens, L.M.C.

    2004-01-01

    This study investigated the relation between vegetation reflectance and elevated concentrations of the metals Ni, Cd, Cu, Zn and Pb in river floodplain soils. High-resolution vegetation reflectance spectra in the visible to near-infrared (400-1350 nm) were obtained using a field radiometer. The rela

  6. Vegetation NDVI Linked to Temperature and Precipitation in the Upper Catchments of Yellow River

    NARCIS (Netherlands)

    Hao, F.; Zhang, X.; Ouyang, W.; Skidmore, A.K.; Toxopeus, A.G.

    2012-01-01

    Vegetation in the upper catchment of Yellow River is critical for the ecological stability of the whole watershed. The dominant vegetation cover types in this region are grassland and forest, which can strongly influence the eco-environmental status of the whole watershed. The normalized difference

  7. Distinct patterns of interactions between vegetation and river morphology

    NARCIS (Netherlands)

    Van Oorschot, M.; Kleinhans, M.; Middelkoop, H.; Geerling, G.; Buijse, T.; Mosselman, E.

    2014-01-01

    Modelling vegetation and morphodynamics is often one-way traffic that either takes into account the effect of vegetation on morphodynamics or vice versa. The few models that do incorporate an interaction have until now represented vegetation as cylinders causing hydraulic resistance that do not chan

  8. Transfer of cadmium from soil to vegetable in the Pearl River Delta area, South China.

    Science.gov (United States)

    Zhang, Huihua; Chen, Junjian; Zhu, Li; Yang, Guoyi; Li, Dingqiang

    2014-01-01

    The purpose of this study was to investigate the regional Cadmium (Cd) concentration levels in soils and in leaf vegetables across the Pearl River Delta (PRD) area; and reveal the transfer characteristics of Cadmium (Cd) from soils to leaf vegetable species on a regional scale. 170 paired vegetables and corresponding surface soil samples in the study area were collected for calculating the transfer factors of Cadmium (Cd) from soils to vegetables. This investigation revealed that in the study area Cd concentration in soils was lower (mean value 0.158 mg kg(-1)) compared with other countries or regions. The Cd-contaminated areas are mainly located in west areas of the Pearl River Delta. Cd concentrations in all vegetables were lower than the national standard of Safe vegetables (0.2 mg kg(-1)). 88% of vegetable samples met the standard of No-Polluted vegetables (0.05 mg kg(-1)). The Cd concentration in vegetables was mainly influenced by the interactions of total Cd concentration in soils, soil pH and vegetable species. The fit lines of soil-to-plant transfer factors and total Cd concentration in soils for various vegetable species were best described by the exponential equation (y = ax(b)), and these fit lines can be divided into two parts, including the sharply decrease part with a large error range, and the slowly decrease part with a low error range, according to the gradual increasing of total Cd concentrations in soils.

  9. Transfer of cadmium from soil to vegetable in the Pearl River Delta area, South China.

    Directory of Open Access Journals (Sweden)

    Huihua Zhang

    Full Text Available The purpose of this study was to investigate the regional Cadmium (Cd concentration levels in soils and in leaf vegetables across the Pearl River Delta (PRD area; and reveal the transfer characteristics of Cadmium (Cd from soils to leaf vegetable species on a regional scale. 170 paired vegetables and corresponding surface soil samples in the study area were collected for calculating the transfer factors of Cadmium (Cd from soils to vegetables. This investigation revealed that in the study area Cd concentration in soils was lower (mean value 0.158 mg kg(-1 compared with other countries or regions. The Cd-contaminated areas are mainly located in west areas of the Pearl River Delta. Cd concentrations in all vegetables were lower than the national standard of Safe vegetables (0.2 mg kg(-1. 88% of vegetable samples met the standard of No-Polluted vegetables (0.05 mg kg(-1. The Cd concentration in vegetables was mainly influenced by the interactions of total Cd concentration in soils, soil pH and vegetable species. The fit lines of soil-to-plant transfer factors and total Cd concentration in soils for various vegetable species were best described by the exponential equation (y = ax(b, and these fit lines can be divided into two parts, including the sharply decrease part with a large error range, and the slowly decrease part with a low error range, according to the gradual increasing of total Cd concentrations in soils.

  10. Refinement of the critical angle calculation for the contrast reversal of oil slicks under sunglint

    Science.gov (United States)

    Lu, Yingcheng; Sun, Shaojie; Zhang, Minwei; Murch, Brock; Hu, Chuanmin

    2016-01-01

    It has long been observed that oil slicks under sunglint can reverse their optical contrast against nearby oil-free seawater. Such a phenomenon has been described through both empirical statistical analysis of the sunglint strength and modeled theoretically using a critical angle concept. The critical angle, in this model, is the angle at which the image pixels show no or negligible contrast between oiled and nonoiled seawater. Pixels away from this critical angle show either positive or negative contrast from the oil-free pixels. Although this concept has been fully demonstrated in the published literature, its calculation needs to be further refined to take into account: (1) the different refractive indices of oil slicks (from natural seeps) and seawater and (2) atmospheric effects in the sensor-measured radiance. Using measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) over oil films in the Gulf of Mexico, we show improvement in the modeled and MODIS-derived reflectance over oil slicks originated from natural seeps after incorporating these two factors in the model. Specifically, agreement between modeled and measured sunglint reflectance is found for both negative and positive-contrasting oil slicks. These results indicate that surface roughness and reflectance from oil films can be estimated given any solar/viewing geometry and surface wind. Further, this model might be used to correct the sunglint effect on thick oil under similar illumination conditions. Once proven possible, it may allow existing laboratory-based models, which estimate oil thickness after such corrections, to be applied to remote sensing imagery.

  11. Spatiotemporal changes of vegetation and their responses to temperature and precipitation in upper Shiyang river basin

    Science.gov (United States)

    Tang, Zhiguang; Ma, Jinhui; Peng, Huanhua; Wang, Shuhan; Wei, Junfeng

    2017-09-01

    The Shiyang river basin is a typical arid inland river basin in northwestern China, where significant climate change and ecological environment deterioration has been observed over the past several decades. The vegetation in Shiyang river basin is mostly concentrated in its upstream, and plays an important role in ecological environment of this watershed. However, how the regional vegetation responds to such climatic change is poorly understood. To address this question, the spatiotemporal changes of vegetation growth in upper Shiyang river basin together with their responses to climate changes were investigated using SPOT VEGETATION Normalized Difference Vegetation Index (NDVI) and climate datasets from 1999 to 2013. Results reveal that about 81.3% of the study area shows an increasing trend in NDVI. The average NDVI of the study area increases at rates of 7.75% for the growing season (March-November), 11.75% for spring (March-May), 9.62% for summer (June-August), and 5.98% for autumn (September-November) over the study period. The increase of NDVI in spring and autumn suggests the growing season of the vegetation in this study area has been prolonged. The effects of climate changes on vegetation growth vary with the types of vegetation and seasons, which shows a large spatial and temporal heterogeneity. As compared with temperature, precipitation is the dominant climatic factor affecting the interannual variations of vegetation. If the temperature and precipitation continue to increase in the study area, the sensitivity of vegetation growth to temperature and precipitation may decline.

  12. PermVeg: A model to design crop sequences for permanent vegetable production systems in the Red River Delta, Vietnam

    NARCIS (Netherlands)

    Pham Thi Thu Huong, Huong; Everaarts, A.P.; Berg, van den W.; Neeteson, J.J.; Struik, P.C.

    2014-01-01

    The constraints in current vegetable production systems in the Red River Delta, Vietnam, in which vegetables are rotated with flooded rice, called for the design of alternative systems of permanent vegetable production. The practical model, PermVeg, was developed to generate vegetable crop sequences

  13. Meandering rivers - feedbacks between channel dynamics, floodplain and vegetation

    NARCIS (Netherlands)

    van Dijk, W.M.

    2013-01-01

    Rivers have distinctive channel patterns such as multi-channel braiding and single-channel meandering. Why these different river patterns emerge is only qualitatively understood. Yet, we have not been able to retain dynamic meandering in laboratory experiments. The main objective of this thesis was

  14. Connectivity processes and riparian vegetation of the upper Paraná River, Brazil

    Science.gov (United States)

    Stevaux, José C.; Corradini, Fabrício A.; Aquino, Samia

    2013-10-01

    In fluvial systems, the relationship between a dominant variable (e.g. flood pulse) and its dependent ones (e.g. riparian vegetation) is called connectivity. This paper analyzes the connectivity elements and processes controlling riparian vegetation for a reach of the upper Paraná River (Brazil) and estimates the future changes in channel-vegetation relationship as a consequence of the managing of a large dam. The studied reach is situated 30 km downstream from the Porto Primavera Dam (construction finished in 1999). Through aerial photography (1:25,000, 1996), RGB-CBERS satellite imagery and a previous field botany survey it was possible to elaborate a map with the five major morpho-vegetation units: 1) Tree-dominated natural levee, 2) Shrubby upper floodplain, 3) Shrub-herbaceous mid floodplain, 4) Grass-herbaceous lower floodplain and 5) Shrub-herbaceous flood runoff channel units. By use of a detailed topographic survey and statistical tools each morpho-vegetation type was analyzed according to its connectivity parameters (frequency, recurrence, permanence, seasonality, potamophase, limnophase and FCQ index) in the pre- and post-dam closure periods of the historical series. Data showed that most of the morpho-vegetation units were predicted to present changes in connectivity parameters values after dam closing and the new regime could affect, in different intensity, the river ecology and particularly the riparian vegetation. The methods used in this study can be useful for dam impact studies in other South American tropical rivers.

  15. Mechanisms of vegetation removal by floods on bars of a heavily managed gravel bed river (The Isere River, France)

    Science.gov (United States)

    Jourdain, Camille; Belleudy, Philippe; Tal, Michal; Malavoi, Jean-René

    2016-04-01

    In natural alpine gravel bed rivers, floods and their associated bedload transport maintain channels active and free of mature woody vegetation. In managed rivers, where flood regime and sediment supply have been modified by hydroelectric infrastructures and sediment mining, river beds tend to stabilize. As a result, in the recent past, mature vegetation has established on gravel bars of many gravel bed rivers worldwide. This established vegetation increases the risk of flooding by decreasing flow velocity and increasing water levels. In addition, the associated reduction in availability of pioneer habitats characteristic of these environments typically degrades biodiversity. Managing hydrology in a way that would limit vegetation establishment on bars presents an interesting management option. In this context, our study aims at understanding the impacts of floods of varying magnitude on vegetation removal, and identifying and quantifying the underlying mechanisms. Our study site is the Isère River, a heavily managed gravel bed river flowing in the western part of the French Alps. We studied the impact of floods on sediment transport and vegetation survival at the bar scale through field monitoring from 2014 to 2015, focusing on young salicaceous vegetation (chains, and topographic surveys. Hourly water discharge was obtained from the national gauging network. The hydraulics of monitored floods was characterized using a combination of field measurements and 2D hydraulic modeling: water levels were measured with pressure sensors and Large Scale Particle Velocimetry was used to measure flow velocities. These data were used to calibrate 2D hydrodynamic model using TELEMAC2D. At the reach scale, removal of mature vegetation was assed using a series of historical aerial photographs between 2001 and 2015. Our monitoring period covered a series of floods with recurrence intervals of 2 to 4 times per year, as well as one large flood with a 10 year return period. Only the

  16. Predicting the impact of water demand and river flow regulation over riparian vegetation through mathematical modeling

    Science.gov (United States)

    Garcia-Arias, A.; Pons, C.; Frances, F.

    2013-12-01

    The vegetation of the riversides is a main part of the complex riparian ecosystems and has an important role maintaining the fluvial ecosystems. Biotic and abiotic interactions between the river and the riverbank are essential for the subsistence and the development of both ecosystems. In semi-arid Mediterranean areas, the riparian vegetation growth and distribution is especially controlled by the water accessibility, determining the limit between the lush riparian bands and the sparse upland. Human intervention can alter the river hydrology determining the riparian vegetation wellbeing and its distribution and, in consequence, affecting both riparian and fluvial ecosystems. Predictive models are necessary decision support tools for adequate river management and restoration initiatives. In this context, the RibAV model is useful to predict the impact of water demand and river flow regulation on the riparian vegetation. RibAV is able to reproduce the vegetation performance on the riverside allowing the scenarios analysis in terms of vegetation distribution and wellbeing. In this research several flow regulation and water demand scenarios are proposed and the impacts over three plant functional types (PFTs) are analyzed. The PFTs group the herbaceous riparian plants, the woody riparian plants and the terrestrial vegetation. The study site is the Terde reach at the Mijares River, a 539m length reach located in a semi-arid Mediterranean area in Spain. The scenarios represent river flow alterations required to attend different human demands. These demands encompass different seasonality, magnitude and location. The seasonality is represented as hydroelectric (constant all over the year), urban (increased during the summer period) and agricultural demands (monthly seasonality). The magnitude is varied considering the 20%, the 40% and the 80% of the mean daily flow. Two locations are considered, upstream or downstream the study site. To attend the demands located

  17. NVC Vegetation Classification for Assabet River National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — James W. Sewall Company used its standard photointerpretation and ortho-mapping workflow and was assisted by NatureServe in crosswalking to NVC vegetation and...

  18. NVC Vegetation Classification for Parker River National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — James W. Sewall Company used its standard photointerpretation and ortho-mapping workflow and was assisted by NatureServe in crosswalking to NVC vegetation and...

  19. Roanoke River National Wildlife Refuge National Vegetation Classification

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The United States Fish and Wildlife Service (USFWS) contracted with Phillip A. Townsend to determine and map the plant communities within the Roanoke River National...

  20. Vegetation Phenology and Intensity as a Function of Climate and River Flows for an Ephemeral Desert River, 2000 to 2010, Using MODIS Satellite Data

    Science.gov (United States)

    Nguyen, U.; Nagler, P. L.; Glenn, E. P.; Van Riper, C., III

    2011-12-01

    The San Pedro river, located along Sonoran and Chihuahuan desert, is one of the most biologically diverse ecosystems in the Rocky mountains of the Southwestern United States. Vegetation dynamics related to seasonal changes may affect the life and migration of many wildlife species. Furthermore, vegetation density is related to surface flows in the river and depth to groundwater, which vary year to year. The MODIS Vegetation Index products (EVI and NDVI) were used to monitor vegetation dynamics during 10 years (2000-2010) to examine the impact of climatic conditions (such as temperature from LST, precipitation from PRISM and rive flows from gaga data) on the onset of greenness, senescence, and maximum vegetation density. The phenology profiles from time series data and relationships between vegetation index and temperature not only show seasonal changes but also respond to moisture stress on vegetation in the riparian areas of the San Pedro River.

  1. Controls on sinuosity in the sparsely vegetated Fossálar River, southern Iceland

    Science.gov (United States)

    Ielpi, Alessandro

    2017-06-01

    Vegetation exerts strong controls on fluvial sinuosity, providing bank stability and buffering surface runoff. These controls are manifest in densely vegetated landscapes, whereas sparsely vegetated fluvial systems have been so far overlooked. This study integrates remote sensing and gauging records of the meandering to wandering Fossálar River, a relatively steep-sloped ( 0.05), suggesting that relationships between the two are mediated by intervening variables and uncertain lag times. By comparison, discharge regime and fluvial planform show direct correlation over monthly to yearly time scales, with stable discharge stages accompanying the accretion of meander bends and peak floods related to destructive point-bar reworking. Rapid planform change is aided by the unconsolidated nature of unrooted alluvial banks, with recorded rates of lateral channel-belt migration averaging 18 m/yr. Valley confinement and channel mobility also control the geometry and evolution of individual point bars, with the highest degree of spatial geomorphic variability recorded in low-gradient stretches where lateral migration is unimpeded. Point bars in the Fossálar River display morphometric values comparable to those of other sparsely vegetated rivers, suggesting shared scalar properties. This conjecture prompts the need for more sophisticated integrations between remote sensing and gauging records on modern rivers lacking widespread plant life. While a large volume of experimental and field-based work maintains that thick vegetation has a critical role in limiting braiding, thus favouring sinuosity, this study demonstrates the stronger controls of discharge regime and alluvial morphology on sparsely vegetated sinuous rivers.

  2. Occurrence of a bimodal behavior in riparian vegetation dynamics driven by river flow variability

    Science.gov (United States)

    Camporeale, C.; Ridolfi, L.

    2006-12-01

    The riparian zone is a fluvial ecotone which exhibits very interesting interaction between hydraulics and ecology, with several important implications in the environmental management. Even though random variability is a key characteristic of the river hydrology, which plays a crucial role in the evolution of riparian vegetation, the impact of stochastic hydrologic fluctuations on the dynamics of riparian vegetation ecosystems remains for most part poorly understood. Here we propose a new approach to study the distribution of phreatophyte riparian vegetation, using a stochastic process to model the random forcing exerted by river flow on the dynamics of the overall biomass of vegetation. Growth and decrease of vegetation are modelled through a logistic and an exponential functions, respectively, which switch in a random way, depending on the flooding conditions. The time series of the river flow (described by the pdf and autocorrelation function), determines the corresponding time series of the water levels which in turn drives the statistical characteristics of the switching. In the logistic model, the carrying capacity is taken dependent on the water table depth through a quadratic optimum function with species-dependent parameters. A dimensional analysis shows that the fundamental factors are the autocorrelation function of the flow, the coefficient of variation, the ratio between growth and decrease rate of vegetation and the optimum water table depth. The switching dynamics is shown to be described by a single stochastic differential equation driven by dichotomic noise that is analytically solved herein. The main outcome is the pdf of the vegetation biomass at the steady state which allows the stability of the models and the central moments to be investigated. Bimodality of the solution and peculiar behaviors (e.g., noise-induced stability) are discussed, depending on the river geometry and the hydrological characteristics. The obtained analytical expressions

  3. A predictive model for floating leaf vegetation in the St. Louis River Estuary

    Science.gov (United States)

    In July 2014, USEPA staff was asked by MPCA to develop a predictive model for floating leaf vegetation (FLV) in the St. Louis River Estuary (SLRE). The existing model (Host et al. 2012) greatly overpredicts FLV in St. Louis Bay probably because it was based on a limited number of...

  4. ALIEN SPECIES IMPORTANTANCE IN NATIVE VEGETATION ALONG WADEABLE STREAMS, JOHN DAY RIVER BASIN, OREGON, USA

    Science.gov (United States)

    We evaluated the importance of alien species in existing vegetation along wadeable streams of a large, topographically diverse river basin in eastern Oregon, USA; sampling 165 plots (30 × 30 m) across 29 randomly selected 1-km stream reaches. Plots represented eight streamside co...

  5. Floodplain vegetation of the River Murray in 1987–1988 : an important pre-drought benchmark for subsequent studies

    OpenAIRE

    Smith, Peter; Smith, Judy

    2014-01-01

    As part of a wider study of floodplain vegetation along the River Murray, we carried out a field survey in 1987–1988 involving collection of floristic and vegetation condition data from 335 sample plots (each 400 m2 in area), between Hume Dam and Lake Alexandrina (including the Edward-Wakool anabranch system). The floodplain vegetation is dominated by just two tree species, River Red Gum (Eucalyptus camaldulensis) and Black Box (Eucalyptus largiflorens), but the composition of the understorey...

  6. Color Infrared Orthorectified Photomosaic Leaf-off for New River Gorge National River Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — Orthorectified color infrared ERDAS IMAGINE and MrSID image of New River Gorge National River (final_neri_mosaic.img). Produced from 471 color infrared photos taken...

  7. Maximum entropy production, carbon assimilation, and the spatial organization of vegetation in river basins.

    Science.gov (United States)

    del Jesus, Manuel; Foti, Romano; Rinaldo, Andrea; Rodriguez-Iturbe, Ignacio

    2012-12-18

    The spatial organization of functional vegetation types in river basins is a major determinant of their runoff production, biodiversity, and ecosystem services. The optimization of different objective functions has been suggested to control the adaptive behavior of plants and ecosystems, often without a compelling justification. Maximum entropy production (MEP), rooted in thermodynamics principles, provides a tool to justify the choice of the objective function controlling vegetation organization. The application of MEP at the ecosystem scale results in maximum productivity (i.e., maximum canopy photosynthesis) as the thermodynamic limit toward which the organization of vegetation appears to evolve. Maximum productivity, which incorporates complex hydrologic feedbacks, allows us to reproduce the spatial macroscopic organization of functional types of vegetation in a thoroughly monitored river basin, without the need for a reductionist description of the underlying microscopic dynamics. The methodology incorporates the stochastic characteristics of precipitation and the associated soil moisture on a spatially disaggregated framework. Our results suggest that the spatial organization of functional vegetation types in river basins naturally evolves toward configurations corresponding to dynamically accessible local maxima of the maximum productivity of the ecosystem.

  8. The influence of flood frequency, riparian vegetation and threshold on long-term river transport capacity

    Science.gov (United States)

    Croissant, Thomas; Lague, Dimitri; Davy, Philippe

    2016-04-01

    Climate fluctuations at geological timescales control the capacity of rivers to transport sediment with consequences on geochemical cycles, sedimentary basins dynamics and sedimentation/tectonics interactions. While the impact of differential friction generated by riparian vegetation has been studied for individual flood events, its impact on the long-term sediment transport capacity of rivers, modulated by the frequency of floods remains unknown. Here, we investigate this effect on a simplified river-floodplain configuration obeying observed hydraulic scaling laws. We numerically integrate the full-frequency magnitude distribution of discharge events and its impact on the transport capacity of bedload and suspended material for various level of vegetation-linked differential friction. We demonstrate that riparian vegetation by acting as a virtual confinement of the flow i) increases significantly the instantaneous transport capacity of the river independently of the transport mode and ii) increases the long term bedload transport rates as a function of discharge variability. Our results expose the dominance of flood frequency rather than riparian vegetation on the long term sediment transport capacity. Therefore, flood frequency has to be considered when evaluating long-term bedload transport capacity while floodplain vegetation is important only in high discharge variability regimes. By comparing the transport capacity of unconfined alluvial rivers and confined bedrock gorges, we demonstrate that the latter always presents the highest long term transport capacity at equivalent width and slope. The loss of confinement at the transition between bedrock and alluvial river must be compensated by a widening or a steepening of the alluvial channel to avoid infinite storage. Because steepening is never observed in natural system, we compute the alluvial widening factor value that varies between 3 to 11 times the width of the bedrock channel depending on riparian

  9. Species composition of the vegetation along the Sherichhu River, lower montane area of Eastern Bhutan

    Directory of Open Access Journals (Sweden)

    Tenzin Jamtsho

    2017-06-01

    Full Text Available An investigation of the riparian vegetation along the Sherichhu River, lower montane area of Eastern Bhutan was conducted from April to December 2015 to explore the plant communities in terms of species composition. A total number of 18 plots were placed within the remnant patches of the vegetation on either side of the river. In total, 172 species of vascular plant has been recorded. The cluster analysis suggested four types of plant communities in the study area viz., the MallotusDesmodium-Rhus shrubland and the Syzygium venosum woodland communities, which are located in V-shaped valleys and the Albizia-Flueggea woodland and Quercus glauca woodland communities located in U-shaped valleys. In broad-spectrum, the topographic features and environmental variables i.e. litter accumulation and flooding condition might also have some impact on the species composition of the plant communities of this vegetation.

  10. Riparian vegetation and its water use during 1995 along the Mojave River, Southern California

    Science.gov (United States)

    Lines, Gregory C.; Bilhorn, Thomas W.

    1996-01-01

    The extent and areal density of riparian vegetation, including both phreatophytes and hydrophytes, were mapped along the 100-mile main stem of the Mojave River during 1995. Mapping was aided by vertical false-color infrared and low-level oblique photographs. However, positive identification of plant species and plant physiological stress required field examination. The consumptive use of ground water and surface water by different areal densities of riparian plant communities along the main stem of the Mojave River was estimated using water-use data from a select group of studies in the southwestern United States. In the Alto subarea of the Mojave basin management area, consumptive water use during 1995 by riparian vegetation was estimated to be about 5,000 acre-feet upstream from the Lower Narrows and about 6,000 acre-feet downstream in the transition zone. In the Centro and Baja subareas, consumptive water use was estimated to be about 3,000 acre-feet and 2,000 acre-feet, respectively, during 1995. Consumptive water use by riparian vegetation in the Afton area, downstream from the Baja subarea, was estimated to be about 600 acre-feet during 1995. Consumptive water use by riparian vegetation during 1995 is considered representative of "normal" hydrologic conditions along the Mojave River. Barring major changes in the areal extent and density of riparian vegetation, the 1995 consumptive-use estimates should be fairly representative of riparian vegetation water use during most years. Annual consumptive use, however, could vary from the 1995 estimates as much as plus or minus 50 percent because of extreme hydrologic conditions (periods of high water table following extraordinarily large runoff in the Mojave River or periods of extended drought).

  11. Invasive riparian vegetation response to flow regimes and flood pulses in a braided river floodplain.

    Science.gov (United States)

    Caruso, Brian S; Pithie, Callum; Edmondson, Laura

    2013-08-15

    This study evaluated flow regimes and flood pulse characteristics, and their influences on invasive riparian vegetation, in a free-flowing braided river in the Southern Alps, South Island, New Zealand. A 46-year gauged flow record was used to evaluate 67 flow metrics for the Ahuriri River, and five sets of colour aerial photographs over 20 years (1991-2011) were analysed to quantify temporal and spatial changes in vegetation (crack willow, Russell lupin, and grassland). The correlation between flow metrics and vegetation class cover for each aerial photo interval was analysed, and multiple regression models were developed. Significant changes in different invasive vegetation classes were found, including cover, number and sizes of patches, and distances from patches to primary channels. In addition to infrequent large floods, specific characteristics of small floods, high flows, low/baseflows, and extreme low flows had influences on different vegetation classes. Key metrics that appear to drive changes in cover and provide a useful multiple regression model include the largest flood peak, frequency of floods, and the time since the last flood for each air photo interval. Up to 25% of invasive vegetation cover was removed and bare substrate increased after the largest flood on record (approximately 50-year flood), and the amount of vegetation cover is highly variable over time and space. Within approximately six years, however, the proportion of vegetation recovered to pre-flood levels. The study reach appears to demonstrate the "shifting-mosaic steady state" conceptual model of riverine floodplains, where the total proportion of substrate, vegetation and water remain relatively constant over long time periods.

  12. Application of Remote Sensing Detection and GIS in Analysis of Vegetation Pattern Dynamics in the Yellow River Delta

    Institute of Scientific and Technical Information of China (English)

    Song Chuangye; Liu Gaohuan

    2008-01-01

    Regional vegetation pattern dynamics has a great im-pact on ecosystem and climate change. Remote sensing data and geographical information system (GIS) analysis were widely used in the detection of vegetation pattern dynamics. In this study, the Yellow River Delta was selected as the study area. By using 1986, 1993, 1996, 1999 and 2005 remote sensing data as basic informa-tion resource, with the support of GIS, a wetland vegetation spa-tial information dataset was built up. Through selecting the land-scape metrics such as class area (CA), class percent of landscape (PL), number of patch (NP), largest patch index (LPI) and mean patch size (MPS) etc., the dynamics of vegetation pattern was analyzed. The result showed that the change of vegetation pattern is significant from 1986 to 2005. From 1986-1999, the area of the vegetation, the percent of vegetation, LPI and MPS decreased, the NP increased, the vegetation pattern tends to be fragmental. The decrease in vegetation area may well be explained by the fact of the nature environment evolution (Climate change and decrease in Yellow River runoff) and the increase in the population in the Yellow River Delta. However, from 1999-2005, the area of the vegetation, the percent of vegetation, LPI and MPS increased, while the NP decreased. This trend of restoration may be due to the implementation of water resources regulation for the Yellow River Delta since 1999.

  13. Vegetation Carbon Storage, Spatial Patterns and Response to Altitude in Lancang River Basin, Southwest China

    Directory of Open Access Journals (Sweden)

    Long Chen

    2016-01-01

    Full Text Available Vegetation plays a very important role of carbon (C sinks in the global C cycle. With its complex terrain and diverse vegetation types, the Lancang River Basin (LRB of southwest China has huge C storage capacity. Therefore, understanding the spatial variations and controlling mechanisms of vegetation C storage is important to understand the regional C cycle. In this study, data from a forest inventory and field plots were used to estimate and map vegetation C storage distribution in the LRB, to qualify the quantitative relationships between vegetation C density and altitude at sublot and township scale, and a linear model or polynomial model was used to identify the relationship between C density and altitude at two spatial scales and two statistical scales. The results showed that a total of 300.32 Tg C was stored in the LRB, an important C sink in China. The majority of C storage was contributed by forests, notably oaks. The vegetation C storage exhibited nonlinear variation with latitudinal gradients. Altitude had tremendous influences on spatial patterns of vegetation C storage of three geomorphological types in the LRB. C storage decreased with increasing altitude at both town and sublot scales in the flat river valley (FRV region and the mid-low mountains gorge (MMG region, and first increased then decreased in the alpine gorge (AG region. This revealed that, in southwest China, altitude changes the latitudinal patterns of vegetation C storage; especially in the AG area, C density in the mid-altitude (3100 m area was higher than that of adjacent areas.

  14. Measuring bed shear stress along vegetated river beds using FST-hemispheres.

    Science.gov (United States)

    Bockelmann-Evans, B N; Davies, R; Falconer, R A

    2008-09-01

    The measurement of the bed shear stress along vegetated river beds is essential for accurately predicting the water level, velocity and solute and sediment transport fluxes in computational hydroenvironmental models. Details are given herein of an experimental and theoretical study to determine the bed boundary shear stress along vegetated river beds introducing a novel field measuring method, namely the FliessWasserStammtisch (FST)-hemispheres. Although investigations have been conducted previously for sedimentary channels using the FST-hemispheres, this preliminary study is thought to be the first time that such hemispheres have been used to investigate the bed shear stresses in vegetated channels. FST-hemispheres were first developed by Statzner and Müller [1989. Standard hemispheres as indicators of flow characteristics in lotic benthos research. Freshwater Biology 21, 445-459] to act as an integrated indicator of the gross hydrodynamic stresses present near the bed. Test and validation data were found to be at least of the same order of magnitude for the stresses predicted from literature for sedimentary channels, with this study establishing the commencement of a database of calibrated FST-hemisphere laboratory data for vegetated channel beds. In a series of experiments, depths ranging from 0.1 to 0.28 m were considered, equating directly to comparable conditions in small rivers or streams. The results of this study provide a basis for enabling the FST-hemispheres to be used to evaluate the boundary shear stress for a wider range of applications in the future, including vegetated river beds.

  15. Impact of climate change on vegetation dynamics in a West African river basin

    Science.gov (United States)

    Sawada, Y.; Koike, T.

    2012-12-01

    Future changes in terrestrial biomass distribution under climate change will have a tremendous impact on water availability and land productivity in arid and semi-arid regions. Assessment of future change of biomass distribution in the regional or the river basin scale is strongly needed. An eco-hydrological model that fully couples a dynamic vegetation model (DVM) with a distributed biosphere hydrological model is applied to multi-model assessment of climate change impact on vegetation dynamics in a West African river basin. In addition, a distributed and auto optimization system of parameters in DVM is developed to make it possible to model a diversity of phonologies of plants by using different parameters in the different model grids. The simple carbon cycle modeling in a distributed hydrological model shows reliable accuracy in simulating the seasonal cycle of vegetation on the river basin scale. Model outputs indicate that generally, an extension of dry season duration and surface air temperature rising caused by climate change may cause a dieback of vegetation in West Africa. However, we get different seasonal and spatial changes of leaf area index and different mechanisms of the degradation when we used different general circulation models' outputs as meteorological forcing of the eco-hydrological model. Therefore, multi-model analysis like this study is important to deliver meaningful information to the society because we can discuss the uncertainties of our prediction by this methodology. This study makes it possible to discuss the impact of future change of terrestrial biomass on climate and water resources in the regional or the river basin scale although we need further sophistications of the system. Performance of the eco-hydrological model (WEB-DHM+DVM) in Volta River Basin, with basin-averaged leaf area index from model (blue solid line) and AVHRR satellite-derived product (red rectangles).

  16. Assessing Geomorphic and Vegetative Responses to Environmental Flows in the Willamette River Basin

    Science.gov (United States)

    Mangano, J.; Jones, K.; Wallick, R.; Bach, L.; Olson, M.; Bervid, H.

    2015-12-01

    On regulated rivers, restoring flow regimes is a process-based restoration approach that may strongly affect downstream ecosystems. Developing realistic flow targets with meaningful geomorphic and ecological benefits, however, is challenging. For instance, hydraulic, geomorphic and biological processes are affected by more than manipulating water release—sediment supply and transport conditions also require consideration. Also, funding and programmatic directives rarely require the monitoring necessary to adaptively manage environmental flow programs. Recent research in the Willamette River basin in support of the Sustainable Rivers Project (SRP) demonstrates how such a monitoring program can be implemented. At the reach scale, initial efforts have assessed geomorphic and vegetative changes in alluvial sections of the Middle Fork Willamette and McKenzie Rivers using repeat mapping from aerial photographs and flow analyses. Overall, both rivers are largely stable because of reduced discharge, bed-material supply and local revetments, but some reaches of the McKenzie River are more dynamic, perhaps reflecting greater inputs of sediment from unregulated tributaries and higher magnitude peak flows. Repeat, reach-scale mapping on the Middle Fork Willamette River shows that frequent bankfull flows are able to scour minimally vegetated gravel bars and sustain a patchwork of actively shifting bed-material sediment. Repeat mapping on the McKenzie River in summer 2015 will reveal insights about the geomorphic effectiveness of bankfull flows. At the site scale, monitoring at two bars in summer 2015 is linking streamflow with the establishment of black cottonwood. Lastly, a review of hydrographs from 2000-2015 and retrospectively applying stakeholder-defined flow targets showed substantial variability in meeting objectives for the timing and types of flows under traditional regulated conditions and the SRP. Altogether, these related efforts help link streamflow, geomorphic

  17. Exploring field vegetation reflectance as an indicator of soil contamination in river floodplains.

    Science.gov (United States)

    Kooistra, L; Salas, E A L; Clevers, J G P W; Wehrens, R; Leuven, R S E W; Nienhuis, P H; Buydens, L M C

    2004-01-01

    This study investigated the relation between vegetation reflectance and elevated concentrations of the metals Ni, Cd, Cu, Zn and Pb in river floodplain soils. High-resolution vegetation reflectance spectra in the visible to near-infrared (400-1350 nm) were obtained using a field radiometer. The relations were evaluated using simple linear regression in combination with two spectral vegetation indices: the Difference Vegetation Index (DVI) and the Red-Edge Position (REP). In addition, a multivariate regression approach using partial least squares (PLS) regression was adopted. The three methods achieved comparable results. The best R(2) values for the relation between metals concentrations and vegetation reflectance were obtained for grass vegetation and ranged from 0.50 to 0.73. Herbaceous species displayed a larger deviation from the established relationships, resulting in lower R(2) values and larger cross-validation errors. The results corroborate the potential of hyperspectral remote sensing to contribute to the survey of elevated metal concentrations in floodplain soils under grassland using the spectral response of the vegetation as an indicator. Additional constraints will, however, have to be taken into account, as results are resolution- and location-dependent.

  18. Hysteresis Effect of Runoff of the Heihe River on Vegetation Cover in the Ejina Oasis in Northwestern China

    Science.gov (United States)

    JIN, Xiaomei; HU, Guangcheng; LI, Wenmei

    The relationship between vegetation growth and groundwater in arid areas is one of the most actively researching topics in ecohydrology. On account of little precipitation, the oasis is the only form of sustenance for living and economic development, for the local people in the arid areas of Northwest China. During recent years, with the increase of water consumption in the middle stream area of the Heihe river basin, the incoming water has decreased gradually and the area of the Ejina oasis in the downstream area has decreased continuously. It has caused lake drying, land desertification, and eco-environmental degradation. The vegetation growth of the oasis has a close relationship with the water resources. Therefore, research on the quantitative relationship between the runoff and the vegetation growth has significance in improving the eco-environment, and balancing the contradiction of water consumption and reasonable allocation of the water resources in the Heihe river basin. Combined with remote sensing data and runoff of the Heihe river, the quantitative relationship between the vegetation growth of the Ejina oasis and the runoff of the Heihe river has been established from the regional scale in this study. The result indicates that the growth of oasis vegetation depends on the runoff of the Heihe river and the groundwater. The time lag of the impact of the runoff of the river on the vegetation cover of the Ejina oasis is one year, and the groundwater links the vegetation cover and the runoff by this hysteresis effect.

  19. Dynamics of Bottomland Geomorphology and Vegetation Along a Dammed, Arid Region River: Implications for Streamflow Management

    Science.gov (United States)

    Shafroth, P. B.; House, P. K.

    2007-05-01

    In arid and semiarid western North America, floodplain forests dominated by native cottonwood and willow trees are highly valued as wildlife habitat and preferred recreation sites and are thus the focus of conservation efforts. The Bill Williams River harbors some of the most extensive native floodplain forests in the lower Colorado River region. Our work is aimed at understanding the dynamics of the Bill Williams River floodplain forests, in the context of pre- and post-dam hydrology and geomorphology. We have mapped bottomland geomorphology and vegetation using seven sets of orthorectified aerial photographs spanning more than 50 years. Two sets of photos (1953 and 1964) pre-date the completion of Alamo Dam, a large flood control structure; and three sets of photos (1996, 2002, and 2005) are from an era during which streamflow downstream of the dam has been managed to promote the establishment and survival of native floodplain forest. Comparison of the aerial photographs to LiDAR data collected in 2005 is providing a framework for quantifying changes in valley bottom morphology and estimating reach-scale changes in volumes of stored and evacuated sediment between 1953 and 2005. Furthermore, comparison of the extent of pre-dam active channel in 1953 with the extent of floodwaters from a regulated moderate flood in 2005 provides an approximation of the predominant patterns of aggradation and degradation in the system over this interval of time. Flood magnitude on the Bill Williams has been dramatically reduced since the closure of Alamo Dam in 1968, and low flows have increased considerably since 1979. Channels along the Bill Williams R. narrowed an average of 111 m (71 %) between 1953 and 1987, with most narrowing occurring after dam closure. Multiple regression analysis revealed significant relationships among flood power, summer flows, intermittency (independent variables) and channel width (dependent variable). Concurrent with channel narrowing was an expansion

  20. Are Vegetative Reproduction Capacities the Cause of Widespread Invasion of Eurasian Salicaceae in Patagonian River Landscapes?

    OpenAIRE

    Thomas, Lisa K.; Lena Tölle; Birgit Ziegenhagen; Ilona Leyer

    2012-01-01

    In recent decades, invasive willows and poplars (Salicaceae) have built dense floodplain forests along most of the rivers in Patagonia, Argentina. These invasion processes may affect Salix humboldtiana as the only native floodplain tree species in this region. It is assumed, that the property to reproduce vegetatively can play an important role in the establishment of invasive species in their new range. Thus, in order to contribute to a better understanding of willow and poplar invasions in ...

  1. [The inversion processing of vegetation biomass along Yongding River based on multispectral information].

    Science.gov (United States)

    He, Cheng; Feng, Zhong-Ke; Han, Xu; Sun, Meng-Ying; Gong, Yin-Xi; Gao, Yuan; Dong, Bin

    2012-12-01

    Researching on vegetation biomass using the traditional measurement method is time-consuming and hard sledding, and prediction precision of biomass is always not good because of uncertain influencing factors. The present article aims at the current situation of Hebei-Beijing reach along Yongding River, using the Thematic Mapper data in this place on 20th July 2009 as source data, with the 30 meters Digital Elevation Model data in Beijing and other auxiliary information, meanwhile through field observation data, to find out the possible functional relationship along vegetation biomass and remote sensing image factor. The authros sorted out the vegetation biomass and remote sensing image factor on the sample plot, then set up an inverse model through multiple linear regression analysis, and analyzed the precision of inverse model. After calculating the measured value and predicted value, the authors got the global relative error is -0.025%, the average relative error is -0.016%, and the general predictive precision is 84.56%. The establishment of this model is able to investigate eco-environmental factors on large range timely, quickly and accurately, also can provide the experimental base for the eco-environmental survey on river basin, and make the foundation for the problem diagnosis of ecological environment and the research on ecosystem degradation mechanism of Yongding River.

  2. Evolution of the vegetation system in the Heihe River basin in the last 2000 years

    Directory of Open Access Journals (Sweden)

    S. Li

    2017-08-01

    Full Text Available The response of vegetation systems to the long-term changes in climate, hydrology, and social–economic conditions in river basins is critical for sustainable river basin management. This study aims to investigate the evolution of natural and crop vegetation systems in the Heihe River basin (HRB over the past 2000 years. Archived Landsat images, historical land use maps and hydrological records were introduced to derive the long-term spatial distribution of natural and crop vegetation and the corresponding biomass levels. The major findings are that (1 both natural and crop vegetation experienced three development stages: a pre-development stage (before the Republic of China, a rapid development stage (Republic of China – 2000, and a post-development stage (after 2000. Climate and hydrological conditions did not show significant impacts over crop vegetation, while streamflow presented synchronous changes with natural vegetation in the first stage. For the second stage, warmer temperature and increasing streamflow were found to be important factors for the increase in both natural and crop vegetation in the middle reaches of the HRB. For the third stage, positive climate and hydrological conditions, together with policy interventions, supported the overall vegetation increase in both the middle and lower HRB; (2 there was a significantly faster increase in crop biomass than that of native vegetation since 1949, which could be explained by the technological development; and (3 the ratio of natural vegetation to crop vegetation decreased from 16 during the Yuan Dynasty to about 2.2 since 2005. This ratio reflects the reaction of land and water development to a changing climate and altering social–economic conditions at the river basin level; therefore, it could be used as an indicator of water and land management at river basins.

  3. Geomorphic and vegetation processes of the Willamette River floodplain, Oregon: current understanding and unanswered science questions

    Science.gov (United States)

    Wallick, J. Rose; Jones, Krista L.; O'Connor, Jim E.; Keith, Mackenzie K.; Hulse, David; Gregory, Stanley V.

    2013-01-01

    decrease bed-material supply by an unknown amount because they limit bank erosion and entrainment of stored sediment. The rivers, geomorphic floodplain, and vegetation within the study area have changed noticeably in response to the alterations in floods and coarse sediment and wood transport. Widespread decreases have occurred in the rates of meander migration and avulsions and the number and diversity of landforms such as gravel bars, islands, and side channels. Dynamic and, in some cases, multi-thread river segments have become stable, single-thread channels. Preliminary observations suggest that forest area has increased within the active channel, further reducing the area of unvegetated gravel bars. Alterations to floods and sediment transport and ongoing channel, floodplain, and vegetation responses result in a modern Willamette River Basin. Here, the floodplain influenced by the modern flow and sediment regimes, or the functional floodplain, is narrower and inset with the broader and older geomorphic floodplain. The functional floodplain is flanked by higher elevation relict floodplain features that are no longer inundated by modern floods. The corridor of present- day active channel surfaces is narrower, enabling riparian vegetation to establish on formerly active gravel bar surfaces. The modern Willamette River Basin with its fundamental changes in the flood, sediment transport, and large wood regimes has implications for future habitat conditions. System-wide future trends probably include narrower floodplains and a lower diversity of landforms and habitats along the Willamette River and its major tributaries compared to historical patterns and today. Furthermore, specific conditions and future trends will probably vary between geologically stable, anthropogenically stable, and dynamic reaches. The middle and lower segments of the Willamette River are geologically stable, whereas the South Santiam and Middle Fork Willamette Rivers were historically dynamic, but

  4. Plant succession after hydrologic disturbance: Inferences from contemporary vegetation on a chronosequence of bars, Willamette River, Oregon, USA

    Science.gov (United States)

    Historic unconstrained, unregulated streamflow along the upper mainstem of the Willamette River, Oregon, produced a floodplain of coalescent bars supporting a mosaic of vegetation patches. We sampled the contemporary vegetation of 42 bars formed 3 to 64 + years ago in four, 1 km...

  5. Sea-level Rise Impacts on Hudson River Marshes and their Vegetation Zonation

    Science.gov (United States)

    Hooks, A.; Nitsche, F. O.

    2016-12-01

    Rising sea levels may cause tidal marshes to be vulnerable to submergence and affect their ability to perform ecosystem services. However, tidal marshes are dynamic ecosystems that can adapt to sea-level rise through inland migration and vertical growth. This study examines how four tidal marshes on the Hudson River (Piermont Marsh, Iona Island Marsh, Tivoli Bays, and Stockport Flats) would be affected by 0.5m, 1m, and 1.5m of sea-level rise by 2100. Using high-resolution LiDAR elevation data and vegetation data, we mapped sea-level rise projections in GIS, accounting for current accretion rates unique to each marsh. We calculated the submerged area of each marsh and analyzed how vegetation zonation in each marsh is expected to change due to rising sea levels. We found that the steep topography of the Hudson River banks limits the marshes' ability to migrate inland, emphasizing the role of elevation-building processes in adaptation. The marshes studied would experience minimal to no inundation under lower rates of sea-level rise such as 0.5m by 2100. At higher projected rates of sea-level rise (1.5m by 2100), Piermont Marsh and Tivoli Bays would experience significant inundation while Iona Island marsh and Stockport Flats would be less affected. Overall, Stockport Flats is projected to be the marsh most resilient to sea-level rise due to its higher accretion rate and its topography. Rising sea levels are also expected to change the areas of vegetation zones, with upland, high marsh, and mid marsh zones generally declining in area and with subtidal and low marsh vegetation zones generally expanding under high rates of sea-level rise. Understanding the impacts of sea-level rise on Hudson River marshes enables long-term planning to adapt to potential changes in marsh ecosystem services and could motivate and inform conservation efforts.

  6. River flow is critical for vegetation dynamics: Lessons from multi-scale analysis in a hyper-arid endorheic basin.

    Science.gov (United States)

    Shen, Qin; Gao, Guangyao; Lü, Yihe; Wang, Shuai; Jiang, Xiaohui; Fu, Bojie

    2017-12-15

    Knowledge of the spatio-temporal responses of vegetation dynamics to hydro-climatic factors is important to assess ecological restoration efforts in arid and semiarid areas. In this study, the vegetation dynamics during 2000-2015 were investigated in the downstream area of the Heihe River Basin (HRB) in Northwest China where an ecological water diversion project (EWDP) commenced in 2000. The spatio-temporal relationships between vegetation cover and climatic factors (precipitation and temperature) and available water resources (river flow and groundwater) were determined. The results indicated that the mean growing season NDVI increased significantly during the period of 2000-2015, and the area of East Juyan Lake (EJL) enlarged to 36.4km(2) in 2010. The scale effect of the relationships between NDVI and hydro-climatic factors was obvious. At the catchment scale, changes of NDVI were not significantly correlated with climatic factors, but significantly related with the antecedent 1-year river flow. River flow played an important role in vegetation growth within approximately 2000m distance from the river bank. At the pixel scale, the changes of NDVI were significantly positive with temperature and river flow in 17.40% and 7.14% of the study area, respectively, whereas significant relationship between NDVI and precipitation occurred in only 0.65% of study area. The suitable water table depth for vegetation growth was between 1.8 and 3.5m. The increased river flow and recovered groundwater due to the EWDP were critical for the improvement of vegetation cover, whereas the riparian vegetation degraded along some parts of the river bank. It is important to improve integrated watershed management with consideration of spatio-temporal lagged hydro-ecological connections in the study area. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Drought and vegetation analysis in Tarsus River Basin (Southern Turkey using GIS and Remote Sensing data

    Directory of Open Access Journals (Sweden)

    Celalettin Duran

    2015-12-01

    Full Text Available In this study, the effects of topographic variables on drought and vegetation in dry season have been examined. Distributions of dry conditions in Tarsus River Basin were derived using the NDVI, NDMI indexes and LST (Land Surface Temperature from landsat8 image bands. There is large difference in elevation in the study area. Local climatic conditions are formed under the influence of altitude and morphological structure. Narrow and deep valleys in the topography create more moderate temperature/moisture conditions and are the main distribution area of tall forest vegetation. High radiation in the highest plateau system and, extreme temperature/moisture values led short-lived herbaceous vegetation to spread. Due to high insolation/temperature and restricted marine affect, establishment of scrub vegetation can be observed both in mid-elevation and south-sloping plateau of the study area. Anthropogenic agricultural fields form the land surface with the potential of high temperature/evapotranspiration rate in harvesting periods. Broadleaf plant species spread in areas close to the base of the valley stream. Plantation forest has been created in areas of near-shore sand dunes and very small delta (marsh. Variability in topography also increases the width of the combination of factors that shape the vegetation. This also enables the number of taxa to increase and unusual taxa to co-exist.

  8. Monitoring Earthquake-Damaged Vegetation after the 2008 Wenchuan Earthquake in the Mountainous River Basins, Dujiangyan County

    Directory of Open Access Journals (Sweden)

    Huaizhen Zhang

    2015-05-01

    Full Text Available The 2008 Wenchuan earthquake destroyed large areas of vegetation in the Baisha River and Longxi River basins, in Dujiangyan County, China. There were several debris flow events in these mountainous river basins after 2008. Currently, these damaged vegetation areas are in various stages of recovery. This recovery vegetation improves the resistance of slopes to both surficial erosion and mass wasting. We introduce a probabilistic approach to determining the relationships between damaged vegetation and slope materials’ stability, and model the sediment and flow (hydrological connectivity index to detect the hydrological changes in a given river basin, using the multi-temporal (1994–2014 remote-sensing images to monitor the vegetation recovery processes. Our results demonstrated that the earthquake-damaged vegetation areas have coupling relationships with topographic environment and slope material properties, and can be used to assess the slope material stability. Further, our analysis results showed that the areas with horizontal distance to river streams <500 m are areas that actively contribute sediment to the stream channel network, and are main material sources for debris flow processes in one given mountainous basin.

  9. The role of riparian vegetation density, channel orientation and water velocity in determining river temperature dynamics

    Science.gov (United States)

    Garner, Grace; Malcolm, Iain A.; Sadler, Jonathan P.; Hannah, David M.

    2017-10-01

    A simulation experiment was used to understand the importance of riparian vegetation density, channel orientation and flow velocity for stream energy budgets and river temperature dynamics. Water temperature and meteorological observations were obtained in addition to hemispherical photographs along a ∼1 km reach of the Girnock Burn, a tributary of the Aberdeenshire Dee, Scotland. Data from nine hemispherical images (representing different uniform canopy density scenarios) were used to parameterise a deterministic net radiation model and simulate radiative fluxes. For each vegetation scenario, the effects of eight channel orientations were investigated by changing the position of north at 45° intervals in each hemispheric image. Simulated radiative fluxes and observed turbulent fluxes drove a high-resolution water temperature model of the reach. Simulations were performed under low and high water velocity scenarios. Both velocity scenarios yielded decreases in mean (≥1.6 °C) and maximum (≥3.0 °C) temperature as canopy density increased. Slow-flowing water resided longer within the reach, which enhanced heat accumulation and dissipation, and drove higher maximum and lower minimum temperatures. Intermediate levels of shade produced highly variable energy flux and water temperature dynamics depending on the channel orientation and thus the time of day when the channel was shaded. We demonstrate that in many reaches relatively sparse but strategically located vegetation could produce substantial reductions in maximum temperature and suggest that these criteria are used to inform future river management.

  10. Radiological survey of shoreline vegetation from the Hanford Reach of the Columbia River, 1990--1992

    Energy Technology Data Exchange (ETDEWEB)

    Antonio, E.J.; Poston, T.M.; Rickard, W.H. Jr.

    1993-09-01

    A great deal of interest exists concerning the seepage of radiologically contaminated groundwater into the Columbia River where it borders the US Department of Energy`s Hanford Site (Hanford Reach). Areas of particular interest include the 100-N Area, the Old Hanford Townsite, and the 300 Area springs. While the radiological character of the seeps and springs along the Hanford Site shoreline has been studied, less attention has been given to characterizing the radionuclides that may be present in shoreline vegetation. The objective of this study was to characterize radionuclide concentrations in shoreline plants along the Hanford Reach of the Columbia River that were usable by humans for food or other purposes. Vegetation in two areas was found to have elevated levels of radionuclides. Those areas were the 100-N Area and the Old Hanford Townsite. There was also some indication of uranium accumulation in milfoil and onions collected from the 300 Area. Tritium was elevated above background in all areas; {sup 60}Co and {sup 9O}Sr were found in highest concentrations in vegetation from the 100-N Area. Technetium-99 was found in 2 of 12 plants collected from the Old Hanford Townsite and 1 of 10 samples collected upstream from the Vernita Bridge. The concentrations of {sup 137}Cs, {sup 238}Pu, {sup 239,240}Pu, and isotopes of uranium were just above background in all three areas (100-N Area, Old Hanford Townsite, and 300 Area).

  11. The long-term legacy of geomorphic and riparian vegetation feedbacks on the dammed Bill Williams River, Arizona, USA

    Science.gov (United States)

    Kui, Li; Stella, John C.; Shafroth, Patrick B.; House, Kyle; Wilcox, Andrew C.

    2017-01-01

    On alluvial rivers, fluvial landforms and riparian vegetation communities codevelop as a result of feedbacks between plants and abiotic processes. The influence of vegetation on river channel and floodplain geomorphology can be particularly strong on dammed rivers with altered hydrology and reduced flood disturbance. We used a 56-year series of aerial photos on the dammed Bill Williams River (Arizona, USA) to investigate how (a) different woody riparian vegetation types influence river channel planform and (b) how different fluvial landforms drive the composition of riparian plant communities over time. We mapped vegetation types and geomorphic surfaces and quantified how relations between fluvial and biotic processes covaried over time using linear mixed models. In the decades after the dam was built, woody plant cover within the river's bottomland nearly doubled, narrowing the active channel by 60% and transforming its planform from wide and braided to a single thread and more sinuous channel. Compared with native cottonwood–willow vegetation, nonnative tamarisk locally induced a twofold greater reduction in channel braiding. Vegetation expanded at different rates depending on the type of landform, with tamarisk cover on former high-flow channels increasing 17% faster than cottonwood–willow. Former low-flow channels with frequent inundation supported a greater increase in cottonwood–willow relative to tamarisk. These findings give insight into how feedbacks between abiotic and biotic processes in river channels accelerate and fortify changes triggered by dam construction, creating river systems increasingly distinct from predam ecological communities and landforms, and progressively more resistant to restoration of predam forms and processes.

  12. Vegetation cover, avoided erosion and water quality in high Andean wetlands, Yeso River Basin

    Science.gov (United States)

    León, Alejandro; Soto, Jorge; Seguel, Oscar; Pérez, Javier; Osses, Daniela; Leiva, Nicolás; Zerega, Linka

    2017-04-01

    Wetlands on the high Andes mountains near Santiago de Chile have been impacted by overgrazing and off-road tourists. We studied wetlands in El Yeso River basin. In February 2015 we established 36 exclusions and measured vegetation cover and height, biomass production in and out the exclusions starting in October. Water and undisturbed soil samples were collected. Data were analyzed statistically to estimate i) the recovery of vegetation, and ii) the influence of grazing and vehicle traffic on vegetation loss, and iii) impacts on soil and water quality. In areas with less intense traffic, the difference in vegetation coverage in and out the exclusions is 22% (± 11.4%); in areas with more intense traffic this difference is 16% (± 16%). Height of vegetation, in the less intense traffic areas, ranges from 6.25 cm (± 2.8) to 13.32 cm (± 6.3). With higher traffic it varies between 6.9 cm (± 3.1) and 13.6 cm (± 5.4). Biomass varies between 0.06 kg DM/m2 to 0.57 kg DM/m2 depending on botanical composition and date. After water circulates through the wetlands its content of nitrogen increases 37.33% to 0.37 mg N/l and the fecal coliforms 66.67% to 0.67 MPN/100 ml, because of cattle. On the contrary, turbidity decreases 20.67% to 0.21 UNT because sediments are captured by vegetation. We also estimated an avoided erosion rate, ranging between 1.23% and 31.87% (depending on the slope) due to the increase in coverage within the exclusions.

  13. Are vegetative reproduction capacities the cause of widespread invasion of Eurasian Salicaceae in Patagonian river landscapes?

    Directory of Open Access Journals (Sweden)

    Lisa K Thomas

    Full Text Available In recent decades, invasive willows and poplars (Salicaceae have built dense floodplain forests along most of the rivers in Patagonia, Argentina. These invasion processes may affect Salix humboldtiana as the only native floodplain tree species in this region. It is assumed, that the property to reproduce vegetatively can play an important role in the establishment of invasive species in their new range. Thus, in order to contribute to a better understanding of willow and poplar invasions in riparian systems and to assess the potential impacts on S. humboldtiana the vegetative reproduction capacities of native and invasive Salicaceae were analysed. In a greenhouse experiment, we studied cutting survival and growth performance of the three most dominant invasive Salicaceae of the Patagonian Río Negro region (two Salix hybrids and Populus spec., as well as S. humboldtiana, taking into account three different moisture and two different soil conditions. In a subsequent experiment, the shoot and root biomass of cuttings from the former experiment were removed and the bare cuttings were replanted to test their ability to re-sprout. The two invasive willow hybrids performed much better than S. humboldtiana and Populus spec. under all treatment combinations and tended to re-sprout more successfully after repeated biomass loss. Taking into account the ecology of vegetative and generative recruits of floodplain willows, the results indicate that the more vigorous vegetative reproduction capacity can be a crucial property for the success of invasive willow hybrids in Patagonia being a potential threat for S. humboldtiana.

  14. Are vegetative reproduction capacities the cause of widespread invasion of Eurasian Salicaceae in Patagonian river landscapes?

    Science.gov (United States)

    Thomas, Lisa K; Tölle, Lena; Ziegenhagen, Birgit; Leyer, Ilona

    2012-01-01

    In recent decades, invasive willows and poplars (Salicaceae) have built dense floodplain forests along most of the rivers in Patagonia, Argentina. These invasion processes may affect Salix humboldtiana as the only native floodplain tree species in this region. It is assumed, that the property to reproduce vegetatively can play an important role in the establishment of invasive species in their new range. Thus, in order to contribute to a better understanding of willow and poplar invasions in riparian systems and to assess the potential impacts on S. humboldtiana the vegetative reproduction capacities of native and invasive Salicaceae were analysed. In a greenhouse experiment, we studied cutting survival and growth performance of the three most dominant invasive Salicaceae of the Patagonian Río Negro region (two Salix hybrids and Populus spec.), as well as S. humboldtiana, taking into account three different moisture and two different soil conditions. In a subsequent experiment, the shoot and root biomass of cuttings from the former experiment were removed and the bare cuttings were replanted to test their ability to re-sprout. The two invasive willow hybrids performed much better than S. humboldtiana and Populus spec. under all treatment combinations and tended to re-sprout more successfully after repeated biomass loss. Taking into account the ecology of vegetative and generative recruits of floodplain willows, the results indicate that the more vigorous vegetative reproduction capacity can be a crucial property for the success of invasive willow hybrids in Patagonia being a potential threat for S. humboldtiana.

  15. Response of Soil Fungi Community Structure to Salt Vegetation Succession in the Yellow River Delta.

    Science.gov (United States)

    Wang, Yan-Yun; Guo, Du-Fa

    2016-10-01

    High-throughput sequencing technology was used to reveal the composition and distribution of fungal community structure in the Yellow River Delta under bare land and four kinds of halophyte vegetation (saline seepweed, Angiospermae, Imperata and Apocynum venetum [A. venetum]). The results showed that the soil quality continuously improved with the succession of salt vegetation types. The soil fungi richness of mild-salt communities (Imperata and A. venetum) was relatively higher, with Shannon index values of 5.21 and 5.84, respectively. The soil fungi richness of severe-salt-tolerant communities (saline seepweed, Angiospermae) was relatively lower, with Shannon index values of 4.64 and 4.66, respectively. The UniFrac metric values ranged from 0.48 to 0.67 when the vegetation was in different succession stages. A total of 60,174 valid sequences were obtained for the five vegetation types, and they were classified into Ascomycota, Basidiomycota, Chytridiomycota, Glomeromycota and Mucoromycotina. Ascomycota had the greatest advantage among plant communities of Imperata and A. venetum, as indicated by relative abundances of 2.69 and 69.97 %, respectively. Basidiomycota had the greatest advantage among mild-salt communities of saline seepweed and Angiospermae, with relative abundances of 9.43 and 6.64 %, respectively. Soil physical and chemical properties were correlated with the distribution of the fungi, and Mucor was significantly correlated with soil moisture (r = 0.985; P fungi were influenced by each other.

  16. Are Vegetative Reproduction Capacities the Cause of Widespread Invasion of Eurasian Salicaceae in Patagonian River Landscapes?

    Science.gov (United States)

    Thomas, Lisa K.; Tölle, Lena; Ziegenhagen, Birgit; Leyer, Ilona

    2012-01-01

    In recent decades, invasive willows and poplars (Salicaceae) have built dense floodplain forests along most of the rivers in Patagonia, Argentina. These invasion processes may affect Salix humboldtiana as the only native floodplain tree species in this region. It is assumed, that the property to reproduce vegetatively can play an important role in the establishment of invasive species in their new range. Thus, in order to contribute to a better understanding of willow and poplar invasions in riparian systems and to assess the potential impacts on S. humboldtiana the vegetative reproduction capacities of native and invasive Salicaceae were analysed. In a greenhouse experiment, we studied cutting survival and growth performance of the three most dominant invasive Salicaceae of the Patagonian Río Negro region (two Salix hybrids and Populus spec.), as well as S. humboldtiana, taking into account three different moisture and two different soil conditions. In a subsequent experiment, the shoot and root biomass of cuttings from the former experiment were removed and the bare cuttings were replanted to test their ability to re-sprout. The two invasive willow hybrids performed much better than S. humboldtiana and Populus spec. under all treatment combinations and tended to re-sprout more successfully after repeated biomass loss. Taking into account the ecology of vegetative and generative recruits of floodplain willows, the results indicate that the more vigorous vegetative reproduction capacity can be a crucial property for the success of invasive willow hybrids in Patagonia being a potential threat for S. humboldtiana. PMID:23226531

  17. Winter soil respiration from different vegetation patches in the Yellow River Delta, China.

    Science.gov (United States)

    Han, Guangxuan; Yu, Junbao; Li, Huabing; Yang, Liqiong; Wang, Guangmei; Mao, Peili; Gao, Yongjun

    2012-07-01

    Vegetation type and density exhibited a considerable patchy distribution at very local scales in the Yellow River Delta, due to the spatial variation of soil salinity and water scarcity. We proposed that soil respiration is affected by the spatial variations in vegetation type and soil chemical properties and tested this hypothesis in three different vegetation patches (Phragmites australis, Suaeda heteroptera and bare soil) in winter (from November 2010 to April 2011). At diurnal scale, soil respiration all displayed single-peak curves and asymmetric patterns in the three vegetation patches; At seasonal scale, soil respiration all declined steadily until February, and then increased to a peak in next April. But, the magnitude of soil respiration showed significant differences among the three sites. Mean soil respiration rates in winter were 0.60, 0.45 and 0.17 μmol CO(2) m(-2) s(-1) for the Phragmites australis, Suaeda heteroptera and bare soil, respectively. The combined effect of soil temperature and soil moisture accounted for 58-68 % of the seasonal variation of winter soil respiration. The mean soil respiration revealed positive and linear correlations with total N, total N and SOC storages at 0-20 cm depth, and plant biomass among the three sites. We conclude that the patchy distribution of plant biomass and soil chemical properties (total C, total N and SOC) may affect decomposition rate of soil organic matter in winter, thereby leading to spatial variations in soil respiration.

  18. Parameterization of High Resolution Vegetation Characteristics using Remote Sensing Products for the Nakdong River Watershed, Korea

    Directory of Open Access Journals (Sweden)

    Hyun Il Choi

    2013-01-01

    Full Text Available Mesoscale regional climate models (RCMs, the primary tool for climate predictions, have recently increased in sophistication and are being run at increasingly higher resolutions to be also used in climate impact studies on ecosystems, particularly in agricultural crops. As satellite remote sensing observations of the earth terrestrial surface become available for assimilation in RCMs, it is possible to incorporate complex land surface processes, such as dynamics of state variables for hydrologic, agricultural and ecologic systems at the smaller scales. This study focuses on parameterization of vegetation characteristics specifically designed for high resolution RCM applications using various remote sensing products, such as Advanced Very High Resolution Radiometer (AVHRR, Système Pour l’Observation de la Terre-VEGETATION (SPOT-VGT and Moderate Resolution Imaging Spectroradiometer (MODIS. The primary vegetative parameters, such as land surface characteristics (LCC, fractional vegetation cover (FVC, leaf area index (LAI and surface albedo localization factors (SALF, are currently presented over the Nakdong River Watershed domain, Korea, based on 1-km remote sensing satellite data by using the Geographic Information System (GIS software application tools. For future high resolution RCM modeling efforts on climate-crop interactions, this study has constructed the deriving parameters, such as FVC and SALF, following the existing methods and proposed the new interpolation methods to fill missing data with combining the regression equation and the time series trend function for time-variant parameters, such as LAI and NDVI data at 1-km scale.

  19. Effects of stream flow intermittency on riparian vegetation of a semiarid region river (San Pedro River, Arizona)

    Science.gov (United States)

    Stromberg, J.C.; Bagstad, K.J.; Leenhouts, J.M.; Lite, S.J.; Makings, E.

    2005-01-01

    The San Pedro River in the southwestern United States retains a natural flood regime and has several reaches with perennial stream flow and shallow ground water. However, much of the river flows intermittently. Urbanization-linked declines in regional ground-water levels have raised concerns over the future status of the riverine ecosystem in some parts of the river, while restoration-linked decreases in agricultural ground-water pumping are expected to increase stream flows in other parts. This study describes the response of the streamside herbaceous vegetation to changes in stream flow permanence. During the early summer dry season, streamside herbaceous cover and species richness declined continuously across spatial gradients of flow permanence, and composition shifted from hydric to mesic species at sites with more intermittent flow. Hydrologic threshold values were evident for one plant functional group: Schoenoplectus acutus, Juncus torreyi, and other hydric riparian plants declined sharply in cover with loss of perennial stream flow. In contrast, cover of mesic riparian perennials (including Cynodon dactylon, an introduced species) increased at sites with intermittent flow. Patterns of hydric and mesic riparian annuals varied by season: in the early summer dry season their cover declined continuously as flow became more intermittent, while in the late summer wet season their cover increased as the flow became more intermittent. Periodic drought at the intermittent sites may increase opportunities for establishment of these annuals during the monsoonal flood season. During the late summer flood season, stream flow was present at most sites, and fewer vegetation traits were correlated with flow permanence; cover and richness were correlated with other environmental factors including site elevation and substrate nitrate level and particle size. Although perennial-flow and intermittent-flow sites support different streamside plant communities, all of the plant

  20. River basin soil-vegetation condition assessment applying mathematic simulation methods

    Science.gov (United States)

    Mishchenko, Natalia; Trifonova, Tatiana; Shirkin, Leonid

    2013-04-01

    Meticulous attention paid nowadays to the problem of vegetation cover productivity changes is connected also to climate global transformation. At the same time ecosystems anthropogenic transformation, basically connected to the changes of land use structure and human impact on soil fertility, is developing to a great extent independently from climatic processes and can seriously influence vegetation cover productivity not only at the local and regional levels but also globally. Analysis results of land use structure and soil cover condition influence on river basin ecosystems productive potential is presented in the research. The analysis is carried out applying integrated characteristics of ecosystems functioning, space images processing results and mathematic simulation methods. The possibility of making permanent functional simulator defining connection between macroparameters of "phytocenosis-soil" system condition on the basis of basin approach is shown. Ecosystems of river catchment basins of various degrees located in European part of Russia were chosen as research objects. For the integrated assessment of ecosystems soil and vegetation conditions the following characteristics have been applied: 1. Soil-productional potential, characterizing the ability of natural and natural-anthropogenic ecosystem in certain soil-bioclimatic conditions for long term reproduction. This indicator allows for specific phytomass characteristics and ecosystem produce, humus content in soil and bioclimatic parameters. 2. Normalized difference vegetation index (NDVI) has been applied as an efficient, remotely defined, monitoring indicator characterizing spatio-temporal unsteadiness of soil-productional potential. To design mathematic simulator functional simulation methods and principles on the basis of regression, correlation and factor analysis have been applied in the research. Coefficients values defining in the designed static model of phytoproductivity distribution has been

  1. Asynchronous changes in vegetation, runoff and erosion in the nile river watershed during the holocene.

    Directory of Open Access Journals (Sweden)

    Cécile L Blanchet

    Full Text Available The termination of the African Humid Period in northeastern Africa during the early Holocene was marked by the southward migration of the rain belt and the disappearance of the Green Sahara. This interval of drastic environmental changes was also marked by the initiation of food production by North African hunter-gatherer populations and thus provides critical information on human-environment relationships. However, existing records of regional climatic and environmental changes exhibit large differences in timing and modes of the wet/dry transition at the end of the African Humid Period. Here we present independent records of changes in river runoff, vegetation and erosion in the Nile River watershed during the Holocene obtained from a unique sedimentary sequence on the Nile River fan using organic and inorganic proxy data. This high-resolution reconstruction allows to examine the phase relationship between the changes of these three parameters and provides a detailed picture of the environmental conditions during the Paleolithic/Neolithic transition. The data show that river runoff decreased gradually during the wet/arid transition at the end of the AHP whereas rapid shifts of vegetation and erosion occurred earlier between 8.7 and ∼6 ka BP. These asynchronous changes are compared to other regional records and provide new insights into the threshold responses of the environment to climatic changes. Our record demonstrates that the degradation of the environment in northeastern Africa was more abrupt and occurred earlier than previously thought and may have accelerated the process of domestication in order to secure sustainable food resources for the Neolithic African populations.

