Field bioassessments for selecting test systems to evaluate military training lands in tallgrass prairie. Ecosystem health. V

Ecosystem responses to physical or chemical stress may vary from changes in single organisms to alteration of the structure and function of the ecosystem. These responses to stress cannol be predicted exactly. Ecosystems repeatedly exposed to physical and/or chemical stress can be used to study the separate and combined environmental effects of stress. Such studies also allow the development of procedures to select test systems for the analysis of stress in ecosystems. A preliminary field survey of six military training sites at Fort Riley, Kansas, USA, was conducted to identify and verify ecological test systems for evaluating ecosystem responses to physical and/or chemical stress. Comparisons of these data with data collected concurrently from Konza Prairie Research Natural Area reference sites showed that soil microarthropods, some species of macroarthropods, small mammals, and native earthworm species were negatively affected by stress. In contrast, plant species diversity, plant foliage biomass, soil mycorrhizae, and many soil characteristics were within the boundaries of nominal variations observed on “pristine” Konza Prairie. Introduced European earthworms appeared to be positively affected by training activities. This study provided a test of systematic procedures to support impact analysis, ecological toxicology, and ecosystem risk assessments. This is paper IX in D. J. Schaeffer's “Environmental Audit” series.     

南水北调中线丹江口库区水环境现状

从丹江口库区的自然、气候概况、水量状况、水环境现状、水土流失等方面对丹江V口水库进行了分析。目前丹江口水库水质现状不容乐观，主要问题有：水土流失严重，森林覆盖率低，工业、农业污染严重，城镇、农村生活污水和养殖污水等大量排放，造成丹江口水库水质呈现中一富营养，并向富营养转化的趋势。要改善水库的水质现状，对工业污染坚持“预防为主”的原则，优化产业结构，全面实施污染物总量控制制度；对城镇、农村生活污水排放，加强城镇基础设施建设，控制城镇生活污染，进行城市生态建设；对养殖污水排放，制定合理的养殖计划，实施生态养殖；对农业污染，在库区要大力推进自然保护区、生态示范区、生态功能保护区和环境保护的建设，以小流域综合治理为基础，全面改善生态与环境，全面保护南水北调中线水源地丹江口水库水质。     

Migratory orientation of red-eyed vireos,Vireo olivaceus,in relation to energetic condition and ecological context

How and when migrants integrate directional information from different sources may depend not only on the bird’s internal state, including fat stores, but also on the ecological context during passage. We designed experiments to (1) examine the influence of stored fat on the decision to migrate and on the choice of migratory direction and (2) investigate how the integration of orientation cue information is tied to energetic status in relation to migration across an ecological barrier. Migratory orientation of red-eyed vireos (Vireo olivaceus) at twilight was recorded using two different techniques, orientation cage experiments and free-flight release tests, during both fall and spring migration. During fall migration, the amount of stored fat proved decisive for directional selections of the vireos. Fat birds chose directions in accordance with migration across the Gulf of Mexico. Lean birds oriented either parallel to the coast line (cage tests) or moved inland (free-flight releases). Whereas only fat birds showed significant responses to experimental deflections of the geomagnetic field, lean birds displayed a tendency to shift their activity in the expected direction, making it difficult to evaluate the prediction that use of the magnetic compass is context dependent. Fat loads also had a significant effect on the decision to migrate, i.e., fat individuals were more likely to embark on migration than were lean birds (true for both cage and release experiments). During spring migration, a majority of experimental subjects were classified as lean, following their arrival after crossing the Gulf of Mexico, and oriented in seasonally appropriate directions. The vireos also showed significant responses to experimental deflections of the geomagnetic field regardless of their energetic status. Free-flight release experiments during spring migration revealed a significant difference in mean directions between clear sky and overcast tests. The difference may indicate a compensatory response to wind drift or possibly a need for celestial cues to calibrate the magnetic compass. Finally, this is the first demonstration of magnetic compass orientation in a North American vireo. Received: 15 December 1995/Accepted after revision: 24 March 1996     

白鱀豚种群现状、致危因素及保护策略的研究

受人类活动的影响，白鱀豚种群衰减速度加快。１９８６年种群数量不足３００头；１９９１年发现又有减少。致危原因是：受葛洲坝水利工程的影响，受裁弯工程影响，受江湖阻隔、江水污染、航船噪声、食物鱼减少等因素影响，白豚栖息活动的缓回水区环境恶化，严重干扰了白　豚的生存和繁衍。抢救白　豚首先要保护好白　豚赖以生存的缓回水区，减少意外死亡。继而活捕白　豚，将部分个体从长江干流移入人工饲养池、半自然水域或自然水域内进行养护繁殖，同时大力加强科学研究，提高保护效能。     

社会需要的两极保障与社会的稳定发展——关于灾害的若干社会学思考

本文从社会需要的两极保障是社会稳定与发展的前提出发,论述了社会需要、自然环境与灾害的关系;并从发展生产与引导人的需要两方面阐述了维护生态平衡是减灾工作的重点途径之一。     

