川西北高寒草地沙化土壤特征及治理模式探讨——以阿坝州红原县为例

通过对川西北高寒草地不同类型的沙化样地0—10cm,10～20cm和20～30cm土壤有机质、pH和含水量进行分析。结果表明：（1）随着沙化程度加重,土壤有机质含量和土壤含水量明显降低;（2）随着土层深度增加,土壤有机质含量降低;未沙化、轻度沙化样地的土壤含水量随土层深度增加而降低,重度沙化样地则相反;（3）中度和重度沙化样地土壤pH约7．0,未沙化和轻度沙化pH值在6．5左右;沙地土壤有机质与pH值呈显著负相关关系,沙化土壤有机碳与水分损失是一个正反馈。鉴于川西高寒草地特殊环境,探讨了选用适宜的多年生高原药用植物或者其他高价值资源植物作为固沙材料,将治沙与经济发展相结合,建立高寒沙化草地治理模式。     

湟水河流域气候变化特征及其影响

文章利用1961-2005湟水河流域9个气象台站气温、降水等地面观测资料,研究了湟水河流域气候变化及其对农业的影响。结果表明：湟水河流域2001—2005年比最冷的60年代四季平均气温分别偏高0．7-2．5℃,冬季增温比较显著;年降水量总体变化趋势是中游地区缓慢增加,而上游和下游地区则缓慢减少,流域内年平均降水量呈减少趋势;四季地表蒸发量均在增加,夏秋季大于其它季节;90年代湟水河流域秋季和春季降水的减少,使得秋季和春季发生中（重）干旱的频次明显增加。     

从化市土地利用总体规划实施的生态效应评价

从生态系统服务价值的角度对从化市土地利用总体规划（1997-2010年）实施的生态效应进行了定量评价。结果表明,1996-2005年从化市土地利用变化的总体趋势是耕地、林地、牧草地和未利用地面积在减少,园地、建设用地和水域面积在增加;从化市生态系统服务总价值增加了0．0690亿元,增加率为0．21％。从化市土地利用总体规划（1997-2010年）基本可行,其实施虽然取得了一定的生态效应,但与规划预期目标相比尚有一段差距。     

玛纳斯县新湖农场植物治沙效益评估

利用新湖农场1998—2007年气象、社会、经济资料及实测植被、土壤数据,分析了近10年来防沙治沙情况,并选取定量、定性指标,建立效益评估模型,对植物治沙产生效益进行评估。结果表明：植被覆盖率由1990年1．63％提高到2007年5．37％,植物种类、土壤碱解N、速效P随栽植年限增加而上升,沙化面积比例由1990年的2．90％减少到2006年的0．59％,风沙天气由1998年的27次减少到2007年的4次;农场土地利用结构得到优化,人均林草面积由1990年人均0．02hm2增加到2006年0．15hm2。     

新疆和田—若羌地区土地荒漠化评价

基于Landsat TM/ETM和OLI卫星遥感数据,应用植被覆盖率法,对新疆和田—若羌地区的土地荒漠化进行了评价,并分析其影响因素。结果表明:1985-2015年,研究区重度荒漠化、中度荒漠化区域面积呈减小趋势;而轻度荒漠化、非荒漠化区域面积则呈增加趋势。研究区荒漠化的趋势变化与沙地戈壁以及耕地面积的变化密切相关,和田—若羌地区沙地戈壁面积在30年间减小4.19×105hm2,总体下降率为23.3%;而耕地面积则增加了1.03×105hm2,增加率为2.6%。     

持之以恒做好水污染防治工作，保障饮用水源地环境质量

中国环境监测总站数据汇总分析结果显示：2008年我国环境质量状况呈现改善趋势。2008年,全国地表水环境质量总体为中度污染;746个地表水国控监测断面中,Ⅰ～Ⅲ类水质比例为427％,较2007年提高了4．2个百允点;劣Ⅴ类水质断面比例为23．1％,较2007年下降了3,0个百分点,整体呈好转趋势。207个“十一五”总量削减目标责任书确定的水质目标考核断面中,148个达到2010年要求,占71．5％;59个未达到2010年要求,占28．5％。从目前全国环境质量状况变化趋势看,全国地表水劣Ⅴ类水质断面比例与“十一五”规划目标要求尚差1．1个百分点。七大水系国控监测断面Ⅰ～Ⅲ类水质断面比例已达到“十一五”规划目标要求。     

