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951.
人工造林被认为是增加碳汇、保持水土和提高水质最有效的方法之一,造林林种的不同将产生不同的生态效应。通过调研土壤、气象及生态化学计量参数等对CENTURY模型进行本地化,模拟冀西北水源涵养区主要针叶造林树种 [落叶松(dahurian larch)、油松(pinus tabulaeformis)、侧柏(oriental arborvitae)和樟子松(Pinus sylvestris var. mongolical)] 的生态效应,并结合文献数据评价模型拟合精度。模型模拟结果显示:与幼龄林相比,落叶松、油松、侧柏和樟子松中龄林的土壤C、N、P总储量分别增加了3.37%、3.98%、2.84%和1.82%,土壤含水量增加了151.25%、73.62%、41.83%和94.98%。不同林种两个林龄平均蒸发量比较显示,落叶松(338.85 mm)<油松(399.86 mm)<侧柏(400.52 mm)<樟子松(401.82 mm)。落叶松可以作为水源涵养区造林的优选树种。樟子松和落叶松具有较强的N、P吸收能力,建议在农业污染的下游区域推广樟子松和落叶松的种植。  相似文献   
952.
金沙江下游(以下简称“金下”)是重要的鱼类种质资源保护区,也是长江大保护关注的重要区域.在当前金下几座大型梯级水电站逐渐投入运行的背景下,区域内的水生态保护问题受到广泛关注.本研究中通过对金下3条主要支流(黑水河、西溪河和赤水河)进行底栖动物群落相似性分析,并结合环境因子对其相似性格局的影响进行了分析,探讨黑水河作为金沙江替代生境的可能性.研究发现,三条河流底栖动物主要由蜉蝣目、毛翅目和双翅目组成,三条河流中绝对优势类群均为蜉蝣目.黑水河和赤水河底栖动物的密度、生物量和生物多样性总体上高于西溪河.底栖动物群落相似性比较发现,黑水河与赤水河的上游群落结构相似性较高,且均以四节蜉科的敏感种为主要优势类群,而与距离黑水河更近的西溪河则表现出较低的相似性.典范对应分析发现海拔和总氮是影响底栖动物群落结构最显著的因子(P < 0.05),分别代表了区域尺度的因子和局域生境的特征.虽然赤水河上游总体上受总氮影响较高,但相较于其他地区,其群落结构依然与黑水河上游更为相似,可能归因于两条河流更相似的物理生境.这表明即便在较大的空间尺度上,局域微生境对底栖动物群落仍具有较强的塑造作用.黑水河因与生态状况良好的赤水河在底栖动物群落相似性、生物量以及多样性特征上均较为相似,可以推测黑水河在该区域内可作为替代生境承担部分生态功能.  相似文献   
953.
Agricultural water management (AWM) is an interdisciplinary concern, cutting across traditional domains such as agronomy, climatology, geology, economics, and sociology. Each of these disciplines has developed numerous process‐based and empirical models for AWM. However, models that simulate all major hydrologic, water quality, and crop growth processes in agricultural systems are still lacking. As computers become more powerful, more researchers are choosing to integrate existing models to account for these major processes rather than building new cross‐disciplinary models. Model integration carries the hope that, as in a real system, the sum of the model will be greater than the parts. However, models based upon simplified and unrealistic assumptions of physical or empirical processes can generate misleading results which are not useful for informing policy. In this article, we use literature and case studies from the High Plains Aquifer and Southeastern United States regions to elucidate the challenges and opportunities associated with integrated modeling for AWM and recommend conditions in which to use integrated models. Additionally, we examine the potential contributions of integrated modeling to AWM — the actual practice of conserving water while maximizing productivity. Editor's note : This paper is part of the featured series on Optimizing Ogallala Aquifer Water Use to Sustain Food Systems. See the February 2019 issue for the introduction and background to the series.  相似文献   
954.
Wetlands should not be considered as independent objects but as dynamically connected objects, collectively known as wetlandscapes. We developed a framework that analyzes the influences of wetland suitability and connectivity on amphibian distributions. We defined two indices: a Wetland Suitability Index describing wetland quality and a Movement Permeability Index characterizing wetland connectivity for amphibian population dynamics. These indices were calculated from raster datasets and time‐varying inundation estimates. The indices were used to define a wetlandscape and an amphibian model was used to simulate population dynamics within the wetlandscape. The framework was applied to the Nose Creek watershed, a highly modified wetlandscape in Alberta, Canada. Two amphibian species were selected with different habitat preferences: the Northern Leopard Frog that prefers wet habitats and has high mobility over land, and the Great Plains Toad that prefers terrestrial habitats and has low mobility over land. We found each amphibian species had a “preferred” wetlandscape, reflecting their life cycle traits and migration strategies which in turn were dependent on the hydrological and ecological connections within the wetlandscape. This study highlights the importance of investigating both individual wetlands and the wetlandscape and considering both wetland habitat quality and connectivity as non‐substitutable properties that act jointly, but differently, on population dynamics.  相似文献   
955.
