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Sample records for extensive vegetative cover

  1. Exploring an extensive dataset to establish woody vegetation cover and composition in Kruger National Park for the late 1980s

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    Gregory A. Kiker

    2014-02-01

    Full Text Available Woody plant cover and species composition play an important role in defining the type and function of savanna ecosystems. Approximately 2000 sites in the Kruger National Park (KNP were surveyed by F.J. Venter over a period from 1985 to 1989, recording vegetation, soil and topological characteristics. At each of these sites (approximately 20 m × 20 m each, woody vegetation cover and species were recorded using a rapid, Braun-Blanquet classification for three height classes: shrub (0.75 m – 2.50 m, brush (2.50 m – 5.50 m and tree (> 5.50 m. The objective of this study was to re-analyse the vegetation component of the field data, with a specific focus to provide a spatially explicit, height-differentiated, benchmark dataset in terms of species occurrence, species richness and structural canopy cover. Overall, 145 different woody species were recorded in the dataset out of the 458 species documented to occur in the park. The dataset describes a woody layer dominated by a relatively small number of widely occurring species, as 24 of the most common woody species accounted for all woody species found on over 80% of all sites. The less common woody species (101 were each recorded on 20 sites or less. Species richness varied from 12 to 1 species per site. Structural canopy cover averaged 9.34%, 8.16% and 2.89% for shrub, brush and tree cover, respectively. The dataset provides a useful benchmark for woody species distribution in KNP and can be used to explore woody species and height class distributions, as well as comparison with more recent or future woody vegetation surveys.Conservation implications: The results provided evidence that large-scale, woody vegetation surveys conducted along roads offer useful ecosystem level information. However, such an approach fails to pick up less common species. The data presented here provided a useful snapshot of KNP woody vegetation structure and composition and could provide excellent opportunities for

  2. Stochastic models of cover class dynamics. [remote sensing of vegetation

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    Barringer, T. H.; Robinson, V. B.

    1981-01-01

    Investigations related to satellite remote sensing of vegetation have been concerned with questions of signature identification and extension, cover inventory accuracy, and change detection and monitoring. Attention is given to models of ecological succession, present directions in successional modeling and analysis, nondynamic spatial models, issues in the analysis of spatial data, and aspects of spatial modeling. Issues in time-series analysis are considered along with dynamic spatial models, and problems of model specification and identification.

  3. Landscape Level Analyses of Vegetation Cover in Northern Alaska

    Science.gov (United States)

    Botting, T.; Hollister, R. D.

    2013-12-01

    Many International Tundra Experiment (ITEX) studies have been conducted to identify vegetation changes due to warming. However, knowledge gaps remain. For example, most of these studies are conducted at the plot level, not the landscape level, potentially masking larger scale impacts of climate change. An Arctic Systems Science (ARCSS) grid was established in Atqasuk, Alaska and Barrow, Alaska in the mid 1990's. In 2010, approximately 100 untreated vegetation plots were implemented at each grid site. These vegetation plots are 1 meter squared, spaced 100 meters apart, and span 1 kilometer squared. Each vegetation plot represents 100 square meters along the grid. This project will focus on how vegetation cover has changed at the landscape level, using the point frame method, from 2010 to 2013. Preliminary data analysis indicates that in Atqasuk, graminoids, deciduous shrubs, and evergreen shrubs show increased cover, while little change has occurred with bryophytes, forbs and lichens. In Barrow, graminoids, lichens and forbs have shown an increase in cover, while little change has occurred with bryophytes and deciduous shrubs. At both sites, graminoids represent the greatest increase in cover of all growth forms analyzed. This study will be the foundation for later work, with the purpose of predicting what ARCSS grid vegetation community compositions will be in the future. These expectations will be based on anticipated warming data from ITEX passively warmed vegetation plots. This will be the first time that ITEX vegetation warming research is applied to landscape level research in Barrow and Atqasuk.

  4. 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.

  5. Estimation of vegetation cover resilience from satellite time series

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    T. Simoniello

    2008-07-01

    Full Text Available Resilience is a fundamental concept for understanding vegetation as a dynamic component of the climate system. It expresses the ability of ecosystems to tolerate disturbances and to recover their initial state. Recovery times are basic parameters of the vegetation's response to forcing and, therefore, are essential for describing realistic vegetation within dynamical models. Healthy vegetation tends to rapidly recover from shock and to persist in growth and expansion. On the contrary, climatic and anthropic stress can reduce resilience thus favouring persistent decrease in vegetation activity.

    In order to characterize resilience, we analyzed the time series 1982–2003 of 8 km GIMMS AVHRR-NDVI maps of the Italian territory. Persistence probability of negative and positive trends was estimated according to the vegetation cover class, altitude, and climate. Generally, mean recovery times from negative trends were shorter than those estimated for positive trends, as expected for vegetation of healthy status. Some signatures of inefficient resilience were found in high-level mountainous areas and in the Mediterranean sub-tropical ones. This analysis was refined by aggregating pixels according to phenology. This multitemporal clustering synthesized information on vegetation cover, climate, and orography rather well. The consequent persistence estimations confirmed and detailed hints obtained from the previous analyses. Under the same climatic regime, different vegetation resilience levels were found. In particular, within the Mediterranean sub-tropical climate, clustering was able to identify features with different persistence levels in areas that are liable to different levels of anthropic pressure. Moreover, it was capable of enhancing reduced vegetation resilience also in the southern areas under Warm Temperate sub-continental climate. The general consistency of the obtained results showed that, with the help of suited analysis

  6. Vegetation type classification and vegetation cover percentage estimation in urban green zone using pleiades imagery

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    Trisakti, Bambang

    2017-01-01

    Open green space in the urban area has aims to maintain the availability of land as a water catchment area, creating aspects of urban planning through a balance between the natural environment and the built environment that are useful for the public needs. Local governments have to make the green zone plan map and monitor the green space changes in their territory. Medium and high resolution satellite imageries have been widely utilized to map and monitor the changes of vegetation cover as an indicator of green space area. This paper describes the use of pleaides imagery to classify vegetation types and estimate vegetation cover percentage in the green zone. Vegetation cover was mapped using a combination of NDVI and blue band. Furthermore, vegetation types in the green space were classified using unsupervised and supervised (ISODATA and MLEN) methods. Vegetation types in the study area were divided into sparse vegetation, low-medium vegetation and medium-high vegetation. The classification accuracies were 97.9% and 98.9% for unsupervised and supervised method respectively. The vegetation cover percentage was determined by calculating the ratio between the vegetation type area and the green zone area. These information are useful to support green zone management activities.

  7. Modeling Microwave Emission from Short Vegetation-Covered Surfaces

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    Yanhui Xie

    2015-10-01

    Full Text Available Owing to the temporal and spatial variability of the emissivity spectra, problems remain in the interpretation and application of satellite passive microwave data over vegetation-covered surfaces. The commonly used microwave land emissivity model, developed by Weng et al. (2001 and implemented into the community radiative transfer model (CRTM, treats vegetation-covered surfaces as a three-layer medium. This simplification comes at the cost of accuracy. In this study, to reduce bias in the modeling of microwave emissions from short vegetation-covered surfaces, two modifications are made. First, vegetation was considered as a multilayered medium including leaves and stems to simulate volumetric absorption and scattering. The results suggest that the calculated brightness temperatures well agree with field experiments under different incidence angles for low soil moisture and sparse crop cover. On the other hand, large errors from the measurements are found for high soil moisture content and dense crop cover. Second, the advanced integral equation model (AIEM was also used to improve the simulation of reflectivity from rough soil surfaces. Comparisons with field experimental data show that the determination coefficient between the calculated and measured brightness temperatures significantly increased and the root-mean-square errors remarkably decreased. The average improvement using the proposed approach is about 80% and 59% in accuracy for the vertical and horizontal polarization, respectively.

  8. Changes in vegetation cover and composition in the Swedish mountain region.

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    Hedenås, Henrik; Christensen, Pernilla; Svensson, Johan

    2016-08-01

    Climate change, higher levels of natural resource demands, and changing land use will likely lead to changes in vegetation configuration in the mountain regions. The aim of this study was to determine if the vegetation cover and composition have changed in the Swedish region of the Scandinavian Mountain Range, based on data from the long-term landscape biodiversity monitoring program NILS (National Inventory of Landscapes in Sweden). Habitat type and vegetation cover were assessed in 1740 systematically distributed permanent field plots grouped into 145 sample units across the mountain range. Horvitz-Thompson estimations were used to estimate the present areal extension of the alpine and the mountain birch forest areas of the mountain range, the cover of trees, shrubs, and plants, and the composition of the bottom layer vegetation. We employed the data from two subsequent 5-year monitoring periods, 2003-2007 and 2008-2012, to determine if there have been any changes in these characteristics. We found that the extension of the alpine and the mountain birch forest areas has not changed between the inventory phases. However, the total tree canopy cover increased in the alpine area, the cover of graminoids and dwarf shrubs and the total cover of field vegetation increased in both the alpine area and the mountain birch forest, the bryophytes decreased in the alpine area, and the foliose lichens decreased in the mountain birch forest. The observed changes in vegetation cover and composition, as assessed by systematic data in a national and regional monitoring scheme, can validate the results of local studies, experimental studies, and models. Through benchmark assessments, monitoring data also contributes to governmental policies and land-management strategies as well as to directed cause and effect analyses.

  9. Vegetated land cover near residence is associated with ...

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    Abstract Background: Greater exposure to urban green spaces has been linked to reduced risks of depression, cardiovascular disease, diabetes and premature death. Alleviation of chronic stress is a hypothesized pathway to improved health. Previous studies linked chronic stress with biomarker-based measures of physiological dysregulation known as allostatic load. This study aimed to assess the relationship between vegetated land cover near residences and allostatic load. Methods: This cross-sectional population-based study involved 204 adult residents of the Durham-Chapel Hill, North Carolina metropolitan area. Exposure was quantified using high-resolution metrics of trees and herbaceous vegetation within 500 m of each residence derived from the U.S. Environmental Protection Agency’s EnviroAtlas land cover dataset. Eighteen biomarkers of immune, neuroendocrine, and metabolic functions were measured in serum or saliva samples. Allostatic load was defined as a sum of biomarker values dichotomized at specific percentiles of sample distribution. Regression analysis was conducted using generalized additive models with two-dimensional spline smoothing function of geographic coordinates, weighted measures of vegetated land cover allowing decay of effects with distance, and geographic and demographic covariates. Results: An inter-quartile range increase in distance-weighted vegetated land cover was associated with 37% (46%; 27%) reduced allostatic load; significantly

  10. Vegetative cover for low level radioactive waste sites

    Energy Technology Data Exchange (ETDEWEB)

    Salvo, S. Keith (USDA Soil Conservation Service, Raleigh, NC (United States))

    1994-06-01

    Low level radioactive waste (LLRW), hazardous, and mixed waste disposal sites normally require some form of plant material to prevent erosion of the soil cover cap. Waste disposal sites are closed and capped in a complex scientific manner to minimize water infiltration and percolation down into the waste material. Turf type grasses are normally used as the principal vegetative cover for most sites. Consequently, the sites require periodic mowing and other expensive annual maintenance practices. The purpose of this 5 year study was to evaluate alternative plant material for use on LLRW sites that can be quickly and easily established and economically maintained, retards water infiltration, provides maximum year-round evapotranspiration, is ecologically acceptable and does not harm the closure cap.The results of the study suggest that two species of bamboo (Phyllostachys bissetii and Phyllostachys rubromarginata) could be utilized to quickly establish a long lived, low maintenance, final vegetative cover for the waste sites.

  11. Texture classification of vegetation cover in high altitude wetlands zone

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    Wentao, Zou; Bingfang, Wu; Hongbo, Ju; Hua, Liu

    2014-03-01

    The aim of this study was to investigate the utility of datasets composed of texture measures and other features for the classification of vegetation cover, specifically wetlands. QUEST decision tree classifier was applied to a SPOT-5 image sub-scene covering the typical wetlands area in Three River Sources region in Qinghai province, China. The dataset used for the classification comprised of: (1) spectral data and the components of principal component analysis; (2) texture measures derived from pixel basis; (3) DEM and other ancillary data covering the research area. Image textures is an important characteristic of remote sensing images; it can represent spatial variations with spectral brightness in digital numbers. When the spectral information is not enough to separate the different land covers, the texture information can be used to increase the classification accuracy. The texture measures used in this study were calculated from GLCM (Gray level Co-occurrence Matrix); eight frequently used measures were chosen to conduct the classification procedure. The results showed that variance, mean and entropy calculated by GLCM with a 9*9 size window were effective in distinguishing different vegetation types in wetlands zone. The overall accuracy of this method was 84.19% and the Kappa coefficient was 0.8261. The result indicated that the introduction of texture measures can improve the overall accuracy by 12.05% and the overall kappa coefficient by 0.1407 compared with the result using spectral and ancillary data.

  12. Extensive, strategic assessment of southeast Alaska's vegetative resources.

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    Willem W.S. van Hees; Bert R. Mead

    2005-01-01

    Effective natural resources management requires knowledge of the character of resources and of interactions between resource components. Estimates of forest and other vegetation resources are presented to provide managers with information about the character of the resource. Slightly less than half (48%) of southeast Alaska has some type of forest land cover, about 29...

  13. ATTITUDES OF VEGETABLE FARMERS TOWARDS PUBLIC AGRICULTURAL EXTENSION SERVICES

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    Tala Qtaishat

    2012-01-01

    Full Text Available Among vegetable farmers in Jordan, there are conflicting attitudes towards the extension activities provided by the public sector. Some farmers accept and adopt the recommendations of these activities; on the other hand, some people are not satisfied and consider these activities a waste of time for both the farmers and the government. This situation has serious impacts on the quality, duration and efficiency of the extension activities provided by government related agencies. Also, the situation will end in providing low-quality agricultural extension services to the farmers or providing these services in a non-productive manner. The actual attitudes of vegetable farmers towards Public Agricultural Extension Services (PAES in the Dear Alla Area of Jordan were investigated in this study. A total of 80 vegetable farmers were selected for the study. A questionnaire consisting of two main parts was used for data collection; the first part was related to personal and socio-economic characteristics of the sample individuals. The second part was related to extension activities. A five-point Likert-type scale was used as an instrument to gather primary data. The farmers rated their attitudes toward Public Agricultural Extension Services (PAES through 10 statements related carefully to the Public Agricultural Extension Services. Data analysis was done in two sections, consisting of data description and data inferential analysis. The results of the study revealed that the farmers’ overall attitude towards the public agricultural extension activities was negative. The farmers’ attitudes according to age, experience, educational level and frequency and type of contact with public extension services were also negative. The negative attitude of the participant farmers towards the Public Agricultural Extension Services means that the farmers were not satisfied with these services. Identifying the sources and types of public extension programs, the

  14. Estimation of Soil Moisture Under Vegetation Cover at Multiple Frequencies

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    Jadghuber, Thomas; Hajnsek, Irena; Weiß, Thomas; Papathanassiou, Konstantinos P.

    2015-04-01

    Soil moisture under vegetation cover was estimated by a polarimetric, iterative, generalized, hybrid decomposition and inversion approach at multiple frequencies (X-, C- and L-band). Therefore the algorithm, originally designed for longer wavelength (L-band), was adapted to deal with the short wavelength scattering scenarios of X- and C-band. The Integral Equation Method (IEM) was incorporated together with a pedo-transfer function of Dobson et al. to account for the peculiarities of short wavelength scattering at X- and C-band. DLR's F-SAR system acquired fully polarimetric SAR data in X-, C- and L-band over the Wallerfing test site in Lower Bavaria, Germany in 2014. Simultaneously, soil and vegetation measurements were conducted on different agricultural test fields. The results indicate a spatially continuous inversion of soil moisture in all three frequencies (inversion rates >92%), mainly due to the careful adaption of the vegetation volume removal including a physical constraining of the decomposition algorithm. However, for X- and C-band the inversion results reveal moisture pattern inconsistencies and in some cases an incorrectly high inversion of soil moisture at X-band. The validation with in situ measurements states a stable performance of 2.1- 7.6vol.% at L-band for the entire growing period. At C- and X-band a reliable performance of 3.7-13.4vol.% in RMSE can only be achieved after distinct filtering (X- band) leading to a loss of almost 60% in spatial inversion rate. Hence, a robust inversion for soil moisture estimation under vegetation cover can only be conducted at L-band due to a constant availability of the soil signal in contrast to higher frequencies (X- and C-band).

  15. Evaluation of vegetation cover using the normalized difference vegetation index (NDVI

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    Gabriela Camargos Lima

    2013-08-01

    Full Text Available Soil loss by water erosion is the main cause of soil degradation in Brazil. However, erosion can be reduced by the presence of vegetation. The Normalized Difference Vegetation Index (NDVI makes it possible to identify the vegetative vigor of crops or natural vegetation which facilities the identification of areas with vegetation covers. This information is very important in identifying the phenomena which might be occurring in a particular area, especially those related to soil degradation by water erosion. Thus, the aim of this work was to assess the canopy cover by using NDVI, checking the image accuracy using the Coverage Index (CI based on the Stocking method, in the Sub-basin of Posses, which belongs to the Cantareira System, located in the Extrema municipality, Minas Gerais, Brazil. Landsat-5 TM images were used. The sub-basin of Posses was very altered in comparison to the surrounding areas. The NDVI technique proved to be a suitable tool to assess the uses that occur in the sub-basin of Posses, as validated by the Stocking methodology. The map derived from NDVI allowed the geographic distribution of different land uses to be observed and allowed for the identification of critical areas in relation to vegetation cover as well. This finding can be used to optimize efforts to recover and protect soil in areas with bare soil and degraded pasture, in order to reduce environmental degradation. The CI has not exceeded 40% for land use classes that occur in the majority of the sub-basin (91%, except in areas of woody vegetation.

  16. Decoupling factors affecting plant diversity and cover on extensive green roofs.

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    MacIvor, J Scott; Margolis, Liat; Puncher, Curtis L; Carver Matthews, Benjamin J

    2013-11-30

    Supplemental irrigation systems are often specified on green roofs to ensure plant cover and growth, both important components of green roof performance and aesthetics. Properties of the growing media environment too can alter the assemblage of plant species able to thrive. In this study we determine how plant cover, above ground biomass and species diversity are influenced by irrigation and growing media. Grass and forb vegetative cover and biomass were significantly greater in organic based growing media but there was no effect of supplemental irrigation, with two warm season grasses dominating in those treatments receiving no supplemental irrigation. On the other hand, plant diversity declined without irrigation in organic media, and having no irrigation in inorganic growing media resulted in almost a complete loss of cover. Sedum biomass was less in inorganic growing media treatments and species dominance shifted when growing media organic content increased. Our results demonstrate that supplemental irrigation is required to maintain plant diversity on an extensive green roof, but not necessarily plant cover or biomass. These results provide evidence that planting extensive green roofs with a mix of plant species can ensure the survival of some species; maintaining cover and biomass when supplemental irrigation is turned off to conserve water, or during extreme drought.

  17. 488-D Ash Basin Vegetative Cover Treatibility Study

    Energy Technology Data Exchange (ETDEWEB)

    Barton, Christopher; Marx, Don; Blake, John; Adriano, Domy; Koo, Bon-Jun; Czapka, Stephen

    2003-01-01

    The 488-D Ash Basin is an unlined containment basin that received ash and coal reject material from the operation of a powerhouse at the USDOE's Savannah River Site, SC. They pyretic nature of the coal rejects has resulted in the formation of acidic drainage (AD), which has contributed to groundwater deterioration and threatens biota in down gradient wetlands. Establishment of a vegetative cover was examined as a remedial alternative for reducing AD generation within this system by enhanced utilization of rainwater and subsequent non-point source water pollution control. The low nutrient content, high acidity, and high salinity of the basin material, however, was deleterious to plant survivability. As such, studies to identify suitable plant species and potential adaptations, and pretreatment techniques in the form of amendments, tilling, and/or chemical stabilization were needed. A randomized block design consisting of three subsurface treatments (blocks) and five duplicated surface amendments (treatments) was developed. One hundred inoculated pine trees were planted on each plot. Herbaceous species were also planted on half of the plots in duplicated 1-m2 beds. After two growing seasons, deep ripping, subsurface amendments and surface covers were shown to be essential for the successful establishment of vegetation on the basin. This is the final report of the study.

  18. Land Cover Vegetation Changes and Hydrology in Central Texas

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    Banta, J. R.; Slattery, R.

    2013-12-01

    Encroachment of woody vegetation into traditional savanna grassland ecosystems in central Texas has largely been attributed to land use practices of settlers, most notably overgrazing and fire suppression. Implementing changes in land cover vegetation (removing the woody vegetation and allowing native grasses to reestablish in the area, commonly referred to as brush management), could potentially change the hydrology in a watershed. The U.S. Geological Survey, in cooperation with several local, State, and Federal agencies, studied the hydrologic effects of ashe juniper (Juniperus ashei) removal as a brush management conservation practice in the Honey Creek State Natural Area in Comal County, Tex. Two adjacent watersheds of 104 and 159 hectares were used in a paired study. Rainfall, streamflow, evapotranspiration (Bowen ratio method), and water quality data were collected in both watersheds. Using a hydrologic mass balance approach, rainfall was allocated to surface-water runoff, evapotranspiration, and potential groundwater recharge. Groundwater recharge was not directly measured, but estimated as the residual of the hydrologic mass balance. After hydrologic data were collected in both watersheds for 3 years, approximately 80 percent of the woody vegetation (ashe juniper) was selectively removed from the 159 hectare watershed (treatment watershed). Brush management was not implemented in the other (reference) watershed. Hydrologic data were collected in both watersheds for six years after brush management implementation. The resulting data were examined for differences in the hydrologic budget between the reference and treatment watersheds as well as between pre- and post-brush management periods to assess effects of the treatment. Results indicate there are differences in the hydrologic budget and water quality between the reference and treatment watersheds, as well as between pre- and post-brush management periods.

  19. EnviroAtlas - Cleveland, OH - 15m Riparian Buffer Vegetated Cover

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    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. In this community, vegetated cover is defined as Trees & Forest,...

  20. EnviroAtlas - New York, NY - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. In this community, vegetated cover is defined as Trees & Forest...

  1. EnviroAtlas - Cleveland, OH - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. In this community, vegetated cover is defined as Trees & Forest,...

  2. EnviroAtlas - Minneapolis/St. Paul, MN - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. In this community, vegetated cover is defined as Trees and Forest,...

  3. EnviroAtlas - New York, NY - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. In this community, vegetated cover is defined as Trees & Forest...

  4. EnviroAtlas - Minneapolis/St. Paul, MN - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. In this community, vegetated cover is defined as Trees and Forest,...

  5. Quantifying regional vegetation cover variability in North China during the Holocene: implications for climate feedback.

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    Guo Liu

    Full Text Available Validating model simulations of vegetation-climate feedback needs information not only on changes in past vegetation types as reconstructed by palynologists, but also on other proxies such as vegetation cover. We present here a quantitative regional vegetation cover reconstruction for North China during the Holocene. The reconstruction was based on 15 high-quality lake sediment profiles selected from 55 published sites in North China, along with their modern remote sensing vegetation index. We used the surface soil pollen percentage to build three pollen-vegetation cover transfer models, and used lake surface sediment pollen data to validate their accuracy. Our results showed that vegetation cover in North China increased slightly before its maximum at 6.5 cal ka BP and has since declined significantly. The vegetation decline since 6.5 cal ka BP has likely induced a regional albedo change and aerosol increase. Further comparison with paleoclimate and paleovegetation dynamics in South China reproduced the regional cooling effect of vegetation cover decline in North China modelled in previous work. Our discussion demonstrates that, instead of reconstructing vegetation type from a single site, reconstructing quantitative regional vegetation cover could offer a broader understanding of regional vegetation-climate feedback.

  6. Quantifying regional vegetation cover variability in North China during the Holocene: implications for climate feedback.

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    Liu, Guo; Yin, Yi; Liu, Hongyan; Hao, Qian

    2013-01-01

    Validating model simulations of vegetation-climate feedback needs information not only on changes in past vegetation types as reconstructed by palynologists, but also on other proxies such as vegetation cover. We present here a quantitative regional vegetation cover reconstruction for North China during the Holocene. The reconstruction was based on 15 high-quality lake sediment profiles selected from 55 published sites in North China, along with their modern remote sensing vegetation index. We used the surface soil pollen percentage to build three pollen-vegetation cover transfer models, and used lake surface sediment pollen data to validate their accuracy. Our results showed that vegetation cover in North China increased slightly before its maximum at 6.5 cal ka BP and has since declined significantly. The vegetation decline since 6.5 cal ka BP has likely induced a regional albedo change and aerosol increase. Further comparison with paleoclimate and paleovegetation dynamics in South China reproduced the regional cooling effect of vegetation cover decline in North China modelled in previous work. Our discussion demonstrates that, instead of reconstructing vegetation type from a single site, reconstructing quantitative regional vegetation cover could offer a broader understanding of regional vegetation-climate feedback.

  7. [Diversity and stability of arthropod community in peach orchard under effects of ground cover vegetation].

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    Jiang, Jie-xian; Wan, Nian-feng; Ji, Xiang-yun; Dan, Jia-gui

    2011-09-01

    A comparative study was conducted on the arthropod community in peach orchards with and without ground cover vegetation. In the orchard with ground cover vegetation, the individuals of beneficial, neutral, and phytophagous arthropods were 1.48, 1.84 and 0.64 times of those in the orchard without ground cover vegetation, respectively, but the total number of arthropods had no significant difference with that in the orchard without ground cover vegetation. The species richness, Shannon's diversity, and Pielou's evenness index of the arthropods in the orchard with ground cover vegetation were 83.733 +/- 4.932, 4.966 +/- 0.110, and 0.795 +/- 0.014, respectively, being significantly higher than those in the orchard without ground cover vegetation, whereas the Berger-Parker's dominance index was 0.135 +/- 0.012, being significantly lower than that (0.184 +/- 0.018) in the orchard without ground cover vegetation. There were no significant differences in the stability indices S/N and Sd/Sp between the two orchards, but the Nn/Np, Nd/Np, and Sn/Sp in the orchard with ground cover vegetation were 0.883 +/- 0.123. 1714 +/- 0.683, and 0.781 +/- 0.040, respectively, being significantly higher than those in the orchard without ground cover vegetation. Pearson's correlation analysis indicated that in the orchard with ground cover vegetation, the Shannon's diversity index was significantly negatively correlated with Nd/Np, Sd/Sp, and S/N but had no significant correlations with Nn/Np and Sn/Sp, whereas in the orchard without ground cover vegetation, the diversity index was significantly positively correlated with Nn/Np and Nd/Np and had no significant correlations with Sd/Sp, Sn/Sp, and S/N.

  8. Cover Crop Chart: An Intuitive Educational Resource for Extension Professionals

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    Liebig, Mark A.; Johnson, Holly; Archer, David; Hendrickson, John; Nichols, Kristine; Schmer, Marty; Tanaka, Don

    2013-01-01

    Interest in cover crops by agricultural producers has increased the need for information regarding the suitability of crops for addressing different production and natural resource goals. To help address this need, staff at the USDA-ARS Northern Great Plains Research Laboratory developed a decision aid called the Cover Crop Chart (CCC). Visually…

  9. Electromagnetic wave scattering from vegetation (Potato) and vegetation covered soil moisture for remote sensing

    Science.gov (United States)

    Singh, Keshev

    In the country with limited resources, where the nutrition level of the population has to be maintained under inhospitable situation, the potato has a special value as food. Therefore efforts should be made for improvement and spreading the cultivation of this important crop. It demands an effective program that may provide information about potato growing areas and the growth conditions. Remote sensing has been acknowledged to be a valuable source of spatially comprehensive and temporally repeatable information of crop covered soil moisture, crop growth climatic information etc, which is useful and necessary for agriculture purposes. For this purpose, microwave remote sensing has evolved as an important tool. Since microwave are able to penetrate more deeply into vegetation and underneath ground surface. It is also preferred to the optical frequency band because microwave can work in all type of weather and have a wide signal dynamic range compared optical wavelengths. However interpretation of microwave scattering from agricultural crops requires an understanding the interaction among microwave, vegetative material and the soil. In order to develop useful forward and inverse models for retrieving the vegetation characteristic, it is necessary to know in detail the dielectric properties and plant structure of the vegetation over the range of expected growing conditions. In this paper, a theoretical model based on microwave interaction with potato crop along with examination of biomass of potato crop with the varying underlying soil moisture is studied. For this purpose, X-band (9.5GHz) scatterometer is used for studying the interaction of microwave with potato crop biomass and underlying soil moisture at various sensor parameters (i.e. angular variation and polarization, HH- and VV-). Although there may be a lot of crop parameters (i.e. crop height, leaf area index, etc) which also gives their effect on microwave. All this parameters are interlinked in the crop

  10. Detection of Decreasing Vegetation Cover Based on Empirical Orthogonal Function and Temporal Unmixing Analysis

    OpenAIRE

    Di Xu; Ruishan Chen; Xiaoshi Xing; Wenpeng Lin

    2017-01-01

    Vegetation plays an important role in the energy exchange of the land surface, biogeochemical cycles, and hydrological cycles. MODIS (MODerate-resolution Imaging Spectroradiometer) EVI (Enhanced Vegetation Index) is considered as a quantitative indicator for examining dynamic vegetation changes. This paper applied a new method of integrated empirical orthogonal function (EOF) and temporal unmixing analysis (TUA) to detect the vegetation decreasing cover in Jiangsu Province of China. The empir...

  11. Relations between morphological settings and vegetation covers in a medium relief landscape of Central Italy

    Directory of Open Access Journals (Sweden)

    S. Pignatti

    2006-06-01

    Full Text Available Mount area, a medium relief structure within the Italian Latium region. The study aims at defining the relationships between vegetation and landform types and highlighting the main morphological characteristics within examined land cover classes. These were the result of the application of a supervised classification method to the first 28 (VISNIR bands of the airborne MIVIS data collected within an extensive survey campaign over Rome Province. The analysis was supported by photo-interpretation of peculiar MIVIS band combinations and by data acquired during field surveys and from a pre-existing vegetation map. The morphometric data were obtained by processing a raster DEM created from topographic maps. These data were processed by means of a new morphometric classification method based on the statistical multivariate investigation of local topographic gradients, calculated along the 8 azimuth directions of each pixel neighbourhood. Such approach quickly estimates the spatial distribution of different types of homogeneous terrain units, emphasizing the impact of erosional and tectonic processes on the overall relief. Mutual relations between morphometric units and vegetation types were assessed by performing a correspondence analysis between the results of the two classifications.

  12. A temporal extension to the parsimonious covering theory.

    Science.gov (United States)

    Wainer, J; Rezende, A de M

    1997-07-01

    In this paper, parsimonious covering theory is extended in such a way that temporal knowledge can be accommodated. In addition to causally associating possible manifestations with disorders, temporal relationships about duration and the time elapsed before a manifestation comes into existence can be represented by a graph. Precise definitions of the solution of a temporal diagnostic problem as well as algorithms to compute the solutions are provided. The medical suitability of the extended parsimonious cover theory is studied in the domain of food-borne disease.

  13. The vegetation cover of New Zealand at the Last Glacial Maximum

    Science.gov (United States)

    Newnham, Rewi; McGlone, Matt; Moar, Neville; Wilmshurst, Janet; Vandergoes, Marcus

    2013-08-01

    A new reconstruction of the vegetation cover for New Zealand at the Last Glacial Maximum (LGM) is presented, based primarily on a database of 66 pollen site records and a more limited range of plant macrofossil and coleopteran records. Extensive forest is evident only from Auckland northwards. Conifer-broadleaf forest similar to that in the region today, but with Agathis australis scarce, persisted in the far north, whilst Nothofagus trees and a range of shrub taxa characterised the more open forests elsewhere in Northland. Survival of Nothofagus-dominated forest in coastal and exposed continental shelf locations to the southwest of Auckland and northwestern South Island is also indicated. Beyond these regions, vegetation cover comprised shrubland- and grassland-dominant communities, with the latter more prominent in eastern areas, to the south and presumably at higher altitudes. Nevertheless the survival of forest trees is indicated unambiguously in most regions apart from the eastern South Island. Thus the concept of 'micro glacial forest refugia' in New Zealand remains supported by this latest glacial vegetation reconstruction and we draw possible parallels with the developing but contentious concept of 'northern cryptic refugia' in Europe. Recent assertions that pollen and beetle reconstructions of the New Zealand LGM vegetation patterns diverge significantly are not supported by this analysis. Rather, the two proxies are readily reconciled if the term 'woody' as indicated by coleoptera is not restricted to tall forest trees but extended to the widespread woody shrub and small tree elements of the New Zealand flora. Regional distinctions in the LGM vegetation reconstruction concur broadly with the contemporary vegetation pattern, suggesting that, along with temperature depression and likely drier growing conditions, a zonal circulation regime with prominent southern westerly winds was important at 21 ka, as it is today. Pollen-climate modelling of the extent of

  14. Fractional Vegetation Cover of East African Wetlands Observed on Ground and from Space

    Science.gov (United States)

    Schmidt, M.; Amler, E.; Guerschmann, J. P.; Scarth, P.; Behn, K.; Thonfeld, F.

    2016-08-01

    Wetlands are important ecosystems providing numerous ecosystem services. They are of particular importance to communities in East Africa where agriculture is the most important economic sector and where food availability to households critical. During an intensive field campaign in the dry season of 2013 were Fractional Vegetation Cover (FVC) measurements, botanical vegetation cover and vegetation structure estimates acquired in three wetland test sites within the East African region. FVC cover data were collated in three strata: ground layer, midstorey and overstorey (woody vegetation greater than 2 m). Fractional cover estimates for the green and no-green vegetative fraction were calculated for Landsat MODIS imagery. These FVC data products were evaluated a) with FVC field data and b) relative to each other for their usability in the East African region. First results show some promise for further studies.

  15. Temporal-spatial characteristics of vegetation cover and desertification of China by using remote sensing data

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on the NOAA advanced very high resolution radiometer (NOAA-AVHRR) remote sensing data of 1982~1999, the normalized difference vegetation index (NDVI) reflecting the surface vegetation cover has been obtained. Using the empirical orthogonal function analysis, the temporal-spatial eigenvectors of NDVI are given, and the characteristics of the spatial distribution of vegetation cover and its temporal variation together with the desertification of China are analyzed. It is found that the surface vegetation cover has seriously deteriorated in most part of China since 1995, along with the intensified desertification. All these are mainly caused by human activities although the climate change is responsible for the damage of surface vegetation cover to some extent.

  16. Examination of the semi-automatic calculation technique of vegetation cover rate by digital camera images.

    Science.gov (United States)

    Takemine, S.; Rikimaru, A.; Takahashi, K.

    The rice is one of the staple foods in the world High quality rice production requires periodically collecting rice growth data to control the growth of rice The height of plant the number of stem the color of leaf is well known parameters to indicate rice growth Rice growth diagnosis method based on these parameters is used operationally in Japan although collecting these parameters by field survey needs a lot of labor and time Recently a laborsaving method for rice growth diagnosis is proposed which is based on vegetation cover rate of rice Vegetation cover rate of rice is calculated based on discriminating rice plant areas in a digital camera image which is photographed in nadir direction Discrimination of rice plant areas in the image was done by the automatic binarization processing However in the case of vegetation cover rate calculation method depending on the automatic binarization process there is a possibility to decrease vegetation cover rate against growth of rice In this paper a calculation method of vegetation cover rate was proposed which based on the automatic binarization process and referred to the growth hysteresis information For several images obtained by field survey during rice growing season vegetation cover rate was calculated by the conventional automatic binarization processing and the proposed method respectively And vegetation cover rate of both methods was compared with reference value obtained by visual interpretation As a result of comparison the accuracy of discriminating rice plant areas was increased by the proposed

  17. Estimation of Fractional Vegetation Cover Based on Digital Camera Survey Data and a Remote Sensing Model

    Institute of Scientific and Technical Information of China (English)

    HU Zhen-qi; HE Fen-qin; YIN Jian-zhong; LU Xia; TANG Shi-lu; WANG Lin-lin; LI Xiao-jing

    2007-01-01

    The objective of this paper is to improve the monitoring speed and precision of fractional vegetation cover (fc). It mainly focuses onfc estimation when fcmax andfcmin are not approximately equal to 100% and 0%, respectively due to using remote sensing image with medium or low spatial resolution. Meanwhile, we present a new method offc estimation based on a random set offc maximum and minimum values from digital camera (DC) survey data and a dimidiate pixel model. The results show that this is a convenient, efficient and accurate method forfc monitoring, with the maximum error -0.172 and correlation coefficient of 0.974 between DC survey data and the estimated value of the remote sensing model. The remaining DC survey data can be used as verification data for the precision of thefc estimation. In general, the estimation offc based on DC survey data and a remote sensing model is a brand-new development trend and deserves further extensive utilization.

  18. Vegetation study in support of the design and optimization of vegetative soil covers, Sandia National Laboratories, Albuquerque, New Mexico.

    Energy Technology Data Exchange (ETDEWEB)

    Peace, Gerald (Jerry) L.; Goering, Timothy James (GRAM inc., Albuquerque, NM); Knight, Paul J. (Marron and Associates, Albuquerque, NM); Ashton, Thomas S. (Marron and Associates, Albuquerque, NM)

    2004-11-01

    A vegetation study was conducted in Technical Area 3 at Sandia National Laboratories, Albuquerque, New Mexico in 2003 to assist in the design and optimization of vegetative soil covers for hazardous, radioactive, and mixed waste landfills at Sandia National Laboratories/New Mexico and Kirtland Air Force Base. The objective of the study was to obtain site-specific, vegetative input parameters for the one-dimensional code UNSAT-H and to identify suitable, diverse native plant species for use on vegetative soil covers that will persist indefinitely as a climax ecological community with little or no maintenance. The identification and selection of appropriate native plant species is critical to the proper design and long-term performance of vegetative soil covers. Major emphasis was placed on the acquisition of representative, site-specific vegetation data. Vegetative input parameters measured in the field during this study include root depth, root length density, and percent bare area. Site-specific leaf area index was not obtained in the area because there was no suitable platform to measure leaf area during the 2003 growing season due to severe drought that has persisted in New Mexico since 1999. Regional LAI data was obtained from two unique desert biomes in New Mexico, Sevilletta Wildlife Refuge and Jornada Research Station.

  19. Relative Spectral Mixture Analysis: a new multitemporal index of total vegetation cover

    Science.gov (United States)

    Okin, G. S.; Liu, C. S.

    2005-12-01

    High temporal resolution remote sensing provides an opportunity to monitor phenological variability and interannual changes in vegetation cover across diverse. A principal tool in multitemporal vegetation monitoring has been the Normalized Difference Vegetation Index. NDVI provides an index of the depth of the red edge and is usually interpreted as a measure of vegetation greenness and/or green vegetation cover. NDVI as a measure of phenology has several failings, particularly when applied over large areas: 1) NDVI is sensitive to the spectra of the soil background, particularly in partially or seasonally vegetated areas, 2) NDVI does not provide information about the non-photosynthetic portion of standing biomass, and 3) NDVI is very sensitive to the presence of small amounts of snow in a pixel. A new method for measuring vegetation phenology has been developed called Relative Spectral Mixture Analysis. RSMA uses a linear spectral mixture analysis to provide an index of the relative cover of four landscape components: green vegetation (GV), nonphotosynthetic vegetation (NPV), soil, and snow. RSMA uses generalized spectral for GV, NPV and snow, but does not require knowledge of the background soil spectra. This allows RSMA to be applied over very large areas (continental-scale) in which the soil background is highly diverse. RSMA has been implemented in the IDL language and used to analyze MODIS nadir-adjusted reflectance products from 2000 to the present. Our results show that RSMA GV index values are highly correlated with NDVI, except in regions with snow where RSMA outperforms NDVI. As a result RSMA GV indices and total vegetation indices (GV+NPV) can be used to extract information from spectral timeseries such as the onset of greenness, the termination of greenness, maximum vegetation cover, integrated vegetation cover (an index of NPP), length of the growing season, and duration of fodder availability. RSMA snow indices correlate well with other satellite

  20. Cryptogamic covers control spectral vegetation indices and their seasonal variation in dryland systems

    Science.gov (United States)

    Rodriguez-Caballero, Emilio; Knerr, Tanja; Büdel, Burkhard; Hill, Joachim; Weber, Bettina

    2016-04-01

    Remote sensing data provide spatially continuous information on vegetation dynamics by means of long-term series of vegetation indices (VI). However, most of these indices show problematic results in drylands, as a consequence of the scarce vegetation cover and the strong effect of the open space between plants. Open soil between plants as well as rock surfaces in dryland ecosystems are often covered by complex communities of cyanobacteria, algae, lichens and mosses. These cryptogamic covers show a faster phenological response to water pulses than vascular vegetation, turning green almost immediately after the first rain following a dry period and modifying their spectral response. However, only few studies quantified the effects of cryptogamic covers on VI, and none of them considered them in the analysis of temporal series of satellite images, where differences in physiology and reflectance between cryptogamic covers and vascular vegetation interact. For this reason, we quantified how cryptogamic covers modify the Normalized Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI), based on field and lab spectral measurements. For two different biocrust-dominated ecosystems within the South African Karoo, we analyzed the effect of biocrusts on spectrally analyzed vegetation dynamics using multi-temporal series of VI obtained from LANDSAT and MODIS images . Cryptogamic covers exerted a considerable effect on both NDVI and EVI calculated from field and lab spectra. As previously described for vegetation, also increasing cryptogam cover caused an increase of both VI values, and this effect also became apparent at LANDSAT image scale. However, the response of VI extracted from LANDSAT images upon environmental factors differed between pixels dominated by cryptogams and vascular vegetation. Whereas vegetation showed the highest changes in VI values in response to water availability and temperature, cryptogamic covers, which are the main surface

  1. Cover crop frequency and compost effects on a legume-rye cover crop during 8 years of organic vegetables

    Science.gov (United States)

    Organic matter inputs from compost or cover crops (CC) are important to maintain or improve soil quality, but their impact in high-value vegetable production systems are not well understood. Therefore, we evaluated the effects of CC frequency (every winter versus every 4th winter) and yard-waste co...

  2. Estimating Achievable Accuracy for Global Imaging Spectroscopy Measurement of Non-Photosynthetic Vegetation Cover

    Science.gov (United States)

    Dennison, P. E.; Kokaly, R. F.; Daughtry, C. S. T.; Roberts, D. A.; Thompson, D. R.; Chambers, J. Q.; Nagler, P. L.; Okin, G. S.; Scarth, P.

    2016-12-01

    Terrestrial vegetation is dynamic, expressing seasonal, annual, and long-term changes in response to climate and disturbance. Phenology and disturbance (e.g. drought, insect attack, and wildfire) can result in a transition from photosynthesizing "green" vegetation to non-photosynthetic vegetation (NPV). NPV cover can include dead and senescent vegetation, plant litter, agricultural residues, and non-photosynthesizing stem tissue. NPV cover is poorly captured by conventional remote sensing vegetation indices, but it is readily separable from substrate cover based on spectral absorption features in the shortwave infrared. We will present past research motivating the need for global NPV measurements, establishing that mapping seasonal NPV cover is critical for improving our understanding of ecosystem function and carbon dynamics. We will also present new research that helps determine a best achievable accuracy for NPV cover estimation. To test the sensitivity of different NPV cover estimation methods, we simulated satellite imaging spectrometer data using field spectra collected over mixtures of NPV, green vegetation, and soil substrate. We incorporated atmospheric transmittance and modeled sensor noise to create simulated spectra with spectral resolutions ranging from 10 to 30 nm. We applied multiple methods of NPV estimation to the simulated spectra, including spectral indices, spectral feature analysis, multiple endmember spectral mixture analysis, and partial least squares regression, and compared the accuracy and bias of each method. These results prescribe sensor characteristics for an imaging spectrometer mission with NPV measurement capabilities, as well as a "Quantified Earth Science Objective" for global measurement of NPV cover. Copyright 2016, all rights reserved.

  3. Remote Sensing of Fractional Green Vegetation Cover Using Spatially-Interpolated Endmembers

    OpenAIRE

    Ryutaro Tateishi; Brian Johnson; Toshiyuki Kobayashi

    2012-01-01

    Fractional green vegetation cover (FVC) is a useful parameter for many environmental and climate-related applications. A common approach for estimating FVC involves the linear unmixing of two spectral endmembers in a remote sensing image; bare soil and green vegetation. The spectral properties of these two endmembers are typically determined based on field measurements, estimated using additional data sources (e.g., soil databases or land cover maps), or extracted directly from the imagery. M...

  4. Vegetation Cover based on Eagleson's Ecohydrological Optimality in Northeast China Transect (NECT)

    Science.gov (United States)

    Cong, Z.; Mo, K.; Qinshu, L.; Zhang, L.

    2016-12-01

    Vegetation is considered as the indicator of climate, thus the study of vegetation growth and distribution is of great importance to cognize the ecosystem construction and functions. Vegetation cover is used as an important index to describe vegetation conditions. In Eagleson's ecohydrological optimality, the theoretical optimal vegetation cover M* can be estimated by solving water balance equations. In this study, the theory is applied in the Northeast China Transect (NECT), one of International Geosphere-Biosphere Programs (IGBP) terrestrial transects. The spatial distribution of actual vegetation cover M, which is derived from Normalized Vegetation Index (NDVI) from Moderate-resolution Imaging Spectroradiometer (MODIS), shows that there is a significant gradient ranging from 1 in the east forests to 0 in the west desert. The result indicates that the theoretical M* fits the actual M well (for forest, M* = 0.822 while M = 0.826; for grassland, M* = 0.353 while M = 0.352; the correlation coefficient between M and M* is 0.81). The reasonable calculated proportion of water balance components further demonstrates the applicability of the ecohydrological optimality theory. M* increases with the increase of LAI, leaf angle, stem fraction and temperature, and decreases with the increase of precipitation amount. This method offers the possibility to analyze the impacts of climate change to vegetation cover quantitatively, thus providing advices for eco-restoration projects.

  5. Impact of Vegetative Cover on Runoff and Soil Erosion at Hillslope Scale in Lanjaron, Spain

    NARCIS (Netherlands)

    Duran Zuazo, V.H.; Francia-Martinez, J.R.; Martinez-Raya, A.

    2004-01-01

    Soil loss and surface runoff patterns over a four-year period (1997¿2000) were studied in erosion plots from three hillslopes under different vegetative covers (Rosmarinus officinalis, Triticum aestivum and natural-spontaneous vegetation) in Lanjaron (Alpujarras) on the south flank of the Sierra Nev

  6. 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

  7. 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

  8. Mutual influence between climate and vegetation cover through satellite data in Egypt

    Science.gov (United States)

    El-Shirbeny, Mohammed A.; Aboelghar, Mohamed A.; Arafat, Sayed M.; El-Gindy, Abdel-Ghany M.

    2011-11-01

    The effect of vegetation cover on climatic change has not yet observed in Egypt. In the current study, Ismailia Governorate was selected as a case study to assess the impact of the vegetation cover expansion on both land surface and air temperature during twenty-eight years from 1983 to 2010. This observation site was carefully selected as a clear example for the highly rate of reclamation and vegetation expansion process in Egypt. Land Surface Temperature (LST) that were extracted from NOAA/AVHRR satellite data and air temperature (Tair) data that were collected from ground stations, were correlated with the expansion of vegetation cover that was delineated using Landsat TM and Landsat ETM+ data. The result showed that (LST) decreased by about 2.3°C while (Tair) decreased by about 1.6°C with the expansion of the cultivated land during twenty-eight years.

  9. [Advance in researches on vegetation cover and management factor in the soil erosion prediction model].

    Science.gov (United States)

    Zhang, Yan; Yuan, Jianping; Liu, Baoyuan

    2002-08-01

    Vegetation cover and land management are the main limiting factors of soil erosion, and quantitative evaluation on the effect of different vegetation on soil erosion is essential to land use and soil conservation planning. The vegetation cover and management factor (C) in the universal soil loss equation (USLE) is an index to evaluate this effect, which has been studied deeply and used widely. However, the C factor study is insufficient in China. In order to strengthen the research of C factor, this paper reviewed the developing progress of C factor, and compared the methods of estimating C value in different USLE versions. The relative studies in China were also summarized from the aspects of vegetation canopy coverage, soil surface cover, and root density. Three problems in C factor study were pointed out. The authors suggested that cropland C factor research should be furthered, and its methodology should be unified in China to represent reliable C values for soil loss prediction and conservation planning.

  10. Impacts of Snow Cover on Vegetation Phenology in the Arctic from Satellite Data

    Institute of Scientific and Technical Information of China (English)

    ZENG Heqing; JIA Gensuo

    2013-01-01

    The dynamics of snow cover is considered an essential factor in phenological changes in Arctic tundra and other northern biomes.The Moderate Resolution Imaging Spectroradiometer (MODIS)/Terra satellite data were selected to monitor the spatial and temporal heterogeneity of vegetation phenology and the timing of snow cover in western Arctic Russia (the Yamal Peninsula) during the period 2000-10.The magnitude of changes in vegetation phenology and the timing of snow cover were highly heterogeneous across latitudinal gradients and vegetation types in western Arctic Russia.There were identical latitudinal gradients for "start of season" (SOS) (r2 =0.982,p<0.0001),"end of season" (EOS) (r2 =0.938,p<0.0001),and "last day of snow cover" (LSC) (r2 =0.984,p<0.0001),while slightly weaker relationships between latitudinal gradients and "first day of snow cover" (FSC) were observed (r2 =0.48,p<0.0042).Delayed SOS and FSC,and advanced EOS and LSC were found in the south of the region,while there were completely different shifts in the north.SOS for the various land cover features responded to snow cover differently,while EOS among different vegetation types responded to snowfall almost the same.The timing of snow cover is likely a key driving factor behind the dynamics of vegetation phenology over the Arctic tundra.The present study suggests that snow cover urgently needs more attention to advance understanding of vegetation phenology in the future.

  11. Landsat-Based Woody Vegetation Cover Monitoring in Southern African Savannahs

    Science.gov (United States)

    Symeonakis, E.; Petroulaki, K.; Higginbottom, T.

    2016-06-01

    Mapping woody cover over large areas can only be effectively achieved using remote sensing data and techniques. The longest continuously operating Earth-observation program, the Landsat series, is now freely-available as an atmospherically corrected, cloud masked surface reflectance product. The availability and length of the Landsat archive is thus an unparalleled Earth-observation resource, particularly for long-term change detection and monitoring. Here, we map and monitor woody vegetation cover in the Northwest Province of South Africa, an area of more than 100,000 km2 covered by 11 Landsat scenes. We employ a multi-temporal approach with dry-season data from 7 epochs between 1990 to 2015. We use 0.5 m-pixel colour aerial photography to collect > 15,000 point samples for training and validating Random Forest classifications of (i) woody vegetation cover, (ii) other vegetation types (including grasses and agricultural land), and (iii) non-vegetated areas (i.e. urban areas and bare land). Overall accuracies for all years are around 80 % and overall kappa between 0.45 and 0.66. Woody vegetation covers a quarter of the Province and is the most accurately mapped class (balanced accuracies between 0.74-0.84 for the 7 epochs). There is a steady increase in woody vegetation cover over the 25-year-long period of study in the expense of the other vegetation types. We identify potential woody vegetation encroachment 'hot-spots' where mitigation measures might be required and thus provide a management tool for the prioritisation of such measures in degraded and food-insecure areas.

  12. LANDSAT-BASED WOODY VEGETATION COVER MONITORING IN SOUTHERN AFRICAN SAVANNAHS

    Directory of Open Access Journals (Sweden)

    E. Symeonakis

    2016-06-01

    Full Text Available Mapping woody cover over large areas can only be effectively achieved using remote sensing data and techniques. The longest continuously operating Earth-observation program, the Landsat series, is now freely-available as an atmospherically corrected, cloud masked surface reflectance product. The availability and length of the Landsat archive is thus an unparalleled Earth-observation resource, particularly for long-term change detection and monitoring. Here, we map and monitor woody vegetation cover in the Northwest Province of South Africa, an area of more than 100,000 km2 covered by 11 Landsat scenes. We employ a multi-temporal approach with dry-season data from 7 epochs between 1990 to 2015. We use 0.5 m-pixel colour aerial photography to collect > 15,000 point samples for training and validating Random Forest classifications of (i woody vegetation cover, (ii other vegetation types (including grasses and agricultural land, and (iii non-vegetated areas (i.e. urban areas and bare land. Overall accuracies for all years are around 80 % and overall kappa between 0.45 and 0.66. Woody vegetation covers a quarter of the Province and is the most accurately mapped class (balanced accuracies between 0.74-0.84 for the 7 epochs. There is a steady increase in woody vegetation cover over the 25-year-long period of study in the expense of the other vegetation types. We identify potential woody vegetation encroachment 'hot-spots' where mitigation measures might be required and thus provide a management tool for the prioritisation of such measures in degraded and food-insecure areas.

  13. Performance of quantitative vegetation sampling methods across gradients of cover in Great Basin plant communities

    Science.gov (United States)

    Pilliod, David S.; Arkle, Robert S.

    2013-01-01

    Resource managers and scientists need efficient, reliable methods for quantifying vegetation to conduct basic research, evaluate land management actions, and monitor trends in habitat conditions. We examined three methods for quantifying vegetation in 1-ha plots among different plant communities in the northern Great Basin: photography-based grid-point intercept (GPI), line-point intercept (LPI), and point-quarter (PQ). We also evaluated each method for within-plot subsampling adequacy and effort requirements relative to information gain. We found that, for most functional groups, percent cover measurements collected with the use of LPI, GPI, and PQ methods were strongly correlated. These correlations were even stronger when we used data from the upper canopy only (i.e., top “hit” of pin flags) in LPI to estimate cover. PQ was best at quantifying cover of sparse plants such as shrubs in early successional habitats. As cover of a given functional group decreased within plots, the variance of the cover estimate increased substantially, which required more subsamples per plot (i.e., transect lines, quadrats) to achieve reliable precision. For GPI, we found that that six–nine quadrats per hectare were sufficient to characterize the vegetation in most of the plant communities sampled. All three methods reasonably characterized the vegetation in our plots, and each has advantages depending on characteristics of the vegetation, such as cover or heterogeneity, study goals, precision of measurements required, and efficiency needed.

  14. Detection of Decreasing Vegetation Cover Based on Empirical Orthogonal Function and Temporal Unmixing Analysis

    Directory of Open Access Journals (Sweden)

    Di Xu

    2017-01-01

    Full Text Available Vegetation plays an important role in the energy exchange of the land surface, biogeochemical cycles, and hydrological cycles. MODIS (MODerate-resolution Imaging Spectroradiometer EVI (Enhanced Vegetation Index is considered as a quantitative indicator for examining dynamic vegetation changes. This paper applied a new method of integrated empirical orthogonal function (EOF and temporal unmixing analysis (TUA to detect the vegetation decreasing cover in Jiangsu Province of China. The empirical orthogonal function (EOF statistical results provide vegetation decreasing/increasing trend as prior information for temporal unmixing analysis. Temporal unmixing analysis (TUA results could reveal the dominant spatial distribution of decreasing vegetation. The results showed that decreasing vegetation areas in Jiangsu are distributed in the suburbs and newly constructed areas. For validation, the vegetation’s decreasing cover is revealed by linear spectral mixture from Landsat data in three selected cities. Vegetation decreasing areas pixels are also calculated from land use maps in 2000 and 2010. The accuracy of integrated empirical orthogonal function and temporal unmixing analysis method is about 83.14%. This method can be applied to detect vegetation change in large rapidly urbanizing areas.

  15. Deforestation and benthic indicators: how much vegetation cover is needed to sustain healthy Andean streams?

    Directory of Open Access Journals (Sweden)

    Carlos Iñiguez-Armijos

    Full Text Available Deforestation in the tropical Andes is affecting ecological conditions of streams, and determination of how much forest should be retained is a pressing task for conservation, restoration and management strategies. We calculated and analyzed eight benthic metrics (structural, compositional and water quality indices and a physical-chemical composite index with gradients of vegetation cover to assess the effects of deforestation on macroinvertebrate communities and water quality of 23 streams in southern Ecuadorian Andes. Using a geographical information system (GIS, we quantified vegetation cover at three spatial scales: the entire catchment, the riparian buffer of 30 m width extending the entire stream length, and the local scale defined for a stream reach of 100 m in length and similar buffer width. Macroinvertebrate and water quality metrics had the strongest relationships with vegetation cover at catchment and riparian scales, while vegetation cover did not show any association with the macroinvertebrate metrics at local scale. At catchment scale, the water quality metrics indicate that ecological condition of Andean streams is good when vegetation cover is over 70%. Further, macroinvertebrate community assemblages were more diverse and related in catchments largely covered by native vegetation (>70%. Our results suggest that retaining an important quantity of native vegetation cover within the catchments and a linkage between headwater and riparian forests help to maintain and improve stream biodiversity and water quality in Andean streams affected by deforestation. This research proposes that a strong regulation focused to the management of riparian buffers can be successful when decision making is addressed to conservation/restoration of Andean catchments.

  16. Deforestation and benthic indicators: how much vegetation cover is needed to sustain healthy Andean streams?

    Science.gov (United States)

    Iñiguez-Armijos, Carlos; Leiva, Adrián; Frede, Hans-Georg; Hampel, Henrietta; Breuer, Lutz

    2014-01-01

    Deforestation in the tropical Andes is affecting ecological conditions of streams, and determination of how much forest should be retained is a pressing task for conservation, restoration and management strategies. We calculated and analyzed eight benthic metrics (structural, compositional and water quality indices) and a physical-chemical composite index with gradients of vegetation cover to assess the effects of deforestation on macroinvertebrate communities and water quality of 23 streams in southern Ecuadorian Andes. Using a geographical information system (GIS), we quantified vegetation cover at three spatial scales: the entire catchment, the riparian buffer of 30 m width extending the entire stream length, and the local scale defined for a stream reach of 100 m in length and similar buffer width. Macroinvertebrate and water quality metrics had the strongest relationships with vegetation cover at catchment and riparian scales, while vegetation cover did not show any association with the macroinvertebrate metrics at local scale. At catchment scale, the water quality metrics indicate that ecological condition of Andean streams is good when vegetation cover is over 70%. Further, macroinvertebrate community assemblages were more diverse and related in catchments largely covered by native vegetation (>70%). Our results suggest that retaining an important quantity of native vegetation cover within the catchments and a linkage between headwater and riparian forests help to maintain and improve stream biodiversity and water quality in Andean streams affected by deforestation. This research proposes that a strong regulation focused to the management of riparian buffers can be successful when decision making is addressed to conservation/restoration of Andean catchments.

  17. Vegetation cover change detection in Chamela-Cuixamala, Mexico

    Science.gov (United States)

    De la Barreda Bautista, Betsabé; López-Caloca, Alejandra A.

    2009-09-01

    In Mexico, and everywhere else, the ecosystems are constantly changing either by natural factors or anthropogenic activity. Remote sensing has been a key tool to monitoring these changes throughout history and also to understanding the ecological dynamics. Hence, sustainable development plans have been created in order to improve the decisionmaking process; thus, this paper analyses deforestation impact in a very important natural resourcing area in Mexico, considering land cover changes. The study area is located in the coast of Jalisco, Mexico, where deforestation and fragmentation as well as high speed touristic development have been the causes of enormous biodiversity losses; the Chamela-Cuixamala Biosphere Reserve is located within this area. It has great species richness and vast endemism. The exploitation of this biome is widespread all over the country and it has already had an impact in the reserve. The change detection multi-temporal study uses Landsat satellite imagery during the 1970-2003 time period. Thus, the objective of change detection analysis is to detect and localize environmental changes through time. The change detection method consists in producing an image of change likelihood (by post-classification, multivariate alteration detection) and thresholding it in order to produce the change map. Experimental results confirmed that the patterns of land use and land cover changes have increased significantly over the last decade. This study also analyzes the deforestation impact on biodiversity. The analysis validation was carried out using field and statistic data. Spatial-temporal changing range enables the analysis of the structural and dynamic effects on the ecosystem and it enhances better decision-making and public environmental policies to decrease or eliminate deforestation, the creation of natural protected areas as a biodiversity conservation method, and counteracting the global warming phenomena.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-01-17

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

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

    Directory of Open Access Journals (Sweden)

    Mike Serrato

    2012-01-01

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

  20. Nonlinear vegetation cover changes in the North Ethiopian Highlands: Evidence from the Lake Ashenge closed basin

    Energy Technology Data Exchange (ETDEWEB)

    Lanckriet, Sil, E-mail: sil.lanckriet@ugent.be [Department of Geography, Ghent University, Krijgslaan 281 (S8), B-9000 Ghent (Belgium); Rucina, Stephen [National Museum of Kenya, Earth Science Department, Palynology Section, P.O. Box 40658 00100, Nairobi (Kenya); Frankl, Amaury [Department of Geography, Ghent University, Krijgslaan 281 (S8), B-9000 Ghent (Belgium); Ritler, Alfons [Centre for Development and Environment, University of Bern, Hallerstrasse 10, CH-3012 Bern (Switzerland); Gelorini, Vanessa [Department of Geology and Soil Science, Ghent University, Krijgslaan 281 (S8), B-9000 Ghent (Belgium); Nyssen, Jan [Department of Geography, Ghent University, Krijgslaan 281 (S8), B-9000 Ghent (Belgium)

    2015-12-01

    Vegetation cover changes in African drylands are often thought to result from population growth, social factors and aridification. Here we show that long-term vegetation proxy records can help disentangling these main driving factors. Taking the case of North Ethiopia, we performed an integrated investigation of land cover changes over the last four centuries around the endorheic Lake Ashenge, as derived from pollen analysis and repeat photography complemented with information from historical sources. Pollen and sediment analysis of radiocarbon-dated lake deposits shows a phase of environmental destabilization during the 18th century, after a more stable previous period. This is evidenced by decreases of tree pollen (Juniperus, Olea, Celtis, Podocarpus < 5%), increases in Poaceae (> 40%) and deposition of coarser silt lake sediments (> 70%). Quantitative analysis of 30 repeated landscape photographs around the lake indicates a gradual decline of the vegetation cover since a relative maximum during the mid-19th Century. Vegetation cover declined sharply between the 1950s and the 1980s, but has since begun to recover. Overall, the data from around Lake Ashenge reveal a nonlinear pattern of deforestation and forest regrowth with several periods of vegetation cover change over the past four centuries. While there is forcing of regional drought and the regional land tenure system, the cyclic changes do not support a simplified focus on aridification or population growth. - Highlights: • Vegetation cover changes are often related with population growth or climate • We investigated land cover changes over the last four centuries near Lake Ashenge • Overall, the data reveal a nonlinear pattern of deforestation and forest regrowth.

  1. Modeling debris-covered glaciers: extension due to steady debris input

    Directory of Open Access Journals (Sweden)

    L. S. Anderson

    2015-11-01

    Debris-forced glacier extension decreases the ratio of accumulation zone to total glacier area (AAR. The model reproduces first-order relationships between debris cover, AARs, and glacier surface velocities from glaciers in High Asia. We provide a quantitative, theoretical foundation to interpret the effect of debris cover on the moraine record, and to assess the effects of climate change on debris-covered glaciers.

  2. Separation and extension of cover inequalities for second-order conic knapsack constraints with GUBs

    DEFF Research Database (Denmark)

    Atamtürk, Alper; Muller, Laurent Flindt; Pisinger, David

    We consider the second-order conic equivalent of the classic knapsack polytope where the variables are subject to generalized upper bound constraints. We describe and compare a number of separation and extension algorithms which make use of the extra structure implied by the generalized upper bound...... constraints in order to strengthen the second-order conic equivalent of the classic cover cuts. We show that determining whether a cover can be extended with a variable is NP-hard. Computational experiments are performed comparing the proposed separation and extension algorithms. These experiments show...... that applying these extended cover cuts can greatly improve solution time of second-order cone programs....

  3. Fractional vegetation cover estimation based on an improved selective endmember spectral mixture model.

    Directory of Open Access Journals (Sweden)

    Ying Li

    Full Text Available Vegetation is an important part of ecosystem and estimation of fractional vegetation cover is of significant meaning to monitoring of vegetation growth in a certain region. With Landsat TM images and HJ-1B images as data source, an improved selective endmember linear spectral mixture model (SELSMM was put forward in this research to estimate the fractional vegetation cover in Huangfuchuan watershed in China. We compared the result with the vegetation coverage estimated with linear spectral mixture model (LSMM and conducted accuracy test on the two results with field survey data to study the effectiveness of different models in estimation of vegetation coverage. Results indicated that: (1 the RMSE of the estimation result of SELSMM based on TM images is the lowest, which is 0.044. The RMSEs of the estimation results of LSMM based on TM images, SELSMM based on HJ-1B images and LSMM based on HJ-1B images are respectively 0.052, 0.077 and 0.082, which are all higher than that of SELSMM based on TM images; (2 the R2 of SELSMM based on TM images, LSMM based on TM images, SELSMM based on HJ-1B images and LSMM based on HJ-1B images are respectively 0.668, 0.531, 0.342 and 0.336. Among these models, SELSMM based on TM images has the highest estimation accuracy and also the highest correlation with measured vegetation coverage. Of the two methods tested, SELSMM is superior to LSMM in estimation of vegetation coverage and it is also better at unmixing mixed pixels of TM images than pixels of HJ-1B images. So, the SELSMM based on TM images is comparatively accurate and reliable in the research of regional fractional vegetation cover estimation.

  4. Fractional vegetation cover estimation based on an improved selective endmember spectral mixture model.

    Science.gov (United States)

    Li, Ying; Wang, Hong; Li, Xiao Bing

    2015-01-01

    Vegetation is an important part of ecosystem and estimation of fractional vegetation cover is of significant meaning to monitoring of vegetation growth in a certain region. With Landsat TM images and HJ-1B images as data source, an improved selective endmember linear spectral mixture model (SELSMM) was put forward in this research to estimate the fractional vegetation cover in Huangfuchuan watershed in China. We compared the result with the vegetation coverage estimated with linear spectral mixture model (LSMM) and conducted accuracy test on the two results with field survey data to study the effectiveness of different models in estimation of vegetation coverage. Results indicated that: (1) the RMSE of the estimation result of SELSMM based on TM images is the lowest, which is 0.044. The RMSEs of the estimation results of LSMM based on TM images, SELSMM based on HJ-1B images and LSMM based on HJ-1B images are respectively 0.052, 0.077 and 0.082, which are all higher than that of SELSMM based on TM images; (2) the R2 of SELSMM based on TM images, LSMM based on TM images, SELSMM based on HJ-1B images and LSMM based on HJ-1B images are respectively 0.668, 0.531, 0.342 and 0.336. Among these models, SELSMM based on TM images has the highest estimation accuracy and also the highest correlation with measured vegetation coverage. Of the two methods tested, SELSMM is superior to LSMM in estimation of vegetation coverage and it is also better at unmixing mixed pixels of TM images than pixels of HJ-1B images. So, the SELSMM based on TM images is comparatively accurate and reliable in the research of regional fractional vegetation cover estimation.

  5. Land cover change during a period of extensive landscape restoration in Ningxia Hui Autonomous Region, China.

    Science.gov (United States)

    Cadavid Restrepo, Angela M; Yang, Yu Rong; Hamm, Nicholas A S; Gray, Darren J; Barnes, Tamsin S; Williams, Gail M; Soares Magalhães, Ricardo J; McManus, Donald P; Guo, Danhuai; Clements, Archie C A

    2017-11-15

    Environmental change has been a topic of great interest over the last century due to its potential impact on ecosystem services that are fundamental for sustainable development and human well-being. Here, we assess and quantify the spatial and temporal variation in land cover in Ningxia Hui Autonomous Region (NHAR), China. With high-resolution (30m) imagery from Landsat 4/5-TM and 8-OLI for the entire region, land cover maps of the region were created to explore local land cover changes in a spatially explicit way. The results suggest that land cover changes observed in NHAR from 1991 to 2015 reflect the main goals of a national policy implemented there to recover degraded landscapes. Forest, herbaceous vegetation and cultivated land increased by approximately 410,200ha, 708,600ha and 164,300ha, respectively. The largest relative land cover change over the entire study period was the increase in forestland. Forest growth resulted mainly from the conversion of herbaceous vegetation (53.8%) and cultivated land (30.8%). Accurate information on the local patterns of land cover in NHAR may contribute to the future establishment of better landscape policies for ecosystem management and protection. Spatially explicit information on land cover change may also help decision makers to understand and respond appropriately to emerging environmental risks for the local population. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. [Change trend of vegetation cover in Beijing metropolitan region before and after the 2008 Olympics].

