南水北调中线水源地汉江上游流域主要生态环境问题及对策

汉江上游是南水北调中线水源地，流域生态环境建设是保障水源地水质安全的关键。针对上游流域水环境污染、土地利用以及水土流失等重大生态环境问题，结合流域数字高程模型及水质调查对其进行了系统分析。结果表明：（1）丹江流域、库区流域及汉中盆地水质较差，CODMn和氨氮成为水源区主要污染物；（2）各子流域区植被覆盖占各自面积的712%~957%，表明流域植被覆盖较好，但沿河岸100 m范围内农业用地占292%~434%，且多为坡耕地；（3）流域水土流失严重，2000年左右流域侵蚀图显示汉江源头、秦岭南及大巴山北均出现了大片年均侵蚀模数>2 200 t/km2的区域，且有日益增强的趋势。提出加大水环境污染整治力度、加强农业用肥管理及河岸带建设、水土保持建设以及加强流域水环境及水土保持监测和科研工作等对策。     

汉江源土壤流失状况及生态效益测评

在通用土壤流失方程的基础上,提出了土壤侵蚀系数和土壤保持系数的概念和计算方法,用其对南水北调中线工程水源区土壤侵蚀状况及生态效益进行了测评,结果表明:(1)自然条件影响下,研究区潜在土壤侵蚀量大且空间分布差异显著,中高山区远大于河谷盆地区。(2)研究区实际土壤侵蚀量较小,但土壤侵蚀系数较大且空间分布规律性强。人类水土保持措施与土地利用方式对土壤侵蚀贡献率高,低山丘陵区土壤侵蚀系数最大,局部可达0.6,中高山及盆地区相对较小。(3)中高山区水土保持效益略有增加;河谷盆地及低山丘陵区明显减小。(4)低山丘陵区应成为今后水土保护工作的重点监控和治理区,也是应重点考虑的生态补偿区。     

山区生态补偿保护成本的空间差异研究

制定有空间差异的生态补偿标准是构建生态补偿机制的关键和难点。补偿标准的空间差异体现在提供的生态系统服务和付出的成本两个方面。其中,生态补偿保护成本因能准确反映某地关于生态系统保护的工作量和贡献程度而得到广泛关注。本研究针对山区自然因素和人文因素高度空间异质性的特点,以四川省雅安市宝兴县为例,利用GIS技术结合统计资料和实地调研,核算了研究区的保护成本。同时使用面积内插法并从距离、道路、坡度和方向4个方面评价斑块可达性难易程度,进行保护成本空间化研究。旨在为生态补偿标准的制定、生态补偿空间选择以及生态补偿效果评价提供参考和依据。结果显示:1通过考虑距离、道路、坡度和方向,计算得到宝兴县被管护林地的可达性系数,其范围在0—1之间,平均值为0.18,标准差为0.16。22010年,研究区流域生态补偿相关的保护成本为4 590.46万元,其中不同保护对象的投入大小顺序为林地自然保护区水土保持地草地水源保护地。3研究区不同海拔带保护成本及其构成不同,林地保护成本在1 000—4 000 m范围内均较高,这与研究区林地的广泛分布有关;草地保护成本集中在高海拔地区(3 000—4 500 m);而水源保护地保护成本集中在低海拔地区(1 000—2 500 m)。保护成本的核算准确性及空间化精度取决于对当地生态建设与保护措施的掌握程度和资料的收集、获取情况。本研究使用的可达性难易程度来调整保护成本的空间差异,是一种基于地理环境要素空间化思路和尝试。主要考虑距离、道路、坡度和方向4个方面,暂未考虑管护人员的交通工具、视域范围、办事效率等个体因素以及土地利用的限制。     

