WorldWideScience

Sample records for degraded sandy grassland

  1. Nematode Faunal Response to Grassland Degradation in Horqin Sandy Land

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The responses of soil nematode communities to grassland degradation were studied under undegraded grassland (UG),degraded grassland (DG), and improved grassland (IG), in Horqin Sandy Land, Inner Mongolia, Northeast China. Soil samples were collected at depths of 0-10, 10-20, and 20-30 cm. Total organic carbon (TOC) and total nitrogen (TN)exhibited positive effects on the total number of nematodes and trophic groups. Significant treatment effects were found in the total number of nematodes, plant parasites, and omnivores-predators. Measures taken in the improved grassland could improve the number of omnivore-predators, especially in the deeper soil layers. Nematode richness was lower in the DG treatment than in the IG and UG treatments. The food web structure index (SI) was significantly higher in the UG and IG treatments than in the DG treatment. A higher SI suggested a food web with more trophic linkages and relatively healthy ecosystems.

  2. [Effects of degraded sandy grassland afforestation on soil quality in semi-arid area of northern China].

    Science.gov (United States)

    Hu, Ya-lin; Zeng, De-hui; Fan, Zhi-ping; Ai, Gui-yan

    2007-11-01

    By the methods of field survey and incubation test, this paper studied the effects of degraded sandy grassland afforestation with Mongolian pine on the soil physical, chemical and biological properties in 0-10 cm layer on Keerqin sandy land. The results showed that after 32 years afforestation, soil organic C, total N and total P decreased by 21%, 42% and 45%, respectively. In May and November, soil NH4+ -N content was significantly higher under Mongolian pine plantation than under grassland (P = 0.001; P = 0.019), but in May, August and November, soil NO3- -N content was in adverse (P soil C mineralization rate was higher under Mongolian pine plantation than under grassland, but the difference in N mineralization rate was not significant (P > 0.05). In May and August, soil microbial biomass C under Mongolian pine plantation and grassland had little difference, but in November, it was significantly higher under Mongolian pine plantation than under grassland. Soil nutrients- and moisture contents were the important factors affecting soil microbial biomass C. Soil urease and invertase activities decreased but catalase activity increased under Mongolian pine plantation, compared with those under grassland. It was suggested that 32 years afforestation of degraded sandy grassland with Mongolian pine on Keerqin sandy land led to a definite degradation of soil quality. Owing to the changes of vegetation, the test indicators of soil quality had different seasonal dynamic characteristics under Mongolian pine plantation and grassland. As a means of degraded ecosystem restoration in semi-arid area of Northern China, afforestation had its definite limitations.

  3. Vegetation pattern variation, soil degradation and their relationship along a grassland desertification gradient in Horqin Sandy Land, northern China

    Science.gov (United States)

    Zuo, Xiaoan; Zhao, Halin; Zhao, Xueyong; Guo, Yirui; Yun, Jianying; Wang, Shaokun; Miyasaka, Takafumi

    2009-09-01

    The Horqin Sandy Land is one of the most severely desertified regions in northern China. Plant communities and soil conditions at five stages of grassland desertification (potential, light, moderate, severe and very severe) were selected for the study of vegetation pattern variation relating to soil degradation. The results showed that vegetation cover, species richness and diversity, aboveground biomass (AGB), underground biomass, litter, soil organic carbon (C), total nitrogen (N), total phosphorus (P), electrical conductivity, very fine sand (0.1-0.05 mm) content and silt (0.05-0.002 mm) content decreased with the desertification development. Plant community succession presented that the palatable herbaceous plants gave place to the shrub species with asexual reproduction and sand pioneer plants. The decline of vegetation cover and AGB was positively related to the loss of soil organic C and total N with progressive desertification ( P < 0.01). The multivariate statistical analysis showed that plant community distribution, species diversity and ecological dominance had the close relationship with the gradient of soil nutrients in the processes of grassland desertification. These results suggest that grassland desertification results in the variation of vegetation pattern which presents the different composition and structure of plant community highly influenced by the soil properties.

  4. Soil Seed Bank and Plant Community Development in Passive Restoration of Degraded Sandy Grasslands

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    Renhui Miao

    2016-06-01

    Full Text Available To evaluate the efficacy of passive restoration on soil seed bank and vegetation recovery, we measured the species composition and density of the soil seed bank, as well as the species composition, density, coverage, and height of the extant vegetation in sites passively restored for 0, 4, 7, and 12 years (S0, S4, S7, and S12 in a degraded grassland in desert land. Compared with S0, three more species in the soil seed bank at depths of 0–30 cm and one more plant species in the community was detected in S12. Seed density within the topsoil (0–5 cm was five times higher in S12 than that in S0. Plant densities in S7 and S12 were triple and quadruple than that in S0. Plant coverage was increased by 1.5 times (S4, double (S7, and triple (S12 compared with S0. Sørensen’s index of similarity in species composition between the soil seed bank and the plant community were high (0.43–0.63, but it was lower in short-term restoration sites (S4 and S7 than that in no and long-term restoration sites (S0 and S12. The soil seed bank recovered more slowly than the plant community under passive restoration. Passive restoration is a useful method to recover the soil seed bank and vegetation in degraded grasslands.

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

    Science.gov (United States)

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

    2007-01-01

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

  6. Acidification of sandy grasslands - consequences for plant diversity

    DEFF Research Database (Denmark)

    Olsson, Pål Axel; Mårtensson, Linda-Maria; Bruun, Hans Henrik

    2009-01-01

    Questions: (1) Does soil acidification in calcareous sandy grasslands lead to loss of plant diversity? (2) What is the relationship between the soil content of lime and the plant availability of mineral nitrogen (N) and phosphorus (P) in sandy grasslands? Location: Sandy glaciofluvial deposits...... in south-eastern Sweden covered by xeric sand calcareous grasslands (EU habitat directive 6120). Methods: Soil and vegetation were investigated in most of the xeric sand calcareous grasslands in the Scania region (136 sample plots distributed over four or five major areas and about 25 different sites...

  7. Effects of grazing and climate change on species diversity in sandy grassland, Inner Mongolia, China

    Institute of Scientific and Technical Information of China (English)

    Toshiya; Okuro

    2009-01-01

    To understand the effects of animal grazing activities and climate change on sandy grassland vegetation in northern China, a field grazing and protected enclosure experiment was conducted from 1992 through 2006 in Horqin Sand Land, Inner Mongolia. The results showed that (1) the grazing was primary responsible for changes of the vegetation richness and diversity in the grazing grassland and that changing climate was the main reason for changes in the species richness and diversity in the grassland protected from grazing; (2) light and moderate grazing can promote restoration of the richness and the diversity in the degraded grassland, and heavy grazing could result in a decrease of the richness and diversity; (3) heavy grazing can result in significant decrease of the perennial diversity, and moderate and light grazing promotes increase of the perennial diversity; the grazing, whether heavy or moderate and light grazing, was beneficial to increase of the annual diversity; (4) heavy grazing was not beneficial to diversity of Graminean and Chenopodiaceae, and moderate and light grazing was favorable the diversity of Compositae and Chenopodiaceae; (5) the warm-humid climate was favorable to increase of the richness and the diversity, and the warm-drought climate could result in decease of the richness and the diversity; (6) increased precipitation was favorable to perennial diversity and the diversity of Graminean, Leguminosae, and Compositae, and decreased precipitation had few effects on the annual diversity and Chenopodiaceae diversity.

  8. Differentiating climate- and human-induced drivers of grassland degradation in the Liao River Basin, China.

    Science.gov (United States)

    He, Chunyang; Tian, Jie; Gao, Bin; Zhao, Yuanyuan

    2015-01-01

    Quantitatively distinguishing grassland degradation due to climatic variations from that due to human activities is of great significance to effectively governing degraded grassland and realizing sustainable utilization. The objective of this study was to differentiate these two types of drivers in the Liao River Basin during 1999-2009 using the residual trend (RESTREND) method and to evaluate the applicability of the method in semiarid and semihumid regions. The relationship between the normalized difference vegetation index (NDVI) and each climatic factor was first determined. Then, the primary driver of grassland degradation was identified by calculating the change trend of the normalized residuals between the observed and the predicted NDVI assuming that climate change was the only driver. We found that the RESTREND method can be used to quantitatively and effectively differentiate climate and human drivers of grassland degradation. We also found that the grassland degradation in the Liao River Basin was driven by both natural processes and human activities. The driving factors of grassland degradation varied greatly across the study area, which included regions having different precipitation and altitude. The degradation in the Horqin Sandy Land, with lower altitude, was driven mainly by human activities, whereas that in the Kungl Prairie, with higher altitude and lower precipitation, was caused primarily by climate change. Therefore, the drivers of degradation and local conditions should be considered in an appropriate strategy for grassland management to promote the sustainability of grasslands in the Liao River Basin.

  9. Sandy grassland blowouts in Hulunbuir,northeast China:geomorphology,distribution,and causes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Altan MunkhDalai; FENG Zongwei; WANG Xiaoke; SUN Hongwei; ZHAO Jiaming; U Hurlee

    2007-01-01

    A sandy grassland blowout consists of an aeolian depression formed in top soil and the underlying sand deposit underlie,and the adjoining redeposit of sand derived from the depression. Research based on field survey and topographic mapping combined with aerophotograph interpretation reveals that: (1) All the three sand land tracts in Hulunbuir Grasslands are composed of blowout depressions and adjoining dunes, with interlaying remnants of sandy grasslands as background; (2) blowout depressions and their adjoining dunes can be classified according to their morphometric characteristics, development stages, and initiating factors; (3) blowouts develop mostly in the upper parts of sidelong aweather and sunward slopes inclining southwestward when west wind prevails; (4) initiation of blowouts is closely related with the coupling of extreme droughts and wide spread intense human disturbance to the fragile topsoil layer. The investigations indicate that key factors to prevent desertification are to protect grassland vegetation and topsoil.

  10. Spatial patterns of wetting characteristics in grassland sandy soil

    Directory of Open Access Journals (Sweden)

    Orfánus Tomáš

    2016-06-01

    Full Text Available In grasslands where organic and inorganic resources are alternating at scales of individual plants, the transient character is given to certain wetting properties of soil, which then become highly variable both in space and in time. The objective of presented study was to study wetting pattern within two soil horizons at 5-cm and 10-cm depths respectively and to examine how the wetting patterns relate to hydraulic conductivity determined by Minidisc infiltrometer at suction −2 cm, K(−2 cm. This characteristics is implicitly independent on antecedent soil water content (SWC since it relates to steady infiltration phase but can be influenced by present soil water repellency (SWR. Field measurements were performed on July 27–28, 2010 on the grassland experimental site located near the village Sekule in Southwest Slovakia. The water drop penetration time (WDPT, SWC and tension Minidisc infiltration measurements were carried out on the 0.64 m2 plot in a regular 8 × 8 grid. The results showed that SWR and SWC influence each other and cause correlation between spatial patterns of studied soil wetting characteristics and between characteristics measured at the two soil depths. Further, it was found out, that calculation of K(−2 cm according to Zhang may cause apparent correlation of K(−2 cm with antecedent SWC, which is the artificial effect of sorptivity parameter in the equation on steady stage of infiltration process. This pseudocorrelation has disappeared after adopting of Minasny and McBratney (2000 approaches by calculation of K(−2 cm.

  11. Grassland Degradation and Its Control in Region Around Qinghai Lake

    Institute of Scientific and Technical Information of China (English)

    JIANGJIANJUN; GongAIQI; 等

    1999-01-01

    A quite severe degradation was found in all seven types of grasslands in the study area involiving 12 counties of the northwestern Qinghai Province.The slightly,modeately and severely degraded grasslands occupied 49.7%,32.0%and 18.3% of the area respectively.The major factors resulting in the degradation were overgrazing,the damages from mice and grasshopper and blown sands,and improper use of grasslands,The measures to deal with these probles should be:1) to make livestock development in accordance with grassland carrying capacity for animals;2) to build more artificial grasslands with a stable and higher grass yield;3) to put more widely the rotation grazing system into practice;4) to clear up the poisonous grass species,and 5)to adopt more effective measures to deal with the damages to grasslands by mice and grasshoppers.

  12. Field investigation of surface sand and dust movement over different sandy grasslands in the Otindag Sandy Land, China

    Science.gov (United States)

    Liu, Shulin; Wang, Tao; Chen, Guangting; Guo, Jian; Xue, Xian; Ma, Shaoxiu

    2008-01-01

    The characteristics of sand and dust movement over different sandy grasslands in China’s Otindag Sandy Land were explored based on field observations and laboratory analyses. Threshold wind speeds (the speed required to initiate sand movement) at a height of 2 m above the ground were estimated in the field for different surface types. Threshold wind speed above shifting dunes in the study area is about 4.6 m s-1 at this height. This value was smaller than values observed above other surfaces, resulting in a greater risk of blowing sand above these dunes. Differences in sand transport rates (STR) as a function of the severity of desertification resulted primarily from differences in surface vegetation cover and secondarily from the soil’s grain-size distribution. STR increased exponentially with increasing near-bed wind velocity. Under the same wind conditions, STR increased with increasing severity of desertification: from 0.08 g cm-2 min-1 above semi-fixed dunes to 8 g cm-2 min-1 above semi-shifting dunes and 25 g cm-2 min-1 above shifting dunes. Vegetation’s affect on STR was clearly large. Different components of sand and dust were trapped over different lands: mostly sand grains but little dust were trapped above shifting dunes, but much dust was collected over semi-shifting and semi-fixed dunes. Human disturbance is likely to produce dust even from fixed dunes as a result of trampling by animals and vehicle travel. In addition, spring rainfall decreased the risk of sand and dust movement by accelerating germination of plants and the formation of a soil crust.

  13. Plant functional diversity enhances associations of soil fungal diversity with vegetation and soil in the restoration of semiarid sandy grassland

    OpenAIRE

    Zuo, Xiaoan; Wang, Shaokun; Lv, Peng; Zhou, Xin; Zhao, Xueyong; Zhang, Tonghui; Zhang, Jing

    2015-01-01

    Abstract The trait‐based approach shows that plant functional diversity strongly affects ecosystem properties. However, few empirical studies show the relationship between soil fungal diversity and plant functional diversity in natural ecosystems. We investigated soil fungal diversity along a restoration gradient of sandy grassland (mobile dune, semifixed dune, fixed dune, and grassland) in Horqin Sand Land, northern China, using the denaturing gradient gel electrophoresis of 18S rRNA and gen...

  14. Predicting parameters of degradation succession processes of Tibetan Kobresia grasslands

    Science.gov (United States)

    Lin, L.; Li, Y. K.; Xu, X. L.; Zhang, F. W.; Du, Y. G.; Liu, S. L.; Guo, X. W.; Cao, G. M.

    2015-11-01

    In the past two decades, increasing human activity (i.e., overgrazing) in the Tibetan Plateau has strongly influenced plant succession processes, resulting in the degradation of alpine grasslands. Therefore, it is necessary to diagnose the degree of degradation to enable implementation of appropriate management for sustainable exploitation and protection of alpine grasslands. Here, we investigated environmental factors and plant functional group (PFG) quantity factors during the alpine grassland succession processes. Principal component analysis (PCA) was used to identify the parameters indicative of degradation. We divided the entire degradation process into six stages. PFG types shifted from rhizome bunchgrasses to rhizome plexus and dense-plexus grasses during the degradation process. Leguminosae and Gramineae plants were replaced by sedges during the advanced stages of degradation. The PFGs were classified into two reaction groups: the grazing-sensitive group, containing Kobresia humilis Mey, and Gramineae and Leguminosae plants, and the grazing-insensitive group, containing Kobresia pygmaea Clarke. The first group was correlated with live root biomass in the surface soil (0-10 cm), whereas the second group was strongly correlated with mattic epipedon thickness and K. pygmaea characteristics. The degree of degradation of alpine meadows may be delineated by development of mattic epipedon and PFG composition. Thus, meadows could be easily graded and their use adjusted based on our scaling system, which would help prevent irreversible degradation of important grasslands. Because relatively few environmental factors are investigated, this approach can save time and labor to formulate a conservation management plan for degraded alpine meadows.

  15. Plant functional diversity enhances associations of soil fungal diversity with vegetation and soil in the restoration of semiarid sandy grassland.

    Science.gov (United States)

    Zuo, Xiaoan; Wang, Shaokun; Lv, Peng; Zhou, Xin; Zhao, Xueyong; Zhang, Tonghui; Zhang, Jing

    2016-01-01

    The trait-based approach shows that plant functional diversity strongly affects ecosystem properties. However, few empirical studies show the relationship between soil fungal diversity and plant functional diversity in natural ecosystems. We investigated soil fungal diversity along a restoration gradient of sandy grassland (mobile dune, semifixed dune, fixed dune, and grassland) in Horqin Sand Land, northern China, using the denaturing gradient gel electrophoresis of 18S rRNA and gene sequencing. We also examined associations of soil fungal diversity with plant functional diversity reflected by the dominant species' traits in community (community-weighted mean, CWM) and the dispersion of functional trait values (FD is). We further used the structure equation model (SEM) to evaluate how plant richness, biomass, functional diversity, and soil properties affect soil fungal diversity in sandy grassland restoration. Soil fungal richness in mobile dune and semifixed dune was markedly lower than those of fixed dune and grassland (P functional diversity explained nearly 70% variances of soil fungal richness. Strong association of soil fungal richness with the dominant species in the community supported the mass ratio hypothesis. Our results clearly highlight the role of plant functional diversity in enhancing associations of soil fungal diversity with community structure and soil properties in sandy grassland ecosystems.

  16. Grassland Evolution Under Soil Degradation: Numerical Simulation and Test

    Institute of Scientific and Technical Information of China (English)

    QI Xiang-Zhen; LIN Zhen-Shan

    2005-01-01

    Both theoretical and field observations were examined to study the close relationship between soil degeneration and the evolution of grassland vegetation. A general n-species model of equal competition under different degrees of soil degradation was applied to field data in order to probe the dynamic processes and mechanisms of vegetation evolution due to the effects of the soil's ecological deterioration on grassland vegetation. Comparisons were made between the theoretical results and the practical surveys with satisfactory results.

  17. Responses of plant diversity and species composition to the cessation of fertilization in a sandy grassland

    Institute of Scientific and Technical Information of China (English)

    Sheng-nan Shi; Zhan-yuan Yu; Qiong Zhao

    2014-01-01

    Nitrogen was the main limiting nutrient of net primary pro-duction in the southeastern Keerqin Sandy Lands, Northeast China. Spe-cies richness declined and biomass increased after five consecutive years of nitrogen fertilization of these sandy grasslands (2004-2008). After fertilization had been stopped for three years (2009-2011), we surveyed vegetation on previously fertilized plots to quantify changes in commu-nity composition. Respect species richness showed an increasing trend over time since the cessation of fertilization. Respect vegetation height and coverage showed decreasing trends over time since the cessation of fertilization. Species composition changed after fertilization ceased, the dominant species shifting from Cannabis sativa, Phragmites communis and Chenopodium acuminatum in 2008 to Cannabis sativa, Phragmites communis and Artemisia scoparia in 2011. Dominance of dominant species declined from 66.2%in 2008 to 57.5%in 2011. The importance value of annual plants in the earlier nitrogen addition plots was higher than in control plots, but the differences were not significant in 2011. The importance value of perennial plants differed significantly between treatments from 2009 to 2011. The reversion rate not only differed be-tween community characteristics, but also between functional groups in the same community characteristic. Although the residual effect of nitro-gen addition on vegetation was still observed three years after fertiliza-tion ceased, the vegetation showed signs of recovery.

  18. Indirect drivers of plant diversity-productivity relationship in semiarid sandy grasslands

    Directory of Open Access Journals (Sweden)

    X. A. Zuo

    2012-04-01

    Full Text Available Although patterns between plant diversity and ecosystem productivity have been much studied, a consistent relationship has not yet emerged. Differing patterns between plant diversity and productivity have been observed in response to spatial variability of environmental factors and vegetation composition. In this study, we measured vegetation cover, plant diversity, productivity, soil properties and site characteristics along an environmental gradient (mobile dune, semi-fixed dune, fixed dune, dry meadow, wet meadow and flood plain grasslands of natural sandy grasslands in semiarid areas of northern China. We used multivariate analysis to examine the relationships between environmental factors, vegetation composition, plant diversity and productivity. We found a positive correlation between plant diversity and productivity. Vegetation composition aggregated by the ordination technique of non-metric multidimensional scaling had also a significantly positive correlation with plant diversity and productivity. Environmental gradients in relation to soil and topography affected the distribution patterns of vegetation composition, species diversity and productivity. However, environmental gradients were a better determinant of vegetation composition and productivity than of plant diversity. Structural equation modeling suggested that environmental factors determine vegetation composition, which in turn independently drives both plant diversity and productivity. Thus, the positive correlation between plant diversity and productivity is indirectly driven by vegetation composition, which is determined by environmental gradients in soil and topography.

  19. Testing Associations of Plant Functional Diversity with Carbon and Nitrogen Storage along a Restoration Gradient of Sandy Grassland.

    Science.gov (United States)

    Zuo, Xiaoan; Zhou, Xin; Lv, Peng; Zhao, Xueyong; Zhang, Jing; Wang, Shaokun; Yue, Xiyuan

    2016-01-01

    The trait-based approach shows that ecosystem function is strongly affected by plant functional diversity as reflected by the traits of the most abundant species (community-weighted mean, CWM) and functional dispersion (FDis). Effects of CWM and FDis individually support the biomass ratio hypothesis and the niche complementarity hypothesis. However, there is little empirical evidence on the relative roles of CWM traits and FDis in explaining the carbon (C) and nitrogen (N) storage in grassland ecosystems. We measured plant functional traits in the 34 most abundant species across 24 sites along a restoration gradient of sandy grassland (mobile dune, semi-fixed dune, fixed dune, and grassland) in Horqin Sand Land, northern China. Thereafter, we calculated the CWM traits, the functional divergence of each single trait (FDvar) and the trait dispersion of multiple traits (FDis). We also measured the C and N storage in plant, litter, root, and soil. Using a stepwise multiple regression analysis, we further assessed which of the functional diversity components best explained C and N storage in the sandy grassland restoration. We found consistent links between C or N storage and leaf traits related to plant resource use strategy. However, the CWM of plant height was retained as an important predictor of C and N storage in plant, litter, soil, and total ecosystem in the final multiple models. CWMs of specific leaf area and plant height best predicted soil C and N storage and total ecosystem N storage. FDis was one of good predictors of litter C and N storage as well as total ecosystem C storage. These results suggest that ecosystem C and N pools in the sandy grassland restoration are primarily associated with the traits of the most abundant species in communities, thereby supporting the biomass ratio hypothesis. The positive associations of FDis with C storage in litter and total ecosystem provide evidence to support the niche complementarity hypothesis. Both functional

  20. Testing associations of plant functional diversity with carbon and nitrogen storage along a restoration gradient of sandy grassland

    Directory of Open Access Journals (Sweden)

    Xiaoan eZuo

    2016-02-01

    Full Text Available The trait-based approach shows that ecosystem function is strongly affected by plant functional diversity as reflected by the traits of the most abundant species (community-weighted mean, CWM and functional dispersion (FDis. Effects of CWM and FDis individually support the biomass ratio hypothesis and the niche complementarity hypothesis. However, there is little empirical evidence on the relative roles of CWM traits and FDis in explaining the carbon (C and nitrogen (N storage in grassland ecosystems. We measured plant functional traits in the 34 most abundant species across 24 sites along a restoration gradient of sandy grassland (mobile dune, semi-fixed dune, fixed dune and grassland in Horqin Sand Land, northern China. Thereafter, we calculated the CWM traits, the functional divergence of each single trait (FDvar and the trait dispersion of multiple traits (FDis. We also measured the C and N storage in plant, litter, root and soil. Using a stepwise multiple regression analysis, we further assessed which of the functional diversity components best explained C and N storage in the sandy grassland restoration. We found consistent links between C or N storage and leaf traits related to plant resource use strategy. However, the CWM of plant height was retained as an important predictor of C and N storage in plant, litter, soil and total ecosystem in the final multiple models. CWMs of specific leaf area and plant height best predicted soil C and N storage and total ecosystem N storage. FDis was one of good predictors of litter C and N storage as well as total ecosystem C storage. These results suggest that ecosystem C and N pools in the sandy grassland restoration are primarily associated with the traits of the most abundant species in communities, thereby supporting the biomass ratio hypothesis. The positive associations of FDis with C storage in litter and total ecosystem provide evidence to support the niche complementarity hypothesis. Both

  1. Grazing Resource Management and Grassland Degradation in Northern China

    Institute of Scientific and Technical Information of China (English)

    LI Ying; HAO Ruimin

    2011-01-01

    1 Introduction Grassland degradation in China's northem steppe has been a major and increasingly serious problem affecting the productivity and sustainability of pastoral systems.The economic and property rights reforms in the early 1980s dramatically modified grazing management and resource institutions in the area.Livestock were privatized,but most of the pastures were jointly used by all herding households or small groups within villages.When a seemingly accelerating deterioration of grassland condition was observed through the 1980s and 1990s,numerous research and government reports suggested that the reform had created the classic problem of resource degradation from privately owned animals grazing on common land (Hardin 1968).At the same time,pastures allocated to and actually controlled by individual households also were subject to overexploitation caused by perceived institutional uncertainties (Longworth and Williamson 1993).

  2. Grassland Degradation Alters Soil Carbon Turnover through Depth

    Science.gov (United States)

    Creamer, C.; Prober, S. M.; Chappell, A.; Farrell, M.; Baldock, J.

    2015-12-01

    Ecosystem degradation is widespread and changes in aboveground plant communities alter belowground soil processes. In Australia, grassy eucalyptus woodlands dominated by kangaroo grasses (Themeda trianda) were widely cleared during European settlement for agriculture, with only fragments remaining of this now threatened ecosystem. As remnant grassland fragments are used for livestock grazing, Themeda transitions through states of degradation, starting with red grasses (Bothriochloa spp) and then proceeding to less productive, increasingly degraded states dominated by either annual exotic weeds or native wallaby grasses (Rytidosperma spp) and spear grasses (Austrastipa spp). The aim of our experiment was to determine how soil organic matter dynamics (including erosion, root biomass, C storage and turnover) have been altered by the transition from deeply-rooted Themeda grass systems to more shallowly-rooted annual exotic weeds and wallaby/spear grass states. We sampled soils in five depth-based increments (0-5, 5-15, 15-30, 30-60, 60-100 cm) across this ecosystem transition at five sites across New South Wales, Australia. Caseium-137 analysis indicated erosion rates were similar among all ecosystems and were consistent with levels for grasslands in the region. Compared to the remnant Themeda grass systems, the degraded states had lower root biomass, lower carbon stocks and C:N ratios in the coarse fraction (> 50 μm), lower fungal : bacterial ratios, higher available phosphate, higher alkyl : O-alkyl C ratios, and faster mineralization of synthetic root-exudate carbon. All these metrics indicate the surprising finding of more microbially processed OM and faster turnover of newly added C in the degraded sites. Compared to one another, the two degraded sites differed in both C and N turnover, with the exotic weeds having higher dissolved organic N, inorganic N, and coarse fraction N, higher fine fraction C stocks, and greater microbial biomass. These differences likely

  3. Degraded Ecosystem and its Rehabilitating Measures in Sandy Areas of North China

    Institute of Scientific and Technical Information of China (English)

    ZHANGFengchun; LUQi

    2004-01-01

    Ecosystem degradation occurs in parallel with desertification process in sandy areas of North China. The vast sandy areas in North China are characterized with flexible environments and fragile ecosystems as well as intensive human activities. Due to the annual precipitation gradient decreases from east to west in North China, the whole sandy region falls into 3 main climatic zones: add, semi-add and dry sub-humid zones.The ecosystems in each type of climatic zones are different in climatic conditions, human activities,cultural dimensions, vegetation covers, landscapes, and causes and processes of ecosystem degradation.Therefore, the most effective rehabilitation measures of degraded ecosystems in different types of the climatic zones are also different. For the arid sandy areas, vegetation rehabilitation of degraded ecosystems needs to be completely closed, assisting with artificial measures, such as plantation, irrigation or others. For semi-add sandy areas, the effective measures of vegetation rehabilitation of degraded ecosystems include increasing of proportion of forests and rangelands and limitation of reclamation; reducing the carrying capacity of livestock on unit area of rangelands and growth of fodder plants; and plantation on the lowlands betweens and dunes. For the dry sub-humid areas, the most effective measure is enclosure of degraded ecosystems combined with plantation, and in some cases, just stop uses by grazing or reclamation.

  4. Effect of Nitrogen Fertilizer on Photosynthetic Rate of Leymus chinensis in Grassland of Different Degrading Degrees

    Institute of Scientific and Technical Information of China (English)

    Mingming WANG; Yajing BAO; Zhenghai LI; Shaohuan YANG; Jingping JIAO; Yanyu GUO

    2012-01-01

    [Objective] This study aimed to investigate the effect of nitrogen fertilizer on photosynthetic rate of Leymus chinensis in the grasslands of different degrading degrees. [Method] With the L. chinensis in Inner Mongolia Baiyinxile Ranch as the research object, different rations of nitrogen fertilizer were applied to the grassland (0, 30, 50, 80 g/m^2). The effect of different gradients of nitrogen fertilizer on photo- synthetic rate of Leymus chinensis, and the effect on grasslands of different degrading degrees were analyzed. [Result] The photosynthetic rate of L. chinensis in- creased with the increase of nitrogen gradients; in the grassland communities with different degrading degrees, the responses of the photosynthetic rate of L. chinensis to nitrogen fertilizer were different, and the response in the grassland with severe degradation was the best. [Conclusion] Nitrogen fertilizer played an important role in enhancing the restoration degree of grassland.

  5. Conservation of sandy calcareous grassland: what can be learned from the land use history?

    Directory of Open Access Journals (Sweden)

    Anja Madelen Ödman

    Full Text Available Understanding the land use history has proven crucial for the conservation of biodiversity in the agricultural landscape. In southern Sweden, very small and fragmented areas of the disturbance-dependent habitat xeric sand calcareous grassland support a large number of threatened and rare plants and animals. In order to find out if historical land use could explain variation in present-day habitat quality, the land use on eight such sites was traced back to the 18th century and compared with key factors such as the amount of bare sand, lime content and P availability. There was no support for the common explanation of the decline in xeric sand calcareous grassland being caused by abandonment of agricultural fields during the last century. Instead, fertilization history was the main explanation for the difference in depletion depth of CaCO3 seen between the sites. The decline in xeric sand calcareous grassland since the 18th century is most probably the result of the drastic changes in land use during the 19th century, which put an end to the extensive sand drift. Since cultivation was shown to have played an important role in the historical land use of xeric sand calcareous grassland, grazing alone may not be the optimal management option for these grasslands. Instead more drastic measures are needed to restore the high calcium content and maintain proper disturbance levels.

  6. Is grazing exclusion effective in restoring vegetation in degraded alpine grasslands in Tibet, China?

    Science.gov (United States)

    Yan, Yan; Lu, Xuyang

    2015-01-01

    Overgrazing is considered one of the key disturbance factors that results in alpine grassland degradation in Tibet. Grazing exclusion by fencing has been widely used as an approach to restore degraded grasslands in Tibet since 2004. Is the grazing exclusion management strategy effective for the vegetation restoration of degraded alpine grasslands? Three alpine grassland types were selected in Tibet to investigate the effect of grazing exclusion on plant community structure and biomass. Our results showed that species biodiversity indicators, including the Pielou evenness index, the Shannon-Wiener diversity index, and the Simpson dominance index, did not significantly change under grazing exclusion conditions. In contrast, the total vegetation cover, the mean vegetation height of the community, and the aboveground biomass were significantly higher in the grazing exclusion grasslands than in the free grazed grasslands. These results indicated that grazing exclusion is an effective measure for maintaining community stability and improving aboveground vegetation growth in alpine grasslands. However, the statistical analysis showed that the growing season precipitation (GSP) plays a more important role than grazing exclusion in which influence on vegetation in alpine grasslands. In addition, because the results of the present study come from short term (6-8 years) grazing exclusion, it is still uncertain whether these improvements will be continuable if grazing exclusion is continuously implemented. Therefore, the assessments of the ecological effects of the grazing exclusion management strategy on degraded alpine grasslands in Tibet still need long term continued research.

  7. Is grazing exclusion effective in restoring vegetation in degraded alpine grasslands in Tibet, China?

    Directory of Open Access Journals (Sweden)

    Yan Yan

    2015-06-01

    Full Text Available Overgrazing is considered one of the key disturbance factors that results in alpine grassland degradation in Tibet. Grazing exclusion by fencing has been widely used as an approach to restore degraded grasslands in Tibet since 2004. Is the grazing exclusion management strategy effective for the vegetation restoration of degraded alpine grasslands? Three alpine grassland types were selected in Tibet to investigate the effect of grazing exclusion on plant community structure and biomass. Our results showed that species biodiversity indicators, including the Pielou evenness index, the Shannon–Wiener diversity index, and the Simpson dominance index, did not significantly change under grazing exclusion conditions. In contrast, the total vegetation cover, the mean vegetation height of the community, and the aboveground biomass were significantly higher in the grazing exclusion grasslands than in the free grazed grasslands. These results indicated that grazing exclusion is an effective measure for maintaining community stability and improving aboveground vegetation growth in alpine grasslands. However, the statistical analysis showed that the growing season precipitation (GSP plays a more important role than grazing exclusion in which influence on vegetation in alpine grasslands. In addition, because the results of the present study come from short term (6–8 years grazing exclusion, it is still uncertain whether these improvements will be continuable if grazing exclusion is continuously implemented. Therefore, the assessments of the ecological effects of the grazing exclusion management strategy on degraded alpine grasslands in Tibet still need long term continued research.

  8. Trends in soil organic matter contents in Dutch grasslands and maize fields on sandy soils

    NARCIS (Netherlands)

    Hanegraaf, M.C.; Hoffland, E.; Kuikman, P.J.; Brussaard, L.

    2009-01-01

    There is considerable concern in Europe that soil organic matter (SOM) contents are declining, which would threaten both agriculture and the environment. We performed a trend analysis of SOM contents in sandy soils, using historic data from routine agricultural soil analyses. Data were selected from

  9. Grassland Degradation, Construction and the Economic-technological Strategies of Sustainable Development of Grassland-agriculture

    Institute of Scientific and Technical Information of China (English)

    WANG Hua; YU Hua-ying; OKAMOTO Chinobu; WANG Yu-sheng

    2004-01-01

    Natural grassland in the West of Northeastern China is located in 40° 0′ - 43° 5′ N latitude and 117° 0′ -127° 5′ Elongitude. It lies in the Lisp River Valley, the Songhua River Valley and Nen River Valley. About 130 years ago, this region had rich natural grassland resources, was numerically 26.67 millions in hectare of grasslands.Since the last stage of Qing Dynasty, the grassland has been destroyed seriously in 3 times. Up to now, this region only preserved about 2 millions in hectare of the grasslands. In addition, 3.33 millions in hectare of the grasslands have changed from primary grassland to desertification, salinizatio-nalkalinization and degeneration grasslands in the form of patches of bare soil (their simple form of a name is "3 kinds of degeneration grasslands"). This paper indicaed that in any period both grasslands destruction and its restoration were relevant to economic changes and economic systems,particularly to market economy in that time. The following agricultural economic-technological strategies have been production bases of concentrated feed crops and coarse herbage crops.

  10. Soil and plant responses to degradation of alpine grassland in source region of the Yellow River

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Land degradation has been rapidly taking place in source region of the Yellow River in China. This study was conducted during 2008 in Maduo County to investigate soil and plant changes in relation to land degradation. Several results were derived from this work. First, the soil organic carbon (SOC) and total nitrogen (TN) decreased significantly on the extremely degraded land comparing with the natural grassland. Second, soil bulk density increased as land degradation worsened. Soil bulk density of the extremely degraded land was significantly greater than that of the grassland. Third, pH showed no obvious variation pattern. Finally, aboveground biomass decreased from grassland to the moderately degraded land. But aboveground biomass increased on the extremely degraded land and very extremely degraded land with most aboveground biomass inedible for livestock.

  11. Tracing grassland degradation on the Eastern Tibetan Plateau with multi-temporal remote sensing data

    Science.gov (United States)

    Fassnacht, Fabian E.; Li, Li; Fritz, Andreas

    2017-04-01

    The Tibetan Plateau in Western China is the world's largest alpine landscape, sheltering a rich diversity of native flora and fauna. In the past few decades, the Tibetan Plateau was found to suffer from grassland degradation processes. Grassland degradation is assumed to not only endanger biodiversity but also to increase the risk for natural hazards in other parts of the country which are ecologically and hydrologically connected to the area. Grassland degradation is furthermore, changing the albedo of the surfaces of the Plateau and may therefore even notably affect atmospheric and climatic processes. However, the mechanisms behind the degradation processes remain poorly understood due to scarce baseline data and insufficient scientific research as well as manifold potential influences on the degradation processes including pastoral management, climate, herbivor mammals and administrative decisions. This study tries to contribute to this research gap by tracing grassland degradation processes by time-series analysis of multi-spectral Landsat data. After identifying the degraded areas, it is examined whether the degradation patterns relate to topographic properties, climatic gradients or administrative borders. Results from a first study showed that most degradation occurred in high-altitude areas, while slope and aspect where not having a notable influence. Furthermore, a climatic gradient within the study area was found to correlate with the degradation patterns observed for large extents. Currently, the study is being expanded over a larger area and more detailed spatially-adaptive analysis concerning the degradation drivers are being developed. Corresponding results will be presented. We conclude that remotely sensed patterns of grassland degradation can contribute to an improved understanding of the degradation processed on the Tibetan Plateau by providing spatially and temporally explicit information on the degradation processes at an adequate scale.

  12. Soil disturbance alters plant community composition and decreases mycorrhizal carbon allocation in a sandy grassland.

    Science.gov (United States)

    Schnoor, Tim Krone; Mårtensson, Linda-Maria; Olsson, Pål Axel

    2011-11-01

    We have studied how disturbance by ploughing and rotavation affects the carbon (C) flow to arbuscular mycorrhizal (AM) fungi in a dry, semi-natural grassland. AM fungal biomass was estimated using the indicator neutral lipid fatty acid (NLFA) 16:1ω5, and saprotrophic fungal biomass using NLFA 18:2ω6,9. We labeled vegetation plots with (13)CO(2) and studied the C flow to the signature fatty acids as well as uptake and allocation in plants. We found that AM fungal biomass in roots and soil decreased with disturbance, while saprotrophic fungal biomass in soil was not influenced by disturbance. Rotavation decreased the (13)C enrichment in NLFA 16:1ω5 in soil, but (13)C enrichment in the AM fungal indicator NLFA 16:1ω5 in roots or soil was not influenced by any other disturbance. In roots, (13)C enrichment was consistently higher in NLFA 16:1ω5 than in crude root material. Grasses (mainly Festuca brevipila) decreased as a result of disturbance, while non-mycorrhizal annual forbs increased. This decreases the potential for mycorrhizal C sequestration and may have been the main reason for the reduced mycorrhizal C allocation found in disturbed plots. Disturbance decreased the soil ammonium content but did not change the pH, nitrate or phosphate availability. The overall effect of disturbance on C allocation was that more of the C in AM fungal mycelium was directed to the external phase. Furthermore, the functional identity of the plants seemed to play a minor role in the C cycle as no differences were seen between different groups, although annuals contained less AM fungi than the other groups.

  13. Airflow and sediment movement within an inland blowout in Hulun Buir sandy grassland, Inner Mongolia, China

    Science.gov (United States)

    Sun, Yu; Hasi, Eerdun; Liu, Meiping; Du, Huishi; Guan, Chao; Tao, Binbin

    2016-09-01

    We measured wind flows and sediment transport rates through a blowout in Hulun Buir grassland, Inner Mongolia. Topography and the angle of incidence between the approaching wind and the blowout long-axis significantly affected the air flow. Flow separated and decelerated at the western wall and accelerated towards the east, until maximum wind speed occurred at the top of the depositional lobe, and then decelerated on the lee side. When airflow emerged on the eastern wall, resultant directions were always NW. When winds approached from directions within 17.5° of the blowout axis, both the northwestern and southwestern walls developed turbulent flow, and significant topographic steering occurred. The deceleration zone expanded eastwards from 10.3 to 12.8 m from the western rim. When the wind direction was more oblique than 17.5°, turbulent flow at the southwestern wall disappeared. 'S-shaped' flow intensified, causing more pronounced steering at the bottom, but topographic steering elsewhere was reduced, and the boundary of the deceleration moved to 10 m from the western rim. Minor sediment deposition occurred on the western wall, while other parts were eroded; maximum sediment transport occurred at the top of the depositional lobe. The approaching wind speed affected the sediment transport rate more than the direction; and spatial variability in sediment transport reflected differences in compaction, vegetation coverage, slope, aspect, and upwind sediment availability, resulting in asymmetrical development. Overall, flow-form interactions governed the flow structures and controlled the evolution of the blowout via sediment transport.

  14. Quantifying the pedo-ecohydrological structure and function of degraded, grassland ecosystems

    Science.gov (United States)

    Brazier, Richard E.

    2015-04-01

    Grassland ecosystems cover significant areas of the terrestrial land mass, across a range of geoclimates, from arctic tundra, through temperate and semi-arid landscapes. In very few locations, such grasslands may be termed 'pristine' in that they remain undamaged by human activities and resilient to changing climates. In far more cases, grasslands are being degraded, often irreversibly so, with significant implications for a number of ecosystem services related to water resources, soil quality, nutrient cycles, and therefore both global food and water security. This paper draws upon empirical research that has been undertaken over the last decade to characterise a range of different grasslands in terms of soil properties, vegetation structure and geomorphology and to understand how these structures or patterns might interact or control how the grassland ecosystems function. Particular emphasis is placed upon quantifying fluxes of water, within and from grasslands, but also fluxes of sediment, via the processes of soil erosion and finally fluxes of the macronutrients Nitrogen, Phosphorus and Carbon from the landscape to surface waters. Data are presented from semi-arid grasslands, which are subject to severe encroachment by woody species, temperate upland grasslands that have been 'improved' via drainage to support grazing, temperate lowland grasslands, that are unimproved (Culm or Rhôs pastures) and finally intensively managed grasslands in temperate regions, that have been significantly modified via land management practices to improve productivity. It is hypothesised that, once degraded, the structure and function of these very diverse grassland ecosystems follows the same negative trajectory, resulting in depleted soil depths, nutrient storage capacities and therefore reduced plant growth and long-term carbon sequestration. Results demonstrate that similar, but highly complex and non-linear responses to perturbation of the ecosystem are observed, regardless of

  15. Degradation of the Pesticides Mecoprop and Atrazine in Unpolluted Sandy Aquifers

    DEFF Research Database (Denmark)

    Klint, Mikala; Arvin, Erik; Jensen, Bjørn K.

    1993-01-01

    The potential for biodegradation of the pesticides mecoprop ((+/-)-2-(4-chloro-2-methyl-phenoxy)propionic acid) and atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) in an aerobic aquifer was investigated in laboratory batch experiments. The experiments were performed with groundwater...... and suspensions of groundwater and aquifer sediment collected from a pristine sandy aquifer. Following a lag period of 35 to 40 d, mecoprop in a concentration of 100 mu-g/L was degraded in 30 d in groundwater at 10 degree C. New additions of 100 to 140 mu-g mecoprop/L were degraded within a week. In suspensions...... of groundwater and aquifer sediment, mecoprop in the concentration range 75 to 300 mu-g/L was degraded in 15 d, following a lag period of less than 7 d. Experiments performed with sediments taken from different depths indicate that there was a considerable variation in the degradation potential within...

  16. Degradation increase responses of priming effects to temperature in Tibetan alpine grasslands

    Science.gov (United States)

    Sun, Yue; Li, Qianru; Schleuss, Per; Hua, Ouyang; Kuzyakov, Yakov

    2016-04-01

    Kobresia grassland in Tibet plateau, with a rich storage of soil organic carbon (SOC), is very important to both ecosystem function and the livelihoods of local pastoral communities. But its intensive degradation in recent decades has led to unclear consequences for SOC stocks and dynamics. Kobresia grassland acts as a critical "first response region" to climate change, where the SOC decomposition is highly sensitive to temperature, and can produce positive C climate feedback. Priming effects, induced by inputs of labile organic carbon (LOC), can also affect SOC dynamic. Therefore, knowledge about how the priming effects response to temperature, and how their interactions affect SOC decomposition are central to understanding the carbon cycle of Tibet plateau under global warming. To this ends, we conducted a laboratory incubation experiment with the non-degraded soil collected from intact Kobresia patches, and degraded soil collected from crust patches, labeled with 14C-glucose in high/low level and incubated under 0 °C, 10 °C and 20 °C for 80 days. Cumulated CO2 emission increased significantly with temperature. Degraded soil showed lower CO2 emission at 0 °C, but significant higher CO2 emission at higher temperature compared to that of non-degraded soil. Priming positively responded to increasing temperature, with 78.9% increment in degraded soil and 12.9% in non-degraded soil on average, and at 20 °C, it was significant higher in degraded soil than non-degraded soil. Low-level glucose input led to the positive priming effects, while high-level glucose induced the negative priming. Higher temperature led to higher microbial activity (i.e., qCO2) and enzyme activity (i.e., β-glucosidases, chitinase, cellobiohydrolase and Xylosidase). Vmax of enzyme was significantly higher in degraded soil than in non-degraded soil, exhibiting a positive linear regression with priming effects. In conclusion, increase in temperature improved priming effects via higher microbe

  17. Effects of land-use changes on organic carbon in bulk soil and associated physical fractions in China's Horqin Sandy Grassland

    Institute of Scientific and Technical Information of China (English)

    YuQiang Li; YinPing Chen; ShaoKun Wang; WenDa Huang; JianPeng Zhang

    2015-01-01

    The Horqin Sandy Grassland is one of the most seriously desertified areas in China's agro-pastoral ecotone due to its fragile ecology, combined with improper and unsustainable land management. We investigated organic carbon changes in bulk soil (0 to 5 cm), light fraction of soil organic matter, and soil particle-size fractions induced by land-use and cover type changes. The results indicated that total soil organic carbon (SOC) storage decreased by 121 g/m2 with the conversion of grassland into farmland for 30 years, and increased by 261 g/m2 with the conversion of grassland into plantation for 30 years. Total SOC storage decreased by 157 g/m2 as a result of severe grassland desertification due to long-term continuous livestock grazing, whereas total SOC increased by 111 g/m2 following the practice of grazing exclusion (16 years) in desertified areas. Changes in land-use and cover type also show great effects on carbon storage in soil physical fractions.

  18. A laboratory experiment of intact polar lipid degradation in sandy sediments

    Directory of Open Access Journals (Sweden)

    J. Logemann

    2011-03-01

    Full Text Available Intact polar lipids (IPLs are considered biomarkers for living biomass. Their degradation in marine sediments, however, is poorly understood and complicates interpretation of their occurrence in geological samples. To investigate the turnover of IPLs, a degradation experiment with anoxic sandy sediments from the North Sea was conducted. Intact cells of two organisms that do not naturally occur in North Sea sediments were chosen as IPL sources: (i Saccharomyces cerevisiae, representative for ester-bound acyl lipids that also occur in Bacteria, and (ii the archaeon Haloferax volcanii, representative for ether-bound isoprenoid lipids. Surprisingly, IPLs with phosphoester-bound head groups showed approximately the same degradation rate as IPLs with glycosidic head groups. Furthermore, the results indicate a relatively fast degradation of S. cerevisiae IPLs with ester-bound moieties (analogs of bacterial membrane lipids and no significant degradation of archaeal IPLs with ether-bound moieties. Pore water and 16S rRNA-based DGGE analysis showed only a minor influence of the IPL source on microbial metabolism and community profiles. Due to our results, the IPL-based quantification of Archaea and Bacteria should be interpreted with caution.

  19. A laboratory experiment of intact polar lipid degradation in sandy sediments

    Directory of Open Access Journals (Sweden)

    J. Logemann

    2011-09-01

    Full Text Available Intact polar lipids (IPLs are considered biomarkers for living biomass. Their degradation in marine sediments, however, is poorly understood and complicates interpretation of their occurrence in geological samples. To investigate the turnover of IPLs, a degradation experiment with anoxic sandy sediments from the North Sea was conducted. Intact cells of two organisms that do not naturally occur in North Sea sediments were chosen as IPL sources: (i Saccharomyces cerevisiae, representative for ester-bound acyl lipids that also occur in Bacteria, and (ii the archaeon Haloferax volcanii, representative for ether-bound isoprenoid lipids. Surprisingly, IPLs with phosphoester-bound head groups showed approximately the same degradation rate as IPLs with glycosidic head groups. Furthermore, the results indicate a relatively fast degradation of S. cerevisiae IPLs with ester-bound moieties (analogs of bacterial membrane lipids and no significant degradation of archaeal IPLs with ether-bound moieties. Pore water and 16S rRNA-based DGGE analysis showed only a minor influence of the IPL source on microbial metabolism and community profiles. Due to our results, the IPL-based quantification of Archaea and Bacteria should be interpreted with caution.

  20. Numerical Simulation of the Effects of Grassland Degradation on the Surface Climate in Overgrazing Area of Northwest China

    Directory of Open Access Journals (Sweden)

    Yanfei Li

    2013-01-01

    Full Text Available The climatic effects of LUCC have been a focus of current researches on global climate change. The objective of this study is to investigate climatic effects of grassland degradation in Northwest China. Based on the stimulation of the conversion from grassland to other land use types during the next 30 years, the potential effects of grassland degradation on regional climate in the overgrazing area of Northwest China from 2010 to 2040 have been explored with Weather Research and Forecasting model (WRF. The analysis results show that grassland will mainly convert into barren land, croplands, and urban land, which accounts for 42%, 48%, and 10% of the total converted grassland area, respectively. The simulation results indicate that the WRF model is appropriate for the simulation of the impact of grassland degradation on climate change. The grassland degradation during the next 30 years will result in the decrease of latent heat flux, which will further lead to the increase of temperature in summer, with an increment of 0.4–1.2°C, and the decrease of temperature in winter, with a decrement of 0.2°C. In addition, grassland degradation will cause the decrease of precipitation in both summer and winter, with a decrement of 4–20 mm.

  1. 科尔沁沙质草地封育过程中的植被变化及其机制%Change and Mechanism of Vegetation in the Fenced Sandy Grassland in Horqin Sandy Land

    Institute of Scientific and Technical Information of China (English)

    苗仁辉; 蒋德明; 王永翠

    2013-01-01

    对科尔沁沙地乌兰敖都地区的沙质草地封育后的植被变化及其机制进行分析研究.结果表明:①围栏封育使植被物种丰富度、密度显著提高,群落的优势种发生明显变化;围封地的Simpson多样性指数和Shannon-Wiener多样性指数均表现为随封育时间增加而下降,而Pielou均匀度指数随围封时间增加表现出先增加后下降的趋势.②围栏封育可以增加土壤表层(0~10 cm)的养分含量,但电导率随围封时间表现出先降低后增加的趋势,同时围栏封育使土壤水分含量下降.③土壤表层(0 ~ 10 cm)各因子对多样性的影响不同,全氮和pH与Pielou指数呈显著(P<0.05)负相关;全氮对于丰富度指数呈显著(P<0.05)正相关;其他土壤环境因子与多样性指数间关系均不显著,表明在沙质草地封育不利于植物多样性的维持,但有利于土壤养分的积累.%In this paper, the change and mechanism of vegetation in sandy grassland in Horqin Sandy Land during the natural regeneration process was studied. The study was carried out at Ulanaodu in Horqin Sandy Land. The results are as follows: (1) Vegetation density and species richness in the fenced grassland were obviously improved, and the dominant species of plant community were changed obviously. The indexes of Simpson and Shannon-Wiener species diversity were decreased with the increase of fenced time, whereas the Pielou evenness was increased at firstly, and then decreased with the increase of fenced period; (2) Nutrient content in topsoil (0-10 cm) in the fenced grassland was increased,but the electric conductivity was decreased at firstly,and then increased with the vegetation regeneration process. Soil moisture content was decreased with fenced time; (3) Effects of topsoil factors on the plant species diversity were different. There was a significant negative correlation (P <0. 05) between total N and the pH value and Pielou diversity index,but a positive

  2. Imazaquin degradation and metabolism in a sandy loam soil amended with farm litters

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Imazaquin applied in legume crops has a long residual time in soil,which often impacts safety of the susceptible crops.To increase safety of imazaquin application,two composted litters,bovine manure (BM) and chicken manure (CM),were used to determine their effects on imazaquin environmental behavior by incorporating each kind of manure into the tested sandy loam soil at 10% (w/w).The degradation of imazaquin in BM- and CM-amended soil was about 2.4 and 1.5 times,respectively,faster than that in unamended soil.The half-lives of imazaquin in BM-amended soil varied between 6.7 and 15.4 d over the temperature range of 20 to 40℃,and the degradation rate constant (k) increased by a factor of about 1.5 for every 10℃ change.Higher mix ratio did not significantly increase the degradation,and the optimal active degradation of imazaquin was observed approximately at the mix ratio of 10:1 of soil to BM.The different moisture levels had negligible effect on imazaquin degradation.In both unamended and BM-amended treatments.two metabolites were observed at 5,10 and 30 d after treatment.One metabolite at retention time (RT) of 8.4 min was identified as 2-(4-hydroxyl-5-oxo-2-imidazolin-2-y1) quinoline acid,originating from the loss of isopropyl group and hydroxylation at the 4-position of imidazolinone ring.The other at RT of 12.9 min was identified as quinolinc-2,3-dicarboxylic anhydride,resulting from detachment of imidazolinone ring and the forming of dicarboxylic anhydride.This finding suggested that the addition of farm litters into soil might be a good management option since it can not only increase soil fertility but also contribute to increase safety of imazaquin application to the following susceptible crops.

  3. Formation causes and recovery of the "Black Soil Type" degraded alpine grassland in Qinghai-Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    SHANG Zhanhuan; LONG Ruijun

    2007-01-01

    The formation causes and ecological rebuilding of the "Black Soil Type" degraded alpine grassland are summarized.The formation of the "Black Soil Type" degraded grassland was caused mainly by climate warming,decreasing glaciers,overgrazing,and damage by rats.The ecological restoration of the "Black Soil Type" degraded alpine grassland relies not only on grassland building,but also on reasonable management and planning of grassland resources.Guaranty measures for developing the alpine grassland animal husbandry in a healthy way include intensifying the educational investment in pasture regions,practicing long-term contracts for grassland,and strengthening the grassland legislation.The authors believe that the Qinghai-Tibetan Plateau ecosystem has a special characteristic inertia or "inert gases",which weaken the self-renewing capability of the ecosystem and makes its structure frail.The inertia characteristic may be the important reason that makes ecological rebuilding so difficult;in addition,other problems need to be studied deeply to provide scientific bases for the ecological building in the Qinghai-Tibetan Plateau.

  4. Feasibility Study on: Reforestation of Degraded Grasslands in Indonesia as a Climate Change Mitigation Option

    Energy Technology Data Exchange (ETDEWEB)

    Dalfelt, A.; Naess, L.O.; Sutamihardja, R.T.M.; Gintings, N.

    1996-12-31

    The report deals with a cooperation project between Norway and Indonesia dealing with a feasibility study on sustainable reforestation of degraded grasslands in Indonesia. Poor forest management and uncontrolled land use changes contribute a significant share anthropogenic emissions of greenhouse gases, especially CO{sub 2}, and one of many ways to reduce the CO{sub 2} emission is to encourage reforestation and better forest management. The report contains a brief overview of the issue of Imperata (alang-alang) grasslands, an outline of the present status, a discussion of potential costs and benefits associated with reforestation, and suggestions of strategies which could be applied to reach the desired goals. Case studies are presented from three locations where field work has been undertaken. The case studies provide baseline data about the sites and the imperata grasslands, experiences from earlier efforts to rehabilitate the grasslands, the common attitude to reforestation among the local communities, a discussion of the feasibility of reforestation, and finally, recommendations for the future. 142 refs., 11 figs., 15 tabs.

  5. Evaluating Anthropogenic Risk of Grassland and Forest Habitat Degradation using Land-Cover Data

    Directory of Open Access Journals (Sweden)

    Kurt Riitters

    2009-09-01

    Full Text Available The effects of landscape context on habitat quality are receiving increased attention in conservation biology. The objective of this research is to demonstrate a landscape-level approach to mapping and evaluating the anthropogenic risks of grassland and forest habitat degradation by examining habitat context as defined by intensive anthropogenic land uses at multiple spatial scales. A landscape mosaic model classifies a given location according to the amounts of intensive agriculture and intensive development in its surrounding landscape, providing measures of anthropogenic risks attributable to habitat isolation and edge effects at that location. The model is implemented using a land-cover map (0.09 ha/pixel of the conterminous United States and six landscape sizes (4.4, 15.2, 65.6, 591, 5300, and 47800 ha to evaluate the spatial scales of anthropogenic risk. Statistics for grassland and forest habitat are extracted by geographic overlays of the maps of land-cover and landscape mosaics. Depending on landscape size, 81 to 94 percent of all grassland and forest habitat occurs in landscapes that are dominated by natural land-cover including habitat itself. Within those natural-dominated landscapes, 50 percent of grassland and 59 percent of forest is within 590 m of intensive agriculture and/or intensive developed land which is typically a minor component of total landscape area. The conclusion is that anthropogenic risk attributable to habitat patch isolation affects a small proportion of the total grassland or forest habitat area, while the majority of habitat area is exposed to edge effects.

  6. RS-and-GIS-Supported Forecast of Grassland Degradation in Southwest Songnen Plain by Markov Model

    Institute of Scientific and Technical Information of China (English)

    LI Jianping; ZHANG Bai; GAO Feng

    2005-01-01

    By taking Daan city in Jilin Province as a research object and by using TM image in 1989 and ETM+ image in 2001 from American LANDSAT satellite,all kinds of maps and documentation,information of grassland,saline-alkalized land,cropland,water area and forestland is extracted by man-computer interactive interpretation method with ArcView and ArcInfo GIS software, and statistics data is acquired.On the basis of this the changing trend of land use types in the next ten years is forecasted and analyzed with Markov model.The results indicate that the problem of grassland degradation in the study area is quite serious.

  7. Mechanisms of soil degradation and consequences for carbon stocks on Tibetan grasslands

    Science.gov (United States)

    Kuzyakov, Yakov; Schleuss, Per-Marten; Miehe, Georg; Heitkamp, Felix; Sebeer, Elke; Spielvogel, Sandra; Xu, Xingliang; Guggenberger, Georg

    2016-04-01

    Tibetan grasslands provide tremendous sinks for carbon (C) and represent important grazing ground. Strong degradation - the destroying the upper root-mat/soil horizon of Kobresia pastures, has dramatic consequences for soil organic carbon (SOC) and nutrient storage. To demonstrate specific degradation patterns and elucidate mechanisms, as well as to assess consequences for SOC storage, we investigated a sequence of six degradation stages common over the whole Kobresia ecosystem. The soil degradation sequence consists of following mechanisms: Overgrazing and trampling by livestock provide the prerequisite for grassland degradation as both (a) cause plant dying, (b) reduce grassland recovery and (c) destroy protective Kobresia root-mats. These anthropogenic induced processes are amplified by naturally occurring degradation in harsh climate. The frequently repeated soil moisture and temperature fluctuations induce volume changes and tensions leading to polygonal cracking of the root mats. Then the plants die and erosion gradually extend the surface cracks. Soil erosion cause a high SOC loss from the upper horizons (0-10 cm: ~5.1 kg C m-2), whereas SOC loss beneath the surface cracks is caused by both, decreasing root C-input and SOC mineralization (SOC losses by mineralization: ~2.5 kg C m-2). Root biomass decreases with degradation and indicated lower C input. The negative δ13C shift of SOC reflects intensive decomposition and corresponds to a relative enrichment of 13C depleted lignin components. We conclude that the combined effects of overgrazing and harsh climate reduce root C input, increase SOC decomposition and initiate erosion leading to SOC loss up to 70% of intact soil (0-30 cm: ~7.6 kg C m-2). Consequently, a high amount of C is released back to the atmosphere as CO2, or is deposited in depressions and river beds creating a potential source of N2O and CH4. Concluding, anthropogenically induced overgrazing makes the Kobresia root-mat sensitive to natural

  8. The effects of fencing on carbon stocks in the degraded alpine grasslands of the Qinghai-Tibetan Plateau.

    Science.gov (United States)

    Li, Yuanyuan; Dong, Shikui; Wen, Lu; Wang, Xuexia; Wu, Yu

    2013-10-15

    Quantifying the carbon storage of grasslands under different management strategies can help us understand how this ecosystem responds to different land management practices. To assess the C cycle and the importance of soil microbial biomass carbon, we measured the levels of soil organic carbon, biomass carbon (above- and underground) and soil microbial biomass carbon in areas with different grazing intensities and different management strategy (fenced and unfenced) in the Qinghai-Tibetan Plateau. We also calculated the ratio of soil microbial biomass carbon to soil organic carbon as an indicator of the soil organic matter availability and quality. Results showed that degradation had significant effects on the soil organic carbon, biomass carbon and microbial biomass carbon (P fencing only had a significant effect on the non-degraded and moderately degraded grasslands (P fencing may be an important management strategy for restoring lightly or moderately degraded grassland in the Qinghai-Tibetan Plateau.

  9. The effects of grassland degradation on plant diversity, primary productivity, and soil fertility in the alpine region of Asia's headwaters.

    Science.gov (United States)

    Wang, Xuexia; Dong, Shikui; Yang, Bing; Li, Yuanyuan; Su, Xukun

    2014-10-01

    A 3-year survey was conducted to explore the relationships among plant composition, productivity, and soil fertility characterizing four different degradation stages of an alpine meadow in the source region of the Yangtze and Yellow Rivers, China. Results showed that plant species diversity, productivity, and soil fertility of the top 30-cm soil layer significantly declined with degradation stages of alpine meadow over the study period. The productivity of forbs significantly increased with degradation stages, and the soil potassium stock was not affected by grassland degradation. The vegetation composition gradually shifted from perennial graminoids (grasses and sedges) to annual forbs along the degradation gradient. The abrupt change of response in plant diversity, plant productivity, and soil nutrients was demonstrated after heavy grassland degradation. Moreover, degradation can indicate plant species diversity and productivity through changing soil fertility. However, the clear relationships are difficult to establish. In conclusion, degradation influenced ecosystem function and services, such as plant species diversity, productivity, and soil carbon and nitrogen stocks. Additionally, both plant species diversity and soil nutrients were important predictors in different degradation stages of alpine meadows. To this end, heavy degradation grade was shown to cause shift of plant community in alpine meadow, which provided an important basis for sustaining ecosystem function, manipulating the vegetation composition of the area and restoring the degraded alpine grassland.

  10. 草地退化的因素和退化草地的恢复及其改良%The Feature Analysis for Grassland Degradation and the Restoration of Natural Vegetation in Degraded Grassland

    Institute of Scientific and Technical Information of China (English)

    张文海; 杨韫

    2011-01-01

    Along with the increasing population pressure and need of new agriculture land, natural grasslands are being decimated. Grassland degradation has escalated into a world - wide problem. Because of using in the improper way, the degradation occurs in most of the natural grassland. And the process of grassland degradation is complex, Including geography, climate, soil, disasters and other natural factors. So we suggest that it is imperative for the Restoration of degraded grassland.%草地退化是一个世界性的普遍问题。几乎所有的天然草原和人工草地,在利用不当时都可能出现这种现象。对草地退化的过程和原因比较复杂。草地生态系统的变化过程总是伴随着相关的地理、气候、土壤、灾害等各种自然因素的作用,有时一二种自然因素(如火或洪水)就可能造成生态系统的退化。所以对退化草地的恢复势在必行,本文着重对近几年较流行的退化草地的恢复方法进行了介绍。

  11. Degradation of Tibetan grasslands: Consequences for soil organic carbon and nutrients losses

    Science.gov (United States)

    Liu, Shibin; Schleuss, Per-Marten; Kuzyakov, Yakov

    2017-04-01

    estimations regarding SOC and nutrients losses across the whole ecosystem. This highly matters because large amounts of SOC have been lost due to erosion and mineralization. Most likely this has polluted the Tibetan headwaters and contributed to climate change, respectively. Further, the decreasing N and P losses have reduced soil fertility lowering forage production. Therefore, it endangers the livelihood of the Tibetan herders, which highly rely on forage to feed their livestock. Despite plenty of ameliorations (e.g. fertilization, grazing enclosure, reseeding) have been proposed and implemented at many locations, their impacts on pasture ecosystems (especially on soil fertility) are still subtle and thus require further investigations. Keywords: Kobresia pastures, Tibetan Plateau, Grassland degradation, Soil organic carbon, Soil nutrients

  12. Strategies to alleviate poverty and grassland degradation in Inner Mongolia: intensification vs production efficiency of livestock systems.

    Science.gov (United States)

    Briske, David D; Zhao, Mengli; Han, Guodong; Xiu, Changbai; Kemp, David R; Willms, Walter; Havstad, Kris; Kang, Le; Wang, Zhongwu; Wu, Jianguo; Han, Xingguo; Bai, Yongfei

    2015-04-01

    Semi-nomadic pastoralism was replaced by sedentary pastoralism in Inner Mongolia during the 1960's in response to changes in land use policy and increasing human population. Large increases in numbers of livestock and pastoralist households (11- and 9-fold, respectively) during the past 60 yrs have variously degraded the majority of grasslands in Inner Mongolia (78 M ha) and jeopardize the livelihoods of 24 M human inhabitants. A prevailing strategy for alleviating poverty and grassland degradation emphasizes intensification of livestock production systems to maintain both pastoral livelihoods and large livestock numbers. We consider this strategy unsustainable because maximization of livestock revenue incurs high supplemental feed costs, marginalizes net household income, and promotes larger flock sizes to create a positive feedback loop driving grassland degradation. We offer an alternative strategy that increases both livestock production efficiency and net pastoral income by marketing high quality animal products to an increasing affluent Chinese economy while simultaneously reducing livestock impacts on grasslands. We further caution that this strategy be designed and assessed within a social-ecological framework capable of coordinating market expansion for livestock products, sustainable livestock carrying capacities, modified pastoral perceptions of success, and incentives for ecosystem services to interrupt the positive feedback loop that exists between subsistence pastoralism and grassland degradation in Inner Mongolia.

  13. Feedbacks between aeolian processes and ecosystem change in a degraded desert grassland in the southwestern US

    Science.gov (United States)

    Li, Junran

    2015-04-01

    The desert grassland in the southwestern US has undergone dramatic vegetation changes with many areas of grassland becoming shrublands in the last 150 years. A principle manifestation of such a land degradation is the wide distribution of fertile islands in once-homogenous landscapes, which changed soil resource redistributions through the movement of resources from plant interspaces to the area beneath plant canopies. A great deal of work has examined the role of water in nutrient reduction and enforcement of islands of fertility in the semiarid landscapes. However, little is known on the role of wind in the removal or redistribution of soil resources, and further the feedbacks between wind and ecosystem change in this area. In spring 2004, a vegetation removal experiment was established in the northern Chihuahuan Desert, southern New Mexico, where vegetation cover on the experimental plots were manually reduced to various levels to study the entire suite of aeolian processes, including erosion, transport, and deposition in creating and enforcing patchy distribution of vegetation. This experiment has been continually maintained for more than ten years, with the sampling and observation of vegetation cover, soil nutrients, sediment flux, topography, and plant physiology. The experimental results highlighted that the aeolian processes in the Chihuahuan Desert are able to change soil properties and community composition in as short as 3 three years. Further, the removal of grasses by 75% may trigger a very substantial increase of wind erosion and the removal of grass by 50% could cause significant amount of C and N loss due to wind erosion. Last but not least, the change of the spatial distribution of soil C and the micro-topography both point to the fact that aeolian processes contribute substantially to the dynamics of fertile islands in this desert grassland.