    Science.gov (United States)

    Sun, Xiao-Peng; Wang, Tian-Ming; Wu, Jian-Guo; Ge, Jian-Ping

    2012-11-01

    The MODIS-NDVI data from 2000 to 2009 were used to analyze the temporal dynamics and spatial distribution of the vegetation cover in the Beijing metropolitan region before and after the 2008 Olympics. During the study period, the proportion of the significantly increased pixels of NDVI occupied 20.7% while that of the significantly decreased pixels only occupied 4.1% of the total, and the decreasing rate of the NDVI was slightly faster than the increasing rate. The significant changes of the NDVI were mainly concentrated in the low altitude and small slope areas with intensive human activities, and two bands were formed in the plain area, i. e., the vegetation increasing band within the 5th Ring Road and the vegetation decreasing band from the 5th Ring Road to the outside areas of the 6th Ring Road. In the areas with significant vegetation change, there was an obvious transition between the high and low NDVI sections but less change in the medium NDVI section, mainly due to the conversion of land cover type. In the Capital function core area and ecological conservation zones, vegetation change represented a positive trend; while in the urban function expansion area and urban development area, vegetation change had the dual characteristics of both positive and negative trends. A series of ecological engineering projects during the preparatory period of the 2008 Olympics was the main cause of the vegetation increase in the study area.

  7. Using Unmanned Aerial Vehicles to Assess Vegetative Cover in Sagebrush Steppe Ecosytstems

    Energy Technology Data Exchange (ETDEWEB)

    Robert P. Breckenridge

    2005-09-01

    The Idaho National Laboratory (INL), in conjunction with the University of Idaho, is evaluating novel approaches for using unmanned aerial vehicles (UAVs) as a quicker and safer method for monitoring biotic resources. Evaluating vegetative cover is an important factor in understanding the sustainability of many ecosystems. In assessing vegetative cover, methods that improve accuracy and cost efficiency could revolutionize how biotic resources are monitored on western federal lands. Sagebrush steppe ecosystems provide important habitat for a variety of species, some of which are important indicator species (e.g., sage grouse). Improved methods are needed to support monitoring these habitats because there are not enough resource specialists or funds available for comprehensive ground evaluation of these ecosystems. In this project, two types of UAV platforms (fixed wing and helicopter) were used to collect still-frame imagery to assess cover in sagebrush steppe ecosystems. This paper discusses the process for collecting and analyzing imagery from the UAVs to (1) estimate total percent cover, (2) estimate percent cover for six different types of vegetation, and (3) locate sage grouse based on representative decoys. The field plots were located on the INL site west of Idaho Falls, Idaho, in areas with varying amounts and types of vegetative cover. A software program called SamplePoint developed by the U.S. Department of Agriculture, Agricultural Research Service (USDA-ARS) was used to evaluate the imagery for percent cover for the six vegetation types (bare ground, litter, shrubs, dead shrubs, grasses, and forbs). Results were compared against standard field measurements to assess accuracy.

  8. The contribution of vegetation cover and bare soil to pixel reflectance in an arid ecosystem

    Science.gov (United States)

    Steele, C. M.; Smith, A.; Campanella, A.; Rango, A.

    2008-12-01

    The heterogeneity of vegetation and soils in arid and semi-arid environments complicates the analysis of medium spatial resolution remotely sensed imagery. A single pixel may contain several different types of vegetation, as well as a sizeable proportion of bare soil. We have used linear mixture modeling to explore the contribution of vegetation cover and bare soil to pixel reflectance. In October, 2006, aerial imagery (0.25 m spatial resolution) was acquired for our study sites in the Jornada Experimental Range, southern New Mexico. Imagery was also acquired from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) for June and November, 2006. These data corresponded with pre- and post monsoon conditions. Object-based feature extraction was used to classify the aerial imagery to shrub, grass and bare ground cover classes. Percent cover was then calculated for each cover class. Visible-near-infrared and shortwave infrared ASTER reflectance data from both dates were combined into a single 18-band dataset (30 m spatial resolution). A vector overlay from the classification results of the aerial imagery was used to define pure endmember pixels in the ASTER imagery. Estimates of the proportions of shrub, grass and bare ground cover from the linear mixture modeling approach were compared with cover calculated using feature extraction from the aerial imagery. The results indicate that reflectance in ASTER pixels is likely to be a linear combination of the cover proportions of the three main cover types (shrubs, grass, bare ground). However, noticeable outliers in the relationship between cover calculated from each method, indicate there may be other variables that affect the accuracy with which we can estimate cover using linear mixture modeling.

  9. Long-term monitoring of stream bank stability under different vegetation cover

    Science.gov (United States)

    Krzeminska, Dominika; Skaalsveen, Kamilla; Kerkhof, Tjibbe

    2017-04-01

    Vegetated buffer zones are common environmental measures in many countries, including Norway. The presence of riparian vegetation on stream banks not only provides ecological benefits but also influence bank slope stability, through several complex interactions between riparian vegetation and hydro - mechanical processes. The hydrological processes associated with slope stability are complex and yet difficult to quantify, especially because their transient effects (e.g. changes throughout the vegetation life cycle). Additionally, there is very limited amount of field scale research focusing on investigation of coupled hydrological and mechanical influence of vegetation on stream bank behavior, accounting for both seasonal time scale and different vegetation type, and none dedicated to marine clay soils (typically soil for Norway). In order to fill this gap we established continues, long term hydrogeological monitoring o selected cross - section within stream bank, covered with different types of vegetation, typical for Norwegian agriculture areas (grass, shrubs, and trees). The monitoring involves methods such as spatial and temporal monitoring of soil moisture conditions, ground water level and fluctuation of water level in the stream. Herein we will present first 10 months of monitoring data: observed hydrological trends and differences between three cross - sections. Moreover, we will present first modelling exercises that aims to estimate stream banks stability with accounting on presence of different vegetation types using BSTEM and HYDRUS models. With this presentation, we would like to stimulate the discussion and get feedback that could help us to improve both, our experimental set up and analysis approach.

  10. Soil phosphorus forms as quality indicators of soils under different vegetation covers.

    Science.gov (United States)

    Turrión, María-Belén; López, Olga; Lafuente, Francisco; Mulas, Rafael; Ruipérez, César; Puyo, Alberto

    2007-05-25

    The type of vegetation cover determines the physicochemical and biological properties of the soil over which they are developing. The objective of this study was to determine the effect of different vegetation covers on the forms of soil phosphorus, in order to know which of these forms can be used as a soil quality indicator. The experimental area was located on the acidic plateau at the North of Palencia (North Spain), where an area was selected vegetation covers very close to each other: pine (Pinus sylvestris), oak (Quercus pyrenaica), and three different shrub species (Arctostaphylos uva-ursi, Erica australis and Halimium alyssoides). The Ah horizon was sampled and pH, total organic C (C(org)), total N (N), cationic exchange capacity (CEC), sum of bases (S) and P forms by a sequential fractionation were analysed. Results showed that oak and A. uva-ursi improve the considered soil parameters (pH, C(org)/N ratio, CEC, and S) and provide soils of better quality. Inorganic soil P forms were influenced in greater extent by the vegetation cover than were P organic forms. Labile inorganic P forms could be used as indicators of soil quality. The organic P forms were less sensitive than inorganic ones to the indicated improvements.

  11. Woody vegetation and land cover changes in the Sahel of Mali (1967–2011)

    DEFF Research Database (Denmark)

    Spiekermann, Raphael; Brandt, Martin; Samimi, Cyrus

    2014-01-01

    In the past 50 years, the Sahel has experienced significant tree- and land cover changes accelerated by human expansion and prolonged droughts during the 1970s and 1980s. This study uses remote sensing techniques, supplemented by ground-truth data to compare pre-drought woody vegetation and land...

  12. Using MERIS fused images for land-cover mapping vegetation status assessment in heterogeneous landscapes

    NARCIS (Netherlands)

    Zurita Milla, R.; Clevers, J.G.P.W.; Gijsel, J.A.E.; Schaepman, M.E.

    2011-01-01

    In this paper we evaluate the potential of ENVISAT–Medium Resolution Imaging Spectrometer (MERIS) fused images for land-cover mapping and vegetation status assessment in heterogeneous landscapes. A series of MERIS fused images (15 spectral bands; 25 m pixel size) is created using the linear mixing m

  13. Critical evaluations of vegetation cover measurement techniques: a response to Thacker et al. (2015)

    Science.gov (United States)

    Comparison studies are necessary to reconcile methods that have arisen among disparate rangeland monitoring programs. However, Thacker et al.'s study comparing Daubenmire frame (DF) and line-point intercept (LPI) methods for estimating vegetation cover ignores definitional differences between what t...

  14. Analysis of Vegetative on Six Different Landfill Cover Profiles in an Arid Environment.

    Energy Technology Data Exchange (ETDEWEB)

    Dwyer, Stephen F.; McClellan, Yvonne; Reavis, Bruce A.; Dwyer, Brian P.; Newman, Gretchen; Wolters, Gale

    2005-05-01

    A large-scale field demonstration comparing final landfill cover designs was constructed and monitored at Sandia National Laboratories in Albuquerque, New Mexico. Two conventional designs (a RCRA Subtitle 'D' Soil Cover and a RCRA Subtitle 'C' Compacted Clay Cover) were constructed side-by-side with four alternative cover test plots designed for arid environments. The demonstration was intended to evaluate the various cover designs based on their respective water balance performance, ease and reliability of construction, and cost. A portion of this project involves the characterization of vegetation establishment and growth on the landfill covers. The various prototype landfill covers were expected to have varying flux rates (Dwyer et al 2000). The landfill covers were further expected to influence vegetation establishment and growth, which may impact site erosion potential and long-term site integrity. Objectives of this phase were to quantify the types of plants occupying each site, the percentage of ground covered by these plants, the density (number of plants per unit area) of plants, and the plant biomass production. The results of this vegetation analysis are presented in this report.3 DRAFT07/06/14AcknowledgementsWe would like to thank all technical and support staff from Sandia and the USDA Forest Service's Rocky Mountain Station not included in the authors' list of this document for their valuable contributions to this research. We would also like to acknowledge the Department of Energy's Subsurface Contaminants Focus Area for funding this work.4

  15. Complex responses of spring alpine vegetation phenology to snow cover dynamics over the Tibetan Plateau, China.

    Science.gov (United States)

    Wang, Siyuan; Wang, Xiaoyue; Chen, Guangsheng; Yang, Qichun; Wang, Bin; Ma, Yuanxu; Shen, Ming

    2017-09-01

    Snow cover dynamics are considered to play a key role on spring phenological shifts in the high-latitude, so investigating responses of spring phenology to snow cover dynamics is becoming an increasingly important way to identify and predict global ecosystem dynamics. In this study, we quantified the temporal trends and spatial variations of spring phenology and snow cover across the Tibetan Plateau by calibrating and analyzing time series of the NOAA AVHRR-derived normalized difference vegetation index (NDVI) during 1983-2012. We also examined how snow cover dynamics affect the spatio-temporal pattern of spring alpine vegetation phenology over the plateau. Our results indicated that 52.21% of the plateau experienced a significant advancing trend in the beginning of vegetation growing season (BGS) and 34.30% exhibited a delaying trend. Accordingly, the snow cover duration days (SCD) and snow cover melt date (SCM) showed similar patterns with a decreasing trend in the west and an increasing trend in the southeast, but the start date of snow cover (SCS) showed an opposite pattern. Meanwhile, the spatial patterns of the BGS, SCD, SCS and SCM varied in accordance with the gradients of temperature, precipitation and topography across the plateau. The response relationship of spring phenology to snow cover dynamics varied within different climate, terrain and alpine plant community zones, and the spatio-temporal response patterns were primarily controlled by the long-term local heat-water conditions and topographic conditions. Moreover, temperature and precipitation played a profound impact on diverse responses of spring phenology to snow cover dynamics. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Vegetation and Variable Snow Cover: Spatial Patterns of Shrubland, and Grassland Snow

    Science.gov (United States)

    Liston, G. E.; Hiemstra, C. A.; Strack, J. E.

    2003-12-01

    Regions that experience long winters with snowfall and high winds frequently exhibit heterogeneous snow distribution patterns that arise from interactions among snow, wind, topography, and vegetation. Variable snow cover and resultant heterogeneities in albedo and growing season length can affect local weather patterns and energy budgets, and produce spatially co-variable ecosystem properties. While snow influences local atmospheric processes and ecosystems, an important and underappreciated feedback exists between vegetation and snow cover. Plant size, canopy density, and rigidity determine how much snow accumulates on the lee side of individual plants (e.g., shrubland vs. grassland). In addition, the canopy can also influence how much energy reaches the snowpack, thereby hindering or accelerating snowmelt. An overhanging canopy reduces incoming solar radiation while providing a source of turbulent sensible and longwave radiative energy. Historically, most snow vegetation interaction studies have been limited to areas that experience an abundance of snow (e.g., mountainous areas) where trees have a large influence on seasonal snow-cover. In contrast, snow cover patterns associated with shrublands and grasslands have received little attention, despite covering vast expanses (53%) of the seasonally snow-covered globe. In this study, snow depths were measured every two weeks from December through March in a small, 0.25 km2 study area located in North Park, Colorado. The study area possesses little topographic relief and consists of shrub patches, dominated by greasewood (Sarcobatus vermiculatus) and sagebrush (Artemisia tridentata), embedded in a matrix of graminoids (sedges, rushes, and grasses). Snow cover patterns and spatial statistics were dramatically different in graminoid-dominated cover compared with shrub cover. The graminoid snow cover was thinner, less variable, and more ephemeral than the shrub snow pack. Snow was readily eroded by wind from graminoid

  17. Urban Vegetative Cover Fragmentation in the U.S.: Associations With Physical Activity and BMI.

    Science.gov (United States)

    Tsai, Wei-Lun; Floyd, Myron F; Leung, Yu-Fai; McHale, Melissa R; Reich, Brian J

    2016-04-01

    Urban vegetative cover provides a range of ecosystem services including contributions to human health and well-being. Urbanization exerts tremendous pressure on this natural resource, causing fragmentation and loss of urban greenspace. This study aimed to examine associations between vegetative cover fragmentation and physical activity and BMI at the county scale in the U.S. metropolitan statistical areas greater than 1 million in population. National Land Cover Database 2006 and Behavioral Risk Factor Surveillance System 2008 provided land cover and human health data, respectively. Analyses were performed in 2013 at the county scale where the health data were reported. Spearman rank correlation and stepwise and hierarchical regression models were applied to estimate relationships between land cover and health variables. After controlling for median household income and race, greater forest edge density (β=0.272, psize of herbaceous patches (β=0.261, p<0.01) were associated with a higher percentage of participation in physical activity within counties. More connections between forest and developed area (β=0.37, p<0.01) and greater edge density of shrubland (β=0.646, p<0.001) were positively associated with a higher percentage of normal BMI (<25) within counties. Forest land cover and some degree of fragmentation are associated with population physical activity. Future studies should examine how built environments and varying land cover configurations influence physical activity and weight status. Copyright © 2016 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  18. Comparison of Vegetation Indices and Red-edge Parameters for Estimating Grassland Cover from Canopy Reflectance Data

    Institute of Scientific and Technical Information of China (English)

    Zhan-Yu Liu; Jing-Feng Huang; Xin-Hong Wu; Yong-Ping Dong

    2007-01-01

    There has been a great deal of interests in the estimation of grassland biophysical parameters such as percentage of vegetation cover (PVC), aboveground biomass, and leaf-area index with remote sensing data at the canopy scale. In this paper, the percentage of vegetation cover was estimated from vegetation indices using Moderate Resolution Imaging Spectroradiometer (MODIS) data and red-edge parameters through the first derivative spectrum from in situ hypserspectral reflectance data. Hyperspectral reflectance measurements were made on grasslands in Inner Mongolia, China, using an Analytical Spectral Devices spectroradiometer. Vegetation indices such as the difference, simple ratio, normalized difference,renormalized difference, soil-adjusted and modified soil-adjusted vegetation indices (DVI, RVI, NDVI, RDVI,SAVIL = 0.5 and MSAVI2) were calculated from the hyperspectral reflectance of various vegetation covers. The percentage of vegetation cover was estimated using an unsupervised spectral-contextual classifier automatically. Relationships between percentage of vegetation cover and various vegetation indices and red-edge parameters were compared using a linear and second-order polynomial regression. Our analysis indicated that MSAVI2 and RVI yielded more accurate estimations for a wide range of vegetation cover thanother vegetation indices and red-edge parameters for the linear and second-order polynomial regression,respectively.

  19. Comparison of Unmanned Aerial Vehicle Platforms for Assessing Vegetation Cover in Sagebrush Steppe Ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Robert P. Breckenridge; Maxine Dakins; Stephen Bunting; Jerry Harbour; Sera White

    2011-09-01

    In this study, the use of unmanned aerial vehicles (UAVs) as a quick and safe method for monitoring biotic resources was evaluated. Vegetation cover and the amount of bare ground are important factors in understanding the sustainability of many ecosystems and assessment of rangeland health. Methods that improve speed and cost efficiency could greatly improve how biotic resources are monitored on western lands. Sagebrush steppe ecosystems provide important habitat for a variety of species (including sage grouse and pygmy rabbit). Improved methods are needed to support monitoring these habitats because there are not enough resource specialists or funds available for comprehensive ground evaluations. In this project, two UAV platforms, fixed wing and helicopter, were used to collect still-frame imagery to assess vegetation cover in sagebrush steppe ecosystems. This paper discusses the process for collecting and analyzing imagery from the UAVs to (1) estimate percent cover for six different vegetation types (shrub, dead shrub, grass, forb, litter, and bare ground) and (2) locate sage grouse using representative decoys. The field plots were located on the Idaho National Engineering (INL) site west of Idaho Falls, Idaho, in areas with varying amounts and types of vegetation cover. A software program called SamplePoint was used along with visual inspection to evaluate percent cover for the six cover types. Results were compared against standard field measurements to assess accuracy. The comparison of fixed-wing and helicopter UAV technology against field estimates shows good agreement for the measurement of bare ground. This study shows that if a high degree of detail and data accuracy is desired, then a helicopter UAV may be a good platform to use. If the data collection objective is to assess broad-scale landscape level changes, then the collection of imagery with a fixed-wing system is probably more appropriate.

  20. The influence of badland surfaces and erosion processes on vegetation cover

    Science.gov (United States)

    Hardenbicker, Ulrike; Matheis, Sarah

    2014-05-01

    To assess the links between badland geomorphology and vegetation cover, we used detailed mapping in the Avonlea badlands, 60 km southwest of Regina, Saskatchewan Canada. Three badlands surfaces are typical in the study area: a basal pediment surface, a mid-slope of bentonitic mudstone with typical popcorn surface, and an upper slope with mud-cemented sandstone. Badland development was triggered by rapid post Pleistocene incision of a meltwater channel in Upper Cretaceous marine and lagoonal sediments. After surveying and mapping of a test area, sediment samples were taken to analyze geophysical parameters. A detailed geomorphic map and vegetation map (1:1000) were compared and analyzed in order to determine the geomorphic environment for plant colonization. The shrink-swell capacity of the bentonitic bedrock, slaking potential and dispersivity are controlled by soil texture, clay mineralogy and chemistry, strongly influencing the timing and location of runoff and the relative significance of surface and subsurface erosional processes. The absence of shrink-swell cracking of the alluvial surfaces of the pediments indicates a low infiltration capacity and sheetflow. The compact lithology of the sandstone is responsible for its low permeability and high runoff coefficient. Slope drainage of steep sandstone slopes is routed through a deep corrasional pipe network. Silver sagebrush (Artemisia cana) is the only species growing on the popcorn surface of the mudrock, which is in large parts vegetation free. The basal pediment shows a distinct 2 m band surrounding the mudrock outcrop without vegetation as a result of high sedimentation rate due to slope wash. Otherwise the typical pioneer vegetation of this basal pediment are grasses. In the transition zone below the steep sandstone cliffs and above the gentle bentonitic mudrock surfaces patches of short-grass vegetation are found, marking slumped blocks with intact vegetation and soil cover. These patches are surrounded by

  1. Is ground cover vegetation an effective biological control enhancement strategy against olive pests?

    Directory of Open Access Journals (Sweden)

    Daniel Paredes

    Full Text Available Ground cover vegetation is often added or allowed to generate to promote conservation biological control, especially in perennial crops. Nevertheless, there is inconsistent evidence of its effectiveness, with studies reporting positive, nil or negative effects on pest control. This might arise from differences between studies at the local scale (e.g. orchard management and land use history, the landscape context (e.g. presence of patches of natural or semi-natural vegetation near the focal orchard, or regional factors, particularly climate in the year of the study. Here we present the findings from a long-term regional monitoring program conducted on four pest species (Bactrocera oleae, Prays oleae, Euphyllura olivina, Saissetia oleae in 2,528 olive groves in Andalusia (Spain from 2006 to 2012. Generalized linear mixed effect models were used to analyze the effect of ground cover on different response variables related to pest abundance, while accounting for variability at the local, landscape and regional scales. There were small and inconsistent effects of ground cover on the abundance of pests whilst local, landscape and regional variability explained a large proportion of the variability in pest response variables. This highlights the importance of local and landscape-related variables in biological control and the potential effects that might emerge from their interaction with practices, such as groundcover vegetation, implemented to promote natural enemy activity. The study points to perennial vegetation close to the focal crop as a promising alternative strategy for conservation biological control that should receive more attention.

  2. Is ground cover vegetation an effective biological control enhancement strategy against olive pests?

    Science.gov (United States)

    Paredes, Daniel; Cayuela, Luis; Gurr, Geoff M; Campos, Mercedes

    2015-01-01

    Ground cover vegetation is often added or allowed to generate to promote conservation biological control, especially in perennial crops. Nevertheless, there is inconsistent evidence of its effectiveness, with studies reporting positive, nil or negative effects on pest control. This might arise from differences between studies at the local scale (e.g. orchard management and land use history), the landscape context (e.g. presence of patches of natural or semi-natural vegetation near the focal orchard), or regional factors, particularly climate in the year of the study. Here we present the findings from a long-term regional monitoring program conducted on four pest species (Bactrocera oleae, Prays oleae, Euphyllura olivina, Saissetia oleae) in 2,528 olive groves in Andalusia (Spain) from 2006 to 2012. Generalized linear mixed effect models were used to analyze the effect of ground cover on different response variables related to pest abundance, while accounting for variability at the local, landscape and regional scales. There were small and inconsistent effects of ground cover on the abundance of pests whilst local, landscape and regional variability explained a large proportion of the variability in pest response variables. This highlights the importance of local and landscape-related variables in biological control and the potential effects that might emerge from their interaction with practices, such as groundcover vegetation, implemented to promote natural enemy activity. The study points to perennial vegetation close to the focal crop as a promising alternative strategy for conservation biological control that should receive more attention.

  3. Influence of vegetations and snow cover on sand-dust events in the west of China

    Institute of Scientific and Technical Information of China (English)

    XU Xingkui; CHEN Hong

    2006-01-01

    By using Normalized Difference Vegetation Index (NDVI) with the resolution of 80km(80km, satellite remote sensing data, derived from the National Oceanic and Atmospheric Administration (NOAA) and Empirical Orthogonal Function (EOF) analysis showed that surface vegetation cover in large areas of northwest China took on a significantly increasing trend between 1982 and 1994, and decreased after 1995. The first two temporal coefficients corresponding to respective eigenvector can reflect the annual change of vegetation exactly in the west of China. The correlation analysis between NDVI and the frequency of sand storms, blowing sand and floating dust illuminate that annual change of vegetation is one of the most important factors affecting disaster weather, such as sand-dust events. Meanwhile, correlation analyses also demonstrate that the snowfall in the part of western China plays an important role in sand-dust events. In this study, the influence of vegetation and snow cover in the west of China on the frequency of sand-dust events is revealed directly in virtue of remote sensing data, weather observational data and statistical methods.

  4. Remote Sensing of Fractional Green Vegetation Cover Using Spatially-Interpolated Endmembers

    Directory of Open Access Journals (Sweden)

    Ryutaro Tateishi

    2012-09-01

    Full Text Available Fractional green vegetation cover (FVC is a useful parameter for many environmental and climate-related applications. A common approach for estimating FVC involves the linear unmixing of two spectral endmembers in a remote sensing image; bare soil and green vegetation. The spectral properties of these two endmembers are typically determined based on field measurements, estimated using additional data sources (e.g., soil databases or land cover maps, or extracted directly from the imagery. Most FVC estimation approaches do not consider that the spectral properties of endmembers may vary across space. However, due to local differences in climate, soil type, vegetation species, etc., the spectral characteristics of soil and green vegetation may exhibit positive spatial autocorrelation. When this is the case, it may be useful to take these local variations into account for estimating FVC. In this study, spatial interpolation (Inverse Distance Weighting and Ordinary Kriging was used to predict variations in the spectral characteristics of bare soil and green vegetation across space. When the spatially-interpolated values were used in place of scene-invariant endmember values to estimate FVC in an Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER image, the accuracy of FVC estimates increased, providing evidence that it may be useful to consider the effects of spatial autocorrelation for spectral mixture analysis.

  5. Phenopix: a R package to process digital images of a vegetation cover

    Science.gov (United States)

    Filippa, Gianluca; Cremonese, Edoardo; Migliavacca, Mirco; Galvagno, Marta; Morra di Cella, Umberto; Richardson, Andrew

    2015-04-01

    Plant phenology is a globally recognized indicator of the effects of climate change on the terrestrial biosphere. Accordingly, new tools to automatically track the seasonal development of a vegetation cover are becoming available and more and more deployed. Among them, near-continuous digital images are being collected in several networks in the US, Europe, Asia and Australia in a range of different ecosystems, including agricultural lands, deciduous and evergreen forests, and grasslands. The growing scientific interest in vegetation image analysis highlights the need of easy to use, flexible and standardized processing techniques. In this contribution we illustrate a new open source package called "phenopix" written in R language that allows to process images of a vegetation cover. The main features include: (i) define of one or more areas of interest on an image and process pixel information within them, (ii) compute vegetation indexes based on red green and blue channels, (iii) fit a curve to the seasonal trajectory of vegetation indexes and extract relevant dates (aka thresholds) on the seasonal trajectory; (iv) analyze image pixels separately to extract spatially explicit phenological information. The utilities of the package will be illustrated in detail for two subalpine sites, a grassland and a larch stand at about 2000 m in the Italian Western Alps. The phenopix package is a cost free and easy-to-use tool that allows to process digital images of a vegetation cover in a standardized, flexible and reproducible way. The software is available for download at the R forge web site (r-forge.r-project.org/projects/phenopix/).

  6. Modelling high arctic percent vegetation cover using field digital images and high resolution satellite data

    Science.gov (United States)

    Liu, Nanfeng; Treitz, Paul

    2016-10-01

    In this study, digital images collected at a study site in the Canadian High Arctic were processed and classified to examine the spatial-temporal patterns of percent vegetation cover (PVC). To obtain the PVC of different plant functional groups (i.e., forbs, graminoids/sedges and mosses), field near infrared-green-blue (NGB) digital images were classified using an object-based image analysis (OBIA) approach. The PVC analyses comparing different vegetation types confirmed: (i) the polar semi-desert exhibited the lowest PVC with a large proportion of bare soil/rock cover; (ii) the mesic tundra cover consisted of approximately 60% mosses; and (iii) the wet sedge consisted almost exclusively of graminoids and sedges. As expected, the PVC and green normalized difference vegetation index (GNDVI; (RNIR - RGreen)/(RNIR + RGreen)), derived from field NGB digital images, increased during the summer growing season for each vegetation type: i.e., ∼5% (0.01) for polar semi-desert; ∼10% (0.04) for mesic tundra; and ∼12% (0.03) for wet sedge respectively. PVC derived from field images was found to be strongly correlated with WorldView-2 derived normalized difference spectral indices (NDSI; (Rx - Ry)/(Rx + Ry)), where Rx is the reflectance of the red edge (724.1 nm) or near infrared (832.9 nm and 949.3 nm) bands; Ry is the reflectance of the yellow (607.7 nm) or red (658.8 nm) bands with R2's ranging from 0.74 to 0.81. NDSIs that incorporated the yellow band (607.7 nm) performed slightly better than the NDSIs without, indicating that this band may be more useful for investigating Arctic vegetation that often includes large proportions of senescent vegetation throughout the growing season.

  7. Calculation set for design and optimization of vegetative soil covers Sandia National Laboratories, Albuquerque, New Mexico.

    Energy Technology Data Exchange (ETDEWEB)

    Peace, Gerald L.; Goering, Timothy James (GRAM, Inc., Albuquerque, NM)

    2005-02-01

    This study demonstrates that containment of municipal and hazardous waste in arid and semiarid environments can be accomplished effectively without traditional, synthetic materials and complex, multi-layer systems. This research demonstrates that closure covers combining layers of natural soil, native plant species, and climatic conditions to form a sustainable, functioning ecosystem will meet the technical equivalency criteria prescribed by the U. S. Environmental Protection Agency. In this study, percolation through a natural analogue and an engineered cover is simulated using the one-dimensional, numerical code UNSAT-H. UNSAT-H is a Richards. equation-based model that simulates soil water infiltration, unsaturated flow, redistribution, evaporation, plant transpiration, and deep percolation. This study incorporates conservative, site-specific soil hydraulic and vegetation parameters. Historical meteorological data are used to simulate percolation through the natural analogue and an engineered cover, with and without vegetation. This study indicates that a 3-foot (ft) cover in arid and semiarid environments is the minimum design thickness necessary to meet the U. S. Environmental Protection Agency-prescribed technical equivalency criteria of 31.5 millimeters/year and 1 x 10{sup -7} centimeters/second for net annual percolation and average flux, respectively. Increasing cover thickness to 4 or 5 ft results in limited additional improvement in cover performance.

  8. Changes in climatic conditions, vegetation cover and erosion during the Holocene in southeast Spain

    Energy Technology Data Exchange (ETDEWEB)

    Bellin, N.; Vanacker, V.

    2009-07-01

    The present-day landscape in Southeast Spain is the result of a long occupation history. To have a better understanding of the impact of human societies on soil degradation, we analysed the main shifts in vegetation cover, climate and human occupation for the last 12000 years. Our analyses use recently published information from continental and marine pollen series. The data suggest that climatic factors appear to be important driving factors of vegetation degradation induced by an increased aridity that is already recorded at about 5000 years ago. (Author) 19 refs.

  9. Woody vegetation and land cover changes in the Sahel of Mali (1967-2011)

    Science.gov (United States)

    Spiekermann, Raphael; Brandt, Martin; Samimi, Cyrus

    2015-02-01

    In the past 50 years, the Sahel has experienced significant tree- and land cover changes accelerated by human expansion and prolonged droughts during the 1970s and 1980s. This study uses remote sensing techniques, supplemented by ground-truth data to compare pre-drought woody vegetation and land cover with the situation in 2011. High resolution panchromatic Corona imagery of 1967 and multi-spectral RapidEye imagery of 2011 form the basis of this regional scaled study, which is focused on the Dogon Plateau and the Seno Plain in the Sahel zone of Mali. Object-based feature extraction and classifications are used to analyze the datasets and map land cover and woody vegetation changes over 44 years. Interviews add information about changes in species compositions. Results show a significant increase of cultivated land, a reduction of dense natural vegetation as well as an increase of trees on farmer's fields. Mean woody cover decreased in the plains (-4%) but is stable on the plateau (+1%) although stark spatial discrepancies exist. Species decline and encroachment of degraded land are observed. However, the direction of change is not always negative and a variety of spatial variations are shown. Although the impact of climate is obvious, we demonstrate that anthropogenic activities have been the main drivers of change.

  10. Consequences of changes in vegetation and snow cover for climate feedbacks in Alaska and northwest Canada

    Science.gov (United States)

    Euskirchen, E. S.; Bennett, A. P.; Breen, A. L.; Genet, H.; Lindgren, M. A.; Kurkowski, T. A.; McGuire, A. D.; Rupp, T. S.

    2016-10-01

    Changes in vegetation and snow cover may lead to feedbacks to climate through changes in surface albedo and energy fluxes between the land and atmosphere. In addition to these biogeophysical feedbacks, biogeochemical feedbacks associated with changes in carbon (C) storage in the vegetation and soils may also influence climate. Here, using a transient biogeographic model (ALFRESCO) and an ecosystem model (DOS-TEM), we quantified the biogeophysical feedbacks due to changes in vegetation and snow cover across continuous permafrost to non-permafrost ecosystems in Alaska and northwest Canada. We also computed the changes in carbon storage in this region to provide a general assessment of the direction of the biogeochemical feedback. We considered four ecoregions, or Landscape Conservations Cooperatives (LCCs; including the Arctic, North Pacific, Western Alaska, and Northwest Boreal). We examined the 90 year period from 2010 to 2099 using one future emission scenario (A1B), under outputs from two general circulation models (MPI-ECHAM5 and CCCMA-CGCM3.1). We found that changes in snow cover duration, including both the timing of snowmelt in the spring and snow return in the fall, provided the dominant positive biogeophysical feedback to climate across all LCCs, and was greater for the ECHAM (+3.1 W m-2 decade-1 regionally) compared to the CCCMA (+1.3 W m-2 decade-1 regionally) scenario due to an increase in loss of snow cover in the ECHAM scenario. The greatest overall negative feedback to climate from changes in vegetation cover was due to fire in spruce forests in the Northwest Boreal LCC and fire in shrub tundra in the Western LCC (-0.2 to -0.3 W m-2 decade-1). With the larger positive feedbacks associated with reductions in snow cover compared to the smaller negative feedbacks associated with shifts in vegetation, the feedback to climate warming was positive (total feedback of +2.7 W m-2 decade regionally in the ECHAM scenario compared to +0.76 W m-2 decade regionally

  11. Status of vegetation cover after 25 years since the last wildfire (Río Verde, Spain)

    Science.gov (United States)

    Martinez-Murillo, Juan F.; Remond, Ricardo; Ruiz-Sinoga, José D.

    2016-04-01

    Climatic conditions play an important role in the post-fire vegetation recovery as well as other factors like topography, soil, and pre and post-fire land use (Shakesby, 2011; Robichaud et al., 2013). This study deals with the characterization of the vegetation cover status in an area affected by a wildfire 25 years ago. Namely, the objectives are to: i) compare the current and previous vegetation cover to wildfire; and ii) evaluate whether the current vegetation has recovered the previous cover to wildfire. The study area is mainly located in the Rio Verde watershed (Sierra de las Nieves, South of Spain). It corresponds to an area affected by a wildfire in August 8th, 1991. The burned area was equal to 8,156 ha. The burn severity was spatially very high. The main geographic features of the burned area are: mountainous topography (altitudes ranging from 250 m to 1700 m; slope gradient >25%; exposure mainly southfacing); igneous (peridotites), metamorphic (gneiss) and calcareous rocks (limestones); and predominant forest land use (Pinus pinaster sp. woodlands, 10%; pinus opened forest + shrubland, 40%; shrubland, 35%; and bare soil + grassland, 15%). Remote sensing techniques and GIS analysis has been applied to achieve the objectives. Landsat 5 and Landsat 8 images were used: July 13th, 1991 and July 1st, 2013, for the previous wildfire situation and 22-years after, respectively. The 1990 CORINE land cover was also considered to map 1991 land uses prior the wildfire. The Andalucía Regional Government wildfire historic records were used to select the burned area and its geographical limit. 1991 and 2013 land cover maps were obtained by means of object-oriented classifications. Also, NDVI index were calculated and mapped for both years in order to compare the status of vegetation cover. According to the results, the combination of remote sensing and GIS analysis let map the most recovered areas affected by the wildfire in 1991. The vegetation indexes indicated that

  12. Modeling the effects of vegetation on methane oxidation and emissions through soil landfill final covers across different climates.

    Science.gov (United States)

    Abichou, Tarek; Kormi, Tarek; Yuan, Lei; Johnson, Terry; Francisco, Escobar

    2015-02-01

    Plant roots are reported to enhance the aeration of soil by creating secondary macropores which improve the diffusion of oxygen into soil as well as the supply of methane to bacteria. Therefore, methane oxidation can be improved considerably by the soil structuring processes of vegetation, along with the increase of organic biomass in the soil associated with plant roots. This study consisted of using a numerical model that combines flow of water and heat with gas transport and oxidation in soils, to simulate methane emission and oxidation through simulated vegetated and non-vegetated landfill covers under different climatic conditions. Different simulations were performed using different methane loading flux (5-200 g m(-2) d(-1)) as the bottom boundary. The lowest modeled surface emissions were always obtained with vegetated soil covers for all simulated climates. The largest differences in simulated surface emissions between the vegetated and non-vegetated scenarios occur during the growing season. Higher average yearly percent oxidation was obtained in simulations with vegetated soil covers as compared to non-vegetated scenario. The modeled effects of vegetation on methane surface emissions and percent oxidation were attributed to two separate mechanisms: (1) increase in methane oxidation associated with the change of the physical properties of the upper vegetative layer and (2) increase in organic matter associated with vegetated soil layers. Finally, correlations between percent oxidation and methane loading into simulated vegetated and non-vegetated covers were proposed to allow decision makers to compare vegetated versus non-vegetated soil landfill covers. These results were obtained using a modeling study with several simplifying assumptions that do not capture the complexities of vegetated soils under field conditions.

  13. Land Use and Land Cover - LAND_COVER_PRESETTLEMENT_IDNR_IN: Generalized Presettlement Vegetation Types of Indiana, Circa 1820 (Indiana Department of Natural Resources, Polygon Shapefile)

    Data.gov (United States)

    NSGIC State | GIS Inventory — LAND_COVER_PRESETTLEMENT_IDNR_IN.SHP is a polygon shapefile showing generalized presettlement vegetation types of Indiana, circa 1820. The work was based on original...

  14. Artichoke (Cynara scolymus L. as cash-cover crop in an organic vegetable system

    Directory of Open Access Journals (Sweden)

    Anna LENZI

    2015-11-01

    Full Text Available In organic vegetable systems green manure crops play an important role as a nitrogen source, but they cover the soil for several months without producing a direct income. Globe artichoke (Cynara scolymus L. provides both heads to be harvested and particularly abundant plant residues to be possibly incorporated into the soil, so it may play a double role of cash and cover crop. This paper describes an on-farm study in which seed-propagated artichoke, cultivated as an annual crop, preceded zucchini squash and lettuce cultivated in sequence within a vegetable organic system. Artichoke produced about 7 t ha-1 of saleable heads and left, after harvest, 50.3 t ha-1 of fresh biomass usable as green manure. Zucchini squash and lettuce following artichoke showed a significant increase in yield when artichoke residues were incorporated into the soil. Furthermore, a residual positive effect of green manure on soil fertility was detected after lettuce harvest. 

  15. Tree cover bistability in the MPI Earth system model due to fire-vegetation feedback

    Science.gov (United States)

    Lasslop, Gitta; Brovkin, Victor; Kloster, Silvia; Reick, Christian

    2015-04-01

    The global distribution of tree cover is mainly limited by precipitation and temperature. Within tropical ecosystems different tree cover values have been observed in regions with similar climate. Satellite data even revealed a lack of ecosystems with tree coverage around 60% and dominant tree covers of 20% and 80%. Conceptual models have been used to explain this tree cover distribution and base it on a bistability in tree cover caused by fire-vegetation interactions or competition between trees and grasses. Some ecological models also show this property of multiple stable tree covers, but it remains unclear which mechanism is the cause for this behaviour. Vegetation models used in climate simulations usually use simple approaches and were criticised to neglect such ecological theories and misrepresent tropical tree cover distribution and dynamics. Here we show that including the process based fire model SPITFIRE generated a bistability in tree cover in the land surface model JSBACH. Previous model versions showed only one stable tree cover state. Using a conceptual model we can show that a bistability can occur due to a feedback between grasses and fire. Grasses and trees are represented in the model based on plant functional types. With respect to fire the main difference between grasses and trees is the fuel characteristics. Grass fuels are smaller in size, and have a higher surface area to volume ratio. These grass fuels dry faster increasing their flammability which leads to a higher fire rate of spread. Trees are characterized by coarse fuels, which are less likely to ignite and rather suppress fire. Therefore a higher fraction of grasses promotes fire, fire kills trees and following a fire, grasses establish faster. This feedback can stabilize ecosystems with low tree cover in a low tree cover state and systems with high tree cover in a high tree cover state. In previous model versions this feedback was absent. Based on the new JSBACH model driven with

  16. Vegetation resources inventory of southwest Alaska: development and application of an innovative, extensive sampling design.

    Science.gov (United States)

    Willem W.S. van Hees

    1999-01-01

    An assessment of the vegetation resources of southwest Alaska was made by using an inventory design developed by the Pacific Northwest Research Station. Satellite imagery (LANDSAT MSS), high-altitude aerial photography, and ground sampling were the major components of the design. Estimates of area for all land cover classes in the southwest region were produced....

  17. Effect of management systems and cover crops on organic matter dynamics of soil under vegetables

    Directory of Open Access Journals (Sweden)

    Rodrigo Fernandes de Souza

    2014-06-01

    Full Text Available Vegetable production in conservation tillage has increased in Brazil, with positive effects on the soil quality. Since management systems alter the quantity and quality of organic matter, this study evaluated the influence of different management systems and cover crops on the organic matter dynamics of a dystrophic Red Latosol under vegetables. The treatments consisted of the combination of three soil tillage systems: no-tillage (NT, reduced tillage (RT and conventional tillage (CT and of two cover crops: maize monoculture and maize-mucuna intercrop. Vegetables were grown in the winter and the cover crops in the summer for straw production. The experiment was arranged in a randomized block design with four replications. Soil samples were collected between the crop rows in three layers (0.0-0.05, 0.05-0.10, and 0.10-0.30 m twice: in October, before planting cover crops for straw, and in July, during vegetable cultivation. The total organic carbon (TOC, microbial biomass carbon (MBC, oxidizable fractions, and the carbon fractions fulvic acid (C FA, humic acid (C HA and humin (C HUM were determined. The main changes in these properties occurred in the upper layers (0.0-0.05 and 0.05-0.10 m where, in general, TOC levels were highest in NT with maize straw. The MBC levels were lowest in CT systems, indicating sensitivity to soil disturbance. Under mucuna, the levels of C HA were lower in RT than NT systems, while the C FA levels were lower in RT than CT. For vegetable production, the C HUM values were lowest in the 0.05-0.10 m layer under CT. With regard to the oxidizable fractions, the tillage systems differed only in the most labile C fractions, with higher levels in NT than CT in the 0.0-0.05 m layer in both summer and winter, with no differences between these systems in the other layers. The cabbage yield was not influenced by the soil management system, but benefited from the mulch production of the preceding maize-mucuna intercrop as cover

  18. Comparison Between Fractional Vegetation Cover Retrievals from Vegetation Indices and Spectral Mixture Analysis: Case Study of PROBA/CHRIS Data Over an Agricultural Area

    OpenAIRE

    Pablo Martinez; José Moreno; Luis Guanter; Antonio Plaza; José A Sobrino; Jiménez-Muñoz, Juan C.

    2009-01-01

    Abstract: In this paper we compare two different methodologies for Fractional Vegetation Cover (FVC) retrieval from Compact High Resolution Imaging Spectrometer (CHRIS) data onboard the European Space Agency (ESA) Project for On-Board Autonomy (PROBA) platform. The first methodology is based on empirical approaches using Vegetation Indices (VIs), in particular the Normalized Difference Vegetation Index (NDVI) and the Variable Atmospherically Resistant Index (VARI). The second methodology is b...

  19. Spreading topsoil encourages ecological restoration on embankments: soil fertility, microbial activity and vegetation cover.

    Science.gov (United States)

    Rivera, Desirée; Mejías, Violeta; Jáuregui, Berta M; Costa-Tenorio, Marga; López-Archilla, Ana Isabel; Peco, Begoña

    2014-01-01

    The construction of linear transport infrastructure has severe effects on ecosystem functions and properties, and the restoration of the associated roadslopes contributes to reduce its impact. This restoration is usually approached from the perspective of plant cover regeneration, ignoring plant-soil interactions and the consequences for plant growth. The addition of a 30 cm layer of topsoil is a common practice in roadslope restoration projects to increase vegetation recovery. However topsoil is a scarce resource. This study assesses the effects of topsoil spreading and its depth (10 to 30 cm) on two surrogates of microbial activity (β-glucosidase and phosphatase enzymes activity and soil respiration), and on plant cover, plant species richness and floristic composition of embankment vegetation. The study also evaluates the differences in selected physic-chemical properties related to soil fertility between topsoil and the original embankment substrate. Topsoil was found to have higher values of organic matter (11%), nitrogen (44%), assimilable phosphorous (50%) and silt content (54%) than the original embankment substrate. The topsoil spreading treatment increased microbial activity, and its application increased β-glucosidase activity (45%), phosphatase activity (57%) and soil respiration (60%). Depth seemed to affect soil respiration, β-glucosidase and phosphatase activity. Topsoil application also enhanced the species richness of restored embankments in relation to controls. Nevertheless, the depth of the spread topsoil did not significantly affect the resulting plant cover, species richness or floristic composition, suggesting that both depths could have similar effects on short-term recovery of the vegetation cover. A significant implication of these results is that it permits the application of thinner topsoil layers, with major savings in this scarce resource during the subsequent slope restoration work, but the quality of topsoil relative to the

  20. Spreading topsoil encourages ecological restoration on embankments: soil fertility, microbial activity and vegetation cover.

    Directory of Open Access Journals (Sweden)

    Desirée Rivera

    Full Text Available The construction of linear transport infrastructure has severe effects on ecosystem functions and properties, and the restoration of the associated roadslopes contributes to reduce its impact. This restoration is usually approached from the perspective of plant cover regeneration, ignoring plant-soil interactions and the consequences for plant growth. The addition of a 30 cm layer of topsoil is a common practice in roadslope restoration projects to increase vegetation recovery. However topsoil is a scarce resource. This study assesses the effects of topsoil spreading and its depth (10 to 30 cm on two surrogates of microbial activity (β-glucosidase and phosphatase enzymes activity and soil respiration, and on plant cover, plant species richness and floristic composition of embankment vegetation. The study also evaluates the differences in selected physic-chemical properties related to soil fertility between topsoil and the original embankment substrate. Topsoil was found to have higher values of organic matter (11%, nitrogen (44%, assimilable phosphorous (50% and silt content (54% than the original embankment substrate. The topsoil spreading treatment increased microbial activity, and its application increased β-glucosidase activity (45%, phosphatase activity (57% and soil respiration (60%. Depth seemed to affect soil respiration, β-glucosidase and phosphatase activity. Topsoil application also enhanced the species richness of restored embankments in relation to controls. Nevertheless, the depth of the spread topsoil did not significantly affect the resulting plant cover, species richness or floristic composition, suggesting that both depths could have similar effects on short-term recovery of the vegetation cover. A significant implication of these results is that it permits the application of thinner topsoil layers, with major savings in this scarce resource during the subsequent slope restoration work, but the quality of topsoil relative to

  1. Assesment of Vegetation Cover Status in Dry Lands of The Sudan Using Social and Terrestrial Data

    Directory of Open Access Journals (Sweden)

    Mohammed Hamed Mohammed

    2016-11-01

    Full Text Available The current study was conducted in 2015 in Bara Locality, North Kordofan, Sudan. The study area has experienced recurrent drought spells since 1970s of the past century. The main objective of this study was to assess and map the vegetation cover in the area using social, terrestrial and remotely sensed data. To accomplish the above mentioned objective, the study was based on qualitative and quantitative data. In qualitative data, household survey was conducted in which 100 respondents were randomly interviewed. Quantitative data was collected using terrestrial inventory and satellite imageries. In terrestrial inventory, 22 ground control points (GCPs were randomly registered using GPS in order to get general overview of the land cover of the study area. In each GCP, tree species by number was inventoried within an area of 1 ha. Remote sensing data, covering the target study area, were acquainted using LANDSAT5 imageries (2014 with spatial resolution of 30×30 m. Results of the household survey revealed that only 13 shrub/tree species mentioned by 45% of the respondents, while only 9 woody species were identified, belonging to 8 families from terrestrial inventory. The results of the household survey, 45% of the respondents, indicated that vegetation cover was very good 20 years ago. The study categorized the present land cover as woody vegetation (19%, Acacia senegal stands (5%, shrubs i.e. Leptadenia pyrotechnica and Acacia nubica (18%, small scale farms and grasses (19% and sandy soil and dunes (39%. The results of the land cover distribution indicated that vegetation cover decreased by 24% while sand/sand dunes was increased by 21% from 1985 to 2015. The study concluded that the study area is under threat of land degradation that may lead to depletion of vegetation cover and decline land productivity. Keywords: Acacia senegal, land cover, remote sensing, sand dune, Sudan.   Pengukuran Status Penutupan Vegetasi di Lahan Kering

  2. 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.

  3. Vegetative cover and PAHs accumulation in soils of urban green space.

    Science.gov (United States)

    Peng, Chi; Ouyang, Zhiyun; Wang, Meie; Chen, Weiping; Jiao, Wentao

    2012-02-01

    We investigated how urban land uses influence soil accumulation of polycyclic aromatic hydrocarbons (PAHs) in the urban green spaces composed of different vegetative cover. How did soil properties, urbanization history, and population density affect the outcomes were also considered. Soils examined were obtained at 97 green spaces inside the Beijing metropolis. PAH contents of the soils were influenced most significantly by their proximity to point source of industries such as the coal combustion installations. Beyond the influence circle of industrial emissions, land use classifications had no significant effect on the extent of PAH accumulation in soils. Instead, the nature of vegetative covers affected PAH contents of the soils. Tree-shrub-herb and woodland settings trapped more airborne PAH and soils under these vegetative patterns accumulated more PAHs than those of the grassland. Urbanization history, population density and soil properties had no apparent impact on PAHs accumulations in soils of urban green space. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

  4. The effect of vegetation cover on the formation of glide-snow avalanches

    Science.gov (United States)

    Feistl, Thomas; Bebi, Peter; Bartelt, Perry

    2014-05-01

    Glide snow avalanches release on steep, smooth slopes and can be prevented either by protection forests or by artificial defense structures. To minimize the risk for people and infrastructure, guidelines have been formulated concerning structure, height and distance between avalanche prevention bridges. These guidelines assure the major functions of the defense structures: first to prevent the release of avalanches and second to withstand the static and dynamic forces of the moving snow cover. The major functions of protection forests are generally similar and therefore guidelines on the maximum tolerable size of forest gaps exist in Switzerland. These guidelines are based on a static relationship between the pressure of the snow cover and the resistance of the defense structure and on empirical observations (forest). Whereas ground friction is only qualitatively taken into account, we assume it to play a crucial role in glide snow avalanche formation. To prove this assumption we collected data on the predominant vegetation cover of 67 release areas in the region of Davos, Switzerland. Our observations reveal a strong relationship between vegetation cover type, slope angle and slab length. We were able to quantify the Coulomb friction parameter μ by applying a physical model that accounts for the dynamic forces of the moving snow on the stauchwall, the fixed snow cover below the release area. The stauchwall resists the dynamic forces of the snow cover, until a critical strain rate is reached and then fails in brittle compression. This failure strongly depends on the friction between snow cover and soil. A typical value of μ for grassy slopes is 0.2. Snow characteristics like density are implemented in the model as constants. We compared the model results with the guidelines for defense structures and forest gap sizes and found accordance for certain friction parameter values. Forest gaps of 40 meter length and a 35° slope angle require friction values of 0

  5. Alelopatia de cultivos de cobertura vegetal sobre plantas infestantes = Allelopathy of cover crop on weed plants

    Directory of Open Access Journals (Sweden)

    Luciene Kazue Tokura

    2006-07-01

    Full Text Available O presente trabalho avaliou o potencial alelopático de cultivos de cobertura vegetal de trigo, aveia preta, milheto, nabo forrageiro e colza sobre o desenvolvimento de plantas infestantes e verificou qual das coberturas vegetais exerce maior controle sobre as mesmas. Os cultivos de cobertura vegetal foram implantados sob preparo convencional (uma aração e uma gradagem no Núcleo Experimental de Engenharia Agrícola (NEEA, da Universidade Estadual do Oeste do Paraná (Unioeste, Cascavel, Estado do Paraná. Mensalmente, realizou-se o acompanhamento e identificação das plantas infestantes emersas nas áreas de cobertura vegetal no período de agosto de 2000 a agosto de 2001. Os resultados obtidos permitiram concluir que das espécies encontradas, o capim marmelada foi o que apresentou maior potencial alelopático e a erva-de-santa-maria o menor. As coberturasvegetais que apresentaram melhor controle do total de plantas infestantes presentes na área experimental, incluindo àquelas com reconhecido potencial alelopático, foram aveia preta, colza, nabo forrageiro e milheto.This work evaluated the cover crop allelopathic potential of wheat, black oat, pearl millet, turnip and rape on the development of weed plants. It also verified which cover crop has larger control on the weed plants. The cover crop was implanted under conventional tillage (one disk plowing plus one disk harrowing in the Experimental Nucleus of Agricultural Engineering (NEEA, of the State University of the West of Paraná (Unioeste, Cascavel, Paraná State. Monthly (from August 2000 to August 2001, weed plants identification in the cover crop area was made. Results showed that from the found species, the alexander grass was the one that presented larger allelopathic potential, and, the mexican-tea was the one that presented smaller control. The vegetable coverings that presented larger control of the total of weed plants in the experimental area, including those with

  6. Unsupervised change detection in a particular vegetation land cover type using spectral angle mapper

    Science.gov (United States)

    Renza, Diego; Martinez, Estibaliz; Molina, Iñigo; Ballesteros L., Dora M.

    2017-04-01

    This paper presents a new unsupervised change detection methodology for multispectral images applied to specific land covers. The proposed method involves comparing each image against a reference spectrum, where the reference spectrum is obtained from the spectral signature of the type of coverage you want to detect. In this case the method has been tested using multispectral images (SPOT5) of the community of Madrid (Spain), and multispectral images (Quickbird) of an area over Indonesia that was impacted by the December 26, 2004 tsunami; here, the tests have focused on the detection of changes in vegetation. The image comparison is obtained by applying Spectral Angle Mapper between the reference spectrum and each multitemporal image. Then, a threshold to produce a single image of change is applied, which corresponds to the vegetation zones. The results for each multitemporal image are combined through an exclusive or (XOR) operation that selects vegetation zones that have changed over time. Finally, the derived results were compared against a supervised method based on classification with the Support Vector Machine. Furthermore, the NDVI-differencing and the Spectral Angle Mapper techniques were selected as unsupervised methods for comparison purposes. The main novelty of the method consists in the detection of changes in a specific land cover type (vegetation), therefore, for comparison purposes, the best scenario is to compare it with methods that aim to detect changes in a specific land cover type (vegetation). This is the main reason to select NDVI-based method and the post-classification method (SVM implemented in a standard software tool). To evaluate the improvements using a reference spectrum vector, the results are compared with the basic-SAM method. In SPOT5 image, the overall accuracy was 99.36% and the κ index was 90.11%; in Quickbird image, the overall accuracy was 97.5% and the κ index was 82.16%. Finally, the precision results of the method are

  7. Impact of Land Use and Vegetation Cover on Risks of Erosion in the Ourika Watershed (Morocco

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    Meliho Modeste

    2016-09-01

    Full Text Available Ourika watershed is located in mid-western Morocco, in the northwest of the High Atlas. This watershed, characterized by dramatic topography, sparse vegetative cover and friable substrates, is under increasing human pressure amplified by a variable and changing climate. The objective of this work was to map the risks of water erosion in the watershed using the RUSLE and GIS, and highlight, by mapping land uses, the role of land use and vegetation cover in the regulation of risks of erosion. The findings showed that the Ourika watershed was subject to strong climatic aggressiveness ranging from 55 to 101 MJ.mm/ha.h. Soil erodibility value ranged from 0.15 to 0.48 t.ha.h/ha.MJ.mm. Topographic factor ranged from 0 to 95. The vegetation cover factor was greater than 0.5 for 73% of the watershed area. The average soil loss obtained in the watershed was 380 t/ha/year. The results indicated that 48% of the watershed area is subject to soil loss between 50-400 t/ha/year, and 30% of the watershed area between 400 and 1000 t/ha/year. Soil loss below the tolerance level (<7 t/ha/year represented only 4% of the area. These results demonstrated the significance of erosion in the Ourika watershed. Croplands, clear forests, shrubland and nonforest empty spaces were subject to very high risk of erosion. By contrast, dense forests, moderately dense forests and arboriculture not mixed with cereal growing, protected the soil against erosion, improved physical and chemical soil characteristics, facilitated the infiltration of water into the soil and limited runoff and the risk of erosion

  8. Using vegetation cover type to predict and scale peatland methane dynamics.

    Science.gov (United States)

    McArthur, K. J.; McCalley, C. K.; Palace, M. W.; Varner, R. K.; Herrick, C.; DelGreco, J. L.

    2015-12-01

    Permafrost ecosystems contain about 50% of the global soil carbon. As these northern ecosystems experience warmer temperature, permafrost thaws and may result in an increase in atmospheric methane. We examined a thawing and discontinuous permafrost boundary at Stordalen Mire, in Northern Sweden, in an effort to better understand methane emissions. Stable isotope analysis of methane in peatland porewater can give insights into the pathway of methane production. By measuring δ13CH4 we can predict whether a system is dominated by either hydrogenotrophic or acetaclastic methane production. Currently, it is a challenge to scale these isotopic patterns, thus, atmospheric inversion models simply assume that acetoclastic production dominates. We analyzed porewater samples collected across a range of vegetation cover types for δ13CH4 using a QCL (Quantum Cascade Laser Spectrometer) in conjunction with highly accurate GPS (3-10cm) measurements and high-resolution UAV imaging. We found δ13CH4 values ranging from -88‰ to -41‰, with averages based on cover type and other vegetation features showing differences of up to -15‰. We then used a computer neural network to predict cover types across Stordalen Mire from UAV imagery based on field-based plot measurements and training samples.. This prediction map was used to scale methane flux and isotope measurements. Our results suggest that the current values used in atmospheric inversion studies may oversimplify the relationship between plant and microbial communities in complex permafrost landscapes. As we gain a deeper understanding of how vegetation relates to methanogenic communities, understanding the spatial component of ecosystem methane metabolism and distribution will be increasingly valuable.

  9. Analysing land and vegetation cover dynamics during last three decades in Katerniaghat wildlife sanctuary, India

    Indian Academy of Sciences (India)

    V S Chitale; M D Behera

    2014-10-01

    The change in the tropical forests could be clearly linked to the expansion of the human population and economies. An understanding of the anthropogenic forcing plays an important role in analyzing the impacts of climate change and the fate of tropical forests in the present and future scenario. In the present study, we analyze the impact of natural and anthropogenic factors in forest dynamics in Katerniaghat wildlife sanctuary situated along the Indo-Nepal border in Uttar Pradesh state, India. The study site is under tremendous pressure due to anthropogenic factors from surrounding areas since last three decades. The vegetation cover of the sanctuary primarily comprised of Shorea robusta forests, Tectona grandis plantation, and mixed deciduous forest; while the land cover comprised of agriculture, barren land, and water bodies. The classification accuracy was 83.5%, 91.5%, and 95.2% with MSS, IKONOS, and Quickbird datasets, respectively. Shorea robusta forests showed an increase of 16 km2; while Tectona grandis increased by 63.01 km2 during 1975–2010. The spatial heterogeneity in these tropical vegetation classes surrounded by the human dominated agricultural lands could not be addressed using Landsat MSS data due to coarse spatial resolution; whereas the IKONOS and Quickbird satellite datasets proved to advantageous, thus being able to precisely address the variations within the vegetation classes as well as in the land cover classes and along the edge areas. Massive deforestation during 1970s along the adjoining international boundary with Nepal has led to destruction of the wildlife corridor and has exposed the wildlife sanctuary to interference like grazing and poaching. Higher rates of forest dynamics during the 25-year period indicate the vulnerability of the ecosystem to the natural and anthropogenic disturbances in the proximity of the sanctuary.

  10. Spatio - Temporal Variation of Aerosol and its relation to vegetation cover over mega-city New Delhi

    Science.gov (United States)

    Pandey, Alok; Pravesh Kumar, Ram; Berwal, Shivesh; Kumar, Krishan; Kumar, Ritesh

    2016-07-01

    MODerate resolution Imaging Spectro-radiometer (MODIS) on board NASA's Terra and Aqua satellite Level 2 Aerosol optical depth (AOD) data is used for aerosol study and LISS III sensor on board Indian Remote Sensing (IRS) Satellite procured from the National Remote Sensing Center (NRSC), Hyderabad, India was used for vegetation cover estimation over New Delhi and its surrounding regions. Lowest AOD was found in the spring and winter season where highest AOD in summer months. Different dates representing different seasons LISS III imageries were used for generation of land-cover maps for vegetation study. The land cover maps reveal that most of the surrounding areas of Delhi are covered with vegetation in the month of March. By the month of May-June herbs are cut or dry from most of the region surrounding Delhi and the land cover in the surrounding areas changes to bare soil. During the rainy season (July to September) the vegetation cover over Delhi and the surrounding areas increases significantly. In November - December there is dispersed vegetation cover over New Delhi and its surrounding regions depending upon the age of the newly sown crop and ornamental plants. We found that, there is statistically significant negative correlation between AOD and Vegetation in every season over New Delhi.

  11. Changes in Soil Spectral Reflectance Curves by Varying Percentages of Vegetative Cover

    Science.gov (United States)

    1981-02-27

    plant species used in this study were marigold (Targetes sp.) and silver lace dusty miller (Cineraria sp.), that were green (Munsell color 7.5GY4/4...collection, pots containing the marigolds were placed in a test plot in the 12 x 12 pot matrix to form the 100% vegetative cover condition. Soil was carefully...placed around each pot, so only sunlit and shadowed plants and soil formed the target in the field-of- view (FOV). The potted marigolds were removed

  12. Present-day vegetation helps quantifying past land cover in selected regions of the Czech Republic.

    Directory of Open Access Journals (Sweden)

    Vojtěch Abraham

    Full Text Available The REVEALS model is a tool for recalculating pollen data into vegetation abundances on a regional scale. We explored the general effect of selected parameters by performing simulations and ascertained the best model setting for the Czech Republic using the shallowest samples from 120 fossil sites and data on actual regional vegetation (60 km radius. Vegetation proportions of 17 taxa were obtained by combining the CORINE Land Cover map with forest inventories, agricultural statistics and habitat mapping data. Our simulation shows that changing the site radius for all taxa substantially affects REVEALS estimates of taxa with heavy or light pollen grains. Decreasing the site radius has a similar effect as increasing the wind speed parameter. However, adjusting the site radius to 1 m for local taxa only (even taxa with light pollen yields lower, more correct estimates despite their high pollen signal. Increasing the background radius does not affect the estimates significantly. Our comparison of estimates with actual vegetation in seven regions shows that the most accurate relative pollen productivity estimates (PPEs come from Central Europe and Southern Sweden. The initial simulation and pollen data yielded unrealistic estimates for Abies under the default setting of the wind speed parameter (3 m/s. We therefore propose the setting of 4 m/s, which corresponds to the spring average in most regions of the Czech Republic studied. Ad hoc adjustment of PPEs with this setting improves the match 3-4-fold. We consider these values (apart from four exceptions to be appropriate, because they are within the ranges of standard errors, so they are related to original PPEs. Setting a 1 m radius for local taxa (Alnus, Salix, Poaceae significantly improves the match between estimates and actual vegetation. However, further adjustments to PPEs exceed the ranges of original values, so their relevance is uncertain.

  13. Land Cover Classification in an Ecuadorian Mountain Geosystem Using a Random Forest Classifier, Spectral Vegetation Indices, and Ancillary Geographic Data

    Directory of Open Access Journals (Sweden)

    Johanna E. Ayala-Izurieta

    2017-05-01

    Full Text Available We presented a methodology to accurately classify mountainous regions in the tropics. These landscapes are complex in terms of their geology, ecosystems, climate and land use. Obtaining accurate maps to assess land cover change is essential. The objectives of this study were to (1 map vegetation using the Random Forest Classifier (RFC, spectral vegetation index (SVI, and ancillar geographic data (2 identify important variables that help differentiate vegetation cover, and (3 assess the accuracy of the vegetation cover classification in hard-to-reach Ecuadorian mountain region. We used Landsat 7 ETM+ satellite images of the entire scene, a RFC algorithm, and stratified random sampling. The altitude and the two band enhanced vegetation index (EVI2 provide more information on vegetation cover than the traditional and often use normalized difference vegetation index (NDVI in other settings. We classified the vegetation cover of mountainous areas within the 1016 km2 area of study, at 30 m spatial resolution, using RFC that yielded a land cover map with an overall accuracy of 95%. The user´s accuracy and the half-width of the confidence interval for 95% of the basic map units, forest (FOR, páramo (PAR, crop (CRO and pasture (PAS were 95.85% ± 2.86%, 97.64% ± 1.24%, 91.53% ± 3.35% and 82.82% ± 7.74%, respectively. The overall disagreement was 4.47%, which results from adding 0.43% of quantity disagreement and 4.04% of allocation disagreement. The methodological framework presented in this paper and the combined use of SVIs, ancillary geographic data, and the RFC allowed the accurate mapping of hard-to-reach mountain landscapes as well as uncovering the underlying factors that help differentiate vegetation cover in the Ecuadorian mountain geosystem.

  14. Assessing the Relationship Between Spectral Vegetation Indices and Shrub Cover in the Jornada Basin, New Mexico

    Science.gov (United States)

    Duncan, Jeff; Stow, D.; Franklin, J.; Hope, A.

    1993-01-01

    We assessed the statistical relations between Spectral Vegetation Indices (SVI's) derived from SPOT multi-spectral data and semi-arid shrub cover at the Jornada LTER site in New Mexico. Despite a limited range of shrub cover in the sample the analyses resulted in r(sup 2) values as high as 0 central dot 77. Greenness SVI's (e.g., Simple Ratio, NDVI, SAVI, PVI and an orthogonal Greenness index) were shown to be more sensitive to shrub type and phenology than brightness SVis (e.g., green, red and near-infrared reflectances and a Brightness index). The results varied substantially with small-scale changes in plot size (60m by 60m to 100m by 100m) as a consequence of landscape heterogeneity. The results also indicated the potential for the spectral differentiation of shrub types, and shrubs from grass, using multi-temporal, multi-spectral analysis.

  15. Effects of rainfall intensity and intermittency on woody vegetation cover and deep soil moisture in dryland ecosystems

    Science.gov (United States)

    Zhang, Ding-Hai; Li, Xin-Rong; Zhang, Feng; Zhang, Zhi-Shan; Chen, Yong-Le

    2016-12-01

    Identifying the relationship between the stochastic daily rainfall regime and the dynamics of plants and soil moisture is fundamental for the sustainable management of dryland ecosystems in a context of global climate change. An eco-hydrological model that couples the dynamics of woody vegetation cover and deep soil moisture (typically with a depth interval of 30-150 cm) was used to investigate the effect of stochastic intensity and the intermittency of precipitation on soil moisture in this deep interval, which affects woody vegetation cover. Our results suggest that the precipitation intensity and intermittency play an important role in the dynamics of wood vegetation cover and deep soil moisture. In arid and semiarid regions, as the annual precipitation increased, the rate of woody vegetation cover increased as a power-law function, and the deep soil moisture increased exponentially. For a given annual rainfall, there were positive correlations between the rainfall intensity (or rainfall intermittency) and both the woody vegetation cover and deep soil moisture. The positive correlations between wood vegetation cover and both rainfall intensity and intermittency may decrease with increases in the precipitation intensity or precipitation intermittency. The positive correlations between deep soil moisture and both rainfall intensity and rainfall intermittency increase as the precipitation intensity or precipitation intermittency increases. Moreover, these positive correlations may increase with increases in the mean annual rainfall. Our results emphasize the importance of daily precipitation variations in controlling the responses of woody vegetation cover and deep soil moisture to climate variations in arid and semiarid regions. Our model can aid the understanding of rainfall processes and indicates that increases in rainfall intensity or rainfall intermittency may lead to an increase in woody vegetation cover and deep soil moisture given an invariable annual

  16. Urban environmental stewardship and changes in vegetative cover and building footprint in New York City neighborhoods (2000-2010)

    Science.gov (United States)

    Dexter H. Locke; Kristen L. King; Erika S. Svendsen; Lindsay K. Campbell; Christopher Small; Nancy F. Sonti; Dana R. Fisher; Jacqueline W.T. Lu

    2014-01-01

    This study explores the connections between vegetation cover change, environmental stewardship, and building footprint change in New York City neighborhoods from the years 2000 to 2010. We use a mixed-methods multidisciplinary approach to analyze spatially explicit social and ecological data. Most neighborhoods lost vegetation during the study period. Neighborhoods...

