A Conceptual Model for Defining and Assessing Land Management Units Using a Fuzzy Modeling Approach in GIS Environment

Appropriate land management decisions are important for current and future use of the land to ensure its sustainability. This requires that land management units (LMUs) be specified to enable the identification of specific parameters employed in decision making processes. This paper presents the development of a conceptual model, within geographic information systems (GIS), for defining and assessing LMUs from available biophysical information. The model consists of two main components (sub-models): land quality-based suitability analysis and soil erosion estimation. Using a fuzzy set methodology, the first sub-model was constructed to derive a land suitability index (LSI) for a cropping land utilization type. The LSI thus highlights the suitability grades of every pixel in the study area on a continuous basis. A sub-model of soil erosion was established based on the Revised Universal Soil Loss Equation (RUSLE) utilising the same spatial data bases employed for structuring the LSI. Using a soil loss tolerance principle, a fuzzy membership function of average annual soil loss (called soil loss index, SLI) was established, leading to compatibility between LSI and SLI for data integration. LMUs were then derived from various combinations of LSI and SLI. The methodology developed shows the significance of the model for refining available land suitability evaluation systems, which take no account of expected land degradation (from erosion) due to a nominated land use. It also provides a valuable guideline for cost-effective GIS applications in the identification and assessment of homogeneous land units, using available spatial information sets, at a finer scale.     

2000-2009年鄂南丘陵山区耕地集约利用变化分析

耕地集约利用是可持续发展的必然要求.从耕地集约利用内涵入手,通过构建耕地利用集约度的评价指标体系,采用主成分分析法对鄂南丘陵山区2000-2009年耕地集约利用进行了评价,并对耕地集约利用变化原因进行了分析.结果表明,10年间鄂南丘陵耕地的集约利用程度呈波动上升的趋势.目前阻碍鄂南丘陵山区耕地集约利用的因素主要为农田水利投入不足,占用耕地严重等,因此应加强耕地保护力度,积极进行耕地整治,加强水利基础设施建设,建立耕地环境质量安全体系.     

Spatial scaling between leaf area index maps of different resolutions

We developed algorithms for spatial scaling of leaf area index (LAI) using sub-pixel information. The study area is located near Liping County, Guizhou Province, in China. Methods for LAI spatial scaling were investigated on LAI images with 960 m resolution derived in two ways. LAI from distributed calculation (LAID) was derived using Landsat ETM+ data (30 m), and LAI from lumped calculation (LAIL) was obtained from the coarse (960 m) resolution data derived through resampling the ETM+ data. We found that lumped calculations can be considerably biased compared to the distributed (ETM+) case, suggesting that global and regional LAI maps can be biased if surface heterogeneity within the mapping resolution is ignored. Based on these results, we developed algorithms for removing the biases in lumped LAI maps using sub-pixel land cover-type information, and applied these to correct one coarse resolution LAI product which greatly improved its accuracy.     

安徽省城市用地扩张及城市化特征研究

根据安徽省1991-2005年城市建成区的扩展情况，从城市空间扩展动态度来对安徽省17个地级市进行城市扩展分类，由此得到城市空间扩展不同梯度的扩展类型。结合社会经济统计数据对安徽城市化特征进行分析，发现安徽省城市化取得了显著的成就，并在此基础上提出了面临的挑战，为城市化进程及城市土地资源的可持续发展提供科学依据。     

Effect of the Spatial Variability of Land Use,Soil Type,and Precipitation on Streamflows in Small Watersheds1

Abstract: The spatial variability of the data used in models includes the spatial discretization of the system into subsystems, the data resolution, and the spatial distribution of hydrologic features and parameters. In this study, we investigate the effect of the spatial distribution of land use, soil type, and precipitation on the simulated flows at the outlet of “small watersheds” (i.e., watersheds with times of concentration shorter than the model computational time step). The Soil and Water Assessment Tool model was used to estimate runoff and hydrographs. Different representations of the spatial data resulted in comparable model performances and even the use of uniform land use and soil type maps, instead of spatially distributed, was not noticeable. It was found that, although spatially distributed data help understand the characteristics of the watershed and provide valuable information to distributed hydrologic models, when the watershed is small, realistic representations of the spatial data do not necessarily improve the model performance. The results obtained from this study provide insights on the relevance of taking into account the spatial distribution of land use, soil type, and precipitation when modeling small watersheds.     