  14. Variation of soil hydraulic properties with alpine grassland degradation in the eastern Tibetan Plateau

    Science.gov (United States)

    Pan, Tao; Hou, Shuai; Wu, Shaohong; Liu, Yujie; Liu, Yanhua; Zou, Xintong; Herzberger, Anna; Liu, Jianguo

    2017-05-01

    Ecosystems in alpine mountainous regions are vulnerable and easily disturbed by global environmental change. Alpine swamp meadow, a unique grassland type in the eastern Tibetan Plateau that provides important ecosystem services to the upstream and downstream regions of international rivers of Asia and other parts of the world, is undergoing severe degradation, which can dramatically alter soil hydraulic properties and water cycling processes. However, the effects of alpine swamp meadow degradation on soil hydraulic properties and the corresponding influencing mechanisms are still poorly understood. In this study, soil moisture content (SMC), field capacity (FC) and saturated hydraulic conductivity (Ks) together with several basic soil properties under lightly degraded (LD), moderately degraded (MD) and severely degraded (SD) alpine swamp meadow were investigated; the variations in SMC, FC and Ks with alpine swamp meadow degradation and their dominant influencing factors were analysed. The results showed that SMC and FC decreased consistently from LD to SD, while Ks decreased from LD to MD and then increased from MD to SD, following the order of LD > SD > MD. Significant differences in soil hydraulic properties between degradation degrees were found in the upper soil layers (0-20 cm), indicating that the influences of degradation were most pronounced in the topsoils. FC was positively correlated with capillary porosity, water-stable aggregates, soil organic carbon, and silt and clay content; Ks was positively correlated with non-capillary porosity (NCP). Relative to other soil properties, soil porosity is the dominant factor influencing FC and Ks. Capillary porosity explained 91.1 % of total variance in FC, and NCP explained 97.3 % of total variance in Ks. The combined effect of disappearing root activities and increasing sand content was responsible for the inconsistent patterns of NCP and Ks. Our findings suggest that alpine swamp meadow degradation would

  15. Estimating rumen degradability of forages from semi-natural grasslands, using nylon bag and gas production techniques

    NARCIS (Netherlands)

    Bruinenberg, M.H.; Gelder, van A.H.; Gonzalez Perez, P.; Hindle, V.A.; Cone, J.W.

    2004-01-01

    To determine the ruminal digestion of forages from extensively managed semi-natural grasslands, degradation characteristics and kinetics of silages of three different forages in the rumen of lactating dairy cows were estimated in vitro using the gas production technique (GPT), and in situ using the

  16. 藏北地区草地退化的时空分布特征%Grassland degradation in Northern Tibet based on remote sensing data

    Institute of Scientific and Technical Information of China (English)

    高清竹; 李玉娥; 万运帆

    2006-01-01

    This study selected vegetation cover as the main evaluation index, calculated the grassland degradation index (GDI) and established the remote sensing monitoring and evaluation system for grassland degradation in Northern Tibet, according to the National Standard (GB19377-2003), based on the remote sensing data such as NDVI data derived from NOAA/AVHRR with a spatial resolution of 8km of 1981-2000, from SPOT/VGT with a spatial resolution of 1 km of 2001 and from MODIS with a spatial resolution of 0.25 km of 2002-2004 respectively in this area, in combination with the actual condition of grassland degradation. The grassland degradation processes and their responses to climate change during 1981-2004 were discussed and analyzed in this paper. The result indicated that grassland degradation in Northern Tibet is very serious, and the mean value of GDI in recent 20 years is 2.54 which belongs to the serious degradation grade. From 1981 to 2004, the GDI fluctuated distinctly with great interannual variations in the proportion of degradation degree and GDI but the general tendency turned to severe-grade during this period with the grassland degradation grade changed from light degraded to serious degraded in Northern Tibet. The extremely serious degraded and serious degraded grassland occupied 1.7% and 8.0% of the study area, the moderate and light degraded grassland accounted for 13.2% and 27.9% respectively, and un-degraded grassland occupied 49.2% of the total grassland area in 2004. The grassland degradation was serious, especially in the conjunctive area of Naqu, Biru and Jiali counties, the headstream of the Yangtze River lying in the Galadandong snow mountain and glaciers, the area along the Qinghai-Tibet highway and railway, and areas around the Tanggula and Nianqingtanggula snow mountains and glaciers. So the snow mountains and glaciers as well as their adjacent areas in Northern Tibet were sensitive to climate change and the areas along the vital communication

  17. Exploring effective sampling design for monitoring soil organic carbon in degraded Tibetan grasslands.

    Science.gov (United States)

    Chang, Xiaofeng; Bao, Xiaoying; Wang, Shiping; Zhu, Xiaoxue; Luo, Caiyun; Zhang, Zhenhua; Wilkes, Andreas

    2016-05-15

    The effects of climate change and human activities on grassland degradation and soil carbon stocks have become a focus of both research and policy. However, lack of research on appropriate sampling design prevents accurate assessment of soil carbon stocks and stock changes at community and regional scales. Here, we conducted an intensive survey with 1196 sampling sites over an area of 190 km(2) of degraded alpine meadow. Compared to lightly degraded meadow, soil organic carbon (SOC) stocks in moderately, heavily and extremely degraded meadow were reduced by 11.0%, 13.5% and 17.9%, respectively. Our field survey sampling design was overly intensive to estimate SOC status with a tolerable uncertainty of 10%. Power analysis showed that the optimal sampling density to achieve the desired accuracy would be 2, 3, 5 and 7 sites per 10 km(2) for lightly, moderately, heavily and extremely degraded meadows, respectively. If a subsequent paired sampling design with the optimum sample size were performed, assuming stock change rates predicted by experimental and modeling results, we estimate that about 5-10 years would be necessary to detect expected trends in SOC in the top 20 cm soil layer. Our results highlight the utility of conducting preliminary surveys to estimate the appropriate sampling density and avoid wasting resources due to over-sampling, and to estimate the sampling interval required to detect an expected sequestration rate. Future studies will be needed to evaluate spatial and temporal patterns of SOC variability. Copyright © 2016. Published by Elsevier Ltd.

  18. Small-scale barriers mitigate desertification processes and enhance plant recruitment in a degraded semiarid grassland

    Science.gov (United States)

    Fick, Stephen E; Decker, Cheryl E.; Duniway, Michael C.; Miller, Mark E.

    2016-01-01

    Anthropogenic desertification is a problem that plagues drylands globally; however, the factors which maintain degraded states are often unclear. In Canyonlands National Park on the Colorado Plateau of southeastern Utah, many degraded grasslands have not recovered structure and function >40 yr after release from livestock grazing pressure, necessitating active restoration. We hypothesized that multiple factors contribute to the persistent degraded state, including lack of seed availability, surficial soil-hydrological properties, and high levels of spatial connectivity (lack of perennial vegetation and other surface structure to retain water, litter, seed, and sediment). In combination with seeding and surface raking treatments, we tested the effect of small barrier structures (“ConMods”) designed to disrupt the loss of litter, seed and sediment in degraded soil patches within the park. Grass establishment was highest when all treatments (structures, seed addition, and soil disturbance) were combined, but only in the second year after installation, following favorable climatic conditions. We suggest that multiple limiting factors were ameliorated by treatments, including seed limitation and microsite availability, seed removal by harvester ants, and stressful abiotic conditions. Higher densities of grass seedlings on the north and east sides of barrier structures following the summer months suggest that structures may have functioned as artificial “nurse-plants”, sheltering seedlings from wind and radiation as well as accumulating wind-blown resources. Barrier structures increased the establishment of both native perennial grasses and exotic annuals, although there were species-specific differences in mortality related to spatial distribution of seedlings within barrier structures. The unique success of all treatments combined, and even then only under favorable climatic conditions and in certain soil patches, highlights that restoration success (and

  19. Simulation of Effects of Grassland Degradation on Regional Climate over Sanjiangyuan Region in Qinghai-Tibet Plateau

    Institute of Scientific and Technical Information of China (English)

    LIAN Lishu; SHU Jiong

    2009-01-01

    Regional climate model (RegCM3) was applied to explore the possible effects of land use changes (e.g., grassland degradation in this study) on local and regional climate over the Sanjiangyuan region in the Qinghai-Tibet Plateau. Two multiyear (1991-1999) numerical simulation experiments were conducted: one was a control experiment with current land use and the other was a desertification experiment with potential grassland degradation. Preliminary analysis indicated that RegCM3 is appropriate for simulating land-climate interactions, as the patterns of the simulated surface air temperature, the summer precipitation, and the geopotential height fields are consistent with the observed values. The desertification over the Sanjiangyuan region will cause different climate effects in different regions depending on the surrounding environment and climate characteristics. The area with obvious change in surface air temperature inducing by grassland degradation over the Sanjiangyuan region is located in the Qinghai-Tibet Plateau. A winter surface air temperature drop and the other seasons' surface air temperature increase will be observed over the Qinghai-Tibet Plateau based on two numerical simulation experiments. Surface air temperature changes in spring are the largest (0.46℃), and in winter are the smallest (smaller than 0.03℃), indicating an increasing mean annual surface air temperature over the Qinghai-Tibet Plateau. Surface air temperature changes will be smaller and more complex over the surrounding region, with minor winter changes for the regions just outside the plateau and notable summer changes over the north of the Yangtze River. The reinforced summer heat source in the plateau will lead to an intensification of heat low, causing the West Pacific subtropical high to retreat eastward. This will be followed by a decrease of precipitation in summer. The plateau's climate tends to become warm and dry due to the grassland degradation over the Sanjiangyuan

  20. Physical and chemical degradation of grassland soils in semi-arid regions: A case from Central Anatolia, Turkey

    Science.gov (United States)

    Yaşar Korkanç, Selma; Korkanç, Mustafa

    2016-12-01

    The aim of this study is to determine some hydro-physical and chemical characteristics of soils on the grassland areas under semi-arid conditions in terms of soil degradation processes. Three sampling plots of 20 × 20 m size were selected from the Emen Plain as Locations-I, II and III basing on the area covered with vegetation and visual soil properties; and total 108 soil samples from 2 points and 3 depth levels (0-20 cm, 20-40 cm, 40-60 cm) of each sampling plot. Soils of the research area are in degradation process in terms of some physical and chemical characteristics. It was observed that soil properties (i.e. bulk density, total porosity, organic matter, pH, electrical conductivity and saturated hydraulic conductivity) in Location-II and Location-III changed negatively in comparison to Location-I almost at all depths. In the Location-III grassland, bulk density, pH, electrical conductivity and Na + values are higher than those in Location-I, whereas the organic matter, total porosity and saturated hydraulic conductivity values are low. Grassland area is vulnerable to erosion. High Exchangeable Sodium Percentage (ESP) values in Locations-II and III indicates the sodicity problem in these areas.

  1. Degradation of the Pesticides Mecoprop and Atrazine in Unpolluted Sandy Aquifers

    DEFF Research Database (Denmark)

    Klint, Mikala; Arvin, Erik; Jensen, Bjørn K.

    1993-01-01

    The potential for biodegradation of the pesticides mecoprop ((+/-)-2-(4-chloro-2-methyl-phenoxy)propionic acid) and atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) in an aerobic aquifer was investigated in laboratory batch experiments. The experiments were performed with groundwater...... the aquifer. Atrazine was not degraded during an incubation period of 539 d in groundwater and 174 d in suspensions of groundwater and aquifer sediment. The addition of nutrients, primary substrates (acetate and naphthalene), and a pH or temperature increase had not effect on the recalcitrance of atrazine....

  2. Effect of advective pore water flow on degradation of organic matter in permeable sandy sediment : - A study of fresh- and brackish water

    OpenAIRE

    2005-01-01

    The carbon metabolism in costal sediments is of major importance for the global carbon cycle. Costal sediments are also subjected to physical forcing generating water fluxes above and through the sediments, but how the physical affect the carbon metabolism is currently poorly known. In this study, the effect of advective pore water flow on degradation of organic matter in permeable sandy sediment was investigated in a laboratory study during wintertime. Sediments were collected from both brac...

  3. Phylogeny, Seed Trait, and Ecological Correlates of Seed Germination at the Community Level in a Degraded Sandy Grassland

    OpenAIRE

    Wang, Zhengning; Wang, Lixin; Liu, Zhimin; Li, Yanjuan; Liu, Qingqing; Liu, Bo

    2016-01-01

    Seed germination strongly affects plant population growth and persistence, and it can be dramatically influenced by phylogeny, seed traits, and ecological factors. In this study, we examined the relationships among seed mass, seed shape, and germination percentage (GP), and assessed the extent to which phylogeny, seed traits (seed mass, shape, and color) and ecological factors (ecotype, life form, adult longevity, dispersal type, and onset of flowering) influence GP at the community level. Al...

  4. Phylogeny, Seed Trait, and Ecological Correlates of Seed Germination at the Community Level in a Degraded Sandy Grassland

    Directory of Open Access Journals (Sweden)

    Zhengning Wang

    2016-10-01

    Full Text Available Seed germination strongly affects plant population growth and persistence, and it can be dramatically influenced by phylogeny, seed traits, and ecological factors. In this study, we examined the relationships among seed mass, seed shape, and germination percentage (GP, and assessed the extent to which phylogeny, seed traits (seed mass, shape, and color and ecological factors (ecotype, life form, adult longevity, dispersal type, and onset of flowering influence GP at the community level. All analyses were conducted on the log-transformed values of seed mass and arcsine square root-transformed values of GP. We found that seed mass and GP were significantly negatively correlated, whereas seed shape and GP were significantly positively correlated. The three major factors contributing to differences in GP were phylogeny, dispersal type, and seed shape (explained 5.8%, 4.9% and 3.1% of the interspecific variations independently, respectively, but GP also influenced by seed mass and onset of flowering. Thus, GP was constrained not only by phylogeny but also by seed traits and ecological factors. These results indicated that GP is shaped by short-term selective pressures, and long-term phylogenetic constrains. We suggest that correlates of phylogeny, seed traits, and ecology should be taken into account in comparative studies on seed germination strategies.

  5. Modelling ecogeomorphic feedbacks: investigating mechanisms of land degradation in semi-arid grassland and shrubland

    Science.gov (United States)

    Turnbull, Laura; Mueller, Eva; Tietjen, Britta; Wainwright, John

    2014-05-01

    Across vast areas of the world's drylands, land degradation is exacerbated by ecohydrological processes, which alter the structure, function and connectivity of dryland hillslopes. These processes are often interlinked through feedback mechanisms in such a way that a trigger may result in a re-organization of the affected landscape. Here, we present a spatially explicit process-based ecogeomorphic model, MAHLERAN-EcoHyD to enhance our understanding of complex linkages between abiotic and biotic drivers and processes of degradation in drylands. This ecogeomorphic modelling approach is innovative in two main ways: it couples biotic and abiotic processes, and simulates intra and inter-event dynamics, thus overcoming a key limitation of previous modelling approaches in terms of their temporal scaling, by simulating key ecogeomorphic processes at process-relevant time steps. Redistribution of water, sediment and nutrients during high-intensity rainstorms is simulated at 1-sec time steps, soil moisture and transpiration dynamics at daily time steps, and vegetation dynamics (establishment, growth, mortality) at 14-day time steps, over a high-resolution 1x1 m grid. We use this innovative modelling approach to investigate soil-vegetation feedback mechanisms within a grassland-shrubland transition zone at the Sevilleta Long Term Ecological Research site in the south-western United States. Results from three modelling experiments are presented: the first modelling experiment investigates the impact of annual variations in individual high-intensity storms to assess long-term variations in runoff, soil-moisture conditions and sediment and nutrient fluxes over two decades; the second modelling experiment assesses the impact of vegetation composition on spatial changes in surface soil texture due to soil erosion by water; and the third modelling experiment investigates how long-term changes in vegetation alter feedbacks between biotic and abiotic processes using scenarios for

  6. Effects of different diets on utilization of nitrogen from cattle slurry applied to grassland on a sandy soil in the Netherlands

    NARCIS (Netherlands)

    Reijs, J.W.; Sonneveld, M.P.W.; Sorensen, P.; Schils, R.L.M.; Groot, J.C.J.; Lantinga, E.A.

    2007-01-01

    Dietary adjustments have been suggested as a means to reduce N losses from dairy systems. Differences in fertilizing value of dairy slurry as a result of dietary adjustments were evaluated in a 1-year grassland experiment and by long-term modelling. Slurry composition of non-lactating dairy cows was

  7. Food-Chain Model of Grassland Degradation and Its Restoration Process in Northern Tibet Plateau: A Case Study in Nierong County

    Institute of Scientific and Technical Information of China (English)

    ZHOU Wei; ZENG Yunying; LIU Shuzhen

    2006-01-01

    Based on the model of grassland climate ecological productivity, the process of grassland degradation and its restoration mechanism in northern Tibetan Plateau were discussed by the model of food-chain in which the environmental and human factors were corrected. The results of case study in Nierong County showed that:① the climate trend of becoming warmer, more droughts and gales were conflicted with the restoration of grassland degradation, even under level of perfect management the climate ecological productivity was declined from 89.3 kg/m2 of 1983 to 71.8 kg/m2 of 2003; ② from 1983 to 2003, the population increased fast, while the variation of livestock on hand was little, and the cost of its maintaining is rapid grassland degradation; ③ on the present condition of overgrazing, the livestock on hand can be maintained on the level of theoretical carrying capacity in 2033 by applying the mechanism of food-chain in grassland ecological system controlled with expected coefficients, so that to realize the policy of determining the quantity of livestock according to grass growth.

  8. Three-year changes of surface albedo of degraded grassland and cropland surfaces in a semiarid area

    Institute of Scientific and Technical Information of China (English)

    LIU HuiZhi; TU Gang; DONG WenJie

    2008-01-01

    Diurnal, seasonal and interannual variations of surface albedo of degraded grassland and cropland surfaces at a semiarid area of Tognyu have been investigated based on the continuous three years observational data from 2003 to 2005. The changes of surface albedo with solar elevation angle and soil moisture have been discussed also. It has been found that surface albedo has almost the same diurnal and seasonal variations on degraded grassland and cropland surfaces in the semiarid area, while sur-face albedo is large in winter and small in summer. The diurnal variation of the surface albedo has re-lationship with the weather condition. The diurnal cycle of the surface albedo likes the "U" shape curve in sunny day, while it is low-high after the rain, and high-low after the snow. The surface albedo has large variation in cloudy day, while it has no any variation in overcast day. The large difference of the surface albedo can be 0.04 in winter between two land surfaces, because the snow has large effects on the surface albedo in winter. The rainfall is an important factor in summer on the surface albedo, while the difference of the surface albedo is 0.01 only between two land surfaces. The differences of the surface aibedo can also be 0.04 in autumn due to vegetation growing. The seasonal-average surface albeo from 2003-2005 is 0.25, 0.22, 0.24, 0.32 respectively in spring, summer, autumn and winter on the degraded grassland surface, while it is 0.25, 0.21,0.22, 0.33 respectively in spring, summer, autumn and winter on the cropland surface. The surface albedo becomes smaller with the increase of solar elevation angle. When the solar elevation angle is greater than 40°, the surface albedo changes very little and tends to be a constant. The surface albedo has negative exponent functions with soil moisture in the growing season.

  9. Variation of soil hydraulic properties with alpine grassland degradation in the eastern Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    T. Pan

    2017-05-01

    hydrological effects of vegetation degradation. Further hydrological modelling studies in the Tibetan Plateau and similar regions are recommended to understand the effects of degraded alpine swamp meadows on soil hydraulic properties.

  10. 近30年来青海三江源地区草地退化的时空特征%Grassland degradation in the "Three-River Headwaters" region, Qinghai Province

    Institute of Scientific and Technical Information of China (English)

    刘纪远; 徐新良; 邵全琴

    2008-01-01

    Supported by MSS images in the mid and late 1970s, TM images in the early 1990s and TM/ETM images in 2004, grassland degradation in the "Three-River Headwaters" region (TRH region) was interpreted through analysis on RS images in two time series, then the spatial and temporal characteristics of grassland degradation in the TRH region were ana-lyzed since the 1970s. The results showed that grassland degradation in the TRH region was a continuous change process which had large affected area and long time scale, and rapidly strengthen phenomenon did not exist in the 1990s as a whole. Grassland degradation pattern in the TRH region took shape initially in the mid and late 1970s. Since the 1970s, this deg-radation process has taken place continuously, obviously characterizing different rules in different regions. In humid and semi-humid meadow region, grassland firstly fragmentized, then vegetation coverage decreased continuously, and finally "black-soil-patch" degraded grassland was formed. But in semi-arid and arid steppe region, the vegetation coverage de-creased continuously, and finally desertification was formed. Because grassland degradation had obviously regional differences in the TRH region, it could be regionalized into 7 zones, and each zone had different characteristics in type, grade, scale and time process of grass- land degradation.

  11. Effect of Land Cover Change on Soil Phosphorus Fractions in Southeastern Horqin Sandy Land, Northern China

    Institute of Scientific and Technical Information of China (English)

    ZHAO Qiong; ZENG De-Hui; FAN Zhi-Ping; D.K.LEE

    2008-01-01

    In the past 50 years, large areas of the Horqin sandy land were afforested to prevent desertification. Although the afforestation policy appears successful, many people now doubt whether it is suitable to plant trees with high density on the poor soils in semiarid regions. Little is known about the impacts of afforestation on the sandy soil properties, although the evaluation of these impacts is fundamental to judge the rationality of afforestation policy. Soil phosphorus (P) fractions, acid phosphomonoesterase activities, and other soil chemical properties were compared among five adjoining typical ecosystems on poor sandy soils in southeastern Horqin sandy land. The ecosystems studied are natural elm savanna, degraded grassland, Mongolian pine (Pinus sylvestris var. Mongolica) plantation, Chinese pine (Pinus tabulaeformis) plantation, and mixed plantation of Mongolian pine and poplar (Populus simonii). The results showed that organic P dominated soil P (47%-65%) was the principal source of available P. The degradation of elm savanna to grassland significantly reduced soil pH and resulted in an overall reduction in soil fertility, although slightly increased labile inorganic P. Grassland afforestation had no significant influence on soil pH, organic carbon, and total N but significantly reduced total P. Impacts of grassland afforestation on soil P fractions depended on tree species. Natural elm savanna had higher soil P conserving ability than artificial plantations. Therefore, with the aim of developing a sustainable ecosystem, we suggested that vegetations with low nutrient demand (particularly P) and efficient nutrient cycling would be more suitable for ecosystem restoration in the semiarid region.

  12. Pasture degradation modifies soil organic matter properties and biochemical functioning in Tibetan grasslands

    Science.gov (United States)

    Spielvogel, Sandra; Steingräber, Laura; Schleuß, Per; Kuzyakov, Yakov; Guggenberger, Georg

    2015-04-01

    Kobresia pastures of the Tibetan Plateau represent the world's largest alpine ecosystem. Moderate husbandry on Kobresia pastures is beneficial for the storage of soil organic carbon (OC), nitrogen (N) and other nutrients and prevents erosion by establishment of sedge-turf root mats with high OC allocation rates below ground. However, undisturbed root mats are affected by freezing and thawing processes, which cause initial ice cracks. As a consequence decomposition of root mat layers will be accelerated and current sedentarization programs with concomitant increased grazing intensity may additionally enhance root mat degradation. Finally, cracks are enlarged by water and wind erosion as well as pika activities until bare soil surface areas without root mat horizons occur. The aim of this study was to understand the impact of the root mat layer on soil organic carbon stabilization and microbial functioning depending on soil depths and to predict future changes (OC, N and nutrient losses, soil microbial functioning in SOM transformation) by overgrazing and climate change. We investigated the mineral soil below Kobresia root mats along a false time degradation sequence ranging from stage 1 (intact root mat) to stage 4 (mats with large cracks and bare soil patches). Vertical gradients of δ13C values, neutral sugar, cutin and suberin contents as well as microbial biomass estimated by total phospholipid fatty acid (PLFA), microbial community composition (PLFA profiles) and activities of six extracellular enzymes involved in the C, N, and P cycle were assessed. Soil OC and N contents as well as C/N ratios indicate an increasing illuviation of topsoil material into the subsoil with advancing root mat degradation. This was confirmed by more negative δ13C values as well as significantly (p ≤ 0.05) increasing contributions of cutin derived hydroxy fatty acids to OC in the subsoils from degradation stages 1 to 4. PLFA profiles were surprisingly similar in the subsoils of

  13. Three-year Variations of Water, Energy and CO2 Fluxes of Cropland and Degraded Grassland Surfaces in a Semi-arid Area of Northeastern China

    Institute of Scientific and Technical Information of China (English)

    LIU Huizhi; TU Gang; FU Congbin; SHI Liqing

    2008-01-01

    Based on 3 years (2003-05) of the eddy covariance (EC) observations on degraded grassland and cropland surfaces in a semi-arid area of Tongyu (44°25'N, 122°52'E, 184 m a.s.l.), Northeast China, seasonal and annual variations of water, energy and CO2 fluxes have been investigated. The soil moisture in the thin soil layer (at 0.05, 0.10 and 0.20 m) clearly indicates the pronounced annual wet-dry cycle; the annual cycle is divided into the wet (growing season) and dry seasons (non-growing season). During the growing season (from May to September), the sensible and latent heat fluxes showed a linear dependence on the global solar radiation. However, in the non-growing season, the latent heat flux was always less than 50 W m-2, while the available energy was dissipated as sensible, rather than latent heat flux. During the growing season in 2003-05, the daily average sensible and latent heat fluxes were larger on the cropland surface than on the degraded grassland surface. The cropland ecosystem absorbed more CO2 than the degraded grassland ecosystem in the growing season in 2003-05. The total evapotranspiration on the cropland was more than the total precipitation, while the total evapotranspiration on the degraded grassland was almost the same as the total annual precipitation in the growing season. The soil moisture had a good correlation with the rainfall in the growing season. Precipitation in the growing season is an important factor on the water and carbon budget in the semi-arid area.

  14. High-quality draft genome sequence of Enterobacter sp. Bisph2, a glyphosate-degrading bacterium isolated from a sandy soil of Biskra, Algeria.

    Science.gov (United States)

    Benslama, Ouided; Boulahrouf, Abderrahmane

    2016-06-01

    Enterobacter sp. strain Bisph2 was isolated from a sandy soil from Biskra, Algeria and exhibits glyphosate-degrading activity. Multilocus sequence analysis of the 16S rRNA, rpoB, hsp60, gyrB and dnaJ genes demonstrated that Bisph2 might be a member of a new species of the genus Enterobacter. Genomic sequencing of Bisph2 was used to better clarify the relationships among Enterobacter species. Annotation and analysis of the genome sequence showed that the 5.535.656 bp genome of Enterobacter sp. Bisph2 consists in one chromosome and no detectable plasmid, has a 53.19% GC content and 78% of genes were assigned a putative function. The genome contains four prophages of which 3 regions are intact and no CRISPER was detected. The nucleotide sequence of this genome was deposited into DDBJ/EMBL/GenBank under the accession JXAF00000000.

  15. Characteristics of grassland degradation and driving forces in the source region of the Yellow River from 1985 to 2000%黄河源地区草地退化空间特征

    Institute of Scientific and Technical Information of China (English)

    刘林山; 张镱锂; 摆万奇

    2006-01-01

    The source region of the Yellow River is located in the middle east of the Tibetan Plateau in northwest China. The total area is about 51,700 km2, mainly covered by grassland (79%), unused land (16%) and water (4%). The increasing land utilization in this area has increased the risk of environmental degradation. The land use/cover data (1985 and 2000) provided by the Data Center of Resources and Environment in the Chinese Academy of Sciences were used to analyze the land cover change in the source region of the Yellow River. DEM (1:250,000) data, roads and settlement data were used to analyze the spatial characteristics of grasslands degradation. The ArcGIS 9 software was used to convert data types and do the overlay, reclassification and zonal statistic analysis. Results show that grassland degradation is the most important land cover change in the study area, which occupied 8.24% of the region's total area. Human activities are the main causes of the grassland degradation in the source region of the Yellow River: 1) the degradation rate is higher on the sunny slope than on the shady slope; 2) the grassland degradation rate decreases with an increase in the elevation, and it has a correlation coefficient of -0.93; 3) the nearer to the settlements the grassland is, the higher the degradation rate. Especially within a distance range of 12 km to the settlements, the grassland degradation rate is highly related with the distance, with a coefficient of -0.99; and 4) in the range of 4 km, the degradation rate decreases with the increase of distance to the roads, with a correlation coefficient of -0.98. Besides some physical factors,human activities have been the most important driving forces of the grassland degradation in the source region of the Yellow River since 1985. To resolve the degradation problems, population control is essential, and therefore, it can reduce the social demand of livestock products from the grassland. To achieve sustainable development, it

  16. Artificial Management Improves Soil Moisture, C, N and P in an Alpine Sandy Meadow of Western China

    Institute of Scientific and Technical Information of China (English)

    WU Gao-Lin; LI Wei; ZHAO Ling-Ping; SHI Zhi-Hua

    2011-01-01

    Regeneration of degraded grassland ecosystems is a significant issue in restoration ecology globally.To understand the effects of artificial management measures on alpine meadows, we surveyed topsoil properties including moisture, organic carbon (SOC), nitrogen (N), and phosphorus (P) contents five years after fencing and fencing + reseeding management practices in a sandy meadow in the eastern Qinghai-Tibetan Plateau, northwestern China.Both the fencing and fencing + reseeding management practices significantly increased soil moisture storage, SOC, total N, available N, total P, and available P, as compared to the unmanaged control.Fencing plus reseeding was more effective than fencing alone for improving soil C, N, and P contents.These suggested that rehabilitation by reseeding and fencing generally had favorable effects on the soil properties in degraded sandy alpine meadows, and was an effective approach for restoration of degraded meadow ecosystems of the Qinghai-Tibetan Plateau.

  17. Causes of alpine grassland degradation and its restoration strategy in Tianzhu County%天祝高寒草地退化原因分析与治理策略

    Institute of Scientific and Technical Information of China (English)

    徐长林; 鱼小军

    2011-01-01

    Tianzhu County with vast alpine grassland is one of Gansu province's important pastoral areas. This study reviewed the causes of grassland degradation at broad and home, and then proposed that the fragile ecological environment was the intrinsic factors, which caused alpine grassland to degrade in the Tianzhu County. The human activities such as disturbance and unreasonable utilization were the major driver for grassland degradation, and global warming accelerated the grassland degradation. This study also proposed that the loss of livestock manure, allelopathy among plants and self-allelopathy were important causes of grassland degradation. Finally, this study put forward some measures to restore the degraded alpine grassland, which included rational carrying capacity and the increase of marketing rate for livestock, and include fencing and establishment of artificial grassland for improvement grassland. Meanwhile, the rodents and pests integrated control, intellectual restoration , and extension of science and technology would be benefit the restoration of alpine grassland reviewed.%天祝高寒草地是甘肃省重要的牧区之一。借鉴国内外相关研究进展,综合认为脆弱的生态环境是天祝高寒草地退化的内因,人类不合理的利用和干扰是高寒草地退化的主要驱动力,气候变暖、变干加速了高寒草地的退化。并认为家畜粪便的流失、植物的化感作用和自毒作用也是导致天祝高寒草地退化的原因。提出了天祝高寒草地的整体治理策略,即以草定畜、提高出栏率,轻度和中度退化草地进行草地改良、围栏,重度退化草地进行栽培草地建植,同时结合草地鼠害综合治理、加强人才建设与加快科技成果推广和转化。

  18. Grassland degradation with C-D and Chow model in Plateau Pasture:a case of Maqu Pasture%高寒牧区草地沙化问题研究——以玛曲草原为例

    Institute of Scientific and Technical Information of China (English)

    王庆辉; 窦学诚; 龚大鑫

    2012-01-01

    针对玛曲草原草地退化问题,运用Cobb-Douglas生产函数和Chow分割点检验定量分析原料型畜牧业和制度对草地沙化的影响,并得出制度是导致草地沙化的根本原因;针对存在的问题,运用环境机会论探索可持续的生产、经营和管理模式。通过优化发展模式,实现经济发展与草原生态的良性循环,为其他高原牧区畜牧业经济发展提供借鉴意义。%Maqu grassland,belong to Maqu County,Annan Prefecture,Gansu Province,China and located at eastern fringe of Qinhai-Tibet Plateau,is important to the water supply area of Yellow River,but grassland desertification in the region had an vicious effect on this function.This paper aims at the problem of grassland degradation in Maqu pasture,quantitatively analyses reasons for the grassland degradation from natural and artificial factors by applying Cobb-Douglass production function,concludes that the artificial factors are the main reason to cause grassland degradation.The paper further analyzes the artificial factors from three aspects of the raw material model of animal husbandry,operations management system and implementation mechanism,and considers that the institution is the root reason of grassland degradation by applying the method of Chow breakpoint test.The relationship between the institution of grassland property right and over-gazing is consanguineous,and the design of the institution of property right is faultiness and institution provided is lagging,which makes utilization and protection of grassland out-of-order,tempts herd to over-manage grassland,and leads grassland to be overgrazed over long time.For the existent problems,the paper explores sustainable model of production,operation and management by environmental opportunity,and proposes the sustainable development models of eco-cultural tourism,partnerships system and government management and religious propaganda combined.By optimizing development model to realize

  19. Soil disturbance as a grassland restoration measure

    DEFF Research Database (Denmark)

    Schnoor, Tim; Bruun, Hans Henrik; Olsson, Pål Axel

    2015-01-01

    to experimental disturbance treatments (ploughing or rotavation), and the vegetation was surveyed during four subsequent years of succession. Treated plots were compared with control plots representing untreated grassland, as well as nearby plots characterized by plant communities representing the restoration...... target. Species richness and functional diversity both increased in response to soil disturbance, and rotavation, but not ploughing, had a persistent positive effect on the occurrence of specialist species of calcareous sandy grassland. However, no type of soil disturbance caused the plant species...

  20. Soil disturbance as a grassland restoration measure-effects on plant species composition and plant functional traits.

    Directory of Open Access Journals (Sweden)

    Tim Schnoor

    Full Text Available Soil disturbance is recognized as an important driver of biodiversity in dry grasslands, and can therefore be implemented as a restoration measure. However, because community re-assembly following disturbance includes stochastic processes, a focus only on species richness or establishment success of particular species will not inform on how plant communities respond ecologically to disturbance. We therefore evaluated vegetation development following disturbance by quantifying species richness, species composition and functional trait composition. Degraded calcareous sandy grassland was subjected to experimental disturbance treatments (ploughing or rotavation, and the vegetation was surveyed during four subsequent years of succession. Treated plots were compared with control plots representing untreated grassland, as well as nearby plots characterized by plant communities representing the restoration target. Species richness and functional diversity both increased in response to soil disturbance, and rotavation, but not ploughing, had a persistent positive effect on the occurrence of specialist species of calcareous sandy grassland. However, no type of soil disturbance caused the plant species composition to develop towards the target vegetation. The disturbance had an immediate and large impact on the vegetation, but the vegetation developed rapidly back towards the control sites. Plant functional composition analysis indicated that the treatments created habitats different both from control sites and target sites. Community-weighted mean Ellenberg indicator values suggested that the observed plant community response was at least partially due to an increase in nitrogen and water availability following disturbance. This study shows that a mild type of disturbance, such as rotavation, may be most successful in promoting specialist species in calcareous sandy grassland, but that further treatments are needed to reduce nutrient availability. We

  1. Soil disturbance as a grassland restoration measure-effects on plant species composition and plant functional traits.

    Science.gov (United States)

    Schnoor, Tim; Bruun, Hans Henrik; Olsson, Pål Axel

    2015-01-01

    Soil disturbance is recognized as an important driver of biodiversity in dry grasslands, and can therefore be implemented as a restoration measure. However, because community re-assembly following disturbance includes stochastic processes, a focus only on species richness or establishment success of particular species will not inform on how plant communities respond ecologically to disturbance. We therefore evaluated vegetation development following disturbance by quantifying species richness, species composition and functional trait composition. Degraded calcareous sandy grassland was subjected to experimental disturbance treatments (ploughing or rotavation), and the vegetation was surveyed during four subsequent years of succession. Treated plots were compared with control plots representing untreated grassland, as well as nearby plots characterized by plant communities representing the restoration target. Species richness and functional diversity both increased in response to soil disturbance, and rotavation, but not ploughing, had a persistent positive effect on the occurrence of specialist species of calcareous sandy grassland. However, no type of soil disturbance caused the plant species composition to develop towards the target vegetation. The disturbance had an immediate and large impact on the vegetation, but the vegetation developed rapidly back towards the control sites. Plant functional composition analysis indicated that the treatments created habitats different both from control sites and target sites. Community-weighted mean Ellenberg indicator values suggested that the observed plant community response was at least partially due to an increase in nitrogen and water availability following disturbance. This study shows that a mild type of disturbance, such as rotavation, may be most successful in promoting specialist species in calcareous sandy grassland, but that further treatments are needed to reduce nutrient availability. We conclude that a

  2. Modelling nutrient dynamics during runoff events over a trajectory of land degradation from semi-arid grassland to shrubland in the south-western USA

    Science.gov (United States)

    Brazier, R. E.; Turnbull, L.; Wainwright, J.

    2009-04-01

    Land degradation in arid and semi-arid areas, such as the invasion of grasslands by shrubs, is often associated with an increase in runoff and erosion and a change in nutrient dynamics. Modelling of nutrient dynamics during runoff events (in particular particulate-bound nutrients), is particularly important, since the spatial redistribution of nutrients (in addition to water and sediment) can have significant implications for vegetation dynamics in these ecosystems. In this study, MAHLERAN (Model for Assessing Hillslope to Landscape Runoff, Erosion and Nutrients) is extensively evaluated against runoff and erosion data from four plots (representative of different stages of land degradation) over a transition from grassland to shrubland at the Sevilleta National Wildlife Refuge in New Mexico, USA. MAHLERAN already simulates dissolved nutrient dynamics (based on an advection-dispersion model of N and P). A new particulate-bound nutrient module was developed to include a representation of particulate-bound nutrient dynamics which is an important form of nutrient transport in these ecosystems. Understanding dynamics of both dissolved and particulate-bound nutrient dynamics during runoff events is imperative, because of their differing roles in terms of nutrient bioavailability and potential implications for plant dynamics. MAHLERAN was evaluated against runoff, erosion and nutrient data that was collected from the four plots over the transition from grassland to shrubland. Results of the model evaluation show that the runoff and erosion components of MAHLERAN perform well, as does the new particulate-bound nutrient submodel. However, since the particulate-bound nutrient submodel is effectively a bolt-on to the erosion model, the performance of the particulate-bound nutrient model is dependent on the performance of the erosion component of MAHLERAN. The performance of the dissolved nutrient component of MAHLERAN was abysmal, which indicates that the process

  3. Soil bacterial community responses to revegetation of moving sand dune in semi-arid grassland.

    Science.gov (United States)

    Cao, Chengyou; Zhang, Ying; Cui, Zhenbo; Feng, Shuwei; Wang, Tingting; Ren, Qing

    2017-08-01

    Grasslands in semi-arid Northern China are widely desertified, thus inducing the formation of a large area of moving sand lands. Revegetation of the sandy land is commonly adopted to restore degraded grasslands. The structure of the soil microbial community might dramatically change during degradation and recovery because microorganisms are one of the major drivers of ecological process through their interactions with plants and soil. Assuming that soil properties are the key determinants of the structure of soil bacterial community within the same soil type, whether the vegetation type causes the significant difference in the structure of soil bacterial community during revegetation and restoration of the degraded grasslands remains poorly understood. Our study aimed to (1) investigate the response of soil bacterial communities to the changes during vegetation degradation and recovery and (2) evaluate whether the soil bacterial communities under plantations return to their native state. We detected the shifts in diversities and compositions of the soil bacterial communities and the relative abundance of dominant bacterial taxa by using the high-throughput Illumina MiSeq sequencing technique in an area covered by 32-year-old Caragana microphylla, Artemisia halodendron, Hedysarum fruticosum, Pinus sylvestris var. mongolica, Populus simonii, and Salix gordejevii sand-fixing plantations and in the native community (NC) dominated by elm, and moving sandy dune (MS). We found that the obtained operational taxonomic units by 16S rRNA gene sequencing and diversity index in MS were all significantly lower than those in NC, and the number and composition of dominant genera were significantly different between NC and MS. Interestingly, the compositions of bacterial communities and the dominant genera in different sand-fixation plantations (C. microphylla, A. halodendron, H. fruticosum, P. sylvestris var. mongolica, P. simonii, and S. gordejevii) were all similar to those of

  4. Rutog Grasslands

    Institute of Scientific and Technical Information of China (English)

    YANEFNG

    2005-01-01

    The Rutog Grasslands lie at the foot of Milha in between the Lhasa and Gongbo areas,and are relatively close to Lhasa. To appreciate the scenery there, we left the Lhasa River Valley, and struck out upstream along the Mezhumi River to the Wose River that cuts through the Rutog Grasslands.

  5. Hurricane Sandy and earthquakes

    OpenAIRE

    MAVASHEV BORIS; MAVASHEV IGOR

    2013-01-01

    Submit for consideration the connection between formation of a hurricane Sandy and earthquakes. As a rule, weather anomalies precede and accompany earthquakes. The hurricane Sandy emerged 2 days prior to strong earthquakes that occurred in the area. And the trajectory of the hurricane Sandy matched the epicenter of the earthquakes. Possibility of early prediction of natural disasters will minimize the moral and material damage.

  6. A toxic endophyte-infected grass helps reverse degradation and loss of biodiversity of over-grazed grasslands in northwest China.

    Science.gov (United States)

    Yao, Xiang; Christensen, Michael J; Bao, Gensheng; Zhang, Chunping; Li, Xiuzhang; Li, Chunjie; Nan, Zhibiao

    2015-12-18

    Overgrazing of China's grasslands is increasingly causing biodiversity to decline. In degenerated grasslands of northwest China endophyte (Epichloё gansuensis) infected Achnatherum inebrians (drunken horse grass) is becoming widely distributed because of its toxicity to livestock. In this study, we investigated the ecological consequences of endophyte toxicity in this native grass, at three sites in northwest China, by comparing seed production of plant species and arthropod abundance in overgrazed grasslands with and without the presence of A. inebrians. Our findings demonstrate that the presence of endophyte infected A. inebrians reduces the loss of plant and arthropod biodiversity by providing a protected nursery free of animal grazing. Therefore, A. inebrians, typically regarded as an unwanted toxic invader by pastoralists, should be viewed as beneficial for grasslands as its presence maintains plant and arthropod biodiversity, and provides a foundation stone in the reconstruction and restoration of these grassland ecosystems.

  7. Soil disturbance as a grassland restoration measure

    DEFF Research Database (Denmark)

    Schnoor, Tim; Bruun, Hans Henrik; Olsson, Pål Axel

    2015-01-01

    Soil disturbance is recognized as an important driver of biodiversity in dry grasslands, and can therefore be implemented as a restoration measure. However, because community re-assembly following disturbance includes stochastic processes, a focus only on species richness or establishment success...... target. Species richness and functional diversity both increased in response to soil disturbance, and rotavation, but not ploughing, had a persistent positive effect on the occurrence of specialist species of calcareous sandy grassland. However, no type of soil disturbance caused the plant species...

  8. Florística e fitossociologia da vegetação de um campo sujeito à arenização no sudoeste do Estado do Rio Grande do Sul, Brasil Floristics and phytosociology of grassland vegetation subject to sandy desertification in southwestern Rio Grande do Sul State, Brazil

    Directory of Open Access Journals (Sweden)

    Elisete Maria de Freitas

    2009-06-01

    Full Text Available Extensas áreas de campo nativo do sudoeste do Rio Grande do Sul são suscetíveis ao processo de arenização, que ocorre em áreas de fragilidade pedológica, tendo influência de interferência antrópica e fatores abióticos. Com o objetivo de testar a variação da cobertura vegetal e a dinâmica da arenização no tempo e conforme a influência da distância da encosta, foi desenvolvido um estudo florístico e fitossociológico em áreas de campo nativo sob pastejo. Duas subáreas, diferentes quanto ao processo da arenização, foram selecionadas no município de São Francisco de Assis, RS. O levantamento florístico apontou a ocorrência de 102 espécies, distribuídas em 25 famílias. No estudo fitossociológico, 35 quadros permanentes de 0,25 m² em cada subárea foram dispostos em diferentes distâncias da encosta do morro. Foram registradas as coberturas das espécies vegetais, do mantilho e do solo exposto em três períodos. Dados sobre riqueza e diversidade de espécies e formas de vida foram avaliados por análise de variância, via testes de aleatorização, considerando o fator temporal e o espacial (distância da encosta. Houve maior redução da diversidade específica e da cobertura vegetal na subárea 1 (com menor cobertura vegetal conforme a variação temporal. Na subárea 2 (com maior cobertura vegetal, o aumento do solo exposto e a conseqüente redução da cobertura vegetal tiveram maior influência da distância da encosta. A alteração da cobertura vegetal e a expansão da arenização observadas ao longo do tempo são resultado da influência conjunta da dinâmica pluviométrica, do tipo solo, da presença de encostas dos relevos tabulares com pouca vegetação e da contínua pressão de pastejo.Extensive areas of native grassland in southwestern Rio Grande do Sul are susceptible to sandy desertification, which occurs in pedologically fragile areas influenced by anthropic interference and abiotic factors. A

  9. Analyzing Hurricane Sandy

    Science.gov (United States)

    Convertino, Angelyn; Meyer, Stephan; Edwards, Becca

    2015-03-01

    Post-tropical Storm Sandy underwent extratropical transition shortly before making landfall in southern New Jersey October 29 2012. Data from this system was compared with data from Hurricane Ike (2008) which represents a classic hurricane with a clear eye wall and symmetry after landfall. Storm Sandy collided with a low pressure system coming in from the north as the hurricane made landfall on the US East coast. This contributed to Storm Sandy acting as a non-typical hurricane when it made landfall. Time histories of wind speed and wind direction were generated from data provided by Texas Tech's StickNet probes for both storms. The NOAA Weather and Climate program were used to generate radar loops of reflectivity during the landfall for both storms; these loops were compared with time histories for both Ike and Sandy to identify a relationship between time series data and storm-scale features identified on radar.

  10. Study on soil seed bank of different alpine degraded grasslands in Nakchu area of Tibet%西藏那曲不同高寒退化草地土壤种子库研究

    Institute of Scientific and Technical Information of China (English)

    王宏辉; 孙磊; 赵玉红; 赵改红; 李龙; 魏学红

    2012-01-01

    【Objective】In order to provide some background knowledge for vegetation restoration,productivity and ecological protection of degraded grasslands in Nakchu area of Tibet,soil feed bank,the number of fermentable seeds,and the ecological characteristics in different degraded grasslands of Nakchu were systematically investigated.【Method】Based on vegetation coverage,plots of four different degradation levels (light degradation,medium degradation,heavy degradation and extremely severe degration)were selected.In four plots which were selected using line transect method,soils with volume of 10 cm×10 cm×10 cm (including litters) were taken as seed bank sample on the first day of each month .The soil was immersed,dissolved and sifted to separate seeds,and the separated seeds were appraised and counted.Then the amount of germinative seeds of soil seed bank was mensured by germination test in the lab.The influence of different mass fractions of GA3(0.10%,0.05% and 0.02%),KNO3(0.20%),H2SO4(60%,70%,80% and 90%)treatment of seed bank on seed germination was analyzed.The importance value of soil bank was calculated through its relative coverage,relative frequency,relative density and relative biomass.The composition and characteristics of plant community of soil bank was also analyzed.【Result】The results showed that the largest number of seeds (530±80.00)grains/m^2 was obtained in the medium degraded meadow in Nakchu,followed by heavy and extremely severe degradation grasslands (250±44.72)grains/m^2,while medium degraded grassland’s seed stock was the least (216±21.34)grains/m^2.Most species in the seed banks were the Rosaceae,Compositae,Gramineae,and so on.Under laboratory conditions,the number of seeds that could germinate was the least in the seed bank of medium degraded grassland(100±0.00)grains/m^2,followed by heavily and extremely severe degraded grasslands,and the largest number of seeds that could germinate was obtained in the medium degraded

  11. 近15a来黄河源地区玛多县草地植被退化的遥感动态监测%Monitoring grassland degradation dynamically at Maduo County in source region of Yellow River in past 15 years based on remote sensing

    Institute of Scientific and Technical Information of China (English)

    徐剑波; 宋立生; 赵之重; 胡月明; 刘畅

    2012-01-01

    The Yellow River source region, as the headwater of the Yellow River, where the ecological environment is sensitive and vulnerable, is located in hinterland of the Qinhai -Tibet Plateau. It is of significant importance to protecting and constructing natural protection of "Three-River Headwater" by using remote sensing to monitor dynamically the grassland degradation in different temporal and spatial scale in this region. Grassland degradation refers to the overall reduction in grassland productivity as a consequence of human activities and natural processes. It represents the decline of grassland quality, density of grass cover, productivity, service function, or an increase in unpalatable grass species, and even as denudation of underlying soil. Compared with conventional grassland degradation researches, which are through field investigation to identify contributing factors and then each of the factors was graded and combined, remote sensing is much more efficient in assessing grassland degradation. Accorded to the national standard of China( GB19377 -2003) and actual condition of grassland degradation in the Maduo County in the source region of the Yellow River, this study selected vegetation cover, pasture plant height, aboveground biomass, palatable pasture proportion, soil organic matter as the 5 evaluation indices. Then the calculation models were established based on the remote sense and in situ measured data, to monitor and evaluate grassland degradation in that region. Because of differential sampling sizes on the ground and space, the 5 evaluation indices cannot be directly quantified from TM imageries based on concurrently collected samples over 1 m2 plots. So, significant regression models were used to set relation between in situ measured data and TM bands-derived index values. However, for the evaluation indices of pasture plant height and palatable pasture proportion, there is weak correlation between in situ measured data and remote sensing. In

  12. [Effects of land use and management on soil quality of Heerqin sandy land].

    Science.gov (United States)

    Su, Yongzhong; Zhao, Halin

    2003-10-01

    The changes of soil physical, chemical and biological properties under different land use and management lasted for 14 years were investigated on the Heerqin sandy land. The results showed that among various land use systems marked differences exhibited in soil quality indicators, including soil particle composition, porosity distribution, bulk density, water-holding capacity, organic matter and nutrient contents, pH, and enzyme activities. Most of these soil quality indicators were the highest in the orchard intercropped with crops and perennial grass (agroforestry systems), intermediate in the well-management irrigated farmland, and the lowest in the less-management dry farmland. Compared to the primary grassland soil, although some soil properties, including porosity distribution, water-holding capacity, phosphorus content, and enzyme activities, were improved in the well-management systems, soil organic matter and nitrogen contents were significantly lower. It suggested that a long-term input of organic matter was needed for the restoration and reestablishment of soil carbon and nitrogen pools in the seriously degraded ecosystem. Inappropriate land use and management could rapidly worsen soil quality, and hence, from a perspective of soil resource conservation, a preferable way for preventing soil degradation and achieving sustainable land use should be to give up the cultivation of degraded dry farmlands, and to adopt more effective and appropriate soil management and cultivation practices.

  13. Needles stable carbon isotope composition and traits of Pinus sylvestris var.mongolica in sparse wood grassland in south edge of Keerqin Sandy Land under the conditions of different precipitation%不同降水条件下科尔沁沙地南缘疏林草地樟子松针叶δ13C和叶性状特征

    Institute of Scientific and Technical Information of China (English)

    宋立宁; 朱教君; 李明财; 闫涛; 张金鑫

    2012-01-01

    通过比较不同自然降水年份(极端干旱和极端湿润)19年生疏林草地樟子松的针叶δ13C、比叶面积和干物质含量,结合土壤含水量和地下水埋深,探讨了极端降水对樟子松水分利用的影响.结果表明:干旱年份(2009)樟子松林土壤含水量显著低于湿润年份(2010),但樟子松当年生针叶的δ13C在两年间没有显著差异,且两年相同月份间亦无显著差异;干旱年份当年生针叶的比叶面积显著低于湿润年份,而不同年份间干物质含量的差异不显著.在两种极端降水条件下,樟子松的水分利用效率没有明显变化,主要通过改变当年生针叶的比叶面积来适应降水量的变化.对于地下水埋深高于3.0m的疏林草地樟子松人工林生态系统,极端干旱不会严重影响樟子松的存活和生长.%A comparative study was conducted on the needles stable carbon isotope composition (δ13C) , specific leaf area (SLA) , and dry matter content (DMC) of 19-year-old Pinus sylvestris var. mongolica trees in a sparse wood grassland in the south edge of Keerqin Sandy Land under the conditions of extreme drought and extreme wetness, aimed to understand the water use of Pinus sylvestris under the conditions of extreme precipitation. The soil water content and groundwater level were also measured. In the dry year (2009 ) , the soil water content in the grassland was significantly lower than that in the wet year (2010) , but the δ13C values of the current year-old needles had no significant difference between the two years and between the same months of the two years. The SLA of the current year-old needles was significantly lower in the dry year than in the wet year, but the DMC had no significant difference between the two years. Under the conditions of the two extreme precipitations, the water use efficiency of the trees did not vary remarkably, and the trees could change their needles SLA to adapt the variations of precipitation. For

  14. RESTORATION DYNAMICS OF COMMUNITY FEATURE AND DIVERSITY IN DEGRADED DRY- GRASSLAND%退化典型干草原群落特征与多样性的恢复动态

    Institute of Scientific and Technical Information of China (English)

    李兰花; 高永; 孙树光

    2011-01-01

    对退化草原自然恢复演替过程植被变化的研究,是认识其恢复过程、机理、探讨恢复的限制因子和进一步制定快速、低投入生态恢复措施的基础.通过对内蒙古典型干草原地带退化草原[冷蒿(Artemisia frigida)、百里香(Thymus serpyllum)和糙隐子草(Cleistogenes squarrosa等为主]禁牧8a的恢复过程研究表明:在退化草原群落自然恢复过程中,植物高度上升;植被盖度和生物量增加;物种数先增加后降低逐渐趋于稳定.群落的物种多样性和均匀度先明显增长后趋于平缓稍微有所下降,物种丰富度和优势度先增加后减少再增加再减少,这一变化与该区草原植被特质及人为干扰活动有关.即在禁牧初期,一些1、2a生植物的侵入,以及退化群落中建群种、优势种得以优先恢复,所以植物群落各特征都呈增长趋势;而随着禁牧年限的增长,草原群落结构趋于稳定,各植被生态特征变化都呈平稳波动.%Studied vegetation change of the degraded grasslands can provide knowledges on the restoration processes and mechnisms, reveal the factors liminting restoration, and is further a base for making ecological measures for fast restoration with the lowest input. The natural restoration of a degraded grassland dominated by Artemisia frigida, Thymus serpyllum and Cleistogenes squarrosa were researched in the Xilamuren dry - grassland zone,Inner Mongolia. Tresults showed that, through eight years banning grazing,the height of grassland community greatly increased; and its coverage, biomass and species had an increase, but species had a decrease in banning grazing five years. The species diversity and community evenness had a marked increas at first,and then a decrease; species richness and ecological dominance had a complex wavy change, the reason of this change was the grassland feature and people actions. Early in the banning grazing, intrusion of some annual and biennial plants and

  15. Preliminary Study for the Influences of Grassland Degradation on Soil Water Retention in the Source Region of the Yellow River%黄河源区草地退化对土壤持水性影响的初步研究

    Institute of Scientific and Technical Information of China (English)

    易湘生; 李国胜; 尹衍雨; 王炳亮

    2012-01-01

    在黄河源区草地退化严重的玛沁县军牧场地区,采用不同草地退化样地对比的方法,开展草地退化对土壤持水性影响研究。结果表明:①毛管持水量和饱和含水量在0~10cm土层以无退化草地最大,极度退化草地最小,而在10~20cm土层,两者在不同退化草地之间差异不明显,仍以极度退化草地最小,但两者在20~30cm土层以轻度和重度退化草地较大,无退化和中度退化草地相对较小;②在土壤表层(0~10cm),无退化草地的田间持水量远大于其他退化草地,轻度和重度退化草地田间持水量较大,极度退化草地最小,而在10cm以下土层,田间持水量以轻度和重度退化草地较大,无退化和中度退化草地相对较小;③各土壤持水量与土壤理化性质关系密切,主要受容重、总碳、有机质和总氮这4个因素影响;④不同草地退化程度下地表覆被状况、植物根系生物量以及分布特征引起土壤容重、有机质等发生变化,可能是进一步导致土壤持水性差异的主要原因。研究可为区域草地退化对土壤水文生态效应影响提供科学依据。%The influences of grassland degradation on soil water retention were studied in the Jun- muchang region of Maqin County, where is in the source region of the Yellow River, and the grassland degradation in this area is very serious. The methods of quadrates comparing different grassland degradation degrees were chosen in this research. Some important conclusions were obtained from this study, which mainly contained four aspects as follows. 1 ) Capillary water capacity and saturated water content were the biggest in the nondegradated grassland with a soil depth of 0 - 10 cm but the smallest in the extremely degradated grassland. While the capillary water capacity and saturated water content had no significant differences for both cases in 10 -20 cm, and they were also the

  16. Reducing Nutrient Losses with Directed Fertilization of Degraded Soils

    Science.gov (United States)

    Menzies, E.; Walter, M. T.; Schneider, R.

    2016-12-01

    Degraded soils around the world are stunting agricultural productivity in places where people need it the most. In China, hundreds of years of agriculture and human activity have turned large swaths of productive grasslands into expanses of sandy soils where nothing can grow. Returning soils such as these to healthy productive landscapes is crucial to the livelihoods of rural families and to feeding the expanding population of China and the world at large. Buried wood chips can be used to improve the soils' water holding capacity but additional nutrient inputs are crucial to support plant growth and completely restore degraded soils in China and elsewhere. Improperly applied fertilizer can cause large fluxes of soluble nutrients such as nitrogen (N) and phosphorus (P) to pollute groundwater, and reach surface water bodies causing harmful algal blooms or eutrophication. Similarly, fertilization can create increases in nutrient losses in the form of greenhouse gases (GHGs). It is imperative that nutrient additions to this system be done in a way that fosters restoration and a return to productivity, but minimizes nutrient losses to adjacent surface water bodies and the atmosphere. The primary objective of this study is to characterize soluble and gaseous N and P losses from degraded sandy soils with wood chip and fertilizer amendments in order to identify optimal fertilization methods, frequencies, and quantities for soil restoration. A laboratory soil column study is currently underway to begin examining these questions results of this study will be presented at the Fall Meeting.

  17. Progress in sandy desertification research of China%中国沙漠化研究进展

    Institute of Scientific and Technical Information of China (English)

    王涛

    2004-01-01

    Sandy desertification is land degradation characterized by wind erosion mainly resulted from the excessive human activities in arid, semiarid and part of sub-humid regions in northern China. The research on sandy desertification has experienced more than 5 decades of arduous course of the struggle along with the establishment and development of China′s desert science. Researches in this field have made a great contribution to the national economic construction, and environmental protection. This paper focuses on presenting the major progress and achievements in the sandy desertification research during the last 50 years, including the stages of study on sandy desertification,background environment of sandy desertification and its changes, the conception, causes, process,monitoring and assessment of sandy desertification, the vegetation succession, landscape ecology, plant physiology, impacts on ecosystem, high-effective use of water and land resources and sustainable development in sandy desertified regions, sandy desertification control models and techniques etc.

  18. 近45年长江黄河源区高寒草地退化特征及成因分析%Rate and causes of degradation of alpine grassland in the source regions of the Yangtze and Yellow Rivers during the last 45 years

    Institute of Scientific and Technical Information of China (English)

    杜际增; 王根绪; 李元寿

    2015-01-01

    根据1969年航片数据、1986,2000,2007年以及2013年 TM 数据建立的长江黄河源区高寒草地生态系统空间数据集,结合该地区近50年的气候资料以及人类活动状况,分析了长江黄河源区高寒草地生态系统在全球变化背景下的变化趋势及其驱动因素。结果表明,近45年长江黄河源区高寒草地呈现以覆盖度降低、破碎化与干旱化加剧为主的退化趋势,长江黄河源区高寒草地退化的速率在20世纪80年代后期呈迅速增加趋势,2000年后退化速率逐渐降低;气温升高引起的区域的暖干化是导致长江黄河源区高寒草地生态系统退化格局形成的主要原因。过度放牧和人类不合理的开发是导致长江黄河源区高寒草地退化加剧的重要因素。%Alpine grassland is the main vegetation type in the source regions of the Yangtze and Yellow Rivers, and accounts for about 70% of the total area in this region.As a result,maintenance of ecosystem balance,wa-ter cycling and soil-atmosphere exchanges in these regions critically depends on the status of the local alpine grasslands.With current global changes such as climate change,and increased human population in the region, alpine grassland in this region has been subject to increasing grazing pressure with significant changes resul-ting.These environment and regional economic changes have attracted widespread attention.In this research, alpine grassland degradation in the source regions of Yangtze and Yellow Rivers was quantified by analysis of images obtained by aerial photography in 1969 and TM remote sensing data captured in 1989,2000,2007 and 2013.In addition,with the inclusion of climatic observation data and data on human factors,the causes of the degradation were analyzed by principal component analysis and the gray correlation method.The results show that the alpine grassland degradation is characterized by reducing coverage,and increasing fragmentation and

  19. Assessment of sandy desertification trends in the Shule River Basin from 1978 to 2010

    Institute of Scientific and Technical Information of China (English)

    Xiang Song; ChangZhen Yan; Sen Li; JiaLi Xie

    2014-01-01

    Sandy desertification in the Shule River Basin has expanded dramatically during the past 30 years. We evaluated the status, evolution, and main causes of sandy desertification by interpreting Landsat images which were acquired in 1978, 1990, 2000, 2005, and 2010, and analyzing the relevant meteorological data. The results show there was 3,477.95 km2, 3,733.32 km2, 3,620.29 km2, 3,565.65 km2, and 3,557.88 km2 of sandy desertified land in 1978, 1990, 2000, 2005, and 2010, respectively. From 1978 to 1990, not only the area of sandy desertified land (SDL) but also the degree of SDL levels increased. From 1990 to 2010 there was widespread restoration of SDL but the recovery trend of SDL gradually slowed. Although climate change contributes to expanding sandy desertification, human activities can either accelerate or reverse trends of natural sandy desertification. Some detrimental human activities can accelerate sandy desertification, but, conversely, desertification control measures such as the Three-North Shelter Forest Project and watershed rehabilitation programs in areas including the Shule River Basin resulted in many SDL being turned into grasslands or forest lands when shrubs and trees were planted to fix mobile sands at the edges of oases and cities. With population growth, much SDL has been reclaimed as farm land using water-saving agricultural methods or has been turned into built-up land as a result of urbanization.

  20. Impacts of Future Grassland Changes on Surface Climate in Mongolia

    Directory of Open Access Journals (Sweden)

    Fan Zhang

    2013-01-01

    Full Text Available Climate change caused by land use/cover change (LUCC is becoming a hot topic in current global change, especially the changes caused by the grassland degradation. In this paper, based on the baseline underlying surface data of 1993, the predicted underlying surface data which can be derived through overlaying the grassland degradation information to the map of baseline underlying surface, and the atmospheric forcing data of RCP 6.0 from CMIP5, climatological changes caused by future grassland changes for the years 2010–2020 and 2040–2050 with the Weather Research Forecast model (WRF are simulated. The model-based analysis shows that future grassland degradation will significantly result in regional climate change. The grassland degradation in future could lead to an increasing trend of temperature in most areas and corresponding change range of the annual average temperature of −0.1°C–0.4°C, and it will cause a decreasing trend of precipitation and corresponding change range of the annual average precipitation of 10 mm–50 mm. This study identifies lines of evidence for effects of future grassland degradation on regional climate in Mongolia which provides meaningful decision-making information for the development and strategy plan making in Mongolia.

  1. Spatial distribution of sandy desertificationchange in the west of Jilin Province

    Institute of Scientific and Technical Information of China (English)

    LIUHuiqing; XUJiawei; LVXinmiao

    2003-01-01

    The sandy land of the western part of Jilin Province is located in the ecotone of semi-humid and semi-arid area in the temperate zone of China. The sandy desertification has widely spread in the region because of the vulnerable natural conditions and the unreasonable human activity; as a result of this, the precious land resources and the economic development in the area have been seriously impacted. In this paper, the sandy land ecologic environment geographic information system is established based on the multi-spectral, multi-temporal Landsat TM images and field investigation. The comprehensive indexes of sandy desertification extent assessment which include vegetation degradation, wind erosion extent and soil depth are presented to classify the sandy land in western Jilin into three levels--slight, moderate and severe sandy desertification with the support of GIS platform. The results demonstrate that the sandy desertification has been partly controlled in the past twenty years, except some small sites. However, this doesn't necessarily mean that there is nothing for more concern. The two main causes of sandy desertification have not been eliminated yet, one is its natural factor, especially the physical and chemical characters of sandy soil and dry climate; another is the immoderate economic activity of human being that has highly accelerated the sandy desertification process.

  2. Effects of Government Grassland Conservation Policy on Household Livelihoods and Dependence on Local Grasslands: Evidence from Inner Mongolia, China

    Directory of Open Access Journals (Sweden)

    Bingzhen Du

    2016-12-01

    Full Text Available Grassland degradation intensifies human-environment conflicts and adversely affects local residents’ livelihoods. To reduce grassland degradation in Inner Mongolia, China, the government has enforced (since 1998 a series of grassland conservation and management policies that restrict the use of grasslands. To ease the impact on the residents’ livelihoods, the national and regional governments have offered a series of top-down arrangements to stimulate sustainable use of the grasslands. Simultaneously, local households spontaneously developed bottom-up countermeasures. To determine the effects of these processes, we interviewed members of 135 households using a mix of qualitative and quantitative methods. We analyzed the effects on household dependence on local grasslands and on perceptions of the future of grassland use. Our findings show that the implementation of the grassland conservation policies significantly affected household livelihoods, which in turn affected household use of natural assets (primarily the land, their agricultural assets (farming and grazing activities and their financial assets (income and consumption, resulting in fundamental transformation of their lifestyles. The households developed adaptation measures to account for the dependence of their livelihood on local ecosystems by initializing strategies, such as seeking off-farm work, leasing pasture land, increasing purchases of fodder for stall-fed animals and altering their diet and fuel consumption to compensate for their changing livelihoods.

  3. Reconciling scientific approaches for organic farming research. Part I. Reflection on research methods in organic grassland and animal production at the Louis Bolk Institute, The Netherlands. Part II. Effects of manure types and white clover (Trifolium repens) cultivars on the productivity of grass-clover mixtures on a humid sandy soil

    NARCIS (Netherlands)

    Baars, T.

    2002-01-01

    Part I : Reflection on research methods in organic grassland and animal production at the Louis Bolk Institute, The NetherlandsKey words: organic agriculture, anthroposophy, methodology, research strategy, experiential science, multidisciplinary science, Goethean scienceThis dissert

  4. Temperate grasslands as a dust source: Knowledge, uncertainties, and challenges

    Science.gov (United States)

    Shinoda, M.; Gillies, J. A.; Mikami, M.; Shao, Y.