  2. Remote Sensing of Aquatic Vegetation Coverage in the Kafue River, Zambia and Comparison to Climatic Variables

    Science.gov (United States)

    Mischler, J. A.; Abdalati, W.; Hussein, K.; Townsend, A. R.

    2013-12-01

    The Kafue River is the longest river in Zambia and is a major tributary of the Zambezi River. It is a vital source of fish, transportation, drinking water, and hydropower for much of Zambia's population, over half of whom live in the Kafue River basin. Like many important water bodies in developing countries the Kafue and its ecosystems face pollution from industrial, mining, agricultural, and domestic/sewage discharge. The Kafue River forms a wide and shallow wetland (the Kafue Flats) during the rainy season (Nov. - Apr.) which serves as habitat for diverse groups of birds and mammals. In recent years the unprecedented emergence of invasive aquatic vegetation such as the water hyacinth (Eichhornia crassipes) and Salvinia molesta have choked the river, degrading its ability to provide adequate habitat to promote biodiversity, ecosystem services, and hydropower. In addition, these plants provide additional habitat for mosquitoes (vectors for malaria) and aquatic snails (vectors of schistosomiasis). Nutrient-rich effluents are widely believed to contribute to the proliferation and explosive growth of this floating aquatic vegetation. The general methods for managing these aquatic weeds have included mechanical and physical removal, herbicides, and bio-control agents which have had very little impact. However, as in neighboring Lake Victoria, total weed coverage has fluctuated dramatically from year to year making evaluation of the efficacy of management programs difficult. The objectives of this study were to (1) generate the first record of aquatic plant coverage for a section of the Kafue River which is immediately downstream of a sugar plantation (a major source of nitrogen and phosphorus to the river) and (2) determine if plant coverage is correlated with any major climatic (ENSO, temperature, rainfall) or management (introduction of bio-control agents) indices. We utilized remote sensing techniques in conjunction with Landsat 4-5 TM and Landsat 7 ETM imagery for

  3. Influence of atmospheric rivers on vegetation productivity and fire patterns in the southwestern U.S.

    Science.gov (United States)

    Albano, Christine M.; Dettinger, Michael; Soulard, Christopher E.

    2017-01-01

    In the southwestern U.S., the meteorological phenomenon known as atmospheric rivers (ARs) has gained increasing attention due to its strong connections to floods, snowpacks, and water supplies in the West Coast states. Relatively less is known about the ecological implications of ARs, particularly in the interior Southwest, where AR storms are less common. To address this gap, we compared a chronology of AR landfalls on the west coast between 1989 and 2011 and between 25°N and 42.5°N to annual metrics of the normalized difference vegetation index (NDVI; an indicator of vegetation productivity) and daily resolution precipitation data to assess influences of AR-fed winter precipitation on vegetation productivity across the southwestern U.S. We mapped correlations between winter AR precipitation during landfalling ARs and (1) annual maximum NDVI and (2) area burned by large wildfires summarized by ecoregion during the same year as the landfalls and during the following year. Interannual variations of AR precipitation strongly influenced both NDVI and area burned by wildfire in some dryland ecoregions. The influence of ARs on dryland vegetation varied significantly depending on the latitude of landfall, with those ARs making landfall below 35°N latitude more strongly influencing these systems, and with effects observed as far as 1300 km from the landfall location. As climatologists' understanding of the synoptic patterns associated with the occurrence of ARs continues to evolve, an increased understanding of how AR landfalls, in aggregate, influence vegetation productivity and associated wildfire activity in dryland ecosystems may provide opportunities to better predict ecological responses to climate and climate change.

  4. Vegetation

    DEFF Research Database (Denmark)

    Epstein, H.E.; Walker, D.A.; Bhatt, U.S.;

    2012-01-01

    • Over the past 30 years (1982-2011), the Normalized Difference Vegetation Index (NDVI), an index of green vegetation, has increased 15.5% in the North American Arctic and 8.2% in the Eurasian Arctic. In the more southern regions of Arctic tundra, the estimated aboveground plant biomass has...

  5. The Distribution of Submersed Aquatic Vegetation in the Fresh and Oligohaline Tidal Potomac River, 2005

    Science.gov (United States)

    Rybicki, Nancy B.; Justiniano-Velez, Erika M.; Schenk, Edward R.; Baldizar, Julie M.; Hunter, Sarah E.

    2008-01-01

    Submersed aquatic vegetation (SAV) is a critical component of the Potomac River ecosystem. Though SAV provides important habitat for fauna and stabilizes bottom sediment, very dense beds may restrict recreational and commercial navigation. Exotic species of SAV are managed by the Metropolitan Washington Council of Governments Potomac Aquatic Plant Management Program (PAPMP). Selected beds of primarily exotic SAV species that limit navigation are harvested mechanically. The program began in 1986 when approximately 40 acres of plants were harvested from 18 sites (Metropolitan Washington Council of Governments 1987). Monitoring efforts are an effective means of quantifying the distribution and abundance of the exotic species, Hydrilla verticillata (hydrilla) and other SAV species. These annual surveys provide a basis for identifying large-scale changes and trends throughout the ecosystem and allow managers to evaluate the effectiveness of resource management policies based on a reliable scientific foundation (Rybicki and Landwehr, 2007). The U.S. Geological Survey (USGS) has monitored the distribution and composition of SAV beds in the fresh and oligohaline (salinity 0.5 to 5) tidal Potomac River since 1978 using transect sampling (1978 to 1981, 1985 to 1987, and 2002) and shoreline surveys (1983 to 2005). The Government of the District of Columbia has monitored the portion of the Potomac and Anacostia Rivers within Washington DC since 1998 (Rottman, 1999; Ryan, 2005, 2006). The species of SAV observed in beds in the tidal Potomac River are incorporated into the Virginia Institute of Marine Science (VIMS) annual report on SAV distribution in Chesapeake Bay. The VIMS report and methods are available at http://www.vims.edu/bio/sav (Orth et al., 2006). Additional publications concerning SAV distribution in the Potomac River can be found at http://water.usgs.gov/nrp/proj.bib/sav/wethome.htm.

  6. Effects of drought on birds and riparian vegetation in the Colorado River Delta, Mexico

    Science.gov (United States)

    Hinojosa-Huerta, Osvel; Nagler, Pamela L.; Carrillo-Guererro, Yamilett K.; Glenn, Edward P.

    2013-01-01

    The riparian corridor in the delta of the Colorado River in Mexico supports internationally important bird habitat. The vegetation is maintained by surface flows from the U.S. and Mexico and by a high, non-saline aquifer into which the dominant phreatophytic shrubs and trees are rooted. We studied the effects of a regional drought on riparian vegetation and avian abundance and diversity from 2002 to 2007, during which time surface flows were markedly reduced compared to the period from 1995 to 2002. Reduced surface flows led to a reduction in native tree cover but an increase in shrub cover, mostly due to an increase in Tamarix spp., an introduced halophytic shrub, and a reduction in Populus fremontii and Salix gooddingii trees. However, overall vegetation cover was unchanged at about 70%. Overall bird density and diversity were also unchanged, but riparian-obligate species tended to decrease in abundance, and generalist species increased. Although reduction in surface flows reduced habitat value and negatively impacted riparian-obligate bird species, portions of the riparian zone exhibited resilience. Surface flows are required to reduce soil salt levels and germinate new cohorts of native trees, but the main source of water supporting this ecosystem is the aquifer, derived from underflows from irrigated fields in the U.S. and Mexico. The long-term prospects for delta riparian habitats are uncertain due to expected reduced flows of river water from climate change, and land use practices that will reduce underflows to the riparian aquifer and increase salinity levels. Active restoration programs would be needed if these habitats are to be preserved for the future.

  7. Changes in aquatic vegetation and floodplain land cover in the Upper Mississippi and Illinois rivers (1989–2000–2010)

    Science.gov (United States)

    DeJager, Nathan R.; Rohweder, Jason J.

    2017-01-01

    Quantifying changes in the cover of river-floodplain systems can provide important insights into the processes that structure these landscapes as well as the potential consequences to the ecosystem services they provide. We examined net changes in 13 different aquatic and floodplain land cover classes using photo interpreted maps of the navigable portions of the Upper Mississippi River (UMR, above the confluence with the Ohio River) and Illinois River from 1989 to 2000 and from 2000 to 2010. We detected net decreases in vegetated aquatic area in nearly all river reaches from 1989 to 2000. The only river reaches that experienced a subsequent recovery of vegetated aquatic area from 2000 to 2010 were located in the northern portion of the UMR (above navigation pool 14) and two reaches in the Illinois River. Changes on the floodplain were dominated by urban development, which increased in nearly every river reach studied from 1989 to 2000. Agricultural lands declined in most river reaches from 2000 to 2010. The loss of agricultural land cover in the northern UMR was accompanied by increases in forest cover, whereas in the lower UMR and Illinois River, declines in agriculture were accompanied by increases in forest and shallow marsh communities. The changes in aquatic vegetation occupied between 5 and 20% of the total aquatic area and are likely associated with previously reported regional improvements in water clarity, while smaller (1–15% of the total floodplain area) changes in anthropogenic land cover types on the floodplain are likely driven by broad-scale socio-economic conditions.

  8. Changes in aquatic vegetation and floodplain land cover in the Upper Mississippi and Illinois rivers (1989-2000-2010).

    Science.gov (United States)

    De Jager, Nathan R; Rohweder, Jason J

    2017-02-01

    Quantifying changes in the cover of river-floodplain systems can provide important insights into the processes that structure these landscapes as well as the potential consequences to the ecosystem services they provide. We examined net changes in 13 different aquatic and floodplain land cover classes using photo interpreted maps of the navigable portions of the Upper Mississippi River (UMR, above the confluence with the Ohio River) and Illinois River from 1989 to 2000 and from 2000 to 2010. We detected net decreases in vegetated aquatic area in nearly all river reaches from 1989 to 2000. The only river reaches that experienced a subsequent recovery of vegetated aquatic area from 2000 to 2010 were located in the northern portion of the UMR (above navigation pool 14) and two reaches in the Illinois River. Changes on the floodplain were dominated by urban development, which increased in nearly every river reach studied from 1989 to 2000. Agricultural lands declined in most river reaches from 2000 to 2010. The loss of agricultural land cover in the northern UMR was accompanied by increases in forest cover, whereas in the lower UMR and Illinois River, declines in agriculture were accompanied by increases in forest and shallow marsh communities. The changes in aquatic vegetation occupied between 5 and 20% of the total aquatic area and are likely associated with previously reported regional improvements in water clarity, while smaller (1-15% of the total floodplain area) changes in anthropogenic land cover types on the floodplain are likely driven by broad-scale socio-economic conditions.

  9. Influence of pioneer vegetation on the morphodynamic evolution of a river bed

    Science.gov (United States)

    Schwarzwälder, Kordula; Cuchet, Matilde; Schlagenhauser, Mathias

    2016-04-01

    In a natural river the morphology and the evolution of the river bed is highly influenced by the vegetation in and along this river bed. To estimate these effects and influences, a pre-study was conducted in a lab-flume in the outside area of the Oskar-von-Miller-Institute of the TUM. In this flume an alternating flow regime with a change between floods and standard discharge was mimicking a natural flow regime. The experiment was started with an uniform and plane sand area were the flow regime should built a nature-like morphology. During the experiment, seeds of Alfalfa were added and the sprouting plants could influence the formation of the riverbed. The changes in the morphology were measured using photogrammetry and also a standard Kinect system. The results of the measurements shall be used as basis for a 3D numerical simulation. In addition we analyzed different plants and their sprouting behavior under different growing conditions to ensure the use of the most appropriate ones for this set-up. The experimental performance was based on the experiments of Tal and Paola 2010. Tal and Paola 2010: EARTH SURFACE PROCESSES AND LANDFORMS;Earth Surf. Process. Landforms 35, 1014-1028 (2010); Copyright Published online 9 February 2010 in Wiley InterScience; (www.interscience.wiley.com) DOI: 10.1002/esp.1908

  10. Assessing the performance of a riparian vegetation model in a river with a low slope and fine sediment.

    Science.gov (United States)

    Sanjaya, Kelum; Asaeda, Takashi

    2017-03-01

    Riparian ecosystems are threatened worldwide, necessitating conservation strategies. Numerical models tailored for specific geographic areas have been developed as management support tools. However, few models are suitable for multiple river conditions, and developing these models or evaluating their suitability has become an emerging topic. The dynamic riparian vegetation model (DRIPVEM) is a numerical model developed for steep and gravelly Japanese rivers, where it has been successfully tested. Our objective was to assess the performance of DRIPVEM in a river with a low slope and fine sediment, similar to the characteristics of continental rivers. A reach of the Hii River was selected for testing the model's ability to predict the distribution of Salix spp. (willow) and herbs, as well as herb biomass and tree age. The model was calibrated based on field investigations of a selected river section. Simulation of the studied reach was carried out for the past five decades, depending on data availability. Non-parametric tests were used to compare the simulated and observed results. The simulated and observed vegetation distribution maps agreed fairly well and the sensitivity of the model for simulation of trees, herbs and bare areas was greater than 0.6. The kappa coefficients of agreement values were 0.48 and 0.49, indicating fair agreement. Moreover, the simulated biomass and tree age agreed well with observation. We conclude that the DRIPVEM simulated the observed conditions in the Hii River well, indicating that the model is applicable to rivers characterized by low slope and fine sediment grain size.

  11. UAV Measurement of the 2015 Large Flood Impact in Kinugawa River on Riverine Vegetation and Channel Form Changes

    Science.gov (United States)

    Miyamoto, Hitoshi; Inoue, Toshiya; Chigasaki, Yuka

    2016-04-01

    This presentation gives the results of field observation for a flood impact on riverine environment measured by using an unmanned aerial vehicle (UAV). The flood we examined occurred on September 9-10, 2015 in Kinugawa River, Japan, owing to the heavy rainfall that brought tremendous volume of water on the Kanto and Tohoku regions of Japan. In Kinugawa River, the largest record flood occurred in this time, resulting in the levee failure and the corresponding flood disaster in Joso City located in the downstream part of Kinugawa River, as well as the large flood impact on the riverine environment in the Kinugawa channel network. In order to investigate the very initial state of the after-flood-impact throughout the channel network, 13 channel sections with 2 km in longitudinal length were chosen and observed in October 2015. Orthochromatic images of the river channel sections obtained by the UAV measurement with a geographic information system (GIS) were used for analyzing the changes in riverine vegetation distributions and channel form profiles. The results show that there exist three characteristic river segments having different impact-response states in vegetation and channel form changes. The river sections in the most upstream segment indicated severe damage of trees and herbs as well as large movement of gravel bed material, while those in the most downstream segment showed relatively small damage in vegetation distribution and small change in channel forms. Furthermore, relationships between the vegetation damage, channel deformation, channel slopes, and bed shear stresses calculated by a numerical simulation model were discussed in detail along the river network.

  12. Vegetation of the Elwha River estuary: Chapter 8 in Coastal habitats of the Elwha River, Washington--biological and physical patterns and processes prior to dam removal

    Science.gov (United States)

    Shafroth, Patrick B.; Fuentes, Tracy L.; Pritekel, Cynthia; Beirne, Matthew M.; Beauchamp, Vanessa B.; Duda, Jeffrey J.; Warrick, Jonathan A.; Magirl, Christopher S.

    2011-01-01

    The Elwha River estuary supports one of the most diverse coastal wetland complexes yet described in the Salish Sea region, in terms of vegetation types and plant species richness. Using a combination of aerial imagery and vegetation plot sampling, we identified 6 primary vegetation types and 121 plant species in a 39.7 ha area. Most of the estuary is dominated by woody vegetation types, with mixed riparian forest being the most abundant (20 ha), followed by riparian shrub (6.3 ha) and willow-alder forest (3.9 ha). The shrub-emergent marsh transition vegetation type was fourth most abundant (2.2 ha), followed by minor amounts of dunegrass (1.75 ha) and emergent marsh (0.2 ha). This chapter documents the abundance, distribution, and floristics of these six vegetation types, including plant species richness, life form, species origin (native or introduced), and species wetland indicator status. These data will serve as a baseline to which future changes can be compared, following the impending removal of Glines Canyon and Elwha Dams upstream on the Elwha River. Dam removals may alter many of the processes, materials, and biotic interactions that influence the estuary plant communities, including hydrology, salinity, sediment and wood transport, nutrients, and plant-microbe interactions.

  13. Vegetation Changes and the Relationship with Climate Variability in the Upper and Middle Reaches of the Nenjiang River Basin, China

    Science.gov (United States)

    Huang, F.; Wen, D. H.; Wang, P.

    2016-06-01

    To detect changes in vegetation is desirable for modeling and predicting interactions between land surface and atmosphere. Multitemporal series of SPOT VEGETATION NDVI dataset and meteorological data were integrated to interpret vegetation dynamics and the linkage with climate variations in the upper and middle reaches of the Nenjiang River Basin (NRB) from 1999 to 2010 using the correlation analysis and the rescaled range (R/S) analysis. The results demonstrate that annual NDVI increased slightly and 26.02% vegetation coverage of the study area significantly improved. The area of significantly decreased in vegetation cover took up 13.33% of the total land in spring. In autumn, 26.2% of the study area showed a significant vegetation increase. The improved activity of vegetation might reinforce in summer and autumn, while the decreasing tendency in spring might be persistent in the future. The yearly NDVI had significant positive linkages with precipitation and relative humidity. NDVI related significantly and negatively with temperature, sunshine hours and wind velocity, because they may have effects of increasing evapotranspiration and risk of drought and cold damage of vegetation. The variations of annual NDVI were much affected by summer temperature, relative humidity and sunshine duration in autumn and spring wind velocity. Seasonal NDVI decreased in parallel with elevated temperature, but there was no correlation between NDVI and precipitation. Spring temperature, relative humidity in summer and autumn contributed markedly to NDVI variations in the same season. The vegetation improving trend may induce by the warm-wetting climate in recent twelve years.

  14. Vegetation, substrate and hydrology in floating marshes in the Mississippi river delta plain wetlands, USA

    Science.gov (United States)

    Sasser, C.E.; Gosselink, J.G.; Swenson, E.M.; Swarzenski, C.M.; Leibowitz, N.C.

    1996-01-01

    In the 1940s extensive floating marshes (locally called 'flotant') were reported and mapped in coastal wetlands of the Mississippi River Delta Plain. These floating marshes included large areas of Panicum hemitomon-dominated freshwater marshes, and Spartina patens/Scirpus olneyi brackish marshes. Today these marshes appear to be quite different in extent and type. We describe five floating habitats and one non-floating, quaking habitat based on differences in buoyancy dynamics (timing and degree of floating), substrate characteristics, and dominant vegetation. All floating marshes have low bulk density, organic substrates. Nearly all are fresh marshes. Panicum hemitomon floating marshes presently occur within the general regions that were reported in the 1940's by O'Neil, but are reduced in extent. Some of the former Panicum hemitomon marshes have been replaced by seasonally or variably floating marshes dominated, or co-dominated by Sagittaria lancifolia or Eleocharis baldwinii. ?? 1996 Kluwer Academic Publishers.

  15. Vegetation and vascular flora of the Mekong River, Kratie and Steung Treng Provinces, Cambodia

    Directory of Open Access Journals (Sweden)

    James F. Maxwell

    2009-04-01

    Full Text Available A preliminary and detailed botanical survey of the islands in the Mekong River between Kratie and Steung Treng was done. This area includes the most biologically intact and threatened riparian and terrestrial ecosystems along the river in Cambodia. The vegetation includes six riverine zones and four terrestrial facies. Riverine habitats are mostly intact while the terrestrial vegetation ranges from destroyed to degraded. Effective conservation measures are required to stop further habitat destruction and loss of biodiversity. One new species, 23 records for the Cambodian flora, and a total of 690 species were collected. Detailed descriptions of all habitats, a database, and photographs are included. Increased exploitative human settlement in the area has caused drastic environmental changes with extensive deforestation and hunting. The forests are grazed, burned, logged, and often cleared for agricultural use without effective control. Sustainable management and scientifically acceptable development must be implemented before the area is totally ruined. Properly conceived reforestation is urgently required as well as a conservation education project aimed directly at the people living in the area. Unless effective restraints are implemented the area will become biologically destitute and will not be able to provide the natural resources that people require--in short, the area will become uninhabitable. Restoration of degraded or destroyed places will be impossible or far more difficult than conservation and intelligent management of presently endangered places. The potential for profitable eco-tourism should also be considered since tourists will certainly want to visit natural ecosystems on some of the islands. Only if local people are directly involved in eco-tourism and understand the necessity of conservation can this activity be successful. It is strongly recommended that continued botanical research be conducted in the area in order to

  16. Bioavailability of iron and zinc in green leafy vegetables growing in river side and local areas of Allahabad district

    Directory of Open Access Journals (Sweden)

    Bhawna Srivastava

    2014-01-01

    Full Text Available Introduction: Green Leafy Vegetables (GLVs are the treasure trove of many micronutrients.Objective: The aim of the study is to find out the commonly growing vegetables in river side and local areas of Allahabad district and to access the bioavailability of iron and zinc in selected green leafy vegetables of river side and local areas of Allahabad district.Methods: Five to four commonly grown green leafy vegetables were selected from the Arailghat, Baluaghat, Gaughat, Mahewa, Muirabad, Rajapur, Rasullabad for the study. Total iron and zinc in sample were estimated by AOAC (2005 and bioavailability of zinc and iron from various food samples was determined in vitro method described by Luten (1996. Appropriate statistical technique was adopted for analysis of study.Result: Soya leaves, Radish leaves, Amaranth, Spinach were grown in both the areas except Kulpha and Karamwa, which are commonly grown in river side area. There was a significant difference between the bioavailability of iron and zinc in GLV grown in local and river side area.Conclusion: Hence it can be concluded that there is a contamination of heavy metals which binds with the iron and zinc and make them less bioavailable in the selected GLV.

  17. Quantification of the impact of macrophytes on oxygen dynamics and nitrogen retention in a vegetated lowland river

    NARCIS (Netherlands)

    Desmet, N.J.S.; Van Belleghem, S.; Seuntjens, P.; Bouma, T.J.; Buis, K.; Meire, P.

    2011-01-01

    When macrophytes are growing in the river, the vegetation induces substantial changes to the water quality. Some effects are the result of direct interactions, such as photosynthetic activity or nutrient uptake, whereas others may be attributed to indirect effects of the water plants on

  18. TOTAL COLUMN METHANE RETRIEVALS USING THE TROPOSPHERIC INFRARED MAPPING SPECTROMETER OVER SUNGLINT

    Directory of Open Access Journals (Sweden)

    N. Larsen

    2012-07-01

    Full Text Available Because it is a greenhouse gas, the detection of methane concentrations is a global issue. Additionally, the presence of methane is indicative of potential valuable petroleum and natural gas deposits. Therefore methane seep detection is useful for petroleum exploration around the world. The detection of methane, and other absorbing gases, over water is an issue for passive systems because one is seeking to detect an absorbing gas over an absorbing surface. The solution to this dilemma is to use the sun/sensor geometry for sun glint off of water to measure the absorbing gas over a reflecting surface, and therefore significantly increase the signal to noise of the measurement being taken. In September of 2010 Lockheed Martin performed a proof of concept by demonstrating from an airship over San Francisco Bay the capability of the Tropospheric Infrared Mapping Spectrometer's (TIMS hyper spectral sensor to passively measure methane, CO, and water vapor over sunglint water. The Lockheed Martin prototype TIMS sensor system is a hyper spectral grating spectrometer instrument that operates in the 2.3 micron spectral region at 0.25 cm-1 resolution. The Lockheed Martin retrieval algorithm developed applies the kCARTA (kCompressed Atmospheric Radiative Transfer Algorithm with Jacobians, with the HITRAN 2008 lineshape parameters, to retrieve the total column amount of atmospheric species along with the calibrated TIMS sensors radiometric input. A cell with known amount of methane was placed into the input to the TIMS to simulate atmospheric enhancements near the water surface. The amount in the cell was retrieved well within the uncertainty of 1% of the amount in the cell. Multi frame retrievals on data in which the cell was not placed into the input beam demonstrated 1% precision. In addition, in situ surface measurements were done over a landfill park, where measurements of methane were taken over known hotspots. This research allows for the future

  19. Comparison of Stream Restoration and Vegetation Restoration on Stream Temperature in the Middle Fork John Day River, Oregon

    Science.gov (United States)

    Diabat, M.; Wondzell, S. M.; Haggerty, R.

    2013-12-01

    Stream temperature is an important component of aquatic ecosystems. During the past century, various anthropogenic activities (such as timber harvest, mining, and agriculture) reduced riparian vegetation and channel complexity along many streams around the world. As a result, stream temperature increased and suitable habitat for cool- and cold-water organisms declined. Stream temperatures are expected to increase even more under future climate. The effects of warmer climate and anthropogenic activities are proposed to be mitigated by restoration projects aimed to reduce stream temperatures. Common restoration practices are replanting natural vegetation along stream banks and restoring channel complexity. The Middle Fork John Day River, in northeastern Oregon, USA is an example of such a process. We modeled stream temperature along a 37-km section of the Middle Fork John Day River for current and projected conditions of climate, restored riparian vegetation along 6.6-km, and restored channel meanders along 1.5 km. Preliminary simulations suggest that if current riparian vegetation remains unchanged, an average summertime air warming of 4°C increased the 7-day average daily maximum (7DADM) by about 1.3°C. However, restored riparian vegetation reduced the 7DADM by about 0.7°C relative to the current temperature. Restored channel meanders reduced the 7DADM by less than 0.05°C relative to the current temperature. These preliminary simulations assume no hyporheic exchange and riparian vegetation that is 10 m tall and has 30% canopy density.

  20. Mapping the spatio-temporal distribution of key vegetation cover properties in lowland river reaches, using digital photography.

    Science.gov (United States)

    Verschoren, Veerle; Schoelynck, Jonas; Buis, Kerst; Visser, Fleur; Meire, Patrick; Temmerman, Stijn

    2017-06-01

    The presence of vegetation in stream ecosystems is highly dynamic in both space and time. A digital photography technique is developed to map aquatic vegetation cover at species level, which has a very high spatial and a flexible temporal resolution. A digital single-lens reflex (DSLR) camera mounted on a handheld telescopic pole is used. The low-altitude (5 m) orthogonal aerial images have a low spectral resolution (red-green-blue), high spatial resolution (∼1.9 pixels cm(-2), ∼1.3 cm length) and flexible temporal resolution (monthly). The method is successfully applied in two lowland rivers to quantify four key properties of vegetated rivers: vegetation cover, patch size distribution, biomass and hydraulic resistance. The main advantages are that the method is (i) suitable for continuous and discontinuous vegetation covers, (ii) of very high spatial and flexible temporal resolution, (iii) relatively fast compared to conventional ground survey methods, (iv) non-destructive and (v) relatively cheap and easy to use, and (vi) the software is widely available and similar open source alternatives exist. The study area should be less than 10 m wide, and the prevailing light conditions and water turbidity levels should be sufficient to look into the water. Further improvements of the image processing are expected in the automatic delineation and classification of the vegetation patches.

  1. Seasonal divergence in the sensitivity of evapotranspiration to climate and vegetation growth in the Yellow River Basin, China

    Science.gov (United States)

    Pei, Tingting; Wu, Xiuchen; Li, Xiaoyan; Zhang, Yu; Shi, Fangzhong; Ma, Yujun; Wang, Pei; Zhang, Cicheng

    2017-01-01

    Seasonal variations in terrestrial evapotranspiration (ET) in the Yellow River Basin (YRB) have crucial impacts on the seasonal trajectories of the regional water cycle, vegetation growth, and local climate feedback. However, the possibly divergent roles of climate and vegetation growth variations in controlling seasonal ET patterns remain poorly quantified. This study therefore quantifies the interannual sensitivity and attribution of ET to climate and vegetation growth variations in different seasons and different biomes in the YRB in China between 1982 and 2011, using the satellite-derived normalized difference vegetation index (NDVI), FLUXNET-based upscaled ET, and concurrent climate data. The results reveal a clear seasonal divergence in the interannual sensitivity of ET to climate and vegetation growth variations in the YRB. Interannual precipitation and NDVI variations play a dominant role in controlling seasonal ET variations in the YRB, with temperature having a marginal effect. Interannual ET sensitivity to precipitation weakens with an increasing mean annual precipitation gradient in almost all seasons, especially in summer and autumn. More importantly, a seasonally varying role of vegetation growth in mediating seasonal ET was discovered, and a crucial role of late-growing-season vegetation growth in controlling the seasonal trajectory of regional ET was explicitly identified. These results suggest that ongoing intensive vegetation restoration has crucial impacts on seasonal water-cycle patterns and consequent terrestrial-atmospheric biogeochemical feedback in the YRB.

  2. Vegetation response to upstream water yield in the Heihe river by time series analysis of MODIS data

    Directory of Open Access Journals (Sweden)

    L. Jia

    2010-07-01

    Full Text Available Liquid and solid precipitation is abundant in the high elevation, upper reach of the Heihe basin. The development of modern irrigation schemes in the middle reach of the basin is taking up an increasing share of fresh water resources, endangering the oasis and traditional irrigation systems in the lower reach. In this study, the response of vegetation in the Ejina Oasis in the lower reach of the Heihe River to the water yield of the upper catchment was analyzed by time series analysis of monthly observations of precipitation in the upper and lower catchment, river streamflow downstream of the modern irrigation schemes and satellite observations of vegetation index. Firstly, remote sensing data were used to monitor the vegetation dynamic for a long time period. Due to cloud-contamination, atmospheric influence and different solar angles, however, the quality and consistence of time series of remote sensing data is degraded. In this research we used a Fourier Transform method – the Harmonic Analysis of Time Series (HANTS algorithm – to reconstruct cloud-free NDVI time series data from the Terra-MODIS dataset. Anomalies in precipitation, streamflow, and vegetation index are detected by comparing each year with the average year. The relationship between the anomalies in vegetation growth, the local precipitation and upstream water yield were analyzed. The same approach is used to identify, remove and gap-filling cloud contaminated observations in the satellite data for each year in the dataset. The results showed that: the previous year total runoff had a significant relationship with the vegetation growth in Ejina Oasis and that anomalies in monthly runoff of the Heihe River influenced the phenology of vegetation in the entire oasis during drier years. The time of maximum green-up was uniform throughout the oasis during wetter years, but showed a clear S–N gradient (downstream during drier years.

  3. Vegetation

    DEFF Research Database (Denmark)

    Epstein, H.E.; Walker, D.A.; Bhatt, U.S.

    2012-01-01

    increased 20-26%. • Increasing shrub growth and range extension throughout the Low Arctic are related to winter and early growing season temperature increases. Growth of other tundra plant types, including graminoids and forbs, is increasing, while growth of mosses and lichens is decreasing. • Increases...... in vegetation (including shrub tundra expansion) and thunderstorm activity, each a result of Arctic warming, have created conditions that favor a more active Arctic fire regime....

  4. Phenological response of vegetation to upstream river flow in the Heihe Rive basin by time series analysis of MODIS data

    Directory of Open Access Journals (Sweden)

    L. Jia

    2011-03-01

    Full Text Available Liquid and solid precipitation is abundant in the high elevation, upper reach of the Heihe River basin in northwestern China. The development of modern irrigation schemes in the middle reach of the basin is taking up an increasing share of fresh water resources, endangering the oasis and traditional irrigation systems in the lower reach. In this study, the response of vegetation in the Ejina Oasis in the lower reach of the Heihe River to the water yield of the upper catchment was analyzed by time series analysis of monthly observations of precipitation in the upper and lower catchment, river streamflow downstream of the modern irrigation schemes and satellite observations of vegetation index. Firstly, remotely sensed NDVI data acquired by Terra-MODIS are used to monitor the vegetation dynamic for a seven years period between 2000 and 2006. Due to cloud-contamination, atmospheric influence and different solar and viewing angles, however, the quality and consistence of time series of remotely sensed NDVI data are degraded. A Fourier Transform method – the Harmonic Analysis of Time Series (HANTS algorithm – is used to reconstruct cloud- and noise-free NDVI time series data from the Terra-MODIS NDVI dataset. Modification is made on HANTS by adding additional parameters to deal with large data gaps in yearly time series in combination with a Temporal-Similarity-Statistics (TSS method developed in this study to seek for initial values for the large gap periods. Secondly, the same Fourier Transform method is used to model time series of the vegetation phenology. The reconstructed cloud-free NDVI time series data are used to study the relationship between the water availability (i.e. the local precipitation and upstream water yield and the evolution of vegetation conditions in Ejina Oasis from 2000 to 2006. Anomalies in precipitation, streamflow, and vegetation index are detected by comparing each year with the average year. The results showed that

  5. Oral bioaccessibility and human exposure assessment of cadmium and lead in market vegetables in the Pearl River Delta, South China.

    Science.gov (United States)

    Zhuang, Ping; Li, Yingwen; Zou, Bi; Su, Feng; Zhang, Chaosheng; Mo, Hui; Li, Zhian

    2016-12-01

    A systematic investigation into cadmium (Cd) and lead (Pb) concentrations and their oral bioaccessibility in market vegetables in the Pearl River Delta region were carried out to assess their potential health risks to local residents. The average concentrations of Cd and Pb in six species of fresh vegetables varied within 0.09-37.7 and 2.3-43.4 μg kg(-1), respectively. Cadmium and Pb bioaccessibility were 35-66 % and 20-51 % in the raw vegetables, respectively, and found to be significantly higher than the cooked vegetables with 34-64 % for Cd and 11-48 % for Pb. The results indicated that Cd bioaccessibility was higher in the gastric phase and Pb bioaccessibility was higher in the small intestinal phase (except for fruit vegetables). Cooking slightly reduced the total concentrations and bioaccessibility of Cd and Pb in all vegetables. The bioaccessible estimated daily intakes of Cd and Pb from vegetables were far below the tolerable limits.

  6. [Change of vegetation net primary productivity in Yellow River watersheds from 2001 to 2010 and its climatic driving factors analysis].

    Science.gov (United States)

    Chen, Qiang; Chen, Yun-Hao; Wang, Meng-Jie; Jiang, Wei-Guo; Hou, Peng; Li, Ying

    2014-10-01

    Based on the MODIS-NDVI remotely sensed imagery, this paper analyzed the spatial distribution of vegetation net primary production (NPP) calculated by CASA model in Yellow River watersheds from 2001 to 2010. Associated with the temperature and precipitation data in the same period, this article respectively analyzed the change trends of vegetation NPP in six ecosystems with different spatial and temporal scales, and the relationship between NPP and climate factors. The results indicated that in terms of spatial scale, the vegetation NPP gradually reduced from northwest to southeast, the average of annual NPP was 108.53 Tg C, and the spatial distribution of vegetation NPP was highly related with the land cover types. In terms of temporal scale, the vegetation NPP gradually increased from 2001 to 2010, but this change trend had large differences in these regions. On annual level, the vegetation NPP had no significant correlation with climate factors, but precipitation and temperature had considerable impacts on the vegetation NPP on monthly level. The correlations between NPP and climate factors were different in different ecosystems, so did the time lag effect of the climate factors. The air temperature response of the NPP variation was relatively sensitive in forest ecosystem and the precipitation response was significant in grassland and wetland ecosystems. Additionally, the precipitation response of the NPP variation in grassland ecosystem had time lag effect and so did the air temperature response in desert ecosystem.

  7. C3 Vegetation Mapping and CO2 Fertilization Effect in the Arid Lower Heihe River Basin, Northwestern China

    Directory of Open Access Journals (Sweden)

    Yunbo Bi

    2015-12-01

    Full Text Available In arid regions, C3 vegetation is assumed to be more sensitive to precipitation and CO2 fertilization than C4 vegetation. In this study, normalized difference vegetation index (NDVI is used to examine vegetation growth in the arid Lower Heihe River Basin, northwestern China, for the past three decades. The results indicate that maximum NDVI (MNDVI of the area increases over the years and is significantly correlated with precipitation (R = 0.47 and p < 0.01, not temperature (R = −0.04. The upper limit of C3 vegetation cover of the area shows a yearly rising trend of 0.6% or an overall increase of 9% over the period of 25 years, primarily due to the CO2 fertilization effect (CO2 rising 14% over the same period. C3 dominant areas can be potentially distinguished by both MNDVI asynchronous seasonality and a significant relation between MNDVI and cumulative precipitation. This study provides a potential tool of identifying C3 vegetation from C4 vegetation and confirms the CO2 fertilization effect in this arid region.

  8. Floodplain Sedimentation in Vegetated Areas of the Elwha River Floodplain, 2012-2014

    Science.gov (United States)

    Lauer, J. W.; Polka, J.

    2014-12-01

    The removal of the Elwha and Glines Canyon Dams from the Elwha River, near Port Angeles, Washington, has released a large pulse of sediment into the middle and lower reaches of the Elwha River. This sediment has important geomorphic, hydraulic, and ecological implications. Our project focuses on the deposition of fine sediment on vegetated parts of the Elwha floodplain using field observations of sediment accumulation in combination with a simplified physics numerical model, CAESAR-Lisflood. The floodplain of the Elwha is densely vegetated and in places is characterized by large amounts of local topographic variation. This makes measuring centimeter-scale overbank sedimentation difficult using traditional approaches such as lidar and total-station based cross-section surveys. To address this problem and to provide ground truth for more traditional surveying methods, we set up over 50 short (10-20 m long) cross-sections between sets of flagged trees and surveyed, at 1-meter intervals, ground elevation with respect to a spike set in each section. Nails in the trees ensure that the horizontal position of our measurements do not shift by more than a few centimeters from year to year. This approach allows sediment accumulation to be measured repeatedly with a precision we estimate to be on the order of a few centimeters, allowing us to estimate annual rates of local sedimentation. At a given point on the floodplain, sedimentation should depend significantly on the frequency of inundation. We simulate this for the 2012-2014 period using a CAESAR-Lisflood 2-D numerical model calibrated using a set of continuously recording staff gages. CAESAR-Lisflood uses simplified-physics hydraulic routines to efficiently simulate flow depth and velocity and to drive size-specific sediment transport and morphodynamic change. This allows the model to simulate changes in flood inundation probability for the post- removal period. CAESAR-based hydraulic results are used to interpret our

  9. Vegetative impacts upon bedload transport capacity and channel stability for differing alluvial planforms in the Yellow River source zone

    Science.gov (United States)

    Li, Zhi Wei; Yu, Guo An; Brierley, Gary; Wang, Zhao Yin

    2016-07-01

    The influence of vegetation upon bedload transport and channel morphodynamics is examined along a channel stability gradient ranging from meandering to anabranching to anabranching-braided to fully braided planform conditions along trunk and tributary reaches of the Upper Yellow River in western China. Although the regional geology and climate are relatively consistent across the study area, there is a distinct gradient in the presence and abundance of riparian vegetation for these reaches atop the Qinghai-Tibet Plateau (elevations in the study area range from 2800 to 3400 m a.s.l.). To date, the influence of vegetative impacts upon channel planform and bedload transport capacity of alluvial reaches of the Upper Yellow River remains unclear because of a lack of hydrological and field data. In this region, the types and pattern of riparian vegetation vary with planform type as follows: trees exert the strongest influence in the anabranching reach, the meandering reach flows through meadow vegetation, the anabranching-braided reach has a grass, herb, and sparse shrub cover, and the braided reach has no riparian vegetation. A non-linear relation between vegetative cover on the valley floor and bedload transport capacity is evident, wherein bedload transport capacity is the highest for the anabranching reach, roughly followed by the anabranching-braided, braided, and meandering reaches. The relationship between the bedload transport capacity of a reach and sediment supply from upstream exerts a significant influence upon channel stability. Bedload transport capacity during the flood season (June-September) in the braided reach is much less than the rate of sediment supply, inducing bed aggradation and dynamic channel adjustments. Rates of channel adjustment are less pronounced for the anabranching-braided and anabranching reaches, while the meandering reach is relatively stable (i.e., this is a passive meandering reach).

  10. Flow recommendations for maintaining riparian vegetation along the Upper Missouri River, Montana

    Science.gov (United States)

    Scott, Michael L.; Auble, Gregor T.; Friedman, Jonathan M.; Ischinger, Lee S.; Eggleston, Erik D.; Wondzell, Mark A.; Shafroth, Patrick B.; Back, Jennifer T.; Jordan, Mette S.

    1993-01-01

    Montana Power Company, Inc. (MPC) submitted a final license application to the Federal Energy Regulatory Commission (FERC) on November 30, 1992. In this application, MPC proposed a plan for the protection of fish, wildlife, habitat, and water-quality resources. One concern was maintenance of woody riparian vegetation along the Missouri River, especially along the Wild and Scenic reach of the river, where the riparian forest occurs in relatively small discontinuous stands. The objectives of this project were 1) to recommend flows that would protect and enhance riparian forests along the Missouri River, and 2) to develop elements of an environmental monitoring program that could be used to assess the effectiveness of the recommended flows. Plains cottonwood (Populus deltoides subsp. monilifera) is the key structural component of riparian forests along the Missouri River. Therefore, we focused our analysis on factors affecting populations of this species. Previous work had demonstrated that the age structure of cottonwood populations is strongly influenced by aspects of flow that promote successfully establishment. In this study our approach was to determine the precise age of plains cottonwood trees growing along the Upper Missouri River and to relate years of establishment to the flow record. Our work was carried out between Coal Banks Landing and the Fred G. Robinson Bridge within the Wild and Scenic portion of the Missouri River. This segment of the river occupies a narrow valley and exhibits little channel migration. Maps and notes from the journals of Lewis and Clark (1804-1806) suggest that the present distribution and abundance of cottonwoods within the study reach is generally similar to presettlement conditions. Flows in the study reach are influenced by a number of dams and diversions, most importantly, Canyon Ferry and Tiber Dams. Although flow regulation has decreased peak flows and increased low flows, the gross seasonal pattern of flow has not been

  11. Long-term channel adjustment and geomorphic feature creation by vegetation in a lowland, low energy river

    Science.gov (United States)

    Grabowski, Robert; Gurnell, Angela

    2016-04-01

    Physical habitat restoration is increasingly being used to improve the ecological status of rivers. This is particularly true for lowland streams which are perceived to lack sufficient energy to create new features or to flush out fine sediment derived from agricultural and urban sources. However, this study has found that even in low-energy, base-flow dominated chalk streams, physical habitat improvement can happen naturally without direct human intervention. Furthermore this positive change is achieved by components of the river that are often regarded as management problems: in-stream macrophytes (i.e. weed), riparian trees, woody debris, and most importantly fine sediment. This project investigated the long-term changes in channel planform for the River Frome (Dorset, UK) over the last 120 years and the role of aquatic and riparian vegetation in driving this change. Agricultural census data, historical maps, recent aerial images and field observations were analysed within a process-based, hierarchical framework for hydromorphological assessment, developed in the EU FP7 REFORM project, to investigate the source and timing of fine sediment production in the catchment, to quantify the reach-scale geomorphic response, and to identify vegetation-related bedforms that could be responsible for the adjustment. The analysis reveals that the channel has narrowed and become more sinuous in the last 50-60 years. The timing of this planform adjustment correlates with substantial changes in land use and agricultural practices (post-World War II) that are known to increase soil erosion and sediment connectivity. The field observations and recent aerial images suggest that the increased delivery of fine sediment to the channel has been translated into geomorphic adjustment and diversification though the interactions between vegetation, water flow and sediment. Emergent aquatic macrophytes are retaining fine sediment, leading to the development of submerged shelves that aggrade

  12. Vegetation Cover Change in the Upper Kings River Basin of the Sierra Nevada Detected Using Landsat Satellite Image Analysis

    Science.gov (United States)

    Potter, Christopher S.

    2015-01-01

    The Sierra Nevada of California is a region where large wildfires have been suppressed for over a century. A detailed geographic record of recent changes in vegetation cover across the Sierra Nevada remains a gap that can be filled with satellite remote sensing data. Results from Landsat image analysis over the past 25 years in the Upper Kings River basin showed that consistent, significant increases in the normalized difference vegetation index (NDVI) have not extended above 2000 m elevation, where cold temperatures presumably limit the growing season. Moreover, mean increases in NDVI since 1986 at elevations below 2000 m (which cover about half of the total basin area) have not exceeded 9%, even in the most extreme precipitation yearly comparisons. NDVI has decreased significantly at elevations above 2000 m throughout the basin in relatively wet year comparisons since the mid-1980s. These findings conflict with any assumptions that ET fluxes and river flows downstream could have been markedly altered by vegetation change over most of the Upper Kings River basin in recent decades.

  13. Elevation-Dependent Vegetation Greening of the Yarlung Zangbo River Basin in the Southern Tibetan Plateau, 1999–2013

    Directory of Open Access Journals (Sweden)

    Haidong Li

    2015-12-01

    Full Text Available The Yarlung Zangbo River basin is an important alley to transport moisture from the Indian Ocean to the inner Tibetan Plateau. With a wide range of elevations from 147 m to over 7000 m above sea level (a.s.l., ecosystems respond differently to climate change at various elevations. However, the pattern of elevation-dependent vegetation change and how it responds to recent warming have been rarely reported. Here, we investigated the pattern of vegetation greening at different elevations in this river basin using SPOT normalized difference vegetation index (NDVI data during 1999–2013, and examined its relationship with elevation-dependent changes in temperature and precipitation. The annual NDVI has increased by 8.83% from 1999 to 2013. In particular, the NDVI increased more apparently at lower elevations, but remained relatively stable or even decreased at high elevations. It seems that rising temperature has driven the basin-wide vegetation greening, but the greening rate is in contrast to the pattern of elevation-dependent warming (EDW with more significant temperature increase at higher elevations. It appears that decreasing precipitation does not reverse the overall increasing trend in NDVI, but relatively limited precipitation (<500 mm may constrain the NDVI increases, causing apparently stable or even decreased NDVI at higher elevations (>4000 m.

  14. Restored river corridors: first results on the effects of flow variability on vegetation cuttings survival rate and related root architecture

    Science.gov (United States)

    Pasquale, N.; Perona, P.; Jiang, Z.; Burlando, P.

    2009-04-01

    Understanding and predicting the evolution of river alluvial bed forms toward a vegetated or a non-vegetated morphology have important implications for restored river corridors and the related ecosystem functioning (see also Schäppi et al, this session). Vegetation recruitment and growth on non-cohesive material of river corridors, such as gravel bars and islands of braided river, depend on the ability of roots to develop and anchor efficiently such to resist against flow erosion. In this work, we study the interannual morphological evolution of a gravel bar island, the survival rate and the growth of a number of plots with different density and orientation of transplanted cuttings (Salix Alba), the space and time dynamics of which depend on erosion and deposition processes due to floods. Our purpose is to identify island locations where the hydrodynamic conditions are more suitable for plants germination, growth and survival in relation to the river hydrograph statistics. This information is a first step to build a stochastic model able to predict the future evolution and progress of the restoration action of the investigated river reach. We focus at the main island of River Thur at Niederneunforn (Canton Thurgau, Switzerland), the restoration success of which is investigated from a mechanistic viewpoint in the research project "REstored CORridor Dynamics" (www.record.ethz.ch). Accordingly, we analyze two recent Digital Elevation Models (1 year difference), which were first corrected to account for the river bathymetry, and then we compare them in order to extract relevant interannual morphological changes. Using a two dimensional numerical hydrodynamic model we simulate several flow conditions ranging from the minimum recorded flow up to the one that completely inundates the island. Hence, we build inundation maps of the island that we associate to the frequency and the submergence duration of every area. We then correlate such results to the observed survival

  15. Responses of Vegetation Growth to Climatic Factors in Shule River Basin in Northwest China: A Panel Analysis

    Directory of Open Access Journals (Sweden)

    Jinghui Qi

    2017-03-01

    Full Text Available The vegetation response to climatic factors is a hot topic in global change research. However, research on vegetation in Shule River Basin, which is a typical arid region in northwest China, is still limited, especially at micro scale. On the basis of Moderate-resolution Imaging Spectroradiometer (MODIS Normalized Difference Vegetation Index (NDVI data and daily meteorological data, employing panel data models and other mathematical models, the aim of this paper is to reveal the interactive relationship between vegetation variation and climatic factors in Shule River Basin. Results show that there is a widespread greening trend in the whole basin during 2000–2015, and 80.28% of greening areas (areas with vegetation improvement are distributed over upstream region, but the maximum vegetation variation appears in downstream area. The effects of climate change on NDVI lag about half to one month. The parameters estimated using panel data models indicate that precipitation and accumulated temperature have positive contribution to NDVI. With every 1-mm increase in rainfall, NDVI increases by around 0.223‰ in upstream area and 0.6‰ in downstream area. With every 1-°C increase in accumulated temperature, NDVI increases by around 0.241‰ in upstream area and 0.174‰ in downstream area. Responses of NDVI to climatic factors are more sensitive when these factors are limiting than when they are not limiting. NDVI variation has performance in two seasonal and inter-annual directions, and the range of seasonal change is far more than that of inter-annual change. The inverted U-shaped curve of the variable intercepts reflects the seasonal change. Our results might provide some scientific basis for the comprehensive basin management.

  16. Understanding the Physiography, Bioclimate and Mapping of the Vegetation of the Chalakkudy River Basin, Anamalai part of Southern Western Ghats, India

    Directory of Open Access Journals (Sweden)

    Amitha Bachan Kandarumadathil Hyder

    2014-09-01

    Full Text Available Vegetation of an area is determined by the overall interaction of the climatic, edaphic, and biotic factors. It is important to define the bioclimate of a region to understand the Vegetation dynamics of a region especially of the Tropical Monsoonal continents with complex physiography. It is a pioneering effort to understand bioclimate and primary   vegetation of a river basin from the southern Western Ghats region. Twenty years of rainfall data were analysed and geophysical features of the Chalakkudy River basin were analysed using GIS facility. The results provide more accurate data of the length, area and other physiographic features for the Chalakkudy River basin indicating need of updating of data of other river basins of Kerala. The bioclimatic data analyzed from 20 years of rainfall and vegetation maps indicate presence of dry-moist-forest zones to ever wet-rainforest regimes in the basin. The vegetation data shows 80% catchements of the river under forest category of which primary forests dominates with 519 Km2 (36% followed by forest plantations 179.6 Km2 (12%, secondary forests 197.4 Km2 (17%, tea, coffee and other plantations constitute 198.3 Km2 (13%, degraded non forest vegetation 86.9 Km2 (6% and reservoir, streams and rivers 46.5 Km2 (3%.  Of the 361 Km2 primary wet-evergreen (Rainforests forests 294 Km2 is dense forest and 67 Km2 is degraded forests.

  17. The influence of vegetal cover on carbon assimilation by Prochilodus lineatus (Characiformes: Prochilodontidae in the upper Paraná river floodplain

    Directory of Open Access Journals (Sweden)

    Mariana Cristina Serragiotto

    2014-08-01

    Full Text Available The present study examined the influence of the availability of riparian vegetation and C3 emergent aquatic macrophytes on carbon assimilation by Prochilodus lineatus. The vegetal cover of these producers, available at 30 m of the bank, for the terrestrial ecosystem of the rivers Baia, Ivinheima and Paraná, was quantified with the image processing Landsat 5 TM, of the year 2000, period of sampling of the biological material at each river. The assimilation of the energy sources (riparian vegetation and C3 aquatic macrophytes, C4 aquatic macrophytes, periphyton, and phytoplankton by P. lineatus was determined by analysis of stable carbon isotopes (δ13C. The area of vegetal cover was estimated at 1,017 km2 in the Ivinheima river, 669 km2 in the Paraná river, and 268 km2 in the Baia river. The assimilation of the carbon from riparian vegetation and aquatic macrophytes was proportional to the availability in the environment, but these producers were not the main source of carbon for P. lineatus. Thus, in the rivers with greater vegetation cover, consequently, these items had higher availability in the water body becoming an important carbon source for the species maintenance.

  18. Limiting the development of riparian vegetation in the Isère River: physical and numerical modelling study

    Science.gov (United States)

    Claude, Nicolas; El Kadi Abderrezzak, Kamal; Duclercq, Marion; Tassi, Pablo; Leroux, Clément

    2017-04-01

    The Isère River (France) has been strongly impacted during the 19th and 20th centuries by human activities, such as channelization, sediment dredging and damming. The hydrology and river morphodynamic have been significantly altered, thereby leading to riverbed incision, a decrease in submersion frequency of gravel bars and an intense development of riparian vegetation on the bars. The flood risk has increased due to the reduction of the flow conveyance of the river, and the ecological status of the river has been degraded. To face these issues, a research program involving EDF and French state authorities has been recently initiated. Modification of the current hydrology, mainly controlled by dams, and definition of a new bed cross-sectional profile, are expected to foster the submersion frequency and mobility of the bars, thus limiting the riparian development. To assess the performance of these mitigating solutions, a physical and numerical modelling study has been conducted, applied to a 2 km long reach of the Isère River. The experimental setup consists of an undistorted movable bed designed to ensure the similarity of the Froude number and initial conditions for sediment particle motion. The resulting physical model is 35 m long and 2.6 m wide, with sand mixture composed of three grain size classes. The numerical simulations performed with the Telemac Modelling System (www.opentelemac.org) show, for the current morphology, a limited sediment mobility and submersion for flow discharge lower than 400 m3/s, confirming that the actual conditions in the Isère River promote the development of riparian vegetation. Different new bed geometry profiles have been evaluated using the numerical model. Then two configurations, one based on the creation of deflecting bedforms in the thalweg and one based on the transformation of the long bars into small central bars, have been selected and modelled with the physical model.

  19. Vegetation response to invasive Tamarix control in southwestern U.S. rivers: A collaborative study including 416 sites

    Science.gov (United States)

    González, Eduardo; Sher, Anna A; Anderson, Robert M.; Bay, Robin F.; Bean, Daniel W.; Bissonnete, Gabriel J.; Bourgeois, Bérenger; Cooper, David J.; Dohrenwend, Kara; Eichhorst, Kim D.; El Waer, Hisham; Kennard, Deborah K.; Harms-Weissinger, Rebecca; Henry, Annie L.; Makarick, Lori J.; Ostoja, Steven M.; Reynolds, Lindsay V.; Robinson, W. Wright; Shafroth, Patrick B.

    2017-01-01

    Most studies assessing vegetation response following control of invasive Tamarix trees along southwestern U.S. rivers have been small in scale (e.g., river reach), or at a regional scale but with poor spatial-temporal replication, and most have not included testing the effects of a now widely used biological control. We monitored plant composition following Tamarix control along hydrologic, soil, and climatic gradients in 244 treated and 172 reference sites across six U.S. states. This represents the largest comprehensive assessment to date on the vegetation response to the four most common Tamarix control treatments. Biocontrol by a defoliating beetle (treatment 1) reduced the abundance of Tamarix less than active removal by mechanically using hand and chain-saws (2), heavy machinery (3) or burning (4). Tamarix abundance also decreased with lower temperatures, higher precipitation, and follow-up treatments for Tamarix resprouting. Native cover generally increased over time in active Tamarix removal sites, however, the increases observed were small and was not consistently increased by active revegetation. Overall, native cover was correlated to permanent stream flow, lower grazing pressure, lower soil salinity and temperatures, and higher precipitation. Species diversity also increased where Tamarix was removed. However, Tamarix treatments, especially those generating the highest disturbance (burning and heavy machinery), also often promoted secondary invasions of exotic forbs. The abundance of hydrophytic species was much lower in treated than in reference sites, suggesting that management of southwestern U.S. rivers has focused too much on weed control, overlooking restoration of fluvial processes that provide habitat for hydrophytic and floodplain vegetation. These results can help inform future management of Tamarix-infested rivers to restore hydrogeomorphic processes, increase native biodiversity and reduce abundance of noxious species.

  20. Effects of coal-bed methane discharge waters on the vegetation and soil ecosystem in Powder River Basin, Wyoming

    Science.gov (United States)

    Stearns, M.; Tindall, J.A.; Cronin, G.; Friedel, M.J.; Bergquist, E.

    2005-01-01

    Coal-bed methane (CBM) co-produced discharge waters in the Powder River Basin of Wyoming, resulting from extraction of methane from coal seams, have become a priority for chemical, hydrological and biological research during the last few years. Soil and vegetation samples were taken from affected and reference sites (upland elevations and wetted gully) in Juniper Draw to investigate the effects of CBM discharge waters on soil physical and chemical properties and on native and introduced vegetation density and diversity. Results indicate an increase of salinity and sodicity within local soil ecosystems at sites directly exposed to CBM discharge waters. Elevated concentrations of sodium in the soil are correlated with consistent exposure to CBM waters. Clay-loam soils in the study area have a much larger specific surface area than the sandy soils and facilitate a greater sodium adsorption. However, there was no significant relation between increasing water sodium adsorption ratio (SAR) values and increasing sediment SAR values downstream; however, soils exposed to the CBM water ranged from the moderate to severe SAR hazard index. Native vegetation species density was highest at the reference (upland and gully) and CBM affected upland sites. The affected gully had the greatest percent composition of introduced vegetation species. Salt-tolerant species had the greatest richness at the affected gully, implying a potential threat of invasion and competition to established native vegetation. These findings suggest that CBM waters could affect agricultural production operations and long-term water quality. ?? Springer 2005.

  1. A study on the relationship between vegetation pattern and environment in the upstream of Minjiang River,China

    Institute of Scientific and Technical Information of China (English)

    Li Chongwei; Lin Yong; Liu Lijuan; Ge Jianping

    2006-01-01

    The vegetation pattern in the upstream of Minjiang River,and its relationship with environment factors,such as landscape position(elevation,slope,aspect),precipitation and temperature and soil are analyzed in this paper.The data used in this Paper were based on the landscape map derived from 1994 TM imagery.The results were as follows:1)dominant landscape types were forest,shrub land and grassland,which were very similar in terms of area ratio(32.87%,31.85% and 28.44%,respectively);2)the patch shape of conifer forest and mixed forest was complicated while that of broad-leaved forest and cultivated land was simple;3)the fragmentation of conifer forest and mixed forest was serious in contrast with low fragmentation of broad-leaved forest and cultivated land;and 4)closed scrub and grassland had a high contagion and good connectivity while mixed forest had a lower contagion and bad connectivity.In addition,the vegetation distribution pattern of upstream of Minjiang River Was closely related with elevation and temperature,but the relationship between vegetation and precipitation was not statistically significant.

  2. Remapping annual precipitation in mountainous areas based on vegetation patterns: a case study in the Nu River basin

    Science.gov (United States)

    Zhou, Xing; Ni, Guang-Heng; Shen, Chen; Sun, Ting

    2017-02-01

    Accurate high-resolution estimates of precipitation are vital to improving the understanding of basin-scale hydrology in mountainous areas. The traditional interpolation methods or satellite-based remote sensing products are known to have limitations in capturing the spatial variability of precipitation in mountainous areas. In this study, we develop a fusion framework to improve the annual precipitation estimation in mountainous areas by jointly utilizing the satellite-based precipitation, gauge measured precipitation, and vegetation index. The development consists of vegetation data merging, vegetation response establishment, and precipitation remapping. The framework is then applied to the mountainous areas of the Nu River basin for precipitation estimation. The results demonstrate the reliability of the framework in reproducing the high-resolution precipitation regime and capturing its high spatial variability in the Nu River basin. In addition, the framework can significantly reduce the errors in precipitation estimates as compared with the inverse distance weighted (IDW) method and the TRMM (Tropical Rainfall Measuring Mission) precipitation product.

  3. Holocene ethnobotanical and paleoecological record of human impact on vegetation in the Little Tennessee River Valley, Tennessee

    Science.gov (United States)

    Delcourt, Paul A.; Delcourt, Hazel R.; Cridlebaugh, Patricia A.; Chapman, Jefferson

    1986-05-01

    Human occupation and utilization of plant resources have affected vegetation in the lower Little Tennessee River Valley of East Tennessee for 10,000 yr. Changes in Indian cultures and land use are documented by radiocarbon chronologies, lithic artifacts, ceramics, settlement patterns, and ethnobotanical remains from 25 stratified archaeological sites within the Holocene alluvial terrace. The ethnobotanical record consists of 31,500 fragments (13.7 kg) of wood charcoal identified to species and 7.7 kg of carbonized fruits, seeds, nutshells, and cultigens from 956 features. Pollen and plant macrofossils from small ponds both in the uplands and on lower stream terraces record local vegetational changes through the last 1500 to 3000 yr. Human impact increased after cultigens, including squash and gourd, were introduced ca. 4000 yr B.P. during the Archaic cultural period. Forest clearance and cultivation disturbed vegetation on both the floodplain and lower terraces after 2800 yr B.P., during the Woodland period. Permanent Indian settlements and maize and bean agriculture extended to higher terraces 1.5 km from the floodplain by the Mississippian period (1000 to 300 yr B.P.). After 300 yr B.P., extensive land clearance and cultivation by Historic Overhill Cherokee and Euro-Americans spread into the uplands beyond the river valley.

  4. Observation Points for Knife River Indian Villages National Historic Site Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — These points represent vegetation association types collected within KNRI boundaries in August 2002. Items include Formation Class through Association.

  5. Estimates of deep percolation beneath native vegetation, irrigated fields, and the Amargosa-River Channel, Amargosa Desert, Nye County, Nevada

    Science.gov (United States)

    Stonestrom, David A.; Prudic, David E.; Laczniak, Randell J.; Akstin, Katherine C.; Boyd, Robert A.; Henkelman, Katherine K.

    2003-01-01

    The presence and approximate rates of deep percolation beneath areas of native vegetation, irrigated fields, and the Amargosa-River channel in the Amargosa Desert of southern Nevada were evaluated using the chloride mass-balance method and inferred downward velocities of chloride and nitrate peaks. Estimates of deep-percolation rates in the Amargosa Desert are needed for the analysis of regional ground-water flow and transport. An understanding of regional flow patterns is important because ground water originating on the Nevada Test Site may pass through the area before discharging from springs at lower elevations in the Amargosa Desert and in Death Valley. Nine boreholes 10 to 16 meters deep were cored nearly continuously using a hollow-stem auger designed for gravelly sediments. Two boreholes were drilled in each of three irrigated fields in the Amargosa-Farms area, two in the Amargosa-River channel, and one in an undisturbed area of native vegetation. Data from previously cored boreholes beneath undisturbed, native vegetation were compared with the new data to further assess deep percolation under current climatic conditions and provide information on spatial variability. The profiles beneath native vegetation were characterized by large amounts of accumulated chloride just below the root zone with almost no further accumulation at greater depths. This pattern is typical of profiles beneath interfluvial areas in arid alluvial basins of the southwestern United States, where salts have been accumulating since the end of the Pleistocene. The profiles beneath irrigated fields and the Amargosa-River channel contained more than twice the volume of water compared to profiles beneath native vegetation, consistent with active deep percolation beneath these sites. Chloride profiles beneath two older fields (cultivated since the 1960?s) as well as the upstream Amargosa-River site were indicative of long-term, quasi-steady deep percolation. Chloride profiles beneath the

  6. Potential effects of four Flaming Gorge Dam hydropower operational scenarios on riparian vegetation of the Green River, Utah and Colorado

    Energy Technology Data Exchange (ETDEWEB)

    LaGory, K.E.; Van Lonkhuyzen, R.A. [Argonne National Lab., IL (United States). Ecological Sciences Section

    1995-06-01

    Four hydropower operational scenarios at Flaming Gorge Dam were evaluated to determine their potential effects on riparian vegetation along the Green River in Utah and Colorado. Data collected in June 1992 indicated that elevation above the river had the largest influence on plant distribution. A lower riparian zone occupied the area between the approximate elevations of 800 and 4,200-cfs flows--the area within the range of hydropower operational releases. The lower zone was dominated by wetland plants such as cattail, common spikerush, coyote willow, juncus, and carex. An upper riparian zone was above the elevation of historical maximum power plant releases from the dam (4,200 cfs), and it generally supported plants adapted to mesic, nonwetland conditions. Common species in the upper zone included box elder, rabbitbrush, grasses, golden aster, and scouring rush. Multispectral aerial videography of the Green River was collected in May and June 1992 to determine the relationship between flow and the areas of water and the riparian zone. From these relationships, it was estimated that the upper zone would decrease in extent by about 5% with year-round high fluctuation, seasonally adjusted high fluctuation, and seasonally adjusted moderate fluctuation, but it would increase by about 8% under seasonally adjusted steady flow. The lower zone would increase by about 13% for both year-round and seasonally adjusted high fluctuation scenarios but would decrease by about 40% and 74% for seasonally adjusted moderate fluctuation and steady flows, respectively. These changes are considered to be relatively minor and would leave pre-dam riparian vegetation unaffected. Occasional high releases above power plant capacity would be needed for long-term maintenance of this relict vegetation.

  7. Vegetation establishment success in restored carolina bay depressions on the Savannah River Site, South Carolina - phase one.

    Energy Technology Data Exchange (ETDEWEB)

    Sharitz, Rebecca, A.; Mulhouse, John, M.

    2004-05-01

    Successful wetlands restoration must re-establish or enhance three parameters: wetland hydrology, hydric soils, and hydrophytic vegetation (Mitsch and Gosselink 2000). On the Savannah River Site, South Carolina, restoration of small Carolina bay depression-wetlands was initiated in FY 2001 to provide wetland acreage for mitigation banking (US DOE 1997). Sixteen small depressions that had historically been drained for agricultural purposes were selected for restoration, and an additional four were initially chosen to serve as non-restored controls. Restoration treatments included plugging the existing ditches to increase water volume retention and wetland hydroperiod and clear-cutting removal of woody vegetation in the interiors. Planned endpoints of the restoration were herbaceous meadow and forested savanna bay interiors, and pine savanna and pine/hardwood forested bay margins (Barton and Singer 2001). To promote forested savanna interiors, saplings of bald cypress and swamp tupelo were planted following removal of the woody species.

  8. Vegetation Dynamics and Its Response to Climate Change - A Case Study from Gandaki River Basin in Central Nepal

    Science.gov (United States)

    Panthi, J., Sr.

    2016-12-01

    Vegetation is affected by inter-annual variability and trends in precipitation, temperature, and snow cover. Remote sensing is especially important for monitoring vegetation response in mountainous regions like the Himalayas in subtropical Asia, where few detailed field investigations of ecosystem variability have been performed due to logistical challenges. We compared MODIS Normalized Difference Vegetation Index (NDVI) in the Gandaki River Basin (GRB) in central Nepal to mean climate and its interannual variability and trends to quantify these relationships over a steep elevation gradient. NDVI was found to be highest in the lower and middle elevations and sharply decrease past 3000 m asl. Seasonally, NDVI peaks in the fall (post-monsoon season) followed by summer (monsoon season), indicating a positive response of vegetation to the rainfall peak. Inter-annual variability in climate, particularly temperature, is correlated with NDVI fluctuations in the basin. When the GRB is disaggregated by land cover, NDVI is most closely related to temperature and precipitation in agricultural areas, followed by grasslands. Snow cover in the GRB is decreasing but does not show any relationship with basin-wide NDVI.