  17. Simulating the effect of vegetation cover on the sediment yield of mediterranean catchments using SHETRAN

    Science.gov (United States)

    Lukey, B. T.; Sheffield, J.; Bathurst, J. C.; Lavabre, J.; Mathys, N.; Martin, C.

    1995-08-01

    The sediment yield of two catchments in southern France was modelled using the newly developed sediment code of SHETRAN. A fire in August 1990 denuded the Rimbaud catchment, providing an opportunity to study the effect of vegetation cover on sediment yield by running the model for both pre-and post-fire cases. Model output is in the form of upper and lower bounds on sediment discharge, reflecting the uncertainty in the erodibility of the soil. The results are encouraging since measured sediment discharge falls largely between the predicted bounds, and simulated sediment yield is dramatically lower for the catchment before the fire which matches observation. SHETRAN is also applied to the Laval catchment, which is subject to Badlands gulley erosion. Again using the principle of generating upper and lower bounds on sediment discharge, the model is shown to be capable of predicting the bulk sediment discharge over periods of months. To simulate the effect of reforestation, the model is run with vegetation cover equivalent to a neighbouring fully forested basin. The results obtained indicate that SHETRAN provides a powerful tool for predicting the impact of environmental change and land management on sediment yield.

  18. Landslides and vegetation cover in the 2005 North Pakistan earthquake: a GIS and statistical quantitative approach

    Science.gov (United States)

    Peduzzi, P.

    2010-04-01

    The growing concern for loss of services once provided by natural ecosystems is getting increasing attention. However, the accelerating rate of natural resources destruction calls for rapid and global action. With often very limited budgets, environmental agencies and NGOs need cost-efficient ways to quickly convince decision-makers that sound management of natural resources can help to protect human lives and their welfare. The methodology described in this paper, is based on geospatial and statistical analysis, involving simple Geographical Information System (GIS) and remote sensing algorithms. It is based on free or very low-cost data. It aims to scientifically assess the potential role of vegetation in mitigating landslides triggered by earthquakes by normalising for other factors such as slopes and distance from active fault. The methodology was applied to the 2005 North Pakistan/India earthquake which generated a large number of victims and hundreds of landslides. The study shows that if slopes and proximity from active fault are the main susceptibility factors for post landslides triggered by earthquakes in this area, the results clearly revealed that areas covered by denser vegetation suffered less and smaller landslides than areas with thinner (or devoid of) vegetation cover. Short distance from roads/trails and rivers also proved to be pertinent factors in increasing landslides susceptibility. This project is a component of a wider initiative involving the Global Resource Information Database Europe from the United Nations Environment Programme, the International Union for Conservation of Nature, the Institute of Geomatics and Risk Analysis from the University of Lausanne and the "institut universitaire d'études du développement" from the University of Geneva.

  19. Landslides and vegetation cover in the 2005 North Pakistan earthquake: a GIS and statistical quantitative approach

    Directory of Open Access Journals (Sweden)

    P. Peduzzi

    2010-04-01

    Full Text Available The growing concern for loss of services once provided by natural ecosystems is getting increasing attention. However, the accelerating rate of natural resources destruction calls for rapid and global action. With often very limited budgets, environmental agencies and NGOs need cost-efficient ways to quickly convince decision-makers that sound management of natural resources can help to protect human lives and their welfare. The methodology described in this paper, is based on geospatial and statistical analysis, involving simple Geographical Information System (GIS and remote sensing algorithms. It is based on free or very low-cost data. It aims to scientifically assess the potential role of vegetation in mitigating landslides triggered by earthquakes by normalising for other factors such as slopes and distance from active fault. The methodology was applied to the 2005 North Pakistan/India earthquake which generated a large number of victims and hundreds of landslides. The study shows that if slopes and proximity from active fault are the main susceptibility factors for post landslides triggered by earthquakes in this area, the results clearly revealed that areas covered by denser vegetation suffered less and smaller landslides than areas with thinner (or devoid of vegetation cover. Short distance from roads/trails and rivers also proved to be pertinent factors in increasing landslides susceptibility. This project is a component of a wider initiative involving the Global Resource Information Database Europe from the United Nations Environment Programme, the International Union for Conservation of Nature, the Institute of Geomatics and Risk Analysis from the University of Lausanne and the "institut universitaire d'études du développement" from the University of Geneva.

  20. Application of Industrial Waste CaF2 for Vegetative Covering of Phosphogypsum Disposal Site

    Directory of Open Access Journals (Sweden)

    Leaković, S.

    2012-11-01

    Full Text Available Phosphogypsum, i.e. calcium sulphate dihydrate is generated as a by-product in the phosphoric acid production during reaction between phosphate rock and sulphuric acid. It is stored as nonhazardous waste in a disposal site. Since 1983, when the phosphoric acid plant started operation, about 8 140 000 t of phosphogypsum have been disposed there. The disposal site consists of four separate ponds (compartments which are bounded by 6 meter high embankments of earth. According to a special design, it is possible to build layers upon the existing disposal site using phosphogypsum for making embankments. So far, the first 6-meter high level has been built with a 1:3 side slope of phosphogypsum embankments. Formation of the second level with 1:5 side slope is currently in progress. Another byproduct of phosphoric acid production is fluoride- and phosphorus-polluted wastewater. Before being discharged into the natural recipient, this wastewater is treated with calcium hydroxide. The product of neutralisation is calcium fluoride (CaF2 which is deposited in separate lagoons as nonhazardous waste. The application of calcium fluoride as a substrate for plants in the process of vegetative covering of the phosphogypsum disposal site is a new method of its usage. This way, a significant financial benefit is achieved because it is not necessary to build a new lagoon for calcium fluoride disposal. Regarding the environmental aspect, usage for vegetative covering is far better than the standard process of calcium fluoride disposal because residual phosphorus from CaF2 is utilised for enhanced growth of the plants. At the same time, the necessity for natural soil covering of the disposal site is reduced by 500 000 m3. Apart from the natural grass species, alfalfa (Medicago sativa L., Bermuda grass (Cynodon dactylon (L. Pers., grass mixtures with high content of red fescue (Festuca rubra L. and false indigo bush (Amorpha fruticosa L. displayed the best growth on the

  1. NDVI indicated characteristics of vegetation cover change in China's metropolises over the last three decades.

    Science.gov (United States)

    Sun, Jinyu; Wang, Xuhui; Chen, Anping; Ma, Yuecun; Cui, Mengdi; Piao, Shilong

    2011-08-01

    How urban vegetation was influenced by three decades of intensive urbanization in China is of great interest but rarely studied. In this paper, we used satellite derived Normalized Difference Vegetation Index (NDVI) and socioeconomic data to evaluate effects of urbanization on vegetation cover in China's 117 metropolises over the last three decades. Our results suggest that current urbanization has caused deterioration of urban vegetation across most cities in China, particularly in East China. At the national scale, average urban area NDVI (NDVI(u)) significantly decreased during the last three decades (P < 0.01), and two distinct periods with different trends can be identified, 1982-1990 and 1990-2006. NDVI(u) did not show statistically significant trend before 1990 but decrease remarkably after 1990 (P < 0.01). Different regions also showed difference in the timing of NDVI(u) turning point. The year when NDVI(u) started to decline significantly for Central China and East China was 1987 and 1990, respectively, while NDVI(u) in West China remained relatively constant until 1998. NDVI(u) changes in the Yangtze River Delta and the Pearl River Delta, two regions which has been undergoing the most rapid urbanization in China, also show different characteristics. The Pearl River Delta experienced a rapid decline in NDVI(u) from the early 1980s to the mid-1990s; while in the Yangtze River Delta, NDVI(u) did not decline significantly until the early 1990s. Such different patterns of NDVI(u) changes are closely linked with policy-oriented difference in urbanization dynamics of these regions, which highlights the importance of implementing a sustainable urban development policy.

  2. Permafrost Thaw and Vegetation Cover Change May Alter Silicon Exports to Arctic Coastal Receiving Waters

    Science.gov (United States)

    Spencer, R.; Carey, J.; Tang, J.

    2016-12-01

    Silicon (Si) availability in Arctic coastal waters is a critical factor dictating phytoplankton species composition, as diatoms require as much Si as nitrogen (N) on a molar basis to survive. Riverine exports are the main source of Si to Arctic coastal waters annually and thus, the timing and magnitude of river Si fluxes have direct implications for marine ecology and global carbon dynamics. Although geochemical factors exert large controls on Si exports to marine waters, watershed land cover has recently been shown to alter the retention and transport of Si along the land-ocean continuum in lower latitudes, due in large part to the ability of terrestrial vegetation to store large quantities of Si in its tissue. However, it is unclear how shifts in basin land cover and climatic warming will alter Si exports in the Arctic, as increasing shrubiness and northward migration of treeline may increase Si retention on land, but permafrost thaw and elevated weathering rates may stimulate Si exports towards coastal waters. In this study we investigate how permafrost thaw and vegetation cover shifts are altering Arctic riverine Si export using the geochemical signatures of ten rivers draining a 700 km north-south gradient across the Yukon and Arctic North Slope basins in Alaska. Across the 2016 spring freshet, average dissolved Si (DSi) concentrations across sites ranged from 22 to 115 µM, with a significant negative relationship observed between average DSi concentration and latitude (r=-0.95, ptotal suspended solids (TSS), and Ge (Germanium)/Si ratios, to determine the drivers of these patterns in Si behavior. In turn, our results will be used to create the first predictive framework to assess how future warming will alter fluvial Si exports to Arctic receiving waters.

  3. 植被覆盖度遥感估算研究进展%A Review on Fractional Vegetation Cover Estimation Using Remote Sensing

    Institute of Scientific and Technical Information of China (English)

    贾坤; 姚云军; 魏香琴; 高帅; 江波; 赵祥

    2013-01-01

    unmixing model is extensively used for its simple form and certain physical significance,and the neural network method is widely used for generating products because of its extendibility and rapidity of calculation.Furthermore,the existing remote sensing data based fractional vegetation cover products are presented.However,the validation results indicate that almost all of the fractional vegetation cover products have underestimation problem and variational estimation accuracy in different regions.Finally,the fractional vegetation cover estimation research prospect is discussed and high spatial-temporal resolution global fractional vegetation cover dataset,multi-source remote sensing data fusion and assimilation method are the future development of fractional vegetation cover estimation using remote sensing data.

  4. Urban vegetation cover extraction from hyperspectral imagery and geographic information system spatial analysis techniques: case of Athens, Greece

    Science.gov (United States)

    Petropoulos, George P.; Kalivas, Dionissios P.; Georgopoulou, Iro A.; Srivastava, Prashant K.

    2015-01-01

    The present study aimed at evaluating the performance of two different pixel-based classifiers [spectral angle mapper (SAM) and support vector machines (SVMs)] in discriminating different land-cover classes in a typical urban setting, focusing particularly on urban vegetation cover by utilizing hyperspectral (EO-1 Hyperion) data. As a case study, the city of Athens, Greece, was used. Validation of urban vegetation predictions was based on the error matrix statistics. Additionally, the final urban vegetation cover maps were compared at a municipality level against reference urban vegetation cover estimates derived from the digitization of very high-resolution imagery. To ensure consistency and comparability of the results, the same training and validation points dataset were used to compare the different classifiers. The results showed that SVMs outperformed SAM in terms of both classification and urban vegetation cover mapping with an overall accuracy of 86.53% and Kappa coefficient 0.823, whereas for SAM classification, the accuracy statistics obtained were 75.13% and 0.673, respectively. Our results confirmed the ability of both techniques, when combined with Hyperion imagery, to extract urban vegetation cover for the case of a densely populated city with complex urban features, such as Athens. Our findings offer significant information at the local scale as regards to the presence of open green spaces in the urban environment of Athens. Such information is vital for successful infrastructure development, urban landscape planning, and improvement of urban environment. More widely, this study also contributes significantly toward an objective assessment of Hyperion in detecting and mapping urban vegetation cover.

  5. [Retrieval of Copper Pollution Information from Hyperspectral Satellite Data in a Vegetation Cover Mining Area].

    Science.gov (United States)

    Qu, Yong-hua; Jiao, Si-hong; Liu, Su-hong; Zhu, Ye-qing

    2015-11-01

    level, using stepwise multiple linear regression and cross validation on the dataset which is consisting of 44 groups of copper ion content information in the polluted vegetation leaves from Dexing Copper Mine in Jiangxi Province to build up a statistical model by also incorporating the HJ-1 satellite images. This model was then used to estimate the copper content distribution over the whole research area at Dexing Copper Mine. The result has shown that there is strong statistical significance of the model which revealed the most sensitive waveband to copper ion is located at 516 nm. The distribution map illustrated that the copper ion content is generally in the range of 0-130 mg · kg⁻¹ in the vegetation covering area at Dexing Copper Mine and the most seriously polluted area is located at the South-east corner of Dexing City as well as the mining spots with a higher value between 80 and 100 mg · kg⁻¹. This result is consistent with the ground observation experiment data. The distribution map can certainly provide some important basic data on the copper pollution monitoring and treatment.

  6. 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....

  7. Changes in vegetation structure in seeded nesting cover in the prairie pothole region

    Science.gov (United States)

    Higgins, K.F.; Barker, W.T.

    1982-01-01

    A sample of 365 stands of seeded nesting cover (mixtures of cool-season grasses and legumes) was studied in the glaciated prairie pothole region during 1977-79. Measurements of species composition, canopy cover, plant height, and visual obstruction values differed with stand age but only in a general way when results from over the entire region were pooled. Maximum values for plant height and visual obstruction occurred once per stand during the first 10 growing seasons. Although the year of maximum growth was variable and unpredictable, stands showed trends of degeneration in height and visual obstruction after the year of maximum growth.Seeded nesting cover grew similarly throughout the region when on soils of capability class IV or better and within a precipitation range of 30 to 61 cm. Precipitation was the factor that most affected stand growth, especially the amount received in the year before spring measurements. Height and visual obstruction values within a stand were also directly affected by some individual species and by the percentage of grass within a stand. In 2 of the 3 study years, the height and visual obstruction values of residual cover were extremely reduced by ice pack, heavy snow pack, or a combination of snow pack and harvest by rodents. Such events, if frequent, largely negate the possibility of using minimum visual obstruction or plant height measurements for assessing quality of vegetation for wildlife cover and management purposes.Species composition, number of species, and canopy cover varied most during the first three growing seasons and least during the next six. Succession toward dominance by native grasses and forbs and woody species was retarded by the predominance of the species of seeded nesting cover, at least during the first 10 growing seasons.All stands had at least one species present that was either a noxious weed, a problem cropland weed, or a nuisance weed. Weeds were usually local in distribution. Five weed species

  8. Using high-resolution radar images to determine vegetation cover for soil erosion assessments.

    Science.gov (United States)

    Bargiel, D; Herrmann, S; Jadczyszyn, J

    2013-07-30

    Healthy soils are crucial for human well-being. Because soils are threatened worldwide, politicians recognize the need for soil protection. For example, the European Commission has launched the Thematic Strategy for Soil Protection, which requests the European member states to identify high risk areas for soil degradation. Most states use the Universal Soil Loss Equation (USLE) to assess soil erosion risk at the national scale. The USLE includes different factors, one of them is the vegetation cover and management factor (C factor). Modern satellite-based radar sensors now provide highly accurate vegetation cover data, enabling opportunities to improve the accuracy of the C factor. The presented study proves the suitability for C factor determination based on a multi-temporal classification of high-resolution radar images. Further USLE factors were derived from existing data sources (meteorological data, soil maps, digital elevation model) to conduct an USLE-based soil erosion assessment. The resulting map illustrates a qualitative assessment for soil erosion risk within a plot of about 7*12 km in an agricultural region in Poland that is very susceptible to soil erosion processes. A high erosion risk of more than 10 tonnes per ha and year was assessed to occur on 13.6% (646 ha) of the agricultural areas within the investigated plot. Further 7.8% (372 ha) of agricultural land is threaten by a medium risk of 5-10 tonnes per ha and year. Such a spatial information about areas of high or medium soil erosion risk are crucial for the development of strategies for the protection of soils.

  9. Use of LANDSAT images of vegetation cover to estimate effective hydraulic properties of soils

    Science.gov (United States)

    Eagleson, Peter S.; Jasinski, Michael F.

    1988-01-01

    The estimation of the spatially variable surface moisture and heat fluxes of natural, semivegetated landscapes is difficult due to the highly random nature of the vegetation (e.g., plant species, density, and stress) and the soil (e.g., moisture content, and soil hydraulic conductivity). The solution to that problem lies, in part, in the use of satellite remotely sensed data, and in the preparation of those data in terms of the physical properties of the plant and soil. The work was focused on the development and testing of a stochastic geometric canopy-soil reflectance model, which can be applied to the physically-based interpretation of LANDSAT images. The model conceptualizes the landscape as a stochastic surface with bulk plant and soil reflective properties. The model is particularly suited for regional scale investigations where the quantification of the bulk landscape properties, such as fractional vegetation cover, is important on a pixel by pixel basis. A summary of the theoretical analysis and the preliminary testing of the model with actual aerial radiometric data is provided.

  10. Evaluation of two methods for measuring saturated hydraulic conductivity of soils under two vegetation covers

    Energy Technology Data Exchange (ETDEWEB)

    Rubio, C.M.; Josa, R.; Poyatos, R.; Llorens, P.; Gallart, F.; Latron, J.; Ferrer, F.

    2009-07-01

    The main goal of this work is to determine and to evaluate the saturated hydraulic conductivity for a silt loam soil in field and laboratory conditions. the experimental area was located in the Vallcebre research catchment, in headwaters of the Llobregat River (NE Spain). Hydraulic conductivity was measured in the field using the Guelph permeameter and field saturated hydraulic conductivity (K{sub f}s) based on Elrick equation was calculated. The Guelph permeameter measures were made in two conditions (dry and wet) and in profiles below two vegetation covers (meadows and forest). To determine the saturated hydraulic conductivity at the laboratory (K{sub s}) the constant head permeameter was used. The average K{sub f}s values for the wet period was about 2 cm.h{sup -}1. During the dry period, both soil profiles presented higher values, about 7.5 cm.h{sup -}1. Under laboratory conditions, means observed K{sub s} values were between 12 and 25 cm.h{sup -}1. The relationship K{sub f}s/k{sub s} was of 0.1 cm.h{sup -}1 in wet conditions and about 0.4 cm.h{sup -}1 in dry conditions. The results indicated significant differences between both methods and between both seasons. differences can be explained by the anisotropy of soils as a consequence of vegetation root system that promotes preferential flows paths. (Author) 10 refs.

  11. Invertebrate availability and vegetation characteristics explain use of nonnesting cover types by mature-forest songbirds during the postfledging period

    Science.gov (United States)

    Streby, Henry M.; Peterson, Sean M.; Andersen, D.E.

    2011-01-01

    Some species of mature-forest-nesting songbirds use regenerating clearcuts and forested wetlands during the postfledging period (between nesting and migration). Relatively dense vegetation structure and abundant food resources in non-mature-forest cover types have been hypothesized to explain this phenomenon. We examined the relative importance of vegetation structure and invertebrate availability on use of nonnesting cover types by adult and hatch-year Ovenbirds (Seiurus aurocapilla) and American Redstarts (Setophaga ruticilla) during the postfledging period of 2009 in northern Minnesota. We used mist nets to sample bird use of forested wetlands and regenerating clearcuts of three age groups: 1-6, 7-12, and 16-19 yr after harvest. We modeled captures of birds using vegetation characteristics and invertebrate availability sampled around nets as explanatory variables. For all birds studied, captures were best explained by food availability and secondarily by vegetation characteristics including litter depth and woody debris for Ovenbirds and canopy height for American Redstarts. Shrub-level invertebrate availability received a cumulative weight of 0.74-0.99 in Akaike's information criterion corrected ranked models for adult and hatch-year birds of both species. Vegetation density and variation in vegetation density explained almost no variation in captures of either species. We conclude that both invertebrate availability and some vegetation characteristics influence use of nonnesting cover types by Ovenbirds and American Redstarts during the postfledging period, but that invertebrate availability is generally the stronger predictor of that use. ?? 2011 Association of Field Ornithologists.

  12. Synchronous estimation of DTM and fractional vegetation cover in forested area from airborne LIDAR height and intensity data

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    We proposed a method to separate ground points and vegetation points from discrete return,small footprint airborne laser scanner data,called skewness change algorithm.The method,which makes use of intensity of laser scanner data,is especially applicable in steep,and forested areas.It does not take slope of forested area into account,while other algorithms consider the change of slope in steep forested area.The ground points and vegetation points can be used to estimate digital terrain model(DTM) and fractional vegetation cover,respectively.A few vegetation points which were classified into the ground points were removed as noise before the generation of DTM.This method was tested in a test area of 10000 square meters.A LiteMapper -5600 laser system was used and a flight was carried out over a ground of 700―800 m.In this tested area,a total number of 1546 field measurement ground points were measured with a total station TOPCON GTS-602 and TOPCON GTS -7002 for validation of DTM and the mean error value is -18.5 cm and the RMSE(root mean square error) is ±20.9 cm.A data trap sizes of 4m in diameter from airborne laser scanner data was selected to compute vegetation fraction cover.Validation of fractional vegetation cover was carried out using 15 hemispherical photographs,which are georeferenced to centimeter accuracy by differential GPS.The gap fraction was computed over a range of zenith angles 10° using the gap light analyzer(GLA) from each hemispherical photograph.The R2 for the regression of fractional vegetation cover from these ALS data and the respective field measurements is 0.7554.So this study presents a method for synchronous estimation of DTM and fractional vegetation cover in forested area from airborne LIDAR height and intensity data.

  13. Coberturas vegetais no desenvolvimento vegetativo de plantas de pessegueiro Crop covers in the vegetative development of peach trees

    Directory of Open Access Journals (Sweden)

    Leo Rufato

    2007-04-01

    Full Text Available A utilização de cultivos de cobertura em pomares de pessegueiro no Brasil ainda é pouco difundida, apesar de haver diversas espécies de cobertura vegetal com potencial para tanto. Neste trabalho, estudaram-se os efeitos da a utilização de cinco espécies de plantas para cobertura vegetal de inverno: aveia-preta, chícharo, ervilha forrageira; nabo forrageiro; tremoço-azul, quatro consorciações entre elas e mais a testemunha, com vegetação espontânea sobre o desenvolvimento vegetativo de plantas de pessegueiro cv. Maciel sobre capedeboscq. Todas as espécies vegetais avaliadas adaptaram-se como cobertura vegetal nas condições edafoclimáticas da região Sul do Rio Grande do Sul. As coberturas vegetais, com exceção, sobretudo, do nabo forrageiro, incrementaram o desenvolvimento das plantas de pessegueiro.The use of the crop covers in Brazilian peach orchards is still not so spread, though there are several species of crop covers with the potential have the effect studied. This research presents the effects of the five plant species use for winter vegetal crop covers: Avena strigosa, Lathyrus sativus, Pisum sativum subesp. arvense, Raphanus sativus var. oleiferus, Lupinus angustifolius, four combinations among these species and the control treatments (native vegetation, with spontaneous vegetationon the vegetative development of "Maciel" peach tree under Capdeboscq rootstock. All of the crop covers evaluated adapted themselves to the soil and climate conditions of the south of "Rio Grande do Sul'. The crop covers, except the Raphanus sativus var. oleiferus, increased positively the phenological and vegetative development of peach trees; the Lupinus angustifolius also increased the phenological and vegetative development of plants.

  14. [Quantitative estimation of vegetation cover and management factor in USLE and RUSLE models by using remote sensing data: a review].

    Science.gov (United States)

    Wu, Chang-Guang; Li, Sheng; Ren, Hua-Dong; Yao, Xiao-Hua; Huang, Zi-Jie

    2012-06-01

    Soil loss prediction models such as universal soil loss equation (USLE) and its revised universal soil loss equation (RUSLE) are the useful tools for risk assessment of soil erosion and planning of soil conservation at regional scale. To make a rational estimation of vegetation cover and management factor, the most important parameters in USLE or RUSLE, is particularly important for the accurate prediction of soil erosion. The traditional estimation based on field survey and measurement is time-consuming, laborious, and costly, and cannot rapidly extract the vegetation cover and management factor at macro-scale. In recent years, the development of remote sensing technology has provided both data and methods for the estimation of vegetation cover and management factor over broad geographic areas. This paper summarized the research findings on the quantitative estimation of vegetation cover and management factor by using remote sensing data, and analyzed the advantages and the disadvantages of various methods, aimed to provide reference for the further research and quantitative estimation of vegetation cover and management factor at large scale.

  15. Variations in vegetation cover and topography control gully density and sediment production on the Chinese Loess Plateau

    Science.gov (United States)

    Zhao, Jianlin; Govers, Gerard

    2016-04-01

    The factors controlling topsoil erosion rates are relatively well understood. This explains why topsoil erosion rates on the Chinese loess plateau (CLP) can be relatively accurately estimated using a combination of empirical data and relatively simple models (Zhao et al., in press). This is, however, not the case for non-topsoil erosion (sediment production by gullying and landslides): while it is well known that these processes produce significant amounts of sediment, the factors controlling their intensity on the CLP are far less understood. In this study, the contribution of non-topsoil erosion to total sediment production on the CLP was investigated. We estimated non-topsoil erosion rates (ENT) by making the difference between measured total sediment yield and the estimated topsoil erosion in 46 gauged catchments on the CLP for the period 1950-1970, when soil conservation measures were mostly absent in the area. We tested an extensive set of environmental variables related to topography, climate and the impact of land use for correlation Our results showed that the average catchment erosion rate (E) and ENT between 1950 and 1970 were 68.29 tha-1yr-1 and 58.02 tha-1yr-1 respectively. The sediment contribution of non-topsoil erosion to total sediment production ranged between 0 and 97% with a mean of 70%. Both E and ENT were significantly related with river slope, land use, NDVI, and gully density. However, gully density was the only variable explaining a major part of the variance in both E (60%) and ENT (57%). Gully density itself was significantly related to topography and vegetation cover but not to precipitation. Importantly, gully density was not only related to overall slope steepness, but also the river gradients and the hypsometric integral, suggesting that not only land cover disturbance but also tectonic uplift may control gully density and erosion rates. The absence of a clear climate signal, both with respect to the variation in gully density and in

  16. Spatial Variation of Temperature and Precipitation in Bhutan and Links to Vegetation and Land Cover

    Directory of Open Access Journals (Sweden)

    Ugyen Dorji

    2016-02-01

    Full Text Available Bhutan, located in the Himalayas in the South Asian monsoon region, has extremely high variation in elevation, climatic conditions, and land cover despite its small geographical area, as well as great biodiversity. This paper provides the first comprehensive description of climatic conditions in Bhutan. It assesses the spatial variation of temperature and precipitation across the country and evaluates the causes for this variation based on daily data from 70 meteorological stations that have been recording data for time spans ranging from 3 to 21 years. Temperature and precipitation show contrasting spatial variation, with temperature primarily affected by elevation and precipitation by latitude. Models were developed using mixed linear regression models to predict seasonal and annual mean temperature and precipitation based on geographical location. Using linear regression we found that temperatures changed by about 0.5°C for every 100 m of change in elevation, with lapse rates being highest in February, March, and November and lowest from June to August. The lapse rate was highest for minimum temperatures and lowest for maximum temperatures, with the greatest difference during winter. The spatial distribution of precipitation was mainly controlled by latitude, having a quadratic relationship, with the highest rates in the southern foothills of the Himalayan range and the lowest at midlatitudes. The land cover is affected by topography and local climate, with variations in temperature being a main deciding factor for vegetation types; most human settlements and associated land uses are concentrated at lower elevations.

  17. Remote sensing of vegetation and land-cover change in Arctic Tundra Ecosystems

    Science.gov (United States)

    Stow, D.A.; Hope, A.; McGuire, D.; Verbyla, D.; Gamon, J.; Huemmrich, F.; Houston, S.; Racine, C.; Sturm, M.; Tape, K.; Hinzman, L.; Yoshikawa, K.; Tweedie, C.; Noyle, B.; Silapaswan, C.; Douglas, D.; Griffith, B.; Jia, G.; Epstein, H.; Walker, D.; Daeschner, S.; Petersen, A.; Zhou, L.; Myneni, R.

    2004-01-01

    The objective of this paper is to review research conducted over the past decade on the application of multi-temporal remote sensing for monitoring changes of Arctic tundra lands. Emphasis is placed on results from the National Science Foundation Land-Air-Ice Interactions (LAII) program and on optical remote sensing techniques. Case studies demonstrate that ground-level sensors on stationary or moving track platforms and wide-swath imaging sensors on polar orbiting satellites are particularly useful for capturing optical remote sensing data at sufficient frequency to study tundra vegetation dynamics and changes for the cloud prone Arctic. Less frequent imaging with high spatial resolution instruments on aircraft and lower orbiting satellites enable more detailed analyses of land cover change and calibration/validation of coarser resolution observations. The strongest signals of ecosystem change detected thus far appear to correspond to expansion of tundra shrubs and changes in the amount and extent of thaw lakes and ponds. Changes in shrub cover and extent have been documented by modern repeat imaging that matches archived historical aerial photography. NOAA Advanced Very High Resolution Radiometer (AVHRR) time series provide a 20-year record for determining changes in greenness that relates to photosynthetic activity, net primary production, and growing season length. The strong contrast between land materials and surface waters enables changes in lake and pond extent to be readily measured and monitored. ?? 2003 Elsevier Inc. All rights reserved.

  18. Vegetation cover analysis using a low budget hyperspectral proximal sensing system

    Directory of Open Access Journals (Sweden)

    C. Daquino

    2006-06-01

    Full Text Available This report describes the implementation of a hyperspectral proximal sensing low-budget acquisition system and its application to the detection of terrestrian vegetation cover anomalies in sites of high environmental quality. Anomalies can be due to stress for lack of water and/or pollution phenomena and weed presence in agricultural fields. The hyperspectral cube (90-bands ranging from 450 to 900 nm was acquired from the hill near Segni (RM, approximately 500 m far from the target, by means of electronically tunable filters and 8 bit CCD cameras. Spectral libraries were built using both endmember identification method and extraction of centroids of the clusters obtained from a k-means analysis of the image itself. Two classification methods were applied on the hyperspectral cube: Spectral Angle Mapper (hard and Mixed Tuned Matching Filters (MTMF. Results show the good capability of the system in detecting areas with an arboreal, shrub or leafage cover, distinguishing between zones with different spectral response. Better results were obtained using spectral library originated by the k-means method. The detected anomalies not correlated to seasonal phenomena suggest a ground true analysis to identify their origin.

  19. Changes in the Vegetation Cover in a Constructed Wetland at Argonne National Laboratory, Illinois

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, C.L.; LaGory, K.

    2004-01-01

    Wetlands are valuable resources that are disappearing at an alarming rate. Land development has resulted in the destruction of wetlands for approximately 200 years. To combat this destruction, the federal government passed legislation that requires no net loss of wetlands. The United States Army Corps of Engineers (USACE) is responsible for regulating wetland disturbances. In 1991, the USACE determined that the construction of the Advanced Photon Source at Argonne National Laboratory would damage three wetlands that had a total area of one acre. Argonne was required to create a wetland of equal acreage to replace the damaged wetlands. For the first five years after this wetland was created (1992-1996), the frequency of plant species, relative cover, and water depth was closely monitored. The wetland was not monitored again until 2002. In 2003, the vegetation cover data were again collected with a similar methodology to previous years. The plant species were sampled using quadrats at randomly selected locations along transects throughout the wetland. The fifty sampling locations were monitored once in June and percent cover of each of the plant species was determined for each plot. Furthermore, the extent of standing water in the wetland was measured. In 2003, 21 species of plants were found and identified. Eleven species dominated the wetland, among which were reed canary grass (Phalaris arundinacea), crown vetch (Coronilla varia), and Canada thistle (Cirsium arvense). These species are all non-native, invasive species. In the previous year, 30 species were found in the same wetland. The common species varied from the 2002 study but still had these non-native species in common. Reed canary grass and Canada thistle both increased by more than 100% from 2002. Unfortunately, the non-native species may be contributing to the loss of biodiversity in the wetland. In the future, control measures should be taken to ensure the establishment of more desired native species.

  20. Climate-driven changes in grassland vegetation, snow cover, and lake water of the Qinghai Lake basin

    Science.gov (United States)

    Wang, Xuelu; Liang, Tiangang; Xie, Hongjie; Huang, Xiaodong; Lin, Huilong

    2016-07-01

    Qinghai Lake basin and the lake have undergone significant changes in recent decades. We examine MODIS-derived grassland vegetation and snow cover of the Qinghai Lake basin and their relations with climate parameters during 2001 to 2010. Results show: (1) temperature and precipitation of the Qinghai Lake basin increased while evaporation decreased; (2) most of the grassland areas improved due to increased temperature and growing season precipitation; (3) weak relations between snow cover and precipitation/vegetation; (4) a significantly negative correlation between lake area and temperature (r=-0.9, presponsible for the degradation of vegetation cover in Namco Lake basin. These results suggest different responses to the similar warming climate: improved (degraded) ecological condition and productive capacity of the Qinghai Lake basin (Namco Lake basin).

  1. Unravelling long-term vegetation change patterns in a binational watershed using multitemporal land cover data and historical photography

    Science.gov (United States)

    Villarreal, M.L.; Norman, L.M.; Webb, R.H.; Boyer, D.E.; Turner, R.M.

    2011-01-01

    A significant amount of research conducted in the Sonoran Desert of North America has documented, both anecdotally and empirically, major vegetation changes over the past century due to human land use activities. However, many studies lack coincidental landscape-scale data characterizing the spatial and temporal manifestation of these changes. Vegetation changes in a binational (USA and Mexico) watershed were documented using a series of four land cover maps (1979-2009) derived from multispectral satellite imagery. Cover changes are compared to georeferenced, repeat oblique photographs dating from the late 19th century to present. Results indicate the expansion of grassland over the past 20 years following nearly a century of decline. Historical repeat photography documents early-mid 20th century mesquite invasions, but recent land cover data and rephotography demonstrate declines in xeroriparian/riparian mesquite communities in recent decades. These vegetation changes are variable over the landscape and influenced by topography and land management. ?? 2011 IEEE.

  2. Regional adaptation of a dynamic global vegetation model using a remote sensing data derived land cover map of Russia

    Science.gov (United States)

    Khvostikov, S.; Venevsky, S.; Bartalev, S.

    2015-12-01

    The dynamic global vegetation model (DGVM) SEVER has been regionally adapted using a remote sensing data-derived land cover map in order to improve the reconstruction conformity of the distribution of vegetation functional types over Russia. The SEVER model was modified to address noticeable divergences between modelling results and the land cover map. The model modification included a light competition method elaboration and the introduction of a tundra class into the model. The rigorous optimisation of key model parameters was performed using a two-step procedure. First, an approximate global optimum was found using the efficient global optimisation (EGO) algorithm, and afterwards a local search in the vicinity of the approximate optimum was performed using the quasi-Newton algorithm BFGS. The regionally adapted model shows a significant improvement of the vegetation distribution reconstruction over Russia with better matching with the satellite-derived land cover map, which was confirmed by both a visual comparison and a formal conformity criterion.

  3. Impacts of grassland types and vegetation cover changes on surface air temperature in the regions of temperate grassland of China

    Science.gov (United States)

    Shen, Xiangjin; Liu, Binhui; Li, Guangdi; Yu, Pujia; Zhou, Daowei

    2016-10-01

    The sensitivity of surface air temperature response to different grassland types and vegetation cover changes in the regions of temperate grassland of China was analyzed by observation minus reanalysis (OMR) method. The basis of the OMR approach is that reanalysis data are insensitive to local surface properties, so the temperature differences between surface observations and reanalysis can be attributed to land effects. Results showed that growing-season air temperature increased by 0.592 °C/decade in the regions of temperate grassland of China, with about 31 % of observed warming associated with the effects of grassland types and vegetation cover changes. For different grassland types, the growing-season OMR trend was the strongest for temperate desert steppe (0.259 °C/decade) and the weakest for temperate meadow (0.114 °C/decade). Our results suggest that the stronger intraseasonal changes of grassland vegetation are present, the more sensitive the OMR trend responds to the intraseasonal vegetation cover changes. In August and September, the OMR of temperate meadow showed a weak cooling trend. For temperate meadow, about 72.2 and 72.6 % of surface cooling were explained by both grassland type and increase of vegetation cover for August and September, respectively. For temperate steppe and temperate desert steppe, due to the limited soil moisture and little evaporative cooling feedback, the vegetation changes have no significant effect on the surface air temperature. These results indicate that the impact of grassland types and vegetation cover changes should be considered when projecting further climate change in the temperate grassland region of China.

  4. Jardines residenciales en Santiago de Chile: Extensión, distribución y cobertura vegetal Residential gardens of Santiago, Chile: Extent, distribution and vegetation cover

    Directory of Open Access Journals (Sweden)

    SONIA REYES-PAECKE

    2011-12-01

    Full Text Available Los jardines residenciales aportan una gran cobertura vegetacional en ambientes urbanos, pero han sido poco estudiados en América Latina. Este es el primer estudio sobre la materia realizado en el Área Metropolitana de Santiago (AMS. En esta ciudad los jardines residenciales cubren el 26 % de la superficie urbana. Aunque la muestra analizada (n = 7236 evidencia una gran dispersión de tamaños, el 56 % de los jardines mide entre 74 y 268 m². El 37 % de la superficie de los jardines está cubierta de árboles y arbustos, seguido por césped (34 %, edificaciones menores (26 % y solo un 3.0 % carece de cobertura. Hay una alta correlación entre tamaño predial y cobertura vegetal (R² = 0.97, excepto en el centro de la ciudad, en donde a mayor tamaño predial se incrementa la superficie edificada y por tanto los jardines son pequeños. La cobertura vegetal total de los jardines residenciales alcanza 12000 hectáreas, equivalente al 19 % del AMS, lo cual es 3.7 veces mayor a la superficie de áreas verdes públicas. Los factores más influyentes en la cobertura y estructura de la vegetación de los jardines, son el tamaño predial y la tipología de edificación.Residential gardens provide important vegetation cover in urban environments but there is little research in Latin America. This is the first study on the subject in Santiago de Chile. In Santiago 26 % of the urban area is covered by residential gardens. Even though there is a wide range of residential garden size, most of them measure between 74268 m². The garden surface is mainly covered by trees and shrubs (37 %, followed by lawn (34 %, small buildings (26 % while only 3 % have no vegetation cover at all. A high correlation between lot size and vegetation cover was detected (R² = 0.97 except for the city centre where the increase in lot size is associated with an increase in the built up area. The vegetation cover of residential gardens reaches 12000 hectares (19 % of the urban area

  5. Population Genetic Structure of the Giant Cactus Echinopsis terscheckii in Northwestern Argentina Is Shaped by Patterns of Vegetation Cover.

    Science.gov (United States)

    Quipildor, Vilma B; Mathiasen, Paula; Premoli, Andrea C

    2017-07-01

    Species inhabiting drylands commonly depend on the surrounding vegetation for recruitment under stress, while competition may affect populations in moister environments. Our objective was to analyze how different climates and vegetation affect the fine-scale spatial genetic structure (SGS) of the columnar cactus Echinopsis terscheckii. At 4 sites, we estimated vegetation cover by digitized patches and the normalized difference vegetation index (NDVI). We mapped 30 individuals per population and collected tissue for isozyme electrophoresis using 15 putative loci. Spatial autocorrelation between all possible genotype pairs and the number of genetically homogeneous groups and families were calculated for each population. Greater cover (66%) and average NDVI values were detected in the most humid habitat that consisted of fewer, larger, and more dispersed vegetation patches. All populations were genetically diverse and showed significant SGS. Positive correlations were found between the distance at which maximum autocorrelation and kinship values were reached and vegetation area and patch size. Also higher NDVI values were associated with lower number of patches. Populations exposed to higher precipitation and vegetation cover consisted of sparse individuals that clustered at larger distances whereas vegetation patches in arid climates produced groups of closely related genotypes at small distances. These results support the stress-gradient genetic hypothesis. Under water stress, facilitation promotes establishment underneath patchy vegetation resulting in fine-scale family structure. In moister xerophilous forests, competition for resources, that is, light, results in sparse individuals and thus coarse-scale neighborhoods. This information can guide conservation and/or restoration efforts, such as the spatial scale to be considered in germplasm collection. © The American Genetic Association 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. Geomorphometric correlations of vegetation cover properties and topographic karst features based on high-resolution LiDAR DTM of Aggtelek Karst, NE Hungary

    Science.gov (United States)

    Székely, Balázs; Telbisz, Tamás; Koma, Zsófia; Kelemen, Kristóf; Szmorad, Ferenc; Deák, Márton; Látos, Tamás; Standovár, Tibor

    2015-04-01

    Topography and lithology are two major factors influencing the vegetation cover, its mosaic pattern and lateral transitions. In karstic areas the topography has a high diversity, microtopographic landforms influence the local ecological setting, vegetation structure. Presence of sinkholes of various sizes and geometric arrangements causes rapid lateral variation of the slope, aspect patterns as well as highly modify the soil water balance in time and space. These diversity of factors defines a mosaicked habitat pattern for vegetation assemblages. The World Heritage Site Aggtelek Karst/Slovakian Karst Caves has characteristic natural and environmental properties concerning the geomorphological as well as the ecological values. In order to be able to study the topographic influence on the ecological setting, a high-resolution digital terrain model (DTM) and digital surface model (DSM) have been derived from airborne laser scanning data depicting the karstic micro- and macrotopographic Landscape elements and the envelope surface of the canopy. Additional vegetation parameters like closure and average height have been derived from a normalized digital surface model (nDSM). Extensive mapping of vegetation properties has been carried out: centered on points of a grid array several vegetation-specific data - including composition and structure of tree and shrub layers, herbacesous vegetation and tree regeneration - have been acquired. Various classification patterns - based on trees pecies composition, vertical vegetation structure - have been derived from this data set. The comparison of the vegetation classification data and the geomorphometric DTM derivatives yielded interesting results. Certain vegetation characteristics often correlate with the geomorphometric properties. We interpret this similarity as sensitivity of vegetion to fine-scale variations in geomorphic properties like aspect, illumination conditions and soil properties. However, in many cases the

  7. 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.

  8. Modelling Vegetation Cover Dynamics of the Niger Floodplain in Mali, Westafrica, Using Multitemporal MERIS Full Resolution and TERRA -ASTER Data

    Science.gov (United States)

    Seiler, Ralf

    This presentation aims at showing the potential of a combined use of multi-temporal data from two different sensors (MERIS and TERRA ASTER) for an analysis of vegetation cover changes in semi-arid environments. While MERIS data mainly provide information about the vegetation cover density, ASTER data were used to analyse soil properties -especially soil brightness and soil wetness. An algorithm is proposed that uses atmospherically corrected surface reflectance values from MERIS and ASTER measurements. These values are subsequently splitted into a signal component that is caused by the vegetation cover and the background component (triggered by soil properties) using a linear spectral unmixing approach. Vegetation cover then is described by Vegetation Indices (MGVI, NDVI / SAVI) that were calculated from the vegetation signal component. Finally, these vegetation parameter were classified for all multi-temporal MERIS data using the EM algorithm to derive the temporal behaviour of vegetation pattern at the Inland Delta. The algorithm provides, as results, a fractional vegetation cover, a vegetation density value and information on the soil type. A detailed mapping of the spatio-temporal vegetation cover patterns for the Niger Inland Delta during the period of 2002 -2005 is another outcome of this study in addition to an in-depth evaluation of the applicability of the used VIs for environments with sparse vegetation covers. Located in the western Sahel of Africa, (1330' N -17 N and 230' W -530' W), the Niger Inland Delta is one of the largest floodplains in the world. The geographic term "Niger Inland Delta" represents a vast, extremely flat area of around 40.000 km extend, which is annually inundated by water of the Niger -Bani riversystem. In contrast to its semi -arid surrounding, the delta's ecology can be described as a mosaic of permanent, periodical and episodically flooded areas. Their extend varies both in scale and time due to irregularities of amount as

  9. Development and Interpretation of New Sediment Rating Curve Considering the Effect of Vegetation Cover for Asian Basins

    Directory of Open Access Journals (Sweden)

    Jie Wang

    2013-01-01

    Full Text Available Suspended sediment concentration of a river can provide very important perspective on erosion or soil loss of one river basin ecosystem. The changes of land use and land cover, such as deforestation or afforestation, affect sediment yield process of a catchment through changing the hydrological cycle of the area. A sediment rating curve can describe the average relation between discharge and suspended sediment concentration for a certain location. However, the sediment load of a river is likely to be undersimulated from water discharge using least squares regression of log-transformed variables and the sediment rating curve does not consider temporal changes of vegetation cover. The Normalized Difference Vegetation Index (NDVI can well be used to analyze the status of the vegetation cover well. Thus long time monthly NDVI data was used to detect vegetation change in the past 19 years in this study. Then monthly suspended sediment concentration and discharge from 1988 to 2006 in Laichau station were used to develop one new sediment rating curve and were validated in other Asian basins. The new sediment model can describe the relationship among sediment yield, streamflow, and vegetation cover, which can be the basis for soil conservation and sustainable ecosystem management.

  10. 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.

  11. Using Unmanned Aerial Vehicles to Assess Vegetative Cover and Identify Biotic Resources in Sagebrush Steppe Ecosystems: Preliminary Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Robert P. Breckenridge

    2006-04-01

    The Idaho National Laboratory (INL), in conjunction with the University of Idaho, is evaluating novel approaches for using unmanned aerial vehicles (UAVs) as a quicker and safer method for monitoring biotic resources. Evaluating vegetative cover is an important factor in understanding the sustainability of many ecosystems. In assessing vegetative cover, methods that improve accuracy and cost efficiency could revolutionize how biotic resources are monitored on western federal lands. Sagebrush steppe ecosystems provide important habitat for a variety of species, some of which are important indicator species (e.g., sage grouse). Improved methods are needed to support monitoring these habitats because there are not enough resource specialists or funds available for comprehensive ground evaluation of these ecosystems. In this project, two types of UAV platforms (fixed wing and helicopter) were used to collect still-frame imagery to assess cover in sagebrush steppe ecosystems. This paper discusses the process for collecting and analyzing imagery from the UAVs to (1) estimate total percent cover, (2) estimate percent cover for six different types of vegetation, and (3) locate sage grouse based on representative decoys. The field plots were located on the INL site west of Idaho Falls, Idaho, in areas with varying amounts and types of vegetative cover. A software program called SamplePoint developed by the U.S. Department of Agriculture, Agricultural Research Service was used to evaluate the imagery for percent cover for the six vegetation types (bare ground, litter, shrubs, dead shrubs, grasses, and forbs). Results were compared against standard field measurements to assess accuracy.

  12. Pollen-based quantitative reconstructions of Holocene regional vegetation cover (plant-functional types and land-cover types) in Europe suitable for climate modelling.

    Science.gov (United States)

    Trondman, A-K; Gaillard, M-J; Mazier, F; Sugita, S; Fyfe, R; Nielsen, A B; Twiddle, C; Barratt, P; Birks, H J B; Bjune, A E; Björkman, L; Broström, A; Caseldine, C; David, R; Dodson, J; Dörfler, W; Fischer, E; van Geel, B; Giesecke, T; Hultberg, T; Kalnina, L; Kangur, M; van der Knaap, P; Koff, T; Kuneš, P; Lagerås, P; Latałowa, M; Lechterbeck, J; Leroyer, C; Leydet, M; Lindbladh, M; Marquer, L; Mitchell, F J G; Odgaard, B V; Peglar, S M; Persson, T; Poska, A; Rösch, M; Seppä, H; Veski, S; Wick, L

    2015-02-01

    We present quantitative reconstructions of regional vegetation cover in north-western Europe, western Europe north of the Alps, and eastern Europe for five time windows in the Holocene [around 6k, 3k, 0.5k, 0.2k, and 0.05k calendar years before present (bp)] at a 1° × 1° spatial scale with the objective of producing vegetation descriptions suitable for climate modelling. The REVEALS model was applied on 636 pollen records from lakes and bogs to reconstruct the past cover of 25 plant taxa grouped into 10 plant-functional types and three land-cover types [evergreen trees, summer-green (deciduous) trees, and open land]. The model corrects for some of the biases in pollen percentages by using pollen productivity estimates and fall speeds of pollen, and by applying simple but robust models of pollen dispersal and deposition. The emerging patterns of tree migration and deforestation between 6k bp and modern time in the REVEALS estimates agree with our general understanding of the vegetation history of Europe based on pollen percentages. However, the degree of anthropogenic deforestation (i.e. cover of cultivated and grazing land) at 3k, 0.5k, and 0.2k bp is significantly higher than deduced from pollen percentages. This is also the case at 6k in some parts of Europe, in particular Britain and Ireland. Furthermore, the relationship between summer-green and evergreen trees, and between individual tree taxa, differs significantly when expressed as pollen percentages or as REVEALS estimates of tree cover. For instance, when Pinus is dominant over Picea as pollen percentages, Picea is dominant over Pinus as REVEALS estimates. These differences play a major role in the reconstruction of European landscapes and for the study of land cover-climate interactions, biodiversity and human resources. © 2014 The Authors Global Change Biology Published by John Wiley & Sons Ltd.

  13. Vegetation height and cover fraction between 60° S and 60° N from ICESat GLAS data

    Science.gov (United States)

    Los, S. O.; Rosette, J. A. B.; Kljun, N.; North, P. R. J.; Chasmer, L.; Suárez, J. C.; Hopkinson, C.; Hill, R. A.; van Gorsel, E.; Mahoney, C.; Berni, J. A. J.

    2012-03-01

    We present new coarse resolution (0.5° × 0.5°) vegetation height and vegetation-cover fraction data sets between 60° S and 60° N for use in climate models and ecological models. The data sets are derived from 2003-2009 measurements collected by the Geoscience Laser Altimeter System (GLAS) on the Ice, Cloud and land Elevation Satellite (ICESat), the only LiDAR instrument that provides close to global coverage. Initial vegetation height is calculated from GLAS data using a development of the model of Rosette et al. (2008) with with further calibration on desert sites. Filters are developed to identify and eliminate spurious observations in the GLAS data, e.g. data that are affected by clouds, atmosphere and terrain and as such result in erroneous estimates of vegetation height or vegetation cover. Filtered GLAS vegetation height estimates are aggregated in histograms from 0 to 70 m in 0.5 m intervals for each 0.5° × 0.5°. The GLAS vegetation height product is evaluated in four ways. Firstly, the Vegetation height data and data filters are evaluated using aircraft LiDAR measurements of the same for ten sites in the Americas, Europe, and Australia. Application of filters to the GLAS vegetation height estimates increases the correlation with aircraft data from r = 0.33 to r = 0.78, decreases the root-mean-square error by a factor 3 to about 6 m (RMSE) or 4.5 m (68% error distribution) and decreases the bias from 5.7 m to -1.3 m. Secondly, the global aggregated GLAS vegetation height product is tested for sensitivity towards the choice of data quality filters; areas with frequent cloud cover and areas with steep terrain are the most sensitive to the choice of thresholds for the filters. The changes in height estimates by applying different filters are, for the main part, smaller than the overall uncertainty of 4.5-6 m established from the site measurements. Thirdly, the GLAS global vegetation height product is compared with a global vegetation height product

  14. Use of satellite imagery to identify vegetation cover changes following the Waldo Canyon Fire event, Colorado, 2012-2013

    Science.gov (United States)

    Cole, Christopher J.; Friesen, Beverly A.; Wilson, Earl M.

    2014-01-01

    The Waldo Canyon Fire of 2012 was one of the most destructive wildfire events in Colorado history. The fire burned a total of 18,247 acres, claimed 2 lives, and destroyed 347 homes. The Waldo Canyon Fire continues to pose challenges to nearby communities. In a preliminary emergency assessment conducted in 2012, the U.S. Geological Survey (USGS) concluded that drainage basins within and near the area affected by the Waldo Canyon Fire pose a risk for future debris flow events. Rainfall over burned, formerly vegetated surfaces resulted in multiple flood and debris flow events that affected the cities of Colorado Springs and Manitou Springs in 2013. One fatality resulted from a mudslide near Manitou Springs in August 2013. Federal, State, and local governments continue to monitor these hazards and other post-fire effects, along with the region’s ecological recovery. At the request of the Colorado Springs Office of Emergency Management, the USGS Special Applications Science Center developed a geospatial product to identify vegetation cover changes following the 2012 Waldo Canyon Fire event. Vegetation cover was derived from July 2012 WorldView-2 and September 2013 QuickBird multispectral imagery at a spatial resolution of two meters. The 2012 image was collected after the fire had reached its maximum extent. Per-pixel increases and decreases in vegetation cover were identified by measuring spectral changes that occurred between the 2012 and 2013 image dates. A Normalized Difference Vegetation Index (NDVI), and Green-Near Infrared Index (GRNIR) were computed from each image. These spectral indices are commonly used to characterize vegetation cover and health condition, due to their sensitivity to detect foliar chlorophyll content. Vector polygons identifying surface-cover feature boundaries were derived from the 2013 imagery using image segmentation software. This geographic software groups similar image pixels into vector objects based upon their spatial and spectral

  15. Large-scale assessment of soil erosion in Africa: satellites help to jointly account for dynamic rainfall and vegetation cover

    Science.gov (United States)

    Vrieling, Anton; Hoedjes, Joost C. B.; van der Velde, Marijn

    2015-04-01

    Efforts to map and monitor soil erosion need to account for the erratic nature of the soil erosion process. Soil erosion by water occurs on sloped terrain when erosive rainfall and consequent surface runoff impact soils that are not well-protected by vegetation or other soil protective measures. Both rainfall erosivity and vegetation cover are highly variable through space and time. Due to data paucity and the relative ease of spatially overlaying geographical data layers into existing models like USLE (Universal Soil Loss Equation), many studies and mapping efforts merely use average annual values for erosivity and vegetation cover as input. We first show that rainfall erosivity can be estimated from satellite precipitation data. We obtained average annual erosivity estimates from 15 yr of 3-hourly TRMM Multi-satellite Precipitation Analysis (TMPA) data (1998-2012) using intensity-erosivity relationships. Our estimates showed a positive correlation (r = 0.84) with long-term annual erosivity values of 37 stations obtained from literature. Using these TMPA erosivity retrievals, we demonstrate the large interannual variability, with maximum annual erosivity often exceeding two to three times the mean value, especially in semi-arid areas. We then calculate erosivity at a 10-daily time-step and combine this with vegetation cover development for selected locations in Africa using NDVI - normalized difference vegetation index - time series from SPOT VEGETATION. Although we do not integrate the data at this point, the joint analysis of both variables stresses the need for joint accounting for erosivity and vegetation cover for large-scale erosion assessment and monitoring.

  16. ASSESSMENT OF VEGETATION COVER ON SODA WASTE DISPOSAL SITE AT JANIKOWO, FOLLOWING 13-YEAR-LONG RECLAMATION

    Directory of Open Access Journals (Sweden)

    Kazimierz Henryk Dyguś

    2014-10-01

    Full Text Available The results are presented of vegetation survey on the alkaline and saline soda waste disposal site at Janikowo Soda Plant near Toruń (central Poland. The site was subject to reclamation using diverse techniques including sewage sludge and ash, starting from the year 2000 onwards. The survey was made to evaluate the status of plant succession as well as stability and diversity of vegetation cover. The vegetation was inventoried using the cover-frequency method, on a 10 x 10 m quadrat samples randomly distributed over the reclaimed area. Communities were classified using the Central-European approach by Braun-Blanquet (1964. In 2013, the vegetation was well established and provided a dense cover of the substrate. 108 plant species were found compared to some 5–8 plants which arrived spontaneously until the year 2000. Species richness increased 15 fold since the year when reclamation started. Species of graminoid and Asteraceae families prevailed in most patches of local vegetation. The vegetation cover on sites treated with a mixt of power plant ash and sewage sludge was less stable and less diverse than that on sites where sewage sludge only was applied. Annuals and biennials dominated in the vegetation on ash grounds while more competitive perennials prevailed on sewage sludge substrates. On the latter substrates there develop plant communities classified as an association of smooth meadow grass and common yarrow Poa pratensis-Achillea millefolium, whose species combination closely resembles that of seminatural fresh meadows. On the ash grounds, a variety of associations of ruderal plants were found with dominating Loesel mustard and common mugwort Sisymbrium loeselii-Artemisia vulgaris. Phytoindicatory methods using Ellenberg values have shown that waste substrates contained increased salt concentrations, however, there was no indication of increased heavy metal contents, as no plants tolerating excessive amounts of heavy metals were

  17. Analysis to efficiency discrete covering worker organ when clearing vegetable raw material

    Directory of Open Access Journals (Sweden)

    G. V. Alekseev

    2016-01-01

    Full Text Available In article is executed analysis to efficiency of the functioning the cleansing equipment for different type vegetable cheese: potatoes, carrot, pommel and the other type potatoes. He is indicative of that that much of the cleansing equipment uses as worker organ abrasive put, which improvement is one of the directions of increasing to his efficiency and improvements of his field-performance data. Classical model of the motion club is considered In process of the analysis in camera of the cleansing machine. For optimization of the process peelings is installed path of the motion and is calculated corner of the flight club with cone-shaped chalice. When shaping the models is considered apart taken tuber of the potatoes. Expecting his uniform sphere and without regard influence upon it other club, have defined the path of his motion on cone-shaped chalice and corner, under which tuber flies to wall. The Corner of the slopping cone chalices 30 degrees took to horizon. Integrating equation on time, got the equation of the energy balance, from which possible select required for peelings time. The Further analysis conducted the methods of the numerical experiment in system Mathcad. Got in this experiment results allow to optimize the drawing a fixing abrasive bands, taking into consideration designed methods of the shaping for such object, as worker organs cleansing machines, technology of the intermittent fixing covering. The Following stage of modeling expected consideration of the process peelings for collection cleaned club, on which expected the separate cleaned objects (for instance, potato tubers springy element, changing their (in flat production hard disk united between itself springy spring. Consideration this elaborated models have allowed to install the frequencies of the free fluctuations of this system and, accordingly, moments of the osculation worker organ that in significant measure defines the topology of the abrasive covering.

  18. Holocene vegetation cover in Qin'an area of western Chinese Loess Plateau revealed by n-alkane

    Institute of Scientific and Technical Information of China (English)

    ZHONG YanXia; CHEN FaHu; AN ChengBang; XIE ShuCheng; HUANG XianYu

    2007-01-01

    Previous studies have found that wetlands prevailed in western Chinese Loess Plateau and pine pollen could reach up to 80% in Qin'an area of the plateau during middle Holocene.It was then deduced that forest vegetation covered Qin'an area in a warm and wet climate during middle Holocene.The proxies of molecule biomarkers from two Holocene sections,a swamp-alluvial loess section and a typical loess-paleosol section are used to reconstruct regional vegetation history.It is found that the heavy-molecular-weight(HMW)homologues of the n-alkanes in all samples exhibit a pronounced odd-over-even predominance,maximizing at C31 and the abundance of the nC27-alkanes is the lowest in nC27,nC29,nC31,i.e.C27<C29<C31,a typical grass n-alkanes model.The results are the same as those of model surface soil samples under grass cover but different from both forest cover and modern pine leaves,which yield preferentially nC29-alkanes peak.It could be jnferred that the area was dominated by grass cover but not forest cover during whole Holocene epoch.The study shows that combining both molecule biomarkers and pollen analysis can avoid the disadvantage of pollen analysis in reconstruction of regional vegetation cover.

  19. Modeled Impacts of Cover Crops and Vegetative Barriers on Corn Stover Availability and Soil Quality

    Energy Technology Data Exchange (ETDEWEB)

    Ian J. Bonner; David J. Muth Jr.; Joshua B. Koch; Douglas L. Karlen

    2014-06-01

    Environmentally benign, economically viable, and socially acceptable agronomic strategies are needed to launch a sustainable lignocellulosic biofuel industry. Our objective was to demonstrate a landscape planning process that can ensure adequate supplies of corn (Zea mays L.) stover feedstock while protecting and improving soil quality. The Landscape Environmental Assessment Framework (LEAF) was used to develop land use strategies that were then scaled up for five U.S. Corn Belt states (Nebraska, Iowa, Illinois, Indiana, and Minnesota) to illustrate the impact that could be achieved. Our results show an annual sustainable stover supply of 194 million Mg without exceeding soil erosion T values or depleting soil organic carbon [i.e., soil conditioning index (SCI)?>?0] when no-till, winter cover crop, and vegetative barriers were incorporated into the landscape. A second, more rigorous conservation target was set to enhance soil quality while sustainably harvesting stover. By requiring erosion to be <1/2 T and the SCI-organic matter (OM) subfactor to be >?0, the annual sustainable quantity of harvestable stover dropped to148 million Mg. Examining removal rates by state and soil resource showed that soil capability class and slope generally determined the effectiveness of the three conservation practices and the resulting sustainable harvest rate. This emphasizes that sustainable biomass harvest must be based on subfield management decisions to ensure soil resources are conserved or enhanced, while providing sufficient biomass feedstock to support the economic growth of bioenergy enterprises.

  20. Comparison of revegetation techniques on mineral clay soil: analysis of quantitative response of vegetation cover

    Directory of Open Access Journals (Sweden)

    Enrico Muzzi

    2016-08-01

    Full Text Available Revegetation of mineral-clay soils is a notably complex ecological and technically challenging undertaking that depends on substrate profile and local micro-environmental conditions, factors making it a particularly long procedure as well. This study compared and assessed the medium-term effectiveness of four treatments employed to promote stable pedogenesis and herbaceous recolonisation of abandoned clay quarries in the Apennine foothills of northern Italy’s Emilia- Romagna region. The treatments included: slow-release N organic fertiliser, phosphate fertiliser, organic amendment and topsoil [the soil top layer (0-0.2 m of a local natural meadow]. The state of the vegetative cover was monitored monthly from 1994 through 2004, until problems of slope stability at the site compromised the integrity of the trial plots. Significant effects were achieved by the recycled topsoil through 8 years and by organic amendment through 6 years; the effects of slow-release nitrogen were notably limited over time and phosphorous delivered a medium-term response but of notable year-toyear swings. No interactions among factors emerged in the mediumterm. After 11 years, treatments did not induce effects statistical appreciable. Our results suggest that the tested agronomic strategies on mineral clay soil did not trigger, in the medium-term, secondary succession processes able to potentially alter the spontaneous revegetation course.

  1. The effect of wind and precipitation on vegetation and biogenic crust covers in the Sde-Hallamish sand dunes

    Science.gov (United States)

    Amir, Raz; Kinast, Shai; Tsoar, Haim; Yizhaq, Hezi; Zaady, Eli; Ashkenazy, Yosef

    2014-03-01

    Vegetation and biogenic crust covers play an important role in sand dune stabilization, yet there is a lack of high temporal and spatial resolution data on sand dune cover. A field experiment, aimed at measuring the dynamics of biogenic crust and vegetation in sand dunes, was conducted at the Sde-Hallamish sand dunes in the northwestern Negev Desert, Israel, from July 2008 to August 2010. The climate of the Sde-Hallamish sand dunes is arid (the mean annual precipitation over the past 13 years is 61 mm), and the dunes are linear and partially stable, mainly due to the presence of biogenic crust and partially due to the presence of vegetation. In July 2008, 10×10 m plots on the four dune habitats (crest, interdune, north slope, and south slope) were treated as follows: (i) removal of vegetation and biogenic crust, (ii) removal of biogenic crust only, (iii) removal of vegetation only, (iv) partial removal of biogenic crust and vegetation, and (v) control plot. The surface coverage of sand, biogenic crust, and vegetation was monitored on a monthly basis, using a remote-sensing technique especially developed for the Sde-Hallamish sand dunes. It was found that strong wind events, with durations of several days, accounted for the coverage changes in biogenic crust and vegetation. The response to precipitation was much slower. In addition, no rehabilitation of biogenic crust and vegetation was observed within the experiment time period. The changes in biogenic crust cover were not necessarily related to changes in dune dynamics, since often an increase in biogenic crust cover is a result of wind erosion that exposes old crust that was buried under the sand; wind hardly erodes biogenic crust at all due to its high durability to wind action. The Sde-Hallamish dunes seem to have become more active as a result of a prolonged drought during the past several years. The field experiment reported here indicates that biogenic crust cover exhibits large seasonal variations that are

  2. A comparison of cover calculation techniques for relating point-intercept vegetation sampling to remote sensing imagery

    Science.gov (United States)

    Accurate and timely spatial predictions of vegetation cover from remote imagery are an important data source for natural resource management. High-quality in situ data are needed to develop and validate these products. Point-intercept sampling techniques are a common method for obtaining quantitativ...

  3. Vegetation dynamics, and land use and land cover change in the Bale Mountains, Ethiopia.

    Science.gov (United States)

    Kidane, Yohannes; Stahlmann, Reinhold; Beierkuhnlein, Carl

    2012-12-01

    Shifts in biological communities are occurring at rapid rates as human activities induced global climate change increases. Understanding the effects of the change on biodiversity is important to reduce loss of biodiversity and mass extinction, and to insure the long-term persistence of natural resources and natures' services. Especially in remote landscapes of developing countries, precise knowledge about on-going processes is scarce. Here we apply satellite imagery to assess spatio-temporal land use and land cover change (LULCC) in the Bale Mountains for a period of four decades. This study aims to identify the main drivers of change in vegetation patterns and to discuss the implications of LULCC on spatial arrangements and trajectories of floral communities. Remote sensing data acquired from Landsat MSS, Landsat ETM + and SPOT for four time steps (1973, 1987, 2000, and 2008) were analyzed using 11 LULC units defined based on the dominant plant taxa and cover types of the habitat. Change detection matrices revealed that over the last 40 years, the area has changed from a quite natural to a more cultural landscape. Within a representative subset of the study area (7,957.5 km(-2)), agricultural fields have increased from 1.71% to 9.34% of the total study area since 1973. Natural habitats such as upper montane forest, afroalpine grasslands, afromontane dwarf shrubs and herbaceous formations, and water bodies also increased. Conversely, afromontane grasslands have decreased in size by more than half (going from 19.3% to 8.77%). Closed Erica forest also shrank from 15.0% to 12.37%, and isolated Erica shrubs have decreased from 6.86% to 5.55%, and afroalpine dwarf shrubs and herbaceous formations reduced from 5.2% to 1.56%. Despite fluctuations the afromontane rainforest (Harenna forest), located south of the Bale Mountains, has remained relatively stable. In conclusion this study documents a rapid and ecosystem-specific change of this biodiversity hotspot due to

  4. Influence of Vegetation Cover on Rain Pulse Responses in Semi-Arid Savannas in Central Texas

    Science.gov (United States)

    Litvak, M.; Heilman, J.; McInnes, K.; Thijs, A.; Kjelgaard, J.