    2011-12-01

    Temperate grasslands are sensitive to climate change and are significant, or potentially significant, dust sources. Temperate grassland aeolian processes are unique in that the vegetation growth-decay cycle and weathering process due to extreme temperature changes profoundly affect the occurrence and intensity of wind erosion and dust emission. Human activities, such as animal husbandry or cultivation, also may result in land degradation and enhanced wind erosion. So far, little systematic research on temperate grassland wind erosion has been done, but this issue deserves particular attention. In this review paper, we summarize the understanding of temperate grassland wind-erosion processes and identify the uncertainties and research needs. The needs include (1) a deeper understanding of the aerodynamic and physical controls of grassland vegetation on wind erosion and dust emission processes, (2) scaling known relationships upwards to model the regional scale, (3) quantifying critical parameters affecting dust emissions (i.e., surface and aerodynamic roughness) via remote-sensing techniques, and (4) integrated wind-erosion modeling that incorporates grassland aeolian database and vegetation modeling of both seasonal growth and decay plus the impacts of grazing and cultivation. We also outline the research being carried out by Japanese scientists in collaboration with colleagues at Mongolian, American, and German research institutes in developing a temperate grassland wind-erosion modeling system, which can be used as a pre-warning system of severe dust storms and as a tool for strategic management of temperate grasslands.

  5. Plant-conservative agriculture of acid and degraded Raña-grassland enhances diversity of the common soil mites (Oribatida)

    Energy Technology Data Exchange (ETDEWEB)

    Jorrín, J.; González-Fernández, P.

    2016-11-01

    The seminatural prairie of the Raña of Cañamero (Spain) is a degraded and unproductive agrosystem with acid and stony soils, and low coverage of xerophytic grasses. In a project about secondary reconversion of the raña-prairie to a more productive cropland, an experimental field (EF) was established to assess the effect on plot-productivity of the interaction between correction of soil pH (liming) with three cropping systems: a no-tilled and annually fertilized and improved prairies, and a conventionally-tilled forage crop. The EF model of management was designed as plant-conservative, because no herbicide was applied after seeding to preserve the post-emergence of wild herbs and the natural grass diversity of the prairie. Between 2008 and 2012, we analysed the effect of managing factors (initial conventional-tillage, fertilization, liming and cropping) and agricultural predictors (pH, C:N ratio, soil bulk density and herbaceous biomass) on the alpha(α)-diversity of one of the major group of soil animals, the oribatids. In relation to the raña-prairie, all EF-plots improved their soil bulk density (ρs) and herbaceous biomass (t/ha), and enhanced desirable α-diversity values (richness, abundance and community equity). We conclude that the plant-conservative model: i) do not affect statistically the species richness of the prairie; ii) the desirable α-diversity responses are negatively correlated with soil bulk density and positively with herbaceous biomass, and iii) the low input or minimum intervention model, of an initial and conventional till and annual fertilisation, is the threshold and optimal model of agricultural management to improving oribatids diversity of the raña-soil. (Author)

  6. Plant-conservative agriculture of acid and degraded Raña-grassland enhances diversity of the common soil mites (Oribatida

    Directory of Open Access Journals (Sweden)

    Juan Jorrín

    2016-03-01

    Full Text Available The seminatural prairie of the Raña of Cañamero (Spain is a degraded and unproductive agrosystem with acid and stony soils, and low coverage of xerophytic grasses. In a project about secondary reconversion of the raña-prairie to a more productive cropland, an experimental field (EF was established to assess the effect on plot-productivity of the interaction between correction of soil pH (liming with three cropping systems: a no-tilled and annually fertilized and improved prairies, and a conventionally-tilled forage crop. The EF model of management was designed as plant-conservative, because no herbicide was applied after seeding to preserve the post-emergence of wild herbs and the natural grass diversity of the prairie. Between 2008 and 2012, we analysed the effect of managing factors (initial conventional-tillage, fertilization, liming and cropping and agricultural predictors (pH, C:N ratio, soil bulk density and herbaceous biomass on the alpha(α-diversity of one of the major group of soil animals, the oribatids. In relation to the raña-prairie, all EF-plots improved their soil bulk density (ρs and herbaceous biomass (t/ha, and enhanced desirable α-diversity values (richness, abundance and community equity. We conclude that the plant-conservative model: i do not affect statistically the species richness of the prairie; ii the desirable α-diversity responses are negatively correlated with soil bulk density and positively with herbaceous biomass, and iii the low input or minimum intervention model, of an initial and conventional till and annual fertilisation, is the threshold and optimal model of agricultural management to improving oribatids diversity of the raña-soil.

  7. Fire Threatens the Grasslands

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    FIRE is herdsmen’s woe. It is said by elderly people that fire almost destroyed the entire grasslands long ago. Few domestic animals survived and with great difficulty the people rebuilt and replanted what they could for many generations. Because of their efforts the grasslands survived. I have never experienced that kind of tragedy, but I could sense the fear in people’s voices when they talked of it. It is actually an unwritten law on the grasslands that whenever a fire occurs, no matter how far away or how dangerous it is, you must go out and fight it.

  8. Grassland Management Plan [Draft

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This grassland management plan is for Bear River Migratory Bird Refuge in Utah. It includes a summary of the refuge, special considerations for endangered species,...

  9. Native grasslands fertilize themselves

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — News article about Lostwood National Wildlife Refuge and how the native soils and plants function to stimulate the system, creating a more productive grassland.

  10. Sandy PMO Disaster Relief Appropriations Act of 2013 Financial Data

    Data.gov (United States)

    Department of Homeland Security — Sandy PMO: Disaster Relief Appropriations Act of 2013 (Sandy Supplemental Bill) Financial Data. This is the Sandy Supplemental Quarterly Financial Datasets that are...

  11. Maize productivity and mineral N dynamics following different soil fertility management practices on a depleted sandy soil in Zimbabwe

    NARCIS (Netherlands)

    Chikowo, R.; Mapfumo, P.; Nyamugafata, P.; Giller, K.E.

    2004-01-01

    There is a need for an improved understanding of nitrogen (N) dynamics in depleted sandy soils in southern Africa. A field experiment was conducted to evaluate the performance of different soil fertility improvement practices on a degraded granitic sandy soil in Zimbabwe. Legumes capable of accumula

  12. Assessing the soil quality of alpine grasslands in the Qinghai-Tibetan Plateau using a modified soil quality index.

    Science.gov (United States)

    Li, Yuanyuan; Dong, Shikui; Wen, Lu; Wang, Xuexia; Wu, Yu

    2013-10-01

    Soil degradation has caused various problems on the planet. Human disturbance and land use changes always negatively affect soil quality. In this study, we used a modified soil quality index (SQI) to assess soil quality under differing degrees of human disturbance and land use. The alpine grasslands were studied at different levels of degradation [i.e., severely degraded grassland, heavily degraded grassland, moderately degraded grassland, and non-degraded grassland (NDG)] in a case study conducted in Qinghai-Tibetan Plateau (QTP) to test the feasibility of using the SQI. Fifteen chemical, physical, and biological soil parameters were measured in each type of grassland. Significant variations in SQI were found across the different types of grasslands according to severity of human disturbance and changes in land use. Urease, the ratio of microbial biomass nitrogen to total nitrogen, proteinase, and soil organic carbon were found to be the most important indicators for assessing soil quality. NDG had a higher SQI than the other three types of grasslands. It was concluded that SQI is effective for assessing the soil quality of alpine grasslands in the QTP. The intensity of human disturbance had a negative effect on soil quality in the QTP.

  13. Herdsmen's Perception of Grassland Degradation in the Source Region of the Yellow River: A Case Study in Dalag County%黄河源地区牧民对草地退化的感知——以达日县为例

    Institute of Scientific and Technical Information of China (English)

    张琴琴; 摆万奇; 张镱锂; 刘林山

    2011-01-01

    The source region of the Yellow River, located in the hinterland of the Qinghai-Tibet Plateau, is a typical ecological fragile area. Grassland rangeland degradation results primarily from climate change and human-induced activities. Moreover, the later would have a greater influence in some cases. Herdsmen are the main economic agent and basic unit of decision-making in this region, whose perception and adaptive strategy of grassland degradation are vital to sustainable development of grassland resources and pastoral areas. The authors chose Dalag County as a representative ecological fragile area in the source region of the Yellow River. Using the Participatory Rural Appraisal (PRA) method, the authors made an attempt to analyze herdsmen' s perception on climate change and grassland degradation so as to understand their attitudes and adaptive strategies to corresponding consequences. PRA aims to incorporate local knowledge and opinions by informal interviewing local people. During the PRA, the investigator and the respondent fully participate in processes including information collection, question identification and analysis, and decision-making. In this study, 143 households among seven towns were investigated in Dalag County. Quantitative methods were used to analyze inception, response, and adaptation of herdsmen to climate change and grassland degradation. Major findings are given as 1) herdsmen are sensitive to climate change, especially to extreme weather. Seasonal differences and abnormal climate change may bring a larger adverse influence to them. 2) Herdsmen are sensitive to grassland degradation. About 76.22% of herdsmen are aware of grassland degradation.However, they do not seem to understand the underlying mechanisms of grassland degradation. 3) Herdsmen have different perception to different control measures of grassland degradation. They tend to be in favor of measures increasing their benefits, such as pasture land construction and supplementary

  14. Hurricane Sandy Poster (October 29, 2012)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hurricane Sandy poster. Multi-spectral image from Suomi-NPP shows Hurricane Sandy approaching the New Jersey Coast on October 29, 2012. Poster size is approximately...

  15. Nitrate leaching from cut grassland as affected by the substitution of slurry with nitrogen mineral fertilizer on two soil types

    NARCIS (Netherlands)

    Schröder, J.J.; Assinck, F.B.T.; Uenk, D.; Velthof, G.L.

    2010-01-01

    A field experiment was conducted to find out whether there is any difference in risk of N leaching to groundwater when cattle slurry and/or mineral fertilizer-N was applied to cut grassland. The experiment was carried out over two consecutive years on two sites (one with a relatively wet sandy soil

  16. On Sandy Shores. Teacher's Guide.

    Science.gov (United States)

    Strang, Craig; And Others

    The activities in this guide (for grades 2-4) transport students to the sandy shore, one of the most fascinating ecosystems on the planet. At this ecological juncture a multiplicity of life forms find ways to survive, thrive, and interact with each other. Using a wide variety of learning formats, students explore and deepen their understanding of…

  17. Effect of Planting in Furrow and Whole Plastic-film Mulching on Double Ridges on Improving Degraded Desert Grassland%全膜双垄沟播技术改良荒漠化退化草原的研究

    Institute of Scientific and Technical Information of China (English)

    朱建宁; 彭文栋; 张秀红; 刘华; 高婷

    2012-01-01

    [ Objective] This study aimed to provide theoretical basis and technologies for the application of planting in furrow and whole plastic-film mulching on double ridges. [ Method] The conventional method was used to re-seed the bunch Gramineous forage in the degraded desert grassland in Yanchi, Ningxia Hui Autonomous Region. Four kinds of conservation treatments, namely, ridging with black film mulching, ridging with transparent film mulching, ridging with no mulching and the flatplanting with no ridging and mulching were conducted to the forage lo analyze the effects of each treatment on soil moisture and seedling growth. [ Result ] From July to November, the moisture contents of ridging with black film mulching, ridging with transparent film mulching, ridging with no mulching and the flalplanling were 9. 88% , 9. 24% , 8. 75% and 8. 13% , showing significant differences among the treatments; the survival rates of re-seeding forage were 96. 2% , 93.4% , 45.6% and 28. 3% , and the mulching treatment showed significant difference with the un-mulching treatments in survival rate. The treatment with black film mulching showed great advantage that its moisture content on ridge top had the buffering effect of "load shifting" , and the soil moisture content of black mulching treatment increased 21.5% than the flalplanting. Black film mulching also had the largest water supplement amount in soil below I m. Although mulching cost too much, its overall benefits were higher than that with no mulching. [ Conclusion ] This study lays the experimental basis for the application of planting in furrow and whole plastic-film mulching on double ridges in improving degraded grassland desertification.%[目的]探讨全膜双垄沟播技术改良荒漠化退化草原的效果,以期为扩大该技术的应用领域提供理论依据和技术贮备.[方法]在宁夏盐池荒漠化退化草原中采用常规方法补播丛生禾本科牧草,并对其进行起垄覆黑膜、起垄覆透明

  18. Study of spatial distribution of sandy desertification in North China in recent 10 years

    Institute of Scientific and Technical Information of China (English)

    WANG Tao; WU Wei; XUE Xian; SUN Qingwei; CHEN Guangting

    2004-01-01

    Sandy desertification is a land degradation characterized by wind erosion, mainly resulted from the excessive human activities in arid, semiarid and part of sub-humid regions in North China. It is one of main kinds of desertification/land degradation as well as water-soil erosion and salinization in China. Rapid and continuous spread of sandy desertification during last 50 years has created a major environmental and socio-economic problem in North China. Remote sensing monitored results in 2000 showed that the sandy desertified land area has been 38.57×104 km2. The area of potential to slightly sandy desertified land is 13.93×104 km2, moderately land 9.977×104 km2, severely land 7.909×104 km2 and very severely land 6.756×104km2. Sandy desertification mainly occurs in the semi-arid mixed farming-grazing zone and its northern rangeland zone, semi-arid dryland rainfed cropping zone and arid oasis-desert margin zone. The average annually developmental rate of sandy desertified land increased from 2,100tion in North China is "overall deterioration, while local rehabilitation". Already achieved rehabilitation results and monitoring assessment show that about 60% of desertified land in North China can be restored under the conditions of rational land-use ways and intensity.

  19. Grasslands Inspire Entrepreneur

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    THIRTY years ago, then 16-year-old Mu Cunyu left her family in Beijing to settle down on the grasslands ill Dongwuzhumuqin Banner of Xilingele League in the Inner Mongolia Autonomous Region. No one anticipated what the future would bring for this 1.55-meter tall girl. Thirty years later, she proved herself an outstanding entrepreneur managing more than 10 companies with total assets of 1 billion

  20. Carbon storage of Mediterranean grasslands

    OpenAIRE

    Corona, Piermaria; Badalamenti, Emilio; Pasta, Salvatore; La Mantia, Tommaso

    2016-01-01

    Secondary grasslands are one of the most common vegetation types worldwide. In Europe, and in the Mediterranean basin, human activities have transformed many woodlands into secondary grasslands. Despite their recognized role in the global carbon cycle, very few data are available for estimating the biomass of Mediterranean grasslands. We developed linear regression models in order to predict the biomass of two native Mediterranean grasses (Ampelodesmos mauritanicus and Hyparrhenia hirta) and ...

  1. Holocene grassland vegetation, climate and human impact in central eastern Inner Mongolia

    Institute of Scientific and Technical Information of China (English)

    HUANG; Fei; Kealhofer; Lisa; XIONG; Shangfa; HUANG; Fengb

    2005-01-01

    Phytolith and pollen preserved in the Taipusi Banner paleosol profile, central eastern Inner Mongolia, provide evidence of Holocene grassland vegetation, climate and human impact. The combined phytolith and pollen records reveal a major change in vegetation composition about 5000 a BP. Before 5000 a BP, the vegetation was dominated by Aneurolepidium chinese-Stipa grandis grassland of C4 grasses. After 5000 a BP, C4 grasses rapidly retreated,indicating a shift to colder and more arid conditions. The gradual invasion of Stipa krylovii, Agropyron desertorum, Ephedra, Chenopodiaceae and Caragana reveal the onset of grassland degeneration. Between 10000 and 8720 a BP, the Aneurolepidium chinese-Stipa grandis grassland included a small proportion of Artemisia shrub and Echionopos type plants, implying a strong winter monsoon and very weak summer monsoon. From 8720 to 7000 a BP, C4 grasses were common, indicating a strengthening of the summer monsoon. Between 7000 and 5000 a BP,the Holocene thermal maximum was evident, with a significant expansion of C4 grasses and the presence of some trees (such as Pinus and Betula, and so on) in or near the study site. From 4200-3000 a BP, a sandy grassland of Artemisia and Agropyron desertorum together with As ter-type taxa occurred. Precipitation amelioration took place between 3000 and 2170 a BP, with a rapid development of Echinops type plants and a small expansion of C4 grasses. From 2170 a BP to present, human activities accelerated the process of grassland degeneration.

  2. DYNAMICS OF SANDY DESERTIFICATION AND ITS DRIVING FORCES IN WESTERN JILIN PROVINCE

    Institute of Scientific and Technical Information of China (English)

    LI Fang; HE Yan-fen; LIU Zhi-ming; ZHANG Bai

    2004-01-01

    By establishing the interpreting elements, and applying supervised classification, the sandy desertification was interpreted and the desertified land areas of the counties in the western Jilin Province in 1986 and in 2000 were obtained. Taking Tongyu and Qian'an as examples, the natural driving forces and man-made driving forces were analyzed. The paper comes the conclusions that the material sources and the warming and dry climate are the internal causes of potential land desertification; the irrational human activities, such as destroying forest and reclaiming the grassland, are the external causes of potential land desertification; while more rational human activities, such as planting trees and restoring grassland can reverse the land desertification. Furthermore, the countermeasures and suggestions for the development of agriculture and animal husbandry in the western Jilin Province are put forward.

  3. [Vegetation index estimation by chlorophyll content of grassland based on spectral analysis].

    Science.gov (United States)

    Xiao, Han; Chen, Xiu-Wan; Yang, Zhen-Yu; Li, Huai-Yu; Zhu, Han

    2014-11-01

    Comparing the methods of existing remote sensing research on the estimation of chlorophyll content, the present paper confirms that the vegetation index is one of the most practical and popular research methods. In recent years, the increasingly serious problem of grassland degradation. This paper, firstly, analyzes the measured reflectance spectral curve and its first derivative curve in the grasslands of Songpan, Sichuan and Gongger, Inner Mongolia, conducts correlation analysis between these two spectral curves and chlorophyll content, and finds out the regulation between REP (red edge position) and grassland chlorophyll content, that is, the higher the chlorophyll content is, the higher the REIP (red-edge inflection point) value would be. Then, this paper constructs GCI (grassland chlorophyll index) and selects the most suitable band for retrieval. Finally, this paper calculates the GCI by the use of satellite hyperspectral image, conducts the verification and accuracy analysis of the calculation results compared with chlorophyll content data collected from field of twice experiments. The result shows that for grassland chlorophyll content, GCI has stronger sensitivity than other indices of chlorophyll, and has higher estimation accuracy. GCI is the first proposed to estimate the grassland chlorophyll content, and has wide application potential for the remote sensing retrieval of grassland chlorophyll content. In addition, the grassland chlorophyll content estimation method based on remote sensing retrieval in this paper provides new research ideas for other vegetation biochemical parameters' estimation, vegetation growth status' evaluation and grassland ecological environment change's monitoring.

  4. Understanding of Grassland Ecosystems under Climate Change and Economic Development Pressures in the Mongolia Plateau

    Science.gov (United States)

    Qi, J.; Chen, J.; Shan, P.; Pan, X.; Wei, Y.; Wang, M.; Xin, X.

    2011-12-01

    The land use and land cover change, especially in the form of grassland degradation, in the Mongolian Plateau, exhibited a unique spatio-temporal pattern that is a characteristic of a mixed stress from economic development and climate change of the region. The social dimension of the region played a key role in shaping the landscape and land use change, including the cultural clashes with economic development, conflicts between indigenous people and business ventures, and exogenous international influences. Various research projects have been conducted in the region to focus on physical degradation of grasslands and/or on economic development but there is a lack of understanding how the social and economic dimensions interact with grassland ecosystems and changes. In this talk, a synthesis report was made based on the most recent workshop held in Hohhot, Inner Mongolia, of China, that specifically focused on climate change and grassland ecosystems. The report analyzed the degree of grassland degradation, its climate and social drivers, and coupling nature of economic development and conservation of traditional grassland values. The goal is to fully understand the socio-ecological-economic interactions that together shape the trajectory of the grassland ecosystems in the Mongolia Plateau.

  5. Application of satellite remote sensing for mapping wind erosion risk and dusk emission-deposition in Inner Mongolia grassland, China

    NARCIS (Netherlands)

    Reiche, M.; Funk, R.; Zhang, Z.; Hoffmann, C.; Reiche, J.; Wehrhan, M.; Li, Y.; Sommer, M.

    2012-01-01

    Intensive grazing leads to land degradation and desertification of grassland ecosystems followed by serious environmental and social problems. The Xilingol steppe grassland in Inner Mongolia, China, which has been a sink area for dust for centuries, is strongly affected by the negative effects of ov

  6. Landscape Change and Sandy Desertification Monitoring and Assessment

    Directory of Open Access Journals (Sweden)

    Eltahir M. Elhadi

    2009-01-01

    Full Text Available Problem statement: The objective of this study is to develop techniques for assessing and analyzing sand desertification in the northern part of Shaanxi Province, China. Approach: In order to reveal the process of land degradation, especially the latest situation of sandy desertification, a method integrating remote sensing, Geographic Information System (GIS and field survey was employed to build a sandy desertification dataset for analysis. Remote Sensing images included the Landsat Thematic Mapper (TM images in 1987 and Landsat Enhanced Thematic Mapper Plus (ETM+ images in 1999. Eight land-cover classes, including active sand dunes, fixed sand dunes, semi-fixed sand dunes, grass land, farm land, wet land, built up area and unused land and Normalized Difference Vegetation Index (NDVI, were identified. Results: The results showed that the active sand dunes and semi-fixed sand dunes have increased with a change rate of 128.70 and 55.65 km2 year-1, respectively, in the meantime the fixed sand dunes has decreased with a decreasing rate of 182.14 km2 year-1. During the 1987s, the area of sandy desertified land reached 12,006.11 km2 (57.17% of the total sandy area, of which severely desertified, medium desertified and slightly desertified land areas were 4,442.23, 4,253.45 and 3,310.43 km2, respectively. By the year 1999, the area of desertified land was increased to 13,782.30 km2 (65.63% of the total sandy area, of which severely desertified, medium desertified and slightly desertified land areas were 5,169.89, 4,918.15 and 3,694.26 km2, respectively increasing by 1,776.19 km2. Conclusion: Spatial change detection based on active sand dunes showed that the expansion area was much larger than the reversion in the past two decades and that several active sand belts has been formed, suggesting that sandy desertification of northern part of Shaanxi Province, China, will be a long-term task.

  7. Grassland responses to precipitation extremes

    Science.gov (United States)

    Grassland ecosystems are naturally subjected to periods of prolonged drought and sequences of wet years. Climate change is expected to enhance the magnitude and frequency of extreme events at the intraannual and multiyear scales. Are grassland responses to extreme precipitation simply a response to ...

  8. Measured and Estimated Volatilisation of Naphthalene from a Sandy Soil

    DEFF Research Database (Denmark)

    Lindhardt, Bo; Christensen, Thomas Højlund

    1994-01-01

    The non-steady-state fluxes of naphthalene from an artificially contaminated sandy soil at different water contents were measured in the laboratory, at 10°C. The soil contained 1.1% of organic carbon and the water content varied between 2.8 and 14% w/w. The diffusive flux of naphthalene from the ...... the fluxes by a factor of 1.5 to 6.4. The largest deviation between predicted and observed dynamic fluxes was found at high water contents. For the cover soil, half-life times of 1 to 2 days were estimated by the model for naphthalene degradation....

  9. Exotic flora of some grasslands of Nilgiris with their medicinal uses.

    Science.gov (United States)

    Paulsamy, S; Suresh, D

    2007-07-01

    In addition to the dominance of indigenous plant species, the grasslands of Nilgiris harbour a considerable number of exotic plants with sizeable number of individuals. In the present study in four major grasslands of Nilgiris, out of 12 exotic species present, 10 are recognized as medicinally important. The family, Asteraceae contributed a higher number of 6 medicinal species to the grassland community. The density of exotics in the studied grasslands is varied between 4 and 66/ha. In order to conserve the native species, the frequent harvesting of useful parts of exotics is suggested. In addition cultivation of these exotics in the degraded grasslands and other suitable habitats in Nilgiris may also reduce the pressure upon the native species and at the same time it will also meet the demand.

  10. Habitat availability is a more plausible explanation than insecticide acute toxicity for U.S. grassland bird species declines

    Science.gov (United States)

    Grassland bird species have experienced substantial declines in North America. These declines have been largely attributed to habitat loss and degradation, especially from agricultural practices and intensification (the habitat-availability hypothesis). A recent analysis of North American Breeding B...

  11. Preliminary reconstruction of the desert and sandy land distributions in China since the last interglacial period

    Institute of Scientific and Technical Information of China (English)

    CHEN; Huizhong; SU; Zhizhu; YANG; Ping; DONG; Guangrong

    2004-01-01

    The desert and sandy land are the products of arid climate. The spatial distribution of modern deserts and sandy land in China and their relation to climate show following characteristics: arid and hyper-arid desert zones, at isohyet of less than 200 mm, are dominated by mobile dunes; semi-arid steppe and arid desert steppe with the precipitation between 200-400mm, are dominated by semi-fixed and fixed sand dunes; the precipitation of sub-humid forest grassland and humid forest zones with scattered fixed sand land is higher than 400 mm. With this as reference, in combination with considerable amount of paleoclimatic data in desert regions and adjacent regions, the distributions of desert and sandy land in China during the last interglacial period, the last glacial maximum (LGM), and the Holocene megathermal, were preliminarily reconstructed. The results compared with that of today show that the distribution of desert and sandy land in China was greatly dwindled during last interglacial period, and the mobile dune area was about two-thirds of that of today's, but greatly expanded during LGM. However, the dwindling area of desert and sandy land in the Holocene megathermal was smaller than that in the last interglacial period. The forcing mechanism was mainly related to the changes of East Asian winter and summer monsoon, south-northward swing of the westerlies and the variations of the Qinghai-Tibet Plateau monsoon intensity caused by global climate changes during the cold and warm intervals since the last interglacial period.

  12. IMPLEMENTASI SANDI HILL UNTUK PENYANDIAN CITRA

    Directory of Open Access Journals (Sweden)

    JJ Siang

    2002-01-01

    Full Text Available Hill's code is one of text encoding technique. In this research, Hill's code is extended to image encoding. The image used is BMP 24 bit format. 2x2 and 3x3 matrices is used as a key. The results show that Hill's code is suitable for image whose RGB values vary highly. On the contrary, it is not suitable for less varied RGB images since its original pattern is still persisted in encrypted image. Hill's code for image encoding has also disadvantage in the case that the key matrix is not unique. However, for daily application, with good key matrix, Hill's code can be applied to encode image since it's process only deals with simple matrix operation so it become fast. Abstract in Bahasa Indonesia : Sandi Hill merupakan salah satu teknik penyandian teks. Dalam penelitian ini, pemakaian sandi Hill diperluas dari teks ke citra bertipe BMP 24 bit. Matriks yang dipakai berordo 2x2 dan 3x3. Hasil percobaan menunjukkan bahwa sandi Hill cocok untuk enkripsi citra dengan variasi nilai RGB antar piksel berdekatan yang tinggi (seperti foto, tapi tidak cocok untuk citra dengan variasi nilai RGB yang rendah (seperti gambar kartun karena pola citra asli masih tampak dalam citra sandi. Sandi Hill juga memiliki kelemahan dalam hal tidak tunggalnya matriks kunci yang dapat dipakai. Akan tetapi untuk pemakaian biasa, dengan pemilihan matriks kunci yang baik, sandi Hill dapat dipakai untuk penyandian karena hanya melibatkan operasi matriks biasa sehingga prosesnya relatif cepat. Kata kunci: Sandi Hill, Citra, Relatif Prima.

  13. EAARL Coastal Topography-Sandy Hook 2007

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A first surface/bare earth elevation map (also known as a Digital Elevation Model, or DEM) of the Gateway National Recreation Area's Sandy Hook Unit in New Jersey...

  14. Heterotrophic bacterial populations in tropical sandy beaches

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, S.; LokaBharathi, P.A.

    Distribution pattern of heterotrophic bacterial flora of three sandy beaches of the west coast of India was studied. The population in these beaches was microbiologically different. Population peaks of halotolerant and limnotolerant forms were...

  15. Importance and Functions of Grasslands

    Directory of Open Access Journals (Sweden)

    Lucien CARLIER

    2009-06-01

    Full Text Available Grasslands, mixture of grass, clover and other leguminous species, dicotyledonous, herbs and shrubs, contribute to a high degree to the struggle against erosion and to the regularizing of water regimes, to the purification of fertilizers and pesticides and to biodiversity and they have aesthetic role and recreational function as far as they provide public access that other agricultural uses do not allow. Grassland will continue to be an important form of land use in Europe, but with increased diversity in management objectives and systems used. Besides its role as basic nutrient for herbivores and ruminants, grasslands have opportunities for an adding value by exploiting positive health characteristics in animal products from grassland and through the delivery of environmental benefits. But even for grassland it is very difficult to create a good frame for its different tasks (1 the provision of forage for livestock, (2 protection and conservation of soil and water resources, (3 furnishing a habitat for wildlife, both flora and fauna and (4 contribution to the attractiveness of the landscape. Nevertheless it is the only crop able to fulfil so many tasks and to fit so many requirements. In this article the focus is limited to the grass and clover components of the grasslands.

  16. Modeling effects of conservation grassland losses on amphibian habitat

    Science.gov (United States)

    Mushet, David M.; Neau, Jordan L.; Euliss, Ned H.

    2014-01-01

    Amphibians provide many ecosystem services valued by society. However, populations have declined globally with most declines linked to habitat change. Wetlands and surrounding terrestrial grasslands form habitat for amphibians in the North American Prairie Pothole Region (PPR). Wetland drainage and grassland conversion have destroyed or degraded much amphibian habitat in the PPR. However, conservation grasslands can provide alternate habitat. In the United States, the Conservation Reserve Program (CRP) is the largest program maintaining grasslands on agricultural lands. We used an ecosystem services model (InVEST) parameterized for the PPR to quantify amphibian habitat over a six-year period (2007–2012). We then quantified changes in availability of amphibian habitat under various land-cover scenarios representing incremental losses (10%, 25%, 50%, 75%, and 100%) of CRP grasslands from 2012 levels. The area of optimal amphibian habitat in the four PPR ecoregions modeled (i.e., Northern Glaciated Plains, Northwestern Glaciated Plains, Lake Agassiz Plain, Des Moines Lobe) declined by approximately 22%, from 3.8 million ha in 2007 to 2.9 million ha in 2012. These losses were driven by the conversion of CRP grasslands to croplands, primarily for corn and soybean production. Our modeling identified an additional 0.8 million ha (26%) of optimal amphibian habitat that would be lost if remaining CRP lands are returned to crop production. An economic climate favoring commodity production over conservation has resulted in substantial losses of amphibian habitat across the PPR that will likely continue into the future. Other regions of the world face similar challenges to maintaining amphibian habitats.

  17. Phosphorus fractions in sandy soils of vineyards in southern Brazil

    Directory of Open Access Journals (Sweden)

    Djalma Eugênio Schmitt

    2013-04-01

    Full Text Available Phosphorus (P applications to vineyards can cause P accumulation in the soil and maximize pollution risks. This study was carried out to quantify the accumulation of P fractions in sandy soils of vineyards in southern Brazil. Soil samples (layers 0-5, 6-10 and 11-20 cm were collected from a native grassland area and two vineyards, after 14 years (vineyard 1 and 30 years (vineyard 2 of cultivation, in Santana do Livramento, southern Brazil, and subjected to chemical fractionation of P. Phosphorus application, especially to the 30-year-old vineyard 2, increased the inorganic P content down to a depth of 20 cm, mainly in the labile fractions extracted by anion-exchange resin and NaHCO3, in the moderately labile fraction extracted by 0.1 and 0.5 mol L-1 NaOH, and in the non-labile fraction extracted by 1 mol L-1 HCl, indicating the possibility of water eutrophication. Phosphorus application and grapevine cultivation time increased the P content in the organic fraction extracted by NaHCO3 from the 0-5 cm layer, and especially in the moderately labile fraction extracted by 0.1 mol L-1 NaOH, down to a depth of 20 cm.

  18. Enhanced degradation of mono aromatic hydrocarbons in sandy aquifer materials

    Energy Technology Data Exchange (ETDEWEB)

    Corseuil, Henry X. [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Engenharia Sanitaria; Weber Junior, W.J. [Michigan Univ., Ann Arbor, MI (United States). Dept. of Civil and Environmental Engineering

    1993-12-31

    The use of an inoculation technique to enhance rates of in-situ biodegradation of toxic organic contaminants by increasing subsurface populations of specific microorganisms is described. An external biologically active carbon (BAC) adsorber is demonstrated to be an efficient reactor system for collection, acclimation and enrichment of microorganisms for the inoculation process (author). 15 refs., 3 figs.

  19. Fire impacts on water repellency of sandy soils in SW Spanish coast

    Science.gov (United States)

    Jordán, Antonio; Zavala, Lorena M.; Gordillo-Rivero, Ángel J.; Muñoz-Rojas, Miriam; Keesstra, Saskia; Cerdá, Artemi

    2017-04-01

    Although water repellency of sandy soils from dune areas and their consequences (irregular wetting front, preferential flow pathways) are well studied, there is not much information about the effect of fire on hydrophobicity and its consequences in these areas. In this paper we study the in-depth variation of water repellency of burnt sandy soils from south-western Spain. Generally, it was observed that water repellency from unburnt forest soils is relatively higher than in shrublands and grasslands (where the lowest values were observed). However, the impact of fire caused a strong increase of hydrophobicity in the first two cases, with no major differences between them. This study confirms the presence of natural water repellency in sandy soils, as well as some of its consequences (irregular infiltration or increased surface water flow) depending on the type of vegetation, although the differences observed in burnt soils suggest that, although the composition of vegetation is important in the formation of natural water repellency, organic matter content is much more important in the case of burnt soils.

  20. 吉林省西部土地沙化动态变化%Spatial distribution of sandy desertification change in the west of Jilin Province

    Institute of Scientific and Technical Information of China (English)

    刘惠清; 许嘉巍; 吕新苗

    2003-01-01

    The sandy land of the western part of Jilin Province is located in the ecotone ofsemi-humid and semi-arid area in the temperate zone of China. The sandy desertification has widelyspread in the region because of the vulnerable natural conditions and the unreasonable humanactivity; as a result of this, the precious land resources and the economic development in the areahave been seriously impacted. In this paper, the sandy land ecologic environment geographicinformation system is established based on the multi-spectral, multi-temporal Landsat TM images andfield investigation. The comprehensive indexes of sandy desertification extent assessment whichinclude vegetation degradation, wind erosion extent and soil depth are presented to classify the sandyland in western Jilin into three levels--slight, moderate and severe sandy desertification with thesupport of GIS platform. The results demonstrate that the sandy desertiffcation has been partlycontrolled in the past twenty years, except some small sites. However, this doesn't necessarily meanthat there is nothing for more concern. The two main causes of sandy desertification have not beeneliminated yet, one is its natural factor, especially the physical and chemical characters of sandy soiland dry climate; another is the immoderate economic activity of human being that has highlyaccelerated the sandy desertification process.

  1. Grass Cover Influences Hydrophysical Parameters and Heterogeneity of Water Flow in a Sandy Soil

    Institute of Scientific and Technical Information of China (English)

    L. LICHNER; D. J. ELDRIDGE; K. SCHACHT; N. ZHUKOVA; L. HOLKO; M. (S)(I)R; J. PECHO

    2011-01-01

    Vegetation cover has a major effect on water flow in soils.Two sites,separated by distance of about 50 m,were selected to quantify the influence of grass cover on hydrophysical parameters and heterogeneity of water flow in a sandy soil emerging during a heavy rain following a long hot,dry period.A control soil (pure sand) with limited impact of vegetation or organic matter was obtained by sampling at 50 cm depth beneath a glade area,and a grassland soil was covered in a 10 cm thick humic layer and colonised by grasses.The persistence of water repellency was measured using the water drop penetration time test,sorptivity and unsaturated hydraulic conductivity using a mini disk infiltrometer,and saturated hydraulic conductivity using a double-ring infiltrometer.Dye tracer experiments were used to assess the heterogeneity of water flow,and both the modified method for estimating effective cross section and an original method for assessing the degree of preferential flow were used to quantify this heterogeneity from the images of dyed soil profiles.Most hydrophysical parameters were substantially different between the two surfaces.The grassland soil had an index of water repellency about 10 times that of pure sand and the persistence of water repellency almost 350 times that of pure sand.Water and ethanol sorptivities in the grassland soil were 7% and 43%,respectively,of those of the pure sand.Hydraulic conductivity and saturated hydraulic conductivities in the grassland soil were 5% and 16% of those of the pure sand,respectively.Dye tracer experiments revealed a stable flow with "air-draining" condition in pure sand and well-developed preferential flow in grassland soil,corresponding to individual grass tussocks and small micro-depressions.The grassland soil was substantially more water repellent and had 3 times the degree of preferential flow compared to pure sand.The results of this study reinforce our view that the consequences of any change in climate

  2. Sediment Chemistry and Toxicity in Barnegat Bay, New Jersey: Pre- and Post- Hurricane Sandy, 2012-2013.

    Science.gov (United States)

    Romanok, Kristin; Szabo, Zoltan; Reilly, Timothy J.; Defne, Zafer; Ganju, Neil K.

    2016-01-01

    Hurricane Sandy made landfall in Barnegat Bay, October, 29, 2012, damaging shorelines and infrastructure. Estuarine sediment chemistry and toxicity were investigated before and after to evaluate potential environmental health impacts and to establish post-event baseline sediment-quality conditions. Trace element concentrations increased throughout Barnegat Bay up to two orders of magnitude, especially north of Barnegat Inlet, consistent with northward redistribution of silt. Loss of organic compounds, clay, and organic carbon is consistent with sediment winnowing and transport through the inlets and sediment transport modeling results. The number of sites exceeding sediment quality guidance levels for trace elements tripled post-Sandy. Sediment toxicity post-Sandy was mostly unaffected relative to pre-Sandy conditions, but at the site with the greatest relative increase for trace elements, survival rate of the test amphipod decreased (indicating degradation). This study would not have been possible without comprehensive baseline data enabling the evaluation of storm-derived changes in sediment quality.

  3. Sediment chemistry and toxicity in Barnegat Bay, New Jersey: Pre- and post-Hurricane Sandy, 2012-13.

    Science.gov (United States)

    Romanok, Kristin M; Szabo, Zoltan; Reilly, Timothy J; Defne, Zafer; Ganju, Neil K

    2016-06-30

    Hurricane Sandy made landfall in Barnegat Bay, October, 29, 2012, damaging shorelines and infrastructure. Estuarine sediment chemistry and toxicity were investigated before and after to evaluate potential environmental health impacts and to establish post-event baseline sediment-quality conditions. Trace element concentrations increased throughout Barnegat Bay up to two orders of magnitude, especially north of Barnegat Inlet, consistent with northward redistribution of silt. Loss of organic compounds, clay, and organic carbon is consistent with sediment winnowing and transport through the inlets and sediment transport modeling results. The number of sites exceeding sediment quality guidance levels for trace elements tripled post-Sandy. Sediment toxicity post-Sandy was mostly unaffected relative to pre-Sandy conditions, but at the site with the greatest relative increase for trace elements, survival rate of the test amphipod decreased (indicating degradation). This study would not have been possible without comprehensive baseline data enabling the evaluation of storm-derived changes in sediment quality.

  4. Nonlinearly combined impacts of initial perturbation from human activities and parameter perturbation from climate change on the grassland ecosystem

    Directory of Open Access Journals (Sweden)

    G. Sun

    2011-11-01

    Full Text Available Human activities and climate change are important factors that affect grassland ecosystems. A new optimization approach, the approach of conditional nonlinear optimal perturbation (CNOP related to initial and parameter perturbations, is employed to explore the nonlinearly combined impacts of human activities and climate change on a grassland ecosystem using a theoretical grassland model. In our study, it is assumed that the initial perturbations and parameter perturbations are regarded as human activities and climate change, respectively. Numerical results indicate that the climate changes causing the maximum effect in the grassland ecosystem are different under disparate intensities of human activities. This implies the pattern of climate change is very critical to the maintenance or degradation of grassland ecosystem in light of high intensity of human activities and that the grassland ecosystem should be rationally managed when the moisture index decreases. The grassland ecosystem influenced by the nonlinear combination of human activities and climate change undergoes abrupt change, while the grassland ecosystem affected by other types of human activities and climate change fails to show the abrupt change under a certain range of perturbations with the theoretical model. The further numerical analyses also indicate that the growth of living biomass and the evaporation from soil surface shaded by the wilted biomass may be crucial factors contributing to the abrupt change of the grassland equilibrium state within the theoretical model.

  5. Feedbacks between woody plant encroachment and microclimate in desert grasslands

    Science.gov (United States)

    D'Odorico, P.; He, Y.; De Wekker, S.; Fuentes, J. D.; Collins, S. L.; Pockman, W.

    2011-12-01

    The encroachment of woody plants into grasslands is a global phenomenon that results from a variety of drivers related to land use and global environmental change. In the southwestern U.S., shrub encroachment can be associated with land degradation, soil erosion, and the formation of coppice dunes. In this region, the relatively abrupt character of grassland-to-shrubland transitions - both in time and in space - suggests that arid and semiarid rangelands may exhibit two alternative stable states characterized by either grass or shrub dominance. In these bistable landscapes, even small changes in environmental drivers may cause abrupt state transitions from grassland to shrubland, sustained by positive feedbacks with environmental drivers. We show that positive feedbacks between land cover change and microclimate may contribute to shrub encroachment in the southwestern US. Thus, we investigate changes in surface air temperature and energy balance resulting from grass-to-shrub transitions in the northern Chiuhuahuan desert. We find that the encroachment of native shrubs into desert grasslands modifies the surface energy balance with the overall net effect of increasing nighttime air temperatures, thereby favoring the establishment and growth of freeze-sensitive Larrea plants.

  6. Evaluation of SPOT imagery for the estimation of grassland biomass

    Science.gov (United States)

    Dusseux, P.; Hubert-Moy, L.; Corpetti, T.; Vertès, F.

    2015-06-01

    In many regions, a decrease in grasslands and change in their management, which are associated with agricultural intensification, have been observed in the last half-century. Such changes in agricultural practices have caused negative environmental effects that include water pollution, soil degradation and biodiversity loss. Moreover, climate-driven changes in grassland productivity could have serious consequences for the profitability of agriculture. The aim of this study was to assess the ability of remotely sensed data with high spatial resolution to estimate grassland biomass in agricultural areas. A vegetation index, namely the Normalized Difference Vegetation Index (NDVI), and two biophysical variables, the Leaf Area Index (LAI) and the fraction of Vegetation Cover (fCOVER) were computed using five SPOT images acquired during the growing season. In parallel, ground-based information on grassland growth was collected to calculate biomass values. The analysis of the relationship between the variables derived from the remotely sensed data and the biomass observed in the field shows that LAI outperforms NDVI and fCOVER to estimate biomass (R2 values of 0.68 against 0.30 and 0.50, respectively). The squared Pearson correlation coefficient between observed and estimated biomass using LAI derived from SPOT images reached 0.73. Biomass maps generated from remotely sensed data were then used to estimate grass reserves at the farm scale in the perspective of operational monitoring and forecasting.

  7. Birds of Southwestern grasslands: Status, conservation, and management

    Science.gov (United States)

    Michele Merola-Zwartjes

    2005-01-01

    In the Southwestern United States, the grassland avifauna is collectively composed of a mixture of species found primarily in desert grasslands, shortgrass steppe, wet meadows, and alpine tundra (as used here, desert grasslands incorporate both arid grasslands and desert shrub grasslands). Of these habitats, desert grasslands and shortgrass steppe are the most...

  8. Habitat availability is a more plausible explanation than insecticide acute toxicity for U.S. grassland bird species declines.

    Science.gov (United States)

    Hill, Jason M; Egan, J Franklin; Stauffer, Glenn E; Diefenbach, Duane R

    2014-01-01

    Grassland bird species have experienced substantial declines in North America. These declines have been largely attributed to habitat loss and degradation, especially from agricultural practices and intensification (the habitat-availability hypothesis). A recent analysis of North American Breeding Bird Survey (BBS) "grassland breeding" bird trends reported the surprising conclusion that insecticide acute toxicity was a better correlate of grassland bird declines in North America from 1980-2003 (the insecticide-acute-toxicity hypothesis) than was habitat loss through agricultural intensification. In this paper we reached the opposite conclusion. We used an alternative statistical approach with additional habitat covariates to analyze the same grassland bird trends over the same time frame. Grassland bird trends were positively associated with increases in area of Conservation Reserve Program (CRP) lands and cropland used as pasture, whereas the effect of insecticide acute toxicity on bird trends was uncertain. Our models suggested that acute insecticide risk potentially has a detrimental effect on grassland bird trends, but models representing the habitat-availability hypothesis were 1.3-21.0 times better supported than models representing the insecticide-acute-toxicity hypothesis. Based on point estimates of effect sizes, CRP area and agricultural intensification had approximately 3.6 and 1.6 times more effect on grassland bird trends than lethal insecticide risk, respectively. Our findings suggest that preserving remaining grasslands is crucial to conserving grassland bird populations. The amount of grassland that has been lost in North America since 1980 is well documented, continuing, and staggering whereas insecticide use greatly declined prior to the 1990s. Grassland birds will likely benefit from the de-intensification of agricultural practices and the interspersion of pastures, Conservation Reserve Program lands, rangelands and other grassland habitats into

  9. Grassland Management Plan : Trempealeau National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Trempealeau National Wildlife Refuge Grassland Management Plan provides guidelines for grassland habitat preservation and management. The goals of this plan aim...

  10. Penetration grouting reinforcement of sandy gravel

    Institute of Scientific and Technical Information of China (English)

    YANG Ping; PENG Zhen-bin; TANG Yi-qun; PENG Wen-xiang; HE Zhong-ming

    2008-01-01

    To study the relationship between grouting effect and grouting factors, three factors (seven parameters) directionless pressure and small cycle grouting model experiment on sandy gravel was done, which was designed according to uniform design method. And regressing was applied to analysis of the test data. The two models test results indicate that when the diffusing radius of grout changes from 26 to 51 era, the grouted sandy gravel compressing strength changes fTom 2.13 to 12.30 MPa; the relationship between diffusing radius(R) and water cement ratio(m), permeability coefficient(k), grouting pressure(p), grouting time(t) is R=19.953m0.121k0.429p0.412t0.437, the relationship between compressing strength(P) and porosity(n), water cement ratio, grouting pressure, grouting time is P=0.984n0.517m-1.488p0.118t0.031.So the porosity of sandy gravel, the permeability coefficient of sandy gravel, grouting pressure, grouting time, water cement ratio are main factors to influence the grouting effect. The grouting pressure is the main factor to influence grouting diffusing radius, and the water cement ratio is the main factor to influence grouted sandy gravel compressing strength.

  11. The bioremediation potential of marine sandy sediment microbiota

    Directory of Open Access Journals (Sweden)

    Dan Răzvan POPOVICIU

    2012-11-01

    Full Text Available The natural microbiota from marine sandy sediments on the Romanian sea coast was tested for resilience in case of hydrocarbon contamination, for estimating the number of (culturable hydrocarbon and lipid oil-degrading microorganisms and for determining the influence of inorganic nitrate and phosphate nutrients on hydrocarbon spill bioremediation process, by microcosm experiments.Results show that hydrocarbon contamination affects the bacteriobenthos both in terms of cell numbers and composition. Bacterial numbers showed a rapid decrease (28% in four days, followed by a relatively fast recovery (two weeks. The pollution favoured the increase of Gram-positive bacterial proportion (from around 25% to 33%Sandy sediment microbiota in both sites studied contained microorganisms able to use mineral or lipid oils as sole carbon sources, usually around 103-104/cm3, with variations according to the sediment grain size and substrate used.The biostimulation experiments showed that, in absence of water dynamism (and, implicitly, an efficient oxygenation, the addition of nitrogen and phosphorus can be ineffective and even inhibit the remediation process, probably due to eutrophication.

  12. On sustaining the ecology and livestock industry of the Bayanbuluk Grasslands

    Institute of Scientific and Technical Information of China (English)

    Adrian; R; WILLIAMS

    2010-01-01

    A short visit to the Bayanbuluk Grassland in the Tianshan Mountains, Xinjiang, PRC, revealed a number of environmental and livestock production problems, including grassland degradation, loss of grassland biodiversity, soil erosion and flash flooding downstream, decreased pasture productivity, and poor livestock nutrition (especially in winter) leading to stock losses and flocks and herds of low productivity. This paper describes those problems and then suggests some solutions. Short duration, high intensity grazing could be one of the solutions to both improving grassland condition and improving livestock nutrition. Local production of fodder crops for feeding in winter and spring deserves testing, using adapted strains of Alfalfa (Medicago sativa) and trialling fodder root crop production. It is important to realise that the land management objectives of scientists, administrators, herders and farmers may be similar, and that there are opportunities for land improvement through working together.

  13. Regularities of wind-erosion of different land-use types in Yongding River sandy land,Beijing

    Institute of Scientific and Technical Information of China (English)

    Yue Depeng; Liu Yongbing; Zang Runguo; Wang Xian

    2006-01-01

    The threshold wind velocity of a number of variables was studied in four different land-use types:farmland,forestland,wild grassland and a flood plain in the Yongding River sandy land in Beijing.The variables studied were transport of sand, underlying surface roughness,windblown sediment,wind-sand flow structure,soil mechanical composition and amount of wind erosion.The following conclusions were drawn: 1) The order of decreasing threshold of wind speed for sand displacement and surface roughness were forestland,wild grassland,farmland,sparse wild grassland and flood plain.2) There were significant differences in sand flux among different ground covers.At a height of 0-20 cm,the height increased while the sediment discharge percent of sand flux decreased;there were significant differences in the sand flow formation under different land-use types.3) The mechanical composition of sand particles consisted mainly of silver sand in the flood plain and sparse wild grassland,and of silver sand,particle silver sand and floury sand in other land-use types.4) The amounts of wind erosion and sand sediment were different among different land-use types.Increased vegetation cover and change in farming techniques were suggested to prevent and control wind erosion of sand and soil.

  14. Avian assemblages on altered grasslands

    Science.gov (United States)

    Knopf, Fritz L.

    1994-01-01

    Grasslands comprise 17% of the North American landscape but provide primary habitat for only 5% of native bird species. On the Great Plains, grasslands include an eastern component of tall grasses and a western component of short grasses, both of which have been regionally altered by removing native grazers, plowing sod, draining wetlands, and encouraging woody vegetation. As a group, populations of endemic bird species of the grasslands have declined more than others (including neotropical migrants) in the last quarter century. Individually, populations of the Upland Sandpiper and McCown’s Longspur have increased; the wetlands-associated Marbled Godwit and Wilson’s Phalarope appear stable; breeding ranges are shifting for the Ferruginous Hawk, Mississippi Kite, Short-eared Owl, Upland Sandpiper, Horned Lark, Vesper, Savannah, and Henslow’s sparrows, and Western Meadowlark; breeding habitats are disappearing locally for Franklin’s Gull, Dickcissel, Henslow’s and Grasshopper sparrows. Lark Bunting, and Eastern Meadowlark; and populations are declining throughout the breeding ranges for Mountain Plover, and Cassin’s and Clay-colored sparrows. Declines of these latter three species, and also the Franklin’s Gull, presumably are due to ecological phenomena on their respective wintering areas. Unlike forest species that winter in the neotropics, most birds that breed in the North American grasslands also winter on the continent and problems driving declines in grassland species are associated almost entirely with North American processes. Contemporary programs and initiatives hold promise for the conservation of breeding habitats for these birds. Ecological ignorance of wintering habits and habitats clouds the future of the endemic birds of grasslands, especially those currently experiencing widespread declines across breeding locales.

  15. Nitrogen transfer from forage legumes to nine neighbouring plants in a multi-species grassland

    DEFF Research Database (Denmark)

    Pirhofer-Walzl, Karin; Høgh Jensen, Henning; Eriksen, Jørgen

    2012-01-01

    Legumes play a crucial role in nitrogen supply to grass-legume mixtures for ruminant fodder. To quantify N transfer from legumes to neighbouring plants in multi-species grasslands we established a grass-legume-herb mixture on a loamy-sandy site in Denmark. White clover (Trifolium repens L.), red...... amounts of N from legumes than dicotyledonous plants which generally have taproots. Slurry application mainly increased N transfer from legumes to grasses. During the growing season the three legumes transferred approximately 40 kg N ha-1 to neighbouring plants. Below-ground N transfer from legumes...

  16. Temporal dynamics of soil aggregates and microbial parameters in permanent and recently established grasslands in the temperate zone

    Science.gov (United States)

    Linsler, Deborah; Taube, Friedhelm; Geisseler, Daniel; Joergensen, Rainer Georg; Ludwig, Bernard

    2015-04-01

    While changes over time in soil aggregation or microbial parameters are well studied for arable soils, much less is known about such temporal variations in grassland soils. The objective of the present study was to determine the changes that occur within one year (between October 2010 and October 2011) for water-stable aggregate, microbial biomass carbon (Cmic) and ergosterol (as a proxy for fungal biomass) concentrations of a sandy soil under a permanent and recently established grasslands The analyzed treatments were (i) permanent grassland, (ii) grassland re-established after tillage of previous permanent grassland, and (iii) grassland established on arable land (both in September 2010). Temporal variations were found for the aggregate distribution and ergosterol concentration in the permanent grassland. For instance, the concentration of large macroaggregates (>2000 μm) in the surface soil (0-10 cm) varied strongly, with the highest concentration (mean ± standard error) in October 2011 (666 ± 12 g kg-1) and a 3.2-fold lower concentration in May 2011. An explanation could be less rainfall and decreasing soil moisture contents in May compared to October, which may have decreased the stability of this fraction. A multiple linear regression analysis showed that the large macroaggregate concentration was well described (R2=0.60) by the gravimetric moisture content, the Cmic concentration and the pH. After the tillage event in the grassland and the subsequent grassland renovation, the concentrations of large macroaggregate, Cmic and ergosterol decreased in the surface soil, while no difference was found in the soil profile (0-40 cm). In the first year after the conversion of arable land into grassland, the concentrations of Cmic and ergosterol increased by a factor of 1.4 and 3.3, respectively, in the surface soil layer, while the macroaggregate concentration was not affected. This study indicates that the aggregate dynamic in grassland is not only affected by

  17. [Simulation alfalfa growth in Wulanbuhe sandy region].

    Science.gov (United States)

    Bai, Wenming; Bao, Xuemei

    2002-12-01

    Based on the theories of accumulated temperature and on the physio-ecological characteristics of Medicago sativa, a simulation model for its growth under soil water stress in arid sandy region was developed. The model was mainly composed of four modules: the stage module of growth, the dynamic module of leaf area index, the accumulated module of dry matter, and the distributive module of dry matter. After simulating and calculating, the model could be used to predict the growing progress and dynamic changes of leaf area and yield for herbage in sandy region. The result shows that the application of the model to production is usually effective.

  18. Soil organic matter dynamics under different land-use in grasslands in Inner Mongolia (northern China

    Directory of Open Access Journals (Sweden)

    L. Zhao

    2014-04-01

    Full Text Available We examined bulk soil properties and molecular biomarker distributions in surface soils from Inner Mongolia grasslands in order to understand the responses of soil organic matter to different land-use. The total of sixteen soils were collected from severely degraded grassland by overgrazing (DG, native grassland without apparent anthropogenic disturbance (NG, groundwater-sustaining grassland (GG and restored grassland from previous potato cropland (RG. Compared to NG, soil organic carbon content was lower by 50% in DG, but higher by six-fold in GG and one-fold in RG. The δ13C values of soil organic carbon were −24.2 ± 0.6‰ in DG, −24.9 ± 0.6‰ in NG, −25.1 ± 0.1‰ in RG and −26.2 ± 0.6‰ in GG, reflecting different degradation degrees of soil organic matter or different water use efficiencies. The soils in DG contained the lowest abundance of aliphatic lipids (n-alkanes, n-alkanols, n-alkanoic acids, ω-hydroxylalkanoic acids and α-hydroxylalkanoic acids and lignin-phenols, suggesting selective removal of these biochemically recalcitrant biomarkers with grassland degradation by microbial respiration or wind erosion. Compared to NG, the soils in GG and RG increased ω-hydroxylalkanoic acids by 60–70%, a biomarker for suberin from roots, and increased α-hydroxylalkanoic acids by 10–20%, a biomarker for both cutin and suberin. Our results demonstrate that the groundwater supply and cultivation-restoration practices in Inner Mongolia grasslands not only enhance soil organic carbon sequestration, but also change the proportions of shoot vs. root-derived carbon in soils. This finding has important implications for global carbon cycle since root derived aliphatic carbon has a longer residence time than the aboveground tissue-derived carbon in soils.

  19. Soil organic matter dynamics under different land use in grasslands in Inner Mongolia (northern China)

    Science.gov (United States)

    Zhao, L.; Wu, W.; Xu, X.; Xu, Y.

    2014-09-01

    We examined bulk soil properties and molecular biomarker distributions in surface soils from Inner Mongolian grasslands in order to understand the responses of soil organic matter to different land use. A total of 16 soils were collected from severely degraded grassland by overgrazing (DG), native grassland without apparent anthropogenic disturbance (NG), groundwater-sustaining grassland (GG) and restored grassland from previous potato cropland (RG). Compared to NG, soil organic carbon content was lower by 50% in DG, but higher by six-fold in GG and one-fold in RG. The δ13C values of soil organic carbon were -24.2 ± 0.6‰ in DG, -24.9 ± 0.6‰ in NG, -25.1 ± 0.1‰ in RG and -26.2 ± 0.6‰ in GG, reflecting different degradation degrees of soil organic matter or different water use efficiencies. The soils in DG contained the lowest abundance of aliphatic lipids (n-alkanes, n-alkanols, n-alkanoic acids, ω-hydroxylalkanoic acids and α-hydroxyalkanoic acids) and lignin-phenols, suggesting selective removal of these biochemically recalcitrant biomarkers with grassland degradation by microbial respiration or wind erosion. Compared to NG, the soils in GG and RG increased ω-hydroxylalkanoic acids by 60-70%, a biomarker for suberin from roots, and increased α-hydroxylalkanoic acids by 10-20%, a biomarker for both cutin and suberin. Our results demonstrate that the groundwater supply and cultivation-restoration practices in Inner Mongolian grasslands not only enhance soil organic carbon sequestration, but also change the proportions of shoot- versus root-derived carbon in soils. This finding has important implications for the global carbon cycle since root-derived aliphatic carbon has a longer residence time than the aboveground tissue-derived carbon in soils.

  20. Soil organic matter dynamics under different land-use in grasslands in Inner Mongolia (northern China)

    Science.gov (United States)

    Zhao, L.; Wu, W.; Xu, X.; Xu, Y.

    2014-04-01

    We examined bulk soil properties and molecular biomarker distributions in surface soils from Inner Mongolia grasslands in order to understand the responses of soil organic matter to different land-use. The total of sixteen soils were collected from severely degraded grassland by overgrazing (DG), native grassland without apparent anthropogenic disturbance (NG), groundwater-sustaining grassland (GG) and restored grassland from previous potato cropland (RG). Compared to NG, soil organic carbon content was lower by 50% in DG, but higher by six-fold in GG and one-fold in RG. The δ13C values of soil organic carbon were -24.2 ± 0.6‰ in DG, -24.9 ± 0.6‰ in NG, -25.1 ± 0.1‰ in RG and -26.2 ± 0.6‰ in GG, reflecting different degradation degrees of soil organic matter or different water use efficiencies. The soils in DG contained the lowest abundance of aliphatic lipids (n-alkanes, n-alkanols, n-alkanoic acids, ω-hydroxylalkanoic acids and α-hydroxylalkanoic acids) and lignin-phenols, suggesting selective removal of these biochemically recalcitrant biomarkers with grassland degradation by microbial respiration or wind erosion. Compared to NG, the soils in GG and RG increased ω-hydroxylalkanoic acids by 60-70%, a biomarker for suberin from roots, and increased α-hydroxylalkanoic acids by 10-20%, a biomarker for both cutin and suberin. Our results demonstrate that the groundwater supply and cultivation-restoration practices in Inner Mongolia grasslands not only enhance soil organic carbon sequestration, but also change the proportions of shoot vs. root-derived carbon in soils. This finding has important implications for global carbon cycle since root derived aliphatic carbon has a longer residence time than the aboveground tissue-derived carbon in soils.

  1. Effects of land use/land cover on diurnal temperature range in the temperate grassland region of China.

    Science.gov (United States)

    Shen, Xiangjin; Liu, Binhui; Lu, Xianguo

    2017-01-01

    As a fragile ecological zone, the temperate grassland region of China has experienced dramatic land use/land cover (LULC) changes due to human disturbances. So far, the impacts of LULC change on climate especially the diurnal temperature range (DTR) in this region are still not well understood. Based on the OMR (observation minus reanalysis) method, this study investigated the effects of LULC on DTR in the temperate grassland region of China. Considering the possible uncertainty of the results due to spatial resolution of the reanalysis dataset, two reanalysis datasets with different spatial resolutions were utilized. Results showed that LULC generally contributed to the decline of DTR in the temperate grassland region of China during 1980 to 2005. Due to different warming effects on monthly maximum temperature (Tmax) and minimum temperature (Tmin), grassland and forest tend to slightly decrease monthly DTR (approximately -0.053 to -0.050°C/decade and approximately -0.059 to -0.055°C/decade, respectively), while bare land has a slightly positive effect on DTR (approximately 0.018-0.021°C/decade). By contrast, cropland and urban tend to slightly decrease Tmax, obviously increase Tmin and thus result in a rapid decline of DTR (approximately -0.556 to -0.503°C/decade and approximately -0.617 to -0.612°C/decade, respectively). In the temperate grassland region of China, grassland vegetation changes due to human disturbances can have some effects on DTR mainly by changing the Tmax. Conversion from grassland to cropland could decrease the DTR by slowing down the increase of Tmax. But the conversion from grassland to bare land, as well as the reduction of grassland vegetation cover will increase Tmax, and consequently the DTR. The results suggest that grassland degradation is likely to result in daylight warming and increased DTR in the temperate grassland region of China. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Interstitial meiofauna of Namib sandy beaches

    African Journals Online (AJOL)

    1988-03-16

    Mar 16, 1988 ... sandy beaches on the Namibian coast, Langstrand and Cape Cross. A transverse ... prominent in the mid-shore at Cape Cross but occurred in low numbers at Langstrand , where archiannelids ... Koop (1983) recorded the faunal composition of local .... four replicate sediment cores were taken at 15 cm.

  3. Bibliography of sandy beaches and sandy beach organisms on the African continent

    CSIR Research Space (South Africa)

    Bally, R

    1986-01-01

    Full Text Available This bibliography covers the literature relating to sandy beaches on the African continent and outlying islands. The bibliography lists biological, chemical, geographical and geological references and covers shallow marine sediments, surf zones off...

  4. Effects of plant species richness on 13C assimilate partitioning in artificial grasslands of different established ages

    Science.gov (United States)

    Xu, Longhua; Yao, Buqing; Wang, Wenying; Wang, Fangping; Zhou, Huakun; Shi, Jianjun; Zhao, Xinquan

    2017-01-01

    Artificial grasslands play a role in carbon storage on the Qinghai-Tibetan Plateau. The artificial grasslands exhibit decreased proportions of graminate and increased species richness with age. However, the effect of the graminate proportions and species richness on ecosystem C stocks in artificial grasslands have not been elucidated. We conducted an in situ13C pulse-labeling experiment in August 2012 using artificial grasslands that had been established for two years (2Y), five years (5Y), and twelve years (12Y). Each region was plowed fallow from severely degraded alpine meadow in the Qinghai-Tibetan Plateau. The 12Y grassland had moderate proportions of graminate and the highest species richness. This region showed more recovered 13C in soil and a longer mean residence time, which suggests species richness controls the ecosystem C stock. The loss rate of leaf-assimilated C of the graminate-dominant plant species Elymus nutans in artificial grasslands of different ages was lowest in the 12Y grassland, which also had the highest species richness. Thus the lower loss rate of leaf-assimilated C can be partially responsible for the larger ecosystem carbon stocks in the 12Y grassland. This finding is a novel mechanism for the effects of species richness on the increase in ecosystem functioning.

  5. 77 FR 74341 - Establishing the Hurricane Sandy Rebuilding Task Force

    Science.gov (United States)

    2012-12-14

    ... the Hurricane Sandy Rebuilding Task Force By the authority vested in me as President by the.... Hurricane Sandy made landfall on October 29, 2012, resulting in major flooding, extensive structural damage... assist the affected region. A disaster of Hurricane Sandy's magnitude merits a comprehensive...

  6. Rapid decline of a grassland system and its ecological and conservation implications.

    Directory of Open Access Journals (Sweden)

    Gerardo Ceballos

    Full Text Available One of the most important conservation issues in ecology is the imperiled state of grassland ecosystems worldwide due to land conversion, desertification, and the loss of native populations and species. The Janos region of northwestern Mexico maintains one of the largest remaining black-tailed prairie dog (Cynomys ludovicianus colony complexes in North America and supports a high diversity of threatened and endangered species. Yet, cattle grazing, agriculture, and drought have greatly impacted the region. We evaluated the impact of human activities on the Janos grasslands, comparing changes in the vertebrate community over the last two decades. Our results reveal profound, rapid changes in the Janos grassland community, demonstrating large declines in vertebrate abundance across all taxonomic groups. We also found that the 55,000 ha prairie dog colony complex has declined by 73% since 1988. The prairie dog complex has become increasingly fragmented, and their densities have shown a precipitous decline over the years, from an average density of 25 per ha in 1988 to 2 per ha in 2004. We demonstrated that prairie dogs strongly suppressed woody plant encroachment as well as created open grassland habitat by clearing woody vegetation, and found rapid invasion of shrubland once the prairie dogs disappeared from the grasslands. Comparison of grasslands and shrublands showed markedly different species compositions, with species richness being greatest when both habitats were considered together. Our data demonstrate the rapid decline of a grassland ecosystem, and documents the dramatic loss in biodiversity over a very short time period concomitant with anthropogenic grassland degradation and the decline of a keystone species.

  7. A Leguminous Shrub (Caragana microphylla) in Semiarid Sandy Soils of North China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tong-Hui; SU Yong-Zhong; CUI Jian-Yuan; ZHANG Zhi-Hui; CHANG Xue-Xiang

    2006-01-01

    Caragana microphylla Lam., a pioneer leguminous shrub species for vegetation re-establishment, is widely distributed in the semi-fixed and fixed sandy lands of the Horqin region. Some soil chemical and physical properties were measured under the canopy of C. microphylla and in the adjacent open areas to determine the effects of individual shrubs on soil properties. The influence of isolated C. microphylla on chemical and physical properties of the topsoil was significantly different between plots under the shrub canopy and in the shrub interspaces. Beneath the shrub canopy greater amounts of fine particle fractions, a higher water-holding capacity, and a lower bulk density, as well as higher aboveground and belowground litter biomass were found. Soil organic C and total N concentrations were 23%-31.6% and 14%-27.2% higher under the shrub canopies than in the shrub interspaces, respectively, giving rise to "islands of fertility". In a desertified sandy grassland ecosystem, C. microphylla was believed to play a major role in organic C sequestration, N accumulation, and the hydrologic cycle. Additionally, it has been found to be of ecological importance for vegetative restoration and reversal of desertification.