  9. Remote sensing analysis of desert vegetation and its landscape changes: The case in middle reaches of Tarim River Basin, Xinjiang, China

    Institute of Scientific and Technical Information of China (English)

    王让会; 樊自立; 张慧芝; 陈亚萍; 马映军

    2002-01-01

    Based on remote sensing information sources including B/W aerial photos of 1983,pseudo-color aerial photos of 1992 and JERS-1/OPS VNIR image of 1996, vegetation types ofYingbazha, in the middle reaches of the Tarim River Basin in Xinjiang, China are mapped usingARC/INFO and related software. The changes in vegetation areas and distribution conditions areanalyzed. As a result of natural and human influences, vegetation changes have temporal andspatial characteristics. According to the principles of landscape ecology and geographical informa-tion science, the landscape changes are indicated. Moreover, the remote sensing and GIS tech-niques are integrated to study vegetation and its landscape.

  10. The distribution of submersed aquatic vegetation and water lettuce in the fresh and oligohaline tidal Potomac River, 2007

    Science.gov (United States)

    Campbell, Sarah Hunter; Rybicki, Nancy B.; Schenk, Edward R.

    2015-01-01

    Surveys documenting the composition of species of submersed aquatic vegetation (SAV) have been conducted in the Potomac River for decades. These surveys can help managers assess the proportion of native and exotic plants in the river or can be used to determine relationships between native and exotic plants, environmental conditions, and wildlife. SAV coverage increased from 2005 to 2007 throughout the fresh and oligohaline study area. The 2007 survey documented here determined that eleven species of SAV were present. The abundance of the exotic species Hydrilla verticillata (hydrilla) was relatively low, and species diversity was relatively high compared to previous years. The survey also revealed a new population of the invasive, floating aquatic plant Pistia stratiotes (water lettuce). In 2007, water lettuce, the latest exotic aquatic plant to be found in the fresh to oligohaline portion of the Potomac River, was most abundant in Mattawoman Creek, Charles County, Maryland. However, it was not observed in the fresh to oligohaline portion of the Potomac River in the summer of 2008. An understanding of the distribution of SAV species and factors governing the abundance of native and invasive aquatic species is enhanced by long-term surveys.

  11. Investigation of the impact of climate change on river water temperature: possible mitigation measures using riparian vegetation

    Science.gov (United States)

    Weihs, Philipp; Trimmel, Heidelinde; Formayer, Herbert; Kalny, Gerda; Rauch, Hans Peter; Leidinger, David

    2016-04-01

    Water stream temperature is a relevant factor for water quality since it is an important driver of water oxygen content and in turn also reduces or increases stress on the aquatic fauna. The water temperature of streams is determined by the source and inflow water temperature, by the energy balance at the stream surface and by the hydrological regime of the stream. Main factors driving the energy balance of streams are radiation balance and air temperature which influence the sensitive and latent heat flux. The present study investigates the influence of climate change on water temperature of streams and the potential of riparian vegetation to mitigate its effects. Within the scope of the project BIO_CLIC routine measurements of water temperature at 33 locations alongside the rivers Pinka and Lafnitz were performed from spring 2012 until autumn 2014. In addition meteorological measurements of global shortwave and longwave radiation, air temperature, wind and air humidity were carried out during this time. For the same time period, data of discharge and water levels of both rivers were provided by the public hydrological office. This time period also includes the heat episode of summer 2013 during which the highest air temperature ever recorded in Austria was reported on 8 August at 40.5°C. In the lower reaches of the river Pinka, at the station Burg the monthly mean water temperature of August 2013 was with more than 22°C, 1°C higher than the mean water temperature of the same period of the previous years. At the same station, the maximum water temperature of 27.1°C was recorded on 29 July, 9 days prior to the air temperature record. Analysis shows that at the downstream stations the main driving parameter is solar radiation whereas at the upstream stations a better correlation between air temperature and water temperature is obtained. The influence of riparian vegetation on water temperature, leading to lower water temperature by shading, is also detectable

  12. Bioengineering in front of a river dike: Wave attenuation by vegetation

    NARCIS (Netherlands)

    Oude, de R.; Augustijn, D.C.M.; Wijnberg, K.M.; Dekker, F.; Vries, de M.B.; Suzuki, T.; Christodoulou, George C.; Stamou, Anastasios

    2010-01-01

    Bioengineering is a novel way to reduce the application or dimensions of hard constructions. In the Dutch Noordwaard polder a vegetation field is proposed in front of a planned dike to damp waves such that the desired dike height can be reduced. To investigate the impact of vegetation on waves, the

  13. Vegetable production after flooded rice improves soil properties in the Red River Delta, Vietnam

    NARCIS (Netherlands)

    Everaarts, A.P.; Neeteson, J.J.; Pham Thi Thu, H.; Struik, P.C.

    2015-01-01

    Vegetable production in South East Asia often is in rotation with °ooded rice. The puddling of the soil with flooded rice production may result in unfavourable soil conditions for the subsequent production of dry land crops. To establish whether permanent vegetable production results in favourable s

  14. Response of Riparian Vegetation in AUSTRALIA"S Largest River Basin to Inter and Intra-Annual Climate Variability and Flooding as Quantified with Landsat and Modis

    Science.gov (United States)

    Broich, M.; Tulbure, M. G.

    2016-06-01

    Australia is a continent subject to high rainfall variability, which has major influences on runoff and vegetation dynamics. However, the resulting spatial-temporal pattern of flooding and its influence on riparian vegetation has not been quantified in a spatially explicit way. Here we focused on the floodplains of the entire Murray-Darling Basin (MDB), an area that covers over 1M km2, as a case study. The MDB is the country's primary agricultural area with scarce water resources subject to competing demands and impacted by climate change and more recently by the Millennium Drought (1999-2009). Riparian vegetation in the MDB floodplain suffered extensive decline providing a dramatic degradation of riparian vegetation. We quantified the spatial-temporal impact of rainfall, temperature and flooding patters on vegetation dynamics at the subcontinental to local scales and across inter to intra-annual time scales based on three decades of Landsat (25k images), Bureau of Meteorology data and one decade of MODIS data. Vegetation response varied in space and time and with vegetation types, densities and location relative to areas frequently flooded. Vegetation degradation trends were observed over riparian forests and woodlands in areas where flooding regimes have changed to less frequent and smaller inundation extents. Conversely, herbaceous vegetation phenology followed primarily a `boom' and `bust' cycle, related to inter-annual rainfall variability. Spatial patters of vegetation degradation changed along the N-S rainfall gradient but flooding regimes and vegetation degradation patterns also varied at finer scale, highlighting the importance of a spatially explicit, internally consistent analysis and setting the stage for investigating further cross-scale relationships. Results are of interest for land and water management decisions. The approach developed here can be applied to other areas globally such as the Nile river basin and Okavango River delta in Africa or the

  15. Response of Riparian Vegetation in Australia's Largest River Basin to Inter and Intra-Annual Climate Variability and Flooding as Quantified with Landsat and MODIS

    Science.gov (United States)

    Broich, M.; Tulbure, M. G.

    2015-12-01

    Australia is a continent subject to high rainfall variability, which has major influences on runoff and vegetation dynamics. However, the resulting spatial-temporal pattern of flooding and its influence on riparian vegetation has not been quantified in a spatially explicit way. Here we focused on the floodplains of the entire Murray-Darling Basin (MDB), an area that covers over 1M km^2, as a case study. The MDB is the country's primary agricultural area with scarce water resources subject to competing demands and impacted by climate change and more recently by the Millennium Drought (1999-2009). Riparian vegetation in the MDB floodplain suffered extensive decline providing a dramatic degradation of riparian vegetation. We quantified the spatial-temporal impact of rainfall, temperature and flooding patters on vegetation dynamics at the sub- continental to local scales and across inter to intra-annual time scales based on three decades of Landsat (25k images), Bureau of Meteorology data and one decade of MODIS data. Vegetation response varied in space and time and with vegetation types, densities and location relative to areas frequently flooded. Vegetation degradation trends were observed over riparian forests and woodlands in areas where flooding regimes have changed to less frequent and smaller inundation extents. Conversely, herbaceous vegetation phenology followed primarily a 'boom' and 'bust' cycle, related to inter-annual rainfall variability. Spatial patters of vegetation degradation changed along the N-S rainfall gradient but flooding regimes and vegetation degradation patterns also varied at finer scale, highlighting the importance of a spatially explicit, internally consistent analysis and setting the stage for investigating further cross-scale relationships. Results are of interest for land and water management decisions. The approach developed here can be applied to other areas globally such as the Nile river basin and Okavango River delta in Africa or

  16. Using remote sensing time series to model the impact of changing flooding regimes on riparian vegetation in Australia's most important river basin

    Science.gov (United States)

    Broich, M.; Tulbure, M. G.; Verbesselt, J.; Xin, Q.

    2016-12-01

    Australia is a continent subject to high rainfall variability, which has major influences on runoff and vegetation dynamics. However, the resulting spatial-temporal pattern of flooding and its influence on riparian vegetation has not been quantified in a spatially explicit way. Here we focused on the floodplains of the entire Murray-Darling Basin (MDB), an area that covers over 1M km2, as a case study. The MDB is the country's primary agricultural area with scarce water resources subject to competing demands and impacted by climate change and more recently by the Millennium Drought (1999-2009). Riparian vegetation in the MDB floodplain suffered extensive decline providing a dramatic degradation of riparian vegetation. We quantified the spatial-temporal impact of rainfall, temperature and flooding patters on vegetation dynamics at the subcontinental to local scales and across inter to intra-annual time scales based on three decades of Landsat (25k images), Bureau of Meteorology data and one decade of MODIS data. Vegetation response varied in space and time and with vegetation types, densities and location relative to areas frequently flooded. Vegetation degradation trends were observed over riparian forests and woodlands in areas where flooding regimes have changed to less frequent and smaller inundation extents. Conversely, herbaceous vegetation phenology followed primarily a `boom' and `bust' cycle, related to inter-annual rainfall variability. Spatial patters of vegetation degradation changed along the N-S rainfall gradient but flooding regimes and vegetation degradation patterns also varied at finer scale, highlighting the importance of a spatially explicit, internally consistent analysis and setting the stage for investigating further cross-scale relationships. Results are of interest for land and water management decisions. The approach developed here can be applied to other areas globally such as the Nile river basin and Okavango River delta in Africa or the

  17. On the importance of including vegetation dynamics in hydrological simulation under climate change: A case study in the Jing River Basin

    Science.gov (United States)

    Li, Q.; Li, Z.; Ishidaira, H.

    2012-04-01

    The role of catchment vegetation within the hydrological cycle and its impact on hydrological processes has long been a topic of research within hydrology. A key element in quantifying the hydrological impact of climate change is the relationship between catchment vegetation and runoff, which continues to be a productive area of research within hydrology. However, the parameterization of vegetation composition and distribution as a dynamic component is insufficient in stand-alone hydrological modeling studies. Dynamic global vegetation models (DGVMs) are able to simulate transient structural changes in major vegetation types but do not simulate runoff generation reliably. A biosphere hydrological model (LPJH) coupling a prominent DGVM (Lund-Postdam-Jena model referred to as LPJ) with a stand-alone hydrological model (HYMOD) may simulate both vegetation dynamics and runoff generation reasonably. This study applies the LPJH model to the Jing River basin, a tributary of the Yellow River, with the objective of analyzing the role of vegetation in the hydrological processes at this semi-arid basin and evaluating the impact of vegetation change on the hydrological processes under climate change. The results show that the LPJH model gives reasonable hydrological simulation in terms of runoff. It is shown that changing climate conditions in terms of co2, temperature, precipitation, and the combination changes of these variables would result in actual evapotranspiration and runoff changes. Theses changes are mainly attributable to changes in transpiration driven by vegetation dynamics, which are not simulated in stand-alone hydrological models. Therefore, the composition and distribution of vegetation are of fundamental importance for evapotranspiration and runoff generation, especially under climate change. The percent of impact from each climate variable is also explored by using the LPJH model, which gives an overall view of climate change impact on hydrological processes

  18. Influence of agricultural practice on trace metals in soils and vegetation in the water conservation area along the East River (Dongjiang River), South China

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Chunling, E-mail: clluo@gig.ac.cn [Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Yang, Renxiu [Department of Civil and Structural Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Wang, Yan; Li, Jun; Zhang, Gan [Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Li, Xiangdong [Department of Civil and Structural Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)

    2012-08-01

    Dongjiang (East River) is the key resource of potable water for the Pearl River Delta region, South China. Although industrial activities are limited in the water conservation area along this river, agriculture is very intensive. The present study evaluated trace metals in four soils under different cultivation. The total concentrations of trace metals decreased in the order orchard soil > vegetable soil > paddy soil > natural soil, reflecting decreasing inputs of agrochemicals to soils. Relatively high concentrations of Cd were recorded in the 60-cm soil profiles. The {sup 206}Pb/{sup 207}Pb ratio in the above-ground tissues of plant was significantly lower than their corresponding soils. In combination with the low transfer factor of Pb from soil to plant shoots, atmospheric deposition is probably a major pathway for Pb to enter plant leaves. Regular monitoring on the soil quality in this area is recommended for the safety of water resource and agricultural products. - Highlights: Black-Right-Pointing-Pointer Soil Cd exceeded the upper limit of Chinese standard for agricultural soils. Black-Right-Pointing-Pointer Relatively high concentrations of Cd were recorded in the 60-cm soil profiles. Black-Right-Pointing-Pointer Agricultural soil had higher concentrations of metals and lower {sup 206}Pb/{sup 207}Pb ratios. Black-Right-Pointing-Pointer Pb in above-ground tissues of plant was more anthropogenic than soil. Black-Right-Pointing-Pointer Atmospheric deposition may be a major pathway for Pb to enter plant leaves.

  19. Influence of urbanization on the original vegetation cover in urban river basin: case study in Campinas/SP, Brazil

    Science.gov (United States)

    Leite Silva, Alessandra; Márcia Longo, Regina

    2017-04-01

    ABSTRACT: In most Brazilian municipalities, urban development was not based on adequate planning; one of the consequences was the reduction of the original vegetation, limiting the forest formations to scarce and isolated fragments. In Campinas, São Paulo, Brazil, the vegetation fragmentation was mainly related to the expeditions and to the cycles of sugar cane and coffee. In this way, the present study aims to identify, quantify and evaluate the remaining arboreal vegetation spatial distribution in the Anhumas River Basin - Campinas/SP, Brazil. This study was developed with the aid of GIS software and field visits in order to construct a diagnosis of these areas and subsidize future actions required and to discuss the influence of urbanization on the original vegetation cover. The area was initially occupied by the Atlantic Forest (semi-deciduous forest) and drains one of the oldest urban occupation areas in the municipality; according to researchers, based on the water and geomorphological conditions of the basin, it can be subdivided into high, medium and low course. With a total area of 156,514 km2, only 16.74% are classified as green areas; where just 1.07% and 6.17% of total area represents forests and reforestation areas, respectively. The remaining green areas consists of: wetlands close to water bodies, but with no presence of trees and shrubs (area of 0.12% of the basin); urban green space, including parks and squares (2.19%); and natural field, constituted by natural non-arboreous vegetation (7.18%). In a scenario like this, a characteristic situation is the forest fragmentation; this process results in native vegetation remnants, isolated and more susceptible to external interference, coming from, for example, the proximity to agricultural areas or others land uses. The ecological knowledge of the remnants and their correct management can not only make it possible to diagnose current problems and to estimate future influences, but also to point out the

  20. Soil erosion and sediment yield and their relationships with vegetation cover in upper stream of the Yellow River.

    Science.gov (United States)

    Ouyang, Wei; Hao, Fanghua; Skidmore, Andrew K; Toxopeus, A G

    2010-12-15

    Soil erosion is a significant concern when considering regional environmental protection, especially in the Yellow River Basin in China. This study evaluated the temporal-spatial interaction of land cover status with soil erosion characteristics in the Longliu Catchment of China, using the Soil and Water Assessment Tool (SWAT) model. SWAT is a physical hydrological model which uses the RUSLE equation as a sediment algorithm. Considering the spatial and temporal scale of the relationship between soil erosion and sediment yield, simulations were undertaken at monthly and annual temporal scales and basin and sub-basin spatial scales. The corresponding temporal and spatial Normalized Difference Vegetation Index (NDVI) information was summarized from MODIS data, which can integrate regional land cover and climatic features. The SWAT simulation revealed that the annual soil erosion and sediment yield showed similar spatial distribution patterns, but the monthly variation fluctuated significantly. The monthly basin soil erosion varied from almost no erosion load to 3.92 t/ha and the maximum monthly sediment yield was 47,540 tones. The inter-annual simulation focused on the spatial difference and relationship with the corresponding vegetation NDVI value for every sub-basin. It is concluded that, for this continental monsoon climate basin, the higher NDVI vegetation zones prevented sediment transport, but at the same time they also contributed considerable soil erosion. The monthly basin soil erosion and sediment yield both correlated with NDVI, and the determination coefficients of their exponential correlation model were 0.446 and 0.426, respectively. The relationships between soil erosion and sediment yield with vegetation NDVI indicated that the vegetation status has a significant impact on sediment formation and transport. The findings can be used to develop soil erosion conservation programs for the study area.

  1. Numerical Simulation of the Impact of Vegetation Index on the Interannual Variation of Summer Precipitation in the Yellow River Basin

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Two sets of numerical experiments using the coupled National Center for Environmental Prediction General Circulation Model (NCEP/GCM T42L18) and the Simplified Simple Biosphere land surface scheme (SSiB) were carried out to investigate the climate impacts of fractional vegetation cover (FVC)and leaf area index (LAI) on East Asia summer precipitation, especially in the Yellow River Basin (YRB).One set employed prescribed FVC and LAI which have no interannual variations based on the climatology of vegetation distribution; the other with FVC and LAI derived from satellite observations of the International Satellite Land Surface Climate Project (ISLSCP) for 1987 and 1988. The simulations of the two experiments were compared to study the influence of FVC, LAI on summer precipitation interannual variation in the YRB. Compared with observations and the NCEP reanalysis data, the experiment that included both the effects of satellite-derived vegetation indexes and sea surface temperature (SST)produced better seasonal and interannual precipitation variations than the experiment with SST but no interannual variations in FVC and LAI, indicating that better representations of the vegetation index and its interannual variation may be important for climate prediction. The difference between 1987 and 1988indicated that with the increase of FVC and LAI, especially around the YRB, surface albedo decreased,net surface radiation increased, and consequently local evaporation and precipitation intensified. Further more, surface sensible heat flux, surface temperature and its diurnal variation decreased around the YRB in response to more vegetation. The decrease of surface-emitting longwave radiation due to the cooler surface outweighed the decrease of surface solar radiation income with more cloud coverage, thus maintaining the positive anomaly of net surface radiation. Further study indicated that moisture flux variations associated with changes in the general circulation also

  2. The impact of vegetation restoration on erosion-induced sediment yield in the middle Yellow River and management prospect

    Institute of Scientific and Technical Information of China (English)

    CHEN; Hao; ZHOU; Jinxing; CAI; Qiangguo; YUE; Zhongqi; LU

    2005-01-01

    According to the characteristics of water and erosion environments of different natural zones on the Loess Plateau, this paper studies changes of vegetation types, distribution boundaries of forest and grass as well as restoration capacity of vegetation in different natural zones in the middle Yellow River. The annual precipitation of 530 mm is the critical annual precipitation for forest and grass distribution in the middle Yellow River. Among the zonal and azonal environmental factors affecting watershed sediment yield, the intermediate diameter D50 (mm) of suspended load and forest coverage (V, %) play the leading role. Of them the effect weight of forest coverage (V, %) on catchments sediment yield is only 3.4% less than the role of the intermediate diameter (D50, mm), they are almost the same. To effectively control soil erosion in semiarid, especially in hilly-gullied areas and make sediment transport modulus reduce to less than 6000 t/km2, it is rather difficult by merely relying on natural restoration of forest. In the process of cultivated land conversion into forest land and grassland, measures suiting local conditions should be adopted in tree species selection and artificial afforestation (grass planting) based on management with biological measures for slopeland and engineering measures for hilly-gullied areas, so that watershed forest coverage in key counties can reach at least over 30%. Compared with the standard period of precipitation prior to the 1960s, with the decrease of annual precipitation at various periods, plant productivities decline to different degrees under natural conditions. The main reason accountable for the low survival rate of new seedlings and grass over years is due to precipitation decrease. In light with regression models of annual precipitation and natural vegetation productivities, it is possible to obtain estimated values of watershed natural vegetation productivity and eco-water consumption needed for the restoration to

  3. Goose Mass and Vegetation Data, Colville River Delta, Alaska, 2012-2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data release contains three tables of information from the Colville River Delta, Alaska, 2012-2014: offtake of Carex subspathacea, standing crop of C....

  4. Benthic Habitat Mapping - Indian River Lagoon, Florida Submerged Aquatic Vegetation (SAV) Data 1996 Geodatabase

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Office for Coastal Management's Coastal Change Analysis Program, in cooperation with the St. Johns River and South Florida Water Management Districts, used...

  5. Benthic Habitat Mapping - Indian River Lagoon, Florida Submerged Aquatic Vegetation (SAV) Data 1996 Geoform

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Office for Coastal Management's Coastal Change Analysis Program, in cooperation with the St. Johns River and South Florida Water Management Districts, used...

  6. Benthic Habitat Mapping - Indian River Lagoon, Florida Submerged Aquatic Vegetation (SAV) Data 1996 Substrate

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Office for Coastal Management's Coastal Change Analysis Program, in cooperation with the St. Johns River and South Florida Water Management Districts, used...

  7. Predicted riparian vegetation - Potential for Habitat Improvement in the Columbia River Basin

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Basin-wide analysis of potential to improve tributary habitats in the Columbia River basin through restoration of habitat-forming processes. Identification of...

  8. Yellow River vegetation and wildlife surveys: Report for Necedah National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The lower stretches of the Yellow River support some of Wisconsin's most diverse communities. The unique character of this community is evidenced by the number of...

  9. Color Infrared Orthorectified Photomosaic Leaf-off for Bluestone National Scenic River Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — Orthorectified color infrared ERDAS Imagine and MRSid image of Bluestone National Scenic River (final_blue.img). Produced from 43 color infrared photos taken March...

  10. Benthic Habitat Mapping - Indian River Lagoon, Florida Submerged Aquatic Vegetation (SAV) Data 1996 Biotic

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Office for Coastal Management's Coastal Change Analysis Program, in cooperation with the St. Johns River and South Florida Water Management Districts, used...

  11. Follow-up observations of vegetation associated with the Atigun River floodplain oil spill

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report is a summary of the results of botanical investigations conducted along the Atigun River, associated side channels and tributaries during the period 6, 7...

  12. Riparian vegetation abundance (percent cover) in the Elwha River estuary, Washington, in 2007 and 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This portion of the data release presents riparian plant species abundance (percent cover) data from plots sampled in the Elwha River estuary, Washington, in 2007...

  13. Riparian vegetation species richness in the Elwha River estuary, Washington, in 2007 and 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This portion of the data release presents riparian plant species richness (number of unique taxa) data from plots sampled in the Elwha River estuary, Washington, in...

  14. Changes in groundwater levels and the response of natural vegetation to transfer of water to the lower reaches of the Tarim River

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Restoration and reconstruction of the degraded Tarim River ecosystem is an important challenge. A goal of an ecological water conveyance project is to protect and restore the natural vegetation in the lower reaches of Tarim River by transferring water from Bosten Lake, through the river channel, to the lower reaches. This study describes the changes in groundwater depth during the water transfer and the respondence of riparian vegetation to alterations in groundwater levels. The results indicate that groundwater depth along the Tarim River channel has a significant spatial-temporal component. Groundwater levels closest to the river channel show the most immediate and pronounced changes as a response to water transfer while those further away respond more slowly, although the observed change appears to be longer in duration. With a rise in the groundwater level, natural vegetation responded with higher growth rates, biomass and biodiversity. These favorable changes show that it is feasible to protect and restore the degraded natural vegetation by raising the groundwater depth. Plant communities are likely to reflect the hysteresis phenomenon, requiring higher water levels to initiate and stimulate desired growth than what may be needed to maintain the plant community. Because different species have different ecologies, including different root depths and densities and water needs, their response to increasing water availability will be spatially and temporally heterogenous. The response of vegetation is also influenced by microtopography and watering style. This paper discusses strategies for the protection and restoration of the degraded vegetation in the lower reaches of the Tarim River and provides information to complement ongoing theoretical research into ecological restoration in arid or semi-arid ecosystems.

  15. Climate change tendency and grassland vegetation response during the growth season in Three-River Source Region

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Climate change,climate suitablity change for grassland vegetation,and grassland response to climate change during the growth season are studied systematically by using meteorological data of temperature,precipitation,and length of sunlight from 1961 to 2007,NOAA/AVHRR NDVI from 1982 to 2006,and observations of grass height,biomass,and coverage in enclosed grassland from 1994 to 2006.Two models are developed to evaluate climate change and the climatic suitability of grassland vegetation growth.Average temperature,accumulative precipitation,and length of sunlight during the growth season increased from 1961 to 2007 at rates of 0.24°C/10 yr,2.32 mm/10 yr,and 2.81 h/10 yr,respectively.The increase rates of ave-rage temperature between April and May,and between June and August are 0.17 and 0.30°C/10 yr;accumulative rainfall between April and May increased at a rate of 2.80 mm/10 yr,and accumulative rainfall between June and August decreased at a rate of 0.38 mm/10 yr;the increase rates of accumulative length of sunlight between April and May,and between June and August are 2.15 and 1.2 h/10 yr.The climatic suitability of grassland vegetation growth showed an increasing trend,and the increase rate between April and May is greater than that between June and August.Both NDVI observations from 1982 to 2006 and measurements of grass height,dry biomass,and coverage from 1994 to 2006 show that the climate change has resulted in an increase in plant productivity of the grassland in Three-River Source Region.If some protection measures are taken as soon as possible,the deteriorated grassland in Three-River Source Region can recover.

  16. River flooding as a driver of polygon dynamics: modern vegetation data and a millennial peat record from the Anabar River lowlands (Arctic Siberia

    Directory of Open Access Journals (Sweden)

    R. Zibulski

    2013-03-01

    Full Text Available The spatial and temporal variability of a low-centred polygon on the eastern floodplain area of the lower Anabar River (72.070° N, 113.921° E, northern Yakutia, Siberia has been investigated using a multi-method approach. The present-day vegetation in each square metre was analysed revealing a community of Larix shrubby Betula and Salix on the polygon rim, a dominance of Carex and Andromeda polifolia in the rim-to-pond transition zone, and a predominantly monospecific Scorpidium scorpioides coverage within the pond. The TOC content, TOC/TN ratio, grain-size, vascular plant macrofossils, moss remains, diatoms, and pollen were analysed for two vertical sections and a sediment core from a transect across the polygon. Radiocarbon dating indicates that the formation of the polygon started at least 1500 yr ago; the general positions of the pond and rim have not changed since that time. Two types of pond vegetation were identified, indicating two contrasting development stages of the polygon. The first was a well-established moss association dominated by submerged or floating Scorpidium scorpioides and/or Drepanocladus spp. and overgrown by epiphytic diatoms such as Tabellaria flocculosa and Eunotia taxa. This stage coincides temporally with a period in which the polygon was only drained by lateral subsurface water flow, as indicated by mixed grain sizes. A different moss association occurred during times of repeated river flooding (indicated by homogeneous medium-grained sand that probably accumulated during the annual spring snow melt, characterized by an abundance of Meesia triquetra and a dominance of benthic diatoms (e.g. Navicula vulpina, indicative of a relatively high pH and a high tolerance of disturbance. A comparison of the local polygon vegetation (inferred from moss and macrofossil spectra with the regional vegetation (inferred from pollen spectra indicated that the moss association with Scorpidium scorpioides became established during

  17. A Vegetation Database for the Colorado River Ecosystem from Glen Canyon Dam to the Western Boundary of Grand Canyon National Park, Arizona

    Science.gov (United States)

    Ralston, Barbara E.; Davis, Philip A.; Weber, Robert M.; Rundall, Jill M.

    2008-01-01

    A vegetation database of the riparian vegetation located within the Colorado River ecosystem (CRE), a subsection of the Colorado River between Glen Canyon Dam and the western boundary of Grand Canyon National Park, was constructed using four-band image mosaics acquired in May 2002. A digital line scanner was flown over the Colorado River corridor in Arizona by ISTAR Americas, using a Leica ADS-40 digital camera to acquire a digital surface model and four-band image mosaics (blue, green, red, and near-infrared) for vegetation mapping. The primary objective of this mapping project was to develop a digital inventory map of vegetation to enable patch- and landscape-scale change detection, and to establish randomized sampling points for ground surveys of terrestrial fauna (principally, but not exclusively, birds). The vegetation base map was constructed through a combination of ground surveys to identify vegetation classes, image processing, and automated supervised classification procedures. Analysis of the imagery and subsequent supervised classification involved multiple steps to evaluate band quality, band ratios, and vegetation texture and density. Identification of vegetation classes involved collection of cover data throughout the river corridor and subsequent analysis using two-way indicator species analysis (TWINSPAN). Vegetation was classified into six vegetation classes, following the National Vegetation Classification Standard, based on cover dominance. This analysis indicated that total area covered by all vegetation within the CRE was 3,346 ha. Considering the six vegetation classes, the sparse shrub (SS) class accounted for the greatest amount of vegetation (627 ha) followed by Pluchea (PLSE) and Tamarix (TARA) at 494 and 366 ha, respectively. The wetland (WTLD) and Prosopis-Acacia (PRGL) classes both had similar areal cover values (227 and 213 ha, respectively). Baccharis-Salix (BAXX) was the least represented at 94 ha. Accuracy assessment of the

  18. BIOINDICATION USING VEGETATION OF THREE REGULATED RIVERS UNDER AGRO-INDUSTRIAL PRESSURE IN WESTERN FRANCE

    Directory of Open Access Journals (Sweden)

    D. LE COEUR

    2004-01-01

    Full Text Available The longitudinal changes of richness and composition of aquatic plants have been studied from headwaters to the fifth stream order in three near-by rivers or Western Brittany (France, the Orne, Sélune and Rance. All rivers were regulated years ago with dams located on the lower third of the studies river stretches. A shifting evolution of the macrophyte richness was revealed in a previous study along the river continuum, related 10 habitat heterogeneity. influences of regulated sectors and geological changes. Nutrient enrichment and organic pollution influences were the main secondary gradients. On this basis we improved a methodology to complete a biotic index used in Europe for water trophy assessment, following the European water frame work directive the IBMR based on aquatic plant survey: a validation with classical statistical tests and a comparison to a canonical analysis were performed. Finally this approach permitted to make a proposition of adaptation of the index to the Local particularities of each three high anthropised rivers

  19. BIOINDICATION USING VEGETATION OF THREE REGULATED RIVERS UNDER AGRO-INDUSTRIAL PRESSURE IN WESTERN FRANCE

    Directory of Open Access Journals (Sweden)

    I. BERNEZ

    2004-05-01

    Full Text Available The longitudinal changes of richness and composition of aquatic plants have been studied from headwaters to the fifth stream order in three near-by rivers or Western Brittany (France, the Orne, Sélune and Rance. All rivers were regulated years ago with dams located on the lower third of the studies river stretches. A shifting evolution of the macrophyte richness was revealed in a previous study along the river continuum, related 10 habitat heterogeneity. influences of regulated sectors and geological changes. Nutrient enrichment and organic pollution influences were the main secondary gradients. On this basis we improved a methodology to complete a biotic index used in Europe for water trophy assessment, following the European water frame work directive the IBMR based on aquatic plant survey: a validation with classical statistical tests and a comparison to a canonical analysis were performed. Finally this approach permitted to make a proposition of adaptation of the index to the Local particularities of each three high anthropised rivers

  20. Assessment of the contamination of riparian soil and vegetation by trace metals--A Danube River case study.

    Science.gov (United States)

    Pavlović, P; Mitrović, M; Đorđević, D; Sakan, S; Slobodnik, J; Liška, I; Csanyi, B; Jarić, S; Kostić, O; Pavlović, D; Marinković, N; Tubić, B; Paunović, M

    2016-01-01

    The aim of this study was to assess the spatial distribution of arsenic and heavy metals (Cd, Cr, Cu Hg, Ni, Pb and Zn) in a riparian area influenced by periodical flooding along a considerable stretch of the Danube River. This screening was undertaken on soil and plant samples collected from 43 sites along 2386 km of the river, collected during the international Joint Danube Survey 3 expedition (ICPDR, 2015). In addition, data on the concentration of these elements in river sediment was used in order to describe the relationship between sediment, riparian soil and riparian plants. A significant positive correlation (Spearman r, for psoil (r=0.817). A significant correlation between soil and plants (r=0.438) and sediment and plants (r=0.412) was also found for trace metal concentrations. Elevated levels of Cd, Cr, Cu, and Ni were found at certain sites along the Serbian stretch, while elevated concentrations of Hg were also detected in Hungary, of Pb along the Romanian stretch and of As along the Bulgarian stretch (the Lower Danube). These results point to the presence of naturally-occurring metals derived from ore deposits in the Danube River Basin and anthropogenic metals, released by mining and processing of metal ores and other industrial facilities, which are responsible for the entry of metals such as Cu, Ni and Zn. Our results also indicated toxic Cd and Zn levels in plant samples, measured at the Hercegsznato site (Middle Danube, Hungary), which highlighted these elements as a potential limiting factor for riparian vegetation in that area. The distribution of the analysed elements in plant material also indicates the species-specific accumulation of trace metals. Based on our results, the Lower and Middle Danube were found to be more polluted in terms of the analysed elements.

  1. Riparian vegetation dynamics and evapotranspiration in the riparian corridor in the delta of the Colorado River, Mexico.

    Science.gov (United States)

    Nagler, Pamela L; Glenn, Edward P; Hinojosa-Huerta, Osvel; Zamora, Francisco; Howard, Keith

    2008-09-01

    Like other great desert rivers, the Colorado River in the United States and Mexico is highly regulated to provide water for human use. No water is officially allotted to support the natural ecosystems in the delta of the river in Mexico. However, precipitation is inherently variable in this watershed, and from 1981-2004, 15% of the mean annual flow of the Lower Colorado River has entered the riparian corridor below the last diversion point for water in Mexico. These flows include flood releases from US dams and much smaller administrative spills released back to the river from irrigators in the US and Mexico. These flows have germinated new cohorts of native cottonwood and willow trees and have established an active aquatic ecosystem in the riparian corridor in Mexico. We used ground and remote-sensing methods to determine the composition and fractional cover of the vegetation in the riparian corridor, its annual water consumption, and the sources of water that support the ecosystem. The study covered the period 2000-2004, a flood year followed by 4 dry years. The riparian corridor occupies 30,000 ha between flood control levees in Mexico. Annual evapotranspiration (ET), estimated by Moderate Resolution Imaging Spectrometer (MODIS) satellite imagery calibrated against moisture flux tower data, was about 1.1 m yr(-1) and was fairly constant throughout the study period despite a paucity of surface flows 2001-2004. Total ET averaged 3.4 x 10(8)m(3)yr(-1), about 15% of Colorado River water entering Mexico from the US Surface flows could have played only a small part in supporting these high ET losses. We conclude that the riparian ET is supported mainly by the shallow regional aquifer, derived from agricultural return flows, that approaches the surface in the riparian zone. Nevertheless, surface flows are important in germinating cohorts of native trees, in washing salts from the soil and aquifer, and in providing aquatic habitat, thereby enriching the habitat value of

  2. 76 FR 31933 - Tonto National Forest; AZ; Salt River Allotments Vegetative Management EIS

    Science.gov (United States)

    2011-06-02

    ... subordinate role of a single resource use or activity within analysis area ecosystems. Since one tool under... fire would be managed to protect, maintain, and enhance Federal lands in a cost effective manner. A... property and natural/cultural resources. Sonoran Desert and riparian vegetation types would be...

  3. Biogeochemical constraints on the ecological rehabilitation of wetland vegetation in river floodplains

    NARCIS (Netherlands)

    Lamers, L.P.M.; Loeb, R.; Antheunisse, A.M.; Miletto, M.; Lucassen, E.C.H.E.T.; Boxman, A.W.; Smolders, A.J.P.; Roelofs, J.

    2006-01-01

    The European policy for river management during peak discharge periods is currently changing from exclusion strategies (reinforcement of dykes) to allowing a more natural situation by creating more floodplain space to reduce water levels during peak discharges. In addition, water retention and water

  4. Shore Vegetation of Lakes Oahe and Sakakawea, Mainstream Missouri River Reservoirs.

    Science.gov (United States)

    1978-04-01

    Solanum rostratum and Grindelia squarrosa; both were more abundant on ungrazed plots at Grand River (Table 15). Important species on ungrazed plots at...abundant on grazed plots. Small amounts of Grindelia squarrosa, Medicago lupulina and Polygonum achoreum were present on grazed plots only at Garrison

  5. Wind tunnel experiments of air flow patterns over nabkhas modeled after those from the Hotan River basin,Xinjiang,China(Ⅱ):vegetated

    Institute of Scientific and Technical Information of China (English)

    Zhizhong LI; Rong MA; ShengLi WU; Janis DALE; Lin GE; Mudan HE; Xiaofeng WANG; Jianhui JIN; Jinwei LIU; Wanjuan LI

    2008-01-01

    This paper examines the results of wind tunnel experiments on models of nabkha,based on those studied in the Hotan River basin.Semi-spherical and conical models of nabkhas were constructed at a ratio of 40:1 in light of the on-site observation.Artificial vegetation of simulated Tamarix spp.was put on top of each model.Parameters of the shape,including height,width,and diameter of vegetated semi-spherical and conical nabkha.were measured in the Hotan River basin.Wind tunnel experiments on the semi-spherical and conical nabkha used clean air devoid of additional sediments at five different wind speeds (6-14 m/s)to study the influence of vegetation on airflow patterns.Results of the experiments indicate that vegetation at the top of the nabkhas enhances the surface roughness of the sand mounds,retards airflow over the sand mounds,reduces airflow energy,eliminates erosional pits occurring on the top surface of non-vegetated sand mounds and enhances the range of influence of the vortex that forms on the leeward slope.Vegetation changes the airflow pattern upwind and downwind of the sand mound and reduces the transport of sand away from the nabkha.This entrapment of sediment by the vegetation plays an important role in sustaining the nabkha landscape of the study area.The existence of vegetation makes fine materials in wind-sand flow to possibly deposit,and promotes nabkha formation.The imitative flow patterns Of different morphological nabkhas have also been verified by on-site observation in the river basin.

  6. Experimental investigation of the effect of vegetation on soil, sediment erosion, and salt transport processes in the Upper Colorado River Basin Mancos Shale formation, Price, Utah, USA.

    Science.gov (United States)

    Because of concerns about salinity in the Colorado River, this study focused on saline and sodic soils associated with the Mancos Shale formation with the objective of investigating mechanisms driving sediment yield and salinity loads and the role of vegetation in altering soil chemistry in the Pric...

  7. The interrelationship of riparian vegetation and water temperature demonstrated with field data measurements and analysis of the rivers Pinka and Lafnitz

    Science.gov (United States)

    Holzapfel, Gerda; Rauch, Hans Peter; Weihs, Philipp; Trimmel, Heidelinde

    2015-04-01

    Riparian vegetation is an important part of riverine system and plays a key role in terms of eco-sustainable streams, which consequently also affect the water driven erosion processes and flooding from an engineering point of view. Furthermore it is a crucial prerequisite for intact and balanced terrestrial and aquatic ecosystems. Due to intensive anthropogenic impacts, especially in lowlands, streams in Central Europe were strongly influenced and set to a moderate ecological status. Riverine forests changed to settlements or agricultural areas and so important functions of the riparian vegetation, such as shading decreased. Consequently, stream warming occurs and has an impact on the water quality of small and moderate sized streams. The objective of this study is to correlate different vegetation parameters and the river water temperature. The study was carried out in the Pinka and Lafnitz river catchments, located in the Austrian provinces Styria and Burgenland. Both rivers are medium sized lowland rivers of the "Hungarian Plains". Digital aerial photograph analysis and field measurements are the basement of the vegetation analysis. Water temperature was measured at several points along both rivers. Data were sampled every hour from July 2012 until September 2013. For the water temperature measurements HOBO Pendant Temperature/Light Data Logger 8K * UA-002-08 were used. The results show that there is a correlation between water temperature and riparian vegetation parameter depending on the temporal and spatial scale. There is a verifiable difference in daily water temperature range (6.7° to 3.5°) of different vegetation stands in contrast to unshaded areas. Also the peak time of the daily water temperature is different comparing high shaded areas with unshaded areas. The results confirm that the riparian vegetation has a significantly impact on the water temperature specifically at low water conditions and demonstrate the need for more in depth studies of this

  8. Remote Sensing of Submerged Aquatic Vegetation in a Shallow Non-Turbid River Using an Unmanned Aerial Vehicle

    Directory of Open Access Journals (Sweden)

    Kyle F. Flynn

    2014-12-01

    Full Text Available A passive method for remote sensing of the nuisance green algae Cladophora glomerata in rivers is presented using an unmanned aerial vehicle (UAV. Included are methods for UAV operation, lens distortion correction, image georeferencing, and spectral analysis to support algal cover mapping. Eighteen aerial photography missions were conducted over the summer of 2013 using an off-the-shelf UAV and three-band, wide-angle, red, green, and blue (RGB digital camera sensor. Images were post-processed, mosaicked, and georeferenced so automated classification and mapping could be completed. An adaptive cosine estimator (ACE and spectral angle mapper (SAM algorithm were used to complete the algal identification. Digital analysis of optical imagery correctly identified filamentous algae and background coverage 90% and 92% of the time, and tau coefficients were 0.82 and 0.84 for ACE and SAM, respectively. Thereafter, algal cover was characterized for a one-kilometer channel segment during each of the 18 UAV flights. Percent cover ranged from <5% to >50%, and increased immediately after vernal freshet, peaked in midsummer, and declined in the fall. Results indicate that optical remote sensing with UAV holds promise for completing spatially precise, and multi-temporal measurements of algae or submerged aquatic vegetation in shallow rivers with low turbidity and good optical transmission.

  9. Enhancing Floodplain Management in the Lower Mekong River Basin Using Vegetation and Water Cycle Satellite Observations

    Science.gov (United States)

    Bolten, J. D.; Spruce, J.; Wilson, R.; Strauch, K.; Doyle, T.; Srinivan, R.; Lakshmi, V.; Gupta, M.

    2014-12-01

    The Lower Mekong River Basin shared by China, Burma, Laos, Thailand, Cambodia, and Vietnam, is considered the lifeblood of Southeast Asia. The Mekong Basin is subject to large hydrological fluctuations on a seasonal and inter-annual basis. The basin remains prone to severe annual floods that continue to cause widespread damage and endanger food security and the livelihood of the millions who dwell in the region. Also the placement of newly planned dams primarily for hydropower in the Lower Mekong Basin may cause damaging social, agriculture and fisheries impacts to the region where we may now likely be at a critical 'tipping point'. The primary goal of this project is to apply NASA and USGS products, tools, and information for improved flood and water management in the Lower Mekong River Basin to help characterize, understand, and predict future changes on the basin. Specifically, we are providing and helping transfer to the Mekong River Commission (MRC) and the member countries of Thailand, Cambodia, Lao, Vietnam, and Burma the enhanced Soil and Water Assessment Tool (SWAT) using remotely sensed surface, ground water, and root zone soil moisture along with improved Land Use and Land Cover (LULC) maps. In order to estimate the flood potential and constrain the SWAT Available Water Capacity model parameter over the region, we are assimilated GRACE Terrestrial Water Storage observations into the Catchment Land Surface Model. In addition, a Graphic Visualization Tool (GVT) as been developed to work in concert with the output of the SWAT model parameterized for the Mekong Basin as an adjunct tool of the MRC Decision Support Framework. The project requires a close coordination of the development and assessment of the enhanced MRC SWAT with the guidance of MRC resource managers and technical advisors. This presentation will evaluate the skill of the enhanced SWAT model using qualitative (i.e., MODIS change detection) and quantitative (e.g., streamflow) metrics over one

  10. The role of catchment vegetation in reducing atmospheric inputs of pollutant aerosols in Ganga river.

    Science.gov (United States)

    Shubhashish, Kumar; Pandey, Richa; Pandey, Jitendra

    2012-08-01

    The role of woody perennials in the Ganga river basin in modifying the run-off quality as influenced by atmospheric deposition of pollutant aerosols was investigated. The concentration of seven nutrients and eight metals were measured in atmospheric deposits as well as in run-off water under the influence of five woody perennials. Nutrient retention was recorded maximum for Bougainvillea spectabilis ranged from 4.30 % to 33.70 %. Metal retention was recorded highest for Ficus benghalensis ranged from 5.15 % to 36.98 %. Although some species showed nutrient enrichment, all the species considered in the study invariably contribute to reduce nutrients and metal concentration in run-off water. Reduction in run off was recorded maximum for B. spectabilis (nutrient 6.48 %-40.66 %; metal 7.86 %-22.85 %) and minimum for Ficus religiosa (nutrient 1.68 %-27.19 %; metal 6.55 %-31.55 %). The study forms the first report on the use of woody perennials in reducing input of atmospheric pollutants to Ganga river and has relevance in formulating strategies for river basin management.

  11. Influence of riparian vegetation on near-bank flow structure and erosion rates on a large meandering river

    Science.gov (United States)

    Konsoer, K. M.; Rhoads, B. L.; Langendoen, E. J.; Johnson, K.; Ursic, M.

    2012-12-01

    Rates of meander migration are dependent upon dynamic interactions between planform geometry, three-dimensional flow structure, sediment transport, and the erodibility and geotechnical properties of the channel banks and floodplains. Riparian vegetation can greatly reduce the rate of migration through root-reinforcement and increased flow resistance near the bank. In particular, forested riverbanks can also provide large woody debris (LWD) to the channel, and if located near the outer bank, can act to amour the bank by disrupting three-dimensional flow patterns and redirecting flow away from the bank-toe, the locus of erosion in meandering rivers. In this paper, three-dimensional flow patterns and migration rates are compared for two meander bends, one forested and one non-forested, on the Wabash River, near Grayville, Illinois. Flow data were obtained using acoustic Doppler current profilers (ADCP) for two large flow events in May and June 2011. LWD was mapped using a terrestrial LiDAR survey, and residence times for the LWD were estimated by comparing the survey data to time-series aerial photography. Rates of migration and planform evolution were determined through time-series analysis of aerial photography from 1938-2011. Results from this study show that near-bank LWD can have a significant influence on flow patterns through a meander bend and can disrupt helical flow near the outer bank, thereby reducing the effect of the high velocity core on the toe of the bank. Additionally, these effects influence migration rates and the planform evolution of meandering rivers.

  12. Impacts of mute swans (Cygnus olor) on submerged aquatic vegetation in Illinois River Valley backwaters

    Science.gov (United States)

    Stafford, Joshua D.; Michael W. Eichholz,; Adam C. Phillips,

    2012-01-01

    Wetland loss in North America has been considerable and well documented, and the establishment of exotic species in remaining wetlands can further reduce their ability to support native flora and fauna. In the Chesapeake Bay and Great Lakes ecosystems, exotic mute swans (Cygnus olor) have been found to negatively impact wetlands through degradation of submerged aquatic vegetation (SAV) communities. Mute swan populations have expanded into many areas of mid-continental North America outside the Great Lakes ecosystem, but the environmental impact of these populations is not well known. Mid-continental wetlands in North America differ in physical characteristics (e.g., size, depth, and permanency) and aquatic vegetation species composition compared to wetlands in other areas where mute swans have been studied and, thus, may be more or less susceptible to degradation from swan herbivory. To investigate the impact of mute swan herbivory on SAV communities in mid-continent wetlands, we used exclosures to prevent swans from foraging in 2 wetland complexes in central Illinois. Above-ground biomass of vegetation did not differ between exclosures and controls; however, mean below-ground biomass was greater in exclosures (52.0 g/m2, SE = 6.0) than in controls (34.4 g/m2 SE = 4.0). Thus, although swan densities were lower in our study region compared to that of previous studies, we observed potentially detrimental impacts of swan herbivory on below-ground biomass of SAV. Our results indicate that both above-ground and below-ground impacts of herbivory should be monitored, and below-ground biomass may be most sensitive to swan foraging.

  13. Mineral weathering experiments to explore the effects of vegetation shifts in high mountain region (Wind River Range, Wyoming, USA)

    Science.gov (United States)

    Mavris, Christian; Furrer, Gerhard; Dahms, Dennis; Anderson, Suzanne P.; Blum, Alex; Goetze, Jens; Wells, Aaron; Egli, Markus

    2015-04-01

    Climate change influences the evolution of soil and landscape. With changing climate, both flora and fauna must adapt to new conditions. It is unknown in many respects to what extent soils will react to warming and vegetation change. The aim of this study was to identify possible consequences for soils in a dry-alpine region with respect to weathering of primary minerals and leaching of elements under expected warming climate conditions due to shifts in vegetation. To achieve this, a field empirical approach was used in combination with laboratory weathering experiments simulating several scenarios. Study sites located in Sinks Canyon and in Stough Basin of the Wind River Range, Wyoming, USA, encompass ecotones that consist of tundra, forest, or sagebrush (from moist to dry, with increasing temperature, respectively). All soils are developed on granitoid moraines. The mineralogy of the soils along the altitudinal sequence was analysed using cathodoluminescence and X-ray diffraction, and revealed clear mineral transformations: biotite and plagioclase were both weathered to smectite while plagioclase also weathered to kaolinite. Cooler, wetter, altitude-dependent conditions seemed to promote weathering of these primary minerals. To test the impact of soil solutions from different ecotones on mineral weathering, aqueous extracts from topsoils (A horizons) were reacted with subsoils (B horizons) in batch experiments. Aqueous extracts of topsoil samples were generated for all three ecotones, and these solutions were characterized. For the batch experiments, the topsoil extracts were reacted for 1800 hours with the subsoil samples of the same ecotone, or with the subsoil samples from higher altitude ecotones. Solutions collected periodically during the experiments were measured using ICP-OES and ion chromatography. Dissolved Ca, Mg and K were mainly controlled by the chemical weathering of oligoclase, K-feldspar and biotite. With increasing altitude (and consequently

  14. 拉萨河谷植被演替规律及人工恢复对策%Succession Patterns and Artificial Renewal Countermeasures of Lhasa River Valley Vegetation

    Institute of Scientific and Technical Information of China (English)

    丁云春

    2013-01-01

    The article described the distribution characteristics and succession patterns of Lhasa River Valley Vegetation, and analyzed the effects on human disturbances on the distribution of vegetation .It proposed the protection of existing natural vegetation , moderate usage of afforestation technology , ade-quate selection of afforestation plantation, the utilization of container seedling technique , development of alternative energy resources , proper usage of water resources and other vegetation renewal countermeasures .%阐述拉萨河谷植被分布特征及演替规律,分析人为干扰对植被分布的影响。提出保护残存的天然植被,适度的造林技术,适当选择造林树种,采用容器育苗技术,开发替代能源,合理利用水资源等植被恢复对策。

  15. Temporal changes of meadow and peatbog vegetation in the landscape of a small-scale river valley in Central Roztocze

    Directory of Open Access Journals (Sweden)

    Bożenna Czarnecka

    2015-07-01

    Full Text Available The Szum is a right-side tributary of the Tanew River crossing the southern escarpment zone of the Central Roztocze region (SE Poland. Downstream of the strict river break in a section between the 10th and 12th km of the river course in the Szum valley, meadow and peatbog complexes have developed, associated with semi-hydrogenic and marshy soils. In an area of approx. 13 ha of the most valuable non-forest habitats, a variety of plant communities have been identified, including habitats of the Natura 2000 network and habitats that are protected under the Regulation of the Minister of the Environment (2001. These are, for instance, meadow associations Lysimachio vulgaris-Filipenduletum, Lythro-Filipenduletum, Filipendulo ulmariae-Menthetum longifoliae, Angelico-Cirsietum oleracei, and Cirsietum rivularis. The moss–sedge and sphagnum bog communities comprise noteworthy associations Caricetum limosae, Rhynchosporetum albae, Caricetum lasiocarpae, Caricetum paniceo-lepidocarpae, Caricetum davallianae, and Sphagnetum magellanici. These communities are composed of ca. 160 vascular plant species and 40 moss and liverwort species. In 1999–2014, the greatest changes occurred within macroforb meadows, i.e. small Angelico-Cirsietum oleracei and Cirsietum rivularis patches have been transformed into Lysimachio vulgaris-Filipenduletum, while some patches of the latter association have been transformed into a Caricetum acutiformis rush. Several patches of bog-spring associations Caricetum paniceo-lepidocarpae and Carici canescentis-Agrostietum caninae have been irretrievably destroyed. Sphagnetum magellanici appears to be the least stable community among the preserved peatbogs. The changes of meadow and peatbog vegetation observed for the last 15 years are a consequence of natural processes that take place in the river valley and to a large extent human activity connected with the so-called small-scale water retention as well as the presence of a beaver

  16. Effects of vegetation on river flow: A review%植被对河道水流影响的研究进展

    Institute of Scientific and Technical Information of China (English)

    徐卫刚; 张化永; 王中玉; 黄文沛

    2013-01-01

    植被是自然河流的组成部分.明确植被与水流的相互影响,对于动植物栖息地的保护、水体富营养化的控制、河流和湖泊的生态修复,以及河道整治等方面均具有重要的科学和实践意义.本文回顾了国内外对河道植被与水流相互作用的研究状况,综述了植被对阻力系数、水流结构影响的研究,介绍了数值模拟在该领域的应用进展;基于文献资料,分析了河道断面形状、植株个体形态、植被分布格局等诸多因素对含植被水流流态的影响,阐述了在河流形态、时空尺度上植被变化、植被段内部水流分布、三维紊动模拟等方面深入研究河道植被水力学机制的重要性.%Vegetation is a component of the natural river. To understand the interaction between vegetation and water flow is of scientific and practical significance for the protection of wildlife habi-tats , the control of water body eutrophication, the ecological restoration of rivers and lakes, and the management of riverways. This paper reviewed the researches about the interaction between vegeta-tion and water flow in riverways, summarized the research progress in the effects of the vegetation on the resistance coefficient and water flow structure, and introduced the applications of numerical sim-ulation in this research field. Based on the previous studies, the effects of river section shape, plant individual form, and vegetation distribution pattern on the flow regime of water flow in vegetation section were analyzed. For further study, the importance of deeply understanding the hydraulics mechanisms of the interaction between vegetation and water flow in terms of the diversity of river morphology, the vegetation variation at different spatiotemporal scales, the water flow distribution in vegetation section, and the three dimensional turbulent simulation was expatiated.

  17. Metals and arsenic in soils and corresponding vegetation at Central Elbe river floodplains (Germany)

    Energy Technology Data Exchange (ETDEWEB)

    Overesch, M. [Department for Geo- and Agroecology, Institute of Spatial Analysis and Planning in Areas of Intensive Agriculture, University of Vechta, P.O. Box 1553, D-49364 Vechta (Germany)]. E-mail: moveresch@ispa.uni-vechta.de; Rinklebe, J. [Department of Soil Science, UFZ Center for Environmental Research Leipzig-Halle, Theodor-Lieser-Strasse 4, D-06120 Halle (Germany)]. E-mail: joerg.rinklebe@ufz.de; Broll, G. [Department for Geo- and Agroecology, Institute of Spatial Analysis and Planning in Areas of Intensive Agriculture, University of Vechta, P.O. Box 1553, D-49364 Vechta (Germany)]. E-mail: gbroll@ispa.uni-vechta.de; Neue, H.-U. [Department of Soil Science, UFZ Center for Environmental Research Leipzig-Halle, Theodor-Lieser-Strasse 4, D-06120 Halle (Germany)]. E-mail: heinz-ulrich.neue@ufz.de

    2007-02-15

    Floodplain soils at the Elbe river are frequently polluted with metals and arsenic. High contents of these pollutants were detected down to subsoil layers. NH{sub 4}NO{sub 3}-extractable (phytoavailable) Cd, Ni, and Zn were elevated in horizons with high acidity. Among five common floodplain plant species, Artemisia vulgaris showed highest concentrations of Cd, Cu, and Hg, Alopecurus pratensis of As and Phalaris arundinacea of Ni, Pb, and Zn. Relationships were weak between metal concentrations in plants and phytoavailable stocks in soil. As and Hg uptake seems to be enhanced on long submerged soils. Enrichments of Cd and Hg are linked to a special plant community composition. Grassland herbage sampled in July/August revealed higher concentrations of As (+122%), Hg (+124%), and Pb (+3723%) than in May. To limit harmful transfers into the food chain, low-lying terraces and flood channels revealing highest contaminations or phytoavailabilities should be excluded from mowing and grazing. - Soils in the Elbe river floodplains are highly polluted with metals and arsenic and a critical enrichment in the grassland herbage seems to be most likely in flood channels or within special plant species.

  18. Application of in-situ passive samplers for the investigation of the impacts of vegetated river beds on mineral N concentration gradients in the hyporheic zone

    Science.gov (United States)

    Ullah, S.; Zhang, H.; Heathwaite, L.; Lansdown, K.; Heppell, K.; Binley, A.; Trimmer, M.; Keenan, P.

    2010-12-01

    Conventional pore water sampling techniques have only a limitated capability to provide fine scale (cm or mm) depth resolution of chemical species associated with a ‘hotspot’ or a ‘hot event' in riverine hyporheic zones. To overcome this limitation, in-situ passive samplers (diffusive equilibrium in thin films-DET) were deployed in hyporheic sediments (0-30 cm depth) both under vegetated beds (dominated by Phragmites, spp.) and non-vegetated beds of a groundwater-fed river in Cumbria, UK. The riverbed environment consisted of coarse gravels and sandstone, requiring development of a new methodology for inserting the DET probes. The objectives were two-fold; 1) to explore the feasibility of DET deployment in hyporheic sediments dominated by gravels, and 2) to assess the impacts of vegetated beds on mineral N concentration gradients (cm scale resolution) to those under non-vegetated beds of the riverbed. The challenge of deploying DET in gravel bed sediments was met. Resulting information on fine scale gradients of mineral N and other redox sensitive species can improve our understanding of the dynamics of hyporheic mineral N species. According to the results, hyporheic sediments under vegetation exhibited significantly lower nitrate concentration gradients compared to non-vegetated hyporheic sediments. A dense piezometer network installed at the site showed that both locations possessed an upwelling potential at the time of DET deployment, and the amount of dissolved organic C was high in the hyporheic under reeds relative to the non-vegetated zones. These preliminary results suggest that vegetated beds in rivers could be effective in removing NO3 through denitrification and plant uptake besides rendering other ecosystem services such as habitat provision.

  19. Interactions between river stage and wetland vegetation detected with a Seasonality Index derived from LANDSAT images in the Apalachicola delta, Florida

    Science.gov (United States)

    Fagherazzi, S.; Toffolon, M.; la Cecilia, D.; Woodcock, C. E.

    2016-12-01

    The distribution of swamp floodplain vegetation and its evolution in the lower non-tidal reaches of the Apalachicola River, Florida USA, is mapped using Landsat Thematic Mapper and Enhanced Thematic Mapper Plus (TM/ETM+) images captured over a period of 29 years. A newly developed seasonality index (SI), the ratio of the NDVI in winter months to the summer months, shows that the hardwood swamp, dominated by bald cypress and water tupelo, is slowly replaced by bottomland hardwood forest. This forest shift is driven by lower water levels in the Apalachicola River in the last 30 years, and predominantly occurs in the transitional area between low floodplains and high river banks. A negative correlation between maximum summer NDVI and water levels in winter suggests the growth of more vigorous vegetation in the vicinity of sloughs during years with low river flow. A negative correlation with SI further indicates that these vegetation patches are possibly replaced by species typical of drier floodplain conditions.

  20. Vegetation development following stream/river restoration: more natural fluvial dynamics and morphology, return of aquatic and riparian plant species?

    Science.gov (United States)

    Soons, M. B.

    2012-04-01

    After centuries of human interventions in stream/river dynamics and morphology aimed at optimizing landscapes for agricultural and industrial purposes, new insights have inspired water managers to try and combine stream and river ecosystem functions with the conservation of biodiversity. Around the world, aquatic and riparian species have declined strongly due to pollution, destruction and fragmentation of their habitat, so that biodiversity conservation initiatives primarily focus on habitat restoration. In the past decades many stream and river restoration projects have been carried out and often hydrological dynamics and morphology have been restored to a more natural state. However, the successful restoration of aquatic and riparian habitats very often failed to result in restoration of their biodiversity. This lack of success from a biodiversity conservation perspective is usually attributed to 'dispersal limitation', meaning that the habitat may be restored, but species fail to reach the site and re-colonize it. Especially re-colonization by aquatic and riparian plant species is important, as such species function as ecosystem engineers: their presence alters fluvial dynamics and morphology, generates additional habitat heterogeneity and provides habitat and food for animal species. Following minor disturbances, re-colonization is often possible through locally remaining populations, by seeds in the seed bank or by surviving plant fragments. However, following major disturbances, colonization and establishment from other source populations are necessary. This usually occurs through dispersal of seeds (and in more aquatic species also by dispersal of vegetative fragments) into the restored wetland area. As dispersal occurs predominantly over short distances and source populations of aquatic and riparian species may be lacking in the surroundings, dispersal may be a limiting factor in the development of aquatic and riparian vegetation at a restored site. But

  1. Metals and arsenic in soils and corresponding vegetation at Central Elbe river floodplains (Germany).

    Science.gov (United States)

    Overesch, M; Rinklebe, J; Broll, G; Neue, H-U

    2007-02-01

    Floodplain soils at the Elbe river are frequently polluted with metals and arsenic. High contents of these pollutants were detected down to subsoil layers. NH4NO3-extractable (phytoavailable) Cd, Ni, and Zn were elevated in horizons with high acidity. Among five common floodplain plant species, Artemisia vulgaris showed highest concentrations of Cd, Cu, and Hg, Alopecurus pratensis of As and Phalaris arundinacea of Ni, Pb, and Zn. Relationships were weak between metal concentrations in plants and phytoavailable stocks in soil. As and Hg uptake seems to be enhanced on long submerged soils. Enrichments of Cd and Hg are linked to a special plant community composition. Grassland herbage sampled in July/August revealed higher concentrations of As (+122%), Hg (+124%), and Pb (+3723%) than in May. To limit harmful transfers into the food chain, low-lying terraces and flood channels revealing highest contaminations or phytoavailabilities should be excluded from mowing and grazing.

  2. Benthic metabolism and denitrification in a river reach: a comparison between vegetated and bare sediments

    Directory of Open Access Journals (Sweden)

    Pierluigi VIAROLI

    2009-02-01

    Full Text Available This study aims at comparing biogeochemical processes in a Vallisneria spiralis meadow and in unvegetated sediments in the upper reach of the Mincio River (Northern Italy. The main hypothesis of this work is that meadows of rooted macrophytes affect benthic metabolism, enhancing capacity to retain nutrients (assimilation and dissipate (denitrification nitrogen loadings. In order to highlight how plants affect benthic processes in the riverbed, oxygen, dissolved inorganic carbon (DIC, soluble reactive phosphorus (SRP and inorganic nitrogen fluxes, together with denitrification rates, were measured from February to November 2007 in intact cores collected from stands of V. spiralis and bare sediments. V. spiralis biomass, elemental composition and growth rates were concurrently measured. Macrophyte biomass ranged from 60 to 120 g m-2 (as dry matter; growth rates followed a seasonal pattern from 0.001 in winter up to 0.080 d-1 in summer. On an annual basis, the macrophyte meadow was autotrophic with net O2 production and dissolved inorganic carbon uptake, while the bare sediment was net heterotrophic. The concurrent N assimilation by macrophytes and losses through denitrification led to similar N uptake/dissipation rates, up to 2500 mmol m-2 y-1. Under the very high NO3 - concentrations of the Mincio River, the competition between primary production and denitrification processes was also avoided. A significant ammonium regeneration from sediments to the water column occurred in the V. spiralis meadow, where plant debris and particulate matter accumulated. Here, SRP was also released into the water column, whilst in the bare sediment SRP fluxes were close to zero. Overall, V. spiralis affected the benthic metabolism enhancing the ecosystem capacity to control nitrogen contamination. However, the actual N removal rates were not sufficient to mitigate the pollution discharge.

  3. NUMERICAL AND DIGITAL METHODS IN ANALYSIS OF SPACE-TIME CHANGES AND RENEWAL OF VEGETATION COVER RESOURCES IN THE CZARNA RIVER VALLEY

    Directory of Open Access Journals (Sweden)

    Grażyna Łaska

    2015-09-01

    Full Text Available The study aimed at evaluation of the current state and description of changes in plant communities in wetland habitats in the Czarna river valley and at recommendation of effective methods for the renewal of vegetation on the basis of detail analysis of its space-time changes. The methods applied included a compilation of field studies (inventory, cartographic study and phytosociological analyses, valorisation of nature, numerical syntaxonomy with the use of MVSP program (Cluster Analysis and PCA and digital methods GIS (Geomedia Professional 6.1. The field study of the vegetation cover of the Czarna river valley was performed in the years 2010–2011. The space-time analysis of changes in the vegetation cover and renewal of vegetation was made with the use of archive aerial photographs from 1966, topographic maps from 1982 and 2000 and orthophotomaps from 2011. The vegetation cover of the Czarna river valley was found to be composed of 12 plant communities representing 6 syntaxonomic classes, and to include sites of 8 protected species. The space-time analysis of the vegetation cover of the Czarna river valley, taking into account the changes in the forms of the valley use over the period 1966–2011, showed that the area occupied by forest communities in wetland habitats as a result of secondary succession has increased by 0.16 km2, so by 27% with respect to the area of 0.4406 km2 from 1966. Chronological changes in the vegetation cover over this area analysed on the basis of GIS and digital methods indicate that in the wet meadows in the valley studied the secondary succession leads to the reproduction of the potential forest communities that were growing there once in the past. The renewal of forestless greeneries in the Czarna river valley is related to changes in the use of the area realised by mowing and restoration of the earlier hydrological regime in the entire catchment area, changed by the network of channels and drainage ditches.

  4. The role of vegetated areas on fish assemblage of the Paraná River floodplain: effects of different hydrological conditions

    Directory of Open Access Journals (Sweden)

    Juan José Neiff

    hydrological conditions. Disturbances in the hydrological pulses could reduce the biodiversity by modifying the connectivity of the floodplain with the river channel. Conservation of these vegetated wetlands requires maintenance of actual width range of connectivity that provide diverse habitat along the time.

  5. Anthropogenic Disturbances Create a New Vegetation Toposequence in the Gatineau River Valley, Quebec

    Directory of Open Access Journals (Sweden)

    Jason Laflamme

    2016-10-01

    Full Text Available This study measured changes in forest composition that have occurred since the preindustrial era along the toposequence of the Gatineau River Valley, Quebec, Canada (5650 km2, based on survey records prior to colonization (1804–1864 and recent forest inventories (1982–2006. Changes in forest cover composition over time were found to be specific to toposequence position. Maple and red oak are now more frequent on upper toposequence positions (+26%, +21%, respectively, whereas yellow birch, eastern hemlock, and American beech declined markedly (−34% to −17%. Poplar is more frequent throughout the landscape, but particularly on mid-toposequence positions (+40%. In contrast, white pine, frequent on all toposequence positions in the preindustrial forest, is now confined to shallow and coarse-textured soils (−20%. The preindustrial forest types of the study area were mostly dominated by maple, yellow birch, and beech, with strong components of white pine, hemlock, and eastern white cedar, either as dominant or codominant species. In a context of ongoing anthropogenic disturbances and environmental changes, it is probably not possible to restore many of these types, except where targeted silvicultural interventions could increase the presence of certain species. The new forest types observed should be managed to ensure continuity of vital ecosystem services and functions as disturbance regimes evolve.