Spatial Variations in the Relationships between Land Use and Water Quality across an Urbanization Gradient in the Watersheds of Northern Georgia, USA

A spatial statistical technique, Geographically Weighted Regression (GWR) is applied to study the spatial variations in the relationships between four land use indicators, including percentages of urban land, forest, agricultural land, and wetland, and eight water quality indicators including specific conductance (SC), dissolved oxygen, dissolved nutrients, and dissolved organic carbon, in the watersheds of northern Georgia, USA. The results show that GWR has better model performance than ordinary least squares regression (OLS) to analyze the relationships between land use and water quality. There are great spatial variations in the relationships affected by the urbanization level of watersheds. The relationships between urban land and SC are stronger in less-urbanized watersheds, while those between urban land and dissolved nutrients are stronger in highly-urbanized watersheds. Percentage of forest is an indicator of good water quality. Agricultural land is usually associated with good water quality in highly-urbanized watersheds, but might be related to water pollution in less-urbanized watersheds. This study confirms the results obtained from a similar study in eastern Massachusetts, and so suggest that GWR technique is a very useful tool in water environmental research and also has the potential to be applied to other fields of environmental studies and management in other regions.     

Agricultural Abandonment in the North Eastern Iberian Peninsula: The Use of Basic Landscape Metrics to Support Planning

Land abandonment is an important cause of changes in landscape patterns in the Mediterranean area. There is a need to monitor land use and land cover changes in order to provide quantitative evidence of the relationship between land abandonment and the formation of new landscape patterns. Appropriate management policies to encourage sustainable development can then be developed. This paper describes how to monitor landscape dynamics using different temporal land use and land cover data generated from field survey and airborne information. The results showed that the abandonment of agricultural land generally results in an increase of vegetation biomass. This process leads to homogenization of the landscape. In addition, abandonment promotes fragmentation of agricultural land. Based on these results, the paper discusses the implications for rural management policies concerning the abandonment of agricultural land and suggests recommendations for the development of such policies.     

A Multi‐Scale Analysis of Single‐Family Residential Water Use in the Phoenix Metropolitan Area

Studies that evaluate determinants of residential water demand typically use data from a single spatial scale. Although household‐scale data are preferred, especially when econometric models are used, researchers may be limited to aggregate data. There is little, if any, empirical analysis to assess whether spatial scale may lead to ecological fallacy problems in residential water use research. Using linear mixed‐effects models, we compare the results for the relationship of single‐family water use with its determinants using data from the household and census tract scales in the city of Phoenix. Model results between the household and census tract scale are similar suggesting the ecological fallacy may not be significant. Common significant determinants on these two spatial scales include household size, household income, house age, pool size, irrigable lot size, precipitation, and temperature. We also use city/town scale data from the Phoenix metropolitan area to parameterize the linear mixed‐effects model. The difference in the parameter estimates of those common variables compared to the first two scales indicates there is spatial heterogeneity in the relationship between single‐family water use and its determinants among cities and towns. The negative relationship between single‐family house density and residential water use suggests that residential water consumption could be reduced through coordination of land use planning and water demand management.     

Land use change analysis in the Zhujiang Delta of China using satellite remote sensing,GIS and stochastic modelling

Rapid land use change has taken place in many coastal regions of China such as the Zhujiang Delta over the past two decades due to accelerated industrialization and urbanization. In this paper, land use change dynamics were investigated by the combined use of satellite remote sensing, geographic information systems (GIS), and stochastic modelling technologies. The results indicated that there has been a notable and uneven urban growth and a tremendous loss in cropland between 1989 and 1997. The land use change process has shown no sign of becoming stable. The study demonstrates that the integration of satellite remote sensing and GIS was an effective approach for analyzing the direction, rate, and spatial pattern of land use change. The further integration of these two technologies with Markov modelling was found to be beneficial in describing and analyzing land use change process.     

