石羊河流域土地利用类型变化与转换效果分析

石羊河流域水土资源的供需状况成为决定该地区发展的生命线。随着地区社会经济的发展,土地利用的格局、深度和强度在不断变化,土地利用的类型也趋于多样化。利用石羊河流域1980年、1990年、2010年三期土地现状数据分析该流域各县市的土地利用类型的变化,比较1980—1990年、1990—2010年两个时段土地利用转换,引入上升性理论与方法分析两个时段土地利用类型转移的整体效果。从分析结果来看,随着土地利用类型的转移,整体上提高了石羊河流域土地资源利用的效益与效率,提升了流域土地利用的发展潜力空间。     

村级土地利用规划中的土地利用分区

为在村级土地利用规划中科学划分土地利用区,有效落实规划任务、实现规划目标,在分析村级土地利用规划特点的基础上,明确土地利用分区的任务与原则,探索建立了由产业功能区与土地用途区构成的两级分区类型体系,提出了公众参与为主、GIS技术为辅的分区方法.两级分区类型体系有利于实现土地组织利用、生产经营管理和土地利用管理的一体化.同时,在土地利用分区中贯穿公众参与式方法,有利于构建村内民主管理和业主参与土地利用管理的体制.     

喀什市土地利用对生态环境的影响分析

喀什市土地利用总体规划实施以来,土地利用变化对生态环境的影响显著,文章从土地沙化、土壤盐渍化、水环境情况、土壤地膜污染、土壤肥力、生物多样性、沙尘暴、大气污染物时空分布特征等方面分析了喀什市土地生态环境现状,通过分析土地利用规模、结构和布局及基础设施建设、土地开发整理和重大生态建设工程对生态环境的影响,提出喀什市生态改善目标及用地建议.     

秦皇岛市土地利用结构与土壤侵蚀空间格局分析

利用3S技术和景观生态学原理，以小流域为单元对秦皇岛市土地利用结构和土壤侵蚀等级类型进行空间分析，得出了不同土地利用结构所占面积和不同土壤侵蚀类型所占面积及分布小流域，并详细分析了秦皇岛市土壤侵蚀的主要影响因子和不同土地利用结构侵蚀现状。     

贵港市土地利用动态变化分析及用地预测

以城市为中心的区域土地是土地资源中资产效益最高的一部分，是人类利用土地影响最为深刻的土地类型。在分析土地利用现状变更调查数据的基础上，应用各类土地利用动态变化模型对贵港市的土地利用动态变化进行分析，并运用灰色系统预测模型对该区域各地类的土地利用时空演变进行了预测，最后提出相应的优化土地利用结构的建议。     

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。     

吉林省城市化进程中土地资源的可持续利用分析

“十一五”期间,吉林省城市化稳步发展,但在快速城市化的同时,土地利用方面出现了一些问题.从城市化角度出发,研究吉林省城市化发展与土地利用之间的内在联系,认为其存在的农业大省与城市扩展中占用耕地矛盾并存、土地集约利用水平偏低且浪费现象严重、土地利用类型变更混乱、土地利用环境问题严重等问题,提出解决城市化进程中土地可持续利用的对策.     

基于DEM的土地利用类型与地形因子关系研究——以重庆市永川朱龙花等6村为例

以重庆市永川区陈食街道朱龙花等6村为例,基于全国二次调查土地利用现状图和数字高程模型(DEM),在ArcGIS 9.3平台支持下,进行了30m×30m栅格单元的土地利用与地形因子关系研究,探讨了重庆市永川土地利用特征。结果表明,海拔高度、坡度和坡向与土地利用类型的综合分析有助于从定量剖析土地利用空间分布特征;朱龙花等6村海拔、坡度及坡向均值分别为345m、17.28°和271.25°(西坡);采用高程分带、坡度分级及坡向分类的方法能直观展示土地利用格局特征。耕地(水田及旱地)主要分布在低海拔的平原和丘陵上,阳坡面积大于阴坡,水田尤为突出。园地和林地主要分布在海拔低于400m的丘陵上,坡度小于15°,西坡和西北坡分布最多;草地主要分布在海拔200—500m的平原和丘陵上,坡度小于25°,各坡向均有少量分布;水域、水利建设用地、城镇村及工矿用地分布格局类似,主要分布在300—400m的丘陵上,坡度小于6°,东坡、东南坡分布较多;其他土地分布在海拔低于500m,坡度小于25°,西坡分布较多。从土地利用与生态环境的协调发展角度看,该区域土地利用空间分布格局基本符合生态环境建设的要求,约有2.34hm2的耕地位于坡度大于25°的缓陡坡和陡坡上,应继续推行退耕还林、还草。研究结果表明,地形因子对土地利用的空间格局的影响较大;同一地形因子不同级别下的土地主导利用方式各异,土地利用类型的优势区域不尽相同。     

