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81.
北京翠湖湿地生境恢复及效果评估   总被引:1,自引:0,他引:1  
湿地恢复是指通过生态技术或生态工程对退化或消失的湿地进行修复或重建,再现退化前的结构和功能以及相关的物理、化学和生物学特性,使其发挥应有的作用。自2010年,翠湖湿地综合运用了微地形重塑、基质恢复、植被种植和岸带护坡等湿地生境恢复技术,累计应用面积约13.33 hm2。翠湖湿地应用生境恢复技术之后,有效改善了水环境质量,血红裸藻"水华"现象爆发频率显著降低,水华覆盖面积得到有效控制。同时,湿地基质质量得到了有效提升。湿地植被覆盖度由恢复之前的51%增加到恢复后的71%;植物物种由221种增加为236种;水鸟种类和偶见种有所增加。本研究可为城市湿地恢复提供技术支撑。  相似文献   
82.
The Phase 1 Survey is the most comprehensive and widely used national level map of semi-natural habitats in Wales. However, the survey was based largely on field survey and was conducted over several decades, before being completed in 1997. Given that resources for a repeat survey were limited, this study has used an object-orientated rule-based classification implemented within eCognition of multi-temporal satellite sensor data acquired between 2003 and 2006 to map semi-natural habitats and agricultural land across Wales, thereby allowing a progressive update of the Phase 1 Survey. The classification of objects to Phase 1 habitat classes was undertaken in two steps; firstly the landscape of Wales was divided into objects using orthorectified SPOT-5 High Resolution Geometric (HRG) reflectance data (10 m spatial resolution) and Land Parcel Information System (LPIS) boundaries. A rule-base was then developed to progressively discriminate and map the distribution of 105 sub-habitats across Wales based on time-series of SPOT HRG, Terra-1 Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Indian Remote Sensing Satellite (IRS) LISS-3 data, derived datasets (e.g., vegetation indices, fractional images) and ancillary information (e.g., topography). The rules coupled knowledge of ecology and the information content of these remote sensing data using a combination of thresholds, Boolean operations and fuzzy membership functions. A second rule-base was then developed to translate the more detailed sub-habitat classification to Phase 1 habitat classes. Indicative accuracies of the revised Phase 1 mapping, based on comparisons with the later Phase 2 survey (for selected habitats), were >80% overall and typically between 70% and 90% for many classes. Through this exercise, Wales has become the first country in Europe to produce a national map of habitats (as opposed to land cover) through object-orientated classification of satellite sensor data. Furthermore, the approach can be adapted to allow continual monitoring of the extent and condition of habitats and agricultural land.  相似文献   
83.
钟波 《地理空间信息》2011,(6):45-46,54
通过安装于粪渣收运车辆上的车载称重系统(WS)和全球卫星定位系统(GPS),经由通用无线分组业务(GPRS)将粪渣收运车载重变化及其位置信息,实时传回监控中心的数据库中[1],并通过集成地理信息系统(GIS)的粪渣收运监控系统浏览、查询、管理粪渣收运情况。主要以车载重量变化信息作为收运监控参考的重要依据,并配合车辆定位...  相似文献   
84.
Juvenile north-temperate and Arctic fishes are faced with trade-offs between energy allocation to growth and energy storage (primarily lipids) prior to over-wintering. We determined classical morphometric (fork length, body weight and condition factor) and biochemical (whole body triglycerides, muscle RNA/DNA ratio, muscle proteins) measures of growth and condition in individual young-of-the-year (YOY) Arctic grayling (Thymallus arcticus). Grayling were collected just prior to over-wintering in late August (approximately 50 days after swim-up) from two natural streams and five locations within a 3.4 km long artificial stream constructed as a fish habitat compensation project and diversion channel for the diamond mining industry in Northwest Territories, Canada (64°45′N). Fork lengths, body weights and whole body triglyceride levels in grayling collected from all sites along the artificial stream were significantly lower than fish collected from one of the natural streams. Condition factor (weight-at-length) was not different among grayling collected from natural and artificial streams. Muscle proteins were lower in grayling collected from four sites along the artificial stream compared to the natural streams. In contrast, muscle RNA/DNA ratios were greater in grayling collected from two sites in the artificial stream compared to natural streams. There were no consistent differences in any variable among grayling collected at the five artificial stream sites or among grayling collected from the two natural streams. The higher RNA/DNA ratios and lower fork lengths, whole body triglycerides and muscle proteins in grayling inhabiting the artificial stream are consistent with energy still being primarily allocated to growth in these fish at this late stage of summer. Individuals that are both larger and possess greater energy storage in the form of triglycerides are more likely to survive the long over-wintering period at this latitude. Our results suggest that YOY grayling using the artificial stream as nursery habitat will likely face increased over-winter mortality, thus raising concerns over the use of fish presence, spawning and rearing as criteria for the initial success of artificial streams as habitat compensation measures in Arctic tundra regions. Further research is needed to determine the potential consequences of reduced size and energy storage in juvenile fishes in order to assess the viability of stream fish habitat compensation and restoration projects associated with industrial development in Arctic tundra regions.  相似文献   
85.