开发区土地集约利用评价——以辽宁炮台经济开发区为例

综合调查分析大连市炮台开发区土地集约利用现状，建立土地集约利用评价指标体系，利用特尔斐法确定指标权重，进而计算土地集约利用度，并分别从扩展潜力、结构潜力、强度潜力、管理潜力四个方面计算土地集约利用强度。综合分析土地集约利用度与土地集约利用潜力强度计算结果表明，炮台开发区土地集约度分值达到86．16％，土地集约利用水平较高，土地利用强度潜力较小。未来土地利用潜力主要为扩展潜力，不存在管理潜力，从而对炮台开发区未来发展土地集约利用提出相应建议与措施。     

The impact of land use and land cover changes on land surface temperature in a karst area of China

Satellite images have been used extensively to study temporal changes in land use and land cover (LULC) in China. However, few studies have been conducted in the karst areas despite the large area and population involved and the fragile ecosystem. In this study, LULC changes were examined in part of Guizhou Province of southern China from 1991 to 2001 based on Landsat Thematic Mapper (TM) images of November 7, 1991, December 5, 1994, and December 19, 2001. Land surface temperature (LST) and normalized difference vegetation index (NDVI) were computed based on LULC types. The results show that agricultural land decreased, while urban areas expanded dramatically, and forest land increased slightly. Barren land increased from 1991 to 1994, and then decreased from 1994 to 2001. These changes in LULC widened the temperature difference between the urban and the rural areas. The change in LST was mainly associated with changes in construction materials in the urban area and in vegetation abundance both in the urban and rural areas. Vegetation had a dual function in the temperatures of different LULC types. While it could ease the warming trend in the urban or built-up areas, it helped to keep other lands warmer in the cold weather. The study also reveals that due to the government's efforts on reforestation, rural ecosystems in some of the study area were being restored. The time required for the karst ecosystem to recover was shorter than previously thought.     

Managing the adverse thermal effects of urban development in a densely populated Chinese city

Guangzhou city in South China has experienced an accelerated urban development since the 1980s. This paper examines the impact of the urban development on urban heat islands through a historical analysis of urban-rural air temperature differences. Remote sensing techniques were applied to derive information on land use/cover and land surface temperatures and to assess the thermal response patterns of land cover types. The results revealed an overriding importance of urban land cover expansion in the changes in heat island intensity and surface temperature patterns. Urban development was also related to a continual air temperature increase in the 1980s and 1990s. The combined use of satellite-derived vegetation and land cover distributions with land surface temperature maps provides a potential useful tool for many planning applications. The city's greening campaigns and landscaping designs should consider the different cooling effects of forest, shrubs and grassy lawns for temperature control and should plant more tall trees.     

Impact of Urban Sprawl on Water Quality in Eastern Massachusetts,USA

A study of water quality, land use, and population variations over the past three decades was conducted in eastern Massachusetts to examine the impact of urban sprawl on water quality using geographic information system and statistical analyses. Since 1970, eastern Massachusetts has experienced pronounced urban sprawl, which has a substantial impact on water quality. High spatial correlations are found between water quality indicators (especially specific conductance, dissolved ions, including Ca, Mg, Na, and Cl, and dissolved solid) and urban sprawl indicators. Urbanized watersheds with high population density, high percentage of developed land use, and low per capita developed land use tended to have high concentrations of water pollutants. The impact of urban sprawl also shows clear spatial difference between suburban areas and central cities: The central cities experienced lower increases over time in specific conductance concentration, compared to suburban and rural areas. The impact of urban sprawl on water quality is attributed to the combined effects of population and land-use change. Per capita developed land use is a very important indicator for studying the impact of urban sprawl and improving land use and watershed management, because inclusion of this indicator can better explain the temporal and spatial variations of more water quality parameters than using individual land use or/and population density.     

