流域植被类型对洪水径流影响研究

流域中的植被类型对其水文响应过程有重要影响。现将分布式水文物理模型BTOPMC用于日本富士川流域,利用1993年9月的洪水资料,对不同种类植被的洪水径流过程进行了比较研究。计算结果表明,不同类型的植被对洪峰流量、洪峰时刻、涨水和退水速率都有一定的影响。     

水库库滨带植被配置模式及其生态效应研究

库滨带是水库生态系统与陆地生态系统进行物质、能量、信息交换的一个重要过渡带。作为水库边缘的一个缓冲地带,库滨带在涵养水源、保持水土和净化水质方面具有十分重要作用。目前,学术界对库滨带的研究多集中在大型水库,而数量众多的中小型水库往往是地方生产、生活用水的重要来源。因此,有必要对中小水库库滨带植被的配置模式和生态效应进行研究,提出中小型水库不同立地条件的适生树种和优化配置模式,从而提高其涵养水源、保持水土和净化水质的生态效应,以防止和减少中小水库的泥沙淤积,增强水库的供蓄水能力。     

USE OF NATIVE AND NONNATIVE NEST PLANTS BY RIPARIAN‐NESTING BIRDS ALONG TWO STREAMS IN NEW MEXICO

Nonnative plant invasions are a management concern, particularly in riparian forests, but little is known about mechanisms through which they influence vertebrate communities. In the American Southwest, native trees such as cottonwood (Populus spp.) are thought to provide better habitat for breeding birds than nonnative plants, which are more tolerant of human‐altered conditions. To evaluate effects of riparian forest composition on riparian‐nesting birds, we examined nest plant use along two rivers in New Mexico that differed in abundance of nonnative vegetation. Of the nests we observed, 49% along the Middle Rio Grande were constructed in nonnative plants, compared with 4% along the Gila River. Birds in the canopy and cavity‐nesting guilds constructed less than 5% of their nests in nonnative plants along either river. At the Middle Rio Grande, birds in the subcanopy/shrub guild constructed 67% of their nests in nonnative plants. Despite the relatively low availability of cottonwoods, they were used by greater numbers of species than any other woody plant at either river. Riparian obligates and species of conservation concern in the canopy and cavity guilds were especially dependent on cottonwood and Arizona sycamore (Platanus wrightii). Our results show that, although nonnative trees and shrubs support large numbers of nests for certain birds, cottonwoods and other large native trees are disproportionately important to riparian bird communities. Copyright © 2013 John Wiley & Sons, Ltd.     

Combined effects of coastal forest and sea embankment on reducing the washout region of houses in the Great East Japan tsunami

Coastal vegetation is widely recognized for its ability to reduce tsunami damage; however, coastal forests in large areas of the Tohoku and Kanto districts of Japan were destroyed by the Great East Japan tsunami on 11 March 2011. To elucidate the tsunami-mitigating effect of a coastal forest during a destructive tsunami, the combined effects of sea embankment and coastal forest were analyzed using post-tsunami survey data of the damage and a nonlinear long wave equation model that includes the breaking or washout condition of trees. The numerical simulations estimated that a 600-m-long coastal forest reduced the washout region of houses due to a 10-m-high tsunami at the coast by approximately 100 m, and the reduction achieved by a sea wall of approximately 5.4–6.4 m in height was approximately 560–1520 m. The height of a sea embankment or wall with sand dunes greatly affects the breaking condition of trees behind it by changing the tsunami flux overflowing the sea wall and the sand dune. For the combination of a sea embankment and a coastal forest during a destructive tsunami, the tsunami mitigation function of the coastal forest has an optimum value when the fluid force on the trees is strong but not strong enough to break the trees under the condition at which the tsunami overflows the sea embankment. At the investigated site, the effect of the coastal forest was larger than that of the sea embankment under optimal conditions. Thus, a coastal forest on a sand dune should be designed as a mitigation measure behind a sea embankment and optimally designed to protect the houses that are not protected from a tsunami by the sea embankment alone.     

