Using GIS tools to detect the land use/land cover changes during forty years in Lodhran District of Pakistan

Environmental Science and Pollution Research - Land use/land cover (LULC) change has serious implications for environment as LULC is directly related to land degradation over a period of time and...     

Combating land degradation through participatory means: the case of Swaziland

This paper examines a community grazing project to rehabilitate degraded land in Swaziland. Using data from interviews, questionnaires, and focus groups, we show that the ways in which participatory, decentralized approaches to natural resource management play out at the local level are closely linked to national-level power structures. The successes and issues that emerge at different stages of the grazing project reflect local socioeconomic priorities and show how people manage their time and labor according to household livelihood goals. However, the project favored the interests of cattle owners who were already the more socially and politically powerful members of the community. We argue that for participatory natural resource management to be more meaningful to communities, projects should focus on local ecological priorities, rather than addressing the environmental concerns that are rooted within existing dominant power structures. This requires change to social and political relationships across levels and the building of new institutions.     

An autonomous aerosol sampler/elemental analyzer designed for ocean buoys and remote land sites

An autonomous aerosol sampler/elemental analyzer, that employs energy dispersive X-ray fluorescence spectrometry to determine the elemental (Fe, Si, S, Ca and K) concentrations of aerosols in near real time, has been designed, built and successfully tested on a roof. The ultimate technical goal is to deploy a buoy-mounted aerosol sampler/analyzer in order to make the long-term measurements necessary to quantify the deposition of mineral dust to the oceans. A major scientific goal is to address the question of enhanced biological production due to the release of dissolved iron from the deposition of mineral dust. Design and operating features are discussed and illustrated. This instrument has the sensitivity to measure the concentrations of mineral dust and Fe over the oceans with a time resolution of a few days during periods of moderate to high dust deposition.     

A functional perspective on the analysis of land use and land cover data in ecology

Assessments of large-scale changes in habitat are a priority for management and conservation. Traditional approaches use land use and land cover data (LULC) that focus mostly on “structural” properties of landscapes, rather than “functional” properties related to specific ecological processes. Here, we contend that designing functional analyses of LULC can provide important and complementary information to traditional, structural analyses. We substantiate this perspective with an example of functional changes in habitat due to industrial anthropogenic footprints in Alberta’s boreal forest, where there has been little overall forest loss (~ 6% structural change), but high levels of functional change (up to 93% functional change) for species’ habitat, biodiversity, and wildfire ignition. We discuss the methods needed to achieve functional LULC analyses, when they are most appropriate to add to structural assessments, and conclude by providing recommendations for analyses of LULC in a future of increasingly high-resolution, dynamic remote sensing data.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01434-5) contains supplementary material, which is available to authorized users.     

Scale-dependence of land use effects on water quality of streams in agricultural catchments

The influence of land use on water quality in streams is scale-dependent and varies in time and space. In this study, land cover patterns and stocking rates were used as measures of agricultural development in two pasture and one native grassland catchment in New Zealand and were related to water quality in streams of various orders. The amount of pasture per subcatchment correlated well to total nitrogen and nitrate in one catchment and turbidity and total phosphorous in the other catchment. Stocking rates were only correlated to total phosphorous in one pasture catchment but showed stronger correlations to ammonium, total phosphorous and total nitrogen in the other pasture catchment. Winter and spring floods were significant sources of nutrients and faecal coliforms from one of the pasture catchments into a wetland complex. Nutrient and faecal coliform concentrations were better predicted by pastural land cover in fourth-order than in second-order streams. This suggests that upstream land use is more influential in larger streams, while local land use and other factors may be more important in smaller streams. These temporal and spatial scale effects indicate that water-monitoring schemes need to be scale-sensitive.     

