对生态环境可持续发展的一些思考——以陕西岚皋县岚河开发为例     

张军 《南方国土资源》2010,(3):27-28

陕西岚皋县曾经是个山清水秀的地方,因为建设多个水电站,当地的生态环境遭到了一定程度的破坏。笔者以岚皋县岚河开发为例,对我国现在过度开发水资源的现状进行了反思,并提出了实现可持续发展的一些建议,从而呼吁加快水资源法制建设的步伐,保护生态环境。  相似文献   

Impacts of solar UV radiation on grazing, lipids oxidation and survival of Acartia pacifica Steuer (Copepod)     

MA Zengling  LI Wei  GAO Kunshan 《海洋学报(英文版)》2012,31(5):126-134

UV radiation is known to affect aquatic primary producers and their grazers. However, little has been documented on its effects on zooplankton grazing. In this study, the authors investigated the effects of photosynthetically active radiation (PAR, 400-700 nm), ultraviolet-A (UV-A, 320-400 nm) and ultraviolet-B (UV-B, 280-320 nm) radiation on grazing, mortality and lipids oxidation of the copepod Acartia pacifica collected from the Xiamen Bay. After 30 min of the exposures, the copepod was fed in darkness with the diatom Phaeodactylum tricornutum at two cell concentrations (2.5 × 10 4 and 2.5 × 10 5 cells/ml). At the low cell concentration, the individuals pre-exposed to PAR (218.0 W/m 2 )+UV-A (48.2 W/m 2 ) or PAR+UV-A+UV-B (2.1 W/m 2 ) showed suppressed clearance and grazing activities compared with those receiving PAR alone, by 22.7% and 17.1% for clearance and by 22.6% and 5.5% for grazing rates, respectively. However, the suppression on clearance and grazing became indistinctive at the high food concentration. Exposures to UV-A and UV-B led to increased lipid oxidation and higher mortality, furthermore, the mortality linearly increased with enhanced oxidation of lipid.  相似文献   

Vegetation and Community Changes of Elm （Ulmuspumila） Woodlands in Northeastern China in 1983-2011     

Li Liu  He Wang  Changcun Lin  Deli Wang 《中国地理科学(英文版)》2013,23(3):321-330

Elm (Ulmus pumila), widely distributed in the north temperate zone, contributes to a special savanna-like woodland in typical grassland region in the northeastern China. This woodland performs a variety of ecological functions and environmental significance, such as decreasing soil erosion, stabilizing sand dunes, preserving species diversity. However, in the last approximate 30 years, the species composition, productivity and distribution area of elm woodland has decreased severely. A series of studies have been carried out to find out whether the climate changes or human disturbances caused the degradation of elm woodland and how these factors affected elm woodland. In this study, undisturbed, plowing and grazing elm woodland were investigated in 1983 and 2011 by using Point-Centered Quarter method. The relationship between vegetation changes and environmental factors was analyzed by Bray-Curtis ordination. The results show that in 2011, species diversity and understory productivity of undisturbed elm woodland decrease slightly compared to those of undisturbed elm woodland in 1983. However, nearly 60% of the species is lost in the plowing and grazing elm woodland relative to the species undisturbed elm woodland in 1983. Interestingly, plowing stimulates the growth of elm and certain understory species through furrowing soil and accelerating soil nutrient turnover rate. Grazing disturbance not only leads to species loss and productivity decrease, but also induces changes in elm growth (small, short and twisted). The mean age of the elm was 29 ± 2 yr in undisturbed and plowing elm woodland, while only 15 yr in the grazing elm woodland. The results of Bray-Curtis ordination analysis show that all sample stands clustered to three groups: Group I including the undisturbed sample stands of 83UE (undisturbed elm woodland in 1983) and 11UE (undisturbed elm woodland in 2011); Group II including sample stands of PE (elm woodland disturbed by plowing); Group III including samples stands of GE (elm woodland disturbed by grazing). The results indicate that the long time disturbance of the plowing and grazing have converted elm woodland to different community types. Climate change is not the primary reason causing the degradation of elm woodland, but plowing and grazing disturbance. Both plowing and grazing decrease the vegetation composition and species diversity. Grazing further decreases vegetation productivity and inhibits the growth of elm tree. Therefore, we suggest that reasonable plowing and exclusive grazing would be favorable for future regeneration of degraded elm woodland.  相似文献   

放牧梯度上草原植被土壤系统碳截存特征     

张雪  乌云娜  林璐  赵晨羽  王雪婷  白佳忆 《中国沙漠》2013,33(6):1789-1795

放牧强度影响草原植被的固碳能力。本文以呼伦贝尔克鲁伦河流域的半干旱典型草原作为研究区域,开展不同放牧压力下异质性植被-土壤系统中碳截存的特征研究。研究发现:不同放牧梯度下,土壤有机质、地上生物量、地下生物量和土壤微生物生物量碳彼此之间呈一定的相关性。随着放牧强度的加剧及土层深度的加深,土壤碳截存量呈减少趋势。其中,土壤有机质的变化趋势与土壤碳截存量趋势相同;而土壤无机碳含量呈现逐渐增大的特征。过度放牧破坏了土壤的理化性质及土壤质量,加速了土壤有机质的损失。草原群落的根冠比也随着放牧强度的增大而增加。以土壤微生物生物量碳作为土壤固碳能力的指标,不同放牧强度下的草原群落土壤固碳能力为轻牧区>中牧区>重牧区。  相似文献   