  8. Spatial distribution of grassland productivity and land use in Europe

    NARCIS (Netherlands)

    Smit, H.J.; Metzger, M.J.; Ewert, F.

    2008-01-01

    Grasslands are an important land use in Europe with essential functions for feed and ecosystem service supply. Impact assessment modelling of European agriculture and the environment needs to consider grasslands and requires spatially explicit information on grassland distribution and productivity,

  9. Spatial distribution of grassland productivity and land use in Europe

    NARCIS (Netherlands)

    Smit, H.J.; Metzger, M.J.; Ewert, F.

    2008-01-01

    Grasslands are an important land use in Europe with essential functions for feed and ecosystem service supply. Impact assessment modelling of European agriculture and the environment needs to consider grasslands and requires spatially explicit information on grassland distribution and productivity,

  10. Carbon balance of renovated grasslands: input- or output-driven?

    Science.gov (United States)

    Choncubhair, Órlaith Ní; Osborne, Bruce; Lanigan, Gary

    2015-04-01

    Temperate grasslands constitute over 30% of the Earth's naturally-occurring biomes and make an important contribution towards the partial mitigation of anthropogenic greenhouse gas emissions by terrestrial ecosystems. In permanent temperate grasslands, biomass production and sward quality can deteriorate over time and periodic renovation activities, involving soil tillage and reseeding, are commonly carried out to halt this decline. Long-term cultivation of agricultural land has been associated with soil aggregate degradation and reduced soil carbon storage. However, the impact of these single tillage disturbances on C cycling in grasslands is less clear. This study evaluated gaseous and dissolved organic carbon (DOC) losses following a single tillage event by subjecting grassland lysimeters with contrasting soil drainage characteristics to simulated conventional inversion or minimum tillage. Field-scale CO2 emissions after conventional tillage were also quantified and empirically modelled over short- and medium-term timeframes to delineate the ecosystem response to environmental variables. Soil moisture was the limiting determinant of ecosystem carbon release following conventional tillage. Freshly-tilled soils were associated with reduced water retention and increased sensitivity to soil moisture, which was particularly pronounced following rewetting events. Significantly elevated but ephemeral CO2 effluxes were detected in the hours following inversion ploughing, however tillage disturbance did not generate significantly enhanced C emission rates in the medium term. Equally, DOC losses were not significantly amplified by conventional tillage compared with conservative minimum tillage and were predominantly controlled by soil drainage across tillage regimes. Our results suggest that a net ecosystem source of 120 to 210 g C m-2 over an approximately two-month period was most likely a consequence of reduced productivity and C input rather than enhanced soil CO2

  11. Degradation of zearalenone and ochratoxin A in three Danish agricultural soils

    DEFF Research Database (Denmark)

    Mortensen, G.K.; Strobel, B.W.; Hansen, H.C.B.

    2006-01-01

    Degradation of two mycotoxins: zearalenone (ZON) produced by species of Fusarium and ochratoxin A (OTA) produced by species of Penicillium were followed in pot experiments using agricultural topsoils from Danish experimental farms: a sandy soil, a sandy clay soil and a gyttja soil with a high...

  12. Screening of cellulose decomposing fungi in sandy dune soil of Horqin Sandy Land

    Institute of Scientific and Technical Information of China (English)

    ShaoKun Wang; XueYong Zhao; XiaoAn Zuo; XinPing Liu; Hao Qu; Wei Mao; JianYing Yun

    2015-01-01

    Cellulose decomposing fungi play an important role in litter decomposition and are decisive in nutrient cycling in sandy land ecosystems. Thirty-one strains were isolated to select efficient cellulose decomposers, and four efficient cellulose decomposing fungi (NM3-1, NM3-2, NM3-3, and NM3-4) were screened using a CMC (carboxymethyl cellulose) carbon source in dune soil of Horqin Sandy Land. They were identified as Asperigillus calidoustus, Fusarium oxysporum, Fusarium solani, and Hypocrea lixii by rDNA-ITS molecular biological methods. Cloth decomposition rates were 15.71%, 15.89%, 17.29%, and 17.89%by the four efficient decomposers incubated for 30 days, respectively. Screening of efficient cellulose decomposers can not only increase the dune soil functional microbe bank, but can also accelerate litter decom-position and available nutrient input in the Horqin Sandy Land.

  13. Efficiency of different methods for seeding grasslands

    Directory of Open Access Journals (Sweden)

    Vesna Očić

    2009-12-01

    Full Text Available In Croatia, the economic effects of different grassland sowing methods are still insufficiently explored. In order to detect the difference between grassland sowing methods a three-year field trialswere performed to determine the production and economic value of grasslands sown by: direct seeding into corn stubble field with row distance of 18 cm (DSK18 or ii 9 cm (DSK9, iii conventional seeding (KS, iv sod-seeding in existing grassland (RPTDS and v natural grassland as control (KPT. In the whole research period the highest average green mass productivity was achieved by conventional seeding (38.84 t/ha, while the lowest green mass yield had natural grassland and sod-seeded natural grassland (10.92 and 11.63 t/ha of green mass. Observed per unit of area, difference in production values ranged from 3276 kn, which was achieved with natural grass to 17.478 kn/ha, which was achieved by conventional seeding. Looking at the production efficiency, direct seeding into corn stubble field with row distance of 9 cm (3.17 has the largest coefficient, while natural grassland is on the economy border with coefficient 1.00. Relations between invested and obtained, which was measured with value of Gross Margin, is in range from 6 kn/ha (natural grassland to 11.420 kn/ha, which was achieved by conventional seeding. Looking at the production of hay, conventional seeding with 7.11 t/ha of hay had the maximum productivity, while the natural grassland and sod-seeded natural grassland had the lowest production (2.87 and 2.86 t/ha.

  14. Combining social policy and scientific knowledge with stakeholder participation can benefit on salted grassland production in Northeast China

    Science.gov (United States)

    Wang, Deli; Yang, Zhiming; Wang, Ling; Sun, Wei

    2015-04-01

    Soil salinization is a serious environmental problem across the Eurasian steppes, where millions people have been living for at least five thousand years and will still depend on it in the near future. During the last several decades, ecologists and grassland scientists have done much research on rational grassland utilization avoiding land degradation and reduction in ecological services. Meanwhile, the central and local governments took some attempts of agricultural policy and ecological subsidy to mitigate large scale land salinization in Northeast China. Fortunately, more and more farmers and stakeholders begin to adopt rational grassland management with the guidance of scientists and the help of local governments. However, up to date, there is still a gap between farmers, scientists and governments, which often negatively affect grassland production and remission of soil salinization in these areas. We conducted a case study on sustainable grassland production adapted to steppe salinization funded by EC project from 2011 to 2013. Our goal is trying to establish a mode of adaptive grassland management integrating previous scientific knowledge (grazing and seeding), current agricultural policies (ecological subsidy) and stakeholders' participation or performance. The study showed that: A. Despite of some grassland utilization techniques available for stakeholders (regulating stocking rate and seeding in pastures, or planting high quality forages), they tended to take the simplest action to enhance animal production and prevent grassland salinization; B. Compared to educating or training stakeholders, demonstration of grazing management is the most effective mean for knowledge dissemination or technology transfer; C. Ecological subsidy is absolutely welcome to the local people, and technology transfer became easier when combined with ecological subsidy; D. There was a contrasting effect in grassland production and land degradation mitigation for experimental farm

  15. BVOC fluxes above mountain grassland

    Directory of Open Access Journals (Sweden)

    I. Bamberger

    2010-05-01

    Full Text Available Grasslands comprise natural tropical savannah over managed temperate fields to tundra and cover one quarter of the Earth's land surface. Plant growth, maintenance and decay result in volatile organic compound (VOCs emissions to the atmosphere. Furthermore, biogenic VOCs (BVOCs are emitted as a consequence of various environmental stresses including cutting and drying during harvesting. Fluxes of BVOCs were measured with a proton-transfer-reaction-mass-spectrometer (PTR-MS over temperate mountain grassland in Stubai Valley (Tyrol, Austria over one growing season (2008. VOC fluxes were calculated from the disjunct PTR-MS data using the virtual disjunct eddy covariance method and the gap filling method. Methanol fluxes obtained with the two independent flux calculation methods were highly correlated (y = 0.95×−0.12, R2 = 0.92. Methanol showed strong daytime emissions throughout the growing season – with maximal values of 9.7 nmol m−2 s−1, methanol fluxes from the growing grassland were considerably higher at the beginning of the growing season in June compared to those measured during October (2.5 nmol m−2 s−1. Methanol was the only component that exhibited consistent fluxes during the entire growing periods of the grass. The cutting and drying of the grass increased the emissions of methanol to up to 78.4 nmol m−2 s−1. In addition, emissions of acetaldehyde (up to 11.0 nmol m−2 s−1, and hexenal (leaf aldehyde, up to 8.6 nmol m−2 s−1 were detected during/after harvesting.

  16. Effects of forest expansion on mountain grassland

    DEFF Research Database (Denmark)

    Guidi, Claudia; Magid, Jakob; Rodeghiero, Mirco

    2014-01-01

    Background and aims. Grassland abandonment followed by forest succession is the dominant land-use change in the European Alps. We studied the impact of current forest expansion on mountain grassland on changes in physical soil organic carbon (SOC) fractions along a land-use and management gradient...

  17. Grasslands Management Plan : Tamarac National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The goal of this Grassland Management Plan for Tamarac NWR is to provide a variety of quality grasslands, by the year 1999 totaling 2,500 acres and eventually 5,000...

  18. Desert grassland and shrubland ecosystems [chapter 5

    Science.gov (United States)

    Samuel R. Loftin; Richard Agllilar; Alice L. Chung-MacCoubrey; Wayne A. Robbie

    1995-01-01

    The productivity, stability, and health of the Middle Rio Grande Basin, arid and semiarid grassland and shrub land ecosystems depend upon complex interactions. These relationships occur between factors such as climate, domestic livestock, and wildlife use, and human activities such as urban development, agriculture, and recreation. These grassland/ shrub land...

  19. Threats to sandy beach ecosystems: A review

    Science.gov (United States)

    Defeo, Omar; McLachlan, Anton; Schoeman, David S.; Schlacher, Thomas A.; Dugan, Jenifer; Jones, Alan; Lastra, Mariano; Scapini, Felicita

    2009-01-01

    We provide a brief synopsis of the unique physical and ecological attributes of sandy beach ecosystems and review the main anthropogenic pressures acting on the world's single largest type of open shoreline. Threats to beaches arise from a range of stressors which span a spectrum of impact scales from localised effects (e.g. trampling) to a truly global reach (e.g. sea-level rise). These pressures act at multiple temporal and spatial scales, translating into ecological impacts that are manifested across several dimensions in time and space so that today almost every beach on every coastline is threatened by human activities. Press disturbances (whatever the impact source involved) are becoming increasingly common, operating on time scales of years to decades. However, long-term data sets that describe either the natural dynamics of beach systems or the human impacts on beaches are scarce and fragmentary. A top priority is to implement long-term field experiments and monitoring programmes that quantify the dynamics of key ecological attributes on sandy beaches. Because of the inertia associated with global climate change and human population growth, no realistic management scenario will alleviate these threats in the short term. The immediate priority is to avoid further development of coastal areas likely to be directly impacted by retreating shorelines. There is also scope for improvement in experimental design to better distinguish natural variability from anthropogenic impacts. Sea-level rise and other effects of global warming are expected to intensify other anthropogenic pressures, and could cause unprecedented ecological impacts. The definition of the relevant scales of analysis, which will vary according to the magnitude of the impact and the organisational level under analysis, and the recognition of a physical-biological coupling at different scales, should be included in approaches to quantify impacts. Zoning strategies and marine reserves, which have not

  20. Analysis of Grassland Vegetation of the Southwest Heilongjiang Steppe (China) Using the Power Law

    Institute of Scientific and Technical Information of China (English)

    Mikinori TSUIKI; Yu-Sheng WANG; Yiruhan; Michio TSUTSUMI; Masae SHIYOMI

    2005-01-01

    In 1997, we conducted a vegetation survey in three semi-arid natural grasslands (steppes) withdifferent livestock grazing intensities in Southwest Heilongjiang Province, China. The dominant grasslandspecies was the grass Stipa baicalensis Roshev. Grasslands with light, intermediate, and heavy grazingintensities were located 10, 5, and 2 km from a village, respectively. Villagers use the steppe to raise cattle,horses, sheep, and goats. Each of the three grasslands was surveyed by placing 100 quadrats (50 cm×50 cm)along a 50 m line transect. Each quadrat was divided into four equal areas (25 cm×25 cm; S-quadrats) and allplant species occurring in each of these smaller areas were identified and recorded. These data were summa-rized into frequency distributions and the percentage of S-quadrats containing a given species and thevariance of each species were estimated. The power law was applied to these estimates. The power law wasused to evaluate the spatial heterogeneity and frequency of occurrence for each species in the grasslandcommunity. The lightly grazed grassland exhibited high spatial heterogeneity (caused by large plant size),the highest species diversity, and a high occurrence of S. baicalensis. In contrast, the heavily grazedgrassland exhibited high spatial heterogeneity (caused by patchy populations of small plant size), lowspecies diversity, and a low occurrence of S. baicalensis. We judged that the heavily grazed grassland wasovergrazed and exclusion of livestock from the degraded areas is necessary for recovery.

  1. The dark side is not fastidious--dark septate endophytic fungi of native and invasive plants of semiarid sandy areas.

    Science.gov (United States)

    Knapp, Dániel G; Pintye, Alexandra; Kovács, Gábor M

    2012-01-01

    Dark septate endophytic (DSE) fungi represent a frequent root-colonizing fungal group common in environments with strong abiotic stress, such as (semi)arid ecosystems. This work aimed to study the DSE fungi colonizing the plants of semiarid sandy grasslands with wood steppe patches on the Great Hungarian Plain. As we may assume that fungi colonizing both invasive and native species are generalists, root associated fungi (RAF) were isolated from eight native and three invasive plant species. The nrDNA sequences of the isolates were used for identification. To confirm that the fungi were endophytes an artificial inoculation system was used to test the isolates: we considered a fungus as DSE if it colonized the roots without causing a negative effect on the plant and formed microsclerotia in the roots. According to the analyses of the ITS sequence of nrDNA the 296 isolates clustered into 41 groups. We found that 14 of these 41 groups were DSE, representing approximately 60% of the isolates. The main DSE groups were generalist and showed no specificity to area or season and colonized both native and invasive species, demonstrating that exotic plants are capable of using the root endophytic fungi of the invaded areas. The DSE community of the region shows high similarity to those found in arid grasslands of North America. Taking into account a previous hypothesis about the common root colonizers of those grasslands and our results reported here, we hypothesize that plants of (semi)arid grasslands share common dominant members of the DSE fungal community on a global scale.

  2. Carbon storage of Mediterranean grasslands

    Directory of Open Access Journals (Sweden)

    Corona, Piermaria

    2016-06-01

    Full Text Available Secondary grasslands are one of the most common vegetation types worldwide. In Europe, and in the Mediterranean basin, human activities have transformed many woodlands into secondary grasslands. Despite their recognized role in the global carbon cycle, very few data are available for estimating the biomass of Mediterranean grasslands. We developed linear regression models in order to predict the biomass of two native Mediterranean grasses (Ampelodesmos mauritanicus and Hyparrhenia hirta and an invasive alien grass (Pennisetum setaceum. Ampelodesmos mauritanicus is very common throughout the Mediterranean basin, mostly on north-facing slopes, H. hirta characterizes thermo-xeric grasslands, while P. setaceum is an alien species that is rapidly spreading along coastal areas. The measured morphometric attributes of individual plants as potential predictors were considered. The validation results corroborate the ability of the established models to predict above ground and total biomass of A. mauritanicus and P. setaceum. We also evaluated the total biomass per hectare for each species. The highest biomass per hectare was found for A. mauritanicus, whereas biomass was higher for H. hirta than for P. setaceum. The replacement of H. hirta by P. setaceum may reduce the total carbon storage in the ecosystem; however, P. setaceum allocates more resources to the roots, thus increasing the more stable and durable pool of carbon in grasslands.Los pastizales secundarios son uno de los tipos de vegetación más comunes en todo el mundo. En Europa y en la cuenca mediterránea, las actividades humanas han transformado muchos bosques en pastizales secundarios. A pesar de su reconocido papel en el ciclo global del carbono, hay muy pocos datos disponibles para la estimación de la biomasa de los pastizales mediterráneos. Hemos desarrollado modelos de regresión lineal con el fin de predecir la biomasa de dos gramíneas nativas del Mediterráneo (Ampelodesmos

  3. Microbial Enzyme Activity and Carbon Cycling in Grassland Soil Fractions

    Science.gov (United States)

    Allison, S. D.; Jastrow, J. D.

    2004-12-01

    Extracellular enzymes are necessary to degrade complex organic compounds present in soils. Using physical fractionation procedures, we tested whether old soil carbon is spatially isolated from degradative enzymes across a prairie restoration chronosequence in Illinois, USA. We found that carbon-degrading enzymes were abundant in all soil fractions, including macroaggregates, microaggregates, and the clay fraction, which contains carbon with a mean residence time of ~200 years. The activities of two cellulose-degrading enzymes and a chitin-degrading enzyme were 2-10 times greater in organic matter fractions than in bulk soil, consistent with the rapid turnover of these fractions. Polyphenol oxidase activity was 3 times greater in the clay fraction than in the bulk soil, despite very slow carbon turnover in this fraction. Changes in enzyme activity across the restoration chronosequence were small once adjusted for increases in soil carbon concentration, although polyphenol oxidase activity per unit carbon declined by 50% in native prairie versus cultivated soil. These results are consistent with a `two-pool' model of enzyme and carbon turnover in grassland soils. In light organic matter fractions, enzyme production and carbon turnover both occur rapidly. However, in mineral-dominated fractions, both enzymes and their carbon substrates are immobilized on mineral surfaces, leading to slow turnover. Soil carbon accumulation in the clay fraction and across the prairie restoration chronosequence probably reflects increasing physical isolation of enzymes and substrates on the molecular scale, rather than the micron to millimeter scale.

  4. Hurricane Sandy science plan: coastal impact assessments

    Science.gov (United States)

    Stronko, Jakob M.

    2013-01-01

    Hurricane Sandy devastated some of the most heavily populated eastern coastal areas of the Nation. With a storm surge peaking at more than 19 feet, the powerful landscape-altering destruction of Hurricane Sandy is a stark reminder of why the Nation must become more resilient to coastal hazards. In response to this natural disaster, the U.S. Geological Survey (USGS) received a total of $41.2 million in supplemental appropriations from the Department of the Interior (DOI) to support response, recovery, and rebuilding efforts. These funds support a science plan that will provide critical scientific information necessary to inform management decisions for recovery of coastal communities, and aid in preparation for future natural hazards. This science plan is designed to coordinate continuing USGS activities with stakeholders and other agencies to improve data collection and analysis that will guide recovery and restoration efforts. The science plan is split into five distinct themes: coastal topography and bathymetry, impacts to coastal beaches and barriers, impacts of storm surge, including disturbed estuarine and bay hydrology, impacts on environmental quality and persisting contaminant exposures, impacts to coastal ecosystems, habitats, and fish and wildlife. This fact sheet focuses assessing impacts to coastal beaches and barriers.

  5. 全膜双垄沟播技术改良荒漠化退化草原的研究(英文)%Effect of Planting in Furrow and Whole Plasticfilm Mulching on Double Ridges on Improvement of Degraded Desert Grassland

    Institute of Scientific and Technical Information of China (English)

    朱建宁; 彭文栋; 张秀红; 刘华; 高婷

    2012-01-01

    [目的]探讨全膜双垄沟播技术改良荒漠化退化草原的效果,以期为扩大该技术的应用领域提供理论依据和技术贮备。[方法]在宁夏盐池荒漠化退化草原中采用常规方法补播丛生禾本科牧草,并对其进行起垄覆黑膜、起垄覆透明膜、起垄不覆膜和不起垄不覆膜平播的4种保育处理,通过分析各处理的土壤含水率变化规律及其对补播苗生长的影响,寻找最优处理方式。[结果]从7月到11月起垄覆黑膜、起垄覆透明膜、起垄不覆膜和平播4个处理的土壤平均含水率分别为9.88%、9.24%、8.75%和8.13%,各处理间差异显著;补播牧草的成活率分别是96.2%、93.4%、45.6%和28.3%,覆膜相对不覆膜成活率达到极显著水平。其中以覆黑膜具有较大优势,其垄顶土壤含水率有"削峰填谷"的缓冲作用,覆黑膜土壤水分含量比平种提高了21.5%,且对于1m以下土壤的水分补充量也是最大的。覆膜虽然增加了费用,但从总体效益分析,利润高于不覆膜。[结论]该研究为起垄覆黑膜技术在荒漠化退化的草原补播改良中的推广应用奠定了试验基础。%[Objective] This study aimed to provide theoretical basis and technologies for the application of planting in furrow and whole plastic-film mulching on double ridges. [Method] The conventional method was used to re-seed the bunch Gramineous forage in the degraded desert grassland in Yanchi, Ningxia Hui Autonomous Region. Four kinds of conservation treatments, namely, ridging with black film mulching, ridging with transparent film mulching, ridging with no mulching and the flatplanting with no ridging and mulching were conducted to the forage to analyze the effects of each treatment on soil moisture and seedling growth. [Result] From July to November, the moisture contents of ridging with black film mulching, ridging with transparent film mulching, ridging with no mulching and the flatplanting were

  6. THE PROBLEMATIC OF SANDY LANDS IN PARANAVAI MUNICIPALITY –PR

    Directory of Open Access Journals (Sweden)

    Marcelo Eduardo Freres Stipp

    2005-05-01

    Full Text Available The sandy lands are a process of scouring with sand forming a sandy area, which correspondsto a reworking of the sands due its constant mobility, involving the transformation of notsolids deposits is sandy areas. This work tried to establish the characterization of thisphenomenon of scouring with sand in a local level, occurring in arenaceous areas in theNortheast of the state of Paraná, specifically in the urban site of Paranavaí. It was also madean evaluation of the environmental degradation as well as different causes for what provokedthese sandy areas. Being an area with a high level of soil decomposition with the highwaysroutes crossing it, it was necessary, besides bibliographic data that allowed a theoretical basis,a research applied in order to supply subsides for future planning related to the spaceorganization. The evolution of the use and soil occupation in this area has been processedwithin an urban planning which considered by no account neither soil characteristic, thevegetation nor the predominant climate in that region. The mechanisms of region atmospherecirculation were analyzed, the alterations or attributes of the climate as well, aiming toidentify the genesis of the erosion sandy and possible time and space distribution. Initially, themain characteristics of the region were collected, components e processes working on the landmodel. It was observed how it worked and the use and occupation of the soil in past times andcurrently. During 2004, using the Environmental Fragility Letter, the areas of erosion wereidentified, ravines and strong erosion that compounds the first stages of the focused problem.The sandy land is a process that involves erosion, transport, e accumulation, meaning most oftimes the loosing of Biosphere productivity. For monitoring these risk areas some measuringcanes were made to measure the soil loss, which were used in several spots of erosion in theurban area in Paranavaí. The measurement happened in

  7. 78 FR 32296 - Second Allocation of Public Transportation Emergency Relief Funds in Response to Hurricane Sandy...

    Science.gov (United States)

    2013-05-29

    ... Response to Hurricane Sandy: Response, Recovery & Resiliency AGENCY: Federal Transit Administration (FTA... recipients most severely affected by Hurricane Sandy: the Metropolitan Transportation Authority, New Jersey... Federal Register notice, bringing the total amount of Hurricane Sandy Emergency Relief funds allocated...

  8. Grasshopper (Orthoptera: Acrididae) biodiversity and grassland ecosystems

    Institute of Scientific and Technical Information of China (English)

    ZHONG-WEI GUO; HONG-CHANG LI; YA-LING GAN

    2006-01-01

    Interesting results may arise by combining studies on the structure and function of ecosystems with that of biodiversity for certain species. Grasshopper biodiversity is the result of the evolution of grassland ecosystems; however, it also impacts on the structure and the function of those ecosystems. We consider there to be a close relationship between the health of grassland ecosystems and grasshopper biodiversity. The main problems involved in this relationship are likely to include: (i) grasshopper biodiversity and its spatial pattern; (ii) the effect of grasshopper biodiversity on the ecological processes of grassland ecosystems; (iii) the biodiversity threshold of grasshopper population explosions;(iv) the relationship between grasshopper biodiversity and the natural and human factors that affect grassland ecosystems; and (v) grasshopper biodiversity and the health of grassland ecosystems. The solutions to these problems may provide sound bases for controlling disasters caused by grasshoppers and managing grassland ecosystems in the west of China. In this paper, we introduced two concepts for grasshopper biodiversity, that is, "spatial pattern" and "biodiversity threshold". It is helpful to understand the action of the spatial pattern of grasshopper biodiversity on the ecological processes of grassland ecosystems and the effect of this spatial pattern on the health of those ecosystems, owing to the fact that, in the west of China, grasslands are vast and grasshoppers are widely distributed. Moreover, we inferred that the change in the level of component richness at each type of grasshopper biodiversity can make an impact on grassland ecosystems, and therefore, there is likely to be a threshold to grasshopper biodiversity for the stability and the sustainability of those ecosystems.

  9. Organic matter dynamics in coarse sandy calcareous soils

    NARCIS (Netherlands)

    Pronk, A.A.; Reuler, van H.

    2011-01-01

    The decomposition of organic matter in coarse sandy calcareous soils (beach sand) is thought to be much higher than in acid fine sandy soils but relatively little research is performed on these soils. Laboratory incubation experiments in which the release of soil carbon (C) is determined may overest

  10. Characterizing historical (1992-2010) transitions between grassland and cropland in mainland France through mining land-cover survey data

    Institute of Scientific and Technical Information of China (English)

    Ying Xiao; Catherine Mignolet; Jean-Franois Mari; Marc Benot

    2015-01-01

    Grassland, as one of the largest ecosystems on the earth, supports various goods and services to humanity. Historical y, humans have increased agricultural output primarily by cropland expansion and agricultural intensiifcation. The cropland area was primarily gained at the expense of grassland and forests. Apart from grassland conversion, increasing consumption of calorie-and meat-intensive diets drives the intensiifcation of livestock systems, which is shifting steadily from grazing to feeding with crops. To cope with the environmental degradation due to agriculture, various forms of‘green payment’ were implemented to promote the adoption of sustainable farming practices over the last two decades in the European Union. The aim of this study is to monitor the recent transitions (1992–2010) between grassland and cropland during two Common Agricultural Policy (CAP) reforms at the French mainland scale. We proposed an innovative approach to link grassland con-version to agricultural commodities and farming systems practices. We ifrst assessed the grassland-to-cropland conversion and further investigated the crop sequence patterns that were observed to be dominant after the conversion through mining land-cover survey data Teruti and Teruti-Lucas. We found the trends of the transitions between grassland and cropland over the two time intervals:The loss of grassland (1992–2003) and restoration or re-expansion of grassland (2006–2010) in mainland France. Our ifnding on the crop sequence patterns after the grassland conversion reveals two notable evolutions of agricultural production systems. These evolutions were related to the increase in the proportion of cropland in the total agricultural land use. One evolution was most likely inlfuenced by the demand for fodder:The conversion from grazing livestock to feeding livestock. Another evolution was the conversion from livestock production to ifeld crop production. Our results indicate that the intensiifcation of

  11. Mean age of carbon in fine roots from temperate forests and grasslands with different management

    Directory of Open Access Journals (Sweden)

    E. Solly

    2013-03-01

    Full Text Available Fine roots are the most dynamic portion of a plant's root system and a major source of soil organic matter. By altering plant species diversity and composition, soil conditions and nutrient availability, and consequently belowground allocation and dynamics of root carbon (C inputs, land-use and management changes may influence organic C storage in terrestrial ecosystems. In three German regions we measured fine root radiocarbon (14C content to estimate the mean time since C in root tissues was fixed from the atmosphere in 54 grassland and forest plots with different management and soil conditions. Although root biomass was on average greater in grasslands 5.1 ± 0.8 g (mean ± SE, n = 27 than in forests 3.1 ± 0.5 g (n = 27, the mean age of C in fine roots in forests averaged 11.3 ± 1.8 yr and was significantly older and more variable compared to grasslands 1.7 ± 0.4 yr. We further found that management affects the mean age of fine root C in temperate grasslands mediated by changes in plant species diversity and composition. Fine root mean C age is positively correlated to plant diversity (r = 0.65 and to the number of perennial species (r = 0.77. In temperate grasslands the mean age of fine root C is also influenced by the study region mainly driven by differences in soil characteristics and climate which reflect in plant composition variations, with averages of 0.7 ± 0.1 yr (n = 9 on mostly organic sandy soils in northern Germany and of 1.8 ± 0.3 yr (n = 9 and 2.6 ± 0.3 (n = 9 in more silty and clayey soils respectively in central and southern Germany. Our results indicate an internal redistribution of C in perennial species and suggest linkages between fine root C age and management in grasslands. These findings improve our ability to predict and model belowground C fluxes across broader spatial scales.

  12. Social-ecological dynamics of change and restoration attempts in the Chihuahuan Desert Grasslands of Janos Biosphere Reserve, Mexico

    Science.gov (United States)

    Shrub encroachment and grassland loss are widespread throughout the US-Mexico borderlands with negative consequences for production of livestock and ecosystem services. In this paper we detail the complex social and ecological phenomena associated with this pattern of degradation in a large area in ...

  13. Rediscovering community--reflections after Hurricane Sandy.

    Science.gov (United States)

    See, Sharon

    2013-01-01

    Hoboken, New Jersey, is a town of 50,000 residents located across the Hudson River from New York City. Most of Hoboken's infrastructure was compromised during Hurricane Sandy as a result of flooding and power outages that rendered many businesses inoperable, including all of the pharmacies in town. Despite a focus on emergency preparedness since Hurricane Katrina and 9/11, there were no contingencies in place to facilitate and assess the medication needs of the community in the event of a natural disaster. This essay describes how the author rediscovered the meaning of community, and through working with colleagues in other health care disciplines and non-health care volunteers, provided care to patients in suboptimal circumstances.

  14. Hurricane Sandy science plan: New York

    Science.gov (United States)

    Ransom, Clarice N.

    2013-01-01

    Hurricane Sandy is a stark reminder of why the Nation must become more resilient to coastal hazards. More than one-half of the U.S. population lives within 50 miles of a coast, and this number is increasing. The U.S. Geological Survey (USGS) is one of the largest providers of geologic and hydrologic information in the world. Federal, State, and local partners depend on the USGS science to know how to prepare for hurricane hazards and reduce losses from future hurricanes. The USGS works closely with other bureaus within the Department of the Interior, the Federal Emergency Management Agency, the National Oceanic Atmospheric Administration, the U.S. Army Corps of Engineers, the Environmental Protection Agency, and many State and local agencies to identify their information needs before, during, and after hurricanes.

  15. Nitrate reduction in an unconfined sandy aquifer

    DEFF Research Database (Denmark)

    Postma, Diederik Jan; Boesen, Carsten; Kristiansen, Henning;

    1991-01-01

    Nitrate distribution and reduction processes were investigated in an unconfined sandy aquifer of Quaternary age. Groundwater chemistry was studied in a series of eight multilevel samplers along a flow line, deriving water from both arable and forested land. Results show that plumes of nitrate...... processes of O2 and NO3- occur at rates that are fast compared to the rate of downward water transport. Nitrate-contaminated groundwater contains total contents of dissolved ions that are two to four times higher than in groundwater derived from the forested area. The persistence of the high content...... of total dissolved ions in the NO3- free anoxic zone indicates the downward migration of contaminants and that active nitrate reduction is taking place. Nitrate is apparently reduced to N2 because both nitrite and ammonia are absent or found at very low concentrations. Possible electron donors...

  16. Spatiotemporal dynamics of grassland aboveground biomass on the Qinghai-Tibet Plateau based on validated MODIS NDVI.

    Science.gov (United States)

    Liu, Shiliang; Cheng, Fangyan; Dong, Shikui; Zhao, Haidi; Hou, Xiaoyun; Wu, Xue

    2017-06-23

    Spatiotemporal dynamics of aboveground biomass (AGB) is a fundamental problem for grassland environmental management on the Qinghai-Tibet Plateau (QTP). Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) data can feasibly be used to estimate AGB at large scales, and their precise validation is necessary to utilize them effectively. In our study, the clip-harvest method was used at 64 plots in QTP grasslands to obtain actual AGB values, and a handheld hyperspectral spectrometer was used to calculate field-measured NDVI to validate MODIS NDVI. Based on the models between NDVI and AGB, AGB dynamics trends during 2000-2012 were analyzed. The results showed that the AGB in QTP grasslands increased during the study period, with 70% of the grasslands undergoing increases mainly in the Qinghai Province. Also, the meadow showed a larger increasing trend than steppe. Future AGB dynamic trends were also investigated using a combined analysis of the slope values and the Hurst exponent. The results showed high sustainability of AGB dynamics trends after the study period. Predictions indicate 60% of the steppe and meadow grasslands would continue to increase in AGB, while 25% of the grasslands would remain in degradation, with most of them distributing in Tibet.

  17. Grassland Management Plan : Sherburne National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Grasslands represent a significant habitat type an Sherburne National Wildlife Refuge. The rich diversity of plant and animal communities native to the area can and...

  18. Description of the Grassland Biome Project

    CSIR Research Space (South Africa)

    Mentis, MT

    1982-10-01

    Full Text Available The objectives, organization and research programme of the Grassland Biome Project are described against a background of the biome's ecological characteristics and environmental problems. Four principal research topics wil 1 be focused upon: (i...

  19. US Forest Service National Grassland Units

    Data.gov (United States)

    US Forest Service, Department of Agriculture — A map service on the www depicting National Grassland units designated by the Secretary of Agriculture and permanently held by the Department of Agriculture under...

  20. Land Protection Plan: Dakota Grassland Conservation Area

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Land Protection Plan for Dakota Grassland Conservation Area provides a description of the project, a description of the area and its resources, threats to the...

  1. The greenhouse gas balance of European grasslands

    Directory of Open Access Journals (Sweden)

    P. Ciais

    2010-08-01

    Full Text Available The long-term carbon balance (NBP of grasslands is estimated by combining scarce multi-year eddy-covariance observations at ecosystem observation sites where information on carbon inputs and harvesting removals is available. Following accounting for carbon leached to rivers, we estimated grasslands to be net carbon sinks of 74±10 g C m−2 yr−1. Uncertainties arise from the small number of sites and the short measurement period. Only 11 sites, out of a total of 20 grassland sites in Europe where eddy covariance systems are installed, were set-up for estimating NBP. These 11 selected sites are representative of intensive management practice and we lack information on disturbance history, such as plowing. This suggests that the grassland NBP estimate is likely biased towards overestimating the sink, compared to the European average. Direct measurements of Net Primary Productivity (NPP are not possible in grasslands given permanent biomass removal by grazing and mowing, uncertainties in rhizodeposition and production of volatile organic carbon compounds lost to the atmosphere. Therefore, the grassland process-based ecosystem model PASIM was used to estimate the spatial-temporal distribution of NPP, providing a European average value of 750±150 g C across extensively grazed, intensively grazed pastures, and forage production systems. In Europe the NPP of grasslands seems higher than that of croplands and forests. The carbon sequestration efficiency of grasslands, defined as the ratio of NBP to NPP, amounts to 0.09±0.10. Therefore, per unit of carbon input, grasslands sequester 3–4 times more carbon in the soil than forests do, making them a good candidate for managing onsite carbon sinks. When using the 100 yr greenhouse warming potential for CH4 and N2O, their emissions due to management of grasslands together offset roughly 70–80% of the carbon sink. Uncertainties on the European grassland

  2. Leaching and ponding of viral contaminants following land application of biosolids on sandy-loam soil.

    Science.gov (United States)

    Wong, Kelvin; Harrigan, Tim; Xagoraraki, Irene

    2012-12-15

    Much of the land available for application of biosolids is cropland near urban areas. Biosolids are often applied on hay or grassland during the growing season or on corn ground before planting or after harvest in the fall. In this study, mesophilic anaerobic digested (MAD) biosolids were applied at 56,000 L/ha on a sandy-loam soil over large containment lysimeters seeded to perennial covers of orchardgrass (Dactylis glomerata L.), switchgrass (Panicum virgatum), or planted annually to maize (Zea mays L.). Portable rainfall simulators were to maintain the lysimeters under a nearly saturated (90%, volumetric basis) conditions. Lysimeter leachate and surface ponded water samples were collected and analyzed for somatic phage, adenoviruses, and anionic (chloride) and microbial (P-22 bacteriophage) tracers. Neither adenovirus nor somatic phage was recovered from the leachate samples. P-22 bacteriophage was found in the leachate of three lysimeters (removal rates ranged from 1.8 to 3.2 log(10)/m). Although the peak of the anionic tracer breakthrough occurred at a similar pore volume in each lysimeter (around 0.3 pore volume) the peak of P-22 breakthrough varied between lysimeters (worm holes or other natural phenomena. The concentration of viral contaminants collected in ponded surface water ranged from 1 to 10% of the initial concentration in the applied biosolids. The die off of somatic phage and P-22 in the surface water was fit to a first order decay model and somatic phage reached background level at about day ten. In conclusion, sandy-loam soils can effectively remove/adsorb the indigenous viruses leached from the land-applied biosolids, but there is a potential of viral pollution from runoff following significant rainfall events when biosolids remain on the soil surface.

  3. Alpine grassland fPAR change over the Northern Tibetan Plateau from 2002 to 2011

    Directory of Open Access Journals (Sweden)

    Bao-Xiong Chen

    2017-06-01

    Full Text Available In this study, two different methods including Digital Camera and Reference Panel (DCRP and traditional in situ fPAR observation for measuring the in situ point fPAR of very short alpine grass vegetation were compared, and the Moderate Resolution Imaging Spectroradiometer (MODIS fPAR products were evaluated and validated by in situ point data on the alpine grassland over the Northern Tibetan Plateau, which is sensitive to climate change and vulnerable to anthropogenic activities. Results showed that the MODIS alpine grassland fPAR product, examined by using DCRP, and traditional in situ fPAR observation had a significant relationship at the spatial and temporal scales. The decadal MODIS fPAR trend analysis showed that, average growing season fPAR increased by 1.2 × 10−4 per year and in total increased 0.86% from 2002 to 2011 in alpine grassland, when most of the fPAR increments occurred in southeast and center of the Northern Tibetan Plateau, the alpine grassland tended to recover from degradation slightly. However, climatic factors have influenced the various alpine grassland vegetation fPAR over a period of 10 years; precipitation significantly affected the alpine meadow fPAR in the eastern region, whereas temperature considerably influenced the alpine desert steppe fPAR in the west region. These findings suggest that the regional heterogeneity in alpine grassland fPAR results from various environmental factors, except for vegetation characteristics, such as canopy structure and leaf area.

  4. Spectral identification of plant communities for mapping of semi-natural grasslands

    DEFF Research Database (Denmark)

    Jacobsen, Anne; Nielsen, Allan Aasbjerg; Ejrnæs, Rasmus

    2000-01-01

    The study was performed on Danish grasslands on well-drained sandy soils. Image data included georeferenced Compact Airborne Spectrographic Imager (casi) data calibrated to apparent surface reflectance. Ecological data included a field-based management map, registration of (vascular) plant species...... and thirty 30 m by 30 m test sites with affinities seven management classes identified in the field and seven floristic classes modelled from detrended correspondence analysis. Spectral analysis was performed on the derived image reflectance of 18 test sites positioned within the casi scanline. Spectral...... identification of plant communities was based on a hierarchical approach relating the test sites to i) management (Ma) and ii) flora (Fl) using spectral consistency and separability as the main criteria. Evaluation of spectral consistency was based on unsupervised clustering of test sites of Ma classes 1 to 7...

  5. Landscape Visual Quality and Meiofauna Biodiversity on Sandy Beaches

    Science.gov (United States)

    Felix, Gabriela; Marenzi, Rosemeri C.; Polette, Marcos; Netto, Sérgio A.

    2016-10-01

    Sandy beaches are central economic assets, attracting more recreational users than other coastal ecosystems. However, urbanization and landscape modification can compromise both the functional integrity and the attractiveness of beach ecosystems. Our study aimed at investigating the relationship between sandy beach artificialization and the landscape perception by the users, and between sandy beach visual attractiveness and biodiversity. We conducted visual and biodiversity assessments of urbanized and semiurbanized sandy beaches in Brazil and Uruguay. We specifically examined meiofauna as an indicator of biodiversity. We hypothesized that urbanization of sandy beaches results in a higher number of landscape detractors that negatively affect user evaluation, and that lower-rated beach units support lower levels of biodiversity. We found that urbanized beach units were rated lower than semiurbanized units, indicating that visual quality was sensitive to human interventions. Our expectations regarding the relationship between landscape perception and biodiversity were only partially met; only few structural and functional descriptors of meiofauna assemblages differed among classes of visual quality. However, lower-rated beach units exhibited signs of lower environmental quality, indicated by higher oligochaete densities and significant differences in meiofauna structure. We conclude that managing sandy beaches needs to advance beyond assessment of aesthetic parameters to also include the structure and function of beach ecosystems. Use of such supporting tools for managing sandy beaches is particularly important in view of sea level rise and increasing coastal development.

  6. Effect of Sheep Grazing Methods and Intensities on Recovering Forage Cell Wall Components and Nutritive Value of Degraded Grassland by Enclosed%绵羊放牧方式及强度对围封恢复草场牧草细胞壁成分及营养价值的影响

    Institute of Scientific and Technical Information of China (English)

    塔娜; 德庆哈拉; 那日苏

    2013-01-01

    选取内蒙古自治区典型草原区封育恢复中天然放牧草场,进行毛肉兼用细毛羊的暖季放牧试验.采用2×5完全随机试验设计,设定不同放牧方式(不放牧,连续放牧,四区、五区、六区轮牧)及2种放牧强度(1.0,1.4 hm2/un.sh),运用酶分析方法分析比较了围封过程中放牧绵羊对封育草场牧草细胞壁成分月动态变化及营养价值的影响.结果表明,整个暖季放牧期内,不同放牧区牧草营养物质含量主要受到放牧方式的显著影响(P<0.05).具体表现为,不放牧处理牧草细胞壁有机物(OCW)含量始终显著低于各放牧处理,不同放牧处理间没有明显差异;划区轮牧处理牧草始终保持着较高的消化性部分且显著高于连续放牧处理;不放牧处理牧草始终保持着较高的Oa和较低的Ob,而连续放牧处理与其相反,各轮牧处理间没有显著差异;轮牧处理总可消化养分(TDN)和代谢能(ME)含量较高,尤其在牧草生长旺盛期(八月份),六区轮牧放牧场牧草可利用营养物质含量最高,营养价值最高.%The sheep grazing experiment was carried out in an Inner Mongolian enclosed recovery steppe of the natural grazing pastures in warm season to study the dynamic changes of forage cell wall constituents and nutrients value with the chemical assay and enzymatic analysis.The comparison of grazing systems (control,continuous grazing,4 plots rotational grazing,5 plots rotational grazing,and 6 plots rotational grazing) was made at two levels of grazing intensities (1.0,1.4 hm2/un.sh) to create 10 treatments and 34 pairs of sheep (ewes and their lambs) were grazed over a period of 4 months.The results showed,in the whole warm season,forage nutrition contents in different grazing groups were mainly affected by grazing systems significantly on recovering degraded grassland (P<0.05).Forage OCW contents in control were significantly higher than those in continuous and rotational grazing

  7. 高寒退化草地狼毒种群地上生物量空间格局对地形的响应%Responses of the spatial pattern of Stellera chamaejasme's aboveground biomass to topography in degraded alpine grassland

    Institute of Scientific and Technical Information of China (English)

    侯兆疆; 赵成章; 李钰; 张茜; 马小丽

    2013-01-01

    地上生物量的空间格局是物种分布格局的重要内容,在小尺度范围内因地形差异导致的环境异质性是这种格局形成和演变的环境基础.在2011年8月野外调查的基础上,借助ArcGIS和S-PLUS软件,利用广义相加模型(GAM)对退化高寒草地狼毒(Stellera chamaejasme)种群的空间分布格局进行了研究,定量分析了狼毒地上生物量空间格局对主要地形因子的响应机制.结果表明:狼毒种群地上生物量受地形因子影响的顺序为坡向>坡度>海拔>平面曲率>剖面曲率;坡向和坡度两种地形因子对狼毒的地上生物量空间格局的贡献率分别为3.75和1.48,其余因子则相对较小;狼毒地上生物量在海拔、平面曲率和剖面曲率梯度上的分布比较均衡,在坡向梯度上呈开口向下的抛物线趋势,在坡度梯度上则呈现开口向上的抛物线趋势.狼毒地上生物量空间异质性及其与地形因子之间的关系,反映了狼毒在地形因子对水热条件重分配影响下的响应机制及生长策略.%The spatial pattern of aboveground biomass is an important content of species distribu-tion pattern, whereas the environmental heterogeneity caused by the topographical differences in the scope of small scales is the environmental basis for the formation and evolution of this pattern. Based on the field survey in August 2011 and with the help of GIS and S-PLUS software, the gen-eralized additive model ( GAM) was applied to study the spatial distribution pattern of S. chamaejasme population in degraded alpine grassland, and to quantitatively analyze the re-sponse mechanisms of the spatial pattern of S. chamaejasme' s aboveground biomass to topograph-ical factors. Topographical factors had definite effects on the aboveground biomass of S. chamae-jasme , with the sequence of aspect > slope > elevation > plane curvature > profile curvature. The contribution degree of aspect and slope to the spatial pattern of

  8. [Perspectives in researches on grassland ecology for the early 21st century in China].

    Science.gov (United States)

    Liang, Cunzhu; Zhu, Tingcheng; Wang, Deli; Lü, Xinlong

    2002-06-01

    Grassland degeneration is a prominent problem in China. More in-depth studies should be carried out on the key problem--grassland degeneration for Chinese grassland ecologists in the early 21st century. Some hot research fields were restoration ecology, interface ecology, grazing ecology, health diagnoses and evaluation for grasslands. Among them, restoration ecology was the foundation for restoring degenerative grasslands; interface ecology involved with the point of contact for analyzing degenerative grasslands; grazing ecology was the effective way to control degenerative grasslands; diagnoses of grassland health benefited accurately appraising degenerative levels of grasslands; and evaluation for grassland was also considered as an estimation on services and benefits of grassland ecosystems.

  9. Effects of freeze-thaw on soil nitrogen and phosphorus availability at the Keerqin Sandy Lands, China

    Institute of Scientific and Technical Information of China (English)

    ZHAO Qiong; ZENG De-hui; FAN Zhi-ping

    2008-01-01

    A laboratory simulated freeze-thaw was conducted to determine the effects of freeze-thaw on soil nutrient availability in temperate semi-arid regions. Soil samples were collected from sandy soils (0-20 cm) of three typical ecosystems (grassland, Mongolian pine plantation and poplar plantation) in southeastern Keerqin Sandy Lands of China and subjected to freeze-thaw treatment (-12℃ for 10 days, then 20℃ for 10 days) or incubated at constant temperature (20℃ for 20 days). Concentrations of the soil NO3--N, NH4+-N, NaHCO3 extractable inorganic P (LPi) and microbial biomass P (MBP) were determined on three occasions: at the start of the incubation, immediate post-thawing and at the 10th day post-thawing. The results showed that soil net nitrification and N mineralization rates at three sites were negatively affected by freeze-thaw treatment, and decreased by 50%-85% as compared to the control, of which the greatest decline occurred in the soil collected from poplar plantation. In contrast, the concentration of soil NH4+-N, NaHCO3 extractable inorganic P (LPi) and microbial biomass P were insignificantly influenced by freeze-thaw except that LPi and NH4+-N showed a slight increase immediate post-thawing. The effects of freeze-thaw on soil N transformation were related to soil biological processes and the relatively constant available P was ascribed to severe soil aridity.

  10. Some insights on grassland health assessment based on remote sensing.

    Science.gov (United States)

    Xu, Dandan; Guo, Xulin

    2015-01-29

    Grassland ecosystem is one of the largest ecosystems, which naturally occurs on all continents excluding Antarctica and provides both ecological and economic functions. The deterioration of natural grassland has been attracting many grassland researchers to monitor the grassland condition and dynamics for decades. Remote sensing techniques, which are advanced in dealing with the scale constraints of ecological research and provide temporal information, become a powerful approach of grassland ecosystem monitoring. So far, grassland health monitoring studies have mostly focused on different areas, for example, productivity evaluation, classification, vegetation dynamics, livestock carrying capacity, grazing intensity, natural disaster detecting, fire, climate change, coverage assessment and soil erosion. However, the grassland ecosystem is a complex system which is formed by soil, vegetation, wildlife and atmosphere. Thus, it is time to consider the grassland ecosystem as an entity synthetically and establish an integrated grassland health monitoring system to combine different aspects of the complex grassland ecosystem. In this review, current grassland health monitoring methods, including rangeland health assessment, ecosystem health assessment and grassland monitoring by remote sensing from different aspects, are discussed along with the future directions of grassland health assessment.

  11. Some Insights on Grassland Health Assessment Based on Remote Sensing

    Directory of Open Access Journals (Sweden)

    Dandan Xu

    2015-01-01

    Full Text Available Grassland ecosystem is one of the largest ecosystems, which naturally occurs on all continents excluding Antarctica and provides both ecological and economic functions. The deterioration of natural grassland has been attracting many grassland researchers to monitor the grassland condition and dynamics for decades. Remote sensing techniques, which are advanced in dealing with the scale constraints of ecological research and provide temporal information, become a powerful approach of grassland ecosystem monitoring. So far, grassland health monitoring studies have mostly focused on different areas, for example, productivity evaluation, classification, vegetation dynamics, livestock carrying capacity, grazing intensity, natural disaster detecting, fire, climate change, coverage assessment and soil erosion. However, the grassland ecosystem is a complex system which is formed by soil, vegetation, wildlife and atmosphere. Thus, it is time to consider the grassland ecosystem as an entity synthetically and establish an integrated grassland health monitoring system to combine different aspects of the complex grassland ecosystem. In this review, current grassland health monitoring methods, including rangeland health assessment, ecosystem health assessment and grassland monitoring by remote sensing from different aspects, are discussed along with the future directions of grassland health assessment.

  12. On the Impact Angle of Hurricane Sandy's New Jersey Landfall

    Science.gov (United States)

    Hall, Timothy M.; Sobel, Adam H.

    2013-01-01

    Hurricane Sandy's track crossed the New Jersey coastline at an angle closer to perpendicular than any previous hurricane in the historic record, one of the factors contributing to recordsetting peak-water levels in parts of New Jersey and New York. To estimate the occurrence rate of Sandy-like tracks, we use a stochastic model built on historical hurricane data from the entire North Atlantic to generate a large sample of synthetic hurricanes. From this synthetic set we calculate that under long-term average climate conditions, a hurricane of Sandy's intensity or greater (category 1+) makes NJ landfall at an angle at least as close to perpendicular as Sandy's at an average annual rate of 0.0014 yr-1 (95% confidence range 0.0007 to 0.0023); i.e., a return period of 714 years (95% confidence range 435 to 1429).

  13. 2014 USGS CMGP Lidar: Post Sandy (Long Island, NY)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — TASK NAME: Long Island New York Sandy LIDAR lidar Data Acquisition and Processing Production Task USGS Contract No. G10PC00057 Task Order No. G14PD00296 Woolpert...

  14. Hurricane Sandy: Rapid Response Imagery of the Surrounding Regions

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The imagery posted on this site is of Hurricane Sandy. The aerial photography missions were conducted by the NOAA Remote Sensing Division. The images were acquired...

  15. 2008 USDA Forest Service Lidar: Sandy River Study Area

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Watershed Sciences, Inc. collected Light Detection and Ranging (LiDAR) data for the Sandy River study area in collaboration with the USDA Forest Service. The areas...

  16. James J. Howard Marine Sciences Laboratory @ Sandy Hook

    Data.gov (United States)

    Federal Laboratory Consortium — The James J. Howard Marine Sciences Laboratory, located on the New Jersey shore at Sandy Hook, is a state-of-the-art marine research facility shared by the National...

  17. Studies on Thiobacilli spp. isolated from sandy beaches of Kerala

    Digital Repository Service at National Institute of Oceanography (India)

    Gore, P.S.; Raveendran, O.; Unnithan, R.V.

    Occurrence, isolation and oxidative activity of Thiobacilli spp. from some sandy beaches of Kerala are reported. These organisms were encountered in polluted beaches and were dominant during monsoon in all the beaches...

  18. James J. Howard Marine Sciences Laboratory @ Sandy Hook

    Data.gov (United States)

    Federal Laboratory Consortium — The James J. Howard Marine Sciences Laboratory, located on the New Jersey shore at Sandy Hook, is a state-of-the-art marine research facility shared by the National...

  19. 2014 USGS CMGP Lidar: Sandy Restoration (Delaware and Maryland)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Geographic Extent: SANDY_Restoration_DE_MD_QL2 Area of Interest covers approximately 3.096 square miles. Lot #5 contains the full project area Dataset Description:...

  20. Short Communication Energy and ash contents of sandy beach ...

    African Journals Online (AJOL)

    macrofauna found on three exposed sandy beaches on the west coast ... that they often form the predominant shore type (Bally,. McQuaid ... their sediments are given in Table I. Animals ..... The biochemical composition of the tropical intertida1 ...

  1. Effects of shrub encroachment on soil organic carbon in global grasslands

    Science.gov (United States)

    Li, He; Shen, Haihua; Chen, Leiyi; Liu, Taoyu; Hu, Huifeng; Zhao, Xia; Zhou, Luhong; Zhang, Pujin; Fang, Jingyun

    2016-07-01

    This study aimed to evaluate the effect of shrub encroachment on soil organic carbon (SOC) content at broad scales and its controls. We conducted a meta-analysis using paired control data of shrub-encroached grassland (SEG) vs. non-SEG collected from 142 studies worldwide. SOC contents (0–50 cm) were altered by shrub encroachment, with changes ranging from ‑50% to + 300%, with an effect size of 0.15 (p legumes. The SOC content decreased in silty and clay soils but increased in sand, sandy loam and sandy clay loam. The SOC content increment was significantly positively correlated with precipitation and temperature as well as with soil bulk density but significantly negatively correlated with soil total nitrogen. We conclude the main effects of shrub encroachment would be to increase topsoil organic carbon content. As structural equation model revealed, soils properties seem to be the primary factors responsible for the extent of the changes, coarse textured soils having a greater capacity than fine textured soils to increase the SOC content. This increased effect appears to be secondarily enhanced by climate and plant elements.

  2. High potential of sub-Mediterranean dry grasslands for sheep epizoochory

    Directory of Open Access Journals (Sweden)

    Kaligarič Mitja

    2016-01-01

    Full Text Available There is a general decline of grasslands across Europe due to habitat loss and degradation. Ensuring plant dispersal thus becomes a key process for preserving grassland patches in all scales. We examined diaspore dispersal by sheep epizoochory in the pastures of the North Adriatic Karst (NW Slovenia and determined the qualitative and quantitative features of diaspores in fur. We recorded 25,650 diaspores of 141 plant taxa (with 107 taxa and 23,350 diaspores determined to species level, using three different methods: (i the “whole-coat method”, (ii the “part-of-thecoat method” and (iii a “seedling emergence method”. A comparison of these techniques revealed that the “wholecoat method” provided the highest number of diaspores and plant species. All diaspores were clustered into five emergent groups based on seven functional traits (diaspore weight, length, width, height, volume, specific weight and the diaspore surface structure. Our research revealed that sheep represent an important dispersal vector, since about half of the plant species recorded in the pastures were found as diaspores in fur. This study contributes to knowledge about the modes of seed dispersal in seminatural grasslands. Taking into account that livestock play a key role in vegetation dynamics, understanding their effects on seed dispersal is essential for conservation and restoration of these species-rich grassland communities.

  3. Impacts of atmospheric pollution on the plant communities of British acid grasslands

    Energy Technology Data Exchange (ETDEWEB)

    Payne, Richard J., E-mail: r.payne@mmu.ac.uk [School of Science and the Environment, Manchester Metropolitan University, Chester St., Manchester M1 5GD (United Kingdom); Geography, School of Environment and Development, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Stevens, Carly J. [Faculty of Science, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Lancaster Environment Centre, Lancaster University, Bailrigg, Lancaster LA1 4YQ (United Kingdom); Dise, Nancy B. [School of Science and the Environment, Manchester Metropolitan University, Chester St., Manchester M1 5GD (United Kingdom); Gowing, David J. [Faculty of Science, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Pilkington, Michael G.; Phoenix, Gareth K. [Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Sheffield S10 2TN (United Kingdom); Emmett, Bridget A. [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Ashmore, Michael R. [Environment Department, University of York, Heslington, York YO10 5DD (United Kingdom)

    2011-10-15

    Air pollutants are recognised as important agents of ecosystem change but few studies consider the effects of multiple pollutants and their interactions. Here we use ordination, constrained cluster analysis and indicator value analyses to identify potential environmental controls on species composition, ecological groupings and indicator species in a gradient study of UK acid grasslands. The community composition of these grasslands is related to climate, grazing, ozone exposure and nitrogen deposition, with evidence for an interaction between the ecological impacts of base cation and nitrogen deposition. Ozone is a key agent in species compositional change but is not associated with a reduction in species richness or diversity indices, showing the subtly different drivers on these two aspects of ecosystem degradation. Our results demonstrate the effects of multiple interacting pollutants, which may collectively have a greater impact than any individual agent. - Highlights: > Ozone exposure, N and base cation deposition modify UK acid grassland composition. > Ozone influences community composition without reducing species richness. > Nitrogen and base cation deposition have interacting impacts. > Distinct species responses to pollutants suggest potential for bioindication. - Ozone exposure and nitrogen deposition have distinct but additive impacts on the plant communities of British acid grasslands.

  4. Importance and functions of European grasslands.

    Science.gov (United States)

    Carlier, L; De Vliegher, A; Van Cleemput, O; Boeckx, P

    2005-01-01

    The European agricultural policy is not simple and needs to accommodate also social and environmental requirements. Grassland will continue to be an important form of land use in Europe, but with increased diversity in management objectives and systems used. Besides its role as basic nutrient for herbivores and ruminants grasslands have opportunities for adding value by exploiting positive health characteristics in animal products from grassland and through the delivery of environmental benefits. In fact grasslands contribute to a high degree to the struggle against erosion and to the regularizing of water regimes, to the purification of fertilizers and pesticides and to biodiversity. Finally they have aesthetic role and recreational function as far as they provide public access that other agricultural uses do not allow. But even for grassland it is very difficult to create a good frame for its different tasks (1) the provision of forage for livestock, (2) protection and conservation of soil and water resources, (3) furnishing a habitat for wildlife, both flora and fauna and (4) contribution to the attractiveness of the landscape. Nevertheless it is the only crop, able to fulfil so many tasks and to fit so many requirements.

  5. Madagascar's grasses and grasslands: anthropogenic or natural?

    Science.gov (United States)

    Vorontsova, Maria S; Besnard, Guillaume; Forest, Félix; Malakasi, Panagiota; Moat, Justin; Clayton, W Derek; Ficinski, Paweł; Savva, George M; Nanjarisoa, Olinirina P; Razanatsoa, Jacqueline; Randriatsara, Fetra O; Kimeu, John M; Luke, W R Quentin; Kayombo, Canisius; Linder, H Peter

    2016-01-27

    Grasses, by their high productivity even under very low pCO2, their ability to survive repeated burning and to tolerate long dry seasons, have transformed the terrestrial biomes in the Neogene and Quaternary. The expansion of grasslands at the cost of biodiverse forest biomes in Madagascar is often postulated as a consequence of the Holocene settlement of the island by humans. However, we show that the Malagasy grass flora has many indications of being ancient with a long local evolutionary history, much predating the Holocene arrival of humans. First, the level of endemism in the Madagascar grass flora is well above the global average for large islands. Second, a survey of many of the more diverse areas indicates that there is a very high spatial and ecological turnover in the grass flora, indicating a high degree of niche specialization. We also find some evidence that there are both recently disturbed and natural stable grasslands: phylogenetic community assembly indicates that recently severely disturbed grasslands are phylogenetically clustered, whereas more undisturbed grasslands tend to be phylogenetically more evenly distributed. From this evidence, it is likely that grass communities existed in Madagascar long before human arrival and so were determined by climate, natural grazing and other natural factors. Humans introduced zebu cattle farming and increased fire frequency, and may have triggered an expansion of the grasslands. Grasses probably played the same role in the modification of the Malagasy environments as elsewhere in the tropics.

  6. [Research progress and trend on grassland agroecology].

    Science.gov (United States)

    Ren, Jizhou; Li, Xianglin; Hou, Fujiang

    2002-08-01

    The connotation, progress, research frontiers and developmental trend of grassland agroecology are discussed in this paper. The interface theory, structure and function, coupling and discordance, and health assessment of grassland agroecosystems were recognized as the four research frontiers of the discipline. There exist three primary interfaces in a grassland agroecosystem, i.e., vegetation-site, grassland-animal and production-management. Research into a series of the ecological processes that occurred at these interfaces is the key to revealing the features of the system behavior. There are four sections in a grassland agroecosystem, i.e., pre-plant, plant, animal and post-biotic sections. System coupling and discordance are the two important concepts to describe interactions among the production sections. System coupling among the sections can lead to system improvement by exerting the potential of system capacity. Health of an ecosystem is a reflection of its structure and function, and health assessment is a measurement of its orderliness and service value.

  7. Regional variability in bed-sediment concentrations of wastewater compounds, hormones and PAHs for portions of coastal New York and New Jersey impacted by hurricane Sandy

    Science.gov (United States)

    Phillips, Patrick; Gibson, Cathy A; Fisher, Shawn C.; Fisher, Irene; Reilly, Timothy J.; Smalling, Kelly L.; Romanok, Kristin M.; Foreman, William T.; ReVello, Rhiannon C.; Focazio, Michael J.; Jones, Daniel K.

    2016-01-01

    Bed sediment samples from 79 coastal New York and New Jersey, USA sites were analyzed for 75 compounds including wastewater associated contaminants, PAHs, and other organic compounds to assess the post-Hurricane Sandy distribution of organic contaminants among six regions. These results provide the first assessment of wastewater compounds, hormones, and PAHs in bed sediment for this region. Concentrations of most wastewater contaminants and PAHs were highest in the most developed region (Upper Harbor/Newark Bay, UHNB) and reflected the wastewater inputs to this area. Although the lack of pre-Hurricane Sandy data for most of these compounds make it impossible to assess the effect of the storm on wastewater contaminant concentrations, PAH concentrations in the UHNB region reflect pre-Hurricane Sandy conditions in this region. Lower hormone concentrations than predicted by the total organic carbon relation occurred in UHNB samples, suggesting that hormones are being degraded in the UHNB region.

  8. Grassland Management Plan Union Slough National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Northern Tallgrass Prairie is an endangered ecosystem, and in turn, grassland dependent birds and some forbs are in serious peril. The Grassland Management Plan...

  9. Grassland Management Plan : Swan Lake National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Grassland Management Plan for Swan Lake National Wildlife Refuge provides an overview of the Refuge, a list of special considerations affecting grassland...

  10. Grassland Management Plan: Union Slough National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The plan outlines grassland habitat management objectives for Union Slough National Wildilfe Refuge. The Grassland Management Plan objectives include; preserve...

  11. Management of grasslands 1996 : Bear River Migratory Bird Refuge [Draft

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document is a summary of grassland management for Bear River Migratory Bird Refuge in Utah, which has recently began acquiring new grassland habitat that will...

  12. 2009 Field Season : Annual Grassland Vegetation Monitoring : Summary

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — An annual grassland monitoring plan was initiated on the grassland units at Bear River Migratory Bird Refuge during the 2009 field season. The annual monitoring plan...

  13. Do grasslands act as a perpetual sink for carbon?

    Science.gov (United States)

    Smith, Pete

    2014-09-01

    It is increasingly commonly suggested that grasslands are a perpetual sink for carbon, and that just maintaining grasslands will yield a net carbon sink. I examine the evidence for this from repeated soil surveys, long term grassland experiments and simple mass balance calculations. I conclude that it is untenable that grasslands act as a perpetual carbon sink, and the most likely explanation for observed grassland carbon sinks over short periods is legacy effects of land use and land management prior to the beginning of flux measurement periods. Simply having grassland does not result is a carbon sink, but judicious management or previously poorly managed grasslands can increase the sink capacity. Given that grasslands are a large store of carbon, and that it is easier and faster for soils to lose carbon that it is for them to gain carbon, it is an important management target to maintain these stocks.

  14. EAARL-B Coastal Topography--Eastern New Jersey, Hurricane Sandy, 2012: First Surface, Pre-Sandy

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — ASCII xyz and binary point-cloud data, as well as a digital elevation model (DEM) of a portion of the New Jersey coastline, pre- and post-Hurricane Sandy (October...

  15. Bird communities and biomass yields in potential bioenergy grasslands.

    Directory of Open Access Journals (Sweden)

    Peter J Blank

    Full Text Available Demand for bioenergy is increasing, but the ecological consequences of bioenergy crop production on working lands remain unresolved. Corn is currently a dominant bioenergy crop, but perennial grasslands could produce renewable bioenergy resources and enhance biodiversity. Grassland bird populations have declined in recent decades and may particularly benefit from perennial grasslands grown for bioenergy. We asked how breeding bird community assemblages, vegetation characteristics, and biomass yields varied among three types of potential bioenergy grassland fields (grass monocultures, grass-dominated fields, and forb-dominated fields, and assessed tradeoffs between grassland biomass production and bird habitat. We also compared the bird communities in grassland fields to nearby cornfields. Cornfields had few birds compared to perennial grassland fields. Ten bird Species of Greatest Conservation Need (SGCN were observed in perennial grassland fields. Bird species richness and total bird density increased with forb cover and were greater in forb-dominated fields than grass monocultures. SGCN density declined with increasing vertical vegetation density, indicating that tall, dense grassland fields managed for maximum biomass yield would be of lesser value to imperiled grassland bird species. The proportion of grassland habitat within 1 km of study sites was positively associated with bird species richness and the density of total birds and SGCNs, suggesting that grassland bioenergy fields may be more beneficial for grassland birds if they are established near other grassland parcels. Predicted total bird density peaked below maximum biomass yields and predicted SGCN density was negatively related to biomass yields. Our results indicate that perennial grassland fields could produce bioenergy feedstocks while providing bird habitat. Bioenergy grasslands promote agricultural multifunctionality and conservation of biodiversity in working landscapes.

  16. Bird communities and biomass yields in potential bioenergy grasslands.

    Science.gov (United States)

    Blank, Peter J; Sample, David W; Williams, Carol L; Turner, Monica G

    2014-01-01

    Demand for bioenergy is increasing, but the ecological consequences of bioenergy crop production on working lands remain unresolved. Corn is currently a dominant bioenergy crop, but perennial grasslands could produce renewable bioenergy resources and enhance biodiversity. Grassland bird populations have declined in recent decades and may particularly benefit from perennial grasslands grown for bioenergy. We asked how breeding bird community assemblages, vegetation characteristics, and biomass yields varied among three types of potential bioenergy grassland fields (grass monocultures, grass-dominated fields, and forb-dominated fields), and assessed tradeoffs between grassland biomass production and bird habitat. We also compared the bird communities in grassland fields to nearby cornfields. Cornfields had few birds compared to perennial grassland fields. Ten bird Species of Greatest Conservation Need (SGCN) were observed in perennial grassland fields. Bird species richness and total bird density increased with forb cover and were greater in forb-dominated fields than grass monocultures. SGCN density declined with increasing vertical vegetation density, indicating that tall, dense grassland fields managed for maximum biomass yield would be of lesser value to imperiled grassland bird species. The proportion of grassland habitat within 1 km of study sites was positively associated with bird species richness and the density of total birds and SGCNs, suggesting that grassland bioenergy fields may be more beneficial for grassland birds if they are established near other grassland parcels. Predicted total bird density peaked below maximum biomass yields and predicted SGCN density was negatively related to biomass yields. Our results indicate that perennial grassland fields could produce bioenergy feedstocks while providing bird habitat. Bioenergy grasslands promote agricultural multifunctionality and conservation of biodiversity in working landscapes.