Numerical simulation of an array of fences in Saemangeum reclaimed land

This paper discusses about the quantitative effect of windbreak fences on wind velocity in the reclaimed land at Saemangeum in South Korea. Windbreak fences were constructed in the reclaimed land to reduce the wind velocity to prevent the generation and diffusion of dust. However, up to this time, no in-depth studies were conducted to quantitatively measure the effect of the windbreak fences on wind velocity thus an optimum windbreak structure is not yet determined. Using CFD simulations, the effects of fence porosity, fence height, and the distance between the adjacent fences were investigated. A wind tunnel experiment was initially conducted and data gathered were used to develop the CFD models. From the experiments and CFD simulations, the overall percentage difference of the measured velocities was 7.20% which is generally acceptable to establishing the reliability of the CFD models. The reduction effect on wind velocity was measured in between the adjacent fences up to a height of 0.6 m from the ground surface. In terms of porosity ( = 0, 0.2, 0.4, 0.6), 0.2 was found to be the optimum value. Conversely, the effect of fence height (0.6, 0.8 and 1.0 m) showed no significant difference; therefore, 0.6 m height is recommended. In addition, the reduction effect of distance between the adjacent fences (2, 4 and 6 m) on wind velocity having a 0.2 porosity has decreased to about 75% regardless of the distance. In the case of the reclaimed land in Saemangeum, a decrease of 75% can prevent the generation and diffusion of dusts. However, the source of dusts is very large. Therefore, constructing an array of windbreak with 6 m distance between them is deemed necessary.     

Survival of Escherichia coli O157:H7 in soils under different land use types

Laboratory studies on Escherichia coli O157:H7 survival in soils from four different land use types: forest, tea plantation, bamboo grove, and vegetable garden were investigated at 25?±?1 °C with the field capacity (soil water content at ?33 kPa). Results showed that E. coli O157:H7 declined quickly in the test soils, but its survival dynamics varied in the soils under different land use types. The survival time needed to reach the detection limit (t _d) in the test soils ranged from 2.1 to 3.6 days, with slightly longer t _d values being observed in soils from the bamboo grove. Stepwise multiple regression analysis revealed that the t _d values were shorter in sandy, lower pH, and lower organic carbon content soils. Different E. coli O157:H7 survival time in the soils under different land uses suggests that it is important to adapt proper management practices for reducing the potential risks of pathogen contamination when diary manure is applied to agricultural land.     

Enhanced phytoremediation of arsenic contaminated land

In an attempt to clean up arsenic (As) contaminated soil, the effects of phosphorus (P) fertilizer and rhizosphere microbes on arsenic accumulation by the silverback fern, Pityrogramma calomelanos, were investigated in both greenhouse and field experiments. Field experiments were conducted in Ron Phibun District, an As-contaminated area in Thailand. Soil (136-269 microg As g(-1)) was collected there and used in the greenhouse experiment. Rhizosphere microbes (bacteria and fungi) were isolated from roots of P. calomelanos growing in Ron Phibun District. The results showed that P-fertilizer significantly increased plant biomass and As accumulation of the experimental P. calomelanos. Rhizobacteria increased significantly the biomass and As content of the test plants. Thus, P-fertilizer and rhizosphere bacteria enhanced As-phytoextraction. In contrast, rhizofungi reduced significantly As concentration in plants but increased plant biomass. Therefore, rhizosphere fungi exerted their effects on phytostabilization.     

Study of evolution of PCDD/F in sewage sludge-amended soils for land restoration purposes

The evolution of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) in sewage sludge-amended soils used in the restoration of degraded lands, like quarries, has been studied. Two experiments were performed: one in the lab, under controlled conditions, and another in a quarry. Two different doses of sewage sludge were applied in both experiments (with two types of application in the quarry experiment) and the evolution of the amended soils were compared with that of the respective control soils (without addition of sewage sludge). The samples were analyzed with a previously validated method by HRGC HRMS after the extraction and the necessary clean-up steps. The results reveal that polluted sewage sludge increases PCDD/F concentration in soils and that these compounds are persistent in the matrix after long periods of time.     

Future land use and land cover influences on regional biogenic emissions and air quality in the United States

A regional modeling system was applied with inputs from global climate and chemistry models to quantify the effects of global change on future biogenic emissions and their impacts on ozone and biogenic secondary organic aerosols (BSOA) in the US. Biogenic emissions in the future are influenced by projected changes in global and regional climates and by variations in future land use and land cover (LULC). The modeling system was applied for five summer months for the present-day case (1990–1999, Case 1) and three future cases covering 2045–2054. Individual future cases were: present-day LULC (Case 2); projected-future LULC (Case 3); and future LULC with designated regions of tree planting for carbon sequestration (Case 4). Results showed changing future meteorology with present-day LULC (Case 2) increased average isoprene and monoterpene emission rates by 26% and 20% due to higher temperature and solar insolation. However when LULC was changed together with climate (Case 3), predicted isoprene and monoterpene emissions decreased by 52% and 31%, respectively, due primarily to projected cropland expansion. The reduction was less, at 31% and 14% respectively, when future LULC changes were accompanied by regions of tree planting (Case 4). Despite the large decrease in biogenic emission, future average daily maximum 8-h (DM8H) ozone was found to increase between +8 ppbv and +10 ppbv due to high future anthropogenic emissions and global chemistry conditions. Among the future cases, changing LULC resulted in spatially varying future ozone differences of ?5 ppbv to +5 ppbv when compared with present-day case. Future BSOA changed directly with the estimated monoterpene emissions. BSOA increased by 8% with current LULC (Case 2) but decreased by 45%–28% due to future LULC changes. Overall, the results demonstrated that on a regional basis, changes in LULC can offset temperature driven increases in biogenic emissions, and, thus, LULC projection is an important factor to consider in the study of future regional air quality.     

