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131.
ABSTRACT

Old cadastral maps represent a historical reference dataset for long-term land-use reconstructions. This study presents identification of inconsistencies in the nineteenth century Franziscean cadastre, one of the largest sets of old cadastral maps worldwide, by comparing three versions of the maps and written documents created in the same period. We identified all parcels and their land-use in the four sub-sources in six study areas. The overall share of inconsistencies among 5 771 identified parcels is 7.4%, with the biggest share of inconsistency in agroforestry and forestry classes. The most frequent inconsistencies are of ‘Not differentiable land use’ (n = 212) and ‘Different land-use’ categories across the sub-sources (n = 113). We conclude that the frequency of uncertainties in old cadastral maps may limit the validity of historical land-use reconstructions, affecting the eventual restoration and management efforts based on such data. We provide a summary for the use of Franziscean cadastre.  相似文献   
132.
Assessing Land-Use Impacts on Natural Resources   总被引:3,自引:1,他引:2  
/ Much information is available on changes that occur in natural resources from both spatially-explicit data on environmental conditions and models of the interactions of these conditions and resources with human activities. The strategy for assessing land-use impacts on natural resources developed in this paper provides a framework for using relevant data and models to address questions of how management practices can promote both use and protection of resources. This assessment strategy integrates spatially explicit environmental data using geographic information systems (GIS) with computer models that simulate changes in land cover in response to land-use impacts. The computer models also simulate susceptibility of species to changes in habitat suitability and landscape patterns. The approach is applied to management of limestone barrens on the Oak Ridge Reservation in East Tennessee. Potential limestone barrens habitats are identified by overlaying appropriate soils, geology, slope, and land-use/land-cover conditions. Their validity is tested against known sites containing rare species that occur in these habitats. The location of habitats at risk in the aftermath of human activities is determined by using an available area model that identifies the size and proximity of sites that particular types of species can no longer use as habitat. The resulting risk map can be used in land management planning. The approach uses readily available in situ and remotely sensed data and is applicable to a wide range of locations and land-use scenarios. This approach can be refined based on needs identified by land managers and on the sensitivity of the results to the resolution of available resource information.KEY WORDS: Land management; Assessment; Habitat characterization; Limestone barrens; Ecological modeling; Geographic information systems  相似文献   
133.
介绍了侧联式球磨机噪声产生原理及其噪声控制方法,选择了制作局部式隔声罩的噪声控制设计和装置结构.在中国铝业中州分公司热电厂球磨机上应用,取得了很好的隔声效果.  相似文献   
134.
Chronosequences are useful to evaluate long-term changes in ecosystem services but assessing groundwater quality changes using this approach has rarely been done. In this study, groundwater level and quality comparisons were made in a watershed-scale reconstructed prairie chronosequence that extended back in time approximately 13 years at the Neal Smith National Wildlife Refuge (NSNWR) near Prairie City, Iowa. Our objectives were to determine whether groundwater conditions varied significantly across the chronosequence and quantify the rate of nitrate concentration reduction when row crop fields are replaced by prairie. We installed 19 groundwater wells at upland locations selected to provide similar soil type, landscape position and slope. Water samples were collected on five occasions in 2006 and 2007 and analyzed for field parameters, anions and NO3-N, NH4-N and PO4-P. Significant groundwater changes were primarily associated with groundwater levels, and groundwater nitrate and chloride concentrations. The groundwater was deeper under the older prairie plantings but fluctuated similarly among all well sites. Groundwater nitrate and chloride concentrations decreased 0.58 and 0.52 mg/l per year over the 13-year chronosequence, respectively. Results are seen to provide some guidance to land managers regarding possible nitrate concentration reductions achievable from converting cropland to perennial land cover in similar geomorphic settings.  相似文献   
135.
利用2002年和2006年公路建设前后的两期遥感数据,分析了公路对沿线土地利用和景观格局的影响。结果表明:公路建设使公路用地面积增加了4.10km^2,主要由侵占农业用地和沙地所导致;居民区、森林面积分别增加了1.12km^2和0.08km^2,其余土地利用类型面积有所减少;道路、居民区和森林的景观破碎化指数增加,农田、草地、灌木、沙地和水域下降;景观多样性指数增加,景观优势度降低。  相似文献   
136.
钼矿区污灌菜地土壤重金属污染的生态风险预警评价   总被引:1,自引:0,他引:1  
通过对钼矿区地下水进行重金属含量分析,发现地下水已受重金属污染。该受污染地下水为矿区菜地唯一灌溉用水。本文研究钼矿区污灌菜地土壤的重金属污染现状及生态风险。选取矿区、尾矿区、选矿区周边菜地的土壤样本60个,用HNO3-HF-HClO4处理后,采用等离子体发射光谱仪(ICP-AKS)测定土壤样品中Pb、As、Hg、Cr、Cd、Zn、Cu、Ni的全量,采用生态风险指数进行生态风险预警评价。结果表明:矿区、尾矿区、选矿区周边受污染菜地尾矿区农田土壤的生态风险指数(IER)分别为59.42、80.60、154.83,其预警类型均为重警;污染程度为矿区菜地〈尾矿区菜地〈选矿区菜地。  相似文献   
137.