  6. Comparison of water consumption in two riparian vegetation communities along the central Platte River, Nebraska, 2008–09 and 2011

    Science.gov (United States)

    Hall, Brent M.; Rus, David L.

    2013-01-01

    The Platte River is a vital natural resource for the people, plants, and animals of Nebraska. A recent study quantified water use by riparian woodlands along central reaches of the Platte River, Nebraska, finding that water use was mainly regulated below maximum predicted levels. A comparative study was launched through a cooperative partnership between the U.S. Geological Survey, the Central Platte Natural Resources District, the Nebraska Department of Natural Resources, and the Nebraska Environmental Trust to compare water use of a riparian woodland with that of a grazed riparian grassland along the central Platte River. This report describes the results of the 3-year study by the U.S. Geological Survey to measure the evapotranspiration (ET) rates in the two riparian vegetation communities. Evapotranspiration was measured during 2008–09 and 2011 using the eddy-covariance method at a riparian woodland near Odessa, hereinafter referred to as the “woodland site,” and a riparian grassland pasture near Elm Creek, hereinafter referred to as the “grassland site.” Overall, annual ET totals at the grassland site were 90 percent of the annual ET measured at the woodland site, with averages of 653 millimeters (mm) and 726 mm, respectively. Evapotranspiration rates were similar at the grassland site and the woodland site during the spring and fall seasons, but at the woodland site ET rates were higher than those of the grassland site during the peak-growth summer months of June through August. These seasonal differences and the slightly lower ET rates at the grassland site were likely the result of differing plant communities, disturbance effects related to grazing and flooding, and climatic differences between the sites. The annual water balance was calculated for each site and indicated that the predominant factors in the water balance at both sites were ET and precipitation. Annual precipitation for the study period ranged from near to above the normal

  7. Risk of Illness with Salmonella due to Consumption of Raw Unwashed Vegetables Irrigated with Water from the Bogotá River.

    Science.gov (United States)

    Henao-Herreño, Laura X; López-Tamayo, Ana M; Ramos-Bonilla, Juan P; Haas, Charles N; Husserl, Johana

    2016-06-27

    The Bogotá River receives untreated wastewater from the city of Bogotá and many other towns. Downstream from Bogotá, water from the river is used for irrigation of crops. Concentrations of indicator organisms in the river are high, which is consistent with fecal contamination. To investigate the probability of illness due to exposure to enteric pathogens from the river, specifically Salmonella, we took water samples from the Bogotá River at six sampling locations in an area where untreated water from the river is used for irrigation of lettuce, broccoli, and cabbage. Salmonella concentrations were quantified by direct isolation and qPCR. Concentrations differed, depending on the quantification technique used, ranging between 10(7.7) and 10(9.9) number of copies of gene invA per L and 10(5.3) and 10(8.4) CFU/L, for qPCR and direct isolation, respectively. A quantitative microbial risk assessment model that estimates the daily risk of illness with Salmonella resulting from consuming raw unwashed vegetables irrigated with water from the Bogotá River was constructed using the Salmonella concentration data. The daily probability of illness from eating raw unwashed vegetables ranged between 0.62 and 0.85, 0.64 and 0.86, and 0.64 and 0.85 based on concentrations estimated by qPCR (0.47-0.85, 0.47-0.86, and 0.41-0.85 based on concentrations estimated by direct isolation) for lettuce, cabbage, and broccoli, respectively, which are all above the commonly propounded benchmark of 10(-4) per year. Results obtained in this study highlight the necessity for appropriate wastewater treatment in the region, and emphasize the importance of postharvest practices, such as washing, disinfecting, and cooking.

  8. The effect of submerged aquatic vegetation expansion on a declining turbidity trend in the Sacramento-San Joaquin River Delta

    Science.gov (United States)

    Hestir, E.L.; Schoellhamer, David H.; Jonathan Greenberg,; Morgan, Tara; Ustin, S.L.

    2016-01-01

    Submerged aquatic vegetation (SAV) has well-documented effects on water clarity. SAV beds can slow water movement and reduce bed shear stress, promoting sedimentation and reducing suspension. However, estuaries have multiple controls on turbidity that make it difficult to determine the effect of SAV on water clarity. In this study, we investigated the effect of primarily invasive SAV expansion on a concomitant decline in turbidity in the Sacramento-San Joaquin River Delta. The objective of this study was to separate the effects of decreasing sediment supply from the watershed from increasing SAV cover to determine the effect of SAV on the declining turbidity trend. SAV cover was determined by airborne hyperspectral remote sensing and turbidity data from long-term monitoring records. The turbidity trends were corrected for the declining sediment supply using suspended-sediment concentration data from a station immediately upstream of the Delta. We found a significant negative trend in turbidity from 1975 to 2008, and when we removed the sediment supply signal from the trend it was still significant and negative, indicating that a factor other than sediment supply was responsible for part of the turbidity decline. Turbidity monitoring stations with high rates of SAV expansion had steeper and more significant turbidity trends than those with low SAV cover. Our findings suggest that SAV is an important (but not sole) factor in the turbidity decline, and we estimate that 21–70 % of the total declining turbidity trend is due to SAV expansion.

  9. Fish abundances in shoreline habitats and submerged aquatic vegetation in a tidal freshwater embayment of the Potomac River.

    Science.gov (United States)

    Kraus, Richard T; Jones, R Christian

    2012-05-01

    Submerged aquatic vegetation (SAV) is considered an important habitat for juvenile and small forage fish species, but many long-term recruitment surveys do not effectively monitor fish communities in SAV. To better understand the impact of recent large increases of SAV on the fish community in tidal freshwater reaches of the Potomac River, we compared traditional seine sampling from shore with drop ring sampling of SAV beds (primarily Hydrilla) in a shallow water (depths, shoreline and SAV habitats in late summer of three different years (2007, 2008, and 2009). For the dominant species (Fundulus diaphanus, Lepomis macrochirus, Etheostoma olmstedi, Morone americana, Lepomis gibbosus, and Fundulus heteroclitus), density was nearly always higher in SAV, but overall, species richness was highest in shoreline habitats sampled with seines. Although historical monitoring of fish in Gunston Cove (and throughout Chesapeake Bay) is based upon seine sampling (and trawl sampling in deeper areas), the high densities of fish and larger areal extent of SAV indicated that complementary sampling of SAV habitats would produce more accurate trends in abundances of common species. Because drop ring samples cover much less area than seines and may miss rare species, a combination of methods that includes seine sampling is needed for biodiversity assessment. The resurgence of SAV in tidal freshwater signifies improving water quality, and methods we evaluated here support improved inferences about population trends and fish community structure as indicators of ecosystem condition.

  10. Extraction of the vegetation fraction based on a stepwise spectral mixture analysis for the central and eastern area of source region of Yangtze, Yellow and Lantsang Rivers

    Science.gov (United States)

    Li, Xiaoxue; An, Ru; Qu, Chunmei; Yang, Renmin; Gong, Tianyu; Wu, Hong; Lu, Ling; Liu, Yingying; Liang, Xin

    2011-10-01

    Vegetation cover is an important parameter used in monitoring ecological changes of the source region of Yangtze, Yellow and Lantsang Rivers and understanding human activities. Thus, how to extract the large area's vegetation fraction quickly effectively is an open question. The traditional linear spectral mixture analysis (LSMA) assumes that the spectral reflectance is a mixture of several fixed endmember spectral values, which ignores considerable within-class variability. However, multiple endmember spectral mixture analysis (MESMA) overcomes the disadvantage by allowing the number and types to vary on a per-pixel basis. This paper proposes a stepwise spectral mixture analysis (SSMA) containing two steps of MESMA and adding the endmember fraction rationality rule in each step. The aim of the first step is to detect the pixels that didn't contain vegetation information at all and these pixels would be masked out. In the second step, MESMA is used to unmix the pixels only reserved in previous process. The results show that SSMA is more accurate than LSMA in extracting the vegetation fraction for the Three-Rivers. This means that SSMA is a good substitute for LSMA in studies on ecological changes. The concept of SSMA also can be applied for other large study areas.

  11. Coupling LiDAR and thermal imagery to model the effects of riparian vegetation shade and groundwater inputs on summer river temperature.

    Science.gov (United States)

    Wawrzyniak, Vincent; Allemand, Pascal; Bailly, Sarah; Lejot, Jérôme; Piégay, Hervé

    2017-03-16

    In the context of global warming, it is important to understand the drivers controlling river temperature in order to mitigate temperature increases. A modeling approach can be useful for quantifying the respective importance of the different drivers, notably groundwater inputs and riparian shading which are potentially critical for reducing summer temperature. In this study, we use a one-dimensional deterministic model to predict summer water temperature at an hourly time step over a 21km reach of the lower Ain River (France). This sinuous gravel-bed river undergoes summer temperature increase with potential impacts on salmonid populations. The model considers heat fluxes at the water-air interface, attenuation of solar radiation by riparian forest, groundwater inputs and hydraulic characteristics of the river. Modeling is performed over two periods of five days during the summers 2010 and 2011. River properties are obtained from hydraulic modeling based on cross-section profiles and water level surveys. We model shadows of the vegetation on the river surface using LiDAR data. Groundwater inputs are determined using airborne thermal infrared (TIR) images and hydrological data. Results indicate that vegetation and groundwater inputs can mitigate high water temperatures during summer. Riparian shading effect is fairly similar between the two periods (-0.26±0.12°C and -0.31±0.18°C). Groundwater input cooling is variable between the two studied periods: when groundwater discharge represents 16% of the river discharge, it cools the river down by 0.68±0.13°C while the effect is very low (0.11±0.01°C) when the groundwater discharge contributes only 2% to the discharge. The effect of shading varies through the day: low in the morning and high during the afternoon and the evening whereas those induced by groundwater inputs is more constant through the day. Overall, the effect of riparian vegetation and groundwater inputs represents about 10% in 2010 and 24% in 2011

  12. A GIS TOOL TO EVALUATE THE SPATIAL EVOLUTION OF HYDRO-THERMIC FEATURES DURING GROWING SEASON OF VEGETABLE CROPS IN ELBE RIVER LOWLAND (POLABI

    Directory of Open Access Journals (Sweden)

    VERA POTOP

    2012-11-01

    Full Text Available A GIS tool to evaluate the spatial evolution of hydro-thermic features during growing season of vegetable crops in Elbe River lowland (Polabi. This article presents the results of the first study on combined mezoclimatological, microclimatological and topographical tools for evaluating precision farming in the growth of vegetable crops in the Elbe River lowland (Polabi region from the Czech Republic. We assess the variability of basically climatological characteristics in relation to topographic characteristics at the regional (Polabi and local (agricultural farm scales. At regional scale, interpolation approach is based on local linear regression and universal kriging interpolation. At local scale, two conventional interpolation methods, spline and local ordinary kriging with a Gaussian model variance across the fields, were applied. The local spline interpolators have been used in developing digital elevation models (DEMs and to determine the slope angle inclination of vegetable fields. The DEMs of the vegetable crops fields was developed at a 10 m x 10 m resolution based on elevation data collected in the field by a hand-held RTK- Global Positioning System receiver. This tool allowed the distinction of microclimatic conditions that produce altitude-slope-related patterns of the spatial-temporal distribution of the basic meteorological elements during growing season of vegetable crops. The effect of slope on diurnal extreme temperatures in the vegetable cropped field conditions was more pronounced than that of elevation. Accordingly to developed maps, the warmest and longest duration of sunshine, and the least precipitation totals during growing season occurred in the middle part of Polabi.

  13. Estimating Vegetation Primary Production in the Heihe River Basin of China with Multi-Source and Multi-Scale Data.

    Science.gov (United States)

    Cui, Tianxiang; Wang, Yujie; Sun, Rui; Qiao, Chen; Fan, Wenjie; Jiang, Guoqing; Hao, Lvyuan; Zhang, Lei

    2016-01-01

    Estimating gross primary production (GPP) and net primary production (NPP) are significant important in studying carbon cycles. Using models driven by multi-source and multi-scale data is a promising approach to estimate GPP and NPP at regional and global scales. With a focus on data that are openly accessible, this paper presents a GPP and NPP model driven by remotely sensed data and meteorological data with spatial resolutions varying from 30 m to 0.25 degree and temporal resolutions ranging from 3 hours to 1 month, by integrating remote sensing techniques and eco-physiological process theories. Our model is also designed as part of the Multi-source data Synergized Quantitative (MuSyQ) Remote Sensing Production System. In the presented MuSyQ-NPP algorithm, daily GPP for a 10-day period was calculated as a product of incident photosynthetically active radiation (PAR) and its fraction absorbed by vegetation (FPAR) using a light use efficiency (LUE) model. The autotrophic respiration (Ra) was determined using eco-physiological process theories and the daily NPP was obtained as the balance between GPP and Ra. To test its feasibility at regional scales, our model was performed in an arid and semi-arid region of Heihe River Basin, China to generate daily GPP and NPP during the growing season of 2012. The results indicated that both GPP and NPP exhibit clear spatial and temporal patterns in their distribution over Heihe River Basin during the growing season due to the temperature, water and solar influx conditions. After validated against ground-based measurements, MODIS GPP product (MOD17A2H) and results reported in recent literature, we found the MuSyQ-NPP algorithm could yield an RMSE of 2.973 gC m(-2) d(-1) and an R of 0.842 when compared with ground-based GPP while an RMSE of 8.010 gC m(-2) d(-1) and an R of 0.682 can be achieved for MODIS GPP, the estimated NPP values were also well within the range of previous literature, which proved the reliability of our

  14. The effect of permafrost, vegetation, and lithology on Mg and Si isotope composition of the Yenisey River and its tributaries at the end of the spring flood

    Science.gov (United States)

    Mavromatis, Vasileios; Rinder, Thomas; Prokushkin, Anatoly S.; Pokrovsky, Oleg S.; Korets, Mikhail A.; Chmeleff, Jérôme; Oelkers, Eric H.

    2016-10-01

    This work focuses on the behavior of the stable Mg and Si isotope compositions of the largest Arctic river, the Yenisey River and 28 of its major and minor tributaries during the spring flood period. Samples were collected along a 1500 km latitudinal profile covering a wide range of permafrost, lithology, and vegetation. Despite significant contrasts in the main physico-geographical, climate, and lithological parameters of the watersheds, the isotope composition of both dissolved Mg and Si was found to be only weakly influenced by the degree of the permafrost coverage, type of vegetation (forest vs. tundra), and lithology (granites, basalts, carbonates or terrigenous rocks). This observation is generally consistent with the lack of chemical uptake of Mg and Si by soil mineral formation and vegetation during the early spring. The radiogenic Sr isotope composition of the Yenisey and its tributaries varied within a narrow range (0.708 ⩽ 87Sr/86Sr ⩽ 0.711) reflecting the dominance of Phanerozoic rock weathering and/or atmospheric deposition on these compositions. The Mg and Si isotopic compositions of riverine samples reflect two main processes with distinct isotopic signatures. First, isotopically heavier Mg (δ26Mg = -1.0 ± 0.2‰) and isotopically lighter Si (δ30Si = 1.0 ± 0.25‰) are added to the waters by river suspended matter dissolution and leaching from vegetation biomass/topsoil litter. Second, isotopically lighter Mg (δ26Mg = -1.5 to -1.75‰) and isotopically heavier Si (δ30Si = 1.75-2.0‰) are delivered to the Yenisey's tributaries from deep underground water feeding the rivers via taliks. This lighter Mg and heavier Si isotopic composition is interpreted to originate from Precambrian dolomite dissolution and aluminosilicate dissolution coupled with authigenic mineral precipitation, respectively, in deep underground water reservoirs. Taking account of the isotopic composition evolution over the course of the year established earlier on mono

  15. Composition of shrimp populations (Crustacea: Decapoda in non-vegetated areas of two river islands in a Brazilian Amazon estuary

    Directory of Open Access Journals (Sweden)

    Priscila Sousa Vilela da Nóbrega

    2013-12-01

    Full Text Available This study investigates the shrimp found in non-vegetated areas of an estuary of the Amazon River. We ascertained the input of juveniles, species' biometrics and the influence of environmental factors on the abundance of species. The samples were collected monthly, from August 2006 to July 2007, in two places in the estuary, each next to an island. For collecting, we used a manual trawl to perform three hauls per month, totaling 36 samples per site. The abundance of shrimps was estimated as a function of the density of specimens per unit area. We used the Spearman's correlation to test the hypothesis that there is significant correlation between the average of the environmental variables measured and variations in shrimp density. The Kruskal-Wallis and the Mann-Whitney tests showed that there were significant differences in environment factors (temperature and salinity among the months and sites. We obtained 6,091 shrimps, from which 5,231 (85.88% were caught off the Arapiranga Island and 860 (14.12% off the Mosqueiro Island, Palaemonidae and Penaeidae were the only families recorded. Five species were collected: Macrobrachium amazonicum (Heller, 1862, Macrobrachium surinamicum Holthuis, 1948, Macrobrachium carcinus (Linnaeus, 1758, Macrobrachium rosenbergii (De Man, 1879, and Farfantepenaeus subtilis (Pérez-Farfante, 1967. The latter (pink shrimp was found for the first time in oligohaline environments (0-8. Macrobrachium amazonicum was the most abundant species. The recruitment of M. amazonicum juveniles was continuous throughout the year. The population of M. surinamicum was composed by juveniles and adults and that of F. subtilis exclusively by juveniles. The environmental factors analyzed were variable throughout the year and seem to explain the patterns of shrimp species occurrence in the region, the variation in their abundance and juvenile recruitment.

  16. Variations in annual water-energy balance and their correlations with vegetation and soil moisture dynamics: A case study in the Wei River Basin, China

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Shengzhi; Huang, Qiang; Leng, Guoyong; Zhao, Menglong; Meng, Erhao

    2017-03-01

    It is of importance to investigate watershed water-energy balance variations and to explore their correlations with vegetation and soil moisture dynamics, which helps better understand the interplays between underlying surface dynamics and the terrestrial water cycle. The heuristic segmentation method was adopted to identify change points in the parameter to series in Fu's equation belonging to the Budyko framework in the Wei River Basin (WRB) and its sub-basins aiming to examine the validity of stationary assumptions. Additionally, the cross wavelet analysis was applied to explore the correlations between vegetation and soil moisture dynamics and to variations. Results indicated that (1) the omega variations in the WRB are significant, with some change points identified except for the sub-basin above Zhangjiashan, implying that the stationarity of omega series in the WRB is invalid except for the sub-basin above Zhangjiashan; (2) the correlations between soil moisture series and to series are weaker than those between Normalized Difference Vegetation Index (NDVI) series and omega series; (3) vegetation dynamics show significantly negative correlations with omega variations in 1983-2003 with a 4-8 year signal in the whole WRB, and both vegetation and soil moisture dynamics exert strong impacts on the parameter omega changes. This study helps understanding the interactions between underlying land surface dynamics and watershed water-energy balance. (C) 2017 Elsevier B.V. All rights reserved.

  17. 嘉陵江流域植被覆盖时空变化特征%TEMPORAL AND SPATIAL VARIATION OF VEGETATION IN JIALING RIVER BASIN

    Institute of Scientific and Technical Information of China (English)

    刘洪鹄; 张平仓; 刘宪春; 信忠保; 岑奕

    2011-01-01

    Normal Difference Veget ation Index (NDVI) can represent the ground vegetation to some extent,which reflects the change of environment and global change. Currently, studies on vegetation change are mainly distributed in Shannxi Province,Gansu Province,Xinjiang Province etc. However,there are relatively few studies on temporal and spatial variation of vegetation and its impact factors in Jialing River Basin.Thus, with the support of GIS software,this study was to explore the temporal and spatial variation of vegetation and analyze the impact factors in Jialing River Basin using the GIMMS NDVI data and the linear correlation analysis method. The results are as follows: (1) In 1982~2006,the average NDVI in the whole basin gradually increased year by year. This was same with the other area,but their slope of linear regression equation was different. (2) The vegetation in Jialing River Basin was better than Loess Plateau and Northwest China. Spatial difference of vegetation was significant and NDVI in the southern district was less than northern district. (3) Spatial difference of vegetation variation was also significant. But slope of linear regression equation in the southern district was greater than northern district. (4) Spatial distribution of NDVI and its change in 1982~2006 was related to human activities and climate change. Based on these analyses, the results indicate that human activities such as soil and water conservation measures in the upper reach of the Yangtze River and climate change makes vegetation and environment better.%归一化植被指数(Norreal Difference Vegetation Index,NDVI)能够反映植被的繁茂程度,可用来揭示环境的演化,并且能在全球变化研究中起到"指示器"的作用.目前利用NDVI研究植被变化多集中于陕西、甘肃、新疆等地区,对嘉陵江流域的植被变化趋势及其影响因素研究很少.利用线性相关分析方法分析GIMMS NDVI数据,借助于地理信息系统软件,分析

  18. Health of native riparian vegetation and its relation to hydrologic conditions along the Mojave River, southern California

    Science.gov (United States)

    Lines, Gregory C.

    1999-01-01

    The health of native riparian vegetation and its relation to hydrologic conditions were studied along the Mojave River mainly during the growing seasons of 1997 and 1998. The study concentrated on cottonwood?willow woodlands (predominantly Populus fremontii and Salix gooddingii) and mesquite bosques (predominantly Prosopis glandulosa). Tree-growth characteristics were measured at 16 cottonwood?willow woodland sites and at 3 mesquite bosque sites. Density of live and dead trees, tree diameter and height, canopy density, live-crown volume, leaf-water potential, leaf-area index, mortality, and reproduction were measured or noted at each site. The sites included healthy and reproducing woodlands and bosques, stressed woodlands and bosques with no reproduction, and woodlands and bosques with high mortality. Tree roots were studied at seven sites to determine the vertical distribution of the root system and their relation to the water table at healthy, stressed, and high-mortality cottonwood?willow woodlands. In the six trenches that were dug for this study in May 1997, no cottonwood roots were observed that reached the water table. The root systems of healthy trees typically ended 1 to 2 feet above the water table. At sites with high mortality, the main root mass was commonly 7 to 8 feet above the water table. Water-table depth was monitored at each of the study sites. In addition, volumetric soil moisture and soil-water potential were monitored at varying depths at three cottonwood?willow woodland study sites and at two mesquite bosque sites. Ground, soil, river, lake, and plant (xylem sap) water were analyzed for concentrations of stable hydrogen and oxygen isotopes to determine the source of water used by the trees. On the basis of the root-distribution, soil- and leaf-water potential, and isotope data, it was concluded that cottonwood, willow, and mesquite trees mainly rely on ground water for their perennial sustained supply of water. The trees mainly utilize

  19. Rivers through time: historical changes in the riparian vegetation of the semi-arid, winter rainfall region of South Africa in response to climate and land use.

    Science.gov (United States)

    Hoffman, M Timm; Rohde, Richard Frederick

    2011-01-01

    This paper examines how the riparian vegetation of perennial and ephemeral rivers systems in the semi-arid, winter rainfall region of South Africa has changed over time. Using an environmental history approach we assess the extent of change in plant cover at 32 sites using repeat photographs that cover a time span of 36-113 years. The results indicate that in the majority of sites there has been a significant increase in cover of riparian vegetation in both the channel beds and adjacent floodplain environments. The most important species to have increased in cover across the region is Acacia karroo. We interpret the findings in the context of historical changes in climate and land use practices. Damage to riparian vegetation caused by mega-herbivores probably ceased sometime during the early 19th century as did scouring events related to large floods that occurred at regular intervals from the 15th to early 20th centuries. Extensive cutting of riparian vegetation for charcoal and firewood has also declined over the last 150 years. Changes in the grazing history as well as increased abstraction and dam building along perennial rivers in the region also account for some of the changes observed in riparian vegetation during the second half of the 20th century. Predictions of climate change related to global warming anticipate increased drought events with the subsequent loss of species and habitats in the study area. The evidence presented here suggests that an awareness of the region's historical ecology should be considered more carefully in the modelling and formulation of future climate change predictions as well as in the understanding of climate change impacts over time frames of decades and centuries.

  20. CHANGES IN 137 CS CONCENTRATIONS IN SOIL AND VEGETATION ON THE FLOODPLAIN OF THE SAVANNAH RIVER OVER A 30 YEAR PERIOD

    Energy Technology Data Exchange (ETDEWEB)

    Paller, M.; Jannik, T.; Fledderman, P.

    2007-12-12

    {sup 137}Cs released during 1954-1974 from nuclear production reactors on the Savannah River Site, a US Department of Energy nuclear materials production site in South Carolina, contaminated a portion of the Savannah River floodplain known as Creek Plantation. {sup 137}Cs activity concentrations have been measured in Creek Plantation since 1974 making it possible to calculate effective half-lives for {sup 137}Cs in soil and vegetation and assess the spatial distribution of contaminants on the floodplain. Activity concentrations in soil and vegetation were higher near the center of the floodplain than near the edges as a result of frequent inundation coupled with the presence of low areas that trapped contaminated sediments. {sup 137}Cs activity was highest near the soil surface, but depth related differences diminished with time as a likely result of downward diffusion or leaching. Activity concentrations in vegetation were significantly related to concentrations in soil. The plant to soil concentration ratio (dry weight) averaged 0.49 and exhibited a slight but significant tendency to decrease with time. The effective half-lives for {sup 137}Cs in shallow (0-7.6 cm) soil and in vegetation were 14.9 (95% CI = 12.5-17.3) years and 11.6 (95% CI = 9.1-14.1) years, respectively, and rates of {sup 137}Cs removal from shallow soil and vegetation did not differ significantly among sampling locations. Potential health risks on the Creek Plantation floodplain have declined more rapidly than expected on the basis of radioactive decay alone because of the relatively short effective half-life of {sup 137}Cs.

  1. Groundwater–surface water interactions, vegetation dependencies and implications for water resources management in the semi-arid Hailiutu River catchment, China – a synthesis

    Directory of Open Access Journals (Sweden)

    Y. Zhou

    2013-07-01

    Full Text Available During the last decades, large-scale land use changes took place in the Hailiutu River catchment, a semi-arid area in northwest China. These changes had significant impacts on the water resources in the area. Insights into groundwater and surface water interactions and vegetation-water dependencies help to understand these impacts and formulate sustainable water resources management policies. In this study, groundwater and surface water interactions were identified using the baseflow index at the catchment scale, and hydraulic and water temperature methods as well as event hydrograph separation techniques at the sub-catchment scale. The results show that almost 90% of the river discharge consists of groundwater. Vegetation dependencies on groundwater were analysed from the relationship between the Normalized Difference Vegetation Index (NDVI and groundwater depth at the catchment scale and along an ecohydrogeological cross-section, and by measuring the sap flow of different plants, soil water contents and groundwater levels at different research sites. The results show that all vegetation types, i.e. trees (willow (Salix matsudana and poplar (Populus simonii, bushes (salix – Salix psammophila, and agricultural crops (maize – Zea mays, depend largely on groundwater as the source for transpiration. The comparative analysis indicates that maize crops use the largest amount of water, followed by poplar trees, salix bushes, and willow trees. For sustainable water use with the objective of satisfying the water demand for socio-economical development and to prevent desertification and ecological impacts on streams, more water-use-efficient crops such as sorghum, barley or millet should be promoted to reduce the consumptive water use. Willow trees should be used as wind-breaks in croplands and along roads, and drought-resistant and less water-use intensive plants (for instance native bushes should be used to vegetate sand dunes.

  2. Wide-area estimates of evapotranspiration by red gum (Eucalyptus camaldulensis) and associated vegetation in the Murray-Darling River Basin, Australia

    Science.gov (United States)

    Nagler, Pamela L.; Doody, Tanya M.; Glenn, Edward P.; Jarchow, Christopher J.; Barreto-Munoz, Armando; Didan, Kamel

    2016-01-01

    Floodplain red gum forests (Eucalyptus camaldulensis plus associated grasses, reeds and sedges) are sites of high biodiversity in otherwise arid regions of southeastern Australia. They depend on periodic floods from rivers, but dams and diversions have reduced flood frequencies and volumes, leading to deterioration of trees and associated biota. There is a need to determine their water requirements so environmental flows can be administered to maintain or restore the forests. Their water requirements include the frequency and extent of overbank flooding, which recharges the floodplain soils with water, as well as the actual amount of water consumed in evapotranspiration (ET). We estimated the flooding requirements and ET for a 38 134 ha area of red gum forest fed by the Murrumbidgee River in Yanga National Park, New South Wales. ET was estimated by three methods: sap flux sensors placed in individual trees; a remote sensing method based on the Enhanced Vegetation Index from MODIS satellite imagery and a water balance method based on differences between river flows into and out of the forest. The methods gave comparable estimates yet covered different spatial and temporal scales. We estimated flood frequency and volume requirements by comparing Normalized Difference Vegetation Index values from Landsat images with flood history from 1995 to 2014, which included both wet periods and dry periods. ET during wet years is about 50% of potential ET but is much less in dry years because of the trees' ability to control stomatal conductance. Based on our analyses plus other studies, red gum trees at this location require environmental flows of 2000 GL yr−1 every other year, with peak flows of 20 000 ML d−1, to produce flooding sufficient to keep them in good condition. However, only about 120–200 GL yr−1 of river water is consumed in ET, with the remainder flowing out of the forest where it enters the Murray River system.

  3. Impact of urban contamination of the La Paz River basin on thermotolerant coliform density and occurrence of multiple antibiotic resistant enteric pathogens in river water, irrigated soil and fresh vegetables.

    Science.gov (United States)

    Poma, Violeta; Mamani, Nataniel; Iñiguez, Volga

    2016-01-01

    La Paz River in Andean highlands is heavily polluted with urban run-off and further contaminates agricultural lowlands and downstream waters at the Amazon watershed. Agricultural produce at this region is the main source of vegetables for the major Andean cities of La Paz and El Alto. We conducted a 1 year study, to evaluate microbial quality parameters and occurrence of multiple enteropathogenic bacteria (Enterohemorrhagic E. coli-EHEC, Enteroinvasive E. coli or Shigella-EIEC/Shigella, Enteroaggregative E. coli-EAEC, Enteropathogenic E. coli-EPEC Enterotoxigenic E. coli-ETEC and Salmonella) and its resistance to 11 antibiotics. Four sampling locations were selected: a fresh mountain water reservoir (un-impacted, site 1) and downstream sites receiving wastewater discharges (impacted, sites 2-4). River water (sites 1-4, N = 48), and soil and vegetable samples (site 3, N = 24) were collected during dry (April-September) and rainy seasons (October-March). Throughout the study, thermotolerant coliform density values at impacted sites greatly exceeded the guidelines for recreational and agricultural water uses. Seasonal differences were found for thermotolerant coliform density during dry season in water samples nearby a populated and hospital compound area. In contrast to the un-impacted site, where none of the tested enteropathogens were found, 100 % of surface water, 83 % of soil and 67 % of vegetable samples at impacted sites, were contaminated with at least one enteropathogen, being ETEC and Salmonella the most frequently found. ETEC isolates displayed different patterns of toxin genes among sites. The occurrence of enteropathogens was associated with the thermotolerant coliform density. At impacted sites, multiple enteropathogens were frequently found during rainy season. Among isolated enteropathogens, 50 % were resistant to at least two antibiotics, with resistance to ampicillin, nalidixic acid, trimethoprim-sulfamethoxazole and tetracycline commonly

  4. Arboreous vegetation of an alluvial riparian forest and their soil relations: Porto Rico island, Paraná river, Brazil

    Directory of Open Access Journals (Sweden)

    João Batista Campos

    2002-06-01

    Full Text Available The dynamics of alluvial deposits in floodplains forms islands and sandbanks. Deposits frequently accumulate at the river margins and on islands with consequent side growths. One of these sandbanks which started to form in 1952 annexed an area of 12.4ha to the Porto Rico island (53º15’W and 22º45’S. At present a forest fragment of approximately 2.0 ha exists in this place. The structural analysis of arboreous vegetation of this fragment showed a floristic gradient related to the physical and chemical variations of the substratum. High density of pioneer species associated to the absence of recruitment of new individuals of these and other successional categories indicated that the forest was impaired in its succession process. This fact could be associated with constant disturbances caused by cattle in the area.A dinâmica de deposições aluviais em planícies de inundação proporciona a formação de ilhas e barras (bancos de areia, que muitas vezes agregam-se às margens dos rios ou ilhas propiciando o seu crescimento lateral. Uma dessas barras, com início de formação a partir de 1952, agregou a ilha Porto Rico (53º15’W e 22º45’S uma área de 12,40ha, onde existe, atualmente, um fragmento florestal de aproximadamente 2,0ha. A análise estrutural da vegetação arbórea desse fragmento mostra a presença de um gradiente florístico relacionado às variações físicas e químicas do substrato. A elevada densidade de espécies pioneiras, associada a ausência de recrutamento de novos indivíduos, dessas e de outras categorias sucessionais, indicam que esta floresta está limitada em seu processo de sucessão, podendo, este fato, estar associado às constantes perturbações provocada pela presença de gado na área.

  5. Spatial and temporal relationships between the invasive snail Bithynia tentaculata and submersed aquatic vegetation in Pool 8 of the Upper Mississippi River

    Science.gov (United States)

    Weeks, Alicia M.; DeJager, Nathan R.; Haro, Roger J.; Sandland, Greg J.

    2017-01-01

    Bithynia tentaculata is an invasive snail that was first reported in Lake Michigan in 1871 and has since spread throughout a number of freshwater systems of the USA. This invasion has been extremely problematic in the Upper Mississippi River as the snails serve as intermediate hosts for several trematode parasites that have been associated with waterfowl mortality in the region. This study was designed to assess the abundance and distribution of B. tentaculata relative to submersed aquatic vegetation as macrophytes provide important nesting and food resources for migrating waterfowl. Temporal changes in both vegetation and snail densities were compared between 2007 and 2015. Between these years, B. tentaculata densities have nearly quadrupled despite minor changes in vegetation abundance, distribution and composition. Understanding the spatial distribution of B. tentaculata in relation to other habitat features, including submersed vegetation, and quantifying any further changes in the abundance and distribution of B. tentaculata over time will be important for better identifying areas of risk for disease transmission to waterfowl.

  6. 基于MODIS/NDVI的新疆伊犁河谷植被变化%Vegetation dynamics in Ili River valley of Xinjiang based on MODIS/NDVI

    Institute of Scientific and Technical Information of China (English)

    闫俊杰; 乔木; 周宏飞; 周生斌; 卢磊; 宋鹏

    2013-01-01

    利用2000-2010年16d合成的MODIS/NDVI数据,结合植被异常指数、趋势线分析和Hurst 指数等分析方法,对新疆伊犁河谷植被覆盖的时空变化特征进行了分析.结果表明:(1)伊犁河谷内植被覆盖随海拔增高而先增加后减小,最高植被覆盖区位于2000~2 500m的高程带;2000-2010年伊犁河谷各高程带内植被覆盖整体下降趋势明显,但海拔低于1000m的高程带除外.(2)受干湿环境影响,伊犁河谷全区平均被植异常指数最高值出现在降水最多的2002年,最低值出现在降水最少的2008年,但不同区域植被异常指数的变化存在较大差异.(3)伊犁河谷内植被覆盖增加和减小的区域分别占总面积的4.09%和19.34%,增加区域主要位于伊犁河两岸的平原区,减小区域主要位于乌孙山两端以及伊犁河谷周围海拔2000m左右的低山区域;变标度极差分析结果表明,伊犁河谷内植被覆盖年际变化呈现很强的持续性,未来一定时间内将保持现有变化趋势不变.%16-day composite data set of normalized difference vegetation index (NDVI) from an moderate-resolu-tion imaging spectroradiometer(MODIS) was used to capture essential feature of temporal and spatial vegetation variability in Ili River valley of Xinjiang during the 2000-2010 period.Various statistical analyses involving vegetation anomaly index,linear regression analysis and Hurst index were applied.Examination shows as follows:(1) Vegetation cover of Ili River Valley increases firstly and then decreases as altitude increases,with highest vegetation cover located in the area with the altitude from 2 000 to 2 500 m.Generally,vegetation cover of different elevation zones of Ili River valley followed a decreasing trend during the period of 2000-2010,not including the areas located below 1 000 m above the sea level.(2)As vegetation anomaly index is subject to humidity of the air,so the highest spatially averaged vegetation anomaly index value

  7. Flooding ecology of voles, mice and shrews: the importance of geomorphological and vegetational heterogeneity in river floodplains

    NARCIS (Netherlands)

    Wijnhoven, S.; Velde, G. van der; Leuven, R.S.E.W.; Smits, A.J.M.

    2005-01-01

    Since voles, mice and shrews are important animals in food chains of river floodplains, there is a need for data on their spatial and temporal distribution in periodically flooded areas. During a live trapping study between two successive floods in an embanked river floodplain, the ’Afferdensche en

  8. Vegetation - Medium Scale Central Valley Riparian Vegetation and Land Use, 2011 [ds723

    Data.gov (United States)

    California Department of Resources — Geodatabase (SDE) feature class containing map of vegetation along mainstem rivers and major tributaries (including ancillary natural and semi-natural vegetation)...

  9. Development of a high-resolution binational vegetation map of the Santa Cruz River riparian corridor and surrounding watershed, southern Arizona and northern Sonora, Mexico

    Science.gov (United States)

    Wallace, Cynthia S.A.; Villarreal, Miguel L.; Norman, Laura M.

    2011-01-01

    This report summarizes the development of a binational vegetation map developed for the Santa Cruz Watershed, which straddles the southern border of Arizona and the northern border of Sonora, Mexico. The map was created as an environmental input to the Santa Cruz Watershed Ecosystem Portfolio Model (SCWEPM) that is being created by the U.S. Geological Survey for the watershed. The SCWEPM is a map-based multicriteria evaluation tool that allows stakeholders to explore tradeoffs between valued ecosystem services at multiple scales within a participatory decision-making process. Maps related to vegetation type and are needed for use in modeling wildlife habitat and other ecosystem services. Although detailed vegetation maps existed for the U.S. side of the border, there was a lack of consistent data for the Santa Cruz Watershed in Mexico. We produced a binational vegetation classification of the Santa Cruz River riparian habitat and watershed vegetation based on NatureServe Terrestrial Ecological Systems (TES) units using Classification And Regression Tree (CART) modeling. Environmental layers used as predictor data were derived from a seasonal set of Landsat Thematic Mapper (TM) images (spring, summer, and fall) and from a 30-meter digital-elevation-model (DEM) grid. Because both sources of environmental data are seamless across the international border, they are particularly suited to this binational modeling effort. Training data were compiled from existing field data for the riparian corridor and data collected by the NM-GAP (New Mexico Gap Analysis Project) team for the original Southwest Regional Gap Analysis Project (SWReGAP) modeling effort. Additional training data were collected from core areas of the SWReGAP classification itself, allowing the extrapolation of the SWReGAP mapping into the Mexican portion of the watershed without collecting additional training data.

  10. Investigations of the vegetation along the river Laagen in connection with expansion of the Lower Vinstra Power Station; Vegetasjonsundersoekelser i Laagen i forbindelse med utvidelse av Nedre Vinstra kraftverk

    Energy Technology Data Exchange (ETDEWEB)

    Brandrud, T.E.; Mjelde, M [Norsk Inst. for Vannforskning, Oslo (Norway); Bendiksen, E. [Norsk Inst. for Naturforskning, Trondheim (Norway)

    1996-05-01

    To qualify for a licence to expand, the Norwegian hydroelectric power plant Lower Vinstra Power Station had to perform botanical investigations of the aquatic and riverside vegetation (riparian vegetation) along the affected part of the river Gudbrandsdalslaagen, between Harpefoss and Faavang. The investigations took place in 1990-1994 and is described in the present report. The riverside vegetation was stable throughout the entire period, overgrowing weakly. The aquatic vegetation exibited greater fluctuations, including episodic decline in unstable areas. Aquatic vegetation declined and vanished in areas with large as well as with little diurnal variation of the water level, which is primarily due to flooding episods. Erosion or essential changes in aquatic or riverside vegetation caused by increased diurnal regulation (HEP regulations) cannot be demonstrated with any great probability. 13 refs., 14 figs., 8 tabs.

  11. Vegetation dynamics and its driving forces from climate change and human activities in the Three-River Source Region, China from 1982 to 2012

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ying; Zhang, Chaobin; Wang, Zhaoqi; Chen, Yizhao; Gang, Chengcheng [School of Life Science, Nanjing University, Xianlin Road 163, Qixia District, Nanjing, 210046 (China); An, Ru [School of Earth Science and Engineering, Hohai University, Xikang Road 129, Nanjing, 210098 (China); Li, Jianlong, E-mail: lijianlongnju@163.com [School of Life Science, Nanjing University, Xianlin Road 163, Qixia District, Nanjing, 210046 (China)

    2016-09-01

    The Three-River Source Region (TRSR), a region with key importance to the ecological security of China, has undergone climate changes and a shift in human activities driven by a series of ecological restoration projects in recent decades. To reveal the spatiotemporal dynamics of vegetation dynamics and calculate the contributions of driving factors in the TRSR across different periods from 1982 to 2012, net primary productivity (NPP) estimated using the Carnegie–Ames–Stanford approach model was used to assess the status of vegetation. The actual effects of different climatic variation trends on interannual variation in NPP were analyzed. Furthermore, the relationships of NPP with different climate factors and human activities were analyzed quantitatively. Results showed the following: from 1982 to 2012, the average NPP in the study area was 187.37 g cm{sup −2} yr{sup −1}. The average NPP exhibited a fluctuation but presented a generally increasing trend over the 31-year study period, with an increase rate of 1.31 g cm{sup −2} yr{sup −2}. During the entire study period, the average contributions of temperature, precipitation, and solar radiation to NPP interannual variation over the entire region were 0.58, 0.73, and 0.09 g cm{sup −2} yr{sup −2}, respectively. Radiation was the climate factor with the greatest influence on NPP interannual variation. The factor that restricted NPP increase changed from temperature and radiation to precipitation. The average contributions of climate change and human activities to NPP interannual variation were 1.40 g cm{sup −2} yr{sup −2} and − 0.08 g cm{sup −2} yr{sup −2}, respectively. From 1982 to 2000, the general climate conditions were favorable to vegetation recovery, whereas human activities had a weaker negative impact on vegetation growth. From 2001 to 2012, climate conditions began to have a negative impact on vegetation growth, whereas human activities made a favorable impact on vegetation

  12. Vegetation dynamics in response to water inflow rates and fire in a brackish Typha domingensis Pers. marsh in the delta of the Colorado River, Mexico

    Science.gov (United States)

    Mexicano, Lourdes; Nagler, Pamela L.; Zamora-Arroyo, Francisco; Glenn, Edward P.

    2012-01-01

    The Cienega de Santa Clara is a 5600 ha, anthropogenic wetland in the delta of the Colorado River in Mexico. It is the inadvertent creation of the disposal of brackish agricultural waste water from the U.S. into the intertidal zone of the river delta in Mexico, but has become an internationally important wetland for resident and migratory water birds. We used high resolution Quickbird and WorldView-2 images to produce seasonal vegetation maps of the Cienega before, during and after a test run of the Yuma Desalting Plant, which will remove water from the inflow stream and replace it with brine. We also used moderate resolution, 16-day composite NDVI imagery from the Moderate Resolution Imaging Spectrometer (MODIS) sensors on the Terra satellite to determine the main factors controlling green vegetation density over the years 2000–2011. The marsh is dominated by Typha domingensis Pers. with Phragmites australis (Cav.) Trin. Ex Steud. as a sub-dominant species in shallower marsh areas. The most important factor controlling vegetation density was fire. Spring fires in 2006 and 2011 were followed by much more rapid green-up of T. domingensis in late spring and 30% higher peak summer NDVI values compared to non-fire years (P < 0.001). Fires removed thatch and returned nutrients to the water, resulting in more vigorous vegetation growth compared to non-fire years. The second significant (P < 0.01) factor controlling NDVI was flow rate of agricultural drain water from the U.S. into the marsh. Reduced summer flows in 2001 due to canal repairs, and in 2010 during the YDP test run, produced the two lowest NDVI values of the time series from 2000 to 2011 (P < 0.05). Salinity is a further determinant of vegetation dynamics as determined by greenhouse experiments, but was nearly constant over the period 2000–2011, so it was not a significant variable in regression analyses. It is concluded that any reduction in inflow volumes will result in a linear decrease in green foliage

  13. Hydrologic, vegetation, and soil data collected in selected wetlands of the Big River Management area, Rhode Island, from 2008 through 2010

    Science.gov (United States)

    Borenstein, Meredith S.; Golet, Francis C.; Armstrong, David S.; Breault, Robert F.; McCobb, Timothy D.; Weiskel, Peter K.

    2012-01-01

    The Rhode Island Water Resources Board planned to develop public water-supply wells in the Big River Management Area in Kent County, Rhode Island. Research in the United States and abroad indicates that groundwater withdrawal has the potential to affect wetland hydrology and related processes. In May 2008, the Rhode Island Water Resources Board, the U.S. Geological Survey, and the University of Rhode Island formed a partnership to establish baseline conditions at selected Big River wetland study sites and to develop an approach for monitoring potential impacts once pumping begins. In 2008 and 2009, baseline data were collected on the hydrology, vegetation, and soil characteristics at five forested wetland study sites in the Big River Management Area. Four of the sites were located in areas of potential drawdown associated with the projected withdrawals. The fifth site was located outside the area of projected drawdown and served as a control site. The data collected during this study are presented in this report.

  14. A Study of Vegetation Development in Relation to Age of River Stabilization Structures Along a Channelized Segment of the Missouri River.

    Science.gov (United States)

    1975-01-25

    Featherly (1941) both concluded that riparian woodlands develop into Quercus macrocarpa (bur oak) - Quercus borealis (red oak) - Carya illinoensis (pecan...dominated communit4 es .. ........ .. 47 Quercus- Carya -dominated communities .. ........ .. 49 Diversity ......... ....................... .. 59 Similarity...Tilia-Quercus-dominated, and Quercus- Carya -dominated vegetation. The construction dates of the stabilization structures adjacent to the sites studied

  15. Agricultural non-point nitrogen pollution control function of different vegetation types in riparian wetlands: a case study in the Yellow River wetland in China.

    Science.gov (United States)

    Zhao, Tongqian; Xu, Huashan; He, Yuxiao; Tai, Chao; Meng, Hongqi; Zeng, Fanfu; Xing, Menglin

    2009-01-01

    Riparian wetland is the major transition zone of matter, energy and information transfer between aquatic and terrestrial ecosystems and has important functions of water purification and non-point pollution control. Using the field experiment method and an isotope tracing technique, the agricultural non-point nitrogen pollution control function of different vegetation types in riparian wetland was studied in the Kouma Section of the Yellow River. The results showed that the retention of agricultural non-point nitrogen pollution by riparian wetland soil occurs mainly in top 0-10 cm layer. The amount of nitrogen retained by surface soils associated with three types of vegetation are 0.045 mg/g for Phragmites communis Trin Linn, 0.036 mg/g for Scirpus triqueter Linn, and 0.032 mg/g for Typha angustifolia Linn, which account for 59.21%, 56.25%, and 56.14% of the total nitrogen interception, respectively. Exogenous nitrogen in 0-10 cm soil layer changes more quickly than in other layers. One month after adding K(15)NO3 to the tested vegetation, nitrogen content was 77.78% for P. communis Trin, 68.75% for T. angustifolia, and 8.33% for S. triqueter in the surface soil. After three months, nitrogen content was 93.33% for P. communis Trin, 72.22% for S. triqueter, and 37.50% for T. Angustifolia. There are large differences among vegetation communities respecting to purification of agricultural non-point nitrogen pollution. The nitrogen uptake amount decreases in the sequence: new shoots of P. communis Trin (9.731 mg/g) > old P. communis Trin (4.939 mg/g) > S. triqueter (0.620 mg/g) > T. angustifolia (0.186 mg/g). Observations indicated that the presence of riparian wetlands as buffers on and adjacent to stream banks could be recommended to control agricultural non-point pollution.

  16. Agricultural non-point nitrogen pollution control function of different vegetation types in riparian wetlands: A case study in the Yellow River wetland in China

    Institute of Scientific and Technical Information of China (English)

    ZHAO Tongqian; XU Huashan; HE Yuxiao; TAI Chao; MENG Hongqi; ZENG Fanfu; XING Menglin

    2009-01-01

    Riparian wetland is the major transition zone of matter, energy and information transfer between aquatic and terrestrial ecosystems and has important functions of water purification and non-point pollution control. Using the field experiment method and an isotope tracing technique, the agricultural non-point nitrogen pollution control function of different vegetation types in riparian wetland was studied in the Kouma Section of the Yellow River. The results showed that the retention of agricultural non-point nitrogen pollution by riparian wetland soil occurs mainly in top 0-10 cm layer. The amount of nitrogen retained by surface soils associated with three types of vegetation are 0.045 mg/g for Phragmites communis Trin Lima, 0.036 mg/g for Scirpus triqueter Liun, and 0.032 mg/g for Typha angustifolia Linn, which account for 59.21%, 56.25%, and 56.14% of the total nitrogen interception, respectively. Exogenous nitrogen in 0-10 cm soil layer changes more quickly than in other layers. One month after adding K15NO3 to the tested vegetation, nitrogen content was 77.78% for P. Communis Trin, 68.75% for T. Angustifolia, and 8.33% for S. Triqueter in the surface soil. After three months, nitrogen content was 93.33% for P. Communis Trin, 72.22% for S. Triqueter, and 37.50% for T. Angustifolia. There are large differences among vegetation communities respecting to purification of agricultural non-point nitrogen pollution. The nitrogen uptake amount decreases in the sequence: new shoots of P. Communis Trin (9.731 mg/g)>old P. Communis Trin (4.939 mg/g)>S. Triqueter (0.620 mg/g)>T. Angustifolia (0.186 mg/g). Observations indicated that the presence of riparian wetlands as buffers on and adjacent to stream banks could be recommended to control agricultural non-point pollution.

  17. Wind tunnel experiments of air flow patterns over nabkhas modeled after those from the Hotan River basin,Xinjiang,China(Ⅰ):non-vegetated

    Institute of Scientific and Technical Information of China (English)

    Zhizhong LI; Wanjuan LI; Shengli WU; Janis DALE; Lin GE; Mudan HE; Xiaofeng WANG; Jianhui JIN; Rong MA; Jinwei LIU

    2008-01-01

    A nabkha is a vegetated sand mound,which is ypical of the aeolian landforms found in the Hotan River pasin in Xinjiang,China.This paper compares the results of a series of wind tunnel experiments with an on-site field survey of nabkhas in the Hotan River basin of Xinjiang.Wind tunnel experiments were conducted on semi-sphercal and conical sand mounds without vegetation or shadow dunes.Field mounds were 40 times as large as the size of the wind tunnel models.In the wind tunnel experiments,five different velocities from 6 to 14 m/s were selected and used to model the wind flow pattern over mdividual sand mound using clean air without additional sand.Changes in the flow pattern at different wind speeds resulted in changes to the characteristic structure of the babkha surface.The results of the experiments for the semi-spherical sand mound at all wind velocities show the formation of a vortex at the bottom of the upwind side of the mound that resulted in scouring and deposition of a crescentic dune upwind of the main mound.The top part of the sand mound is strongly eroded.In the field,these dunes exhibited the same scouring and crescentic dune formation and the eroded upper surface was often topped by a layer of peat within the mound suggesting destroyed vegetation due to river channel migration or by possible anthropogenic forces such as fuel gathering,etc.Experiments for the conical mounds exhibit only a small increase in velocity on the upwind side of the mound and no formation of a vortex at the bottom of the upwind side.Instead,a vortex formed on the leeward side of the mound and overall,no change occurred in the shape of the conical mound.In the field,conical mounds have no crescentic dunes on the upwind side and no erosion at the top exposed below peat beds.Therefore,the field and laboratory experiments show that semi-spherical and conical sand mounds respond differently to similar wind conditions with different surface configuration and development of crescent

  18. Vegetation habitat units derived from 2011 aerial imagery and field data for the Elwha River estuary, Washington

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Estuary vegetation cover delineated from 3 September 2011 0.3-meter-resolution aerial imagery (Microsoft/Digital Globe) at a scale of 1:1500. Image date of 3-Sep...

  19. Hysteresis effect of runoff of the Heihe River on vegetation cover in the Ejina Oasis in Northwestern China

    NARCIS (Netherlands)

    Jin, X.; Hu, G.C.; Li, W.M.

    2008-01-01

    The relationship between vegetation growth and groundwater in arid areas is one of the most actively researching topics in ecohydrology. On account of little precipitation, the oasis is the only form of sustenance for living and economic development, for the local people in the arid areas of Northwe

  20. Projecting avian response to linked changes in groundwater and riparian floodplain vegetation along a dryland river: a scenario analysis

    Science.gov (United States)

    Groundwater is a key driver of riparian condition on dryland rivers but is in high demand for municipal, industrial, and agricultural uses. Approaches are needed to guide decisions that balance human water needs while conserving riparian ecosystems. We developed a space-for-time substitution model ...

  1. Long-term vegetation landscape pattern with non-point source nutrient pollution in upper stream of Yellow River basin

    NARCIS (Netherlands)

    Ouyang, W.; Skidmore, A.K.; Toxopeus, A.G.; Hao, F.

    2010-01-01

    Grassland, forest, and farmland are the dominant land covers in upper catchments of the Yellow River and their landscape status has direct connection with dynamics of non-point source (NPS) pollution. Understanding the correlations between landscape variables and different formats of NPS nutrients p

  2. Phenological response of vegetation to upstream river flow in the Heihe Rive basin by time series analysis of MODIS data

    NARCIS (Netherlands)

    Jia, L.; Shang, H.L.; Hu, G.; Menenti, M.

    2011-01-01

    Liquid and solid precipitation is abundant in the high elevation, upper reach of the Heihe River basin in northwestern China. The development of modern irrigation schemes in the middle reach of the basin is taking up an increasing share of fresh water resources, endangering the oasis and traditional

  3. Long-term vegetation landscape pattern with non-point source nutrient pollution in upper stream of Yellow River basin

    NARCIS (Netherlands)

    Ouyang, W.; Skidmore, A.K.; Toxopeus, A.G.; Hao, F.

    2010-01-01

    Grassland, forest, and farmland are the dominant land covers in upper catchments of the Yellow River and their landscape status has direct connection with dynamics of non-point source (NPS) pollution. Understanding the correlations between landscape variables and different formats of NPS nutrients p

  4. Soil erosion and sediment yield and their relationships with vegetation cover in upper stream of the Yellow River

    NARCIS (Netherlands)

    Ouyang, W.; Hao, F.; Skidmore, A.K.; Toxopeus, A.G.

    2010-01-01

    Soil erosion is a significant concern when considering regional environmental protection, especially in the Yellow River Basin in China. This study evaluated the temporal-spatial interaction of land cover status with soil erosion characteristics in the Longliu Catchment of China, using the Soil and

  5. Changes in Vegetation Coverage of the Inland River Banks in Different Periods Based on Remote Sensing%不同时期内陆河两岸地表植被覆盖度变化研究

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    石羊河流域是典型的内陆河流域系统,20世纪70年代因修建水库致使下游河道断流,河岸两侧植被盖度因地下水位下降及河道渗漏补给减少而缓慢发生变化。通过遥感监测手段,对不同时期影像所反映的植被信息进行提取,分析了河道两侧5 km范围的植被盖度变化信息,结果表明:以河道侧渗为主要补给的区域,80%的植被盖度为中高盖度,而中盖度植被变化强烈;有水的上游河段植被变异小,断流的下游植被变异大,低盖度植被地类增加明显。研究揭示了干旱荒漠区内陆河流域修建水库会导致下游断流区域河岸植被盖度的显著变化。%Shiyang River Basin is a typical inland river basin system .In the seventies of the last century ,the construction of reser‐voirs led to the the drying up of downstream rivers ,the drop of underground water level and decreased river seepage ,so the vegeta‐tion coverage on both sides of the bank changed slowly .Through the remote sensing monitoring means ,vegetation information from different periods images were extracted and vegetation cover change information of both sides of the river 5km range was analyzed . Its results show that :lateral seepage of the river was as the main recharge area ,80% the vegetation cover was the high coverage , while the changes of middle level vegetation cover was strong .The little variation of vegetation occurred in the upper reaches ,and the cutting off downstream had large variation ,and low vegetation coverage increased significantly .The research results revealed that the construction of reservoirs in arid desert inland river basin could lead to significant changes in riparian vegetation cover in the downstream cutoff region .

  6. Attribution of satellite observed vegetation trends in a hyper-arid region of the Heihe River Basin, Central Asia

    Directory of Open Access Journals (Sweden)

    Y. Wang

    2014-02-01

    4.5% in 2012. The largest contribution to the overall greening was due to changes in green vegetation cover of the extensive desert areas with a smaller contribution due to changes in the area of irrigated land. Comprehensive analysis with different precipitation data sources found that the greening of the desert was associated with increases in regional precipitation. We found that the area of land irrigated each year was mostly dependent on the runoff gauged one year earlier. Taken together, water availability both from precipitation in the desert and runoff inflow for the irrigation agricultural lands can explain at least 52% of the total variance in regional vegetation cover from 2000 to 2010.

  7. Diametric structure of the shrub and tree vegetation around the headwaters in the Piauitinga River drainage basin, Salgado – Sergipe, Brazil

    Directory of Open Access Journals (Sweden)

    Ednei Santos de Almeida

    2013-06-01

    Full Text Available This study was carried out in order to analyze the diametric structure of the ciliary vegetation in headwaters in the Piauitinga River drainage basin, located at the town of Salgado, Sergipe, Brazil. One analyzed 14 headwaters, using a classification with regard to the conservation status and the type of reservoir, being divided into 4 categories: 1 punctual preserved (PPr, 1 punctual disturbed (PD, 6 punctual degraded (PD, and 6 diffuse degraded (DD. The survey was conducted through a population census of vegetation in a 50 m radius around the headwaters, equivalent to 0.79 ha, where one recorded all living shrub and tree individuals with diameter at breast height (DBH ≥ 5.0 cm. The individuals were distributed into diametric classes, at 2.5 cm intervals. The punctual preserved and the punctual disturbed headwaters showed a diametric structure characteristic of heterogeneous forests, with an “inverted J” shape. The diffuse and punctual degraded headwaters didn’t show the “inverted J” pattern, except for DD2, perhaps reflecting the higher numberof individuals in this headwater. The intense disturbance generated in the headwater areas, which are currently degraded, promoted the impoverishment of natural regeneration and, as a result, compromised the recruitment of individuals in the early diameter grades.

  8. Impacts of Climate Change and Vegetation Dynamics on Runoff in the Mountainous Region of the Haihe River Basin in the Past Five Decades

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Huimin; Yang, Dawen; Huang, Maoyi

    2014-04-16

    Climate and atmospheric CO2 concentration have changed significantly in the mountainous region of the Haihe River basin over the past five decades. In the study, a process-based terrestrial model, version 4 of the Community Land Model (CLM4), was used to quantify the spatiotemporal changes in runoff over the region, driven by the varying climate factors and CO2 concentration. Overall, our simulations suggest that climate-induced change in runoff in this region show a decreasing trend since 1960. Changes in precipitation, solar radiation, air temperature, and wind speed accounts for 56%, -14%, 13%, -5% of the overall decrease in annual runoff, respectively, but their relative contributions vary across the study area. Rising atmospheric CO2 concentration was found to have limited impacts on runoff. Significant decrease in runoff over the southern and northeastern portion of the region is primarily attributed to decreasing precipitation, while decreasing solar radiation and increasing air temperature are the main causes of slight runoff increase in the northern portion. Our results also suggest that the magnitude of decreasing trend could be greatly underestimated if the dynamical interactions of vegetation phenology with the environmental factors are not considered in the modeling, highlighting the importance of including dynamic vegetation phenology in the prediction of runoff in this region.

  9. Holocene Vegetation Succession and Response to Climate Change on the South Bank of the Heilongjiang-Amur River, Mohe County, Northeast China

    Directory of Open Access Journals (Sweden)

    Chao Zhao

    2016-01-01

    Full Text Available Pollen samples from peat sediments on the south bank of the Heilongjiang River in northern Northeast China (NE China were analyzed to reconstruct the historical response of vegetation to climate change since 7800 cal yr BP. Vegetation was found to have experienced five successions from cold-temperate mixed coniferous and broadleaved forest to forest-steppe, steppe-woodland, steppe, and finally meadow-woodland. From 7800 to 7300 cal yr BP, the study area was warmer than present, and Betula, Larix, and Picea-dominated mixed coniferous and broadleaved forests thrived. Two cooling events at 7300 cal yr BP and 4500 cal yr BP led to a decrease in Betula and other broadleaved forests, whereas herbs of Poaceae expanded, leading to forest-steppe and then steppe-woodland environments. After 2500 cal yr BP, reduced temperatures and a decrease in evaporation rates are likely to have resulted in permafrost expansion and surface ponding, with meadow and isolated coniferous forests developing a resistance to the cold-wet environment. The Holocene warm period in NE China (7800–7300 cal yr BP could have resulted in a strengthening of precipitation in northernmost NE China and encouraged the development of broadleaved forests.

  10. Biogenic VOCs emission inventory development of temperate grassland vegetation in Xilin River Basin,Inner Mongolia,China

    Institute of Scientific and Technical Information of China (English)

    HE Nian-peng; HAN Xing-guo; SUN Wei; Pan Qing-min

    2004-01-01

    Given the key role of biogenic volatile organic compounds(VOCs) to tropospheric chemistry and regional air quality, it is important to generate accurate VOCs emission inventories. However, only a less fraction of plant species, in temperate grassland of Inner Mongolia, has been characterized by quantitative measurements. A taxonomic methodology, which assigns VOCs measurements to unmeasured species, is an applicable and inexpensive alternation for extensive VOCs emission survey, although data are needed for additional plant families and genera to further validate the taxonomic approach in grassland vegetation. In this experiment, VOCs emission rates of 178 plant species were measured with a portable photoionization detector(PID). The results showed the most of genera and some families have consistent feature of their VOCs emission, especially for isoprene, and provide the basic premise of taxonomic methodology to develop VOCs emission inventories for temperate grassland. Then, the taxonomic methodology was introduced into assigning emission rate to other 96 species, which no measured emission rates available here. A systematical emission inventory of temperate grassland vegetation in Inner Mongolia was provided and further evidence that taxonomy relationship can serve as a useful guide for generalizing the emissions behavior of many, but not all, plant families and genera to grassland vegetation.

  11. General Classification Handbook for Floodplain Vegetation in Large River Systems. Chapter 1 of Book 2, Collection of Environmental Data

    Science.gov (United States)

    2004-01-01

    tuberculatus WM Amorpha A. fruiticosa WMS Betula B. nigra FF, LF Bidens B. cernua, B. frondosa SMA Carex C. spp.1 SM Carya C. cordiformis, C. illinoensis LF...include pecan ( Carya ), hickory ( Carya ), river birch (Betula), sycamore (Platanus), and red/black oak (Quercus). This general class is most com- mon...near the edge of the floodplain, or out of the floodplain. This general class typi- cally consists of red or white oak (Quercus), hickory ( Carya

  12. Vegetation and proximity to the river control amorphous silica storage in a riparian wetland (Biebrza National Park, Poland

    Directory of Open Access Journals (Sweden)

    E. Struyf

    2009-01-01

    Full Text Available Wetlands can modify and control nutrient fluxes between terrestrial and aquatic ecosystems, yet little is known of their potential as biological buffers and sinks in the biogeochemical silica cycle. We investigated the storage of amorphous silica (ASi in a central-European riparian wetland. The variation in storage of ASi in the soil of an undisturbed wetland was significantly controlled by two factors: dominance of sedges and grasses and distance to the river (combined R2=78%. Highest ASi storage was found near the river and in sites with a dominance of grasses and sedges, plants which are well known to accumulate ASi. The management practice of mowing reduced the amount of variation attributed to both factors (R2=51%. Although ASi concentrations in soils were low (between 0.1 and 1% of soil dry weight, ASi controlled the availability of dissolved silica (DSi in the porewater, and thus potentially the exchange of DSi with the nearby river system through both diffusive and advective fluxes. A depth gradient in ASi concentrations, with lower ASi in the deeper layers, indicates dissolution. Our results show that storage and recycling of ASi in wetland ecosystems can differ significantly on small spatial scales. Human management interferes with the natural control mechanisms. Our study demonstrates that wetlands have the potential to modify the fluxes of both DSi and ASi along the land-ocean continuum and supports the hypothesis that wetlands are important ecosystems in the biogeochemical cycling of silica.

  13. Summer nitrate uptake and denitrification in an upper Mississippi River backwater lake: The role of rooted aquatic vegetation

    Science.gov (United States)

    Kreiling, Rebecca M.; Richardson, W.B.; Cavanaugh, J.C.; Bartsch, L.A.

    2011-01-01

    In-stream nitrogen processing in the Mississippi River has been suggested as one mechanism to reduce coastal eutrophication in the Gulf of Mexico. Aquatic macrophytes in river channels and flood plain lakes have the potential to temporarily remove large quantities of nitrogen through assimilation both by themselves and by the attached epiphyton. In addition, rooted macrophytes act as oxygen pumps, creating aerobic microsites around their roots where coupled nitrification-denitrification can occur. We used in situ 15N-NO3- tracer mesocosm experiments to measure nitrate assimilation rates for macrophytes, epiphyton, and microbial fauna in the sediment in Third Lake, a backwater lake of the upper Mississippi River during June and July 2005. We measured assimilation over a range of nitrate concentrations and estimated a nitrate mass balance for Third Lake. Macrophytes assimilated the most nitrate (29.5 mg N m-2 d-1) followed by sediment microbes (14.4 mg N m-2 d-1) and epiphytes (5.7 mg N m-2d-1. Assimilation accounted for 6.8% in June and 18.6% in July of total nitrate loss in the control chambers. However, denitrification (292.4 mg N m-2 d-1) is estimated to account for the majority (82%) of the nitrate loss. Assimilation and denitrification rates generally increased with increasing nitrate concentration but denitrification rates plateaued at about 5 mg N L-1. This suggests that backwaters have the potential to remove a relatively high amount of nitrate but will likely become saturated if the load becomes too large. ?? 2010 US Government.

  14. Long-term change in perennial vegetation along the Colorado river in Grand Canyon national park (1889-2010)

    Science.gov (United States)

    Webb, R.H.; Belnap, J.; Scott, M.L.; Esque, T.C.

    2011-01-01

    Long-term monitoring data are difficult to obtain for high-value resource areas, particularly in remote parts of national parks. One long-used method for evaluating change uses ground-based repeat photography to match historical images of landscapes. River expeditions that documented a proposed railroad route through Grand Canyon with large-format photographs occurred in 1889 and 1890. A total of 452 images from those expeditions are still in existence, and these were matched as closely as possible from December 1989 through March 1992. In 2010 and 2011, we are repeating these matches 120 years after the originals and 20 years after the first matches. This repeat photography provides visual information that can be interpreted for changes in terrestrial and riparian ecosystems along the river corridor, including change in the desert plant assemblages related to increasing winter low temperatures and severe drought. The riparian ecosystem, which originally consisted of native species established along the stage of frequent floods, has increased in area, density, and biomass as both nonnative and native species have become established following flow regulation by Glen Canyon Dam. The original and matched images provide the basis for one element of a robust monitoring program for the effects of climate change on ecosystem resources.

  15. Vegetation heterogeneity on a Late Pennsylvanian braided-river plain draining the Variscan Mountains, La Magdalena Coalfield, northwestern Spain

    DEFF Research Database (Denmark)

    Bashforth, Arden Roy; Falcon-Lang, Howard J; Gibling, Martin R

    2010-01-01

    The spatial heterogeneity and community ecology is reconstructed for Late Pennsylvanian (Stephanian B sensu lato) vegetation preserved in La Magdalena Coal¿eld, northwestern Spain. The ˜ 1500 m thick basin- ¿ll accumulated rapidly along the margin of the Variscan Mountains, and the principal...... pteridium, and Neuropteris ovata) accounting for ˜58% of all plant remains. Sphenopsids and lycopsids were less common but widespread, and cordaitaleans were rare. At the local scale, laterally exposed bedding planes reveal that communities comprised a complex and heterogeneous mosaic of species....... At the landscape scale, ecological gradients are evident from multivariate analyses of quadrats in a facies context. Pteridosperms dominated marginal wetlands adjacent to steep basin margins. A greater proportion of ferns occurred in or adjacent to braided channel belts, consistent with their opportunistic growth...