汉江流域生态系统服务权衡与协同关系演变

汉江流域是我国南水北调工程的水源地,也是国家重要的生态功能区,定量分析其生态系统服务关系对协调区域发展与保护环境有重要意义。综合利用RS与GIS技术对该区域2000～2015年的土壤保持、碳储量与食物供给服务进行空间制图,并基于空间采样法对3种生态系统服务间的权衡与协同关系进行研究。结果表明:(1)在2000～2015年,汉江流域土壤保持量在波动中下降,高值区位于汉江上游林地、草地交叉分布区域,低值区位于汉江中下游林地、耕地等单一聚集地类区;碳储量年际变化较小,其高低值分布与土壤保持量基本相同;食物供给量增长迅速,高值区位于中下游的平原区,低值区位于上游的山地和盆地区。(2)在权衡与协同分析中,碳储量与食物供给、土壤保持与食物供给之间以权衡关系为主,而碳储量与土壤保持以协同关系为主,各生态系统间权衡与协同关系存在空间异质性。(3)空间热点制图显示,2000～2015年0类服务热点区占比减少,主要地类为草地;1类服务热点区占比最大且呈增加趋势,主要地类为耕地,生态服务类型以食物供给为主;2类服务热点区有所减少,多分布在上游林地区域,服务类型为碳储存和土壤保持;3类服务热点区占比很少。该研究结果对揭示生态系统服务之间的区域差异有重要作用。     

基于InVEST模型的秦岭山地土壤流失及土壤保持生态效益评价

为了解秦岭山地土壤侵蚀及土壤保持生态服务功能的空间分布特征,采用InVEST 土壤保持模型,从研究区、流域、县域3个尺度,对其潜在与实际土壤侵蚀量进行计算,在此基础上进一步应用该模型量化研究区土壤保持生态服务价值,得到土壤保持服务价值空间分布图。研究结果表明：（1）2012年秦岭山地潜在与实际土壤侵蚀量分别为4588×108 t、152×108 t,五大流域和各县区以轻度侵蚀和中度侵蚀为主,较为严重的地区为汉江流域南部紫阳县6323 t/(hm2[DK]·a)[JP2]和岚皋县5869 t/(hm2[DK]·a),属强烈侵蚀。（2）全区土壤保持总量4337×108 t,[JP]其中泥沙持留量143×108 t,单位面积土壤保持量为71979 t/(hm2[DK]·a);减少泥沙疏浚工程和水质治理花费的土壤保持服务价值共计4184亿元。各县区土壤保持服务价值量在001亿元至475亿元不等,价值量在096~191亿元之间的县区占全区的4413%,其次为191~285亿元（2522%）。（3）对于秦岭山地土壤侵蚀的防治及其生态效益的建设,保证林地面积的绝对优势是首要条件;对于大于25°的坡耕地,应继续推行还林还草政策     

红壤坡地水土保持植物措施下柑橘林地水文生态效应

根据江西水土保持生态科技园2001～2008年不同处理措施柑橘林地径流小区的降雨产流产沙的定位观测资料及2010年土壤含水量测试数据,分析了坡面尺度水土保持植物措施下柑橘林地的产流产沙及土壤水分的特征,研究了狗牙根带状覆盖、狗牙根全园覆盖、果园清耕3种措施下的蓄水保土效应。结果表明：有草被覆盖的柑橘林小区的产流产沙量明显小于柑橘清耕小区,狗牙根带状覆盖小区减流减沙效果最好,减流率为98.21%,减沙率为99.84%。在大部分土层深度,草被带状覆盖下的土壤水分含量最高,均大于清耕措施,而全园覆盖由于植物蒸腾耗水量大水分含量反而低于带状覆盖。条带植草是防治柑橘林地水土流失的有效措施,具有明显的减流减沙效应和蓄积水分作用     

Ecosystem services and biodiversity conservation under forestation scenarios: options to improve management in the Vez watershed,NW Portugal

Ensuring forest protection and the delivery of forest ecosystem services is a central aim of the European Union’s biodiversity strategy for 2020. Therefore, accurate modelling and mapping of ecosystem services as well as of biodiversity conservation value is an important asset in support of spatial planning and policy implementation. The objectives of this study were to analyse the provision of the multiple ecosystem services under two forestation scenarios (eucalyptus/pine vs. oak) at the watershed scale and to evaluate their possible trade-offs with the biodiversity conservation value. The Vez watershed, in northwest Portugal, was used as case study area, in which soil and water assessment tool (SWAT) was applied to simulate the provision of hydrological services, biomass and carbon storage services. Biodiversity conservation value was based on nature protection regimes and on expert judgement applied to a land cover map. Results indicated large provision of ecosystem services in the high and low mountain sub-basins. The overall performance for water quantity and timing is better under the shrubland and oak forest scenarios, when compared to the eucalyptus/pine forest scenario, which perform better for flood regulation and erosion control services, especially in the low mountain sub-basin. The current shrubland dominated cover also shows good performance for the control of soil erosion. The oak scenario is the one with less trade-offs between forest services and biodiversity conservation. Results highlight SWAT as an effective tool for modelling and mapping ecosystem services generated at the watershed scale, thereby contributing to improve the options for land management.     