  17. Grassland birds: An overview of threats and recommended management strategies

    Science.gov (United States)

    Vickery, P.D.; Herkert, J.R.; Knopf, F.L.; Ruth, J.; Keller, C.E.; Bonney, Rick; Pashley, David N.; Cooper, Robert; Niles, Larry

    2000-01-01

    Grassland ecosystems are dependent on periodic disturbance for habitat maintenance. Historically, grazing by native herbivores and prairie fires were the agents principally responsible for maintaining grassland areas. However, elimination of native herbivores, wide-spread fire suppression, and conversion for agriculture have greatly altered grasslands in the United States and Canada. Because of these landscape changes, many grassland birds are increasingly dependent on land managers for habitat creation, maintenance, and health. Grazing, prescribed burning, and mowing/haying are the most frequently used, and versatile, grassland management techniques. Grassland birds prefer a wide range of grass heights and densities, with some species preferring short sparse vegetation, and others preferring taller, more dense vegetation. Due to differences in species habitat preferences and regional differences in soils and floristics, the responses of individual grassland species to specific grassland management practices can be variable and often are regionally dependent. As a result, management of grassland areas is best directed toward the creation of a mosaic of grassland habitat types. This habitat mosaic is probably best maintained through some type of rotational management system in which sections of large grassland areas receive management on a regular schedule. Such a rotational system would provide a variety of habitat types in every year, would ensure the availability of suitable habitat for birds at either end of the grassland management spectrum, and also would provide habitat for birds whose preferences lie between these extremes.

  18. Research Advance on Carbon Storage of Artificial Grassland in China

    Institute of Scientific and Technical Information of China (English)

    Fuping; TIAN; Yongjie; SHI; Yu; HU; Zixuan; CHEN; Yuan; LU; Xiaofu; ZHANG; Runlin; LI

    2013-01-01

    As an essential part of the grassland ecological system,study on the carbon storage has great significances to the carbon reduction in grassland ecological system.The carbon storage in biomass,carbon storage in soil and soil respiration are summarized in this paper to provide scientific reference for the evaluation of carbon storage in artificial grassland.

  19. Negative global phosphorus budgets challenge sustainable intensification of grasslands

    NARCIS (Netherlands)

    Sattari, S.Z.; Bouwman, A.F.; Martinez Rodríguez, R.; Beusen, A.H.W.; Ittersum, Van M.K.

    2016-01-01

    Grasslands provide grass and fodder to sustain the growing need for ruminant meat and milk. Soil nutrients in grasslands are removed through withdrawal in these livestock products and through animal manure that originates from grasslands and is spread in croplands. This leads to loss of soil fert

  20. Grassland ecology and diversity (Ecologia y diversidad de pastizales)

    Science.gov (United States)

    Laurie B. Abbott

    2006-01-01

    Grasslands of the Chihuahuan Desert region are ecologically and economically important. These grasslands are valued for their rangeland, wildlife, watershed, and recreation resources. Biological diversity also raises the value of grassland communities. The potential for multiple uses within the region increases as the diversity of the resource base increases. In order...

  1. Grassland bats and land management in the Southwest

    Science.gov (United States)

    Alice L. Chung-MacCoubrey

    1996-01-01

    Of the bat research that has been conducted in the Southwestern states, few studies have addressed species inhabiting grasslands and the potential effects of management activities on these populations. Up to 17 bat species may be found regularly or occasionally in Southwestern grasslands or short-grass prairie. Main habitat requirements of grassland-dwelling bats are...

  2. Soil acidification and liming in grassland production and grassland soil fertility in Slovenia

    Directory of Open Access Journals (Sweden)

    Jure ČOP

    2015-12-01

    Full Text Available This paper reviews the evidences on grassland soil acidity and liming in relation to soil processes and herbage production. There is also an outline of the present state of soil acidity and acidity-related traits – contents of organic matter (OM, phosphorus (P and potassium (K in Slovene grassland. In grassland, soil acidification is an ongoing process under humid climate conditions. It is mainly driven by leaching of nutrients, net loss of cations due to retention in livestock products, use of physiologically acid fertilizers, acid rain and N2 fixation. This process is reduced by strong pH buffering capacity of the soil and by physiologically basic fertilizers. Acid grassland soils in Slovenia are widely distributed in spite of the fact that 44% of the total land has developed from a carbonate parent material. Of the 1713 grassland soil samples analysed during 2005-2007 45% were regarded as acid ones (pH < 5.5; in KCl, 57% as soils with very low P status (˂ 6 mg P2O5/100 g soil and 22% as soils with very low K status (˂ 10 mg K2O/100 soil. Increased content of soil organic matter was identified for alpine pastures (˃ 10 % OM in 44% of samples, mainly as a result of low decomposition rate. Liming of acid grassland soils did not always reflect in a higher herbage yield. The cause for this inefficiency is plant composition of grassland. Thus, many grassland plants with relatively high production potential have adapted to acid soil conditions. To illustrate the inconsistent liming effect three researches are reviewed. In the first two researches liming along with fertilizer application did not increase the yield comparing to the fertilized control while in the third research the increase amounted 26 %. Liming improves considerably botanical composition of the acid grassland (e.g. sward where Common Bent – Agrostis tenuis Sibth. – prevails and thus indirectly affects palatability and nutritive value of herbage. Grassland liming has a weak

  3. Vegetation of the Sileza Nature Reserve and neighbouring areas, South Africa, and its importance in conserving the woody grasslands of the Maputaland Centre of Endemism

    Directory of Open Access Journals (Sweden)

    W. S. Matthews

    1999-12-01

    Full Text Available An analysis of the plant communities of the Sileza Nature Reserve and surrounding areas (± 4 124 ha is presented. The study area falls within the Maputaland Centre o f Endemism, which is part ot the Maputaland-Pondoland Region, a centre of plant diversity rich in endemic plants and animals. A TWINSPAN classification, refined by Braun-Blanquet procedures, revealed 12 distinct, mainly grassland plant communities. A hierarchical classification, description and ecological interpretation ot these communities are presented. The level o f the water table, either directly, or indirectly through its role in soil formation, is the deciding factor in defining plant communities on the geologically young sandy substrate. Fire is an essential factor, particularly in maintaining the woody grasslands, a rare vegetation type rich in geoxylic suffrutices. and unique to the Maputaland Centre. A comparison between the endemic complement in the subtropical coastal grasslands of Maputaland and the high-altitude Afromontane grasslands of the Wolkberg Centre of Endemism shows marked differences in grow th form and vegetation type partitioning between the two centres. This can probably be ascribed to the relative youth (Quaternary of the Maputaland coastal plain and its associated plant communities. Notable for their richness in Maputaland Centre endemic/near-endemic taxa. the conservation of sand forest and woody grasslands should receive high priority. Afforestation with alien trees is the most serious threat to the biodiversity of the Maputaland coastal grasslands, not only because of habitat destruction, but also through its expected negative effect on the hydrology of the region

  4. Energetic Potential of Romania’s Grasslands

    Directory of Open Access Journals (Sweden)

    Neculai Dragomir

    2012-05-01

    Full Text Available Permanent grasslands represent, all over the world, an asset that contributes to maintaining ecological balance in all other natural ecosystem, a never-ending reservoir of vegetal biomass that supplies most of the necessary food for animals and that can also be an important source of “green energy”. In Romania, only 56% of the grassland area (i.e. 2,200,000 ha would be enough to cover the necessary fibrous fodder for the cattle, while the rest of 44% (i.e. 1,700,000 ha could be used to produce energy.

  5. COENOLOGICAL SHIFT FOLLOWING FERTILIZATION IN MEDITERRANEAN GRASSLAND

    Directory of Open Access Journals (Sweden)

    ALESSANDRO SERAFINI SAULI

    2006-05-01

    Full Text Available In Rome both meadows of CentraI-European affinity and Mediterranean dry grasslands are presento We studied a site (Parco Regionale Urbano de] Pineto in Rome with very diverse vegetation, where species belonging to both coenologica] groups oceur. Wc fertilized a grassland with a combination of phosphorus (P and nitrogen (N. After fertilization diagDostie species of Helianthemetea guttati (Thcrophytes dccrease while species of MolinioArrhenatheretea (Hemicriptophytes increase. In a climate as that of Rome, transition between Mediterranean (with summer drought and Central European (without summer drought, nutrients availability modulates the distribution of vegetation Classes with respectively Mediterranean or Central-Europe affinities.

  6. Brazilian sandy beach macrofauna production: a review

    Directory of Open Access Journals (Sweden)

    Marcelo Petracco

    2012-12-01

    Full Text Available The state of the art of the studies on the production of Brazilian sandy beach macrofauna was analyzed on the basis of the data available in the literature. For this purpose, the representativeness of the production dataset was examined by latitudinal distribution, degree of exposure and morphodynamic state of beaches, taxonomic groups, and methods employed. A descriptive analysis was, further, made to investigate the trends in production of the more representative taxonomic groups and species of sandy beach macrofauna. A total of 69 macrofauna annual production estimates were obtained for 38 populations from 25 studies carried out between 22º56'S and 32º20'S. Production estimates were restricted to populations on beaches located on the southern and southeastern Brazilian coast. Most of the populations in the dataset inhabit exposed dissipative sandy beaches and are mainly represented by mollusks and crustaceans, with a smaller number of polychaetes. The trends in production among taxonomic groups follow a similar pattern to that observed on beaches throughout the world, with high values for bivalves and decapods. The high turnover rate (P/B ratio of the latter was due to the presence of several populations of the mole crab Emerita brasiliensis, which can attain high values of productivity, in the dataset. Most of the studies focus on the comparison of production and, especially, of P/B ratio according to life history traits in populations of the same species/taxonomic group. Despite the importance of life history-production studies, other approaches, such as the effect of man-induce disturbances on the macrofauna, should be undertaken in these threatened environments.O estado da arte dos estudos de produção da macrofauna de praias arenosas brasileiras foi analisado a partir de informações disponíveis na literatura. Para essa finalidade, a representatividade dos dados de produção foi examinada de acordo com a distribuição latitudinal

  7. The Relationship Between Soil Organic Carbon and Nitrogen Distribution and Community Biomass in the Process of Grassland Degradation%草原退化过程中土壤碳氮分布与群落生物量的关系

    Institute of Scientific and Technical Information of China (English)

    王雪婷; 乌云娜; 王洋; 李阳; 李双池; 李博思

    2014-01-01

    For effective development and utilization of grassland ,maintenance of grassland ecosystem virtuous circle ,taking the Hulunbeir Kerulen's esparto(Stipa krylovii)typical grassland in Inner Mongolia as research object ,setting up different grazing gradients of natural grassland test sample plot and using the methods of field investigation and indoor analysis ,different grazing intensity of soil carbon -nitrogen space step pattern and its influence on vegetation productivity were studied .The results showed that the plant biomass changed with the trend of lightly grazed> moderately grazed> heavily grazed in different grazing gradients ;Soil organic carbon content had obvious difference :lightly grazed> heavily grazed> moderately grazed ;Soil nitrogen content had obvious differences between various samples in different grazing gradients :lightly grazed> heavily grazed and lightly grazed>moderately grazed ,the relationship between moderately grazed and heavily grazed was not obvi-ous ;soil C/N value and plant biomass all maintained a relatively stable relation in different grazing gradients .%为了有效开发利用草原、维护草原生态系统良性循环,以内蒙古呼伦贝尔克鲁伦流域的克氏针茅(Stipa krylovii)典型草原为研究对象,通过设置不同放牧强度的天然草原试验样地,采用野外实地调查与室内分析法,研究不同放牧强度下土壤碳-氮空间分布格局以及其对植被生产力的影响。结果表明:不同放牧梯度上植物地上生物量变化趋势为:轻牧>中牧>重牧;不同放牧梯度上的土壤有机质碳含量有显著差异性,变化表现为:轻牧>重牧>中牧;不同放牧梯度上的土壤氮含量有显著差异性,且轻牧>重牧、轻牧>中牧,中牧、重牧变化关系不显著;不同放牧梯度上,土壤C/N值与植物生物量均保持一种相对稳定的关系。

  8. Impacts of atmospheric pollution on the plant communities of British acid grasslands.

    Science.gov (United States)

    Payne, Richard J; Stevens, Carly J; Dise, Nancy B; Gowing, David J; Pilkington, Michael G; Phoenix, Gareth K; Emmett, Bridget A; Ashmore, Michael R

    2011-10-01

    Air pollutants are recognised as important agents of ecosystem change but few studies consider the effects of multiple pollutants and their interactions. Here we use ordination, constrained cluster analysis and indicator value analyses to identify potential environmental controls on species composition, ecological groupings and indicator species in a gradient study of UK acid grasslands. The community composition of these grasslands is related to climate, grazing, ozone exposure and nitrogen deposition, with evidence for an interaction between the ecological impacts of base cation and nitrogen deposition. Ozone is a key agent in species compositional change but is not associated with a reduction in species richness or diversity indices, showing the subtly different drivers on these two aspects of ecosystem degradation. Our results demonstrate the effects of multiple interacting pollutants, which may collectively have a greater impact than any individual agent.

  9. Sandy River Delta Habitat Restoration Project, Annual Report 2001.

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Virginia; Dobson, Robin L.

    2002-11-01

    The Sandy River Delta is located at the confluence of the Sandy and Columbia Rivers, just east of Troutdale, Oregon. It comprises about 1,400 land acres north of Interstate 84, managed by the USDA Forest Service, and associated river banks managed by the Oregon Division of State Lands. Three islands, Gary, Flag and Catham, managed by Metro Greenspaces and the State of Oregon lie to the east, the Columbia River lies to the north and east, and the urbanized Portland metropolitan area lies to the west across the Sandy River. Sandy River Delta was historically a wooded, riparian wetland with components of ponds, sloughs, bottomland woodland, oak woodland, prairie, and low and high elevation floodplain. It has been greatly altered by past agricultural practices and the Columbia River hydropower system. Restoration of historic landscape components is a primary goal for this land. The Forest Service is currently focusing on restoration of riparian forest and wetlands. Restoration of open upland areas (meadow/prairie) would follow substantial completion of the riparian and wetland restoration. The Sandy River Delta is a former pasture infested with reed canary grass, blackberry and thistle. The limited over story is native riparian species such as cottonwood and ash. The shrub and herbaceous layers are almost entirely non-native, invasive species. Native species have a difficult time naturally regenerating in the thick, competing reed canary grass, Himalayan blackberry and thistle. A system of drainage ditches installed by past owners drains water from historic wetlands. The original channel of the Sandy River was diked in the 1930's, and the river diverted into the ''Little Sandy River''. The original Sandy River channel has subsequently filled in and largely become a slough. The FS acquired approximately 1,400 acres Sandy River Delta (SRD) in 1991 from Reynolds Aluminum (via the Trust for Public Lands). The Delta had been grazed for many years

  10. Hurricane Sandy Washover Deposits on Southern Long Beach Island, NJ

    Science.gov (United States)

    Bishop, J. M.; Richmond, B. M.; Kane, H. H.; Lunghino, B.

    2015-12-01

    Hurricane Sandy washover deposits were investigated at Forsyth National Wildlife Refuge (FNWR) on Southern Long Beach Island, New Jersey in order to map deposit thickness and characterize the sedimentary deposits. FNWR was chosen as a field area because there has been relatively little anthropogenic shoreline modification since washover deposition from Hurricane Sandy. Sediment, elevation, and geophysical data were collected during the April 2015 field campaign, approximately two and a half years after the storm. Sediment deposit data included trenches, stratigraphic descriptions, bulk sediment samples, push cores, Russian cores, and photos. Computed tomography (CT) scanning was conducted on push cores in order to acquire high resolution imaging of density, grain size, and sedimentary structure. Profiles of washover elevation were measured using Differential GPS with Real Time Kinematic processing. Ground Penetrating Radar data was collected to image the depth of the deposit and identify sedimentary structures. These data sets are compared to pre- and post -Sandy lidar surveys in order to determine post-Sandy modification in the two and a half years following the hurricane. We compare sediment thickness and sedimentary characteristics to hurricane Sandy deposits elsewhere along the U.S. eastern seaboard and to tsunami deposits.

  11. Earthworm communities in grasslands and horticultural soils

    NARCIS (Netherlands)

    Didden, W.A.M.

    2001-01-01

    In a survey of 42 farm sites, comprising grassland and two types of horticultural farms (growing vegetables or flower bulbs), earthworm communities were sampled by hand-sorting and a number of soil physico-chemical characteristics recorded. For heavy metals the availability in the soil solution was

  12. Evolution of Grasses and Grassland Ecosystems

    Science.gov (United States)

    Strömberg, Caroline A. E.

    2011-05-01

    The evolution and subsequent ecological expansion of grasses (Poaceae) since the Late Cretaceous have resulted in the establishment of one of Earth's dominant biomes, the temperate and tropical grasslands, at the expense of forests. In the past decades, several new approaches have been applied to the fossil record of grasses to elucidate the patterns and processes of this ecosystem transformation. The data indicate that the development of grassland ecosystems on most continents was a multistage process involving the Paleogene appearance of (C3 and C4) open-habitat grasses, the mid-late Cenozoic spread of C3 grass-dominated habitats, and, finally, the Late Neogene expansion of C4 grasses at tropical-subtropical latitudes. The evolution of herbivores adapted to grasslands did not necessarily coincide with the spread of open-habitat grasses. In addition, the timing of these evolutionary and ecological events varied between regions. Consequently, region-by-region investigations using both direct (plant fossils) and indirect (e.g., stable carbon isotopes, faunas) evidence are required for a full understanding of the tempo and mode of grass and grassland evolution.

  13. On the stability of mixed grasslands

    NARCIS (Netherlands)

    Schulte, R.P.O.

    2001-01-01

    Recent years have seen a renewed interest in the use of white clover (Trifolium repens) in grasslands, as a more sustainable alternative to fertiliser nitrogen inputs. However, mixtures of grasses and white clover have frequently been associated with unstable and hence unreliable herbage yields. The

  14. On the stability of mixed grasslands

    NARCIS (Netherlands)

    Schulte, R.P.O.

    2001-01-01

    Recent years have seen a renewed interest in the use of white clover (Trifolium repens) in grasslands, as a more sustainable alternative to fertiliser nitrogen inputs. However, mixtures of grasses and white clover have frequently been associated with unstable and hence unreliable herbage

  15. [Spatiotemporal characteristics of MODIS NDVI in Hulunber Grassland].

    Science.gov (United States)

    Zhang, Hong-Bin; Yang, Gui-Xia; Wu, Wen-Bin; Li, Gang; Chen, Bao-Rui; Xin, Xiao-Ping

    2009-11-01

    Time-series MODIS NDVI datasets from 2000 to 2008 were used to study the spatial change trend, fluctuation degree, and occurrence time of the annual NDVImax of four typical grassland types, i.e., lowland meadow, temperate steppe, temperate meadow steppe, and upland meadow, in Hulunber Grassland. In 2000-2008, the vegetation in Hulunber Grassland presented an obvious deterioration trend. The mean annual NDVImax of the four grassland types had a great fluctuation, especially in temperate steppe where the maximum change in the mean value of annual NDVImax approximated to 50%. As for the area change of different grade grasslands, the areas with NDVImax between 0.4 and 1 accounted for about 91% of the total grassland area, which suggested the good vegetation coverage in the Grassland. However, though the areas with NDVImax values in (0.4, 0.8) showed an increasing trend, the areas with NDVImax values in (0.2, 0.4) and (0.8, 1) decreased greatly in the study period. Overall, the deteriorating grassland took up about 66.25% of the total area, and the restoring grassland took the rest. There was about 62.85% of the grassland whose NDVImax occurred between the 193rd day and the 225th day in each year, indicating that this period was the most important vegetation growth season in Hulunber Grassland.

  16. Contrasting microbial biogeographical patterns between anthropogenic subalpine grasslands and natural alpine grasslands.

    Science.gov (United States)

    Geremia, Roberto A; Pușcaș, Mihai; Zinger, Lucie; Bonneville, Jean-Marc; Choler, Philippe

    2016-02-01

    The effect of plant species composition on soil microbial communities was studied at the multiregional level. We compared the soil microbial communities of alpine natural grasslands dominated by Carex curvula and anthropogenic subalpine pastures dominated by Nardus stricta. We conducted paired sampling across the Carpathians and the Alps and used Illumina sequencing to reveal the molecular diversity of soil microbes. We found that bacterial and fungal communities exhibited contrasting regional distributions and that the distribution in each grassland is well discriminated. Beta diversity of microbial communities was much higher in C. curvula grasslands due to a marked regional effect. The composition of grassland-type core microbiomes suggest that C. curvula, and N. stricta to a lesser extent, tend to select a cohort of microbes related to antibiosis/exclusion, pathogenesis and endophytism. We discuss these findings in light of the postglacial history of the studied grasslands, the habitat connectivity and the disturbance regimes. Human-induced disturbance in the subalpine belt of European mountains has led to homogeneous soil microbial communities at large biogeographical scales. Our results confirm the overarching role of the dominant grassland plant species in the distribution of microbial communities and highlight the relevance of biogeographical history.

  17. EAARL Coastal Topography - Sandy Hook 2007

    Science.gov (United States)

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Stevens, Sara; Yates, Xan; Bonisteel, Jamie M.

    2008-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Northeast Coastal and Barrier Network, Kingston, RI; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of Gateway National Recreation Area's Sandy Hook Unit in New Jersey, acquired on May 16, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL) was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then

  18. Human activity accelerating the rapid desertification of the Mu Us Sandy Lands, North China

    Science.gov (United States)

    Miao, Yunfa; Jin, Heling; Cui, Jianxin

    2016-03-01

    Over the past several thousand years, arid and semiarid China has experienced a series of asynchronous desertification events in its semiarid sandy and desert regions, but the precise identification of the driving forces of such events has remained elusive. In this paper we identify two rapid desertification events (RDEs) at ~4.6 ± 0.2 ka BP and ~3.3 ± 0.2 ka BP from the JJ Profile, located in the eastern Mu Us Sandy Lands. These RDEs appear to have occurred immediately following periods marked by persistently frequent and intense fires. We argue that such fire patterns, directly linked to an uncontrolled human use of vegetation as fuel, played a key role in accelerating RDEs by ensuring that the land surface was degraded beyond the threshold required for rapid desertification. This would suggest that the future use of a massive and sustained ecological program of vegetation rehabilitation should reduce the risk of destructive fire.

  19. Changes in physical properties of sandy soil after long-term compost treatment

    Science.gov (United States)

    Aranyos, József Tibor; Tomócsik, Attila; Makádi, Marianna; Mészáros, József; Blaskó, Lajos

    2016-07-01

    Studying the long-term effect of composted sewage sludge application on chemical, physical and biological properties of soil, an experiment was established in 2003 at the Research Institute of Nyíregyháza in Hungary. The applied compost was prepared from sewage sludge (40%), straw (25%), bentonite (5%) and rhyolite (30%). The compost was ploughed into the 0-25 cm soil layer every 3rd year in the following amounts: 0, 9, 18 and 27 Mg ha-1 of dry matter. As expected, the compost application improved the structure of sandy soil, which is related with an increase in the organic matter content of soil. The infiltration into soil was improved significantly, reducing the water erosion under simulated high intensity rainfall. The soil compaction level was reduced in the first year after compost re-treatment. In accordance with the decrease in bulk density, the air permeability of soil increased tendentially. However, in the second year the positive effects of compost application were observed only in the plots treated with the highest compost dose because of quick degradation of the organic matter. According to the results, the sewage sludge compost seems to be an effective soil improving material for acidic sandy soils, but the beneficial effect of application lasts only for two years.

  20. Carbon sink activity of managed grasslands

    Science.gov (United States)

    Klumpp, Katja; Chabbi, Abad; Gastal, Francois; Senapati, Nimai; Charrier, Xavier; Darsonville, Olivier; Creme, Alexandra

    2017-04-01

    In agriculture, a large proportion of GHG emission saving potential may be achieved by means of soil C sequestration. Recent demonstrations of carbon sink activities however, often questioned the existence of C storing grasslands, as uncertainty surrounding estimates are often larger than the sink itself. Besides climate, key components of the carbon sink activity in grasslands are type and intensity of management practices. Here, we analysed long term data on C flux and soil organic carbon stocks for two long term (>13yrs) national observation sites in France (SOERE-ACBB). These sites comprise a number of grassland fields and managements options (i.e. permanent, sowing, grazing, mowing, and fertilization) offering an opportunity to study carbon offsets (i.e. compensation of CH4 and N2O emissions), climatic-management interactions and trade-offs concerning ecosystem services (e.g. production). Furthermore, for some grassland fields, the carbon sink activity was compared using two methods; repeated soil inventory and estimation of the ecosystem C budget by continuous measurement of CO2 exchange (i.e. eddy covariance) in combination with quantification of other C imports and exports, necessary to estimate net C storage. In general grasslands, were a potential sink of C (i.e. net ecosystem exchange, NEE), where grazed sites had lower NEE compared the cut site. However, when it comes to net C storage (NCS), mowing reduced markedly potential sink leading to very low NCS compared to grazed sites. Including non-CO2 fluxes (CH4 and N2O emission) in the budget, revealed that GHG emissions were offset by C sink activity.

  1. Did Hurricane Sandy influence the 2012 US presidential election?

    Science.gov (United States)

    Hart, Joshua

    2014-07-01

    Despite drawing on a common pool of data, observers of the 2012 presidential campaign came to different conclusions about whether, how, and to what extent "October surprise" Hurricane Sandy influenced the election. The present study used a mixed correlational and experimental design to assess the relation between, and effect of, the salience of Hurricane Sandy on attitudes and voting intentions regarding President Barack Obama and Mitt Romney in a large sample of voting-aged adults. Results suggest that immediately following positive news coverage of Obama's handling of the storm's aftermath, Sandy's salience positively influenced attitudes toward Obama, but that by election day, reminders of the hurricane became a drag instead of a boon for the President. In addition to theoretical implications, this study provides an example of how to combine methodological approaches to help answer questions about the impact of unpredictable, large-scale events as they unfold.

  2. Hurricane Sandy, Disaster Preparedness, and the Recovery Model.

    Science.gov (United States)

    Pizzi, Michael A

    2015-01-01

    Hurricane Sandy was the second largest and costliest hurricane in U.S. history to affect multiple states and communities. This article describes the lived experiences of 24 occupational therapy students who lived through Hurricane Sandy using the Recovery Model to frame the research. Occupational therapy student narratives were collected and analyzed using qualitative methods and framed by the Recovery Model. Directed content and thematic analysis was performed using the 10 components of the Recovery Model. The 10 components of the Recovery Model were experienced by or had an impact on the occupational therapy students as they coped and recovered in the aftermath of the natural disaster. This study provides insight into the lived experiences and recovery perspectives of occupational therapy students who experienced Hurricane Sandy. Further research is indicated in applying the Recovery Model to people who survive disasters. Copyright © 2015 by the American Occupational Therapy Association, Inc.

  3. Family Structures, Relationships, and Housing Recovery Decisions after Hurricane Sandy

    Directory of Open Access Journals (Sweden)

    Ali Nejat

    2016-04-01

    Full Text Available Understanding of the recovery phase of a disaster cycle is still in its infancy. Recent major disasters such as Hurricane Sandy have revealed the inability of existing policies and planning to promptly restore infrastructure, residential properties, and commercial activities in affected communities. In this setting, a thorough grasp of housing recovery decisions can lead to effective post-disaster planning by policyholders and public officials. The objective of this research is to integrate vignette and survey design to study how family bonds affected rebuilding/relocating decisions after Hurricane Sandy. Multinomial logistic regression was used to investigate respondents’ family structures before Sandy and explore whether their relationships with family members changed after Sandy. The study also explores the effect of the aforementioned relationship and its changes on households’ plans to either rebuild/repair their homes or relocate. These results were compared to another multinomial logistic regression which was applied to examine the impact of familial bonds on respondents’ suggestions to a vignette family concerning rebuilding and relocating after a hurricane similar to Sandy. Results indicate that respondents who lived with family members before Sandy were less likely to plan for relocating than those who lived alone. A more detailed examination shows that this effect was driven by those who improved their relationships with family members; those who did not improve their family relationships were not significantly different from those who lived alone, when it came to rebuilding/relocation planning. Those who improved their relationships with family members were also less likely to suggest that the vignette family relocate. This study supports the general hypothesis that family bonds reduce the desire to relocate, and provides empirical evidence that family mechanisms are important for the rebuilding/relocating decision

  4. Regime shift in sandy beach microbial communities following Deepwater Horizon oil spill remediation efforts.

    Directory of Open Access Journals (Sweden)

    Annette Summers Engel

    Full Text Available Sandy beaches support a wide variety of underappreciated biodiversity that is critical to coastal ecosystems. Prior to the 2010 Deepwater Horizon oil spill, the diversity and function of supratidal beach sediment microbial communities along Gulf of Mexico coastlines were not well understood. As such, it was unclear if microbial community compositional changes would occur following exposure to beached oil, if indigenous communities could biodegrade oil, or how cleanup efforts, such as sand washing and sediment redistribution, would impact microbial ecosystem resiliency. Transects perpendicular to the shoreline were sampled from public beaches on Grand Isle, Louisiana, and Dauphin Island, Alabama, over one year. Prior to oil coming onshore, elevated levels of bacteria associated with fecal contamination were detected (e.g., Enterobacteriales and Campylobacterales. Over time, significant shifts within major phyla were identified (e.g., Proteobacteria, Firmicutes, Actinobacteria and fecal indicator groups were replaced by taxa affiliated with open-ocean and marine systems (e.g., Oceanospirillales, Rhodospirillales, and Rhodobacterales. These new bacterial groups included putative hydrocarbon degraders, similar to those identified near the oil plume offshore. Shifts in the microbial community composition strongly correlated to more poorly sorted sediment and grain size distributional changes. Natural oceanographic processes could not account for the disrupted sediment, especially from the backshore well above the maximum high-tide levels recorded at these sites. Sand washing and tilling occurred on both open beaches from August through at least December 2010, which were mechanisms that could replace fecal indicator groups with open-ocean groups. Consequently, remediation efforts meant to return beaches to pre-spill compositions caused a regime shift that may have added potential ecosystem function, like hydrocarbon degradation, to the sediment

  5. Regime shift in sandy beach microbial communities following Deepwater Horizon oil spill remediation efforts.

    Science.gov (United States)

    Engel, Annette Summers; Gupta, Axita A

    2014-01-01

    Sandy beaches support a wide variety of underappreciated biodiversity that is critical to coastal ecosystems. Prior to the 2010 Deepwater Horizon oil spill, the diversity and function of supratidal beach sediment microbial communities along Gulf of Mexico coastlines were not well understood. As such, it was unclear if microbial community compositional changes would occur following exposure to beached oil, if indigenous communities could biodegrade oil, or how cleanup efforts, such as sand washing and sediment redistribution, would impact microbial ecosystem resiliency. Transects perpendicular to the shoreline were sampled from public beaches on Grand Isle, Louisiana, and Dauphin Island, Alabama, over one year. Prior to oil coming onshore, elevated levels of bacteria associated with fecal contamination were detected (e.g., Enterobacteriales and Campylobacterales). Over time, significant shifts within major phyla were identified (e.g., Proteobacteria, Firmicutes, Actinobacteria) and fecal indicator groups were replaced by taxa affiliated with open-ocean and marine systems (e.g., Oceanospirillales, Rhodospirillales, and Rhodobacterales). These new bacterial groups included putative hydrocarbon degraders, similar to those identified near the oil plume offshore. Shifts in the microbial community composition strongly correlated to more poorly sorted sediment and grain size distributional changes. Natural oceanographic processes could not account for the disrupted sediment, especially from the backshore well above the maximum high-tide levels recorded at these sites. Sand washing and tilling occurred on both open beaches from August through at least December 2010, which were mechanisms that could replace fecal indicator groups with open-ocean groups. Consequently, remediation efforts meant to return beaches to pre-spill compositions caused a regime shift that may have added potential ecosystem function, like hydrocarbon degradation, to the sediment. Future research will

  6. 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).

  7. Coastal Topography--Northeast Atlantic Coast, Post-Hurricane Sandy, 2012

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Derived products of a portion of the New York, Delaware, Maryland, Virginia, and North Carolina coastlines, post-Hurricane Sandy (Sandy was an October 2012...

  8. Coastal Topography--Northeast Atlantic Coast, Post-Hurricane Sandy, 2012: Lidar-extracted dune features

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Dune crest and toe positions along a portion of the New York, Delaware, Maryland, Virginia, and North Carolina coastlines, post-Hurricane Sandy (Sandy was an October...

  9. Coastal Topography--Northeast Atlantic Coast, Post-Hurricane Sandy, 2012

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Derived products of a portion of the New York, Delaware, Maryland, Virginia, and North Carolina coastlines, post-Hurricane Sandy (Sandy was an October 2012 hurricane...

  10. 2012 U.S. Geological Survey Topographic Lidar: Northeast Atlantic Coast Post-Hurricane Sandy

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Binary point-cloud data were produced for a portion of the New York, Delaware, Maryland, Virginia, and North Carolina coastlines, post-Hurricane Sandy (Sandy was an...

  11. Coastal Topography--Northeast Atlantic Coast, Post-Hurricane Sandy, 2012: Digital elevation model (DEM)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A DEM was produced for a portion of the New York, Delaware, Maryland, Virginia, and North Carolina coastlines, post-Hurricane Sandy (Sandy was an October 2012...

  12. 2012 U.S. Geological Survey Topographic Lidar: Northeast Atlantic Coast Post-Hurricane Sandy

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Binary point-cloud data were produced for a portion of the New York, Delaware, Maryland, Virginia, and North Carolina coastlines, post-Hurricane Sandy (Sandy was an...

  13. STATUS, CAUSES AND COMBATING SUGGESTIONS OF SANDY DESERTIFICATION IN QINGHAI-TIBET PLATEAU

    Institute of Scientific and Technical Information of China (English)

    LIU Yi-hua; DONG Guang-rong; LI Sen; DONG Yu-xiang

    2005-01-01

    The Qinghai-Tibet Plateau is one of the major sandy desertification regions of China. Based on the recent investigation on sandy desertification, this paper analyses the status such as the type, area, distribution and damage of sandy land desertification in the plateau. Through the analysis on the factors affecting sandy desertification in the region's natural and socio-economic systems as well as the processes and their interrelations, it can be concluded that sandy desertification in the Qinghai-Tibet Plateau resulted from the combined actions of normal natural sand drift processes, natural sandy desertification processes caused by climatic changes and man-made sandy desertification caused by improper human activities. In addition, it also predicts the possible developmental trend including the increase in desertification area and the enhancement in desertification developmental degree with the exacerbation of the complex processes, and finally puts forward some strategic suggestions to combat sandy desertification in the coming years.

  14. Controlled release fertilizer increased phytoremediation of petroleum-contaminated sandy soil.

    Science.gov (United States)

    Cartmill, Andrew D; Cartmill, Donita L; Alarcón, Alejandro

    2014-01-01

    A greenhouse experiment was conducted to determine the effect of the application of controlled release fertilizer [(CRF) 0, 4,6, or 8 kg m(-3)] on Lolium multiflorum Lam. survival and potential biodegradation of petroleum hydrocarbons (0, 3000, 6000, or 15000 mg kg(-1)) in sandy soil. Plant adaptation, growth, photosynthesis, total chlorophyll, and proline content as well as rhizosphere microbial population (culturable heterotrophic fungal and bacterial populations) and total petroleum hydrocarbon (TPH)-degradation were determined. Petroleum induced-toxicity resulted in reduced plant growth, photosynthesis, and nutrient status. Plant adaptation, growth, photosynthesis, and chlorophyll content were enhanced by the application of CRF in contaminated soil. Proline content showed limited use as a physiological indicator of petroleum induced-stress in plants. Bacterial and filamentous fungi populations were stimulated by the petroleum concentrations. Bacterial populations were stimulated by CRF application. At low petroleum contamination, CRF did not enhance TPH-degradation. However, petroleum degradation in the rhizosphere was enhanced by the application of medium rates of CRF, especially when plants were exposed to intermediate and high petroleum contamination. Application of CRF allowed plants to overcome the growth impairment induced by the presence of petroleum hydrocarbons in soils.

  15. Non-native plants and soil microbes: potential contributors to the consistent reduction in soil aggregate stability caused by the disturbance of North American grasslands.

    Science.gov (United States)

    Duchicela, Jessica; Vogelsang, Keith M; Schultz, Peggy A; Kaonongbua, Wittaya; Middleton, Elizabeth L; Bever, James D

    2012-10-01

    • Soil aggregate stability is an important ecosystem property that is altered by anthropogenic disturbance. Yet, the generalization of these alterations and the identification of the main contributors are limited by the absence of cross-site comparisons and the application of inconsistent methodologies across regions. • We assessed aggregate stability in paired remnant and post-disturbance grasslands across California, shortgrass and tallgrass prairies, and in manipulative experiments of plant composition and soil microbial inoculation. • Grasslands recovering from anthropogenic disturbance consistently had lower aggregate stability than remnants. Across all grasslands, non-native plant diversity was significantly associated with reduced soil aggregate stability. A negative effect of non-native plants on aggregate stability was also observed in a mesocosm experiment comparing native and non-native plants from California grasslands. Moreover, an inoculation study demonstrated that the degradation of the microbial community also contributes to the decline in soil aggregate stability in disturbed grasslands. • Anthropogenic disturbance consistently reduced water-stable aggregates. The stability of aggregates was reduced by non-native plants and the degradation of the native soil microbial community. This latter effect might contribute to the sustained decline in aggregate stability following anthropogenic disturbance. Further exploration is advocated to understand the generality of these potential mechanisms.

  16. Effects of soil amendment on soil characteristics and maize yield in Horqin Sandy Land

    Science.gov (United States)

    Zhou, L.; Liu, J. H.; Zhao, B. P.; Xue, A.; Hao, G. C.

    2016-08-01

    A 4-year experiment was conducted to investigate the inter-annual effects of sandy soil amendment on maize yield, soil water storage and soil enzymatic activities in sandy soil in Northeast China in 2010 to 2014. We applied the sandy soil amendment in different year, and investigated the different effects of sandy soil amendment in 2014. There were six treatments including: (1) no sandy soil amendment application (CK); (2) one year after applying sandy soil amendment (T1); (3) two years after applying sandy soil amendment(T2); (4) three years after applying sandy soil amendment(T3); (5)four years after applying sandy soil amendment(T4); (6) five years after applying sandy soil amendment (T5). T refers to treatment, and the number refers to the year after application of the sandy soil amendment. Comparing with CK, sandy soil amendments improved the soil water storage, soil urease, invertase, and catalase activity in different growth stages and soil layers, the order of soil water storage in all treatments roughly performed: T3 > T5 > T4 > T2 > T1 > CK. the order of soil urease, invertase, and catalase activity in all treatments roughly performed: T5 > T3 > T4 > T2 > T1 > CK. Soil application of sandy soil amendment significantly (p≤⃒0.05) increased the grain yield and biomass yield by 22.75%-41.42% and 29.92%-45.45% respectively, and maize yield gradually increased with the years go by in the following five years. Sandy soil amendment used in poor sandy soil had a positive effect on soil water storage, soil enzymatic activities and maize yield, after five years applied sandy soil amendment (T5) showed the best effects among all the treatments, and deserves further research.

  17. Structure and Processes in Temperate Grassland Vegetation

    DEFF Research Database (Denmark)

    Ejrnæs, R.

    these lies the question of the origin of species. [This English text (Warming 1909) is a word for word translation of the original Danish text] The present thesis is the outcome of a three year PhD-study intended to cast light on the occurrence, nature and management of seminatural grasslands on well......-drained soils in Denmark. Rules-of-thumb are merely very simple models, and this study may thus be seen as an attempt to validate, correct or even invent new simple models of relevance for Danish grassland vegetation - and, to give these models an appropriate biological interpretation. The thesis could not have...... Moora. Not least, I acknowledge the coherent and inspiring studies and writing of scientists, that masters the admirable project of creating and pursuing original ideas incorporating research results from within many scientific disciplines. They make it worth carrying on doing research, and for this, I...

  18. Deaths associated with Hurricane Sandy - October-November 2012.

    Science.gov (United States)

    2013-05-24

    On October 29, 2012, Hurricane Sandy hit the northeastern U.S. coastline. Sandy's tropical storm winds stretched over 900 miles (1,440 km), causing storm surges and destruction over a larger area than that affected by hurricanes with more intensity but narrower paths. Based on storm surge predictions, mandatory evacuations were ordered on October 28, including for New York City's Evacuation Zone A, the coastal zone at risk for flooding from any hurricane. By October 31, the region had 6-12 inches (15-30 cm) of precipitation, 7-8 million customers without power, approximately 20,000 persons in shelters, and news reports of numerous fatalities (Robert Neurath, CDC, personal communication, 2013). To characterize deaths related to Sandy, CDC analyzed data on 117 hurricane-related deaths captured by American Red Cross (Red Cross) mortality tracking during October 28-November 30, 2012. This report describes the results of that analysis, which found drowning was the most common cause of death related to Sandy, and 45% of drowning deaths occurred in flooded homes in Evacuation Zone A. Drowning is a leading cause of hurricane death but is preventable with advance warning systems and evacuation plans. Emergency plans should ensure that persons receive and comprehend evacuation messages and have the necessary resources to comply with them.

  19. Hurricane Sandy: An Educational Bibliography of Key Research Studies

    Science.gov (United States)

    Piotrowski, Chris

    2013-01-01

    There, undoubtedly, will be a flurry of research activity in the "Superstorm" Sandy impact area on a myriad of disaster-related topics, across academic disciplines. The purpose of this study was to review the disaster research related specifically to hurricanes in the educational and social sciences that would best serve as a compendium…

  20. Patterns of species richness in sandy beaches of South America

    African Journals Online (AJOL)

    Species richness of the intertidal macroinfauna of exposed sandy beaches around South America is reviewed in relation ... The middle shore is prim

  1. Microfungi diversity isolation from sandy soil of Acapulco touristic beaches

    Science.gov (United States)

    Microscopic fungi diversity in marine sandy soil habitats is associated with key functions of beach ecosystems. There are few reports on their presence in Mexican beaches. Although standard methods to obtain the fungi from soil samples are established, the aim of this pilot study was to test the pla...

  2. 中国草原利用、保护与建设评析及政策建议%Policy Recommendations and Assessment of Grasslands Utilization ,Protection and Construction in China

    Institute of Scientific and Technical Information of China (English)

    张立中

    2012-01-01

    我国草原面积广袤,生态功能和服务功能突出,草原区地处祖国边疆,也是少数民族聚居区,探讨草原的持续利用意义重大.退牧还草等草原生态保护建设工程的实施,草原退化势头得到遏制,但受超载过牧、自由放牧、草原建设投入不足及气候暖干化等因素影响,草原退化局面仍未得到根本扭转.为此,应在完善草原承包制基础上,建立健全草原生态补偿机制,构筑社会保障体系和草原生态保护政策支持体系,强化草原监理,并加大草产业研发投入和科技成果转化力度,实现草原可持续利用.%In China, for there are vast grasslands area, the ecological performance and service performance is outstanding, while the grasslands is located in the border area of motherland, where minority are resident, so it is significant to research the sustainable utilization of grasslands. Although the implementation of grasslands Conservatory Ecology project, such as returning grazing land to grasslands, has restrained the grasslands degradation trend. But by overgrazing, freely grazing, grasslands construction input shortage and climate warming and drying, and other factors, the grasslands degradation situation has not yet been fundamentally reversed. Therefore, on the basis of improving the grasslands contracting system, establish and improve the grasslands ecological compensation mechanism to build a social security system and grasslands ecological protection policy support system, strengthen the grasslands supervision and increase grass industry research and development investment and science and technology production conversion efforts to achieve sustainable utilization of grasslands.

  3. Structure and Processes in Temperate Grassland Vegetation

    DEFF Research Database (Denmark)

    Ejrnæs, R.

    In Denmark, the grass greens in late March. Perhaps that is the reason why early spring is so well suited to classify grasslands according to conservation value by their colour. When there is no interference by summer drought and autumn litter, a marked difference can be observed between the unif...... would like to honour John Philip Grime, Stephen Jay Gould, R.H. Whittaker and Eugen Warming....

  4. 78 FR 46999 - Additional Waivers and Alternative Requirements for Hurricane Sandy Grantees in Receipt of...

    Science.gov (United States)

    2013-08-02

    ... URBAN DEVELOPMENT Additional Waivers and Alternative Requirements for Hurricane Sandy Grantees in... impacted and distressed areas declared a major disaster due to Hurricane Sandy (see 78 FR 14329, published....) (Stafford Act), due to Hurricane Sandy and other eligible events in calendar years 2011, 2012, and 2013....

  5. 77 FR 74891 - Order Granting Exemptions From Certain Rules of Regulation SHO Related to Hurricane Sandy

    Science.gov (United States)

    2012-12-18

    ... COMMISSION Order Granting Exemptions From Certain Rules of Regulation SHO Related to Hurricane Sandy December 12, 2012. I. Introduction Hurricane Sandy made landfall along the mid-Atlantic Coast on October 29... in the Vault at the time Hurricane Sandy made landfall, facilitating DTCC's ability to...

  6. 78 FR 33467 - Second Allocation of Public Transportation Emergency Relief Funds in Response to Hurricane Sandy...

    Science.gov (United States)

    2013-06-04

    ... Response to Hurricane Sandy: Response, Recovery & Resiliency; Correction AGENCY: Federal Transit... by Hurricane Sandy. This amount was in addition to the initial $2 billion allocation announced in the... allocation restoration FTA Section 5324 Emergency Relief Program Allocations for Hurricane Sandy, by...

  7. 33 CFR 165.507 - Security Zone; Chesapeake Bay, between Sandy Point and Kent Island, MD.

    Science.gov (United States)

    2010-07-01

    ... south (eastbound) span of the William P. Lane Jr. Memorial Bridge, from the western shore at Sandy Point..., between Sandy Point and Kent Island, MD. 165.507 Section 165.507 Navigation and Navigable Waters COAST... Guard District § 165.507 Security Zone; Chesapeake Bay, between Sandy Point and Kent Island, MD. (a...

  8. Potential Effects of the Loss of Native Grasses on Grassland Invertebrate Diversity in Southeastern Australia

    Directory of Open Access Journals (Sweden)

    Roger Edgcumbe Clay

    2014-01-01

    Full Text Available Reduction in area of the southeastern temperate grasslands of Australia since European settlement has been accompanied by degradation of remaining remnants by various factors, including the replacement of native plant species by introduced ones. There are suggestions that these replacements have had deleterious effects on the invertebrate grassland community, but there is little evidence to support these suggestions. In the eastern Adelaide Hills of South Australia, four grassland invertebrate sampling areas, in close proximity, were chosen to be as similar as possible except for the visible amount of native grass they contained. Sample areas were surveyed in four periods (summer, winter, spring, and a repeat summer using pitfall traps and sweep-netting. A vegetation cover survey was conducted in spring. Morphospecies richness and Fisher’s alpha were compared and showed significant differences between sample areas, mainly in the summer periods. Regression analyses between morphospecies richness and various features of the groundcover/surface showed a strong positive and logical association between native grass cover and morphospecies richness. Two other associations with richness were less strong and lacked a logical explanation. If the suggested direct effect of native grass cover on invertebrate diversity is true, it has serious implications for the conservation of invertebrate biodiversity.

  9. PHYTOSOCIOLOGICAL DATABASE OF SLOVAK GRASSLAND VEGETATION

    Directory of Open Access Journals (Sweden)

    M. JANISOVA

    2007-04-01

    Full Text Available In Slovakia, the Central Phytosociological Database has been built since 1996 and it is located in the Institute of Botany, Slovak Academy of Sciences, Bratislava. Since 2005, we focused on the collection of phytosociological relevés from semi-natural grassland communities belonging to phytosociological classes Molinio-Arrhenatheretea, Festuco-Brometea and Nardetea strictae. All accessible published relevés were compiled and stored in the Turboveg program. Since 1990 an extensive field survey was caried out with the aim to record the actual stage of semi-natural grasslands in Slovakia after the period of profound land-use changes (collectivisation, abandonment, succession. As a result of this survey, 4988 of recent unpublished relevés were stored in our database. Alltogether, the database of grassland vegetation contains 11 121 relevés, collected by 143 authors between 1924 and 2006. These relevés include 387 765 vascular plants individual records nad 6 439 records of bryophyte and lichen species. The basic statistical information on this database is presented in the paper and the quality of the data is discussed. The possible application of such phytosociological dataset is outlined.

  10. PHYTOSOCIOLOGICAL DATABASE OF SLOVAK GRASSLAND VEGETATION

    Directory of Open Access Journals (Sweden)

    I SKODOVA

    2007-01-01

    Full Text Available In Slovakia, the Central Phytosociological Database has been built since 1996 and it is located in the Institute of Botany, Slovak Academy of Sciences, Bratislava. Since 2005, we focused on the collection of phytosociological relevés from semi-natural grassland communities belonging to phytosociological classes Molinio-Arrhenatheretea, Festuco-Brometea and Nardetea strictae. All accessible published relevés were compiled and stored in the Turboveg program. Since 1990 an extensive field survey was caried out with the aim to record the actual stage of semi-natural grasslands in Slovakia after the period of profound land-use changes (collectivisation, abandonment, succession. As a result of this survey, 4988 of recent unpublished relevés were stored in our database. Alltogether, the database of grassland vegetation contains 11 121 relevés, collected by 143 authors between 1924 and 2006. These relevés include 387 765 vascular plants individual records nad 6 439 records of bryophyte and lichen species. The basic statistical information on this database is presented in the paper and the quality of the data is discussed. The possible application of such phytosociological dataset is outlined.

  11. Deposition fluxes of terpenes over grassland

    Science.gov (United States)

    Bamberger, I.; HöRtnagl, L.; Ruuskanen, T. M.; Schnitzhofer, R.; Müller, M.; Graus, M.; Karl, T.; Wohlfahrt, G.; Hansel, A.

    2011-07-01

    Eddy covariance flux measurements were carried out for two subsequent vegetation periods above a temperate mountain grassland in an alpine valley using a proton-transfer-reaction-mass spectrometer (PTR-MS) and a PTR time-of-flight-mass spectrometer (PTR-TOF). In 2008 and during the first half of the vegetation period 2009 the volume mixing ratios (VMRs) for the sum of monoterpenes (MTs) were typically well below 1 ppbv and neither MT emission nor deposition was observed. After a hailstorm in July 2009 an order of magnitude higher amount of terpenes was transported to the site from nearby coniferous forests causing elevated VMRs. As a consequence, deposition fluxes of terpenes to the grassland, which continued over a time period of several weeks without significant reemission, were observed. For days without precipitation the deposition occurred at velocities close to the aerodynamic limit. In addition to monoterpene uptake, deposition fluxes of the sum of sesquiterpenes (SQTs) and the sum of oxygenated terpenes (OTs) were detected. Considering an entire growing season for the grassland (i.e., 1 April to 1 November 2009), the cumulative carbon deposition of monoterpenes reached 276 mg C m-2. This is comparable to the net carbon emission of methanol (329 mg C m-2), which is the dominant nonmethane volatile organic compound (VOC) emitted from this site, during the same time period. It is suggested that deposition of monoterpenes to terrestrial ecosystems could play a more significant role in the reactive carbon budget than previously assumed.

  12. Effects of leafy spurge infestation on grassland birds

    Science.gov (United States)

    Scheiman, D.M.; Bollinger, E.K.; Johnson, D.H.

    2003-01-01

    Grassland bird populations are declining. Invasive plant species may be contributing to these declines by altering habitat quality. However, the effects of invasive plants on grassland birds are largely unknown. Leafy spurge (Euphorbia esula) is an exotic, invasive weed in the northern Great Plains. We examined the effects of leafy spurge infestation on densities of breeding birds, nest-site selection, and nest success in grasslands on the Sheyenne National Grassland (SNG), North Dakota, USA, 1999-2000. We categorized spurge-infested grasslands into 3 groups (low, medium, high), based on the area covered by spurge patches. We surveyed 75 100-m-radius circular points (25 in each group), and searched for nests in 6 16-ha plots (2 in each group). Grasshopper sparrow (Ammodramus savannarum) and savannah sparrow (Passerculus sandwichensis) densities were lower on high-spurge points than on low- and medium-spurge points. Bobolink (Dolichonyx oryzivorus) and western meadowlark (Sturnella neglecta) densities were not significantly different among spurge cover groups. Spurge cover did not appear to be an important factor in nest-site selection. However, western meadowlark nest success was positively associated with spurge cover. Vegetation structure is an important indicator of habitat quality and resource availability for grassland birds. Changes in vegetation structure caused by introduced plant species, such as spurge, can alter resource availability and hence affect bird community composition. Managers of spurge-infested grasslands should continue current spurge control measures to help prevent further declines in grassland habitat quality and grassland bird populations.

  13. Can species-specific differences in foliar chemistry influence leaf litter decomposition in grassland species?

    Science.gov (United States)

    Sanaullah, M.; Chabbi, A.; Rumpel, C.

    2009-04-01

    The influence of litter quality on its rate of decomposition is a crucial aspect of C cycle. In this study we concentrated on grassland ecosystems where leaf litter is one of the major sources of C input. To quantify the contribution of initial leaf chemistry within different plant species, the decomposition of chemically different leaf litter of three grassland species (Lolium perenne, Festuca arundinacea and Dactylis glomerata) was monitored, using the litter bag technique. Litter of different maturity stages i.e. green (fresh leaves) and brown litter (brown leaves were still attached to the plant), were incubated on bare soil surface. Samples were taken at different time intervals (0, 2, 4, 8, 20 and 44 weeks) and were analyzed for mass loss, organic C and N contents and stable isotopic signatures (C and N). Changes in litter chemistry were addressed by determining lignin-derived phenols after CuO oxidation and non-cellulosic polysaccharides after acid hydrolysis followed by gas chromatography. Green litter was chemically different from brown litter due to higher initial N and lower lignin contents. While in grassland species, both L. perenne and D. glomerata were similar in their initial chemical composition compared with F. arundinacea. Green litter showed higher rate of degradation. In green litter, Percent lignin remaining of initial (% OI) followed the similar decomposition pattern as of C remaining indicating lignin as controlling factor in decomposition. Constant Acid-to-Aldehyde ratios of lignin-derived phenols (vanillyl and syringyl) did not suggest any transformation in lignin structures. In green litter, increase in non-cellulosic polysaccharides ratios (C6/C5 and deoxy/C5) proposed microbial-derived sugars, while there was no significant increase in these ratios in brown litter. In conclusion, due to the differences in initial chemical composition (initial N and lignin contents), green litter decomposition was higher than brown litter in all

  14. [Ecological distribution of arbuscular mycorrhizal fungi in alpine grasslands of Tibet Plateau].

    Science.gov (United States)

    Cai, Xiao-bu; Peng, Yue-lin; Gai, Jing-ping

    2010-10-01

    Seventy soil samples with the roots of 37 dominant or common plant species on the grasslands in south and north Tibet Plateau were collected to study the ecological distribution of arbuscular mycorrhizal (AM) fungi in the investigation area. A total of 35 AM fungi species belonging to 5 genera were isolated, among which, 18 species belonged to Glomus, 9 species belonged to Acaulospora, 6 species belonged to Scutellospora, 1 species belonged to Entrophospora, and 1 species belonged to Paraglomus. There were 23 AM fungi species belonging to 4 genera isolated from south Tibet, and 22 species belonging to 4 genera from north Tibet. The Shannon diversity index of AM fungi in south and north Tibet Plateau was 2.31 and 2.75, respectively, and the spore density and species richness were significantly higher in north Tibet than in south Tibet. In different ecological zones, lesser AM fungi common species were found, species distribution was more site-specific, and different dominant species were observed. In alpine grassland, mountain meadow, and alpine meadow, the Shannon index of AM fungi was 1.91, 1.83, and 1.80, respectively; while in severely degraded temperate grassland, this index was only 1.64. The highest species richness of AM fungi occurred at the altitude of 4000-4600 m, but the highest Shannon index and species evenness occurred at the altitude of 4600-5220 m, with the values being 2.42 and 0.79, respectively. At all altitudes, Glomus was the dominant genus, and its relative abundance was higher when the altitude was below 4000 m. Acaulospora was mainly observed at the altitudes higher than 4000 m, Scutellospora was mainly distributed at the altitude 3500-5220 m, Paraglomus mainly occurred in the north alpine meadow with an altitude of 4000-5220 m and occasionally in the alpine steppe, whereas Entrophospora was only found in the south temperate grassland with an altitude of 3500-3700 m.

  15. Long-term grassland management effects on soil Phosphorus status on rewetted Histosols

    Science.gov (United States)

    Heller, Sebastian; Müller, Jürgen; Kayser, Manfred

    2017-04-01

    Since the Neolithic Period, the cultivation of wetlands has played a significant role for the settlement of Humans northwest Germany. A continuing drainage of the wetlands over the centuries and an intensified soil cultivation during the last decades has caused irreversible peat degradation and led to fundamental changes in the landscape. Nowadays, almost 70 % of the 4345 km2 peatland of Lower Saxony is altered by agriculture. For the revitalization of wetland ecosystems, permanent rewetting is an integral component to preserve the functions of organic soils and achieve resilient, speciesrich wetlands. However, permanent rewetting measures are not always feasible. In our study area at the Osterfeiner Moor, a fen located in the Dümmer lowlands near Osnabrück, intensive forage cropping areas were converted into extensive permanent grasslands accompanied by temporary rewetting during winter. This management practice combined with zero fertilization and a low mowing and grazing intensity aims at mitigating mineralisation of peat layers and creating a habitat for endangered meadow bird species. In this semi-natural ecosystem soil phosphorus (P) dynamics play a crucial role. However, longterm research results on P availability of degraded and rewetted fens are still lacking. Thus, we investigated the interaction of different grassland uses and P dynamics in the soil. We described P depletion of the topsoil over a time scale of 17 years after the implementation of restoration measures. Our study site comprises of 180 ha protected grassland divided into 52 management plots. According to the management system, we divided the plots into meadows, pastures and combinations of cutting and grazing. The soils in our study area can be characterised as drained organic soils, WRB: Rheic Sapric Histosols (Drainic), with drastic degradation properties through moorsh forming processes. Plant-available P (double lactate extraction method: PDL) was analysed from representative topsoil

  16. Responses of plant diversity and primary productivity to nutrient addition in aStipa baicalensis grassland, China

    Institute of Scientific and Technical Information of China (English)

    YU Li; SONG Xiao-long; ZHAO Jian-ning; WANG Hui; BAI Long; YANG Dian-lin

    2015-01-01

    Nutrient addition can affect the structure and diversity of grassland plant communities, thus alter the grassland productivity. Studies on grassland plant community composition, structure and diversity in response to nutrient addition have an import-ant theoretical and practical signiifcance for the scientiifc management of grassland, protection of plant diversity and the recovery of degraded grassland. A randomized block design experiment was conducted with six blocks of eight treatments each: control (no nutrient addition) and K, P, N, PK, NK, NP, and NPK addition. We evaluated plant composition, height, coverage, density, and aboveground biomass to estimate primary productivity and plant diversity. Results showed that al treatments increased primary productivity signiifcantly (P<0.05) with the exception of the K and the NPK treatments had the greatest effect, increasing aboveground biomass 2.46 times compared with the control (P<0.05). One-way ANOVA and factorial analysis were used for the species richness, Shannon-Wiener index, Pielou index and aboveground biomass, and the relationships between the diversity indices and aboveground biomass were determined through linear regression. We found that fertilization altered the community structure; N (but not P or K) addition increased the proportion of perennial rhizome grasses and signiifcantly reduced that of perennial forbs (P<0.05), thus it presented a trend of decrease in species richness, Shannon-Wiener and Pielou indexex, respectively. Only the main effects of N had signiifcant impacts on both the diversity indices and the aboveground biomass (P<0.05), and the interactions between N-P, N-K, P-K and N-P-K could be neglected. With fertilization, plant diversity (correlation coefifcient, –0.61), species richness (–0.49), and species even-ness (–0.51) were al negatively linearly correlated with primary productivity. The correlations were al signiifcant (P<0.01). Scientiifc nutrient management is an effective

  17. Pasture management controls soil organic matter stocks, properties, and biochemical functioning in Tibetan grasslands

    Science.gov (United States)

    Spielvogel, Sandra; Breidenbach, Andreas; de la Haye, Tilman; Schleuß, Per; Kuzyakov, Yakov; Guggenberger, Georg

    2016-04-01

    The Tibetan Plateau hosts the highest and largest pasture ecosystem worldwide, and provides tremendous sinks for carbon. Due to the sheer size of the of the Tibetan Plateau, feedback effects of soil organic carbon (OC) losses from inadequate grassland management are of undisputed relevance for ecosystem stability and future global change scenarios. Given the vital importance of the Tibetan steppes as global OC sinks, we combined data on OC stocks from own studies with an extensive literature review on soils developed under montane and alpine Kobresia pygmaea and Stipa grandis pastures. We calculated soil OC stocks at the Tibetan Plateau within the first 30 cm of the soil profile depending on pasture management and climate. Vertical gradients of δ13C values, neutral sugar, cutin and suberin contents, lignin phenol contents as well as microbial community composition (t-RFLP analysis, 16S rDNA und IST sequencing) and activities of six extracellular enzymes involved in the C, N, and P cycle were assessed. The depth gradients of these parameters reflected degradation processes from intact Kobresia pastures (stage 0) to pronounced degradation (bare soil; stage 5). Moderate husbandry is beneficial for the storage of OC, nitrogen (N) and other nutrients (e.g. phosphorus) for the majority of the montane grasslands of the Tibetan Plateau (i.e., Kobresia pygmaea pastures). However, Kobresia root mats originated from grazing are affected by desiccations and frost, which cause polygonal cracking and initiates soil erosion. This process is accelerated under high grazing pressure (overgrazing) that enhances root mat degradation. Increasing degradation caused by large herbivore densities resulted in an increased OC decomposition demonstrated by decreasing δ13C values. The δ13C shift towards more negative values reflects the relative enrichment of 13C depleted lignin components during OC decomposition in the strongly disturbed soil. Translocation of topsoil material into the

  18. Floristic diversity and effect of anthropogenic activities on human-dominated grasslands in subtropical regions of Peninsular India

    Directory of Open Access Journals (Sweden)

    Mandar N. Datar

    2016-01-01

    Full Text Available Indian subtropical grasslands are secondary habitats formed due to anthropogenic activities resulting in degradation of deciduous forests. Spread throughout Peninsular and Central India, they are important from economic and ecological points of view and are the prime source of fodder for the large population of livestock in this region. Pastures are either exposed to open grazing or protected and harvested periodically for fodder. In the present investigation floristic diversity of 21 sites from Western Ghats and Central India was studied, along with the effects of anthropogenic activities like burning and grazing on floristic composition in general and palatable species in particular. Over-grazing and burning were found to result in dominance of unpalatable species, making the grasslands less useful for livestock production. High rainfall and protection by local communities seem to play important roles in the dominance of palatable species in grasslands. Our results suggest that periodic harvesting and protection from burning and over-grazing should be encouraged and implemented in order to increase the potential of these grasslands for livestock production. Detailed studies are warranted to confirm these findings.Keywords: Burning, community protection, grazing, palatable species, pastures.DOI: 10.17138/TGFT(48-18

  19. Satellite Observed Widespread Decline in Mongolian Grasslands Largely Due to Overgrazing

    Science.gov (United States)

    Hilker, Thomas; Natsagdorj, Enkhjargal; Waring, Richard H.; Lyapustin, Alexei; Wang, Yujie

    2014-01-01

    The Mongolian Steppe is one of the largest remaining grassland ecosystems. Recent studies have reported widespread decline of vegetation across the steppe and about 70 percent of this ecosystem is now considered degraded. Among the scientific community there has been an active debate about whether the observed degradation is related to climate, or overgrazing, or both. Here, we employ a new atmospheric correction and cloud screening algorithm (MAIAC) to investigate trends in satellite observed vegetation phenology. We relate these trends to changes in climate and domestic animal populations. A series of harmonic functions is fitted to MODIS observed phenological curves to quantify seasonal and inter-annual changes in vegetation. Our results show a widespread decline (of about 12 percent on average) in MODIS observed NDVI across the country but particularly in the transition zone between grassland and the Gobi desert, where recent decline was as much as 40 percent below the 2002 mean NDVI. While we found considerable regional differences in the causes of landscape degradation, about 80 percent of the decline in NDVI could be attributed to increase in livestock. Changes in precipitation were able to explain about 30 percent of degradation across the country as a whole but up to 50 percent in areas with denser vegetation cover (p0.05). Temperature changes, while significant, played only a minor role (r20.10, p0.05). Our results suggest that the cumulative effect of overgrazing is a primary contributor to the degradation of the Mongolian steppe and is at least partially responsible for desertification reported in previous studies.

  20. The biogenic emission potential of nitric oxide from sandy soils

    Science.gov (United States)

    Yu, J. B.; Meixner, F. X.; Sun, Z. G.; Chen, X. B.; Mamtimin, B.

    2009-04-01

    There are about 160.9 Mha of sandy land in China, about 17.6% of total Chinese area, which mainly distributed in 35°-50° N. The western Songnen Plain, which located in the semi-arid region of Northeastern China, is one of the main sandy soil distribution regions. The changes of land use in sandy soil are accompanied by changes in biogeochemical cycles of nutrients, particularly of the air-surface exchange of trace gases like nitric oxide. Our study, based on results obtained by a laboratory incubation technique, focuses on (a) NO production and consumption in sandy soils from two types of land use as function of soil temperature and soil moisture, and (b) The biogenic emission potential of nitric oxide from sandy soils in semi-arid region. At 25˚C, average NO production (in terms of mass of N) was 0.016,and 0.013 ng kg-1s-1 in sandy soils from soybean land (SL) and man-made forest (MF), re¬spectively. NO consumption rate constant ranged from 0.26×10-6 to 7.28×10-6 m3 kg-1s-1. At 25˚C and under optimum soil moisture conditions for NO production, the NO compensation point mixing ratio was about 266 and 161 ug m-3 (465,and 281 ppb) for soils of SL and MF, respectively. Statistically sound relationships have been observed between NO fluxes and soil moisture (optimum curves). NO fluxes also increased exponentially with soil temperature at any given soil moisture. The optimum soil moisture for which maximum NO flux was observed was independent of soil temperature. The maximum of NO flux potentials for SL and MF soils (at 25°C) were 59.6 and 36.5 ng m-2s-1 at water-filled pore space (%WFPS) of 26 and 24, respectively. The NO flux potential was about 2 times larger for cropland soil than for man-made forest soils, most likely due to fertilizer application to the cropland soils.