86.
Although many species in the pelagic ocean are widespread, they are not randomly distributed. These species may have associations with particular water masses or habitats, but to best understand patterns in the ocean, these habitats must be identified. Previous efforts have produced static or seasonal climatologies, which still represent smearing over habitats. The Eastern Tuna and Billfish Longline Fishery (ETBF) targets a range of high trophic level species in oceanic waters off eastern Australia. In this study, dynamic ocean habitats in the region were identified for each month based on cluster analysis of five oceanographic variables averaged at a monthly time scale and a spatial scale of 0.5° for the period 1995-2006. A total of seven persistent habitats were identified off eastern Australia with intra and interannual variation in size and location, indicating the importance of spatial and temporal variation in the dynamics of the region. The degree to which these dynamic habitats were distinguished was tested using (i) stable isotope analysis of top fish predators caught in the region and (ii) estimates of variation in estimated abundance generated from catch data from the fishery. More precise estimates (measured as lower total CV) of isotopic values from swordfish (Xiphias gladius), yellowfin tuna (Thunnus albacares) and albacore (Thunnus alalunga) were obtained for 4 of 6 isotope comparisons using the dynamic habitat groupings, which indicate that stratifying by pelagic habitat improved precision. Dynamic habitats produced more precise abundance estimates for 7 of 8 large pelagic species examined, with an average reduction in total CV of 19% compared to when abundance was estimated based on static habitat stratification. These findings could be used to guide development of effective monitoring strategies that can distinguish patterns due to environmental variation, and in the longer term, climate change.  相似文献   
87.
设计基于DTU的强振记录终端,采用SOC系列C8051F015型单片机对MEMS加速度计的输出信号进行A/D转换,监测待测体所经受的强振加速度值,并通过DTU内嵌的GPRS无线网络通讯方式将数据发送到远程数据中心.该系统具有体积小,安装与操作方便,免维护等特性.  相似文献   
88.
We conducted a manipulative experiment to investigate the influential factors of locomotor ability in steppe toad-headed lizards. By using a video-base method, we measured running speed of the lizards when they run on sands of different grain sizes. We also considered body condition, tail length and sex as fixed factors to analyze their effects on running speed of the lizard. Results showed that running speed of the lizard significantly differed among different trials of sand grain size. Specifically, the peak and the nadir values of the running speed were found on sands of 0.5-1 mm and 0.075-0.25 mm grains, respectively. When lizards ran on sands of different grain size their running speed changed significantly. Body condition and tail length also had significant effects on running speed. The findings indicated that locomotor ability of lizards depended on both body condition and the external environment. We hypothesized that sand grain size is one of the factors that influence the habitat selection in steppe toad-headed lizards. Moreover, this lizard may be used as an indicator of the development of sand dunes.  相似文献   
89.
地震叠前时间偏移的一种图形处理器提速实现方法   总被引:25,自引:11,他引:14       下载免费PDF全文
新近发展的图形处理器(GPU,Graphic Processing Unit)通用计算技术,现已日趋实用成型,并获得诸多应用领域的广泛关注.对油气勘探专项资料处理技术的运用而言,概因GPU与中央处理器(CPU)的计算性能的甚大差异,致使GPU这一通用计算技术在石油工业中的应用研究正在有效开展.本文仅借助于油气勘探中广泛使用的叠前时间偏移,旨在于扼要阐明其基于GPU应用的有效性;文中还提出一种利用GPU实现地震叠前时间偏移的软件构件方法,并针对非对称走时叠前时间偏移所拓展的应用软件提供一种具体实现架构.与以往用个人计算机(PC,Personal Computer)或者PC集群所用的叠前时间偏移相比,本文方法可甚大地提高计算效率,从而在石油物探资料处理中可显著地节约计算成本和维护费用.文中实际例证也表明,基于GPU进行高性能并行计算,当是适应目前石油工业中大规模计算需求的一个重要发展途径.  相似文献   
90.
1999年 7月 19~ 3 0日 ,第 2 2届 IUGG大会在英国伯明翰大学举行。从提交的论文中可以看出 ,有关地震预测和地震灾害的研究仍是地学界关注的热点问题。文章介绍了这次大会反映出的有关地震预测研究的情况。  相似文献   
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