Impacts of predicted sea level rise on land use/land cover categories of the adjacent coastal areas of Mumbai megacity,India

Physical and ecological responses of the coastal areas in the vicinity of Mumbai, India, due to relative sea level rise are examined by different inundation scenarios. Evaluation of potential habitat loss under sea level rise was made by incorporating the land use/land cover (LULC) adopted from the digital elevation model with the satellite imagery. LULC categories overlaid on 1.0, 2.0, 3.0 and 4.0 m coastal elevation showed that the coastal areas of Mumbai were mostly covered by vegetation followed by barren land, agricultural land, urban areas and water bodies. For the relative sea level rise scenarios of 1.0, 2.0, 3.0 and 4.0 m, the tidal inundation areas were estimated to be 257.85, 385.58, 487.56 and 570.63 km², respectively, using GIS techniques. The losses of urban areas were also estimated at 25.32, 41.64, 54.61 and 78.86 km² for the 1.0, 2.0, 3.0 and 4.0 m relative sea level rise, respectively, which is most alarming information for the most populated city on the eastern coast of India. The results conclude that relative sea level rise scenario will lead profound impacts on LULC categories as well as on coastal features and landforms in the adjoining part of Mumbai. The sea level rise would also reduce the drainage gradients that promote flooding condition to rainstorms and subsequently increase saltwater intrusion into coastal regions. Alterations in the coastal features and landforms correlated with inundation characteristics that make the coastal region more vulnerable in the coming decades due to huge development activities and population pressures in Mumbai.     

洞庭湖流域分布式水文模型

流域出口径流观测序列是水文模型参数率定重要依据,不受水文站控制区域的模型应用是水文研究关注点之一。首先根据水文站观测资料建立洞庭湖流域四水控制站之上基于水文响应单元的分布式水文模型,在此基础上结合实验、同质移植和虚拟水库等方法,将分布式水文模型拓展到包含无径流站控制区域的丘陵区间和平原圩垸区,最终实现了洞庭湖全流域水文过程模拟。结果表明:在较完备土壤、地形、土地利用等空间数据支持下,通过合理的流域划分和水文响应单元定义,建立的流域分布式水文模型可以较好地在水文响应单元尺度反应降水发生后蒸散、地表径流、土壤和地下水的响应特征。而基于观测实验及基流分割等方法获取的关键水文过程特征对模型参数优化的认识,可以提高模型参数率定效率,在较少优化迭代运算后既可使月径流模拟的效率系数NSE和确定性系数R²值高于0.81(日过程高于0.62)。借助参数同质移植和虚拟水库解决了区间和圩垸区无控制站区域水文过程模拟。在全流域水文过程的模拟中,基流指数和蒸散比例与实际过程具有较好的一致性。说明相关参数较好地反映了其物理机制,具备在相似气候及下垫面条件区域进行同质移植的基础,圩垸区径流交换采用虚拟水库的处理方式也合理可行。     

基于物元可拓模型的水土保持综合效益评价

针对水土保持综合效益评价中信息屏蔽和单指标评价结果不相容的问题,采用物元可拓模型,对湖北省世行水土保持项目区的6个区域进行了综合效益评价,结果表明：项目区水土保持生态效益等级Ⅱ级以上的区域占整个项目区的833%,经济效益等级Ⅱ级以上的占50%,社会效益等级全部属于Ⅱ级以上,表明项目的实施产生了良好的生态、经济、社会效益;综合效益等级为Ⅱ级以上的占整个项目区的833%,项目整体上实施效果较好。利川水土保持综合效益等级为Ⅰ级,长阳和浠水水土保持综合效益具备向Ⅰ级转化的潜力,但长阳的转化潜力高于浠水。红安和麻城具有向Ⅲ级转化的潜力,夷陵水土保持综合效益等级最低。物元可拓模型评价结果与传统的综合指数评价法结果基本一致,表明该方法评价结果可靠。研究结果对水土保持综合效益评价方法体系建立具有一定意义,同时可为水土流失综合治理提供决策依据     