  16. River

    Directory of Open Access Journals (Sweden)

    Morel Mathieu

    2016-01-01

    Full Text Available The OECD report “Boosting Resilience through Innovative Risk Governance” examines the efforts of OECD countries to prevent or reduce future disaster impacts, and highlights several key areas where improvements can be made. International collaboration is insufficiently utilised to address shocks that have increasingly global consequences. Institutional design plays a significant role in facilitating or hampering the engagement and investments of governmental and non-governmental stakeholders in disaster risk prevention and mitigation. To inform the design of “better” institutions, the OECD proposes the application of a diagnostic framework that helps governments identify institutional shortcomings and take actions to improve them. The goal of the case study on the Rhone River is to conduct an analysis of the progress, achievements and existing challenges in designing and implementing disaster risk reduction strategies through the Rhone Plan from a comparative perspective across a set of selected countries of this study, like Austria and Switzerland, will inform how to improve institutional frameworks governing risk prevention and mitigation. The case study will be used to identify examples of successful practice taking into account their specific country contexts, and analyse their potential for policy transfer.

  17. Response of Vegetation Dynamics to Projected Climate Change based on NDVI Simulations using Stepwise Cluster Analysis in the Three-River Headwaters Region of China

    Science.gov (United States)

    Zheng, Y.; Lv, E.; Huang, Y.

    2016-12-01

    Located in the hinterland of the Qinghai-Tibetan Plateau, the Three-River Headwaters region (THR) features unique eco-environmental conditions and fragile ecosystems, and is very vulnerable to climate change. To investigate the effects of climate change on the ecosystem, the Normalized Difference Vegetation Index (NDVI) was employed as an indicator to reflect the vegetation dynamics in response to climate change. This study proposed a model based on Stepwise-cluster analysis to predict the temporal and spatial distributions of NDVI values for five future years according to Global Circulation Models (GCMs) climate projections under the RCP4.5 scenario. The obtained spatial results showed very good agreements between simulations and remote sensing observations of the NDVI value for both training and validation, and the developed model demonstrated its capability of predicting the monthly changes of NDVI through representing the relationships between it and various climatic factors, including remote sensed precipitation and temperature with no, 1 and 2-month lag period. The monthly average precipitation with one-month lag period was further found to be the most important climatic factor that drives the changes of NDVI in the THR. Compared with the values of NDVI in 2000 - 2013, the predicting results indicate the values of NDVI for the THR in growing season (May to October) will decrease by 15.74% in the next 100 years, suggesting that the THR is going to experience an environmental degradation. The results also show that precipitation is the primary driving factor relative to temperature, especially the one-month-lag precipitation. Findings from this study would help policy makers draw up effective water resource and eco-environmental management strategies for adapting to climate change in the THR.

  18. Vegetation Control in the Long-term Self-stabilisation of the Liangzhou Oasis of the Upper Shiyang River Watershed of West-central Gansu, NW China

    Science.gov (United States)

    Bourque, Charles; Hassan, Quazi

    2010-05-01

    Oases are special ecological systems that naturally oppose the encroachment of deserts by staying moist. Oases provide important habitat refugia for plants, animals, and humans alike. Oases in NW China account for only about 5% of the total land area of the region, but give shelter and feed about 95% of the area's growing population. It has been proposed by many scientists and observers of desertification in NW China that rapid economic development in the area is largely unsustainable and is occurring at the very detriment of the oases. This presentation explores the relationship between vegetation in the Liangzhou Oasis in the Upper Shiyang River Watershed (USRW) of west-central Gansu, China, and within-watershed precipitation, soil water storage, and oasis self-support. Oases along the base of the Qilian Mountains receive a significant portion of their water supply (> 90%) from surface and subsurface flow originating from the Qilian Mountains. Investigation of vegetation control on oasis-water conditions in the USRW is based on an application of a process model of soil-water hydrology. The model is used to simulate long-term soil water content in the Liangzhou Oasis as a function of (i) monthly composites of MODIS images of land surface and mean air temperature, (ii) spatiotemporal calculations of monthly precipitation and relative humidity generated with the assistance of genetic algorithms, and (iii) an 80-m resolution digital elevation model of the area. Modelled removal of vegetation is shown to affect within-watershed precipitation and soil water storage by reducing the exchange of water vapour from the land surface to the air, increasing the air's lifting condensation level by promoting drier air conditions, and causing the high-intensity precipitation band in the Qilian Mountains to weaken and to be displaced upward in the watershed, leading to an overall reduction in soil water in the Liangzhou Oasis. Feedback mechanisms of oasis self-support introduced

  19. 漓江流域近15年遥感植被覆盖度fveg变化特征%Vegetation coverage changes in the Lijiang river basin based on remote sensing in recent 15 years

    Institute of Scientific and Technical Information of China (English)

    靖娟利; 王永锋

    2014-01-01

    为研究漓江流域近15年植被覆盖度变化情况,以1991、2000、2006年3个时相的TM/ETM+影像为基础,采用基于归一化植被指数(NDVI)的像元二分模型对漓江流域植被覆盖度进行估算,分析了植被覆盖度时空变化特征;结合研究区地质数据,进一步分析地质条件对植被覆盖度的影响。结果表明:①受气候和人类活动的影响,1991-2000年漓江流域植被覆盖度有所增加,表现为高和较高植被覆盖区面积增加,中度、较低和低植被覆盖区面积减少;2000-2006年漓江流域植被覆盖度略有降低,表现为高植被覆盖区面积减少,较高和中度植被覆盖区增加,较低和低植被覆盖区面积减少;②由于地质条件的影响,非岩溶区的平均植被覆盖度高于岩溶区,两者的变化趋势与流域整体变化基本一致;③从空间分布上看,1991-2006年漓江流域植被覆盖度的变化较显著。%In order to study the vegetation coverage changes of the Lijiang river basin in 15 years,with Landsat TM/ETM+data of 1991,2000 and 2006 as data sources,by dimidiate pixel model based on NDVI,the vege-tation coverage of the Lijiang river basin is evaluated and characteristics of temporal-spatial changes are analyzed in past 15 years.From the geological data in the study area,influences of the geological conditions to vegeta-tion coverage are analyzed.Results are described in three aspects:①Because of the climate and human activi-ties,the vegetation coverage in the Lijiang river basin got a rise in 1991 -2000.The area of high and higher vegetation coverage districts increased,while that of middle,low and lower vegetation coverage districts de-creased.Vegetation coverage got a decrease in 2000-2006.The area of high vegetation coverage districts de-creased,higher and middle vegetation coverage districts increased,while that low and lower vegetation cover-age districts decreased;②Due to the influence

  20. Heavy metal pollution of soils and vegetables in the midstream and downstream of the Xiangjiang River, Hunan Province%湘江中下游农田土壤和蔬菜的重金属污染

    Institute of Scientific and Technical Information of China (English)

    王莉霞; 郭朝晖; 肖细元; 陈同斌; 廖晓勇; 宋杰; 武斌

    2008-01-01

    A total of 219 agricultural soil and 48 vegetable samples were collected from the midstream and downstream of the Xiangjiang River (the Hengyang-Changsha section) in Hunan Province. The accumulation characteristics, spatial distribution and potential risk of heavy metals in the agricultural soils and vegetables were depicted. There are higher accu- mulations of heavy metals such as As, Cd, Cu, Ni, Pb and Zn in agricultural soils, and the contents of Cd (2.44 mg kg-1), Pb (65.00 mg kg-1) and Zn (144.13 mg kg-1) are 7.97, 3.69 and 1.63 times the corresponding background contents in soils of Hunan Province, respectively. 13.2% of As, 68.5% of Cd, 2.7% of Cu, 2.7% of Ni, 8.7% of Pb and 15.1% of Zn in soil sam- ples from the investigated sites exceeded the maximum allowable heavy metal contents inthe China Environmental Quality Standard for Soils (GB15618-1995, Grade II). The pollution characteristics of multi-metals in soils are mainly due to Cd. The contents of As, Cd, Cu, Pb and Zn in vegetable soils are significantly higher than the contents in paddy soils. 95.8%, 68.8%, 10.4% and 95.8% of vegetable samples exceeded the Maximum Levels of Contami- nants in Foods (GB2762-2005) for As, Cd, Ni and Pb concentrations, respectively. There are significantly positive correlations between the concentrations of Cd, Pb and Zn in vegetables and the concentrations in the corresponding vegetable soils (p<0.01). It is very necessary to focus on the potential risk of heavy metals for food safety and human health in agricultural soils and vegetables in the midstream and downstream of the Xiangjiang River, Hunan Province of China.

  1. CHANGES IN THE MOISTURE CONTENT OF THE MIDDLE FEN SOILS IN THE ODRA RIVER VALLEY IN THE REGION OF BRZEG DOLNY IN THE VEGETATION PERIODS 2004–2009

    Directory of Open Access Journals (Sweden)

    Leszek Pływaczyk

    2014-10-01

    Full Text Available In soils, where the water table is deeply located and has a minor impact on the moisture content of the surface layer, we are dealing with the precipitation-and-water type of water management. If underground water level is close to the surface, the top stratum of the soil, apart from precipitation, is additionally fed by water absorption from underground waters. Then we are dealing with ground-and-water type of management. We consider such types of water management of soil in the area of the left-bank valley of the Odra river, above and below the dam in Brzeg Dolny. The dominant soil types here are middle fen soils, based on middle clay and heavy clay as well as loam, which, in conditions of either excess or deficiency of moisture, are difficult to cultivate. The work compares water management of two soil profiles in vegetation periods between 2004 and 2009. The formation of underground waters, meteorological conditions and the course of the water reserves in the strata 0–50 cm and 0–100 cm were estimated with various supplying conditions of the active stratum of the soil. The volume of the supply with percolated water from underground water of the layer 50–100 cm on approximately 75–90 mm was also estimated. This value was mainly dependent on the depth of the retention of the water table of the soil profile above the level in Brzeg Dolny.

  2. Landscape gradients and patchiness in riparian vegetation on a Middle Pennsylvanian braided-river plain prone to flood disturbance (Nýrany Member, Central and Western Bohemian Basin, Czech Republic)

    DEFF Research Database (Denmark)

    Bashforth, Arden Roy; Drábková, Jana; Opluštil, Stanislav

    2011-01-01

    and conglomerate dominate at the four localities studied, but fine-grained intercalations, representing abandoned channels, floodplains, and shallow lakes, yielded rich megafloral and palynological assemblages. Sedimentological evidence indicates that high-energy flow characterized a braided-river plain prone......, and ephemeral mires on distal floodplains. The heterogeneous distribution of riparian plants is consistent with that of modern, disturbance-dominated fluvial environments, although Pennsylvanian species richness was much lower. A review of floristic patterns in latest Middle Pennsylvanian vegetation...

  3. Measuring sap flow, and other plant physiological conditions across a soil salinity gradient in the lower Colorado River at Cibola National Wildlife Refuge: Vegetation and soil physiology linkages with microwave dielectric constant

    Science.gov (United States)

    McDonald, K. C.; Lasne, Y.; Schroeder, R.; Morino, K.; Hultine, K. R.; Nagler, P. L.

    2009-12-01

    We used ground measurements to examine stand structure and evapotranspiration of Tamarix in the Cibola National Wildlife Refuge (CNWR) on the Lower Colorado River. Three Tamarix study sites were established at different distances from the Colorado River on a river terrace in the CNWR. The sites were chosen from aerial photographs to represent typical dense stands of Tamarix within the CNWR. The sites were representative of differing saline environments, with each having ground water with distinct salt concentration levels. Wells were established at the site to establish depth to water and the salinity concentration within the ground water. We monitored xylem sap flow within each of the three stands. In addition we measured leaf area index to characterize canopy structure. We compared ET, foliage density, depth to water, and salinity among the Tamarix sites to examine stand-level variability driven by the variations in salinity. We supplemented these collections with measurements to characterize soil and vegetation microwave dielectric properties and their relationship to physiologic parameters. The dielectric properties of a material describe the interaction of an electric field with the material. Previous field experiments have demonstrated that varying degrees of correlation exist between vegetation dielectric properties and tree canopy water status. Temporal variation of the dielectric constant of woody plant tissue may result from changes in water status (e.g., water content) and chemical composition, albeit to varying degrees of sensitivity. The varying amount of ground water salinity at CNWR offers a unique opportunity to examine the relationship between vegetation and soil dielectric constant as related to vegetation ecophysiology. A field portable vector network analyzer is used to measure the microwave dielectric spectrum of the soil and vegetation Combined with measurements of vegetation xylem sap flux and soil chemistry, these measurements allow

  4. How Saharan Dust Slows River Knickpoints: Coupling Vegetation Canopy, Soils and the Foundation of the Critical Zone

    Science.gov (United States)

    Brocard, G. Y.; Willenbring, J. K.; Harrison, E. J.; Scatena, F. N.

    2015-12-01

    Forest succession theory maintains that trees drape existing landscapes as passive niche optimizers, but in the Luquillo Mountains in Puerto Rico, the forest exerts a powerful control on erosion. The Luquillo Critical Zone observatory is set in the Luquillo Mountains, an isolated massif at the northeastern tip of Puerto Rico Island which receives up to five meters of rainfall annually. Most of the rainfall received in the mountains is conveyed as quick flow through soil macropores, inhibiting soil erosion by overland flow. Physical erosion is kept low, occurring in the form of infrequent shallow landslides, thus increasing the residence time of minerals in the near-surface environment. The extensive chemical alteration of minerals generates a thick saprolite covered by fine-grained soil. Over the quartz diorite bedrock that characterizes the southern side of the mountains, the weathering process generates saprolite tens of meters deep that is almost completely devoid of weatherable minerals. Soils forming over this saprolite are nutrient-poor, forcing the rainforest to retrieve its nutrients from atmospheric fluxes, such as Saharan dust and marine aerosols. These atmospheric inputs are thus indirectly essential for the forest to be able to maintain slow erosion rates over the mountains. At lower elevation, using cosmogenic nuclide-derived denudation rates, we identified a wave of incision which has been propagating upstream over the past 4 My in the form of very steep and slowly migrating knickpoints. Bedrock abrasion and plucking are infrequent along the knickpoint faces, because the bedrock is massive and because rivers are bedload-starved. This situation is due to the highly weathered upland soils and slow erosion rates and high weathering rate upstream, which acts to reduce bedload grain size and limits bedload fluxes to the knickpoint, respectively. The soils change radically where the wave of erosion has passed and has increased erosion rates. There, nutrient

  5. Temperature, vegetation and precipitation variability in the Nile River drainage during the past 27,000 years: Insights from molecular and isotopic proxies

    Science.gov (United States)

    Castañeda, Isla; Schouten, Stefan; Pätzold, Jürgen; Schefuß, Enno

    2013-04-01

    The paleoclimate history of the Eastern Mediterranean (EM) region is of much interest due to its long history of human occupation. To date, much of our knowledge of past climate in the EM region comes from marine sedimentary records. These indicate that since the Last Glacial Maximum, major and sometimes abrupt sea surface temperature (SST) fluctuations occurred in response to global climate events including the Younger Dryas (YD), the Bølling-Allerød, and Heinrich Event 1 (H1). In comparison, less is known regarding continental paleoclimate conditions in this region due to a scarcity of well-dated continuous climate archives, particularly from Saharan North Africa. Here, we present new reconstructions of continental precipitation (plant leaf wax δD), C3 vs. C4 vegetation (plant leaf wax δ13C) and soil temperature (MBT/CBT paleothermometer) in the Nile River catchment in conjunction with previously published U37k' and TEX86SST reconstructions from the EM Sea. Our multiproxy records indicate that relative to the present, the LGM was characterized by arid conditions with cooler SST and soil temperatures in the catchment. The H1 event stands out as a major excursion in nearly all proxies and is characterized by an abrupt decrease in SST and the most arid conditions of the past 27,000 years. The African Humid Period (AHP) of the early Holocene is the wettest interval of the entire record and is observed from ~10,000 to 5,500 cal BP, with maximum wet conditions noted at ~8,000 cal BP. Interestingly, a rather abrupt cooling is noted in the MBT/CBT record at ~5.5 cal kyr, coinciding with the end of the AHP off west Africa; however, the transition out of the AHP is more gradual in the δD record. Overall both the continental and marine climate records indicate millennial scale climate variability. Our records also shed light on shifting sources of organic matter in response to the sequential cessation and re-initiation of different tributaries to the main flow of the

  6. An indicator to map diffuse chemical river pollution considering buffer capacity of riparian vegetation--a pan-European case study on pesticides.

    Science.gov (United States)

    Weissteiner, Christof J; Pistocchi, Alberto; Marinov, Dimitar; Bouraoui, Fayçal; Sala, Serenella

    2014-06-15

    Vegetated riparian areas alongside streams are thought to be effective at intercepting and controlling chemical loads from diffuse agricultural sources entering water bodies. Based on a recently compiled European map of riparian zones and a simplified soil chemical balance model, we propose a new indicator at a continental scale. QuBES (Qualitative indicator of Buffered Emissions to Streams) allows a qualitative assessment of European rivers exposed to pesticide input. The indicator consists of normalised pesticide loads to streams computed through a simplified steady-state fate model that distinguishes various chemical groups according to physico-chemical behaviour (solubility and persistence). The retention of pollutants in the buffer zone is modelled according to buffer width and sorption properties. While the indicator may be applied for the study of a generic emission pattern and for a chemical of generic properties, we demonstrate it to the case of agricultural emissions of pesticides. Due to missing geo-spatial data of pesticide emissions, a total pesticide emission scenario is assumed. The QuBES indicator is easy to calculate and requires far less input data and parameterisation than typical chemical-specific models. At the same time, it allows mapping of (i) riparian buffer permeability, (ii) chemical runoff from soils, and (iii) the buffered load of chemicals to the stream network. When the purpose of modelling is limited to identifying chemical pollution patterns and understanding the relative importance of emissions and natural attenuation in soils and stream buffer strips, the indicator may be suggested as a screening level, cost-effective alternative to spatially distributed models of higher complexity.

  7. Emissions of NO and NH3 from a typical vegetable-land soil after the application of chemical N fertilizers in the Pearl River Delta.

    Directory of Open Access Journals (Sweden)

    Dejun Li

    Full Text Available Cropland soil is an important source of atmospheric nitric oxide (NO and ammonia (NH3. Chinese croplands are characterized by intensive management, but limited information is available with regard to NO emissions from croplands in China and NH3 emissions in south China. In this study, a mesocosm experiment was conducted to measure NO and NH3 emissions from a typical vegetable-land soil in the Pearl River Delta following the applications of 150 kg N ha(-1 as urea, ammonium nitrate (AN and ammonium bicarbonate (ABC, respectively. Over the sampling period after fertilization (72 days for NO and 39 days for NH3, mean NO fluxes (± standard error of three replicates in the control and urea, AN and ABC fertilized mesocosms were 10.9±0.9, 73.1±2.9, 63.9±1.8 and 66.0±4.0 ng N m(-2 s(-1, respectively; mean NH3 fluxes were 8.9±0.2, 493.6±4.4, 144.8±0.1 and 684.7±8.4 ng N m(-2 s(-1, respectively. The fertilizer-induced NO emission factors for urea, AN and ABC were 2.6±0.1%, 2.2±0.1% and 2.3±0.2%, respectively. The fertilizer-induced NH3 emission factors for the three fertilizers were 10.9±0.2%, 3.1±0.1% and 15.2±0.4%, respectively. From the perspective of air quality protection, it would be better to increase the proportion of AN application due to its lower emission factors for both NO and NH3.

  8. Rational groundwater table indicated by the eco-physiological parameters of the vegetation: A case study of ecological restoration in the lower reaches of the Tarim River

    Institute of Scientific and Technical Information of China (English)

    CHEN Yaning; WANG Qiang; LI Weihong; RUAN Xiao; CHEN Yapeng; ZHANG Lihua

    2006-01-01

    The eco-physiological response and adaptation of Populus euphratica Oliv and Tamarix ramosissima Ldb during water release period were investigated. Nine typical areas and forty-five transects were selected along the lower reaches of Tarim River. The groundwater table as well as plant performance and the contents of proline, soluble sugars,and plant endogenous hormone (ABA, CTK) in leaves were monitored and analyzed. The groundwater table was raised in different areas and transects by water release program. The physiological stress to P. euphratica and T. ramosissima had been reduced after water release. Our results suggested that the groundwater table in the studied region remained at-3.15 to -4.12 m, the proline content from 9.28 to 11.06 (mmol/L), the soluble sugar content from 224.71 to 252.16 (mmol/L), the ABA content from 3.59 to 5.01 (ng/g FW), and the CK content from 4.01 to 4.56 (ng/g FW), for the optimum growth and restoration of P. euphratica indicated by the plant performance parameters and the efficiency of water application was the highest. The groundwater table in the studied region remained at -2.16 to -3.38 m, the proline content from 12.15 to 14.17 (mmol/L), the soluble sugar content from 154.71 to 183.16 (mmol/L), the ABA content from 2.78 to 4.86 (ng/g FW), and the CK content from 3.78 to 4.22 (ng/g FW), for the optimum growth and restoration of T. ramosissima indicated by the plant performance parameters and the efficiency of water application was the highest. The rational groundwater table for the restoration of vegetation in the studied region was at -3.15 to -3.38 m.

  9. Ecological Species Groups of Wetland Vegetation on Lianbotan in Fen River, Shanxi%汾河连伯滩湿地植被生态种组

    Institute of Scientific and Technical Information of China (English)

    焦磊; 张峰

    2011-01-01

    根据42个野外样方调查资料,采用Fisher精确检验、Pearson相关系数和Spearman秩相关系数,研究汾河连伯滩湿地21个优势种的种间关系,结合组平均法的聚类结果,对生态种组进行了划分.结果表明:1)在210个种对中,Fisher精确检验结果表明共有16个种对为正关联,1个种对为负关联;Pearson相关系数有20个种对为正相关,5个种对为负相关;Spearman秩相关系数有34个种对为正相关,7个种对为负相关;2)在所有的种对中,大多数种对间表现为不显著关联,种间不显著相关,说明优势种群间生态位相对分离;3)综合种间关联、种间相关和聚类分析结果,将21个优势种划分成4个生态种组,分别是芦苇生态种组、赖草生态种组、白茅生态种组和野艾蒿生态种组,这4个生态种组反映了随水分条件变化连伯滩湿地植被群落的组成特征.%Interspecies relationships between the dominant species of wetland vegetation on Lianbotan in Fen River,Shanxi by Fishers exact test, Pearson's correlation coefficient and Spearman's rank correlation based on the data collected from 42 field plots. Ecological species groups of those dominant species were studied by using group averaging clustering.The results indicated that: Sixteen species-pairs had positive association coefficient and one species-pair had negative association coefficient by Fisher's exact test. In addition, 20 species-pairs had positive correlation coefficient and 5 species-pairs had negative correlation coefficient by Pearson's correlation analysis. Furthermore, 34 species-pairs displayed positive and 7 were negative correlations by Spearman. Associations and correlations between most species-pairs were not significant, which suggested that the dominant species distributed in an isolated pattern and their inches separated. On the basis of the results of association and correlation of those dominant species as well as that of analysis of clustering, those

  10. Medium Scale Central Valley Riparian Vegetation and Land Use with Aggregated Delta Veg, 2011 [ds724

    Data.gov (United States)

    California Department of Resources — Geodatabase (SDE) feature class containing map of vegetation along mainstem rivers and major tributaries (including ancillary natural and semi-natural vegetation)...

  11. The spatial-temporal changes of vegetation coverage in the Three-River Headwater Region in recent 12 years%2000-2011年三江源区植被覆盖时空变化特征

    Institute of Scientific and Technical Information of China (English)

    刘宪锋; 任志远; 林志慧; 刘焱序; 张东海

    2013-01-01

    The Three-River Headwater Region is the source areas of the Yangtze River,the Yellow River,and the Lancang River.The region is not only of key importance to the ecological security of China.Due to climate change and human activities,ecological degradation occurred in this region.Therefore,"The nature reserve of Three-River Source Regions" was established,and "The project of ecological protection and construction for the Three-River Headwater Nature Reserve" was implemented by Chinese government.This study,based on MODIS-NDVI and climate data,aims to analyze the spatial-temporal changes of vegetation coverage and its driving factors in the Three-River Headwater Region between 2000 and 2011 from three dimensions.Linear regression,Hurst index and partial correlation analysis were employed.The results showed that:(1) In the past 12 years (2000-2011),the NDVI of the study area increased,with a linear tendency being 1.2%/10a,of which the Yangtze and the Yellow river source regions presented an increasing trend,while the Lancang River source region showed a decreasing trend.(2) Vegetation coverage presented an obvious spatial difference in the Three-River Headwater Region,and NDVI frequency was featured by a bimodal structure.(3) The vegetation coverage improved area was larger than the degraded area,being 64.06% and 35.94% respectively in the 12 years,and presented an increase pattem in the north and a decrease one in the south.(4) The reverse characteristic of vegetation coverage change is significant.In future,the degradation trends will be mainly found in the Yangtze River Basin and north of the Yellow River,while the improving trend areas are mainly distributed in the Lancang River Basin.(5) The response of vegetation coverage to precipitation and potential evapotranspiration has time lag,while the temperature does not have.(6) The increased vegetation coverage is mainly attributed to the warm-wet climate change and the implementation of the ecological

  12. Relationship of weed shiner and young-of-year bluegill and largemouth bass abundance to submersed aquatic vegetation in Navigation Pools 4, 8, and 13 of the Upper Mississippi River, 1998-2012

    Science.gov (United States)

    DeLain, Steven A.; Popp, Walter A.

    2014-01-01

    Aquatic vegetation provides food resources and shelter for many species of fish. This study found a significant relationship between increases in submersed aquatic vegetation (SAV) in four study reaches of the Upper Mississippi River (UMR) and increases in catch-per-unit-effort (CPUE) of weed shiners (Notropis texanus) and age-0 bluegills (Lepomis macrochirus) and largemouth bass (Micropterus salmoides) when all of the study reaches were treated collectively using Long Term Resource Monitoring Program (LTRMP) vegetation and fish data for 1998–2012. The selected fishes were more abundant in study reaches with higher SAV frequencies (Pool 8 and Lower Pool 4) and less abundant in reaches with lower SAV frequencies (Pool 13 and Upper Pool 4). When each study reach was examined independently, the relationship between SAV frequency and CPUE of the three species was not significant in most cases, the primary exception being weed shiners in Lower Pool 4. Results of this study indicate that the prevalence of SAV does affect relative abundance of these vegetation-associated fish species. However, the poor annual relationship between SAV frequency and age-0 relative abundance in individual study reaches indicates that several other factors also govern age-0 abundance. The data indicate that there may be a SAV frequency threshold in backwaters above which there is not a strong relationship with abundance of these fish species. This is indicated by the high annual CPUE variability of the three selected fishes in backwaters of Pool 8 and Lower Pool 4 when SAV exceeded certain frequencies.

  13. Response of soil heat-water processes to vegetation cover on the typical permafrost and seasonally frozen soil in the headwaters of the Yangtze and Yellow Rivers

    Institute of Scientific and Technical Information of China (English)

    HU HongChang; WANG GenXu; WANG YiBo; LIU GuangSheng; LI TaiBing; REN DongXing

    2009-01-01

    The response of soil temperature and moisture to vegetative cover in the active layer of permafrost and seasonally frozen soil were assessed and compared. Soil temperature and moisture, under a range of vegetation covers (92%, 65% and 30%) in the permafrost and vegetation covers (95%, 70%-80%, 40%-50% and 10%) in the seasonally frozen soil, were measured on a daily basis. A decline in vege-tation cover led to e decrease in the integral of freezing depth of active permafrost layer, but an in-crease in seasonally frozen soil. The maximum invasion depth and duration of the negative isotherm during the frozen period and of the positive isotherm during the non-frozen period clearly increased when vegetation cover declined. With a reduction of vegetation cover, the soil moisture in the active layer of the permafrost decreased for depths of 0.20-0.60 m, but increased for depths of 0.60-0.80 m, while for seasonally frozen soil, soil moisture of the entire profile (0.10-1.20 m) increased. Variation in vegetation cover alters soil heat-water processes, but the response to it is different between permafrost and seasonally frozen soil.

  14. Determining Regional Actual Evapotranspiration of Irrigated Crops and Natural Vegetation in the São Francisco River Basin (Brazil Using Remote Sensing and Penman-Monteith Equation

    Directory of Open Access Journals (Sweden)

    Antônio H. de C. Teixeira

    2010-05-01

    Full Text Available To achieve sustainable development and to ensure water availability in hydrological basins, water managers need tools to determine the actual evapotranspiration (ET on a large scale. Field energy balances from irrigated and natural ecosystems together with a net of agro-meteorological stations were used to develop two models for ET quantification at basin scale, based on the Penman-Monteith equation. The first model (PM1 uses the resistances to the latent heat fluxes estimated from satellite measurements, while the second one (PM2 is based on the ratio of ET to the reference evapotranspiration (ET0 and its relation to remote sensing parameters. The models were applied in the Low-Middle São Francisco river basin in Brazil and, after comparison against field results, showed good agreements with PM1 and PM2 explaining, respectively, 79% and 89% of the variances and mean square errors (RMSE of 0.44 and 0.34 mm d−1. Even though the PM1 model was not chosen for ET calculations, the equation for surface resistance (rs was applied to infer the soil moisture conditions in a simplified vegetation classification. The maximum values of rs were for natural vegetation—caatinga (average of 1,937 s m−1. Wine grape and mango orchard presented similar values around 130 s m−1, while table grape presented the lowest ones, averaging 74 s m−1. Petrolina and Juazeiro, in Pernambuco (PE and Bahia (BA states, respectively, were highlighted with the biggest irrigated areas. The highest increments are for vineyards and mango orchards. For the first crop the maximum increment was verified between 2003 and 2004 in Petrolina-PE, when the cultivated area increased 151%. In the case of mango orchards the most significant period was from 2005 to 2006 in Juazeiro-BA (129%. As the best performance was for PM2, it was selected and used to analyse the regional ET at daily and annual scales, making use of Landsat images and a geographic information system for different

  15. Observations of the vegetation of the Atigun River floodplain as affected by the crude oil spill from the Trans-Alaska Pipeline

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report is a summary of the results of botanical investigation conducted along the Atigun River, associated side channels and tributaries during the period 26 –...

  16. Productivity and phenological responses of natural vegetation to present and future inter-annual climate variability across semi-arid river basins in Chile.

    Science.gov (United States)

    Glade, Francisco E; Miranda, Marcelo D; Meza, Francisco J; van Leeuwen, Willem J D

    2016-12-01

    Time series of vegetation indices and remotely sensed phenological data offer insights about the patterns in vegetation dynamics. Both are useful sources of information for analyzing and monitoring ecosystem responses to environmental variations caused by natural and anthropogenic drivers. In the semi-arid region of Chile, climate variability and recent severe droughts in addition to land-use changes pose threats to the stability of local ecosystems. Normalized difference vegetation index time series (2000-2013) data from the moderate resolution imaging spectroradiometer (MODIS) was processed to monitor the trends and patterns of vegetation productivity and phenology observed over the last decade. An analysis of the relationship between (i) vegetation productivity and (ii) precipitation and temperature data for representative natural land-use cover classes was made. Using these data and ground measurements, productivity estimates were projected for two climate change scenarios (RCP2.6 and RCP8.5) at two altitudinal levels. Results showed negative trends of vegetation productivity below 2000 m a.s.l. and positive trends for higher elevations. Phenology analysis suggested that mountainous ecosystems were starting their growing period earlier in the season, coinciding with a decreased productivity peak during the growing season. The coastal shrubland/grassland land cover class had a significant positive relation with rainfall and a significant negative relation with temperature, suggesting that these ecosystems are vulnerable to climate change. Future productivity projections indicate that under an RCP8.5 climate change scenario, productivity could decline by 12% in the period of 2060-2100, leading to a severe vegetation degradation at lower altitudes and in drier areas.

  17. Análise das modificações da cobertura vegetal da planície fluvial do alto rio Paraná no período entre 1976 e 2007 = Analysis of vegetation changes in the Paraná river floodplain between 1976 and 2007

    Directory of Open Access Journals (Sweden)

    Edivando Vitor Couto

    2011-04-01

    Full Text Available A vegetação da planície fluvial do rio Paraná sofre a pressão da ocupação antrópica desde a década de 1950. A área próxima a Porto Rico (Paraná tem sido estudada desde os anos 1980, mas não há estudos dirigidos à distribuição espacial da vegetação. Os objetivos deste trabalho são cartografar as unidades vegetais e verificar a evolução temporal de sua distribuição entre 1976 e 2007. Para isso foram utilizadas imagens orbitais de 1976 (LANDSAT MSS-1, 1987 (LANDSAT TM-5, 2000 (LANDSAT ETM+7 e de 2007 (CBERS-2 CCD. Asimagens foram georreferenciadas e classificadas pelo algoritmo Bhattacharya. Foram identificadas três classes de vegetação, corpos de água e áreas de solo exposto. A análise multitemporal demonstrou aumento contínuo da área de solo exposto, aumento da área dos corpos de água, mudança de posição das áreas úmidas no período entre 1976 e 1987 e modificações mais sutis de ambas as classes no período entre 1987 e 2007. As áreas de vegetação arbórea diminuíram em quase todos os anos. Tais dados permitem afirmar que a atuação antrópica sobre a planície vem se ampliando e que as principais cheias modificaram sua morfologia.The removal of vegetation from the Paraná river floodplain has been increasing since the 1950s the until present time, but no study has been made about its spatial distribution. The purpose of this paper is to map and analyze the temporal evolution of vegetation distribution over the Parana river floodplain between 1976 and 2007. Orbital images from 1976 (LANDSAT MSS-1, 1987 (LANDSAT TM-5, 2000 (LANDSAT ETM+7 and 2007 (CBERS-2 CCD were utilized to compare the evolution of the vegetation distribution over that time period. Theimages were georeferenced using SPRING 4.3.3 software and classified by the Bhattacharya algorithm; the maps were produced using the Global Mapper 7.4 software. Three different classes of vegetation, water bodies and exposed soil areas were

  18. 沉水植被对河道悬沙输运过程影响试验研究%Experimental study on impact of submerged vegetation on suspended load transport in urban rivers

    Institute of Scientific and Technical Information of China (English)

    武迪; 庞翠超; 赖锡军; 汪德爟

    2013-01-01

    The suspended load in rivers affects the survival and growth of animals and plants, and causes ecological pollution as well, threatening the health of river ecosystem. The aquatic vegetation can mitigate the ecological threat caused by suspended load. In order to explore the mechanism of environmental and ecological effect of aquatic vegetation and make full use of it, we carried out laboratory experiments in a flume; the principles of sediment incipient motion inhibition, sediment transport slow-down, and sediment stop acceleration by submerged vegetation were explained from the aspects of time-average velocity, turbu-lence intensity and shear stress, etc. . The experimental results showed that in the range of plant density in the experiments, the relationship between plant density and suspended sediment settling rate was non-linear. Therefore, when the submerged vegeta-tion ( tape grass) is applied in the regulation of suspended sediment flow, appropriate plant density should be adopted so as to fully realize its effect and save the cost.%河流悬沙可影响水体中动、植物生存和生长,并造成生态污染,威胁河道生态系统的健康。水生植被可以减缓悬沙带来的生态危害。为了探求水生植被环境和生态效应的产生机理,并使其更有效地发挥作用,开展了室内水槽试验,从时均流速、紊动强度、切应力等方面,科学解释了沉水植被抑制泥沙起动、减缓泥沙运输、加快泥沙止动的原理。试验表明,在所研究的植株密度范围内,植株密度与对悬沙沉降并不成线性比例。因此,沉水植被(苦草)用于治理水流悬沙时,可适度选取植株密度,使其既发挥治理成效,又节约经济成本。

  19. 连续可调式沉水植物网床对河道水质的修复%Bioremediation of river water quality by consecutively adjustable submerged vegetation net

    Institute of Scientific and Technical Information of China (English)

    吴海龙; 霍元子; 邵留; 王阳阳; 于克锋; 何培民; 温文科

    2012-01-01

    A series of consecutively adjustable submerged vegetation nets were constructed in a polluted shallow river with a length of about 200 m and nearby the water resource protection area of Taihu Lake in East China, forming an aquatic vegetation consisted of submerged plant species Ca-bomba caroliniana, Vallisneria natans, Elodea nuttallii, Hydrilla verticillata, and Potamogeton cris-pus. The water quality indices including total nitrogen (TN), ammonium nitrogen (NH4+-N) , nitrite nitrogen (NO2--N) , nitrate nitrogen (NO3--N) , total phosphorus (TP) , and phosphate (PO43-P) were monitored, and the bioremediation effect of the vegetation nets was evaluated. After setting up the vegetation nets, the Secchi depth (SD) of the river changed from 0.5 m to 1.7-1.8 m, and the TN and TP concentrations 15 and 20 days after the nets constructed decreased by 35. 6% and 66.3% , and 29.4% and 63. 2% , respectively. After five months, the concentrations of NH4+ -N, NO2--N, NO3--N, TN, TP, and PO43-P decreased by 92. 4% , 76. 8% , 72. 7% , 73.9% , 90. 5% , and 92. 0% , respectively. This study showed that consecutively adjustable submerged vegetation net could be a potential approach for treating polluted river waters, particularly for the bioremediation of polluted small landscape shallow water bodies.%在太湖贡湖水源保护区陆域的一条长约200 m的污染河道内构建了一系列连续可调式沉水植物网床,形成了以菊花草、苦草、伊乐藻、轮叶黑藻和菹草等沉水植物构成的水生植物群落;跟踪监测了总氮(TN)、铵态氮(NH4 +-N)、亚硝态氮(NO2--N)、硝态氮(NO3--N)、总磷(TP)和磷酸盐(PO43--P)等水质指标,分析沉水植物网床引导沉水植被恢复对污染河道的水质修复效果.结果表明:沉水植被网床构建后,水体透明度显著升高,由修复前的0.5m提高到1.7 ~1.8 m;在沉水植被网床构建后的第5天和第20天,TN和TP的削减率分别为35.6%、66.3%和29.4%、63.2%;5

  20. Geology of the Johnson River Area Alaska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The vegetation, topography, and geology of the Johnson River area are representative of the entire eastern interior region of Alaska. This area has a vegetational...

  1. Delta Vegetation and Land Use [ds292

    Data.gov (United States)

    California Department of Resources — Vegetation and land use are mapped for the approximately 725,000 acres constituting the Legal Delta portion of the Sacramento and San Joaquin River Delta area....

  2. Hydrologic requirements of and consumptive ground-water use by riparian vegetation along the San Pedro River, Arizona. Chapters A-D.

    Science.gov (United States)

    Leenhouts, James M.; Stromberg, Juliet C.; Scott, Russell L.; authors include Leenhouts, James M.; Lite, Sharon J.; Dixon, Mark; Rychener, Tyler; Makings, Elizabeth; Williams, David G.; Goodrich, David C.; Cable, William L.; Levick, Lainie R.; McGuire, Roberta; Gazal, Rico M.; Yepez, Enrico A.; Ellsworth, Patrick; Huxman, Travis E.

    2006-01-01

    This study is a coordinated effort by the U.S. Geological Survey (USGS), the U.S. Department of Agriculture, Agricultural Research Service (USDA ARS), and Arizona State University, with assistance from the U.S. Army Corps of Engineers, the University of Wyoming, and the University of Arizona. The specific objectives of the study were: to determine the water needs of riparian vegetation through the riparian growing season and throughout the SPRNCA to ensure its long-term ecological integrity; to quantify the total water use of riparian vegetation within the SPRNCA; and to determine the source of water used by key riparian plant species within the SPRNCA. To meet these objectives, the study was divided into three elements: (1) a characterization of the status and variability of hydrologic factors within the riparian system (USGS), (2) a riparian biohydrology study to relate spatial and temporal aspects of riparian changes and condition to the hydrologic variables (Arizona State University), and (3) a water-use evapotranspiration (ET) study to quantify annual consumptive ground-water use by riparian transpiration and direct evaporation from the stream channel (USDA ARS) in cooperation with the U.S. Army Corps of Engineers, the University of Wyoming, and the University of Arizona. Twenty-six sites within the SPRNCA were selected for collection of vegetation data from three primary streamflow regimes (perennial, intermittent-wet, intermittent-dry), which include the principal vegetation communities. Detailed hydrologic-condition data were collected at a subset of 16 of these sites, called the SPRNCA biohydrology sites. Water-use and water-source data were collected at a subset of 5 of the 16 biohydrology sites. Vegetation data also were collected at supplemental sites within the SPRNCA boundary in the Upper San Pedro Basin and in the Lower San Pedro Basin. In addition to information about vegetation and geomorphic conditions, hydrologic data collected at the 16

  3. Generic index of aquatic vegetation (IVAM) for a rapid assessment of ecological quality of Spanish rivers: taxonomic resolution and application to Castilla-La Mancha region; Indice Generico de Vegetacion Acuatica (IVAM): Propuesta de evaluacion rapida del estado ecologico de los rios ibericos en aplicacion de la Directiva Marco del Agua

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, J. L.; Navarro, C.; Hera, J. de las

    2005-07-01

    The Water Framework Directive proposes the use of aquatic flora as a valid bio indicator for assessing the ecological status of European rivers. Due to the lack of an aquatic vegetation index for Spanish rivers, we present an index to assess trophic status or eutrophication in rivers and streams. Thus, we calculated tolerance scores and indicator values for tax from nutrient levels. the index is called IVAM (Macroscopic Aquatic Vegetation Index). The index takes into account either macrophyte or microphytes (the latter making up macroscopic growth forms) including briophytes. The IVAM showed the best correlation with nutrients besides other quality indices, indicating a solid tool to assess trophic status or eutrophication. (Author) 15 refs.

  4. Presettlement Vegetation

    Data.gov (United States)

    Minnesota Department of Natural Resources — Presettlement vegetation of Minnesota based on Marschner's original analysis of Public Land Survey notes and landscape patterns. Marschner compiled his results in...

  5. Water scarcity-induced change in vegetation cover along Teesta River catchments in Bangladesh : NDVI, Tasseled Cap and System dynamics analysis

    OpenAIRE

    Rahman, Md. Azizur

    2013-01-01

    Water scarcity is both natural and man-made phenomenon. Water control and uneven distribution of upstream TeestaRiver water makes artificial scarcity in downstream areas which can be minimized at least to the water stress level by balancing distribution and sustainable water use. Tasseled Cap transformation and NDVI methods were used in this study in order to find the magnitude of water scarcity in the downstream areas. NDVI and Tasseled Cap Greenness methods were applied to get proxy for soi...

  6. Characterization of abiotic conditions affecting vegetation distribution in the river Plate coastal plain, Argentina - DOI: 10.4025/actascibiolsci.v30i4.5875

    Directory of Open Access Journals (Sweden)

    Omar Raúl Marínez

    2008-11-01

    Full Text Available The river Plate coastal plain is located in northeastern Buenos Aires province, where geological events such as sea transgressions and regressions in the Holocene have produced a stratigraphic column with marine-estuarine, fluviatile and continental sediments, as well as a variety of landforms and soils. The aim of this paper is to describe these different coastal settings and their influence in the distribution of plant communities.

  7. Flora y vegetación del valle superior del Rió Atuel (Mendoza-Argentina Flora and vegetation of the Upper Valley of the Atuel River (Mendoza-Argentina

    Directory of Open Access Journals (Sweden)

    Ernesto A Morici

    2010-06-01

    Full Text Available El valle superior del Río Atuel presenta variaciones altitudinales y topográficas, siendo un territorio de confluencia de elementos propios de las provincias fitogeográficas Andina, del Monte, de la estepa Patagónica y de la Payunia. En este trabajo se estudia su flora y vegetación, a través de censos florísticos siguiendo la metodología de Braun-Blanquet (1979. A partir de la matriz de especies por censos se determinó el espectro biológico ponderado y la diversidad florística. Además, se estimó la cobertura basal registrándose los porcentajes de vegetación, broza, suelo desnudo, roca y fragmentos de roca. El estudio se desarrolló en un área restringida a la vertiente norte del Río Atuel entre su intersección con la Ruta Nacional 40 y las inmediaciones de la Planta de Azufre. En los censos se registraron un total de 89 especies pertenecientes a 36 familias, siendo las más numerosas Asteraceae, Poaceae, Verbenaceae, Fabaceae y Solanaceae. El 96% de las especies son nativas y sólo el 4% exóticas. Se diferenciaron 15 comunidades: 12 matorrales, 1 pastizal, 1 herbazal y 1 estepa de cojines.In this study we present a description of the flora and vegetation of the upper valley of Rio Atuel, Mendoza Province. In this area, characteristic taxa fron the Andina, Monte, Payunia and Patagonia Phytogeographical Provinces overlap their ranges. Considering that Atuel river high valley shows relevant altitudinal and topographical variations and a confluence of typical components from Andina, Monte, Patagonia and Payunia phytogeographic provinces, we plained to study, flora and vegetation. Floristic censuses were performed according to Braun-Blanquet (1979 and the matrix at coverage species was used to obtain cover data, weighted biological spectrum and floristic diversity. Furthermore, basal cover was estimated and vegetation, litter, bare soil, stones and stone pieces were recorded. This research was developed in an area restricted to the

  8. Soil seed bank and aboveground vegetation in Jinshajing Hot-Dry River Valley Hillslope vegetation restoration site%金沙江干热河谷山地植被恢复区土壤种子库和地上植被研究

    Institute of Scientific and Technical Information of China (English)

    罗辉; 王克勤

    2006-01-01

    Soil seed bank plays an important role in the composition of different plant communities and especially in their conservation. Although Soil seed bank, aboveground vegetation and their relationship have been the subject of much recent attention, little is known about the size and species composition of soil seed bank and aboveground vegetation in semi-arid hillslope grasslands and understanding of how these components interact to determine the importance of seed banks to regeneration is limited.We assessed the size and species composition of a soil seed bank and aboveground vegetation in an experiment with 36 vegetation quadrats and 108 soil samples in terrace, slope, gully and grazing land that represent a range of habitats within a hillslope grassland in Jinshajing hot-dry river valley of Yunnan. Terrace, slope and gully represent restored site and grazing land typifies unrestored site. We identified 21 taxa in the seed bank with a median of 7 species/m2 and a median density of 5498 seeds/m2, while in aboveground vegetation, 19 species were observed with a median of 6 species/m2 and a median density of 1088 plants/m2. Both seed bank density and aboveground vegetation density among grazing land, gully, slope and terrace differed significantly. There was an absolutely high proportion of herbaceous species in the seed bank and aboveground vegetation. Gramineae predominated over both seed bank and vegetation. The most frequent seeds and plants were Bothriochloa pertusa (L.) A. Camus and Heteropogon contortus (L.) Beauv that had the highest individual number, importance value and biomass. In the seed bank, the seeds of Bothriochloa pertusa (L.) A. Camus and Heteropogon contortus (L.) Beauv accounted for 50.68% and for 33.10% of the total seeds respectively. In aboveground vegetation, the individual number of Bothriochloa pertusa (L.) A. Camus accounted for 55.66% of the total and Heteropogon contortus (L.) Beauv accounted for 29.86%. The biomass of Bothriochloa

  9. Riparian vegetation affected by bank erosion in the Lower São Francisco River, Northeastern Brazil Vegetação ciliar afetada pela erosão na margem do baixo São Francisco, Nordeste do Brasil

    Directory of Open Access Journals (Sweden)

    Francisco Sandro Rodrigues Holanda

    2005-04-01

    Full Text Available Changes in the hydrological regime of the Lower São Francisco River, located in Northeastern Brazil have brought negative environmental impacts, jeopardizing the flora and fauna of a global biodiversity hotspot, due to implementation of hydroelectric power dams and surface water withdrawal for irrigation in public and private perimeters. Remnants of the riparian stratum associated to the riverbank destabilization in six fragments were studied by surveying trees, shrubs, herbs, and aquatic species. The calculation of the Factor of Safety (FS was performed in order to understand the riverbank's stability related to soil texture and vegetation cover. An overall number of 51 botanic families distributed in 71 genera and 79 species were recorded, predominantly from the families Mimosaceae, Myrtaceae, and Fabaceae. The fragmented riparian vegetation is mostly covered by secondary species under a strong anthropogenic impact such as deforestation, mining and irrigation, with an advanced erosion process in the river margins. Strong species that withstand the waves present in the river flow are needed to reduce the constant landslides that are mainly responsible for the river sedimentation and loss of productive lands. A lack of preservation attitude among the local landholders was identified, and constitutes a continuing threat to the riparian ecosystem biodiversity.Mudanças no regime hidrológico no baixo curso do rio São Francisco, localizado na Região Nordeste do Brasil, trouxeram impactos negativos, como a ameaça à fauna e à flora em um dos 25 "hotspots" do mundo para a conservação da biodiversidade, em razão da construção de usinas hidroelétricas e retiradas de água para irrigação em perímetros de irrigação públicos e privados. Foram estudados remanescentes da vegetação ciliar associados com a desestabilização dos barrancos do rio, em seis fragmentos de mata, por meio de levantamento florístico e histórico de degrada

  10. 黄河中游植被变化对水量转化的影响分析%Impact of Vegetation Change on Water Transformation in the Middle Yellow River

    Institute of Scientific and Technical Information of China (English)

    刘昌明; 李艳忠; 刘小莽; 白鹏; 梁康

    2016-01-01

    基于遥感数据分析了黄河中游植被变化特征,借助自主构建的HIMS⁃VIH模型,模拟了黄河中游11个子流域1980—2013年的蓝水—绿水动态转化过程。结果显示,与退耕还林(草)工程实施前相比,2000年以来11个子流域的叶面积指数( LAI)、归一化植被指数( NDVI)均呈增大趋势,其中以河口镇—龙门区间变化最为显著。对蓝水(径流)而言,与1980—1999年相比,2000—2013年大部分子流域的径流和径流系数显著减小。植被的增加导致绿水(蒸散发)明显增加,从而使蓝水下降。随着1999年以来水土保持措施大幅度的持续实施,目前黄河中游水热条件与植被状况已达到一个阶段性相对稳定状态,如果退耕还林(草)等水土保持措施维持现状,那么今后林草植被耗水将随气候(降水)变化而波动并维持在一定的水平,黄河水量可能会因水热条件的制约而不再大幅度地减少。%The dynamic transformation of blue and green water was simulated in the eleven sub⁃catchments in the middle Yellow River based on the characteristics of vegetation change and the independent construction model of Hydro⁃Informatic Modeling System Vegetation Impacts on Hydrology (HIMS⁃VIH). The results show that the Leaf Area Index (LAI) and Normalized Difference Vegetation Index (NDVI) in all sub⁃catchments increase, especially in the Hekouzhen⁃Longmen reach since the year of 2000. Compared with the period of 1980-1999, the blue water ( runoff and runoff coefficient ) in most sub⁃catchments decreases significantly during 2000 - 2013. The green water (evapotranspiration) increases significantly due to the vegetation recovery strategies and causes the blue water (runoff) decrease. As the larger scale and continued implementation of conservation measures, we argue it has reached a relative stable state between the hydrothermal and vegetation conditions. If the

  11. Análise espaço-temporal da cobertura vegetal e uso da terra na Interbacia do Rio Paraguai Médio-MT, Brasil Spatio-temporal analysis of vegetation cover and land use in the middle Paraguay River Interbasin-MT, Brazil

    Directory of Open Access Journals (Sweden)

    Seyla Poliana Miranda Pessoa

    2013-02-01

    Full Text Available O objetivo deste estudo foi realizar uma análise espaço-temporal da cobertura vegetal e do uso da terra na Interbacia do Rio Paraguai Médio-MT, Brasil, pelo geoprocessamento de imagens Landsat TM, dos anos 1991, 2001 e 2011. As imagens foram georreferenciadas, classificadas e processadas no software Spring e as classes temáticas, quantificadas e editadas no software ArcGis. Foram mapeadas sete classes, sendo as mais expressivas a vegetação nativa, a pastagem e a cana-de-açúcar. Os resultados indicaram alterações em todas as classes durante os últimos 20 anos, com a diminuição de 22,89% da vegetação nativa, relacionada com o aumento de 58,42% da pastagem e 490,26% de monocultura de cana-de-açúcar. Foi verificado o conflito de uso da terra, principalmente em áreas de mata ciliar, fato que pode influenciar negativamente na conservação da interbacia e, consequentemente, do pantanal mato-grossense.This study analyzed spatial and temporal land use changes in the Middle Paraguay River Interbasin-MT, Brazil using Landsat images from 1991, 2001 and 2011. Images were geo-referenced, classified and processed using Spring software, and thematic classes were edited and quantified using ArcGis software. Seven map classes were identified, and native vegetation, pasture and sugarcane were the most significant ones. The results showed changes in all classes during the past 20 years, primarily a 22.89% decrease of native vegetation, a 58.42% increase in pasture and 490.26% increase of sugarcane monoculture. We verified land use conflicts, mostly in riparian areas, which may negatively influence Interbasin and, consequently, Pantanal conservation in the State of Mato Grosso, Brazil.

  12. 中国内陆河流域植被对气候变化的敏感性差异%Sensitivity analyses of different vegetations responding to climate change in inland river basin of China

    Institute of Scientific and Technical Information of China (English)

    HOU Peng; WANG Qiao; CAO Guangzhen; WANG Changzuo; ZHAN Zhiming; YANG Bingfeng

    2012-01-01

    @@%Terrestrial ecosystem and climate system are closely related to each other.Faced with the unavoidable global climate change,it is important to investigate terrestrial ecosystem responding to climate change.In inland river basin of arid and semi-arid regions in China,sensitivity difference of vegetation responding to climate change from 1998 to 2007 was analyzed in this paper.(1) Differences in the global spatio-temporal distribution of vegetation and climate are obvious.The vegetation change shows a slight degradation in this whole region.Degradation is more obvious in densely vegetated areas.Temperature shows a general downward trend with a linear trend coefficient of-1.1467.Conversely,precipitation shows an increasing trend with a linear trend coefficient of 0.3896.(2) About the central tendency response,there are similar features in spatial distribution of both NDVI responding to precipitation (NDVI-P) and NDVI responding to AI (NDVI-AI),which are contrary to that of NDVI responding to air temperature (NDVI-T).Typical sensitivity region of NDVI-P and NDVI-AI mainly covers the northern temperate arid steppe and the northern temperate desert steppe.NDVI-T typical sensitivity region mainly covers the northern temperate desert steppe.(3) Regarding the fluctuation amplitude response,NDVI-T is dominated by the lower sensitivity,typical regions of the warm temperate shrubby,selui-shrubby,bare extreme dry desert,and northern temperate meadow steppe in the east and temperate semi-shrubby,dwarf arboreous desert in the north are high response.(4) Fluctuation amplitude responses between NDVI-P and NDVI-AI present a similar spatial distribution.The typical sensitivity region mainly covers the northern temperate desert steppe.There are various linear change trend responses of NDVI-T,NDVI-P and NDVI-AI.As to the NDVI-T and NDVI-AI,which are influenced by the boundary effect of semi-arid and semi-humid climate zones,there is less correlation of their linear change tendency

  13. 黄河三角洲盐碱地混交林林下植被现状%Study on Understory Vegetation of the Mixed Plantations on Saline-Alkali Soil in Yellow River Delta

    Institute of Scientific and Technical Information of China (English)

    姚秀粉; 马风云; 辛贺; 侯宝顺

    2012-01-01

    The species of understory vegetation in different mixed plantations, the biodiversity, biomass and growth status under different salt content in the soil in the saline-alkali area in Yellow River delta were studied by sample plot survey. Totally 31 understory plant species were recorded, which belonged to 31 genera and 14 families. Among which, there were 10 species from gramineous family, accounting for the largest proportion. The dominant species of understory vegetation in la, 3a, 7a and 22a mixed plantations were Phrag-mites australis + Artemisia selengensis , Ixerh polycephala + Chenopodium album + Setaira viridis, Plantago asiatica, and Cleistogenes squarrosa respectively. There were few understory vegetation species with low biodiversity , less enriched species and more sparse species. The aboveground biomass of the understory vegetation species was generally greater than that of the underground. The dominate species in the mixed plantations with high salt content were mainly the salt tolerant plant species, and vice versa. Because of the strong adaptability to different environmental conditions, Ixeris polycephala and Chenopodium album grew well on sites with four different salt content levels.%采用样方调查的方法,研究了黄河三角洲盐碱地不同混交林林下植被的种类、生物多样性、生物量及不同土壤盐分林下植被的生长状况.共记录到林下植被31种,隶属于14科31属,其中禾本科最多,为10种;1、3、7、22龄林下植被的优势种分别为芦苇和芦蒿、苦荬菜+灰菜+狗尾草、车前草、韩式隐子草;林下植被的物种并不丰富,生物多样性不高,且富集种少,稀疏种多,地上部分生物量皆大于地下;土壤盐分含量高时,林下植被以耐盐碱植物为主,反之亦然,且由于苦买菜和灰菜具有较强的适应能力,在4个不同土壤盐分含量下都有生长.

  14. Winter vegetation composition and the purification effect of a cascaded wetland along the Jialu River%贾鲁河梯级河滩湿地冬季植被构建及净化效果研究

    Institute of Scientific and Technical Information of China (English)

    郭萧; 叶许春; 俞士敏; 李文朝

    2011-01-01

    在地处黄河之滨的河南郑州建设运行梯级河滩湿地净化贾鲁河水,技术示范工程在2009年夏、秋季节取得了良好的水质净化效果,为了验证冬季沉水植物对水质净化的效果,用菹草、伊乐藻、西伯利亚鸢尾等耐低温植物组建冬季湿地植被,研究了冬季植被的发育情况和水质净化效果.结果表明,菹草和伊乐藻这两种沉水植物能够在冬季湿地中成活并发育形成覆盖度最高达50%的植被,西伯利亚鸢尾全部成活并能发出新叶.在水力负荷为140 mm·d-1的连续运行状态下,湿地对河水中TN、TP、NH4+-N和CODcr的平均去除率分别为32%、67%、55%和29%,并且随着冬季植被的逐渐发育净化效果得到加强.冬季城市排水中的余热可以为在接纳河流中开展河滩梯级湿地水质净化提供有利条件,适当增加水深并利用菹草、伊乐藻等耐寒植物组建沉水植被是可行的.%A cascaded surface-flow constructed wetland with a total area of 7400 m , was constructed along the Jialu River floodplain in Zhengzhou city of Henan province. The substrate was high viscosity silt loam. The purification effect of the cascaded wetland was excellent in summer and autumn of 2009, then winter vegetation was composed with Potamogeton crispus, Elodea canadensis and Iris sibirica and the vegetation development and purification effect were observed continuously. Potamogeton crispus and Elodea canadensis survived and vegetation coverage stood at 50% . Iris sibirica all survived and issued new leaves. Our results indicated that the average removal rates of nitrogen, phosphorus, ammonia and CODCr were 32% , 67% , 55% and 29% respectively with hydraulic loading of 140 mm·d-1 . The purification effect was strengthened with the gradual development of the vegetation. This study demonstrated that a wetland with reasonable winter aquatic plants and species composition can ultimately improve the

  15. Kuchler Vegetation

    Data.gov (United States)

    California Department of Resources — Digital version of potential natural plant communites as compiled and published on 'Map of the Natural Vegetation of California' by A. W. Kuchler, 1976. Source map...

  16. Wieslander Vegetation

    Data.gov (United States)

    California Department of Resources — Digital version of the 1945 California Vegetation Type Maps by A. E. Wieslander of the U.S. Forest Service. Source scale of maps are 1:100,000. These compiled maps...

  17. Distribution of antibiotics in wastewater-irrigated soils and their accumulation in vegetable crops in the Pearl River Delta, southern China.

    Science.gov (United States)

    Pan, Min; Wong, Chris K C; Chu, L M

    2014-11-19

    Wastewater is increasingly being used to irrigate agricultural land in many countries around the world. However, limited research has examined the occurrence of antibiotics in soil irrigated with wastewater and their accumulation in plants. This study aimed to determine the distribution of various types of antibiotics in different environmental matrices in the Pearl River Delta (PRD) region and to evaluate their accumulation and translocation in edible crops. Samples were collected from six sites in the PRD where either domestic wastewater or fishpond water was used for irrigation. Results showed that fishpond water irrigated soils had higher concentrations of antibiotics than wastewater-irrigated soils. Different trends were observed in the accumulation of antibiotics in the different edible parts of various crops. Despite the low human annual exposure to antibiotics through the consumption of edible crops (1.10 to 7950 μg/y), the potential adverse effects of antibiotics along the food chain should not be neglected.

  18. 基于SPOT-VGT数据的流域植被覆盖动态变化及空间格局特征——以淮河流域为例%Dynamic changes and spatial patterns of vegetation cover in a river basin based on SPOT-VGT data:A case study in the Huaihe River Basin

    Institute of Scientific and Technical Information of China (English)

    王情; 刘雪华; 吕宝磊

    2013-01-01

    To investigate the dynamic changes and spatial patterns of vegetation in the Huaihe River Basin, this study used SPOT-VGT NDVI (Normalized Different Vegetation Index) data and land use/cover data to analyze the spatial-temporal patterns of vegetation change in the region during 1999 to 2007 by using ArcGIS Spatial analysis tools. The results showed that: (1) SPOT-VGT data, combined with GIS Spatial analysis tools and models, can be used in the calculation and analysis of vegetation cover conditions in river basin scale; (2) NDVI maintained an clearly increasing trend in most areas (71.33%) of the Huaihe River Basin during 1999-2007, suggesting that the vegetation coverage was improved in the region in the last decade, which indicated that the measures of vegetation protection and restoration had achieved positive results; (3) Monthly NDVI variations showed a double-peak curve. The two peaks appeared in April and August respectively, and the peak in April was lower than that in August; (4) The average NDVI showed obvious spatial variations. NDVI in the plain areas was higher than that in the mountain areas, and it was higher in the north areas of Huaihe River than in the south areas; NDVI varied greatly in the mountain areas, with the highest average value in the Dabieshan Mountain and the lowest in the Yimengshan Mountain. Areas in and around the cities had lower NDVI due to high density of built-up land. The areas with relatively poor vegetation coverage had high risk of soil erosion. (5) The NDVI changing trends varied among different land use/cover types. The average NDVI values of cropland, woodland, grassland and alkaline land had shown a stable increasing trend during 1999-2007. The average NDVI of flooded plains land showed a slightly increasing trend. The NDVI of marshes fluctuated dramatically. The results of the studies of dynamic changes and spatial patterns of vegetation in the Huaihe River Basin can provide a scientific basis for planning and taking

  19. Vegetation establishment in convectively accelerated streams

    Science.gov (United States)

    Crouzy, B.; McLelland, S. J.; Molnar, P.; Camporeale, C.; Perona, P.

    2013-12-01

    We study the conditions for vegetation establishment within river reaches with converging boundaries. Common to many such rivers worldwide is the existence of a limiting front (e.g., Figure 1a) beyond which all the riverbed vegetation is uprooted by flooding events. There are however exceptions, which leads to an interesting ecomorphodynamic problem (existence and position of the front). We use a theoretical 1-D framework based on morphodynamic equations modified in order to account for the presence of vegetation (Perona et al., submitted), and obtain the link between the position of the vegetated front and river eco-hydraulic variables under steady and unsteady conditions. We apply our framework to a number of flume experiments (unsteady flow) where Avena sativa L. (common oat) seedlings grow subject to periodic flow disturbances within a convergent flume channel (Figure 1b). We find that depending on the outcome of the competition between hydrological and biological processes there is either a limiting spatial front within the convergent section beyond which vegetation cannot survive, or vegetation colonizes the entire riverbed. The existence and the position of the front depend on the ability for vegetation to take root efficiently and withstand uprooting by the flow of the convectively accelerated stream (Crouzy et al., in press). The active role of vegetation and of unit streampower in this particular ecomorphodynamic process are then discussed in relation to the conceptual model of Gurnell and Petts (2006), and under the light of our theoretical and experimental results. REFERENCES - Crouzy, B., K. Edmaier, N. Pasquale and P. Perona (in press). Impact of floods on the statistical distribution of riverbed vegetation. Geomorphology doi:10.1016/j.geomorph.2012.09.013. - Gurnell A., Petts G. (2006). Trees as riparian engineers: The Tagliamento River, Italy. Earth Surface Processes and Landforms, 31: 1558--1574. - Perona, P., B. Crouzy, S. Mc Lelland, P. Molnar

  20. Late Quaternary vegetation and climate history of a perennial river canyon in the Rīo Salado basin (22°S) of Northern Chile

    Science.gov (United States)

    Latorre, Claudio; Betancourt, Julio L.; Arroyo, Mary T.K.

    2006-01-01

    Plant macrofossils from 33 rodent middens sampled at three sites between 2910 and 3150 m elevation in the main canyon of the Rīo Salado, northern Chile, yield a unique record of vegetation and climate over the past 22,000 cal yr BP. Presence of low-elevation Prepuna taxa throughout the record suggests that mean annual temperature never cooled by more than 5°C and may have been near-modern at 16,270 cal yr BP. Displacements in the lower limits of Andean steppe and Puna taxa indicate that mean annual rainfall was twice modern at 17,520-16,270 cal yr BP. This pluvial event coincides with infilling of paleolake Tauca on the Bolivian Altiplano, increased ENSO activity inferred from a marine core near Lima, abrupt deglaciation in southern Chile, and Heinrich Event 1. Moderate to large increases in precipitation also occurred at 11,770-9550 (Central Atacama Pluvial Event), 7330-6720, 3490-2320 and at 800 cal yr BP. Desiccation occurred at 14,180, 8910-8640, and 4865 cal yr BP. Compared to other midden sites in the region, early Holocene desiccation seems to have happened progressively earlier farther south. Emerging trends from the cumulative midden record in the central Atacama agree at millennial timescales with improved paleolake chronologies for the Bolivian Altiplano, implying common forcing through changes in equatorial Pacific sea-surface temperature gradients.

  1. Wetland vegetation establishment in L-Lake

    Energy Technology Data Exchange (ETDEWEB)

    Kroeger, S.R.

    1990-07-01

    Wetland vegetation was transplanted from PAR Pond to L-Lake between January and August, 1987. Approximately 100,000 individual plants representing over 40 species were transplanted along the southern shoreline. Three zones of vegetation were created: (1) submersed/floating-leaved, (2) emergent, (3) upper emergent/shrub. During the summers of 1987, 1988, 1989, the Savannah River Ecology Laboratory sampled the vegetation in 54 permanent transects located in planted (N=32) and unplanted areas (N=22). The 1989 vegetation data from L-Lake were compared to 1985 data from PAR Pond.

  2. VEGETATION MAPPING IN WETLANDS

    Directory of Open Access Journals (Sweden)

    F. PEDROTTI

    2004-01-01

    Full Text Available The current work examines the main aspects of wetland vegetation mapping, which can be summarized as analysis of the ecological-vegetational (ecotone gradients; vegetation complexes; relationships between vegetation distribution and geomorphology; vegetation of the hydrographic basin lo which the wetland in question belongs; vegetation monitoring with help of four vegetation maps: phytosociological map of the real and potential vegetation, map of vegetation dynamical tendencies, map of vegetation series.