Quantifying Terrestrial Ecosystem Carbon Dynamics in the Jinsha Watershed, Upper Yangtze, China from 1975 to 2000

Quantifying the spatial and temporal dynamics of carbon stocks in terrestrial ecosystems and carbon fluxes between the terrestrial biosphere and the atmosphere is critical to our understanding of regional patterns of carbon budgets. Here we use the General Ensemble biogeochemical Modeling System to simulate the terrestrial ecosystem carbon dynamics in the Jinsha watershed of China’s upper Yangtze basin from 1975 to 2000, based on unique combinations of spatial and temporal dynamics of major driving forces, such as climate, soil properties, nitrogen deposition, and land use and land cover changes. Our analysis demonstrates that the Jinsha watershed ecosystems acted as a carbon sink during the period of 1975–2000, with an average rate of 0.36 Mg/ha/yr, primarily resulting from regional climate variation and local land use and land cover change. Vegetation biomass accumulation accounted for 90.6% of the sink, while soil organic carbon loss before 1992 led to a lower net gain of carbon in the watershed, and after that soils became a small sink. Ecosystem carbon sink/source patterns showed a high degree of spatial heterogeneity. Carbon sinks were associated with forest areas without disturbances, whereas carbon sources were primarily caused by stand-replacing disturbances. It is critical to adequately represent the detailed fast-changing dynamics of land use activities in regional biogeochemical models to determine the spatial and temporal evolution of regional carbon sink/source patterns.     

兰西城市群县域土地利用效率时空差异研究

在考虑绿色发展内涵的基础上,运用SBM-Undesirable模型测度了2006—2018年兰西城市群县域土地利用效率值,并采用泰尔指数、空间自相关方法揭示其时空差异特征。结果表明:①2006—2018年兰西城市群县域土地利用效率稳步提升,区域差异先扩大后缩小。②兰西城市群县域土地利用效率呈现“中部高—外围低、西高东低、南北分异”的空间差异规律,两省域呈现“西—东”的递减规律。③兰西城市群县域土地利用效率空间集聚特征显著,局部范畴上高—高集聚区在中部地区较为典型,低—低集聚区出现由东南向西南的扩散现象。     

Water Quality and Plankton in the United States Nearshore Waters of Lake Huron

Our goal in the development of a nearshore monitoring method has been to evaluate and refine an in situ mapping approach to assess the nearshore waters across the Great Lakes. The report here for Lake Huron is part of a broader effort being conducted across all five Great Lakes. We conducted an intensive survey for the United States nearshore of Lake Huron along a continuous shoreline transect (523?km) from Port Huron, Michigan, to Detour Passage. A depth contour of 20?m was towed with a conductivity-temperature depth profiler, fluorometer, transmissometer, and laser optical plankton counter. Multiple cross-contour tows (10-30?m) on the cruise dates were used to characterize the variability across a broader range of the nearshore. The cross-contour tows were comparable with the alongshore contour indicating that the 20-m contour does a good job of representing the nearshore region (10-30?m). Strong correlations were observed between water quality and spatially associated watershed land use. A repeat tow separated by several weeks investigated temporal variability in spatial patterns within a summer season. Strong correlations were observed across each variable for the temporal repeat across broad- and fine-scale spatial dimensions. The survey results for Lake Huron nearshore are briefly compared with a similar nearshore survey in Lake Superior. The biomass concentrations of lower food web components of Lake Huron were notably approximately 54-59?% of those in Lake Superior. The towed instrumentation survey supported the recent view of a change in Lake Huron to an ultra-oligotrophic state, which has been uncharacteristic in recent history.     

Modeling the relationship between land use and surface water quality

It is widely known that watershed hydrology is dependent on many factors, including land use, climate, and soil conditions. But the relative impacts of different types of land use on the surface water are yet to be ascertained and quantified. This research attempted to use a comprehensive approach to examine the hydrologic effects of land use at both a regional and a local scale. Statistical and spatial analyses were employed to examine the statistical and spatial relationships of land use and the flow and water quality in receiving waters on a regional scale in the State of Ohio. Besides, a widely accepted watershed-based water quality assessment tool, the Better Assessment Science Integrating Point and Nonpoint Sources (BASINS), was adopted to model the plausible effects of land use on water quality in a local watershed in the East Fork Little Miami River Basin. The results from the statistical analyses revealed that there was a significant relationship between land use and in-stream water quality, especially for nitrogen, phosphorus and Fecal coliform. The geographic information systems (GIS) spatial analyses identified the watersheds that have high levels of contaminants and percentages of agricultural and urban lands. Furthermore, the hydrologic and water quality modeling showed that agricultural and impervious urban lands produced a much higher level of nitrogen and phosphorus than other land surfaces. From this research, it seems that the approach adopted in this study is comprehensive, covering both the regional and local scales. It also reveals that BASINS is a very useful and reliable tool, capable of characterizing the flow and water quality conditions for the study area under different watershed scales. With little modification, these models should be able to adapt to other watersheds or to simulate other contaminants. They also can be used to study the plausible impacts of global environmental change. In addition, the information on the hydrologic effects of land use is very useful. It can provide guidelines not only for resource managers in restoring our aquatic ecosystems, but also for local planners in devising viable and ecologically-sound watershed development plans, as well as for policy makers in evaluating alternate land management decisions.     