元谋干热河谷民营水土保持发展的驱动力研究

民营水土保持是当今水土保持生态建设中出现的一种新模式。以元谋干热河谷区为研究范围，通过对农户调查资料的分析，确定民营水土保持发展的驱动力因子为农户经济发展水平、农户兼业经济行为、农户家庭劳动力状况、农户经营规模、政府行为5大类，并对5大指标进行细化、量化，运用相关分析、因子分析等定量统计分析方法对元谋干热河谷区的民营水土保持发展的驱动力因子进行定量分析，结果表明，经济因子是影响民营水土保持发展的第一因子。     

长江流域土地利用/覆被变化的大尺度水文效应

土地利用/覆被变化(LUCC)对流域水文过程具有重要的长期影响作用。针对土地利用覆被变化对大型流域水文过程的影响程度,利用构建的长江流域分布式水文模型分析了土地利用变化情景下的水文效应特征。结果显示:分布式水文模型综合考虑了下垫面土壤、坡度、植被等特征,可以较好的反映降水发生后水分在不同土壤、植被和地形条组合件下,蒸散、地表和地下径流等组分的运移过程。根据不同土地覆被类型的径流成分差异,以及长江流域实际可供调节的土地利用方式,流域现有土地利用格局中农林地依然具有较大的转换空间。根据典型流域中预设的农林地转换情景下的径流效应看,各种情景虽然对流域径流总量变化影响较小,但对蒸散、地表径流和基流可以产生显著影响。其中,林地增加使基流最高提升超过15%,同时可使地表径流下降近5%,两者对蒸散的改变在1%左右,对径流总量变化幅度则只有0.7%左右。不同情景下的水文响应模式反映了未来土地利用调整的水文效应,因此可以基于不同的径流效应,开展有利于综合发挥流域持水能力的空间规划,提升林地所占比重。     

Analysis of the soil water balance for large-scale reforestation with <Emphasis Type="Italic">Eucommia ulmoides</Emphasis> in the hilly red soil region of southern China

Returning farmland to forests is important for the protection of ecological values. Eucommia ulmoides is considered to be a suitable species for reforestation in the hilly red soil region of southern China. The objective of this study was to investigate the relationship between the water supply and demand of an E. ulmoides plantation to provide insights into the feasibility of large-scale planting for ecological restoration and forest management activities in the hilly red soil region of southern China. With the measured precipitation, surface runoff and interflow and actual evapotranspiration (ET_c) estimated by the modified P–M model, soil water storage (SWS) was estimated based on the water balance equation. Monthly variations of SWS were then compared with in situ measured SWS. The results showed that the estimated mean monthly water losses (the sum of the surface runoff, interflow and ET_c) were 139.8 mm in a wet year and 120.0 mm in a dry year, while the measured mean monthly water input values (net precipitation) were 131.2 mm in a wet year and 70.8 mm in a dry year. Net soil water storage (ΔSWS) was negative in each month of the growing season in a dry year, but the soil water deficit was replenished during the following season. The model performance showed that the modified P–M model can be adapted to estimate the soil water storage in other forest catchments where no adequate in situ data are available. As a result of estimating the water balance and observing soil water storage in two different hydrological years, E. ulmoides is recommended as a suitable forest rehabilitation species in the study area, and a suitable plant region has been defined by the GIS technique based on the water balance model.     

Combining remote sensing and household level data for regional scale analysis of land cover change in the Brazilian Amazon

Land cover change in the Brazilian Amazon depends on the spatial variability of political, socioeconomic and biophysical factors, as well as on the land use history and its actors. A regional scale analysis was made in Rondônia State to identify possible differences in land cover change connected to spatial policies of land occupation, size and year of establishment of properties, accessibility measures and soil fertility. The analysis was made based on remote sensing data and household level data gathered with a questionnaire. Both types of analyses indicate that the highest level of total deforestation is found inside agrarian projects, especially in those established more than 20 years ago. Even though deforestation rates are similar inside and outside official settlements, inside agrarian projects forest depletion can exceed 50% at the property level within 10–14 years after establishment. The data indicate that both small-scale and medium to large-scale farmers contribute to deforestation processes in Rondônia State encouraged by spatial policies of land occupation, which provide better accessibility to forest fringes where soil fertility and forest resources are important determinants of location choice.     