The Ganges Delta in Bangladesh is an example of water‐related catastrophes in a major rural river basin where limitations in quantity, quality, and timing of available water are producing disastrous conditions. Water availability limitations are modifying the hydrologic characteristics especially when water allocation is controlled from the upstream Farakka Barrage. This study presents the changes and consequences in the hydrologic regime due to climate‐ and human‐induced stresses. Flow duration curves (FDCs), rainfall elasticity, and temperature sensitivity were used to assess the pre‐ and post‐barrage water flow patterns. Hydrologic and climate indices were computed to provide insight on hydro‐climatic variability and trend. Significant increases in temperature, evapotranspiration, hot days, heating, and cooling degree days indicate the region is heading toward a warmer climate. Moreover, increase in high‐intensity rainfall of short duration is making the region prone to extreme floods. FDCs depict a large reduction in river flows between pre‐ and post‐barrage periods, resulting in lower water storage capacity. The reduction in freshwater flow increased the extent and intensity of salinity intrusion. This freshwater scarcity is reducing livelihood options considerably and indirectly forcing population migration from the delta region. Understanding the causes and directions of hydrologic changes is essential to formulate improve water resources management in the region.  相似文献   
138.
Anticipating changes in hydrologic variables is essential for making socioeconomic water resource decisions. This study aims to assess the potential impact of land use and climate change on the hydrologic processes of a primarily rain‐fed, agriculturally based watershed in Missouri. A detailed evaluation was performed using the Soil and Water Assessment Tool for the near future (2020–2039) and mid‐century (2040–2059). Land use scenarios were mapped using the Conversion of Land Use and its Effects model. Ensemble results, based on 19 climate models, indicated a temperature increase of about 1.0°C in near future and 2.0°C in mid‐century. Combined climate and land use change scenarios showed distinct annual and seasonal hydrologic variations. Annual precipitation was projected to increase from 6% to 7%, which resulted in 14% more spring days with soil water content equal to or exceeding field capacity in mid‐century. However, summer precipitation was projected to decrease, a critical factor for crop growth. Higher temperatures led to increased potential evapotranspiration during the growing season. Combined with changes in precipitation patterns, this resulted in an increased need for irrigation by 38 mm representing a 10% increase in total irrigation water use. Analysis from multiple land use scenarios indicated converting agriculture to forest land can potentially mitigate the effects of climate change on streamflow, thus ensuring future water availability.  相似文献   
139.
The potential impacts driven by climate variability and urbanization in the Boise River Watershed (BRW), located in southwestern Idaho, are evaluated. The outcomes from Global Circulation Models (GCMs) and land use and land cover (LULC) analysis have been incorporated into a hydrological and environmental modeling framework to characterize how climate variability and urbanization can affect the local hydrology and environment at the BRW. The combined impacts of future climate and LULC change are also evaluated relative to the historical baseline conditions. For modeling exercises, Hydrological Simulation Program‐Fortran (HSPF) is used in parallel computing and statistical techniques, including spatial downscaling and bias correlation, are employed to evaluate climate consequences derived from GCMs as well. The implications of climate variability and land use change driven by urbanization are then observed to evaluate how these overall global challenges can affect water quantity and quality conditions at the BRW. The results show the combined impacts of both climate change and urbanization can lead to more seasonal variability of streamflow (from ?27.5% to 12.5%) and water quality, including sediment (from ?36.5% to 49.3%), nitrogen (from ?24% to 124.2%), and phosphorus (from ?13.3% to 21.2%) during summer and early fall over the next several decades.  相似文献   
140.
In the present study, a trapezoidal salt-gradient solar pond (TSGSP) has been investigated experimentally. The top surface of solar pond has been covered with double-glass cover in order to reduce the evaporative and convective losses from the top. This results in increase of temperature even in the top zone of the solar pond and leads to more volume utilization for heat storage in the pond. A reflector made of aluminium sheet has been used to enhance the solar intensity on the solar pond during sunny hours. A procedure, to determine optimum tilt angle of reflector in order to utilize maximum amount of solar energy at noon, has been proposed. The use of reflector enhanced the average solar intensity on the top surface of solar pond by 22%. The maximum average temperature of trapezoidal solar pond with glass cover and reflector has been observed to be 70.5°C. The thermal efficiencies of LCZ, NCZ and UCZ for the trapezoidal solar pond with double-glass cover and reflector have been estimated to be 32.73%, 23.22% and 5.30%, respectively. In addition to experimental investigation, the sunny area ratio of TSGSP has been theoretically computed and compared with the cuboid solar pond having same top surface area and depth in order to see the effect of pond shape on sunny area ratio. The average yearly sunny area ratio of trapezoidal solar pond has been determined to be 11% higher than that of cuboid one.  相似文献   
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