川中丘陵区土地资源的可持续利用——以乐至县为例

川中丘区是四川省粮食经济作物的主产区，土壤肥沃、耕地少、土地利用复杂。以乐至县为例，探讨了该县土地资源的可持续利用。     

土地利用变化与转移对生态服务价值评估的影响

水土资源的供需状况成为决定地区发展的生命线。随着地区社会经济的发展,土地开发与利用的格局、深度和强度不断变化,类型趋于多样化。利用石羊河流域1980年、1990年、2010年三期土地现状数据,分析石羊河流域各县市土地利用类型的变化,比较1980—1990年、1990—2010年两个时段土地利用类型变化与转换情况,评估土地利用类型变化与转移引起的生态服务价值变化,揭示考虑该因素与否两种情形下对生态服务价值评估结果的影响作用。结合流域生态保护和恢复的理论意义与石羊河近年来流域综合治理工程的实效,并从流域居民环境红利的真实感知来看,考虑该因素的评估结果更加科学、合理与可信。     

面向市场的小流域土地资源合理利用--以黄塔小流域为例

分析了小流域农业发展状况及立体结构,详细阐述了畜牧业和经济林市场,提出小流域合理利用土地资源的措施:调整农业产业结构,充分利用土地,搞好小流域综合立体开发,改良品种,实现农业产业化.     

Relationship of Land‐Use/Land‐Cover Patterns and Surface‐Water Quality in The Mullica River Basin1

Abstract: We describe relationships between pH, specific conductance, calcium, magnesium, chloride, sulfate, nitrogen, and phosphorus and land‐use patterns in the Mullica River basin, a major New Jersey Pinelands watershed, and determine the thresholds at which significant changes in water quality occur. Nonpoint sources are the main contributors of pollutants to surface waters in the basin. Using multiple regression and water‐quality data for 25 stream sites, we determine the percentage of variation in the water‐quality data explained by urban land and upland agriculture and evaluate whether the proximity of these land uses influences water‐quality/land‐use relationships. We use a second, independently collected water‐quality dataset to validate the statistical models. The multiple‐regression results indicate that water‐quality degradation in the study area is associated with basin‐wide upland land uses, which are generally good predictors of water‐quality conditions, and that both urban land and upland agriculture must be included in models to more fully describe the relationship between watershed disturbance and water quality. Including the proximity of land uses did not improve the relationship between land use and water quality. Ten‐percent altered‐land cover in a basin represents the threshold at which a significant deviation from reference‐site water‐quality conditions occurs in the Mullica River basin.     

FORECASTING FUTURE LAND USE FOR WATERSHED ASSESSMENT1

ABSTRACT: Protecting surface water quality in watersheds undergoing demographic change requires both the management of existing threats and planning to address potential future stresses arising from changing land use. Many reservoirs and threatened waterbodies are located in areas undergoing rapid population growth, and increases in density of residential and commercial land use, accompanied by increased amount of impervious surface area, can result in increased pollutant loading and degradation of water quality. Effective planning to address potential threats, including zoning and growth management, requires analytical tools to predict and compare the impacts of different management options. The focus of this paper is not on developing demographic projections, but rather the translation of such projections into changes in land use which form the basis for assessment of future watershed loads. Land use change can be forecast at a variety of spatial and temporal scales. A semi-lumped, GIS-based, transition matrix approach is recommended as consistent with the level of complexity achievable in most watershed models. Practical aspects of forecasting future land use for watershed assessment are discussed. Several recent reservoir water supply projection studies are used to demonstrate a general framework for simulating changes in land use and resulting impacts on water quality. In addition to providing a technical basis for selecting optimal management alternatives, such a tool is invaluable for demonstrating to different stakeholder groups the trade-offs among management alternatives, both in terms of water quality and future land use patterns within the watershed.     

Long-term dynamics in land resource use and the driving forces in the Beressa watershed, highlands of Ethiopia

Land degradation in the Ethiopian highlands is considered to be one of the major problems threatening agricultural development and food security in the country. However, knowledge about the forces driving the long-term dynamics in land resources use is limited. This research integrates biophysical information with socio-economic processes and policy changes to examine the dynamics of land resource use and farmers' livelihoods in the Beressa watershed for over 40 years during the second half of the 20th century. It was found that there have been substantial dynamics in land resource use in the area. The natural vegetation cover has been extensively cleared, although most of the cleared areas have since been replaced with plantations. Grazing land has expanded remarkably at the expense of cropland and bare land. However, the expansion of cropland was minimal over the 43-year period despite a quadrupling of the population density. Yields have not increased to compensate for the reduction in per capita cropland, and the soil quality appears to be not that good. Though the farmers perceived it otherwise, the long-term rainfall pattern has improved. In response to soil degradation, water shortage, socio-economic and policy changes, farmers have tended to gradually change from annual cropping to tree planting and livestock production to cope with the problems of soil degradation, water scarcity and smaller farms. Income diversification through the sale of wood and cattle dung is becoming a major livelihood strategy. Apparently, however, little attention has been paid to investments in soil and water conservation (SWC) and local soil fertility amendments. In particular, increased erosion and related high nutrient losses in sediments, as well as the removal of potentially available soil nutrients through the sale of manure threatens to damage agricultural sustainability in the area.     