Woody biomass phytoremediation of contaminated brownfield land

Economic and environmental regeneration of post-industrial landscapes frequently involves some element of re-afforestation or tree planting. We report field trials that evaluate whether woody biomass production is compatible with managing residual trace element contamination in brownfield soils. Large-scale mapping of contamination showed a heterogenous dispersion of metals and arsenic, and highly localised within-site hotspots. Yields of Salix, Populus and Alnus were economically viable, showing that short-rotation coppice has a potentially valuable role in community forestry. Mass balance modelling demonstrated that phytoextraction potentially could reduce contamination hotspots of more mobile elements (Cd and Zn) within a 25-30-year life cycle of the crops. Cd and Zn in stems and foliage of Salix were 4-13 times higher than EDTA-extractable soil concentrations. Lability of other trace elements (As, Pb, Cu, Ni) was not increased 3 years after planting the coppice; woody biomass may provide an effective reduction of exposure (phyto-stabilization) to these less mobile contaminants.     

Biogenic nitric oxide from wastewater land application

The importance of municipal wastewater land application to nitric oxide production and transport in soil was studied through the formulation and conduct of a comprehensive laboratory testing protocol. Nitric oxide (NO) is a precursor in the formation of tropospheric ozone which can directly impact public health and the environment. It is the uncertainty in the NO budget, and its relation to O₃, that motivates the need for measurements and modeling of NO flux from soils. Wastewater-amended soil is potentially one important component of that budget. NO emissions reported here were measured from: a well-characterized unamended soil, water-amended soil, and wastewater-amended soil in the laboratory in a dynamic test chamber. Laboratory results indicate that NO emissions from the selected sandy loam soil ranged from 0.3 to 0.4 ng N m^-2 s^-1 per cm² of unamended soil, while water-amended soil emissions ranged from 0.4 to 0.7 ng N m^-2 s^-1 per cm². NO flux from wastewater-amended soil ranged from 1.0 to 1.2 ng N m^-2 s^-1 per cm² of applied soil.     

Intrinsic and induced isoproturon catabolic activity in dissimilar soils and soils under dissimilar land use

The catabolic activity with respect to the systemic herbicide isoproturon was determined in soil samples by (14)C-radiorespirometry. The first experiment assessed levels of intrinsic catabolic activity in soil samples that represented three dissimilar soil series under arable cultivation. Results showed average extents of isoproturon mineralisation (after 240 h assay time) in the three soil series to be low. A second experiment assessed the impact of addition of isoproturon (0.05 microg kg(-1)) into these soils on the levels of catabolic activity following 28 days of incubation. Increased catabolic activity was observed in all three soils. A third experiment assessed levels of intrinsic catabolic activity in soil samples representing a single soil series managed under either conventional agricultural practice (including the use of isoproturon) or organic farming practice (with no use of isoproturon). Results showed higher (and more consistent) levels of isoproturon mineralisation in the soil samples collected from conventional land use. The final experiment assessed the impact of isoproturon addition on the levels of inducible catabolic activity in these soils. The results showed no significant difference in the case of the conventional farm soil samples while the induction of catabolic activity in the organic farm soil samples was significant.     

The impact of using different land cover data on wind-blown desert dust modeling results in the southwestern United States

Olson World Ecosystem (OWE) land cover data based on data sources of the 1970s and 1980s with a 10-min spatial resolution, and up-to-date Moderate Resolution Imaging Spectroradiometer (MODIS) land cover data with a 30-s resolution, were used, respectively, in modeling wind-blown desert dust in the southwest United States. The model using different land cover data sets preformed similarly in modeling meteorological field patterns, vertical profiles and surface wind and temperature, in comparisons against observations. The differences of wind and temperature at a specific time and location can be big. Compared against satellite and ground measurements, modeled dust spatial distributions using MODIS land cover data were considerably better than those using OWE land cover. Site against site comparisons of modeled and observed surface PM2.5 concentration time series showed that model performance improved significantly using MODIS land cover data. Modeled surface PM2.5 contour distributions using MODIS land cover data compared more favorably against observations. The performance statistics for modeled PM2.5 concentrations at 40 surface sites increased from 0.15 using OWE data, to 0.58 using MODIS data. This demonstrates that the survey updates and spatial resolution of land cover data are critical in correctly predicting dust events and dust concentrations. Using land cover data such as MODIS data from satellite remote sensing is promising in improving wind-blown dust modeling and forecasting.     