    2007-12-01

    Savannas in central Texas are dominated by live oak (Quercus virginiana) and Ashe juniper (Juniperus asheii) underlain by perennial, C3/C4 grasslands, and are increasingly becoming juniper and mesquite dominated due to overgrazing and suppression of wildfires. Since 2004, we have been investigating how carbon, water and energy exchange in these rain-limited savannas respond to rainfall variability and this observed vegetation change. In semi-arid regions, rainfall pulses provide inputs of soil moisture and trigger biotic activity in the form of plant gas exchange and microbial metabolism as well as water dependent physical processes in the soil. Each of these components has a different characteristic response curve to soil moisture and integrates soil water content over a different range of depths. Here we focus on examining how the observed increase of woody species in central Texas savannas alters the response of net ecosystem exchange and its components, ecosystem respiration and gross ecosystem exchange, to rain pulses. Using data we have collected over the last three years from three Ameriflux tower sites at Freeman Ranch near San Marcos, TX (C3/C4 grassland, juniper/mesquite savanna with 50 percent woody cover, and oak/juniper woodland), we quantify the responses of both ecosystem respiration and daily carbon uptake to rainfall pulses throughout the year. Specifically, we look at the enhancement and persistence of ecosystem respiration and carbon uptake responses following a pulse, and isolate the main controlling factors on the observed response: seasonality, antecedent soil moisture and temperature, or previous pulses. In all three land covers, the general response to precipitation pulses is a respiration pulse followed by an increase in total carbon uptake. Differences in pulse responses observed at the savanna site compared to the grassland and woodland sites can be explained, in part, by the observed differences in rooting structure and photosynthetic

  5. The Influence of Vegetation Cover on Summer Precipitation in China: a Statistical Analysis of NDVI and Climate Data

    Institute of Scientific and Technical Information of China (English)

    张井勇; 董文杰; 符淙斌; 吴凌云

    2003-01-01

    This study provides new evidence for the feedback effects of vegetation cover on summer precipitation in different regions of China by calculating immediate (same season), and one-and two-season lagged correlations between the normalized difference vegetation index (NDVI) and summer precipitation. The results show that the correlation coefficients between NDVI in spring and the previous winter and precipitation in summer are positive in most regions of China, and they show significant difference between regions. The stronger one-and two-season lagged correlations occur in the eastern arid/semi-arid region, Central China,and Southwest China out of the eight climatic regions of China, and this implies that vegetation cover change has more sensitive feedback effects on summer precipitation in the three regions. The three regions are defined as sensitive regions. Spatial analyses of correlations between spring NDVI averaged over each sensitive region and summer precipitation of 160 stations suggest that the vegetation cover strongly affects summer precipitation not only over the sensitive region itself but also over other regions, especially the downstream region.

  6. Thermal remote sensing of surface soil water content with partial vegetation cover for incorporation into climate models

    Science.gov (United States)

    Gillies, Robert R.; Carlson, Toby N.

    1995-01-01

    This study outlines a method for the estimation of regional patterns of surface moisture availability (M(sub 0)) and fractional vegetation (Fr) in the presence of spatially variable vegetation cover. The method requires relating variations in satellite-derived (NOAA, Advanced Very High Resolution Radiometer (AVHRR)) surface radiant temperature to a vegetation index (computed from satellite visible and near-infrared data) while coupling this association to an inverse modeling scheme. More than merely furnishing surface soil moisture values, the method constitues a new conceptual and practical approach for combining thermal infrared and vegetation index measurements for incorporating the derived values of M(sub 0) into hydrologic and atmospheric prediction models. Application of the technique is demonstrated for a region in and around the city of Newcastle upon Tyne situated in the northeast of England. A regional estimate of M(sub 0) is derived and is probabbly good for fractional vegetation cover up to 80% before errors in the estimated soil water content become unacceptably large. Moreover, a normalization scheme is suggested from which a nomogram, `universal triangle,' is constructed and is seen to fit the observed data well. The universal triangle also simplifies the inclusion of remotely derived M(sub 0) in hydrology and meteorological models and is perhaps a practicable step toward integrating derived data from satellite measurements in weather forecasting.

  7. Thermal remote sensing of surface soil water content with partial vegetation cover for incorporation into climate models

    Science.gov (United States)

    Gillies, Robert R.; Carlson, Toby N.

    1995-01-01

    This study outlines a method for the estimation of regional patterns of surface moisture availability (M(sub 0)) and fractional vegetation (Fr) in the presence of spatially variable vegetation cover. The method requires relating variations in satellite-derived (NOAA, Advanced Very High Resolution Radiometer (AVHRR)) surface radiant temperature to a vegetation index (computed from satellite visible and near-infrared data) while coupling this association to an inverse modeling scheme. More than merely furnishing surface soil moisture values, the method constitues a new conceptual and practical approach for combining thermal infrared and vegetation index measurements for incorporating the derived values of M(sub 0) into hydrologic and atmospheric prediction models. Application of the technique is demonstrated for a region in and around the city of Newcastle upon Tyne situated in the northeast of England. A regional estimate of M(sub 0) is derived and is probabbly good for fractional vegetation cover up to 80% before errors in the estimated soil water content become unacceptably large. Moreover, a normalization scheme is suggested from which a nomogram, `universal triangle,' is constructed and is seen to fit the observed data well. The universal triangle also simplifies the inclusion of remotely derived M(sub 0) in hydrology and meteorological models and is perhaps a practicable step toward integrating derived data from satellite measurements in weather forecasting.

  8. Alterations in fruit and vegetable beta-carotene and vitamin C content caused by open-sun drying, visqueen-covered and polyethylene-covered solar-dryers.

    Science.gov (United States)

    Ndawula, J; Kabasa, J D; Byaruhanga, Y B

    2004-08-01

    This study investigated the effects of three drying methods (open sun drying, visqueen-covered solar dryer and polyethylene-covered solar dryer) on b-carotene and vitamin C content of edible portions of mango fruit (Mangifera indica) and cowpea leaves (Vigna unguiculata). Commercial samples were analysed for vitamin C by titrimetry and b-carotene by spectrophotometry at 450 nm. Differences in vitamin retention and loss associated with the three drying methods were assessed by analysis of variance and least significant difference (LSD) at (pdrying. Open sun drying method caused the greatest b-carotene and vitamin C loss (58% and 84% respectively), while the visqueen-covered solar dryer caused the least loss (34.5% and 71% respectively). Blanching cowpea leaves improved b-carotene and vitamin C retention by 15% and 7.5% respectively. The b-carotene and vitamin C content of fresh ripe mango fruit was 5.9 and 164.3 mg/100g DM respectively. Similar to effects on cowpea leaves, the mango micronutrient content decreased (pdrying. The open sun drying method caused the greatest b-carotene (94.2%) and vitamin C (84.5%) loss, while the visqueen-covered solar dryer caused the least (73 and 53% respectively). These results show that the three solar drying methods cause significant loss of pro-vitamin A and vitamin C in dried fruits and vegetables. However, open sun drying causes the most loss and the visqueen-covered solar dryer the least, making the later a probable better drying technology for fruit and vegetable preservation. The drying technologies should be improved to enhance vitamin retention.

  9. Separation and Extension of Cover Inequalities for Conic Quadratic Knapsack Constraints with Generalized Upper Bounds

    DEFF Research Database (Denmark)

    Atamtürk, Alper; Muller, Laurent Flindt; Pisinger, David

    2013-01-01

    Motivated by addressing probabilistic 0-1 programs we study the conic quadratic knapsack polytope with generalized upper bound (GUB) constraints. In particular, we investigate separating and extending GUB cover inequalities. We show that, unlike in the linear case, determining whether a cover can....... These experiments show that a judicious application of the extended GUB cover cuts can reduce the solution time of conic quadratic 0-1 programs with GUB constraints substantially. © 2013 INFORMS....

  10. Effect of vegetal cover on runoff and soil erosion under light intensity events. Rainfall simulation over USLE plots.

    Science.gov (United States)

    Marques, María José; Bienes, Ramón; Jiménez, Luis; Pérez-Rodríguez, Raquel

    2007-05-25

    The erosive power of frequent light rainfalls is studied in this paper. Field experiments of simulated rainfall (Intensity, 21 mm h(-1) and kinetic energy, 13.5 J m(-2) mm(-1)) were conducted over 8 bounded USLE plots (80 m(2) each) with a slope of 10%. In 4 plots the soil was almost bare (<4% vegetation cover); the other 4 plots had almost full cover with natural vegetation in one year. Runoff and sediment yield was recorded. The results revealed the efficiency of vegetation cover reducing runoff and sediments. Runoff and sediments were negligible in covered plots. Therefore, in bare plots, although sediment yield was generally low, averaging 74+/-43 kg ha(-1), the mean of runoff achieved a coefficient of 35%, this magnitude has to be taken into consideration in this region verging on aridity. Rains around 13.5 J m(-2) mm(-1) of kinetic energy are quite frequent in the study area (34% of recorded rains en 12 years). If we would consider the usual lower limits from the literature, we would be ignoring an important percent of natural rainfall episodes.

  11. Monitoring vegetation cover in the postfire in Tavira - São Brás de Alportel (southern Portugal)

    Science.gov (United States)

    Ramos-Simões, Nuno A.; Granja-Martins, Fernando M.; Neto-Paixão, Helena M.; Jordán, Antonio; Zavala, Lorena M.

    2014-05-01

    1. INTRODUCTION Often, restoration of areas affected by fire faces lack of knowledge of how ecosystems respond to the action of fire. Depending on environmental conditions, structure and diversity of the vegetation or the severity of the fire, burnt systems can provide responses ranging from spontaneous recovery in a relatively short time to onset of severe degradation processes. For this reason, it is necessary to monitor the evolution of post-burned in the fire, in order to plan effective strategies for restoring systems and soil erosion control. In order to assess soil erosion risk, this research aims to is to analyse the evolution of vegetation cover in a Mediterranean burnt forest soil, using vegetation indexes derived from Landsat-7 (Thematic Mapper sensor-TM) and Landsat-8 (Operation Land Imager sensor, OLI). 2. METHODS This study was carried out in a forest area affected by a wildfire by 18-22 July 2012. The study area is located within the coordinates 37o 9' - 37o 21' N and 7o 40' - 7o 53' W, including part of the municipalities of Tavira and São Brás de Alportel (southern Portugal). The relief in the studied area has an irregular topography. Soils are shallow and develop mainly metamorphic rocks (as slates or quartzite) and igneous rocks, which produce acidic and nutrient-poor soils, poorly developed in depth. The wildfire was one of the most important fires in Portugal during the recent years, and affected more than 24000 ha. Vegetation is dominated by cork oak (Quercus suber) ,holm oaks (Quercus ilex), strawberry tree (Arbutus unedo) and sclerophyllous vegetation (mostly formed by Quercus coccifera and Rosmarinus officinalis). These species are adapted to acidic-poor soils and show a great capability of resprouting and germination after fire. The study area is poorly developed, with cork and timber harvesting and other forest products or tourism as main economic activities. The area shows a highly fragmented urban fabric with the sparse

  12. Life-cycle cost-benefit analysis of extensive vegetated roof systems.

    Science.gov (United States)

    Carter, Timothy; Keeler, Andrew

    2008-05-01

    The built environment has been a significant cause of environmental degradation in the previously undeveloped landscape. As public and private interest in restoring the environmental integrity of urban areas continues to increase, new construction practices are being developed that explicitly value beneficial environmental characteristics. The use of vegetation on a rooftop--commonly called a green roof--as an alternative to traditional roofing materials is an increasingly utilized example of such practices. The vegetation and growing media perform a number of functions that improve environmental performance, including: absorption of rainfall, reduction of roof temperatures, improvement in ambient air quality, and provision of urban habitat. A better accounting of the green roof's total costs and benefits to society and to the private sector will aid in the design of policy instruments and educational materials that affect individual decisions about green roof construction. This study uses data collected from an experimental green roof plot to develop a benefit cost analysis (BCA) for the life cycle of extensive (thin layer) green roof systems in an urban watershed. The results from this analysis are compared with a traditional roofing scenario. The net present value (NPV) of this type of green roof currently ranges from 10% to 14% more expensive than its conventional counterpart. A reduction of 20% in green roof construction cost would make the social NPV of the practice less than traditional roof NPV. Considering the positive social benefits and relatively novel nature of the practice, incentives encouraging the use of this practice in highly urbanized watersheds are strongly recommended.

  13. The impact of Pinus halepensis afforestation on Mediterranean spontaneous vegetation: do soil treatment and canopy cover matter?

    Institute of Scientific and Technical Information of China (English)

    Pasta Salvatore; Tommaso La Mantia; Juliane Rühl

    2012-01-01

    We investigated central Mediterranean Pinus halepensis plantations under semi-arid climate in order to evaluate the combined effect of soil treatment and afforestation practices on spontaneous plant species composition,richness and evenness,and on the trend and speed of vegetation dynamics.Phytosociological relevés of three different plot typologies,i.e.(1) soil-treatment and plantation,(2) only soil-treatment,(3) no soil-treatment and no plantation,were compared by (a) multivariate analysis and (b) with reference to species richness and evenness.Moreover,in order to compare vegetation dynamics within the plantations with those ones ongoing in semi-natural garrigue communities,we compared life form and syntaxonomic spectra between phytosociological relevés taken at 8 years of distance.DCA showed that floristic species composition and similarity are influenced by the canopy cover of Pine trees as well as by soil-treatment practices.Although species richness and evenness are not clearly related to neither soil treatment nor Pine afforestation,canopy cover clearly plays a major role:in fact,the highest Ph cover rates correspond to the lowest values of understory species richness.This is true also if only species of biogeographical/conservation interest are considered.Regarding vegetation dynamics,sites with dense Pine canopy cover evolve much slower than the adjacent garrigue communities.The same factors invoqued to explain the patterns of floristic composition and similarity (i.e.allelopathy and competition for light,water and nutrients) may also explain the lowering of diversity of therophytes and the strong decline of the cover perfomed by both therophytes and hemicryptophytes underneath the canopy of dense Ph plantations.Thus,in sites where Ph cover exceeds about 80%,thinning is recommended not only in order to accelerate succession,but also to give a natural 'shape' to afforestations.

  14. How well do we characterize the biophysical effects of vegetation cover change? Benchmarking land surface models against satellite observations.

    Science.gov (United States)

    Duveiller, Gregory; Forzieri, Giovanni; Robertson, Eddy; Georgievski, Goran; Li, Wei; Lawrence, Peter; Ciais, Philippe; Pongratz, Julia; Sitch, Stephen; Wiltshire, Andy; Arneth, Almut; Cescatti, Alessandro

    2017-04-01

    Changes in vegetation cover can affect the climate by altering the carbon, water and energy cycles. The main tools to characterize such land-climate interactions for both the past and future are land surface models (LSMs) that can be embedded in larger Earth System models (ESMs). While such models have long been used to characterize the biogeochemical effects of vegetation cover change, their capacity to model biophysical effects accurately across the globe remains unclear due to the complexity of the phenomena. The result of competing biophysical processes on the surface energy balance varies spatially and seasonally, and can lead to warming or cooling depending on the specific vegetation change and on the background climate (e.g. presence of snow or soil moisture). Here we present a global scale benchmarking exercise of four of the most commonly used LSMs (JULES, ORCHIDEE, JSBACH and CLM) against a dedicated dataset of satellite observations. To facilitate the understanding of the causes that lead to discrepancies between simulated and observed data, we focus on pure transitions amongst major plant functional types (PFTs): from different tree types (evergreen broadleaf trees, deciduous broadleaf trees and needleleaf trees) to either grasslands or crops. From the modelling perspective, this entails generating a separate simulation for each PFT in which all 1° by 1° grid cells are uniformly covered with that PFT, and then analysing the differences amongst them in terms of resulting biophysical variables (e.g net radiation, latent and sensible heat). From the satellite perspective, the effect of pure transitions is obtained by unmixing the signal of different 0.05° spatial resolution MODIS products (albedo, latent heat, upwelling longwave radiation) over a local moving window using PFT maps derived from the ESA Climate Change Initiative land cover map. After aggregating to a common spatial support, the observation and model-driven datasets are confronted and

  15. Estimating photosynthetic vegetation, non-photosynthetic vegetation and bare soil fractions using Landsat and MODIS data: Effects of site heterogeneity, soil properties and land cover

    Science.gov (United States)

    Guerschman, J. P.; Scarth, P.; McVicar, T.; Malthus, T. J.; Stewart, J.; Rickards, J.; Trevithick, R.; Renzullo, L. J.

    2013-12-01

    Vegetation fractional cover is a key indicator for land management monitoring, both in pastoral and agricultural settings. Maintaining adequate vegetation cover protects the soil from the effects of water and wind erosion and also ensures that carbon is returned to soil through decomposition. Monitoring vegetation fractional cover across large areas and continuously in time needs good remote sensing techniques underpinned by high quality ground data to calibrate and validate algorithms. In this study we used Landsat and MODIS reflectance data together with field measurements from 1476 observations across Australia to produce estimates of vegetation fractional cover using a linear unmixing technique. Specifically, we aimed at separating fractions of photosynthetic vegetation (PV), non-photosynthetic vegetation (NPV) and bare soil (B). We used Landsat reflectance averaged over a 3x3 pixel window representing the area actually measured on the ground and also a 'degraded' Landsat reflectance 40x40 pixel window to simulate the effect of a coarser sensor. Using these two Landsat reflectances we quantified the heterogeneity of each site. We used data from two MODIS-derived reflectance products: the Nadir BRDF-Adjusted surface Reflectance product (MCD43A4) and the MODIS 8-day surface reflectance (MOD09A1). We derived endmembers from the data and estimated fractional cover using a linear unmixing technique. Log transforms and band interaction terms were added to account for non-linearities in the spectral mixing. For each reflectance source we investigated if the residuals were correlated with site heterogeneity, soil colour, soil moisture and land cover type. As expected, the best model was obtained when Landsat data for a small region around each site was used. We obtained root mean square error (RMSE) values of 0.134, 0.175 and 0.153 for PV, NPV and B respectively. When we degraded the Landsat data to an area of ~1 km2 around each site the model performance decreased to

  16. Inter-Seasonal Dynamics of Vegetation Cover and Surface Temperature Distribution: a Case Study of Ondo State, Nigeria

    Science.gov (United States)

    Ibitolu, H. A.; Ogunjobi, K. O.

    2016-06-01

    This study employs Landsat ETM+ satellite imagery to access the inter-seasonal variations of Surface Temperature and Vegetation cover in Ondo State in 2013. Also, air temperature data for year 2013 acquired from 3 synoptic meteorological stations across the state were analyzed. The Single-channel Algorithm was used to extract the surface temperature maps from the digital number embedded within the individual pixel. To understand the spatio-temporal distribution of LST and vegetation across the various landuse types, 200 sample points were randomly chosen, so that each land-use covers 40 points. Imagery for the raining season where unavailable because of the intense cloud cover. Result showed that the lowest air temperature of 20.9°C was in January, while the highest air temperature of 34°C occurred in January and March. There was a significant shift in the vegetation greenness over Ondo State, as average NDVI tend to increase from a weak positive value (0.189) to a moderate value (0.419). The LULC map revealed that vegetation cover occupied the largest area (65%) followed by Built-up (26%), Swampy land (4%), Rock outcrop (3%) and water bodies (2%). The surface temperature maps revealed that January has the lowest temperature of 10°C experienced in the coastal riverine areas of Ilaje and Igbokoda, while the highest temperature of 39°C observed in September is experienced on the rocky grounds. The study also showed the existence of pockets of Urban Heat Islands (UHI) that are well scattered all over the state. This finding proves the capability and reliability of Satellite remote sensing for environmental studies.

  17. EnviroAtlas - Fresno, CA - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  18. EnviroAtlas - New Bedford, MA - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  19. EnviroAtlas - Phoenix, AZ - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  20. EnviroAtlas - Portland, OR - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  1. EnviroAtlas - Tampa, FL - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  2. EnviroAtlas - Durham, NC - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  3. EnviroAtlas - Portland, OR - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  4. EnviroAtlas - Fresno, CA - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  5. EnviroAtlas - Woodbine, IA - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  6. EnviroAtlas - Milwaukee, WI - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  7. EnviroAtlas - Tampa, FL - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  8. EnviroAtlas - Green Bay, WI - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  9. EnviroAtlas - Green Bay, WI - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  10. EnviroAtlas - Paterson, NJ - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  11. EnviroAtlas - Paterson, NJ - 51m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 51-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  12. EnviroAtlas - Pittsburgh, PA - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  13. 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.

  14. EnviroAtlas - Woodbine, IA - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  15. EnviroAtlas - Portland, ME - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  16. EnviroAtlas - Phoenix, AZ - 15m Riparian Buffer Vegetated Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset describes the percentage of a 15-m riparian buffer that is vegetated. There is a potential for decreased water quality in areas where the...

  17. Vegetation Cover Types of St. Vincent Island N.W.R.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The objectives of this vegetative study on St. Vincent National Wildlife Refuge were to: (1) identify and describe the major plant communities and associations on...

  18. Biomass increases go under cover: woody vegetation dynamics in South African rangelands

    CSIR Research Space (South Africa)

    Mograbi, PJ

    2015-05-01

    Full Text Available detection and ranging (LiDAR) to measure aboveground biomass and subcanopy structure, as an explanatory tool to unravel vegetation dynamics in structurally heterogeneous landscapes. We sampled three communal rangelands in Bushbuckridge, South Africa...

  19. DS 827, Vegetation Database for Land-Cover Mapping in Clark and Lincoln Counties, Nevada

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This geodatabase consists of a point feature class and related tables representing sample sites where vegetation data were collected from 2007 to 2013 in Clark and...

  20. Tree Plantation Will not Compensate Natural Woody Vegetation Cover Loss in the Atlantic Department of Southern Benin

    Directory of Open Access Journals (Sweden)

    Toyi, MS.

    2013-01-01

    Full Text Available This study deals with land use and land cover changes for a 33 years period. We assessed these changes for eight land cover classes in the south of Benin by using an integrated multi-temporal analysis using three Landsat images (1972 Landsat MSS, 1986 Landsat TM and 2005 Landsat ETM+. Three scenarios for the future were simulated using a first-order Markovian model based on annual probability matrices. The contribution of tree plantations to compensate forest loss was assessed. The results show a strong loss of forest and savanna, mainly due to increased agricultural land. Natural woody vegetation ("forest", "wooded savanna" and "tree and shrub savanna" will seriously decrease by 2025 due to the expansion of agricultural activities and the increase of settlements. Tree plantations are expected to double by 2025, but they will not compensate for the loss of natural woody vegetation cover. Consequently, we assist to a continuing woody vegetation area decrease. Policies regarding reforestation and forest conservation must be initiated to reverse the currently projected tendencies.

  1. DISTRIBUTION OF WOODY VEGETATION ON SODA WASTE DUMPS IN RELATION TO SPATIAL VARIATION IN SELECTED PARAMETERS OF THE MINERAL COVER

    Directory of Open Access Journals (Sweden)

    Ewelina Zając

    2016-11-01

    Full Text Available Development of woody plants in the course of succession on reclaimed soda waste dumps by use of mineral cover was analyzed. The spatial variation in the thickness and granulometric composition of the mineral cover was analysed by the Kriging method. The statistical measurements and geostatistical analysis were used to create maps showing areal variability for the parameters analysed. Analysis of the development of woody vegetation was based on field work and raster layers created on the basis of aerial photographs. No link was found between the parameters of the mineral cover and the distribution and development of spontaneous woody vegetation. The species composition in the study area is limited, and dominated by pioneer species, mainly the expansive black locust (Robinia pseudoacacia. Given that the soda waste disposal site is to be used as urban green spaces, the target ecosystem structure must be considered and a suitable course of action selected: further reclamation procedures improving substrate quality and enrichment of the species composition of the tree stand, or management involving sustaining the current state while controlling the course of natural succession of vegetation.

  2. Effects of seagulls on ecosystem respiration, soil nitrogen and vegetation cover on a pristine volcanic island, Surtsey, Iceland

    Science.gov (United States)

    Sigurdsson, B. D.; Magnusson, B.

    2010-03-01

    When Surtsey rose from the North Atlantic Ocean south of Iceland in 1963, it became a unique natural laboratory on how organisms colonize volcanic islands and form ecosystems with contrasting structures and functions. In July, 2004, ecosystem respiration rate (Re), soil properties and surface cover of vascular plants were measured in 21 permanent research plots distributed among the juvenile communities of the island. The plots were divided into two main groups, inside and outside a seagull (Larus spp.) colony established on the island. Vegetation cover of the plots was strongly related to the density of gull nests. Occurrence of nests and increased vegetation cover also coincided with significant increases in Re, soil carbon, nitrogen and C:N ratio, and with significant reductions in soil pH and soil temperatures. Temperature sensitivity (Q10 value) of Re was determined as 5.3. When compared at constant temperature the Re was found to be 59 times higher within the seagull colony, similar to the highest fluxes measured in drained wetlands or agricultural fields in Iceland. The amount of soil nitrogen, mainly brought onto the island by the seagulls, was the critical factor that most influenced ecosystem fluxes and vegetation development on Surtsey. The present study shows how ecosystem activity can be enhanced by colonization of animals that transfer resources from a nearby ecosystem.

  3. Effects of seagulls on ecosystem respiration, soil nitrogen and vegetation cover on a pristine volcanic island, Surtsey, Iceland

    Directory of Open Access Journals (Sweden)

    B. D. Sigurdsson

    2010-03-01

    Full Text Available When Surtsey rose from the North Atlantic Ocean south of Iceland in 1963, it became a unique natural laboratory on how organisms colonize volcanic islands and form ecosystems with contrasting structures and functions. In July, 2004, ecosystem respiration rate (Re, soil properties and surface cover of vascular plants were measured in 21 permanent research plots distributed among the juvenile communities of the island. The plots were divided into two main groups, inside and outside a seagull (Larus spp. colony established on the island. Vegetation cover of the plots was strongly related to the density of gull nests. Occurrence of nests and increased vegetation cover also coincided with significant increases in Re, soil carbon, nitrogen and C:N ratio, and with significant reductions in soil pH and soil temperatures. Temperature sensitivity (Q10 value of Re was determined as 5.3. When compared at constant temperature the Re was found to be 59 times higher within the seagull colony, similar to the highest fluxes measured in drained wetlands or agricultural fields in Iceland. The amount of soil nitrogen, mainly brought onto the island by the seagulls, was the critical factor that most influenced ecosystem fluxes and vegetation development on Surtsey. The present study shows how ecosystem activity can be enhanced by colonization of animals that transfer resources from a nearby ecosystem.

  4. Adapting Extension Food Safety Programming for Vegetable Growers to Accommodate Differences in Ethnicity, Farming Scale, and Other Individual Factors

    Science.gov (United States)

    Kline, Terence R.; Kneen, Harold; Barrett, Eric; Kleinschmidt, Andy; Doohan, Doug

    2012-01-01

    Differences in vegetable production methods utilized by American growers create distinct challenges for Extension personnel providing food safety training to producer groups. A program employing computers and projectors will not be accepted by an Amish group that does not accept modern technology. We have developed an outreach program that covers…

  5. Adapting Extension Food Safety Programming for Vegetable Growers to Accommodate Differences in Ethnicity, Farming Scale, and Other Individual Factors

    Science.gov (United States)

    Kline, Terence R.; Kneen, Harold; Barrett, Eric; Kleinschmidt, Andy; Doohan, Doug

    2012-01-01

    Differences in vegetable production methods utilized by American growers create distinct challenges for Extension personnel providing food safety training to producer groups. A program employing computers and projectors will not be accepted by an Amish group that does not accept modern technology. We have developed an outreach program that covers…

  6. 78 FR 44922 - Vegetable and Specialty Crop Marketing Orders; Notice of Request for Extension and Revision of a...

    Science.gov (United States)

    2013-07-25

    ... Agricultural Marketing Service Vegetable and Specialty Crop Marketing Orders; Notice of Request for Extension and Revision of a Currently Approved Information Collection AGENCY: Agricultural Marketing Service... of 1995 (44 U.S.C. Chapter 35), this notice announces the Agricultural Marketing Service's...

  7. Stimulation of methane oxidation potential and effects on vegetation growth by bottom ash addition in a landfill final evapotranspiration cover.

    Science.gov (United States)

    Kim, Gil Won; Ho, Adrian; Kim, Pil Joo; Kim, Sang Yoon

    2016-09-01

    The landfilling of municipal solid waste is a significant source of atmospheric methane (CH4), contributing up to 20% of total anthropogenic CH4 emissions. The evapotranspiration (ET) cover system, an alternative final cover system in waste landfills, has been considered to be a promising way to mitigate CH4 emissions, as well as to prevent water infiltration using vegetation on landfill cover soils. In our previous studies, bottom ash from coal-fired power plants was selected among several industrial residues (blast furnace slag, bottom ash, construction waste, steel manufacture slag, stone powder sludge, and waste gypsum) as the best additive for ET cover systems, with the highest mechanical performance achieved for a 35% (wtwt(-1)) bottom ash content in soil. In this study, to evaluate the field applicability of bottom ash mixed soil as ET cover, four sets of lysimeters (height 1.2m×width 2m×length 6m) were constructed in 2007, and four different treatments were installed: (i) soil+bottom ash (35% wtwt(-1)) (SB); (ii) soil+compost (2% wtwt(-1), approximately corresponding to 40Mgha(-1) in arable field scale) (SC); (iii) soil+bottom ash+compost (SBC); and (iv) soil only as the control (S). The effects of bottom ash mixing in ET cover soil on CH4 oxidation potential and vegetation growth were evaluated in a pilot ET cover system in the 5th year after installation by pilot experiments using the treatments. Our results showed that soil properties were significantly improved by bottom ash mixing, resulting in higher plant growth. Bottom ash addition significantly increased the CH4 oxidation potential of the ET cover soil, mainly due to improved organic matter and available copper concentration, enhancing methanotrophic abundances in soil amended with bottom ash. Conclusively, bottom ash could be a good alternative as a soil additive in the ET cover system to improve vegetation growth and mitigate CH4 emission impact in the waste landfill system. Copyright © 2016

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-15

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

  9. 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.

  10. 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.

  11. Evidence for an extensive Phanerozoic sediment cover on the Canadian and Fenno-Scandian shields

    Energy Technology Data Exchange (ETDEWEB)

    Laine, E.P.; Dickson, S.M.

    1985-01-01

    Examination of the age and diameter of 75 terrestrial meteorite impact craters taken from platform and shield regions throughout the world suggest that both the Canadian and Fenno-Scandian Shields were covered by a sedimentary blanket during a portion of the Phanerozoic. Subsequent erosion, fostered perhaps by a combination of glacial and tectonic processes, has exposed both of these shields to reveal an anomalous distribution of craters through time. The primary evidence for sedimentary cover and subsequent erosion is in the form of a 280 Myr gap in the record of craters less than 15 km in diameter. Small craters of Cambrian, Ordovician and Silurian age are found in shield regions, suggesting either a thin or non-existent sediment cover during this period. However, there is no record of small diameter craters on either shield of Devonian, Carboniferous, Permian, Triassic, or Jurassic age (400 to 120 Myr). This 280 Myr gap suggests that the shields were protected from smaller body impacts by a sedimentary cover. In contrast, the record of impacts on platform sediments implies no such hiatus in the infall of cosmic bodies to the earth's surface between the Devonian and the Early Cretaceous. Subsequent erosion, perhaps by Early Cretaceous time, exposed the shields to further bombardment. In addition, pre-Devonian craters became exhumed. Thus, the record of impact craters suggests that the Canadian and Fenno-Scandian Shields were covered by sediments while part of Pangaea.

  12. Comparison Between Fractional Vegetation Cover Retrievals from Vegetation Indices and Spectral Mixture Analysis: Case Study of PROBA/CHRIS Data Over an Agricultural Area

    Directory of Open Access Journals (Sweden)

    Pablo Martinez

    2009-02-01

    Full Text Available In this paper we compare two different methodologies for Fractional Vegetation Cover (FVC retrieval from Compact High Resolution Imaging Spectrometer (CHRIS data onboard the European Space Agency (ESA Project for On-Board Autonomy (PROBA platform. The first methodology is based on empirical approaches using Vegetation Indices (VIs, in particular the Normalized Difference Vegetation Index (NDVI and the Variable Atmospherically Resistant Index (VARI. The second methodology is based on the Spectral Mixture Analysis (SMA technique, in which a Linear Spectral Unmixing model has been considered in order to retrieve the abundance of the different constituent materials within pixel elements, called Endmembers (EMs. These EMs were extracted from the image using three different methods: i manual extraction using a land cover map, ii Pixel Purity Index (PPI and iii Automated Morphological Endmember Extraction (AMEE. The different methodologies for FVC retrieval were applied to one PROBA/CHRIS image acquired over an agricultural area in Spain, and they were calibrated and tested against in situ measurements of FVC estimated with hemispherical photographs. The results obtained from VIs show that VARI correlates better with FVC than NDVI does, with standard errors of estimation of less than 8% in the case of VARI and less than 13% in the case of NDVI when calibrated using the in situ measurements. The results obtained from the SMA-LSU technique show Root Mean Square Errors (RMSE below 12% when EMs are extracted from the AMEE method and around 9% when extracted from the PPI method. A RMSE value below 9% was obtained for manual extraction of EMs using a land cover use map.

  13. Human Activity Influences on Vegetation Cover Changes in Beijing, China, from 2000 to 2015

    Directory of Open Access Journals (Sweden)

    Meichen Jiang

    2017-03-01

    Full Text Available For centuries, the rapid development of human society has already made human activity the dominant factor in the terrestrial ecosystem. As the city of greatest importance in China, the capital Beijing has experienced eco-environmental changes with unprecedented economic and population growth during the past few decades. To better understand the ecological transition and its correlations in Beijing, Landsat Thematic Mapper (TM and Operational Land Imager (OLI images were used to investigate vegetation coverage changes using a dimidiate pixel model. Piecewise linear regression, bivariate-partial correlation analysis, and factor analysis were applied to the probing of the relationship between vegetation coverage changes and climatic/human-induced factors. The results showed that from 2000 to 2005, 2005 to 2010, and 2010 to 2015, Beijing experienced both restoration (6.33%, 10.08%, and 12.81%, respectively and degradation (13.62%, 9.35%, and 9.49%, respectively. The correlation analysis results between climate and vegetation changes demonstrated that from 2000 to 2015, both the multi-year annual mean temperature (r = −0.819, p < 0.01 and the multi-year annual mean precipitation (r = 0.653, p < 0.05 had a significantly correlated relationship with vegetation change. The Beijing-Tianjin Sandstorm Source Control Project (BTSSCP has shown beneficial spatial effects on vegetation restoration; the total effectiveness in conservation areas (84.94 in 2000–2010 was much better than non-BTSSCP areas (34.34 in 2000–2010. The most contributory socioeconomic factors were the population (contribution = 54.356% and gross domestic product (GDP (contribution = 30.677%. The population showed a significantly negative correlation with the overall vegetation coverage (r = −0.684, p < 0.05. The GDP was significantly negatively correlated with vegetation in Tongzhou, Daxing, Central city, Fangshan, Shunyi, and Changping (r = −0.601, p < 0.01, while positively

  14. 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.

  15. Detecting land-cover change using mappable vegetation related indices: A case study from Sinharaja Man and the Biosphere Reserve

    Directory of Open Access Journals (Sweden)

    BD Madurapperuma

    2014-06-01

    Full Text Available This study evaluates multi-year changes of vegetation in the Sinharaja Man and the Biosphere (MAB reserve using mappable vegetation related indices viz., Normalized Difference Vegetation Index (NDVI and Burn Index (BI. Land-cover changes in the Sinharaja MAB reserve were detected using Landsat 7 ETM+ images for 1993, 2001, and 2005. Seven individual bands of each image were converted to new multiband files by layer stacking using ENVI® 4.5. Then the multiband files were re-projected to UTM Zone 44 North, WGS-84 Datum. Each data set was exported to ENVI® EX software package to detect the changes between time steps based on NDVI and BI using an image difference tool. Land-cover data, which were obtained from the DIVA GIS web portal, were compared with Landsat image data. Results of BI showed that the Sinharaja MAB reserve fringe was vulnerable to forest fire. For example, from 1993- 2001, 160 ha identified as burned area. In contrast, from 2001-2005, 79 ha burned, and for the entire period of 1993-2005, 10 ha burned. NDVI resulted in a 962 ha increase of vegetation prime at the western Sinharaja from 2001-2005. In addition, there was a 15 ha decrease in vegetation from 1993-2005. The results were visualized using an embedded 3D render window of Google Earth and 2D view of ArcGIS explorer online. In conclusion, in-situ ground truthing data is needed for the fire-influenced area for implementing sustainable forest resource management at the Sinharaja MAB reserve. Normal 0 false false false EN-GB X-NONE X-NONE

  16. 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.

  17. A Proposed Extension to the Soil Moisture and Ocean Salinity Level 2 Algorithm for Mixed Forest and Moderate Vegetation Pixels

    Science.gov (United States)

    Panciera, Rocco; Walker, Jeffrey P.; Kalma, Jetse; Kim, Edward

    2011-01-01

    The Soil Moisture and Ocean Salinity (SMOS)mission, launched in November 2009, provides global maps of soil moisture and ocean salinity by measuring the L-band (1.4 GHz) emission of the Earth's surface with a spatial resolution of 40-50 km.Uncertainty in the retrieval of soilmoisture over large heterogeneous areas such as SMOS pixels is expected, due to the non-linearity of the relationship between soil moisture and the microwave emission. The current baseline soilmoisture retrieval algorithm adopted by SMOS and implemented in the SMOS Level 2 (SMOS L2) processor partially accounts for the sub-pixel heterogeneity of the land surface, by modelling the individual contributions of different pixel fractions to the overall pixel emission. This retrieval approach is tested in this study using airborne L-band data over an area the size of a SMOS pixel characterised by a mix Eucalypt forest and moderate vegetation types (grassland and crops),with the objective of assessing its ability to correct for the soil moisture retrieval error induced by the land surface heterogeneity. A preliminary analysis using a traditional uniform pixel retrieval approach shows that the sub-pixel heterogeneity of land cover type causes significant errors in soil moisture retrieval (7.7%v/v RMSE, 2%v/v bias) in pixels characterised by a significant amount of forest (40-60%). Although the retrieval approach adopted by SMOS partially reduces this error, it is affected by errors beyond the SMOS target accuracy, presenting in particular a strong dry bias when a fraction of the pixel is occupied by forest (4.1%v/v RMSE,-3.1%v/v bias). An extension to the SMOS approach is proposed that accounts for the heterogeneity of vegetation optical depth within the SMOS pixel. The proposed approach is shown to significantly reduce the error in retrieved soil moisture (2.8%v/v RMSE, -0.3%v/v bias) in pixels characterised by a critical amount of forest (40-60%), at the limited cost of only a crude estimate of the

  18. The influence of vegetation covers on soil moisture dynamics at high temporal resolution in scattered tree woodlands of Mediterranean climate

    Science.gov (United States)

    Lozano-Parra, Javier; Schnabel, Susanne; Ceballos-Barbancho, Antonio

    2015-04-01

    Soil water is a key factor that controls the organization and functioning of dryland ecosystems. However, in spite of its great importance in ecohydrological processes, most of the studies focus on daily or longer timescales, while its dynamics at shorter timescales are very little known. The main objective of this work was to determine the role of vegetation covers (grassland and tree canopy) in the soil hydrological response using measurements with high temporal resolution in evergreen oak woodland with Mediterranean climate. For this, soil water content was monitored continuously with a temporal resolution of 30 minutes and by means of capacitance sensors, mainly for the hydrological years 2010-2011 and 2011-2012. They were installed at 5, 10 and 15 cm, and 5 cm above the bedrock and depending on soil profile. This distribution along the soil profile is justified because soils are generally very shallow and most of the roots are concentrated in the upper layer. The sensors were gathered in 8 soil moisture stations in two contrasting situations characterized by different vegetation covers: under tree canopy and in open spaces or grasslands. Soil moisture variations were calculated at rainfall event scale at top soil layer and deepest depth by the difference between the final and initial soil moisture registered by a sensor at the finish and the beginning of the rainfall event, respectively. Besides, as soil moisture changes are strongly influenced by antecedent conditions, different antecedent soil moisture conditions or states, from driest to wettest, were also defined. The works were carried out in 3 experimental farms of the Spanish region of Extremadura. Results obtained revealed that rainwater amount bypassing vegetation covers and reaching the soil may temporarily be modified by covers according to precipitation properties and antecedent environmental conditions (from dry to wet) before the rain episode. Rainfall amounts triggering a positive soil

  19. 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.

  20. Comparing Different Approaches for Mapping Urban Vegetation Cover from Landsat ETM+ Data: A Case Study on Brussels

    Directory of Open Access Journals (Sweden)

    Frank Canters

    2008-06-01

    Full Text Available Urban growth and its related environmental problems call for sustainable urban management policies to safeguard the quality of urban environments. Vegetation plays an important part in this as it provides ecological, social, health and economic benefits to a city’s inhabitants. Remotely sensed data are of great value to monitor urban green and despite the clear advantages of contemporary high resolution images, the benefits of medium resolution data should not be discarded. The objective of this research was to estimate fractional vegetation cover from a Landsat ETM+ image with sub-pixel classification, and to compare accuracies obtained with multiple stepwise regression analysis, linear spectral unmixing and multi-layer perceptrons (MLP at the level of meaningful urban spatial entities. Despite the small, but nevertheless statistically significant differences at pixel level between the alternative approaches, the spatial pattern of vegetation cover and estimation errors is clearly distinctive at neighbourhood level. At this spatially aggregated level, a simple regression model appears to attain sufficient accuracy. For mapping at a spatially more detailed level, the MLP seems to be the most appropriate choice. Brightness normalisation only appeared to affect the linear models, especially the linear spectral unmixing.

  1. Comparing Different Approaches for Mapping Urban Vegetation Cover from Landsat ETM+ Data: A Case Study on Brussels.

    Science.gov (United States)

    Van de Voorde, Tim; Vlaeminck, Jeroen; Canters, Frank

    2008-06-10

    Urban growth and its related environmental problems call for sustainable urban management policies to safeguard the quality of urban environments. Vegetation plays an important part in this as it provides ecological, social, health and economic benefits to a city's inhabitants. Remotely sensed data are of great value to monitor urban green and despite the clear advantages of contemporary high resolution images, the benefits of medium resolution data should not be discarded. The objective of this research was to estimate fractional vegetation cover from a Landsat ETM+ image with sub-pixel classification, and to compare accuracies obtained with multiple stepwise regression analysis, linear spectral unmixing and multi-layer perceptrons (MLP) at the level of meaningful urban spatial entities. Despite the small, but nevertheless statistically significant differences at pixel level between the alternative approaches, the spatial pattern of vegetation cover and estimation errors is clearly distinctive at neighbourhood level. At this spatially aggregated level, a simple regression model appears to attain sufficient accuracy. For mapping at a spatially more detailed level, the MLP seems to be the most appropriate choice. Brightness normalisation only appeared to affect the linear models, especially the linear spectral unmixing.

  2. Vegetation Cover Change in Yellowstone National Park Detected Using Landsat Satellite Image Analysis

    Science.gov (United States)

    Potter, Christopher S.

    2015-01-01

    Results from Landsat satellite image analysis since 1987 in all unburned areas (since the 1880s) of Yellowstone National Park (YNP) showed that consistent decreases in the normalized difference vegetation index (NDVI) have been strongly dependent on periodic variations in peak annual snow water equivalents (SWE).

  3. Multiple support vector machines for land cover change detection: An application for mapping urban extensions

    Science.gov (United States)

    Nemmour, Hassiba; Chibani, Youcef

    The reliability of support vector machines for classifying hyper-spectral images of remote sensing has been proven in various studies. In this paper, we investigate their applicability for land cover change detection. First, SVM-based change detection is presented and performed for mapping urban growth in the Algerian capital. Different performance indicators, as well as a comparison with artificial neural networks, are used to support our experimental analysis. In a second step, a combination framework is proposed to improve change detection accuracy. Two combination rules, namely, Fuzzy Integral and Attractor Dynamics, are implemented and evaluated with respect to individual SVMs. Recognition rates achieved by individual SVMs, compared to neural networks, confirm their efficiency for land cover change detection. Furthermore, the relevance of SVM combination is highlighted.

  4. Biomass Increases Go under Cover: Woody Vegetation Dynamics in South African Rangelands.

    Directory of Open Access Journals (Sweden)

    Penelope J Mograbi

    Full Text Available Woody biomass dynamics are an expression of ecosystem function, yet biomass estimates do not provide information on the spatial distribution of woody vegetation within the vertical vegetation subcanopy. We demonstrate the ability of airborne light detection and ranging (LiDAR to measure aboveground biomass and subcanopy structure, as an explanatory tool to unravel vegetation dynamics in structurally heterogeneous landscapes. We sampled three communal rangelands in Bushbuckridge, South Africa, utilised by rural communities for fuelwood harvesting. Woody biomass estimates ranged between 9 Mg ha(-1 on gabbro geology sites to 27 Mg ha(-1 on granitic geology sites. Despite predictions of woodland depletion due to unsustainable fuelwood extraction in previous studies, biomass in all the communal rangelands increased between 2008 and 2012. Annual biomass productivity estimates (10-14% p.a. were higher than previous estimates of 4% and likely a significant contributor to the previous underestimations of modelled biomass supply. We show that biomass increases are attributable to growth of vegetation <5 m in height, and that, in the high wood extraction rangeland, 79% of the changes in the vertical vegetation subcanopy are gains in the 1-3 m height class. The higher the wood extraction pressure on the rangelands, the greater the biomass increases in the low height classes within the subcanopy, likely a strong resprouting response to intensive harvesting. Yet, fuelwood shortages are still occurring, as evidenced by the losses in the tall tree height class in the high extraction rangeland. Loss of large trees and gain in subcanopy shrubs could result in a structurally simple landscape with reduced functional capacity. This research demonstrates that intensive harvesting can, paradoxically, increase biomass and this has implications for the sustainability of ecosystem service provision. The structural implications of biomass increases in communal rangelands

  5. Analyses of changes in vegetation cover in the South and Sub-Taiga of Western Siberia using Landsat data

    Science.gov (United States)

    Dyukarev, Egor; Pologova, Nina; Golovatskaya, Eugenia

    2010-05-01

    Understanding human impact on vegetation composition and structure, at scales from the patch to the globe, and capacity to monitor change over time is fundamental research problem to address Global Change and ensure sustainable development. Natural ecosystems at the South and Sob-Taiga zone of Western Siberia are characterized by development of an early successional states, given the projected increase in disturbance, or will be converted into human-dominated terrestrial production systems. Disturbances (e.g., fire, dieback due to insect attacks) appear to be increasing in some regions, leading to fragmentation of natural ecosystems and to a generally "weedier," structurally simpler biosphere with fewer systems in a more ecologically complex old-growth state. The analysis of structure of vegetation cover at two test sites located at the south-west part of the West-Siberian Plain in the South and Sub-Taiga zone was made using LANDSAT space images and ground data. The studied area of the first test site ("Bakchar") is occupied by bogs, paludificated forests and cultivated lands. Test site "Tomsk" covered by cultivated lands in the south, dark coniferous forest complexes an early and old-growth state in the north part. Mire types at the test sites are presented by open fens, ridge-hollow / ridge-lake complexes and pine-shrub-sphagnum communities with different tree height and layer density. During the XX century the vegetation cover was exposed to natural and anthropogenic changes. Comparison of space images from different years (1990, 1999 and 2007) allowed revealing dynamics in vegetation cover. Forest change was calculated using the Disturbance Index (Healey, 2006). Decrease of forest area in 1990-1999 are primary occurs due to intense forest cutting for timber industry and local use. A strong wind have damaged forests between 1990 and 1999 in stripes oriented from south-west to north -east in the prevailing wind direction. Strong winds were registered in 2003

  6. Assessing Vegetation Cover Dynamics Induced by Policy-Driven Ecological Restoration and Implication to Soil Erosion in Southern China.

    Science.gov (United States)

    Zhang, Jien; Wang, Tianming; Ge, Jianping

    2015-01-01

    In the aftermath of the severe droughts and floods at the end of the 20th century, the Chinese government launched several ecological restoration projects, including the Natural Forest Protection Program in 1998 and the Grain-for-Green Program in 1999, to promote afforestation and reforestation to reduce surface runoff and consequent soil erosion nationwide. However, it is still unclear how vegetation has changed in southern China since the launch of these programs. In this study, we used the MODIS Enhanced Vegetation Index (EVI) to analyze the vegetation cover dynamics in southern China from 2000 to 2009 and evaluate the resulting effects of controlling soil erosion. Our observations indicate that 5.3% of the study area significantly increased and 0.98% significantly decreased in EVI value (p soil erosion based upon monitoring sediment yields at hydrologic stations in the Yangtze River. This study displays the spatial patterns of trend in vegetation growth since the beginning of the 21st century in southern China and highlights the important role of China's afforestation program.

  7. Land Use and Land Cover Change, and Woody Vegetation Diversity in Human Driven Landscape of Gilgel Tekeze Catchment, Northern Ethiopia

    Directory of Open Access Journals (Sweden)

    Samuale Tesfaye

    2014-01-01

    Full Text Available Land use and land cover (LULC change through inappropriate agricultural practices and high human and livestock population pressure have led to severe land degradation in the Ethiopian highlands. This has led to further degradation such as biodiversity loss, deforestation, and soil erosion. The study examined woody vegetation diversity status and the impact of drivers of change across different LULC types and agroecological zones in Gilgel Tekeze catchment, northern Ethiopian highlands. LULC dynamics were assessed using GIS techniques on 1976, 1986, and 2008 satellite images. Vegetation data were collected from 135 sample plots (20 m × 20 m from five LULC types, namely, forest, shrub-bush, grazing, settlement, and cultivated land, in the three agroecological zones; Kolla, Weyna-Dega, and Dega. Differences in vegetation structure and composition and their relationship to agroecological zones were tested using two-way ANOVA and PCA technique. The results show that vegetation structure and composition significantly differed across all LULC types in different agroecological zones particularly in sapling density, tree height, and shrub height and in each agroecological zone between forest land, shrub-bush land, and settlement area. Overall, Weyna-Dega agroecological zone and the shrub-bush land had more structural and compositional diversity than the other agroecological zones and LULC types.

  8. [Effects of climate and grazing on the vegetation cover change in Xilinguole League of Inner Mongolia, North China].

    Science.gov (United States)

    Wang, Hai-Mei; Li, Zheng-Hai; Wang, Zhen

    2013-01-01

    Based on the monthly temperature and precipitation data of 15 meteorological stations and the statistical data of livestock density in Xilinguole League in 1981-2007, and by using ArcGIS, this paper analyzed the spatial distribution of the climate aridity and livestock density in the League, and in combining with the ten-day data of the normalized difference vegetation index (NDVI) in 1981-2007, the driving factors of the vegetation cover change in the League were discussed. In the study period, there was a satisfactory linear regression relationship between the climate aridity and the vegetation coverage. The NDVI and the livestock density had a favorable binomial regression relationship. With the increase of NDVI, the livestock density increased first and decreased then. The vegetation coverage had a complex linear relationship with livestock density and climate aridity. The NDVI had a positive correlation with climate aridity, but a negative correlation with livestock density. Compared with livestock density, climate aridity had far greater effects on the NDVI.

  9. 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...

  10. Mineralization of organic phosphorus in soil size fractions under different vegetation covers in the north of Rio de Janeiro

    Directory of Open Access Journals (Sweden)

    Joice Cleide de Oliveira Rita

    2013-10-01

    Full Text Available In unfertilized, highly weathered tropical soils, phosphorus (P availability to plants is dependent on the mineralization of organic P (Po compounds. The objective of this study was to estimate the mineralization of total and labile Po in soil size fractions of > 2.0, 2.0-0.25 and 2.0 and 2.0-0.25 mm fractions, respectively. In contrast, there was an average increase of 90 % of total Po in microaggregates of 2.0 (-50 % and < 0.25 mm (-76 % fractions, but labile Po increased by 35 % in the 2.0-0.25 mm fraction. The Po fraction relative to total extracted P and total labile P within the soil size fractions varied with the vegetation cover and incubation time. Therefore, the distribution of P fractions (Pi and Po in the soil size fraction revealed the distinctive ability of the cover species to recycle soil P. Consequently, the potential of Po mineralization varied with the size fraction and vegetation cover. Because Po accounted for most of the total labile P, the P availability to plants was closely related to the mineralization of this P fraction.

  11. The impact of the provision of water for game on the basal cover of the herbaceous vegetation around a dam in the Kruger National Park

    Directory of Open Access Journals (Sweden)

    I. Thrash

    1991-09-01

    Full Text Available A line intercept survey was done on the herbaceous vegetation in permanently marked plots at distance intervals from the Wik-en-Weeg Dam, Kruger National Park, in 1973. The survey was repeated in 1990 so that changes in basal cover could be determined in relation to distance from the dam. Positive relationships with distance from the dam were found for the relative total percentage basal cover of the herbaceous vegetation, as well as for the relative basal cover of, respectively, grasses, forbs, decreasers and increasers. It was concluded that the provision of a permanent supply of drinking water for game in the Wik-en-Weeg Dam has had an impact on the nearby herbaceous community basal cover composition, as well as a negative impact on the basal cover of the herbaceous vegetation in the vicinity. The basal cover of the herbaceous stratum was more sensitive to the effect of the dam than parameters of the woody stratum.

  12. Biomass Increases Go under Cover: Woody Vegetation Dynamics in South African Rangelands

    Science.gov (United States)

    Mograbi, Penelope J.; Knapp, David E.; Martin, Roberta E.; Main, Russell

    2015-01-01

    Woody biomass dynamics are an expression of ecosystem function, yet biomass estimates do not provide information on the spatial distribution of woody vegetation within the vertical vegetation subcanopy. We demonstrate the ability of airborne light detection and ranging (LiDAR) to measure aboveground biomass and subcanopy structure, as an explanatory tool to unravel vegetation dynamics in structurally heterogeneous landscapes. We sampled three communal rangelands in Bushbuckridge, South Africa, utilised by rural communities for fuelwood harvesting. Woody biomass estimates ranged between 9 Mg ha-1 on gabbro geology sites to 27 Mg ha-1 on granitic geology sites. Despite predictions of woodland depletion due to unsustainable fuelwood extraction in previous studies, biomass in all the communal rangelands increased between 2008 and 2012. Annual biomass productivity estimates (10–14% p.a.) were higher than previous estimates of 4% and likely a significant contributor to the previous underestimations of modelled biomass supply. We show that biomass increases are attributable to growth of vegetation biomass increases in the low height classes within the subcanopy, likely a strong resprouting response to intensive harvesting. Yet, fuelwood shortages are still occurring, as evidenced by the losses in the tall tree height class in the high extraction rangeland. Loss of large trees and gain in subcanopy shrubs could result in a structurally simple landscape with reduced functional capacity. This research demonstrates that intensive harvesting can, paradoxically, increase biomass and this has implications for the sustainability of ecosystem service provision. The structural implications of biomass increases in communal rangelands could be misinterpreted as woodland recovery in the absence of three-dimensional, subcanopy information. PMID:25969985

  13. Low-cost computer classification of land cover in the Portland area, Oregon, by signature extension techniques

    Science.gov (United States)

    Gaydos, Leonard

    1978-01-01

    Computer-aided techniques for interpreting multispectral data acquired by Landsat offer economies in the mapping of land cover. Even so, the actual establishment of the statistical classes, or "signatures," is one of the relatively more costly operations involved. Analysts have therefore been seeking cost-saving signature extension techniques that would accept training data acquired for one time or place and apply them to another. Opportunities to extend signatures occur in preprocessing steps and in the classification steps that follow. In the present example, land cover classes were derived by the simplest and most direct form of signature extension: Classes statistically derived from a Landsat scene for the Puget Sound area, Wash., were applied to the Portland area, Oreg., using data for the next Landsat scene acquired less than 25 seconds down orbit. Many features can be recognized on the reduced-scale version of the Portland land cover map shown in this report, although no statistical assessment of its accuracy is available.

  14. 5 CFR 894.603 - Is there an extension of coverage and right to convert when my coverage stops or when a covered...

    Science.gov (United States)

    2010-01-01

    ... right to convert when my coverage stops or when a covered family member loses eligibility? 894.603... Coverage § 894.603 Is there an extension of coverage and right to convert when my coverage stops or when a covered family member loses eligibility? No. There is no extension of coverage or right to convert to...

  15. 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

  16. Moisture content behaviour in extensive green roofs during dry periods: the influence of vegetation and substrate characteristics

    OpenAIRE

    Berretta, C; Poe, S.; Stovin, V.

    2014-01-01

    Evapotranspiration (ET) is a key parameter that influences the stormwater retention capacity, and thus the hydrological performance, of green roofs. This paper investigates how the moisture content in extensive green roofs varies during dry periods due to evapotranspiration. The study is supported by 29 months continuous field monitoring of the moisture content within four green roof test beds. The beds incorporated three different substrates, with three being vegetated with sedum and one lef...

  17. Analysis of the Scaling Effects in the Area-Averaged Fraction of Vegetation Cover Retrieved Using an NDVI-Isoline-Based Linear Mixture Model

    OpenAIRE

    Hiroki Yoshioka; Kenta Obata; Tomoaki Miura

    2012-01-01

    The spectral unmixing of a linear mixture model (LMM) with Normalized Difference Vegetation Index (NDVI) constraints was performed to estimate the fraction of vegetation cover (FVC) over the earth’s surface in an effort to facilitate long-term surface vegetation monitoring using a set of environmental satellites. Although the integrated use of multiple sensors improves the spatial and temporal quality of the data sets, area-averaged FVC values obtained using an LMM-based algorithm suffer from...

  18. Inter-Algorithm Relationships for the Estimation of the Fraction of Vegetation Cover Based on a Two Endmember Linear Mixture Model with the VI Constraint

    OpenAIRE

    Kenta Obata; Hiroki Yoshioka

    2010-01-01

    Measurements of the fraction of vegetation cover (FVC), retrieved from remotely sensed reflectance spectra, serves as a useful measure of land cover changes on the regional and global scales. A linear mixture model (LMM) is frequently employed to analytically estimate the FVC using the spectral vegetation index (VI) as a constraint. Variations in the application of this algorithm arise due to differences in the choice of endmember spectra and VI model assumptions. As a result, the retrieved F...

  19. The effects of vegetation cover on soil nematode communities in various biotopes disturbed by industrial emissions.

    Science.gov (United States)

    Šalamún, Peter; Hanzelová, Vladimíra; Miklisová, Dana; Šestinová, Oľga; Findoráková, Lenka; Kováčik, Peter

    2017-08-15

    Better understanding of interactions among belowground and aboveground components in biotopes may improve our knowledge about soil ecosystem, and is necessary in environment assessment using indigenous soil organisms. In this study, we proposed that in disturbed biotopes, vegetation play important role in the buffering of contamination impact on soil communities and decrease the ecological pressure on soil biota. To assess the effects of these interactions we compared nematode communities, known for their bioindication abilities, from four types of disturbed and undisturbed biotopes (coniferous forest, permanent grassland, agricultural field, clearings), where the main stress agent was represented by long-term acidic industrial emissions containing heavy metals (As, Cd, Cu, and Pb). To understand the ecological interactions taking place in studied biotopes, we studied abiotic factors (soil properties) and biotic factors (vegetation, nematode communities). Except significant increase in metals total and mobile concentrations in disturbed biotopes soil, we found acidification of soil horizon, mainly in the clearings (pH=3.68), due to SO2 precipitation. These factors has caused in clearings degradation of native phytocoenoses and decrease in decomposition rate characterized by high amount of organic matter (Cox=4.29%). Nematodes reacts to these conditions by shifts in trophic structure (bacteriovores to fungal feeders), increase in c-p 2 genera (Aphelenchoides, Acrobeloides, and Cephalobus), absence of sensitive groups (c-p 3-5, omnivores, predators), and decrease in ecological indices (SI, MI, MI2-5, H'). Similar contamination was found in forest biotope, but the nematodes composition indicates more suitable conditions; more complex community structure (presence of sensitive trophic and higher c-p groups), higher abundance and indices values, comparable with less stressed field and grassland biotopes. As showed our results, the vegetation undoubtedly plays an

  20. Increasing the accuracy and automation of fractional vegetation cover estimation from digital photographs

    Science.gov (United States)

    The use of automated methods to estimate canopy cover (CC) from digital photographs has increased in recent years given its potential to produce accurate, fast and inexpensive CC measurements. Wide acceptance has been delayed because of the limitations of these methods. This work introduces a novel ...

  1. The comparison analysis of land cover change based on vegetation index and multispectral classification (Case study Leihitu Peninsula Ambon City District

    Directory of Open Access Journals (Sweden)

    W.A. Siahaya

    2015-07-01

    Full Text Available The study utilizes Landsat-7 ETM+ 2001and Landsat TM5 2009 based on Normalized Differences Vegetation Index (NDVI and 457 colour composite at the study area located in Leihitu Peninsula, Ambon City District, Ambon Island, Moluccas Province. The classified satellite data under NDVI and 457 colour composite of 2001 and 2009 of 2001 and 2009 were used to determine land cover change that have occurred in the study areas. This study attempts to use a comparative change detection analysis in land cover that has occurred in the study area with NDVI and 457 colour composite over 9 year period (2001 to 2009. The results of the present study disclose that total area increased their land cover were bare land and impermeable surface, herbaceous and shrubs, low density vegetation, and medium density vegetation, while high density vegetation is decreasing in both NDVI and 457 colour composite analysis. Overall accuracy was estimated to be around 94.3 % for NDVI and for 457 Colour composites was 84.7%. The study area has experienced a change in its land cover between 2001 and 2009 in both NDVI and 457 false colour composite analyses. The whole land cover types have experienced increased in both methods, except high density vegetation. The transformations of spectral vegetation (NDVI product more closely with actual land cover compared with 457 colour composite product.

  2. Effect of removal of hesperis matronalis (Dame's rocket) on species cover of forest understory vegetation in NW indiana

    Science.gov (United States)

    Pavlovic, N.B.; Leicht-Young, S. A.; Frohnapple, K.J.; Grundel, R.

    2009-01-01

    Exotic invasive plant species differ in their effects on indigenous vegetation as evidenced by research evaluating community response to their removal. We used a removal approach to quantify the response of a mesic woodland to the removal versus retention of an invasive plant, Hesperis matronalis (dame's rocket) from paired treatment plots over 3 y. Cover of H. matronalis did not differ between control and treatment plots prior to removal, declined in the removal plots and remained significantly lower in cover compared to the control plots. Removal did not significantly affect species richness and species diversity (evenness, Shannon and Simpson) at the plot scale, but did result in increased species richness overall in the removal plots in the last sampling year when compared to control plots. Non-metric multidimensional scaling ordination analysis indicated a significant compositional change in the spring plant composition of plots over the 3 y, reflecting an increase in exotic woody species. Exotic woody plants, especially Rosa multiflora and Euonymus alatus, increased in cover in response to H. matronalis removal. In the 3 y, neither native nor exotic forbs, nor native woody plants responded to the removal of H. matronalis in a statistically significant manner. The increasing cover of woody invasive plants in response to the removal of H. matronalis has important management implications for restoration of degraded communities.

  3. Relations between topography, wetlands, vegetation cover and stream water chemistry in boreal headwater catchments in Sweden

    Directory of Open Access Journals (Sweden)

    J.-O. Andersson

    2008-05-01

    Full Text Available A large part of the spatial variation of stream water chemistry is found in headwater streams and small catchments. To understand the dominant processes, taking place in small and heterogeneous catchments, spatial and temporal data with high resolution is needed. In most cases available map data has too low quality and resolution to successfully be used in environmental assessments and modelling. In this study 18 forested catchments (1–4 km2 were selected within a 120×50 km area in the county of Värmland in western Sweden. The aim was to test if topographic and vegetation variables derived from official datasets were correlated to stream water chemistry, represented by DOC, Al, Fe and Si content. A GIS was used to analyse the elevation characteristics, generate topographic indices and calculate the percentage of wetlands and a number of vegetation classes. The results clearly show that the topography has a major influence on the occurrence of wetlands, which has a major influence on stream water chemistry. There were very strong correlations between mean slope and percentage wetland, percentage wetland and DOC, mean slope and DOC and mean topographic wetness index and DOC. The conclusion was that official topographic data, despite uncertain or low quality and resolution, could be useful in the prediction of headwater chemistry in boreal forested catchments.

  4. Divergent responses of vegetation cover in Southwestern US ecosystems to dry and wet years at different elevations

    Science.gov (United States)

    Herrmann, Stefanie M.; Didan, Kamel; Barreto-Munoz, Armando; Crimmins, Michael A.

    2016-12-01

    In the semiarid Southwestern United States, prolonged drought conditions since the early 2000s have resulted in widespread declines of the vegetation productivity in this water-constrained ecosystem, as revealed by analyses of the Normalized Difference Vegetation Index (NDVI). However, the spatial pattern of the NDVI response to dry years is not uniform: a divergent response of NDVI to precipitation is observed between the low-lying desert and the high montane forests at elevations above 2,500 meter. We analyzed relationships between 15 years of Moderate Resolution Imaging Spectroradiometer (MODIS) NDVI and gridded climate data (PRISM) along elevation gradients at scales from regional to local. Our elevation-explicit analysis captures the transition from water-limited to temperature-limited ecosystems, with a sign-reversal in the correlation coefficient between precipitation and NDVI observed at about 2,500-3,000m altitude. We suggest warmer temperatures and less snow cover associated with drier years as explanations for high elevation gains in vegetation productivity during dry years.

  5. Evaluation of DGVMs in tropical areas: linking patterns of vegetation cover, climate and fire to ecological processes

    Science.gov (United States)

    D'Onofrio, Donatella; von Hardenberg, Jost; Baudena, Mara

    2017-04-01

    Many current Dynamic Global Vegetation Models (DGVMs), including those incorporated into Earth System Models (ESMs), are able to realistically reproduce the distribution of the most worldwide biomes. However, they display high uncertainty in predicting the forest, savanna and grassland distributions and the transitions between them in tropical areas. These biomes are the most productive terrestrial ecosystems, and owing to their different biogeophysical and biogeochemical characteristics, future changes in their distributions could have also impacts on climate states. In particular, expected increasing temperature and CO2, modified precipitation regimes, as well as increasing land-use intensity could have large impacts on global biogeochemical cycles and precipitation, affecting the land-climate interactions. The difficulty of the DGVMs in simulating tropical vegetation, especially savanna structure and occurrence, has been associated with the way they represent the ecological processes and feedbacks between biotic and abiotic conditions. The inclusion of appropriate ecological mechanisms under present climatic conditions is essential for obtaining reliable future projections of vegetation and climate states. In this work we analyse observed relationships of tree and grass cover with climate and fire, and the current ecological understanding of the mechanisms driving the forest-savanna-grassland transition in Africa to evaluate the outcomes of a current state-of-the-art DGVM and to assess which ecological processes need to be included or improved within the model. Specifically, we analyse patterns of woody and herbaceous cover and fire return times from MODIS satellite observations, rainfall annual average and seasonality from TRMM satellite measurements and tree phenology information from the ESA global land cover map, comparing them with the outcomes of the LPJ-GUESS DGVM, also used by the EC-Earth global climate model. The comparison analysis with the LPJ

  6. Permafrost, Seasonally Frozen Ground, Snow Cover and Vegetation in the USSR

    Science.gov (United States)

    1984-12-01

    Late Quaternary History and the Formation of Sedi- ments in the Marginal and Inland Seas (Pozdnechetvertichnaia Istorlia i Sedimentogenez...rasprostraneniia snezhnogo pokrova na poverkhnosti sushi zemnogo shara). In Geography of Snow Cover (Geo- grafiya Snezhnogo Prokrova). Moscow: Izdat...Papers, 18(3): 198-202. (36-1668) Vigdorchik, M.E. (1980) Arctic Pleistocene History and the Development of Submarine Permafrost. Boulder

  7. 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...

  8. Vegetation cover in an ancient agricultural landscape: the Proszowice Plateau (southern Poland as a case-study

    Directory of Open Access Journals (Sweden)

    Małgorzata Kotańska

    2014-01-01

    Full Text Available The investigations on vegetation cover in the Proszowice Plateau (Małopolska Upland, southern Poland in 1997-1999 were carried out. This vast area (770 sq. km, hitherto not in this respect investigated, is covered with arable fields in 80%. This area has been used for agriculture since the Neolithic age. The aim of the paper is to show the present state of the vegetation and flora in face of the growing man's impact upon living biotas and their environment. The Braun-Blanquet phytosociological method was used, yielding 1030 relevés. In effect, a total of 48 plant associations and communities were found. Plateaux and gently slopes are covered with arable fields. In the cereal communities Vicietum tetraspermae and in the root crops Echinochloo-Setarietum are mostly found. In the wide and shallow stream valleys moist and wet meadows (Calthion, Magnocaricion predominate, and the stands of the xerothermic grassland (Festuco-Brometea occur in places not used for agriculture: on steep escarp-ments between fields and on steep slopes of hills, gullies and stream banks. Small and scarce forests (Querco-Fagetea are preserved on plateaux and on gently slopes. In the stream banks they consist of willow thickets (Salicion and fragments of riverside carr (Alno-Padion. Basing on the relevé material and floristic checklists a total of 860 vascular plant species was recorded, in this 19.2% of rare and endangered. The flora is of lowland character; c. 80% are native species. The characteristic feature of the Proszowice Plateau is the occurrence of the xerothermic grassland and wet meadows, in which species rare in other regions of the country flourish.