基于RS的农业生产方式变化对区域景观生态的影响分析——以新疆玛纳斯县农业为例

21世纪初的玛纳斯县域土地利用面临新的政策和技术背景,采用遥感技术对2000年和2005年玛纳斯县域人类主要活动区各类景观进行比对分析,发现研究区内耕地、城镇景观面积出现大幅增长,林地、草地景观面积显著下降,“农林”、“农草”争水、争地的矛盾逐渐激化,水资源的供需处于“紧平衡”状态,区域景观生态系统的多样性、稳定性降低。分析表明农业产业组织形式的创新和农业节水灌溉技术的突破是玛纳斯县域景观生态变化的关键因子。     

ASSESSING LAND USE IMPACTS ON WATER QUALITY USING MICROBIAL SOURCE TRACKING1

ABSTRACT: A renewed emphasis on source water protection and watershed management has resulted from recent amendments and initiatives under the Safe Drinking Water Act and the Clean Water Act. Knowledge of the impact of land use choices on source water quality is critical for efforts to properly manage activities within a watershed. This study evaluated qualitative relationships between land use and source water quality and the quantitative impact of season and rainfall events on water quality parameters. High levels of specific conductance tended to be associated with dense residential development, while organic carbon was elevated at several forested sites. Turbidity was generally higher in more urbanized areas. Source tracking indicators were detected in samples where land use types would predict their presence. Coliform levels were statistically different at the 95 percent confidence levels for winter versus summer conditions and dry versus wet weather conditions. Other water quality parameters that varied with season were organic carbon, turbidity, dissolved oxygen, and specific conductance. These results indicate that land use management can be effective for mitigating impacts to a water body; however, year‐ round, comprehensive data are necessary to thoroughly evaluate the water quality at a particular site.     

MINIMIZING THE IMPACT OF URBANIZATION ON LONG TERM RUNOFF1

Increasing concern about the problems caused by urban sprawl has encouraged development and implementation of smart growth approaches to land use management. One of the goals of smart growth is water resources protection, in particular minimizing the runoff impact of urbanization. To investigate the magnitude of the potential benefits of land use planning for water resources protection, possible runoff impacts of historical and projected urbanization were estimated for two watersheds in Indiana and Michigan using a long term hydrological impact analysis model. An optimization component allowed selection of land use change placements that minimize runoff increase. Optimizing land use change placement would have reduced runoff increase by as much as 4.9 percent from 1973 to 1997 in the Indiana study watershed. For nonsprawl and sprawl scenarios in the Michigan watershed for 1978 to 2040, optimizing land use change placement would have reduced runoff increase by 12.3 percent and 20.5 percent, respectively. The work presented here illustrates both an approach to assessing the magnitude of the impact of smart growth and the significant potential scale of smart growth in moderating runoff changes that result from urbanization. The results of this study have significant implications for urban planning.     

EFFECTS OF URBANIZATION ON CHANNEL INSTABILITY1

ABSTRACT: Channel instability and aquatic ecosystem degradation have been linked to watershed imperviousness in humid regions of the U.S. In an effort to provide a more process‐based linkage between observed thresholds of aquatic ecosystem degradation and urbanization, standard single event approaches (U.S. Geological Survey Flood Regression Equations and rational) and continuous hydrologic models (HSPF and CASC2D) were used to examine potential changes in flow regime associated with varying levels of watershed imperviousness. The predicted changes in flow parameters were then interpreted in concert with risk‐based models of channel form and instability. Although low levels of imperviousness (10 to 20 percent) clearly have the potential to destabilize streams, changes in discharge, and thus stream power, associated with increased impervious area are highly variable and dependent upon watershed‐specific conditions. In addition to the storage characteristics of the pre‐development watershed, the magnitude of change is sensitive to the connectivity and conveyance of impervious areas as well as the specific characteristics of the receiving channels. Different stream types are likely to exhibit varying degrees and types of instability, depending on entrenchment, relative erodibility of bed and banks, riparian condition, mode of sediment transport (bedload versus suspended load), and proximity to geomorphic thresholds. Nonetheless, simple risk‐based analyses of the potential impacts of land use change on aquatic ecosystems have the potential to redirect and improve the effectiveness of watershed management strategies by facilitating the identification of channels that may be most sensitive to changes in stream power.     

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.