弃渣场作为铁路建设项目水土流失最为严重的部分,其防护应提到首要位置。针对低山丘陵区铁路建设涉及的凹地型、坡地型、沟道型弃渣场,从弃渣场选址原则、不同类型的弃渣场比较、防护措施设计进行分析和阐述,构建完整的水土流失防治体系,为同类型铁路建设项目弃渣场防护措施设计提供参考。  相似文献   
956.
This study used an experience sampling design to examine the spillover effects of experienced workplace incivility from organizational insiders (coworkers and supervisors, respectively) and organizational outsiders (patients and their visitors) on targets' work‐to‐family conflict and to test the mediating effect of burnout and the moderating effect of display rules. Data collected over five consecutive weeks from 84 full‐time nurses showed that within individuals, weekly experiences of coworker incivility and outsider incivility were positively related to weekly experience of work‐to‐family conflict, and burnout mediated these relationships while controlling for initial level of burnout before participants started a week's work. In addition, display rules, defined as the extent to which individuals perceive they are expected to display desired positive emotions and suppress negative emotions at work, moderated the relationship between outsider incivility and burnout; specifically, the positive relationship between weekly outsider incivility and burnout was stronger for individuals who perceived a higher level of display rules. Our findings contribute to the literature by demonstrating the mediating effect of burnout and the moderating effect of perceived display rules in the relationship between workplace incivility from multiple sources and work‐to‐family conflict from a resource perspective.  相似文献   
957.
Urban water resources have been facing significant pressure from population growth, urbanization, and climate change. A system dynamics urban water management model was proposed to simulate the dynamic interactions between urban water demands and society, economy, climate, and water conservation. The residents'' water conservation willingness was incorporated in the model and water-saving effects were quantified. The simulation results for Macau showed that population size was the main driving force for urban water demand. The change of temperature and precipitation has obvious effects on the landscape water demand. The water demand output is sensitive to the change in population, per capita demand, and temperature. Increased precipitation will reduce urban water demand and increased economic growth will increase water demand. By implementing integrated water conservation measures and improved water conservation willingness, water demand could be reduced by 17.5%.  相似文献   
958.
随着全球经济的飞速发展,经济受资源和环境约束的矛盾接近临界。而人们对环境质量的需求不断上升,在此大背景下,节能环保产业应运而生。在介绍国际节能环保产业和分析中国节能环保产业现状的基础上,分析融资渠道不够畅通,市场活力有待激发,资本市场亟待完善,产业创业还需推进等一系列制约中国节能环保产业发展的问题,并从理清管理体制,畅通融资渠道,健全资本市场,推进产业创业等方面给出了建议。  相似文献   
959.
Scholars observe an increased involvement of citizens in green space governance. This paper focuses on green self-governance, in which citizens play a major role in realizing, protecting and/or managing green space. While existing research on green self-governance focuses mostly on specific cases, we aim to contribute towards a large overview via an inventory of 264 green self-governance practices across The Netherlands. With this, we discuss the relevance of green self-governance for nature conservation and its relationship with authorities. In our analysis, we show that green self-governance practices are very diverse: they pursue a wide variety of physical and social objectives; employ a multitude of physical and political activities; involve different actors besides citizens; mobilize different internal and external funding sources; and are active within and outside of protected areas. While green self-governance can contribute towards protection and management of green space and towards social values, we highlight that this contribution is mostly of a local relevance. Most practices are small scale and objectives do not always match those of authorities. Although we speak of self-governance, authorities play an important role in many practices, for example, as financial donor, landowner or regulatory authority. In this, self-governance is often not completely ‘self’.

Abbreviations: PAA: Policy Arrangement Approach; NNN: National Nature Network; N2000: Natura 2000; NCOs: Nature Conservation Organizations; NGOs: Non-governmental organizations  相似文献   

960.
Protected areas cannot be considered as elements isolated from the human groups that inhabit them. Consideration of the social factor is fundamental to guarantee the success of any management model. In this sense, analyzing the perception of people who live in protected areas can be a key tool for the formulation of proposals for improving the existing models. This article explores perceptions of local residents in the Sierra Nevada Protected Area in Southern Spain and identifies the socio-demographic factors that affect these perceptions. The main objective is to generate relevant data for the protected area management team. The recommendations we can offer entail a review of the communication plan and participatory strategy considering social differences in perceptions of the local population.  相似文献   
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