Mapping the vulnerability of groundwater to the contamination of four carbonate aquifers in Europe

The vulnerability of four European aquifers with different hydrogeological and climatic characteristics was evaluated using the COP method. The results obtained were statistically analyzed by determination coefficients to measure which factor has greater importance in the vulnerability index. Furthermore, a new parameter has been designed to measure the vulnerability for the whole of the aquifer. The results demonstrate that COP is a useful method to assess the vulnerability of the test sites under consideration. The results obtained are coherent with the conceptual model of each pilot aquifer and the available hydrogeological information (hydrographs, isotopic data, tracer tests). Fissured carbonate aquifers (diffuse flow systems) are less vulnerable than karst aquifers (conduit flow systems) and the vulnerability index is more positively correlated with the O factor (unsaturated zone protection capacity) in the first case. The karst aquifers are more vulnerable than fissured aquifers and they show a higher correlation between the C factor (karst features) and the vulnerability index. Climatic variation (precipitation for example) influences the final vulnerability index of the aquifers according to the weight in the index and the spatial distribution.     

WATER QUALITY CHARACTERISTICS OF STORM WATER FROM MAJOR LAND USES IN SOUTH FLORIDA1

ABSTRACT: Starting in 1998, a study was conducted to characterize storm water quality from predominant land use types in a coastal watershed along the south central coast of Florida, namely citrus, pasture, urban, natural wetland, row crop, dairy, and golf courses. Sixty‐three sampling sites were located at strategic points on drainage conveyances for each of seven specific land use areas. Runoff samples were collected following storm events that met defined rainfall criteria for a period of 30 months. Nitrogen (N), phosphorus (P), heavy metals, pesticides, and other water quality parameters were determined, and the results were analyzed to compare and characterize land uses as relative sources for these constituents in runoff. Results showed that runoff from most land use types had low dissolved oxygen concentration and that sediment and nutrient concentrations were closely related to land use, particularly to the amount of fertilizer applied in each land use. Among the eight heavy metals tested, copper was the most frequently detected and was mostly associated with runoff from citrus and golf course land uses. High levels of arsenic were also detected in golf course runoff. The most frequently detected pesticide was simazine from citrus. The information and methodologies presented may facilitate pollution source characterization and ecological restoration efforts.     

Effects of Impervious Cover at Multiple Spatial Scales on Coastal Watershed Streams1

Abstract: The spatial scale and location of land whose development has the strongest influence on aquatic ecosystems must be known to support land use decisions that protect water resources in urbanizing watersheds. We explored impacts of urbanization on streams in the West River watershed, New Haven, Connecticut, to identify the spatial scale of watershed imperviousness that was most strongly related to water chemistry, macroinvertebrates, and physical habitat. A multiparameter water quality index was used to characterize regional urban nonpoint source pollution levels. We identified a critical level of 5% impervious cover, above which stream health declined. Conditions declined with increasing imperviousness and leveled off in a constant state of impairment at 10%. Instream variables were most correlated (0.77 ≤ |r| ≤ 0.92, p < 0.0125) to total impervious area (TIA) in the 100‐m buffer of local contributing areas (～5‐km² drainage area immediately upstream of each study site). Water and habitat quality had a relatively consistent strong relationship with TIA across each of the spatial scales of investigation, whereas macroinvertebrate metrics produced noticeably weaker relationships at the larger scales. Our findings illustrate the need for multiscale watershed management of aquatic ecosystems in small streams flowing through the spatial hierarchies that comprise watersheds with forest‐urban land use gradients.