  9. The importance of parameterization when simulating the hydrologic response of vegetative land-cover change

    Science.gov (United States)

    White, Jeremy; Stengel, Victoria; Rendon, Samuel; Banta, John

    2017-08-01

    Computer models of hydrologic systems are frequently used to investigate the hydrologic response of land-cover change. If the modeling results are used to inform resource-management decisions, then providing robust estimates of uncertainty in the simulated response is an important consideration. Here we examine the importance of parameterization, a necessarily subjective process, on uncertainty estimates of the simulated hydrologic response of land-cover change. Specifically, we applied the soil water assessment tool (SWAT) model to a 1.4 km2 watershed in southern Texas to investigate the simulated hydrologic response of brush management (the mechanical removal of woody plants), a discrete land-cover change. The watershed was instrumented before and after brush-management activities were undertaken, and estimates of precipitation, streamflow, and evapotranspiration (ET) are available; these data were used to condition and verify the model. The role of parameterization in brush-management simulation was evaluated by constructing two models, one with 12 adjustable parameters (reduced parameterization) and one with 1305 adjustable parameters (full parameterization). Both models were subjected to global sensitivity analysis as well as Monte Carlo and generalized likelihood uncertainty estimation (GLUE) conditioning to identify important model inputs and to estimate uncertainty in several quantities of interest related to brush management. Many realizations from both parameterizations were identified as behavioral in that they reproduce daily mean streamflow acceptably well according to Nash-Sutcliffe model efficiency coefficient, percent bias, and coefficient of determination. However, the total volumetric ET difference resulting from simulated brush management remains highly uncertain after conditioning to daily mean streamflow, indicating that streamflow data alone are not sufficient to inform the model inputs that influence the simulated outcomes of brush management

  10. The importance of parameterization when simulating the hydrologic response of vegetative land-cover change

    Directory of Open Access Journals (Sweden)

    J. White

    2017-08-01

    Full Text Available Computer models of hydrologic systems are frequently used to investigate the hydrologic response of land-cover change. If the modeling results are used to inform resource-management decisions, then providing robust estimates of uncertainty in the simulated response is an important consideration. Here we examine the importance of parameterization, a necessarily subjective process, on uncertainty estimates of the simulated hydrologic response of land-cover change. Specifically, we applied the soil water assessment tool (SWAT model to a 1.4 km2 watershed in southern Texas to investigate the simulated hydrologic response of brush management (the mechanical removal of woody plants, a discrete land-cover change. The watershed was instrumented before and after brush-management activities were undertaken, and estimates of precipitation, streamflow, and evapotranspiration (ET are available; these data were used to condition and verify the model. The role of parameterization in brush-management simulation was evaluated by constructing two models, one with 12 adjustable parameters (reduced parameterization and one with 1305 adjustable parameters (full parameterization. Both models were subjected to global sensitivity analysis as well as Monte Carlo and generalized likelihood uncertainty estimation (GLUE conditioning to identify important model inputs and to estimate uncertainty in several quantities of interest related to brush management. Many realizations from both parameterizations were identified as behavioral in that they reproduce daily mean streamflow acceptably well according to Nash–Sutcliffe model efficiency coefficient, percent bias, and coefficient of determination. However, the total volumetric ET difference resulting from simulated brush management remains highly uncertain after conditioning to daily mean streamflow, indicating that streamflow data alone are not sufficient to inform the model inputs that influence the simulated outcomes

  11. Impacts of changes in vegetation cover on soil water heat coupling in an alpine meadow of the Qinghai-Tibet Plateau, China

    Directory of Open Access Journals (Sweden)

    W. Genxu

    2009-03-01

    Full Text Available Alpine meadow is one of the most widespread grassland types in the permafrost regions of the Qinghai-Tibet Plateau, and the transmission of coupled soil water heat is one of the most crucial processes influencing cyclic variations in the hydrology of frozen soil regions, especially under different vegetation covers. The present study assesses the impact of changes in vegetation cover on the coupling of soil water and heat in a permafrost region. Soil moisture (θv, soil temperature (Ts, soil heat content, and differences in θvTs coupling were monitored on a seasonal and daily basis under three different vegetation covers (30, 65, and 93% on both thawed and frozen soils. Regression analysis of θv vs. Ts plots under different levels of vegetation cover indicates that soil freeze-thaw processes were significantly affected by the changes in vegetation cover. The decrease in vegetation cover of an alpine meadow reduced the difference between air temperature and ground temperature (ΔTa−s, and it also resulted in a decrease in Ts at which soil froze, and an increase in the temperature at which it thawed. This was reflected in a greater response of soil temperature to changes in air temperature (Ta. For ΔTa−s outside the range of −0.1 to 1.0°C, root zone soil-water temperatures showed a significant increase with increasing ΔTa−s; however, the magnitude of this relationship was dampened with increasing vegetation cover. At the time of maximum water content in the thawing season, the soil temperature decreased with increasing vegetation. Changes in vegetation cover also led to variations in θvTs coupling. With the increase in vegetation cover, the surface heat flux decreased. Soil heat storage at 20 cm in

  12. Vegetation cover dynamics of the Mongolian semiarid zone according to multi-temporal LANDSAT imagery (the case of Darkhan test range)

    Science.gov (United States)

    Zharnikova, M. A.; Alymbaeva, ZH B.; Ayurzhanaev, A. A.; Garmaev, E. ZH

    2016-11-01

    At present much attention is given to the spatio-temporal dynamics of plant communities of steppes to assess their response to the current climate changes. In this study, a mapping of a selected modeling polygon was carried out on the basis of data decoding and field surveys of vegetation cover in the semi-arid zone. The resulting large-scale map of actual vegetation reflects the current state of the vegetation cover and its horizontal structure. It is a valuable material for monitoring of changes in the chosen area. With multi-temporal satellite Landsat imagery we consider the vegetation cover dynamics of the test range. To analyze the transformation of the environment by the climatic factors, we compared series of NDVI versus the precipitation and of NDVI versus the temperatures. Then we calculated the degree of correlation between them.

  13. Flutuações de temperatura e umidade do solo em resposta à cobertura vegetal Soil temperature and moisture fluctuations in response to vegetation cover

    Directory of Open Access Journals (Sweden)

    Milson L. de Oliveira

    2005-12-01

    Full Text Available Com o objetivo de verificar as flutuações de temperatura e umidade do solo em resposta à cobertura vegetal, realizou-se um experimento com sete diferentes situações de cobertura do solo, constituídas por solo sem cobertura, presença de vegetação espontânea, cultivo de mucuna e plantio de milho a 0, 30, 60 e 90º em relação ao eixo leste-oeste. Dois meses após a semeadura, em janeiro de 1999, por igual período determinou-se o sombreamento nas entrelinhas do milho, às 8:30, 12:30 e 16:30 h, como também, para todos os tratamentos, a temperatura e umidade do solo nas profundidades de 2,5, 5,0 e 7,5 cm; constatou-se diferença no sombreamento entre o cultivo de milho a 0º e os outros ângulos testados nas determinações matutina e vespertina, mas tais diferenças não foram acompanhadas pela temperatura do solo que, neste caso, registrou valores intermediários entre o solo sem cobertura e os tratamentos com vegetação espontânea e mucuna. No tratamento sem cobertura verificou-se a maior amplitude de variação da temperatura ambiente acima da superfície do solo, registrando-se os menores valores de umidade e os maiores de temperatura do solo.An experimental study was carried out to evaluate the fluctuations of temperature and soil moisture in response to vegetation cover, using the following treatments: bare soil, natural weed cover, velvet bean, and maize at 0, 30, 60 and 90º in relation to a east-west axis. Two months after sowing in January 1999, for similar period the shadowed area between the lines at 8:30, 12:30 and 16:30 h, as well as for all treatments, the temperature and soil moisture at 2.5, 5.0 and 7.5 cm depths were measured. Differences in shadowing between maize cultivated at 0º and all other angles were observed in both morning and afternoon measurements. However, these differences were not accompanied by soil temperature, which showed intermediary values between the bare soil and the treatments with natural

  14. Effects of Land Cover / Land Use, Soil Texture, and Vegetation on the Water Balance of Lake Chad Basin

    Science.gov (United States)

    Babamaaji, R. A.; Lee, J.

    2013-12-01

    Lake Chad Basin (LCB) has experienced drastic changes of land cover and poor water management practices during the last 50 years. The successive droughts in the 1970s and 1980s resulted in the shortage of surface water and groundwater resources. This problem of drought has a devastating implication on the natural resources of the Basin with great consequence on food security, poverty reduction and quality of life of the inhabitants in the LCB. Therefore, understanding the effects of land use / land cover must be a first step to find how they disturb cycle especially the groundwater in the LCB. The abundance of groundwater is affected by the climate change through the interaction with surface water, such as lakes and rivers, and disuse recharge through an infiltration process. Quantifying the impact of climate change on the groundwater resource requires reliable forecasting of changes in the major climatic variables and other spatial variations including the land use/land cover, soil texture, topographic slope, and vegetation. In this study, we employed a spatially distributed water balance model WetSpass to simulate a long-term average change of groundwater recharge in the LCB of Africa. WetSpass is a water balance-based model to estimate seasonal and spatial distribution of surface runoff, interception, evapotranspiration, and groundwater recharge. The model is especially suitable for studying the effect of land use/land cover change on the water regime in the LCB. The present study describes the concept of the model and its application to the development of recharge map of the LCB. The study shows that major role in the water balance of LCB. The mean yearly actual evapotranspiration (ET) from the basin range from 60mm - 400 mm, which is 90 % (69mm - 430) of the annual precipitation from 2003 - 2010. It is striking that about 50 - 60 % of the total runoff is produced on build-up (impervious surfaces), while much smaller contributions are obtained from vegetated

  15. Physical properties of soil cultivated with Jatropha curcas and associated green vegetation covers

    Directory of Open Access Journals (Sweden)

    Willian José Ferreira

    2013-12-01

    Full Text Available The cultivation of physic nut (Jatropha curcas L. is a sustainable option for biodiesel production due to its adaptation to different agro-ecological conditions and its high content of non-edible oil grains. The possibility of its cultivation in degraded low fertility soils makes the physic nut attractive to the Paraíba do Sul Valley region. This study evaluated physical attributes and water processes of an Oxisol which had been previously used for livestock and later converted to experimental farming. The soil was intercropped with perennial herbaceous legumes (Arachis pintoi and Calopogonio muconoides in place of the original cover of Brachiaria brizantha, largely cultivated in the region. We determined the soil texture, the levels of saturation and water retention, soil resistance to root penetration and the basic infiltration rate of water into the soil (VIB. The soil resistance to root penetration in B. brizantha ranged from high to moderate at 30 cm depth, while the addition of perennial herbaceous legumes as cover crops intercropped with Jatropha reduced this resistance and increased the average soil VIB from 4 mm h-1 (B. brizantha to 33 mm h-1. We conclude that the association of herbaceous legumes with Jatropha contributed to the improvement of the soil’s physical properties.

  16. Chemical composition of overland flow produced on soils covered with vegetative ash

    Directory of Open Access Journals (Sweden)

    M.B. Bodí

    2013-05-01

    Full Text Available The objective of this study was to ascertain the differences between the soluble elements of ash obtained under laboratory conditions and the dissolved in overland flow from soils covered with a layer of ash. The overland flow was obtained during series of rainfall simulations over soils covered with two different types of ash. This study indicates that the soluble elements released from ash can modify water quality increasing its pH, electrical conductivity and especially cation content. The nutrients solubilised are not necessarily the same as the elemental composition of ash itself. Runoff composition depends on the volume of water produced, on the solubility of the ash components and on the chemical interactions with water from rainfall and soil. After the first intense rain event, most of the elements are solubilised and lixiviated or washed out, however, some of them may increase in the runoff or soil water some weeks later due to chemical interactions with water from rainfall and soil nutrients.

  17. Extension of the mcplots Project and Rivet to Cover Specific Needs Arising from Heavy-Ion Analyses

    CERN Document Server

    Volkel, Benedikt

    2016-01-01

    The comparison between experimental data and Monte Carlo event generator output is a important tool in high energy and heavy-ion physics. It is crucial for the search of new physics, the test of theory and models, the determination of detector effects and the development of event generators. The MC analysis tool Rivet is especially made to cover this comparison procedure. Both, analysis scripts corresponding to a experimental analysis as well as the histogram data is provided. The analysis scripts can be applied to MC output producing histogram data which can be compared to experimental data immediately. mcplots steers the Rivet analysis and MC run, automizes the plotting and provides a web page where produced plots can be accessed. However, some analyses in heavy-ion physics are either very cumbersome to implement or cannot be covered by the current Rivet and mcplots workflow at all. This report summarizes first prototypes of extensions implemented to cover such analyses as part of the summer student project...

  18. Vegetation cover and land use impacts on soil water repellency in an Urban Park located in Vilnius, Lithuania

    Science.gov (United States)

    Pereira, Paulo; Cerda, Artemi

    2015-04-01

    It is strongly recognized that vegetation cover, land use have important impacts on the degree of soil water repellency (SWR). Soil water repellency is a natural property of soils, but can be induced by natural and anthropogenic disturbances as fire and soil tillage (Doerr et al., 2000; Urbanek et al., 2007; Mataix-Solera et al., 2014). Urban parks are areas where soils have a strong human impact, with implications on their hydrological properties. The aim of this work is to study the impact of different vegetations cover and urban soils impact on SWR and the relation to other soil variables as pH, Electrical Conductivity (EC) and soil organic matter (SOM) in an urban park. The study area is located in Vilnius city (54°.68' N, 25°.25' E). It was collected 15 soil samples under different vegetation cover as Pine (Pinus Sylvestris), Birch (Alnus glutinosa), Penduculate Oak (Quercus robur), Platanus (Platanus orientalis) and other human disturbed areas as forest trails and soils collected from human planted grass. Soils were taken to the laboratory, air-dried at room temperature and sieved with the 3600 (extremely water repellent). The results showed significant differences among the different vegetation cover (Kruskal-Wallis H=20.64, pgrass were significantly higher than Platanus soil. The soils from Pine, Birch, Penduculate Oak, forest trails and planted grass were majorly severely water repellent, while Platanus soils were mostly strong water repellent. Soil water repellency of Pine soils had a significant negative correlation with pH (-0.52, ppH (-0.88, ppH, EC and SOM. Acknowledgments POSTFIRE (Soil quality, erosion control and plant cover recovery under different post-fire management scenarios, CGL2013-47862-C2-1-R), funded by the Spanish Ministry of Economy and Competitiveness; Fuegored; RECARE (Preventing and Remediating Degradation of Soils in Europe Through Land Care, FP7-ENV-2013-TWO STAGE), funded by the European Commission; and for the COST action ES

  19. Evaluation of Spatiotemporal Variations of Global Fractional Vegetation Cover Based on GIMMS NDVI Data from 1982 to 2011

    Directory of Open Access Journals (Sweden)

    Donghai Wu

    2014-05-01

    Full Text Available Fractional vegetation cover (FVC is an important biophysical parameter of terrestrial ecosystems. Variation of FVC is a major problem in research fields related to remote sensing applications. In this study, the global FVC from 1982 to 2011 was estimated by GIMMS NDVI data, USGS global land cover characteristics data and HWSD soil type data with a modified dimidiate pixel model, which considered vegetation and soil types and mixed pixels decomposition. The evaluation of the robustness and accuracy of the GIMMS FVC with MODIS FVC and Validation of Land European Remote sensing Instruments (VALERI FVC show high reliability. Trends of the annual FVCmax and FVCmean datasets in the last 30 years were reported by the Mann–Kendall method and Sen’s slope estimator. The results indicated that global FVC change was 0.20 and 0.60 in a year with obvious seasonal variability. All of the continents in the world experience a change in the annual FVCmax and FVCmean, which represents biomass production, except for Oceania, which exhibited a significant increase based on a significance level of p = 0.001 with the Student’s t-test. Global annual maximum and mean FVC growth rates are 0.14%/y and 0.12%/y, respectively. The trends of the annual FVCmax and FVCmean based on pixels also illustrated that the global vegetation had turned green in the last 30 years. A significant trend on the p = 0.05 level was found for 15.36% of the GIMMS FVCmax pixels on a global scale (excluding permanent snow and ice, in which 1.8% exhibited negative trends and 13.56% exhibited positive trends. The GIMMS FVCmean similarly produced a total of 16.64% significant pixels with 2.28% with a negative trend and 14.36% with a positive trend. The North Frigid Zone represented the highest annual FVCmax significant increase (p = 0.05 of 25.17%, which may be caused mainly by global warming, Arctic sea-ice loss and an advance in growing seasons. Better FVC predictions at large regional scales

  20. Streptococcus agalactiae infective endocarditis complicated by large vegetations at aortic valve cusps along with intracoronary extension: An autopsy case report.

    Science.gov (United States)

    Ro, Ayako

    2016-01-01

    Streptococcus agalactiae infective endocarditis is a rare condition with high mortality owing to complications of large vegetations and systemic emboli. A 49-year-old man was found dead in his house. He had a history of hepatic cirrhosis and had been diagnosed with type 2 diabetes 2years previously. He had presented with a high fever 10days before his death. An autopsy revealed 50mL of purulent pericardial effusion, and S. agalactiae was detected from the culture of this pericardial effusion. Two slender rope-like vegetations were present at the right aortic valve cusp and noncoronary aortic valve cusp. The vegetation at the right aortic valve cusp extended into the right coronary artery. The right coronary artery was broadly occluded by white rod-like material. The mitral valves were also affected, and the posterior papillary muscle was ruptured. Myocardial infarction was not observed. Systemic microscopic Gram-positive bacterial masses were observed in several organs. The death was attributed to acute myocardial ischemia caused by occlusive intracoronary extension of the vegetation at the proximal right coronary artery.

  1. Land use and vegetation cover on native symbionts and interactions with cowpea

    Directory of Open Access Journals (Sweden)

    Beatriz C. F. Rocha

    Full Text Available ABSTRACT Arbuscular mycorrhizal fungi and rhizobia are important components of agroecosystems and they respond to human interference. The objective of this study was to investigate native communities of those microorganisms in soil collected under the native forest, four pastures (Brachiaria brizantha, Panicum maximum, Arachis pintoi and Stylosanthes guianensis and a fallow soil after maize cultivation, in interaction with cowpea (Vigna unguculata. The cowpea grew in a greenhouse until flowering. They were randomly distributed depending on soil, in five replications. The lowest mycorrhizal fungi sporulation and mycorrhizal root colonization occurred under the Panicum and forest soil. In the soils under forest and Stylosanthes, the cowpea did not exhibit nodules and grew less. Among the anthropized areas, the effect was variable, with stimulus to the multiplication and symbiosis of these microorganisms, except in areas of Panicum and Stylosanthes. When the native vegetation is substituted by pasture or farming, the mycorrhizal fungi and rhizobia proliferation predominate. However, the effect and its magnitude depends on the grown plant species, with reflects on the plant species in succession, such as the cowpea.

  2. 重庆市主城区热岛效应与植被覆盖关系研究%Relationship between urban heat island effect and vegetation cover in core area of Chongqing City

    Institute of Scientific and Technical Information of China (English)

    杨春华; 雷波; 张晟

    2013-01-01

    为了研究重庆市主城区热岛效应与植被覆盖的关系,利用重庆市主城区2008年TM遥感数据,提取了NDVI(植被归一化)指数,并结合野外实地调查,获取了地表植被覆盖度数据,利用GIS空间分析技术及数理统计方法进行了分析。结果表明,重庆市主城区热岛效应明显,在空间上呈大片、连续分布状态;热岛效应与植被覆盖度呈负相关关系,即随着植被覆盖度的提高而降低,在植被覆盖度高于50%后热岛效应消失。城市绿地面积越大,内外温差也越大,从而形成热岛中的“冷岛”,城市绿地对热岛效应具有重要的减缓作用。%In order to study the relationship between urban heat island effect and vegetation cover in the core area of Chongqing City, the NDVI (Normalized Difference Vegetation Index) is extracted from TM images of the core area of the city in 2008, and the land surface’s vegetation cover data are obtained by field investigation. The relationship between vegetation cover and urban heat island effect was analyzed on the basis of GIS data and corresponding mathematical statistics. The analysis results show that the urban heat island effect in the city core area is very obvious, which extensively appears in a large and connected areas; the urban heat island effect is negatively interrelated with vegetation cover, it reduces with the increase of vegetation cover rate and disappears if the vegetation cover rate is greater than 50%. The bigger area of urban green space is, the bigger temperature differ-ence exists, thereby forming a"cool island" in the heat island. Therefore, the urban green space has an important role in mitiga-ting the urban heat island effect.

  3. Unmasking the soil cover's disruption by use of a dynamic model of measurement aerospace parameters of ground vegetation

    Directory of Open Access Journals (Sweden)

    E. V. Vysotskaya

    2016-03-01

    Full Text Available The "Introduction" describes topicality and importance of revealing the soil cover's disruption for a wide range of fields. It was shown that spectral brightness and colorimetric parameters of ground vegetation can be used for this task. However, a traditional scheme of data processing for remote sensing requires a long-term observations and can not always be applied, if quick decision-making is necessary or there is lack of information. Such cases require the use of special methods, one of which is a dynamic model developed with authors' participation based on the following basic relationships: (+,- (-, - (+, 0, (-, 0 (0,0. The section "Brief description of a dynamic model" describes the basic principles of dynamic systems used to solve the problem. Using above-mentioned relationships, the dynamics of a system consisting of several components is constructed and its main properties are listed. The main feature of this model is that the identification of structure and parameters of the dynamic system does not required sequential order of observations (as for models based on time series. This feature of the model enables for identifying the system's parameters of dynamics of the natural system to use information from a single picture taken from the spacecraft rather than long-term observations. The section "Materials and Methods" describes specific colorimetric parameters used to analyze the vegetation cover. The section "Obtained results" contains an example of the model's application to a satellite image for detecting the differences in two sites of a field with vegetation. One site is a recultivated area near the liquidated gas-oil well, another site is non-recultivated area at a considerable distance from the well (500-1000 m. The simulation results are described by eight signed graphs (4 graphs for each sites, whose structure allows to identify the system differences between the two cases. The section "Conclusions" summarizes the results of

  4. Vegetation Cover Mapping Based on Remote Sensing and Digital Elevation Model Data

    Science.gov (United States)

    Korets, M. A.; Ryzhkova, V. A.; Danilova, I. V.; Prokushkin, A. S.

    2016-06-01

    An algorithm of forest cover mapping based on combined GIS-based analysis of multi-band satellite imagery, digital elevation model, and ground truth data was developed. Using the classification principles and an approach of Russian forest scientist Kolesnikov, maps of forest types and forest growing conditions (FGC) were build. The first map is based on RS-composite classification, while the second map is constructed on the basis of DEM-composite classification. The spatial combination of this two layers were also used for extrapolation and mapping of ecosystem carbon stock values (kgC/m2). The proposed approach was applied for the test site area (~3600 km2), located in the Northern Siberia boreal forests of Evenkia near Tura settlement.

  5. Trends in woody vegetation cover in the Kruger National Park, South Africa, between 1940 and 1998

    CSIR Research Space (South Africa)

    Eckhardt, HC

    2000-06-01

    Full Text Available avec de brefs intervalles depuis 40 ans, alors que le de´clin ge´ne´ral des grands arbres semble eˆtre le re´sultat d’une interaction entre les feux, re´guliers et fre´- quents, et la pre´sence des e´le´phants. On discute de ce que cela implique... 21.8b 22.1b granite transects 6 13.4 12.3 9.4 7 11.3 9.2 4.8 8 14.8 5.7 3.6 9 8.1 – 3.6 Mean for 11.9a 9.1b 4.3c basalt transects past 50 years, the cover has increased on granites and decreased on basalts (Table 2). The trend was weaker...

  6. Development and validation of extensive growth and growth boundary models for psychrotolerant pseudomonads in seafood, meat and vegetable products

    DEFF Research Database (Denmark)

    Martinez Rios, Veronica; Dalgaard, Paw

    Extensive growth and growth boundary models were developed and validated for psychrotolerant pseudomonads growing in seafood, meat and vegetable products. The new models were developed by expanding anexisting cardinal parameter-type model for growth of pseudomonads in milk (Martinez-Rios et al...... parameters and their interactive effects. It was successfully validated using 319growth rates (μmax -values) for psychrotolerant pseudomonads in seafood and meat products. These data from literature (n=291) or own experiments (n=28) resulted in bias and accuracy factor values of 1.14 and 1.28, respectively......, when observed and predicted μmax -values were compared. Thus, on average μmax -values for seafood and meat products were overestimated by 14%. Additionally, the reference growth rate parameter μref25˚C was calibrated by fitting the model to 21 μmax -values in vegetable products. This resulted in a μref...

  7. Monitoring deterioration of vegetation cover in the vicinity of smelting industry, using statistical methods and TM and ETM(+) imageries, Sarcheshmeh copper complex, Central Iran.

    Science.gov (United States)

    Rastmanesh, F; Moore, F; Kharrati-Kopaei, M; Behrouz, M

    2010-04-01

    Simple statistical methods on Normalized Difference Vegetation Index (NDVI) and bands 3 and 4 data of relatively coarse resolution Thematic Mapper (TM) and Enhanced Thematic Mapper plus (ETM(+)) imageries were used to investigate the impacts of air pollution on the deterioration of the vegetation cover in the Sarcheshmeh copper complex of central Iran. Descriptive statistics and k-means cluster analysis indicated that vegetation deterioration had already started in the prevailing wind directions. The results show that combination of simple statistical methods and satellite imageries can be used as effective monitoring tools to indicate vegetation stress even in regions of sparse vegetation. Despite various possible perturbing factors upon NDVI, this index remains to be a valuable quantitative vegetation monitoring tool.

  8. Effect of some improvement works on the floristic composition of the vegetal cover in Nardus stricta grasslands

    Directory of Open Access Journals (Sweden)

    Teodor Maruşca

    2014-05-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 The study of the floristic composition of Nardus stricta grasslands improved through fertilisation, amendment and re-sowing for 18 years points out a structural change of the vegetal cover compared to the initial state of the floristic composition. During this time interval, the share of Nardus stricta dropped from 40 to 14% in the variants grazed rationally (without treatments, from 40 to 4% in the variant fertilised with NPK and grazed, and from 40% to the total disappearance of the species in the variants fertilised with NPK, amended, and re-sowed. The species Nardus stricta was replaced by high-fodder value species such as Agrostis capillaris, Poa pratensis, and Trifolium repens.

  9. The application of very high resolution satellite image in urban vegetation cover investigation: a case study of Xiamen City

    Institute of Scientific and Technical Information of China (English)

    CHENGChengqi; LiBin; MATing

    2003-01-01

    With the technological improvements of satellite sensors, we will acquire more information about the earth so that we have reached a new application epoch of observation on earth environmental change and cartography. But with the enhancement of spatial resolution, some questions have arisen in the application of using traditional image processing and classification methods. Aiming for such questions, we studied the application of IKONOS very high resolution image (1 m) in Xiamen City on Urban Vegetation Cover Investigation and discussed the difference between the very high resolution image and traditional low spatial resolution image at classification,information abstraction etc. It is an advantageous test for the large-scale application of very high resolution data in the future.

  10. Temporal and Spatial Variations of Vegetation Cover in Xinjiang from 2002 to 2015 and Their Response to Climate

    Science.gov (United States)

    Liu, S. S.; Zhang, Q.; Li, X. C.; Song, W. J.; Yang, J. N.; Liu, X. J.

    2017-07-01

    In this paper, the dataset of normalized difference vegetation indexes (NDVIs) in the arid region in Xinjiang from 2002 to 2015 as well as the climate data from 52 meteorological stations are utilized and the temporal and spatial variations of NDVI in recent years and their response to temperature and precipitation are analyzed in combination with various methods such as the maximum value analysis, correlation analysis and spatial analysis. It is concluded that in the past 14 years, the annual maximum NDVIs of Xinjiang presented a moderate rising tendency; Under the influence of the global background, the temperature and precipitation also showed different degrees of increase, which showed a significant increase in temperature. The annual maximum NDVI had a significant correlation with the annual precipitation (correlation coefficient: 0.634), but no obvious correlation was identified between the annual maximum NDVI and the annual average temperature (correlation coefficient: 0.279). To this end, regarding to the climatic factors, the influence of precipitation on the vegetation cover is higher than that of temperature.

  11. The landscape configuration of zoonotic transmission of Ebola virus disease in West and Central Africa: interaction between population density and vegetation cover.

    Science.gov (United States)

    Walsh, Michael G; Haseeb, Ma

    2015-01-01

    Ebola virus disease (EVD) is an emerging infectious disease of zoonotic origin that has been responsible for high mortality and significant social disruption in West and Central Africa. Zoonotic transmission of EVD requires contact between susceptible human hosts and the reservoir species for Ebolaviruses, which are believed to be fruit bats. Nevertheless, features of the landscape that may facilitate such points of contact have not yet been adequately identified. Nor have spatial dependencies between zoonotic EVD transmission and landscape structures been delineated. This investigation sought to describe the spatial relationship between zoonotic EVD transmission events, or spillovers, and population density and vegetation cover. An inhomogeneous Poisson process model was fitted to all precisely geolocated zoonotic transmissions of EVD in West and Central Africa. Population density was strongly associated with spillover; however, there was significant interaction between population density and green vegetation cover. In areas of very low population density, increasing vegetation cover was associated with a decrease in risk of zoonotic transmission, but as population density increased in a given area, increasing vegetation cover was associated with increased risk of zoonotic transmission. This study showed that the spatial dependencies of Ebolavirus spillover were associated with the distribution of population density and vegetation cover in the landscape, even after controlling for climate and altitude. While this is an observational study, and thus precludes direct causal inference, the findings do highlight areas that may be at risk for zoonotic EVD transmission based on the spatial configuration of important features of the landscape.

  12. The landscape configuration of zoonotic transmission of Ebola virus disease in West and Central Africa: interaction between population density and vegetation cover

    Directory of Open Access Journals (Sweden)

    Michael G. Walsh

    2015-01-01

    Full Text Available Ebola virus disease (EVD is an emerging infectious disease of zoonotic origin that has been responsible for high mortality and significant social disruption in West and Central Africa. Zoonotic transmission of EVD requires contact between susceptible human hosts and the reservoir species for Ebolaviruses, which are believed to be fruit bats. Nevertheless, features of the landscape that may facilitate such points of contact have not yet been adequately identified. Nor have spatial dependencies between zoonotic EVD transmission and landscape structures been delineated. This investigation sought to describe the spatial relationship between zoonotic EVD transmission events, or spillovers, and population density and vegetation cover. An inhomogeneous Poisson process model was fitted to all precisely geolocated zoonotic transmissions of EVD in West and Central Africa. Population density was strongly associated with spillover; however, there was significant interaction between population density and green vegetation cover. In areas of very low population density, increasing vegetation cover was associated with a decrease in risk of zoonotic transmission, but as population density increased in a given area, increasing vegetation cover was associated with increased risk of zoonotic transmission. This study showed that the spatial dependencies of Ebolavirus spillover were associated with the distribution of population density and vegetation cover in the landscape, even after controlling for climate and altitude. While this is an observational study, and thus precludes direct causal inference, the findings do highlight areas that may be at risk for zoonotic EVD transmission based on the spatial configuration of important features of the landscape.

  13. Analysis of vegetation and land cover dynamics in north-western Morocco during the last decade using MODIS NDVI time series data

    Directory of Open Access Journals (Sweden)

    C. Höpfner

    2011-11-01

    Full Text Available Vegetation phenology as well as the current variability and dynamics of vegetation and land cover, including its climatic and human drivers, are examined in a region in north-western Morocco that is nearly 22 700 km2 big. A gapless time series of Normalized Differenced Vegetation Index (NDVI composite raster data from 29 September 2000 to 29 September 2009 is utilised. The data have a spatial resolution of 250 m and were acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS sensor.

    The presented approach allows to compose and to analyse yearly land cover maps in a widely unknown region with scarce validated ground truth data by deriving phenological parameters. Results show that the high temporal resolution of 16 d is sufficient for (a determining local land cover better than global land cover classifications of Plant Functional Types (PFT and Global Land Cover 2000 (GLC2000 and (b for drawing conclusions on vegetation dynamics and its drivers. Areas of stably classified land cover types (i.e. areas that did not change their land cover type show climatically driven inter- and intra-annual variability with indicated influence of droughts. The presented approach to determine human-driven influence on vegetation dynamics caused by agriculture results in a more than ten times larger area compared with stably classified areas. Change detection based on yearly land cover maps shows a gain of high-productive vegetation (cropland of about 259.3 km2. Statistically significant inter-annual trends in vegetation dynamics during the last decade could however not be discovered. A sequence of correlations was respectively carried out to extract the most important periods of rainfall responsible for the production of green biomass and for the extent of land cover types. Results show that mean daily precipitation from 1 October to 15 December has high correlation results (max. r2=0.85 on an intra

  14. Vegetation cover and topography rather than human disturbance control gully density and sediment production on the Chinese Loess Plateau

    Science.gov (United States)

    Zhao, Jianlin; Vanmaercke, Matthias; Chen, Longqian; Govers, Gerard

    2016-12-01

    The factors controlling topsoil erosion rates on the Chinese Loess Plateau (CLP) are currently relatively well understood and topsoil erosion rates can now be relatively accurately estimated. This is, however, not the case for non-topsoil erosion (sediment production by gullying and landslides): while it is well known that these processes produce significant amounts of sediment, the factors controlling their intensity and spatial distribution on the CLP are less well understood. In this study we quantified the contribution of non-topsoil erosion to total sediment production on the CLP and investigated which factors control spatial and temporal variations in non-topsoil erosion. We estimated non-topsoil erosion rates (ENT) by comparing the measured average sediment yields of 46 gauged catchments for the 1950-1970 period, when soil conservation measures were nearly absent in the area, with predicted topsoil erosion rates (using a recently developed empirical model). In addition, gully density was estimated in each catchment using Google Earth data. Our results showed that the area-weighted average catchment erosion rate (E) and ENT were 58.60 ± 51.80 and 48.68 ± 49.78 t ha- 1 yr- 1 respectively for the studied catchments. The sediment contribution of non-topsoil erosion to total sediment production ranged between ca. 0 and 97% with a mean of 70 ± 25%. Both E and ENT were significantly correlated to longitudinal river slope, land use, NDVI, and gully density. However, gully density was the only variable explaining a major part of the variance in both E (60%) and ENT (57%). Gully density itself was significantly related to topography and vegetation cover but not to rainfall erosivity. Importantly, gully density was not only related to overall slope steepness, but also to the longitudinal slope of the river network and the hypsometric integral, suggesting that not only land cover disturbance but also tectonic uplift controls gully density and erosion rates. The

  15. Annual rainfall based analysis of streamflow regime dynamics following vegetation cover changes in temperate and little rain catchments in Japan

    Science.gov (United States)

    Hosoda, I.

    2013-12-01

    Relationship between forest and runoff has been widely studied by paired catchment method. However, paired catchment method is not proper for long-term analysis because it is difficult to keep up the reference catchment in a constant condition for years. Therefore this study tried to find relationship between forest and runoff through relationship between annual rainfall and runoff. The study sites are the Kita-tani (17.3 ha, 36-246 m) and the Minami-tani (22.6 ha, 50-257 m) in the Tatsunokuchi-yama experimental watershed (34°42'N, 133°58'E) where measurement started in 1937. Since streamflow regime is highly influenced by change in catchment water storage, three-year weighted mean annual rainfall was applied. Runoff values for each year were segmental sums of streamflow regime curve (annual, 1st-95th, 96th-185th, 186th-275th, 276th-355th, and after 355th). In the relationships between the weighted annual rainfall and the runoff values for each segment in the whole period, the data in the period of 1998-2003 while the vegetation was most stable in the past 75 years in the both catchments were linearly distributed in the base part of scatter plot (r=0.61-0.96). These regression lines were used as criteria. Difference between observed runoff and estimated runoff by the regression equation (dQ) was calculated, and examined time series. The regression period was about 20 years past after severe pine disease around 1980, and the catchments were covered with Quercus serrata dominant mixed forest. In the both catchments, annual dQ in the period of 1937-2012 ranged from -10% to 30% of annual rainfall, and over 90% of annual dQ were consisted of 1-95th dQ. dQ variations for each segment tend to increase following pine disease and forest fire, and tend to approach toward zero following forest recovery. In recent years, dQ of the segments after 95th decreased less than zero in contrast to annual dQ increased. Similar tendency appeared in the early years in the Minami

  16. Moisture content behaviour in extensive green roofs during dry periods: The influence of vegetation and substrate characteristics

    Science.gov (United States)

    Berretta, Christian; Poë, Simon; Stovin, Virginia

    2014-04-01

    Evapotranspiration (ET) is a key parameter that influences the stormwater retention capacity, and thus the hydrological performance, of green roofs. This paper investigates how the moisture content in extensive green roofs varies during dry periods due to evapotranspiration. The study is supported by 29 months continuous field monitoring of the moisture content within four green roof test beds. The beds incorporated three different substrates, with three being vegetated with sedum and one left unvegetated. Water content reflectometers were located at three different soil depths to measure the soil moisture profile and to record temporal changes in moisture content at a five-minute resolution. The moisture content vertical profiles varied consistently, with slightly elevated moisture content levels being recorded at the deepest substrate layer in the vegetated systems. Daily moisture loss rates were influenced by both temperature and moisture content, with reduced moisture loss/evapotranspiration when the soil moisture was restricted. The presence of vegetation resulted in higher daily moisture loss. Finally, it is demonstrated that the observed moisture content data can be accurately simulated using a hydrologic model based on water balance and two conventional Potential ET models (Hargreaves and FAO56 Penman-Monteith) combined with a soil moisture extraction function. Configuration-specific correction factors have been proposed to account for differences between green roof systems and standard reference crops.

  17. The Energy Impact in Buildings of Vegetative Solutions for Extensive Green Roofs in Temperate Climates

    Directory of Open Access Journals (Sweden)

    Benedetta Barozzi

    2016-08-01

    Full Text Available Many bibliographical studies have highlighted the positive effects of green roofs as technological solutions both for new and renovated buildings. The one-year experimental monitoring campaign conducted has investigated, in detail, some aspects related to the surface temperature variation induced by the presence of different types of vegetation compared to traditional finishing systems for flat roofs and their impact from an energy and environmental point of view. The results obtained underlined how an appropriate vegetative solution selection can contribute to a significant reduction of the external surface temperatures (10 °C–20 °C for I > 500 W/m2 and 0 °C–5 °C for I < 500 W/m2, regardless of the season compared to traditional flat roofs. During the winter season, the thermal gradients of the planted surface temperatures are close to zero compared to the floor, except under special improving conditions. This entails a significant reduction of the energy loads from summer air conditioning, and an almost conservative behavior with respect to that from winter heating consumption. The analysis of the inside growing medium temperatures returned a further interesting datum, too: the temperature gradient with respect to surface temperature (annual average 4 °C–9 °C is a function of solar radiation and involves the insulating contribution of the soil.

  18. Shelf life extension of fresh fruit and vegetables by chitosan treatment.

    Science.gov (United States)

    Romanazzi, Gianfranco; Feliziani, Erica; Baños, Silvia Bautista; Sivakumar, Dharini

    2017-02-11

    Among alternatives that are currently under investigation to replace the use of synthetic fungicides to control postharvest diseases in fresh produce and to extend their shelf life, chitosan application has shown promising disease control, at both preharvest and postharvest stages. Chitosan shows a dual mode of action, on the pathogen and on the plant, as it reduces the growth of decay-causing fungi and foodborne pathogens and induces resistance responses in the host tissues. Chitosan coating forms a semipermeable film on the surface of fruit and vegetables, thereby delaying the rate of respiration, decreasing weight loss, maintaining the overall quality, and prolonging the shelf life. Moreover, the coating can provide a substrate for incorporation of other functional food additives, such as minerals, vitamins, or other drugs or nutraceutical compounds that can be used to enhance the beneficial properties of fresh commodities, or in some cases the antimicrobial activity of chitosan. Chitosan coating has been approved as GRAS substance by USFDA, and its application is safe for the consumer and the environment. This review summarizes the most relevant and recent knowledge in the application of chitosan in postharvest disease control and maintenance of overall fruit and vegetable quality during postharvest storage.

  19. Vegetation-climate feedback causes reduced precipitation and tropical rainforest cover in CMIP5 regional Earth system model simulation over Africa

    Science.gov (United States)

    Wu, M.; Smith, B.; Samuelsson, P.; Rummukainen, M.; Schurgers, G.

    2012-12-01

    We applied a coupled regional climate-vegetation model, RCA-GUESS (Smith et al. 2011), over the CORDEX Africa domain, forced by boundary conditions from a CanESM2 CMIP5 simulation under the RCP8.5 future climate scenario. The simulations were from 1961 to 2100 and covered the African continent at a horizontal grid spacing of 0.44°. RCA-GUESS simulates changes in the phenology, productivity, relative cover and population structure of up to eight plant function types (PFTs) in response to forcing from the climate part of the model. These vegetation changes feed back to simulated climate through dynamic adjustments in surface energy fluxes and surface properties. Changes in the net ecosystem-atmosphere carbon flux and its components net primary production (NPP), heterotrophic respiration and emissions from biomass burning were also simulated but do not feed back to climate in our model. Constant land cover was assumed. We compared simulations with and without vegetation feedback switched "on" to assess the influence of vegetation-climate feedback on simulated climate, vegetation and ecosystem carbon cycling. Both positive and negative warming feedbacks were identified in different parts of Africa. In the Sahel savannah zone near 15°N, reduced vegetation cover and productivity, and mortality caused by a deterioration of soil water conditions led to a positive warming feedback mediated by decreased evapotranspiration and increased sensible heat flux between vegetation and the atmosphere. In the equatorial rainforest stronghold region of central Africa, a feedback syndrome characterised by reduced plant production and LAI, a dominance shift from tropical trees to grasses, reduced soil water and reduced rainfall was identified. The likely underlying mechanism was a decline in evaporative water recycling associated with sparser vegetation cover, reminiscent of Earth system model studies in which a similar feedback mechanism was simulated to force dieback of tropical

  20. 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.

  1. Interaction of vegetative cover and N addition on soil CO2 efflux in an oak savanna ecosystem

    Science.gov (United States)

    Morris, Kendalynn; Wutzler, Thomas; Poehlmann, Marco; Nair, Richard; Migliavacca, Mirco; Schrumpf, Marion

    2017-04-01

    Numerous fertilization experiments have demonstrated that nitrogen (N) addition leads to shifts in soil respiration. In forest ecosystems N addition typically results in decreased soil respiration, while grasslands generally have the opposite response. Neither result is universal because the direction of the response is dictated by site-specific soil and vegetation properties. The MaNiP large scale nutrient manipulation experiment aims at studying ecosystem properties, such as soil respiration, by altering nitrogen (N) and phosphorus (P) stoichiometry. The experimental site is a dehesa, an oak-savanna ecosystem in Extremadura, Spain. The tree-grass structure results in a mosaic of two distinct soils coexisting within the same parent material and climatic conditions. Soils beneath trees are richer in organic matter, have a higher C:N, and a relatively well developed A-horizon compared to soils in the open grassland. This offers an ideal opportunity to study how soil properties modify responses to stoichiometric shifts. We established automated respiration chambers in both of these soil types within plots fertilized with N and where no nitrogen was added (Control). By comparing the magnitude of near continuous CO2 fluxes in these chambers with onsite Eddy Covariance Towers, we can quantify the relative contribution of soils under trees and in open grassland to ecosystem respiration and how the nutrient treatments moderate their responses to seasonal fluctuations in temperature and moisture. Preliminary results suggest that soil respiration increased with fertilization and that fluxes underneath tree canopies are more responsive, likely due to higher C content and microclimatic properties. Further analysis will determine if fertilization influences annual cycles in respiration or the sensitivity of respiration to climatic drivers and pulses (e.g., rain). Our initial conclusion is that vegetation cover modifies the interaction of soil C and N cycle in this ecosystem.

  2. Assessment of the vegetation cover in a burned area 22-years ago using remote sensing techniques and GIS analysis (Sierra de las Nieves, South of Spain).

    Science.gov (United States)

    Martínez-Murillo, Juan F.; Remond, Ricardo; Ruiz-Sinoga, José D.

    2015-04-01

    The study aim was to characterize the vegetation cover in a burned area 22-years ago considering the previous situation to wildfire in 1991 and the current one in 2013. The objectives were to: (i) compare the current and previous vegetation cover to widlfire; (ii) evaluate whether the current vegetation has recovered the previous cover to wildfire; and (iii) determine the spatial variability of vegetation recovery after 22-years since the wildfire. The study area is located in Sierra de las Nieves, South of Spain. It corresponds to an area affected by a wildfire in August 8th, 1991. The burned area was equal to 8156 ha. The burn severity was spatially very high. The main geographic features of the burned area are: mountainous topography (altitudes ranging from 250 m to 1500 m; slope gradient >25%; exposure mainly southfacing); igneous (peridotites), metamorphic (gneiss) and calcareous rocks (limestones); and predominant forest land use (Pinus pinaster sp. woodlands, 10%; pinus opened forest + shrubland, 40%; shrubland, 35%; and bare soil + grassland, 15%). Remote sensing techniques and GIS analysis has been applied to achieve the objectives. Landsat 5 and Landsat 8 images were used: July 13th, 1991 and July 1st, 2013, for the previous wildfire situation and 22-years after, respectively. The 1990 CORINE land cover was also considered to map 1991 land uses prior the wildfire. Likewise, the Andalucía Regional Government wildfire historic records were used to select the burned area and its geographical limit. 1991 and 2013 land cover map were obtained by means of object-oriented classifications. Also, NDVI and PVI1 vegetation indexes were calculated and mapped for both years. Finally, some images transformations and kernel density images were applied to determine the most recovered areas and to map the spatial concentration of bare soil and pine cover areas in 1991 and 2013, respectively. According to the results, the combination of remote sensing and GIS analysis let

  3. The Application of Remote Sensing Data to GIS Studies of Land Use, Land Cover, and Vegetation Mapping in the State of Hawaii

    Science.gov (United States)

    Hogan, Christine A.

    1996-01-01

    A land cover-vegetation map with a base classification system for remote sensing use in a tropical island environment was produced of the island of Hawaii for the State of Hawaii to evaluate whether or not useful land cover information can be derived from Landsat TM data. In addition, an island-wide change detection mosaic combining a previously created 1977 MSS land classification with the TM-based classification was produced. In order to reach the goal of transferring remote sensing technology to State of Hawaii personnel, a pilot project was conducted while training State of Hawaii personnel in remote sensing technology and classification systems. Spectral characteristics of young island land cover types were compared to determine if there are differences in vegetation types on lava, vegetation types on soils, and barren lava from soils, and if they can be detected remotely, based on differences in pigments detecting plant physiognomic type, health, stress at senescence, heat, moisture level, and biomass. Geographic information systems (GIS) and global positioning systems (GPS) were used to assist in image rectification and classification. GIS was also used to produce large-format color output maps. An interactive GIS program was written to provide on-line access to scanned photos taken at field sites. The pilot project found Landsat TM to be a credible source of land cover information for geologically young islands, and TM data bands are effective in detecting spectral characteristics of different land cover types through remote sensing. Large agriculture field patterns were resolved and mapped successfully from wildland vegetation, but small agriculture field patterns were not. Additional processing was required to work with the four TM scenes from two separate orbits which span three years, including El Nino and drought dates. Results of the project emphasized the need for further land cover and land use processing and research. Change in vegetation

  4. Detecting vegetation cover change on the summit of Cadillac Mountain using multi-temporal remote sensing datasets: 1979, 2001, and 2007.

    Science.gov (United States)

    Kim, Min-Kook; Daigle, John J

    2011-09-01

    This study examines the efficacy of management strategies implemented in 2000 to reduce visitor-induced vegetation impact and enhance vegetation recovery at the summit loop trail on Cadillac Mountain at Acadia National Park, Maine. Using single-spectral high-resolution remote sensing datasets captured in 1979, 2001, and 2007, pre-classification change detection analysis techniques were applied to measure fractional vegetation cover changes between the time periods. This popular sub-alpine summit with low-lying vegetation and attractive granite outcroppings experiences dispersed visitor use away from the designated trail, so three pre-defined spatial scales (small, 0-30 m; medium, 0-60 m; and large, 0-90 m) were examined in the vicinity of the summit loop trail with visitor use (experimental site) and a site chosen nearby in a relatively pristine undisturbed area (control site) with similar spatial scales. Results reveal significant changes in terms of rates of vegetation impact between 1979 and 2001 extending out to 90 m from the summit loop trail with no management at the site. No significant differences were detected among three spatial zones (inner, 0-30 m; middle, 30-60 m; and outer, 60-90 m) at the experimental site, but all were significantly higher rates of impact compared to similar spatial scales at the control site (all p vegetation impact and enhance vegetation recovery at the summit loop trail of Cadillac Mountain since 2000. However, the vegetation recovery has been rather minimal and did not reach the level of cover observed during the 1979 time period. In addition, the advantages and some limitations of using remote sensing technologies are discussed in detecting vegetation change in this setting and potential application to other recreation settings.

  5. Studies of land-cover, land-use, and biophysical properties of vegetation in the Large Scale Biosphere Atmosphere experiment in Amazonia.

    Science.gov (United States)

    Dar A. Robertsa; Michael Keller; Joao Vianei Soares

    2003-01-01

    We summarize early research on land-cover, land-use, and biophysical properties of vegetation from the Large Scale Biosphere Atmosphere (LBA) experiment in Amazoˆnia. LBA is an international research program developed to evaluate regional function and to determine how land-use and climate modify biological, chemical and physical processes there. Remote sensing has...

  6. Assessment of Land Use-Cover Changes and Successional Stages of Vegetation in the Natural Protected Area Altas Cumbres, Northeastern Mexico, Using Landsat Satellite Imagery

    Directory of Open Access Journals (Sweden)

    Uriel Jeshua Sánchez-Reyes

    2017-07-01

    Full Text Available Loss of vegetation cover is a major factor that endangers biodiversity. Therefore, the use of geographic information systems and the analysis of satellite images are important for monitoring these changes in Natural Protected Areas (NPAs. In northeastern Mexico, the Natural Protected Area Altas Cumbres (NPAAC represents a relevant floristic and faunistic patch on which the impact of loss of vegetation cover has not been assessed. This work aimed to analyze changes of land use and coverage (LULCC over the last 42 years on the interior and around the exterior of the area, and also to propose the time of succession for the most important types of vegetation. For the analysis, LANDSAT satellite images from 1973, 1986, 2000, 2005 and 2015 were used, they were classified in seven categories through a segmentation and maximum likelihood analysis. A cross-tabulation analysis was performed to determine the succession gradient. Towards the interior of the area, a significant reduction of tropical vegetation and, to a lesser extent, temperate forests was found, as well as an increase in scrub cover from 1973 to 2015. In addition, urban and vegetation-free areas, as well as modified vegetation, increased to the exterior. Towards the interior of the NPA, the processes of perturbation and recovery were mostly not linear, while in the exterior adjacent area, the presence of secondary vegetation with distinct definite time of succession was evident. The analysis carried out is the first contribution that evaluates LULCC in this important NPA of northeastern Mexico. Results suggest the need to evaluate the effects of these modifications on species.

  7. Representing the effects of alpine grassland vegetation cover on the simulation of soil thermal dynamics by ecosystem models applied to the Qinghai-Tibetan Plateau

    Science.gov (United States)

    Yi, S.; Li, N.; Xiang, B.; Wang, X.; Ye, B.; McGuire, A.D.

    2013-01-01

    Soil surface temperature is a critical boundary condition for the simulation of soil temperature by environmental models. It is influenced by atmospheric and soil conditions and by vegetation cover. In sophisticated land surface models, it is simulated iteratively by solving surface energy budget equations. In ecosystem, permafrost, and hydrology models, the consideration of soil surface temperature is generally simple. In this study, we developed a methodology for representing the effects of vegetation cover and atmospheric factors on the estimation of soil surface temperature for alpine grassland ecosystems on the Qinghai-Tibetan Plateau. Our approach integrated measurements from meteorological stations with simulations from a sophisticated land surface model to develop an equation set for estimating soil surface temperature. After implementing this equation set into an ecosystem model and evaluating the performance of the ecosystem model in simulating soil temperature at different depths in the soil profile, we applied the model to simulate interactions among vegetation cover, freeze-thaw cycles, and soil erosion to demonstrate potential applications made possible through the implementation of the methodology developed in this study. Results showed that (1) to properly estimate daily soil surface temperature, algorithms should use air temperature, downward solar radiation, and vegetation cover as independent variables; (2) the equation set developed in this study performed better than soil surface temperature algorithms used in other models; and (3) the ecosystem model performed well in simulating soil temperature throughout the soil profile using the equation set developed in this study. Our application of the model indicates that the representation in ecosystem models of the effects of vegetation cover on the simulation of soil thermal dynamics has the potential to substantially improve our understanding of the vulnerability of alpine grassland ecosystems to

  8. The influence of vegetation cover and soil physical properties on deflagration of shallow landslides - Nova Friburgo, RJ / Brazil

    Science.gov (United States)

    de Oliveira Marques, Maria Clara; Silva, Roberta; Fraga, Joana; Luiza Coelho Netto, Ana; Mululo Sato, Anderson

    2017-04-01

    In 2011, the mountainous region of the State of Rio de Janeiro (Brazil) suffered enormous social and economic losses due to thousands of landslides caused by an extreme rainfall event. The mapping of the scars of these landslides in an area of 421 km2 in the municipality of Nova Friburgo, RJ - Brazil resulted in a total of 3622, and 89% of these scars were located in areas covered by grasses and forests. Despite the unexpected result (64% of scars in forest areas), field evidence has shown that most of the forest fragments in the municipality are in the initial stages of succession and in different states of degradation, evidencing the need for a better understanding of the role of these forests in the detonation and propagation of landslides. Two slope forest areas with different ages (20 and 50 years) were evaluated in relation to the vegetative aspects that influence the stability of the slopes in each area. Hydrological monitoring, including precipitation, interception by manual and automatic method, soil moisture and subsurface flows were performed in two different areas: forest and grass. Soil moisture was monitored by granular matrix sensors and flows by collecting troughs in trenches at depths of 0 cm, 20 cm, 50 cm, 100 cm, 150 cm and 220 cm, which were also analyzed for biomass and length of thick roots (> 2 mm diameter) and thin roots (responsible for the higher subsurface flows found in the forest, that is, the greater aggregation of the soil, the existence of interconnected macropores, ducts and roots facilitate the transmission of water in depth. Associated with the high rainfall and high relative humidity, these vegetation favoured the formation of saturation zones and increased pore pressures of the water, causing landslides on lands between 0.5 m and 2.0 m. The results of hydraulic conductivity show that the difference (lateritic = 10-4 cm/s; saprolitic = 10-5 cm/s) between the layers of the soil can generate zones of hydraulic discontinuity in

  9. Vegetation cover change detection and assessment in arid environment using multi-temporal remote sensing images and ecosystem management approach

    Science.gov (United States)

    Abdelrahman Aly, Anwar; Mosa Al-Omran, Abdulrasoul; Shahwan Sallam, Abdulazeam; Al-Wabel, Mohammad Ibrahim; Shayaa Al-Shayaa, Mohammad

    2016-04-01

    Vegetation cover (VC) change detection is essential for a better understanding of the interactions and interrelationships between humans and their ecosystem. Remote sensing (RS) technology is one of the most beneficial tools to study spatial and temporal changes of VC. A case study has been conducted in the agro-ecosystem (AE) of Al-Kharj, in the center of Saudi Arabia. Characteristics and dynamics of total VC changes during a period of 26 years (1987-2013) were investigated. A multi-temporal set of images was processed using Landsat images from Landsat4 TM 1987, Landsat7 ETM+2000, and Landsat8 to investigate the drivers responsible for the total VC pattern and changes, which are linked to both natural and social processes. The analyses of the three satellite images concluded that the surface area of the total VC increased by 107.4 % between 1987 and 2000 and decreased by 27.5 % between years 2000 and 2013. The field study, review of secondary data, and community problem diagnosis using the participatory rural appraisal (PRA) method suggested that the drivers for this change are the deterioration and salinization of both soil and water resources. Ground truth data indicated that the deteriorated soils in the eastern part of the Al-Kharj AE are frequently subjected to sand dune encroachment, while the southwestern part is frequently subjected to soil and groundwater salinization. The groundwater in the western part of the ecosystem is highly saline, with a salinity ≥ 6 dS m-1. The ecosystem management approach applied in this study can be used to alike AE worldwide.

  10. Alterations in fruit and vegetable β-carotene and vitamin C content caused by open-sun drying, visqueen-covered and polyethylene-covered solar-dryers

    OpenAIRE

    Ndawula, J; Kabasa, JD; Byaruhanga, YB

    2004-01-01

    This study investigated the effects of three drying methods (open sun drying, visqueen-covered solar dryer and polyethylene-covered solar dryer) on b-carotene and vitamin C content of edible portions of mango fruit (Mangifera indica) and cowpea leaves (Vigna unguiculata). Commercial samples were analysed for vitamin C by titrimetry and b-carotene by spectrophotometery at 450nm. Differences in vitamin retention and loss associated with the three drying methods were assessed by analysis of vari...

  11. The dynamic vegetation cover change in Loess Plateau%黄土高原植被覆盖变化动态分析

    Institute of Scientific and Technical Information of China (English)

    刘咏梅; 李京忠; 夏露

    2011-01-01

    目的 对1998-2005年黄土高原植被覆盖变化进行分析.方法 以SPOT VEGETATION S10NDVI为数据源,以月NDVI最大值、NDVI年均值和NDVI变化率为指标,采用时间序列分析方法,阐明黄土高原植被覆盖的时空变化特征.结果 8年间,黄土高原的植被覆盖间或有降低,但植被活动总体呈现增强趋势.结论 植被覆盖变化趋势和气候紧密联系,中西部地区植被增加和减少的区域相互交错,这一特性是由农业生产活动、城市建设、政府决策以及植被对气候变化的响应等综合因素作用的结果.%Aim Analysis on the dynamic vegetation cover change in Loess Plateau from 1998 to 2005. Methods Dynamic changes in Loess Plateau vegetation over 8 years and their spatial patterns were explored, using maximum NDVI per month, mean NDVI per year and NDVI deviation derived from SPOT VEGETATION S10 NDVI as indexes and adopting time-series analysis approach. Results Although significant declines appeared from 1998 to 2001 and from 2004 to 2005, an increasing trend occurred over the past eight years. Conclusion The dynamic vegetation cover is closely coupled with climatic fluctuation, vegetation increased areas and decreased areas are intervened mutually in middle of Loess Plateau, which is caused by agricultural activities, city construction, government policies and the response of vegetation to climate changes.

  12. 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.

  13. Does the spatial arrangement of vegetation and anthropogenic land cover features matter? Case studies of urban warming and cooling in Phoenix and Las Vegas

    Science.gov (United States)

    Myint, S. W.; Zheng, B.; Fan, C.; Kaplan, S.; Brazel, A.; Middel, A.; Smith, M.

    2014-12-01

    While the relationship between fractional cover of anthropogenic and vegetation features and the urban heat island has been well studied, the effect of spatial arrangements (e.g., clustered, dispersed) of these features on urban warming or cooling are not well understood. The goal of this study is to examine if and how spatial configuration of land cover features influence land surface temperatures (LST) in urban areas. This study focuses on Phoenix, AZ and Las Vegas, NV that have undergone dramatic urban expansion. The data used to classify detailed urban land cover types include Geoeye-1 (Las Vegas) and QuickBird (Phoenix). The Geoeye-1 image (3 m resolution) was acquired on October 12, 2011 and the QuickBird image (2.4 m resolution) was taken on May 29, 2007. Classification was performed using object based image analysis (OBIA). We employed a spatial autocorrelation approach (i.e., Moran's I) that measures the spatial dependence of a point to its neighboring points and describes how clustered or dispersed points are arranged in space. We used Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data acquired over Phoenix (daytime on June 10, 2011 and nighttime on October 17, 2011) and Las Vegas (daytime on July 6, 2005 and nighttime on August 27, 2005) to examine daytime and nighttime LST with regards to the spatial arrangement of anthropogenic and vegetation features. We spatially correlate Moran's I values of each land cover per surface temperature, and develop regression models. The spatial configuration of grass and trees shows strong negative correlations with LST, implying that clustered vegetation lowers surface temperatures more effectively. In contrast, a clustered spatial arrangement of anthropogenic land-cover features, especially impervious surfaces, significantly elevates surface temperatures. Results from this study suggest that the spatial configuration of anthropogenic and vegetation features influence urban warming and cooling.

  14. Analysis of Spatial-Temporal Variation of Land Surface Temperature, Vegetation and Snow Cover in Lar National Park of Iran

    Science.gov (United States)

    Arekhi, M.

    2016-10-01

    Changes in land surface reflectance measured by remote sensing data can be useful in climate change studies. This study attempts to analyze the spatial-temporal extent change of vegetation greenness, Land Surface Temperature (LST), and Normalized Difference Snow Index (NDSI) in late spring at the Lar National Park of Iran using Landsat data. Vegetation indices (VIs), LST, and NDSI maps were calculated for each date (1985, 1994, 2010, and 2015). All VIs have shown an increasing trend from 1985 to 2015 which depicted increase of vegetation. Spectral reflectance of all bands is declining from 1985 to 2015 except in near-infrared (NIR) bands. High reflectance in NIR bands is due to increased vegetation greenness. The reduction was seen in the visible bands that show increased vegetation photosynthetic activity. In the short-wave infrared bands (SWIR) were observed reduced trend from 1985 to 2015 which is indicate increased vegetation. Also, in the mid-wave infrared (MWIR) bands were observed a declining trend which is the result of decreasing soil fraction from 1985 to 2015. LST has increased from 23.27 °C in 1985 to 27.45 °C in 2015. Snow patches were decreased over the study period. In conclusion, VIs and surface reflectance bands are considered the main tool to display vegetation change. Also, high VIs values showed healthy and dense vegetation. The results of our study will provide valuable information in preliminary climate change studies.

  15. ANALYSIS OF SPATIAL-TEMPORAL VARIATION OF LAND SURFACE TEMPERATURE, VEGETATION AND SNOW COVER IN LAR NATIONAL PARK OF IRAN

    Directory of Open Access Journals (Sweden)

    M. Arekhi

    2016-10-01

    Full Text Available Changes in land surface reflectance measured by remote sensing data can be useful in climate change studies. This study attempts to analyze the spatial-temporal extent change of vegetation greenness, Land Surface Temperature (LST, and Normalized Difference Snow Index (NDSI in late spring at the Lar National Park of Iran using Landsat data. Vegetation indices (VIs, LST, and NDSI maps were calculated for each date (1985, 1994, 2010, and 2015. All VIs have shown an increasing trend from 1985 to 2015 which depicted increase of vegetation. Spectral reflectance of all bands is declining from 1985 to 2015 except in near-infrared (NIR bands. High reflectance in NIR bands is due to increased vegetation greenness. The reduction was seen in the visible bands that show increased vegetation photosynthetic activity. In the short-wave infrared bands (SWIR were observed reduced trend from 1985 to 2015 which is indicate increased vegetation. Also, in the mid-wave infrared (MWIR bands were observed a declining trend which is the result of decreasing soil fraction from 1985 to 2015. LST has increased from 23.27 °C in 1985 to 27.45 °C in 2015. Snow patches were decreased over the study period. In conclusion, VIs and surface reflectance bands are considered the main tool to display vegetation change. Also, high VIs values showed healthy and dense vegetation. The results of our study will provide valuable information in preliminary climate change studies.

  16. From local spectral measurements to maps of vegetation cover and biomass on the Qinghai-Tibet-Plateau: Do we need hyperspectral information?

    Science.gov (United States)

    Meyer, Hanna; Lehnert, Lukas W.; Wang, Yun; Reudenbach, Christoph; Nauss, Thomas; Bendix, Jörg

    2017-03-01

    Though the relevance of pasture degradation on the Qinghai-Tibet Plateau (QTP) is widely postulated, its extent is still unknown. Due to the enormous spatial extent, remote sensing provides the only possibility to investigate pasture degradation via frequently used proxies such as vegetation cover and aboveground biomass (AGB). However, unified remote sensing approaches are still lacking. This study tests the applicability of hyper- and multispectral in situ measurements to map vegetation cover and AGB on regional scales. Using machine learning techniques, it is tested whether the full hyperspectral information is needed or if multispectral information is sufficient to accurately estimate pasture degradation proxies. To regionalize pasture degradation proxies, the transferability of the locally derived ML-models to high resolution multispectral satellite data is assessed. 1183 hyperspectral measurements and vegetation records were performed at 18 locations on the QTP. Random Forests models with recursive feature selection were trained to estimate vegetation cover and AGB using narrow-band indices (NBI) as predictors. Separate models were calculated using NBI from hyperspectral data as well as from the same data resampled to WorldView-2, QuickBird and RapidEye channels. The hyperspectral results were compared to the multispectral results. Finally, the models were applied to satellite data to map vegetation cover and AGB on a regional scale. Vegetation cover was accurately predicted by Random Forest if hyperspectral measurements were used (cross validated R2 = 0.89). In contrast, errors in AGB estimations were considerably higher (cross validated R2 = 0.32). Only small differences in accuracy were observed between the models based on hyperspectral compared to multispectral data. The application of the models to satellite images generally resulted in an increase of the estimation error. Though this reflects the challenge of applying in situ measurements to satellite

  17. Development of a Decision Support Tree Approach for Mapping Urban Vegetation Cover From Hyperspectral Imagery and GIS: the case of Athens, Greece

    Science.gov (United States)

    Georgopoulou, Iro; Petropoulos, George P.; Kalivas, Dionissios P.

    2013-04-01

    Urban vegetation represents one of the main factors directly influencing human life. Consequently, extracting information on its spatial distribution is of crucial importance to ensure, between other, sustainable urban planning and successful environmental management. To this end, remote sensing & Geographical Information Systems (GIS) technology has demonstrated a very promising, viable solution. In comparison to multispectral systems, use of hyperspectral imagery in particular, enhances dramatically our ability to accurately identify different targets on the Earth's surface. In our study, a decision tree-based classification method is presented for mapping urban vegetation cover from hyperspectral imagery. The ability of the proposed method is demonstrated using as a case study the city of Athens, Greece, for which satellite hyperspectral imagery from Hyperion sensor has been acquired. Hyperion collects spectral data in 242 spectral bands from visible to middle-infrared regions of electromagnetic spectrum and at a spatial resolution of 30 meters. Validation of our proposed method is carried out on a GIS environment based on the error matrix statistics, using as reference very high resolution imagery acquired nearly concurrently to Hyperion at our study region, supported by field visits conducted in the studied area. Additionally, the urban vegetation cover maps derived from our proposed here technique are compared versus analogous results obtained against other classification methods traditionally used in mapping urban vegetation cover. Our results confirmed the ability of our approach combined with Hyperion imagery to extract urban vegetation cover for the case of a densely-populated city with complex urban features, such as Athens. Our findings can potentially offer significant information at local scale as regards the presence of open green spaces in urban environment, since such information is vital for the successful infrastructure development, urban

  18. Using high resolution imagery to detect woody vegetation and land-cover change over 50 years in the Sahel of Mali

    Science.gov (United States)

    Spiekermann, Raphael; Brandt, Martin; Samimi, Cyrus

    2013-04-01

    The Sahel region has been acclaimed as one of the "hot spots" of global environmental change in the last decades. The degradation of the environmental conditions was accelerated by prolonged droughts in the region during the 1970s and 1980s and an overall decrease in annual precipitation. The resulting loss of woody vegetation cover was often considered as irreversible desertification. Recent findings, based on small-scaled analyses of satellite images, show an increase of vegetation greenness over most parts of the Sahel since the mid-1980s. However, due to a lack of detailed regional studies, it remains largely unclear if this is a return to pre-drought conditions or a transformation of land cover to a new equilibrium state. This study intends to use remote sensing techniques, supplemented by ground truth data to compare the pre-drought woody vegetation and land cover with the current situation. High resolution panchromatic Corona imagery of 1967 and multispectral RapidEye imagery of 2011 form the basis of this regional scaled study, which includes parts of the Dogon Plateau and the Seno Plains in the Sahel of Mali. The feature extraction and classification operations included in ERDAS Imagine Objective are used in an object-oriented approach in combination with spectral properties to analyse the datasets and map millions of individual trees and large shrubs. Results indicate number of trees per hectare as well as woody vegetation coverage in percent per hectare for both 1967 and 2011. Additionally, the land-cover change during the past half century is assessed followed by an analysis of current and past woody vegetation densities in relation to land-cover classes. Results show a significant increase of cultivated land, in particular in the Seno Plains, a reduction of dense natural woody vegetation as well as an increase of trees on farmer's fields on the Dogon Plateau. Our results show that neither the desertification paradigm nor the greening paradigm can be

  19. Spatial relationship between climatologies and changes in global vegetation activity

    NARCIS (Netherlands)

    Jong, de R.; Schaepman, M.E.; Furrer, R.; Bruin, de S.; Verburg, P.H.

