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91.
水源涵养是评价陆地生态系统服务功能的重要指标,然而学界对水源涵养功能概念和计算方法仍存在诸多争论。这一方面说明水源涵养功能评估具有重要的现实意义,同时也说明其概念的复杂性和模糊性,亟需从生态学和水文学的基本理论出发,厘清水源涵养功能概念的内涵和评估方法,促进科学决策和有效管理。研究水源涵养功能时,生态学家更关注陆地生态系统的蓄水能力(Smax),而水文学家更关注流域的产流量(Q),两者均具有合理性,但各有侧重,若不分别辨析,极易造成概念混淆。理论和数据分析表明,蓄水能力和产流量虽然联系紧密,但概念完全不同。陆地生态系统的Smax决定了流域对降水的分配:即蒸散发(绿水)和Q(蓝水),Smax和Q在降水量一定的情况下往往存在此消彼长的关系。研究发现生态系统的根区蓄水能力(SRmax)是联系绿水和蓝水的核心要素,是水源涵养功能评估的关键变量。大尺度根区蓄水能力主要由气候决定,可借鉴工程水文中设计水库的累积曲线法,根据生态系统用水的生存策略通过气候反演。最后,本文提出3点建议:(1)在实践中分别评估生态系统的绿水和蓝水涵养功能;(2)进一步全面考虑冰川积雪、地下水等多要素的水源涵养功能;(3)...  相似文献   
92.
不透水面作为反应城市表征变化和区域城镇化的重要技术指标,其位置、图斑大小、空间分布等信息在地表水热循环和能量平衡等领域被广泛需求。传统方法大都基于单一时相信息提取不透水面,而忽略多时相所蕴含的丰富信息。因此,本文提出多时相信息融合的不透水面级联提取方法,利用Landsat-8 OLI遥感影像分析归一化植被指数(Normalized Difference Vegetation Index, NDVI)、改进的归一化水体指数(Modified Normalized Difference Water Index, MNDWI)和归一化建筑指数(Normalized Difference Building Index, NDBI)年内时序变化特点和典型地物间多时相波谱曲线的协同特征,并归纳不透水面多时相变化规律;再根据先验知识所获取的有效地表信息,进行多时相分级提取不透水面信息。此外,基于实地考察数据和同期2 m GF-1遥感影像屏幕数字化生成30 m不透水面图斑,进行精度验证、分析和对比单时相、四季相及多时相3种时序情况下的提取精度。结果表明:单时相提取不透水面总精度最低,四季相提取精度优于单时相,而多时相提取精度最高(精度可达93.66%,Kappa系数为0.81)。本方法在偏远城镇不透水面的有效识别中显露潜在优势,可为不透水面提取方法融合时序波谱特征提供新思路。  相似文献   
93.
For those interested in ethical research, quantitative methods are often dismissed as apolitical; as unreflective exercises in ‘mere counting’. If, however, in doing research, we bring into being the very worlds we purport to describe, the question begs: what kinds of worlds might quantitative methods bring into being? Is there space for a reflexive, quantitative research agenda? In this paper, I will discuss an action-based predominantly quantitative research project that aimed to investigate the diverse impacts of sustainable agriculture on small-scale farmers in the Philippines. The study, one of the largest ever undertaken on organic rice production, was consciously designed, not merely to describe, but to perform organic agriculture differently. While most quantitative, and indeed much qualitative, research ignores its performativity, this research was intended to enact a reality of sustainable agriculture as a viable and vital alternative to mainstream, capitalist agriculture.  相似文献   
94.
Increasing recognition of the value of practice-based or experiential knowledge in natural resource management justifies the creation of a new category of articles in Society & Natural Resources that we are calling Practice-Based Knowledge (PBK). The rationale for focusing on PBK is due to its key role in the emergence of hybrid governance institutions across state, market, and civil society, understanding the complexity of dynamic socioecological systems, recognizing the challenges of multiple knowledge systems and context-specific practices, embracing the power of informal institutions and civic science, and engaging debates on the growing prevalence of market-oriented conservation. The goal is to provide a dedicated space within the published, peer-reviewed literature for scholars, government officials, nonprofit managers, and engaged citizens to share experiences informed by practical action. Relevant and timely practice-based insights may improve understanding and management of social and ecological processes and systems, while also offering the potential to contribute to theory.  相似文献   
95.
Traditional ecological knowledge (TEK) guides resource management across the globe, but is at risk amid social and ecological change. This has prompted numerous calls for TEK maintenance efforts, but these remain largely unexamined in the literature. Here, we discuss three examples of in situ TEK maintenance from Malekula Island in Vanuatu, locally known as kastom schools. Based on qualitative data, we find that the kastom schools may create several opportunities to maintain TEK (e.g., establishing local control over education), and argue that they represent the creative and adaptive management of tradition in dynamic social–ecological contexts. However, a number of challenges, both practical (e.g., lack of funding) and epistemological (e.g., changing modes of cultural transmission), threaten the efficacy of the kastom schools. We argue that in situ modes of TEK maintenance have promise, but that issues of power and heterogeneity require serious consideration if such measures are to succeed.  相似文献   
96.