  3. Caracteres anatómicos de la vegetación costera del Río Salado (Noroeste de la provincia de Buenos Aires, Argentina Anatomic features of Salado river coastal vegetation (Northwest of Buenos Aires Province, Argentina

    Directory of Open Access Journals (Sweden)

    Nancy Mariel Apóstolo

    2005-12-01

    Full Text Available Veintiún especies (doce Dicotyledoneae y nueve Monocotyledoneae pertenecientes a la vegetación costera del río Salado (noroeste de la provincia de Buenos Aires, Argentina fueron estudiadas con el fin de determinar las características anatómicas relacionadas a estrategias adaptativas al medio. Dichas especies pertenecen a los humedales de la cuenca del Salado y, por lo tanto, están afectadas por inundación, sequía temporaria y alta salinidad en agua y suelo. Caracteres anatómicos típicos de las especies que crecen en humedales combinados con características xeromórficas actuarían como estrategia adaptativa para aclimatarse en dicho medio. Los representantes de Poaceae y Cyperacae y algunos de Asteraceae tienen aerénquima en raíz y tallo. El 50% de las especies estudiadas muestran estructura Kranz. Escasas especies de Dicotyledoneae (Aizoaceae y Asteraceae muestran pelos de indumento. El tejido acuífero y los mucílagos son evidentes en especies de Aizoaceae, Chenopodiaceae, Malvaceae y Asteraceae. Ceras epicuticulares están presentes en mayor o menor grado en todas las especies analizadas. El 40% de las especies tienen glándulas de sal, principalmente las Poaceae. Cristales de oxalato de calcio y magnesio en diversas formas se observan en la mayoría de la Dicotyledoneae, no presentándose en Monocotyledoneae. Estas características anatómicas indican la capacidad de las especies para sobrevivir a condiciones extremas del medio en la vegetación costera del río Salado.In order to determine the anatomical features acting as adaptive strategies to the environment, 21 species were studied (12 Dicotyledoneae and nine Monocotyledoneae belonging to the coastal vegetation of the Salado river. These species are included in wetlands of Salado River Basin and are affected by flooding, drought and high salinity in water and soil. Typical anatomical features of wetland plants combined with xeromorphic characters could act as adaptive

  4. The liaohe river downstream wetland vegetation protection and research%辽河下游湿地植被的保护研究

    Institute of Scientific and Technical Information of China (English)

    王冬梅; 陈胜利

    2015-01-01

    辽河下游湿地是我国的重要湿地之一,通过对湿地植物芦苇进行室内、室外实验区的实验研究,总结出芦苇生长所需的最佳环境及水分含盐度. 提出在芦苇生长管理中,应根据芦苇需水规律,实行灌排结合的技术措施,既保证芦苇对水分的需求,又能够合理调节土壤通气状况,增加土壤通透性,促进土壤养分有效分解释放及芦苇根系发育和芦苇的生长,使湿地植物芦苇有一个良好的生长环境.%Liaohe River downstream wetlands is one of the important wetlands in our country, there is the world's largest coastal reed swamp wetland, this paper is based on the reed wetland plants for indoor and outdoor experimental area of experimental research, summed up the reeds grow the best environment and water salinity. Put forward in the reed growth management, should according to the laws of the reed water requirement, the irrigation and drainage combined with technical measures, which guarantee the reed demand for water, and can properly regulate soil aeration condition and increase soil permeability and promote soil nutrient release effective decomposition, promote the growth of reed root development and reed, the reed wetland plants have a good growth environment.

  5. Linking Weathering, Rock Moisture Dynamics, Geochemistry, Runoff, Vegetation and Atmospheric Processes through the Critical Zone: Graduate Student led Research at the Eel River Critical Zone Observatory

    Science.gov (United States)

    Dietrich, W. E.

    2014-12-01

    In the Eel River Critical Zone Observatory lies Rivendell, a heavily-instrumented steep forested hillslope underlain by nearly vertically dipping argillite interbedded with sandstone. Under this convex hillslope lies "Zb", the transition to fresh bedrock, which varies from less than 6 m below the surface near the channel to 20 m at the divide. Rempe and Dietrich (2014, PNAS) show that the Zb profile can be predicted from the assumption that weathering occurs when drainage is induced in the uplifting fresh bedrock under hillslopes by lateral head gradients driven by channel incision at the hillslope boundary. Infiltrating winter precipitation is impeded at the lower conductivity boundary at Zb, generating perched groundwater that dynamically pulses water laterally to the channel, controlling stream runoff. Below the soil and above the water table lies an unsaturated zone through which all recharge to the perched groundwater (and thus all runoff to channels) occurs. It is this zone and the waters in them that profoundly affect critical zone processes. In our seasonally dry environment, the first rains penetrate past the soil and moisten the underlying weathered bedrock (Salve et al., 2012, WRR). It takes about 200 to 400 mm of cumulative rain, however, before the underlying groundwater rises significantly. Oshun et al (in review) show that by this cumulative rainfall the average of the wide-ranging isotopic signature of rain reaches a nearly constant average annual value. Consequently, the recharging perched groundwater shows only minor temporal isotopic variation. Kim et al, (2014, GCA) find that the winter high-flow groundwater chemistry is controlled by relatively fast-reacting cation exchange processes, likely occurring in transit in the unsaturated zone. Oshun also demonstrates that the Douglas fir rely on this rock moisture as a water source, while the broadleaf trees (oaks and madrone) use mostly soil moisture. Link et al (2014 WRR) show that Doug fir declines

  6. General Vegetation

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This file contains vector digital data for vegetation groupings in New Mexico at a 1:1,000,000 scale. The source software was ARC/INFO 5.0.1 and the conversion...

  7. THE HOLOCENE FLORA AND VEGETATION OF THE NORTHERN RUSSIAN PLAIN (THE VYCHEGDA RIVER BASIN)%俄罗斯北部平原(VYCHEGDA河盆地)全新世植物群和植被

    Institute of Scientific and Technical Information of China (English)

    O.K.Borisova

    2002-01-01

    A section of floodplain deposits of the Vychegda River near the Baika village (61°16'N, 46°44'E) was studiedpalynologically. The site is located in the middle taiga zone, near the boundary of the European spruce forest and sub-Urals-Siberian spruce-fur-Siberian pine forest. The river basin is densely forested (up to 98%). According to the radiocarbon dating,the sedimentation took place during the major part of the Holocene, since app. 9000 yrs B.P.Reconstruction of the vegetation and climatic changes in the region during the Holocene is based on the composition offossil floras (Grichuk, 1969). Geographical analysis of modem spatial distribution of all the plant taxa of certain fossil floraallows to locate the closest modern floristic analogue to the past vegetation. By identifying the region where all the species ofplants grow at the present time it is possible to determine the closest modem landscape and climatic analogue to the pastenvironment under consideration. The present-day features of plant communities and main climatic indices of such a region-analogue should be close to if not identical with those existed at the site in the past.Pollen assemblages were dominated by spruce, pine and birch pollen through the whole sediment sequence, but neverthe-less substantial changes took place both in the composition of flora and vegetation. Participation of the warm-temperatedeciduous trees (linden, elm, and oak) in the forest communities varied through time and reached its maximum in the warmestinterval of the Holocene, correspondent to the middle and late Atlantic (6000-4500 yrs B.P.). These changes are reflected by"migration" of modern floristic analogue regions over the Russian Plain beginning from the Middle and Southern Urals as farwest as the Sukhona River Basin, and back to the site under study at the downstream end of the Vychegda River. Quantitativereconstructions of the main climatic indexes, based on the paleofloristic method, show that in the Atlantic

  8. componente vegetal

    Directory of Open Access Journals (Sweden)

    Fabio Moscovich

    2005-01-01

    Full Text Available In order to determine environmental impact, indicators based on vegetation characteristics that would generate the forestry monoculture with the adjacent native forest, 32 sample unit were installed in an area of LIPSIA private enterprise, Esperanza Department, Misiones with those characteristics. The plots of 100 m2 were distributed systematically every 25 meters. The vegetation was divided in stratum: superior (DBH ≥ 10 cm, middle (1,6 cm ≤ DBH > 10 cm and inferior (DBH< cm. There were installed 10 plots in a logged native forest, 10 plots in a 18 years old Pinus elliottii Engelm. with approximately 400 trees/ha., 6 plots in a 10 – 25 years old Araucaria angustifolia (Bertd. Kuntze limiting area with approximately 900 trees/ha., and 6 plots located in this plantation. In the studied area were identified 150 vegetation species. In the inferior stratum there were found differences as function of various floristic diversity indexes. In all the cases the native forest showed larger diversity than plantations, followed by Pinus elliottii, Araucaria plantation and Araucaria limiting area. All the studied forest fitted to a logarithmical series of species distributions, that would indicate the incidence of a environmental factor in this distribution.

  9. Sensitivity Analysis of a Riparian Vegetation Growth Model

    Directory of Open Access Journals (Sweden)

    Michael Nones

    2016-11-01

    Full Text Available The paper presents a sensitivity analysis of two main parameters used in a mathematic model able to evaluate the effects of changing hydrology on the growth of riparian vegetation along rivers and its effects on the cross-section width. Due to a lack of data in existing literature, in a past study the schematization proposed here was applied only to two large rivers, assuming steady conditions for the vegetational carrying capacity and coupling the vegetal model with a 1D description of the river morphology. In this paper, the limitation set by steady conditions is overcome, imposing the vegetational evolution dependent upon the initial plant population and the growth rate, which represents the potential growth of the overall vegetation along the watercourse. The sensitivity analysis shows that, regardless of the initial population density, the growth rate can be considered the main parameter defining the development of riparian vegetation, but it results site-specific effects, with significant differences for large and small rivers. Despite the numerous simplifications adopted and the small database analyzed, the comparison between measured and computed river widths shows a quite good capability of the model in representing the typical interactions between riparian vegetation and water flow occurring along watercourses. After a thorough calibration, the relatively simple structure of the code permits further developments and applications to a wide range of alluvial rivers.

  10. 雅砻江流域植被指数长时间序列变化分析%Analysis on vegetation index's long time series dynamics of Yalong River basin

    Institute of Scientific and Technical Information of China (English)

    田甜; 李绍才; 陈敏; 孙海龙

    2012-01-01

    Change in the vegetation cover of land directly incarnates and represents the influence of human activities.This paper analyzes the dynamics of vegetation cover with techniques of trend line analysis and correlation analysis and presents a case study of spatial and temporal variations of vegetation cover in the hydropower-developing Yalong River basin during the years 1982-2006.The results show that the annual maximal NDVI was reduced by 0.0004 every year and that the cover degree in the lower reach was better than that in the middle reach,while the latter was better than the upper reach.The cover in the middle and lower reaches took a decreasing trend over these years,which was probably caused by the hydropower construction activities and the climate change.An examination on the relationship of NDVI values versus 11 climatic factors for five counties reveals that the NDVI is strongly correlated with the mean values of pressure,temperature,maximum temperature and minimum temperature.The Pearson correlation coefficients of these factors are 0.881,0.879,0.867 and 0.877,respectively.%土地覆被的变化直接体现和反映了人类活动的影响程度。本文以雅砻江流域水电开发为例,采用趋势线分析法、相关分析法等方法综合研究了流域1982-2006年24年间的植被覆被时空动态变化过程。研究结果表明,年最大NDVI值递减0.0004/年,多年植被覆被度状况:下游〉中游〉上游,而通过趋势线分析植被覆盖度增减情况是:上游〉中游〉下游。中下游的植被覆盖度多年来呈现出递减趋势这可能与电站建设活动及气候变异有关。同时分析了5个县市NDVI值与11个气候因子之间的关系,结果表明NDVI与平均气压、平均气温、平均最高气温、平均最低气温都有很强的相关性,Pearson相关系数分别为0.881、0.879、0.867、0.877。

  11. STUDY OF THE FLOW THROUGH NON-SUBMERGED VEGETATION

    Institute of Scientific and Technical Information of China (English)

    NEHAL Laounia; YAN Zhong-min; XIA Ji-hong

    2005-01-01

    Vegetation is an important feature of many rivers. Vegetation along rivers produces high resistance to flow and, as a result, has a large impact on water levels in rivers and lakes. The effects of instream-unsubmerged vegetation (such as the reed-similar Kalmus) on flow resistance and velocity distributions is studied in the paper. Artificial vegetation is used in the experimental study to simulate the Acorus Calmus L. As shown in experimental tests the resistance depends strongly on vegetation density and the Manning resistance coefficient varies with the depth of flow. A simplified model based on concepts of drag is developed to evaluate the roughness coefficient (Manning's n) for non-submerged vegetation. In vegetated channels the overall flow resistance is influenced significantly by the distribution pattern of the vegetated beds. Within vegetation, vertical variation in velocity is different from that in the non-vegetated bed, which reflects the variation in vegetation density. Vertical turbulent transport of momentum is negligible as demonstrated by experiments.

  12. 黑河下游绿洲植被优势种生物量空间分布及蒸腾耗水估算%Biomass-based Transpiration Water Consumption of Dominant Species of Vegetation Estimation in the Oasis of Lower Reaches of Heihe River

    Institute of Scientific and Technical Information of China (English)

    张华; 张兰; 赵传燕; 彭守璋; 郑祥霖

    2014-01-01

    基于典型样点试验,建立了研究区植被优势种柽柳、胡杨与苦豆子地上生物量与其生态参数关系模型;利用高分辨率遥感影像Geoeye-1对植被优势种进行分类得到生态参数,实现了其地上部分生物量空间分布估算;最后利用生物量与蒸腾系数关系,估算植被优势种蒸腾耗水。结果显示:植被优势种总生物量为2.53×106t,河流距离对生物量影响显著。根据试验测得的植被优势种蒸腾系数估算出总蒸腾耗水量为10.89×108t,柽柳、胡杨与苦豆子所占比例分别为12.94%,82.93%与4.13%。%The research object of this study are the Tamarix ramosissima, Populus euphratica and Sophora which are the dominant species vegetation in lower reaches of Heihe River. Guided by the theories of Ecology Hydrology, Geobotany, Statistics theories and other disciplines, field investigation combined with remote sens-ing and spatial analysis methods were applied to study biomass and transpiration water consumption of domi-nant species of vegetation in study area. Firstly, biological characteristics of typical samples survey and bio-mass observation of dominant species of vegetation was made. The relational model of aboveground biomass and the ecological parameters (canopy area or coverage area) of dominant species of vegetation were construct-ed. Then, ecological parameters of dominant species of vegetation were obtained from high resolution satellite imagery Geoeye-1 which were classified by decision tree method to realize the spatial distribution estimation of aboveground biomass of dominant species of vegetation. Finally, the transpiration water consumption of dominant species of vegetation was estimated by the relationship between biomass and transpiration coeffi-cient. According to the studying results, the spatial distribution characteristics of aboveground biomass and transpiration water consumption of 0-2 km, 2-5 km, 5-10 km and 10-15 km river buffer

  13. Identification of Forest Vegetation Using Vegetation Indices

    Institute of Scientific and Technical Information of China (English)

    Yuan Jinguo; Wang Wei

    2004-01-01

    Spectral feature of forest vegetation with remote sensing techniques is the research topic all over the world, because forest plays an important role in human beings' living environment. Research on vegetation classification with vegetation index is still very little recently. This paper proposes a method of identifying forest types based on vegetation indices,because the contrast of absorbing red waveband with reflecting near-infrared waveband strongly for different vegetation types is recognized as the theoretic basis of vegetation analysis with remote sensing. Vegetation index is highly related to leaf area index, absorbed photosynthetically active radiation and vegetation cover. Vegetation index reflects photosynthesis intensity of plants and manifests different forest types. According to reflectance data of forest canopy and soil line equation NIR=1.506R+0.0076 in Jingyuetan, Changchun of China, many vegetation indices are calculated and analyzed. The result shows that the relationships between vegetation indices and forest types are that perpendicular vegetation index (PVI) identifies broadleaf forest and coniferous forest the most easily;the next is transformed soil-adjusted vegetation index(TSVI) and modified soil-adjusted vegetation index(MSVI), but their calculation is complex. Ratio vegetation index (RVT) values of different coniferous forest vary obviously, so RVI can classify conifers.Therefore, the combination of PVI and RVI is evaluated to classify different vegetation types.

  14. Vegetation Map and Vegetation Monographs of China

    Institute of Scientific and Technical Information of China (English)

    GUO Ke

    2010-01-01

    @@ Vegetation Map of China As the most significant component of an ecosystem,vegetation plays the most important role in maintaining biodiversity and providing the necessary resources for human beings.A vegetation map shows the major vegetation types of a region and their geographic distribution patterns.

  15. Spatial Heterogeneity of Vegetation in China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The spatial heterogeneity and ecological characteristics of 74 vegetation types and the lack of vegetation type within the 9.6 million km2 of Chinese territory were studied using data from the China vegetation map. The analysis used 877 large quadrats 10 mm×10 mm (actual size 100 km×100 km), which covered about 8.77 million km2. Each large-quadrat was divided into four small 5 mm×5 mm quadrats (actual size 50 km×50 km). The frequency of occurrence of all vegetation types was recorded in each small quadrat.The survey using the Shiyomi method of vegetation analysis based on the beta-binomial distribution was adopted to describe the frequency of occurrence and spatial heterogeneity for each kind of vegetation. The weighted average heterogeneity of all the vegetation types in the landscape provides a measure of the landscape level heterogeneity which describes the spatial intricacy of the existing vegetation composition.The maximum spatial vegetation heterogeneity was 0.8620 in the frigid-temperate coniferous forest of Larix(V1), which dominates cold moist northeast China. The minimum spatial heterogeneity with a low occurrence was the Caragana tibetica in the gravel desert in the western Yellow River Hetao area. The minimum occurrence with a low spatial heterogeneity was the Monsoon rainforest on rock in Guangxi and Yunnan Provinces. The vegetation types on the Qing-Zang Plateau were found to be representative of Chinese vegetation because of the very high occurrence and spatial heterogeneity of these vegetation types. The weighted average of the heterogeneity was 0.677, while the vegetation diversity index was 3.29.

  16. 澜沧江上游不同植被类型土壤微生物特征研究%The Study on Soil Microbial Characteristic under Different Types of Vegetation in Upstream of Lancang River

    Institute of Scientific and Technical Information of China (English)

    张仕艳; 原海红; 陆梅; 杨国仲; 向仕敏

    2011-01-01

    采用野外调查采样及室内实验分析的方法,选取原生植被旱冬瓜林地作为对照,对澜沧江上游山区不同植被类型云南松林、桉树纯林、生态混交林(桤木+圣诞树)土壤细菌、真菌、放线菌3大类微生物的数量及总量进行研究,结果表明:3大类微生物分布均表现为A层大于B层。不同植被类型土壤细菌和真菌数量变化趋势均为旱冬瓜林〉生态混交林〉桉树林〉云南松林,且A、B层消长趋势一致;不同植被类型A层土壤放线菌数量变化趋势为云南松林〉桉树林〉生态混交林〉旱冬瓜林,B层土壤放线菌数量变化趋势则为生态混交林〉云南松林〉桉树林〉旱冬瓜林;不同植%With the Alnus nepalensis forest as control,to investigate the quantity of soil microbe(bacteria,epiphyte and actinomyces) and microbial biomass of different vegetation types in upstream of Lancang River by the method of field sampling and laboratory analysis.The others vegetation types are Pinus yunnanensis,eucalyptus and eco-mixed forest(Alnus nepalensis+Acacia dealbata).The results indicated that the A layer of the quantity of bacteria,epiphyte and actinomyces were higher than the B layer.The order of the A layer the quantity of bacterial and epiphyte were Alnus nepalensis forest 〉eco-mixed forest〉eucalyptus〉Pinus yunnanensis.The B layer is same as the A layer.In the A layer,the order of the quantity of actinomyces was Pinus yunnanensis〉eucalyptus〉eco-mixed forest 〉Alnus nepalensis forest.In the B layer,the order of the quantity of actinomyces was eco-mixed forestPinus yunnanensiseucalyptusAlnus nepalensis forest.In the A layer,the order of soil microbial biomass is Alnus nepalensis fores eco-mixed forest〉eucalyptus〉Pinus yunnanensis.The order in B layer is same as that in A layer.

  17. Regional year-round sypply of vegetables in North Vietnam

    NARCIS (Netherlands)

    Everaarts, A.P.; Wijk, van M.S.; Pham Van Hoi,

    2008-01-01

    A discussion is presented about the patterns in the present year-round supply of vegetables to large cities in the Red River Delta in North Vietnam. Especially during the hot summer season, vegetables are supplied from Dalat in South Vietnam or from Kunming Province in China. Generally speaking, imp

  18. Incipient motion of sediment in presence of submerged flexible vegetation

    Institute of Scientific and Technical Information of China (English)

    Hao Wang; Hong-wu Tang; Han-qing Zhao; Xuan-yu Zhao; Sheng-qi Lu¨

    2015-01-01

    The presence of submerged vegetation on river beds can change the water flow structure and alter the state of sediment motion. In this study, the incipient motion of sediment in the presence of submerged flexible vegetation in open channels was investigated in a laboratory experiment. The vegetation was simulated with flexible rubber cylinders arranged in parallel arrays. The effect of the vegetation density, water depth, and sediment grain size on the incipient motion was investigated. The experimental results indicate that the incipient motion velocity of sediment increases as the vegetation density decreases and the water depth and sediment grain size increase. With flexible plants, the incipient motion velocity of sediment is lower than it is without vegetation, and is larger than it is with rigid vegetation. A general incipient motion velocity equation was derived, which can be applied to both flexible and rigid vegetation conditions.

  19. Classification of floodplain vegetation by data fusion of spectral (CASI) and LiDAR data

    NARCIS (Netherlands)

    Geerling, G.W.; Labrador-Garcia, M.; Clevers, J.G.P.W.; Ragas, A.M.J.; Smits, A.J.M.

    2007-01-01

    To safeguard the goals of flood protection and nature development, a river manager requires detailed and up-to-date information on vegetation structures in floodplains. In this study, remote-sensing data on the vegetation of a semi-natural floodplain along the river Waal in the Netherlands were gath

  20. Classification of floodplain vegetation by data-fusion of Spectral (CASI) and LiDAR data

    NARCIS (Netherlands)

    Geerling, G.W.; Labrador-Garcia, M.; Clevers, J.G.P.W.; Ragas, A.M.J.; Smits, A.J.M.

    2007-01-01

    To safeguard the goals of flood protection and nature development, a river manager requires detailed and up‐to‐date information on vegetation structures in floodplains. In this study, remote‐sensing data on the vegetation of a semi‐natural floodplain along the river Waal in the Netherlands were gath

  1. 石羊河流域海拔、植被覆盖与景观类型空间关系研究%Spatial relationship between elevation, vegetation cover and landscape types in Shiyang River Basin

    Institute of Scientific and Technical Information of China (English)

    魏伟; 石培基; 赵军; 王旭峰

    2012-01-01

    With the support of GIS technology, and taking the Landsat/TM images as the data source, 14 types of landscapes in Shiyang River basin were obtained in the study by employing the artificial interpretation method. A series of other data such as DEM, vegetation maps, and landscape maps were used. Besides, principal component a- nalysis as well as regression methods were adopted to analyze the landscape changes in different atitude and vegeta- tion cover, also the spatial relationship between NDVI, DEM and landscpe types were researched. The results showed that the landscape types were vertical distribution in terms of elevation, and the vertical-specific characteristics of natural elements were more obvious. In low-altitude area,landscape distribution was more single, and the relation- ship between NDVI and elevation were closely associated. Relatively, in high-altitude area, the distribution of land- scape was staggered. Besides, the distribution of landscape types has evident altitudinal regularity from Qilian mountains in south to desert region in north, and the distribution order is approximately as follows : glacier and snow - cold desert - water area - marsh land - grassland - woodland - farmland - residential area - overflow land - salinized land - bare soil - bare rock - sandy desert - gobi from valley to mountain top for the big verti- cal space of the height above the sea level. This shows that the influenced areas which are disturbed by human be-ings are in the low altitude. From advanced study,we find residential area is mainly distributed under 2 500 m, a- bout 84.5 % city and town residents live in the range of 1 200 - 3 000 m, but in the range of 3 000 and 4 000 m, residential area only occupies 16. 455%. In thealtitude of 4 500 m above, there is no residential distribution. Through further research ,we find the distribution boundaries and characteristics presented unbalanced. Hence the relaiontship among landscape types,NDVI and DEM were very

  2. Audubon vegetation monitoring

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document is the summary and the analysis of vegetative data for the Audubon Refuge from NPWRC. The data included measurements of vegetation density, vegetation...

  3. Lake Bathymetric Aquatic Vegetation

    Data.gov (United States)

    Minnesota Department of Natural Resources — Aquatic vegetation represented as polygon features, coded with vegetation type (emergent, submergent, etc.) and field survey date. Polygons were digitized from...

  4. 基于MODIS的雅鲁藏布江流域干旱动态监测及对植被胁迫作用的研究%RESEARCH ON DYNAMIC MONITORING OF DROUGHT AND THE IMPACT ON VEGETATION IN THE BRAHMAPUTRA RIVER BASIN BASED ON MODIS

    Institute of Scientific and Technical Information of China (English)

    郭兵; 陶和平; 姜琳; 孔博; 刘斌涛; 史展; 宋春风

    2013-01-01

    基于MODIS数据利用垂直干旱指数模型和重心模型分析了2011年4月~2012年4月的雅鲁藏布江流域干旱动态变化,并就干旱对植被的胁迫作用做了进一步探讨.研究发现:(1)干旱强度减弱区主要分布于雅鲁藏布江流域的中部,而干旱强度增强区则主要集中于该流域的上游及下游地区;(2)2012年4月份雅鲁藏布江流域的总体干旱强度相比2011年4月有所加重,轻度干旱、重度干旱区均有所增长,而湿润区则有一定减小.干旱强度加重较大的区域主要分布于拉萨河流域及>3 000~4 000 m、>4 000~5 000 m高度带;(3)雅鲁藏布江流域的NDVI与PDI的重心迁移具有很好的负相关性,说明其干旱动态变化对植被具有较明显的胁迫作用.%Based on MODIS,the study analyzes the dynamic change of drought intensity between April 2011 and April 2012 with the models of gravity center and the perpendicular drought index in the Brahmaputra river basin,then it takes a further explore of impact on the vegetation.The results show as follows.(1)The region of weakened drought intensity was mainly located in the middle reaches of the Brahmaputra River which included Shigatse City,Jiangzi County,Qushui County,Renbu county and Zhanang county,while zone of the aggravated drought intensity was mainly concentrated in the upstream and downstream of the Brahmaputra River such as Lunggar county,Zhongba county and Cuole county.(2) On the whole,the intensity of the drought in April 2012 had been aggravated than that in April 2011 in the Brahmaputra River Basin.Areas of mild drought,severe drought increased,however the areas of wet reduced.The regions of severely aggravated drought intensity were mainly distributed in the Lhasa River Basin and the belts of >3 000~4 000 m and >4 000~5 000 m such as Naqu county,Linzhou county and Mozhugongka county.(3)The transfer trajectory of gravity center indicated that:NDVI and PDI had a good negative

  5. Soil-vegetation-atmosphere transfer modeling

    Energy Technology Data Exchange (ETDEWEB)

    Ikonen, J.P.; Sucksdorff, Y. [Finnish Environment Agency, Helsinki (Finland)

    1996-12-31

    In this study the soil/vegetation/atmosphere-model based on the formulation of Deardorff was refined to hour basis and applied to a field in Vihti. The effect of model parameters on model results (energy fluxes, temperatures) was also studied as well as the effect of atmospheric conditions. The estimation of atmospheric conditions on the soil-vegetation system as well as an estimation of the effect of vegetation parameters on the atmospheric climate was estimated. Areal surface fluxes, temperatures and moistures were also modelled for some river basins in southern Finland. Land-use and soil parameterisation was developed to include properties and yearly variation of all vegetation and soil types. One classification was selected to describe the hydrothermal properties of the soils. Evapotranspiration was verified against the water balance method

  6. Vegetation line transects of Goose Pasture and Pool No. 1: Part of Wildlife Management Study – Project 2: Evaluating production of moist soil plants in the Mississippi River Flood Plain and their subsequent use by waterfowl

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Wildlife Management Study - Project No. 2 dated May 15, 1969 was developed to evaluate the production of moist soil food plants in the Mississippi River flood...

  7. Plant biomass in the Tanana River Basin, Alaska.

    Science.gov (United States)

    Bert R. Mead

    1995-01-01

    Vegetation biomass tables are presented for the Tanana River basin. Average biomass for each species of tree, shrub, grass, forb, lichen, and moss in the 13 forest and 30 nonforest vegetation types is shown. These data combined with area estimates for each vegetation type provide a tool for estimating habitat carrying capacity for many wildlife species. Tree biomass is...

  8. River engineering

    NARCIS (Netherlands)

    De Vries, M.

    1993-01-01

    One dimension models - basic eauations, analytical models, numberical models. One dimensional models -suspended load, roughness and resistance of river beds. Solving river problems - tools, flood mitigation, bank protection.

  9. 京杭运河淮安段不同植物护坡模式消风减噪及小气候效应%Effects of Pattern of Vegetative Protection of River Slopes on Wind, Noise and Micrometeorology Along the Huai'an Section of the Grand Canal

    Institute of Scientific and Technical Information of China (English)

    李冬林; 张小茜; 金雅琴; 许波

    2012-01-01

    对京杭运河淮安段5种植物护坡模式的消风减噪及小气候效应进行测定,结果表明,植物护坡对风速、噪声、光照强度、气温、相对湿度等均有明显调节作用.与无植物对照地相比,有芦苇(Phragmites australis)分布的近水区风速明显变小,噪声降低,随着苇群密度和宽度的增加,其削减效果加强.桃树(Prunus persica)+芦苇群落消风、遮光和增湿效应明显,并有一定经济收益,在京杭运河护坡设计中可进一步推广应用;水杉(Metasequoia glyptostroboides)+芦苇群落具有一定的降温和增湿作用,但减噪和遮光效果不好,可设计在地势低洼的河岸带,利于人们冬季休闲观光;梨树(Pyrus bretschneideri)+芦苇群落有明显的消风和减噪作用,但由于人为干扰等原因影响了群落小气候效应的发挥;狗牙根(Cynodon dactylon)草地+芦苇群落生态效应明显不足,在河岸带护坡设计中应尽量避免使用该模式.%Effects of five different patterns of vegetative protection of river slopes on wind, noise and micrometeoroiogy a-long the Huai'an Section of the Grand Canal were studied. Results show that the effects of vegetative protection regulating wind speed, noise level, sunlight intensity, air temperature and relative humidity were quite obvious. Compared with the control of vegetation-free slope, the slope with Phragmites australis had lower wind speed and noise level at the water side and the effects became stronger with the reed community growing wider and denser. The vegetative protection formed of Prunus persica + Phragmites australis was very effective in reducing wind speed, providing shade and increasing humidity, and what's more, in creating some economic profit, so that, it is a pattern worth further extrapolating along the Grand Canal. The vegetative protection composed of Metasequoia glyplostroboides + Phragmites australis had certain effect of reducing air temperature and increasing humidity

  10. Vegetation Dynamics and Associated Driving Forces in Eastern China during 1999–2008

    Directory of Open Access Journals (Sweden)

    Jian Peng

    2015-10-01

    Full Text Available Vegetation is one of the most important components of the terrestrial ecosystem and, thus, monitoring the spatial and temporal dynamics of vegetation has become the key to exploring the basic process of the terrestrial ecosystem. Vegetation change studies have focused on the relationship between climatic factors and vegetation dynamics. However, correlations among the climatic factors always disturb the results. In addition, the impact of anthropogenic activities on vegetation dynamics was indeterminate. Here, vegetation dynamics in 14 provinces in Eastern China over a 10-year period was quantified to determine the driving mechanisms relating to climate and anthropogenic factors using partial correlation analysis. The results showed that from 1999 to 2008, the vegetation density increased in the whole, with spatial variations. The vegetation improvement was concentrated in the Yangtze River Delta, with the vegetation degradation concentrated in the other developed areas, such as Beijing-Tianjin-Hebei Region and the Pearl River Delta. The annual NDVI changes were mainly driven by temperature in Northeast China and the Pearl River Delta, and by precipitation in the Bohai Rim; while in the Yangtze River Delta, the driving forces of temperature and precipitation almost equaled each other.  Furthermore, the impact of anthropogenic activities on vegetation dynamics had accumulative effects in the time series, and had a phase effect on the vegetation change trend.

  11. Spatial and temporal variation characteristics of vegetation cover fractal dimension in Dali River watershed based on GIS and RS%基于GIS与RS的大理河流域植被格局分形维数时空变化特征

    Institute of Scientific and Technical Information of China (English)

    李斌斌; 李占斌; 李鹏

    2015-01-01

    for each other. We computerize the difference of NDVI values between each pixel point and the center pixel point in each cell. We calculate NDVI increment value of the watershed points at a certain spatial scale by the moving window statistical method, then computerize mathematics expectations of measure collection, which is composed of all NDVI incremental values. To study the characteristics of fractal dimension of the vegetation cover and its variation at different scales, it is divided into 4 scales according to the area of the basin, with 5 phases per level. The first level is the entire Dali River basin with an area of 3 906 km2, approximately 5 million times of pixel size (30 m × 30 m). At the second stage, Dali River basin will be divided into 3 parts i.e. upstream, midstream and downstream, with an average area of approximately 1 000 km2, approximately 1 million times of pixel size (30 m × 30 m). At the third stage, it will be divided into 14 small basins of Dali River, with an area of 179.4-392.5 km2, about 200 thousand times of pixel size (30 m × 30 m). At the fourth stage, it will be divided into 53 small basins of Dali River (No.1 to 53), with an area of 21.9-108.9 km2, about 40 thousand times of pixel size (30 m × 30 m). Firstly, on the basis of information source from 5 issues of TM/ETM images from 1990 to 2006, the image data are processed, the vegetation information at basin stage is extracted by the platform of geographic information system (GIS), and then watershed DVM is established. FBM (fractional brownian motion) fractal dimension for watershed vegetation cover is between 2.7311 and 2.8499. By calculation and analysis, vegetation cover FBM fractal dimension is increasing from upstream to downstream, so vegetation distribution is more uniform from upstream to downstream. Vegetation cover fractal dimension is increasing with the watershed area. Through analyzing spatial and temporal variation of each sub-watershed at all levels, it presents

  12. Landscape gradients and patchiness in riparian vegetation on a Middle Pennsylvanian braided-river plain prone to flood disturbance (Nýrany Member, Central and Western Bohemian Basin, Czech Republic)

    DEFF Research Database (Denmark)

    Bashforth, Arden Roy; Drábková, Jana; Opluštil, Stanislav;

    2011-01-01

    to avulsion and flooding. Taphonomic observations and multivariate analysis of 41 quadrats containing mostly (par)autochthonous megafloral assemblages reveal that riparian vegetation comprised a collage of monospecific to low-diversity communities, with patchiness prevalent at local and regional scales...

  13. Monitoring vegetation growth and morphodynamic effects after stream restoration

    Science.gov (United States)

    Vargas-Luna, Andrés; Crosato, Alessandra; Anders, Niels; Hoitink, Ton; Keesstra, Saskia; Uijttewaal, Wim

    2016-04-01

    Vegetation processes are widely recognized as a key component on the ecological and morphological development of river channels. Moreover, plants reduce flow velocities and bed-shear stresses by increasing the local hydraulic roughness and thus increasing water levels. Therefore, monitoring the vegetation development is an important activity in river management not only for protecting ecological services, but also in flood risk reduction; especially in times of a changing climate. This paper presents the analysis the effects of riparian vegetation growth on the morphology of a lowland restored stream located in The Netherlands, the Lunterse beek. An Unmanned Aerial Vehicle (UAV) was used to obtain aerial imagery at different time steps which was the basis for generating land cover maps with semi-automated image classification. In addition hydrological series and multi-temporal high-resolution bathymetric data allowed analysing river bed morphology and the relevance of seasonality. The UAV campaigns were found a crucial step to ease the vegetation mapping and monitoring. The morphological change observed in this stream, represented by the channel-width adjustment and the cross sectional evolution, is slowed down once vegetation is stablished on the stream. Results of this work show that the vegetation root system assert a strong control on soil stabilization, even during the winter season when the plants biomass is highly reduced. Seasonal variations in plant development appear important only during the first stages of establishment, when vegetation has a low density and, more importantly, a root system that is not fully developed yet.

  14. The Weird Vegetable Price

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The Chinese Government faces the task of stabilizing vegetable prices to avoid steep increases and dips Fluctuations of vegetable prices in China have recently caused near panic in the domestic market.Purchase prices for farm produce are decreasing dramatically

  15. Procedures for Sampling Vegetation

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report outlines vegetation sampling procedures used on various refuges in Region 3. The importance of sampling the response of marsh vegetation to management...

  16. Total Vegetation 2002

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These are polygons that contain vegetated pixels in the May, 2002 imagery from aerial overflight of the Grand Canyon. Vegetation was mapped between stage elevations...

  17. 天山北坡玛纳斯河流域晚冰期以来植被垂直带推移%Shifting of vertical vegetation zones in Manas River drainage on northern slope of Tianshan Mountains since the Late Glacier

    Institute of Scientific and Technical Information of China (English)

    纪中奎; 刘鸿雁

    2009-01-01

    The statistical relationships between climate indexes(moisture index and warmth index)and typical pollen taxa were established with linear regression method on the Manas River drainage on the northern slope of the Tianshan Mountains.Climate and vegetation developments in this region were reconstructed based on the different pollen taxa content of a previously published sediment sequence from the Manas Lake, a desiccated end lake of the Manas River, as well as modern climate, vegetation and landform relationships.Since 13000 a BP, the palaeoclimate change in this area has experienced several important stages: warm-dry, cold-moist, warm-dry, cold-moist, warm-dry, cold-moist and warm-dry, in correspondance with the climate change, ancient vertical vegetation change around the area has experienced a series of succession processes: desert, desert steppe(to develop lowland meadow and stepped locally), extreme arid desert, desert steppe, desert, desert steppe, desert.When the climate in the Manas River drainage changed from warm-dry to cold-moist, all vegetation boundaries in the area moved downward, hence the area of desert and forest was enlarged and the lower limit of conifer may get to current steppe.When the palaeoclimate changed from cold-moist to warm-dry, all vegetation boundaries moved upward, the area of desert was enlarged, while the area of steppe and forest was decreased, and the lower limit of conifer may get to current alpine and sub alpine meadow.%建立了反映天山北坡玛纳斯河流域典型花粉类型与气候指标(湿润指数和温暖指数)的统计函数.基于前人研究得出的玛纳斯湖沉积剖面中不同花粉的百分含量复原了晚冰期以来玛纳斯河流域古气候的变化,并基于山地植被-气候-地形关系推断了玛纳斯河流域的植被演变过程.研究结果表明:该区晚冰期以来经历了暖干-冷湿-暖干-偏冷偏湿-暖干-冷湿-暖干的气候变化过程,植被垂直带基带相应为荒漠-

  18. Monitoring of riparian vegetation response to flood disturbances using terrestrial photography

    Directory of Open Access Journals (Sweden)

    K. Džubáková

    2014-03-01

    Full Text Available The distribution of riparian vegetation on river floodplains is strongly impacted by floods. In this study we use a new setup with high resolution ground-based cameras in an Alpine gravel bed braided river to quantify the immediate response of riparian vegetation to flood disturbance with the use of vegetation indices. Five largest floods with return periods between 1.4 and 20.1 years in the period 2008–2011 in the Maggia River were used to evaluate patterns of vegetation response in three distinct floodplain units (main bar, secondary bar, transitional zone and to compare seven vegetation indices. The results show both negative (damage and positive (enhancement response of vegetation in a short period following floods, with a selective impact based on the hydrogeomorphological setting and the intensity of the flood forcing. The spatial distribution of vegetation damage provides a coherent picture of floodplain response in the three floodplain units with different flood stress. We show that the tested vegetation indices generally agree on the direction of predicted change and its spatial distribution. The average disagreement between indices was in the range 14.4–24.9% despite the complex environment, i.e. highly variable surface wetness, high gravel reflectance, extensive water–soil–vegetation contact zones. We conclude that immediate vegetation response to flood disturbance may be effectively monitored by terrestrial photography with potential for long-term assessment in river management and restoration projects.

  19. Dutch Vegetation Database (LVD)

    NARCIS (Netherlands)

    Hennekens, S.M.

    2011-01-01

    The Dutch Vegetation Database (LVD) hosts information on all plant communities in the Netherlands. This substantial archive consists of over 600.000 recent and historic vegetation descriptions. The data provide information on more than 85 years of vegetation recording in various habitats covering te

  20. Características sedimentares fluviais associadas ao grau de reservação da mata Ciliar - Rio Urumajó, Nordeste Paraense Fluvial sedimentology associated with the degree of preservation of the riparian vegetation, Urumajó River, PA / Brazil

    Directory of Open Access Journals (Sweden)

    Roney Nonato Reis de Brito

    2009-03-01

    Full Text Available Os rios são os agentes mais importantes no transporte dos sedimentos para as áreas mais baixas dos continentes e para o mar. Além dos efeitos diretos do clima local, a cobertura vegetal atua no controle da descarga e no suprimento de sedimentos. Sendo assim, o presente trabalho enfoca o padrão de distribuição granulométrica do rio Urumajó (nordeste paraense em relação ao estado de preservação da mata ciliar. Cinco estações (A-E foram estabelecidas de forma a registrar um transecto da nascente à foz do rio. Nessas estações, procedeu-se com a caracterização da mata ciliar, bem como do seu grau de preservação. Além disto, elaborou-se um perfil transversal ao canal para cada estação, com coleta de cinco amostras de sedimentos em cada perfil. Estes foram submetidos à análise granulométrica, que resultou na obtenção de valores da média, mediana, seleção, assimetria e curtose. Com os resultados foi possível reconhecer as características sedimentares normais do rio, onde areia média é a principal classe granulométrica transportada. Foram observadas nas estações A e C a clara tendência das amostras serem moderadamente bem selecionadas e aproximadamente simétricas, com dominância absoluta de areia média, o que está diretamente relacionado ao seu bom estado de preservação. Significativas variações granulométricas nas estações B, D e E foram associadas com o processo erosivo das margens do rio, conseqüência da degradação da mata ciliar. Além disso, foi constatada a influência das correntes de maré na sedimentologia da estação E, subsidiando também a delimitação do ambiente estuarino que se encontra associado ao canal fluvial.Rivers are the main ways of sediment transport from inland to the coastal zone and oceans. Despite direct influence of climate, the vegetation coverage plays a central role in liquid and solid fluvial discharge. In this context, the present work aimed to study the fluvial

  1. Ecomorphodynamic approaches to river anabranching patterns

    Science.gov (United States)

    Crouzy, Benoît; Bärenbold, Fabian; D'Odorico, Paolo; Perona, Paolo

    2016-07-01

    We investigate the influence of vegetation on river morphological instabilities using an analytical framework. We first discuss the important role of the hydrological (flooding frequency) and biological (vegetation development rate) timescales. As long as the changes in riverbed morphology and vegetation over an interval comprising one flood and one low-flow period are small, we show that it is possible to simplify the description of a vegetated river with non-constant discharge. We propose physically-based and effective (neural) models for the feedback between vegetation and morphodynamics. Physically-based approaches use equations of morphodynamics extended to account for the interplay between flow, sediment and vegetation dynamics. While their foundation is solid, a physically-based description is only feasible for simple vegetation cover (grass to shrubs). For complex vegetated obstacles we present as an alternative effective approaches, explicitly including interactions (local and non-local) between obstacles. We focus on the role of vegetation in the emergence of ridge patterns observed in the presence of an ephemeral flow and correspondingly derive a set of conditions for patterns.

  2. Dynamically Monitoring Vegetation Cover by Remote Sensing in the Typical Salinization Region of Xinjiang: A Case Study in Delta Oasis of Weigan and Kuqa Rivers%新疆典型盐渍区植被覆盖度遥感动态监测——以渭干河-库车河三角洲绿洲为例

    Institute of Scientific and Technical Information of China (English)

    张飞; 塔西甫拉提·特依拜; 丁建丽; 何祺胜; 田源; 买买提·沙吾提; 王宏; 桂东伟

    2011-01-01

    Vegetation coverage, as an important part of the ecosystem, is closely related to the global climate and long-term economic benefits of the country. Meanwhile, vegetation coverage is an important parameter for the description and assessment of landscape or ecosystem. In the field remote sensing, application of vegetation index to describe vegetation coverage percentage is widely accepted and applied. In this paper, we took the delta oasis of Weigan and Kuqa rivers as research object. This study was based on the TM/ETM + images of 1989, 2001 and 2006, and applied the ENVI, ArcGIS software as technology methods. The vegetation index of VBSI was used to estimate the model of vegetation coverage according to the dimidiate pixel principle, and the estimation precision was later approved to be up to 83. 52%. Further, we produced the vegetation coverage graduation map of the delta oasis of Weigan and Kuqa rivers, and analyzed and appraised changes in its structure. The results revealed a pattern of spatial change in the vegetation coverage of the study area. Forest, grassland and farmland were three main land use types in medium-high and high coverage and played an important role in keeping vegetation cover. Forest area determined the changes of coverage area, while the other two land use types were definitely able to affect direction of the changes. Since forest, grassland and farmland played an important part in keeping regional vegetation coverage, it should be planned to continually plant trees, maintain grassland, protect farmland and control unused land in a long-term program. Finally, variation of vegetation environment quality from 1989 to 2006 was evaluated according to distribution of quantity and space condition rendered by plant cover digital image. By comparing plant cover grade images of the three periods with local statistics materials, this paper pointed out that the development of Wei-Ku oasis soil salinization was controlled by two important reasons

  3. Vegetation Description, Rare Plant Inventory, and Vegetation Monitoring for Craig Mountain, Idaho.

    Energy Technology Data Exchange (ETDEWEB)

    Mancuso, Michael; Moseley, Robert

    1994-12-01

    The Craig Mountain Wildlife Mitigation Area was purchased by Bonneville Power Administration (BPA) as partial mitigation for wildlife losses incurred with the inundation of Dworshak Reservoir on the North Fork Clearwater River. Upon completion of the National Environmental Protection Act (NEPA) process, it is proposed that title to mitigation lands will be given to the Idaho Department of Fish and Game (IDFG). Craig Mountain is located at the northern end of the Hells Canyon Ecosystem. It encompasses the plateau and steep canyon slopes extending from the confluence of the Snake and Salmon rivers, northward to near Waha, south of Lewiston, Idaho. The forested summit of Craig Mountain is characterized by gently rolling terrain. The highlands dramatically break into the canyons of the Snake and Salmon rivers at approximately the 4,700 foot contour. The highly dissected canyons are dominated by grassland slopes containing a mosaic of shrubfield, riparian, and woodland habitats. During the 1993 and 1994 field seasons, wildlife, habitat/vegetation, timber, and other resources were systematically inventoried at Craig Mountain to provide Fish and Game managers with information needed to draft an ecologically-based management plan. The results of the habitat/vegetation portion of the inventory are contained in this report. The responsibilities for the Craig Mountain project included: (1) vegetation data collection, and vegetation classification, to help produce a GIS-generated Craig Mountain vegetation map, (2) to determine the distribution and abundance of rare plants populations and make recommendations concerning their management, and (3) to establish a vegetation monitoring program to evaluate the effects of Fish and Game management actions, and to assess progress towards meeting habitat mitigation goals.

  4. Contested Rivers

    DEFF Research Database (Denmark)

    Gorm Hansen, Louise Lyngfeldt

    explores translocal connections through ethnographic fieldwork at a global water conference and preliminary fieldwork at chosen locations on China's Nu River. The Nu River is one of the last undammed rivers in Asia and runs through China close to the Chinese-Burmese border, then flows into the Andaman Sea...

  5. 基于S-W模型的韩江流域潜在蒸散发的气候和植被敏感性%Sensitivity of the potential evapotranspiration to climate and vegetation in Hanjiang River basin based on S-W Model

    Institute of Scientific and Technical Information of China (English)

    刘远; 周买春; 陈芷菁; 李绍文

    2013-01-01

    spatial and temporal variation of vegetation leaf area index (LAI) was derived from the composite AVHRR NDVI using the SiB2 method. The long-term meteorological dataset at 752 meteorological stations in China was used to provide the required meteorological data. Using the meteorological data from meteorological stations and the monthly composite AVHRR NDVI data from NASA GIMMS during the period of 2000-2006, PET over Hanjiang River basin was estimated by S-W model. It showed that the PET was not only affected by climate, but also changed with vegetation types and the growth of vegetation. PET was very sensitive to vegetation types. The calculated PET of different vegetation in the similar climate condition is quite different. The annual mean PET of evergreen needle leaf forests, croplands and woods savannas was 1136.6, 965.1 and 563.2 mm/a, respectively. The maximum value was twice as the minimum value. The sensitivity of the PET to meteorological factors was analyzed. It showed that the sensitivity of the PET to climate was quite different for different vegetation covers. PET of evergreen needle leaf forests is the most sensitive to vapour pressure. Its sensitivity coefficient was much larger than that of air temperature and solar radiation. The sensitivity of wind speed can be ignored. PET of croplands was sensitive to air temperature, solar radiation and vapour pressure while it was not so sensitivity to wind speed. Among all the meteorological factors, the PET of croplands was the most sensitive to air temperature. PET of woods savannas was also the most sensitive to air temperature, and was also sensitive to vapour pressure, wind speed and solar radiation. Their sensitivity coefficients were very close to each other. The sensitivity of the PET to vegetation LAI was then analyzed. It showed that PET of all vegetation covers was sensitive to LAI, but the sensitivity coefficients were smaller than that of the meteorological factors (except for wind speed). The

  6. Potential plant species distribution in the Yellow River Delta under the influence of groundwater level and soil salinity

    NARCIS (Netherlands)

    Fan Xiaomei,; Pedroli, B.; Liu Gaohuan,; Liu Hongguang,; Song Chuangye,; Shu Longcang,

    2011-01-01

    This article describes a multidisciplinary approach to assessing potential vegetation types. The relation between vegetation distribution as derived from field survey and habitat characteristics in the Yellow River Delta (YRD) was analyzed using detrended canonical correspondence analysis (DCCA). Th

  7. Potential plant species distribution in the Yellow River Delta under the influence of groundwater level and soil salinity

    NARCIS (Netherlands)

    Fan Xiaomei,; Pedroli, B.; Liu Gaohuan,; Liu Hongguang,; Song Chuangye,; Shu Longcang,

    2011-01-01

    This article describes a multidisciplinary approach to assessing potential vegetation types. The relation between vegetation distribution as derived from field survey and habitat characteristics in the Yellow River Delta (YRD) was analyzed using detrended canonical correspondence analysis (DCCA).

  8. Soil TPH concentration estimation using vegetation indices in an oil polluted area of eastern China

    National Research Council Canada - National Science Library

    Zhu, Linhai; Zhao, Xuechun; Lai, Liming; Wang, Jianjian; Jiang, Lianhe; Ding, Jinzhi; Liu, Nanxi; Yu, Yunjiang; Li, Junsheng; Xiao, Nengwen; Zheng, Yuanrun; Rimmington, Glyn M

    2013-01-01

    ... (Phragmites australis) around oil wells that have been producing oil for approximately 10 years in the Yellow River Delta, eastern China to evaluate the potential of vegetation indices and red edge parameters to estimate soil oil pollution...

  9. A brief account of coast vegetation near Port Elizabeth

    Directory of Open Access Journals (Sweden)

    H. C. Taylor

    1981-12-01

    Full Text Available The environment and vegetation of an area of coast north-east of Port Elizabeth, South Africa, are briefly described. Five major vegetation categories are recognized. These are: 1.  Scaevola thunbergii Pioneer Vegetation of  littoral dunes and  Ficinia lateralis Sedgeland of calcrete gravel; 2.  Olea exasperata Bush,  Pterocelastrus tricuspidatus Bushclumps and Dune Woodland; 3. Sundays River Scrub; 4. Fynbos of calcrete areas; and 5.  Themeda triandra Grassland. Invasion of the area by Acacia cyclops (Australian W'attle is described. A recommendation for the conservation of the area as a nature reserve is made.

  10. Technology Drives Vegetable Industry

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    @@ Arobot for vegetable planting is able to examine growing conditions, detect disease of the vegetables and pick up the ripe ones through identifying the color; a tomato tree is able to produce up to 3,000kgs of tomatoes; sweet potatoes are growing in the air; fish and vegeta-bles are living together harmoniously...Viewing these, you may doubt that you were in a fancy world.Actually, you are here at the 12th China (Shouguang) International Vegetable Sci-tech Fair.

  11. Theory, methods and tools for determining environmental flows for riparian vegetation: Riparian vegetation-flow response guilds

    Science.gov (United States)

    Merritt, D.M.; Scott, M.L.; Leroy, Poff N.; Auble, G.T.; Lytle, D.A.

    2010-01-01

    Riparian vegetation composition, structure and abundance are governed to a large degree by river flow regime and flow-mediated fluvial processes. Streamflow regime exerts selective pressures on riparian vegetation, resulting in adaptations (trait syndromes) to specific flow attributes. Widespread modification of flow regimes by humans has resulted in extensive alteration of riparian vegetation communities. Some of the negative effects of altered flow regimes on vegetation may be reversed by restoring components of the natural flow regime. 2. Models have been developed that quantitatively relate components of the flow regime to attributes of riparian vegetation at the individual, population and community levels. Predictive models range from simple statistical relationships, to more complex stochastic matrix population models and dynamic simulation models. Of the dozens of predictive models reviewed here, most treat one or a few species, have many simplifying assumptions such as stable channel form, and do not specify the time-scale of response. In many cases, these models are very effective in developing alternative streamflow management plans for specific river reaches or segments but are not directly transferable to other rivers or other regions. 3. A primary goal in riparian ecology is to develop general frameworks for prediction of vegetation response to changing environmental conditions. The development of riparian vegetation-flow response guilds offers a framework for transferring information from rivers where flow standards have been developed to maintain desirable vegetation attributes, to rivers with little or no existing information. 4. We propose to organise riparian plants into non-phylogenetic groupings of species with shared traits that are related to components of hydrologic regime: life history, reproductive strategy, morphology, adaptations to fluvial disturbance and adaptations to water availability. Plants from any river or region may be grouped

  12. Wyoming big sagebrush associations of eastern Oregon; vegetation attributes

    Science.gov (United States)

    This report provides a synopsis of several vegetative characteristics for the Wyoming big sagebrush complex in eastern Oregon covering the High Desert , Snake River, and Owyhee Ecological Provinces in Harney, Lake, and Malheur Counties. The complex has been grouped into six associations defined by t...

  13. River-Based Experiential Learning: the Bear River Fellows Program

    Science.gov (United States)

    Rosenberg, D. E.; Shirley, B.; Roark, M. F.

    2012-12-01

    The Department of Civil and Environmental Engineering, Outdoor Recreation, and Parks and Recreation programs at Utah State University (USU) have partnered to offer a new, unique river-based experiential learning opportunity for undergraduates called the Bear River Fellows Program. The program allows incoming freshmen Fellows to experience a river first hand during a 5-day/4-night river trip on the nearby Bear River two weeks before the start of their first Fall semester. As part of the program, Fellows will navigate the Bear River in canoes, camp along the banks, interact with local water and environmental managers, collect channel cross section, stream flow, vegetation cover, and topological complexity data, meet other incoming freshmen, interact with faculty and graduate students, develop boating and leadership skills, problem solve, and participate as full members of the trip team. Subsequently, Fellows will get paid as undergraduate researchers during their Fall and Spring Freshman semesters to analyze, synthesize, and present the field data they collect. The program is a collaborative effort between two USU academic units and the (non-academic) division of Student Services and supports a larger National Science Foundation funded environmental modelling and management project for the lower Bear River, Utah watershed. We have advertised the program via Facebook and emails to incoming USU freshmen, received 35 applications (60% women), and accepted 5 Fellows into the program (3 female and 2 male). The river trip departs August 14, 2012. The poster will overview the Bear River Fellows Program and present qualitative and preliminary outcomes emerging from the trip and Fellows' work through the Fall semester with the field data they collect. We will also undertake more rigorous and longer longitudinal quantitative evaluation of Program outcomes (for example, in problem-solving and leadership) both in Spring 2013 and in subsequent 2013 and 2014 offerings of the

  14. Velocity distribution of flow with submerged flexible vegetations based on mixing-length approach

    Institute of Scientific and Technical Information of China (English)

    Wen-xin HUAI; Jie HAN; Yu-hong ZENG; Xiang AN; Zhong-dong QIAN

    2009-01-01

    By choosing a PVC slice to simulate flexible vegetation, we carried out ex-periments in an open channel with submerged flexible vegetation. A 3D acoustic Doppler velocimeter (micro ADV) was used to measure local flow velocities and Reynolds stress. The results show that hydraulic characteristics in non-vegetation and vegetation layers are totally different. In a region above the vegetation, Reynolds stress distribution is linear, and the measured velocity profile is a classical logarithmic one. Based on the concept of new-riverbed, the river compression parameter representing the impact of vegetation on river is given, and a new assumption of mixing length expression is made. The formula for time-averaged velocity derived from the expression requires less parameters and simple calculation, and is useful in applications.

  15. Quantifying the effect of vegetation change on regional water balance within the Budyko Framework

    Science.gov (United States)

    Zhang, S.; Yang, D.

    2015-12-01

    Budyko framework is widely used to investigate impacts of climate and landscape changes on regional hydrology, but quantifying the effect of vegetation change is still a challenge due to the lack of an explicit expression of vegetation change in Budyko equations. This study attempts to establish a relationship between the change of landscape parameter in a Budyko equation and the change of vegetation (represented by NDVI) in Yellow River Basin and Hai River Basin of China, where vegetation and regional hydrology changed significantly during the past 30 years. It is found that the ratio of landscape parameter change to NDVI change has a good relationship with the aridity index, and thus vegetation change can be converted into landscape parameter change. Then the NDVI elasticity of runoff is introduced and formulized under the Budyko framework. It provides a useful tool for quantitative evaluation of regional hydrological response to vegetation change.

  16. Levantamento florístico do componente arbustivo-arbóreo da vegetação ciliar na bacia do rio Taperoá, PB, Brasil Floristic survey of components of shrub-tree riparian vegetation in the Taperoá river basin, Paraíba State, Brasil

    Directory of Open Access Journals (Sweden)

    Alecksandra Vieira de Lacerda

    2005-09-01

    Full Text Available Considerando o papel relevante e o nível de degradação presente nas áreas ciliares, a pesquisa objetivou estudar a composição florística do componente arbustivo-arbóreo da vegetação ciliar em diferentes ambientes hídricos do semi-árido paraibano na bacia do rio Taperoá. O levantamento florístico foi realizado no período de junho/2002 a fevereiro/2003 e abrangeu nove pontos distribuídos ao longo de rios, riachos, lagoa e açude. A definição das atividades apoiou-se em análise de cartas e mapas da vegetação em escala de 1:100.000 e caminhadas aleatórias que permitiram a realização de coleta de material vegetal, utilizado para identificação por meio de consultas a especialistas e de morfologia comparada, usando bibliografia especializada e análise das exsicatas depositadas no herbário Lauro Pires Xavier - JPB (UFPB, João Pessoa, PB. A vegetação arbustivo-arbórea da mata ciliar nos nove pontos amostrados foi representada por 43 espécies, das quais 41 são pertencentes a 19 famílias, e duas espécies permaneceram indeterminadas. As famílias que apresentaram o maior número de espécies foram Mimosaceae (sete, Caesalpiniaceae (cinco e Euphorbiaceae (cinco. Os resultados da análise de agrupamento indicaram que as áreas ciliares apresentaram certa particularização em termos de composição florística, o que se refletiu nos baixos índices de similaridades entre o conjunto de áreas amostradas.Considering the relevant role and the current level of degradation of riparian areas, this work aimed to study the floristic composition of shrub-tree riparian vegetation at different hydric environments in the Taperoá river basin, in the semi-arid region of the Paraíba State, Northeast Brazil. The survey was performed from June 2002 to February 2003. Nine sampling sites were distributed along rivers and streams, and around lagoon, and dam. The definition of activities was based on the analysis of charts and vegetation maps

  17. Vegetation aspects in the Lapus Valley

    Directory of Open Access Journals (Sweden)

    Monica MARIAN

    2007-05-01

    Full Text Available Vegetation aspects in the Lăpuş Valey vegetation. The Lăpuş Valey belong the Maramureş county. It’s situated in North of Transilvania and his territory covers few geomorphological units like: Rodna Mountains, the Maramureş Mountains, the Gutâi Mountains. The longest river wich crossed the county is Lăpuş. The climat is formed under the influence of dominantly western and north-western atmospheric flow and sheltered by the nerby mountains. The Lăpuş Mountins far from having impressing heights, are very fragmentated, with deep valleys and steep slopes, the river Lăpuş forming true quays. Near the Lăpuş Valey the peaks are covered with forest consist in special in beech forests with a few oak trees and small meadows of Nardus stricta and Agrostis stolonifera. Near the river they are also low forest edificated by Salix alba and Alnus glutinosa.

  18. Balkan Vegetation Database

    NARCIS (Netherlands)

    Vassilev, Kiril; Pedashenko, Hristo; Alexandrova, Alexandra; Tashev, Alexandar; Ganeva, Anna; Gavrilova, Anna; Gradevska, Asya; Assenov, Assen; Vitkova, Antonina; Grigorov, Borislav; Gussev, Chavdar; Filipova, Eva; Aneva, Ina; Knollová, Ilona; Nikolov, Ivaylo; Georgiev, Georgi; Gogushev, Georgi; Tinchev, Georgi; Pachedjieva, Kalina; Koev, Koycho; Lyubenova, Mariyana; Dimitrov, Marius; Apostolova-Stoyanova, Nadezhda; Velev, Nikolay; Zhelev, Petar; Glogov, Plamen; Natcheva, Rayna; Tzonev, Rossen; Boch, Steffen; Hennekens, Stephan M.; Georgiev, Stoyan; Stoyanov, Stoyan; Karakiev, Todor; Kalníková, Veronika; Shivarov, Veselin; Russakova, Veska; Vulchev, Vladimir

    2016-01-01

    The Balkan Vegetation Database (BVD; GIVD ID: EU-00-019; http://www.givd.info/ID/EU-00- 019) is a regional database that consists of phytosociological relevés from different vegetation types from six countries on the Balkan Peninsula (Albania, Bosnia and Herzegovina, Bulgaria, Kosovo, Montenegro

  19. Balkan Vegetation Database

    NARCIS (Netherlands)

    Vassilev, Kiril; Pedashenko, Hristo; Alexandrova, Alexandra; Tashev, Alexandar; Ganeva, Anna; Gavrilova, Anna; Gradevska, Asya; Assenov, Assen; Vitkova, Antonina; Grigorov, Borislav; Gussev, Chavdar; Filipova, Eva; Aneva, Ina; Knollová, Ilona; Nikolov, Ivaylo; Georgiev, Georgi; Gogushev, Georgi; Tinchev, Georgi; Pachedjieva, Kalina; Koev, Koycho; Lyubenova, Mariyana; Dimitrov, Marius; Apostolova-Stoyanova, Nadezhda; Velev, Nikolay; Zhelev, Petar; Glogov, Plamen; Natcheva, Rayna; Tzonev, Rossen; Boch, Steffen; Hennekens, Stephan M.; Georgiev, Stoyan; Stoyanov, Stoyan; Karakiev, Todor; Kalníková, Veronika; Shivarov, Veselin; Russakova, Veska; Vulchev, Vladimir

    2016-01-01

    The Balkan Vegetation Database (BVD; GIVD ID: EU-00-019; http://www.givd.info/ID/EU-00- 019) is a regional database that consists of phytosociological relevés from different vegetation types from six countries on the Balkan Peninsula (Albania, Bosnia and Herzegovina, Bulgaria, Kosovo, Montenegro

  20. Soil and vegetation surveillance

    Energy Technology Data Exchange (ETDEWEB)

    Antonio, E.J.

    1995-06-01

    Soil sampling and analysis evaluates long-term contamination trends and monitors environmental radionuclide inventories. This section of the 1994 Hanford Site Environmental Report summarizes the soil and vegetation surveillance programs which were conducted during 1994. Vegetation surveillance is conducted offsite to monitor atmospheric deposition of radioactive materials in areas not under cultivation and onsite at locations adjacent to potential sources of radioactivity.

  1. Flow resistance of vegetated oblique weir-like obstacles during high water stages

    NARCIS (Netherlands)

    Ali, S.; Uijttewaal, W.S.J.

    2011-01-01

    At high water stages obstacles in the floodplains of a river contribute to the flow resistance. In particular the elevated vegetated parts are expected to play an important role. The objective of this study is to estimate and parameterize the form drag due to vegetated oblique weir-like obstacles. A

  2. River nomads

    DEFF Research Database (Denmark)

    2016-01-01

    River nomads is a movie about people on the move. The documentary film explores the lifestyle of a group of nomadic fishermen whose mobility has been the recipe of success and troubles. Engaged in trade and travel, twice a year the river nomads form impressive convoys of majestic pirogues and set...... and liberated lifestyle and the breath-taking landscapes and vistas offered by the Niger River. River Nomads is also a personal account of the Kebbawa’s way of life and their current struggles as nomadic folk living in a world divided by borders and ruled by bureaucrats....

  3. Modeling of state of vegetation and soil erosion over large areas

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A vegetation-erosion model was developed to assess the extent of soil erosion and development trend of vegetation in the context of existing and contemplated vegetation-based soil erosion controls under different climatic, topographical and soil conditions. The model recognizes four vegetation-mediated soil erosion states: (i) an expanding vegetation coverage coupled with reduced erosion (C), (ii) a deteriorating vegetation coverage coupled with increased erosion (A), (iii) two transitional states between A and C, one with increasing erosion and vegetation coverage (B) and the other with decreasing erosion and vegetation coverage (D). With the model, the vegetation-erosion state of any particular area can be quantitatively described, by way of a vegetation-erosion chart, for varying climate, soil and topographic conditions, as demonstrated for the Xishan region, the East River basin, the Wangjiagou and Anjiagou watersheds (Loess Plateau), and the Xiaojiang watersheds (hot and dry valleys in the upper Yangtze River basin) in China. This paper presents the principles and results of area-specific investigations that track the fractions of the areas covered by vegetation and experiencing soil erosion (with soil loss determined in t/km2yr). This is done within the context of local soil erosion control initiatives via re-vegetation efforts, or the lack thereof, over the course of 30 years. The effectiveness of reforestation and erosion-control measures vary under different climatic, topographical and soil conditions. The vegetation may be quickly restored in the hot and wet East River basin but is very difficult on the dry and cold Loess Plateau. In the hot and dry valleys the vegetation can be restored if erosion is controlled and intensive reforestations for small watersheds are performed.