    2013-01-01

    Vegetation forms a main component of the terrestrial biosphere and plays a crucial role in land-cover and climate-related studies. Activity of vegetation systems is commonly quantified using remotely sensed vegetation indices (VI). Extensive reports on temporal trends over the past decades in time s

  20. Relating stable isotope and geochemical data to conclude on water residence times in four small alpine headwater catchments with differing vegetation cover

    Directory of Open Access Journals (Sweden)

    M. H. Mueller

    2012-09-01

    Full Text Available The mean water residence time (MRT in a catchment gives information about storage, flow pathways, sources of water and thus also about retention and release of solutes in a catchment. To our knowledge there are no catchment studies on the influence of vegetation cover change on base flow mean water residence times. The main changes in vegetation cover in the Swiss Alps are massive shrub encroachment and forest expansion into formerly open habitats. Four small and relatively steep catchments in the Swiss Alps (Ursern valley were investigated to relate different vegetation cover to water residence times and geochemical behaviour of runoff.

    Time series of water stable isotopes were used to calculate mean water residence times. The high temporal variation of the stable isotope signals in precipitation was strongly dampened in stream base flow samples. Mean water residence times of the four catchments were 64–98 weeks. The strong dampening of our input signal might point to deeper flow paths and mixing of waters of different ages at the catchments outlets. Parent geological materials are mainly gneisses and schists but they can contain dolomite, carbonate or gypsum rich zones. The major part of the quickly infiltrating precipitation likely percolates through these deeper zones. Relatively high stream water pH, Ca and SO42− concentrations in micro catchment outlets support this conclusion.

    We conclude that in mountainous headwater catchments with relatively thin soil layers the geological and topographical situation and snow dynamics influence storage, mixing and release of meteoric waters and its geochemistry in a stronger way than vegetation cover or catchment size do.

  1. Influence of vegetation structure on lidar-derived canopy height and fractional cover in forested riparian buffers during leaf-off and leaf-on conditions.

    Science.gov (United States)

    Wasser, Leah; Day, Rick; Chasmer, Laura; Taylor, Alan

    2013-01-01

    Estimates of canopy height (H) and fractional canopy cover (FC) derived from lidar data collected during leaf-on and leaf-off conditions are compared with field measurements from 80 forested riparian buffer plots. The purpose is to determine if existing lidar data flown in leaf-off conditions for applications such as terrain mapping can effectively estimate forested riparian buffer H and FC within a range of riparian vegetation types. Results illustrate that: 1) leaf-off and leaf-on lidar percentile estimates are similar to measured heights in all plots except those dominated by deciduous compound-leaved trees where lidar underestimates H during leaf off periods; 2) canopy height models (CHMs) underestimate H by a larger margin compared to percentile methods and are influenced by vegetation type (conifer needle, deciduous simple leaf or deciduous compound leaf) and canopy height variability, 3) lidar estimates of FC are within 10% of plot measurements during leaf-on periods, but are underestimated during leaf-off periods except in mixed and conifer plots; and 4) depth of laser pulse penetration lower in the canopy is more variable compared to top of the canopy penetration which may influence within canopy vegetation structure estimates. This study demonstrates that leaf-off lidar data can be used to estimate forested riparian buffer canopy height within diverse vegetation conditions and fractional canopy cover within mixed and conifer forests when leaf-on lidar data are not available.

  2. Soil erosion and its correlation with vegetation cover: An assesment using multispectral imagery and pixel-based geographic information system in Gesing Sub-Watershed, Central Java, Indonesia

    Science.gov (United States)

    Dirda Gupita, Diwyacitta; Sigit Heru Murti, B. S.

    2017-01-01

    Soil erosion in caused by five factors: rainfall erosivity, soil erodibility, slope and slope length, crop management, and land conservation practices. In theory, vegetation as one of the affecting factors has inversed correlation with soil erosion. This research is aimed to: (1) model RUSLE using pixel-based GIS, and (2) prove whether or not vegetation really has the said correlation with the soil erosion that occurs in Gesing Watershed. The method used in this research is divided into two: the use of RUSLE to estimate the soil erosion rate; and the use of fractional vegetation cover (FVC) formula to estimate the vegetation density in the area. Both methods used Landsat-8 OLI imagery, which is used to extract the RUSLE parameters as well as to derive the vegetation density through NDVI, and pixel-based GIS. The mapping of soil erosion rate distribution done in this research demonstrated that pixel-based modeling is able to represent a much more detailed and logical distribution of a phenomenon. The distribution of soil erosion rate in Gesing Watershed showed that the erosion rate in this area is relatively minor. About 1425.99 hectares and 1587.57 hectares of the total area have erosion rate of 0 – 15 tons/ha/yr (very mild) and 15 – 60 tons/ha/yr (mild) respectively.

  3. VEGETATION ANALYSIS AND LAND USE LAND COVER CLASSIFICATION OF FOREST IN UTTARA KANNADA DISTRICT INDIA USING REMOTE SENSIGN AND GIS TECHNIQUES

    Directory of Open Access Journals (Sweden)

    A. G. Koppad

    2017-10-01

    Full Text Available The study was conducted in Uttara Kannada districts during the year 2012–2014. The study area lies between 13.92° N to 15.52° N latitude and 74.08° E to 75.09° E longitude with an area of 10,215 km2. The Indian satellite IRS P6 LISS-III imageries were used to classify the land use land cover classes with ground truth data collected with GPS through supervised classification in ERDAS software. The land use and land cover classes identified were dense forest, horticulture plantation, sparse forest, forest plantation, open land and agriculture land. The dense forest covered an area of 63.32 % (6468.70 sq km followed by agriculture 12.88 % (1315.31 sq. km, sparse forest 10.59 % (1081.37 sq. km, open land 6.09 % (622.37 sq. km, horticulture plantation and least was forest plantation (1.07 %. Settlement, stony land and water body together cover about 4.26 percent of the area. The study indicated that the aspect and altitude influenced the forest types and vegetation pattern. The NDVI map was prepared which indicated that healthy vegetation is represented by high NDVI values between 0.1 and 1. The non- vegetated features such as water bodies, settlement, and stony land indicated less than 0.1 values. The decrease in forest area in some places was due to anthropogenic activities. The thematic map of land use land cover classes was prepared using Arc GIS Software.

  4. How To Assess The Future Tree-Cover Potential For Reforestation Planning In Semi-Arid Regions? An Attempt Using The Vegetation Model ORCHIDEE

    Science.gov (United States)

    Rajaud, A.; De Noblet-Ducoudré, N.

    2015-12-01

    More and more reforestation projects are undertaken at local to continental scales to fight desertification, to address development challenges, and to improve local living conditions in tropical semi-arid regions. These regions are very sensitive to climatic changes and the potential for maintaining tree-covers will be altered in the next decades. Therefore, reforestation planning needs predicting the future "climatic tree-cover potential": the optimum tree-fraction sustainable in future climatic states. Global circulation models projections provide possible future climatologies for the 21st century. These can be used at the global scale to force a land-surface model, which in turn simulates the vegetation development under these conditions. The tree cover leading to an optimum development may then be identified. We propose here to run a state-of-the-art model and to assess the span and the relevance of the answers that can be obtained for reforestation planning. The ORCHIDEE vegetation model is chosen here to allow a multi-criteria evaluation of the optimum cover, as it returns surface climate state variables as well as vegetation functioning and biomass products. It is forced with global climate data (WFDEI and CRU) for the 20th century and models projections (CMIP5 outputs) for the 21st century. At the grid-cell resolution of the forcing climate data, tree-covers ranging from 0 to 100% are successively prescribed. A set of indicators is then derived from the model outputs, meant for modulating reforestation strategies according to the regional priorities (e.g. maximize the biomass production or decrease the surface air temperature). The choice of indicators and the relevance of the final answers provided will be collectively assessed by the climate scientists and reforestation project management experts from the KINOME social enterprise (http://en.kinome.fr). Such feedback will point towards the model most urging needs for improvement.

  5. On the Role of Urban and Vegetative Land Cover in the Identification of Tornado Damage Using Dual-Resolution Multispectral Satellite Imagery

    Science.gov (United States)

    Kingfield, D.; de Beurs, K.

    2014-12-01

    It has been demonstrated through various case studies that multispectral satellite imagery can be utilized in the identification of damage caused by a tornado through the change detection process. This process involves the difference in returned surface reflectance between two images and is often summarized through a variety of ratio-based vegetation indices (VIs). Land cover type plays a large contributing role in the change detection process as the reflectance properties of vegetation can vary based on several factors (e.g. species, greenness, density). Consequently, this provides the possibility for a variable magnitude of loss, making certain land cover regimes less reliable in the damage identification process. Furthermore, the tradeoff between sensor resolution and orbital return period may also play a role in the ability to detect catastrophic loss. Moderate resolution imagery (e.g. Moderate Resolution Imaging Spectroradiometer (MODIS)) provides relatively coarse surface detail with a higher update rate which could hinder the identification of small regions that underwent a dynamic change. Alternatively, imagery with higher spatial resolution (e.g. Landsat) have a longer temporal return period between successive images which could result in natural recovery underestimating the absolute magnitude of damage incurred. This study evaluates the role of land cover type and sensor resolution on four high-end (EF3+) tornado events occurring in four different land cover groups (agriculture, forest, grassland, urban) in the spring season. The closest successive clear images from both Landsat 5 and MODIS are quality controlled for each case. Transacts of surface reflectance across a homogenous land cover type both inside and outside the damage swath are extracted. These metrics are synthesized through the calculation of six different VIs to rank the calculated change metrics by land cover type, sensor resolution and VI.

  6. Stimulation of methane oxidation potential and effects on vegetation growth by bottom ash addition in a landfill final evapotranspiration cover

    NARCIS (Netherlands)

    Kim, G.W.; Ho, A.; Kim, P.J.; Kim, Sang Yun

    2016-01-01

    The landfilling of municipal solid waste is a significant source of atmospheric methane (CH4), contributing up to 20% of total anthropogenic CH4 emissions. The evapotranspiration (ET) cover system, an alternative final cover system in waste landfills, has been considered to be a promising way to mit

  7. Stimulation of methane oxidation potential and effects on vegetation growth by bottom ash addition in a landfill final evapotranspiration cover

    NARCIS (Netherlands)

    Kim, G.W.; Ho, A.; Kim, P.J.; Kim, Sang Yun

    2016-01-01

    The landfilling of municipal solid waste is a significant source of atmospheric methane (CH4), contributing up to 20% of total anthropogenic CH4 emissions. The evapotranspiration (ET) cover system, an alternative final cover system in waste landfills, has been considered to be a promising way to

  8. Stimulation of methane oxidation potential and effects on vegetation growth by bottom ash addition in a landfill final evapotranspiration cover

    NARCIS (Netherlands)

    Kim, G.W.; Ho, A.; Kim, P.J.; Kim, Sang Yun

    2016-01-01

    The landfilling of municipal solid waste is a significant source of atmospheric methane (CH4), contributing up to 20% of total anthropogenic CH4 emissions. The evapotranspiration (ET) cover system, an alternative final cover system in waste landfills, has been considered to be a promising way to mit

  9. Plant growth on debris covered glacier surfaces - ecology, vegetation patterns and implications for debris mantled glaciers serving as cold and warm stage plant refugia in the past

    Science.gov (United States)

    Fickert, Thomas; Friend, Donald; Grüninger, Friederike; Molnia, Bruce; Richter, Michael

    2017-04-01

    As stated at the International Conference on Debris-Covered Glaciers in 2000, "debris-covered glaciers comprise a significant fraction of the global population of glaciers...." Given a minimum of debris thickness and sufficient stability, these surfaces host surprisingly diverse plant assemblages, both floristically and structurally. Observations of plant growth on glacier surfaces are reported from around the world - including mature forests with trees more than 50cm in diameter. Debris covered glacier surfaces are mobile habitats for plants, which migrate downhill with glacier movement, but are able to spread upward with strong anabatic valley winds. Plant growth is possible even on a very shallow debris cover. Depending on site conditions, floristic composition and structure of vegetation on debris covered glaciers represent a mosaic of environments, including subnival pioneer communities, glacier foreland early- to late-successional stages, and morainal locations. The taxa involved display a wide spectrum of adaptations to habitat conditions with particular migration and dispersal strategies. With a shallow debris cover, alpine/subnival taxa can grow considerably below their usual altitudinal niche due to the cooler subsurface soil temperatures. In contrast, a greater thickness of debris cover allows even thermophilous plants of lower elevations to grow on glacier surfaces. Employing the principle of actualism, debris covered glaciers provided important and previously undocumented refugia for plants during the Pleistocene cold stages from which alpine and arctic plant species were able to re-establish and spread in post-glacial time. This assumption is complementary to the two competing ideas to explain the fate of alpine and/or arctic taxa during the Pleistocene, the nunatak hypothesis (i.e. in-situ survival of plants on unglaciated summits) and tabula rasa theory (i.e. displacement of plants and subsequent remigration). Vice versa debris covered glaciers

  10. Evidence of extensive reef development and high coral cover in nearshore environments: implications for understanding coral adaptation in turbid settings

    Science.gov (United States)

    Morgan, Kyle M.; Perry, Chris T.; Smithers, Scott G.; Johnson, Jamie A.; Daniell, James J.

    2016-07-01

    Mean coral cover has reportedly declined by over 15% during the last 30 years across the central Great Barrier Reef (GBR). Here, we present new data that documents widespread reef development within the more poorly studied turbid nearshore areas (30 m) mesophotic equivalents and may have similar potential as refugia from large-scale disturbances.

  11. Belowground eco-restoration of a suburban waste-storage landscape: Earthworm dynamics in grassland and in a succession of woody vegetation covers.

    Science.gov (United States)

    Morales, Pamela K; Yunusa, Isa A M; Lugg, Glenys; Li, Zheng; Gribben, Paul; Eamus, Derek

    2013-12-01

    Restoration of belowground ecology is seldom a priority in designing revegetation strategies for disturbed landscapes. We determined earthworm abundance and diversity in a 16-year old grass sward (grassland), a 6-year old (Plantation-04) and a 4-year old (Plantation-06) plantation, both of mixed woody species, on a reclaimed waste disposal site, and in nearby remnant woodland, in suburban Sydney, Australia. While no catches were made in autumn, more earthworms were found in spring (21 ± 8.6 m(-2)) than in winter (10.2 ± 5.9 m(-2)) or summer (14.4 ± 5.5 m(-2)). Earthworm abundance in spring was in the order grassland ≈ Plantation-04 (35.2 m(-2)) > woodland (12.8 m(-2)) > Plantation-06 (0.8 m(-2)). None of the revegetated covers had restored earthworm diversity to levels found in the woodland. Exotic species, mostly Microscolex dubius, dominated in the four vegetation covers at any time; the only two native species (Heteroporodrilus sp. and Megascoleceides sp.) found were in the woodland. We also assessed how quality of the evolving soils from the three revegetated covers, compared with that from the woodland, impacted viability of common exotic earthworm species. Both weight gain and cocoon production by the exotic earthworms were higher in the soil from Plantation-04 than in soils from the other vegetation covers, including the woodland; the two variables were positively correlated with the pH and mineral nutrient content (as indicated by electrical conductivity that was in turn correlated with clay content) of the soil. Age of vegetation rather than its composition explained differences in the level of earthworm recovery observed.

  12. The influence of soil type, vegetation cover and soil moisture on spin up behaviour of a land surface model in a monsoonal region

    Science.gov (United States)

    Bhattacharya, Anwesha; Mandal, Manabottam

    2015-04-01

    Model spin-up is the process through which the model is adequately equilibrated to ensure balance between the mass fields and velocity fields. In this study, an offline one dimensional Noah land surface model is integrated recursively for three years to assess its spin-up behavior at different sites over the Indian Monsoon domain. Several numerical experiments are performed to investigate the impact of soil category, vegetation cover, initial soil moisture and subsequent dry or wet condition on model spin-up. These include simulations with the dominant soil and vegetation covers of this region, different initial soil moisture content (observed soil moisture; dry soil; moderately wet soil; saturated soil), simulations initialized at different rain conditions (no rain; infrequent rain; continuous rain) and different seasons (Winter, Spring, Summer/Pre-Monsoon, Monsoon and Autumn). It is seen that the spin-up behavior of the model depends on the soil type and vegetation cover with soil characteristics having the larger influence. Over India, the model has the longest spin-up in the case of simulations with loamy soil covered with mixed-shrub. It is noted that the model has a significantly longer spin-up when initialized with very low initial soil moisture content than with higher soil moisture content. It is also seen that in general, simulations initialized just before a continuous rainfall event have the least spin-up time. This observation is reinforced by the results from the simulations initialized in different seasons. It is seen that for monsoonal region, the model spin-up time is least for simulations initialized just before the Monsoon. Model initialized during the Monsoon rain episodes has a longer spin-up than that initialized in any other season. Furthermore, it is seen that the model has a shorter spin-up if it reaches the equilibrium state predominantly via drying process and could be as low as two months under quasi-equilibrium condition depending on

  13. 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

  14. Soil macroinvertebrates' abundance and diversity in home gardens in Tabasco, Mexico, vary with soil texture, organic matter and vegetation cover

    NARCIS (Netherlands)

    Huerta, E.; Wal, van der J.C.

    2012-01-01

    We studied the composition of soil invertebrate communities and vegetation in 50 home gardens in the humid tropical lowlands of Tabasco, Mexico, located in five geomorphological regions. Five monoliths were made in each home garden and soil invertebrates were hand sorted, weighed and classified to m

  15. Computer implemented land cover classification using LANDSAT MSS digital data: A cooperative research project between the National Park Service and NASA. 3: Vegetation and other land cover analysis of Shenandoah National Park

    Science.gov (United States)

    Cibula, W. G.

    1981-01-01

    Four LANDSAT frames, each corresponding to one of the four seasons were spectrally classified and processed using NASA-developed computer programs. One data set was selected or two or more data sets were marged to improve surface cover classifications. Selected areas representing each spectral class were chosen and transferred to USGS 1:62,500 topographic maps for field use. Ground truth data were gathered to verify the accuracy of the classifications. Acreages were computed for each of the land cover types. The application of elevational data to seasonal LANDSAT frames resulted in the separation of high elevation meadows (both with and without recently emergent perennial vegetation) as well as areas in oak forests which have an evergreen understory as opposed to other areas which do not.

  16. Using lidar data to analyse sinkhole characteristics relevant for understory vegetation under forest cover-case study of a high karst area in the dinaric mountains.

    Science.gov (United States)

    Kobal, Milan; Bertoncelj, Irena; Pirotti, Francesco; Dakskobler, Igor; Kutnar, Lado

    2015-01-01

    In this article, we investigate the potential for detection and characterization of sinkholes under dense forest cover by using airborne laser scanning data. Laser pulse returns from the ground provide important data for the estimation of digital elevation model (DEM), which can be used for further processing. The main objectives of this study were to map and determine the geomorphometric characteristics of a large number of sinkholes and to investigate the correlations between geomorphology and vegetation in areas with such characteristics. The selected study area has very low anthropogenic influences and is particularly suitable for studying undisturbed karst sinkholes. The information extracted from this study regarding the shapes and depths of sinkholes show significant directionality for both orientation of sinkholes and their distribution over the area. Furthermore, significant differences in vegetation diversity and composition occur inside and outside the sinkholes, which indicates their presence has important ecological impacts.

  17. Using lidar data to analyse sinkhole characteristics relevant for understory vegetation under forest cover-case study of a high karst area in the dinaric mountains.

    Directory of Open Access Journals (Sweden)

    Milan Kobal

    Full Text Available In this article, we investigate the potential for detection and characterization of sinkholes under dense forest cover by using airborne laser scanning data. Laser pulse returns from the ground provide important data for the estimation of digital elevation model (DEM, which can be used for further processing. The main objectives of this study were to map and determine the geomorphometric characteristics of a large number of sinkholes and to investigate the correlations between geomorphology and vegetation in areas with such characteristics. The selected study area has very low anthropogenic influences and is particularly suitable for studying undisturbed karst sinkholes. The information extracted from this study regarding the shapes and depths of sinkholes show significant directionality for both orientation of sinkholes and their distribution over the area. Furthermore, significant differences in vegetation diversity and composition occur inside and outside the sinkholes, which indicates their presence has important ecological impacts.

  18. Woody vegetation cover monitoring with multi-temporal Landsat data and Random Forests: the case of the Northwest Province (South Africa)

    Science.gov (United States)

    Symeonakis, Elias; Higginbottom, Thomas; Petroulaki, Kyriaki

    2016-04-01

    Land degradation and desertification (LDD) are serious global threats to humans and the environment. Globally, 10-20% of drylands and 24% of the world's productive lands are potentially degraded, which affects 1.5 billion people and reduces GDP by €3.4 billion. In Africa, LDD processes affect up to a third of savannahs, leading to a decline in the ecosystem services provided to some of the continent's poorest and most vulnerable communities. Indirectly, LDD can be monitored using relevant indicators. The encroachment of woody plants into grasslands, and the subsequent conversion of savannahs and open woodlands into shrublands, has attracted a lot of attention over the last decades and has been identified as an indicator of LDD. According to some assessments, bush encroachment has rendered 1.1 million ha of South African savanna unusable, threatens another 27 million ha (~17% of the country), and has reduced the grazing capacity throughout the region by up to 50%. Mapping woody cover encroachment over large areas can only be effectively achieved using remote sensing data and techniques. The longest continuously operating Earth-observation program, the Landsat series, is now freely-available as an atmospherically corrected, cloud masked surface reflectance product. The availability and length of the Landsat archive is thus an unparalleled Earth-observation resource, particularly for long-term change detection and monitoring. Here, we map and monitor woody vegetation cover in the Northwest Province of South Africa, a mosaic of 12 Landsat scenes that expands over more than 100,000km2. We employ a multi-temporal approach with dry-season TM, ETM+ and OLI data from 15 epochs between 1989 to 2015. We use 0.5m-pixel colour aerial photography to collect >15,000 samples for training and validating a Random Forest model to map woody cover, grasses, crops, urban and bare areas. High classification accuracies are achieved, especially so for the two cover types indirectly

  19. Changes in vegetative cover on Western Arctic Herd winter range from 1981 to 2005: potential effects of grazing and climate change

    Directory of Open Access Journals (Sweden)

    Kyle Joly

    2007-04-01

    Full Text Available The population of the Western Arctic Herd, estimated at 490 000 caribou (Rangifer tarandus granti in 2003, is at its highest level in 30 years. Twenty permanent range transects were established in the winter range of the Western Arctic Herd in 1981 to assess the impacts of grazing. These transects were revisited in 1995 and 1996 (1995/96. Only 18 of the transects were re-located, so an additional 7 transects were established in 1996. In 2005, all 25 remaining transects were revisited. Lichen coverage dropped by a relative 45.1% between 1981 and 1995/96 and by an additional relative 25.6% between 1995/96 and 2005. There was a significant decline in primary forage lichens between 1995/96 and 2005. Caribou use was greater in areas with high lichen abundance. Graminoid cover increased by a relative 118.4% from 1981 to 1995/96 and again by a relative 26.1% from 1995/96 to 2005. Shrub cover increased during the study whereas forb cover declined. The decline in lichen abundance on the winter range of the Western Arctic Herd over 24 years is an index of caribou habitat condition. The observed changes in vegetation cover can be attributed to caribou grazing, fire, and possibly global climate change. Continued declines in lichen cover could lead to population declines within the herd, range shifts, or both.

  20. Índice de cobertura vegetal e sua modelagem para cultivares de soja no sul de Minas Gerais Index of vegetal cover and its modeling for soybean cultivars in the south of Minas Gerais

    Directory of Open Access Journals (Sweden)

    Vitor Corrêa de Mattos Barreto

    2010-10-01

    Full Text Available A cobertura vegetal do solo é decisiva para redução dos efeitos erosivos do impacto direto das gotas de chuva na superfície do solo. Desta forma, objetivou-se com este estudo determinar o índice de cobertura vegetal (CV e desenvolver modelos para sua estimativa para a cultura da soja, usando os atributos climáticos no período de chuvas intensas no Sul de Minas Gerais. As determinações da CV foram feitas semanalmente, na área experimental do Departamento de Ciência do Solo, Universidade Federal de Lavras, no período de novembro de 1999 a maio de 2000, em 28 cultivares de soja com potencial para cultivo nesta região. Para avaliação da cobertura vegetal foi utilizada a metodologia descrita por Stocking (1988. Na modelagem procurou-se relacionar a CV com os valores acumulados dos seguintes atributos climáticos: temperatura média (Tmed, precipitação (PREC e umidade relativa do ar (UR. Os valores de cobertura vegetal apresentaram uma amplitude de variação de 56 a 83%, sendo BR 162, LO 12 L e M. Soy 108 as cultivares mais eficientes e FT Abyara e Tucano as menos eficientes. O hábito diferencial de crescimento das cultivares ajuda a explicar esse comportamento. O modelo ajustado adequado para estimativa da CV foi: CV = 116589,976 + 0,422 . Tmed + 0,132 . PREC - 0,095 . UR + 0,000024 . Tmed², R² = 0,99 (P Vegetal cover of soil is decisive to reduce the erosive effects of direct impact of raindrops on the soil surface. Therefore, the objective of this study was to determine the vegetal cover (CC index and to develop models to estimate it for soybean cultivars, using climatic attributes in the period of intense rains in the South of the State of Minas Gerais in Brazil. CC was measured weekly in the experimental area of the Department of Soil Science, Federal University of Lavras, from November 1999 to May 2000, for 28 soybean cultivars with yield potential in this region. To evaluate the vegetal cover, the method described by

  1. Numerical study of the impact of vegetation coverings on sound levels and time decays in a canyon street model.

    Science.gov (United States)

    Guillaume, G; Gauvreau, B; L'Hermite, P

    2015-01-01

    Given a constantly increasing urban population, the mitigation of environmental impacts caused by urbanization has become a critical concern. Sprawling cities accelerate the phenomenon of soil sealing, whose impacts relative to climatology, water cycle and ecology are substantial. The "VegDUD" project, which provides the framework for the present paper, lays out a possible alternative for limiting these deleterious effects through focusing on the role of vegetation in promoting sustainable urban development. The study presented herein addresses the beneficial effect of greening building facades and rooftops in terms of both acoustic level and sound-decay time indicators at low frequency third-octave bands. This is carried out through numerical simulations in the time-domain of sound propagation in a canyon street of infinite length for various scenarios of surface vegetalization. Numerical predictions show a more significant effect in the upper part and outside the street, depending on the location of the vegetalized surfaces, frequency bands and number of reflections on the treated materials.

  2. Soil wettability in forested catchments in South Africa; as measured by different methods and as affected by vegetation cover and soil characteristics

    CSIR Research Space (South Africa)

    Scott

    2000-05-01

    Full Text Available stream_source_info scott 1_2000.pdf.txt stream_content_type text/plain stream_size 54451 Content-Encoding ISO-8859-1 stream_name scott 1_2000.pdf.txt Content-Type text/plain; charset=ISO-8859-1 Soil wettability... in forested catchments in South Africa; as measured by different methods and as affected by vegetation cover and soil characteristics D.F. Scott* CSIR, Division of Water, Environment and Forestry Technology, P.O. Box 320, Stellenbosch, 7599, South Africa...

  3. Reconstructing C3 and C4 vegetation cover using n-alkane carbon isotope ratios in recent lake sediments from Cameroon, Western Central Africa

    Science.gov (United States)

    Garcin, Yannick; Schefuß, Enno; Schwab, Valérie F.; Garreta, Vincent; Gleixner, Gerd; Vincens, Annie; Todou, Gilbert; Séné, Olivier; Onana, Jean-Michel; Achoundong, Gaston; Sachse, Dirk

    2014-10-01

    Trees and shrubs in tropical Africa use the C3 cycle as a carbon fixation pathway during photosynthesis, while grasses and sedges mostly use the C4 cycle. Leaf-wax lipids from sedimentary archives such as the long-chain n-alkanes (e.g., n-C27 to n-C33) inherit carbon isotope ratios that are representative of the carbon fixation pathway. Therefore, n-alkane δ13C values are often used to reconstruct past C3/C4 composition of vegetation, assuming that the relative proportions of C3 and C4 leaf waxes reflect the relative proportions of C3 and C4 plants. We have compared the δ13C values of n-alkanes from modern C3 and C4 plants with previously published values from recent lake sediments and provide a framework for estimating the fractional contribution (areal-based) of C3 vegetation cover (fC3) represented by these sedimentary archives. Samples were collected in Cameroon, across a latitudinal transect that accommodates a wide range of climate zones and vegetation types, as reflected in the progressive northward replacement of C3-dominated rain forest by C4-dominated savanna. The C3 plants analysed were characterised by substantially higher abundances of n-C29 alkanes and by substantially lower abundances of n-C33 alkanes than the C4 plants. Furthermore, the sedimentary δ13C values of n-C29 and n-C31 alkanes from recent lake sediments in Cameroon (-37.4‰ to -26.5‰) were generally within the range of δ13C values for C3 plants, even when from sites where C4 plants dominated the catchment vegetation. In such cases simple linear mixing models fail to accurately reconstruct the relative proportions of C3 and C4 vegetation cover when using the δ13C values of sedimentary n-alkanes, overestimating the proportion of C3 vegetation, likely as a consequence of the differences in plant wax production, preservation, transport, and/or deposition between C3 and C4 plants. We therefore tested a set of non-linear binary mixing models using δ13C values from both C3 and C4

  4. Spatial distribution and concentration of sulfur in relation to vegetation cover and soil properties on a reclaimed sulfur mine site (Southern Poland).

    Science.gov (United States)

    Likus-Cieślik, Justyna; Pietrzykowski, Marcin; Szostak, Marta; Szulczewski, Melanie

    2017-02-01

    This work aims to assess the spatial distribution and concentration of sulfur in the topsoil layer and to determine the relationships between sulfur concentration, soil pH, soil electrical conductivity, and plant cover at the reforested site of the former sulfur mine (Southern Poland). Soil samples were collected from 0 to 20 cm (topsoil) from a total of 86 sampling points in a regular square grid with sides of 150 m. Plant cover was assayed in circular plots with an area of 100 m(2), divided into a woody plant layer and herbaceous plant layer. Soil properties such as particle size distribution, pH in KCl and H2O, soil electrical conductivity (EC), soil organic carbon (SOC), total nitrogen (NT), and total sulfur (ST) were determined. The degree of soil contamination with sulfur was assessed based on the guidelines of the Institute of Soil Science and Plant Cultivation (IUNG), Poland. The results indicate that remediation and application of lime were not fully effective in spatial variation, because 33 points with sulfur contamination above 500 mg kg(-1) were observed. These spots occurred irregularly in the topsoil horizons. This high sulfur concentration in the soil did not result in severe acidification (below 4.5) in all cases, most likely due to neutralization from the application of high doses of flotation lime. High vegetative cover occurred at some points with high soil sulfur concentrations, with two points having S concentration above 40,000 mg kg(-1) and tree cover about 60%. Numerous points with high soil EC above 1500 μS cm(-1) as well as limited vegetation and high soil sulfur concentrations, however, indicate that the reclamation to forest is still not completely successful.

  5. 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

  6. Natural vegetation cover in the landscape and edge effects: differential responses of insect orders in a fragmented forest.

    Science.gov (United States)

    González, Ezequiel; Salvo, Adriana; Valladares, Graciela

    2017-10-01

    Human activities have led to global simplification of ecosystems, among which Neotropical dry forests are some of the most threatened. Habitat loss as well as edge effects may affect insect communities. Here, we analyzed insects sampled with pan traps in 9 landscapes (at 5 scales, in 100-500 m diameter circles) comprising cultivated fields and Chaco Serrano forests, at overall community and taxonomic order level. In total 7043 specimens and 456 species of hexapods were captured, with abundance and richness being directly related to forest cover at 500 m and higher at edges in comparison with forest interior. Community composition also varied with forest cover and edge/interior location. Different responses were detected among the 8 dominant orders. Collembola, Hemiptera, and Orthoptera richness and/or abundance were positively related to forest cover at the larger scale, while Thysanoptera abundance increased with forest cover only at the edge. Hymenoptera abundance and richness were negatively related to forest cover at 100 m. Coleoptera, Diptera, and Hymenoptera were more diverse and abundant at the forest edge. The generally negative influence of forest loss on insect communities could have functional consequences for both natural and cultivated systems, and highlights the relevance of forest conservation. Higher diversity at the edges could result from the simultaneous presence of forest and matrix species, although "resource mapping" might be involved for orders that were richer and more abundant at edges. Adjacent crops could benefit from forest proximity since natural enemies and pollinators are well represented in the orders showing positive edge effects. © 2016 Institute of Zoology, Chinese Academy of Sciences.

  7. Using official map data on topography, wetlands and vegetation cover for prediction of stream water chemistry in boreal headwater catchments

    Directory of Open Access Journals (Sweden)

    J.-O. Andersson

    2009-04-01

    Full Text Available A large part of the spatial variation of stream water chemistry can be related to inputs from headwater streams. In order to understand and analyse the dominant processes taking place in small and heterogeneous catchments, accurate data with high spatial and temporal resolution is necessary. In most cases, the quality and resolution of available map data are considered too poor to be used in environmental assessments and modelling of headwater stream chemistry. In this study 18 forested catchments (1–4 km2 were selected within a 120×50 km region in the county of Värmland in western Sweden. The aim was to test if topographic and vegetation variables derived from official datasets were correlated to stream water chemistry, primarily the concentration of dissolved organic carbon (DOC, but also Al, Fe and Si content. GIS was used to analyse the elevation characteristics, generate topographic indices, and calculate the percentage of wetlands and a number of vegetation classes. The results clearly show that topography has a major influence on stream water chemistry. There were strong correlations between mean slope and percentage wetland, percentage wetland and DOC, mean slope and DOC, and a very strong correlation between mean topographic wetness index (TWI and DOC. The conclusion was that official topographic data, despite uncertain or of low quality and resolution, could be useful in the prediction of headwater DOC-concentration in boreal forested catchments.

  8. Analysis of the Scaling Effects in the Area-Averaged Fraction of Vegetation Cover Retrieved Using an NDVI-Isoline-Based Linear Mixture Model

    Directory of Open Access Journals (Sweden)

    Hiroki Yoshioka

    2012-07-01

    Full Text Available The spectral unmixing of a linear mixture model (LMM with Normalized Difference Vegetation Index (NDVI constraints was performed to estimate the fraction of vegetation cover (FVC over the earth’s surface in an effort to facilitate long-term surface vegetation monitoring using a set of environmental satellites. Although the integrated use of multiple sensors improves the spatial and temporal quality of the data sets, area-averaged FVC values obtained using an LMM-based algorithm suffer from systematic biases caused by differences in the spatial resolutions of the sensors, known as scaling effects. The objective of this study is to investigate the scaling effects in area-averaged FVC values using analytical approaches by focusing on the monotonic behavior of the scaling effects as a function of the spatial resolution. The analysis was conducted based on a resolution transformation model introduced recently by the authors in the accompanying paper (Obata et al., 2012. The maximum value of the scaling effects present in FVC values was derived analytically and validated numerically. A series of derivations identified the error bounds (inherent uncertainties of the averaged FVC values caused by the scaling effect. The results indicate a fundamental difference between the NDVI and the retrieved FVC from NDVI, which should be noted for accuracy improvement of long-term observation datasets.

  9. The use of olive-mill waste compost to promote the plant vegetation cover in a trace-element-contaminated soil.

    Science.gov (United States)

    Pardo, Tania; Martínez-Fernández, Domingo; Clemente, Rafael; Walker, David J; Bernal, M Pilar

    2014-01-01

    The applicability of a mature compost as a soil amendment to promote the growth of native species for the phytorestoration of a mine-affected soil from a semi-arid area (SE Spain), contaminated with trace elements (As, Cd, Cu, Mn, Pb and Zn), was evaluated in a 2-year field experiment. The effects of an inorganic fertiliser were also determined for comparison. Bituminaria bituminosa was the selected native plant since it is a leguminous species adapted to the particular local pedoclimatic conditions. Compost addition increased total organic-C concentrations in soil with respect to the control and fertiliser treatments, maintained elevated available P concentrations throughout the duration of the experiment and stimulated soil microbial biomass, while trace elements extractability in the soil was rather low due to the calcareous nature of the soil and almost unaltered in the different treatments. Tissue concentrations of P and K in B. bituminosa increased after the addition of compost, associated with growth stimulation. Leaf Cu concentration was also increased by the amendments, although overall the trace elements concentrations can be considered non-toxic. In addition, the spontaneous colonisation of the plots by a total of 29 species of 15 different families at the end of the experiment produced a greater vegetation cover, especially in plots amended with compost. Therefore, the use of compost as a soil amendment appears to be useful for the promotion of a vegetation cover and the phytostabilisation of moderately contaminated soils under semi-arid conditions.

  10. Influence of shrub cover vegetal and slope length on soil bulk density; Influencia de la cubierta vegetal arbustiva y la longitud de la ladera sobre la densidad aparente del suelo

    Energy Technology Data Exchange (ETDEWEB)

    Bienes, R.; Jimenez, R.; Ruiz, M.; Garcia-Estringana, P.; Marques, M. J.

    2009-07-01

    In arid and semiarid environments of the Mediterranean climate, the shrub species play an important role in the revegetation of abandoned lands, which enables to control the soil losses, organic material and water. In this article are compared the results obtained under different revegetation in abandoned lands in the central area of Spain. In these revegetation has been used two native shrubs: A triplex halimus (Ah) and Retama sphaerocarpa (Rs), and were analyzed the influence of these revegetation in the contents of organic material of soil and apparent density in 5 years time after planting. As control, have been considered the pieces of ground with spontaneous vegetation abandoned in the same date that the shrubs revegetation. Atriplex halimus gives to the soil a covering capable to intercept a big amount of water drops absorbing a great amount part of the kinetic energy of the rain, while provides a microclimates as a result of be able to soften the wind, the temperature and the evaporation-transpiration, which makes it efficient to control the erosion and the desertification (Le Houerou, 2000). Retama sphaerocarpa was chosen because it is a native shrub very characteristic, and, due to its symbiosis with the Bradyrhizobium, enriches the soil in nitrogen, which is taken by the nitrophilous species enhancing the spontaneous vegetal covering. (Author) 9 refs.

  11. Uso do solo e cobertura vegetal na área de influência do AHE CAPIM BRANCO I / Land use and vegetal cover in the Area Influence of AHE Capim Branco I

    Directory of Open Access Journals (Sweden)

    Jorge Luis Silva Brito

    2006-06-01

    Full Text Available The present work has as objective to identify, to delimit, to map and to evaluate the differentcategories of land use and vegetal cover gifts in the area of influence of hidroeletric exploitation(AHE Capim Branco I, using techniques of remote remote sensing and geoprocessing. Thisenterprise best situated enters geographic coordinates of 18º 43' - 18º 59' of south latitude and 47º57' - 48º 13' of longitude west of the meridian of Greenwich. The total area of mapping understands455,20 km2, enclosing part of the cities of Uberlândia, Araguari and Indianópolis. The work was developed by means of the following stages: acquisition of the images CCD/CBERS, processing ofthe same ones by means of the SPRING, for the rectification, distinction, colored composition,elaboration of the letter image and visual interpretation in “screen”. The cartographic base waselaborated from topographical maps scales 1:25.000 and converted for the digital way with theCARTALINX. The presentation of the final map was made with the ARCVIEW. The categories ofLand Use and Vegetal Cover, gifts in the study area and that they had been survey are: mata/cerradão, open pasture, closed field, vegetation in regeneration, pasture, annual culture, perennialculture, hortifruticulturas, bodies d ‘ water, reforestation, urban areas and of mixing use, seedbedof workmanships and deforested area. From the mapping, it was verified that the pasture was thecategory of bigger areal expression, occupying 48.7% of the area, followed of forest, with 19,2%,annual culture with 17,9%, vegetation in regeneration with 3,4% and perennial culture with3,3%. The too much uses appear with well lesser percentages, being able itself still to detach,urban areas and of mixing use with 2,4% and vegetables with 2,0%. To conclude, we can verify,that the adopted procedures, as well as the used materials, especially images CCD/CBERS, hadrevealed satisfactory for the development of the work.

  12. Organization of vegetation cover of aquatic ecosystems at Borodinskiy opencast coal mine dumps (Kansk forest-steppe, Eastern Siberia

    Directory of Open Access Journals (Sweden)

    D. Yu. Efimov

    2016-04-01

    Full Text Available The paper present the results of study of the floristic composition and importance of species of aquatic ecosystems on different types of technogenic surfaces of the Borodino coal mine and assessment of the impact of local factors on the structure and the dynamics of vegetation. The list of plant taxa containing 91 species of higher plants and 3 cha-rophytes. The largest amount of macrophytes species are Elodea canadensis Michx., Eleocharis palustris (L. Roem. & Schult., Hydrocharis morsus-ranae L., Potamogeton alpinus Balb., P. perfoliatus L., Sparganium emersum Rehm., Spirodela polyrhiza (L. Schleid., Typha latifolia L., Warnstorfia fluitans (Hedw. Loeske, Chara contraria A. Braun ex Kutz., the basis (up to 67.6‒70.9 % of vegetation mosaic of aquatic systems and differentiate its structure post-technogenic landscape. Sorensen index (QS = 0.63‒0.71 and Spearman rank correlation coefficient (rs = 0.29‒0.62, p < 0.01 values showed the greatest similarity between the species composition of the aquatic complexes arising on mineral surfaces planned dumps. The low level of similarity (QS = 0.13‒0.45; rs = 0.25‒0.34, p < 0.05 in spe-cies composition is typical fir ponds and wetlands formed around the perimeter of the heaps along the erosion of slopes. Non-parametric analysis of variance showed a statistically significant (p < 0.001 differentiation of the species composition of the variables values of the analyzed environmental factors: the direction of reclamation, type and age of geomorphic surfaces dumps. Aquatic complexes significantly complement and enrich the mosaic of man-made landscape of the Borodino coal mine, the potential of their diversity should be taken into account when developing plans and strategies for reclamation of disturbed areas.

  13. Role of surface wind and vegetation cover in multi-decadal variations of dust emission in the Sahara and Sahel

    Science.gov (United States)

    Kim, Dongchul; Chin, Mian; Remer, Lorraine A.; Diehl, Thomas; Bian, Huisheng; Yu, Hongbin; Brown, Molly E.; Stockwell, William R.

    2017-01-01

    North Africa, the world's largest dust source, is non-uniform, consisting of a permanently arid region (Sahara), a semi-arid region (Sahel), and a relatively moist vegetated region (Savanna), each with very different rainfall patterns and surface conditions. This study aims to better understand the controlling factors that determine the variation of dust emission in North Africa over a 27-year period from 1982 to 2008, using observational data and model simulations. The results show that the model-derived Saharan dust emission is only correlated with the 10-m winds (W10m) obtained from reanalysis data, but the model-derived Sahel dust emission is correlated with both W10m and the Normalized Difference Vegetation Index (NDVI) that is obtained from satellite. While the Saharan dust accounts for 82% of the continental North Africa dust emission (1340-1570 Tg year-1) in the 27-year average, the Sahel accounts for 17% with a larger seasonal and inter-annual variation (230-380 Tg year-1), contributing about a quarter of the transatlantic dust transported to the northern part of South America. The decreasing dust emission trend over the 27-year period is highly correlated with W10m over the Sahara (R = 0.92). Over the Sahel, the dust emission is correlated with W10m (R = 0.69) but is also anti-correlated with the trend of NDVI (R = -0.65). W10m is decreasing over both the Sahara and the Sahel between 1982 and 2008, and the trends are correlated (R = 0.53), suggesting that Saharan/Sahelian surface winds are a coupled system, driving the inter-annual variation of dust emission.

  14. Using lidar and effective LAI data to evaluate IKONOS and Landsat 7 ETM+ vegetation cover estimates in a ponderosa pine forest

    Science.gov (United States)

    Chen, X.; Vierling, Lee; Rowell, E.; DeFelice, Tom

    2004-01-01

    Structural and functional analyses of ecosystems benefit when high accuracy vegetation coverages can be derived over large areas. In this study, we utilize IKONOS, Landsat 7 ETM+, and airborne scanning light detection and ranging (lidar) to quantify coniferous forest and understory grass coverages in a ponderosa pine (Pinus ponderosa) dominated ecosystem in the Black Hills of South Dakota. Linear spectral mixture analyses of IKONOS and ETM+ data were used to isolate spectral endmembers (bare soil, understory grass, and tree/shade) and calculate their subpixel fractional coverages. We then compared these endmember cover estimates to similar cover estimates derived from lidar data and field measures. The IKONOS-derived tree/shade fraction was significantly correlated with the field-measured canopy effective leaf area index (LAIe) (r2=0.55, pvegetation index (EVI) calculated from IKONOS imagery showed a negative correlation with the field measured tree canopy effective LAI and lidar tree cover response (r2=0.30, r=−0.55 and r2=0.41, r=−0.64, respectively; pvegetation fractions in this ecosystem than using normalized difference of vegetation index (NDVI). Coarsening the IKONOS data to 30 m resolution imagery revealed a stronger relationship with lidar tree measures (r2=0.77, p<0.001) than at 4 m resolution (r2=0.58, p<0.001). Unmixed tree/shade fractions derived from 30 m resolution ETM+ imagery also showed a significant correlation with the lidar data (r2=0.66, p<0.001). These results demonstrate the power of using high resolution lidar data to validate spectral unmixing results of satellite imagery, and indicate that IKONOS data and Landsat 7 ETM+ data both can serve to make the important distinction between tree/shade coverage and exposed understory grass coverage during peak summertime greenness in a ponderosa pine forest ecosystem.

  15. Methane and nitrous oxide fluxes in relation to vegetation covers and bird activity in ice-free soils of Rip Point, Nelson Island, Antarctica

    Directory of Open Access Journals (Sweden)

    Ângela Denise Hubert Neufeld

    2015-02-01

    Full Text Available This study aimed to quantify the nitrous oxide (N2O and methane (CH4 fluxes at sites with different vegetation covers and where bird activity was present or absent using the static chamber method, on Rip Point, Nelson Island, maritime Antarctic. The sites were soils covered by Sanionia uncinata, lichens, Prasiola crispa, Deschampsia antarctica and bare soil. Seabirds used the P. crispa and D. antarctica sites as nesting areas. Soil mineral N contents, air and soil temperature and water-filled pore space were measured, and the content of total organic C and particulate organic C, total N, bulk density and texture were determined to identify controlling variables of the gas emissions. The N2O and CH4 flux rates were low for all sampling events. Mean N2O flux rates ranged from 0.11±1.93 up to 21.25±22.14 µg N2O m−2 h−1 for the soils under lichen and P. crispa cover, respectively. For the CH4 fluxes, only the P. crispa site showed a low positive mean (0.47±3.61 µg CH4 m−2 h−1. The bare soil showed the greatest absorption of CH4 (−11.92±5.7 µg CH4 m−2 h−1, probably favoured by the coarse soil texture. Bare soil and S. uncinata sites had N2O accumulated emissions close to zero. Net CH4 accumulated emission was observed only at the P. crispa site, which was correlated with NH4+ (p<0.001. These results indicate that seabird activity influences N2O and CH4 soil fluxes, while vegetation has little influence, and bare soil areas in maritime Antarctica could be greenhouse gas sinks.

  16. Landsat 8 and ICESat-2: Performance and potential synergies for quantifying dryland ecosystem vegetation cover and biomass

    Science.gov (United States)

    Glenn, Nancy F.; Neuenschwander, Amy; Vierling, Lee A.; Spaete, Lucas; Li, Aihua; Shinneman, Douglas; Pilliod, David; Arkle, Robert; McIlroy, Susan

    2016-01-01

    The Landsat 8 mission provides new opportunities for quantifying the distribution of above-ground carbon at moderate spatial resolution across the globe, and in particular drylands. Furthermore, coupled with structural information from space-based and airborne laser altimetry, Landsat 8 provides powerful capabilities for large-area, long-term studies that quantify temporal and spatial changes in above-ground biomass and cover. With the planned launch of ICESat-2 in 2017 and thus the potential to couple Landsat 8 and ICESat-2 data, we have unprecedented opportunities to address key challenges in drylands, including quantifying fuel loads, habitat quality, biodiversity, carbon cycling, and desertification.

  17. Cobertura vegetal, vermicompost y actividad microbiana del suelo en la producción de tomate Soil cover crop, vermicompost and soil microbial activity in the tomato production

    Directory of Open Access Journals (Sweden)

    Manuel Villarreal-Romero

    Full Text Available Se estudió en el cultivo de tomate, el efecto combinado de fertilización química de N, P y K con aplicación de vermicompost, cobertura vegetal del suelo con Mucuna pruriens y labranza mínima; en contraste, al sistema de labranza convencional con fertilización química y acolchado plástico del suelo; para la nutrición de las plantas, medición de algunos parámetros de calidad del fruto y la actividad microbiana del suelo de 2007 a 2008. Se establecieron cinco tratamientos para la siembra del tomate, en los dos tipos de manejo del cultivo. Los resultados mostraron rendimientos similares y calidad poscosecha (firmeza y pérdida de peso de fruto y absorción de N, P, K, Ca y Mg por las plantas de tomate, entre la labranza convencional del cultivo y el de uso de cobertura vegetal del suelo, labranza mínima y fertilización con vermicompost más 250 N-55 P-100 K. Los frutos procedentes de tratamiento T2 presentaron un comportamiento adecuado en firmeza y pérdida de peso en el estudio poscosecha y este resultado fue estadísticamente igual a los frutos del T5 durante el estudio. Las plantas de M. pruriens acumularon en su biomasa nitrógeno fijado de la atmósfera y residual del suelo en cantidad importante que estuvo disponible para el cultivo de tomate. La colonización micorrízica en las plantas de tomate y la liberación de CO2 del suelo, fueron más altas con la cobertura vegetal y vermicompost que el sistema de manejo convencional del cultivo.The combined effect of N, P and K chemical fertilizers with vermicompost was studied in tomato planting, vegetation cover of the soil with Mucuna pruriens and minimal farming; in contrast to the conventional farming system with chemical fertilizers and plastic soil padding, for plant nutrition, measurement of some fruit quality parameters and soil microbial activity from 2007 to 2008. The tomato underwent five treatments in two types of crop management. Results showed similar yields and

  18. Vegetation cover and long-term conservation of radioactive waste packages: the case study of the CSM waste disposal facility (Manche District, France).

    Science.gov (United States)

    Petit-Berghem, Yves; Lemperiere, Guy

    2012-03-01

    The CSM is the first French waste disposal facility for radioactive waste. Waste material is buried several meters deep and protected by a multi-layer cover, and equipped with a drainage system. On the surface, the plant cover is a grassland vegetation type. A scientific assessment has been carried out by the Géophen laboratory, University of Caen, in order to better characterize the plant cover (ecological groups and associated soils) and to observe its medium and long term evolution. Field assessments made on 10 plots were complemented by laboratory analyses carried out over a period of 1 year. The results indicate scenarios and alternative solutions which could arise, in order to passively ensure the long-term safety of the waste disposal system. Several proposals for a blanket solution are currently being studied and discussed, under the auspices of international research institutions in order to determine the most appropriate materials for the storage conditions. One proposal is an increased thickness of these materials associated with a geotechnical barrier since it is well adapted to the forest plants which are likely to colonize the site. The current experiments that are carried out will allow to select the best option and could provide feedback for other waste disposal facility sites already being operated in France (CSFMA waste disposal facility, Aube district) or in other countries.

  19. Vegetation Cover and Long-Term Conservation of Radioactive Waste Packages: The Case Study of the CSM Waste Disposal Facility (Manche District, France)

    Science.gov (United States)

    Petit-Berghem, Yves; Lemperiere, Guy

    2012-03-01

    The CSM is the first French waste disposal facility for radioactive waste. Waste material is buried several meters deep and protected by a multi-layer cover, and equipped with a drainage system. On the surface, the plant cover is a grassland vegetation type. A scientific assessment has been carried out by the Géophen laboratory, University of Caen, in order to better characterize the plant cover (ecological groups and associated soils) and to observe its medium and long term evolution. Field assessments made on 10 plots were complemented by laboratory analyses carried out over a period of 1 year. The results indicate scenarios and alternative solutions which could arise, in order to passively ensure the long-term safety of the waste disposal system. Several proposals for a blanket solution are currently being studied and discussed, under the auspices of international research institutions in order to determine the most appropriate materials for the storage conditions. One proposal is an increased thickness of these materials associated with a geotechnical barrier since it is well adapted to the forest plants which are likely to colonize the site. The current experiments that are carried out will allow to select the best option and could provide feedback for other waste disposal facility sites already being operated in France (CSFMA waste disposal facility, Aube district) or in other countries.

  20. A thick homogeneous vegetated cover design proves cost - and schedule-effective for the reclamation of uranium mills sites near Spokane, Washington

    Energy Technology Data Exchange (ETDEWEB)

    Blacklaw, J.; Robertson, G.; Stoffel, D.; Ahmad, J.; Fordham, E. [Washington State Dept. of Health, Olympia, WA (United States)] [and others

    1997-08-01

    The Washington State Department of Health (WDOH) has licensed two medium sized uranium mills with tailings impoundments covering 28 and 40 hectares (70 and 100 acres), respectively, The uranium mill licensees have submitted closure and reclamation plans to the state, and site-specific conditions have determined the closure design features, Conventional uranium mill cover designs usually incorporate an overall cap of one to three meters, which includes a low-permeability clay barrier layer. A technical evaluation of several uranium mill facilities that used this design was published in the fall of 1994 and reported that unexpected vegetation root damage had occurred in the low-permeability clay (or bentonite amended) barrier layers. The technical report suggested that the low-permeability design feature at some sites could be compromised within a very short time and the regulatory goal of 1,000 years performance might not be achieved. In October 1994, WDOH sponsored a technical forum meeting to consider design alternatives to address these reliability concerns. Representatives from the federal government, nuclear industry, licensees, engineering firms, and state regulatory agencies attended the workshop. Risk factors considered in the evaluation of the uranium mill reclamation plans include: (1) radon gas emanation through the cover (the air pathway), and (2) migration of hazardous and/or radioactive constituents (the groundwater pathway). Additional design considerations include site structural stability, longevity of 1,000 years, and no active (ongoing) maintenance. 9 refs.

  1. The influence of vegetation cover on debris-flow density during an extreme rainfall in the northern Colorado Front Range

    Science.gov (United States)

    Rengers, Francis; Mcguire, Luke; Coe, Jeffrey A.; Kean, Jason W.; Baum, Rex L.; Staley, Dennis M.; Godt, Jonathan W.

    2016-01-01

    We explored regional influences on debris-flow initiation throughout the Colorado Front Range (Colorado, USA) by exploiting a unique data set of more than 1100 debris flows that initiated during a 5 day rainstorm in 2013. Using geospatial data, we examined the influence of rain, hillslope angle, hillslope aspect, and vegetation density on debris-flow initiation. In particular we used a greenness index to differentiate areas of high tree density from grass and bare soil. The data demonstrated an overwhelming propensity for debris-flow initiation on south-facing hillslopes. However, when the debris-flow density was analyzed with respect to total rainfall and greenness we found that most debris flows occurred in areas of high rainfall and low tree density, regardless of hillslope aspect. These results indicate that present-day tree density exerts a stronger influence on debris-flow initiation locations than aspect-driven variations in soil and bedrock properties that developed over longer time scales.

  2. Pollen core assemblages as indicator of Polynesian and European impact on the vegetation cover of Auckland Isthmus catchment, New Zealand

    Science.gov (United States)

    Abrahim, Ghada M. S.; Parker, Robin J.; Horrocks, Mark

    2013-10-01

    Tamaki Estuary is an arm of the Hauraki Gulf situated on the eastern side of central Auckland. Over the last 100 years, Tamaki catchment has evolved from a nearly rural landscape to an urbanised and industrialised area. Pollen, 14C and glass shards analyses, were carried out on three cores collected along the estuary with the aim to reconstruct the estuary's history over the last ˜8000 years and trace natural and anthropogenic effects recorded in the sediments. Glass shard analysis was used to establish key tephra time markers such as the peralkaline eruption of Mayor Island, ˜6000 years BP. During the pre-Polynesian period (since at least 8000 years BP), regional vegetation was podocarp/hardwood forest dominated by Dacrydium cupressinun, Prumnopits taxifolia, and Metrosideros. Major Polynesian settler impact (commencing ˜700 yr BP) was associated with forest clearance as indicated by a sharp decline in forest pollen types. This coincided with an increase in bracken (Pteridium esculentum) spores and grass pollen. Continuing landscape disturbance during European settlement (commencing after 1840 AD) was accompanied by the distinctive appearance of exotic pollen taxa such as Pinus.

  3. How to implement data for improved modelling - Results from an extensive field campaign on the debris covered Lirung Glacier in the Nepalese Himalayas

    Science.gov (United States)

    Petersen, Lene; Immerzeel, Walter; Shahi, Sonika; Baral, Prashant; Pellicciotti, Francesca

    2013-04-01

    Debris covered glaciers have become a focus of current research because of growing evidence of an increase in debris cover associated with a warming climate and the effect that debris has on melt rates. Mass balance models increasingly aim at including the melt rate enhancing/reduction effect due to a thin/thick debris layer, respectively. However, knowledge about debris cover and thickness, its distribution and characteristics is limited and data are scarce, especially in the HKKH region where debris-covered glaciers are numerous. In this work we present a data set that is complementary to modelling efforts carried out to improve our understanding of processes occurring at the debris cover surface and how debris effects can be implemented into melt and mass balance models of different complexity. A key requirement for distributed melt modelling is the availability of debris cover and thickness maps and knowledge about characteristics of the debris layer and their spatial variability. An extensive field campaign was conducted from May to October 2012 on the debris covered Lirung Glacier in the Nepalese Himalayas. The collected data set consists of observations from an automatic weather station (AWS) measuring wind direction, wind speed, air and surface temperature, incoming and outgoing shortwave radiation, relative humidity and snow height, 14 sensors measuring 2 m air temperature and 7 surface temperature sensors, 3 temperature systems (tinytags) measuring temperature at the debris surface and the ice below the debris layer and one thermistors chain (with 8 temperature sensors) measuring the temperature profile in the debris layer. In the study region there is a key difference between meteorological conditions during monsoon and the dry period. We analyze separately all meteorological records for these different climatic conditions and show how temperature, albedo, relative humidity and wind speed and direction are affected. Wind speed and direction show similar

  4. Evolução da cobertura vegetal e uso agrícola do solo no município de Lagoa Seca, PB Evolution of vegetation covering and land use in the municipal district of Lagoa Seca, PB

    Directory of Open Access Journals (Sweden)

    Íris do S. Barbosa

    2009-10-01

    Full Text Available O presente estudo consiste no levantamento de informações relacionadas aos aspectos biofísicos, mapeamento e quantificação da vegetação natural e das áreas agricultáveis, mediante interpretação de fotos aéreas de 1984, análise visual de imagem digital do satélite Landsat, canais Tm³, TM4 e TM5, datada de 10 de julho de 1989 e no levantamento de coordenadas através do Sistema de Posicionamento Global (GPS, 2001. Foram elaborados, para a área em estudo, arquivos digitais georreferenciados, referentes aos temas limite municipal, cobertura vegetal natural e uso agrícola do solo, em ambos os períodos, 1984 e 2001, utilizados para a classificação da vegetação secundária dominante, na circunscrição das áreas de uso agrícola, de acordo com a prática agrícola peculiar, na identificação das fisionomias vegetais e avaliação do processo evolutivo das fisionomias no período mencionado.This study comprised of the collection of data on biophysical aspects, the mapping and quantification of natural vegetation and arable areas, through interpretation of aerial pictures taken in 1984, visual analysis of digital images from Landsat satellites, Tm³, TM4 and TM5 channels, carried out on July 10, 1989 and the survey of coordinates through the Global Positioning System (GPS, 2001. Digital geo-referenced files elaborated for the studied area comprising basic data about the municipal limit, natural vegetation covering, land use, in both periods, 1984 and 2001, were used for classification of the dominant secondary vegetation, definition of the agricultural use of soil in agreement with the peculiar agricultural practices, identification of the vegetable physiognomies and evaluation of their evolutionary process in the mentioned period.

  5. Effects of Vegetation Cover and Rainfall Intensity on Sediment-Bound Nutrient Loss, Size Composition and Volume Fractal Dimension of Sediment Particles

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guan-Hua; LIU Guo-Bin; WANG Guo-Liang; WANG Yu-Xia

    2011-01-01

    Vegetation and rainfall are two important factors affecting soil erosion and thus resulting in nutrient loss in the Chinese Loess Plateau.A field experiment was conducted to investigate the effects of rainfall intensities (60,100 and 140 mm h-1) and vegetation (Caragana korshinskii) coverages (0%,30% and 80%) on soil loss,nutrient loss,and the composition and volume fractal dimension of eroded sediment particles under simulated rainfall conditions.The results showed that vegetation cover,rainfall intensity and their interaction all had significant effects on sediment transport and the sedimentbound nutrient loss.Higher rainfall intensity and lower coverage led to higher sediment and nutrient losses.Positive linear relationships were observed between soil loss and nutrient loss.The treatments showed more significant effects on the enrichment ratio (ER) of nitrogen (ERN) than organic matter (EROM) and phosphorus (ERP).Compared with the original surface soil,the eroded sediment contained more fine particles.Under the same coverage,the clay content significantly decreased with increasing rainfall intensity.The ER of sediment-bound nutrients was positively correlated with that of clay,suggesting that the clay fraction was preferentially eroded and soil nutrients were mainly adsorbed onto or contained within this fraction.There were increments in the fractal dimension of the sediment particles compared to that of the original surface soil.Moreover,the fractal dimension was positively correlated with clay,silt,and sediment-bound OM,N,and P contents,whereas it was negatively correlated with sand content.This study demonstrated that fractal dimension analysis can be used to characterize differences in particle-size distribution and nutrient loss associated with soil erosion.

  6. Integrating vegetation index time series and meteorological data to understand the effect of the land use/land cover (LULC) in the climatic seasonality of the Brazilian Cerrado

    Science.gov (United States)

    Lins, D. B.; Zullo, J.; Friedel, M. J.

    2013-12-01

    The Cerrado (savanna ecosystem) of São Paulo state (Brazil) represent a complex mosaic of different typologies of uses, actors and biophysical and social restrictions. Originally, 14% of the state of São Paulo area was covered by the diversity of Cerrado phytophysiognomies. Currently, only 1% of this original composition remains fragmented into numerous relicts of biodiversity, mainly concentrated in the central-eastern of the state. A relevant part of the fragments are found in areas of intense coverage change by human activities, whereas the greatest pressure comes from sugar cane cultivation, either by direct replacement of Cerrado vegetation or occupying pasture areas in the fragments edges. As a result, new local level dynamics has been introduced, directly or indirectly, affecting the established of processes in climate systems. In this study, the main goal is analyzing the relationship between the Cerrado landscape changing and the climate dynamics in regional and local areas. The multi-temporal MODIS 250 m Vegetation Index (VI) datasets (period of 2000 to 2012) are integrated with precipitation data of the correspondent period (http://www.agritempo.gov.br/),one of the most important variable of the spatial phytophysiognomies distribution. The integration of meteorological data enable the development of an integrated approach to understand the relationship between climatic seasonality and the changes in the spatial patterns. A procedure to congregated diverse dynamics information is the Self Organizing Map (SOM, Kohonen, 2001), a technique that relies on unsupervised competitive learning (Kohonen and Somervuo 2002) to recognize patterns. In this approach, high-dimensional data are represented on two dimensions, making possible to obtain patterns that takes into account information from different natures. Observed advances will contribute to bring machine-learning techniques as a valid tool to provide improve in land use/land cover (LULC) analyzes at

  7. Improving Estimates of Grassland Fractional Vegetation Cover Based on a Pixel Dichotomy Model: A Case Study in Inner Mongolia, China

    Directory of Open Access Journals (Sweden)

    Fei Li

    2014-05-01

    Full Text Available Linear spectral mixture analysis (SMA is commonly used to infer fractional vegetation cover (FVC, especially for pixel dichotomy models. However, several sources of uncertainty including normalized difference vegetation index (NDVI saturation and selection of endmembers inhibit the effectiveness of SMA for the estimation of FVC. In this study, Moderate-resolution Imaging Spectroradiometer (MODIS and Landsat 8/Operational Land Imager (OLI remote sensing data for the early growing season and in situ measurement of spectral reflectance are used to determine the value of endmembers including VIsoil and VIveg, with equally weighted RVI and NDVI measures used in combination to minimize the inherent biases in pure NDVI-based FVC. Their ability to improve estimates of grassland FVC is analyzed at different resolutions. These are shown to improve FVC estimates over NDVI-based SMA models using fixed values for the endmembers. Grassland FVC changes for Inner Mongolia, China from 2000 to 2013 are then monitored using the MODIS data. The results show that changes in most grassland areas are not significant, but in parts of Hulunbeier, south Tongliao, middle Xilin Gol and Erdos, grassland FVC has increased significantly.

  8. Evaluation of Radar Backscattering Models IEM, OH, and Dubois using L and C-Bands SAR Data over different vegetation canopy covers and soil depths

    Directory of Open Access Journals (Sweden)

    S. Khabazan

    2013-09-01

    Full Text Available Several algorithms have been proposed in the literature to invert radar measurements to estimate surface soil moisture. The objective of this paper is to compare the performance of the most common surface back scattering models including the theoretical integral equation model (IEM of Fung et al. (1992, and the semi-empirical models of Oh et al. (1992, 1994, 2002 and2004 and Dubois et al. (1995. This analysis uses four AIRSAR data in L and C band together with in situ measurements (soil moisture and surface roughness over bare soil and vegetation covers area and three different soil depths. The results show that Dubois model tend to over-estimate the radar response in both bands while IEM model and Oh model frequently over-estimate the radar response in L band but under-estimate them in C band. By evaluating of all models in different soil depths, the best results were obtained in 0–3 cm depths. For vegetation area poor correlation between models backscatter simulation and radar response was observed.

  9. Evaluation of Radar Backscattering Models IEM, OH, and Dubois using L and C-Bands SAR Data over different vegetation canopy covers and soil depths

    Science.gov (United States)

    Khabazan, S.; Motagh, M.; Hosseini, M.

    2013-09-01

    Several algorithms have been proposed in the literature to invert radar measurements to estimate surface soil moisture. The objective of this paper is to compare the performance of the most common surface back scattering models including the theoretical integral equation model (IEM) of Fung et al. (1992), and the semi-empirical models of Oh et al. (1992, 1994, 2002 and2004) and Dubois et al. (1995). This analysis uses four AIRSAR data in L and C band together with in situ measurements (soil moisture and surface roughness) over bare soil and vegetation covers area and three different soil depths. The results show that Dubois model tend to over-estimate the radar response in both bands while IEM model and Oh model frequently over-estimate the radar response in L band but under-estimate them in C band. By evaluating of all models in different soil depths, the best results were obtained in 0-3 cm depths. For vegetation area poor correlation between models backscatter simulation and radar response was observed.