土地利用变化情景下牧羊河水文响应研究

土地利用方式变化影响水量平衡各要素的分配,进而导致流域水源涵养能力发生变化。选用长江流域金沙江水系下段牧羊河小流域内及周边气象站气象资料,植被、土壤以及地形数据,构建了研究区SWAT水文模型,分析其在牧羊河适用性后,结合1986~2009年的土地利用以及设置的人类活动增强和生态环境改善的4种土地利用变化情景,用率定好的SWAT模型分析了土地利用变化下牧羊河水文响应。结果表明：径流依次按1986、2000、2009、1995年土地利用方式减小,而蒸散依次按2009、1986、2000、1995年土地利用方式减小,土地利用对径流和蒸散的影响在汛期大于非汛期,随着林地面积的增加径流将减小;将现有耕地变为林地或变为草地都有助于减少径流,从流域水源水量涵养角度出发,构建适宜的生态系统将有助于减少径流和蒸散,而增加入渗。这一结果为牧羊河水源涵养林建设提供科学依据     

The Potential of Soil Carbon Sequestration Through Improved Management Practices in Norway

The study was conducted to assess the potential of Norwegian agricultural ecosystems to sequester carbon (C) based on the data from some long-term agronomic and land use experiments. The total emission of CO₂ in Norway in 1998 was 41.4 million metric ton (MMT), of which agriculture contributed only 0.157 MMT, or <0.4% of the total emissions. With regards to methane (CH₄) and nitrous oxide (N₂O) gases, however, agricultural activities contributed 32.5% and 51.3% of their respective emissions in Norway. The soil organic carbon (SOC) losses associated with accelerated soil erosion in Norway are estimated at 0.475 MMTC yr^–1. Land use changes and soil/crop management practices with potential for SOC sequestration include conservation tillage methods, judicious use of fertilizers and manures, use of crop residues, diverse crop rotations, and erosion control measures. The potential for SOC sequestration is 0.146 MMTC yr^–1 for adopting conservation tillage, 0.011–0.035 MMTC yr^–1 for crop residue management, 0.026 MMTC yr^–1 for judicious use of mineral fertilizer, 0.016–0.135 MMTC yr^–1 for manure application, and 0.036 MMTC yr^–1 for adopting crop rotations. The overall potential of these practices for SOC sequestration ranges from 0.591 to 1.022 MMTC yr^–1 with an average value of 0.806 MMTC yr^–1. Of the total potential, 59% is due to adoption of erosion control measures, 5.8% to restoration of peat lands, 21% to conversion to conservation tillage and residue management, and 14% to adoption of improved cropping systems. Enhancing SOC sequestration and improving soil quality, through adoption of judicious land use and improved system of soil and crop management, are prudent strategies for sustainable management of soil, water and environment resources.Readers should send their comments on this paper to: bhaskarn ath@aol.com within 3 months of publication of this issue.     

柑橘果园扩张对寻乌水径流和输沙的影响

土地利用变化的水文效应是当前人类活动环境影响的研究热点.柑橘果园扩张是近20年来寻乌水流域最主要的土地利用变化.利用寻乌水流域3个时期的土地利用数据,设定不同土地利用情景,以SWAT模型模拟不同土地利用情景下的径流与输沙,并结合2000年以来柑橘果园扩张的遥感制图成果和寻乌水径流和泥沙观测资料,分析柑橘果园扩张对流域径流和输沙的影响.研究表明:SWAT模型模拟径流的效果较好(Re =-0.05;R2 = 0.79;Ens = 0.72),输沙模拟效果也在合理范围(Re = 0.75;R2 = 0.8;Ens = 0.71);1990～2015年间,寻乌水流域林地面积减少36.83％,果园面积增加42.48％,径流与输沙变化率分别为2.57％和4.27％;新垦果园面积与河道输沙量的关系不显著,这是因为河道输沙不仅与土壤侵蚀有关,同时也与土壤侵蚀地块与河道之间的区位关系有关,同时,在反坡水平阶等水保措施的作用下,果园水土流失得到有效控制.     