辽宁省沙化土地现状及防治措施

辽宁省沙化土地面积54.96×104hm2,潜在沙化土地面积60.66×104hm2.大部分的沙化土地分布在辽西北地区,辽西北是我国北方土地沙漠化最严重的地区之一.近来监测数据表明,辽宁省土地沙化有恶化的趋势,而且这种沙漠化正逐年向辽宁省的腹地扩展.根据辽宁省的沙化特点以及主要的生态环境问题,初步探讨了其有效的防治对策.     

基于3S技术的庄河市滨海湿地景观格局演变研究

庄河市位于黄海北部沿海地区,自然海岸线长达285km,拥有丰富的滨海湿地资源,对区域经济的发展具有显著的促进作用.以庄河市2000年和2010年的Landsat TM（或ETM）遥感影像获取研究区的滨海湿地斑块图形数据,选用生态意义较明确的景观特征指数,对庄河市滨海湿地的景观格局变化进行研究.研究结果表明,2000-2010年,庄河市滨海湿地总面积不断缩减,由2000年的131252.60hm2减少到2010年的121489.16hm2,减少幅度为7.44％;湿地斑块数不断增加,由2000年的3425块增加到2010年的3563块;湿地景观多样性指数（H）和景观形状指数（LSI）呈增加趋势,分别由2000年的0.6315和14.0分别增加到2010年的0.8554和18.7;景观优势度指数呈下降趋势,由2000年的0.8359下降到2010年的0.7364,表明庄河市滨海湿地的景观破碎化程度越来越严重.     

基于多源遥感数据的湟水流域河谷区裸地监测

摘要：2013年8月,为全面掌握湟水流域河符区的开发建设活动情况,采用印度IRS—P5、法国Spot6、美国快鸟和同产资源02C等多源遥感数据对湟水流域河谷区的裸地状况进行监测,建立了基于多源遥感数据的监测技术流程。结果表明：2012年冬季,湟源一乐都段裸地威块数为848块,面积为60．4888km2,与2011年冬季相比,斑块数增加了173块,面积增加了21．8891km2;2013年夏季,海晏一民和段裸地斑块数为1078块,面积为76．5562km2,与2012年冬季相比,斑块数增加了111块,面积增加了11．12km2,表明湟水流域河符区开发建设活动不断在增加。通过此次监测表明：基于多源遥感数据的凋佥方法是监测城市土地开发利用的有效手段。     

宁波市鄞州区农业土壤重金属含量变化及评价

为发展无公害农产品基地提供科学依据,2005年对浙江省宁波市鄞州区100个农业土壤样品中重金属含量进行了测定和评价。结果表明：耕层全砷、镉、铬、汞和铅的平均含量分别为8．1mg·kg^-1,0．163mg·kg^-1、100．1mg·kg^-1、0．257mg·kg^-1和3．6mg·kg^-1,与1983年宁波市的耕层土壤背景值相比,分别增加了12．5％、32．5％、61．2％、0．8％和55．2％,土壤已受到镉、铅和汞的轻微污染,而汞的污染已得到遏制。从总体上来说,鄞州区农业土壤环境质量良好,区内有98个点（占总样点数的98％）符合无公害农产品产地土壤环境质量要求,但有2个点（占总样点数的2％）分别受到镉和汞的污染。     

Analysis of Spatial and Temporal Evolution of Vegetation Cover in the Spanish Central Pyrenees: Role of Human Management