  10. Correlation between hydrological drought, climatic factors, reservoir operation, and vegetation cover in the Xijiang Basin, South China

    Science.gov (United States)

    Lin, Qingxia; Wu, Zhiyong; Singh, Vijay P.; Sadeghi, S. H. R.; He, Hai; Lu, Guihua

    2017-06-01

    The Xijiang River is known as the Golden Watercourse because of its role in the development of the Pearl River Delta Regional Economic System in China, which was made possible by its abundant water resources. At present, the hydrological regime of the Xijiang River has now become complicated, the water shortages and successive droughts pose a threat to regional economic development. However, the complexity of hydroclimatological processes with emphasizes on drought has not been comprehended. In order to effectively predict and develop the adaptation strategies to cope with the water scarcity damage caused by hydrological droughts, it is essential to thoroughly analyze the relationship between hydrological droughts and pre/post-dependent hydroclimatological factors. To accomplish this, the extreme-point symmetric mode decomposition method (ESMD) was utilized to reveal the periodic variation in hydrological droughts that is characterized by the Standardized Drought Index (SDI). In addition, the cross-wavelet transform method was applied to investigate the correlation between large-scale climate indices and drought. The results showed that hydrological drought had the most significant response to spring ENSO (El Niño-Southern Oscillation), and the response lags in sub-basins were mostly 8-9 months except that in Yujiang River were mainly 5 or 8 months. Signal reservoir operation in the Yujiang River reduced drought severity by 52-95.8% from January to April over the 2003-2014 time period. Similarly, the cascade reservoir alleviated winter and spring droughts in the Hongshuihe River Basin. However, autumn drought was aggravated with severity increased by 41.9% in September and by 160.9% in October, so that the land surface models without considering human intervention must be used with caution in the hydrological simulation. The response lags of the VCI (Vegetation Condition Index) to hydrological drought were different in the sub-basins. The response lag for the

  11. Influence of the vegetative cover on the fate of trace metals in retention systems simulating roadside infiltration swales.

    Science.gov (United States)

    Leroy, M C; Marcotte, S; Legras, M; Moncond'huy, V; Le Derf, F; Portet-Koltalo, F

    2017-02-15

    Large-scale outdoor mesocosms were designed and co-contaminated with metals (Cd, Pb, Zn) and organic compounds to better understand the complex functioning of urban roadside swale environments. Infiltration systems were planted with macrophytes (P. arundinaceae, J. effusus and I. pseudacorus) or grassed, and natural or spiked target metals were monitored over two years. In the non-spiked mesocosms, atmospheric metal inputs were slightly higher than outputs, leading to low metal accumulation in topsoils and to very low outflow water contamination (<0.7% of the initial metal stock). In the spiked infiltration systems that simulated point pollution through water inflow, transfer of the initial stock of metals to the deeper soil layers was quite low and outflow water contamination was very low (<0.6% of the initial stock). The main metal output from these systems occurred in the first days of their installation because of the high metal solubility in water and insufficient plant cover at that time. The infiltration systems stabilized after a few weeks, probably because of stronger sorption to soil aggregates, and because of plant root development. Mephytoextraction in plant roots was more efficient in mesocosms planted with P. arundinacea and grass. Metal phytoextraction in plant aerial parts was also better for grass and P. arundinacea, when considering metal standing stocks instead of their concentration in plants. J. effusus was a good metal accumulator, but its low aboveground biomass development was less favorable to metal removal through harvesting.

  12. Development of the late glacial Baltic basin and the succession of vegetation cover as revealed at Palaeolake Haljala, northern Estonia

    Directory of Open Access Journals (Sweden)

    Saarse, Leili

    2009-12-01

    Full Text Available The 4.5 m thick Haljala sequence in North Estonia was studied to provide information on palaeoenvironmental changes between 13 800 and 11 300 cal yr BP. Late glacial environmental history of North Estonia was reconstructed using AMS-dated pollen record, sediment composition, plant macrofossils, and ostracods. The obtained data show environmental fluctuations that are linked to the climate shifts of the Last Termination in the North Atlantic region. Decrease in the arboreal pollen accumulation rate around 13 700–13 600 and 13 300–13 100 cal yr BP refers to short deterioration of climate within the Allerød Interstadial and has been correlated with the cooling of the Greenland Interstadial GI-1c and GI-1b events, respectively. Between 13 100 and 12 850 cal yr BP the pollen accumulation rate of trees, shrubs, and herb as well as organic matter increased, indicating short-term climate amelioration and establishment of pine-birch woods. This change has been correlated with the GI-1a event. Climate deterioration during the Younger Dryas (GS-1 was inferred from the reduction of tree pollen and flourishing of cold-tolerant species, such as Artemisia, Chenopodiaceae, and Cyperaceae. New data show that ice cover of the Pandivere Upland started to perish already about 13 800 cal yr BP.

  13. Meteorological and air quality impacts of increased urban albedo and vegetative cover in the Greater Toronto Area, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Taha, Haider; Hammer, Hillel; Akbari, Hashem

    2002-04-30

    The study described in this report is part of a project sponsored by the Toronto Atmospheric Fund, performed at the Lawrence Berkeley National Laboratory, to assess the potential role of surface property modifications on energy, meteorology, and air quality in the Greater Toronto Area (GTA), Canada. Numerical models were used to establish the possible meteorological and ozone air-quality impacts of increased urban albedo and vegetative fraction, i.e., ''cool-city'' strategies that can mitigate the urban heat island (UHI), significantly reduce urban energy consumption, and improve thermal comfort, particularly during periods of hot weather in summer. Mitigation is even more important during critical heat wave periods with possible increased heat-related hospitalization and mortality. The evidence suggests that on an annual basis cool-city strategies are beneficial, and the implementation of such measures is currently being investigated in the U.S. and Canada. We simulated possible scenari os for urban heat-island mitigation in the GTA and investigated consequent meteorological changes, and also performed limited air-quality analysis to assess related impacts. The study was based on a combination of mesoscale meteorological modeling, Lagrangian (trajectory), and photochemical trajectory modeling to assess the potential meteorological and ozone air-quality impacts of cool-city strategies. As available air-quality and emissions data are incompatible with models currently in use at LBNL, our air-quality analysis was based on photochemical trajectory modeling. Because of questions as to the accuracy and appropriateness of this approach, in our opinion this aspect of the study can be improved in the future, and the air-quality results discussed in this report should be viewed as relatively qualitative. The MM5 meteorological model predicts a UHI in the order of 2 to 3 degrees C in locations of maxima, and about 1 degree C as a typical value over most

  14. Late Glacial and Holocene changes in vegetation cover and climate in southern Siberia derived from a 15 kyr long pollen record from Lake Kotokel

    Directory of Open Access Journals (Sweden)

    P. E. Tarasov

    2009-07-01

    Full Text Available In this study a radiocarbon-dated pollen record from Lake Kotokel (52°47´ N, 108°07´ E, 458 m a.s.l. located in southern Siberia east of Lake Baikal was used to derive quantitative characteristics of regional vegetation and climate from about 15 kyr BP (1 kyr=1000 cal. yr until today. Quantitative reconstruction of the late glacial vegetation and climate dynamics suggests that open steppe and tundra communities predominated in the study area prior to ca. 13.5 kyr BP and again during the Younger Dryas interval, between 12.8 and 11.6 kyr BP. The pollen-based climate reconstruction suggests lower-than-present mean January (~−38°C and July (~12°C temperatures and annual precipitation (~270–300 mm values during these time intervals. Boreal woodland replaced the primarily open landscape around Kotokel three times at about 14.8–14.7 kyr BP, during the Allerød Interstadial between 13.3–12.8 kyr BP and with the onset of the Holocene interglacial between 11.5 and 10.5 kyr BP, presumably in response to a noticeable increase in precipitation, and in July and January temperatures. The maximal spread of the boreal forest (taiga communities in the region is associated with a warmer and wetter-than-present climate (Tw~17–18°C, Tc~−19°C, Pann~500–550 mm that occurred ca. 10.8–7.3 kyr BP. During this time interval woody vegetation covered more than 50% of the area within a 21×21 km window around the lake. The pollen-based best modern analogue reconstruction suggests a decrease in woody cover percentages and in all climatic variables about 7–6.5 kyr BP. Our results demonstrate a gradual decrease in precipitation and mean January temperature towards their present-day values in the region around Lake Kotokel since that time.

  15. Reprint of “Moisture content behaviour in extensive green roofs during dry periods: The influence of vegetation and substrate characteristics”

    Science.gov (United States)

    Berretta, Christian; Poë, Simon; Stovin, Virginia

    2014-08-01

    Evapotranspiration (ET) is a key parameter that influences the stormwater retention capacity, and thus the hydrological performance, of green roofs. This paper investigates how the moisture content in extensive green roofs varies during dry periods due to evapotranspiration. The study is supported by 29 months continuous field monitoring of the moisture content within four green roof test beds. The beds incorporated three different substrates, with three being vegetated with sedum and one left unvegetated. Water content reflectometers were located at three different soil depths to measure the soil moisture profile and to record temporal changes in moisture content at a five-minute resolution. The moisture content vertical profiles varied consistently, with slightly elevated moisture content levels being recorded at the deepest substrate layer in the vegetated systems. Daily moisture loss rates were influenced by both temperature and moisture content, with reduced moisture loss/evapotranspiration when the soil moisture was restricted. The presence of vegetation resulted in higher daily moisture loss. Finally, it is demonstrated that the observed moisture content data can be accurately simulated using a hydrologic model based on water balance and two conventional Potential ET models (Hargreaves and FAO56 Penman-Monteith) combined with a soil moisture extraction function. Configuration-specific correction factors have been proposed to account for differences between green roof systems and standard reference crops.

  16. Peak discharges in steep mountain catchments in relation to rainfall variability, vegetation cover and geomorphology of the Rift Valley Escarpment of Northern Ethiopia

    Science.gov (United States)

    Gebreyohannes, Tesfaalem; Frankl, Amaury; Haile, Mitiku; Abraha, Amanuel; Monsieurs, Elise; Nyssen, Jan

    2015-04-01

    The hydrological characteristics of steep mountain streams are often considered to be mainly influenced by rainfall distribution and topography. In this study, with the objective of analyzing the runoff response of mountain catchments, a total of 340 peak stage discharges were recorded in three rainy seasons (2012-2014) in 11 sloping (27-65%) mountain catchments (0.4 - 25 km²) of the marginal western Rift Valley escarpment of Northern Ethiopia. Daily rainfall data were collected using 7 rain gauges installed at different altitudes (1623 - 2851 m a.s.l) in and nearby the catchments, and used to calculate weighted average daily rain depths over the catchments. Event peak discharges were calculated from daily measurements by 11 crest stage gauges using the Manning's equation. Percentages of land use and cover classes were detected from high resolution (0.6 m) Google Earth imagery (February 1, 2014). Morphometric characteristics of the catchments were computed from ASTER digital elevation model and topographic maps. Correlation analysis between daily rainfall and peak discharge showed direct relationship (R² = 0.5-0.94, Pfloods in mountain catchments is not only influenced by the morphometric characteristics of the catchments and by rainfall, but more importantly even by vegetation cover (forest and grasses).

  17. Effects of Vegetation Cover on Sum-mer Climate in China During 1982-2001%中国夏季气候对植被覆盖的影响:1982-2001

    Institute of Scientific and Technical Information of China (English)

    HABIB Aziz Salim; 陈晓玲; 龚健雅; 张力

    2009-01-01

    In this paper, we apply lagged correlation analysis to study the effects of vegetation cover on the summer climate in different zones of China, using NOAA/AVHRR normalized difference vegetation index (NDVl) data during the time period from 1982 to 2001 and climate data of 365 meteorological stations across China (precipitation from 1982 to 2001 and tempera-ture from 1982 to 1998). The results show that there are positive correlations between spring NDVl and summer climate (temperature and precipitation) in most zones of China; these suggest that, when the vegetation cover increases, the summer precipitation will increase, and the lagged correlations show a significant difference between zones. The stronger correlations between NDVl in previous season and summer climate occur in three zones (Mid-temperate zone, Warm-temperate zone and Plateau climate zone), and this implies that vegetation changes have more sensitive feedback effects on climate in the three zones in China.

  18. Pyrolysis compound specific isotopic analysis (δ13C and δD Py-CSIA) of soil organic matter size fractions under four vegetation covers.

    Science.gov (United States)

    Jiménez-Morillo, Nicasio T.; González-Vila, Francisco J.; Almendros, Gonzalo; De la Rosa, José M.; González-Pérez, José A.

    2015-04-01

    A chemical characterization of soil organic matter (SOM) under different ground cover from a Mediterranean climate (Doñana National Park, Andalusia, Spain) is approached using bulk δ15N, δ13C, δ18O and δD isotopic analysis (C/TC-IRMS) and δ13C and δD pyrolysis compound specific isotopic analysis (Py-CSIA: Py-GC-C/TC-IRMS). Soil samples were collected in sandy soils, Arenosols (WRB 2006) from the Doñana National Park (SW Spain) under different vegetation cover: cork oak (Quercus suber, QS), eagle fern (Pteridium aquilinum, PA), pine (Pinus pinea, PP) and rockrose (Halimium halimifolium, HH). Two size fractions; coarse (C: 1-2 mm) and fine (F: <0.05 mm) were studied from each soil. A complete conventional analytical pyrolysis (Py-GC/MS) of these samples have been studied in detail (Jiménez-Morillo et al., 2015). Bulk isotopic analysis of stable light elements (δ15N, δ13C, δ18O and δD) revealed particular isotopic signatures showing differences related with the main vegetation cover and the different soil size fraction. All samples had a carbon isotopic signature between -26 and -29 ‰, which indicated that the organic matter in the two fractions of each soil sample derived from C3-type plants. The bulk δD isotopic signature in whole soil sample indicate a lower deuterium fractionation occurs in SOM under arboreal than under no-arboreal vegetation, this can be caused by the occurrence of a higher water evaporation rate under bush vegetation and/or to differences due to leaf morphology as previously described (Leaney et al., 1985). A δ15N vs. δ18O chart may provide some clues about N origin in the soil and particularly about the original source of nitrates (Kendall et al., 1996). In in all sample and size fractions our values are in the chart area corresponding to NO3 in precipitation, with lighter δ18O (c. 20 ‰) values compatible with fertilizers may be from adjacent crops. In addition we were able to assign δ13C and δD values for a number of

  19. Comportamento vegetativo e produtivo de videiras 'Cabernet sauvignon' cultivadas sob cobertura plástica Vegetative growth and yield of 'Cabernet sauvignon' grapevine under overhead plastic covering

    Directory of Open Access Journals (Sweden)

    Clenilso Sehnen Mota

    2008-03-01

    randomized block design, with two treatments (uncovered and covered plants and four replicates of 15 plants (experimental unit. The micro-environmental changes imposed by the cover did not affect grapevines phenology. The grapevines under the cover had higher values for branches growth (length and fresh mass, and leaf expansion (area and dry mass than the uncovered ones. The berries weight and diameter were superior on grapevines under covering plastic only at earlier stages of fruit growth but not at harvest. The other variables assessed were not affected by the cover. The results show that overhead plastic covering can interfere with vegetative growth without affecting yield.

  20. 毛乌素沙地植被覆盖变化的遥感分析%Remote Sensing Analysis of Vegetation Cover Change of Mu Us Sandland

    Institute of Scientific and Technical Information of China (English)

    黄永诚; 孙建国; 颜长珍

    2014-01-01

    为了防止毛乌素沙地沙漠化、改善生态环境质量,近10年国家在该区域实施了一系列生态环境建设工程。这些工程的主要目标就是恢复退化植被,提高植被覆盖率。本研究基于2000年、2005年、2010年三期的Landsat数据,利用eCognition软件中面向对象分类技术和地理信息系统的叠加分析功能,分析了2000~2010年间毛乌素沙地植被覆盖变化情况。同时,通过MODIS-NDVI数据计算分析了植被覆盖度的变化趋势。研究得出:1)该区域草地大幅度增加,尤其是2005年到2010年之间,增加更加明显;林地基本稳定;旱地由于退耕还林等政策有所减少;2)近10年来毛乌素沙地植被覆盖度呈逐步增加趋势,西北部和东南部增加尤为明显。产生上述变化的自然因素和人为因素的贡献率需要进一步研究。%To prevent the land desertification and improve the ecological environmental quality , a series of ecological environment con-struction projects have been implemented for Mu Us Sandland by the country during the nearly 10 years.One of the main effects of these projects is to restore the degradation vegetation and increase the vegetation coverage .This study analyze the vegetation cover change of Mu Us Sandland from the year 2000 to 2010 by using the object -oriented classification technique of eCongnition software and the overlay analysis function of geographic information system , based on Landsat data of the three stages which respectively are 2000, 2005 and 2010.Meanwhile, the variation trend of vegetation coverage is calculated and analyzed with the MODIS -NDVI data. The conclusions are:(1) the grassland area of Mu Us Sandland increases significantly , especially the period between 2005 and 2010;the area of forest land is basically stable;the area of dry land decrease because of some policies , such as the policy converting farm-land into forest and so on;(2)the vegetation coverage

  1. Vegetation Cover and Habitat Heterogeneity derived from QuickBird data as proxies of Local Plant Species Richness in recently burned areas

    Science.gov (United States)

    Viedma, Olga; Torres, Ivan; Moreno, Jose Manuel

    2010-05-01

    In fire-prone ecosystems, it is very common that, following fire, plant species richness increases very markedly, mainly due to an explosion of annuals, following a rapid change during the first few years after the blaze. Herbs play a major role in the system, among other, by fixing nutrients that might be lost, or by changing competitive interactions with shrubs or tree seedlings. But assessing species richness, particularly, herbaceous one, in space and at large scale is very costly. Furthermore, the scale of measurement is also important. In this work we attempted to asses plant species richness during the first year after fire in an abandoned dehesa (open parkland) at three scales (1 m2, 25 m2 and 100 m2) using QuickBird images. The study area was located in Central Spain (Anchuras, Ciudad Real), and was affected by a large summer fire (ca. 2000 ha). Before the fire the system was composed of a shrubland intermixed with trees and open spaces. Two 90x180 m plots were selected and field species richness measures were made at the three scales, using a nested design. Field-based data were related to remotely sensed data using Regression Trees (RT) and Boosted Regression Trees (BRT) modelling. Explanatory spectral and textural remotely sensed data were ecologically interpreted based on vegetation cover ground-based data. We found that areas with low spectral contrast and high reflectivity were dominated by herbaceous species, and had greater species richness than those characterized by low contrast and medium-low reflectivity, which were dominated by shrubs and trees. The highest species richness was found in the areas characterized by high contrast and medium-high reflectivity, which had a mix of herbs and woody layers. Variance explained varied depending on the modelling approach and the scale, from 21% and 50% for 1 m2 using RT and BRT, respectively; to 65% and 79% for 100 m2. The contribution of different life forms in model fitting was scale-dependent. At

  2. Macrofauna invertebrada edáfica em cultivo de mandioca sob sistemas de cobertura do solo Edaphic invertebrate macrofauna in cassava cultivation under vegetable cover crops

    Directory of Open Access Journals (Sweden)

    Rogério Ferreira da Silva

    2007-06-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito do cultivo da mandioca em diferentes sistemas de cobertura do solo na densidade e diversidade da comunidade da macrofauna de invertebrados edáfica. O trabalho foi conduzido no Município de Glória de Dourados, MS, num Argissolo Vermelho, sob sistema convencional (SC, plantio direto sobre palhada de mucuna (PDMu, sorgo (PDSo e milheto (PDMi, além de sistema com vegetação nativa (VN, como referencial para comparação. As avaliações foram realizadas em quatro épocas distintas: abril/2003 (antes do plantio, novembro/2003 (6 meses após o plantio, abril/2004 (11 meses após o plantio e novembro/2004 (18 meses após o plantio. Houve efeito da interação entre os sistemas avaliados e as épocas de amostragens sobre a densidade, riqueza e diversidade da macrofauna invertebrada do solo. Entre os grupos da macrofauna invertebrada do solo, cupins, formigas e coleópteros (imaturo e adulto foram predominantes no ambiente estudado. O uso de plantas de cobertura no pré-cultivo de mandioca no sistema plantio direto proporcionou condições para a recomposição da comunidade de macrofauna invertebrada do solo, o que indica que as espécies utilizadas, mucuna, sorgo e milheto, representam alternativas promissoras para melhor manejo dessa cultura.The objective of this work was to evaluate the effect of cassava cultivation under different vegetable cover crops according to the density and diversity of soil invertebrate macrofauna. Field experiment was carried out at Glória de Dourados, Mato Grosso do Sul State, Brazil, on an Oxisol, under conventional drilling (SC, no-tillage system under Stizolobium cinereum (PDMu, Sorghum bicolor (PDSo and Pennisetum glaucum (PDMi mulching, with comparison of native vegetation system (VN. Evaluations were performed in April/2003 (before sowing, November/2003 (6 months after sowing, April/2004 (11 months after sowing and November/2004 (18 months after sowing. Significant

  3. Diversity and stability of arthropod community in peach orchard under effects of ground cover vegetation%桃园生草对桃树节肢动物群落多样性与稳定性的影响

    Institute of Scientific and Technical Information of China (English)

    蒋杰贤; 万年峰; 季香云; 淡家贵

    2011-01-01

    A comparative study was conducted on the arthropod community in peach orchards with and without ground cover vegetation. In the orchard with ground cover vegetation, the individuals of beneficial, neutral, and phytophagous arthropods were 1. 48, 1. 84 and 0. 64 times of those in the orchard without ground cover vegetation, respectively, but the total number of arthropods had no significant difference with that in the orchard without ground cover vegetation. The species richness, Shannon' s diversity, and Pielou' s evenness index of the arthropods in the orchard with ground cov-er vegetation were 83. 733±4. 932, 4. 966±0. 110, and 0. 795±0. 014, respectively, being signifi-cantly higher than those in the orchard without ground cover vegetation, whereas the Berger-Parker' s dominance index was 0. 135±0. 012, being significantly lower than that (0. 184±0. 018) in the orchard without ground cover vegetation. There were no significant differences in the stability indices S/N and Sd/Sp between the two orchards, but the Nn/Np, Nd/Np, and Sn/Sp in the orchard with ground cover vegetation were 0. 883±0. 123. 1714±0. 683, and 0. 781 ±0. 040, respectively, being significantly higher than those in the orchard without ground cover vegetation. Pearson' s cor-relation analysis indicated that in the orchard with ground cover vegetation, the Shannon' s diversity index was significantly negatively correlated with Nd/Np, Sd/Sp, and S/N but had no significant correlations with Nn/Np and Sn/Sp, whereas in the orchard without ground cover vegetation, the di-versity index was significantly positively correlated with Nn/Np and Nd/Np and had no significant correlations with Sd/Sp ,Sn/Sp, and S/N.%对种植白三叶草的桃园(生草桃园)和非生草桃园的桃树节肢动物群落进行分析比较.结果表明:生草桃园桃树天敌、中性类群和植食类群数量分别是非生草桃园的1.48、1.84和0.64倍,而节肢动物群落个体总数无显著差异;与非

  4. Efectos de la instalación de un gasoducto sobre algunas propiedades del suelo superficial y la cobertura vegetal en el NE de Chubut Gas-pipeline installation effects on superficial soil properties and vegetation cover in Northeastern Chubut

    Directory of Open Access Journals (Sweden)

    Esteban Kowaljow

    2008-07-01

    , sobre todo, por la baja calidad de los sedimentos extraídos de los horizontes inferiores de la zanja.In this work we describe the impact of a gas-pipeline installation and the replacing of the material removed in part of the clear-cutting, on some physical and chemical properties of the soils and vegetation in three ecological sites of Northeastern Chubut. In these sites we identified four different areas: area 1, clear-cut strip, where the traffic of heavy machinery was intense; area 2, clear-cut strip, with soil and vegetation replaced; and other two areas in the undisturbed adjacent steppe: mounds associated to shrubs and mound interspaces. The highest bulk densities were recorded in area 1 and in the mound interspaces (1.43 Mg m-3. The penetrometer resistance was significantly higher in the areas 1 and 2, recording values higher than 1 MPa. The infiltration rate was much higher in the mound (261 mm h-1 than in the other areas. The infiltration rate of area 2 (85 mm h-1 was higher than that of area 1 (35 mm h-1 and the mound interspaces (50 mm h-1. Total nitrogen and organic carbon content in soils of the areas 1 and 2 were similar to those of the mound interspaces and significantly lower than those of the mound, except in the area 2 of one ecological site. Clear-cut and topsoil removal, and the subsequent traffic of heavy machinery caused by underground gas-pipeline installation produced a strong impact on the physical properties of these soils. The main limitation in the highly disturbed soils was the decrease in the infiltration rate, mainly due to high compaction and low porosity. This may in part explain the slow vegetation cover recovery in the area 1. The replacement of the stripped sediment and vegetation on the disturbed strip did not improve the recovery of the vegetation cover. It was mainly due to the low quality of the sediments extracted from the pipeline ditch.

  5. An unusual case of infective endocarditis: extension of a tricuspid valve vegetation into the left atrium through a patent foramen ovale.

    Science.gov (United States)

    Johri, Amer M; Kovacs, Katherine A; Kafka, Henryk

    2009-07-01

    Tricuspid valve endocarditis frequently occurs in the setting of intravenous drug use. A case of tricuspid valve endocarditis in a 37-year-old woman with a history of intravenous cocaine use is described. Transthoracic echocardiography showed extension of the tricuspid valve mass through a patent foramen ovale and into the left atrium. One week after intravenous antibiotic treatment, the mass no longer traversed the patent foramen ovale, and only two smaller tricuspid valve vegetations remained. The present case demonstrates the value of performing a complete and thorough transthoracic echocardiography to visualize and evaluate both the right- and left-sided consequences of infective endocarditis in intravenous drug users. It also serves as a useful reminder to physicians caring for such patients that right sided endocarditis can have important left-sided complications.

  6. Study of mineral content (Nutrients and Trace elements) in vine leaf and 4 weed species included in the vegetal cover in a Spanish vineyard.

    Science.gov (United States)

    Amorós, José Angel; Bravo, Sandra; Pérez-de-los-Reyes, Caridad; Jesús García-Navarro, Francisco; Higueras, Pablo; Campos, Juan Antonio; María Moreno, Marta

    2016-04-01

    The content of some mineral elements (Na, Ca, Mg, K, P, S, Fe, Mn, Si, Al, V, Cr, Cu, Rb, Sr, Ba, Zn, Pb, Ce, La and Nd) has been studied in vine leaf and four weed species (Mendicago lupulina L.; Malva sylvestris L., Hordeum murinum L. and Scandix pecten-veneris L.) included in the natural vegetal cover of a vineyard sited in Ciudad Real province (Central Spain). Samples were taken in May 2015, dried and milled in order to analyze them using the X Ray Fluorescence Technique. The results obtained have been compared with those measured in a vineyard located in a different site and with those suggested by the literature consulted for plants in general all around the world. The results indicate that some differences in mineral content among the weed species can be drafted. Great differences have been found in K, Si, Ca and Zn, although other elements, such as Mg, P, S, Ba and Nd, remained almost constant despite of the species. Moreover, the influence of the type of soil (different site) can give a different composition of the vine leaf in some elements. This last point is especially evident in the case of the Sr (more present in calcareous soils and leaves of plants grown on them, reaching 377 mg kg-1 versus less than 86 mg kg-1 in the non-calcareous studied soil).

  7. Discriminação da cobertura vegetal do Cerrado matogrossense por meio de imagens MODIS Discrimination of Cerrado vegetation cover in the state of Mato Grosso using MODIS images

    Directory of Open Access Journals (Sweden)

    Gustavo Bayma Siqueira da Silva

    2010-02-01

    Full Text Available O objetivo do presente trabalho foi avaliar o potencial de uso do modelo linear de mistura espectral (MLME, aplicado em imagens "Moderate Resolution Imaging Spectroradiometer" (MODIS, para discriminar as classes de cobertura vegetal natural e antropogênica do Cerrado matogrossense. O monitoramento do bioma Cerrado está se tornando muito importante devido à sua forte antropização, principalmente nas últimas quatro décadas. Nesse contexto, o sensor MODIS apresenta-se como opção devido à sua alta resolução temporal. Entretanto, considerando sua moderada resolução espacial, é indicada a decomposição de sua resposta espectral. O MLME apresenta-se como uma técnica viável, pois permite estimar o percentual dos componentes do pixel. Os dados utilizados nos perfis temporais das classes corresponderam às seguintes imagens fração do MLME: vegetação, solo e sombra. A discriminação das classes naturais e antropogênicas foi avaliada por meio do cálculo da distância Mahalanobis e apresentada por meio de dendrogramas. As imagens fração permitem análises de séries temporais na caracterização espacial e temporal das classes. As imagens fração solo e sombra, na estação seca, apresentam melhores resultados na discriminação das classes selecionadas. Para discriminação de classes com composições florísticas semelhantes, são indicadas as imagensfraçãoda estação chuvosa.The objective of the present work was to evaluate the potential of the spectral linear mixture model (SLMM, applied to Moderate Resolution Imaging Spectroradiometer (MODIS images, to discriminate natural and anthropic classes of vegetation in the portion of Mato Grosso state covered by Cerrado vegetation. The monitoring of the Cerrado biome is becoming very important due to its strong human disturbance, especially in the last four decades. In this context, the MODIS sensor appears as an option due to its high temporal resolution. However, considering

  8. Remote sensing-based vegetation indices for monitoring vegetation change in the semi-arid region of Sudan

    Science.gov (United States)

    R. A., Majdaldin; Osunmadewa, B. A.; Csaplovics, E.; Aralova, D.

    2016-10-01

    Land degradation, a phenomenon referring to (drought) in arid, semi-arid and dry sub-humid regions as a result of climatic variations and anthropogenic activities most especially in the semi-arid lands of Sudan, where vast majority of the rural population depend solely on agriculture and pasture for their daily livelihood, the ecological pattern had been greatly influenced thereby leading to loss of vegetation cover coupled with climatic variability and replacement of the natural tree composition with invasive mesquite species. The principal aim of this study is to quantitatively examine the vigour of vegetation in Sudan through different vegetation indices. The assessment was done based on indicators such as soil adjusted vegetation index (SAVI). Cloud free multi-spectral remotely sensed data from LANDSAT imagery for the dry season periods of 1984 and 2009 were used in this study. Results of this study shows conversion of vegetation to other land use type. In general, an increase in area covered by vegetation was observed from the NDVI results of 2009 which is a contrast of that of 1984. The results of the vegetation indices for NDVI in 1984 (vegetated area) showed that about 21% was covered by vegetation while 49% of the area were covered with vegetation in 2009. Similar increase in vegetated area were observed from the result of SAVI. The decrease in vegetation observed in 1984 is as a result of extensive drought period which affects vegetation productivity thereby accelerating expansion of bare surfaces and sand accumulation. Although, increase in vegetated area were observed from the result of this study, this increase has a negative impact as the natural vegetation are degraded due to human induced activities which gradually led to the replacement of the natural vegetation with invasive tree species. The results of the study shows that NDVI perform better than by SAVI.

  9. Evolution of soil and vegetation cover on the bottom of drained thermokarst lake (a case study in the European Northeast of Russia)

    Science.gov (United States)

    Kaverin, Dmitry; Pastukhov, Alexander

    2015-04-01

    The evolution of soils and landscapes has been studied in a lake bed of former thermokarst lake, which was totally drained in 1979. Melioration of thermokarst lakes was conducted experimentally and locally under Soviet economics program during 1970-s. The aim of the program was to increase in biomass productivity of virgin tundra permafrost-thermokarst sites under agricultural activities. The former thermokarst lake "Opytnoe" located in the Bolshezemelskaya Tundra, Russian European Northeast. The lake bed is covered by peat-mineral sediments, which serves as soil-forming sediments favoring subsequent permafrost aggradation and cryogenic processes as well. Initially, after drainage, swampy meadows had been developed almost all over the lake bed. Further on, succession of landscape went diversely, typical and uncommon tundra landscapes formed. When activated, cryogenic processes favored the formation of peat mounds under dwarf shrub - lichen vegetation (7% of the area). Frost cracks and peat circles affected flat mounds all over the former lake bottom. On drained peat sites, with no active cryogenic processes, specific grass meadows on Cryic Sapric Histosols were developed. Totally, permafrost-affected soils occupy 77% of the area (2011). In some part of the lake bed further development of waterlogging leads to the formation of marshy meadows and willow communities where Gleysols prevail. During last twenty years, permafrost degradation has occurred under tall shrub communities, and it will progress in future. Water erosion processes in the drained lake bottom promoted the formation of local hydrographic network. In the stream floodplain grassy willow-stands formed on Fluvisols (3% of the area). The study has been conducted under Clima-East & RFBR 14-05-31111 projects.

  10. Simulation of green roof runoff under different substrate depths and vegetation covers by coupling a simple conceptual and a physically based hydrological model.

    Science.gov (United States)

    Soulis, Konstantinos X; Valiantzas, John D; Ntoulas, Nikolaos; Kargas, George; Nektarios, Panayiotis A

    2017-09-15

    In spite of the well-known green roof benefits, their widespread adoption in the management practices of urban drainage systems requires the use of adequate analytical and modelling tools. In the current study, green roof runoff modeling was accomplished by developing, testing, and jointly using a simple conceptual model and a physically based numerical simulation model utilizing HYDRUS-1D software. The use of such an approach combines the advantages of the conceptual model, namely simplicity, low computational requirements, and ability to be easily integrated in decision support tools with the capacity of the physically based simulation model to be easily transferred in conditions and locations other than those used for calibrating and validating it. The proposed approach was evaluated with an experimental dataset that included various green roof covers (either succulent plants - Sedum sediforme, or xerophytic plants - Origanum onites, or bare substrate without any vegetation) and two substrate depths (either 8 cm or 16 cm). Both the physically based and the conceptual models matched very closely the observed hydrographs. In general, the conceptual model performed better than the physically based simulation model but the overall performance of both models was sufficient in most cases as it is revealed by the Nash-Sutcliffe Efficiency index which was generally greater than 0.70. Finally, it was showcased how a physically based and a simple conceptual model can be jointly used to allow the use of the simple conceptual model for a wider set of conditions than the available experimental data and in order to support green roof design. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Assessment Impacts of Weather and Land Use/Land Cover (LULC Change on Urban Vegetation Net Primary Productivity (NPP: A Case Study in Guangzhou, China

    Directory of Open Access Journals (Sweden)

    Xiantie Zeng

    2013-08-01

    Full Text Available Net primary productivity (NPP can indicate vegetation ecosystem services ability and reflect variation response to climate change and human activities. This study applied MODIS-1 km NPP products to investigate the NPP variation from 2001 to 2006, a fast urban expansion and adjustment period in Guangzhou, China, and quantify the impacts of weather and land use/land cover (LULC changes, respectively. The results showed that the NPP mean value increased at a rate of 11.6 g∙C∙m−2∙yr−1 during the initial three years and decreased at an accelerated rate of 31.0 g∙C∙m−2∙yr−1 during the final three years, resulting in a total NPP loss of approximately 167 × 106 g∙C. The spatiotemporal of NPP varied obviously in the central area, suburb and exurb of Guangzhou driven by three patterns of weather and LULC changes. By the interactive effects and the weather variation dominated effects, NPP of most areas changed slightly with dynamic index less than 5% of NPP mean value in the central area and the suburb. The LULC change dominated effects caused obvious NPP reduction, by more than 15% of the NPP mean value, which occurred in some areas of the suburb and extended to the exurb with the outward urban sprawl. Importantly, conversion from wood grassland, shrublands and even forests to croplands occupied by urban landscapes proved to be a main process in the conversion from high-NPP coverage to low-NPP coverage, thereby leading to the rapid degradation of urban carbon stock capacity in urban fringe areas. It is helpful for government to monitor urban ecological health and safety and make relevant policies.

  12. O factor de coberto vegetal, para árvores e Arbustos, em modelos de erosão hídrica The vegetation cover factor, for tree and bush canopies, in models of water erosion

    Directory of Open Access Journals (Sweden)

    Carla Rolo Antunes

    2011-07-01

    Full Text Available O objectivo primordial do presente trabalho consiste na análise do comportamento de cobertos arbóreos e arbustivos, em termos do processo de intercepção da precipitação, designadamente, retenção e gotejo, e no estabelecimento de uma componente a incluir em modelos de erosão, que permita quantificar o factor de coberto vegetal em caso de ocupação do solo por estes cobertos, associados a culturas arvenses, em subcoberto, particularmente, na Equação Universal da Perda de Solo Revista (RUSLE. O trabalho experimental utilizou um simulador de chuva, tendo-se obtido valores do diâmetro das gotas (gotejo das folhas de espécies características dos sistemas de uso do solo mais comuns no Sul de Portugal, nomeadamente sobreiro (Quercus suber L., azinheira (Quercus ilex L. ssp. rotundifolia Lam e carrasco (Quercus coccifera L., e quantificado valores de retenção nas folhas. A partir dos resultados obtidos estimou-se a energia cinética para diferentes alturas de queda e, consequentemente, valores correctivos a aplicar aos valores de C tradicionalmente considerados, relativos às culturas agrícolas.The main objective of this work consists on the analyzes of tree and bush canopies behavior, in terms of the rainfall interception process, namely, leave retention, and dripping, and the establishment of a erosion model component to include in to quantify the cover factor (C of the Revised Universal Soil Loss Equation (RUSLE for mixed land covered systems with arable crops, in association with trees and bushes. In the experimental work a rainfall simulator was used and the characteristic values for the diameter of the dripping drops and retention of the leaves from characteristic species of the more common mixed land-use systems in Southern of Portugal, particularly with Cork oak (Quercus suber L., Holm or evergreen oak (Quercus ilex L. ssp. rotundifolia Lam and Kermes or wild oak (Quercus coccifera L., were obtained. From the obtained results

  13. GAP Land Cover - Image

    Data.gov (United States)

    Minnesota Department of Natural Resources — This raster dataset is a simple image of the original detailed (1-acre minimum), hierarchically organized vegetation cover map produced by computer classification of...

  14. GAP Land Cover - Vector

    Data.gov (United States)

    Minnesota Department of Natural Resources — This vector dataset is a detailed (1-acre minimum), hierarchically organized vegetation cover map produced by computer classification of combined two-season pairs of...

  15. 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.

  16. Impact of natural climate change and historical land use on vegetation cover and geomorphological process dynamics in the Serra dos Órgãos mountain range in Rio de Janeiro State, Brazil

    Science.gov (United States)

    Nehren, U.; Sattler, D.; Heinrich, J.

    2010-03-01

    The Serra dos Órgãos mountain range in the hinterland of Rio de Janeiro contains extensive remnants of the Atlantic Forest (Mata Atlântica) biome, which once covered about 1.5 million km² from Northeast to South Brazil and further inland to Paraguay and Argentina. As a result of historical deforestation and recent land use intensification processes today only 5 to 8% of the original Atlantic Forest remains. Despite the dramatic habitat loss and a high degree of forest fragmentation, the remnants are among the Earth’s most diverse habitats in terms of species richness. Furthermore, they are characterized by a high level of endemism. Therefore, the biome is considered a "hotspot of biodiversity". In the last years many efforts have been taken to investigate the Mata Atlântica biome in different spatial and time scales and from different scientific perspectives. We are working in the Atlantic Forest of Rio de Janeiro since 2004 and focus in our research particularly on Quaternary landscape evolution and landscape history. By means of landscape and soil archives we reconstruct changes in the landscape system, which are mainly the result of Quaternary climate variability, young tectonic uplift and human impact. The findings throw light on paleoecological conditions in the Late Quaternary and the impact of pre-colonial and colonial land use practices on these landscapes. In this context, a main focus is set on climate and human-driven changes of the vegetation cover and its consequences for the geomorphological process dynamics, in particular erosion and sedimentation processes. Research methods include geomorphological field studies, interpretation of satellite images, physical and chemical sediment and soil analyses as well as relative and absolute dating (Feo/Fed ratio and 14C dating). For the Late Quaternary landscape evolution, the findings are compared with results from paleoclimatic and paloecological investigations in Southeast and South Brazil using other

  17. Modeling percentage vegetation cover of a desert area using Landsat 8-OLI image%基于Landsat 8-OLI的荒漠化地区植被覆盖度反演模型研究

    Institute of Scientific and Technical Information of China (English)

    马中刚; 孙华; 王广兴; 林辉; 佘宇晨; 邹琪

    2016-01-01

    Percentage vegetation cover is a direct and effective measure used to assess and monitor desertification. In this study, a novel method that combined stepwise regression and linear spectral unmixing analysis was developed to derive an integrated regression model of percentage vegetation cover against image vegetation indices and vegetation fraction. A total of 134 sample plots were systematically selected in the study area–Kangbao County and percentage vegetation cover data that quantified desertification were collected. Landsat 8-OLI image was acquired and a total of 16 vegetation indices were calculated. Linear spectral unmixing analysis was conducted to extract vegetation fraction of mixed pixels that were introduced into stepwise regression. The results were validated using the observations of sample plots and showed that: (1) When individual vegetation indices were used to develop regression models, the vegetation indices that had the highest correlation were normalized difference vegetation index (NDVI) and soil adjusted vegetation index (SAVI). In the case of stepwise regression modeling, soil adjusted vegetation index (SAVI0.5), simple ratio (SRN-R) and enhanced vegetation index (EVI) had significant contributions and were selected. (2) When only vegetation fraction from linear spectral unmixing analysis was used as an independent variable, the coefficient of determination for the obtained model was 0.673, lower than the coefficient from stepwise regression, but higher than those when individual vegetation indices were employed. (3) The results of accuracy assessment showed that the stepwise regression based on the vegetation indices led to the coefficient of determination R2 and accuracy of 0.719 and 86.70%, and the new method that introduced vegetation fraction together with the vegetation indices as independent variables into the stepwise regression resulted in the coefficient of determination R2 and accuracy of 0.807 and 92.37%. This implied that the

  18. Analysis of the Effects of Drought on Vegetation Cover in a Mediterranean Region through the Use of SPOT-VGT and TERRA-MODIS Long Time Series

    Directory of Open Access Journals (Sweden)

    Mehrez Zribi

    2016-12-01

    Full Text Available The analysis of vegetation dynamics and agricultural production is essential in semi-arid regions, in particular as a consequence of the frequent occurrence of periods of drought. In this paper, a multi-temporal series of the Normalized Difference of Vegetation Index (NDVI, derived from SPOT-VEGETATION (between September 1998 and August 2013 and TERRA-MODIS satellite data (between September 2000 and August 2013, was used to analyze the vegetation dynamics over the central region of Tunisia in North Africa, which is characterized by a semi-arid climate. Products derived from these two satellite sensors are generally found to be coherent. Our analysis of land use and NDVI anomalies, based on the Vegetation Anomaly Index (VAI, reveals a strong level of agreement between estimations made with the two satellites, but also some discrepancies related to the spatial resolution of these two products. The vegetation’s behavior is also analyzed during years affected by drought through the use of the Windowed Fourier Transform (WFT. Discussions of the dynamics of annual agricultural areas show that there is a combined effect between climate and farmers’ behavior, leading to an increase in the prevalence of bare soils during dry years.

  19. 西南地区近14a植被覆盖变化及其与气候因子的关系%VEGETATION COVER CHANGE OVER THE SOUTHWEST CHINA AND ITS RELATION TO CLIMATIC FACTORS

    Institute of Scientific and Technical Information of China (English)

    张勃; 王东; 王桂钢; 马琼; 张国斌; 季定民

    2015-01-01

    The vegetation is important to maintain the ecological environment in the earth,and it is affected by climate factors significantly.Dynamic monitoring of the vegetation variation could reflect the trend of climate change to some extent.Vegetation cover change is one of the cores of global environmental change research,but also the front and hot field of modern physical geography.SPOT AVHRR NDVI (Normalized Difference Vegetation Index) in the Southwest during the period from 1999 to 2012 was selected to get the vegetation cover change information based on GIS and RS technology.The temporal and spatial vegetation cover change were analyzed by using spatial data covering the Southwest in the past 14 years,and discussed the relationship between major climatic factors (temperature,precipitation and SPED and the vegetation.The results are shown as follows.(1) From 1999 to 2012,NDVI vegetation of the Southwest had an entirely rising trend,with the growth of 6.9%/10 a,and this was faster than average of China.There were some significant spatial differences of the vegetation cover change,and the NDVI of the seven vegetation types increased significantly.Meanwhile the vegetation coverage appeared improvement as a whole area.The NDVI decreased area covered only about 1.18 % of the whole study area.The decreased area was mainly distributed on the north of Hengduan Mountains,the east of Sichuan Basin and the central part of Yungui Plateau.(2) The Hurst index of NDVI time series shows that the vegetation restoration was sustainable,and it is expected that the area of vegetation cover change to healthy development,but the NDVI decreased areas with strong persistence and the NDVI increased areas with weak persistence might be indicative.Grassland degradation & strong sustainability area is the largest,as well as the improvement of the mixed needle & strong sustainability area.The decreased areas with strong persistence was mainly distributed on the north central of Hengduan

  20. Accuracy analysis of vegetation cover measurement using digital photography for regular planted woodland%规则林地覆盖度照相测量法的精度分析

    Institute of Scientific and Technical Information of China (English)

    赵继强; 谢东辉; 孟夏; 穆西晗; 阎广建

    2013-01-01

    为定量研究照相法测量规则林地覆盖度中采样策略、相机非垂直拍摄等因素对覆盖度计算结果的影响,该文对河北怀来的一片梨树林进行了实地测量,通过对测量数据的统计计算,利用植被结构生成软件 Onyx tree professional重建梨树林场景,采用基于物理的光线追踪算法模拟相机拍摄的照片,提出了规则林地覆盖度照相法测量的采样方案,并通过计算机模拟检验了采样方案。通过精确控制模拟相机的拍摄条件,进一步分析了非垂直拍摄对测量精度的影响。结果表明,相机的非竖直拍摄对覆盖度计算结果的精度有较大的影响,误差最大可达27.9%。该文提出的测量方案为规则林地的覆盖度实地测量提供了参考。%Digital photography is now the most widely used method to obtain the vegetation cover in field measurements. It uses a digital camera to shoot the research area straight downward, classify the digital images into plants and soil, and calculate the percentages of the pixel numbers of plants. When measuring the vegetation cover of regular planted woodland with digital photography, the accuracy of the calculated vegetation cover is affected by following factors such as the sampling strategy and non-vertical shooting of digital camera. However, it is difficult to analyze these factors mentioned above quantitatively in situ measurement because there are lots of uncertain errors involved. In this study, we used the computer simulation method to evaluate these factors because in a computer simulated scene, we can strictly control all these uncertainties. We measured a regular planted pyrus orchard to get the structural data in Huailai (40.373°N, 115.723°E), Heibei province. Through statistics of the measured structural data, a regular planted pyrus orchard scene was reconstructed with the plants structural generating software, onyx tree professional which is widely used in forest

  1. Progress in the study of vegetation cover classification of multispectral remote sensing imagery%多光谱遥感影像植被覆盖分类研究进展

    Institute of Scientific and Technical Information of China (English)

    闫利; 江维薇

    2016-01-01

    利用多光谱遥感影像进行植被覆盖分类是目前遥感技术应用的热点研究领域之一。在广泛调研文献的基础上,综述了近年来多光谱遥感影像植被分类研究现状和进展,较全面深入地分析了各种植被分类特征、分类算法的优缺点、适应性和应用情况,指出了当前面临的难点和挑战,并对未来发展趋势进行了展望。未来多光谱遥感影像的植被分类不仅要从分类算法上进行创新,提高分类器的自动化程度、分类效率和学习速度,扩大适用范围,增强鲁棒性,而且同样不能忽视对植被分类新特征的挖掘,提高特征的可分性,融合多源数据、利用多时相影像、挖掘更多新特征参与植被分类是未来的发展趋势。%Vegetation cover classification using multispectral remote sensing imagery is a hot research area, in which various new methods emerge endlessly. On the basis of reading a large number of references, the authors summarized in this paper the status and progress of vegetation cover classification with multispectral remote sensing imagery , analyzed advantages and disadvantages, adaptation and application of each vegetation classification feature and method, pointed out current difficulties and challenge, and predicted future development trend. The analysis suggests that future vegetation cover classification of multispectral remote sensing imagery needs not only innovation of classifier in the aspects of improvement of automation, efficiency, learning rate, adaptation and robustness, but also feature mining of vegetation classification. For the purpose of enhancing such aspects as using feature reparability and fusing multisource data, the adoption of multi -temporal images and the tapping of more new features in vegetation classification seem to be future trends.

  2. 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

  3. Response of Vegetation Cover Changes to Climate Change in Daba Maintains%大巴山地区植被覆盖变化及其对气候变化的响应

    Institute of Scientific and Technical Information of China (English)

    任园园; 张哲; 侯钦磊; 贺映娜; 袁博

    2012-01-01

    利用1998—2009年的SPOT VGT-NDVI逐旬数据集,对大巴山地区植被覆盖变化及其对气候的响应进行了研究。结果表明:(1)1998—2009年大巴山地区植被NDVI值变化整体呈显著上升趋势,年平均NDVI值在0.54~0.64之间;大巴山弧形褶皱带植被NDVI值较高,河流附近NDVI值较低;大巴山地区植被覆盖呈显著性增加趋势,在县城城区附近有植被退化迹象,占总面积的0.24%。(2)1998—2009年,提取6种植被类型的NDVI值在四季的变化总体呈上升趋势,尤其是春季NDVI变化显著;不同类型的植被NDVI值大小顺序为:阔叶林〉针叶林(冬季为针叶林〉阔叶林)〉灌丛〉草甸〉草丛〉栽培植被,其中,草甸在四季的变幅最大。(3)在时间尺度上,NDVI与同期、前一个月、前两个月的气温呈极显著相关性,与降水量的相关性不显著。空间尺度上,6月月均NDVI与气温呈负相关的像元数占67%,表明该时段温度升高可能导致蒸发量增大,从而抑制了植物生长。%This paper studied vegetation cover variations and the response of vegetation changes to climate change in Daba Mountains from 1998 to 2009 based on SPOT-NDVI data.The result as follow:(1) The vege-tation cover has a significant increasable trends as a whole in Daba Mountains during 1998 to 2009,the value of annual NDVI is between 0.54 and 0.65,the NDVI value is higher in mountains,and lower near the river in space;The major area of vegetation cover had undergone changed in last decade,and the result has through the significant test.The sign of vegetation degradation distributed near the city,for the total area of 0.24%.(2) During the past 12 years,six types of vegetation cover tended to growth in significantly in seasons,especially in the spring.Beginning with the largest,the NDVI values of different vegetation types is broad-leaved forest,coniferous forest(the values is coniferous forestbroad-leaved forest in

  4. Spatio-temporal forest cover characterisation of mascareignite zones of reunion Island; Caracterisation spatio-temporelle du couvert vegetal des zones a mascareignite des hauts de l'Ile de la Reunion

    Energy Technology Data Exchange (ETDEWEB)

    Ouar, S

    1998-07-01

    The endo-soils of the reunion island often present a particularity: the presence of a light soil level on surface, of vegetable composition, the mascareignite. In the framework of this study, mascareignite soils have been localized on the wet face of the island and have been compared with those of the dry face. The floristic past of these soils has been reconstituted with the pedo-anthracology tool (charcoal dating and identification). Ages given by the {sup 14}C measures show that the mascareignite genesis is anterior to the human being presence in the island. The study of the actual vegetable cover distribution has been realized by satellite data. (A.L.B.)

  5. Influence of the height of the vegetation cover in the variation of the kinetic energy of raindrops intercepted; Influencia de la altura de la cubierta vegetal en la variacion de la energia cinetica de las gotas de lluvia interceptadas

    Energy Technology Data Exchange (ETDEWEB)

    Roldan Soriano, M.

    2009-07-01

    The erosive capacity of raindrops is function of mass (size) and terminal velocity. Drop mass and velocity govern the inherent erosivity of rainfall through kinetic energy. Kinetic energy is a very important property of the rainfall because it is one of the sources of energy in the process of water erosion. Vegetative canopy intercepts the raindrops and causes a variation on this rainfall kinetic energy due to modification of diameters and velocities distributions. If the height of canopy is enough, the bigger intercepted drops could achieve high velocities and their kinetic energies can increases. In this paper a quantitative evaluation of the increase of kinetic energy of intercepted drops is obtained and it is showed that this kinetic energy increases exponentially with vegetation height. (Author) 9 refs.

  6. Atividade da urease em latossolos sob influência da cobertura vegetal e da época de amostragem Urease activity in oxisols as influenced by vegetation cover and sampling time

    Directory of Open Access Journals (Sweden)

    Regina Márcia Longo

    2005-07-01

    Full Text Available O presente trabalho teve por objetivo avaliar o efeito do tipo de vegetação e da época de amostragem na atividade da urease em dois diferentes solos tropicais. O experimento foi instalado em Latossolo Vermelho Aluminoférrico típico e Latossolo Vermelho distrófico típico sob cinco diferentes culturas: pinus, eucalipto, citrus, soja e milho. As amostragens de solo foram efetuadas mensalmente, de abril de 1990 a março de 1991, determinando-se a atividade da urease, o N-total e o C-orgânico. A atividade da urease variou de acordo com a época de amostragem, apresentando valores mais elevados nos meses mais quentes e úmidos. A cobertura vegetal influenciou a conversão de N-uréia a N-NH4, observando-se maior atividade da urease nas amostras de solo sob pinus e eucalipto, embora, no início do ciclo das culturas da soja e do milho, a atividade da urease também tenha sido elevada.The present study aimed to evaluate the effect of the vegetation type and the sampling time on urease activity in two different tropical soils (Rhodic Oxisols. The experiment was installed in a typic alumino-ferric Red Latossol and a typic distrophic Red Latosol under five different vegetations: pinus, eucalypt, citrus, soybean and corn. The soil samples were collected from April 1990 to March 1991 and the urease activity, total nitrogen and organic carbon were determined. The urease activity changed according to the sampling time, presenting higher values in the warmer and humid months. The vegetation type affected the conversion of N-urea to N-NH4+, with higher urease activity being observed in the soil under pinus and eucalypt, although the activity was high at the beginning of the soybean and corn cropping cycle.

  7. Introducing land-cover and land-use changes in a climate scenario of the 21. century; Prise en compte des changements de vegetation dans un scenario climatique du 21. siecle

    Energy Technology Data Exchange (ETDEWEB)

    Voldoire, A

    2005-03-15

    The main objective of this work has been to run a climate simulation of the 21. century that includes not only greenhouse gases and aerosols emitted by human activity but also land-use and land-cover changes. To achieve this goal, the integrated impact model IMAGE2.2 (developed at RIVM, The Netherlands) was used, which simulates the evolution of greenhouse gases concentrations as well as land-cover changes. This model has been coupled to the general circulation model ARPEGE/OPA provided by the CNRM. Before coupling the models, sensitivity experiments with each model have been performed to test their respective sensitivity to the forcing of the other. Ultimately, a simulation with the two models coupled together has shown that interactions between climate and vegetation are not of primary importance for century scale studies. (author)

  8. Vegetation cover and relationships of habitat-type with elevation on the Mississippi-Alabama Barrier Islands in the initial six years after Hurricane Katrina

    Science.gov (United States)

    Funderburk, W.; Carter, G. A.; Anderson, C. P.; Jeter, G. W., Jr.; Otvos, E. G.; Lucas, K. L.; Hopper, N. L.

    2015-12-01

    Quantifying change in vegetation and geomorphic features which occur during and after storm impact is necessary toward understanding barrier island habitat resiliency under continued climate warming and sea level rise. In August, 2005, the Mississippi-Alabama barrier islands, including, from west-to-east, Cat, West Ship, East Ship, Horn, Petit Bois and Dauphin islands, were completely inundated by the tidal surge of Hurricane Katrina. Overwash, scouring, burial under sand, and mechanical damage combined with saltwater flooding and post-storm drought resulted in immediate and long-term vegetation loss. Remotely-sensed data acquired before (2004-2005) and after (2005-2011) Katrina were compared via image classification to determine immediate storm impacts and assess natural re-growth of land area and vegetation. By 2008, merely three years after the storm, total land area of Cat, West Ship, East Ship, Horn, Petit Bois and West Dauphin had recovered to 92, 90, 33, 99, 93 and 91 percent, and total vegetated land area to 85, 101, 85, 94, 83 and 102 percent of pre-Katrina values, respectively. Habitat-type maps developed from field survey, SPOT-5 and radar data were compared with LIDAR-derived elevation models to assess 2010 habitat-type distribution with respect to ground elevation. Although median MSL elevations associated with habitat classes ranged only from 0.5 m to 1.4 m, habitat-type changed distinctively with decimeter-scale changes in elevation. Low marsh, high marsh, estuarine shrubland, slash pine woodland, beach dune, bare sand and beach dune herbland were associated with median elevations of 0.5, 0.9, 1.0, 1.1, 1.2, 1.3 and 1.4 m ± 0.1 m, respectively. The anticipated increases in sea level and tropical storm energy under a continually warming climate will likely inhibit the reformation of higher-elevation habitat-types, such as shrublands and woodlands, in the 21st century.

  9. ANALYSIS OF IMAGERY-PRODUCING TECHNIQUES FOR DETECTION OF ANTI-PERSONNEL LANDMINES COVERED BY SHALLOW VEGETATION AND/OR SOIL - A HUMANITARIAN APPROACH

    Directory of Open Access Journals (Sweden)

    KHANDAKAR FARIDAR RAHMAN,

    2011-02-01

    Full Text Available The present paper provides a critical review about the various techniques in the detection of antipersonnel landmines used the recent past (from 1999 onwards. We have taken into consideration onlythose techniques which produce some kind of image and have been beneficial in detection of landmines hidden in shallow vegetation or soil. Our aim is to identify and analyse the effectiveness of suchtechniques in humanitarian de-mining operations in the developing countries where mine clearing prove to be very difficult due to lack of proper facilities and presence of huge population. Most of the images used and experimental results reproduced in this paper have been taken from existing works.

  10. Manejos de cobertura vegetal e velocidades de operação em condições de semeadura e produtividade de milho Management of cover vegetation and speed of operation on conditions of sowing and corn yield

    Directory of Open Access Journals (Sweden)

    Emerson Trogello

    2013-07-01

    Full Text Available Objetivou-se, com este trabalho, avaliar parâmetros da qualidade de semeadura e o desenvolvimento e rendimento da cultura do milho semeada no sistema plantio direto sobre diferentes manejos de cobertura vegetal e velocidades de operação da semeadora-adubadora na região sudoeste do estado do Paraná. Utilizou-se esquema de parcelas subdivididas, as quais constituíram os manejos de cobertura vegetal da aveia preta (aveia gradeada, rolada, triturada e dessecada e as subparcelas as velocidades de operação (4,5 e 7,0 km h-1 no delineamento de blocos ao acaso, com quatro repetições. Avaliaram-se o espaçamento entre plantas, a uniformidade de distribuição de sementes, a profundidade de semeadura, o índice de velocidade de emergência, o estande de plantas, a área de solo mobilizada e a produtividade média da cultura. Os dados tabulados foram analisados pelo teste F a 0,05 e, apresentando significância, as médias foram comparadas pelo teste de Tukey a 0,05 de probabilidade. Concluiu-se que a melhor distribuição de sementes foi observada na menor velocidade e a produtividade média da cultura não foi influenciada pelos tratamentos. Os manejos de cobertura vegetal não se mostraram eficientes na melhoria das condições de semeadura.The objective of this study was to evaluate quality parameters of sowing and the development and yield of maize sown in no tillage system under different vegetation managements and operating speeds of the seeder in the southwest region of the S tate of Paraná. A split-plot design was used, where the plots were the vegetation management of the oat (oat latticed, rolled, chopped and desiccated and split plot the operation speeds (4.5 and 7.0 km h-1, in a randomized block design with four replications. The spacing between plants, uniformity distribution of seed, sowing depth, rate of emergence, plant stand, soil area mobilized and yield of the crop were evaluated. The tabulated data were analysed by F test at

  11. A novel assessment of the role of land-use and land-cover change in the global carbon cycle, using a new Dynamic Global Vegetation Model version of the CABLE land surface model

    Science.gov (United States)

    Haverd, Vanessa; Smith, Benjamin; Nieradzik, Lars; Briggs, Peter; Canadell, Josep

    2017-04-01

    In recent decades, terrestrial ecosystems have sequestered around 1.2 PgC y-1, an amount equivalent to 20% of fossil-fuel emissions. This land carbon flux is the net result of the impact of changing climate and CO2 on ecosystem productivity (CO2-climate driven land sink ) and deforestation, harvest and secondary forest regrowth (the land-use change (LUC) flux). The future trajectory of the land carbon flux is highly dependent upon the contributions of these processes to the net flux. However their contributions are highly uncertain, in part because the CO2-climate driven land sink and LUC components are often estimated independently, when in fact they are coupled. We provide a novel assessment of global land carbon fluxes (1800-2015) that integrates land-use effects with the effects of changing climate and CO2 on ecosystem productivity. For this, we use a new land-use enabled Dynamic Global Vegetation Model (DGVM) version of the CABLE land surface model, suitable for use in attributing changes in terrestrial carbon balance, and in predicting changes in vegetation cover and associated effects on land-atmosphere exchange. In this model, land-use-change is driven by prescribed gross land-use transitions and harvest areas, which are converted to changes in land-use area and transfer of carbon between pools (soil, litter, biomass, harvested wood products and cleared wood pools). A novel aspect is the treatment of secondary woody vegetation via the coupling between the land-use module and the POP (Populations Order Physiology) module for woody demography and disturbance-mediated landscape heterogeneity. Land-use transitions to and from secondary forest tiles modify the patch age distribution within secondary-vegetated tiles, in turn affecting biomass accumulation and turnover rates and hence the magnitude of the secondary forest sink. The resulting secondary forest patch age distribution also influences the magnitude of the secondary forest harvest and clearance fluxes

  12. Testing the enemies hypothesis in peach orchards in two different geographic areas in eastern China: the role of ground cover vegetation.

    Directory of Open Access Journals (Sweden)

    Nian-Feng Wan

    Full Text Available Many studies have supported the enemies hypothesis, which suggests that natural enemies are more efficient at controlling arthropod pests in polyculture than in monoculture agro-ecosystems. However, we do not yet have evidence as to whether this hypothesis holds true in peach orchards over several geographic locations. In the two different geographic areas in eastern China (Xinchang a town in the Shanghai municipality, and Hudai, a town in Jiangsu Province during a continuous three-year (2010-2012 investigation, we sampled arthropod pests and predators in Trifolium repens L. and in tree canopies of peach orchards with and without the ground cover plant T. repens. No significant differences were found in the abundances of the main groups of arthropod pests and predators in T. repens between Hudai and Xinchang. The abundance, richness, Simpson's index, Shannon-Wiener index, and Pielou evenness index of canopy predators in ground cover areas increased by 85.5, 27.5, 3.5, 16.7, and 7.9% in Xinchang, and by 87.0, 27.6, 3.5, 17.0 and 8.0% in Hudai compared to those in the controls, respectively. The average abundance of Lepidoptera, Coleoptera, Homoptera, true bugs and Acarina canopy pests in ground cover areas decreased by 9.2, 10.2, 17.2, 19.5 and 14.1% in Xinchang, and decreased by 9.5, 8.2, 16.8, 20.1 and 16.6% in Hudai compared to that in control areas, respectively. Our study also found a higher density of arthropod species resources in T. repens, as some omnivorous pests and predators residing in T. repens could move between the ground cover and the orchard canopy. In conclusion, ground cover in peach orchards supported the enemies hypothesis, as indicated by the fact that ground cover T. repens promoted the abundance and diversity of predators and reduced the number of arthropod pests in tree canopies in both geographical areas.

  13. Testing the enemies hypothesis in peach orchards in two different geographic areas in eastern China: the role of ground cover vegetation.

    Science.gov (United States)

    Wan, Nian-Feng; Ji, Xiang-Yun; Jiang, Jie-Xian

    2014-01-01

    Many studies have supported the enemies hypothesis, which suggests that natural enemies are more efficient at controlling arthropod pests in polyculture than in monoculture agro-ecosystems. However, we do not yet have evidence as to whether this hypothesis holds true in peach orchards over several geographic locations. In the two different geographic areas in eastern China (Xinchang a town in the Shanghai municipality, and Hudai, a town in Jiangsu Province) during a continuous three-year (2010-2012) investigation, we sampled arthropod pests and predators in Trifolium repens L. and in tree canopies of peach orchards with and without the ground cover plant T. repens. No significant differences were found in the abundances of the main groups of arthropod pests and predators in T. repens between Hudai and Xinchang. The abundance, richness, Simpson's index, Shannon-Wiener index, and Pielou evenness index of canopy predators in ground cover areas increased by 85.5, 27.5, 3.5, 16.7, and 7.9% in Xinchang, and by 87.0, 27.6, 3.5, 17.0 and 8.0% in Hudai compared to those in the controls, respectively. The average abundance of Lepidoptera, Coleoptera, Homoptera, true bugs and Acarina canopy pests in ground cover areas decreased by 9.2, 10.2, 17.2, 19.5 and 14.1% in Xinchang, and decreased by 9.5, 8.2, 16.8, 20.1 and 16.6% in Hudai compared to that in control areas, respectively. Our study also found a higher density of arthropod species resources in T. repens, as some omnivorous pests and predators residing in T. repens could move between the ground cover and the orchard canopy. In conclusion, ground cover in peach orchards supported the enemies hypothesis, as indicated by the fact that ground cover T. repens promoted the abundance and diversity of predators and reduced the number of arthropod pests in tree canopies in both geographical areas.

  14. Effect of the sowing date and agrotextile covering on the growth and length of vegetation period of sweet corn cultivated in the conditions of eastern Poland

    Directory of Open Access Journals (Sweden)

    Robert Rosa

    2013-12-01

    Full Text Available An experiment was conducted from 2006 to 2008 to examine the effect of three sowing dates and covering of soil with agrotextile on the length of sweet corn growing season and corn growth. When sweet corn sowing date was delayed from late April to late May, the growing season was shortened, the extent of this shortening being conditioned by the weather conditions in the study years. The growing season was much shorter in warmer years and a little shorter in a cold year. Covering with agrotextile at the first (26th April and second (10th May sowing date accelerated cob harvest by eight days. When seeds were sown at the third date (24th May, cobs were harvested five days earlier. Sweet corn plants grew better in colder versus warmer years. The greatest number of cobs per plant was formed when the weather was warmer and precipitation was evenly distributed. In warmer years, delayed sowing contributed to a lower number of cobs whereas in the colder year the opposite response was observed. Compared with a hot and dry year, significantly higher marketable tuber yields were harvested in a warm year characterized by evenly distributed precipitation and in a colder and wet year. The marketable cob yields of sweet corn sown on the 10th May were significantly higher compared with the 26th of April. Covering with agrotextile contributed to a significantly higher number of cobs per plant, and increased marketable cob yields, too.