  4. Experimental and field investigations on uprooting of riparian vegetation

    Science.gov (United States)

    Calvani, Giulio; Francalanci, Simona; Solari, Luca; Gumiero, Bruna

    2017-04-01

    The morphology of a river reach is the result of many processes involving the motion of sediment (erosion, transport and deposition), the hydrological regime and the development and growth of vegetation. River evolution in the presence of vegetation depends on establishment of pioneer woody riparian seedlings on bars, and consequently on either their survival or death. Flooding events can cause young vegetation mortality by uprooting (Corenblit et al., 2007). These processes, despite their important implications on river morphodynamics, have been poorly investigated in the past. Most of previous research focused on the mechanism of root breakage and on measuring the vegetation resistance to uprooting in the vertical direction, while few works considered the effect of flow direction on the uprooting process (Bywater-Reyes et al., 2015). In this work, we focused on vegetation uprooting due to flow and to bed erosion. We considered two different types of vegetation: Avena Sativa, grown from seeds in external boxes, was used to investigate instantaneous uprooting, and Salix Purpurea, collected in the field, for delayed uprooting (namely type I and type II mechanisms, according to Edmaier et al., 2011). The experiments were carried out in a 5 m long flume in the Hydraulic Laboratory in Florence. A 2 m long mobile bed was build inside the flume, and vegetation was arranged according to several configurations on it. Both types of vegetation were subject to constant discharges to investigate the effects of a general bed degradation in modifying the occurrence of uprooting. We also performed some experiments with Avena Sativa located in a fixed bed and subjected to an increasing flow discharge in order to simulate instantaneous uprooting due to the action of hydrodynamic forces. We measured flow velocity, flow discharge and water depth and characterized vegetation by stem and root diameter, height and root length. The experimental results have been interpreted in terms of a

  5. MACROSCOPIC RIVERS

    NARCIS (Netherlands)

    VANDENBERG, IP

    1991-01-01

    We present a mathematical model for the ''river-phenomenon'': striking concentrations of trajectories of ordinary differential equations. This model of ''macroscopic rivers'' is formulated within nonstandard analysis, and stated in terms of macroscopes and singular perturbations. For a subclass, the

  6. The impact of flood variables on riparian vegetation

    Science.gov (United States)

    Dzubakova, Katarina; Molnar, Peter

    2016-04-01

    The riparian vegetation of Alpine rivers often grows in temporally dynamic riverine environments which are characterized by pronounced meteorological and hydrological fluctuations and high resource competition. Within these relatively rough conditions, riparian vegetation fulfils essential ecosystem functions such as water retention, biomass production and habitat to endangered species. The identification of relevant flood attributes impacting riparian vegetation is crucial for a better understanding of the vegetation dynamics in the riverine ecosystem. Hence, in this contribution we aim to quantify the ecological effects of flood attributes on riparian vegetation and to analyze the spatial coherence of flood-vegetation interaction patterns. We analyzed a 500 m long and 300-400 m wide study reach located on the Maggia River in southern Switzerland. Altogether five floods between 2008 and 2011 with return periods ranging from 1.4 to 20.1 years were studied. To assess the significance of the flood attributes, we compared post-flood to pre-flood vegetation vigour to flood intensity. Pre- and post-flood vegetation vigour was represented by the Normalized Difference Vegetation Index (NDVI) which was computed from images recorded by high resolution ground-based cameras. Flood intensity was expressed in space in the study reach by six flood attributes (inundation duration, maximum depth, maximum and total velocity, maximum and total shear stress) which were simulated by the 2D hydrodynamic model BASEMENT (VAW, ETH Zurich). We considered three floodplain units separately (main bar, secondary bar, transitional zone). Based on our results, pre-flood vegetation vigour largely determined vegetation reaction to the less intense floods (R = 0.59-0.96). However for larger floods with a strong erosive effect, its contribution was significantly lower (R = 0.59-0.68). Using multivariate regression analysis we show that pre-flood vegetation vigour and maximum velocity proved to be

  7. Studies on the Application Rate of Mg,B and Mo for Main Vegetables in Pearl River Delta%珠江三角洲几种主要蔬菜的镁硼钼适用量研究

    Institute of Scientific and Technical Information of China (English)

    李淑仪; 廖新荣; 蓝佩玲; 王荣萍; 邵鹏; 蔡绵聪; 肖旭林

    2011-01-01

    为获得珠江三角洲地区蔬菜中微量元素的合理用量,通过在2地进行3种蔬菜施镁、硼、钼的田间试验,研究三种元素不同配比对三种蔬菜的影响。结果显示:(1)不同品种的蔬菜对中微量元素的需求量不同;相同品种蔬菜在不同地点土壤上的施镁、硼、钼肥效应不同;相同蔬菜镁、硼、钼配施比单独使用的施用量可大幅度减少,尤其是硼和钼可减少50%。(2)在施氮磷钾基础上单独施用镁、硼、钼,菜心的Mg适施量约为13.350~15.750 kghm^-2;B的适施量约为0.990~1.065 kghm^-2;Mo的适施量为0.375~0.420 kg hm^-2。蒜青的Mg适施量约为1.500 kg hm^-2;B的适施量约为0.450 kg hm^-2;Mo的适施量为0.240 kg hm^-2。苦瓜的施硼适用量范围在1.050 kg hm^-2左右。(3)在施氮磷钾基础上镁、硼、钼配合施用,菜心的Mg适施量约为12.000 kghm^-2、B适施量约为0.450 kghm^-2、Mo适施量约为0.240 kghm^-2;苦瓜的Mg适施量约为12.000~18.000 kghm^-2、B适施量约为0.450~1.800 kg hm^-2、Mo适施量为0.120~0.240 kg hm^-2;蒜青的B和Mo适用量分别为0.900 kg hm^-2和0.210 kg hm^-2、镁的施用量则应〈1.350 kg hm^-2。(4)镁和硼的施用量不仅受试验地土壤交换性镁和有效硼含量水平的影响,还与土壤pH值和蔬菜目标产量有关。%Flowering Chinese cabbage(Brassica parachinensis Bailey),Garlic Plants(Allium Sativum L.) and Balsam pear(Momordica charantia L.) were main vegetables in southern China.The field experiments were carried out to study the rational application rates of magnesium,boron and molybdenum on these three vegetables in two soils.The results showed that:(1) The demands of middle-element and microelement varied between different varieties of vegetables,and the effects of Mg,B and Mo fertilizers on the same variety of vegetable also changed between different soils.The usage of middle-element and microelement could be

  8. Vegetation survey of PEN Branch wetlands

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

    A survey was conducted of vegetation along Pen Branch Creek at Savannah River Site (SRS) in support of K-Reactor restart. Plants were identified to species by overstory, understory, shrub, and groundcover strata. Abundance was also characterized and richness and diversity calculated. Based on woody species basal area, the Pen Branch delta was the most impacted, followed by the sections between the reactor and the delta. Species richness for shrub and groundcover strata were also lowest in the delta. No endangered plant species were found. Three upland pine areas were also sampled. In support of K Reactor restart, this report summarizes a study of the wetland vegetation along Pen Branch. Reactor effluent enters Indian Grove Branch and then flows into Pen Branch and the Pen Branch Delta.

  9. Responses of vegetation to climate change in the headwaters of China's Yellow River Basin based on zoning of dry and wet climate%黄河上游不同干湿气候区植被对气候变化的响应

    Institute of Scientific and Technical Information of China (English)

    杜加强; 舒俭民; 张林波; 郭杨

    2011-01-01

    Aims Precipitation and temperature are considered the limiting factors to vegetation growth in arid and cold areas, respectively. Our objective was to study the trends in vegetation cover and productivity and their relationships with prevailing hydrothermal factors in order to better understand climatic constraints on regional vegetation dynamics.Methods We zoned dry and wet climates using daily meteorological data from 1959 to 2008 at 16 locations in the headwaters of the Yellow River Basin to calculate the ratio of precipitation to evapotranspiration estimated with the FAO Penman-Monteith model. Based on this zoning, the temporal dynamics of vegetation and changes in climate were analyzed using the normalized difference vegetation index (NDVI) obtained from the NASA AVHRR sensor (1982-2006) and the GLOPEM net primary productivity (NPP) (1981-2000) and corresponding annual meteorological data. Then we developed the relationships between NDVI and NPP and climatic factors. Important findings The region studied is semi-humid in the southeast and semi-arid elsewhere, with a boundary nearly matching the 450 mm rainfall contour. The weather became wetter and especially warmer in most parts of the region during 1981-2006. The regional average NDVI and NPP markedly increased in semi-humid areas and slightly increased in semi-arid areas. Overall, NDVI had a significantly positive correlation with mean annual air temperature and a mainly negative correlation with mean annual precipitation in most semi-humid areas. The most important factor influencing NDVI was heat. In contrast, the key climatic factor affecting vegetation changes in the semi-arid areas was water, the relationship between NDVI and precipitation was strong and vegetation was more sensitive to changes in precipitation. The impact of climate change on NPP was similar to that on NDVI. Findings suggest that the responses of vegetation to climate change depend in part on the hydrothermal conditions of the region

  10. Vertical dispersion in vegetated shear flows

    Science.gov (United States)

    Rubol, Simonetta; Battiato, Ilenia; de Barros, Felipe P. J.

    2016-10-01

    Canopy layers control momentum and solute transport to and from the overlying water surface layer. These transfer mechanisms strongly dependent on canopy geometry, affect the amount of solute in the river, the hydrological retention and availability of dissolved solutes to organisms located in the vegetated layers, and are critical to improve water quality. In this work, we consider steady state transport in a vegetated channel under fully developed flow conditions. Under the hypothesis that the canopy layer can be described as an effective porous medium with prescribed properties, i.e., porosity and permeability, we model solute transport above and within the vegetated layer with an advection-dispersion equation with a spatially variable dispersion coefficient (diffusivity). By means of the Generalized Integral Transform Technique, we derive a semianalytical solution for the concentration field in submerged vegetated aquatic systems. We show that canopy layer's permeability affects the asymmetry of the concentration profile, the effective vertical spreading behavior, and the magnitude of the peak concentration. Due to its analytical features, the model has a low computational cost. The proposed solution successfully reproduces previously published experimental data.

  11. Experimental analysis of turbulence characteristics and flow conveyance effects in a vegetated channel

    Science.gov (United States)

    Termini, D.

    2009-04-01

    Natural rivers are characterized by a strong hydraulic and geomorphic complexity. Many studies conducted in this field (Malthus and Mumby, 2003; Muhar, 1996) show that the accurate estimation both of the river morphological changes and of local hydraulic characteristics of flow (i.e. the local flow velocities and water depths) is necessary for the restoration and protection of biodiversity. Vegetation is a key factor to analyze the interrelated system of flow, sediment transport, and morphodynamic in rivers (Tsujimoto, 1999; Maione et al., 2000). On one hand, some kind of species of vegetation affect the habitat conditions, being crucial to the maintenance of biodiversity (Larkum et al, 2004); on the other hand, effects of vegetation on flow velocity are significant and are of crucial importance for stabilizing sediments and reducing erosion along the channel. In particular, it has been generally agreed that vegetation increases flow resistance and modifies sediment transport and deposition (Tsujimoto et al., 1996; Yen 2002). The analysis of the hydrodynamic conditions in vegetated channels is complex because vegetation is flexible in varying degrees and it oscillates in the flow changing position. Furthermore, because of temporal changing of roughness due to natural vegetative growth, the response of vegetation to the flow can change in time. In this paper the flow over real flexible vegetation is experimentally studied. A 2D-ADV (Acoustic Doppler Velocimeter) is used to measure the local flow velocities, for different vegetation concentrations and varying the discharge and the flume slope. The influence of both vegetation concentration and depth/vegetation height ratio on the measured velocity profiles is analyzed. The comparison between the velocity distribution and the turbulence intensity distribution is also presented. The spectral analysis is operated in order to verify the formation of turbulence structures inside the vegetated layer and the flow conveyance

  12. 河岸带不同植被类型对土壤有机碳和全氮分布特征的影响——以北京地区温榆河为例%Effects of riparian vegetation on soil organic carbon and total nitrogen distribution——a case study of Wenyu River, Beijing

    Institute of Scientific and Technical Information of China (English)

    郭二辉; 孙然好; 陈利顶; 王赵明; 肖峻; 时鹏

    2012-01-01

    河岸带生态系统是河流生态系统和陆地生态系统之间的生态交错带,也是一个敏感和脆弱的生态区域.由于受河道周边人类活动的干扰,河岸带生态系统的植被类型发生了巨大变化.本文以北京市地区的温榆河为研究对象,分析了河岸带7种植被类型对土壤有机碳和全氮含量及其空间分布特征的影响.结果表明:(1)河岸带不同植被类型对土壤有机碳和全氮的影响主要表现在表层土壤,尤其是0~5 cm土层,而对5 cm以下土层的影响相对较小.(2)河岸带不同植被类型土壤全氮和有机碳含量的空间分布特征具有显著差异.随着土层深度增加,土壤全氮和有机碳整体上呈下降趋势,但不同植被类型的垂直变化规律有较大差异,如自然草地、退耕撂荒地和林地的土壤有机碳、全氮含量随土层深度加深而降低的速率明显高于农田生态系统.(3)在0~30 cm土壤剖面上,土壤有机碳平均含量从高到低依次为杨树林(9.54 g·kg-1)、自然荒草地(9.33 g·kg-1)、梨树果园(9.18 g·kg-1)、火炬树林地(8.89 g·kg-1)、退耕撂荒地(7.91 g·kg-1)、玉米地(7.22 g·kg-1)和黄豆地(7.17g·kg-1);土壤全氮的平均含量从高到低依次为自然荒草地(1.30 g·kg-1)、杨树林(0.91 g·kg-1)、梨树果园(0.90g·kg-1)、火炬树林地(0.83 g·kg-1)、退耕撂荒地(0.80 g·kg-1)、玉米地(0.72 g·kg-1)和黄豆地(0.70 g·kg-1).%Riparian ecosystem is an ecological ecotone that occurs between river and terrestrial ecosystems. Riparian ecosystems are normally sensitive and vulnerable ecological niches. There are vast changes in riparian vegetation systems due to human disturbances of river systems. Thus this study analyzed the effects of 7 riparian vegetation systems on the contents and spatial distributions of soil organic carbon and total nitrogen in Wenyu River in Beijing. The results showed that riparian vegetation mainly affected soil organic carbon

  13. Vegetation survey of Sengwa

    Directory of Open Access Journals (Sweden)

    G. C. Craig

    1983-12-01

    Full Text Available The approach and initial results of a vegetation survey of the Sengwa Wildlife Area are outlined. The objectives were to produce a vegetation classification and map sufficiently detailed to serve as a base for the management of the natural vegetation. The methods adopted consist of (a stratification of the area into homogeneous units using 1:10 000 colour aerial photographs; (b plotless random sampling of each stratum by recording cover abundance on the Braun-Blaunquet scale for all woody species; and (c analysis of the data by indicator species analysis using the computer programme 'Twinspan’. The classification produced is successful in achieving recognizable vegetation types which tie in well with known environmental features.

  14. Description of vegetation types

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document provides descriptions of five vegetation types found in Iowa- oak savannah, mature hardwoods, floodplain woods, scrub woods, and riparian woods. Oak...

  15. Total Vegetation 1992

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The coverage contains 1992 vegetation polygons representing GCES monitoring sites. These data were developed by Dr. G. Waring Northern AZ. University for use in the...

  16. Total Vegetation 1973

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The coverage contains 1973 vegetation polygons representing GCES monitoring sites. These data were developed as study by Dr. G. Waring Northern AZ. University of...

  17. Total Vegetation 1965

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The coverage contains 1965 vegetation polygons representing GCES monitoring sites. These data were developed as study by Dr. G. Waring Northern AZ. University of...

  18. Total Vegetation 1984

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The coverage contains 1984 vegetation polygons representing GCES monitoring sites. These data were developed as study by Dr. G. Waring Northern AZ. University of...

  19. Research on the Management Model of Flora and Vegetation Recovery of Wanquan River Basin in Hainan Province%海南省万泉河流域植物区系及植被恢复经营模式研究

    Institute of Scientific and Technical Information of China (English)

    佘济云; 胡焕香; 李俊; 周丹华; 郭霞

    2012-01-01

    为了更好地保护、开发和利用海南省万泉河流域的植物资源,探讨科学、合理的植被恢复经营模式,在广泛查阅文献与外业调查的基础上,对海南省万泉河流域植物区系进行了初步研究.结果表明:(1)共记录到维管植物546种及种下单位,隶属于138科411属,其中蕨类植物19科27属38种,裸子植物4科6属6种,被子植物115科378属502种;(2)种子植物中含10种以上的科有9个,含4种以上的属有7个;(3)种子植物科和属分别对应有11个和14个分布区类型,且二者的泛热带成分分别占非世界分布的62.8%和32.6%;(4)中国特有属数量稀少,只有3个,占非世界属总数的0.82%;(5)有针对性地提出了造林更新、封山育林、抚育间伐、幼林抚育、补植改造、退果还林6种植被恢复的经营模式.说明万泉河流域植物资源丰富,被子植物占有绝对优势,科、属分化程度较高,区系优势现象比较明显,植物分布类型多样,地理成分复杂,具有明显的热带、亚热带性质.%In order to protect, develop and utilize the plant resource of Wanquan River basin in Hainan Province better, discuss the scientific and reasonable management model of vegetation recovery, the author had conducted a preliminary study to flora of Wanquan River basin in Hainan Province based on lots of consultation of literatures and field investigations. The results showed that: (1) there were recorded vascular plants 546 families and infraspecies, contained vascular plants 138 families, 411 genera: pteridophytes 19 families, 27 genera, 38 species; gymnosperms 4 families, 6 genera, 6 species; angiosperms 115 families, 378 genera, 502 species; (2) There were 9 families of spermatophyte with more than 10 species,7 genera of spermatophyte with more than 4 species; (3) Areal-types of families and genera of spermatophyte were 11 and 14, pan-tropical elements of the two occupied 62.8% and 32.6% of the non-world distribution

  20. Authentication of vegetable oils.

    OpenAIRE

    Cunha, S.C.; Amaral, J S; Oliveira, M.B.P.P.

    2011-01-01

    Authenticity of vegetable oils continues to be a challenge and the target of many studies. Consumers expectancy on healthier products that conform to the labelled information, and the vast amount of legislation a bout the correct characterisation and classification of vegetable oils have boosted a number of scientific works on this subject. Analytical t echniques to face this challenge are, at least, as manifold as ar e the ways of adulteration, ranging fro...

  1. Treatment of vegetable oils

    Energy Technology Data Exchange (ETDEWEB)

    Bessler, T.R.

    1986-05-13

    A process is described for preparing an injectable vegetable oil selected from the group consisting of soybean oil and sunflower oil and mixtures thereof which comprise: (a) first treating the vegetable oil at a temperature of 80/sup 0/C to about 130/sup 0/C with an acid clay; (b) deodorizing the vegetable oil with steam at a temperature of 220/sup 0/C to about 280/sup 0/C and applying a vacuum to remove volatilized components; (c) treating the deodorized vegetable oil, at a temperature of from about 10/sup 0/C to about 60/sup 0/C, with an acid clay to reduce the content of a member selected from the group consisting of diglycerides, tocopherol components, and trilinolenin and mixtures thereof, wherein the acid clay is added in a weight ratio to the deoderized vegetable oil of from about 1:99 to about 1:1; and (d) thereafter conducting a particulate filtration to remove a substantial portion of the acid clay from the vegetable oil, wherein the filtration is accomplished with filters having a pore size of from about 0.1 to 0.45 microns, thereby obtaining the injectable oil.

  2. Nitrogen and phosphorus in the Upper Mississippi River: Transport, processing, and effects on the river ecosystem

    Science.gov (United States)

    Houser, J.N.; Richardson, W.B.

    2010-01-01

    Existing research on nutrients (nitrogen and phosphorus) in the Upper Mississippi River (UMR) can be organized into the following categories: (1) Long-term changes in nutrient concentrations and export, and their causes; (2) Nutrient cycling within the river; (3) Spatial and temporal patterns of river nutrient concentrations; (4) Effects of elevated nutrient concentrations on the river; and (5) Actions to reduce river nutrient concentrations and flux. Nutrient concentration and flux in the Mississippi River have increased substantially over the last century because of changes in land use, climate, hydrology, and river management and engineering. As in other large floodplain rivers, rates of processes that cycle nitrogen and phosphorus in the UMR exhibit pronounced spatial and temporal heterogeneity because of the complex morphology of the river. This spatial variability in nutrient processing creates clear spatial patterns in nutrient concentrations. For example, nitrate concentrations generally are much lower in off-channel areas than in the main channel. The specifics of in-river nutrient cycling and the effects of high rates of nutrient input on UMR have been less studied than the factors affecting nutrient input to the river and transport to the Gulf of Mexico, and important questions concerning nutrient cycling in the UMR remain. Eutrophication and resulting changes in river productivity have only recently been investigated the UMR. These recent studies indicate that the high nutrient concentrations in the river may affect community composition of aquatic vegetation (e. g., the abundance of filamentous algae and duckweeds), dissolved oxygen concentrations in off-channel areas, and the abundance of cyanobacteria. Actions to reduce nutrient input to the river include changes in land-use practices, wetland restoration, and hydrological modifications to the river. Evidence suggests that most of the above methods can contribute to reducing nutrient concentration in

  3. Vegetation Mapping of the Mond Protected Area of Bushehr Province (South-west Iran)

    Institute of Scientific and Technical Information of China (English)

    Ahmadreza Mehrabian; Alireza Naqinezhad; Abdolrassoul Salman Mahiny; Hossein Mostafavi; Homan Liaghati; Mohsen Kouchekzadeh

    2009-01-01

    Add regions of the wodd occupy up to 35% of the earth's surface, the basis of various definitions of climatic conditions,vegetation types or potential for food production. Due to their high ecological value, monitoring of add regions is necessary and modem vegetation studies can help in the conservation and management of these areas. The use of remote sensing for mapping of desert vegetation is difficult due to mixing of the spectral reflectance of bright desert soils with the weak spectral response of sparse vegetation. We studied the vegetation types in the semiarid to arid region of Mond Protected Area, south-west Iran, based on unsupervised classification of the Spot XS bands and then produced updated maps.Sixteen map units covering t2 vegetation types were recognized in the area based on both field works and satellite mapping. Halocnemum strobilaceum and Suaeda fruticosa vegetation types were the dominant types and Ephedra foliata,Salicornia europaaa-Suaeda heterophylla vegetation types were the smallest. Vegetation coverage decreased sharply with the increase in salinity towards the coastal areas of the Persian Gulf. The highest vegetation coverage belonged to the riparian vegetation along the Mond River, which represents the northern boundary of the protected area. The location of vegetation types was studied on the separate soil and habitat diversity maps of the study area, which helped in final refinements of the vegetation map produced.

  4. 玛纳斯河流域荒漠植被单株茎干液流及光合蒸腾特性研究%Study of Liquid Flow and the Characteristics of Photosynthesis and Transpiration of Vegetation Plant Stems in Manasi River Basin

    Institute of Scientific and Technical Information of China (English)

    陈思; 何新林; 杨广; 许双堆; 杨文新

    2014-01-01

    植物茎干液流量可表征其蒸腾耗水量,反映植被水分传输状况,可用于计算植被生态需水量。以玛纳斯河流域古尔班通古特沙漠南缘典型荒漠植被梭梭、柽柳为研究对象,通过数据监测,研究植被茎干液流及光合蒸腾特性,分析气象因子及土壤含水率对茎干液流的影响。结果表明:梭梭、柽柳茎干液流速率呈明显的昼夜变化规律,白天液流速率远高于夜间;梭梭的净光合速率日变化模式为双峰型,柽柳为单峰型;梭梭蒸腾速率的日变化有明显上升和下降过程,柽柳趋势不明显,呈小幅震荡;液流速率变化与相对空气湿度呈负相关,空气湿度高时液流速率低;气温、总辐射与液流速率的变化趋势基本一致,液流速率随着气温或总辐射的增强而增大;随着土壤含水率降低,液流速率降低。%Plant stem sap flow of water consumption ,that reflects the status of vegetation water transmission ,and determines the vegetation ecological water requirement .Research's study objectn is Haloxylon ammodendron and Tamarix vegetation that in the southern Gurbantunggut Desert of Manasi River Basin ,Through the data monitoring to research the liquid flow and the characteris-tics of photosynthesis and transpiration of vegetation stem ,and analysis of the effect on the stem sap flow of meteorological factors and soil moisture content .The results show that :Haloxylon ammodendron and Tamarix stem sap flow rate showed a significant di-urnal variation ,the flow rate is much higher than the night .Changes in net photosynthetic rate of Haloxylon ammodendron mode light of day is shuangfeng type and Tamarix chinensis belong to Single peak type .Diurnal changes of transpiration rate of Haloxylon ammodendron had the obvious rise and fall ,but Tamarix tendency is not obviously .The liquid flow rate was negatively correlated with relative humidity of the air ,and the change trend

  5. Verification of watershed vegetation restoration policies, arid China

    Science.gov (United States)

    Zhang, Chengqi; Li, Yu

    2016-07-01

    Verification of restoration policies that have been implemented is of significance to simultaneously reduce global environmental risks while also meeting economic development goals. This paper proposed a novel method according to the idea of multiple time scales to verify ecological restoration policies in the Shiyang River drainage basin, arid China. We integrated modern pollen transport characteristics of the entire basin and pollen records from 8 Holocene sedimentary sections, and quantitatively reconstructed the millennial-scale changes of watershed vegetation zones by defining a new pollen-precipitation index. Meanwhile, Empirical Orthogonal Function method was used to quantitatively analyze spatial and temporal variations of Normalized Difference Vegetation Index in summer (June to August) of 2000-2014. By contrasting the vegetation changes that mainly controlled by millennial-scale natural ecological evolution with that under conditions of modern ecological restoration measures, we found that vegetation changes of the entire Shiyang River drainage basin are synchronous in both two time scales, and the current ecological restoration policies met the requirements of long-term restoration objectives and showed promising early results on ecological environmental restoration. Our findings present an innovative method to verify river ecological restoration policies, and also provide the scientific basis to propose future emphasizes of ecological restoration strategies.

  6. Towards Biological Restoration of Tehran Megalopolis River Valleys- Case Study: Farahzad River

    Science.gov (United States)

    Samadi, Nafishe; Oveis Torabi, Seyed; Akhani, Hossein

    2017-04-01

    Towards biological restoration of Tehran megalopolis river-valleys: case study Farahzad river 1Nafiseh Samadi, 2OveisTorabi, 3Hossein Akhani 1Mahsab Shargh Company, Tehran ,Iran, nafiseh19@gmail.com 2 Mahsab Shargh Company, Tehran ,Iran, weg@tna-co.com 3Department of Plant Sciences, Halophytes and C4 Research Laboratory, School of Biology, College of Sciences, University of Tehran, PO Box 14155-6455, Tehran, Iran, akhani@khayam.ut.ac.ir Tehran is located in northcentral parts of Iran on the alluvium of southern Alborz Mountains. Seven rivers originated from the highlands of N Tehran run inside and around the city. Many of these river valleys have been deformed by a variety of urban utilizations such as garden, building, canal, park, autobahn etc. Tehran with more than eight million populations suffered from adverse environmental conditions such as pollution and scarcity of natural habitats for recreational activities. Ecological restoration of altered river valleys of Tehran is one of the priorities of Tehran municipality started as a pilot project in Farahzad river. Intensive disturbance, conversion into various urban utilization, illegal building construction, waste water release into the river, garbage accumulation, artificial park constructions and domination of invasive species have largely altered the river. Parts of the river located in Pardisan Nature Park was studied before its complete deformation into a modern park. The riparian vegetation consisted of Tamarix ramosissima and Salix acmophylla shrubs with large number of aquatic and palustric plants. The norther parts of the river still contain semi-natural vegetation which change into patchy and intensive degraded habitats towards its southern parts. In northern parts of valley there are old gardens of Morus alba and Juglans regia, and planted trees such as Plataneus oreientalis and Acer negundo. Salix acmophylla, Fraxinus excelsior and Celtis caucasica are native species growing on river margin or

  7. Development of freeze dried vegetables

    Science.gov (United States)

    Larson, R. W.

    1970-01-01

    The development of freeze dried vegetables to be used in the Apollo food system is discussed. After the initial selection and screening of vegetables, several types of freeze dried vegetables were prepared in small batches. From these small batches, two vegetables were judged satisfactory for further testing and evaluation. These vegetables, mashed potatoes and asparagus, were subjected to storage at 100 deg plus or minus 5 F. for two weeks and then taste tested. The vegetables were also tested to determine if they complied with the microbiological requirements for Apollo food. The space food prototype production guide for the vegetables is submitted.

  8. Assessment of River Habitat Quality in the Hai River Basin, Northern China

    Directory of Open Access Journals (Sweden)

    Yuekui Ding

    2015-09-01

    Full Text Available We applied a river habitat quality (RHQ assessment method to the Hai River Basin (HRB; an important economic centre in China; to obtain baseline information for water quality improvement; river rehabilitation; and watershed management. The results of the assessment showed that the river habitat in the HRB is seriously degraded. Specifically; 42.41% of the sites; accounting for a river length of 3.31 × 104 km; were designated poor and bad. Habitat in the plain areas is seriously deteriorated; and nearly 50% of the sites; accounting for a river length of 1.65 × 104 km; had either poor or bad habitats. River habitat degradation was attributable to the limited width of the riparian zone (≤5 m; lower coverage of riparian vegetation (≤40%; artificial land use patterns (public and industrial land; frequent occurrence of farming on the river banks and high volumes of solid waste (nearly 10 m3; single flow channels; and rare aquatic plants (≤1 category. At the regional scale; intensive artificial land use types caused by urbanization had a significant impact on the RHQ in the HRB. RHQ was significantly and negatively correlated with farmland (r = 1.000; p < 0.01 and urban land (r = 0.998; p < 0.05; and was significantly and positively correlated with grassland and woodland (r = 1.000; p < 0.01. Intensive artificial land use; created through urbanization processes; has led to a loss of the riparian zone and its native vegetation; and has disrupted the lateral connectivity of the rivers. The degradation of the already essentially black rivers is exacerbated by poor longitudinal connectivity (index of connectivity is 2.08–16.56; caused by reservoirs and sluices. For river habitat rehabilitation to be successful; land use patterns need to be changed and reservoirs and sluices will have to be regulated.

  9. Study on vegetation ecological water requirement in Ejina Oasis

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Ecological Water Requirement (EWR) of desert oasis is the amount of water required to maintain a normal growth of vegetation in the special ecosystems. In this study EWR of the Ejina desert oasis is estimated through the relational equation between normalized difference vegetation index (NDVI), productivity and transpiration coefficient, which was established by a combination of the RS, GIS, GPS techniques with the field measurements of productivity. The results show that about 1.53×108 m3 water would be needed to maintain the present state of the Ejina Oasis, and the ecological water requirement would amount to 3.49×108 m3 if the existing vegetation was restored to the highest productivity level at present. Considering the domestic water requirement, river delivery loss, oasis vegetation water con-sumption, farmland water demand, precipitation recharge, etc., the draw-off discharge of the Heihe River (at Longxin Mount) should be 1.93×108―2.23 ×108 m3 to maintain the present state of the Ejina Oasis, and 4.28×108―5.17×108 m3 to make the existing vegetation be restored to the highest productiv-ity level at present.

  10. Interspecific association of dominant species of wetland vegetation in the middle and lower reaches of Fenhe River, Shanxi province of China%汾河流域中下游湿地植被优势种种间关联性分析

    Institute of Scientific and Technical Information of China (English)

    王慧敏; 庞春花; 张峰; 赵彩莉

    2012-01-01

    采用x2检验、Pearson相关系数及Spearman秩相关系数检验等数量分析方法对汾河流域中下游湿地植被的34个优势种,共561个种对间的关联性进行定量研究.结果表明:x2检验有178个种对呈正相关,256个种对呈负相关,正负关联比为0.70;Pearson相关系数检验有157个种对呈正相关,402个种对呈负相关,正负关联比为0.39;Spearman秩相关系数检验有216个种对呈正相关,343个种对呈负相关,正负关联比为0.63;与x2检验和Pearson相关系数相比,Spearman秩相关系数检验具有较高的灵敏度.561个种对中负关联居多,达到极显著或显著的种对少,说明汾河流域中下游湿地植被群落处于演替初期.根据这34个优势种群对环境的适应方式和主导生态因素辅助以PCA排序,可将它们划分为4种生态种组.%By using x2-test, Pearson' s correlation coefficient, and Spearman' s rank correlation coefficient, a quantitative study was made on the interspecific association among the 561 species pairs of 34 dominant plant species of wetland vegetation in the middle and lower reaches of Fenhe River. The x2-test showed that among the 561 species pairs, 178 pairs were positively while 256 pairs were negatively correlated, and the correlation ratio was 0. 70. Pearson' s correlation coefficient test showed that 157 pairs were positively while 402 pairs were negatively correlated, and the correlation ratio was 0. 39. Spearman' s rank correlation coefficient test showed that 216 pairs were positively while 343 pairs were negatively correlated, and the correlation ratio was 0. 63. As compared with x2 -test and Pearson' s correlation coefficient, Spearman' s rank correlation coefficient was more sensitive. Most of the total 561 species pairs did not show significant association. The results indicated that the wetland vegetation in the middle and lower reaches of Fenhe River was at the early stage of succession. According to the adaptation to the

  11. The Vegetables Turned:

    DEFF Research Database (Denmark)

    Carter, Dale

    2009-01-01

    lyricist Van Dyke Parks, the incongruous, semantically complex figure of the vegetable came to illuminate aspects of psychedelic consciousness and - part by design, part by accident - the link between LSD and Anglo-American popular music. It threw light, too, on the scope and limits of changes...

  12. Grains and Starchy Vegetables

    Science.gov (United States)

    ... Starchy Vegetables Fats Alcohol What Can I Drink? Fruit Dairy Food Tips Eating Out Quick Meal Ideas Snacks Nutrient Content Claims Understanding Carbohydrates Types of Carbohydrates Carbohydrate Counting Make Your Carbs Count Glycemic Index Low-Calorie Sweeteners Sugar and Desserts Fitness Exercise & ...

  13. Coma / Vegetative State

    Science.gov (United States)

    ... a coma? A coma is a profound or deep state of unconsciousness (consciousness being the awareness of the ... opening or making sounds) than a person in deep coma. Characteristics of the vegetative state include: Return of a sleep-wake cycle with ...

  14. The Vegetables Turned:

    DEFF Research Database (Denmark)

    Carter, Dale

    2009-01-01

    lyricist Van Dyke Parks, the incongruous, semantically complex figure of the vegetable came to illuminate aspects of psychedelic consciousness and - part by design, part by accident - the link between LSD and Anglo-American popular music. It threw light, too, on the scope and limits of changes...

  15. Temperature sensitivity of soil methane production potential in different marsh vegetation zones in the Min River estuary%闽江口不同沼泽植被带土壤甲烷产生潜力的温度敏感性

    Institute of Scientific and Technical Information of China (English)

    杨平; 何清华; 仝川

    2015-01-01

    2012年2月采集闽江河口鳝鱼滩短叶茳芏(Cyperus malaccensis),芦苇(Phragmites australis)和互花米草(Scirpus alterniflora)3个典型潮汐沼泽植被带0~30cm(间隔5cm)土壤样品,在不同温度(10,20和30℃)进行15d室内厌氧培养实验,探讨河口区不同沼泽植被带土壤甲烷产生潜力及其温度敏感性(Q10值)的特征.结果表明,指数模型较好地拟合不同沼泽植被带土壤甲烷产生与温度的相关关系;温度由10℃升至20℃时,3个沼泽植被带土壤甲烷产生潜力 Q10值的均值分别为5.04,14.92和14.81,最大值均在培养期间的第13~15d 分别出现于10~15cm,15~20cm和20~25cm三个土层;温度由20℃升至30℃时,3个沼泽植被带土壤甲烷产生潜力Q10值的均值分别为3.56,4.99和3.43,最大值分别在培养期间的第4~6d,第4~6d和第7~9d出现于0~5cm,0~5cm和15~20cm三个土层;植被类型和土壤深度对甲烷产生潜力及Q10值均具有显著的影响(P<0.05).%Quantifying response of soil methane production potential to temperature change in different wetland vegetation are vital to accurately evaluate effect of climate change on wetland ecosystem carbon balance. Soil samples at a depth of 0~30cm (5cm interval) from three typical tidal marsh ecosystems dominated byCyperus malaccensis, Phragmites australis andSpartina alterniflora, respectively, in the Min River estuary were collected in February 2012, and soil methane production potentials were determined using anaerobic incubation method. The results showed that there is an exponential correlation between methane production potential and soil temperature. The averagedQ10 value of three marsh vegetation zones were 5.04, 14.92, 14.81, and 3.56, 4.99, 3.43, respectively, with temperature rasing from 10 to 20℃ and from 20 to 30℃. Vegetation type, incubation temperature and soil depth had significant effects on the methane production potential andQ10 value (P<0.05).

  16. Downstream ecosystem responses to middle reach regulation of river discharge in the Heihe River Basin, China

    Science.gov (United States)

    Zhao, Yan; Wei, Yongping; Li, Shoubo; Wu, Bingfang

    2016-11-01

    Understanding the oasis ecosystem responses to upstream regulation is a challenge for catchment management in the context of ecological restoration. This empirical study aimed to understand how oasis ecosystems, including water, natural vegetation and cultivated land, responded to the implementation of the Ecological Water Diversion Project (EWDP) in the Heihe River in China. The annual Landsat images from 1987 to 2015 were firstly used to characterize the spatial extent, frequency index and fractional coverage (for vegetation only) of these three oasis ecosystems and their relationships with hydrological (river discharge) and climatic variables (regional temperature and precipitation) were explored with linear regression models. The results show that river regulation of the middle reaches identified by the discharge allocation to the downstream basin experiences three stages, namely decreasing inflow (1987-1999), increasing inflow (2000-2007) and relative stable inflow (2008-2015). Both the current and previous years' combined inflow determines the surface area of the terminal lake (R2 = 0.841). Temperature has the most significant role in determining broad vegetation distribution, whereas hydrological variables had a significant effect only in near-river-channel regions. Agricultural development since the execution of the EWDP might have curtailed further vegetation recovery. These findings are important for the catchment managers' decisions about future water allocation plans.

  17. Spatial Vegetation Data for Acadia National Park Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — The U.S. Geological Survey (USGS) Upper Midwest Environmental Sciences Center (UMESC) has produced the Vegetation Spatial Database Coverage (vegetation map) for the...

  18. 76 FR 36515 - Rangeland Allotment Management Planning on the Fall River and Oglala Geographic Areas, Pine Ridge...

    Science.gov (United States)

    2011-06-22

    ... Forest Service Rangeland Allotment Management Planning on the Fall River and Oglala Geographic Areas... Allotment Management Planning on the Fall River West Geographic Area of the Fall River Ranger District and... prepare an environmental impact statement (EIS) analyzing the management of rangeland vegetation resources...

  19. Modelling of bio-morphodynamics in braided rivers: applications to the Waitaki river (New Zealand)

    Science.gov (United States)

    Stecca, G.; Zolezzi, G.; Hicks, M.; Measures, R.; Bertoldi, W.

    2016-12-01

    The planform shape of rivers results from the complex interaction between flow, sediment transport and vegetation processes, and can evolve in time following a change in these controls. The braided planform of the lower Waitaki (New Zealand), for instance, is endangered by the action of artificially-introduced alien vegetation, which spread after the reduction in magnitude of floods following hydropower dam construction. These processes, by favouring the flow concentration into the main channel, would likely promote a shift towards single thread morphology if vegetation was not artificially removed within a central fairway. The purpose of this work is to address the future evolution of these river systems under different management scenarios through two-dimensional numerical modelling. The construction of a suitable model represents a task in itself, since a modelling framework coupling all the relevant processes is not straightforwardly available at present. Our starting point is the GIAMT2D numerical model, solving two-dimensional flow and bedload transport in wet/dry domains, and recently modified by the inclusion of a rule-based bank erosion model. We further develop this model by adding a vegetation module, which accounts in a simplified manner for time-evolving biomass density, and tweaks the local flow roughness, critical shear stress for sediment transport and bank erodibility accordingly. We plan to apply the model to address the decadal-scale evolution of one reach in the Waitaki river, comparing different management scenarios for vegetation control.

  20. Microbial Contamination of Raw Vegetables in Ahvaz, Iran during 2014-2015

    Directory of Open Access Journals (Sweden)

    Abdol Kazem Neisi

    2016-07-01

    Full Text Available Background & Aims of the Study: Vegetables are useful for humans as they contain minerals, vitamins, fiber and other nutrients. Eating raw vegetables are a nutritional habit in Iranian families. Raw eating vegetables is the main source of parasitic infections. The aim of this study was to determine microbial contamination of raw vegetables in Ahvaz, Iran during 2014-2015. Materials and Methods: In this study, 20 samples collected from markets of Ahvaz. Average weight of collecting raw vegetables was 1 to 2 kilograms. Then, raw vegetables were washed by 4 to 5 liter tap water. For parasitic ova washed water leaved for 24 hours for sedimentation and then the supernatant poured and about 50 to 100 milliliter of settled water transferred to 15 ml centrifugal tubes. After centrifugation, pellet floated and finally parasitic ova were observed microscopically (corrected Bailenger method. The multiple tube method used for Coliform bacteria (Total & Faecal examination. Results: Maximum Coliform bacteria was in Kootabdullah samples (total Coliform was 25893319.52 MPN/100ml and Fecal Coliform was 15054572.83 MPN/100ml. Maximum Ascaris ova in Hamidieh was 43.3 per liter and Sheiban 36.66 per litter. Conclusion: Microbial contamination of raw vegetables, especially in Kootabdullah, possibly was due to Karoon river water pollution by sewage discharge of Ahvaz city, and also in Hamidieh possibly due to Karkheh river water pollution by sewage discharge of Hamidieh city. Thus, sewage treatment of these cities before discharging in rivers is necessary.

  1. Vegetation survey: a new focus for Applied Vegetation Science

    NARCIS (Netherlands)

    Chytry, M.; Schaminee, J.H.J.; Schwabe, A.

    2011-01-01

    Vegetation survey is an important research agenda in vegetation science. It defines vegetation types and helps understand differences among them, which is essential for both basic ecological research and applications in biodiversity conservation and environmental monitoring. In this editorial, we re

  2. Review of Vegetable Market Development in China

    Institute of Scientific and Technical Information of China (English)

    Chaoping; LUO; Yuandong; NI; Qiong; ZHAI

    2013-01-01

    This paper has reviewed vegetable market development from vegetable circulation system, the develop history of the liberalize vegetable market and the growth of the vegetable wholesale market in China. From the development of vegetables market in China and its characteristics: the development of vegetable market in China is related to vegetable market system, the change of institution, some technology development and infrastructure. this paper has put forward some related measures to perfect the vegetable market and improve the vegetable circulation efficiency in China.

  3. NESDIS VIIRS Green Vegetation Fraction

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains weekly Green Vegetation Fraction (GVF) derived from VIIRS. The Green Vegetation Fraction product is updated daily and is used as an input to...

  4. Heat Fluxes and River Energy Budget on the Example of Lowland Świder River

    Directory of Open Access Journals (Sweden)

    Łaszewski Maksym

    2015-03-01

    Full Text Available The paper present the energy budget of the downstream part of lowland Świder River, right tributary of the Vistula River in Mazovian Lowland, Poland. Heat fluxes were calculated on the example of four days, representing different meteorological and vegetative conditions. Results confirmed the dominant role of radiation, which accounted for an average of 90.7% and 79.7% gains and losses of thermal energy. Participation of non-radiative components proved to be far less crucial; the average contribution of condensation, sensible heat transfer, bed conduction and friction in energy gains accounted respectively to 0.0%, 0.6%, 2.9% and 5.9%, while the average contribution of evaporation, sensible heat transfer and bed conduction in energy losses reached respectively 4.5%, 1.1% and 14.6%. The results showed significant effect of riparian vegetation and cloud cover on river heat fluxes

  5. Decline of woody vegetation in a saline landscape in the Groundnut Basin, Senegal

    DEFF Research Database (Denmark)

    Sambou, Antoine; Theilade, Ida; Fensholt, Rasmus

    2016-01-01

    Several studies have documented that vegetation in the Sahel is highly dynamic and is affected by the prevailing climatic conditions, as well as by human use of the areas. However, little is known about vegetation dynamics in the large saline areas bordering the rivers of West Africa. Combining...... cover, herbaceous cover and tans (highly saline areas with sparse vegetation). Although the trend was the same, the three villages had different vegetation histories. A survey of the woody vegetation showed that shrubs and young trees were dominating with relatively few large trees. Local people...... perceived a general decline of woody plants from 1993 to 2013. Among 60 species mentioned by local people, 90 % were declining and 10 % increasing. Together the three methods documented a decrease in density and diversity of the woody vegetation, mainly influenced by salinity and land use. The large numbers...

  6. Hazard assessment of vegetated slopes

    NARCIS (Netherlands)

    Norris, J.E.; Greenwood, J.R.; Achim, A.; Gardiner, B.A.; Nicoll, B.C.; Cammeraat, E.; Mickovski, S.B.; Norris, J.E.; Stokes, A.; Mickovski, S.B.; Cammeraat, E.; van Beek, R.; Nicoll, B.C.; Achim, A.

    2008-01-01

    The hazard assessment of vegetated slopes are reviewed and discussed in terms of the stability of the slope both with and without vegetation, soil erosion and the stability of the vegetated slope from windthrow and snow loading. Slope stability can be determined by using either limit equilibrium or

  7. Hazard assessment of vegetated slopes

    NARCIS (Netherlands)

    J.E. Norris; J.R. Greenwood; A. Achim; B.A. Gardiner; B.C. Nicoll; E. Cammeraat; S.B. Mickovski

    2008-01-01

    The hazard assessment of vegetated slopes are reviewed and discussed in terms of the stability of the slope both with and without vegetation, soil erosion and the stability of the vegetated slope from windthrow and snow loading. Slope stability can be determined by using either limit equilibrium or

  8. Spatiotemporal variations of vegetation cover on the Chinese Loess Plateau(1981―2006):Impacts of climate changes and human activities

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Spatiotemporal variations of Chinese Loess Plateau vegetation cover during 1981-2006 have been investigated using GIMMS and SPOT VGT NDVI data and the cause of vegetation cover changes has been analyzed, considering the climate changes and human activities. Vegetation cover changes on the Loess Plateau have experienced four stages as follows: (1) vegetation cover showed a continued increasing phase during 1981―1989; (2) vegetation cover changes came into a relative steady phase with small fluctuations during 1990―1998; (3) vegetation cover declined rapidly during 1999―2001; and (4) vegetation cover increased rapidly during 2002―2006. The vegetation cover changes of the Loess Plateau show a notable spatial difference. The vegetation cover has obviously increased in the Inner Mongolia and Ningxia plain along the Yellow River and the ecological rehabilitated region of Ordos Plateau, however the vegetation cover evidently decreased in the hilly and gully areas of Loess Plateau, Liupan Mountains region and the northern hillside of Qinling Mountains. The response of NDVI to climate changes varied with different vegetation types. NDVI of sandy land vegetation, grassland and cultivated land show a significant increasing trend, but forest shows a decreasing trend. The results obtained in this study show that the spatiotemporal variations of vegetation cover are the outcome of climate changes and human activities. Temperature is a control factor of the seasonal change of vegetation growth. The increased temperature makes soil drier and unfavors vegetation growth in summer, but it favors vegetation growth in spring and autumn because of a longer growing period. There is a significant correlation between vegetation cover and precipitation and thus, the change in precipitation is an important factor for vegetation variation. The improved agricultural production has resulted in an increase of NDVI in the farmland, and the implementation of large-scale vegetation

  9. Spatiotemporal variations of vegetation cover on the Chinese Loess Plateau (1981―2006): Impacts of climate changes and human activities

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Spatiotemporal variations of Chinese Loess Plateau vegetation cover during 1981-2006 have been investigated using GIMMS and SPOT VGT NDVI data and the cause of vegetation cover changes has been analyzed, considering the climate changes and human activities. Vegetation cover changes on the Loess Plateau have experienced four stages as follows: (1) vegetation cover showed a continued increasing phase during 1981-1989; (2) vegetation cover changes came into a relative steady phase with small fluctuations during 1990-1998; (3) vegetation cover declined rapidly during 1999-2001; and (4) vegetation cover increased rapidly during 2002-2006. The vegetation cover changes of the Loess Plateau show a notable spatial difference. The vegetation cover has obviously increased in the Inner Mongolia and Ningxia plain along the Yellow River and the ecological rehabilitated region of Ordos Plateau, however the vegetation cover evidently decreased in the hilly and gully areas of Loess Plateau, Liupan Mountains region and the northern hillside of Qinling Mountains. The response of NDVI to climate changes varied with different vegetation types. NDVI of sandy land vegetation, grassland and cultivated land show a significant increasing trend, but forest shows a decreasing trend. The results obtained in this study show that the spatiotemporal variations of vegetation cover are the outcome of climate changes and human activities. Temperature is a control factor of the seasonal change of vegetation growth. The increased temperature makes soil drier and unfavors vegetation growth in summer, but it favors vegetation growth in spring and autumn because of a longer growing period. There is a significant correlation between vegetation cover and precipitation and thus, the change in precipitation is an important factor for vegetation variation. The improved agricultural production has resulted in an increase of NDVI in the farmland, and the implementation of large-scale vegetation construction has

  10. Nonlinearities in vegetation functioning

    Science.gov (United States)

    Ceballos-Núñez, Verónika; Müller, Markus; Metzler, Holger; Sierra, Carlos

    2016-04-01

    Given the current drastic changes in climate and atmospheric CO2 concentrations, and the role of vegetation in the global carbon cycle, there is increasing attention to the carbon allocation component in biosphere terrestrial models. Improving the representation of C allocation in models could be the key to having better predictions of the fate of C once it enters the vegetation and is partitioned to C pools of different residence times. C allocation has often been modeled using systems of ordinary differential equations, and it has been hypothesized that most models can be generalized with a specific form of a linear dynamical system. However, several studies have highlighted discrepancies between empirical observations and model predictions, attributing these differences to problems with model structure. Although efforts have been made to compare different models, the outcome of these qualitative assessments has been a conceptual categorization of them. In this contribution, we introduce a new effort to identify the main properties of groups of models by studying their mathematical structure. For this purpose, we performed a literature research of the relevant models of carbon allocation in vegetation and developed a database with their representation in symbolic mathematics. We used the Python package SymPy for symbolic mathematics as a common language and manipulated the models to calculate their Jacobian matrix at fixed points and their eigenvalues, among other mathematical analyses. Our preliminary results show a tendency of inverse proportionality between model complexity and size of time/space scale; complex interactions between the variables controlling carbon allocation in vegetation tend to operate at shorter time/space scales, and vice-versa. Most importantly, we found that although the linear structure is common, other structures with non-linearities have been also proposed. We, therefore, propose a new General Model that can accommodate these

  11. Wave Dissipation by Vegetation

    Science.gov (United States)

    2011-09-01

    Coastal and Hydraulics Engineering Technical Note (CHETN) provides a literature review of wave dissipation by vegetation. INTRODUCTION: Flooding...coastal mangrove forests of Vietnam (Quartel et al. 2007, Mazda et al. 2006, Mazda et al. 1997), salt marshes of the United States (Bradley and...et al. 2007, Mazda et al. 2006, Cooper 2005, Möller and Spencer 2002, Möller et al. 1999). A year-long study by Cooper (2005) found that wave

  12. 黑河中游植被生长季土壤呼吸和净生态系统碳交换量的季节变化%Seasonal Variation of Soil Respiration and Net Ecosystem Carbon Exchange During Vegetation Growing Season in the Middle Reaches of the Heihe River

    Institute of Scientific and Technical Information of China (English)

    孙敏敏; 王旭峰; 马明国; 袁文平; 李香兰

    2016-01-01

    基于涡度相关法和静态箱―气相色谱法的净生态系统碳交换量(net ecosystem exchange,NEE)与土壤呼吸(soil respiration,Rs)速率观测数据,探讨了黑河中游不同土地利用方式下净生态系统碳交换量和土壤呼吸的季节变化,以及土壤呼吸对净生态系统碳交换量的贡献率。结果表明,净生态系统碳交换量和土壤呼吸速率在时间尺度上呈现多峰变化趋势,7月底至8月初达到峰值;在空间尺度上受植被覆盖度的影响,植被稀疏的荒漠、戈壁和沙漠呈现较为一致的变化趋势,土壤呼吸对净生态系统碳交换量的贡献率达20%~68%;而植被密集的玉米地、果园和湿地则呈现较高的季节变异性,土壤呼吸对净生态系统碳交换量的贡献率为10%~21%。土壤呼吸的微小变动可能引起净生态系统碳交换量明显变化。%Objective]The middle reaches of the Heihe River is located in the inland arid region of Northwest China and under the continental central temperate arid climate,this area is low in precipitation, high in evaporation and strong in solar radiation. Such climatic environment conditions nurse a unique type of mosaic distribution of farmlands,orchards,wetlands,wastelands,deserts and gobis. This region of the middle reaches of the Heihe River is a sensitive and ecologically fragile area in the course of environmental evolution. So the study on issues related to net ecosystem carbon exchange(NEE)and soil respiration(Rs) relative to land use is of some extremely important theoretical and practical significance in maintaining ecological balance and promoting sustainable development of the region. However,little information is available in the literature on seasonal and spatial distribution of Rs and NEE in different terrestrial ecosystems in this region;and on contribution of Rs to NEE.[Method]In this study,six different patterns of land use (corn field

  13. Impacts of Colville River dynamics on river navigability near Nuiqsut, Alaska: 1955-present

    Science.gov (United States)

    Whitley, M. A.; Panda, S. K.; Prakash, A.; Brinkman, T. J.

    2016-12-01

    Climate-driven changes in river systems are challenging access to ecosystem services such as access to traditional hunting grounds and other subsistence food sources on the North Slope of Alaska. This work studies the dynamics of the Colville River and assesses the impacts on traditional harvest practices and subsistence travel of the Native community of Nuiqsut. Recent reports from Nuiqsut residents indicate accelerated changes in the environment, limiting river travel and their ability to harvest subsistence food. This study explores how channel migration, gravel bars, and bank erosion have evolved since the 1950s, and their impact on water depth and navigability. In an area of ice-rich permafrost, warmer summer temperatures exacerbate lateral bank erosion, resulting in river siltation. The study focuses on selected key areas south of Nuiqsut that have shown significant change in river geomorphology. Since 1955, some areas proximate to ice wedge exposures show channel migration in excess of 1 km. Panchromatic aerial photography acquired by US Geological Surveys in the mid 1950s, color infrared aerial photography from 1979 and 1982 acquired by the Alaska High Altitude Photography (AHAP) mission, and high resolution satellite images from Digital Globe, Inc. were used in this study. We mapped water, vegetation, and gravel/non-vegetated classes to identify risk areas for river navigability. River bathymetry was also mapped using a multispectral ratio-based water depth retrieval algorithm to identify problem sites for boat travel. Remote sensing products and analyses were validated with field data for mapping risk areas along the river. This study has the potential to be implemented on a larger scale for predictive mapping to aid river navigation. Findings from this study will provide insight whether recent changes are anomalies, or if they are part of a directional trend that will require local adaptation.

  14. Vegetation survey of Four Mile Creek wetlands. [Savannah River Plant

    Energy Technology Data Exchange (ETDEWEB)

    Loehle, C.

    1990-11-01

    A survey of forested wetlands along upper Four Mile Creek was conducted. The region from Road 3 to the creek headwaters was sampled to evaluate the composition of woody and herbaceons plant communities. All sites were found to fall into either the Nyssa sylvatica (Black Gum) -- Persea borbonia (Red Bay) or Nyssa sylvatica -- Acer rubrum (Red Maple) types. These community types are generally species-rich and diverse. Previous studies (Greenwood et al., 1990; Mackey, 1988) demonstrated contaminant stress in areas downslope from the F- and H-Area seepage basins. In the present study there were some indications of contaminant stress. In the wetland near H-Area, shrub basal area, ground cover stratum species richness, and diversity were low. In the area surrounding the F-Area tree kill zone, ground cover stratum cover and shrub basal area were low and ground cover stratum species richness was low. The moderately stressed site at F-Area also showed reduced overstory richness and diversity and reduced ground cover stratum richness. These results could, however, be due to the very high basal area of overstory trees in both stressed F-Area sites that would reduce light availability to understory plants. No threatened or endangered plant species were found in the areas sampled. 40 refs., 4 figs., 8 tabs.

  15. Vegetative Analysis of the Flookplain of the Trinity River, Texas,

    Science.gov (United States)

    1974-09-30

    Celtis laevigata ) and green ash (Fraxinus pensylvanica -associated with decid- uous holly !Ilex decidua), hawthorn ( Crataegus spp.) and honey locust... laevigata ), cedar elm (Ulmus crassifolia) and bush palmetto (Sabal minor) in the bottomlands (Tharp, 1926, 1939, 1952; BraunT950). The soils are...Community 2 were Texas sugar- berry (Celtis laevigata ), box elder and cedar elm (Ulmus crassifolia) (Table 4). American elm (Ulmus americana), swamp

  16. The Vegetation of the Buna River Protected Landscape (Albania

    Directory of Open Access Journals (Sweden)

    Fanelli Giuliano

    2015-12-01

    Full Text Available V članku je opisana vegetacija v zavarovanega območja ob reki Buna. Območje obsega aluvialno ravnino ob spodnjem teku reke Buna, ki predstavlja mejo med Črno goro in Albanijo in karbonatnim hribovjem. Za vegetacijo je značilna visoka β diverziteta (27 zvez in 46 asociacij, še posebej pa mokrišča in suha travišča. V območju smo izločili 1 sekvenco na sipinah, 4 higro sekvence na aluvialni ravnici in 3 ksero serije na karbonatnem masivu. Asociaciji Clematido viticellae-Punicetum granati in Periploco graecae-Alnetum glutinosae sta novo opisani.

  17. Multiscale remote sensing analysis to monitor riparian and upland semiarid vegetation

    Science.gov (United States)

    Nguyen, Uyen

    The health of natural vegetation communities is of concern due to observed changes in the climatic-hydrological regime and land cover changes particularly in arid and semiarid regions. Monitoring vegetation at multi temporal and spatial scales can be the most informative approach for detecting change and inferring causal agents of change and remediation strategies. Riparian communities are tightly linked to annual stream hydrology, ground water elevations and sediment transport. These processes are subject to varying magnitudes of disturbance overtime and are candidates for multi-scale monitoring. My first research objective focused on the response of vegetation in the Upper San Pedro River, Arizona, to reduced base flows and climate change. I addressed the correlation between riparian vegetation and hydro-climate variables during the last three decades in one of the remaining undammed rivers in the southwestern U.S. Its riparian forest is threatened by the diminishing base flows, attributed by different studies either to increases in evapotranspiration (ET) due to conversion of grasslands to mesquite shrublands in the adjacent uplands, or to increased regional groundwater pumping to serve growing populations in surrounding urban areas and or to some interactions of those causes. Landsat 5 imagery was acquired for pre- monsoon period, when riparian trees had leafed out but before the arrival of summer monsoon rains in July. The result has showed Normalized Difference Vegetation Index (NDVI) values from both Landsat and Moderate Resolution Imaging Spectrometer (MODIS) had significant decreases which positively correlated to river flows, which decreased over the study period, and negatively correlated with air temperatures, which have increased by about 1.4°C from 1904 to the present. The predictions from other studies that decreased river flows could negatively impact the riparian forest were supported by this study. The pre-monsoon Normalized Different Vegetation

  18. Síndromes de dispersão de diásporos das espécies de trechos de vegetação ciliar do rio das Pacas, Querência - MT Syndromes of diaspores dispersal of species of riparian vegetation of the river from Pacas, Querência - MT

    Directory of Open Access Journals (Sweden)

    Daniel Stefanello

    2010-03-01

    dispersal in the tropical forest, hence the importance in the conservation of ecological corridors, which allowed the spread of species of a fragment to another. Given the fact, this study aimed to trace the major processes of the seed dispersal of species occurring in the Riparian Evergreen Seasonal Forest areas of the Pacas river, Querência - MT, to identify the main dispersal type. The informations on dispersal syndromes were collected in the field during the sampling the vegetation, wich was divided in strata, according to the eight of the individuals sampled. We identified 69 species, belonged 51 genera and 31 botanic families. The families with the greatest richness were Annonaceae and Fabaceae, which showed the greatest variety syndromes. The zoochory were syndrome the more important, with 86% the total species, followed by anemochory (10%, autochory (3% and barochory (1%. The lower (understory and intermediate (canopy strata have percentage zoochoric species higher than upper stratum (emergente, where the anemochory was the more important. These results demonstrate the strong relationship between the vegetation and animals in the maintenance of plant populations in the riparian environment and the importance of maintaining ecological corridors between forest fragments.

  19. 天山乌鲁木齐河源区3.6 ka BP以来的植被变化和环境变迁:以大西沟剖面为例%Vegetation Changes and Environmental Evolution in the Urumqi River Head,Central Tianshan Mountains Since 3.6 ka BP:a Case Study of Daxigou Profile

    Institute of Scientific and Technical Information of China (English)

    张芸; 孔昭宸; 杨振京; 阎顺; 倪健

    2004-01-01

    A relatively high resolution pollen record and data of loss of ignition (LOI), grain size and susceptibility of the Daxigou profile in the head area of the Urumqi River, central Tianshan Mountains,revealed new information about vegetation changes and environmental evolution since 3.6 ka BP. Results showed that from 3.6 ka BP to present, climate was unstable with multi-changes of warming-cooling and wetting-drying. From ca. 3.6 to 3.2 ka BP, climate was warmer and more humid than today. Climate changed to cooler and drier between ca. 3.2 and 2.0 ka BP, coinciding with a glacier advance in the head area of the Urumqi River. From ca. 2.0 to 1.4 ka BP, climate became warmer and more humid again. From ca. 1.4 to 0.5 ka BP temperature and humidity went on increasing and a period of Climatic Optimum since 3.6 ka BP might occur. A few limnetic hydrophytes pollen are counted for all zones, indicating a freshwater habitat since 3.6 ka BP in this region. Based on synthetically analysis of ecological characteristics and dispersal of spruce pollen, the abundance of Picea is influenced by treeline moving upward, valley wind and glacier ablation. Statistics of charcoal concentration and susceptibility further suggest that fires may have occurred in this region since 0.5 ka BP and the peak value of charcoal might be related to human activities.%天山乌鲁木齐河源区大西沟剖面孢粉鉴定结果表明:在3.6~3.2 ka BP,该区气候较今温暖湿润;在3.2~2.0 ka BP,气候变为寒冷干燥,这一时期乌鲁木齐河源地区曾出现一次冰进;在2.0~1.4 ka BP,气候又转为暖湿;在1.4~0.5 ka BP,出现了3.6 ka BP以来气候最适宜的时期.整个剖面自下而上都有一定量的淡水水生植物出现,这反映了该剖面3 ka BP以来一直处于淡水沼泽的环境中.通过对云杉属生态习性、传播特性等综合分析,认为剖面中的云杉丰值可能与林线上移、山谷风搬运以及冰川退缩等有一定的相关性.通过

  20. Models for calculating phreatic water evaporation on bare and Tamarix-vegetated lands

    Institute of Scientific and Technical Information of China (English)

    HU Shunjun; TIAN Changyan; SONG Yudong; CHEN Xiaobing; LI Yuetan

    2006-01-01

    Groundwater is the main source of water consumption of natural vegetation in arid regions.It is an effective approach to study ecological water demand of natural vegetation by phreatic evaporation.In order to study the ecological water demand of Tarim river basin, based on the observation data of phreatic evaporation on bare lands at the Aksu Water Balance Experimental station from 1989 to 1996, by analyzing the relationship of phreatic evaporation,depth of phreatic surface and evaporation of water,taking the limit rate of phreatic evaporation as the control condition, and based on the objective law that the relation between phreatic evaporation and evaporation of water is nonlinear, we establish models for calculating phreatic evaporation on bare land,which can fully reflect the law of phreatic evaporation in the Tarim river basin. According to the data of depth of phreatic surface and soil moisture when pheratic level decline is caused just by evapotranspiration on Tamarix-vegetated land from 2003 to 2004, we calculate the amount of phreatic evaporation and set up models for calculating phreatic evaporation on Tamarix- vegetated land. Phreatic evaporation on bare land and Tamarix-vegetated land could be transformed each other by a Tamarix vegetation conversion coefficient. The test results show that the calculation accuracy of the models is high and the models are suitable for Tarim river basin.

  1. Mechanisms of vegetation uprooting by flow in alluvial non-cohesive sediment

    Directory of Open Access Journals (Sweden)

    K. Edmaier

    2011-05-01

    Full Text Available The establishment of riparian pioneer vegetation is of crucial importance within river restoration projects. After germination or vegetative reproduction on river bars juvenile plants are often exposed to mortality by uprooting caused by floods. At later stages of root development vegetation uprooting by flow is seen to occur as a consequence of a marked erosion gradually exposing the root system and accordingly reducing the mechanical anchoring. How time scales of flow-induced uprooting do depend on vegetation stages growing in alluvial non-cohesive sediment is currently an open question that we conceptually address in this work. After reviewing vegetation root issues in relation to morphodynamic processes, we then propose two modelling mechanisms (Type I and Type II, respectively concerning the uprooting time scales of early germinated and of mature vegetation. Type I is a purely flow-induced drag mechanism, which causes alone a nearly instantaneous uprooting when exceeding root resistance. Type II arises as a combination of substantial sediment erosion exposing the root system and resulting in a decreased anchoring resistance, eventually degenerating into a Type I mechanism. We support our conceptual models with some preliminary experimental data and discuss the importance of better understanding such mechanisms in order to formulate sounding mathematical models that are suitable to plan and to manage river restoration projects.

  2. Snagging, Clearing, and Shelterbelt for Flood Control, Snake River, Minnesota.

    Science.gov (United States)

    1982-01-01

    Water Quality 8 Water Supply 8 Wildlife Resources 11 Fish 11 Mamals 11 Birds 11 Amphibians and Reptiles 12 Endangered Species 12 Vegetation 12 Land Use...relationships. It is important, especially in an area like the Snake River, to maintain and, if possible, to propagate these ecosystems that represent the...River bottoms rich in bird life, as evidenced by the large number of species that are known to use the area. Amphibians and Reptiles 2.21 The limited

  3. Environmental gradients across wetland vegetation groups in the arid slopes of Western Alborz Mountains, N. Iran

    Directory of Open Access Journals (Sweden)

    Asghar Kamrani

    2011-01-01

    Full Text Available Mountain wetlands are unique ecosystems in the arid southern slopes of Alborz range, the second largest range in Iran. The spatial distribution characteristics of wetland vegetation in the arid region of the Alborz and the main factors affecting their distributional patterns were studied. A classification of vegetation and ecological characteristics were carried out using data extracted from 430 relevés in 90 wetland sites. The data were analyzed using Two Way Indicator Species Analysis (TWINSPAN and detrended correspondence analysis (DCA. The wetland vegetation of Alborz Mountain was classified into four large groups. The first vegetation group was calcareous rich vegetation, mainly distributed in the river banks and characterized by helophytes such as Bolboschoenus affinis as indicator species. The second group was saline transitional vegetation, distributed in the ecotone areas and dominated by Phragmites australis. The third vegetation group is wet meadow vegetation which mainly consists of geophytes, endemic and Irano-Turanian species, distributed in the higher altitudes. This vegetation is mainly characterized by indicator species such as Carex orbicularis, high level concentration of Fe2+ and percentage of organic matter in the soil. The fourth vegetation group is aquatic vegetation, distributed in the lakeshores. The aquatic group species are mainly hydrophytic such as Batrachium trichophyllum. The TWINSPAN vegetation groups could be also recognized in the DCA graphs and ecologically differentiated by ANOVA of studied variables. Four vegetation groups can be differentiated on two first axes of indirect ordination. There is a gradient of pH, EC and organic matter associated with altitude on the DCA diagram. Correlation analysis between the axes of DCA and environmental factors shows that altitude, soil texture and other dependant environmental variables (e.g. pH are the main environmental factors affecting the distribution of wetland

  4. Simulating the Hydrologic Impact of Arundo donax Invasion on the Headwaters of the Nueces River in Texas

    OpenAIRE

    Shailee Jain; Srinivasulu Ale; Clyde L. Munster; R. James Ansley; James R. Kiniry

    2015-01-01

    Arundo donax (hereafter referred to as Arundo), a robust herbaceous plant, has invaded the riparian zones of the Rio Grande River and the rivers of the Texas Hill Country over the last two decades. Arundo was first observed along the Nueces River in central Texas in 1995 by the Nueces River Authority (NRA). It then spread rapidly downstream due to its fast growth rate and availability of streamflow for its consumptive use, and it completely displaced the native vegetation, primarily Panicum v...

  5. Phenolation of vegetable oils

    Directory of Open Access Journals (Sweden)

    ZORAN S. PETROVIĆ

    2011-04-01

    Full Text Available Novel bio-based compounds containing phenols suitable for the syn­thesis of polyurethanes were prepared. The direct alkylation of phenols with different vegetable oils in the presence of superacids (HBF4, triflic acid as ca­talysts was studied. The reaction kinetics was followed by monitoring the de­crease of the double bond content (iodine value with time. In order to under­stand the mechanism of the reaction, phenol was alkylated with model com­pounds. The model compounds containing one internal double bond were 9-oc­tadecene and methyl oleate and those with three double bonds were triolein and high oleic safflower oil (82 % oleic acid. It was shown that the best structures for phenol alkylation are fatty acids with only one double bond (oleic acid. Fatty acids with two double bonds (linoleic acid and three double bonds (lino­lenic acid lead to polymerized oils by a Diels–Alder reaction, and to a lesser extent to phenol alkylated products. The reaction product of direct alkylation of phenol with vegetable oils is a complex mixture of phenol alkylated with poly­merized oil (30–60 %, phenyl esters formed by transesterification of phenol with triglyceride ester bonds (<10 % and unreacted oil (30 %. The phenolated vegetable oils are new aromatic–aliphatic bio-based raw materials suitable for the preparation of polyols (by propoxylation, ethoxylation, Mannich reactions for the preparation of polyurethanes, as intermediates for phenolic resins or as bio-based antioxidants.