保护优势矿种 严格总量管控——《开采总量控制矿种指标管理暂行办法》解读     

丁全利 《国土资源通讯》2012,(7):21

近日,国土资源部出台《开采总量控制矿种指标管理暂行办法》,在矿产资源管理上推出了新的管理目标、措施。为此,记者采访了部矿产开发管理司负责人,对此《办法》进行解读。保护优势矿种,防止过度开采  相似文献   

藏北高原高寒草地围栏禁牧和生长季降水对物种丰富度和多样性的影响(英文)   总被引：2，自引：2，他引：0  

武建双  张宪洲  沈振西  石培礼  余成群  宋明华  李晓佳 《资源与生态学报(英文版)》2012,(3):236-242

2009和2010年夏天沿藏北高原高寒草地样带调查了高寒草地生态系统(高寒草甸、高寒草原和荒漠草原)在围栏禁牧和自由放牧管理下的物种丰富度和多样性(Shannon-Wiener指数,Simpson优势度指数和Pielou均匀度指数)。研究结果显示:自2006年起藏北高原围栏禁牧在植被类型和区域尺度上没有显著改变物种丰富度和多样性。物种丰富度和多样性主要受生长季降水驱动,超过87%的变异可由生长季降水来解释。物种丰富度和多样性在自由放牧和围栏禁牧2类样地对生长季降水的响应方式一致。物种丰富度随降水呈指数型增长关系,多样性指数则呈现正线性关系。研究结果预示藏北高原地区生长季降水的变化对于物种丰富度和多样性管理至关重要,在未来高寒草地保护研究中应予以重视。  相似文献   

赵如龙:开拓市场加强与国际接轨     

赵如龙 《中国勘察设计》2005,(5):14-14

当前，我国正朝着知识化、信息化社会迈进，同时，经济全球化趋势的加速以及我国加入WTO过渡期的结束，使工程咨询和勘察设计行业面临的市场环境、人才环境、政策环境都发生了深刎的变化。由此，工程咨询和勘察设计市场结构和市场竞争方式将发生变化，过去的市场竞争目标趋同、同一市场过度竞争的情况逐步打破，多领域、多层次的市场结构和在多领域、不同层次市场卜技术能力与特色竞争的格局逐步形成。  相似文献   

放牧和围封下霸王灌丛对土壤肥力的影响   总被引：10，自引：12，他引：10  

裴世芳  傅华  陈亚明  李景斌 《中国沙漠》2004,24(6):763-767

对阿拉善退化荒漠草地恢复过程中霸王灌丛对土壤肥力的影响进行了研究。结果显示:(1)霸王灌丛对土壤的C、N、P有明显的富集,灌丛下的影响主要发生在0～10cm土层,而灌丛根部对10～20cm的土层也有影响。(2)放牧和围封显著影响着霸王灌丛根部和灌丛下的土壤肥力,土壤有机C、全N、全P均为围封6a>围封2a>自由放牧,pH值为围封6a<围封2a<自由放牧;放牧和围封也显著影响着灌丛根部和灌丛下的土壤养分富集率,土壤有机C、全N、全P的富集率均为围封6a>围封2a>自由放牧。(3)霸王灌丛生物量与灌丛根部、灌丛下土壤有机C、全N和全P的含量呈显著的正相关,与pH值呈显著的负相关,而与灌丛间地的土壤有机C、全N、全P和pH值没有明显的相关关系。  相似文献   

沙特阿拉伯地下水资源过度利用的后果及对策     

温金祥  崔华 《山东气象》2004,24(4):29-30

沙特阿拉伯位于阿拉伯半岛，总面积224万km^2，降水量很少且没有湖泊、河流，因此水资源十分匮乏，80％～85％的水资源为地下水。由于地表水资源的日益缺乏以及对水资源需求的逐年增加，沙特加大了对地下水的利用，约75％～85％的工农业及生活用水来自地下水，每年抽取的地下水远远超过其自然补给量，由于过度开采引发了一些严重的问题，如深层水的耗竭和地下水水质恶化。本文讨论地下水耗竭而产生的经济影响，并提出保护地下水资源的对策。  相似文献   

自检校平差中过度参数化的克服     

李德仁 《武汉大学学报(信息科学版)》1986,(3)

带附加参数的自检校平差是当今解析空中三角测量中补偿系统误差的最有效方法。可惜的是,当采用一个十分庞大的附加参数组时,在某些几何条件下将导致很坏的法方程系状态,从而使测求的平差结果很差。本文研究和试验了几种克服过度参数化的方法。它们不是用统计分析方法来消除某些附加参数的,因为这会引起实际计算的困难。本试验研究表明: ——如果采用飞行方向交叉的双区域,用自由附加参数平差,附加参数的可测定性和系统的可靠性均是可接受的; ——如果附加参数作为带权观测值,而且按信噪比确定其权,在许多情况下过度参数化将是可避免的。——如果所有的未知数按极大验后估计原理或岭估计原理处理成带权观测值,並给予一个小权(例如P=0.005～0.001),则在所试验的任何情况下均可克服过度参数化。  相似文献