  15. Efeito de diferentes coberturas vegetais e sistemas de preparo do solo na produção da cultura da soja = Effect of different vegetal coverings and soil tillage systems on soybean crop production

    Directory of Open Access Journals (Sweden)

    Reny Adilmar Prestes Lopes

    2007-10-01

    Full Text Available Este trabalho avaliou o desempenho da soja sob a influência de cobertura vegetal e de manejo do solo em um Latossolo Vermelho distrófico. Utilizaram-se aveia, nabo, ervilhaca, ervilha, milheto e tremoço. Avaliaram-se altura e densidade de plantas, altura de inserção de vagens, número de vagens, produtividade, massa de mil grãos, teor de água, densidade e resistência do solo à penetração. O sistema semeadura direta teve maior altura de inserção de vagens, quantidade de vagens, altura de plantas, teor de água e densidade do solo. Maiores valores de resistência do solo à penetração foram verificados no preparo convencional, porém obteve-se maior produtividade. As coberturas e os sistemas de preparo influenciaram na produtividade das plantas de soja. As coberturas vegetaispromoveram melhorias no solo com redução da compactação em algumas camadas do solo. O consórcio aveia/ervilhaca mostrou-se uma técnica de manejo inadequada para as condições às quais o solo foi submetido. O consórcio aveia/milheto mostrou ser uma opção viável de cobertura de solo antecessora à soja. A semeadura direta mostrou ser técnica demanejo adequado para o tipo de solo estudado.This study evaluated the performance of the soybean under the influence of vegetal covering and soil management in Red Latosol dystrofic. Oats, turnip, hairy vetch, pea, millet and lupine were used. The study evaluated height and density of plants, height of insertion in string beans, number of string beans, productivity, athousand grain mass, water contend, bulk density and soil resistance to penetration. The no-tillage system had greater height of insertion of string beans, amount of string beans, height of plants, water contend and soil bulk density. Greater values of soil resistance topenetration were verified in the tillage, though higher productivity was observed. The coverings and the soil tillage systems influenced the productivity of soybean plants. The

  16. EFEITO DA COBERTURA VEGETAL DO SOLO SOBRE A ABUNDÂNCIA E DIVERSIDADE DE INIMIGOS NATURAIS DE PRAGAS EM VINHEDOS EFFECTS OF COVER CROPS ON THE ABUNDANCE AND DIVERSITY OF NATURAL ENEMIES OF GRAPEVINE PEST

    Directory of Open Access Journals (Sweden)

    MARCOS ANTÔNIO MATIELLO FADINI

    2001-12-01

    Full Text Available O controle de pragas da videira no Brasil restringe-se basicamente ao uso de inseticidas, devido à inexistência de trabalhos que visem a complementar o manejo de pragas através de controle biológico. Neste trabalho, objetivou-se verificar o efeito de diferentes coberturas vegetais nas entrelinhas de plantio de videira sobre a abundância e diversidade de potenciais inimigos naturais de pragas da videira no município de Caldas, região Sul do Estado de Minas Gerais. Foram testadas sete diferentes coberturas de solo (aveia-preta, aveia-preta e ervilhaca, ervilhaca, cobertura morta, uso de herbicida, capina mecânica e mato roçado. A cobertura vegetal do solo influenciou tanto a diversidade quanto a abundância de inimigos naturais, sendo o consórcio de aveia-preta e ervilhaca, cultivadas simultaneamente, o tratamento que proporcionou maior diversidade e abundância de inimigos naturais. Assim, a cobertura vegetal do solo pode, potencialmente, ser um componente importante em programas de manejo integrado de pragas na cultura da videira.The control of grapevine pests in Brazil is only based in the use of chemical products. It is due to the whole absence of experimental works developed to test and evaluate alternative control systems, like the biological control. The objective of this work was to evaluate the effect of different types of cover crops, placed between the cultivation lines of grapevine, in the abundance and diversity of natural control arthropods of grapevine pests. The experiment was conduced in the EPAMIG, Caldas Research Farm, located in the Minas Gerais State, Brazil. They Were tested seven different systems of soil covering. The presence of vegetal covering was beneficial to improve the diversity as well as the abundance of biological control agents present on the grapevine crop. The cultivation of black oat and pea together, was the treatment that showed the better result to diversity and abundance. Therefore, the cover

  17. Mapeamento da antiga cobertura vegetal de várzea do Baixo Amazonas a partir de imagens históricas (1975-1981 do Sensor MSS-Landsat Mapping ancient vegetation cover of the Amazon floodplain using historical MSS/Landsat images (1975-1981

    Directory of Open Access Journals (Sweden)

    Vivian Fróes Renó

    2011-03-01

    -classification techniques. The resulting map was organized four classes of land cover types: floodplain forest, non-forest floodplain vegetation, bare soil, and open water. Map accuracy was estimated from two types of ground data 1 sample points describing ground cover classes not subjected to major changes, such as permanent water bodies, and identifying indicators of the 30 year old vegetation type landscape (72 points; 2 interviews with community early residents for memory recovery of information on the vegetation cover existing in the 1970 (44 interviews. Altogether, 116 information points was collected along the study area. These points were used to calculate the Kappa Index for agreement between the four field-verified classes and the automatic classification, with value (0.78 indicates the good quality of the floodplain vegetation cover map. The region had 8650 km2 coverage of floodplain forest at the time of image acquisition.

  18. Pollen-inferred quantitative reconstructions of Holocene land-cover in NW Europe for the evaluation of past climate-vegetation feedbacks - The Swedish LANDCLIM project and the NordForsk LANDCLIM network

    Science.gov (United States)

    Gaillard, Marie-Jose; Sugita, Shinya; Rundgren, Mats; Smith, Benjamin; Mazier, Florence; Trondman, Anna-Kari; Fyfe, Ralph; Kokfelt, Ulla; Nielsen, Anne-Birgitte; Strandberg, Gustav

    2010-05-01

    Reliable predictive models are needed to describe potential future climate changes and their impacts. Land surface-atmosphere feedbacks and their impacts on climate are a current priority in the climate modelling community, but reliable records of long-term land use and vegetation change required for model evaluation are limited. Palaeoecological and palaeo-climatic data provide a unique record of the past changes in vegetation, land use and climate on time scales relevant to vegetation processes and global change projections. The application of a new technique (the REVEALS model (Sugita 2007) to landscape reconstruction using fossil pollen data makes robust comparisons with vegetation model output possible . The model corrects for biases caused by e.g. inter-taxonomic differences in pollen productivity and dispersal. Our results show that pollen percentages, a traditional indicator of land cover changes, generally underestimate the unforested areas and certain broad-leaved trees such as Corylus and Tilia, while they often overestimate Betula and Pinus (see Cui et al. BG 6.2). Climate models use simplified land-surface classifications (plant functional types (PFTs)), such as grass (i.e. open land), deciduous trees, and conifers. Therefore, the observed large discrepancies in past land cover between the REVEALS estimates and pollen percentages are expected to influence model outcomes of the Holocene regional climate in NW Europe. The LANDCLIM project and research network (sponsored by the Swedish [VR] and Nordic [NordForsk] Research Councils) aim to quantify human-induced changes in regional vegetation/land-cover in NW Europe during the Holocene, and to evaluate the effects of these changes on the regional climate through altered feedbacks. We use the REVEALS model, theoretically derived and empirically tested, to estimate the percentage cover of taxa and groups of taxa (PFTs) from fossil pollen data for selected time windows of the Holocene, at a spatial resolution

  19. An Automatic Extraction Approach to Fractional Vegetation Cover of Saline Land with Digital Images%吉林西部盐碱地数字图像植被覆盖度的自动提取

    Institute of Scientific and Technical Information of China (English)

    丁艳玲; 赵凯; 李晓峰; 郑兴明

    2013-01-01

      植被覆盖度是生态环境变化的重要指标,也是遥感反演的关键参数。盐碱地植被覆盖度的准确测量对研究地表植被蒸腾、土壤水分蒸发及土壤退化、盐碱化等具有重要意义。过绿指数(Excess Green index,ExG)对绿色植被比较敏感,能突显植被信息,去除土壤、阴影的干扰。通过对吉林西部盐碱地玉米、高粱、绿豆、杂草、土壤数字图像特征分析,利用改进过绿指数(Modified Excess Green index,MExG)算法计算植被和土壤的MExG值;并确定区分植被和土壤的MExG阈值为40,进而计算植被覆盖度。本文采用监督分类的最大似然法对比验证MExG自动提取结果,并对两种方法计算的玉米、高粱、绿豆和杂草的覆盖度,分别进行目视判读和t检验。研究表明,MExG自动提取方法具有客观性强,处理时间短,分类精度高等优点,是计算不同植被类型覆盖度的有效方法。%Fractional vegetation cover is an important variable in ecological environment and a key parameter in remote sensing estimation, which is needed in the modeling of the land-atmosphere exchanges of momentum, en-ergy, water, and trace gases. Determination of fractional vegetation cover exactly is necessary for studies on plant transpiration, ground surface evaporation, soil degradation and salinization. Excess green, highlighting veg-etation and inhibiting the interference of soil and shadow, was used as a contrast enhancement for identifying plants from soil regions. This study uses modified excess green index to extract fractional vegetation cover by an-alyzing RGB color features of corn, sorghum, mung beans and weeds growing in saline land in western Jilin Province. The digital images are geometrically corrected in order to eliminate distortion. The automatic extrac-tion approach using modified excess green indexes which is about 40 for vegetation growing on the saline land of western

  20. Exatidão de posicionamento de um receptor GPS, operando sob diferentes coberturas vegetais Evaluation of the accuracy of positioning a GPS receiver operating under different vegetation covers

    Directory of Open Access Journals (Sweden)

    Rubens Angulo Filho

    2002-01-01

    Full Text Available Para avaliar a exatidão de posicionamento planimétrico do receptor GPS Trimble/Pro-XL, operando sob diferentes condições de cobertura vegetal (pastagem, seringueira, eucalipto e pinus, o equipamento foi posicionado alternadamente sobre 6 pontos, locados ao acaso nas áreas de estudo, variando o tempo de permanência (1 , 5 e 10 min mas com a mesma taxa de aquisição de dados (1 s fazendo-se, posteriormente, a correção diferencial (DGPS pós-processada dos dados. Os pontos também tiveram suas coordenadas levantadas pelo método topográfico, segundo a NBR 13133 - Execução de Levantamento Topográfico, para fins de comparação. De acordo com o método empregado e os resultados obtidos, foi possível separar as exatidões de posicionamento planimétrico, conforme o tipo de cobertura vegetal, em dois grupos: sem e com cobertura arbórea confirmando, assim, a interferência do dossel na recepção dos sinais emitidos pelos satélites GPS. O aumento do tempo de permanência melhorou a exatidão de posicionamento planimétrico, o que ratifica a escolha da metodologia de levantamento como sendo fundamental para a obtenção de bons resultados de posicionamento.To evaluate planimetric positioning accuracy of a GPS receiver (Trimble/Pro-XL, operating under different conditions of vegetation cover (pasture, rubber trees, eucalyptus and pine trees, 6 control points were located randomly in the study area. For comparison, their coordinates were first obtained by a conventional surveying method, according to NBR 13133 of Brazilian Surveying Standards. Afterwards, the GPS receiver was positioned on those control points, maintaining the acquisition rate of 1 s while changing the time for 1, 5 and 10 min, the DGPS method was used to correct the positioning coordinate data. According to the methodology applied and the results obtained, it was possible to distinguish planimetric positioning accuracy, according to the vegetation cover, in two groups

  1. Landscape change in the Holocene transition Development of a predictive model of vegetation cover in the Asón Valley (Cantabria

    Directory of Open Access Journals (Sweden)

    García Moreno, Alejandro

    2007-12-01

    Full Text Available The spatial distribution of prehistoric vegetation, and its evolution during the Pleistocene-Holocene transition, is essential for understanding the changes in the settlement patterns that took place at the end of the Upper Palaeolithic. To calculate this distribution, we have use a predictive model based on the weighted values method, according to the forest vegetation’s ecological requirements, analizing its evolution in the Asón river valley (Cantabria and its relationship with Palaeolithic sites.

    El conocimiento de la distribución espacial de la vegetación prehistórica, y su evolución a lo largo de la transición al Holoceno, es fundamental para entender los cambios en los patrones de explotación del territorio y de asentamiento que se producen en los grupos de cazadores-recolectores del final del Paleolítico Superior. Para calcular dicha distribución, se emplea un modelo predictivo basado en el método de weighted values (valores ponderados, a partir de los requerimientos ecológicos de la vegetación arbórea, analizando su evolución en el Valle del Asón (Cantabria y su relación con los yacimientos paleolíticos que allí existen.

  2. Physicochemical and biological characteristics of coastal saline soft under different vegetation cover%种植条件下海滨盐土理化性状与生物学特征

    Institute of Scientific and Technical Information of China (English)

    李刚; 周建; 钦佩

    2011-01-01

    以苏北海滨盐土种植实验区7个不同特征的地块为对象,研究了海滨盐土基本理化性状及其生物学特征的季节变化,以及其与植物种植和植被条件的关系.结果表明:海滨盐土的土壤性状随种莓年限和植被状况的不同有较大的变异性,种植耐盐植物地块平均土壤电导率(0.95 dS·m-1)低于自然植被地块(2.77 dS·m-1),但部分地块电导率水平较种植前有所升高;土壤肥力普遍较低,水解性氮含量平均低于50 mg·kg-1,有效磷含量(除施肥地块)平均低于3 mg·kg-1,有机质含量低于1%,种植耐盐植物地块因施肥而有所改善.土壤电导率和养分水平是影响盐土植被生长与分布的主要因素,前者尤为关键;土壤氮磷含量与微生物数量密切相关.不同植被和干扰状况下土壤性状的季节变化差异明显,植被盖度高、人为干扰少的土壤环境相对稳定,反之则波动剧烈.%Taking seven plots of coastal saline soil under different vegetation cover in North Jiangsu as study sites, this paper studied the seasonal fluctuations of soil basic physicochemical and biological characteristics, and analyzed the relationships between these fluctuations and vegetation cover.In the test plots, there was a greater variability of soil basic physicochemical and biological characteristics. The average soil electrical conductivity was lower in crop plots (0.95 dS · m-1) than in natural vegetation plots ( 2.77 dS·m-1 ) . but parts of the crop plots showed an increased soil electrical conductivity compared with pre-planting. Overall. the soil fertility of the plots was generally at a low level. with the hydrolysable nitrogen content averagely lower than 50 mg · kg-1, available phosphorus content ( except fertilized plots) lower than 3 mg·kg-1 , and organic matter content less than l%. Due to fertilization. the soil conditions in crop plots somewhat improved. For the test coastal saline soil. its electrical

  3. Nitrogen fixation in seedlings of sabia and leucena grown in the caatinga soils under different vegetation covers; Fixacao de nitrogenio em mudas de sabia e leucena cultivadas em solos da caatinga sob diferentes coberturas vegetais

    Energy Technology Data Exchange (ETDEWEB)

    Santana, Augusto Cesar de Arruda; Nascimento, Luciana Remigio Santos; Silva, Arthur Jorge da; Freitas, Ana Dolores Santiago de, E-mail: augusto.arruda26@yahoo.com.br, E-mail: lucaremigio@yahoo.com.br, E-mail: arthur.floresta.jorge@gmail.com, E-mail: ana.freitas@depa.ufrpe.br [Universidade Federal Rural de Pernambuco (UFRPE), Recife, PE (Brazil). Departamento de Agronomia

    2013-07-01

    The aim of this study was to evaluate the efficiency differences of populations forming bacteria in legume nodules (BNL) in areas under different vegetation cover in semi-arid Pernambuco state, Brazil, using the methodology of the natural abundance of {sup 15}N to estimate the amount of N fixed symbiotically. The highest levels of nitrogen was found in plants of leucena, and the sabia had levels that did not differ from reference species. The analysis by the technique of 15N showed that in all areas the leucena and the sabia showed signs of 15N different of the average signal of the control plants. The largest nitrogen accumulation was observed for leucena in the Caatinga and Capoeira. The sabia got greater accumulation of N from the Caatinga. The areas of Capoeira and Caatinga has showed the native populations of rhizobia with greater ability to fix nitrogen for the leucena.

  4. Paleogene events in Central Eurasia: their role in the flora and vegetation cover evolution, migration of phytochore boundaries, and climate changes

    Science.gov (United States)

    Akhmetiev, M. A.; Zaporozhets, N. I.

    2014-05-01

    The flora and vegetation of Central Eurasia evolved in the Paleogene to a significant extent in line with the scenario similar to the Late Cretaceous one. The position of high-rank phytochores was controlled by the global climatic zonality, while development stages of the flora depended on interaction between the Arctic and Tethyan water masses and direction of atmospheric flows and were determined by principal geological and paleogeographic events in the Paleogene history of Central Eurasia. Five main stages are definable in development of the Paleogene flora: (1) early-middle Danian with the wide distribution of temperate-thermophilic floras in the middle and high latitudes and their westward and southward expansion from the Pacific and Arctic regions of the Boreal realm; (2) Late Paleocene-Early Eocene with the maximal advancement of the Tethyan flora to the high latitudes and northward migration of phytochore boundaries in response to intense water exchange between the Tethys and Atlantic oceans with its trade currents and atmospheric heat transfer directly from the tropical zone in absence of the Alpine-Himalayan orogen; (3) Lutetian with development of subtropical monsoon-type floras under influence of the water mass exchange between the Arctic Basin and Peritethys with the monsoon-induced currents and atmospheric heat transfer from the Peritethys under conditions of the restricted connection between the Central Asia basins and Tethys; (4) (?) late Lutetian-Priabonian reflecting the climate inversion due to isolation of the West Siberian Sea from the Arctic Basin against the background of its continuing connection with the Peritethys; the formation of the semiclosed West Siberian Sea at that time was accompanied by development of a climate with humid winters, hot dry summers, and deficiency of average annual precipitation in the middle latitudes of Central Eurasia, where luxuriant subtropical Quercus-Laurus forests with Castanopsis that prevailed at the

  5. Quantifying the Impacts of Environmental Factors on Vegetation Dynamics over Climatic and Management Gradients of Central Asia

    Directory of Open Access Journals (Sweden)

    Olena Dubovyk

    2016-07-01

    Full Text Available Currently there is a lack of quantitative information regarding the driving factors of vegetation dynamics in post-Soviet Central Asia. Insufficient knowledge also exists concerning vegetation variability across sub-humid to arid climatic gradients as well as vegetation response to different land uses, from natural rangelands to intensively irrigated croplands. In this study, we analyzed the environmental drivers of vegetation dynamics in five Central Asian countries by coupling key vegetation parameter “overall greenness” derived from Moderate Resolution Imaging Spectroradiometer (MODIS Normalized Difference Vegetation Index (NDVI time series data, with its possible factors across various management and climatic gradients. We developed nine generalized least-squares random effect (GLS-RE models to analyze the relative impact of environmental factors on vegetation dynamics. The obtained results quantitatively indicated the extensive control of climatic factors on managed and unmanaged vegetation cover across Central Asia. The most diverse vegetation dynamics response to climatic variables was observed for “intensively managed irrigated croplands”. Almost no differences in response to these variables were detected for managed non-irrigated vegetation and unmanaged (natural vegetation across all countries. Natural vegetation and rainfed non-irrigated crop dynamics were principally associated with temperature and precipitation parameters. Variables related to temperature had the greatest relative effect on irrigated croplands and on vegetation cover within the mountainous zone. Further research should focus on incorporating the socio-economic factors discussed here in a similar analysis.

  6. Effects of fire and three fire-fighting chemicals on main soil properties, plant nutrient content and vegetation growth and cover after 10 years.

    Science.gov (United States)

    Fernández-Fernández, M; Gómez-Rey, M X; González-Prieto, S J

    2015-05-15

    The study addresses a knowledge-gap in the long-term ecological consequences of fire and fire-fighting chemicals. Ten years after a prescribed fire and the application of three fire-fighting chemicals, their effects on the soil-plant system were evaluated. Five treatments were established: unburnt soils (US) and burnt soils treated with water alone (BS), foaming agent (BS+Fo), Firesorb (BS+Fi) and ammonium polyphosphate (BS+Ap). Soils (0-2 cm depth) and foliar material of shrubs (Erica umbellata, Pterospartum tridentatum and Ulex micranthus) and trees (Pinus pinaster) were analysed for total N, δ(15)N, and soil-available and plant total macronutrients and trace elements. Soil pH, NH₄(+)-N and NO₃(-)-N; pine basal diameter and height; and shrub cover and height were also measured. Compared with US plots, burnt soils had less nitrates and more Mo. Although differences were not always significant, BS+Ap had the highest levels of soil available P, Na and Al. Plants from BS+Ap plots had higher values of δ(15)N (P. pinaster and E. umbellata), P (all species), Na (P. tridentatum and U. micranthus) and Mg (E. umbellata and P. tridentatum) than other treatments; while K in plants from BS+Ap plots was the highest among treatments for P. pinaster and the lowest for the shrubs. Pines in US plots were higher and wider than in burnt treatments, except for BS+Ap, where the tallest and widest trees were found, although half of them were either dead (the second highest mortality after BS+Fi) or had a distorted trunk. BS+Ap was the treatment with strongest effects on plants, showing E. umbellata the lowest coverage and height, P. tridentatum the highest coverage, U. micranthus one of the lowest coverages and being the only treatment where Genista triacanthos was absent. Consequently, it is concluded that both fire and ammonium polyphosphate application had significant effects on the soil-plant system after 10 years.

  7. Effects of fire and three fire-fighting chemicals on main soil properties, plant nutrient content and vegetation growth and cover after 10 years

    Energy Technology Data Exchange (ETDEWEB)

    Fernández-Fernández, M., E-mail: mariafernandez@iiag.csic.es; Gómez-Rey, M.X., E-mail: mxgomez@iiag.csic.es; González-Prieto, S.J., E-mail: serafin@iiag.csic.es

    2015-05-15

    The study addresses a knowledge-gap in the long-term ecological consequences of fire and fire-fighting chemicals. Ten years after a prescribed fire and the application of three fire-fighting chemicals, their effects on the soil–plant system were evaluated. Five treatments were established: unburnt soils (US) and burnt soils treated with water alone (BS), foaming agent (BS + Fo), Firesorb (BS + Fi) and ammonium polyphosphate (BS + Ap). Soils (0–2 cm depth) and foliar material of shrubs (Erica umbellata, Pterospartum tridentatum and Ulex micranthus) and trees (Pinus pinaster) were analysed for total N, δ{sup 15}N, and soil-available and plant total macronutrients and trace elements. Soil pH, NH{sub 4}{sup +}–N and NO{sub 3}{sup −}–N; pine basal diameter and height; and shrub cover and height were also measured. Compared with US plots, burnt soils had less nitrates and more Mo. Although differences were not always significant, BS + Ap had the highest levels of soil available P, Na and Al. Plants from BS + Ap plots had higher values of δ{sup 15}N (P. pinaster and E. umbellata), P (all species), Na (P. tridentatum and U. micranthus) and Mg (E. umbellata and P. tridentatum) than other treatments; while K in plants from BS + Ap plots was the highest among treatments for P. pinaster and the lowest for the shrubs. Pines in US plots were higher and wider than in burnt treatments, except for BS + Ap, where the tallest and widest trees were found, although half of them were either dead (the second highest mortality after BS + Fi) or had a distorted trunk. BS + Ap was the treatment with strongest effects on plants, showing E. umbellata the lowest coverage and height, P. tridentatum the highest coverage, U. micranthus one of the lowest coverages and being the only treatment where Genista triacanthos was absent. Consequently, it is concluded that both fire and ammonium polyphosphate application had significant effects on the soil–plant system after 10 years

  8. Qualidade da água em microbacias hidrográficas com diferentes coberturas do solo no sul do Espírito Santo Water quality in watersheds with diferent vegetal cover in southern Espirito Santo state, Brazil

    Directory of Open Access Journals (Sweden)

    Ana Paula Almeida Bertossi

    2013-02-01

    Full Text Available O objetivo deste trabalho foi avaliar a qualidade das águas superficiais e subterrâneas em microbacias hidrográficas caracterizadas por diferentes coberturas do solo: pastagem, floresta e cafeeiro. Foi desenvolvido um índice de qualidade de água utilizando a análise de componentes principais, que proporcionou a redução das 13 características de qualidade em duas componentes, que explicaram 91,2% da variância total. As águas superficiais e subterrâneas das microbacias foram adequadas ao consumo humano, após tratamento convencional, ao longo de todo o período estudado, exceto a água subterrânea da microbacia coberta com pastagem no período de estiagem.The objective of this work was to evaluate the quality of surface water and groundwater in watersheds characterized by different vegetal cover: pasture, forest and coffee crops. It was developed a water quality index by using the analysis of the main components, which provided the reduction of 13 quality features into two components that explained 91.2% of the total variance. Surface water and groundwater of the watersheds were suitable for human consumption after conventional treatment over the studied period, except the groundwater of watershed covered with pasture in the dry season.

  9. Environmental impact of almond crop in strong slope with two vegetable covers: bush and leguminous; Impacto en el medio ambiente del cultivo de almendros en fuertes pendientes con dos cubiertas vegetales: Matorral y Leguminosa

    Energy Technology Data Exchange (ETDEWEB)

    Carceles Rodriguez, B.; Francia Martinez, J. R.; Martinez Raya, A.

    2009-07-01

    Soil erosion is one of the main physical processes of land degradation in Spain. Several studies in the Mediterranean environment have demonstrated the positive effect of vegetation covers on the reduction of water erosion and their indirect improvement of the soil physical and chemical properties, essentially by the incorporation of organic matter. Sol loss and surface runoff patterns over a four-year period were monitors in erosion plots from hill slope with two different cover-crop strips: (1) non-tillage with leguminous (Lens esculenta Moench) and (2) non-tillage with and a mixture of autochthonous thymes (Thymus baeticus Boiss. ex Lacaita, Thymus capitatus (L) Hoffmanns and Link., Thymus vulgaris L.) of 3 m with, in Lanjaron (Granada) on the south flank of the Sierra Nevada of southeast Spain. The erosion plots were located on the hill slope at 35% incline, at 580 m in altitude and with 144 m{sup 2} (24 m x 6 m) in area. the area selected for the experiment is the part of the rainfed orchard given entirely with almond (Prunus amygdalus Basch cv. Desmayo Largueta) trees, the planting gird were 6 x 7 m. (Author) 10 refs.

  10. GAP Land Cover - Tiled Raster

    Data.gov (United States)

    Minnesota Department of Natural Resources — This raster dataset is a detailed (1-acre minimum), hierarchically organized vegetation cover map produced by computer classification of combined two-season pairs of...

  11. Erosion-Induced Carbon Fluxes from Semiarid Rangelands: Implications of Vegetation Cover and Enrichment Dynamics for Carbon Inputs to Aquatic Systems

    Science.gov (United States)

    Cunliffe, Andrew; Puttock, Alan; Turnbull, Laura; Wainwright, John; Brazier, Richard

    2016-04-01

    Dryland ecosystems are a globally significant of the global carbon cycle. They cover ca. 40% of the land surface, and dominate both the long-term trend and interannual variability in the terrestrial carbon sink. Therefore, developing process-based understanding of carbon dynamics in drylands is essential for understanding terrestrial carbon dynamics globally. This study focuses on the amounts of organic carbon (OC) eroded from semiarid hillslopes. Dryland ecosystems are characteristically susceptible to change. One example of this is the encroachment of woody shrubs into former grasslands, substantially altering the structure and function of these landscapes. We established four, 30 x 10 m runoff plots across an ecotone from grass- to shrub dominated landscapes, which we monitored during natural rainstorm events over four monsoon seasons. The OC fluxes associated with the eroded sediment were analysed, yielding detailed information on the lateral efflux of OC from these hillslopes. Previous monitoring by our group has demonstrated that production of dissolved OC from these dryland soils is very low. Erosion-induced effluxes of OC were found to systematically increase across the grass-shrub ecotone, resulting in six-fold increases in event-average OC fluxes. The increases were caused by to changes in both erosion rates (three and a half-fold increase) and OC enrichment (almost two-fold increase). Eroded sediments were enriched in OC by up to an order of magnitude, and OC enrichment was a persistent phenomenon. Systematic differences in OC enrichment between different plant functional types in unmanaged ecosystems have not been examined closely in previous work. Together, these findings suggest that (i) failing to consider OC enrichment risks substantially underestimating the input of OC to aquatic systems, and (ii) given the magnitude of systematic differences observed between different plant functional types, attempting to represent OC enrichment via a single

  12. Cobertura vegetal do Estado de São Paulo: II - Levantamento por fotointerpretação das áreas cobertas com floresta natural e reflorestamento Vegetal cover of the State of São Paulo: II - Survey of the forested and reforested areas through photointerpretation

    Directory of Open Access Journals (Sweden)

    Mário Borgonovi

    1967-01-01

    Full Text Available É apresentado o levantamento por fotoínterpretação da cobertura vegetal de floresta natural e reflorestamento no Estado de São Paulo, Brasil. O trabalho foi feito pelo método estatístico de amostragem sistemática, utilizando-se templetos com sinais indicadores dos pontos a serem examinados. Foram interpretados, para a área do Estado de São Paulo, 915.570 pontos, representando cada um 27,15 ha. A área com floresta natural foi de 3.405.800 ha, e com reflorestamento, de 372.9000 ha, representando respectivamente 13,70% e 1,50% da área total do Estado.The present paper refers to the survey of the vegetal cover characterized as forests and as reforested areas in the State of São Paulo, Brazil. This was obtained directly on mosaics, thourgh photointerpretation, using when necessary the aerial vertical photos from the aerophotogrammetric survey of the State of São Paulo done in 1962. In the characterization of forests, the height and density of the trees were taken into consideration, describing the texture of the type of covers on the photos with sampling of fields. In a similar way this was done for reforested areas, also taking into account the factors of formation of areas covered with trees destined to activities connected with silviculture with uniform characterization in regard to the photographic structure. The work was done by means of a systematic sampling method, using templets indicating points to be examined. For the area of São Paulo, 915,570 points were interpreted, each one representing 27.15 ha. Results obtained were the following; forests 3,405,900 ha and reforested areas 372,900 ha, this corresponding respectively to 13.70 and 1.50% of the total area of the State.

  13. Influência da cobertura vegetal do solo na qualidade dos frutos de videira 'Niagara Rosada' Influence of soil cover with grass and leguminous plants on fruit characteristics of table grape variety Niagara Rosada

    Directory of Open Access Journals (Sweden)

    Elaine Bahia Wutke

    2005-12-01

    Full Text Available Devido ao aumento no custo de produção com a utilização de cobertura morta com capim nas ruas da videira 'Niagara Rosada' e à dificuldade para sua aquisição, objetivou-se a possibilidade de substituí-la por plantas de cobertura intercalares. Em experimentos realizados em Indaiatuba e Jundiaí-SP, de 1999-2000 a 2003-2004, instalaram-se seis tratamentos nas entrelinhas, em blocos ao acaso e quatro repetições, constando de área no limpo; vegetação espontânea roçada; cobertura com capim seco de Brachiaria decumbens; cobertura verde de aveia preta (Avena strigosa; cobertura verde de chícharo (Lathyrus sativus; cobertura verde de tremoço (Lupinus albus, de março a outubro, seguidas de cobertura verde de mucuna anã (Mucuna deeringiana de outubro a março. Determinaram-se massa, comprimento e largura do cacho, engaço e bagas, número total de bagas por cacho e diâmetro do pedicelo de bagas, comparando-se os valores médios pelo teste de Duncan ao nível de 5%. Na média dos anos, os resultados com a cobertura verde foram similares ou mais favoráveis que os da cobertura com braquiária seca, podendo-se substituí-la por coberturas vegetais intercalares com gramínea e leguminosas, o ano todo, sem interferência negativa na qualidade comercial dos frutos.Grape vineyard in Southern Brazil utilize a large amount of mulch during autumn-winter season demanding extra efforts and costs, being its acquisition very difficult nowadays. In order to evaluate the possibility of replacing the tradicionally mulch by green cover species in the inter-row strip, two experiments were carried out in Indaiatuba and Jundiaí, SP, Brazil, from 1999/00 to 2003/04, with the table variety Niagara Rosada. The experimental design was a randomized block with four replications and six treatments: 1 no weeded area; 2 cut spontaneous local vegetation; 3 mulch of Brachiaria decumbens; 4 green cover of Avena strigosa from March to October followed by green cover of

  14. Caracterização das perdas e distribuição de cobertura vegetal em colheita mecanizada de soja Characterization of losses and crop residue cover distribution in soybean mechanized harvest

    Directory of Open Access Journals (Sweden)

    Anderson de Toledo

    2008-12-01

    Full Text Available O conceito de controle de qualidade nas operações inserido na agricultura é viabilizado por incidir diretamente nos principais objetivos do processo produtivo: retorno econômico e aumento da produtividade. A colheita mecanizada normalmente é realizada sem que haja controle efetivo para que a variabilidade das perdas fique dentro de padrões aceitáveis. Esta pesquisa teve o objetivo de determinar e caracterizar as perdas e a distribuição da cobertura vegetal após a colheita mecanizada da soja, por meio de ferramenta de controle estatístico de processo (cartas de controle. A média da perda de grãos total foi próxima do limite superior aceitável para a cultura da soja, apresentando alta variabilidade entre os pontos, tornando o processo fora de controle. A distribuição de cobertura vegetal manteve-se em processo controlado, com maior variabilidade onde o relevo foi mais inclinado. A utilização das cartas de controle foi eficiente na identificação dos pontos fora de controle e na avaliação da qualidade do processo de colheita.The concept of operation control inserted in agriculture is made possible by making a directly influence in the main objectives of productive process, economic return and increase of productivity. The mechanized harvest normally is carried out without an effective control of the variability of losses so that it maintains acceptable standards. This research aimed to determinate and characterize the losses and crop residue cover distribution after soybean mechanized harvest, using the tool of statistical process control (control charts. The average of total grain losses was near the upper limit specified for losses in soybean, showing high variation between points, and putting the process out of control. The residue crop cover distribution stayed under control process, with greater variability where the terrain was more sloping. The use of control charts was efficient to identify the points out of control

  15. Land Cover

    Data.gov (United States)

    Kansas Data Access and Support Center — The Land Cover database depicts 10 general land cover classes for the State of Kansas. The database was compiled from a digital classification of Landsat Thematic...

  16. Deposition of sandstorms in a vegetation-covered sand dune in Ejin Oasis and its characteristics%额济纳绿洲沙尘暴沉积特征

    Institute of Scientific and Technical Information of China (English)

    温小浩; 李保生; 王为

    2006-01-01

    "Ejin Section" found in a typical vegetation-covered sand dune in Ejin Oasis was investigated. In this study, 263 samples were taken from the section for grain-size analysis, 25 for chemical analysis, 11 for 14C dating and 6 for scanning electron microscope (SEM). The results of the study indicate that 3 types of the sediments in the section can be identified, YS, LS and ST. YS, homogeneous yellow-brown dune sands, is equal to those of inland deserts, LS, loess-like sandy soils, is the same as the sandy loess in the middle Yellow River and modern falling dusts, and ST, sandy sediments interbeded with the deadwood and defoliation of Tamarix spp, represents the depositional process of the section interrupted by abrupt changes in climate. The Ejin Section has recorded the repeated dust-storms or sandstorms since 2500 yr BP and the peak periods of the dust-storms or sandstorms revealed by the section are consistent with the records of "dust rains" in historical literatures, indicating that the change of climate is a key factor to increase sandstorms or dust-storms, whereas, "artificial" factor may only be an accelerating one for desertification.

  17. Cover crop with Teramnus labialis in a citrus orchard: effects on some physical properties of the soil / Cubierta vegetal con Teramnus labialis en plantaciones citrícolas: efectos sobre algunas propiedades físicas del suelo Cubierta vegetal con Teramnus labialis en plantaciones citrícolas: efectos sobre algunas propiedades físicas del suelo

    Directory of Open Access Journals (Sweden)

    Leydis Castellano Rodríguez

    2009-03-01

    Full Text Available The use of leguminous cover crops in citrus orchards constitutes a viable alternative for the improvement of soil properties, whenever they are appropriately managed. In Ciego de Avila University, Cuba, it was evaluated the effect of a leguminous cover crop on some properties of an orchard soil. The work was carried out during four years in an orange plantation of Valencia late (Citrus sinensis L. Osbeck in a 22 years-old orchard, with a plantation frame of 8 X 4 m, planted on a typical red Ferralitic soil, belonging to the CPA ¨José Martí¨, in Ciego de Avila. It was used a random block design with three treatments: one with covering of Teramnus labialis (T1, one with expontaneous vegetation (T2 and the third with no vegetation (T3. The functional structure properties of the soil were determined, and also the composition of macroaggregates expressed in the structure coefficient and the percentage of stable added in water, soil density, humidity and porosity. The increments in the humidity of the soil, the specific volume of pores and air, the structure coefficient, as well as the percentage of stable added in water, in the soil where the covering of Teramnus labialis was stablished, show the efficiency of cover crops in these citrus orchards.El uso de coberturas vivas de leguminosas en plantaciones citrícolas constituye una alternativa viable para el mejoramiento de las propiedades de los suelos, siempre que ellas se manejan adecuadamente en estas áreas. En la universidad de Ciego de Ávila, Cuba se viene trabajando en la evaluación del efecto de coberturas vivas de leguminosas en plantaciones citrícolas en producción, con el objetivo de evaluar el efecto que ejerce la cobertura de leguminosa sobre algunas propiedades del suelo. El trabajo se realizó durante cuatro años (2001-2005 en una plantación de naranja Valencia Late ( Citrus sinensis L. Osbeck en producción de 22 años, con marco de plantación de 8 X 4 m, plantada sobre un

  18. Atributos biológicos do solo sob influência da cobertura vegetal e do sistema de manejo Soil biological attributes influenced by cover crops and management systems

    Directory of Open Access Journals (Sweden)

    Mozaniel Batista da Silva

    2007-12-01

    Full Text Available O objetivo deste trabalho foi avaliar os efeitos de culturas de cobertura e dos sistemas plantio direto (PD e convencional (PC sobre indicadores biológicos do solo, cultivado com feijoeiro-comum, no inverno, sob irrigação. O experimento foi conduzido em Santo Antônio de Goiás, GO, em Latossolo Vermelho distrófico textura argilosa. Culturas de cobertura foram implantadas anualmente no verão, desde 2001, sendo utilizadas a braquiária, guandu, milheto, capim-mombaça, sorgo, estilosantes, braquiária consorciada com milho, e mata nativa, como tratamento referência. Em 2005, 60 dias após o corte das culturas de cobertura foi implantada a cultura do feijoeiro, cultivar BRS Valente, sob irrigação, com semeadura realizada em 16/6/2005 e colheita efetuada em 19/9/2005. Coletaram-se amostras de solo, na profundidade de 0-10 cm, em três épocas: novembro de 2004 (pré-plantio das culturas de coberturas, junho (pré-plantio do feijoeiro e julho (florescimento do feijoeiro de 2005. Avaliaram-se a respiração basal, o carbono e o nitrogênio da biomassa microbiana, a razão carbono da biomassa microbiana/carbono orgânico, a razão nitrogênio da biomassa microbiana/nitrogênio total e o quociente metabólico do solo. Esses atributos biológicos do solo são influenciados pelas culturas de cobertura, manejo do solo e épocas de amostragem.The objective of this work was to evaluate the effects of cover crops and direct and conventional tillage systems on soil biological attributes when cultivated with dry bean in winter under sprinkle irrigation. The experiment was conducted in Santo Antônio de Goiás, GO, Brazil, in a clayey Rhodic Haplustox. Cover crops were cultivated annually in the summer since 2001, using Brachiaria brizantha, Cajanus cajan, Pennisetum glaucum, Panicum maximum, sorghum, Stylosanthes guianensis, brachiaria in association with corn, and native vegetation as reference. In 2005, 60 days after cutting the cover crops, BRS

  19. CLASIFICACIÓN NO SUPERVISADA DE COBERTURAS VEGETALES SOBRE IMÁGENES DIGITALES DE SENSORES REMOTOS: “LANDSAT - ETM+” NONSUPERVISED CLASSIFICATION OF VEGETABLE COVERS ON DIGITAL IMAGES OF REMOTE SENSORS: "LANDSAT - ETM+"

    Directory of Open Access Journals (Sweden)

    Mauricio Arango Gutiérrez

    2005-06-01

    .The plant species diversity in Colombia and the lack of inventories of them suggests the need for a process that facilitates the work of investigators in these disciplines. Remote satellite sensors such as LANDSAT ETM+ and non-supervised artificial intelligence techniques, such as self-organizing maps - SOM, could provide viable alternatives for advancing in the rapid obtaining of information related to zones with different vegetative covers in the national geography. The zone proposed for the study case was classified in a supervised form by the method of maximum likelihood by another investigation in forest sciences and eight types of vegetative covers were discriminated. This information served as a base line to evaluate the performance of the non-supervised sort keys ISODATA and SOM. However, the information that the images provided had to first be purified according to the criteria of use and data quality, so that adequate information for these non-supervised methods were used. For this, several concepts were used; such as, image statistics, spectral behavior of the vegetative communities, sensor characteristics and the average divergence that allowed to define the best bands and their combinations. Principal component analysis was applied to these to reduce to the number of data while conserving a large percentage of the information. The non-supervised techniques were applied to these purified data, modifying some parameters that could yield a better convergence of the methods. The results obtained were compared with the supervised classification via confusion matrices and it was concluded that there was not a good convergence of non-supervised classification methods with this process for the case of vegetative covers.

  20. Cultivo orgânico sequencial de hortaliças com dois sistemas de irrigação e duas coberturas de solo Successive organic cultivation of vegetable crops in two irrigation systems and two soil covers

    Directory of Open Access Journals (Sweden)

    Roberto BF Branco

    2010-03-01

    Full Text Available Com o aumento da demanda por produtos ecologicamente corretos tornaram-se necessários estudos de novas tecnologias para inseri-las no método de cultivo orgânico para que se tenha um crescimento sustentável da atividade. Neste trabalho avaliou-se o desempenho de cultivares e híbridos de hortaliças cultivados seqüencialmente no método orgânico, em diferentes ambientes. O delineamento experimental foi de parcelas sub-subdivididas com 3 repetições, resultando em 24 unidades experimentais. Foram estudados dois métodos de irrigação (aspersão convencional e localizada por gotejamento; duas coberturas do solo (plástico e palha e dois híbridos ou cultivares de espécies de hortaliças, sendo que para o cultivo do feijão-vagem utilizou-se apenas uma cultivar. Conduziram-se concomitantemente dois cultivos seqüenciais de hortaliças: (1 alface americana - tomate - brócolis e; (2 alface crespa - feijão-vagem - repolho. Avaliaram-se as características produtivas de cada espécie. Na seqüência (1 o cultivo da alface americana teve melhor desempenho quando irrigada por gotejamento, não havendo diferença entre as coberturas do solo, sendo a cv 'Rubette' a mais produtiva. O tomateiro foi mais produtivo no "mulching"plástico, independentemente do método de irrigação e o brócolis teve desempenho semelhante entre os tratamentos. Na seqüência (2 a alface crespa e o feijão-vagem foram mais produtivos quando irrigados por gotejamento e cultivados em cobertura plástica. O repolho teve melhor desempenho na cobertura do solo com filme plástico.With the growing demand for ecological products new technologies are required for organic cultivation systems in order to provide a sustainable growth of this activity. This experiment evaluated the performance of vegetable cultivars and hybrids growing successively in the organic system, in different growth environments. The experimental design was randomized blocks with split split-plots with 3

  1. Pérdidas de suelo y nutrientes bajo diferentes coberturas vegetales en la zona Andina de Colombia Soil and nutrient loss under different vegetation covers in Colombia's Andean region

    Directory of Open Access Journals (Sweden)

    J. Alexander Rodríguez

    2009-07-01

    Full Text Available El estudio se realizó en la reserva natural El Ciprés, ubicada en la vereda Bellavista, municipio de El Dovio (Valle del Cauca. La vereda se encuentra en la zona Andina de la cordillera occidental, en el departamento del Valle del Cauca, entre 1700 y 1800 m.s.n.m., con una temperatura promedio de 18 °C. Según la clasificación climática de Holdridge, corresponde a una zona de bosque húmedo Montano Bajo, con una precipitación promedio entre 2500 y 2700 mm/año, una humedad relativa de 90% y una pendiente del suelo de 62%. Las mediciones se hicieron en parcelas de escorrentía de 32 m² cada una y siete tipos de coberturas: guadua (Guadua angustifolia Kunth, bosque secundario, pastura (Brachiaria decumbens, café (Coffea arabica; banco de proteína (Trichanthera gigantea, caña forrajera (Saccharum officinarum y cultivo limpio conformado por yuca (Manihot esculenta, maíz (Zea mays y arracacha (Arracacia zanthorrhiza Brancroft. Para la evaluación se midieron las pérdidas de suelo y los nutrientes calcio, magnesio, potasio y fósforo en un periodo de 7 meses. Los resultados mostraron diferencias (P Soil and nutrient (calcium, magnesium, potassium, phosphorus losses were measured over a 7-month period in the El Ciprés Natural Reserve, located in the Bellavista rural community, municipality of El Dovio, in the western cordillera of the Andes of the department of Valle del Cauca, Colombia. At 1700-1800 meters above sea level, the area presents an average temperature of 18 °C, an average annual precipitation of 2500-2700 mm, 90% relative humidity, and a 62% slope. According to the Holdridge climate classification system, it corresponds to a lower montane rain forest. Measurements were taken in runoff plots, each 32 m², with seven types of vegetation cover: giant bamboo (Guadua angustifolia Kunth; secondary forest; pastures (Brachiaria decumbens; coffee (Coffea arabica; protein bank (Trichanthera gigantea; forage cane (Saccharum officinarum

  2. 从高光谱卫星数据中提取植被覆盖区铜污染信息%Retrieval of Copper Pollution Information from Hyperspectral Satellite Data in a Vegetation Cover Mining Area

    Institute of Scientific and Technical Information of China (English)

    屈永华; 焦思红; 刘素红; 朱叶青

    2015-01-01

    copper pollution level ,using stepwise multiple linear regression and cross validation on the dataset which is consisting of 44 groups of copper ion content information in the polluted vegetation leaves from Dexing Copper Mine in Jiangxi Province to build up a statistical model by also incorporating the HJ‐1 satellite images .This model was then used to estimate the copper content distribution over the whole research area at Dexing Copper Mine .The result has shown that there is strong statistical significance of the model which revealed the most sensitive waveband to copper ion is lo‐cated at 516 nm .The distribution map illustrated that the copper ion content is generally in the range of 0~130 mg・kg -1 in the vegetation covering area at Dexing Copper Mine and the most seriously polluted area is located at the South‐east corner of Dexing City as well as the mining spots with a higher value between 80 and 100 mg・kg -1 .This result is consistent with the ground ob‐servation experiment data .The distribution map can certainly provide some important basic data on the copper pollution monito‐ring and treatment .%重金属矿山开采活动对生态环境造成了复杂的影响,而植被的生长状况是矿山周围生态环境变化的重要指示因子。常规的对植被中重金属元素富集程度的估计方法往往依赖于大量的野外调查数据以及实验室化学分析方法,需要耗费大量的物力与时间。而通过光谱分析方法能够非接触地获取植被中的重金属含量信息。然而,从高光谱遥感卫星数据中反演植被重金属含量信息仍然是个比较困难的工作。从众多的卫星数据波段中找到对特定重金属元素敏感的波段是植被重金属含量提取的关键。该工作探索了一种基于统计分析的方法从国产卫星(HJ‐1)高光谱数据中实现特征波段发现与重金属含量提取,该方法基于野外实测数据集与环境星高光谱遥感图像

  3. Benthic Cover

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Benthic cover (habitat) maps are derived from aerial imagery, underwater photos, acoustic surveys, and data gathered from sediment samples. Shallow to moderate-depth...

  4. 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...

  5. 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...

  6. 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

  7. Deposição efetiva do produto pulverizado sobre cobertura vegetal de aveia-preta por diferentes pontas de pulverização Effective deposition of product sprayed directly on oat cover using different spray nozzles

    Directory of Open Access Journals (Sweden)

    R.L. Contiero

    2012-12-01

    Full Text Available A cobertura vegetal que permanece no solo após a colheita beneficia as características físicas e químicas do solo. No entanto, essa palha torna-se uma barreira para a aplicação de herbicidas pré-emergentes, pois impede que eles atinjam o alvo. Nesses casos, a escolha ideal da ponta de pulverização, bem como o tamanho da gota, são imprescindíveis para o sucesso da aplicação. O objetivo deste trabalho foi avaliar a eficiência de transposição do líquido pulverizado, dependente do tamanho de gotas, produzido por vários modelos de ponta de pulverização sobre diferentes densidades de palha de aveia-preta. O trabalho foi realizado em Maringá-PR. Foram utilizadas caixas tipo gerbox como unidades coletoras, cobertas por diferentes quantidades de palha de aveia. O delineamento experimental foi inteiramente casualizado, em esquema fatorial 8 x 7, sendo oito pontas de pulverização (leque e cone e sete quantidades crescentes de palha de aveia-preta. O produto retido na superfície coletora foi colhido e mediu-se a absorbância. Os dados foram submetidos à análise de variância, e as médias, comparadas entre si por meio do teste de agrupamento Skott-Knott a 5% de probabilidade. Pode-se concluir que o tamanho das gotas é extremamente importante na transposição da palha de aveia. Gotas muito finas e muito grossas não conseguem transpor a barreira formada pela palha de maneira eficiente. Pontas de pulverização que produzem gotas de tamanho médio (CV-IA 02 e ST 02 apresentam volume de transposição maior do que o das demais, sendo recomendadas em aplicações de herbicidas pré-emergentes em plantio-direto até 4 t ha-1 de cobertura morta.The vegetation that remains in the soil after harvest benefits the physical and chemical properties of soil. However, the straw becomes a barrier to the application of pre-emergence herbicides, preventing it from reaching the target. In these cases, the choice of spray tip and droplet size is

  8. Carbono orgânico e Nitrogênio em agregados de um Latossolo Vermelho distrófico sob duas coberturas vegetais Organic carbon and Nitrogen in aggregates of a Dystrophic Red Latosol under two vegetation covers

    Directory of Open Access Journals (Sweden)

    Renato Ribeiro Passos

    2007-10-01

    tended to present higher contents of COT, NT and NMA. Ratios of C/N, COT/COS and NT/NMA were, on average, higher in aggregates of soils under corn. The NT/NMA ratio was significantly higher in the 15-20 cm layer. However, independent of the soil, the lowest NT/NMA ratios were observed in the smallest aggregate classes, indicating the presence of more labile nitrogen forms. Results showed that vegetation cover type and soil management influenced not only the organic carbon and nitrogen contents, but also organic matter quality. Smaller aggregates are not only responsible for a greater stock of organic matter in the soil but also represent important sites of mineralizable nitrogen. The COS, NMA and the ratios of COT/COS and NT/NMA represent valuable indicators to detect alterations in the lability of organic matter due to management.

  9. Toward a comprehensive landscape vegetation monitoring framework

    Science.gov (United States)

    Kennedy, Robert; Hughes, Joseph; Neeti, Neeti; Larrue, Tara; Gregory, Matthew; Roberts, Heather; Ohmann, Janet; Kane, Van; Kane, Jonathan; Hooper, Sam; Nelson, Peder; Cohen, Warren; Yang, Zhiqiang

    2016-04-01

    Blossoming Earth observation resources provide great opportunity to better understand land vegetation dynamics, but also require new techniques and frameworks to exploit their potential. Here, I describe several parallel projects that leverage time-series Landsat imagery to describe vegetation dynamics at regional and continental scales. At the core of these projects are the LandTrendr algorithms, which distill time-series earth observation data into periods of consistent long or short-duration dynamics. In one approach, we built an integrated, empirical framework to blend these algorithmically-processed time-series data with field data and lidar data to ascribe yearly change in forest biomass across the US states of Washington, Oregon, and California. In a separate project, we expanded from forest-only monitoring to full landscape land cover monitoring over the same regional scale, including both categorical class labels and continuous-field estimates. In these and other projects, we apply machine-learning approaches to ascribe all changes in vegetation to driving processes such as harvest, fire, urbanization, etc., allowing full description of both disturbance and recovery processes and drivers. Finally, we are moving toward extension of these same techniques to continental and eventually global scales using Google Earth Engine. Taken together, these approaches provide one framework for describing and understanding processes of change in vegetation communities at broad scales.

  10. [The role of skin substitutes in the surgical treatment of extensive burns covering more than 60 % of total body surface area. A review of patients over a 10-year period at the Tours University Hospital].

    Science.gov (United States)

    Lamy, J; Yassine, A-H; Gourari, A; Forme, N; Zakine, G

    2015-04-01

    Progress in intensive care and surgery has made it possible to significantly improve the survival of victims with burns over 60% of total body surface area (TBSA). Coverage of the excised areas of these patients can be difficult when there is a shortage of skin donor sites; then the role of skin substitutes can be important. This retrospective study included patients with burns covering more than 60% TBSA and treated at the Tours University Hospital over a period of 10 years. Patients who died during the first week or who presented superficial burns were excluded. The various substitutions means to temporarily or permanently replace the cutaneous barrier are presented. The biological dressings associated with grafts expanded by six according to the sandwich technique, allografts and xenografts, widely expanded postage stamp skin grafts using a modified Meek technique (Humeca(®)), temporary cutaneous substitutes such as Biobrane(®) and skin substitutes colonized by autologous cells (Integra(®)) are presented. Forty-four patients were admitted. Self-immolations represented 52% of the cases. Twenty-one patients were treated with Integra(®), 5 with Biobrane(®), 17 with sandwich grafts and 4 with postage stamp skin grafts. Integra(®) was widely used when donor sites were insufficient. The mean number of surgical procedures per patient was 8.4. The mean duration of hospitalization was 155 days. Twenty-four patients survived until the end of treatment. Eighteen patients died during the first week before any surgery could be performed. Two patients died at the end of treatment. The overall survival rate was 55%. It was 92% for patients who survived the first week. The principal sequel were functional (hand, cervical, thoracic and axillary contractures) and aesthetic (face and hands). Associated treatments were pressotherapy, physical therapy, ergotherapy and thermal water therapy. By temporarily replacing the cutaneous barrier in the absence of sufficient donor sites

  11. Using the Landscape Reconstruction Algorithm (LRA) to estimate Holocene regional and local vegetation composition in the Boreal Forests of Alaska

    Science.gov (United States)

    Hopla, Emma-Jayne; Edwards, Mary; Langdon, Pete

    2016-04-01

    Vegetation is already responding to increasing global temperatures, with shrubs expanding northwards in the Arctic in a process called "greening". Lakes are important features within these changing landscapes, and lake ecosystems are affected by the vegetation in their catchments. Use of dated sediment archives can reveal how lake ecosystems responded to past changes over timescales relevant to vegetation dynamics (decades to centuries). Holocene vegetation changes have been reconstructed for small lake catchments in Alaska to help understand the long-term interactions between vegetation and within lake processes. A quantitative estimate of vegetation cover around these small lakes clarifies the catchment drivers of lake ecosystem processes. Pollen productivity is one of the major parameters used to make quantitative estimates of land cover from palaeodata. Based on extensive fieldwork, we obtained first Pollen Productivity Estimates (PPEs) for the main arboreal taxa in interior Alaska. We used the model REVEALS to estimate the regional vegetation abundance from existing pollen data from large lakes in the region based on Alaskan and European pollen productivity estimates (PPEs). Quantitative estimates of vegetation cover differ from those based on pollen percentages alone. The model LOVE will then be applied to smaller lake basins that are the subject of detailed palaeoliminological investigations in order to estimate the local composition at these sites.

  12. US Forest Service LANDFIRE Potential Vegetation

    Data.gov (United States)

    US Forest Service, Department of Agriculture — LANDFIRE Potential Vegetation is mapped using predictive landscape models based on extensive field-referenced data and biophysical gradient layers using...

  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. Evaluation of MODIS NDVI and NDWI for vegetation drought monitoring using Oklahoma Mesonet soil moisture data

    Science.gov (United States)

    Gu, Y.; Hunt, E.; Wardlow, B.; Basara, J.B.; Brown, J.F.; Verdin, J.P.

    2008-01-01

    The evaluation of the relationship between satellite-derived vegetation indices (normalized difference vegetation index and normalized difference water index) and soil moisture improves our understanding of how these indices respond to soil moisture fluctuations. Soil moisture deficits are ultimately tied to drought stress on plants. The diverse terrain and climate of Oklahoma, the extensive soil moisture network of the Oklahoma Mesonet, and satellite-derived indices from the Moderate Resolution Imaging Spectroradiometer (MODIS) provided an opportunity to study correlations between soil moisture and vegetation indices over the 2002-2006 growing seasons. Results showed that the correlation between both indices and the fractional water index (FWI) was highly dependent on land cover heterogeneity and soil type. Sites surrounded by relatively homogeneous vegetation cover with silt loam soils had the highest correlation between the FWI and both vegetation-related indices (r???0.73), while sites with heterogeneous vegetation cover and loam soils had the lowest correlation (r???0.22). Copyright 2008 by the American Geophysical Union.

  15. Índice de cobertura vegetal pela cultura do milho no período de chuvas intensas no sul de Minas Gerais Plant cover index in the period of intensive rainfall for corn crop at south of Minas Gerais state, Brazil

    Directory of Open Access Journals (Sweden)

    Fabiana Silva de Souza

    2010-04-01

    Full Text Available A cobertura vegetal é a defesa natural do solo contra a erosão hídrica. Nos modelos de estimativas de perdas de solo, o efeito da cobertura vegetal na interceptação da energia cinética da chuva é a variável chave na modelagem do processo erosivo. Assim sendo, objetivou-se avaliar a eficiência da cobertura vegetal, proporcionada pela cultura do milho, e suas relações com os atributos fitotécnicos desta cultura para alguns híbridos. O estudo foi realizado no campo demonstrativo de híbridos de milho da Universidade Federal de Lavras, localizada no município de Lavras, MG. Para determinação da cobertura vegetal utilizou-se um aparato que consiste em uma estrutura horizontal, contendo orifícios para visualização dos pontos com cobertura e sem cobertura vegetal, sendo as leituras feitas de forma aleatória e transversalmente às linhas da cultura. Os atributos fitotécnicos avaliados foram altura da planta, estande, matéria seca e produção de grãos. Diante dos resultados pode-se concluir que o maior índice de cobertura vegetal foi observado para os híbridos de milho P 30F33, P 30F90, P 3021, STRIKE, FORT, VALENT, UFLA 2001, UFLA 2004, CO 32, D 8480, D 8420 DKB 333B, DKB 440, evidenciando boa qualidade como planta protetora do solo. No período de maior ocorrência de chuvas, na região sul de Minas Gerais, a cultura do milho pode minimizar o efeito do processo erosivo. A produção de matéria seca relacionou-se bem com o índice de cobertura vegetal, podendo ser um indicativo quanto à proteção do solo.The plant cover is a natural protection of soil against water erosion. In estimative models of soil loss, the effect of plant cover in the interception of rainfall kinetic energy is the key variable in the modeling of the erosive process. Thus, the aim of this work is to evaluate the efficiency of the plant cover provided by the corn crop and their relations with the phytotechnical attributes of this crop for its respective

  16. Extraction of snow cover information in sparse vegetation area based on spectral measurement and SRF by using MODIS data%基于实测光谱和SRF的稀疏植被区MODIS积雪信息提取

    Institute of Scientific and Technical Information of China (English)

    刘艳; 李杨; 张璞

    2013-01-01

    以新疆准噶尔盆地古尔班通古特沙漠为研究区,以中等分辨率成像光谱仪(MODIS 1B)数据为例,辅以MODIS光谱响应函数(SRF)和全波段光谱仪(ASD)准同步采集的雪面反射光谱,运用线性光谱混合模型(LSMM)实现了稀疏植被区积雪遥感信息提取.结果表明:①利用SRF对雪面反射光谱进行端元光谱到像元光谱的转换,生成对应于MODIS1-7波段的离散光谱,将其与用最小噪声分离(MNF)变换和像元纯度指数(PPI)法获得的MODIS影像端元光谱进行对比,发现MODIS1波段光谱值远大于转换光谱值,MODIS2-7波段光谱值与转换光谱值接近;②MODIS2-7波段影像端元光谱值适用于LSMM估算稀疏植被区积雪分量,积雪分量估算值与归一化差分积雪指数(NDSI)拟合结果显示,剔除MODIS1波段后估算的积雪分量与NDSI的相关性显著提高,表明所提取的积雪分量可以作为估算积雪的典型指数.%In this paper, the linear spectral mixture model (LSMM) was used for the spectral unmixing analysis of the Moderate Resolution Imaging Spectrometer(MODIS)data of the study area in Gurbantunggut desert. Using the spectral response function (SRF) of MODIS1 -7 bands,the authors transformed the end -member spectrum quasi -synchronously collected by the full - band spectrometer ( ASD ) to the pixel spectra, thus generating the discrete spectrum of M0DIS1 - 7 bands. Compared with the MODIS end - member spectra obtained by minimum noise fraction ( MNF) transform and pixel purity index (PPI) ,the end - member spectral values of the first band of MODIS were much larger than the transformed spectrum values, but the spectral values of the MODIS2 - 7 bands were close to the transformed values. Therefore,selecting the image end - member spectral values of the MODIS2 -7 bands, the authors used LSMM to estimate the abundance of snow in the sparse vegetation area appropriately. Fitting the estimated snow component value to the normalized

  17. Natural Vegetation of the Flora area

    DEFF Research Database (Denmark)

    Sebsebe, Demissew; Friis, Ib

    2009-01-01

    A review article summarising the recent ideas about the natural vegetation in the area covered by the Flora of Ethiopia and Eritrea......A review article summarising the recent ideas about the natural vegetation in the area covered by the Flora of Ethiopia and Eritrea...

  18. Influence of lettuce as cover crop of the soil on sprinkler irrigation uniformity and parameters of efficiency Influência da cobertura vegetal com alface sobre os parâmetros de eficiência e uniformidade da aspersão

    Directory of Open Access Journals (Sweden)

    Patricia Angélica A Marques

    2009-09-01

    Full Text Available The effect of lettuce as cover crop was evaluated on sprinkler irrigation uniformity and parameters of efficiency. The experiment was carried out in field at the Universidade do Oeste Paulista, in Presidente Prudente, São Paulo, Brazil, from August to October, 2006. One treatment was performed on bare soil and the other using lettuce cultivar Vera as cover crop, at the end of the cycle. The average water depth, application rate, uniformity of distribution coefficient, Christiansen uniformity coefficient, Hawaiian uniformity coefficient, as well as the statistical uniformity coefficient were evaluated. The following plant spacing were simulated: 12 x 12, 12 x 18, and 18 x 18 m. The highest water depth retained with lettuce crop cover, at the end of the cycle was 2.4 mm, applied when sprinklers were spaced at 12 x 12 m. The same occurred in the application rate with an average reduction of 43%. When the overlapping was performed, the crop cover did not influence the parameters of efficiency and uniformity, assuring the distribution of the irrigation depth. Neither treatment reached the expected rate concerning the water depth average or the application rate in the spaces. The treatment using cover crop presented the lowest value, with a water depth average below the intended amount. Therefore, the lettuce as cover crop promotes the reduction of applied water depth. Consequently, the irrigation time has to be increased to assure the expected water depth.O efeito da cobertura vegetal promovido pela alface foi avaliado nos parâmetros de eficiência e uniformidade da irrigação por aspersão. O experimento foi instalado em campo da Universidade do Oeste Paulista, em Presidente Prudente-SP, de agosto a outubro de 2006, sendo um tratamento com solo nu, sem cobertura vegetal, e outro tratamento com solo com cobertura vegetal (alface cultivar Vera no final do ciclo. Foram avaliados a lâmina média aplicada, intensidade de aplicação, coeficiente de

  19. Capability of Spaceborne Hyperspectral EnMAP Mission for Mapping Fractional Cover for Soil Erosion Modeling

    Directory of Open Access Journals (Sweden)

    Sarah Malec

    2015-09-01

    Full Text Available Soil erosion can be linked to relative fractional cover of photosynthetic-active vegetation (PV, non-photosynthetic-active vegetation (NPV and bare soil (BS, which can be integrated into erosion models as the cover-management C-factor. This study investigates the capability of EnMAP imagery to map fractional cover in a region near San Jose, Costa Rica, characterized by spatially extensive coffee plantations and grazing in a mountainous terrain. Simulated EnMAP imagery is based on airborne hyperspectral HyMap data. Fractional cover estimates are derived in an automated fashion by extracting image endmembers to be used with a Multiple End-member Spectral Mixture Analysis approach. The C-factor is calculated based on the fractional cover estimates determined independently for EnMAP and HyMap. Results demonstrate that with EnMAP imagery it is possible to extract quality endmember classes with important spectral features related to PV, NPV and soil, and be able to estimate relative cover fractions. This spectral information is critical to separate BS and NPV which greatly can impact the C-factor derivation. From a regional perspective, we can use EnMAP to provide good fractional cover estimates that can be integrated into soil erosion modeling.

  20. 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...

  1. Protection against productivity versus erosion vineyards. Testing of vegetal covers in slope crops; Proteccion contra la erosion versus productividad en venidos. Ensayos de cubiertas vegetales en cultivos en pendiente

    Energy Technology Data Exchange (ETDEWEB)

    Marques, M. J.; Ruiz-Colmenero, M.; Garcia-Munoz, S.; Cabello, F.; Munoz-Organero, G.; Perez-Jimenez, M. A.; Bienes, R.

    2009-07-01

    Temporary and permanent cover crops were used in three rain fed vineyards in the Center of Spain. They were sown in the middle of the strips to assess their ability to control erosion as well as their influence on grape production. Data from the year 2008 are compared with those obtained with traditional tillage treatment. The permanent cover formed by Brachypodium distachyon showed better ability to control erosion but it produced a decrease in production in young vines. barley and rye treatments were temporary covers, mowed in spring. They also reduced the erosion compared with the tillage however they did not appear to affect the vineyard production. (Author)

  2. Ten Years of Land Cover Change on the California Coast Detected using Landsat Satellite Image Analysis

    Science.gov (United States)

    Potter, Christopher S.

    2013-01-01

    Landsat satellite imagery was analyzed to generate a detailed record of 10 years of vegetation disturbance and regrowth for Pacific coastal areas of Marin and San Francisco Counties. The Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) methodology, a transformation of Tasseled-Cap data space, was applied to detected changes in perennial coastal shrubland, woodland, and forest cover from 1999 to 2009. Results showed several principal points of interest, within which extensive contiguous areas of similar LEDAPS vegetation change (either disturbed or restored) were detected. Regrowth areas were delineated as burned forest areas in the Point Reyes National Seashore (PRNS) from the 1995 Vision Fire. LEDAPS-detected disturbance patterns on Inverness Ridge, PRNS in areas observed with dieback of tanoak and bay laurel trees was consistent with defoliation by sudden oak death (Phytophthora ramorum). LEDAPS regrowth pixels were detected over much of the predominantly grassland/herbaceous cover of the Olema Valley ranchland near PRNS. Extensive restoration of perennial vegetation cover on Crissy Field, Baker Beach and Lobos Creek dunes in San Francisco was identified. Based on these examples, the LEDAPS methodology will be capable of fulfilling much of the need for continual, low-cost monitoring of emerging changes to coastal ecosystems.

  3. Sganzerla Cover

    Directory of Open Access Journals (Sweden)

    Victor da Rosa

    2014-06-01

    Full Text Available http://dx.doi.org/10.5007/2175-7917.2014v19n1p158 Neste artigo, realizo uma leitura do cinema de Rogério Sganzerla, desde o clássico O bandido da luz vermelha até os documentários filmados na década de oitenta, a partir de duas noções centrais: cover e over. Para isso, parto de uma controvérsia com o ensaio de Ismail Xavier, Alegorias do subdesenvolvimento, em que o crítico realiza uma leitura do cinema brasileiro da década de sessenta através do conceito de alegoria; depois releio uma série de textos críticos do próprio Sganzerla, publicados em Edifício Sganzerla, procurando repensar as ideias de “herói vazio” ou “cinema impuro” e sugerindo assim uma nova relação do seu cinema com o tempo e a representação; então busco articular tais ideias com certos procedimentos de vanguarda, como a falsificação, a cópia, o clichê e a colagem; e finalmente procuro mostrar que, no cinema de Sganzerla, a partir principalmente de suas reflexões sobre Orson Welles, a voz é usada de maneira a deformar a interpretação naturalista.

  4. Cover Picture.

    Science.gov (United States)

    Breuning; Ruben; Lehn; Renz; Garcia; Ksenofontov; Gütlich; Wegelius; Rissanen

    2000-07-17

    The cover picture shows how both, fine arts and science, avail themselves of a system of intertwined symbolic and iconic languages. They make use of a common set of abstracted signs to report on their results. Thus, already in 1925, Wassily Kandinsky painted a masterpiece (bottom), which now, 75 years later, might be regarded as a blueprint for a scientific project. In his painting, Kandinsky pictured a grid-shaped sign