峡山地不同垂直带土壤层的水文功能及其影响因子

渗透性能和持水能力是土壤重要的水力学性质,是土壤调节径流、保持水土和涵养水源等水文功能的基础。以三峡库首的夷陵-大老岭山地为对象,采集亚高山棕壤针叶林地、中山黄棕壤针阔混交林与茶园地和低山黄壤针叶林地等4个样点剖面的土壤样品,在室内进行土壤饱和导水率、水分特征曲线和理化性质测定,量化了不同样地土壤渗透性能、持水能力和水分库容等水文功能参数,并明确了其主要影响因子。结果表明: 研究区山地土壤饱和导水率在0.06～14.78 mm/min之间,亚高山棕壤和中山黄棕壤林地土壤渗透性能较好,其平均饱和导水率在7.15～14.78 mm/ min之间,低山黄壤次之（1.3 9 mm/min）,中山黄棕壤茶园土壤渗透能力最差（1.17 mm/min）。不同类型土壤的饱和含水量、毛管含水量、田间持水量存在较大差异,凋萎含水量差异较小。同一类型土壤的不同发生层内,土壤饱和含水量随土壤深度的增加而递减,毛管持水量和田间持水量随土层深度的增加波动上升。不同样地间土壤水分总库容差异较大,随着海拔的升高,土壤水分总库容增加。土壤水分特征参数与土壤性质的相关分析表明,饱和导水率与土壤总孔隙度呈显著正相关,与容重呈显著负相关;饱和含水量、毛管持水量、田间持水量均与土壤总孔隙度、粘粒含量呈显著性正相关,与容重呈显著负相关;饱和含水量与根系重量呈显著正相关;毛管持水量、田间持水量与砂粒含量呈显著负相关。与中山茶园地和低山黄壤林地相比,亚高山棕壤和中山黄棕壤林地渗透性能较好且持水性更强,具有更好的调蓄径流和涵养水源的水文功能。 关键词： 山地土壤;土壤孔隙度;饱和导水率;持水能力;三峡库区     

Impacts of future land use/land cover on wildfire occurrence in the Madrid region (Spain)

This paper assesses the relative importance of socioeconomic factors linked to fire occurrence through the simulation of future land use/land cover (LULC) change scenarios in the Madrid region (Spain). This region is a clear example of the socioeconomic changes that have been occurring over recent decades in the European Mediterranean as well as their impact on LULC and fire occurrence. Using the LULC changes observed between 1990 and 2006 as a reference, future scenarios were run up to 2025 with the conversion of land use and its effects model. Simultaneously, the relationship between LULC arrangement (interfaces) and historical fire occurrence was calculated using logistic regression analysis and used to quantify changes in future fire occurrence due to projected changes in LULC interfaces. The results revealed that it is possible to explain the probability of fire occurrence using only variables obtained from LULC maps, although the explanatory power of the model is low. In this context, border areas between some LULC types are of particular interest (i.e., urban/forest, grassland/forest and agricultural/forest interfaces). Results indicated that expected LULC changes in Euro-Mediterranean regions, particularly given the foreseeable increase in the wildland–urban interface, will substantially increase fire occurrence (up to 155 %). This underlines the importance of future LULC scenarios when planning fire prevention measures.     

基于GIS和RUSLE模型的万州区土壤保持服务功能空间分布特征

土壤保持服务是重要的生态系统服务之一,代表生态系统对土壤侵蚀所起到的削减和改善作用。以万州为研究区,基于GIS平台和修正通用土壤流失方程(RUSLE),运用降雨、DEM等数据建模,探讨万州区土壤保持服务功能的空间分布特征并分析其影响因素。结果显示:(1)万州区土壤保持总量为1 435.84×10~5t/a,单位面积年均土壤保持量为417.91 t/(hm~2·a),具有较高的土壤保持服务功能重要性;(2)土壤保持服务空间分布受地形和人类活动等的显著影响,东南部山地区域较高,而铁峰山与方斗山之间的长江河谷较低,其空间分布特征与土壤侵蚀的分布状况大致相反;(3)坡度角度,15°~25°坡度区产沙量最大占全区的41.56%,8°~15°区域次之,这两个坡度区人地矛盾最为集中;土地利用类型中,旱地侵蚀最为强烈,而林地侵蚀微弱并表现出很高的土壤保持服务功能。研究结果对万州乃至整个三峡库区的水土保持工作有借鉴意义。