  1. Sandy Desertification Status and its Driving Mechanism in North Tibet Plateau

    Institute of Scientific and Technical Information of China (English)

    DONG Yuxiang

    2004-01-01

    As the main body of Qinghai-Tibetan Plateau, North Tibet Plateau is one of three major sandy desertification regions in China and also a representative sandy desertification zone of Qinghai-Tibet Plateau. Accordingly, it is an important region for the study of recent sandy desertification processes and formation mechanism. From such aspects as desertified land types, areas and distributions etc., this paper analyses in detail the sandy desertification status on North Tibet Plateau,and qualitatively and quantitatively deals with the main factors that affect recent sandy desertification processes and the driving mechanism. Research results show that North Tibet Plateau is an important sandy desertification region in China characterized with large desertified land areas, diversified types,high severity, extensive distributions and serious damages. Sandy desertification occurrence and development resulted from combined effects of natural factors, anthropogenic factors, natural processes and man-made processes, of which climatic change is the main driving force.

  2. Simulation of atrazine and metabolite transport and fate in a sandy-till aquifer

    Science.gov (United States)

    Levy, Jonathan; Chesters, Gordon

    1995-11-01

    In a 2.5-yr field study we determined the distribution of atrazine and its metabolites in a sandy-till aquifer overlying Cambrian sandstone in a dairy farming area. Flow paths are predominantly downward at piezometer nests where vertical hydraulic gradients dominate. Atrazine and desethylated atrazine concentrations along those flow paths generally decrease with increasing estimated groundwater travel time to the monitoring points. A one-dimensional contaminant transport model is developed in FORTRAN incorporating major chemical processes and dispersion along simulated flow paths. Separate simulations of atrazine and desethylated atrazine transport to individual piezometers are made, each with an appropriate average groundwater velocity. Regression equations are developed, based on an extensive literature review, to estimate acceptable sorption and dispersivity coefficients for the transport model. The one-dimensional simulations are calibrated using the field concentration-travel time relationships for atrazine and desethylated atrazine. The calibration procedure provides estimates of atrazine and desethylated atrazine degradation rates in groundwater corresponding to half-lives of 3470 and 2770 days, respectively. Although uncertain, the estimates provide evidence of much slower degradation in the aquifer than indicated by laboratory experiments. Using the calibrated transport parameter values, simulations of long-term steady-state leaching to the water table demonstrate that even with such slow degradation rates, steady-state concentrations at most piezometers are reached within ˜ 20 yr. Concentrations in the underlying sandstone aquifer are therefore not expected to increase substantially over time due to continued atrazine use. However, the slow degradation rates mean that even with the most optimistic condition, i.e. all input to the aquifer ceases in response to a cessation of atrazine application, it may take more than a decade for concentrations deeper in

  3. Using remote sensing and biogeographic modeling to understand the oak savannas of the Sheyenne National Grassland, North Dakota, USA

    Science.gov (United States)

    SigdelPhuyal, Mandira

    Oak savannas are valuable and complex ecosystems that provide multiple ecosystem goods and services, including grazing for livestock, watershed regulation, and recreation. These ecosystems of the woodland-prairie ecoregion of the Midwestern United States are, however, in danger of disappearing. The Sheyenne National Grassland, North Dakota, a protected Prairie grassland-savanna, is a representative of such rare habitats, where oak savanna is found at the landscape scale. In this research, I map the distribution patterns of oak savanna in the Sheyenne using a combination of remote sensing and geospatial datasets, including landscape topography, soils, and fire disturbance. Further, I interpret the performance of a suite of advanced Species Distribution Modeling approaches including Maximum Entropy, Random Forest, Generalized Boosted Model, and Classification Tree to analyze the primary environmental and management factors influencing oak distributions at landscape scales. Woody canopy cover was estimated with high classification accuracy (80-95%) for two study areas of the Sheyenne National Grassland. Among the four species distribution modeling approaches tested, the Random Forest (RF) approach provided the best predictive model. RF model parameters indicate that oak trees favor gently sloping locations, on well-drained upland and sandy soils, with north-facing aspect. While no direct data on water relationships were possible in this research, the importance of the topographic and soil variables in the SDM presumably reflect oak preference for locations and soils that are not prone to water saturation, with milder summer temperatures (i.e. northern aspects), providing conditions suitable for seedling establishment and growth. This research increases our understanding of the biogeography of Midwestern tall-grass oak savannas and provides a decision-support tool for oak savanna management.

  4. Remote Sensing Monitor of Grassland Desertification of Ruoergai County Based on 3S Technology%基于TM影像在若尔盖县草原沙化洞查中的应用研究

    Institute of Scientific and Technical Information of China (English)

    廖习红

    2012-01-01

    遥感及其技术应用和卫星技术的发展为资源环境调查提供了丰富的信息,在经济活动中发挥着巨大作用。本文根据美国陆地资源卫星TM影像特点,分析了若尔盖县草原沙4ETM影像色调特征,同时根据草原沙化在遥感影像上的特征,建立图像解译标志,获取若尔盖县草原沙化分布和面积情况。为进一步开展四川省草原沙化调查提供技术支持,为宏观决策者实施草原沙化治理提供科学依据。%Desertification of gassland is one of most serious environmental problems which is concerned all over the world. technology, With the support of 3S (remote sensing, geographic information system and global posmonmg system) remote sensing image i,~ used, including ground investigation. This paper analyses remote sensing monitor of sandy grasslan d in rergai county by establishing the model of remote sensing image and ground data. Based on the difference of tones and patterns, the image' s interpretation and classification index system have been established, the area and distribution and level of sandy grassland have been gained. The research finding gives further technical support to the sandy grassland of Sichuan province. At the same time, the data presents a scientific view for decision controlling grassland desertification.

  5. Quantifying the digital traces of Hurricane Sandy on Flickr.

    Science.gov (United States)

    Preis, Tobias; Moat, Helen Susannah; Bishop, Steven R; Treleaven, Philip; Stanley, H Eugene

    2013-11-05

    Society's increasing interactions with technology are creating extensive "digital traces" of our collective human behavior. These new data sources are fuelling the rapid development of the new field of computational social science. To investigate user attention to the Hurricane Sandy disaster in 2012, we analyze data from Flickr, a popular website for sharing personal photographs. In this case study, we find that the number of photos taken and subsequently uploaded to Flickr with titles, descriptions or tags related to Hurricane Sandy bears a striking correlation to the atmospheric pressure in the US state New Jersey during this period. Appropriate leverage of such information could be useful to policy makers and others charged with emergency crisis management.

  6. Long term BVOC fluxes above mountain grassland

    Directory of Open Access Journals (Sweden)

    I. Bamberger

    2010-01-01

    Full Text Available Grasslands comprise natural tropical savannah over managed temperate fields to tundra and cover over a quarter of the Earth's land surface. Plant growth, maintenance and decay result in volatile organic compound (VOCs emissions to the atmosphere. Furthermore, biogenic VOCs (BVOCs are emitted due to various environmental stresses including cutting and drying during harvesting. Fluxes of BVOCs were measured with a proton-transfer-reaction – mass-spectrometer (PTR-MS over temperate mountain grassland in Stubai Valley (Tyrol, Austria over one growing season (2008. VOC fluxes were calculated from the disjunct PTR-MS data using the virtual disjunct eddy covariance method and the gap filling method. The two independent methods obtained methanol fluxes following a regression line of y=0.94x−0.06 (correlation factor: R2=0.94. Methanol showed strong daytime emissions throughout the growing season. With maximal values of 9.7 nmol m−2 s−1 the methanol fluxes from growing grassland were considerably higher at the beginning of the growing season in June compared to those measured during October (2.5 nmol m−2 s−1. During the growth only methanol emissions were observed. The cutting and drying of the grass increased the emissions of methanol, up to 30 nmol m−2 s−2. In addition, emissions of acetaldehyde, up to 10 nmol m−2 s−1, and hexenal (leaf aldehyde were detected during harvesting.

  7. Difficulties of biomass estimation over natural grassland

    Science.gov (United States)

    Kertész, Péter; Gecse, Bernadett; Pintér, Krisztina; Fóti, Szilvia; Nagy, Zoltán

    2017-04-01

    Estimation of biomass amount in grasslands using remote sensing is a challenge due to the high diversity and different phenologies of the constituting plant species. The aim of this study was to estimate the biomass amount (dry weight per area) during the vegetation period of a diverse semi-natural grassland with remote sensing. A multispectral camera (Tetracam Mini-MCA 6) was used with 3 cm ground resolution. The pre-processing method includes noise reduction, the correction for the vignetting effect and the calculation of the reflectance using an Incident Light Sensor (ILS). Calibration was made with ASD spectrophotometer as reference. To estimate biomass Partial Least Squares Regression (PLSR) statistical method was used with 5 bands and NDVI as input variables. Above ground biomass was cut in 15 quadrats (50×50 cm) as reference. The best prediction was attained in spring (r2=0.94, RMSE: 26.37 g m-2). The average biomass amount was 167 g m-2. The variability of the biomass is mainly determined by the relief, which causes the high and low biomass patches to be stable. The reliability of biomass estimation was negatively affected by the appearance of flowers and by the senescent plant parts during the summer. To determine the effects of flower's presence on the biomass estimation, 20 dominant species with visually dominant flowers in the area were selected and cover of flowers (%) were estimated in permanent plots during measurement campaigns. If the cover of flowers was low (0,9), while at higher cover of flowers (>30%), the estimation failed (r2 <0,2). This effect restricts the usage of the remote sensing method to the spring - early summer period in diverse grasslands.

  8. Morphosedimentary evolution of carbonate sandy beaches at decadal scale : case study in Reunion Island , Indian Ocean

    Science.gov (United States)

    Mahabot, Marie-Myriam; Pennober, Gwenaelle; Suanez, Serge; Troadec, Roland; Delacourt, Christophe

    2017-04-01

    Global change introduce a lot of uncertainties concerning future trajectory of beaches by directly or indirectly modifying major driving factors. An improved understanding of the past shoreline evolution may help for anticipate future coastline response. However, in tropical environment, studies concerning carbonate beaches dynamics are scarce compared to open sandy beaches. Consequently, coral reef protected beaches morphological adjustment is still poorly understood and long-term evolution rate are poorly quantified in these specific environment. In this context, La Reunion Island, insular department of France located in Indian Ocean, constitute a favoured laboratory. This high volcanic island possesses 25 km of carbonate beaches which experience hydrodynamic forcing specific from tropical environment: cyclonic swell during summer and long period swell during winter. Because of degraded coral reef health and high anthropogenic pressure, 50% of the beaches are in erosion since 1970s. Beach survey has been conducted since 1990s by scientist and are now encompassed as pilot site within a French observatory network which guarantee long-term survey with high resolution observational techniques. Thus, La Reunion Island is one of the rare carbonate beach to be surveyed since 20 years. This study aims to examined and quantify beach response at decadal scale on carbonate sandy beaches of Reunion Island. The study focus on 12 km of beaches from Cap Champagne to the Passe de Trois-Bassins. The analyze of 15 beach profile data originated from historical and DGPS beach topographic data confirm long term trend to erosion. Sediment lost varies between 0.5 and 2 m3.yr-1 since 1998. However longshore current have led to accretion of some part of beach compartment with rate of 0.7 to 1.6 m3.yr-1. Wave climate was examined from in-situ measurement over 15 years and show that extreme waves associated with tropical cyclones and long period swell play a major role in beach dynamics

  9. Bioremediation potential of microorganisms from a sandy beach affected by a major oil spill.

    Science.gov (United States)

    Reis, Izabela; Almeida, C Marisa R; Magalhães, Catarina M; Cochofel, Jaqueline; Guedes, Paula; Basto, M Clara P; Bordalo, Adriano A; Mucha, Ana P

    2014-03-01

    The aim of this work was to evaluate the bioremediation potential of microorganisms from intertidal sediments of a sandy beach affected by a major oil spill 7 years before and subject to chronic petroleum contamination since then. For that, the response of microorganisms to a new oil contamination was assessed in terms of community structure, abundance, and capacity to degrade hydrocarbons. Experiments were carried out under laboratory-controlled conditions by mixing sediment with crude oil with three different nitrogen supplementations in 50 ml serum bottles under constant shake for 15 days. Autochthonous microorganisms were able to respond to the new oil contamination by increasing their abundance (quantified by DAPI) and changing the community structure (evaluated by DGGE). This response was particularly clear for some specific bacterial groups such as Pseudomonas, Actinomycetales, and Betaproteobacteria. These communities presented an important potential for hydrocarbon degradation (up to 85 % for TPHs and 70 % for total PAHs), being the biodegradation stimulated by addition of an appropriate amount of nitrogen.

  10. Methods for evaluation of the invasibility of grasslands

    DEFF Research Database (Denmark)

    Strandberg, M. T.; Strandberg, B.; Erneberg, M.

    The number of non-native plant species in Danish dry acidic grasslands was positively correlated with the cover of disturbance in the form of molehills, anthills, mouseholes and erosion due trampling or digging by large herbivores/livestock. Natural disturbance in acidic grassland ecosystems...

  11. Andean grasslands are as productive as tropical cloud forests

    NARCIS (Netherlands)

    Oliveras Menor, I.; Girardin, C.; Doughty, C.E.; Cahuana, N.; Arenas, C.E.; Oliver, V.; Huaraca Huasco, W.; Malhi, Y.

    2014-01-01

    We aim to assess net primary productivity (NPP) and carbon cycling in Andean tropical alpine grasslands (puna) and compare it with NPP of tropical montane cloud forests. We ask the following questions: (1) how do NPP and soil respiration of grasslands vary over the seasonal cycle? (2) how do burning

  12. Additional carbon sequestration benefits of grassland diversity restoration

    NARCIS (Netherlands)

    De Deyn, G.B.; Shiel, R.S.; Ostle, N.J.; McNamara, N.P.; Oakley, S.; Young, I.; Freeman, C.; Fenner, N.; Quirk, H.; Bardgett, R.D.

    2011-01-01

    1. In Europe, grassland agriculture is one of the dominant land uses. A major aim of European agri-environment policy is the management of grassland for botanical diversity conservation and restoration, together with the delivery of ecosystem services including soil carbon (C) sequestration. 2. To

  13. Additional carbon sequestration benefits of grassland diversity restoration

    NARCIS (Netherlands)

    Deyn, de G.B.; Shiel, R.S.; Ostle, N.J.; McNamara, N.P.; Oakley, S.; Young, I.; Freeman, C.; Fenner, N.; Quirk, H.; Bardgett, R.D.

    2011-01-01

    1. In Europe, grassland agriculture is one of the dominant land uses. A major aim of European agri-environment policy is the management of grassland for botanical diversity conservation and restoration, together with the delivery of ecosystem services including soil carbon (C) sequestration. 2. To

  14. Fungal/bacterial ratios in grassland with contrasting nitrogen management

    NARCIS (Netherlands)

    Vries, de F.T.; Hoffland, E.; Eekeren, van N.J.M.; Brussaard, L.; Bloem, J.

    2006-01-01

    It is frequently hypothesised that high soil fungal/bacterial ratios are indicative for more sustainable agricultural systems. Increased F / B ratios have been reported in extensively managed grasslands. To determine the shifts in fungal/bacterial biomass ratio as influenced by grassland management

  15. Considering Forest and Grassland Carbon in Land Management

    Science.gov (United States)

    M. Janowiak; W.J. Connelly;   K. Dante-Wood; G.M. Domke; C. Giardina; Z. Kayler; K. Marcinkowski; T. Ontl;   C. Rodriguez-Franco; C. Swanston; C.W. Woodall; M. Buford

    2017-01-01

    Forest and grassland ecosystems in the United States play a critical role in the global carbon cycle, and land management activities influence their ability to absorb and sequester carbon. These ecosystems provide a critical regulating function, offsetting about 12 to 19 percent of the Nation’s annual greenhouse gas emissions. Forests and grasslands are managed for...

  16. Wooded grasslands as part of the European agricultural heritage

    NARCIS (Netherlands)

    Centeri, C.; Renes, J.; Roth, M.; Kruse, A.; Eiter, S.; Kapfer, J.; Santoro, A.; Agnoletti, M.; Emanueli, , F.; Sigura, M.; Dobrovodska, M.; Štefunková, D.; Kučera, Zdeněk; Saláta, D.; Varga, Anna; Villacreces, S.; Dreer, J.; Slámová, M.

    2016-01-01

    Wooded grasslands have always played an important role in rural life with changing issues: They are of high importance for questions of biodiversity, soil, and water resources and in preserving agricultural heritage, but their maintenance is labor intensive. Abandoned wooded grasslands undergo succe

  17. Response of predominant soil bacteria to grassland succession

    NARCIS (Netherlands)

    Felske, A.

    1999-01-01

    The research described in this thesis was aimed to provide insight into the effects of grassland succession on the composition of the soil bacteria community in the Drentse A agricultural research area. The Drentse A meadows represent grassland succession at different stages. Since 30 years particul

  18. Dairy cow performance on silage from semi-natural grassland

    NARCIS (Netherlands)

    Bruinenberg, M.H.; Geerts, R.H.E.M.; Struik, P.C.; Valk, H.

    2006-01-01

    The effects of including forage from semi-natural grassland in the diet of dairy cows were studied in a feeding trial with cows in mid-lactation. Diets were compared in which part of the silage from intensively managed grassland was replaced with 0% (100IM), 20% (20SPP), 40% (40SPP) or 60% (60SPP)

  19. Quantifying the Digital Traces of Hurricane Sandy on Flickr

    OpenAIRE

    Preis, Tobias; Moat, Helen Susannah; Bishop, Steven R.; Treleaven, Philip; Stanley, H. Eugene

    2013-01-01

    Society’s increasing interactions with technology are creating extensive “digital traces” of our collective human behavior. These new data sources are fuelling the rapid development of the new field of computational social science. To investigate user attention to the Hurricane Sandy disaster in 2012, we analyze data from Flickr, a popular website for sharing personal photographs. In this case study, we find that the number of photos taken and subsequently uploaded to Flickr with titles, desc...

  20. Brazilian sandy beaches: characteristics, ecosystem services, impacts, knowledge and priorities

    Directory of Open Access Journals (Sweden)

    Antonia Cecília Zacagnini Amaral

    Full Text Available ABSTRACT Sandy beaches constitute a key ecosystem and provide socioeconomic goods and services, thereby playing an important role in the maintenance of human populations and in biodiversity conservation. Despite the ecological and social importance of these ecosytems, Brazilian sandy beaches are significantly impacted by human interference, chemical and organic pollution and tourism, as well as global climate change. These factors drive the need to better understand the environmental change and its consequences for biota. To promote the implementation of integrated studies to detect the effects of regional and global environmental change on beaches and on other benthic habitats of the Brazilian coast, Brazilian marine researchers have established The Coastal Benthic Habitats Monitoring Network (ReBentos. In order to provide input for sample planning by ReBentos, we have conducted an intensive review of the studies conducted on Brazilian beaches and summarized the current knowledge about this environment. In this paper, we present the results of this review and describe the physical, biological and socioeconomics features of Brazilian beaches. We have used these results, our personal experience and worldwide literature to identify research projects that should be prioritized in the assessment of regional and global change on Brazilian sandy beaches. We trust that this paper will provide insights for future studies and represent a significant step towards the conservation of Brazilian beaches and their biodiversity.

  1. Hurricane Sandy washover deposits on Fire Island, New York

    Science.gov (United States)

    La Selle, SeanPaul M.; Lunghino, Brent D.; Jaffe, Bruce E.; Gelfenbaum, Guy; Costa, Pedro J.M.

    2017-02-16

    Washover deposits on Fire Island, New York, from Hurricane Sandy in 2012 were investigated a year after the storm to document the sedimentary characteristics of hurricane washover features. Sediment data collected in the field includes stratigraphic descriptions and photos from trenches, bulk sediment samples, U-channels, and gouge and push cores. Samples and push cores were further analyzed in the laboratory for grain size, density variations using x-ray computed tomography (CT), and surface microtexture using a scanning electron microscope (SEM). Elevation profiles of washover features were measured using Differential Global Positioning System (DGPS) with Real Time Kinematic processing. The DGPS elevations were compared to lidar (light detection and ranging) data from pre- and post-Sandy surveys to assess the degree to which washover deposit thicknesses changed within the year following deposition. Hurricane Sandy washover deposits as much as 1 meter thick were observed in trenches. Initial results show that the upper parts of the deposits have been reworked significantly in some places by wind, but there are still areas where the deposits are almost entirely intact. Where mostly intact, the washover deposits consist of massive or weakly laminated sand near the base, overlain by more strongly laminated sands.

  2. On the Fossil Pediastrum from the Gaoximage Section, Hunshandak Sandy Land and Its Ecological Significance Since 5 000 a BP

    Institute of Scientific and Technical Information of China (English)

    XUZhao-Liang; LIChun-Yu; KONGZhao-Chen

    2004-01-01

    The fossil Pediastrum was investigated from the Gaoximage section ( 42°57′14″ N, 115°22′3″E, Air 1 253 m ) in the Hunshandak Sandy Land, Inner Mongolia (Nei Mongol) of China in order to gain a better understanding the changes of palaeovegetation, palaeoenvironment and palaeoclimite since 5000 aBP when the pollen-spore was studied. The results show that the fossil Pediastrum assemblage can be divided into three periods: Ⅰ. 5 000-3 500 a BP, the fossil Pediastrum occurred rarely. Based on this result it can be surmised that the lake might be fresh water with poor organics. Ⅱ. 3 500-1 500 a BP, the fossil Pediastrum likes volcanic emerged. It probably indicate moist conditions and the grasslands were developed during this time; and Ⅲ. 1 500-200 a BP, the fossil Pediastrum disappeared. It can show that the lake water become salty and shrunk, and the weather could become drier and drier. This result shows that Pediastrurn, a kind of facies fossil, happened simultaneously in the pollen-spore assemblage during the second period. Sometimes Pediastrurncan reach more than 60 per cent of the total spore pollen assemblage, indicating that Gaoximage lake was not only fresh water with abundant eutrophic materials but also occupied a large area during 3 500-1 500 a BP.

  3. Optimising stocking rate and grazing management to enhance environmental and production outcomes for native temperate grasslands

    Science.gov (United States)

    Badgery, Warwick; Zhang, Yingjun; Huang, Ding; Broadfoot, Kim; Kemp, David; Mitchell, David

    2015-04-01

    Stocking rate and grazing management can be altered to enhance the sustainable production of grasslands but the relative influence of each has not often been determined for native temperate grasslands. Grazing management can range from seasonal rests through to intensive rotational grazing involving >30 paddocks. In large scale grazing, it can be difficult to segregate the influence of grazing pressure from the timing of utilisation. Moreover, relative grazing pressure can change between years as seasonal conditions influence grassland production compared to the relative constant requirements of animals. This paper reports on two studies in temperate native grasslands of northern China and south eastern Australia that examined stocking rate and regionally relevant grazing management strategies. In China, the grazing experiment involved combinations of a rest, moderate or heavy grazing pressure of sheep in spring, then moderate or heavy grazing in summer and autumn. Moderate grazing pressure at 50% of the current district average, resulted in the better balance between maintaining productive and diverse grasslands, a profitable livestock system, and mitigation of greenhouse gases through increased soil carbon, methane uptake by the soil, and efficient methane emissions per unit of weight gain. Spring rests best maintained a desirable grassland composition, but had few other benefits and reduced livestock productivity due to lower feed quality from grazing later in the season. In Australia, the grazing experiment compared continuous grazing to flexible 4- and 20-paddock rotational grazing systems with sheep. Stocking rates were adjusted between systems biannually based on the average herbage mass of the grassland. No treatment degraded the perennial pasture composition, but ground cover was maintained at higher levels in the 20-paddock system even though this treatment had a higher stocking rate. Overall there was little difference in livestock production (e.g. kg

  4. Impacts of climate and management on water balance and nitrogen leaching from montane grassland soils

    Science.gov (United States)

    Fu, Jin; Gasche, Rainer; Wang, Na; Lu, Haiyan; Butterbach-Bahl, Klaus; Kiese, Ralf

    2017-04-01

    . Moreover, plant uptake was often exceeding slurry application rates, suggesting further supply of N due to soil organic matter decomposition. The low risk of nitrate leaching of cut grassland on non-sandy soils with vigorous grass growth may call for a careful re-evaluation of the maximum fertilization rate of 250 kg N ha-1 as defined by the EU Nitrate and Water Framework Directive.

  5. On the Relationship between Economic Development, Environmental Integrity and Well-Being: The Point of View of Herdsmen in Northern China Grassland.

    Science.gov (United States)

    Dong, Xiaobin; Dai, Guangshuo; Ulgiati, Sergio; Na, Risu; Zhang, Xinshi; Kang, Muyi; Wang, Xuechao

    2015-01-01

    Inner Mongolia is among the most important regions in terms of contribution to the socio-economic development of China. Furthermore, its grassland is a major ecological barrier for Northern China. The present study evaluates the changes in ecosystem services availability and human wellbeing based on a survey on864 herdsmen of the grassland and 20 governmental officials. The survey provided the following results: (1) The supporting and provisioning services of the grassland have recently declined, thus affecting the herdsmen's wellbeing. The intensity of grazing, coal exploitation and tourism development heavily limits the availability of ecosystem services, among which provisioning ones are perceived as the most important. Below a certain threshold, grazing and mining are likely to promote the improvement of herdsmen's wellbeing, while trespassing that point, the enhancement of the herdsmen's living standards is curbed. (2) The herdsmen's cultural exchange, health conditions and social relations are better now than before; however, the threats on herdsmen's health and safety have increased. (3) A better income is among the most urgent herdsmen's needs. Livestock revenues did not increase at the same rate as the damage to the grassland and human risk exposure did. (4) The governmental ecological compensation policy did not entirely solve the problem of grassland desertification and environmental degradation, although it is also true that the degree of implementation and effectiveness of government policies is related to the still insufficient herdsmen's understanding and acceptance of these policies.

  6. Methanol exchange between grassland and the atmosphere

    Directory of Open Access Journals (Sweden)

    A. Brunner

    2007-01-01

    Full Text Available Concentrations and fluxes of methanol were measured above two differently managed grassland fields (intensive and extensive in central Switzerland during summer 2004. The measurements were performed with a proton-transfer-reaction mass-spectrometer and fluxes were determined by the eddy covariance method. The observed methanol emission showed a distinct diurnal cycle and was strongly correlated with global radiation and water vapour flux. Mean and maximum daily emissions were found to depend on grassland species composition and, for the intensive field, also on the growing state. The extensive field with a more complex species composition had higher emissions than the graminoid-dominated intensive field, both on an area and on a biomass basis. A simple parameterisation depending on the water vapour flux and the leaf area index allowed a satisfying simulation of the temporal variation of methanol emissions over the growing phase. Accumulated carbon losses due to methanol emissions accounted for 0.024 and 0.048% of net primary productivity for the intensive and extensive field, respectively. The integral methanol emissions over the growing periods were more than one order of magnitude higher than the emissions related to cut and drying events.

  7. Soil phosphorus constrains biodiversity across European grasslands.

    Science.gov (United States)

    Ceulemans, Tobias; Stevens, Carly J; Duchateau, Luc; Jacquemyn, Hans; Gowing, David J G; Merckx, Roel; Wallace, Hilary; van Rooijen, Nils; Goethem, Thomas; Bobbink, Roland; Dorland, Edu; Gaudnik, Cassandre; Alard, Didier; Corcket, Emmanuel; Muller, Serge; Dise, Nancy B; Dupré, Cecilia; Diekmann, Martin; Honnay, Olivier

    2014-12-01

    Nutrient pollution presents a serious threat to biodiversity conservation. In terrestrial ecosystems, the deleterious effects of nitrogen pollution are increasingly understood and several mitigating environmental policies have been developed. Compared to nitrogen, the effects of increased phosphorus have received far less attention, although some studies have indicated that phosphorus pollution may be detrimental for biodiversity as well. On the basis of a dataset covering 501 grassland plots throughout Europe, we demonstrate that, independent of the level of atmospheric nitrogen deposition and soil acidity, plant species richness was consistently negatively related to soil phosphorus. We also identified thresholds in soil phosphorus above which biodiversity appears to remain at a constant low level. Our results indicate that nutrient management policies biased toward reducing nitrogen pollution will fail to preserve biodiversity. As soil phosphorus is known to be extremely persistent and we found no evidence for a critical threshold below which no environmental harm is expected, we suggest that agro-environmental schemes should include grasslands that are permanently free from phosphorus fertilization.

  8. Effects of grazing on leaf traits and ecosystem functioning in Inner Mongolia grasslands: scaling from species to community

    Directory of Open Access Journals (Sweden)

    S. X. Zheng

    2009-10-01

    prevent grassland degradation.

  9. Controls on microbial accessibility to soil organic carbon following woody plant encroachment into grasslands

    Science.gov (United States)

    Creamer, Courtney; Boutton, Thomas; Olk, Dan; Filley, Timothy

    2010-05-01

    Woody plant encroachment (WPE) into savannas and grasslands is a global phenomenon that alters soil organic carbon (SOC) dynamics through changes in litter quality and quantity, soil structure, microbial ecology, and hydrology. To elucidate the controls on microbial accessibility to SOC, bulk soils from a chronosequence of progressive WPE into native grasslands at the Texas Agrilife La Copita Research Area were incubated for one year. The quantity and stable carbon isotope composition of respired CO2, and plant biopolymer chemistry in SOC were tracked. Respiration rates declined exponentially over the course of the experiment with 15-25% of the total CO2 respired released in the first month of incubation. Between 8 and 18% of the total SOC was mineralized to CO2 throughout the incubation. After day 84 a significantly (pproductivity. Despite documented SOC accrual following WPE at La Copita, we observed no evidence of enhanced SOC stabilization in these respiration experiments. In fact, a greater proportion of total SOC was lost from the soil of mature woody stands than from young stands, suggesting SOC accumulation observed with WPE may be due to greater input rates or microbial dynamics not captured in the laboratory incubation. Compound-specific analyses indicated there was a significant (pamino acids, and amino sugars during the incubation. Amino nitrogen tended to become more concentrated during the incubation, although the trend was not significant. Relatively few significant trends of these compounds in response to woody stand age were observed, indicating that these compounds were generally degraded to the same extent during the incubation. We hypothesize that biochemical recalcitrance is not an important mechanism for the stabilization of SOC at this site. By day 184 of the incubation, CO2 respired from older woody clusters (34-86 years) was significantly (p<0.05) less 13C-depleted with respect to bulk SOC than CO2 respired from younger woody clusters (14

  10. Response of a keystone rodent to landscape-scale restoration of desert grasslands

    Science.gov (United States)

    Over the last century, many grasslands in the Chihuahuan Desert have converted to shrublands dominated by creosotebush (Larrea tridentata). The loss and spatial isolation of perennial grasslands has led to declines of grassland-dependent wildlife species. Grassland restoration efforts have been domi...

  11. Poverty, population and environmental degradation in China.

    Science.gov (United States)

    Rozelle, S; Huang, J; Zhang, L

    1997-06-01

    This article examines the relationship between poverty, population, and environmental degradation in China. Environmental conditions include water pollution, deforestation, destruction of grasslands, soil erosion, and salinization. The authors review China's success in controlling environmental degradation through leadership, environmental policies, and institutional capacity. Findings suggest that environmental progress is best achieved indirectly by poverty alleviation, market integration, and population control. Government policies were not very effective. Degradation occurs due to limited financial resources, poorly trained personnel, and political factors. Control of water pollution was instituted since the 1980s. The levels of pollutants have been reduced, but the type of pollutant determines the seriousness of impact. Water pollution is due to industrial wastes, agricultural run-off, and soil erosion. Since the 1970s, reforestation targets have not been met. Technical extension and monitoring of planting is not available in most areas, and private, profit seeking interests control acreage. Grassland destruction is due to deforestation, agricultural expansion, and overgrazing. Independent regional authorities have successfully managed pasture programs. Erosion is the most serious in Loess Plateau, the Red Soils area, the Northeast China Plain, and the Northwest Grasslands, which comprise 70% of total land area. In 1990, erosion control was practiced in 39% of eroded land area. Salinization has remained fairly constant. Environmental controls (direct regulation, planned recovery, and state-mandated technological improvements) are uneven. The main tool for environmental management is the State Environmental Protection Commission and its executive unit, SEPA. Problems stem from vague laws, lack of means of enforcement, lack of coordination of laws, and lack of standards, schedules, and other provisions in ordinances.

  12. Water level response in back-barrier bays unchanged following Hurricane Sandy

    Science.gov (United States)

    Aretxabaleta, Alfredo L.; Butman, Bradford; Ganju, Neil K.

    2014-01-01

    On 28–30 October 2012, Hurricane Sandy caused severe flooding along portions of the northeast coast of the United States and cut new inlets across barrier islands in New Jersey and New York. About 30% of the 20 highest daily maximum water levels observed between 2007 and 2013 in Barnegat and Great South Bay occurred in 5 months following Hurricane Sandy. Hurricane Sandy provided a rare opportunity to determine whether extreme events alter systems protected by barrier islands, leaving the mainland more vulnerable to flooding. Comparisons between water levels before and after Hurricane Sandy at bay stations and an offshore station show no significant differences in the transfer of sea level fluctuations from offshore to either bay following Sandy. The post-Hurricane Sandy bay high water levels reflected offshore sea levels caused by winter storms, not by barrier island breaching or geomorphic changes within the bays.

  13. Grasslands feeling the heat: The effects of elevated temperatures on a subtropical grassland

    Directory of Open Access Journals (Sweden)

    Rowan D. Buhrmann

    2016-11-01

    Full Text Available Background: Tropical and subtropical Africa is predicted to experience a rise in temperature. The effects of rising temperatures on temperate grasslands have been studied using open-top chambers (OTCs but reports for tropical/subtropical grasslands are scarce. This study used OTCs to investigate the effects of elevated temperatures on a threatened subtropical grassland type, namely KwaZulu-Natal Sandstone Sourveld (KZNSS.Objectives: To assess the effects of OTCs on selected abiotic parameters and plant productivity within KZNSS.Methods: Five OTC and control plots were randomly distributed at the same altitude within a patch of KZNSS. Air and soil temperature, relative humidity (RH, soil moisture content and light intensity were monitored in all plots in spring, summer, autumn and winter. Biomass production and plant density were measured in each season, for each life form (graminoid, forb and shrub, separately and combined.Results: The OTCs resulted in a rise in average, maximum and minimum day and night, air and soil temperatures. This increase, the degree of which differed across seasons, was accompanied by a decline in RH and soil moisture content. Elevated temperatures led to a significant increase in combined, graminoid and shrub above-ground productivity (AGP and a decrease in forb density, but in certain seasons only. Below-ground biomass production was unaffected by elevated temperatures.Conclusions: OTCs can simulate realistic increases of air temperature in subtropical grasslands. Graminoids and shrubs appear to benefit from elevated temperatures whilst forbs decrease in abundance, possibly through competition and/or direct physiological effects.

  14. Online Media Use and Adoption by Hurricane Sandy Affected Fire and Police Departments

    OpenAIRE

    Chauhan, Apoorva

    2014-01-01

    In this thesis work, I examine the use and adoption of online communication media by 840 fire and police departments that were affected by the 2012 Hurricane Sandy. I began by exploring how and why these fire and police departments used (or did not use) online media to communicate with the public during Hurricane Sandy. Results show that fire and police departments used online media during Hurricane Sandy to give timely and relevant information to the public about things such as evacuations, ...

  15. Morphology of rain water channelization in systematically varied model sandy soils

    OpenAIRE

    Wei, Y.; Cejas, C. M.; Barrois, R.; Dreyfus, R.; Durian, D. J.

    2014-01-01

    We visualize the formation of fingered flow in dry model sandy soils under different raining conditions using a quasi-2d experimental set-up, and systematically determine the impact of soil grain diameter and surface wetting property on water channelization phenomenon. The model sandy soils we use are random closely-packed glass beads with varied diameters and surface treatments. For hydrophilic sandy soils, our experiments show that rain water infiltrates into a shallow top layer of soil and...

  16. Longitudinal Impact of Hurricane Sandy Exposure on Mental Health Symptoms

    Directory of Open Access Journals (Sweden)

    Rebecca M. Schwartz

    2017-08-01

    Full Text Available Hurricane Sandy hit the eastern coast of the United States in October 2012, causing billions of dollars in damage and acute physical and mental health problems. The long-term mental health consequences of the storm and their predictors have not been studied. New York City and Long Island residents completed questionnaires regarding their initial Hurricane Sandy exposure and mental health symptoms at baseline and 1 year later (N = 130. There were statistically significant decreases in anxiety scores (mean difference = −0.33, p < 0.01 and post-traumatic stress disorder (PTSD scores (mean difference = −1.98, p = 0.001 between baseline and follow-up. Experiencing a combination of personal and property damage was positively associated with long-term PTSD symptoms (ORadj 1.2, 95% CI [1.1–1.4] but not with anxiety or depression. Having anxiety, depression, or PTSD at baseline was a significant predictor of persistent anxiety (ORadj 2.8 95% CI [1.1–6.8], depression (ORadj 7.4 95% CI [2.3–24.1 and PTSD (ORadj 4.1 95% CI [1.1–14.6] at follow-up. Exposure to Hurricane Sandy has an impact on PTSD symptoms that persists over time. Given the likelihood of more frequent and intense hurricanes due to climate change, future hurricane recovery efforts must consider the long-term effects of hurricane exposure on mental health, especially on PTSD, when providing appropriate assistance and treatment.

  17. Surging wildfire activity in a grassland biome

    Science.gov (United States)

    Donovan, Victoria M.; Wonkka, Carissa L.; Twidwell, Dirac

    2017-06-01

    Rapid changes in wildfire patterns are documented globally, increasing pressure to identify regions that may experience increases in wildfire in future decades. Temperate grassland and savanna biomes were some of the most frequently burned regions on Earth; however, large wildfires have been largely absent from the Great Plains of North America over the last century. In this paper, we conduct an in-depth analysis of changes in large wildfire (>400 ha) regime characteristics over a 30 year period across the Great Plains. For the entire biome, (i) the average number of large wildfires increased from 33.4 ± 5.6 per year from 1985 to 1994 to 116.8 ± 28.8 wildfires per year from 2005 to 2014, (ii) total area burned by large wildfires increased 400%, (iii) over half the ecoregions had greater than a 70% probability of a large wildfire occurring in the last decade, and (iv) seasonality of large wildfires remained relatively similar.

  18. Emergency evacuation orders: considerations and lessons from Hurricane Sandy.

    Science.gov (United States)

    O'Neil, Patrick D

    2014-01-01

    This article analyzes the problems surrounding the execution of emergency evacuation orders by evaluating Hurricane Sandy and the emergency actions taken by the State of New Jersey and the City of Atlantic City New Jersey. The analysis provides an overview of the legal authority granting emergency powers to governors and mayors to issue evacuation proclamations in addition to an evaluation of the New Jersey's emergency evacuation mandate and subsequent compliance. The article concludes with provision of planning and preparedness recommendations for public managers facing similar hazards, including a recommendation for provision of emergency shelter contingencies within the threat zone in anticipation of citizen noncompliance evacuation orders.

  19. Uncertainties in sandy shorelines evolution under the Bruun rule assumption

    Directory of Open Access Journals (Sweden)

    Gonéri eLe Cozannet

    2016-04-01

    Full Text Available In the current practice of sandy shoreline change assessments, the local sedimentary budget is evaluated using the sediment balance equation, that is, by summing the contributions of longshore and cross-shore processes. The contribution of future sea-level-rise induced by climate change is usually obtained using the Bruun rule, which assumes that the shoreline retreat is equal to the change of sea-level divided by the slope of the upper shoreface. However, it remains unsure that this approach is appropriate to account for the impacts of future sea-level rise. This is due to the lack of relevant observations to validate the Bruun rule under the expected sea-level rise rates. To address this issue, this article estimates the coastal settings and period of time under which the use of the Bruun rule could be (invalidated, in the case of wave-exposed gently-sloping sandy beaches. Using the sedimentary budgets of Stive (2004 and probabilistic sea-level rise scenarios based on IPCC, we provide shoreline change projections that account for all uncertain hydrosedimentary processes affecting idealized coasts (impacts of sea-level rise, storms and other cross-shore and longshore processes. We evaluate the relative importance of each source of uncertainties in the sediment balance equation using a global sensitivity analysis. For scenario RCP 6.0 and 8.5 and in the absence of coastal defences, the model predicts a perceivable shift toward generalized beach erosion by the middle of the 21st century. In contrast, the model predictions are unlikely to differ from the current situation in case of scenario RCP 2.6. Finally, the contribution of sea-level rise and climate change scenarios to sandy shoreline change projections uncertainties increases with time during the 21st century. Our results have three primary implications for coastal settings similar to those provided described in Stive (2004 : first, the validation of the Bruun rule will not necessarily be

  20. Remediation of Diesel Fuel Contaminated Sandy Soil using Ultrasonic Waves

    Directory of Open Access Journals (Sweden)

    Wulandari P.S.

    2010-01-01

    Full Text Available Ultrasonic cleaning has been used in industry for some time, but the application of ultrasonic cleaning in contaminated soil is just recently received considerable attention, it is a very new technique, especially in Indonesia. An ultrasonic cleaner works mostly by energy released from the collapse of millions of microscopic cavitations near the dirty surface. This paper investigates the use of ultrasonic wave to enhance remediation of diesel fuel contaminated sandy soil considering the ultrasonic power, soil particle size, soil density, water flow rate, and duration of ultrasonic waves application.

  1. 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.

  2. The Canopy Conductance of a Humid Grassland

    Science.gov (United States)

    Lu, C. T.; Hsieh, C. I.

    2015-12-01

    Penman-Monteith equation is widely used for estimating latent heat flux. The key parameter for implementing this equation is the canopy conductance (gc). Recent research (Blaken and Black, 2004) showed that gc could be well parameterized by a linear function of An/ (D0* X0c), where An represents net assimilation, D0 is leaf level saturation deficit, and X0c is CO2 mole fraction. In this study, we tried to use the same idea for estimating gcfor a humid grassland. The study site was located in County Cork, southwest Ireland (51o59''N 8o46''W), and perennial ryegrass (Lolium perenne L.) was the dominant grass species in this area. An eddy covariance system was used to measure the latent heat flux above this humid grassland. The measured gc was calculated by rearranging Penman-Monteith equation combined with the measured latent heat flux. Our data showed that the gc decreased as the vapor pressure deficit and temperature increased. And it increased as the net radiation increased. Therefore, we found out that the best parameterization of gc was a linear function of the product of the vapor deficit, temperature, and net radiation. Also, we used the gc which was estimated by this linear function to predict the latent heat flux by Penman-Monteith equation and compared the predictions with those where the gc was chosen to be a fixed value. Our analysis showed that this simple linear function for gc can improve the latent heat flux predictions (R square increased from 0.48 to 0.66).

  3. 草原退化过程中植物群落的结构异质性分析--以家庭牧场为例%Analysis of Plant Community Structure Heterogeneity in The Process of Grassland Degradation---Taking Household Pasture for an Example

    Institute of Scientific and Technical Information of China (English)

    乌云娜; 霍光伟; 宋彦涛; 张凤杰

    2015-01-01

    This study took a household pasture on the Hulunbeir grassland as research scale, and the method of space succession series instead of time series of succession series was used to anal-ysis plant community structure heterogeneity. Setting the sheepfold as the center of the house-hold pasture,we divided the household pasture into heavy grazing area, moderate grazing area, light grazing area and non-grazing area(fence inside), and at the same time setting a village free grazing area ( i. e. over-grazing area) for comparison. The results showed that the house-hold pasture had kinds of plant species, mostly plant species were perennial herbs, and the ratio of annual herbs increased with the grazing intensity reducing. The light grazing area had the highest aboveground biomass, thus, a light grazing disturbance could contribute to the increase of plant dry matter. Compared the household pasture with the over grazing area, the importance value of Poaceae plants in the light grazing area were higher than other areas, indicating that a light grazing disturbance conducived to the communities in restoration succession. Simpson in-dex, Shannon-Wiener index and Pielou evenness index of heavy grazing area and light grazing area were higher than that of the over grazing area. Plant communities of the heavy grazing area and the light grazing area had reached a more stable state due to competition. The spatial hetero-geneity of plant community was higher in more concentrated of plant communities.%以内蒙古呼伦贝尔草原某家庭牧场作为研究尺度,以卧羊圈为中心沿辐射状将该家庭牧场划分为重牧区、中牧区、轻牧区和无牧区(围栏内),同时与村落自由放牧区(即过牧区)进行比较,开展植物群落结构空间异质性研究。结果表明:该家庭牧场植物群落种类较为丰富,多年生草本植物居多,一年生草本植物随放牧强度的减弱,比例也随之增加;轻牧条件

  4. Grassland communities of urban open spaces in Bloemfontein, Free State, South Africa

    Directory of Open Access Journals (Sweden)

    Mamokete N.V. Dingaan

    2013-02-01

    Full Text Available Natural vegetation in urban environments is greatly impacted by human activities and it is in constant threat of degradation and destruction as a result of urbanisation. This vegetation, although fragmented, serves an important ecological function and needs to be properly managed and conserved. Studies on urban vegetation are lacking in South Africa, with only a handful having been carried out since the end of the last century. This study was initiated to identify, classify and describe the grassland communities of the urban open spaces in Bloemfontein. Relevés were compiled in 61 sample plots, where species present and habitat information were recorded. Care was taken to restrict sample plots to vegetation in pristine condition, wherever possible, and severely degraded stands were avoided. A two-way indicator species analysis (TWINSPAN classification, refined by Braun-Blanquet procedures, revealed two distinct major communities, seven communities and four sub-communities. Both detrended and canonical correspondence analyses indicated the vegetation units to be associated with soil texture and pH, although biotic factors such as overgrazing, burning and mowing also influence the composition of the vegetation. The proper management and conservation of urban open spaces requires in-depth knowledge of the spatial distribution, floristic, structural and functional compositions within the major vegetation types in this environment. The present study further contributed towards formulating ways for the proper management, utilisation and functioning of the open spaces within the Bloemfontein area.Conservation implications: The Grassland Biome of South Africa is poorly conserved, mainly because of its status as an agricultural hub of the country. The preservation of natural and semi-natural forms of urban vegetation is important because such vegetation, although often disturbed and degraded, could form dispersal corridors between peri-urban and rural

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

    Science.gov (United States)

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

    2010-03-01

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

  6. Spatio-temporal effects of low severity grassland fire on soil colour

    Science.gov (United States)

    Pereira, Paulo; Cerdà, Artemi; Bolutiene, Violeta; Pranskevicius, Mantas; Úbeda, Xavier; Jordán, Antonio; Zavala, Lorena; Mataix-Solera, Jorge

    2013-04-01

    Fire changes soil properties directly, through temperature, or indirectly with ash deposition and the temporal elimination of vegetal cover. Both influences change soil colour and soil properties. The degree of changes depends on fire severity that has important implications on soil organic matter, texture, mineralogy and hydrological properties and type of ash produced. The ash colour is different according to the temperature of combustion and burned specie and this property will have implications on soil colour. In addition, ash properties have a strong spatial variability. The aim of this work is to study the spatio-temporal effects of a low severity grassland fire on soil colour occurred in Lithuania, near Vilnius city (54° 42' N, 25° 08' E, 158 m.a.s.l.). After the fire it was designed a plot of 20x20m in a burned and unburned flat area. Soil colour was analysed immediately after the fire, and 2, 5, 7 and 9 months after the fire. In each sampling 25 soil samples were collected, carried out to the laboratory, dried at room temperature (20-24° C) and sieved with the Mataix-Solera, J. Arcenegui, V., Zavala, L. (2013a) Modelling the impacts of wildfire on ash thickness in a short-term period, Land Degradation and Development (In press) DOI: 10.1002/ldr.2195 Pereira, P., Cerdà, A., Úbeda, X., Mataix-Solera, J., Martin, D.A., Jordan, A. Burguet, M. (2013b) Effects of fire on ash thickness in a Lithuanian grassland and short-term spatio-temporal changes. Solid Earth Discussions, 4 (1), 1545-1584. doi:10.5194/sed-4-1-2012 Pereira, P., Pranskevicius, M., Cepanko, V., Vaitkute, D., Pundyte, N., Ubeda, X., Mataix-Soler, J., Cerda, A., Martin, D.A. (2013c) Short time vegetation recovers after a spring grassland fire in Lithuania. Temporal and slope position effect, Flamma, 4(1), 13-17.

  7. Modeling Wood Encroachment in Abandoned Grasslands in the Eifel National Park - Model Description and Testing.

    Directory of Open Access Journals (Sweden)

    Silvana Hudjetz

    Full Text Available The degradation of natural and semi-natural landscapes has become a matter of global concern. In Germany, semi-natural grasslands belong to the most species-rich habitat types but have suffered heavily from changes in land use. After abandonment, the course of succession at a specific site is often difficult to predict because many processes interact. In order to support decision making when managing semi-natural grasslands in the Eifel National Park, we built the WoodS-Model (Woodland Succession Model. A multimodeling approach was used to integrate vegetation dynamics in both the herbaceous and shrub/tree layer. The cover of grasses and herbs was simulated in a compartment model, whereas bushes and trees were modelled in an individual-based manner. Both models worked and interacted in a spatially explicit, raster-based landscape. We present here the model description, parameterization and testing. We show highly detailed projections of the succession of a semi-natural grassland including the influence of initial vegetation composition, neighborhood interactions and ungulate browsing. We carefully weighted the single processes against each other and their relevance for landscape development under different scenarios, while explicitly considering specific site conditions. Model evaluation revealed that the model is able to emulate successional patterns as observed in the field as well as plausible results for different population densities of red deer. Important neighborhood interactions such as seed dispersal, the protection of seedlings from browsing ungulates by thorny bushes, and the inhibition of wood encroachment by the herbaceous layer, have been successfully reproduced. Therefore, not only a detailed model but also detailed initialization turned out to be important for spatially explicit projections of a given site. The advantage of the WoodS-Model is that it integrates these many mutually interacting processes of succession.

  8. Crop and Grassland Management Plan : Mingo National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Mingo NWR Crop and Grassland Management Plan focuses on the production of supplemental grain and browse foods to maintain wildlife populations. In addition,...

  9. Grassland Management Plan Erie National Wildlife Refuge 1981

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This management plan provides well defined guidelines to accomplish the following goals at Erie National Wildlife Refuge : 1) to manage existing grasslands, 2)...

  10. Grasslands Wildlife Management Area : Annual narrative report : Calendar year 1991

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Grasslands WMA outlines Refuge accomplishments during the 1991 calendar year. The report begins with a summary of the year's...

  11. Soil Organic Carbon Responses to Forest Expansion on Mountain Grasslands

    DEFF Research Database (Denmark)

    Guidi, Claudia

    Grassland abandonment followed by progressive forest expansion is the dominant land-use change in the European Alps. Contrasting trends in soil organic carbon (SOC) stocks have been reported for mountainous regions following forest expansion on grasslands. Moreover, its effects on SOC properties...... involved into long-term stability are largely unknown. The aim of this PhD thesis was to explore changes in: (i) SOC stocks; (ii) physical SOC fractions; and (iii) labile soil carbon components following forest expansion on mountain grasslands. A land-use gradient located in the Southern Alps (Italy....... Changes in labile soil C were assessed by carbohydrate and thermal analyses of soil samples and fractions. Forest expansion on mountain grasslands caused a decrease in SOC stocks within the mineral soil. The SOC accumulation within the organic layers following forest establishment could not fully...

  12. Louisa District Mark Twain NWR : Grassland Management Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Mark Twain National Wildlife Refuge- Louisa District Grassland Management Plan addresses management strategies to provide habitat and food for waterfowl and...

  13. Shawangunk Grasslands National Wildlife Refuge: Comprehensive Conservation Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Comprehensive Conservation Plan (CCP) was written to guide management on Shawangunk Grasslands NWR for the next 15 years. This plan outlines the Refuge vision...

  14. Project kicks off for the recovery of depleted frigid grasslands

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ A research project on the reclaiming technology for degenerated ecosystems on alpine & frigid grasslands was launched on 19 April at the CAS Northwest Institute of Plateau Biology (NIPB) in Lanzhou.

  15. Grassland Management Plan : Big Stone National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The grassland management objectives for Big Stone National Wildlife Refuge are: (1) to provide secure nesting cover for ground nesting waterfowl. The refuge...

  16. Grassland Management Plan Missisquoi National Wildlife Refuge 1986

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This management plan provides well defined guidelines to accomplish the following goals: (1) to continue to improve existing grasslands for nesting waterfowl,...

  17. Grassland Management Plan Wertheim National Wildlife Refuge 1989

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This grassland management plan for Wertheim National Wildlife Refuge is presented as an interim document to provide refuge staff in 1989 with management guidelines...

  18. New taxa of Entoloma from grasslands in Drenthe, The Netherlands

    NARCIS (Netherlands)

    Arnolds, E.J.M.; Noordeloos, M.E.

    1979-01-01

    Fourteen new species and three new variaties of Entoloma from grassland vegetations in the province of Drenthe, The Netherlands, are described: E. acidophilum, E. argenteostriatum, E. calthionis, E. chlorinosum, E. cryptocystidiatum, E. cuniculorum. E. defibulatum, E. farinogustus, E.

  19. Effects of Habitat Manipulation on Grassland Bird Populations

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Because of continuing concern over the decline of grassland bird populations in the Northeast, and the fact that many management activities designed to increase...

  20. Grassland bird survey protocol : Kulm Wetland Management District

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Initial Survey Instructions for the grassland bird survey at Kulm Wetland Management District. This survey occurs between May 15th and July 15th annually. All...

  1. Experimental study on soil respiration of temperate grassland in China

    Institute of Scientific and Technical Information of China (English)

    WANG Gengchen; DU Rui; KONG Qinxin; L(U) Daren

    2004-01-01

    Experimental study on soil respiration of typical temperate grassland in Inner Mongolia was conducted in the period of 1998-2000. Closed chamber and GC/FID techniques were used for measurements of soil and plant respiration. Data analysis of three-year measurements show that temperate grassland soil respiration varied in the range of 390-866 gC/m2·a-1 and underwent evident seasonal and annual variations. On average, the soil respiration accounts for 70%-88% of the grassland total respiration. Results also show a stronger relation between the soil respiration and soil temperature in water abundant years. Increased rainfall in 1998 made soil respiration increased, while in the dry years, the relation between soil respiration and soil temperature weakened remarkably. Soit water content plays an important controlling role in soil respiration-temperature interrelation for semiarid grassland.

  2. The effect of grassland management on enchytraeids (Oligochaeta) communities

    DEFF Research Database (Denmark)

    Maraldo, Kristine; Schmelz, Rüdiger; Christensen, Bent Tolstrup

    2012-01-01

    Enchytraeids (small white earthworms between 3 to 35 mm) are important regulators of nitrogen turnover in grasslands, as their activities accelerate the decomposition and nutrient recycling processes. In this study, the effect of management on species composition, abundance and biomass...

  3. Seasonal methane dynamics in three temperate grasslands on peat

    DEFF Research Database (Denmark)

    Schäfer, Carolyn; Elsgaard, Lars; Hoffmann, Carl Christian;

    2012-01-01

    Background and Aims Drained peatlands are considered to be insignificant CH4 sources, but the effect of drainage on CH4 dynamics has not been extensively studied. We investigated seasonal dynamics of CH4 in two fen peat soils and one bog peat soil under permanent grassland in Denmark. Methods Soil...... of aerenchymous plants should be considered before dismissing grasslands on peat as CH4 sources....

  4. Methods for evaluation of the invasibility of grasslands

    DEFF Research Database (Denmark)

    Strandberg, M. T.; Strandberg, B.; Erneberg, M.

    The number of non-native plant species in Danish dry acidic grasslands was positively correlated with the cover of disturbance in the form of molehills, anthills, mouseholes and erosion due trampling or digging by large herbivores/livestock. Natural disturbance in acidic grassland ecosystems...... not grazed by livestock therefore is important for the occurrence of non-native species, and probably also for the occurrence of a high native floristic diversity....

  5. Mental health outcomes at the Jersey Shore after Hurricane Sandy.

    Science.gov (United States)

    Boscarino, Joseph A; Hoffman, Stuart N; Kirchner, H Lester; Erlich, Porat M; Adams, Richard E; Figley, Charles R; Solhkhah, Ramon

    2013-01-01

    On October 29, 2012, Hurricane Sandy made landfall in the most densely populated region in the US. In New Jersey, thousands of families were made homeless and entire communities were destroyed in the worst disaster in the history of the state. The economic impact of Sandy was huge, comparable to Hurricane Katrina. The areas that sustained the most damage were the small- to medium-sized beach communities along New Jersey's Atlantic coastline. Six months following the hurricane, we conducted a random telephone survey of 200 adults residing in 18 beach communities located in Monmouth County. We found that 14.5% (95% CI = 9.9-20.2) of these residents screened positive for PTSD and 6.0% (95% CI = 3.1-10.2) met criteria for major depression. Altogether 13.5% (95% CI = 9.1-19.0) received mental health counseling and 20.5% (95% CI = 15.1-26.8) sought some type of mental health support in person or online, rates similar to those reported in New York after the World Trade Center disaster In multivariate analyses, the best predictors of mental health status and service use were having high hurricane exposure levels, having physical health limitations, and having environmental health concerns. Research is needed to assess the mental health status and service use of Jersey Shore residents over time, to evaluate environmental health concerns, and to better understand the storm's impact among those with physical health limitations.

  6. Trophic niche shifts driven by phytoplankton in sandy beach ecosystems

    Science.gov (United States)

    Bergamino, Leandro; Martínez, Ana; Han, Eunah; Lercari, Diego; Defeo, Omar

    2016-10-01

    Stable isotopes (δ13C and δ15N) together with chlorophyll a and densities of surf diatoms were used to analyze changes in trophic niches of species in two sandy beaches of Uruguay with contrasting morphodynamics (i.e. dissipative vs. reflective). Consumers and food sources were collected over four seasons, including sediment organic matter (SOM), suspended particulate organic matter (POM) and the surf zone diatom Asterionellopsis guyunusae. Circular statistics and a Bayesian isotope mixing model were used to quantify food web differences between beaches. Consumers changed their trophic niche between beaches in the same direction of the food web space towards higher reliance on surf diatoms in the dissipative beach. Mixing models indicated that A. guyunusae was the primary nutrition source for suspension feeders in the dissipative beach, explaining their change in dietary niche compared to the reflective beach where the proportional contribution of surf diatoms was low. The high C/N ratios in A. guyunusae indicated its high nutritional value and N content, and may help to explain the high assimilation by suspension feeders at the dissipative beach. Furthermore, density of A. guyunusae was higher in the dissipative than in the reflective beach, and cell density was positively correlated with chlorophyll a only in the dissipative beach. Therefore, surf diatoms are important drivers in the dynamics of sandy beach food webs, determining the trophic niche space and productivity. Our study provides valuable insights on shifting foraging behavior by beach fauna in response to changes in resource availability.

  7. [Soil particle size distribution and its fractal dimension among degradation sequences of the alpine meadow in the source region of the Yangtze and Yellow River, Qinghai-Tibetan Plateau, China].

    Science.gov (United States)

    Wei, Mao-Hong; Lin, Hui-Long

    2014-03-01

    The alpine meadow in the source region of the Yangtze and Yellow River is suffering serious deterioration. Though great efforts have been put into, the restoration for the degraded grassland is far from being effective, mainly due to poor understanding of the degradation mechanism of alpine meadow in this region. In order to clarify the formation mechanism of degradation grassland and provide the new ideas for restoration, degradation sequences of the alpine meadow in the source region of the Yangtze and Yellow River were taken as target systems to analyze the soil particle size distribution, the fractal dimension of the soil particle size, and the relationship between soil erosion modulus and fractal dimension. The results showed that, with increasing grassland degradation, the percentage contents of clay increased while the percentage contents of silt sand and very fine sand showed a decreasing trend. The fractal dimension presented a positive correlation with clay among the degradation sequences while negative correlations were found with very fine sand and silt sand. The curvilinear regression of fractal dimension and erosion modulus fitted a quadratic function. Judged by the function, fractal dimension 2.81 was the threshold value of soil erosion. The threshold value has an indicative meaning on predicting the breakout of grazing-induced erosion and on restoration of the degraded grassland. Taking fractal dimension of 2.81 as the restoration indicator, adoption of corresponding measures to make fractal dimension less than 2.81, would an effective way to restore the degradation grassland.

  8. A Coordinated USGS Science Response to Hurricane Sandy

    Science.gov (United States)

    Jones, S.; Buxton, H. T.; Andersen, M.; Dean, T.; Focazio, M. J.; Haines, J.; Hainly, R. A.

    2013-12-01

    In late October 2012, Hurricane Sandy came ashore during a spring high tide on the New Jersey coastline, delivering hurricane-force winds, storm tides exceeding 19 feet, driving rain, and plummeting temperatures. Hurricane Sandy resulted in 72 direct fatalities in the mid-Atlantic and northeastern United States, and widespread and substantial physical, environmental, ecological, social, and economic impacts estimated at near $50 billion. Before the landfall of Hurricane Sandy, the USGS provided forecasts of potential coastal change; collected oblique aerial photography of pre-storm coastal morphology; deployed storm-surge sensors, rapid-deployment streamgages, wave sensors, and barometric pressure sensors; conducted Light Detection and Ranging (lidar) aerial topographic surveys of coastal areas; and issued a landslide alert for landslide prone areas. During the storm, Tidal Telemetry Networks provided real-time water-level information along the coast. Long-term networks and rapid-deployment real-time streamgages and water-quality monitors tracked river levels and changes in water quality. Immediately after the storm, the USGS serviced real-time instrumentation, retrieved data from over 140 storm-surge sensors, and collected other essential environmental data, including more than 830 high-water marks mapping the extent and elevation of the storm surge. Post-storm lidar surveys documented storm impacts to coastal barriers informing response and recovery and providing a new baseline to assess vulnerability of the reconfigured coast. The USGS Hazard Data Distribution System served storm-related information from many agencies on the Internet on a daily basis. Immediately following Hurricane Sandy the USGS developed a science plan, 'Meeting the Science Needs of the Nation in the Wake of Hurricane Sandy-A U.S. Geological Survey Science Plan for Support of Restoration and Recovery'. The plan will ensure continuing coordination of internal USGS activities as well as

  9. Microbial sewage contamination associated with Superstorm Sandy flooding in New York City

    Science.gov (United States)

    O'Mullan, G.; Dueker, M.; Sahajpal, R.; Juhl, A. R.

    2013-05-01

    The lower Hudson River Estuary commonly experiences degraded water quality following precipitation events due to the influence of combined sewer overflows. During Super-storm Sandy large scale flooding occurred in many waterfront areas of New York City, including neighborhoods bordering the Gowanus Canal and Newtown Creek Superfund sites known to frequently contain high levels of sewage associated bacteria. Water, sediment, and surface swab samples were collected from Newtown Creek and Gowanus Canal flood impacted streets and basements in the days following the storm, along with samples from the local waterways. Samples were enumerated for the sewage indicating bacterium, Enterococcus, and DNA was extracted and amplified for 16S ribosomal rRNA gene sequence analysis. Waterways were found to have relatively low levels of sewage contamination in the days following the storm. In contrast, much higher levels of Enterococci were detected in basement and storm debris samples and these bacteria were found to persist for many weeks in laboratory incubations. These data suggest that substantial sewage contamination occurred in some flood impacted New York City neighborhoods and that the environmental persistence of flood water associated microbes requires additional study and management attention.

  10. Toward sustainable desertification reversion:A case study in Horqin Sandy Land of northern China

    Institute of Scientific and Technical Information of China (English)

    XueYong Zhao; ShaoKun Wang; YaYong Luo; WenDa Huang; Hao Qu; Jie Lian

    2015-01-01

    Desertification reversion is an interactive process involving climate, land use change, and water processes. In order to reveal the relationship between desertification reversion and these factors, we analyzed historical data on precipitation, air temperature, desertified land changes, underground water tables, and water body changes in Naiman County in the central part of Horqin Sandy Land. Our analysis showed that during 1961−2010 the annual precipitation fluctuated dramatically and has decreased fairly consistently in recent years. The air temperature increased by 0.50−1.25 °C, and the minimum temperature increased more obviously. The desertified land area increased from 42,300 km2 in 1959 to 62,000 km2 in 1985, and then declined to about 50,000 km2 in 2010. The underground water tables have been lowered by about 10 m in the past 30 years, and declined more rapidly in recent years. Desertified land is significantly related to the amount of total cropland, and underground water tables are significantly correlated with annual precipitation and the amount of irrigated cropland. Therefore, it is necessary to pursue sustainable desertification reversion without compromising the capacity for local de-velopment and restoration of degraded land, through application of appropriate management measures for improving water availability in this region.

  11. Phytotoxicity and uptake of nitroglycerin in a natural sandy loam soil.

    Science.gov (United States)

    Rocheleau, Sylvie; Kuperman, Roman G; Dodard, Sabine G; Sarrazin, Manon; Savard, Kathleen; Paquet, Louise; Hawari, Jalal; Checkai, Ronald T; Thiboutot, Sonia; Ampleman, Guy; Sunahara, Geoffrey I

    2011-11-15

    Nitroglycerin (NG) is widely used for the production of explosives and solid propellants, and is a soil contaminant of concern at some military training ranges. NG phytotoxicity data reported in the literature cannot be applied directly to development of ecotoxicological benchmarks for plant exposures in soil because they were determined in studies using hydroponic media, cell cultures, and transgenic plants. Toxicities of NG in the present studies were evaluated for alfalfa (Medicago sativa), barnyard grass (Echinochloa crusgalli), and ryegrass (Lolium perenne) exposed to NG in Sassafras sandy loam soil. Uptake and degradation of NG were also evaluated in ryegrass. The median effective concentration values for shoot growth ranged from 40 to 231 mg kg(-1) in studies with NG freshly amended in soil, and from 23 to 185 mg kg(-1) in studies with NG weathered-and-aged in soil. Weathering-and-aging NG in soil did not significantly affect the toxicity based on 95% confidence intervals for either seedling emergence or plant growth endpoints. Uptake studies revealed that NG was not accumulated in ryegrass but was transformed into dinitroglycerin in the soil and roots, and was subsequently translocated into the ryegrass shoots. The highest bioconcentration factors for dinitroglycerin of 685 and 40 were determined for roots and shoots, respectively. Results of these studies will improve our understanding of toxicity and bioconcentration of NG in terrestrial plants and will contribute to ecological risk assessment of NG-contaminated sites.

  12. Simulating transport and removal of xylene during remediation of a sandy aquifer

    Science.gov (United States)

    Schäfer, Wolfgang; Therrien, René

    1995-09-01

    Xylene, originating from a spill, is present both as a nonaqueous-phase liquid (NAPL) at residual saturation near the water table, and as a dissolved groundwater component contaminating a sandy aquifer beneath an abandoned refinery. Three remediation wells are in operation on the site to prevent further xylene migration in the groundwater. Field observations indicate that microbially-mediated xylene degradation and oxygen and nitrate reduction occur in the aquifer. To realistically simulate dissolved xylene migration at this site, a three-dimensional numerical flow and transport model incorporating biochemical multispecies interactions and xylene dissolution from the NAPL has been developed. In the calibration process the variable contact area between the NAPL and groundwater and the vertical transverse dispersivity were identified as crucial parameters controlling the fate of xylene. The simultaneous modeling of a whole set of related reactive species made it also possible to quantify the observed biodegradation. Results indicate that it contributes in the same order of magnitude to total xylene removal than does extraction by the wells. The calibrated model will be used to assist in the design of an in situ bioremediation scheme, where biodegradation in the aquifer is enhanced by injection of an electron acceptor.