A vegetation cover increase has been identified at global scales using satellite images and vegetation indices. This fact is usually explained by global climatic change processes such as CO₂ and temperature increases. Nevertheless, although these causes can be important, the role of socioeconomic transformations must be considered in some places, since in several areas of Northern Hemisphere an important change in management practices has been detected. Rural depopulation and land abandonment have reactivated the natural vegetation regeneration processes. This work analyses the vegetation evolution in the central Spanish Pyrenees from 1982 to 2000. The analysis has been done by using calibrated-NDVI temporal series from NOAA-AVHRR images. A positive and significant trend in NDVI data has been identified from 1982 to 2000 coinciding with a temperature increase in the study area. However, the spatial differences in magnitude and the sign of NDVI trends are significant. The role of land management changes in the 20th century is considered as a hypothesis to explain the spatial differences in NDVI trends. The role of land-cover and human land-uses on this process has been analyzed. The highest increment of NDVI is detected in lands affected by abandonment and human extensification. The importance of management changes in vegetation growth is discussed, and we indicate that although climate has great importance in vegetal evolution, land-management changes can not be neglected in our study area.     

基于RS和GIS技术的重庆市主城区扩展分析

采用重庆市主城区2000年和2010年两个时相的TM影像提取城市扩展信息,对影像数据的归一化建筑指数（NDBI）、归一化植被指数（NDVI）和归一化水体指数（NDWI）进行RGB组合增强,再进行决策树分类和减法运算获取研究区扩展信息,发现建筑区面积增加了1.62倍,大部分是由植被区转变而来。其扩张方向受地理影响,南北方向为外延型,东西方向为飞地型。借助统计资料进行精度验证和城市扩展的驱动因素分析发现,区域发展政策、经济增长和人口扩张是主要的影响因素,探讨了对经济增长、城市扩张和人口增长的关系。研究结果表明,以遥感手段监测与研究城市发展变化的趋势是可行和高效的。     

昆山市农产品产地环境质量监测与评价

为研究昆山市农产品产地环境质量,采用采样分析方法,对昆山市农产品产地的代表性土壤、灌溉水、渔业水质量进行了定点取样分析检测,在此基础上依据国家相关环境质量标准进行了单因子污染指数法和综合污染指数法评价。结果表明,该市58.1%的耕层土壤为安全、清洁,36.6%的耕层土壤处于警戒限,为尚清洁,3.8%的耕层土壤为轻污染,1.5%的耕层土壤为中污染;76.0%的灌溉水为安全、清洁,24.0%的灌溉水处于警戒限,为尚清洁;73.5%的渔业水为安全、清洁,23.5%的渔业水处于警戒限,为尚清洁,3%的渔业水为轻污染。     

Land Surface Phenology and Land Surface Temperature Changes Along an Urban–Rural Gradient in Yangtze River Delta, China

Using SPOT/VGT NDVI time series images (2002–2009) and MODIS/LST images (2002–2009) smoothed by a Savitzky–Golay filter, the land surface phenology (LSP) and land surface temperature (LST), respectively, are extracted for six cities in the Yangtze River Delta, China, including Shanghai, Hangzhou, Nanjing, Changzhou, Wuxi, and Suzhou. The trends of the averaged LSP and LST are analyzed, and the relationship between these values is revealed along the urban–rural gradient. The results show that urbanization advances the start of the growing season, postpones the end of the growing season, prolongs the growing season length (GSL), and reduces the difference between maximal NDVI and minimal NDVI in a year (NDVI_amp). More obvious changes occur in surface vegetation phenology as the urbanized area is approached. The LST drops monotonously and logarithmically along the urban–rural gradient. Urbanization generally affects the LSP of the surrounding vegetation within 6 km to the urban edge. Except for GSL, the difference in the LSP between urban and rural areas has a significant logarithmic relationship with the distance to the urban edge. In addition, there is a very strong linear relationship between the LSP and the LST along the urban–rural gradient, especially within 6 km to the urban edge. The correlations between LSP and gross domestic product and population density reveal that human activities have considerable influence on the land surface vegetation growth.     