Earthquake emergency response is one of the three earthquake disaster mitigation work systems in China, already achieving good results in some earthquake disaster mitigation situations. Earthquake emergency plans and emergency command systems are among the most important research and operations components of emergency response. These components commonly come with challenges, such as the pertinence of emergency commands and the operability of the countermeasures to be improved. The promise for solving this problem resides with applying knowledge that aids intelligence creation for decision-making. In this paper, we put forward a conceptual model of knowledge for earthquake disaster emergency response (EDER); compositions of EDER knowledge are introduced within architecture. A modeling method incorporating geo-ontology is used to build basic modeling primitives. Geo-ontology serves to represent geospatial characteristics of the EDER knowledge and addresses a need for semantic interoperability in the modeling process. A decision problem framework and a case study have been used as theoretical framework and an application test, respectively, to evaluate the EDER knowledge architecture and models. The EDER knowledge model provides a foundation for intelligent emergency response that helps solve knowledge problems to improve earthquake disaster response.  相似文献   
97.
Dr. David Mark is widely regarded as a path-breaking researcher in geographic information science. What are the structural and temporal characteristics of his intellectual contributions, as seen through the eyes of the broader academic community? Aiming to answer that question, this article presents a scientometric analysis of publications that have been cited alongside David Mark’s papers. In deliberate contrast to the widespread focus on using citation data to condense scientific impact into a handful of indicators, the methodological contribution of this study lies in its mix of computational and visualization approaches. In the search for latent domain structures, state-of-the-art practices in information science, bibliometrics, and network visualization are combined and extended. An initial network of 50,000+ publications and 4,000,000+ document co-citations undergoes a series of transformations reducing it to 9000 publications that are then clustered in a two-stage process, leading to 678 communities whose co-citation linkages are used to delineate 19 super-communities. To enable replication of this approach for other studies, much focus in this article is on detailed discussion of that workflow as well as on highlighting the reasoning behind the choices made among data sources and analytical methods. The topical evolution of David Mark’s domain of influence is explored in some detail, based on tabular and graphic representations of extracted community structures. Results confirm not only the enormous overall breadth of his influence but also how lasting and recurrent it has been in some areas.  相似文献   
98.
Several tuna regional fisheries management organizations (t-RFMOs) have adopted retention requirements for skipjack, bigeye and yellowfin tunas caught by purse seine vessels to reduce discards, create disincentives to catch small fish, and incentivize the development and adoption of more selective technologies. Although retention policies in the t-RFMOs have been limited to target tunas in purse seine fisheries, some have advocated for an expansion of those policies, and t-RFMOs could consider expanding retention policies to a greater number of species and/or to other gear types. This paper discusses the benefits and costs of broader retention policies for purse seine and longline tuna fisheries in the western and central Pacific Ocean (WCPO). Using bycatch data from observers and logbooks from the U.S. purse seine and longline fleets operating in the WCPO, this paper documents the types and magnitude of fish discarded. For the purse seine fishery, this information was used to estimate direct impacts of having to off-load at the initial point of landing in key Pacific Island ports. For the longline fishery, estimates of direct impacts were limited to Honolulu and Pago Pago, American Samoa, the two primary ports where U.S. catch is landed. Expanding retention policies beyond the target tunas and to other gear types would further reduce discarding and possibly provide stronger incentives to develop and use more selective techniques. Beyond impacts to the ecosystem and fisher behavior, adopting broader retention policies may have other implications, and this paper explores those implications on vessels, processors, and communities. In general, as is the case with most direct interventions on fishing operations, there will be both benefits and costs, and the magnitude of those impacts will depend on the scope and extent of any expanded retention policy.  相似文献   
99.
王祎婷  谢东辉  李小文 《遥感学报》2014,18(6):1139-1146
当前的遥感科学面临着遥感数据获取能力与数据应用能力之间突出的供需矛盾。尺度问题作为遥感科学中的关键问题,既限制了遥感作为一门科学向系统性、普适性的发展,又限制了遥感应用能力的发展。本文对定量遥感中的尺度问题进行了梳理,包括:遥感与传统站点观测之间的不一致、不同尺度遥感产品之间的不一致、机理模型的尺度适用问题,以及遥感产品与用户需求时空尺度间的不一致。对遥感中的尺度转换方法展开了讨论,总结了尺度转换的关键问题在于原数据信息量不足时引入额外信息和保留关键信息两方面。提出了构造地理要素趋势面的基本构想,搭建了一个具有普适性的尺度转换方法框架。核心内容是充分利用地表环境要素时间、空间上的信息作为先验知识,通过关联遥感观测新信息和先验趋势面生成指定时空尺度的地表要素产品。  相似文献   
100.
Citizen support for climate policies is typically seen as an important criterion in climate policy making. Some studies of climate policy support assume that a significant number of citizens need to be aware of the policies in question and able to provide informed opinions. In this study, we probe this assumption using a web-based survey of residents of the Canadian province of British Columbia (n = 475) by assessing: (1) citizen awareness and knowledge of climate policies, (2) citizen support for different climate policies, (3) the relationship between citizen knowledge and policy support, and (4) the effect of information provision on policy support. Our main finding is that most survey respondents are not aware of any of British Columbia's climate policies, and have little understanding of the potential effect of these on reducing greenhouse gas emissions. Once they are made aware of different types of climate policies, respondents are more likely to express support for regulations, such as the zero-emissions electricity standard and energy efficiency regulations, and less likely to support a carbon tax. Statistical analysis indicates that citizen knowledge of policy is not associated with higher policy support. Furthermore, providing information on likely policy effectiveness to our survey respondents did not translate into higher support, suggesting that widespread knowledge and well-informed citizen support are not necessarily required for implementation of effective climate policies.  相似文献   
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