  13. LUCC and Accompanied Soil Degradation in China from 1960's to 1990's

    Institute of Scientific and Technical Information of China (English)

    JIANG Qigang; Shintaro GOTO; Hiroki TAKAMURA

    2002-01-01

    This paper tries to qualitatively analyze land use and cover changes (LUCC) and accompanied soil degradation in China, the data of World Atlas of Agriculture in 1969, Land Cover Data of Asia in 1992 and Global Assessment of Human Induced Soil Degradation in 1992, etc. have been used. From 1960' s to 1990's, the area of forestland had increased, arable land and paddy as well as grassland had significantly decreased in China. The major type of soil degradation is due to water erosion, which is widely distributed especially in Loess Plateau and in Southeast and Southwest China, this happened in forestland, grassland and arable land and mainly resulted from deforestation. The secondary type is wind erosion, which is mainly distributed in Northwest China, it happened in arable land and grassland and was caused by overgrazing. Chemical deterioration is distributed in North and Northwest China, which happened in paddy, arable land and grassland. Physical deterioration only concentrated in local area in North China, it happened in arable and paddy. Chemical and physical deteriora-tion mainly resulted from unreasonable activity. Because of different human activities, different LUCC and different natural conditions, the types and strength of soil degradation can be different.

  14. Habitat and landscape effects on abundance of Missouri's grassland birds

    Science.gov (United States)

    Jacobson, Robert B.; Thompson, Frank R.; Koford, Rolf R.; La Sorte, Frank A.; Woodward, Hope D.; Fitzgerald, Jane A.

    2012-01-01

    Of 6 million ha of prairie that once covered northern and western Missouri, radius). We found support for all 3 levels of model parameters, although there was less support for landscape than vegetation structure effects likely because we studied high-percentage-grassland landscapes (BCAs). Henslow's sparrow (Ammodramus henslowii) counts increased with greater percentage of grassland, vegetation height-density, litter depth, and shrub cover and lower edge density. Henslow's sparrow counts were greatest in hayed native prairie. Dickcissel (Spiza americana) counts increased with greater vegetation height-density and were greatest in planted CRP grasslands. Grasshopper sparrow (A. savannarum) counts increased with lower vegetation height, litter depth, and shrub cover. Based on distance modeling, breeding densities of Henslow's sparrow, dickcissel, and grasshopper sparrow in the 6 grassland types ranged 0.9–2.6, 1.4–3.2, and 0.1–1.5 birds/ha, respectively. We suggest different grassland types and structures (vegetation height, litter depth, shrub cover) are needed to support priority grassland-bird species in Missouri.

  15. Soil Organic Carbon Responses to Forest Expansion on Mountain Grasslands

    DEFF Research Database (Denmark)

    Guidi, Claudia

    Grassland abandonment followed by progressive forest expansion is the dominant land-use change in the European Alps. Contrasting trends in soil organic carbon (SOC) stocks have been reported for mountainous regions following forest expansion on grasslands. Moreover, its effects on SOC properties ...... grasslands, which can be explained by lower accumulation of binding agents of microbial origin. This can have implications for the accumulation of atmospheric CO2 in soil and for the susceptibility of SOC to external disturbances such as management and environmental changes.......Grassland abandonment followed by progressive forest expansion is the dominant land-use change in the European Alps. Contrasting trends in soil organic carbon (SOC) stocks have been reported for mountainous regions following forest expansion on grasslands. Moreover, its effects on SOC properties...... involved into long-term stability are largely unknown. The aim of this PhD thesis was to explore changes in: (i) SOC stocks; (ii) physical SOC fractions; and (iii) labile soil carbon components following forest expansion on mountain grasslands. A land-use gradient located in the Southern Alps (Italy...

  16. Study on Soil and Water Conservation Benefit Models of Grassland Ecosystem-A Case Study on Jianou Mountain Grassland Ecosystem

    Institute of Scientific and Technical Information of China (English)

    ZHU Lian-qi; WANG Yu-biao; ZHAO Qing-liang

    2001-01-01

    This paper studies the mechanism of grassland ecosystem's soil and water conservation function on the basis of two years experiment and inspection in Jianou mountain grassland ecosystem experiment station, Fujian province. After analysis on the data of soil erosion and runoff coefficient, relations between eroded soil. runoff and slope gradient, we establish soil and water conservation benefit models. According to the models, experiment and inspection results, some proposals have been made to decrease the area of soil erosion in Fujian mountainous areas, e. g. , optimizing land use structure in mountainous areas, taking suitable measures for local condition, closing hills for grassland development, accelerating restoration and raising quality of mountain grassland ecosystem, strengthening scientific and technological input, breeding the grass species that are suitable to local physical geographic condition.

  17. Grassland breeding bird use of managed grasslands on National Wildlife Refuges in Region 5 of the Fish and Wildlife Service

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The overall purpose of this project is to understand the likely capacity of Fish and Wildlife Service land managers to affect grassland bird populations in Region 5....

  18. Soil water retention, air flow and pore structure characteristics after corn cob biochar application to a tropical sandy loam

    DEFF Research Database (Denmark)

    Amoakwah, Emmanuel; Frimpong, Kwame Agyei; Okae-Anti, D

    2017-01-01

    Soil structure is a key soil physical property that affects soil water balance, gas transport, plant growth and development, and ultimately plant yield. Biochar has received global recognition as a soil amendment with the potential to ameliorate the structure of degraded soils. We investigated how...... corn cob biochar contributed to changes in soil water retention, air flow by convection and diffusion, and derived soil structure indices in a tropical sandy loam. Intact soil cores were taken from a field experiment that had plots without biochar (CT), and plots each with 10 t ha− 1 (BC-10), 20 t ha...... to significant increase in soil water retention compared to the CT and BC-10 as a result of increased microporosity (pores biochar had minimal impact. No significant influence of biochar was observed for ka and Dp/D0 for the BC treatments compared to the CT despite...

  19. Contribution of root to soil respiration and carbon balance in disturbed and undisturbed grassland communities, northeast China

    Indian Academy of Sciences (India)

    Wei Wang; Jixun Guo; Takehisa Oikawa

    2007-03-01

    Changes in the composition of plant species induced by grassland degradation may alter soil respiration rates and decrease carbon sequestration; however, few studies in this area have been conducted. We used net primary productivity (NPP), microbial biomass carbon (MBC), and soil organic carbon (SOC) to examine the changes in soil respiration and carbon balance in two Chinese temperate grassland communities dominated by Leymus chinensis (undisturbed community; Community 1) and Puccinellia tenuiflora (degraded community; Community 2), respectively. Soil respiration varied from 2.5 to 11.9 g CO2 m-2 d-1 and from 1.5 to 9.3 g CO2 m-2 d-1, and the contribution of root respiration to total soil respiration from 38% to 76% and from 25% to 72% in Communities 1 and 2, respectively. During the growing season (May–September), soil respiration, shoot biomass, live root biomass, MBC and SOC in Community 2 decreased by 28%, 39%, 45%, 55% and 29%, respectively, compared to those in Community 1. The considerably lower net ecosystem productivity in Community 2 than in Community 1 (104.56 vs. 224.73 g C m-2 yr-1) suggests that the degradation has significantly decreased carbon sequestration of the ecosystems.

  20. Coastal topography–Northeast Atlantic coast, post-hurricane Sandy, 2012

    Science.gov (United States)

    Stockdon, Hilary F.; Doran, Kara S.; Sopkin, Kristin L.; Smith, Kathryn E.L.; Fredericks, Xan

    2013-01-01

    This Data Series contains lidar-derived bare-earth (BE) topography, dune elevations, and mean-high-water shoreline position datasets for most sandy beaches for Fire Island, New York, and from Cape Henlopen, Delaware to Cape Lookout, North Carolina. The data were acquired post-Hurricane Sandy, which made landfall as an extratropical cyclone on October 29, 2012.

  1. Abrasive wear based predictive maintenance for systems operating in sandy conditions

    NARCIS (Netherlands)

    Woldman, M.; Tinga, T.; Heide, E. van der; Masen, M.A.

    2015-01-01

    Machines operating in sandy environments are damaged by the abrasive action of sand particles that enter the machine and become entrapped between components and contacting surfaces. In the case of the military services the combination of a sandy environment and the wide range of tasks to be fulfille

  2. Heterogeneous water flow and pesticide transport in cultivated sandy soils : description of model concepts

    NARCIS (Netherlands)

    Leistra, M.; Boesten, J.J.T.I.

    2011-01-01

    There is ample experimental evidence that complications in water flow and pesticide transport can occur in cultivated humic-sandy and loamy-sandy soils. As a result, pesticide leaching to groundwater and water courses can be higher than expected. We made an inventory of mechanistic/deterministic mod

  3. Measuring Sandy Bottom Dynamics by Exploiting Depth from Stereo Video Sequences

    DEFF Research Database (Denmark)

    Musumeci, Rosaria E.; Farinella, Giovanni M.; Foti, Enrico;

    2013-01-01

    In this paper an imaging system for measuring sandy bottom dynamics is proposed. The system exploits stereo sequences and projected laser beams to build the 3D shape of the sandy bottom during time. The reconstruction is used by experts of the field to perform accurate measurements and analysis i...

  4. Marine meiofauna, carbon and nitrogen mineralization in sandy and soft sediments of Disko Bay, West Greenland

    DEFF Research Database (Denmark)

    Rysgaard, S.; Christensen, P.B.; Sørensen, Martin Vinther

    2000-01-01

    belonging to Platyhelminthes, Rotifera, Gastrotricha, and Protodriloidae (Polychaeta) occurred only at the sandy locality, whereas Kinorhyncha, Foraminifera, and Cumacea (Crustacea) occurred only at the muddy stations. The larger number of meiofauna individuals at the sandy locality may in part be explained...

  5. Fine-scale spatial distribution of plants and resources on a sandy soil in the Sahel

    NARCIS (Netherlands)

    Rietkerk, M; Ouedraogo, T; Kumar, L; Sanou, S; van Langevelde, F; Kiema, A; van de Koppel, J; van Andel, J; Hearne, J; Skidmore, AK; de Ridder, N; Stroosnijder, L; Prins, HHT

    We studied fine-scale spatial plant distribution in relation to the spatial distribution of erodible soil particles, organic matter, nutrients and soil water on a sandy to sandy loam soil in the Sahel. We hypothesized that the distribution of annual plants would be highly spatially autocorrelated

  6. Fine-scale spatial distribution of plants and resources on a sandy soil in the Sahel

    NARCIS (Netherlands)

    Rietkerk, M.G.; Ouedraogo, T.; Kumar, L.; Sanou, S.; Langevelde, F. van; Kiema, A.; Koppel, J. van de; Andel, J. van; Hearne, J.; Skidmore, A.K.; Ridder, N. de; Stroosnijder, L.; Prins, H.H.T.

    2002-01-01

    We studied fine-scale spatial plant distribution in relation to the spatial distribution of erodible soil particles, organic matter, nutrients and soil water on a sandy to sandy loam soil in the Sahel. We hypothesized that the distribution of annual plants would be highly spatially autocorrelated

  7. Nitrate leaching to groundwater at experimental farm "De Marke" and other Dutch sandy soils

    NARCIS (Netherlands)

    Hack-ten Broeke, M.J.D.

    2001-01-01

    This study focuses on nitrate leaching to the groundwater as a result of the land use system of experimental farm 'De Marke', translated to other sandy soils in the Netherlands. The land use was extrapolated to five major sandy soil map units, selected from the 1: 50 000 Soil Map of the Netherlands,

  8. 33 CFR 80.170 - Sandy Hook, NJ to Tom's River, NJ.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Sandy Hook, NJ to Tom's River, NJ. 80.170 Section 80.170 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Atlantic Coast § 80.170 Sandy Hook, NJ to Tom's River...

  9. Twelve years of succession on sandy substrates in a post-mining landscape: a Markov chain analysis.

    Science.gov (United States)

    Baasch, Annett; Tischew, Sabine; Bruelheide, Helge

    2010-06-01

    Knowledge of succession rates and pathways is crucial for devising restoration strategies for highly disturbed ecosystems such as surface-mined land. As these processes have often only been described in qualitative terms, we used Markov models to quantify transitions between successional stages. However, Markov models are often considered not attractive for some reasons, such as model assumptions (e.g., stationarity in space and time, or the high expenditure of time required to estimate successional transitions in the field). Here we present a solution for converting multivariate ecological time series into transition matrices and demonstrate the applicability of this approach for a data set that resulted from monitoring the succession of sandy dry grassland in a post-mining landscape. We analyzed five transition matrices, four one-step matrices referring to specific periods of transition (1995-1998, 1998-2001, 2001-2004, 2004-2007), and one matrix for the whole study period (stationary model, 1995-2007). Finally, the stationary model was enhanced to a partly time-variable model. Applying the stationary and the time-variable models, we started a prediction well outside our calibration period, beginning with 100% bare soil in 1974 as the known start of the succession, and generated the coverage of 12 predefined vegetation types in three-year intervals. Transitions among vegetation types changed significantly in space and over time. While the probability of colonization was almost constant over time, the replacement rate tended to increase, indicating that the speed of succession accelerated with time or fluctuations became stronger. The predictions of both models agreed surprisingly well with the vegetation data observed more than two decades later. This shows that our dry grassland succession in a post-mining landscape can be adequately described by comparably simple types of Markov models, although some model assumptions have not been fulfilled and within

  10. Effects of vegetable oil residue after soil extraction on physical-chemical properties of sandy soil and plant growth.

    Science.gov (United States)

    Gong, Zongqiang; Li, Peijun; Wilke, B M; Alef, Kassem

    2008-01-01

    Vegetable oil has the ability to extract polycyclic aromatic hydrocarbons (PAHs) from contaminated sandy soil for a remediation purpose, with some of the oil remaining in the soil. Although most of the PAHs were removed, the risk of residue oil in the soil was not known. The objective of this study was to evaluate the effects of the vegetable oil residue on higher plant growth and sandy soil properties after soil extraction for a better understanding of the soil remediation. Addition of sunflower oil and column experiment were performed on a PAH contaminated soil and/or a control soil, respectively. Soils were incubated for 90 d, and soil pH was measured during the soil incubation. Higher plant growth bioassays with Avena sativa L. (oat) and Brassica rapa L. (turnip) were performed after the incubation, and then soil organic carbon contents were measured. The results show that both the nutrient amendment and the sunflower oil degradation resulted in the decrease of soil pH. When these two process worked together, their effects were counteracted due to the consumption of the nutrients and oil removal, resulting in different pH profiles. Growth of A. sativa was adversely affected by the sunflower oil, and the nutrient amendments stimulated the A. sativa growth significantly. B. rapa was more sensitive to the sunflower oil than A. sativa. Only 1% sunflower oil addition plus nutrient amendment stimulated B. rapa growth. All the other treatments on B. rapa inhibited its growth significantly. The degradation of the sunflower oil in the soils was proved by the soil organic carbon content.

  11. Effects of vegetable oil residue after soil extraction on physical-chemical properties of sandy soil and plant growth

    Institute of Scientific and Technical Information of China (English)

    GONG Zongqiang; LI Peijun; B.M.Wilke; Kassem Alef

    2008-01-01

    Vegetable oil has the ability to extract polycyclic aromatic hydrocarbons (PAHs) from contaminated sandy soft for a remediation purpose, with some of the oft remaining in the soil. Although most of the PAHs were removed, the risk of residue oil in the soft was not known. The objective of this study was to evaluate the effects of the vegetable oil residue on higher plant growth and sandy soft properties after soil extraction for a better understanding of the soil remediation. Addition of sunflower oil and column experiment were performed on a PAH contaminated soil and/or a control soft, respectively. Soils were incubated for 90 d, and soil pH was measured during the soil incubation. Higher plant growth bioassays with Avena sativa L. (oat) and Brassica rapa L. (turnip) were performed after the incubation, and then soil organic carbon contents were measured. The results show that both the nutrient amendment and the sunflower oil degradation resulted in the decrease of soil pH. When these two process worked together, their effects were counteracted due to the consumption of the nutrients and oil removal, resulting in different pH profiles. Growth ofA. sativa was adversely affected by the sunflower oil, and the nutrient amendments stimulated the A. sativa growth significantly. B. rapa was more sensitive to the sunflower oil than A. sativa. Only 1% sunflower oft addition plus nutrient amendment stimulated B. rapa growth. All the other treatments on B. rapa inhibited its growth significantly. The degradation of the sunflower oft in the soils was proved by the soft organic carbon content.

  12. Effects of shallow natural gas well structures and associated roads on grassland songbird reproductive success in Alberta, Canada.

    Science.gov (United States)

    Yoo, Jenny; Koper, Nicola

    2017-01-01

    Grassland songbird populations across North America have experienced dramatic population declines due to habitat loss and degradation. In Canada, energy development continues to fragment and disturb prairie habitat, but effects of oil and gas development on reproductive success of songbirds in North American mixed-grass prairies remains largely unknown. From 2010-2012, in southeastern Alberta, Canada, we monitored 257 nests of two ground-nesting grassland songbird species, Savannah sparrow (Passerculus sandwichensis) and chestnut-collared longspur (Calcarius ornatus). Nest locations varied with proximity to and density of conventional shallow gas well structures and associated roads in forty-two 258-ha mixed-grass prairie sites. We estimated the probabilities of nest success and clutch size relative to gas well structures and roads. There was little effect of distance to or density of gas well structure on nest success; however, Savannah sparrow experienced lower nest success near roads. Clutch sizes were lower near gas well structures and cattle water sources. Minimizing habitat disturbance surrounding gas well structures, and reducing abundance of roads and trails, would help minimize impacts on reproductive success for some grassland songbirds.

  13. The fate of fresh and stored 15N-labelled sheep urine and urea applied to a sandy and a sandy loam soil using different application strategies

    DEFF Research Database (Denmark)

    Sørensen, P.; Jensen, E.S.

    1996-01-01

    .), or it was applied to ryegrass one month after sowing. In a sandy loam soil, 62% of the incorporated urine N and 78% of the incorporated urea N was recovered in three cuts of herbage after 5 months. In a sandy soil, 51-53% of the labelled N was recovered in the herbage and the distribution of labelled N in plant...... and soil was not significantly different for incorporated urine and urea. Almost all the supplied labelled N was accounted for in soil and herbage in the sandy loam soil, whereas 33-34% of the labelled N was unaccounted for in the sandy soil. When the stored urine was applied to the soil surface, 20...... unaccounted for was probably mainly lost by ammonia volatilization. Significantly more urine- than urea-derived N (36 and 19%, respectively) was immobilized in the sandy loam soil, whereas the immobilization of N from urea and urine was similar in the sandy soil (13-16%). The distribution of urine N, whether...

  14. Seasonal variation of bivalve larvae on an exposed sandy beach on Kashima-nada: Tips for the sandy beach recruitment process

    Science.gov (United States)

    Sawada, Hideki; Saito, Hajime; Adachi, Kumiko; Toyohara, Haruhiko

    2011-02-01

    Bivalves are often the dominant macrobenthos species in exposed sandy beach environments. However, our understanding of their recruitment processes before post-settlement stages on sandy beaches with highly energetic environments is incomplete. To clarify the characteristics of the free-swimming planktonic stage that affects recruitment efficiency in sandy shore ecosystems, we investigated the temporal (weekly-biweekly) variation of bivalve planktonic larval concentration coupled with oceanographic conditions on an exposed sandy shore on the sea of Kashima-nada, Japan, from summer 2003 to autumn 2005. Larvae were observed throughout the year, but the surge of larval concentration composed of sandy beach and sessile bivalves occurred most prominently in summer, from August to September. The peak concentration of larvae during this season was more than 1000 times higher than in other seasons. The larval concentration was positively correlated with water temperature and northward wind velocity and negatively correlated with each of the nutrient concentrations. On the other hand, chlorophyll a concentration and salinity seemed to have little effect on the larval concentration. Based on this fundamental knowledge, further investigations about planktonic larvae in sandy beaches are needed.

  15. Mechanisms of humic substances degradation by fungi

    Science.gov (United States)

    Chen, Y.; Hadar, Y.; Grinhut, T.

    2012-04-01

    Humic substances (HS) are formed by secondary synthesis reactions (humification) during the decay process and transformation of biomolecules originating from plants and other dead organisms. In nature, HS are extremely resistant to biological degradation. Thus, these substances are major components in the C cycle and in the biosphere and therefore, the understanding of the process leading to their formation and transformation and degradation is vital. Fungi active in the decomposition process of HS include mainly ascomycetes and basidiomycetes that are common in the upper layer of forest and grassland soils. Many basidiomycetes belong to the white-rot fungi (WRF) and litter-decomposing fungi (LDF). These fungi are considered to be the most efficient lignin degraders due to their nonspecific oxidizing enzymes: manganese peroxidase (MnP), lignin peroxidase (LiP) and laccase. Although bacteria dominate compost and participate in the turnover of HS, their ability to degrade stable macromolecules such as lignin and HS is limited. The overall objectives of this research were to corroborate biodegradation processes of HS by WRF. The specific objectives were: (i) To isolate, identify and characterize HS degrading WRF from biosolids (BS) compost; (ii) To study the biodegradation process of three types of HS, which differ in their structure, by WRF isolated from BS compost; and (iii) To investigate the mechanisms of HA degradation by WRF using two main approaches: (a) Study the physical and chemical analyses of the organic compounds obtained from direct fungal degradation of HA as well as elucidation of the relevant enzymatic reactions; and (b) Study the enzymatic and biochemical mechanisms involved during HA degradation. In order to study the capability of fungi to degrade HS, seventy fungal strains were isolated from biosolids (BS) compost. Two of the most active fungal species were identified based on rDNA sequences and designated Trametes sp. M23 and Phanerochaetesp., Y6

  16. Evidence for linkages between ecoenzyme activity and soil organic matter chemistry following encroachment of leguminous woody plant into grasslands.

    Science.gov (United States)

    Filley, Timothy; Stott, Diane; Boutton, Thomas; Creamer, Courtney; Olk, Dan

    2010-05-01

    The encroachment of woody plants into grasslands is a worldwide phenomenon. In the Rio Grande Plains of southern Texas, subtropical thorn woodlands dominated by the N-fixing tree Prosopis glandulosa have largely replaced native grasslands as a result of fire suppression and extensive cattle grazing. This land cover change has resulted in the increase of belowground stocks of C, N, and P, changes to the amount and chemical nature of soil-stabilized plant biopolymers, and the composition and activity of soil microbes. Given that extracellular enzymes produced by plants and microbes are the principal means by which complex compounds are degraded and that the production of such enzymes is triggered or suppressed by changes in substrate and nutrient availability we sought to relate how these fundamental changes in this ecosystem are reflected in the activity of soil stabilized ecoenzymes and soil organic matter (SOM) chemistry in this system. We investigated a chronosequence of woody encroachment (14-86 yrs) into a C4-dominant grassland. We related the potential activities of five extracellular enzymes (arylamidase, acid phosphatase, β-glucosidase, β-glucosaminidase (NAGase, polyphenoloxidase (PPO)) and a general marker for hydrolytic activity, fluorescein diacetate (FDA) to the molecular composition and concentration of total hydrolysable amino acids and amino sugars, sugars, as well as CuO extractable lignin and substituted fatty acid to. When normalized to dry weight soil all chemical components increase in concentration with cluster age and all clusters have greater concentrations than background grasslands. All enzymes activities exhibit higher potential activity in woody clusters than grasslands but only NAGase and FDA increase with cluster age when normalized to dry weight of soil. Conversely, when normalized to SOC only lignin phenols, hydroxyl proline, and glucose from cellulose are positively correlated with cluster age indicating a selective accrual with

  17. Response of grassland ecosystems to prolonged soil moisture deficit

    Science.gov (United States)

    Ross, Morgan A.; Ponce-Campos, Guillermo E.; Barnes, Mallory L.; Hottenstein, John D.; Moran, M. Susan

    2014-05-01

    Soil moisture is commonly used for predictions of plant response and productivity. Climate change is predicted to cause an increase in the frequency and duration of droughts over the next century, which will result in prolonged periods of below-normal soil moisture. This, in turn, is expected to impact regional plant production, erosion and air quality. In fact, the number of consecutive months of soil moisture content below the drought-period mean has recently been linked to regional tree and shrub mortality in the southwest United States. This study investigated the effects of extended periods of below average soil moisture on the response of grassland ANPP to precipitation. Grassland ecosystems were selected for this study because of their ecological sensitivity to precipitation patterns. It has been postulated that the quick ecological response of grasslands to droughts can provide insight to large scale functional responses of regions to predicted climate change. The study sites included 21 grassland biomes throughout arid-to-humid climates in the United States with continuous surface soil moisture records for 2-13 years during the drought period from 2000-2013. Annual net primary production (ANPP) was estimated from the 13-year record of NASA MODIS Enhanced Vegetation Index extracted for each site. Prolonged soil moisture deficit was defined as a period of at least 10 consecutive months during which soil moisture was below the drought-period mean. ANPP was monitored before, during and after prolonged soil moisture deficit to quantify shifts in the functional response of grasslands to precipitation, and in some cases, new species assemblages that included invasive species. Preliminary results indicated that when altered climatic conditions on grasslands led to an increase in the duration of soil water deficit, then the precipitation-to-ANPP relation became non-linear. Non-linearity was associated with extreme grassland dieback and changes in the historic

  18. Coastal Topography--Northeast Atlantic Coast, Post-Hurricane Sandy, 2012: Lidar point-cloud data (LAS)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Binary point-cloud data were produced for a portion of the New York, Delaware, Maryland, Virginia, and North Carolina coastlines, post-Hurricane Sandy (Sandy was an...

  19. Coastal Topography--Northeast Atlantic Coast, Post-Hurricane Sandy, 2012: Lidar point-cloud data (LAS)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Binary point-cloud data were produced for a portion of the New York, Delaware, Maryland, Virginia, and North Carolina coastlines, post-Hurricane Sandy (Sandy was an...

  20. Experimental sand burial affects seedling survivorship, morphological traits, and biomass allocation of Ulmus pumila var. sabulosa in the Horqin Sandy Land, China

    Science.gov (United States)

    Tang, Jiao; Busso, Carlos Alberto; Jiang, Deming; Musa, Ala; Wu, Dafu; Wang, Yongcui; Miao, Chunping

    2016-07-01

    As a native tree species, Ulmus pumila var. sabulosa (sandy elm) is widely distributed in the Horqin Sandy Land, China. However, seedlings of this species have to withstand various depths of sand burial after emergence because of increasing soil degradation, which is mainly caused by overgrazing, climate change, and wind erosion. An experiment was conducted to evaluate the changes in its survivorship, morphological traits, and biomass allocation when seedlings were buried at different burial depths: unburied controls and seedlings buried vertically up to 33, 67, 100, or 133 % of their initial mean seedling height. The results showed that partial sand burial treatments (i.e., less than 67 % burial) did not reduce seedling survivorship, which still reached 100 %. However, seedling mortality increased when sand burial was equal to or greater than 100 %. In comparison with the control treatment, seedling height and stem diameter increased at least by 6 and 14 % with partial burial, respectively. In the meantime, seedling taproot length, total biomass, and relative mass growth rates were at least enhanced by 10, 15.6, and 27.6 %, respectively, with the partial sand burial treatment. Furthermore, sand burial decreased total leaf area and changed biomass allocation in seedlings, partitioning more biomass to aboveground organs (e.g., leaves) and less to belowground parts (roots). Complete sand burial after seedling emergence inhibited its re-emergence and growth, even leading to death. Our findings indicated that seedlings of sandy elm showed some resistance to partial sand burial and were adapted to sandy environments from an evolutionary perspective. The negative effect of excessive sand burial after seedling emergence might help in understanding failures in recruitments of sparse elm in the study region.

  1. Scale Issues in Ecohydrological Processes in Grassland-Shrubland Transitions, Jornada, NM

    Science.gov (United States)

    Wainwright, J.; Parsons, A. J.; Mueller, E. N.; Schlesinger, W. H.

    2003-12-01

    Rainfall-simulation experiments have proved invaluable in developing our understanding of ecohydrological processes relating to grassland-shrubland transitions in the American Southwest and elsewhere. Grassland communities are effective at buffering the runoff and erosional response, whereas shrublands accelerate runoff and erosion rates leading to local concentrations of resources. Further feedbacks occur in terms of nutrient redistribution both dissolved in overland flow and adsorbed onto transported sediment. Field experiments at the Jornada LTER site over the last ten years have evaluated these processes on undisturbed and grazed black grama grassland, and creosotebush and mesquite shrubland communities. More recently, investigations have been carried out to evaluate the behaviour of these systems at the landscape scale. Low-cost sampling designs have been used so that relatively large spatial samples can be collected. Currently, 96 of these samplers are in operation at Jornada, evaluating water, sediment and nutrient transfers in the interrill zone. A smaller number of samplers are used to characterize rill transfers of water and dissolved nutrients. The samplers are located along ecotones so that the spatial relationship of grassland-shrubland and shrubland-shrubland transitions can be evaluated. An interesting initial result of the use of these samplers is that they provide different relative patterns of fluxes from those that would be estimated using the plot-based studies. These results contribute to the growing body of evidence that the scaling properties of landscape-degradation processes in these environments are non-linear. Further instrumentation of watersheds is being carried out in order to evaluate these non-linearities at larger scales. At the same time, intensive spatial sampling of hydrological, sedimentary and nutrient characteristics of the surfaces of the different vegetation communities is being carried out. The rationale for this sampling

  2. Assessment of grass root effects on soil piping in sandy soils using the pinhole test

    Science.gov (United States)

    Bernatek-Jakiel, Anita; Vannoppen, Wouter; Poesen, Jean

    2017-04-01

    Soil piping is a complex land degradation process, which involves the hydraulic removal of soil particles by subsurface flow. This process is frequently underestimated and omitted in most soil erosion studies. However, during the last decades several studies reported the importance of soil piping in various climatic zones and for a wide range of soil types. Compared to sheet, rill and gully erosion, very few studies focused on the factors controlling piping and, so far, there is no research study dealing with the effects of plant roots on piping susceptibility of soils having a low cohesion. The objective of this study is therefore to assess the impact of grass root density (RD) on soil piping in sandy soils using the pinhole test. The pinhole test involves a water flow passing through a hole of 1 mm diameter in a soil specimen (sampled using a metal ring with a diameter of 5 cm and a length of 8 cm), under varying hydraulic heads (50 mm, 180 mm, 380 mm and 1020 mm; Nadal-Romero et al., 2011). To provide a quantitative assessment piping susceptibility of the soil sample, the pipeflow discharge (cm3 s-1) and the sediment discharge (g s-1) were measured every minute during a five minute test. Bare and root-permeated samples were tested, using a sandy soil with a sand, silt, clay content of respectively, 94%, 4% and 2%. The root-permeated topsoil samples were taken in field plots sown with a mixture of grasses with fibrous roots. All soil samples were placed on a sandbox with a 100 mm head for 24 hours to ensure a similar water content for all samples. In total, 67 pinhole tests (lasting 5 minutes each) were conducted, i.e. 43 root-permeated soil samples with RD ranging from 0.01 to 0.93 kg m-3 and 24 root-free soil samples as a reference. Clear piping erosion could be observed in 65% of the root-free soil samples, whereas only 17% of rooted soil samples revealed clear piping erosion during the tests. Statistical analyses show that there is a negative correlation (-0

  3. Soil CO2 efflux in a sand grassland: contribution by root, mycorrhizal and basal respiration components

    Science.gov (United States)

    Papp, Marianna; Balogh, János; Pintér, Krisztina; Cserhalmi, Dóra; Nagy, Zoltán

    2014-05-01

    Grasslands play an important role in global carbon cycle because of their remarkable extension and carbon storage capacity. Soil respiration takes a major part in the carbon cycle of the ecosystems; ratio of its autotrophic and heterotrophic components is important also when considering their sensitivity to environmental drivers. The aim of the study was to estimate the contribution by root, mycorrhizal and basal components to total soil CO2 efflux. The study was carried out in the semi-arid sandy grassland dominated by Festuca pseudovina at the Kiskunság National Park in Hungary (Bugac site) where C-flux measurements have been going on since 2002. The soil CO2 effluxes were measured in the following treatments: a./ control, b./ root-exclusion, c./ root and mycorrhiza exclusion by using 80 cm long 15 cm inner diameter PVC tubes and micro-pore inox meshes. Inox mesh was used to exclude roots, but let the mycorrhiza filaments to grow into the tubes. 10 soil cores were excavated, sieved, then root-free soil was packed back layer by layer into the cores giving 6 and 4 repetitions in b and c treatments respectively. Basal respiration is referred to as the heterotrophic respiration without influence of roots or mycorrhiza. Difference between root-exclusion and root and mycorrhiza exclusion treatment gave the value of mycorrhizal respiration and control (non-disturbed) plots the total soil CO2 efflux. The contribution by the above components was evaluated. Soil CO2 efflux was measured continuously by using an automated open system of 10 soil respiration chambers. Data was collected in every two hours from each treatment (one of the chambers recorded basal respiration, 3 chambers were settled on root-excluded treatments and 6 chambers measured control plots). Chambers were moved in every 2 weeks between the repetitions of the treatments. Soil CO2 efflux (mycorrhiza-free, root free, control) data were fitted using a soil respiration model, where soil temperature, soil

  4. Carbon fluxes from an urban tropical grassland.

    Science.gov (United States)

    Ng, B J L; Hutyra, L R; Nguyen, H; Cobb, A R; Kai, F M; Harvey, C; Gandois, L

    2015-08-01

    Turfgrass covers a large fraction of the urbanized landscape, but the carbon exchange of urban lawns is poorly understood. We used eddy covariance and flux chambers in a grassland field manipulative experiment to quantify the carbon mass balance in a Singapore tropical turfgrass. We also assessed how management and variations in environmental factors influenced CO2 respiration. Standing aboveground turfgrass biomass was 80 gC m(-2), with a mean ecosystem respiration of 7.9 ± 1.1 μmol m(-2) s(-1). The contribution of autotrophic respiration was 49-76% of total ecosystem respiration. Both chamber and eddy covariance measurements suggest the system was in approximate carbon balance. While we did not observe a significant relationship between the respiration rates and soil temperature or moisture, daytime fluxes increased during the rainy interval, indicating strong overall moisture sensitivity. Turfgrass biomass is small, but given its abundance across the urban landscape, it significantly influences diurnal CO2 concentrations. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Informing agricultural management - The challenge of modelling grassland phenology

    Science.gov (United States)

    Calanca, Pierluigi

    2017-04-01

    Grasslands represent roughly 70% of the agricultural land worldwide, are the backbone of animal husbandry and contribute substantially to agricultural income. At the farm scale a proper management of meadows and pastures is necessary to attain a balance between forage production and consumption. A good hold on grassland phenology is of paramount importance in this context, because forage quantity and quality critically depend on the developmental stage of the sward. Traditionally, empirical rules have been used to advise farmers in this respect. Yet the provision of supporting information for decision making would clearly benefit from dedicated tools that integrate reliable models of grassland phenology. As with annual crops, in process-based models grassland phenology is usually described as a linear function of so-called growing degree days, whereby data from field trials and monitoring networks are used to calibrate the relevant parameters. It is shown in this contribution that while the approach can provide reasonable estimates of key developmental stages in an average sense, it fails to account for the variability observed in managed grasslands across sites and years, in particular concerning the start of the growing season. The analysis rests on recent data from western Switzerland, which serve as a benchmark for simulations carried out with grassland models of increasing complexity. Reasons for an unsatisfactory model performance and possibilities to improve current models are discussed, including the necessity to better account for species composition, late season management decisions, as well as plant physiological processes taking place during the winter season. The need to compile existing, and collect new data doe managed grasslands is also stressed.

  6. Moisture and vegetation controls on decadal-scale accrual of soil organic carbon and total nitrogen in restored grasslands

    Science.gov (United States)

    O'Brien, S. L.; Jastrow, J.D.; Grimley, D.A.; Gonzalez-Meler, M. A.

    2010-01-01

    Revitalization of degraded landscapes may provide sinks for rising atmospheric CO2, especially in reconstructed prairies where substantial belowground productivity is coupled with large soil organic carbon (SOC) deficits after many decades of cultivation. The restoration process also provides opportunities to study the often-elusive factors that regulate soil processes. Although the precise mechanisms that govern the rate of SOC accrual are unclear, factors such as soil moisture or vegetation type may influence the net accrual rate by affecting the balance between organic matter inputs and decomposition. A resampling approach was used to assess the control that soil moisture and plant community type each exert on SOC and total nitrogen (TN) accumulation in restored grasslands. Five plots that varied in drainage were sampled at least four times over two decades to assess SOC, TN, and C4- and C3-derived C. We found that higher long-term soil moisture, characterized by low soil magnetic susceptibility, promoted SOC and TN accrual, with twice the SOC and three times the TN gain in seasonally saturated prairies compared with mesic prairies. Vegetation also influenced SOC and TN recovery, as accrual was faster in the prairies compared with C3-only grassland, and C4-derived C accrual correlated strongly to total SOC accrual but C3-C did not. High SOC accumulation at the surface (0-10 cm) combined with losses at depth (10-20 cm) suggested these soils are recovering the highly stratified profiles typical of remnant prairies. Our results suggest that local hydrology and plant community are critical drivers of SOC and TN recovery in restored grasslands. Because these factors and the way they affect SOC are susceptible to modification by climate change, we contend that predictions of the C-sequestration performance of restored grasslands must account for projected climatic changes on both soil moisture and the seasonal productivity of C4 and C3 plants. ?? 2009 Blackwell

  7. Hurricane Sandy: Shared Trauma and Therapist Self-Disclosure.

    Science.gov (United States)

    Rao, Nyapati; Mehra, Ashwin

    2015-01-01

    Hurricane Sandy was one of the most devastating storms to hit the United States in history. The impact of the hurricane included power outages, flooding in the New York City subway system and East River tunnels, disrupted communications, acute shortages of gasoline and food, and a death toll of 113 people. In addition, thousands of residences and businesses in New Jersey and New York were destroyed. This article chronicles the first author's personal and professional experiences as a survivor of the hurricane, more specifically in the dual roles of provider and trauma victim, involving informed self-disclosure with a patient who was also a victim of the hurricane. The general analytic framework of therapy is evaluated in the context of the shared trauma faced by patient and provider alike in the face of the hurricane, leading to important implications for future work on resilience and recovery for both the therapist and patient.

  8. Performance of social network sensors during Hurricane Sandy.

    Directory of Open Access Journals (Sweden)

    Yury Kryvasheyeu

    Full Text Available Information flow during catastrophic events is a critical aspect of disaster management. Modern communication platforms, in particular online social networks, provide an opportunity to study such flow and derive early-warning sensors, thus improving emergency preparedness and response. Performance of the social networks sensor method, based on topological and behavioral properties derived from the "friendship paradox", is studied here for over 50 million Twitter messages posted before, during, and after Hurricane Sandy. We find that differences in users' network centrality effectively translate into moderate awareness advantage (up to 26 hours; and that geo-location of users within or outside of the hurricane-affected area plays a significant role in determining the scale of such an advantage. Emotional response appears to be universal regardless of the position in the network topology, and displays characteristic, easily detectable patterns, opening a possibility to implement a simple "sentiment sensing" technique that can detect and locate disasters.

  9. Performance of social network sensors during Hurricane Sandy.

    Science.gov (United States)

    Kryvasheyeu, Yury; Chen, Haohui; Moro, Esteban; Van Hentenryck, Pascal; Cebrian, Manuel

    2015-01-01

    Information flow during catastrophic events is a critical aspect of disaster management. Modern communication platforms, in particular online social networks, provide an opportunity to study such flow and derive early-warning sensors, thus improving emergency preparedness and response. Performance of the social networks sensor method, based on topological and behavioral properties derived from the "friendship paradox", is studied here for over 50 million Twitter messages posted before, during, and after Hurricane Sandy. We find that differences in users' network centrality effectively translate into moderate awareness advantage (up to 26 hours); and that geo-location of users within or outside of the hurricane-affected area plays a significant role in determining the scale of such an advantage. Emotional response appears to be universal regardless of the position in the network topology, and displays characteristic, easily detectable patterns, opening a possibility to implement a simple "sentiment sensing" technique that can detect and locate disasters.

  10. Public support for policies to reduce risk after Hurricane Sandy.

    Science.gov (United States)

    Greenberg, Michael R; Weiner, Marc D; Noland, Robert; Herb, Jeanne; Kaplan, Marjorie; Broccoli, Anthony J

    2014-06-01

    A phone survey was conducted in New Jersey in 2013 four months after the second of two major devastating tropical storms (Sandy in 2012 and Irene in 2011). The objective was to estimate public support for restricting land uses in flood zones, requiring housing to be built to resist storm waters, and otherwise increasing mitigation and resilience. Respondents who supported these mitigation and resilience policies disproportionately were concerned about global climate change, trusted climate scientists and the federal government, and were willing to contribute to a redevelopment program through taxes, bonds, and fees. They also tended to have collectivist and egalitarian worldviews. Half of the respondents supported at least four of the seven risk-reducing policies. How their support translates into public policy remains to be seen. Lack of willingness to personally fund these policies is an obstacle.

  11. Copper and zinc distribution coefficients for sandy aquifer materials

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Astrup, Thomas; Boddum, J. K.

    2000-01-01

    ; Zn: 6±22,800 l/kg) and correlating them to the characteristics of the aquifer material (particle size distribution, organic C content, surface area, pH) revealed good correlation with pH in the range 5.3± 8.9 (Cu: r 2=0.72; Zn: r 2=0.94). Including any other of the measured aquifer characteristics...... improved the correlation only a few percent. The results indicate that the mobility of Cu and Zn in sandy aquifers, as re¯ected in the measured Kd values, is very restricted at pH values above 6, since the relative migration velocity is less than 1%. However, at lower pH values, Zn seems to become mobile...

  12. Remediation of sandy soils using surfactant solutions and foams.

    Science.gov (United States)

    Couto, Hudson J B; Massarani, Guilio; Biscaia, Evaristo C; Sant'Anna, Geraldo L

    2009-05-30

    Remediation of sandy soils contaminated with diesel oil was investigated in bench-scale experiments. Surfactant solution, regular foams and colloidal gas aphrons were used as remediation fluids. An experimental design technique was used to investigate the effect of relevant process variables on remediation efficiency. Soils prepared with different average particle sizes (0.04-0.12 cm) and contaminated with different diesel oil contents (40-80 g/kg) were used in experiments conducted with remediation fluids. A mathematical model was proposed allowing for the determination of oil removal rate-constant (k(v)) and oil content remaining in the soil after remediation (C(of)) as well as estimation of the percentage of oil removed. Oil removal efficiencies obtained under the central experimental design conditions were 96%, 88% and 35% for aphrons, regular foams and surfactant solutions, respectively. High removal efficiencies were obtained using regular foams and aphrons, demanding small amounts of surfactant.

  13. Visual Odometry for Planetary Exploration Rovers in Sandy Terrains

    Directory of Open Access Journals (Sweden)

    Linhui Li

    2013-05-01

    Full Text Available Visual odometry provides planetary exploration rovers with accurate knowledge of their position and orientation, which needs effective feature tracking results, especially in barren sandy terrains. In this paper, a stereovision based odometry algorithm is proposed for a lunar rover, which is composed of corner extraction, feature tracking and motion estimation. First, a morphology based image enhancement method is studied to guarantee enough corners are extracted. Second, a Random Sample Consensus (RANSAC algorithm is proposed to make a robust estimation of the fundamental matrix, which is the basic and critical part of feature matching and tracking. Then, the 6 degrees of freedom rover position and orientation is estimated by the RANSAC algorithm. Finally, experiments are performed in a simulated lunar surface environment using a prototype rover, which have confirmed the feasibility and effectiveness of the proposed method.

  14. Performance of Social Network Sensors during Hurricane Sandy

    Science.gov (United States)

    Kryvasheyeu, Yury; Chen, Haohui; Moro, Esteban; Van Hentenryck, Pascal; Cebrian, Manuel

    2015-01-01

    Information flow during catastrophic events is a critical aspect of disaster management. Modern communication platforms, in particular online social networks, provide an opportunity to study such flow and derive early-warning sensors, thus improving emergency preparedness and response. Performance of the social networks sensor method, based on topological and behavioral properties derived from the “friendship paradox”, is studied here for over 50 million Twitter messages posted before, during, and after Hurricane Sandy. We find that differences in users’ network centrality effectively translate into moderate awareness advantage (up to 26 hours); and that geo-location of users within or outside of the hurricane-affected area plays a significant role in determining the scale of such an advantage. Emotional response appears to be universal regardless of the position in the network topology, and displays characteristic, easily detectable patterns, opening a possibility to implement a simple “sentiment sensing” technique that can detect and locate disasters. PMID:25692690

  15. Extraction Efficiency of Belonolaimus longicaudatus from Sandy Soil.

    Science.gov (United States)

    McSorley, R; Frederick, J J

    1991-10-01

    Numbers of Belonolaimus longicaudatus extracted from sandy soils (91-92% sand) by sieving and centrifugation were only 40-55% of those extracted by sieving and incubation on a Baermann tray. Residues normally discarded at each step of the sieving plus Baermann tray extraction procedure were examined for nematodes to obtain estimates of extraction efficiencies. For third-stage and fourth-stage juveniles, males, and females, estimates of extraction efficiency ranged from 60 to 65% in one experiment and 73 to 82% in another. Estimated extraction efficiencies for second-stage juveniles were lower (33% in one experiment, 67% in another) due to losses during sieving. When sterilized soil was seeded with known numbers of B. longicaudatus, 60% of second-stage juveniles and 68-76% of other stages were recovered. Most stages of B. longicaudatus could be extracted from these soils by sieving plus Baermann incubation with an efficiency of 60-70%.

  16. 78 FR 52560 - Hurricane Sandy Rebuilding Task Force-Rebuild-by-Design; Announcement of Selection of Design Teams

    Science.gov (United States)

    2013-08-23

    ... URBAN DEVELOPMENT Hurricane Sandy Rebuilding Task Force--Rebuild-by-Design; Announcement of Selection of Design Teams AGENCY: Hurricane Sandy Task Force, HUD. ACTION: Notice. SUMMARY: In June 2013, the Hurricane Sandy Task Force launched Rebuild by Design, a multi-stage regional design competition to...

  17. Quantifying human mobility perturbation and resilience in Hurricane Sandy.

    Science.gov (United States)

    Wang, Qi; Taylor, John E

    2014-01-01

    Human mobility is influenced by environmental change and natural disasters. Researchers have used trip distance distribution, radius of gyration of movements, and individuals' visited locations to understand and capture human mobility patterns and trajectories. However, our knowledge of human movements during natural disasters is limited owing to both a lack of empirical data and the low precision of available data. Here, we studied human mobility using high-resolution movement data from individuals in New York City during and for several days after Hurricane Sandy in 2012. We found the human movements followed truncated power-law distributions during and after Hurricane Sandy, although the β value was noticeably larger during the first 24 hours after the storm struck. Also, we examined two parameters: the center of mass and the radius of gyration of each individual's movements. We found that their values during perturbation states and steady states are highly correlated, suggesting human mobility data obtained in steady states can possibly predict the perturbation state. Our results demonstrate that human movement trajectories experienced significant perturbations during hurricanes, but also exhibited high resilience. We expect the study will stimulate future research on the perturbation and inherent resilience of human mobility under the influence of hurricanes. For example, mobility patterns in coastal urban areas could be examined as hurricanes approach, gain or dissipate in strength, and as the path of the storm changes. Understanding nuances of human mobility under the influence of such disasters will enable more effective evacuation, emergency response planning and development of strategies and policies to reduce fatality, injury, and economic loss.

  18. Glider observations and modeling of sediment transport in Hurricane Sandy

    Science.gov (United States)

    Miles, Travis; Seroka, Greg; Kohut, Josh; Schofield, Oscar; Glenn, Scott

    2015-03-01

    Regional sediment resuspension and transport are examined as Hurricane Sandy made landfall on the Mid-Atlantic Bight (MAB) in October 2012. A Teledyne-Webb Slocum glider, equipped with a Nortek Aquadopp current profiler, was deployed on the continental shelf ahead of the storm, and is used to validate sediment transport routines coupled to the Regional Ocean Modeling System (ROMS). The glider was deployed on 25 October, 5 days before Sandy made landfall in southern New Jersey (NJ) and flew along the 40 m isobath south of the Hudson Shelf Valley. We used optical and acoustic backscatter to compare with two modeled size classes along the glider track, 0.1 and 0.4 mm sand, respectively. Observations and modeling revealed full water column resuspension for both size classes for over 24 h during peak waves and currents, with transport oriented along-shelf toward the southwest. Regional model predictions showed over 3 cm of sediment eroded on the northern portion of the NJ shelf where waves and currents were the highest. As the storm passed and winds reversed from onshore to offshore on the southern portion of the domain waves and subsequently orbital velocities necessary for resuspension were reduced leading to over 3 cm of deposition across the entire shelf, just north of Delaware Bay. This study highlights the utility of gliders as a new asset in support of the development and verification of regional sediment resuspension and transport models, particularly during large tropical and extratropical cyclones when in situ data sets are not readily available.

  19. Revealing accumulation zones of plastic pellets in sandy beaches.

    Science.gov (United States)

    Moreira, Fabiana T; Balthazar-Silva, Danilo; Barbosa, Lucas; Turra, Alexander

    2016-11-01

    Microplastics such as pellets are reported worldwide on sandy beaches, and have possible direct and indirect impacts on the biota and physical characteristics of the habitats where they accumulate. Evaluations of their standing stock at different spatial scales generate data on levels of contamination. This information is needed to identify accumulation zones and the specific beach habitats and communities that are likely to be most affected. Standing stocks of plastic pellets were evaluated in 13 sandy beaches in São Paulo state, Brazil. The sampling strategy incorporated across-shore transects from coastal dunes and backshores, and vertical profiles of the accumulated pellets down to 1 m depth below the sediment surface. Accumulation zones were identified at regional (among beaches) and local (between compartments) scales. At the regional scale pellet density tended to increase at beaches on the central and southwestern coast, near ports and factories that produce and transport the largest amounts of pellets in the country. At the local scale coastal dunes showed larger accumulations of pellets than backshores. For both compartments pellets tended to occur deeper in areas where standing stocks were larger. Most of the pellets were concentrated from the surface down to 0.4 m depth, suggesting that organisms inhabiting this part of the sediment column are more exposed to the risks associated with the presence of pellets. Our findings shed light on the local and regional scales of spatial variability of microplastics and their consequences for assessment and monitoring schemes in coastal compartments. Copyright © 2016. Published by Elsevier Ltd.

  20. High-density turbidity currents: Are they sandy debris flows?

    Energy Technology Data Exchange (ETDEWEB)

    Shanmugam, G. [Mobil Exploration and Producing Technical Center, Dallas, TX (United States)

    1996-01-01

    Conventionally, turbidity currents are considered as fluidal flows in which sediment is supported by fluid turbulence, whereas debris flows are plastic flows in which sediment is supported by matrix strength, dispersive pressure, and buoyant lift. The concept of high-density turbidity current refers to high-concentration, commonly non-turbulent, flows of fluids in which sediment is supported mainly by matrix strength, dispersive pressure, and buoyant lift. The conventional wisdom that traction carpets with entrained turbulent clouds on top represent high-density turbidity currents is a misnomer because traction carpets are neither fluidal nor turbulent. Debris flows may also have entrained turbulent clouds on top. The traction carpet/debris flow and the overriding turbulent clouds are two separate entities in terms of flow rheology and sediment-support mechanism. In experimental and theoretical studies, which has linked massive sands and floating clasts to high-density turbidity currents, the term high-density turbidity current has actually been used for laminar flows. In alleviating this conceptual problem, sandy debris flow is suggested as a substitute for high-density turbidity current. Sandy debris flows represent a continuous spectrum of processes between cohesive and cohesionless debris flows. Commonly they are rheologically plastic. They may occur with or without entrained turbulent clouds on top. Their sediment-support mechanisms include matrix strength, dispersive pressure, and buoyant lift. They are characterized by laminar flow conditions, a moderate to high grain concentration, and a low to moderate mud content. Although flows evolve and transform during the course of transport in density-stratified flows, the preserved features in a deposit are useful to decipher only the final stages of deposition. At present, there are no established criteria to decipher transport mechanism from the depositional record.

  1. Mitigation of Liquefaction in Sandy Soils Using Stone Columns

    Science.gov (United States)

    Selcuk, Levent; Kayabalı, Kamil

    2010-05-01

    Soil liquefaction is one of the leading causes of earthquake-induced damage to structures. Soil improvement methods provide effective solutions to reduce the risk of soil liquefaction. Thus, soil ground treatments are applied using various techniques. However, except for a few ground treatment methods, they generally require a high cost and a lot of time. Especially in order to prevent the risk of soil liquefaction, stone columns conctructed by vibro-systems (vibro-compaction, vibro-replacement) are one of the traditional geotechnical methods. The construction of stone columns not only enhances the ability of clean sand to drain excess pore water during an earthquake, but also increases the relative density of the soil. Thus, this application prevents the development of the excess pore water pressure in sand during earthquakes and keeps the pore pressure ratio below a certain value. This paper presents the stone column methods used against soil liquefaction in detail. At this stage, (a) the performances of the stone columns were investigated in different spacing and diameters of columns during past earthquakes, (b) recent studies about design and field applications of stone columns were presented, and (c) a new design method considering the relative density of soil and the capacity of drenage of columns were explained in sandy soil. Furthermore, with this new method, earthquake performances of the stone columns constructed at different areas were investigated before the 1989 Loma Prieta and the 1994 Northbridge earthquakes, as case histories of field applications, and design charts were compiled for suitable spacing and diameters of stone columns with consideration to the different sandy soil parameters and earhquake conditions. Key Words: Soil improvement, stone column, excess pore water pressure

  2. Quantifying human mobility perturbation and resilience in Hurricane Sandy.

    Directory of Open Access Journals (Sweden)

    Qi Wang

    Full Text Available Human mobility is influenced by environmental change and natural disasters. Researchers have used trip distance distribution, radius of gyration of movements, and individuals' visited locations to understand and capture human mobility patterns and trajectories. However, our knowledge of human movements during natural disasters is limited owing to both a lack of empirical data and the low precision of available data. Here, we studied human mobility using high-resolution movement data from individuals in New York City during and for several days after Hurricane Sandy in 2012. We found the human movements followed truncated power-law distributions during and after Hurricane Sandy, although the β value was noticeably larger during the first 24 hours after the storm struck. Also, we examined two parameters: the center of mass and the radius of gyration of each individual's movements. We found that their values during perturbation states and steady states are highly correlated, suggesting human mobility data obtained in steady states can possibly predict the perturbation state. Our results demonstrate that human movement trajectories experienced significant perturbations during hurricanes, but also exhibited high resilience. We expect the study will stimulate future research on the perturbation and inherent resilience of human mobility under the influence of hurricanes. For example, mobility patterns in coastal urban areas could be examined as hurricanes approach, gain or dissipate in strength, and as the path of the storm changes. Understanding nuances of human mobility under the influence of such disasters will enable more effective evacuation, emergency response planning and development of strategies and policies to reduce fatality, injury, and economic loss.

  3. Degradation of the potato glycoalkaloid alpha-solanine in three agricultural soils.

    Science.gov (United States)

    Jensen, Pia H; Pedersen, Rasmus B; Svensmark, Bo; Strobel, Bjarne W; Jacobsen, Ole Stig; Hansen, Hans Christian B

    2009-08-01

    The toxic glycoalkaloids produced by the potato plant (Solanum tuberosum L.) have previously been found in upper soil from a potato field during several months. Further insight into the fate of the glycoalkaloids is needed, as only little information about their degradation in soil is available. Degradation of the glycoalkaloid, alpha-solanine, has been followed for 42d in three agricultural soils with common texture and carbon contents. A similar degradation pattern was found in all soils, and the kinetics was well described by a sum of two first-order equations. Overall, degradation rates for the initial first reaction were in the range 0.22-1.64d(-1). Estimated half-lives were in the range 1.8-4.1d for the three top soils at 15 degrees C; the fastest degradation was observed in the sandy soil. The major proportion of alpha-solanine in the sandy soil was degraded by the fast process, while the proportion was lower for the two other soils. Fast degradation appeared to be related to the presence of low amount of sorbents. Additionally, degradation was followed at 5 degrees C in A- and C-horizon soil from the sandy location, and for both horizons the half-lives were of similar length (4.7-8.7d). For the slow process, degradation rates were in the range 0.000-0.123d(-1), and residuals were still present in all soils and all temperatures at the end of the experiment (d 42). Overall, fast degradation was found in both top- and subsoil even at low temperatures, and the risk for alpha-solanine leaching to the groundwater appears to be low.

  4. Prescribed fire as an alternative measure in European grassland conservation

    Science.gov (United States)

    Valkó, Orsolya; Deák, Balázs; Török, Péter; Tóthmérész, Béla

    2015-04-01

    There are contrasting opinions on the perspectives of prescribed burning management in European grasslands. One hand, prescribed burning can be effectively used with relatively low implementation costs for the management of open landscapes, the reduction of accumulated litter or for decreasing the chance of wildfires. On the other hand burning can also have serious detrimental impacts on grassland ecosystems by promoting the dominance of some problem species (e.g. some competitors or invasive species) and by threatening endangered plant and animal species, especially invertebrates, thus, inappropriate burning can result in a loss of biodiversity in the long run. Our goal was to review the publications on the application of prescribed burning in European grasslands considering general (e.g. timing, frequency and duration) and specific (e.g. types of grasslands, effects on endangered species) circumstances. Even prescribed burning forms an integral part of the North-American grassland management practice, it is rarely applied in Europe, despite the fact that uncontrolled burning occurs frequently in some regions. According to the North-American experiences prescribed burning can be a viable solution for biodiversity conservation and can be a feasible solution for several nature conservation problems. We reviewed prescribed burning studies from Europe and North-America to identify findings which might be adapted to the European grassland conservation strategy. We found that not only the application of fire management is scarce in Europe but there is also a lack of published studies on this topic. European studies - contrary to the North-American practice - usually used yearly dormant-season burning, and concluded that this burning type solely is not feasible to preserve and maintain species-rich grasslands. In North-American grasslands, application of burning has a stronger historical, practical and scientific background; it is fine-tuned in terms of timing, frequency

  5. Carbon sink activity and GHG budget of managed European grasslands

    Science.gov (United States)

    Klumpp, Katja; Herfurth, Damien; Soussana, Jean-Francois; Fluxnet Grassland Pi's, European

    2013-04-01

    In agriculture, a large proportion (89%) of greenhouse gas (GHG) emission saving potential may be achieved by means of soil C sequestration. Recent demonstrations of carbon sink activities of European ecosystemes, however, often questioned the existence of C storing grasslands, as though a net sink of C was observed, uncertainty surrounding this estimate was larger than the sink itself (Janssens et al., 2003, Schulze et al., 2009. Then again, some of these estimates were based on a small number of measurements, and on models. Not surprising, there is still, a paucity of studies demonstrating the existence of grassland systems, where C sequestration would exceed (in CO2 equivalents) methane emissions from the enteric fermentation of ruminants and nitrous oxide emissions from managed soils. Grasslands are heavily relied upon for food and forage production. A key component of the carbon sink activity in grasslands is thus the impact of changes in management practices or effects of past and recent management, such as intensification as well as climate (and -variation). We analysed data (i.e. flux, ecological, management and soil organic carbon) from a network of European grassland flux observation sites (36). These sites covered different types and intensities of management, and offered the opportunity to understand grassland carbon cycling and trade-offs between C sinks and CH4 and N2O emissions. For some sites, the assessment of carbon sink activities were compared using two methods; repeated soil inventory and determination of the ecosystem C budget by continuous measurement of CO2 exchange in combination with quantification of other C imports and exports (net C storage, NCS). In general grassland, were a potential sink of C with 60±12 g C /m2.yr (median; min -456; max 645). Grazed sites had a higher NCS compared to cut sites (median 99 vs 67 g C /m2.yr), while permanent grassland sites tended to have a lower NCS compared to temporary sown grasslands (median 64 vs

  6. Climatic change controls productivity variation in global grasslands.

    Science.gov (United States)

    Gao, Qingzhu; Zhu, Wenquan; Schwartz, Mark W; Ganjurjav, Hasbagan; Wan, Yunfan; Qin, Xiaobo; Ma, Xin; Williamson, Matthew A; Li, Yue

    2016-05-31

    Detection and identification of the impacts of climate change on ecosystems have been core issues in climate change research in recent years. In this study, we compared average annual values of the normalized difference vegetation index (NDVI) with theoretical net primary productivity (NPP) values based on temperature and precipitation to determine the effect of historic climate change on global grassland productivity from 1982 to 2011. Comparison of trends in actual productivity (NDVI) with climate-induced potential productivity showed that the trends in average productivity in nearly 40% of global grassland areas have been significantly affected by climate change. The contribution of climate change to variability in grassland productivity was 15.2-71.2% during 1982-2011. Climate change contributed significantly to long-term trends in grassland productivity mainly in North America, central Eurasia, central Africa, and Oceania; these regions will be more sensitive to future climate change impacts. The impacts of climate change on variability in grassland productivity were greater in the Western Hemisphere than the Eastern Hemisphere. Confirmation of the observed trends requires long-term controlled experiments and multi-model ensembles to reduce uncertainties and explain mechanisms.

  7. Ecology and Conservation of Steppes and Semi-Natural Grasslands

    Directory of Open Access Journals (Sweden)

    Valkó Orsolya

    2016-12-01

    Full Text Available Palaearctic grasslands encompass a diverse variety of habitats, many of high nature value and vulnerability. The main challenges are climate-change, land-use change, agricultural intensification and abandonment. Many measures are in place to address these challenges, through restoration and appropriate management, though more work is necessary. We present eight studies from China/Germany, Greece, Kazakhstan, Russia and Ukraine. The papers cover a wide range of grassland and steppe habitats and cover vegetation ecology, syntaxonomy and zoology. We also conducted a systematic search on steppe and grassland diversity. The greatest number of studies was from China, followed by Germany and England. We conclude that the amount of research being carried out on Eurasian grasslands is inadequate considering their high levels of biodiversity and vulnerability. We hope to encourage readers to address current major challenges, such as how to manage grasslands for the benefit of diverse taxa, to ensure that conservation initiatives concentrate on sites where there is good potential for success and for the generation of realistic and viable conservation strategies.

  8. Classification of Grassland Successional Stages Using Airborne Hyperspectral Imagery

    Directory of Open Access Journals (Sweden)

    Thomas Möckel

    2014-08-01

    Full Text Available Plant communities differ in their species composition, and, thus, also in their functional trait composition, at different stages in the succession from arable fields to grazed grassland. We examine whether aerial hyperspectral (414–2501 nm remote sensing can be used to discriminate between grazed vegetation belonging to different grassland successional stages. Vascular plant species were recorded in 104.1 m2 plots on the island of Öland (Sweden and the functional properties of the plant species recorded in the plots were characterized in terms of the ground-cover of grasses, specific leaf area and Ellenberg indicator values. Plots were assigned to three different grassland age-classes, representing 5–15, 16–50 and >50 years of grazing management. Partial least squares discriminant analysis models were used to compare classifications based on aerial hyperspectral data with the age-class classification. The remote sensing data successfully classified the plots into age-classes: the overall classification accuracy was higher for a model based on a pre-selected set of wavebands (85%, Kappa statistic value = 0.77 than one using the full set of wavebands (77%, Kappa statistic value = 0.65. Our results show that nutrient availability and grass cover differences between grassland age-classes are detectable by spectral imaging. These techniques may potentially be used for mapping the spatial distribution of grassland habitats at different successional stages.

  9. Interannual variation in root production in grasslands affected by artificially modified amount of rainfall.

    Science.gov (United States)

    Fiala, Karel; Tůma, Ivan; Holub, Petr

    2012-01-01

    The effect of different amounts of rainfall on the below-ground plant biomass was studied in three grassland ecosystems. Responses of the lowland (dry Festuca grassland), highland (wet Cirsium grassland), and mountain (Nardus grassland) grasslands were studied during five years (2006-2010). A field experiment based on rainout shelters and gravity irrigation simulated three climate scenarios: rainfall reduced by 50% (dry), rainfall increased by 50% (wet), and the natural rainfall of the current growing season (ambient). The interannual variation in root increment and total below-ground biomass reflected the experimentally manipulated amount of precipitation and also the amount of current rainfall of individual years. The effect of year on these below-ground parameters was found significant in all studied grasslands. In comparison with dry Festuca grassland, better adapted to drought, submontane wet Cirsium grassland was more sensitive to the different water inputs forming rather lower amount of below-ground plant matter at reduced precipitation.

  10. Interannual Variation in Root Production in Grasslands Affected by Artificially Modified Amount of Rainfall

    Directory of Open Access Journals (Sweden)

    Karel Fiala

    2012-01-01

    Full Text Available The effect of different amounts of rainfall on the below-ground plant biomass was studied in three grassland ecosystems. Responses of the lowland (dry Festuca grassland, highland (wet Cirsium grassland, and mountain (Nardus grassland grasslands were studied during five years (2006–2010. A field experiment based on rainout shelters and gravity irrigation simulated three climate scenarios: rainfall reduced by 50% (dry, rainfall increased by 50% (wet, and the natural rainfall of the current growing season (ambient. The interannual variation in root increment and total below-ground biomass reflected the experimentally manipulated amount of precipitation and also the amount of current rainfall of individual years. The effect of year on these below-ground parameters was found significant in all studied grasslands. In comparison with dry Festuca grassland, better adapted to drought, submontane wet Cirsium grassland was more sensitive to the different water inputs forming rather lower amount of below-ground plant matter at reduced precipitation.

  11. Response of lizard community structure to desert grassland restoration mediated by a keystone rodent

    Science.gov (United States)

    Many grasslands in the Chihuahuan Desert have transformed to shrublands dominated by creosotebush (Larrea tridentata). Grassland restoration efforts have been directed at controlling creosotebush by applying herbicide over large spatial scales. However, we have a limited understanding of how landsca...

  12. Eruption-related lahars and sedimentation response downstream of Mount Hood: Field guide to volcaniclastic deposits along the Sandy River, Oregon

    Science.gov (United States)

    Pierson, Tom C.; Scott, William E.; Vallance, James W.; Pringle, Patrick T.; O'Connor, Jim; Dorsey, Rebecca; Madin, Ian

    2009-01-01

    Late Holocene dome-building eruptions at Mount Hood during the Timberline and Old Maid eruptive periods resulted in numerous dome-collapse pyroclastic flows and lahars that moved large volumes of volcaniclastic sediment into temporary storage in headwater canyons of the Sandy River. During each eruptive period, accelerated sediment loading to the river through erosion and remobilization of volcanic fragmental debris resulted in very high sediment-transport rates in the Sandy River during rain- and snowmelt-induced floods. Large sediment loads in excess of the river's transport capacity led to channel aggradation, channel widening, and change to a braided channel form in the lowermost reach of the river, between 61 and 87 km downstream from the volcano. The post-eruption sediment load moved as a broad bed-material wave, which in the case of the Old Maid eruption took ~2 decades to crest 83 km downstream. Maximum post-eruption aggradation levels of at least 28 and 23 m were achieved in response to Timberline and Old Maid eruptions. In each case, downstream aggradation cycles were initiated by lahars, but the bulk of the aggradation was achieved by fluvial sediment transport and deposition. When the high rates of sediment supply began to diminish, the river degraded, incising the channel fills and forming progressively lower sets of degradational terraces. A variety of debris-flow, hyperconcentrated-flow, and fluvial (upper and lower flow regime) deposits record the downstream passage of the sediment waves that were initiated by these eruptions. The deposits also presage a hazard that may be faced by communities along the Sandy River when volcanic activity at Mount Hood resumes.