  6. Response of Vegetation on Gravel Bars to Management Measures and Floods: Case Study From the Czech Republic

    Directory of Open Access Journals (Sweden)

    Eremiášová Renata

    2014-08-01

    Full Text Available This article investigates response of vegetation on gravel bars to management measures and floods. The management measures consisted of the partial removal of gravel and vegetation cover, and were applied to six gravel bars on the Ostravice River, Czech Republic. Unexpected floods occu-rred in 2010, with the amplitude of 5- to 50-year repetition. Research of vegetation on the gravel bars consisted of vegetation survey before the management works; the monitoring of vegetation development over the following year and the verification of the relationships of species diversity, successional stages and the biotope conditions with the help of multivariate analysis (detrended correspondence analysis. Vegetation on the gravel bars was at different successional stages, and had higher diversity and vegetation cover before the management measures and floods. The mul-tivariate analysis revealed a shift toward initial successional stages with high demand on moisture, temperature and light after both management measures and floods.

  7. Experimental characterization of vegetation uprooting by flow

    Science.gov (United States)

    Edmaier, K.; Crouzy, B.; Perona, P.

    2015-09-01

    We investigate vegetation uprooting by flow for Avena sativa seedlings with stem-to-sediment size ratio close to unity and vanishing obstacle-induced scouring. By inducing parallel riverbed erosion within an experimental flume, we measure the time-to-uprooting in relation to root anchoring and flow drag forces. We link the erosion rate to the uprooting timescales for seedlings with varying mean root length. We show that the process of continuous erosion leading to uprooting resembles that of mechanical fatigue where system collapsing occurs after a given exposure time. By this analogy, we also highlight the nonlinear role of the residual root anchoring versus the flow drag acting on the canopy when uprooting occurs. As a generalization, we propose a framework to extend our results to time-dependent erosion rates, which typically occur for real river hydrographs. Finally, we discuss how the characteristic timescale of plant uprooting by flow erosion suggests that vegetation survival is conditioned by multiple erosion events and their interarrival time.

  8. Vegetation dynamics of the Tanbi Wetland National Park, The Gambia

    Science.gov (United States)

    Ceesay, A.

    2016-12-01

    Changes in mangrove vegetation have been identified as an important indicator of environmental change. The mangroves of the Tanbi Wetland National Park (TWNP) connect the Atlantic coast with the estuary of the River Gambia and as such, play an invaluable role in the agriculture, tourism and fisheries sectors of The Gambia. Our research seeks to understand the long-term changes in the mangrove vegetation to strengthen the formulation of sustainable alternative livelihoods and adaptation strategies to climate change. Mangrove vegetation dynamics was assessed by remote sensing, using decadal Landsat images covering 1973 - 2012. Physicochemical parameters were analyzed during the rainy and dry seasons of The Gambia for correlation with climate data. Our findings indicate that the long-term changes in salinity (24.5 and 35.8ppt) and water temperature (27.6oC and 30.2oC) during the rainy and dry seasons respectively are retarding mangrove growth. Mangrove vegetation cover declined by 6%, while grassland increased by 56.4%. This research concludes that long-term hyper-salinity is the cause for the stunted vegetation and lack of mangrove rejuvenation. We propose that specialized replanting systems such as the use of saplings be adopted instead of the conventional use of propagules. Alternative livelihoods also need to be diversified to support coastal communities.

  9. Relishes: The new pickled vegetables

    Directory of Open Access Journals (Sweden)

    Tepić Aleksandra N.

    2006-01-01

    Full Text Available There have been an increasing interest of consumers for a ide variety of pickled vegetable products worldwide. Regarding the regional vegetable supplies and relatively poor assortment of ready-to-use products, the need to broaden the offer of domestic pickled vegetables at the market came out. In this work recipes for different vegetables, spices and condiments were developed. The best graded samples were analyzed for their main chemical composition (dry matter, proteins, oils and fats, total acidity, total sugars, sucrose, starch, cellulose, pH and energy- values.

  10. Crestridge Vegetation Map [ds211

    Data.gov (United States)

    California Department of Resources — This layer represents vegetation communities in the Department of Fish and Game's Crestridge Ecological Reserve. The County of San Diego, the Conservation Biology...

  11. Changes of Coastal Wetland Ecosystems in the Yellow River Delta and Protection Countermeasures to Them

    OpenAIRE

    Cui, Guangzhou; Zhang, Xuliang; Zhang, Zhaohui; Xu, Zongjun

    2013-01-01

    Coastal wetlands in the Yellow River Delta are typical new wetland ecosystems in warm temperate zone. In recent years, influenced by natural and human factors, these coastal wetlands in the Yellow River Delta have undergone changes of landscape fragmentation, vegetation degradation, pollution, species reduction, and harmful exotic species invasion. These changes have influenced sustainable and healthy development of marine economy of the Yellow River Delta. To protect natural ecological envir...

  12. Fruits and vegetables dehydration

    Science.gov (United States)

    de Ita, A.; Flores, G.; Franco, F.

    2015-01-01

    Dehydration diagrams were determined by means of Differential Thermal Analysis, DTA, and Thermo Gravimetric Analysis, TGA, curves of several simultaneous fruits and vegetables, all under the same conditions. The greater mass loss is associated with water containing in the structure of the investigated materials at low temperature. In poblano chile water is lost in a single step. The banana shows a very sharply two stages, while jicama can be observed although with a little difficulty three stages. The major mass loss occurs in the poblano chile and the lower in banana. The velocity and temperature of dehydration vary within a small range for most materials investigated, except for banana and cactus how are very different.

  13. Response of vegetation to different time-scales drought across China: Spatiotemporal patterns, causes and implications

    Science.gov (United States)

    Zhang, Qiang; Kong, Dongdong; Singh, Vijay P.; Shi, Peijun

    2017-05-01

    Based on Normalized Difference Vegetation Index (NDVI) and Standardized Precipitation Evapotranspiration Index (SPEI), we investigated vegetation response to different time-scales drought across different vegetation types and homogeneous clusters in China, by annual maximum Pearson correlation (Rmax) and the corresponding time-scales of drought. Results showed that: (1) 8 subregions with homogeneous climate-vegetation conditions were identified using Fuzzy C-Means algorithm; (2) SPEI and NDVI's annual Rmax were in significantly positive correlation in most regions of China, indicating that vegetation biomass were influenced mainly by the spatiotemporal characteristics of the water availability. The southeastern Yangtze River basin and the lower Pearl River basin are dominated by abundant precipitation, and vegetation is not sensitive to droughts in these regions. The northeastern Heilongjiang province, the Changbai Mountains and western Sichuan province are characterized by weak NDVI versus SPEI relations, indicating a relatively small effect of drought on vegetation; (3) The effects of annual average water balance, annual average annual precipitation, annual average effective accumulative temperature, and annual average daily sunshine hours on the NDVI versus SPEI correlation show that the annual average water balance is the key factor behind the change of vegetation vigor. It can therefore be concluded that the change of water availability is the key factor behind the change of vegetation activity and biomass. Regional precipitation or water balance was significantly related to the correlation between SPEI and NDVI. Vegetation in the regions with longer sunshine hours is more sensitive to droughts. In general, the sensitivity of grassland to droughts is the largest, followed by the sensitivity of shrubs and forests to droughts.

  14. Sediment transport under the presence and absence of emergent vegetation in a natural alluvial channel from Brazil

    Institute of Scientific and Technical Information of China (English)

    José Ramon Barros Cantalice; Vijay P. Singh; Wagner Luís da Silva Souza

    2016-01-01

    Studies regarding the influence of emergent vegetation on sediment transport are scarce and have mainly focused on flume conditions. To fill this gap and also meet the international need, we aimed to evaluate the influence of emergent vegetation (Echinodorus macrophyllus) on sediment transport of Capibaribe River, Brazil. Bedload and suspended sediment measurements were carried out using the US BLH 84 and US DH 48 samplers, respectively. Measurements of stem diameter, stem spacing and plant density were performed in conjunction with flow and sediment field measurements. Based on our results, 0.45 m s ? 1 was the threshold of mean flow velocity supported by E. macrophyllus under field conditions. This value can be helpful for other rivers with gravel-bed river to armoured layer ratio (AR ¼ D50-surface)/D50-subsurface ¼ 12.50) – natural conditions observed in Capibaribe River – or where the vegetation can provide positive effects, such as increase the bed stability, assist water restoration/rehabilitation and decrease water turbidity. Our results can hopefully be used in engineering practice and ecosystem management. In general, both the drag coefficient and drag force varied inversely and directly with the mean flow velocity and vegetation density, respectively. The vegetation resistance force was inversely proportional to the bedload transport owing to the resistance caused by emergent vegetation. This finding was supported by the clear decoupling between nonvegetated and emergent vegetated conditions indicated by cluster analysis. The study results provided a reasonable understanding of the interaction between emergent vegetation, water flow and sediment transport in the Capibaribe River.&2016 International Research and Training Centre on Erosion and Sedimentation/the World Association

  15. Vegetation survey of Pen Branch and Four Mile Creek wetlands

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    One hundred-fifty plots were recently sampled (vegetational sampling study) at the Savannah River Site (SRS). An extensive characterization of the vascular flora, in four predetermined strata (overstory, Understory, shrub layer, and ground cover), was undertaken to determine dominance, co-dominance, and the importance value (I.V.) of each species. These results will be used by the Savannah River Laboratory (SRL) to evaluate the environmental status of Four Mile Creek, Pen Branch, and two upland pine stands. Objectives of this study were to: Describe in detail the plant communities previously mapped with reference to the topography and drainage, including species of plants present: Examine the successional trends within each sampling area and describe the extent to which current vegetation communities have resulted from specific earlier vegetation disturbances (e.g., logging and grazing); describe in detail the botanical field techniques used to sample the flora; describe the habitat and location of protected and/or rare species of plants; and collect and prepare plant species as herbarium quality specimens. Sampling was conducted at Four Mile Creek and Pen Branch, and in two upland pine plantations of different age growth.

  16. Vegetation survey of Pen Branch and Four Mile Creek wetlands

    Energy Technology Data Exchange (ETDEWEB)

    1992-10-01

    One hundred-fifty plots were recently sampled (vegetational sampling study) at the Savannah River Site (SRS). An extensive characterization of the vascular flora, in four predetermined strata (overstory, Understory, shrub layer, and ground cover), was undertaken to determine dominance, co-dominance, and the importance value (I.V.) of each species. These results will be used by the Savannah River Laboratory (SRL) to evaluate the environmental status of Four Mile Creek, Pen Branch, and two upland pine stands. Objectives of this study were to: Describe in detail the plant communities previously mapped with reference to the topography and drainage, including species of plants present: Examine the successional trends within each sampling area and describe the extent to which current vegetation communities have resulted from specific earlier vegetation disturbances (e.g., logging and grazing); describe in detail the botanical field techniques used to sample the flora; describe the habitat and location of protected and/or rare species of plants; and collect and prepare plant species as herbarium quality specimens. Sampling was conducted at Four Mile Creek and Pen Branch, and in two upland pine plantations of different age growth.

  17. Scales of form roughness on riverbanks with different riparian vegetation

    Science.gov (United States)

    Konsoer, K. M.; Rhoads, B. L.; Best, J.; Langendoen, E. J.; Ursic, M.; Abad, J. D.; Garcia, M. H.

    2013-12-01

    Riverbanks often include topographic irregularities that occur over a range of scales and that are produced by interactions among erosional processes, vegetation, and the geotechnical properties of the banks and floodplains. Irregularity of the bank surface can increase form drag, affecting the overall flow resistance, near-bank shear stresses, and patterns of sediment transport. Understanding how dominant scales of form roughness influence the near-bank flow structure, and thus the shear stress partitioning, is vital for the development of accurate predictive morphodynamic models. In this paper, the scales of bank roughness are examined for two meander bends of a large alluvial river with differing riparian vegetation on the Wabash River near Grayville, Illinois. Detailed measurements of bank topography were obtained using terrestrial LiDAR during low flow events and a multibeam echo sounder (MBES) during bankfull events. These measurements yielded high spatial resolution maps (~5-10 cm) that were used to analyze scales of roughness at different elevations along the banks during both subaerial and subaqueous conditions. The results of these analyses provide insight into the influence of riparian vegetation on form roughness and patterns of near-bank flow structure as documented using acoustic Doppler current profilers (ADCP).

  18. Monitoring phenology of floodplain grassland and herbaceous vegetation with UAV imagery

    NARCIS (Netherlands)

    Van Iersel, W. K.; Straatsma, M. W.; Addink, E. A.; Middelkoop, H.

    2016-01-01

    River restoration projects, which aim at improved flood safety and increased ecological value, have resulted in more heterogeneous vegetation. However, they also resulted in increasing hydraulic roughness, which leads to higher flood water levels during peak discharges. Due to allowance of vegetatio

  19. Toxicología Vegetal

    OpenAIRE

    García Fernández, Antonio Juan

    2010-01-01

    Presentaciones de clase de los temas de Toxicología Vegetal de la licenciatura de Veterinaria de la Universidad de Murcia del curso 2011/12. Presentaciones de Toxicología Vegetal de la asignatura de Toxicología de la Licenciatura de Veterinaria del curso 2011/12

  20. Toxicología Vegetal

    OpenAIRE

    García Fernández, Antonio Juan

    2010-01-01

    Presentaciones de clase de los temas de Toxicología Vegetal de la licenciatura de Veterinaria de la Universidad de Murcia del curso 2011/12. Presentaciones de Toxicología Vegetal de la asignatura de Toxicología de la Licenciatura de Veterinaria del curso 2011/12

  1. RiverFlow2D numerical simulation of flood mitigation solutions in the Ebro River

    Directory of Open Access Journals (Sweden)

    I. Echeverribar

    2017-01-01

    Full Text Available A study of measures oriented to flood mitigation in the mid reach of the Ebro river is presented: elimination of vegetation in the riverbed, use of controlled flooding areas and construction or re-adaptation of levees. The software used is RiverFlow2D which solves the conservative free-surface flow equations with a finite volume method running on GPU. The results are compared with measurements at gauge stations and aerial views. The most effective measure has turned out to be the elimination of vegetation in the riverbed. It is demonstrated that not only the maximum flooded area is narrower but also it reduces the water depth up to 1 m. The other measures have local consequences when the peak discharge is relatively high although they could be useful in case the discharge is lower.

  2. Insights to integrated river management from a geomorphological viewpoint

    Science.gov (United States)

    Valyrakis, Manousos; Liu, Da

    2016-04-01

    In the context of increasing magnitude and frequency of extreme hydrologic events, eco-hydraulic engineers have a dual role of providing novel designs that both help stabilise river systems, as well as help effectively route floodwater safely downstream, though the catchment. One of such soft and green measures commonly used in engineering to protect channel banks and floodplains, is riverbank vegetation. Riverbank vegetation can be of high importance both in preserving the form (morphology) and function (ecology) of our natural as well as engineered river systems. Here the results of an experimental flume study, investigating riverbank hydrodynamics are presented. The effect of different riverbank vegetation densities on flow hydrodynamics across the channel are reported and discussed. Flow diagnostics including mean and turbulent intensity flow profiles along the streamwise and lateral directions, are being assessed via acoustic Doppler velocimetry (ADV) both at the main channel and within the riverbank. The configuration of vegetation elements follows a linear or staggered arrangement as vegetation density is progressively increased. Implications for sediment transport are discussed by considering the change in near-bed shear stresses at the main channel (increasing) and riverbank (decreasing) as the riverbank density increases. As such processes have the potential to affect both the form and function of the river system, the insights from this study are of significant importance to geomorphologists and hydraulic engineers, as well as ecologists.

  3. Spatial Vegetation Data for Effigy Mounds National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — The vegetation spatial database coverage (vegetation map) is a product of the Effigy Mounds National Monument Vegetation Mapping Project, USGS-NPS Vegetation Mapping...

  4. Monitoring Phenology of Floodplain Grassland and Herbaceous Vegetation with Uav Imagery

    Science.gov (United States)

    van Iersel, W. K.; Straatsma, M. W.; Addink, E. A.; Middelkoop, H.

    2016-06-01

    River restoration projects, which aim at improved flood safety and increased ecological value, have resulted in more heterogeneous vegetation. However, they also resulted in increasing hydraulic roughness, which leads to higher flood water levels during peak discharges. Due to allowance of vegetation development and succession, both ecological and hydraulic characteristics of the floodplain change more rapidly over time. Monitoring of floodplain vegetation has become essential to document and evaluate the changing floodplain characteristics and associated functioning. Extraction of characteristics of low vegetation using single-epoch remote sensing data, however, remains challenging. The aim of this study was to (1) evaluate the performance of multi-temporal, high-spatial-resolution UAV imagery for extracting temporal vegetation height profiles of grassland and herbaceous vegetation in floodplains and (2) to assess the relation between height development and NDVI changes. Vegetation height was measured six times during one year in 28 field plots within a single floodplain. UAV true-colour and false-colour imagery of the floodplain were recorded coincidently with each field survey. We found that: (1) the vertical accuracy of UAV normalized digital surface models (nDSMs) is sufficiently high to obtain temporal height profiles of low vegetation over a growing season, (2) vegetation height can be estimated from the time series of nDSMs, with the highest accuracy found for combined imagery from February and November (RMSE = 29-42 cm), (3) temporal relations between NDVI and observed vegetation height show different hysteresis behaviour for grassland and herbaceous vegetation. These results show the high potential of using UAV imagery for increasing grassland and herbaceous vegetation classification accuracy.

  5. MONITORING PHENOLOGY OF FLOODPLAIN GRASSLAND AND HERBACEOUS VEGETATION WITH UAV IMAGERY

    Directory of Open Access Journals (Sweden)

    W. K. van Iersel

    2016-06-01

    Full Text Available River restoration projects, which aim at improved flood safety and increased ecological value, have resulted in more heterogeneous vegetation. However, they also resulted in increasing hydraulic roughness, which leads to higher flood water levels during peak discharges. Due to allowance of vegetation development and succession, both ecological and hydraulic characteristics of the floodplain change more rapidly over time. Monitoring of floodplain vegetation has become essential to document and evaluate the changing floodplain characteristics and associated functioning. Extraction of characteristics of low vegetation using single-epoch remote sensing data, however, remains challenging. The aim of this study was to (1 evaluate the performance of multi-temporal, high-spatial-resolution UAV imagery for extracting temporal vegetation height profiles of grassland and herbaceous vegetation in floodplains and (2 to assess the relation between height development and NDVI changes. Vegetation height was measured six times during one year in 28 field plots within a single floodplain. UAV true-colour and false-colour imagery of the floodplain were recorded coincidently with each field survey. We found that: (1 the vertical accuracy of UAV normalized digital surface models (nDSMs is sufficiently high to obtain temporal height profiles of low vegetation over a growing season, (2 vegetation height can be estimated from the time series of nDSMs, with the highest accuracy found for combined imagery from February and November (RMSE = 29-42 cm, (3 temporal relations between NDVI and observed vegetation height show different hysteresis behaviour for grassland and herbaceous vegetation. These results show the high potential of using UAV imagery for increasing grassland and herbaceous vegetation classification accuracy.

  6. Vegetation Landscape, Ecological Characteristics and Soil Fixation for Riverbank in Taiwan

    Institute of Scientific and Technical Information of China (English)

    CHANG Chunpin; LIN Farching; LIANG Taching; CHEN Yichang

    2007-01-01

    This study is aimed to investigate and analyze the vegetation landscape around Rivers of Hou-lung, Fa-tz, Da-li, Ching-shuei and Gau- ping, and to select the suitable plant species that could be applied for the area of riverbank ecological engineering in Taiwan. Studying the vegetation established the key point and procedure of ecological engineering in the riverside and revetment, to compile and edit the dominant plants' types, life form, propagating method, root systems' characteristics and functions for soil conservation. This research choses three dominant plants for roots strength test. The fitting models of plants pulling resistance(Rp', kg) between plant height (H, cm), diameter near ground (Dn,mm), diameter above ground 100 mm (Da, mm), The research finished the relative abundant, types and cluster analysis of riverbank dominant plants that generalize vegetative distribution and ecological restoration for different river types to apply and manage in Taiwan.

  7. Vegetation line transects of Goose Pasture and Pool No. 1: Clarence Cannon National Wildlife Refuge: Part of Wildlife Management Study – Project 2: Evaluating production of moist soil plants in the Mississippi River Flood Plain and their subsequent use by waterfowl

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Wildlife Management Study - Project No. 2 dated May 15, 1969 was developed to evaluate the production of moist soil food plants in the Mississippi River flood...

  8. Vegetation effects on fish distribution in impounded salt marshes

    Science.gov (United States)

    Stolen, Eric D.; Collazo, Jaime; Percival, H. Franklin

    2009-01-01

    We compared the density and biomass of resident fish in vegetated and unvegetated flooded habitats of impounded salt marshes in the northern Indian River Lagoon (IRL) Estuary of east-central Florida. A 1-m2 throw trap was used to sample fish in randomly located, paired sample plots (n = 198 pairs) over 5 seasons in 7 impoundments. We collected a total of 15 fish taxa, and 88% of the fishes we identified from the samples belonged to three species: Cyprinodon variegatus (Sheepshead Minnow), Gambusia holbrooki (Eastern Mosquitofish), and Poecilia latipinna (Sailfin Molly). Vegetated habitat usually had higher density and biomass of fish. Mean fish density (and 95% confidence interval) for vegetated and unvegetated sites were 8.2 (6.7–9.9) and 2.0 (1.6–2.4) individuals m-2, respectively; mean biomass (and 95%) confidence interval) for vegetated and unvegetated sites were 3.0 (2.5–3.7) and 1.1 (0.9–1.4) g m-2, respectively. We confirmed previous findings that impounded salt marshes of the northern IRL Estuary produce a high standing stock of resident fishes. Seasonal patterns of abundance were consistent with fish moving between vegetated and unvegetated habitat as water levels changed in the estuary. Differences in density, mean size, and species composition of resident fishes between vegetated and unvegetated habitats have important implications for movement of biomass and nutrients out of salt marsh by piscivores (e.g., wading birds and fishes) via a trophic relay.

  9. Interactions among hydrogeomorphology, vegetation, and nutrient biogeochemistry in floodplain ecosystems

    Science.gov (United States)

    Noe, G.B.

    2013-01-01

    Hydrogeomorphic, vegetative, and biogeochemical processes interact in floodplains resulting in great complexity that provides opportunities to better understand linkages among physical and biological processes in ecosystems. Floodplains and their associated river systems are structured by four dimensional gradients of hydrogeomorphology: longitudinal, lateral, vertical, and temporal components. These four dimensions create dynamic hydrologic and geomorphologic mosaics that have a large imprint on the vegetation and nutrient biogeochemistry of floodplains. Plant physiology, population dynamics, community structure, and productivity are all very responsive to floodplain hydrogeomorphology. The strength of this relationship between vegetation and hydrogeomorphology is evident in the use of vegetation as an indicator of hydrogeomorphic processes. However, vegetation also influences hydrogeomorphology by modifying hydraulics and sediment entrainment and deposition that typically stabilize geomorphic patterns. Nitrogen and phosphorus biogeochemistry commonly influence plant productivity and community composition, although productivity is not limited by nutrient availability in all floodplains. Conversely, vegetation influences nutrient biogeochemistry through direct uptake and storage as well as production of organic matter that regulates microbial biogeochemical processes. The biogeochemistries of nitrogen and phosphorus cycling are very sensitive to spatial and temporal variation in hydrogeomorphology, in particular floodplain wetness and sedimentation. The least studied interaction is the direct effect of biogeochemistry on hydrogeomorphology, but the control of nutrient availability over organic matter decomposition and thus soil permeability and elevation is likely important. Biogeochemistry also has the more documented but indirect control of hydrogeomorphology through regulation of plant biomass. In summary, the defining characteristics of floodplain ecosystems

  10. Retrieval of vegetation hydrodynamic parameters from satellite multispectral data

    Science.gov (United States)

    Forzieri, Giovanni; Degetto, Massimo; Righetti, Maurizio; Castelli, Fabio; Preti, Federico

    2013-04-01

    Riparian vegetation plays a crucial role on affecting the floodplain hydraulic roughness, which in turn significantly influences the dynamics of flood waves. This work explores the potential accuracies of retrieving vegetation hydrodynamic parameters through satellite multispectral data. The method is focused on estimation of vegetation height and flexural rigidity for herbaceous patterns and of plant density, tree height, stem diameter, crown base height and crown diameter of high-forest and coppice consociations for arboreal and shrub patterns. The retrieval algorithm performs: (1) classification procedure of riparian corridor; (2) land cover-based Principal Component Analysis of spectral channels; (3) explorative analysis of correlation structure between principal components and biomechanical properties and (4) model identification/estimation/validation for floodplain roughness parameterization. To capture the impacts of stiff/flexible vegetation, a GIS hydrodynamic model has been coupled with a flow resistance external routine that estimates the hydraulic roughness by using simulated water stages and the remote sensing-derived vegetation parameters. The procedure is tested along a 3-km reach of the Avisio river (Trentino Alto Adige, Italy) by comparing extended field surveys and a synchronous SPOT-5 multispectral image acquired on 28/08/2004. Results showed significant correlation values between spectral-derived information and hydrodynamic parameters. Predictive models provided high coefficients of determination, especially for mixed arboreal and shrub land covers. The generated structural parameter maps represent spatially explicit data layers that can be used as inputs to hydrodynamic models to analyze flow resistance effects in different submergence conditions of vegetation. The hydraulic modelling results showed that the new method is able to provide accurate hydraulic output data and to enhance the roughness estimation up to 73% with respect to a

  11. Spatial Vegetation Data for Dinosaur National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This polygon feature class represents vegetation communities mapped at Dinosaur National Monument. The polygons were delineated following guidelines set by the...

  12. Spatial Vegetation Data for Colorado National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — The vegetation units on this map were determined through a series of image processing steps including unsupervised classification, ecological modeling and...

  13. Spatial Vegetation Data for Badlands National Park Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This metadata is for all coverages associated with the vegetation land cover and land use geospatial database for Badlands National Park and surrounding areas. The...

  14. Spatial Vegetation Data for Wupatki National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This metadata is for the vegetation and land-use geo-spatial database for Wupatki National Monument and surrounding areas. The project is authorized as part of the...

  15. Spatial Vegetation Data for Zion National Park Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This metadata is for the vegetation and land-use geo-spatial database for Zion National Park and surrounding areas. The project is authorized as part of the USGS/NPS...

  16. Spatial Vegetation Data for Tuzigoot National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — The vegetation units on this map were determined through the stereoscopic interpretation of aerial photographs supported by field sampling and ecological analysis....

  17. Spatial Vegetation Data for Navajo National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — Vegetation at NAVA was mapped and classified by a combination of field plot data collected in 2005 and photo interpretation from 1:12,000 scale color aerial...

  18. Spatial Vegetation Data for Glacier National Park Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — The geographic information system (GIS) format spatial data set of vegetation for Glacier National Park (GNP) was created by the U.S. Geological Survey...

  19. Spatial Vegetation Data for Hovenweep National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This polygon feature class represents vegetation communities mapped at Hovenweep National Monument. The polygons were generated using guidelines set by the USGS-NPS...

  20. Spatial Vegetation Data for Voyageurs National Park Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — The vegetation spatial database coverage is of Voyageurs National Park and extended environs, covering 156,886 hectares (387,674 acres). Voyageurs National Park...

  1. Northern Hemisphere control of deglacial vegetation changes in the Rufiji uplands (Tanzania)

    Science.gov (United States)

    Bouimetarhan, I.; Dupont, L.; Kuhlmann, H.; Patzold, J.; Prange, M.; Schefuss, E.; Zonneveld, K.

    2015-05-01

    In tropical eastern Africa, vegetation distribution is largely controlled by regional hydrology, which has varied over the past 20 000 years. Therefore, accurate reconstructions of past vegetation and hydrological changes are crucial for a better understanding of climate variability in the tropical southeastern African region. We present high-resolution pollen records from a marine sediment core recovered offshore of the Rufiji River delta. Our data document significant shifts in pollen assemblages during the last deglaciation, identifying, through changes in both upland and lowland vegetation, specific responses of plant communities to atmospheric (precipitation) and coastal (coastal dynamics and sea-level changes) alterations. Specifically, arid conditions reflected by a maximum pollen representation of dry and open vegetation occurred during the Northern Hemisphere cold Heinrich event 1 (H1), suggesting that the expansion of drier upland vegetation was synchronous with cold Northern Hemisphere conditions. This arid period is followed by an interval in which forest and humid woodlands expanded, indicating a hydrologic shift towards more humid conditions. Droughts during H1 and the shift to humid conditions around 14.8 kyr BP in the uplands are consistent with latitudinal shifts of the intertropical convergence zone (ITCZ) driven by high-latitude Northern Hemisphere climatic fluctuations. Additionally, our results show that the lowland vegetation, consisting of well-developed salt marshes and mangroves in a successional pattern typical for vegetation occurring in intertidal habitats, has responded mainly to local coastal dynamics related to marine inundation frequencies and soil salinity in the Rufiji Delta as well as to the local moisture availability. Lowland vegetation shows a substantial expansion of mangrove trees after ~ 14.8 kyr BP, suggesting an increased moisture availability and river runoff in the coastal area. The results of this study highlight the

  2. Northern Hemisphere control of deglacial vegetation changes in the Rufiji uplands (Tanzania

    Directory of Open Access Journals (Sweden)

    I. Bouimetarhan

    2014-09-01

    Full Text Available In tropical Eastern Africa, vegetation distribution is largely controlled by regional hydrology which has varied over the past 20 000 years. Therefore, accurate reconstructions of past vegetation and hydrological changes are crucial to better understand climate variability in the tropical Eastern African region. Through high-resolution pollen records from a marine sediment core recovered offshore the Rufiji River, our data show significant shifts in pollen assemblages during the last deglaciation identifying, through respective changes in both upland and lowland vegetation, specific responses of plant communities to atmospheric (precipitation and coastal (coastal dynamics/sea level changes alterations. Specifically, an interval of maximum pollen representation of dry and open vegetation occurred during the Northern Hemisphere cold Heinrich event 1 (H1 suggesting the expansion of drier upland vegetation under arid conditions. This dry spell is followed by an interval in which forest and humid woodland expanded, indicating a hydrologic shift towards more humid conditions. Droughts during H1 and the return to humid conditions around ~14.8 kyr BP in the uplands are primarily attributed to latitudinal shifts of the Intertropical Convergence Zone (ITCZ driven by high-latitude Northern Hemisphere climatic fluctuations. Additionally, our results show that the lowland vegetation, consisting of a well developed salt marshes and mangroves in a successional pattern typical for vegetation occurring in intertidal habitats, has responded mainly to local coastal dynamics related to marine inundation frequencies and soil salinity in the Rufiji Delta as well as the local moisture availability. Lowland vegetation shows a substantial expansion of mangrove trees after ~14.8 kyr BP suggesting also an increased moisture availability and river runoff in the coastal area. The results of this study highlight the de-coupled climatic and environmental processes to which

  3. Geomorphic and hydrodynamic responses of experimental alluvial channels to rigid vegetation

    Science.gov (United States)

    Bennett, S. J.

    2009-05-01

    Vegetation such as trees and woody debris remains a key component of bank stabilization and stream restoration programs because of the beneficial ecologic and hydraulic effects and attributes it brings to river corridors. Yet few design criteria currently are available to guide the use and application of these activities, and part of this problem may lie in not knowing precisely how river corridors respond to the newly introduced vegetation. Physical experiments provide the unambiguous quantification of the geomorphic, hydraulic, and hydrodynamic responses of alluvial channels to the introduction of vegetation. To this end, a range of physical experiments have been conducted using simulated stands of rigid, emergent vegetation and submerged large woody debris in both fixed- and mobile-bed channels to identify these geomorphic responses to and hydrodynamic effects of the introduced vegetation. Experimental results will focus on flow resistance, secondary flow and meander development, coherent flow structures and turbulent mixing, localized erosion and deposition, and the potential for nutrient retention, all in relation to the size, shape, orientation, and density of managed plantings of vegetation or the placement of large woody debris. These experimental results will be compared to both theory and numerical models, and will be discussed within the context of stream restoration design.

  4. Glacial-interglacial vegetation change in the Zambezi catchment

    Science.gov (United States)

    Dupont, L. M.; Kuhlmann, H.

    2017-01-01

    Changes in the environment are thought to have had strong impact on human evolution. The pollen record of GeoB9311, retrieved offshore of the Zambezi River mouth, indicates glacial-interglacial changes in the vegetation of southern East Africa with enhanced forests in the coastal area during interglacials, more Afromontane forest and ericaceous bushland during glacials and an increase in mopane woodland during the transitional periods. C4 swamps, probably with papyrus, might have spread during the more humid phases of the glacial, while mangroves responded sensitively to changes in sea level. The spread of open ericaceous bushland and Afromontane forest during glacials is found for most of Southern Africa with the exception of the extreme south and southwest regions. In contrast to the western part of the continent, forest and woodland in East Africa did not completely disappear during the glacial. It seems that on a regional scale climatic perturbations of the vegetation are less severe than in West Africa.

  5. CONTRIBUTIONS TO AQUATIC VEGETATION OF ISAC-UZLINA COMPLEX KNOWLEDGE

    Directory of Open Access Journals (Sweden)

    STEFAN NICOLAE

    2004-11-01

    Full Text Available Aquatic vegetation represents an important natural filter for the impurities charge of the Danube river water, constituting a barrier which hinds the polluants entrance in the Black Sea. It is important to mention that the conventional industrial installations, to obtain the treatment objectives of waste waters, use the same physical , chemical and biological principles as that which acts in a natural wet zone. The Isac – Uzlina aquatic complex (Danube Delta Biosphere Reserve was studied and a number of 13 aquatic associations was identified. For every of these, the floristic structure, composition and specific features are also given out. 40 releves of aquatic vegetation from 40 points were used to characterize this aquatic complex.

  6. Relationship between Water and Vegetation in the Ejina Dclta

    Institute of Scientific and Technical Information of China (English)

    YU Jingjie; WANG Ping

    2012-01-01

    Water is the foundation of an arid ecological system, as the quantity and quality of surface water and groundwater determine its structure and function. The study on the relationship between water and ecosystem is the basis of ecosystem protection. Taking the Ejina delta, an extremely arid area located downstream of the Heihe River in northwestern China, as an example, this article gives an overviewe of the study in three aspects: (1) the groundwater table and salinity dynamics and their driving factors, (2) the groundwater depth and salt threshold of natural vegetation ecosystem, and (3) the impact evaluation of ecological flow control on Ejina natural vegetation. The authors point out the importance of the research into the relation between water and ecosystem and its key difficulties and weakness, and put forward strategies for promoting the study processes.

  7. CHARACTERISTICS OF VEGETATION COVER, ROUGHNESS AND ALBEDO DISTRIBUTION OVER CHINA

    Institute of Scientific and Technical Information of China (English)

    张正秋; 周秀骥; 李维亮; 徐兴奎

    2001-01-01

    To build land surface dataset for climate model, with application of remote sensing technique as well as the Geographic Information System (GIS), the data of surface type, roughness and albedo over China in 1997 were retrieved, resolutions being 10 km× 10 km. Based on these data,an analysis is conducted on the geographic distributions and seasonal variations of surface vegetation cover and roughness as well as albedo over China. Results show that surface vegetation cover is mainly located to the south of Yangtze River, in Southwest and Northeast China and sparse vegetation cover is in the Northwest. The variation of land surface cover affects the variations of land surface roughness and albedo. High albedo occurred in the north of Xinjiang Autonomous Region, the north of Northeast China and the Qinghai-Xizang Plateau in winter, in correspondence with the location of snow cover.For most part of China, surface roughness decreases and albedo increases in winter, while the roughness increases and the albedo decreases in summer, which could mainly result from land surface cover (snow cover and vegetation cover) and soil moisture changes. This shows that the geographic distribution and seasonal variation of the albedo are alnost opposite to those of the roughness, in agreement with theoretical results. Temporally, the amplitude of surface roughness change is quite small in comparison with the roughness itself.

  8. RAPID SEPARATION OF ACTINIDES AND RADIOSTRONTIUM IN VEGETATION SAMPLES

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, S.

    2010-06-01

    A new rapid method for the determination of actinides and radiostrontium in vegetation samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used in emergency response situations or for routine analysis. The actinides in vegetation method utilizes a rapid sodium hydroxide fusion method, a lanthanum fluoride matrix removal step, and a streamlined column separation process with stacked TEVA, TRU and DGA Resin cartridges. Lanthanum was separated rapidly and effectively from Am and Cm on DGA Resin. Alpha emitters are prepared using rare earth microprecipitation for counting by alpha spectrometry. The purified {sup 90}Sr fractions are mounted directly on planchets and counted by gas flow proportional counting. The method showed high chemical recoveries and effective removal of interferences. The actinide and {sup 90}Sr in vegetation sample analysis can be performed in less than 8 h with excellent quality for emergency samples. The rapid fusion technique is a rugged sample digestion method that ensures that any refractory actinide particles or vegetation residue after furnace heating is effectively digested.

  9. Vegetation - McKenzie Preserve [ds703

    Data.gov (United States)

    California Department of Resources — The California Native Plant Society (CNPS) Vegetation Program produced a vegetation map and classification for approximately 11,600 acres primarily within Millerton...

  10. Developing an algorithm for enhancement of a digital terrain model for a densely vegetated floodplain wetland

    Science.gov (United States)

    Mirosław-Świątek, Dorota; Szporak-Wasilewska, Sylwia; Michałowski, Robert; Kardel, Ignacy; Grygoruk, Mateusz

    2016-07-01

    Airborne laser scanning survey data were conducted with a scanning density of 4 points/m2 to accurately map the surface of a unique central European complex of wetlands: the lower Biebrza River valley (Poland). A method to correct a degrading effect of vegetation (so-called "vegetation effect") on digital terrain models (DTMs) was applied utilizing remotely sensed images, real-time kinematic global positioning system elevation measurements, topographical surveys, and vegetation height measurements. Geographic object-based image analysis (GEOBIA) was performed to map vegetation within the study area that was used as categories from which vegetation height information was derived for the DTM correction. The final DTM was compared with a model obtained, where additional correction of the "vegetation effect" was neglected. A comparison between corrected and uncorrected DTMs demonstrated the importance of accurate topography through a simple presentation of the discrepancies arising in features of the flood using various DTM products. An overall map classification accuracy of 80% was attained with the use of GEOBIA. Correction factors developed for various types of the vegetation reached values from 0.08 up to 0.92 m and were dependent on the vegetation type.

  11. The vegetation and floristics of the Letaba exclosures, Kruger National Park, South Africa

    Directory of Open Access Journals (Sweden)

    Frances Siebert

    2010-03-01

    Full Text Available The construction of exclosures along two of the most important rivers in the Kruger National Park was done to investigate how patterns of spatial and temporal heterogeneity of the riparian zone is affected by fire, flood and herbivory. To assist this research programme, vegetation surveys were conducted within exclosures along the Letaba River to classify and map the vegetation of the area. The history and experimental design of the Letaba exclosures are similar to that of the Nkhuhlu exclosures along the Sabie River, which is directly related to questions surrounding elephant management. The main difference between the Nkhuhlu and Letaba exclosures is local heterogeneity, since the latter lies within the Mopaneveld, which is floristically and physiognomically much more homogenous than the vegetation of the southern Kruger National Park. Nevertheless, four plant communities, eight sub-communities and six variants were recognised and mapped for the Letaba exclosures. The vegetation description was done in relation to prevailing soil forms, differences in species richness, diversity and community structure, and therefore should serve as a basis for further detailed and broad-based botanical studies. Vegetation mapping was done to sub-community level and, where possible, to variant level. As expected in Mopaneveld vegetation, the plant communities could broadly be related to soil types, although smaller-scale variations correspond to soil moisture availability because the Mopaneveld is considered ‘event-driven’, especially in the herbaceous layer.Conservation implications: Floristic surveying and vegetation mapping of a long-term monitoring site, such as the Letaba exclosures, is seen as a baseline inventory to assist natural resource management. Linking mapping units to biodiversity strengthens the understanding needed to maintain biodiversity in all its natural facets and fluxes.

  12. Abrupt vegetation transitions characterise long-term Amazonian peatland development

    Science.gov (United States)

    Roucoux, K. H.; Baker, T. R.; Gosling, W. D.; Honorio Coronado, E.; Jones, T. D.; Lahteenoja, O.; Lawson, I. T.

    2012-04-01

    Recent investigations of wetlands in western Amazonia have revealed the presence of extensive peatlands with peat deposits of up to 8 m-thick developing under a variety of vegetation types (Lähteenoja et al. 2012). Estimated to cover 150,000 km2 (Schulman et al. 1999), these peatlands make a valuable contribution to landscape and biological diversity and represent globally important carbon stores. In order to understand the processes leading to peat formation, and the sensitivity of these environments to future climatic change, it is necessary to understand their long-term history. The extent to which peatland vegetation changes over time, the stability of particular communities, the controls on transitions between vegetation types and how these factors relate to the accumulation of organic matter are not yet known. We report the first attempt to establish the long-term (millennial scale) vegetation history of a recently-described peatland site: Quistococha, a palm swamp, or aguajal, close to Iquitos in northern Peru. The vegetation is dominated by Mauritia flexuosa and Mauritiella armata and occupies a basin which is thought to be an abandoned channel of the River Amazon. We obtained a 4 m-long peat sequence from the deepest part of the basin. AMS-radiocarbon dating yielded a maximum age of 2,212 cal yr BP for the base of the peat, giving an average accumulation rate of 18 cm per century. Below the peat are 2 m of uniform, largely inorganic pale grey clays of lacustrine origin, which are underlain by an unknown thickness of inorganic sandy-silty clay of fluvial origin. Pollen analysis, carried out at c. 88-year intervals, shows the last 2,212 years to be characterised by the development of at least four distinct vegetation communities, with peat accumulating throughout. The main phases were: (1) Formation of Cyperaceae (sedge) fen coincident with peat initiation; (2) A short-lived phase of local Mauritia/Mauritiella development; (3) Development of mixed wet

  13. Canadian National Vegetation Classification (CNVC)

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The mandate of the CNVC is to comprehensively classify and describe natural and semi-natural Canadian vegetation in an ecologically meaningful manner. The...

  14. Vegetation - Lassen Foothills [ds564

    Data.gov (United States)

    California Department of Resources — In 2007 Aerial Information Systems, Inc. (AIS) was contracted by the California Native Plant Society (CNPS) to produce a vegetation map for approximately 100,000...

  15. Sustainable land and water management of River Oases along the Tarim River

    Science.gov (United States)

    Disse, Markus

    2016-05-01

    The Tarim Basin in Xinjiang province in northwest China is characterized by a hyper arid climate. Climate change and a strong increase in agricultural land use are major challenges for sustainable water management. The largest competition for water resources exists between irrigated fields and natural riparian vegetation, which is dependent on seasonal flooding of the Tarim River. In addition to numerous water management measures implemented by the Chinese government, the Sino-German project SuMaRiO (Sustainable Management of River Oases along the Tarim River) provided a decision support system based on ecosystem services for the Chinese stakeholders. This tool will help to implement sustainable land and water management measures in the next 5-year plan.

  16. Historical analysis of riparian vegetation change in response to shifting management objectives on the Middle Rio Grande

    Science.gov (United States)

    Petrakis, Roy; van Leeuwen, Willem J.D.; Villarreal, Miguel; Tashjian, Paul; Dello Russo, Regina; Scott, Christopher A.

    2017-01-01

    Riparian ecosystems are valuable to the ecological and human communities that depend on them. Over the past century, they have been subject to shifting management practices to maximize human use and ecosystem services, creating a complex relationship between water policy, management, and the natural ecosystem. This has necessitated research on the spatial and temporal dynamics of riparian vegetation change. The San Acacia Reach of the Middle Rio Grande has experienced multiple management and river flow fluctuations, resulting in threats to its riparian and aquatic ecosystems. This research uses remote sensing data, GIS, a review of management decisions, and an assessment of climate to both quantify how riparian vegetation has been altered over time and provide interpretations of the relationships between riparian change and shifting climate and management objectives. This research focused on four management phases from 1935 to 2014, each highlighting different management practices and climate-driven river patterns, providing unique opportunities to observe a direct relationship between river management, climate, and riparian response. Overall, we believe that management practices coupled with reduced surface river-flows with limited overbank flooding influenced the compositional and spatial patterns of vegetation, including possibly increasing non-native vegetation coverage. However, recent restoration efforts have begun to reduce non-native vegetation coverage.

  17. River Morphology and River Channel Changes

    Institute of Scientific and Technical Information of China (English)

    CHANG Howard H

    2008-01-01

    River morphology has been a subject of great challenge to scientists and engineers who recognize that any effort with regard to river engineering must be based on a proper understanding of the morphological features involved and the responses to the imposed changes. In this paper,an overview of river morphology is presented from the geomorphic viewpoint. Included in the scope are the regime concept, river channel classification, thresholds in river morphology, and geomor-phic analysis of river responses. Analytical approach to river morphology based on the physical principles for the hydraulics of flow and sediment transport processes is also presented. The appli-cation of analytical river morphology is demonstrated by an example. Modeling is the modern tech-nique to determine both short-term and long-term river channel responses to any change in the en-vironment. The physical foundation of fluvial process-response must be applied in formatting a mathematical model. A brief introduction of the mathematical model FLUVIAL-12 is described.

  18. Análise fitossociológica de um remanescente de vegetação na microbacia do Córrego Criminoso (Bacia do Rio Taquari, Coxim, MS, Brasil: subsídios para a recomposição da vegetação Phytosociological analysis of a vegetation remnant in the Córrego Criminoso Basin (Taquari River Basin, Coxim District, Mato Grosso do Sul, Brazil: data for vegetation recovery studies

    Directory of Open Access Journals (Sweden)

    Adriana Maria Güntzel

    2011-09-01

    Full Text Available O objetivo deste estudo foi realizar a análise florística e fitossociológica preliminar em um remanescente de vegetação na área de entorno do Córrego Criminoso, visando subsidiar futuros projetos de recomposição da vegetação. A área total do remanescente foi determinada com o auxílio de GPS e dos programas Pathfinder e Autocad. Amostragens de indivíduos com CAP maior ou igual a 20 cm foram realizadas em 20 parcelas de 300 m² distribuídas na área. Foram encontradas 26 famílias botânicas contendo 36 gêneros e 49 espécies. A família Leguminosae foi a mais rica em espécies, seguida da família Annonaceae. A espécie Xylopia aromatica foi a mais freqüente, apresentando valores de IVI e IVC de 99,77 e 85,73, respectivamente. Observou-se que mais de 50% das espécies presentes na área são pioneiras ou secundárias, sendo cinco consideradas típicas de matas ciliares: Tapirira guianenses, Cecropia pachystachya, Terminalia argentea, Ocotea pulchellae e Luehea grandiflora. O remanescente de vegetação do entorno do Córrego Criminoso encontra-se fortemente degradado, necessitando de ações de manejo específicos nos fragmentos vegetados e nas áreas destituídas de vegetação, cujas recomendações são propostas.The aim of this study was to complete a preliminary, floristic, phytosociological analyses of a vegetation remnant in the Criminoso Stream Basin, in order to provide data for future projects focusing on vegetation recovery. The total area of the remnant was determined using a GPS and the software Pathfinder and Autocad. Samples of individuals larger or equal to 20 cm CBH were made in 20 quadrats that were 300 m². Thirty-six genera and 49 species, within 26 botanical families, were found. The family Leguminosae was the richest in species, followed by the Annonaceae. Xylopia aromatica was the most frequent species, presenting values of IVI and IVC of 99.77 and 85.73, respectively. More than 50% of the species present

  19. MARKETING WINTER VEGETABLES FROM MEXICO

    OpenAIRE

    Calvin, Linda; Barrios, Veronica

    1999-01-01

    The North American winter-vegetable industry is highly integrated, with Mexican production supplying a large part of U.S. winter consumption needs. Imports from Mexico undergo a rigorous inspection procedure before entering the United States. In addition to Mexican firms, many U.S. firms are also involved in sourcing winter vegetables from Mexico. To compete well, both U.S. and Mexican firms must adapt to the changing market pressures, which reward firms that can source from many locations to...

  20. Effects of Climate Change on Normalized Difference Vegetation Index Based on the Multiple Analysis of Standardized Precipitation Evapotranspiration Index Methods in the Lancang River Basin%基于逐月标准化降水蒸散指数的多尺度方法分析气候变化对澜沧江流域归一化植被指数的影响

    Institute of Scientific and Technical Information of China (English)

    刘世梁; 田韫钰; 安南南; 赵海迪; 董世魁

    2015-01-01

    基于澜沧江流域10个气象站点1951~2012年的日降水资料的逐月标准化降水蒸散指数(SPEI)值、各站1998~2012年流域的归一化植被指数(NDVI)值,利用 SPEI 以及趋势分析法,多尺度分析了澜沧江流域干旱发生的时间和强度演变特征以及上中下游NDVI时间变化特征,探讨了气候变化对植被变化的影响,并对NDVI与SPEI的变化进行了相关性分析。结果表明,不同站点和不同时间尺度的SPEI值均呈现出干旱化逐年加强的线性趋势,上游相对于中下游干旱态势较轻,且时间尺度越大,干旱波动趋势越明显;在季节尺度上,夏、秋、冬的SPEI值均呈下降趋势,其中冬季干旱最为严重;15年来澜沧江流域各区域年平均NDVI总体表现为先降低后增加,总体植被状况得到改善,其中下游较明显。从年际变化看,对于流域的不同区域,NDVI与不同尺度的SPEI的相关性和滞后性有较大差异,年代际之间的响应规律也不同,中下游的SPEI对同年NDVI的响应比较敏感,而上游则表现出明显的滞后性。说明 NDVI 对 SPEI 的响应比较敏感,干旱程度的变化在一定程度上影响着流域的植被状况,SPEI是影响NDVI的因素之一。%The characteristics of drought variations at different timescales in the Lancang River basin from 1951 to 2012 were studied using a new drought index (standardized precipitation evapotranspiration index, SPEI). The authors calculated this level from daily precipitation data at 10 meteorological stations. Furthermore, the authors used a time series (1998–2012) data set of the normalized difference vegetation index (NDVI) and trend analysis to analyze the inter-annual variation in the valley of the Lancang River and explore the relationship between NDVI and SPEI. The results show that the SPEI values at different sites and time scales showed a significant increased trend to drought, but the

  1. SRS 2010 Vegetation Inventory GeoStatistical Mapping Results for Custom Reaction Intensity and Total Dead Fuels.

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Lloyd A. [Leading Solutions, LLC.; Paresol, Bernard [U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Portland, OR.

    2014-09-01

    This report of the geostatistical analysis results of the fire fuels response variables, custom reaction intensity and total dead fuels is but a part of an SRS 2010 vegetation inventory project. For detailed description of project, theory and background including sample design, methods, and results please refer to USDA Forest Service Savannah River Site internal report “SRS 2010 Vegetation Inventory GeoStatistical Mapping Report”, (Edwards & Parresol 2013).

  2. Morphological and vegetation changes on tidal flats of the Amazon Coast during the last 5000 cal. yr BP

    OpenAIRE

    2013-01-01

    The analysis of morphology, sedimentary facies, palynology, carbon and nitrogen isotopes, C/N ratio and radiocarbon data from tidal flats sediments influenced by the Amazon River indicates that vegetation development during the last 5000 cal. yr BP was controlled by morphological changes associated with marine and fluvial process. The proximal portion of the tidal flat corresponds to abandoned channels surrounded by terrest rial vegetation since 5280–5160 cal. yr BP. Du...

  3. Estimating Vegetation Height and Bare-Earth Topography from SRTM Data using Fourier Spectral Decomposition

    Science.gov (United States)

    Gangodagamage, C.; Liu, D.; Alsdorf, D.

    2010-12-01

    In this study, LiDAR vegetation topography (bare-earth + vegetation height), LiDAR bare-earth topography, the National Elevation Data (NED) set, and Shuttle Radar Terrain Mission (SRTM) measurements are used to develop a statistical model to explore the possibility of extracting vegetation height measurements and accurate high resolution bare-earth topography from SRTM data. The key innovation is to obtain the statistical signature of the vegetation height measurements in the Fourier domain by taking advantage of the well-known linearity in additive properties of the Fourier transform. We demonstrate that the power-law relationship, P(k) α k^(-β), as shown by the bare-earth topography, breaks down approximately at a cross-over wavenumber, k=k_c, due to the vegetation height effect using four different topographic and vegetation study locations in the United States. We document that the vegetation effect mainly dominates the high-frequency contents of the vegetation topography from 2-180 m, 1-60 m, and 1-70 m for the South Fork Eel River, California; Flathead Lake, Montana; and Tenderfoot Creek, Montana, LiDAR data, respectively, and from 1-240 m for 30 m SRTM data for the Jesup, Georgia site. Finally, we demonstrate our ability to obtain a high resolution bare-earth topography with RMSE of 9.6 m, 2.2 m, and 2.9 m and vegetation height with RMSE of 11.0 m (11% error), 4.5 m (12% error), and 1.6 m (8% error) for LiDAR data study sites, whereas for the SRTM data, bare-earth topography and vegetation height are obtained with RMSE values of 5.4 m and 3.1 m, respectively, for the Jesup site. Model Vegetation height

  4. Hydraulic, Vegetation and Water Quality Characteristics of Heavily Vegetated Groundwater-Fed Ditches in a Riparian Peatland in Northern Germany

    Science.gov (United States)

    Scholz, M.; Olson, M. S.; Trepel, M.

    2003-12-01

    The Environmental Ministry of Schleswig-Holstein (Northern Germany) has implemented a novel peatland management strategy in order to use the high nutrient retention potential of degenerated wetlands and peatlands, and to improve the habitat conditions at the same time. The effect of raised water levels and passive land use management on hydraulic properties and water quality of heavily vegetated and groundwater-fed ditches at one nationally important wetland case study at the Eider River valley was investigated. Most ditches in the Eider River valley were small and overgrown. The flow properties of selected ditches were regularly assessed at different discharge levels during different vegetation cover periods. The hydraulic residence is predominantly a function of the ditch geometry and overall obstruction cover including the presence of macrophytes. Vegetation cover and other hydraulic obstructions such as accumulated silt and organic debris slow down the hydraulic residence time and lead to a change in the water quality along the ditch. Experimental results were evaluated to get more realistic values for total bed-roughness and pollution loading under different hydraulic flow regimes. The total-roughness Km values of both vegetated and excavated ditch stretches were about 1 and 10, respectively. However, Km is actually a crude "fudge factor" depending predominantly on the hydraulic radius rather than on the total-roughness. This is in contrast to the theory presented in the literature. The biochemical oxygen demand and nutrient concentrations of 24 ditches were analyzed. Mean biochemical oxygen demand, ammonia, nitrite, nitrate and ortho-phosphate concentrations were 6.0 (+/-2.74), 0.2 (+/-0.44), 0.0 (+/-0.02), 1.6 (+/-2.04) and 0.0 (+/-0.02) mg/L, respectively. Elevated biochemical oxygen demand and nitrate concentrations for upstream ditch cross-sections were apparent.

  5. Distributions of landslides, vegetation, and related sediment yields during typhoon events in northwestern Taiwan

    Science.gov (United States)

    Chen, Chi-Wen; Chen, Hongey; Oguchi, Takashi

    2016-11-01

    This study examined landslides caused by typhoon events in the upstream area of the Tao-Cheng River in northwestern Taiwan during a 13-year period, 1996 to 2008. Data from six typhoon events were compiled to analyze the relevant characteristics of landslides, vegetation, and changes in sediment discharge with particulate carbon in rivers in this area. The landslide ratio, the ratio of the landslide area to the total study area, was determined to be between 0.60% and 1.29%, and a high new generation ratio and low reactivated ratio of landslides were noted. Analysis of different bands of satellite images taken over a 10-year period disclosed that the Normalized Difference Vegetation Index (NDVI) in the upstream area of the Tao-Cheng River ranged from 0.47 to 0.63 before typhoon events and from 0.38 to 0.46 after typhoon events. The low landslide ratio and high new generation ratio in this area indicated that sporadic landslides tend to occur in new areas and do not have a great impact on vegetation conditions. Thus, the decrease in NDVI after typhoon events was caused by the seasonal effect with withering of vegetation. On the other hand, landslides in this area tend to occur on nonforest land because of the interventions of external forces, such as human developments and reclamation. Geological materials produced by landslides and vegetation flushed by heavy rainfall during typhoon periods have a great effect on the amount of sediment discharge and particulate carbon discharge in the rivers. Furthermore, during typhoon periods, the amount of accumulated rainfall has a greater impact than the peak rainfall intensity on the increase of sediment and particulate carbon in rivers and on the decrease in the NDVI. Analysis of the particulate carbon from the rivers in this area revealed that in the rainy season, high strength and accumulated rainfall will lead to more sediment discharge and particulate carbon discharge in rivers. However, the particulate carbon is limited

  6. Evaluating the Vegetation Recovery in the Damage Area of Wenchuan Earthquake Using MODIS Data

    Directory of Open Access Journals (Sweden)

    Wei-Guo Jiang

    2015-07-01

    Full Text Available The catastrophic 8.0 Richter magnitude earthquake that occurred on 12 May 2008 in Wenchuan, China caused extensive damage to vegetation due to widespread landslides and debris flows. In the past five years, the Chinese government has implemented a series of measures to restore the vegetation in the severely afflicted area. How is the vegetation recovering? It is necessary and important to evaluate the vegetation recovery effect in earthquake-stricken areas. Based on MODIS NDVI data from 2005 to 2013, the vegetation damage area was extracted by the quantified threshold detection method. The vegetation recovery rate after five years following the earthquake was evaluated with respect to counties, altitude, fault zones, earthquake intensity, soil texture and vegetation types, and assessed over time. We have proposed a new method to obtain the threshold with vegetation damage quantitatively, and have concluded that: (1 The threshold with vegetation damage was 13.47%, and 62.09% of the field points were located in the extracted damaged area; (2 The total  vegetation damage area was 475,688 ha, which accounts for 14.34% of the study area and was primarily distributed in the central fault zone, the southwest mountainous areas and along rivers in the Midwest region of the study area; (3 Vegetation recovery in the damaged area was better in the northeast regions of the study area, and in the western portion of the Wenchuan-Maoxian fracture; vegetation recovery was better with increasing altitude; there is no obvious relationship between clay content in the topsoil and vegetation recovery; (4 Meadows recovered best and the worst recovery was in mixed coniferous broad-leaved forest; (5 81,338 ha of vegetation in the damage area is currently undergoing degradation and the main vegetation types in the degradation area are coniferous forest (31.39% and scrub (34.17%; (6 From 2009 to 2013, 41% has been restored to the level before the earthquake, 9% has not

  7. Restoration of hard mast species for wildlife in Missouri using precocious flowering oak in the Missouri River floodplain, USA

    Science.gov (United States)

    B. C. Grossman; M. A. Gold; Daniel C. Dey

    2003-01-01

    Increased planting of hard mast oak species in the Lower Missouri River floodplain is critical as natural regeneration of oak along the Upper Mississippi and Lower Missouri Rivers has been limited following major flood events in 1993 and 1995. Traditional planting methods have limited success due to frequent flood events, competition from faster growing vegetation and...

  8. Reproduction, growth, and migration of fishes in a regulated lowland tributary: potential recruitment to the River Meuse

    NARCIS (Netherlands)

    Pollux, B.J.A.; Korosi, A.; Verberk, W.C.E.P.; Pollux, P.M.J.; Velde, G. van der

    2006-01-01

    Many European rivers are characterized by a canalized main channel, steep stony embankments, the absence of aquatic vegetation, regulated flow dynamics, reduced hydrological connectivity to the floodplains and a lack of spawning and nursery areas for many fish species. In such regulated rivers, trib

  9. Reproduction, growth and migration of fishes in a regulated lowland tributary: Potential recruitment to the River Meuse

    NARCIS (Netherlands)

    Pollux, B.J.A.; Korosi, A.; Verberk, W.C.E.P.; Pollux, P.M.J.; van der Velde, G.

    2006-01-01

    Many European rivers are characterized by a canalized main channel, steep stony embankments, the absence of aquatic vegetation, regulated flow dynamics, reduced hydrological connectivity to the floodplains and a lack of spawning and nursery areas for many fish species. In such regulated rivers, trib

  10. Quantification of exchangeable and non-exchangeable organically bound tritium (OBT) in vegetation.

    Science.gov (United States)

    Kim, S B; Korolevych, V

    2013-04-01

    The objective of this study is to quantify the relative amounts of exchangeable organically bound tritium (OBT) and non-exchangeable OBT in various vegetables. A garden plot at Perch Lake, where tritium levels are slightly elevated due to releases of tritium from a nearby nuclear waste management area and Chalk River Laboratories (CRL) operations, was used to cultivate a variety of vegetables. Five different kinds of vegetables (lettuce, cabbage, tomato, radish and beet) were studied. Exchangeable OBT behaves like tritium in tissue free water in living organisms and, based on past measurements, accounts for about 20% of the total tritium in dehydrated organic materials. In this study, the percentage of the exchangeable OBT was determined to range from 20% to 57% and was found to depend on the type of vegetables as well as the sequence of the plants exposure to HTO. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  11. Aircraft MSS data registration and vegetation classification of wetland change detection

    Science.gov (United States)

    Christensen, E.J.; Jensen, J.R.; Ramsey, Elijah W.; Mackey, H.E.

    1988-01-01

    Portions of the Savannah River floodplain swamp were evaluated for vegetation change using high resolution (5a??6 m) aircraft multispectral scanner (MSS) data. Image distortion from aircraft movement prevented precise image-to-image registration in some areas. However, when small scenes were used (200-250 ha), a first-order linear transformation provided registration accuracies of less than or equal to one pixel. A larger area was registered using a piecewise linear method. Five major wetland classes were identified and evaluated for change. Phenological differences and the variable distribution of vegetation limited wetland type discrimination. Using unsupervised methods and ground-collected vegetation data, overall classification accuracies ranged from 84 per cent to 87 per cent for each scene. Results suggest that high-resolution aircraft MSS data can be precisely registered, if small areas are used, and that wetland vegetation change can be accurately detected and monitored.

  12. [Responses of vegetation changes to climatic variations in Panxi area based on the MODIS multispectral data].

    Science.gov (United States)

    Shao, Huai-Yong; Wu, Jin-Hui; Liu, Meng; Yang, Wu-Nian

    2014-01-01

    It is an important research area to quantitatively studying the relationship between global climatic change and vegetation change based on the remote sensing technology. Panxi area is the ecological barrier of the upper reaches of the Yangtze River, and it is essential for the stability of the ecological environment of Sichuan as well as that of the whole China. The present article analyzes the vegetation change in 2001-2008 and the relationship between vegetation change and climatic variations of Panxi area, based on MODIS multispectral data and meteorological data. The results indicate that NDVI is positively correlated with temperature and precipitation. The precipitation is the major factor that affects the change of vegetation in the Panxi region and the trend of NDVI is similar with autumn precipitation; while at the same time the influence of climate has a one-month-time-lag.

  13. 中全新世黄河流域耕地格局重建及对原生植被的影响%Reconstruction of cultivated land during mid-Holocene in the middle and lower reaches of Yellow River and human impact on vegetations

    Institute of Scientific and Technical Information of China (English)

    HOU Guangliang; LAI Zhongping; XIAO Jingyi; E Chongyi

    2012-01-01

    @@%Yangshao culture is the most important mid-Holocene Neolithic culture in the Yellow River catchment,and thus,a study on the impact of human activities on the environment is important.In the current study,the distribution pattern of the cultivated land in late Yangshao culture is reconstructed using GIS tool and site domain analysis (SDA).The results show that the cultivated land during 5.5-5.0 ka BP was mainly distributed in the Weihe River valley,Luohe River valley,northwestern Henan Plain,Fenhe River valley and eastern Gansu region,especially concentrated in the Xi'an-Baoji line of the Weihe River valley.At that time,at least 37,000 km2 of lands were reclaimed in the middle and lower reaches of the Yellow River,and 132,000 km2 of lands were affected by agricultural activities.Human activities had become the driving force of land use/land coverage.Charcoal records indicate that the ancestors of Yangshao culture burnt forests for reclamation,leading to the decrease of arbor pollen at 5 ka BP in core areas of the Yangshao culture.The areas that were significantly affected by human activities accounted for 3.2% of the Yangshao culture influenced area,while the moderately affected areas accounted for 20.1% of Yangshao culture influenced area.Meanwhile,92% of the land areas on the edge and outside of the Yangshao culture influenced area were not affected by human activities.The arbor pollen in these areas did not decrease until 4.0 ka BP.

  14. Qingjiang River Developer

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    THE 400-kilometer Qingjiang River, second tributary of the Yangtze River in Hubei Province, has a drainage area of 17,000 square kilometers. Its advantageous natural conditions have made it a key water power development project.

  15. Illinois River NWFR HMP

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Illinois River National Wildlife and Fish Refuges Complex stretches along 124 miles of the Illinois River in west central Illinois. The Complex includes three...

  16. Allegheny County Major Rivers

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — This dataset contains locations of major rivers that flow through Allegheny County. These shapes have been taken from the Hydrology dataset. The Ohio River,...

  17. Iowa's Sovereign Meandered Rivers

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — This data set depicts Iowa's Meandered Rivers. These rivers are deemed sovereign land & therefore require any person wishing to conduct construction activities...

  18. Coupled hydrogeomorphic and woody-seedling responses to controlled flood releases in a dryland river

    Science.gov (United States)

    Wilcox, Andrew C.; Shafroth, Patrick B.

    2013-01-01

    Interactions among flow, geomorphic processes, and riparian vegetation can strongly influence both channel form and vegetation communities. To investigate such interactions, we took advantage of a series of dam-managed flood releases that were designed in part to maintain a native riparian woodland system on a sand-bed, dryland river, the Bill Williams River, Arizona, USA. Our resulting multiyear flow experiment examined differential mortality among native and nonnative riparian seedlings, associated flood hydraulics and geomorphic changes, and the temporal evolution of feedbacks among vegetation, channel form, and hydraulics. We found that floods produced geomorphic and vegetation responses that varied with distance downstream of a dam, with scour and associated seedling mortality closer to the dam and aggradation and burial-induced mortality in a downstream reach. We also observed significantly greater mortality among nonnative tamarisk (Tamarix) seedlings than among native willow (Salix gooddingii) seedlings, reflecting the greater first-year growth of willow relative to tamarisk. When vegetation was small early in our study period, the effects of vegetation on flood hydraulics and on mediating flood-induced channel change were minimal. Vegetation growth in subsequent years resulted in stronger feedbacks, such that vegetation's stabilizing effect on bars and its drag effect on flow progressively increased, muting the geomorphic effects of a larger flood release. These observations suggest that the effectiveness of floods in producing geomorphic and ecological changes varies not only as a function of flood magnitude and duration, but also of antecedent vegetation density and size.

  19. 21 CFR 73.260 - Vegetable juice.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Vegetable juice. 73.260 Section 73.260 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.260 Vegetable juice. (a) Identity. (1) The color additive vegetable juice is prepared either by expressing the juice from mature varieties of fresh, edible vegetables...

  20. The Multi - vitamin Nutrient Fresh Vegetable Juice

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ In the Tenth Five- Year Plan period, an important strategy for food industry is to develop fruit vegetable freshening and processing industry. Now,the consumable demand for vegetables turns to fresh,convenient, nutritious, safe and dean ones, while semi-processed vegetables and mixed fresh vegetable juices will meet this market demand exactly.