长江上游地区土地沙漠化现状及其驱动力的研究

利用最新的土地沙漠化普查数据 ,分析了长江上游地区土地沙漠化的现状及主要危害 ,阐述了该区土地沙漠化的主要影响因素及其驱动力 ,并提出了其土地沙漠化防治的具体对策与措施。结果表明 ,长江上游地区共有沙漠化土地 60 .98× 10 4hm2 ,集中分布于长江源区 ;土地沙漠化类型包括流动沙 (丘 )地、半固定沙 (丘 )地、固定沙 (丘 )地和裸露沙砾地四种 ,其中裸露沙砾地是其主体 ;区内重度、中度与轻度沙漠化土地所占比例分别为 11.5 3 %、5 8.94 %和 2 9.5 3 % ,中度居多 ,沙漠化程度总体偏重 ;土地沙漠化主要造成草地退化、导致冻土退化、影响人类社会经济活动 ,并危及全流域及周边地区的生态环境保护与建设 ;该区土地沙漠化的发生与发展是自然因素与过程、人为因素与过程共同作用的结果 ,其中自然因素是其首要影响因素 ,气候变化是其主要驱动力     

基于供给—消耗关系的蒙古高原草地承载力时空变化分析

在全球气候变化与人类活动加剧的双重影响下,蒙古高原草地放牧超载与草地退化问题不断凸显。如何从畜牧业生产对草地利用强度角度揭示草地生态系统的人地关系,对草地资源可持续利用对策研究至关重要。基于生态系统供给与消耗平衡关系,利用卫星遥感数据与畜牧业统计数据,分析蒙古高原草地生态系统的生态承载状态,研究不同政策背景和资源禀赋条件下草地生态系统承载压力的区域差异特征。研究结果表明：（1）内蒙古自治区和蒙古国两地不同的政策和习俗深刻影响了牧民对草地的利用方式,使得两地畜牧业生产结构产生显著差异,内蒙古自治区牲畜类型组成区域差异性大、总量相对平稳,而蒙古国牲畜数量增加显著、牲畜类型组成区域分布更为均匀。（2）内蒙古自治区和蒙古国草地消耗量均呈现出明显的上升趋势,蒙古高原草地资源消耗总量在2014年超出了供给量,其中内蒙古自治区草地资源消耗量在2005年超出了供给量,而近年来蒙古国的草地资源消耗量也逐渐逼近供给量。（3）2000-2016年间,蒙古高原草地承载压力不断增大,整体从盈余状态变为临界超载状态,持续严重超载地区主要出现在荒漠草原地区,并逐渐向典型草原及农牧交错区推进;蒙古国自2003年起富富有余状态区逐步减少且严重超载区逐步增多,内蒙古自治区则受生态保护政策的影响呈波动性变化。通过定量分析内蒙古自治区和蒙古国草地承载状况的时空差异性,所揭示出的不同社会经济背景下畜牧业生产结构与强度的变化规律可为草地资源管理提供科学依据。     

2000年来中国生态状况时空变化格局

21世纪以来,我国在经济快速发展的同时高度重视生态环境保护,一系列生态修复工程和空间管控措施使生态状况发生了巨大变化;然而目前对于全国生态状况宏观格局的认识仍十分有限。借助 Google Earth Engine（GEE）遥感云计算平台,采用主成分分析方法和MODIS数据构建的绿度NDVI、热度LST、湿度WET和干度NDSI四个指标,生成长时间序列的遥感生态指数RSEI数据集,完整刻画了中国2000年来生态状况的时空连续变化格局。研究发现:在空间格局上,东南沿海地区生态状况优于西北地区;变化趋势上,全国生态状况除上海、西藏和澳门之外均显著改善,RSEI增长最多的三个省份为山西、陕西和河北。进一步采用遥感云计算定量评价了2000年来生态状况变化的宏观格局,以期为国土空间管控和生态保护提供科学支持。     

Profiles of and variations in aluminum species in PAC-MC used for the removal of blooming microalgae

Polyaluminum chloride modified clay (PAC-MC) is a safe and efficient red tide control agent that has been studied and applied worldwide. Although it is well known that the distribution of hydrolytic aluminum species in PAC affects its flocculation, little is known about the influence of particulars aluminum species on the microalgae removal efficiency of PAC-MC; this lack of knowledge creates a bottleneck in the development of more efficient MCs based on aluminum salts. The ferron method was used in this study to quantitatively analyze the distributions of and variations in different hydrolytic aluminum species during the process of microalgae removal by PAC-MC. The results showed that Al_a, which made up 5%–20% of the total aluminum, and Al_p, which made up 15%–55% of the total aluminum, significantly affected microalgae removal, with Pearson's correlation coefficients of 0.83 and 0.89, respectively. Most of the aluminum in the PAC-MC sank rapidly into the sediments, but the rate and velocity of settlement were affected by the dose of modified clay. The optimal dose of PAC-MC for precipitating microalgae was determined based on its aluminum profile. These results provide guidance for the precise application of PAC-MC in the control of harmful algal blooms.     

秸秆产生利用现状调查与禁烧面临难点分析——以江苏省某乡镇为例

以江苏省某乡镇为对象,开展了农作物秸秆产生量、秸秆利用状况、农民处理秸秆方式的调查研究。结果表明,秸秆收集利用量占秸秆产生总量的比例不足25％,50％以上农户产生的秸秆得不到有效利用;农业从业者综合素质相对较低、技术普及不到位、作物收种时间重叠、效益驱动不足、秸秆利用机制不健全是秸秆禁烧和利用面临的主要问题。针对主要问题,从科技支撑、有效组织、政策引导、农机农艺、宣传培训等方面提出了合理的建议。