  13. Restoring Tropical Grassland Productivity with Facilitated Biofertilisation

    Science.gov (United States)

    Williams, Wendy; Büdel, Burkhard

    2015-04-01

    Grazing is the major economic activity in northern Australia's subtropical grasslands, savannah and shrublands that cover >1.9 million km2 however; there has been significant decline in soil fertility that has led to the need to consider ways to improve management. Terrestrial cyanobacteria primarily inhabit complex soil microbial communities that drive physical and biological processes in the topsoil. These microbes facilitate resilience to drought and maintain soil function. They transform their environment through the secretion of mucilaginous organic compounds that improve aggregate stability, porosity, rainfall infiltration rates and water storage, reduce evaporation and soil erosion and, improve seedling emergence. In the northern Australian savannah cyanobacterial communities dominate soil surfaces of the perennial tussock grasslands. The core focus of this research has been to better understand the function of cyanobacteria within the climate-soil-plant ecosystem. The recent discovery that cyanobacteria are programmed to detect and respond only to wet season rains, and remain inactive and unproductive during the dry season even if it rains, has rewritten our understanding of soil nutrient cycles in the northern Australian savannah. In this project we have established: 1. For the wet season trials (Dec 2009-May 2010) the mean values of cyanobacterial crust (0-1 cm depth; n=100) plant-available N fluctuated, yet significantly increased incrementally from Dec to Feb (2.74 ± 0.37SE-5.62 ± 0.82 mg NH4+ kg-1 soil; p = 0.003) and peaked from Mar-May (9.59 ± 1.5SE-16.04 ± 3.2SE mg NH4+ kg-1 soil; p = 0.127) that represented the concluding stages of the wet season. 2. Cyanobacterial rates of N-fixation (determined by Acetylene Reduction assays, n=6 per month), increased significantly from the commencement to the height of the wet season (13.2 ± 2.9SE-30.2 ± 1.9SE kg N ha-1; p = 0.001) and decreased towards the end of the wet season (10.4 ± 1.8SE kg N ha-1; p

  14. Biodegradation and bioremediation potential of diazinon-degrading Serratia marcescens to remove other organophosphorus pesticides from soils.

    Science.gov (United States)

    Cycoń, Mariusz; Żmijowska, Agnieszka; Wójcik, Marcin; Piotrowska-Seget, Zofia

    2013-03-15

    The ability of diazinon-degrading Serratia marcescens to remove organophosphorus pesticides (OPPs), i.e. chlorpyrifos (CP), fenitrothion (FT), and parathion (PT) was studied in a mineral salt medium (MSM) and in three soils of different characteristics. This strain was capable of using all insecticides at concentration of 50 mg/l as the only carbon source when grown in MSM, and 58.9%, 70.5%, and 82.5% of the initial dosage of CP, FT, and PT, respectively was degraded within 14 days. The biodegradation experiment showed that autochthonous microflora in all soils was characterized by a degradation potential of all tested OPPs; however, the initial lag phases for degradation of CP and FT, especially in sandy soil, were observed. During the 42-day experiment, 45.3%, 61.4% and 72.5% of the initial dose of CP, FT, and PT, respectively, was removed in sandy soil whereas the degradation of CP, FT, and PT in the same period, in sandy loam and silty soils reached 61.4%, 79.7% and 64.2%, and 68.9%, 81.0% and 63.6%, respectively. S. marcescens introduced into sterile soils showed a higher degradation potential (5-13%) for OPPs removal than those observed in non-sterile soil with naturally occurring attenuation. Inoculation of non-sterile soils with S. marcescens enhanced the disappearance rates of all insecticides, and DT50 for CP, FT, and PT was reduced by 20.7, 11.3 and 13.0 days, and 11.9, 7.0 and 8.1 days, and 9.7, 14.5 and 12.6 days in sandy, sandy loam, and silty soils, respectively, in comparison with non-sterile soils with only indigenous microflora. This ability of S. marcescens makes it a suitable strain for bioremediation of soils contaminated with OPPs.

  15. Exotic flora of some grasslands of Nilgiris with their medicinal uses

    OpenAIRE

    S Paulsamy; Suresh, D.

    2007-01-01

    In addition to the dominance of indigenous plant species, the grasslands of Nilgiris harbour a considerable number of exotic plants with sizeable number of individuals. In the present study in four major grasslands of Nilgiris, out of 12 exotic species present, 10 are recognized as medicinally important. The family, Asteraceae contributed a higher number of 6 medicinal species to the grassland community. The density of exotics in the studied grasslands is varied between 4 and 66/ha. In order ...

  16. Land degradation monitoring using time-series MODIS and TM data

    Science.gov (United States)

    Yuan, Jinguo; Niu, Zheng; Long, Limin; Xu, Jingjing

    2007-11-01

    Land degradation is one of the serious environmental problems that can lead to poverty. North Hebei province is one part of eco-fragile region in North China, and is a transitional zone from farming to forest and grassland. This paper evaluated land degradation of North Hebei province from 1987 to 2001. Remote sensing data were time-series MODIS 500m 8-day surface reflectance and 16-day EVI product in 2001 and Landsat TM data in 1987 and 2000. TM and MODIS data were processed in ERDAS and ModisTool software including projection transformation and subset. Degradation evaluation indices, including enhanced vegetation index (EVI), land surface water index (LSWI) and modified soil adjusted vegetation index (MSAVI) of three subregions were calculated. Results showed that the total land degradation area was 64439km2 in 2001, of which high and severe land degradation level area were 20734km2 and 3948km2, accounting for 32.18% and 6.13%, respectively. Low land degradation level appeared in Yanshan mountainous area; medium land degradation level mainly appeared in Bashang plateau region, where vegetation types were cultivated land and grassland, and high land degradation level mainly appeared in Bashang plateau region and the basin area, where grass land degradation and soil erosion were serious.

  17. Avoidance of unconventional oil wells and roads exacerbates habitat loss for grassland birds in the North American great plains

    Science.gov (United States)

    Thompson, Sarah J.; Johnson, Douglas H.; Nieumuth, Neal; Ribic, Christine

    2015-01-01

    Oil development in the Bakken shale region has increased rapidly as a result of new technologies and strong demand for fossil fuel. This region also supports a particularly high density and diversity of grassland bird species, which are declining across North America. We examined grassland bird response to unconventional oil extraction sites (i.e. developed with hydraulic fracturing and horizontal drilling techniques) and associated roads in North Dakota. Our goal was to quantify the amount of habitat that was indirectly degraded by oil development, as evidenced by patterns of avoidance by birds. Grassland birds avoided areas within 150 m of roads (95% CI: 87–214 m), 267 m of single-bore well pads (95% CI: 157–378 m), and 150 m of multi-bore well pads (95% CI: 67–233 m). Individual species demonstrated variable tolerance of well pads. Clay-colored sparrows (Spizella pallida) were tolerant of oil-related infrastructure, whereas Sprague's pipit (Anthus spragueii) avoided areas within 350 m (95% CI: 215–485 m) of single-bore well pads. Given these density patterns around oil wells, the potential footprint of any individual oil well, and oil development across the region, is greatly multiplied for sensitive species. Efforts to reduce new road construction, concentrate wells along developed corridors, combine numerous wells on multi-bore pads rather than build many single-bore wells, and to place well pads near existing roads will serve to minimize loss of suitable habitat for birds. Quantifying environmental degradation caused by oil development is a critical step in understanding how to better mitigate harm to wildlife populations.

  18. Nitrogen deposition threatens species richness of grasslands across Europe

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, C.J. [Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ (United Kingdom); Gowing, D.J.G. [Department of Life Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Dupre, C.; Diekmann, M. [Institute of Ecology, FB 2, University of Bremen, Leobener Str., DE-28359 Bremen (Germany); Dorland, E. [Section of Landscape Ecology, Department of Geobiology, Utrecht University, P.O. Box 80084, 3508 TB Utrecht (Netherlands); Gaudnik, C.; Alard, D.; Corcket, E. [University of Bordeaux 1. UMR INRA 1202 Biodiversity, Genes and Communities, Equipe Ecologie des Communautes, Batiment B8 - Avenue des Facultes, F-33405 Talence (France); Bleeker, A. [Department of Air Quality and Climate Change, Energy Research Centre of the Netherlands, P.O. Box 1, 1755 ZG Petten (Netherlands); Bobbink, R. [B-WARE Research Centre, Radboud University, P.O. Box 9010, 6525 ED Nijmegen (Netherlands); Fowler, D. [NERC Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian EH26 0QB (United Kingdom); Mountford, J.O. [NERC Centre for Ecology and Hydrology, MacLean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxfordshire OX10 8BB (United Kingdom); Vandvik, V. [Department of Biology, University of Bergen, Box 7800, N-5020 Bergen (Norway); Aarrestad, P.A. [Norwegian Institute for Nature Research, NO-7485 Trondheim (Norway); Muller, S. [Laboratoire des Interactions Ecotoxicologie, Biodiversite et Ecosystemes LIEBE, UMR CNRS 7146, U.F.R. Sci. F.A., Campus Bridoux, Universite Paul Verlaine, Avenue du General Delestraint, F-57070 Metz (France); Dise, N.B. [Department of Environmental and Geographical Science, Manchester Metropolitan University, Manchester M1 5GD (United Kingdom)

    2010-09-15

    Evidence from an international survey in the Atlantic biogeographic region of Europe indicates that chronic nitrogen deposition is reducing plant species richness in acid grasslands. Across the deposition gradient in this region (2-44 kg N ha{sup -1} yr{sup -1}) species richness showed a curvilinear response, with greatest reductions in species richness when deposition increased from low levels. This has important implications for conservation policies, suggesting that to protect the most sensitive grasslands resources should be focussed where deposition is currently low. Soil pH is also an important driver of species richness indicating that the acidifying effect of nitrogen deposition may be contributing to species richness reductions. The results of this survey suggest that the impacts of nitrogen deposition can be observed over a large geographical range. Atmospheric nitrogen deposition is reducing biodiversity in grasslands across Europe.

  19. Assessing the Effects of Grassland Management on Forage Production and Environmental Quality to Identify Paths to Ecological Intensification in Mountain Grasslands

    Science.gov (United States)

    Loucougaray, Grégory; Dobremez, Laurent; Gos, Pierre; Pauthenet, Yves; Nettier, Baptiste; Lavorel, Sandra

    2015-11-01

    Ecological intensification in grasslands can be regarded as a process for increasing forage production while maintaining high levels of ecosystem functions and biodiversity. In the mountain Vercors massif, where dairy cattle farming is the main component of agriculture, how to achieve forage autonomy at farm level while sustaining environmental quality for tourism and local dairy products has recently stimulated local debate. As specific management is one of the main drivers of ecosystem functioning, we assessed the response of forage production and environmental quality at grassland scale across a wide range of management practices. We aimed to determine which components of management can be harnessed to better match forage production and environmental quality. We sampled the vegetation of 51 grasslands stratified across 13 grassland types. We assessed each grassland for agronomic and environmental properties, measuring forage production, forage quality, and indices based on the abundance of particular plant species such as timing flexibility, apiarian potential, and aromatic plants. Our results revealed an expected trade-off between forage production and environmental quality, notably by stressing the contrasts between sown and permanent grasslands. However, strong within-type variability in both production and environmental quality as well as in flexibility of timing of use suggests possible ways to improve this trade-off at grassland and farm scales. As achieving forage autonomy relies on increasing both forage production and grassland resilience, our results highlight the critical role of the ratio between sown and permanent grasslands as a major path for ecological intensification in mountain grasslands.

  20. Assessing the Effects of Grassland Management on Forage Production and Environmental Quality to Identify Paths to Ecological Intensification in Mountain Grasslands.

    Science.gov (United States)

    Loucougaray, Grégory; Dobremez, Laurent; Gos, Pierre; Pauthenet, Yves; Nettier, Baptiste; Lavorel, Sandra

    2015-11-01

    Ecological intensification in grasslands can be regarded as a process for increasing forage production while maintaining high levels of ecosystem functions and biodiversity. In the mountain Vercors massif, where dairy cattle farming is the main component of agriculture, how to achieve forage autonomy at farm level while sustaining environmental quality for tourism and local dairy products has recently stimulated local debate. As specific management is one of the main drivers of ecosystem functioning, we assessed the response of forage production and environmental quality at grassland scale across a wide range of management practices. We aimed to determine which components of management can be harnessed to better match forage production and environmental quality. We sampled the vegetation of 51 grasslands stratified across 13 grassland types. We assessed each grassland for agronomic and environmental properties, measuring forage production, forage quality, and indices based on the abundance of particular plant species such as timing flexibility, apiarian potential, and aromatic plants. Our results revealed an expected trade-off between forage production and environmental quality, notably by stressing the contrasts between sown and permanent grasslands. However, strong within-type variability in both production and environmental quality as well as in flexibility of timing of use suggests possible ways to improve this trade-off at grassland and farm scales. As achieving forage autonomy relies on increasing both forage production and grassland resilience, our results highlight the critical role of the ratio between sown and permanent grasslands as a major path for ecological intensification in mountain grasslands.

  1. Degradation of plant cuticles in soils: impact on formation and sorptive ability of humin-mineral matrices.

    Science.gov (United States)

    Olshansky, Yaniv; Polubesova, Tamara; Chefetz, Benny

    2015-05-01

    Plant cuticles are important precursors for soil organic matter, in particular for soil humin, which is considered an efficient sorbent for organic pollutants. In this study, we examined degradation and transformation of cuticles isolated from fruit and leaves in loamy sand and sandy clay loessial arid brown soils. We then studied sorption of phenanthrene and carbamazepine to humin-mineral matrices isolated from the incubated soils. Low degradation (22%) was observed for agave cuticle in a sandy clay soil system, whereas high degradation (68-78%) was obtained for agave cuticle in a loamy sand soil system and for loamy sand and sandy clay soils amended with tomato cuticle. During incubation, most of the residual organic matter was accumulated in the humin fraction. Sorption of phenanthrene was significantly higher for humin-mineral matrices obtained from soils incubated with plant cuticles as compared with soils without cuticle application. Sorption of carbamazepine to humin-mineral matrices was not affected by cuticle residues. Cooperative sorption of carbamazepine on humin-mineral matrices isolated from sandy clay soil is suggested. Sorption-desorption hysteresis of both phenanthrene and carbamazepine was lower for humin-mineral matrices obtained from soils incubated with plant cuticles as compared with nonamended soils. Our results show that cuticle composition significantly affects the rate and extent of cuticle degradation in soils and that plant cuticle application influences sorption and desorption of polar and nonpolar pollutants by humin-mineral matrices.

  2. Productivity of North American grasslands is increased under future climate scenarios despite rising aridity

    Science.gov (United States)

    Grassland productivity is regulated by both temperature and the amount and timing of precipitation. Future climate change is therefore expected to influence grassland phenology and growth, with consequences for ecosystems and economies. However, the potential response of grasslands to climate change...

  3. Energy potential of biomass from conservation grasslands in Minnesota, USA.

    Science.gov (United States)

    Jungers, Jacob M; Fargione, Joseph E; Sheaffer, Craig C; Wyse, Donald L; Lehman, Clarence

    2013-01-01

    Perennial biomass from grasslands managed for conservation of soil and biodiversity can be harvested for bioenergy. Until now, the quantity and quality of harvestable biomass from conservation grasslands in Minnesota, USA, was not known, and the factors that affect bioenergy potential from these systems have not been identified. We measured biomass yield, theoretical ethanol conversion efficiency, and plant tissue nitrogen (N) as metrics of bioenergy potential from mixed-species conservation grasslands harvested with commercial-scale equipment. With three years of data, we used mixed-effects models to determine factors that influence bioenergy potential. Sixty conservation grassland plots, each about 8 ha in size, were distributed among three locations in Minnesota. Harvest treatments were applied annually in autumn as a completely randomized block design. Biomass yield ranged from 0.5 to 5.7 Mg ha(-1). May precipitation increased biomass yield while precipitation in all other growing season months showed no affect. Averaged across all locations and years, theoretical ethanol conversion efficiency was 450 l Mg(-1) and the concentration of plant N was 7.1 g kg(-1), both similar to dedicated herbaceous bioenergy crops such as switchgrass. Biomass yield did not decline in the second or third year of harvest. Across years, biomass yields fluctuated 23% around the average. Surprisingly, forb cover was a better predictor of biomass yield than warm-season grass with a positive correlation with biomass yield in the south and a negative correlation at other locations. Variation in land ethanol yield was almost exclusively due to variation in biomass yield rather than biomass quality; therefore, efforts to increase biomass yield might be more economical than altering biomass composition when managing conservation grasslands for ethanol production. Our measurements of bioenergy potential, and the factors that control it, can serve as parameters for assessing the economic

  4. Energy potential of biomass from conservation grasslands in Minnesota, USA.

    Directory of Open Access Journals (Sweden)

    Jacob M Jungers

    Full Text Available Perennial biomass from grasslands managed for conservation of soil and biodiversity can be harvested for bioenergy. Until now, the quantity and quality of harvestable biomass from conservation grasslands in Minnesota, USA, was not known, and the factors that affect bioenergy potential from these systems have not been identified. We measured biomass yield, theoretical ethanol conversion efficiency, and plant tissue nitrogen (N as metrics of bioenergy potential from mixed-species conservation grasslands harvested with commercial-scale equipment. With three years of data, we used mixed-effects models to determine factors that influence bioenergy potential. Sixty conservation grassland plots, each about 8 ha in size, were distributed among three locations in Minnesota. Harvest treatments were applied annually in autumn as a completely randomized block design. Biomass yield ranged from 0.5 to 5.7 Mg ha(-1. May precipitation increased biomass yield while precipitation in all other growing season months showed no affect. Averaged across all locations and years, theoretical ethanol conversion efficiency was 450 l Mg(-1 and the concentration of plant N was 7.1 g kg(-1, both similar to dedicated herbaceous bioenergy crops such as switchgrass. Biomass yield did not decline in the second or third year of harvest. Across years, biomass yields fluctuated 23% around the average. Surprisingly, forb cover was a better predictor of biomass yield than warm-season grass with a positive correlation with biomass yield in the south and a negative correlation at other locations. Variation in land ethanol yield was almost exclusively due to variation in biomass yield rather than biomass quality; therefore, efforts to increase biomass yield might be more economical than altering biomass composition when managing conservation grasslands for ethanol production. Our measurements of bioenergy potential, and the factors that control it, can serve as parameters for assessing

  5. Polysaccharide Degradation

    Science.gov (United States)

    Stone, Bruce A.; Svensson, Birte; Collins, Michelle E.; Rastall, Robert A.

    An overview of current and potential enzymes used to degrade polysaccharides is presented. Such depolymerases are comprised of glycoside hydrolases, glycosyl transferases, phosphorylases and lyases, and their classification, active sites and action patterns are discussed. Additionally, the mechanisms that these enzymes use to cleave glycosidic linkages is reviewed as are inhibitors of depolymerase activity; reagents which react with amino acid residues, glycoside derivatives, transition state inhibitors and proteinaceous inhibitors. The characterization of various enzymes of microbial, animal or plant origin has led to their widespread use in the production of important oligosaccharides which can be incorporated into food stuffs. Sources of polysaccharides of particular interest in this chapter are those from plants and include inulin, dextran, xylan and pectin, as their hydrolysis products are purported to be functional foods in the context of gastrointestinal health. An alternative use of degraded polysaccharides is in the treatment of disease. The possibility exists to treat bacterial exopolysaccharide with lyases from bacteriophage to produce oligosaccharides exhibiting bioactive sequences. Although this area is currently in its infancy the knowledge is available to investigate further.

  6. Effects of haying on breeding birds in CRP grasslands

    Science.gov (United States)

    Igl, Lawrence D.; Johnson, Douglas H.

    2016-01-01

    The Conservation Reserve Program (CRP) is a voluntary program that is available to agricultural producers to help protect environmentally sensitive or highly erodible land. Management disturbances of CRP grasslands generally are not allowed unless authorized to provide relief to livestock producers during severe drought or a similar natural disaster (i.e., emergency haying and grazing) or to improve the quality and performance of the CRP cover (i.e., managed haying and grazing). Although CRP grasslands may not be hayed or grazed during the primary bird-nesting season, these disturbances may have short-term (1 yr after disturbance) and long-term (≥2 yr after disturbance) effects on grassland bird populations. We assessed the effects of haying on 20 grassland bird species in 483 CRP grasslands in 9 counties of 4 states in the northern Great Plains, USA between 1993 and 2008. We compared breeding bird densities (as determined by total-area counts) in idle and hayed fields to evaluate changes 1, 2, 3, and 4 years after haying. Haying of CRP grasslands had either positive or negative effects on grassland birds, depending on the species, the county, and the number of years after the initial disturbance. Some species (e.g., horned lark [Eremophila alpestris], bobolink [Dolichonyx oryzivorus]) responded positively after haying, and others (e.g., song sparrow [Melospiza melodia]) responded negatively. The responses of some species changed direction as the fields recovered from haying. For example, densities for common yellowthroat (Geothlypis trichas), sedge wren (Cistothorus platensis), and clay-colored sparrow (Spizella pallida) declined the first year after haying but increased in the subsequent 3 years. Ten species showed treatment × county interactions, indicating that the effects of haying varied geographically. This long-term evaluation on the effects of haying on breeding birds provides important information on the strength and direction of changes in

  7. Bifurcation analysis of a forest-grassland ecosystem

    Science.gov (United States)

    Russo, Lucia; Spiliotis, Konstantinos G.

    2016-06-01

    The nonlinear analysis of a forest-grassland ecosystem is performed as the main system parameters are changed. The model consists of a couple of nonlinear ordinary differential equations which include dynamically the human perceptions of forest/grassland value. The system displays multiple steady states corresponding to different forest densities as well as periodic regimes characterized by oscillations in time. We performed the bifurcation analysis of the system as the parameter relative to the human opinions influence is changed. We found that the main mechanisms which regulate the transitions occurring between different states or the appearance of new steady and dynamic regimes are transcritical, saddle/node and Hopf bifurcations.

  8. Content Analysis of Select YouTube Postings: Comparisons of Reactions to the Sandy Hook and Aurora Shootings and Hurricane Sandy.

    Science.gov (United States)

    Miller, Eric D

    2015-11-01

    This study details an innovative and methodical content analysis of 2,207 YouTube comments from four different YouTube videos (e.g., breaking news or memorials) related to the 2012 Sandy Hook Elementary School and Aurora theater mass shootings and the catastrophic Hurricane Sandy. As expected, YouTube comments associated with the Sandy Hook shootings (particularly those from a memorial video) were especially likely to feature compassion and grief with lessened hostility. This study highlights differing online contexts by which individuals show grief and related emotions following man-made and natural calamities and how-even in an online environment-powerful situational contexts greatly guide behavior.

  9. Does thermal carbonization (Biochar of organic material increase more merits for their amendments of sandy soil?

    Directory of Open Access Journals (Sweden)

    Y. Wu

    2014-02-01

    Full Text Available Organic materials (e.g. furfural residue are generally believed to improve the physical and chemical properties of the soils with low fertility. Recently, biochar have been received more attention as a possible measure to improve the carbon balance and improve soil quality in some degraded soils. However, little is known about their different amelioration of a sandy saline soil. In this study, 56d incubation experiment was conducted to evaluate the influence of furfural and its biochar on the properties of saline soil. The results showed that both furfural and biochar greatly reduced pH, increased soil organic carbon (SOC content and cation exchange capacity (CEC, and enhanced the available phosphorus (P in the soil. Furfural is more efficient than biochar in reducing pH: 5% furfural lowered the soil pH by 0.5–0.8 (soil pH: 8.3–8.6, while 5% biochar decreased by 0.25–0.4 due to the loss of acidity in pyrolysis process. With respect to available P, 5% of the furfural addition increased available P content by 4–6 times in comparison to 2–5 times with biochar application. In reducing soil exchangeable sodium percentage (ESP, biochar is slightly superior to furfural because soil ESP reduced by 51% and 43% with 5% furfural and 5% biochar addition at the end of incubation. In addition, no significant differences were observed between furfural and biochar about their capacity to retain N, P in leaching solution and to increase CEC in soil. These facts may be caused by the relatively short incubation time. In general, furfural and biochar have different amendments depending on soil properties: furfural was more effectively to decrease pH and to increase available P, whereas biochar played a more important role in increasing SOC and reducing ESP of saline soil.

  10. Methodology for the elaboration of Natura 2000 sites designation acts in the Walloon Region (Belgium: calcareous grasslands in the Lesse-and-Lomme area

    Directory of Open Access Journals (Sweden)

    Mahy G.

    2005-01-01

    Full Text Available In the Walloon Region (Belgium, 239 sites have been selected to be included in the Natura 2000 network. The next step is to write designation acts in order to legally protect these 221,000 ha. In this pilot study, a designation act was elaborated for a Natura 2000 site of 2,569 ha and located in the Lesse-and-Lomme area within the Calestienne region. Although the site includes 40 ha of calcareous grasslands, characterised by an exceptional flora and fauna, this habitat is very threatened by abandonment and fragmentation.The methodology used to elaborate the designation act is presented with respect to calcareous grassland. Firstly, in spring and summer 2003, an accurate map of natural habitats was produced, with every single patch of calcareous grassland being mapped. Information was also collected in order to evaluate conservation status. Based on this information, conservation status was then assessed with respect to three different criteria: (1 integrity of the cortege species, (2 habitat structure and (3 degradations. Thirdly, the site was divided into objective zones according to the different habitats and species of Community interest found in the site. Hence, an objective zone was delineated for calcareous grasslands. This objective zone was then divided in several management units. Finally, at these different spatial levels (site, objective zone, management unit, management measures were suggested. As a result, in the draft designation act, the target is to maintain or restore 230 ha of calcareous grassland, instead of the existing 40 ha. This ambitious target requires large-scale restoration and an efficient grazing scheme. These will need important resources for their successful implementation

  11. EAARL-B Topography-Big Thicket National Preserve: Big Sandy Creek Corridor Unit, Texas, 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare-earth topography Digital Elevation Model (DEM) mosaic for the Big Sandy Creek Corridor Unit of Big Thicket National Preserve in Texas was produced from...

  12. EAARL-B Topography-Big Thicket National Preserve: Big Sandy Creek Corridor Unit, Texas, 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare-earth topography Digital Elevation Model (DEM) mosaic for the Big Sandy Creek Corridor Unit of Big Thicket National Preserve in Texas was produced from...

  13. 78 FR 19357 - Allocation of Public Transportation Emergency Relief Funds in Response to Hurricane Sandy

    Science.gov (United States)

    2013-03-29

    ... significant spending cuts known as sequestration and is unavailable for Hurricane Sandy disaster relief. The... January 29, 2013. FTA announced individual allocations on a rolling basis beginning March 6, 2013. Table...

  14. 2012-2013 Post-Hurricane Sandy EAARL-B Submerged Topography - Barnegat Bay, New Jersey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Binary point-cloud data for part of Barnegat Bay, New Jersey, post-Hurricane Sandy (October 2012 hurricane), were produced from remotely sensed, geographically...

  15. EAARL-B Topography-Big Thicket National Preserve: Big Sandy Creek Unit, Texas, 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare-earth topography digital elevation model (DEM) mosaic for the Big Sandy Creek Unit of Big Thicket National Preserve in Texas, was produced from remotely...

  16. EAARL-B Topography-Big Thicket National Preserve: Big Sandy Creek Unit, Texas, 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A first-surface topography digital elevation model (DEM) mosaic for the Big Sandy Creek Unit of Big Thicket National Preserve in Texas, was produced from remotely...

  17. EAARL-B Topography-Big Thicket National Preserve: Big Sandy Creek Corridor Unit, Texas, 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A first-surface topography Digital Elevation Model (DEM) mosaic for the Big Sandy Creek Corridor Unit of Big Thicket National Preserve in Texas was produced from...

  18. 2014 U.S. Geological Survey CMGP LiDAR: Post Sandy (New Jersey)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — TASK NAME: USGS New Jersey CMGP Sandy Lidar 0.7 Meter NPS LIDAR lidar Data Acquisition and Processing Production Task USGS Contract No. G10PC00057 Task Order No....

  19. 2014 NOAA Ortho-rectified Mosaic of Hurricane Sandy Coastal Impact Area

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles at 0.35m GSD created for NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative in Hurricane Sandy coastal...

  20. Quantitative Retrieval of Soil Nutrient in Sandy Land Based on BJ-1 Multispectral Image

    Science.gov (United States)

    Wu, Junjun; Li, Zengyuan; Gao, Zhihai; Wang, Bengyu; Bai, Lina; Sun, Bin; Li, Changlong; Ding, Xiangyuan

    2014-11-01

    To research an indicator for sandy information, this paper conducts a study on soil nutrient in sandy land. Firstly, the difference of soil nutrient between sandy land and the other was analyzed. Secondly, the correlation between soil nutrient index and band was studied. Then the best inversion band and model was determined and evaluated. Finally, the distribution of soil nutrient was obtained. As the result indicated that the divergence of total nitrogen in different land was the maximum among the three nutrient indicators. With the development of desertification, total nitrogen declined dramatically. The correlation coefficient between each band and total nitrogen was relatively higher, and it reached 0.6. In addition, taking the reciprocal for the sum of three bands as the independent variable was an excellent choice, it could reflect the sandy information better than the single band. The quantitative retrieval model was checked by independent sample, and RMSE was 0.0407.

  1. 2012 USGS EAARL-B Coastal Topography: Post-Sandy, First Surface (NJ)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — ASCII xyz and binary point-cloud data, as well as a digital elevation model (DEM) of a portion of the New Jersey coastline, pre- and post-Hurricane Sandy (October...

  2. EAARL-B Topography-Big Thicket National Preserve: Big Sandy Creek Unit, Texas, 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A first-surface topography digital elevation model (DEM) mosaic for the Big Sandy Creek Unit of Big Thicket National Preserve in Texas, was produced from remotely...

  3. EAARL-B Topography-Big Thicket National Preserve: Big Sandy Creek Corridor Unit, Texas, 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A first-surface topography Digital Elevation Model (DEM) mosaic for the Big Sandy Creek Corridor Unit of Big Thicket National Preserve in Texas was produced from...

  4. EAARL-B Topography-Big Thicket National Preserve: Big Sandy Creek Unit, Texas, 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare-earth topography digital elevation model (DEM) mosaic for the Big Sandy Creek Unit of Big Thicket National Preserve in Texas, was produced from remotely...

  5. Linkages between land Cover, enzymes, and soil organic matter chemistry following encroachment of leguminous woody plant into grasslands

    Science.gov (United States)

    Filley, T. R.; Stott, D. E.; Boutton, T. W.; Creamer, C. A.; Olk, D.

    2009-12-01

    In the Rio Grande Plains of southern Texas, subtropical thorn woodlands dominated by the N-fixing tree Prosopis glandulosa have largely replaced native grasslands over the last 150 years as a result of fire suppression and over grazing. This land cover change has resulted in the increase of belowground stocks of C, N, and P, changes to the amount and chemical nature of soil-stabilized plant biopolymers, and the composition and activity of soil microbes. Given that extracellular enzymes produced by plants and microbes are the principal means by which complex compounds are degraded and the production of such enzymes is triggered or suppressed by changes in primary input and nutrient availability we sought to relate how these fundamental changes in this ecosystem are reflected in the activity of soil stabilized extracellular enzymes and soil organic matter (SOM) chemistry in this system. We focused upon a successional chronosequence from C4-dominant grassland to woody patches of up to 86 yrs age since mesquite establishment. We related the molecular composition and concentration of hydrolysable amino acids and amino sugars, as well as CuO extractable lignin and substituted fatty acid to the potential activities of five extracellular enzymes (arylamidase, acid phosphatase, β-glucosidase, β-glucosaminidase (NAGase, polyphenoloxidase (PPO)) and a general marker for hydrolytic activity, fluorescein diacetate (FDA). Each of these enzymes, with the exception of PPO, showed higher potential activity in soils from woody clusters than grasslands and had activities generally well correlated to carbon content. PPO, often defined as a proxy for microbial lignin decay activity, showed no statistical difference between grassland and forest sites and no significant relationship to soil C content. Yields of total amino acids and amino sugars all show increases in content with cluster age when normalized to soil mass, as did the enzyme activities targeted to their decomposition, but

  6. Colonization dynamics of ciliate morphotypes modified by shifting sandy sediments.

    Science.gov (United States)

    Risse-Buhl, Ute; Felsmann, Katja; Mutz, Michael

    2014-08-01

    Sandy stream-bed sediments colonized by a diverse ciliate community are subject to various disturbance regimes. In microcosms, we investigated the effect of sediment shifting on the colonization dynamics of 3 ciliate morphotypes differing in morphology, behavior and feeding strategy. The dynamics of the ciliate morphotypes inhabiting sediment pore water and overlying water were observed at 3 sediment shifting frequencies: (1) stable sediments, (2) periodically shifting sediments such as migrating ripples, and (3) continuously shifting sediments as occurring during scour events of the uppermost sediment. Sediment shifting significantly affected the abundance and growth rate of the ciliate morphotypes. The free-swimming filter feeder Dexiostoma campylum was vulnerable to washout by sediment shifting since significantly higher numbers occurred in the overlying water than in pore water. Abundance of D. campylum only increased in pore water of stable sediments. On the contrary, the vagile grasper feeder Chilodonella uncinata and the sessile filter feeder Vorticella convallaria had positive growth rates and successfully colonized sediments that shifted periodically and continuously. Thus, the spatio-temporal pattern of sediment dynamics acts as an essential factor of impact on the structure, distribution and function of ciliate communities in sand-bed streams.

  7. Water Infiltration and Hydraulic Conductivity in Sandy Cambisols

    DEFF Research Database (Denmark)

    Bens, Oliver; Wahl, Niels Arne; Fischer, Holger

    2006-01-01

    Soil hydrological properties like infiltration capacity and hydraulic conductivity have important consequences for hydrological properties of soils in river catchments and for flood risk prevention. They are dynamic properties due to varying land use management practices. The objective of this st......Soil hydrological properties like infiltration capacity and hydraulic conductivity have important consequences for hydrological properties of soils in river catchments and for flood risk prevention. They are dynamic properties due to varying land use management practices. The objective...... of this study was to characterize the variation of infiltration capacity, hydraulic conductivity and soil organoprofile development on forest sites with comparable geological substrate, soil type and climatic conditions, but different stand ages and tree species in terms of the effects of forest transformation...... from pure Scots pine stands towards pure European beech stands. The water infiltration capacity and hydraulic conductivity (K) of the investigated sandy-textured soils are low and very few macropores exist. Additionally these pores are marked by poor connectivity and therefore do not have any...

  8. Evaluation of the Intel Sandy Bridge-EP server processor

    CERN Document Server

    Jarp, S; Leduc, J; Nowak, A; CERN. Geneva. IT Department

    2012-01-01

    In this paper we report on a set of benchmark results recently obtained by CERN openlab when comparing an 8-core “Sandy Bridge-EP” processor with Intel’s previous microarchitecture, the “Westmere-EP”. The Intel marketing names for these processors are “Xeon E5-2600 processor series” and “Xeon 5600 processor series”, respectively. Both processors are produced in a 32nm process, and both platforms are dual-socket servers. Multiple benchmarks were used to get a good understanding of the performance of the new processor. We used both industry-standard benchmarks, such as SPEC2006, and specific High Energy Physics benchmarks, representing both simulation of physics detectors and data analysis of physics events. Before summarizing the results we must stress the fact that benchmarking of modern processors is a very complex affair. One has to control (at least) the following features: processor frequency, overclocking via Turbo mode, the number of physical cores in use, the use of logical cores ...

  9. Extraction of sandy bedforms features through geodesic morphometry

    Science.gov (United States)

    Debese, Nathalie; Jacq, Jean-José; Garlan, Thierry

    2016-09-01

    State-of-art echosounders reveal fine-scale details of mobile sandy bedforms, which are commonly found on continental shelfs. At present, their dynamics are still far from being completely understood. These bedforms are a serious threat to navigation security, anthropic structures and activities, placing emphasis on research breakthroughs. Bedform geometries and their dynamics are closely linked; therefore, one approach is to develop semi-automatic tools aiming at extracting their structural features from bathymetric datasets. Current approaches mimic manual processes or rely on morphological simplification of bedforms. The 1D and 2D approaches cannot address the wide ranges of both types and complexities of bedforms. In contrast, this work attempts to follow a 3D global semi-automatic approach based on a bathymetric TIN. The currently extracted primitives are the salient ridge and valley lines of the sand structures, i.e., waves and mega-ripples. The main difficulty is eliminating the ripples that are found to heavily overprint any observations. To this end, an anisotropic filter that is able to discard these structures while still enhancing the wave ridges is proposed. The second part of the work addresses the semi-automatic interactive extraction and 3D augmented display of the main lines structures. The proposed protocol also allows geoscientists to interactively insert topological constraints.

  10. Simulations and Visualizations of Hurricane Sandy (2012) as Revealed by the NASA CAMVis

    Science.gov (United States)

    Shen, Bo-Wen

    2013-01-01

    Storm Sandy first appeared as a tropical storm in the southern Caribbean Sea on Oct. 22, 2012, moved northeastward, turned northwestward, and made landfall near Brigantine, New Jersey in late October. Sandy devastated surrounding areas, caused an estimated damage of $50 billion, and became the second costliest tropical cyclone (TC) in U.S. History surpassed only by Hurricane Katrina (2005). To save lives and mitigate economic damage, a central question to be addressed is to what extent the lead time of severe storm prediction such as Sandy can be extended (e.g., Emanuel 2012; Kerr 2012). In this study, we present 10 numerical experiments initialized at 00 and 1200 UTC Oct. 22-26, 2012, with the NASA coupled advanced global modeling and visualization systems (CAMVis). All of the predictions realistically capture Sandy's movement with the northwestward turn prior to its landfall. However, three experiments (initialized at 0000 UTC Oct. 22 and 24 and 1200 UTC Oct. 22) produce larger errors. Among the 10 experiments, the control run initialized at 0000 UTC Oct. 23 produces a remarkable 7-day forecast. To illustrate the impact of environmental flows on the predictability of Sandy, we produce and discuss four-dimensional (4-D) visualizations with the control run. 4-D visualizations clearly demonstrate the following multiscale processes that led to the sinuous track of Sandy: the initial steering impact of an upper-level trough (appearing over the northwestern Caribbean Sea and Gulf of Mexico), the blocking impact of systems to the northeast of Sandy, and the binary interaction with a mid-latitude, upper-level trough that appeared at 130degrees west longitude on Oct. 23, moved to the East Coast and intensified during the period of Oct. 29-30 prior to Sandy's landfall.

  11. Influence of advective bio-irrigation on carbon and nitrogen cycling in sandy sediments

    OpenAIRE

    Na, T.; Gribsholt, B.; Galaktionov, O. S.; T. Lee; Meysman, F. J. R.

    2008-01-01

    In sandy sediments, the burrow ventilation activity of benthic macrofauna can generate substantial advective flows within the sediment surrounding their burrows. Here we investigated the effects of such advective bio-irrigation on carbon and nitrogen cycling in sandy sediments. To this end, we combined a range of complementary experimental and modelling approaches in a microcosm study of the lugworm Arenicola marina (Polychaeta: Annelida). Bio-irrigation rates were determined using uranine as...

  12. Utilization of Geotextile Tube for Sandy and Muddy Coastal Management: A Review

    OpenAIRE

    Siew Cheng Lee; Roslan Hashim; Shervin Motamedi; Ki-Il Song

    2014-01-01

    Threats to beaches have accelerated the coastal destruction. In recent decades, geotextile tubes were used around the world to prevent coastal erosion, to encourage beach nourishment, and to assist mangrove rehabilitation. However, the applications of geotextile tube in sandy and muddy coasts have different concerns as the geological settings are different. Applications of geotextile tubes in sandy beaches were mainly to prevent coastline from further erosion and to nourish the beach. However...

  13. Dissolved and Bubble Gas Concentrations in Sandy Surficial Sediments of the West Florida Sand Sheet

    Science.gov (United States)

    2016-06-21

    Dissolved and Bubble Gas Concentrations in Sandy Surficial Sediments of the West Florida Sand Sheet Christopher Martens Dept. of Marine Sciences CB...TITLE AND SUBTITLE Dissolved and Bubble Gas Concentrations in Sandy Surficial Sediments of the West Florida Sand Sheet 5a. CONTRACT NUMBER 5b. GRANT...was noted that there was substantially higher organic material in the shallow troughs of the sand ripples than on the crests. Most of this appears

  14. 33 CFR 165.130 - Sandy Hook Bay, New Jersey-security zone.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Sandy Hook Bay, New Jersey... Specific Regulated Navigation Areas and Limited Access Areas First Coast Guard District § 165.130 Sandy... following boundaries are a security zone: A line beginning on the shore at 40°25′55.6″ N, 074°04′31.4″ W...

  15. Tropical grasslands: A pivotal place for a more multi-functional agriculture.

    Science.gov (United States)

    Boval, Maryline; Angeon, Valérie; Rudel, Tom

    2017-02-01

    Tropical grasslands represent a pivotal arena for the sustainable intensification of agriculture in the coming decades. The abundant ecosystem services provided by the grasslands, coupled with the aversion to further forest destruction, makes sustainable intensification of tropical grasslands a high policy priority. In this article, we provide an inventory of agricultural initiatives that would contribute to the sustainable intensification of the tropical grassland agro-ecosystem, and we recommend a shift in the scientific priorities of animal scientists that would contribute to realization of a more agro-ecological and multi-functional agriculture in the world's tropical grasslands.

  16. Quasi 3D modelling of water flow in the sandy soil

    Science.gov (United States)

    Rezaei, Meisam; Seuntjens, Piet; Joris, Ingeborg; Boënne, Wesley; De Pue, Jan; Cornelis, Wim

    2016-04-01

    Monitoring and modeling tools may improve irrigation strategies in precision agriculture. Spatial interpolation is required for analyzing the effects of soil hydraulic parameters, soil layer thickness and groundwater level on irrigation management using hydrological models at field scale. We used non-invasive soil sensor, a crop growth (LINGRA-N) and a soil hydrological model (Hydrus-1D) to predict soil-water content fluctuations and crop yield in a heterogeneous sandy grassland soil under supplementary irrigation. In the first step, the sensitivity of the soil hydrological model to hydraulic parameters, water stress, crop yield and lower boundary conditions was assessed after integrating models at one soil column. Free drainage and incremental constant head conditions were implemented in a lower boundary sensitivity analysis. In the second step, to predict Ks over the whole field, the spatial distributions of Ks and its relationship between co-located soil ECa measured by a DUALEM-21S sensor were investigated. Measured groundwater levels and soil layer thickness were interpolated using ordinary point kriging (OK) to a 0.5 by 0.5 m in aim of digital elevation maps. In the third step, a quasi 3D modelling approach was conducted using interpolated data as input hydraulic parameter, geometric information and boundary conditions in the integrated model. In addition, three different irrigation scenarios namely current, no irrigation and optimized irrigations were carried out to find out the most efficient irrigation regime. In this approach, detailed field scale maps of soil water stress, water storage and crop yield were produced at each specific time interval to evaluate the best and most efficient distribution of water using standard gun sprinkler irrigation. The results show that the effect of the position of the groundwater level was dominant in soil-water content prediction and associated water stress. A time-dependent sensitivity analysis of the hydraulic

  17. Nonfatal injuries 1 week after hurricane sandy--New York city metropolitan area, October 2012.

    Science.gov (United States)

    Brackbill, Robert M; Caramanica, Kimberly; Maliniak, Maret; Stellman, Steven D; Fairclough, Monique A; Farfel, Mark R; Turner, Lennon; Maslow, Carey B; Moy, Amanda J; Wu, David; Yu, Shengchao; Welch, Alice E; Cone, James E; Walker, Deborah J

    2014-10-24

    On October 29, 2012, Hurricane Sandy (Sandy) made landfall in densely populated areas of New York, New Jersey, and Connecticut. Flooding affected 51 square miles (132 square kilometers) of New York City (NYC) and resulted in 43 deaths, many caused by drowning in the home, along with numerous storm-related injuries. Thousands of those affected were survivors of the World Trade Center (WTC) disaster of September 11, 2001 (9/11) who had previously enrolled in the WTC Health Registry (Registry) cohort study. To assess Sandy-related injuries and associated risk factors among those who lived in Hurricane Sandy-flooded areas and elsewhere, the NYC Department of Health and Mental Hygiene surveyed 8,870 WTC survivors, who had provided physical and mental health updates 8 to 16 months before Sandy. Approximately 10% of the respondents in flooded areas reported injuries in the first week after Sandy; nearly 75% of those had more than one injury. Injuries occurred during evacuation and clean-up/repair of damaged or destroyed homes. Hurricane preparation and precautionary messages emphasizing potential for injury hazards during both evacuation and clean-up or repair of damaged residences might help mitigate the occurrence and severity of injury after a hurricane.

  18. Investigation of superstorm Sandy 2012 in a multi-disciplinary approach

    Directory of Open Access Journals (Sweden)

    M. Kunz

    2013-10-01

    Full Text Available At the end of October 2012, Hurricane Sandy moved from the Caribbean Sea into the Atlantic Ocean and entered the United States not far from New York. Along its track, Sandy caused more than 200 fatalities and severe losses in Jamaica, The Bahamas, Haiti, Cuba, and the US. This paper demonstrates the capability and potential for near-real-time analysis of catastrophes. It is shown that the impact of Sandy was driven by the superposition of different extremes (high wind speeds, storm surge, heavy precipitation and by cascading effects. In particular the interaction between Sandy and an extra-tropical weather system created a huge storm that affected large areas in the US. It is examined how Sandy compares to historic hurricane events, both from a hydro-meteorological and impact perspective. The distribution of losses to different sectors of the economy is calculated with simple input-output models as well as government estimates. Direct economic losses are estimated about USD 4.2 billion in the Caribbean and between USD 78 and 97 billion in the US. Indirect economic losses from power outages is estimated in the order of USD 16.3 billion. Modelling sector-specific dependencies quantifies total business interruption losses between USD 10.8 and 15.5 billion. Thus, seven years after the record impact of Hurricane Katrina in 2005, Hurricane Sandy is the second costliest hurricane in the history of the United States.

  19. Hurricane Sandy Exposure and the Mental Health of World Trade Center Responders.

    Science.gov (United States)

    Bromet, Evelyn J; Clouston, Sean; Gonzalez, Adam; Kotov, Roman; Guerrera, Kathryn M; Luft, Benjamin J

    2017-04-03

    The psychological consequences of a second disaster on populations exposed to an earlier disaster have rarely been studied prospectively. Using a pre- and postdesign, we examined the effects of Hurricane Sandy on possible World Trade Center (WTC) related posttraumatic stress disorder (PTSD Checklist score of ≥ 50) and overall depression (major depressive disorder [MDD]; Patient Health Questionnaire depression score of ≥ 10) among 870 WTC responders with a follow-up monitoring visit at the Long Island WTC Health Program during the 6 months post-Hurricane Sandy. The Hurricane Sandy exposures evaluated were damage to home (8.3%) and to possessions (7.8%), gasoline shortage (24.1%), prolonged power outage (42.7%), and filing a Federal Emergency Management Agency claim (11.3%). A composite exposure score also was constructed. In unadjusted analyses, Hurricane Sandy exposures were associated with 1.77 to 5.38 increased likelihood of PTSD and 1.58 to 4.13 likelihood of MDD; odds ratios for ≥ 3 exposures were 6.47 for PTSD and 6.45 for MDD. After adjusting for demographic characteristics, WTC exposure, pre-Hurricane Sandy mental health status, and time between assessments, reporting ≥ 3 Hurricane Sandy exposures was associated with a 3.29 and 3.71 increased likelihood of PTSD and MDD, respectively. These findings underscore the importance of assessing the impact of a subsequent disaster in ongoing responder health surveillance programs.

  20. Evaluation of power outages in Connecticut during hypothetical future Hurricane Sandy scenarios

    Science.gov (United States)

    Wanik, D. W.; Anagnostou, E. N.; Astitha, M.; Frediani, M. E.; Yang, J.

    2015-12-01

    Reliable electric power is a staple of our modern society.The purpose of this work was to evaluate the occurrence of power outages under more intense, future Hurricane Sandy simulations in Connecticut. In addition, we also evaluated how many crews would be necessary to restore power in 7 days, and how different vegetation scenarios might contribute to a decrease in outages. We trained five pairwise models on each current Sandy runs (2012) as training using the random forest model (each validated using 10-fold cross-validation), and used each future Sandy run as an independent test. We predict that a future Sandy would have 2.5x as many outages as current Sandy, which would require 3.23x as many crews as current Sandy to restore power in 7 days. We also found that increased vegetation management might decrease outages, which has implications for both fair-weather and storm days of all types (i.e. blizzards, thunderstorms, ice storms). Although we have only evaluated outages for electric distribution networks, there are many other types (water supply, wastewater, telecommunications) that would likely benefit from an analysis of this type. In addition, given that we have the weather simulations already processed within our 2-km weather simulation domain, we would like to expand our vulnerability analyses to surrounding utilities in New Jersey, New York, Rhode Island, Massachusetts and New Hampshire to facilitate regional coordination among electric distribution networks.

  1. Investigation of superstorm Sandy 2012 in a multi-disciplinary approach

    Science.gov (United States)

    Kunz, M.; Mühr, B.; Kunz-Plapp, T.; Daniell, J. E.; Khazai, B.; Wenzel, F.; Vannieuwenhuyse, M.; Comes, T.; Elmer, F.; Schröter, K.; Fohringer, J.; Münzberg, T.; Lucas, C.; Zschau, J.

    2013-10-01

    At the end of October 2012, Hurricane Sandy moved from the Caribbean Sea into the Atlantic Ocean and entered the United States not far from New York. Along its track, Sandy caused more than 200 fatalities and severe losses in Jamaica, The Bahamas, Haiti, Cuba, and the US. This paper demonstrates the capability and potential for near-real-time analysis of catastrophes. It is shown that the impact of Sandy was driven by the superposition of different extremes (high wind speeds, storm surge, heavy precipitation) and by cascading effects. In particular the interaction between Sandy and an extra-tropical weather system created a huge storm that affected large areas in the US. It is examined how Sandy compares to historic hurricane events, both from a hydro-meteorological and impact perspective. The distribution of losses to different sectors of the economy is calculated with simple input-output models as well as government estimates. Direct economic losses are estimated about USD 4.2 billion in the Caribbean and between USD 78 and 97 billion in the US. Indirect economic losses from power outages is estimated in the order of USD 16.3 billion. Modelling sector-specific dependencies quantifies total business interruption losses between USD 10.8 and 15.5 billion. Thus, seven years after the record impact of Hurricane Katrina in 2005, Hurricane Sandy is the second costliest hurricane in the history of the United States.

  2. Hurricane Sandy (New Jersey): Mortality Rates in the Following Month and Quarter.

    Science.gov (United States)

    Kim, Soyeon; Kulkarni, Prathit A; Rajan, Mangala; Thomas, Pauline; Tsai, Stella; Tan, Christina; Davidow, Amy

    2017-08-01

    To describe changes in mortality after Hurricane Sandy made landfall in New Jersey on October 29, 2012. We used electronic death records to describe changes in all-cause and cause-specific mortality overall, in persons aged 76 years or older, and by 3 Sandy impact levels for the month and quarter following Hurricane Sandy compared with the same periods in earlier years adjusted for trends. All-cause mortality increased 6% (95% confidence interval [CI] = 2%, 11%) for the month, 5%, 8%, and 12% by increasing Sandy impact level; and 7% (95% CI = 5%, 10%) for the quarter, 5%, 8%, and 15% by increasing Sandy impact level. In elderly persons, all-cause mortality rates increased 10% (95% CI = 5%, 15%) and 13% (95% CI = 10%, 16%) in the month and quarter, respectively. Deaths that were cardiovascular disease-related increased by 6% in both periods, noninfectious respiratory disease-related by 24% in the quarter, infection-related by 20% in the quarter, and unintentional injury-related by 23% in the month. Mortality increased, heterogeneous by cause, for both periods after Hurricane Sandy, particularly in communities more severely affected and in the elderly, who may benefit from supportive services.

  3. EFFECTS OF ALKALINE SANDY LOAM ON SULFURIC SOIL ACIDITY AND SULFIDIC SOIL OXIDATION

    Directory of Open Access Journals (Sweden)

    Patrick S. Michael

    2015-08-01

    Full Text Available  In poor soils, addition of alkaline sandy loam containing an adequate proportion of sand, silt and clay would add value by improving the texture, structure and organic matter (OM for general use of the soils. In acid sulfate soils (ASS, addition of alkaline sandy would improve the texture and leach out salts as well as add a sufficient proportion of OM for vegetation establishment. In this study, addition of alkaline sandy loam into sulfuric soil effectively increased the pH, lowered the redox and reduced the sulfate content, the magnitude of the effects dependent on moisture content. Addition of alkaline sandy loam in combination with OM was highly effective than the effects of the lone alkaline sandy loam. When alkaline sandy was added alone or in combination with OM into sulfidic soil, the effects on pH and the redox were similar as in the sulfuric soil but the effect on sulfate content was variable. The effects under aerobic conditions were higher than under anaerobic conditions. The findings of this study have important implications for the general management of ASS where lime availability is a concern and its application is limited.International Journal of Environment Volume-4, Issue-3, June-August 2015Page: 42-54

  4. IMPROVEMENT OF SANDY SOIL WITH WATER-CONSERVING MEMBRANE AND ITS EFFECT ON CROP GROWTH

    Institute of Scientific and Technical Information of China (English)

    LI Xiu-jun; CUI Xiang-hao; LI Qu-sheng

    2005-01-01

    Water-conserving membrane is a new material of improving sandy soil. It is based on the rule that a compound with organic and inorganic components can produce colloid after its integrating with Ca2+ in soil. The water-conserving membrane will obstruct capillary and increase viscidity of sandy soil, so as to decrease leakage and evaporation in sandy soil. The water-conserving membrane contains polyacrylic acid (PAA) and bentonite. When PAA concentration and Ph of solution are different, water-conserving membrane can be made in different depth of soil. This experiment shows that the solution with 0.2% PAA does not harm and poison the crops, on the contrary,promotes crop germination. The solution with 0.2% or 0.4% PAA can accelerate corn growth. Accordingly, different crops need the application of the different PAA concentrations in the cultivation. Therefore, on the basis of different vadose coefficient in sandy soil, the solution with different PAA concentration can improve sandy soil and increase its water-conserving competence very well. The solution can be used to improve sandy soil and control desert enlargement in arid, semi-arid and semi-humid areas.

  5. The Vegetation of North-Western Mongolia: Floristic Checklist and Conservation Status of Mongolian Grassland Flora

    Directory of Open Access Journals (Sweden)

    Katharina Lapin

    2017-05-01

    Full Text Available Mongolia´s grassland (steppe is reported to be vulnerable to climate change, degradation, and densifi cation. The traditional Mongolian pastoral herding system is currently transforming due to changes in market relations and economic developments, and this transformation has an impact on species composition and biodiversity. For this study, we observed the current situation of the fl ora in the north-western Mongolian territories to provide data on plant species occurrence in this remote area. A vegetation assessment was conducted for 15 locations in June and July 2016. Indicator plant species were determined to assess the level of grazing and degradation, as well as the respective steppe sub-type. The conservation status of all recorded plant species was assessed in accordance with the IUCN Red List. In total, 106 vascular plant species belonging to 73 genera and 26 families were recorded. Four endemic plant species were observed. All locations were classifi ed into three steppe sub-types: Desert-steppe, dry-steppe and mountain-steppe. A large number of degradation indicator plant species were observed in almost all locations. No endangered species in the Mongolian IUCN Red List were observed. The observation indicates that the vegetation in the north-western area of Mongolia is partly showing tendencies towards overgrazing and degradation. The conservation status of the most recorded species is currently unknown, and more studies on Mongolian vegetation will need to be conducted to assess these species’ status. We emphasize the urgent need for further studies on the vegetation and plant species composition, and indicators in north-western Mongolia, especially in context of the ongoing rapid economic, social, and ecological changes in the region

  6. Land and Forest Degradation inside Protected Areas in Latin America

    Directory of Open Access Journals (Sweden)

    Louis Reymondin

    2013-11-01

    Full Text Available Using six years of remote sensing data, we estimated land and forest degradation inside 1788 protected areas across 19 countries in Latin America. From 2004–2009, the rate of land and forest degradation increased by 250% inside the protected areas, and the land and forest degradation totaled 1,097,618 hectares. Of the protected areas in our dataset, 45% had land and forest degradation. There were relatively large variations by major habitat type, with flooded grasslands/savannas and moist broadleaf forest protected areas having the highest rates of degradation. We found no association between a country’s rate of land and forest degradation inside protected areas and Gross Domestic Product (GDP per capita, GDP growth, or rural population density. We found significant, but weak, associations between the rate of land and forest degradation inside protected areas and a country’s protected area system funding, the size of the protected area, and one International Union for the Conservation of Nature (IUCN management category. Our results suggest a high degree of heterogeneity in the variables impacting land and forest degradation inside protected areas in Latin America, but that the targeting of protected area investments on a continental scale is plausible.

  7. Diets of greater prairie chickens on the Sheyenne National Grasslands

    Science.gov (United States)

    Mark A. Rumble; Jay A. Newell; John E. Toepfer

    1988-01-01

    Diets of greater prairie chickens on the Sheyenne National Grassland of North Dakota were examined. During the winter months agricultural crops (primarily corn) were the predominant food items. Green vegetation was consumed in greater quantities as spring progressed. Dandelion flowers and alfalfa/sweetclover were the major vegetative food items through the summer. Both...

  8. Ecological dynamic model of grassland and its practical verification

    Institute of Scientific and Technical Information of China (English)

    ZENG; Xiaodong

    2005-01-01

    Based on the physico-biophysical considerations, mathematical analysis and some approximate formulations generally adopted in meteorology and ecology, an ecological dynamic model of grassland is developed. The model consists of three interactive variables, I.e. The biomass of living grass, the biomass of wilted grass, and the soil wetness. The major biophysical processes are represented in parameterization formulas, and the model parameters can be determined inversely by using the observational climatological and ecological data. Some major parameters are adjusted by this method to fit the data (although incomplete) in the Inner Mongolia grassland, and other secondary parameters are estimated through sensitivity studies. The model results are well agreed with reality, e.g., (I) the maintenance of grassland requires a minimum amount of annual precipitation (approximately 300 mm); (ii) there is a significant relationship between the annual precipitation and the biomass of living grass; and (iii) the overgrazing will eventually result in desertification. A specific emphasis is put on the shading effect of the wilted grass accumulated on the soil surface. It effectively reduces the soil surface temperature and the evaporation, hence benefits the maintenance of grassland and the reduction of water loss in the soil.

  9. Potassium cycling and losses in grassland systems : a review

    NARCIS (Netherlands)

    Kayser, M; Isselstein, J

    Cycling of potassium in grassland systems has received relatively little attention in research and practice in recent years. Balanced nutrient systems require consideration of nutrients other than nitrogen (N). Potassium (K) is needed in large amounts and is closely related to N nutrition. In

  10. Effects of large herbivores on grassland arthropod diversity

    NARCIS (Netherlands)

    van Klink, R.; van der Plas, F.; van Noordwijk, C. G. E. (Toos); WallisDeVries, M. F.; Olff, H.

    Both arthropods and large grazing herbivores are important components and drivers of biodiversity in grassland ecosystems, but a synthesis of how arthropod diversity is affected by large herbivores has been largely missing. To fill this gap, we conducted a literature search, which yielded 141

  11. Appreciation of the functions of grasslands by European stakeholders

    NARCIS (Netherlands)

    Pol - Van Dasselaar, Van Den A.; Golinski, P.; Hennessy, D.; Huyghe, C.; Parente, G.; Peyraud, J.L.

    2014-01-01

    The European project MultiSward aimed to increase the reliance of farmers on grasslands and on multi-species swards for competitive and sustainable ruminant production systems. Active participation of stakeholders was one of the key objectives of the project. The aim of the current study was to get

  12. Regional dynamics of grassland change in the western Great Plains

    Science.gov (United States)

    Drummond, M.A.

    2007-01-01

    This paper examines the contemporary land-cover changes in two western Great Plains ecoregions between 1973 and 2000. Agriculture and other land uses can have a substantial effect on grassland cover that varies regionally depending on the primary driving forces of change. In order to better understand change, the rates, types, and causes of land conversion were examined for 1973, 1980, 1986, 1992, and 2000 using Landsat satellite data and a statistical sampling strategy. The overall estimated rate of land-cover change between 1973 and 2000 was 7.4% in the Northwestern Great Plains and 11.5% in the Western High Plains. Trends in both ecoregions have similarities, although the dynamics of change differ temporally depending on driving forces. Between 1973 and 1986, grassland cover declined when economic opportunity drove an expansion of agriculture. Between 1986 and 2000, grassland expanded as public policy and a combination of socioeconomic factors drove a conversion from agriculture to grassland. ?? 2007 Copyright by the Center for Great Plains Studies, University of Nebraska-Lincoln.

  13. Relative Greenness Index for assessing curing of grassland fuel

    NARCIS (Netherlands)

    Newnham, G.J.; Verbesselt, J.; Grant, I.F.; Anderson, S.A.J.

    2011-01-01

    Knowledge of the proportion of live and dead herbaceous fuel in grasslands is important in determining fire danger. This paper examines the Relative Greenness approach for quantifying these live and dead proportions. Relative Greenness places the Normalized Difference Vegetation Index (NDVI) in the

  14. Homogenization of the soil surface following fire in semiarid grasslands

    Science.gov (United States)

    Carleton S. White

    2011-01-01

    Semiarid grasslands accumulate soil beneath plant "islands" that are raised above bare interspaces. This fine-scale variation in microtopographic relief is plant-induced and is increased with shrub establishment. Research found that fire-induced water repellency enhanced local-scale soil erosion that reduced variation in microtopographic relief, suggesting...

  15. Controlling nitrous oxide emissions from grassland livestock production systems

    NARCIS (Netherlands)

    Oenema, O.; Gebauer, G.; Rodriguez, M.; Sapek, A.; Jarvis, S.C.; Corré, W.J.; Yamulki, S.

    1998-01-01

    There is growing awareness that grassland livestock production systems are major sources of nitrous oxide (N2O). Controlling these emissions requires a thorough understanding of all sources and controlling factors at the farm level. This paper examines the various controlling factors and proposes

  16. Bird Use of Grassland Habitat Patches at a Military Airfield

    Science.gov (United States)

    In light of reported declines in grassland bird populations in North America, information about their use of airfield habitats can help inform management decisions in the context of conflicting objectives of minimizing wildlife-aircraft collisions and helping to conserve grasslan...

  17. Bird Use of Grassland Habitat Patches at a Military Airfield

    Science.gov (United States)

    In light of reported declines in grassland bird populations in North America, information about their use of airfield habitats can help inform management decisions in the context of conflicting objectives of minimizing wildlife-aircraft collisions and helping to conserve grasslan...

  18. Fine-scale species associations in alvar limestone grasslands

    NARCIS (Netherlands)

    Diekmann, M; Dupre, C; van der Maarel, E

    2004-01-01

    To examine the importance of positive or negative interactions of plant species on a micro-scale, species associations were studied in 38 1 m(2) - plots in alvar limestone grasslands on Oland, Sweden. Each plot was assumed to be homogeneous as to its environmental conditions and spatial distribution

  19. Priming of soil carbon decomposition in two Inner Mongolia grassland soils following sheep dung addition: a study using ¹³C natural abundance approach.

    Directory of Open Access Journals (Sweden)

    Xiuzhi Ma

    Full Text Available To investigate the effect of sheep dung on soil carbon (C sequestration, a 152 days incubation experiment was conducted with soils from two different Inner Mongolian grasslands, i.e. a Leymus chinensis dominated grassland representing the climax community (2.1% organic matter content and a heavily degraded Artemisia frigida dominated community (1.3% organic matter content. Dung was collected from sheep either fed on L. chinensis (C3 plant with δ¹³C = -26.8‰; dung δ¹³C = -26.2‰ or Cleistogenes squarrosa (C₄ plant with δ¹³C = -14.6‰; dung δ¹³C = -15.7‰. Fresh C₃ and C₄ sheep dung was mixed with the two grassland soils and incubated under controlled conditions for analysis of ¹³C-CO₂ emissions. Soil samples were taken at days 17, 43, 86, 127 and 152 after sheep dung addition to detect the δ¹³C signal in soil and dung components. Analysis revealed that 16.9% and 16.6% of the sheep dung C had decomposed, of which 3.5% and 2.8% was sequestrated in the soils of L. chinensis and A. frigida grasslands, respectively, while the remaining decomposed sheep dung was emitted as CO₂. The cumulative amounts of C respired from dung treated soils during 152 days were 7-8 times higher than in the un-amended controls. In both grassland soils, ca. 60% of the evolved CO₂ originated from the decomposing sheep dung and 40% from the native soil C. Priming effects of soil C decomposition were observed in both soils, i.e. 1.4 g and 1.6 g additional soil C kg⁻¹ dry soil had been emitted as CO₂ for the L. chinensis and A. frigida soils, respectively. Hence, the net C losses from L. chinensis and A. frigida soils were 0.6 g and 0.9 g C kg⁻¹ soil, which was 2.6% and 7.0% of the total C in L. chinensis and A. frigida grasslands soils, respectively. Our results suggest that grazing of degraded Inner Mongolian pastures may cause a net soil C loss due to the positive priming effect, thereby accelerating soil

  20. Legacy effects of grassland management on soil carbon to depth.

    Science.gov (United States)

    Ward, Susan E; Smart, Simon M; Quirk, Helen; Tallowin, Jerry R B; Mortimer, Simon R; Shiel, Robert S; Wilby, Andrew; Bardgett, Richard D

    2016-08-01

    The importance of managing land to optimize carbon sequestration for climate change mitigation is widely recognized, with grasslands being identified as having the potential to sequester additional carbon. However, most soil carbon inventories only consider surface soils, and most large-scale surveys group ecosystems into broad habitats without considering management intensity. Consequently, little is known about the quantity of deep soil carbon and its sensitivity to management. From a nationwide survey of grassland soils to 1 m depth, we show that carbon in grassland soils is vulnerable to management and that these management effects can be detected to considerable depth down the soil profile, albeit at decreasing significance with depth. Carbon concentrations in soil decreased as management intensity increased, but greatest soil carbon stocks (accounting for bulk density differences), were at intermediate levels of management. Our study also highlights the considerable amounts of carbon in subsurface soil below 30 cm, which is missed by standard carbon inventories. We estimate grassland soil carbon in Great Britain to be 2097 Tg C to a depth of 1 m, with ~60% of this carbon being below 30 cm. Total stocks of soil carbon (t ha(-1) ) to 1 m depth were 10.7% greater at intermediate relative to intensive management, which equates to 10.1 t ha(-1) in surface soils (0-30 cm), and 13.7 t ha(-1) in soils from 30 to 100 cm depth. Our findings highlight the existence of substantial carbon stocks at depth in grassland soils that are sensitive to management. This is of high relevance globally, given the extent of land cover and large stocks of carbon held in temperate managed grasslands. Our findings have implications for the future management of grasslands for carbon storage and climate mitigation, and for global carbon models which do not currently account for changes in soil carbon to depth with management.