Transport of veterinary antibiotics in overland flow following the application of slurry to arable land

The environment may be exposed to veterinary medicines administered to livestock due to the application of organic fertilisers to land. Slurry is often spread on to fields following the harvest of the previous crop. Despite recommendations to do so, the slurry may not be ploughed into the soil for some time. If precipitation occurs before incorporation then it is likely that the slurry and any antibiotic residues in the slurry will be transported towards surface waters in overland flow. This phenomenon has been investigated in a plot study and transport via 'tramlines' has been compared to that through crop stubble. Three veterinary antibiotics, from the tetracycline, sulphonamide and macrolide groups, were applied to the plots in pig slurry. Twenty four hours after the application the plots were irrigated. Following this the plots received natural rainfall. Sulphachloropyridazine was detected in runoff from the tramline plot at a peak concentration of 703.2 microgl(-1) and oxytetracycline at 71.7 microgl(-1). Peak concentrations from the plot that did not contain a tramline were lower at 415.5 and 32 microgl(-1), respectively. In contrast, tylosin was not detected at all. Mass losses of the compounds were also greater from the tramline plot due to greater runoff generation. These did not exceed 0.42% for sulphachloropyridazine and 0.07% for oxytetracycline however.     

Influence of land use and land cover on the spatial variability of dissolved organic matter in multiple aquatic environments

Environmental Science and Pollution Research - Water quality of lakes, estuaries, and coastal areas serves as an indicator of the overall health of aquatic ecosystems as well as the health of the...     

Nocturnal boundary layer characteristics and land breeze development in Houston,Texas during TexAQS II

The nocturnal boundary layer in Houston, Texas was studied using a high temporal and vertical resolution tethersonde system on four nights during the Texas Air Quality Study II (TexAQS II) in August and September 2006. The launch site was on the University of Houston campus located approximately 4 km from downtown Houston. Of particular interest was the evolution of the nocturnal surface inversion and the wind flows within the boundary layer. The land–sea breeze oscillation in Houston has important implications for air quality as the cycle can impact ozone concentrations through pollutant advection and recirculation. The results showed that a weakly stable surface inversion averaging in depth between 145 and 200 m AGL formed on each of the experiment nights, typically within 2–3 h after sunset. Tethersonde vertical winds were compared with two other Houston data sets (High Resolution Doppler Lidar and radar wind profiler) from locations near the coastline and good agreement was found, albeit with a temporal lag at the tethersonde site. This comparison revealed development of a land breeze on three nights which began near the coastline and propagated inland both horizontally and vertically with time. The vertical temperature structure was significantly modified on one night at the tethersonde site after the land breeze wind shift, exhibiting near-adiabatic profiles below 100 m AGL.     

Possibilities for reducing nitrate leaching from agricultural land

Agricultural soil is a contributor of nitrate to natural waters. High nitrate levels in water leached from soils are related to high nitrate concentrations in drinking water, and excess levels change the ecological balance of rivers and lakes. In this paper, sound solutions to the major environmental issue of limiting nitrate leaching by modifying agricultural practices are discussed. The causes of nitrate leaching from agricultural land are briefly explained and existing measures for the reduction of nitrate losses are described, analyzed and evaluated. Reduction of nutrient leaching is not a question of organic or conventional farming, but rather of the introduction and use of appropriate countermeasures. We propose the following guiding principles to minimize leaching from agricultural soils. To some extent these principles require a new way of thinking: i) environmental indexing of fields and consideration of spatial variability within fields in relation to their contribution to leaching losses within a catchment; ii) reduction of nitrogen inputs to soil to levels slightly below those expected to give the optimum yield by applying less nitrogen fertilizer and by a further reduction in animal density; and iii) use of a range of counter-measures (catch crops, minimum tillage, control of biological processes, etc.) depending on how sensitive the farming system, soil and climate are to the risk of nitrate leaching.