The Vegetation Coverage Dynamic Coupling with Climatic Factors in Northeast China Transect

Based on SPOT-VGT images and meteorological data, this paper applied an integrated method to investigate the vegetation dynamic and its response to climate factors during 1998-2008 in Northeast China Transect, one of 15 ecological transects listed in the International Geosphere-Biosphere Programme. The main findings are as follows: (1) The NDVI time series presented nonlinear patterns that vary with timescales. The series fluctuated greatly at the smallest timescale (20?days), showing no salient trend, whereas a trend manifested itself more and more with the increase of time scale and finally stabilized at the 320-day scale. Little difference was found between vegetation types about the NDVI periodicity, as they occurred on either a 280-day or a 290-day cycle. (2) NDVI exhibited a significant correlation with temperature, precipitation, and sunshine hours. Overall, the correlation between NDVI and temperature was the highest, followed by precipitation, sunshine hours, and relative humidity. For different vegetation types, the correlations between NDVI and climate variables diversified, increasing from desert steppe to typical steppe, meadow steppe, and forest. (3) The periodicity of temperature and precipitation occurred in either a 280-day or 290-day cycle, which was approximately coincident with that of NDVI. This further supported the significant relationship between NDVI and these two climate factors. (4) At all the time scales under examination, NDVI and temperature and precipitation are significantly, positively correlated, especially at the 160-day scale, which can be regarded as the most suitable time scale for investigating the responses of vegetation dynamics to climate factors at most stations.     

Watershed Evapotranspiration Increased due to Changes in Vegetation Composition and Structure Under a Subtropical Climate1

Abstract: Natural forests in southern China have been severely logged due to high human demand for timber, food, and fuels during the past century, but are recovering in the past decade. The objective of this study was to investigate how vegetation cover changes in composition and structure affected the water budgets of a 9.6‐km² Dakeng watershed located in a humid subtropical mountainous region in southern China. We analyzed 27 years (i.e., 1967‐1993) of streamflow and climate data and associated vegetation cover change in the watershed. Land use/land cover census and Normalized Difference of Vegetation Index (NDVI) data derived from remote sensing were used to construct historic land cover change patterns. We found that over the period of record, annual streamflow (Q) and runoff/precipitation ratio did not change significantly, nor did the climatic variables, including air temperature, Hamon’s potential evapotranspiration (ET), pan evaporation, sunshine hours, and radiation. However, annual ET estimated as the differences between P and Q showed a statistically significant increasing trend. Overall, the NDVI of the watershed had a significant increasing trend in the peak spring growing season. This study concluded that watershed ecosystem ET increased as the vegetation cover shifted from low stock forests to shrub and grasslands that had higher ET rates. A conceptual model was developed for the study watershed to describe the vegetation cover‐streamflow relationships during a 50‐year time frame. This paper highlighted the importance of eco‐physiologically based studies in understanding transitory, nonstationary effects of deforestation or forestation on watershed water balances.     

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.     

Hydrologic Effects of NDVI Time Series in a Context of Climatic Variability in an Upstream Catchment of the Minjiang River1

Abstract: Increasing regional vegetation activity has been frequently found especially in middle and high latitude and alpine areas, but the effects of which on regional hydrology is still highly uncertain. The Upstream Catchment of Minjiang River is a large mountainous catchment covering 22,919 km² with a diverse vegetation distribution pattern, including alpine group (A), subalpine group (SA), and temperate and subtropical group (T/ST). The Seasonal Mann‐Kendall test, a nonparametric trend test method, detected consistent upward trends in all groups in monthly accumulated growing degree days (AGDD_M) time series from 1982 to 2003, but no significant trend in mean monthly precipitation (MMP) time series in any group. The alpine group had a significant (p = 0.024) upward trend in monthly Normalized Difference of Vegetation Index (NDVI) time series from 1982 to 2003, in contrast, the SA and T/ST groups had decreasing (although not significant) trends. AGDD_M plays more important role than MMP in affecting NDVI change in alpine areas, indicating temperature was the main climatic driver. In contrast, water was the main driver for the T/ST group, as indicated by the significant correlation between NDVI and MMP and a weak correlation with AGDD_M. Correlation coefficients of NDVI and river flow varied with seasons, mostly negative, especially during the growing season (April to October). A significant (p = 0.025) correlation was found only in August, indicating that an increase in peak‐NDVI decreased high flow significantly. TI‐NDVI_c, which was developed in an attempt to track the vegetation change at the catchment scale, accounted for more than 40% of the evapotranspiration increase (r² = 0.43).