Detection and monitoring of African vegetation fires using MSG-SEVIRI imagery

An operational procedure is presented that allows detecting active fires based on information from Meteosat-8/SEVIRI over Africa. The procedure takes advantage of the temporal resolution of SEVIRI (one image every 15 min), and relies on information from SEVIRI channels (namely 0.6, 0.8, 3.9, 10.8 and 12.0 µm) together with information on illumination angles. The method is based on heritage from contextual algorithms designed for polar, sun-synchronous instruments, namely NOAA/AVHRR and MODIS/TERRA-AQUA. A potential fire pixel is compared with the neighboring ones and the decision is made based on relative thresholds as derived from the pixels in the neighborhood.An overview is provided of results obtained for January and July 2007, respectively over Northern Africa (NAfr) and Southern Africa (SAfr), paying special attention to the spatial and temporal distribution of active fires. In both NAfr and SAfr, two types of vegetation clearly dominate in terms of fire activity, namely tree-covered areas, containing 40% of total fires observed, and shrub-covered areas, with 25% (19%) of total fires in NAfr (SAfr). However, marked differences were also to be found between the two regions; more than two-thirds (70%) of fires in SAfr were observed in land cover classes dominated by trees but the proportion is much lower (40%) in the case of NAfr. The duration of active fires in both regions tends to follow two-parameter generalized Pareto distributions, with both the scale and the shape parameters presenting very similar values for NAfr and SAfr.An assessment of the robustness of the algorithm, consistency of results and added value of the product was made by studying the daily cycle of fire activity over two regions located in northern and southern hemisphere Africa and by means of systematic comparisons against fire incidence reported in previous works and against hot spots extracted from the global daily active fire product developed by the MODIS Fire Team. The observed fire incidence by land cover class compares well with the results reported in previous works and it is shown that there is an overall coherence between results obtained from SEVIRI and MODIS when adequate spatial and temporal scales are chosen when performing the comparison. Data from MODIS and SEVIRI may be viewed as complementary, the latter having the added value of providing a much finer temporal resolution that allows uncovering certain aspects of fire behavior, namely the characterization of daily fire cycles.     

地域文化在住宅社区公共设施中的展示

文章对地域文化在住宅社区公共设施的现状,诠释了地域文化的作用与影响,并针对现状提出了在城市化后的住宅社区公共设施中的地域文化应有传承发展的看法。     

Response of montane meadow vegetation after two years of streamflow augmentation

Changes in montane meadow vegetation were examined in a previously ephemeral drainage that received flow augmentation as a mitigation measure for a transbasin diversion in southeastern Wyoming. After two years of elevated surface and groundwater levels, the herbaceous vegetation shifted toward more water-tolerant species. Dry meadows became like moist meadows, moist meadows became more like moist-wet meadows, and moist-wet meadows became more like wet meadows. Sedge (Carex spp.) biomass increased from 337 to 456 g m^?2 in the wet meadows, while tufted hairgrass (Deschampsia cespitosa) biomass decreased from 18 to 3 g m^?2 in the moist-wet meadows. Slimstem reedgrass (Calamagrostis neglecta) remained unchanged in the meadows with shallow standing water, but increased from 17 to 88 stems m^?2 in the dry meadows with an elevated water table. Bare ground also increased as much as 31 per cent in the meadows without a defined drainage channel.     

多沙粗沙区林草植被建设对径流影响初析

依据以往的研究成果,针对多沙粗沙区北部、中部和西南部的实际情况,采用综合分析和统计的方法,在确定林草植被蒸散耗水量基础上,应用与坡地蒸散耗水量相对比的方法,分析了林草植被建设对径流量的影响。结果表明:①对于灌木草地来说,整个多沙粗沙区都能够满足其对水分的需求,而乔木林地在北部区基本上不能满足其需要。②林草植被蒸散耗水量的区域分布,与最大可能蒸发量的分布大体相似,而与降水量分布呈相反趋势,呈现出由西北向东南部递减以及自西向东减少的趋势;北部较中部乔灌草植被分别约偏多8%、10%和17%,而西南部较中部乔灌林地和人工草地分别偏多3%左右和约6%。③从水资源的适应性来说,多沙粗沙区适应乔木生长的区域还是有一定的限制。     

Are animals stuck in time?

People can time travel cognitively because they can remember events having occurred at particular times in the past (episodic memory) and because they can anticipate new events occurring at particular times in the future. The ability to assign points in time to events arises from human development of a sense of time and its accompanying time-keeping technology. The hypothesis is advanced that animals are cognitively stuck in time; that is, they have no sense of time and thus have no episodic memory or ability to anticipate long-range future events. Research on animals' abilities to detect time of day, track short time intervals, remember the order of a sequence of events, and anticipate future events is considered, and it is concluded that the stuck-in-time hypothesis is largely supported by the current evidence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Decision-making in Water Management under Uncertainty

Decision-making in water management requires the delivery of accurate scientific information. However, the task is challenging under the situation where a large amount of uncertainty exists in the available information (e.g., model outputs). This paper investigates the effect of uncertainty on the ranking of options in water management. Different methods for ranking the management options under uncertainty are reviewed and they account for only partial uncertainty information in model outputs. To consider the full uncertainty information, a new ranking procedure is proposed in this paper, which is capable of providing more information to decision makers and at the same time taking their opinions on uncertainty into consideration. The ranking is achieved by conducting pair-wise comparison of management options, on the basis of the risk defined by the probability of obtaining an unacceptable ranking and the mean difference in model outputs in pair-wise comparison. An application example is presented to illustrate the use of the proposed ranking approach. Furthermore, the sensitivity of management option ranking to different ranking methods and to model uncertainty is also investigated.