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881.
Farm ponds have high conservation value because they contribute significantly to regional biodiversity and ecosystem services. In Japan pond draining is a traditional management method that is widely believed to improve water quality and eradicate invasive fish. In addition, fishing by means of pond draining has significant cultural value for local people, serving as a social event. However, there is a widespread belief that pond draining reduces freshwater biodiversity through the extirpation of aquatic animals, but scientific evaluation of the effectiveness of pond draining is lacking. We conducted a large‐scale field study to evaluate the effects of pond draining on invasive animal control, water quality, and aquatic biodiversity relative to different pond‐management practices, pond physicochemistry, and surrounding land use. The results of boosted regression‐tree models and analyses of similarity showed that pond draining had little effect on invasive fish control, water quality, or aquatic biodiversity. Draining even facilitated the colonization of farm ponds by invasive red swamp crayfish (Procambarus clarkii), which in turn may have detrimental effects on the biodiversity and water quality of farm ponds. Our results highlight the need for reconsidering current pond management and developing management plans with respect to multifunctionality of such ponds. Efectos del Drenado de Estanques sobre la Biodiversidad y la Calidad del Agua en Estanques de Cultivo  相似文献   
882.
Coral reef fisheries are crucial to the livelihoods of tens of millions of people; yet, widespread habitat degradation and unsustainable fishing are causing severe depletion of stocks of reef fish. Understanding how social and economic factors, such as human population density, access to external markets, and modernization interact with fishing and habitat degradation to affect fish stocks is vital to sustainable management of coral reef fisheries. We used fish survey data, national social and economic data, and path analyses to assess whether these factors explain variation in biomass of coral reef fishes among 25 sites in Solomon Islands. We categorized fishes into 3 groups on the basis of life‐history characteristics associated with vulnerability to extinction by fishing (high, medium, and low vulnerability). The biomass of fish with low vulnerability was positively related to habitat condition. The biomass of fishes with high vulnerability was negatively related to fishing conducted with efficient gear. Use of efficient gear, in turn, was strongly and positively related to both population density and market proximity. This result suggests local population pressure and external markets have additive negative effects on vulnerable reef fish. Biomass of the fish of medium vulnerability was not explained by fishing intensity or habitat condition, which suggests these species may be relatively resilient to both habitat degradation and fishing. Efectos de la Densidad de Poblaciones Humanas y la Proximidad del Mercado sobre Peces de Arrecifes de Coral Vulnerables a la Extinción  相似文献   
883.
Many of the challenges conservation professionals face can be framed as scale mismatches. The problem of scale mismatch occurs when the planning for and implementation of conservation actions is at a scale that does not reflect the scale of the conservation problem. The challenges in conservation planning related to scale mismatch include ecosystem or ecological process transcendence of governance boundaries; limited availability of fine‐resolution data; lack of operational capacity for implementation; lack of understanding of social‐ecological system components; threats to ecological diversity that operate at diverse spatial and temporal scales; mismatch between funding and the long‐term nature of ecological processes; rate of action implementation that does not reflect the rate of change of the ecological system; lack of appropriate indicators for monitoring activities; and occurrence of ecological change at scales smaller or larger than the scale of implementation or monitoring. Not recognizing and accounting for these challenges when planning for conservation can result in actions that do not address the multiscale nature of conservation problems and that do not achieve conservation objectives. Social networks link organizations and individuals across space and time and determine the scale of conservation actions; thus, an understanding of the social networks associated with conservation planning will help determine the potential for implementing conservation actions at the required scales. Social‐network analyses can be used to explore whether these networks constrain or enable key social processes and how multiple scales of action are linked. Results of network analyses can be used to mitigate scale mismatches in assessing, planning, implementing, and monitoring conservation projects. Discordancia de Escalas, Planificación de la Conservación y el Valor del Análisis de Redes Sociales  相似文献   
884.
SUMMARY

This paper describes the evolution of an evaluation method developed initially to assess progress towards sustainable development for various land use activities in Costa Rica. Since that time, the method has been expanded to apply to all types of business activities in any location, and refined so that a numerical score can be provided for each attribute. These scores can then be presented graphically in four categories. The method has since been tested on a variety of businesses and is being refined for electronic submission and display of the results. The benefits of this approach, as well as its shortcomings and some of the problems resolved, are presented.  相似文献   
885.
As one of the dominant large-scale mechanisms proposed to combat climate change, biodiversity loss, and rural poverty, REDD+ (Reducing Emissions from Deforestation and Forest Degradation) has added further complexity to the challenging governance of rights and resources in global forests. As REDD+ is commodifying carbon, concerns emerge about how carbon ownership and its rights can be accommodated into the existing framework that governs local forest resource rights. The Nepalese government has formally entered into REDD+ policy preparations, but it lacks clear legal provisions regarding key forest tenure rights such as carbon ownership, benefit sharing, and the political participation of community forest user groups from national to local. As a result, Nepal’s policy process points toward performance-based carbon forestry in a way that may undermine and weaken existing community tenure rights and forest tenure security.

This paper discusses Nepal’s potential impacts of new REDD+ and carbon ownership arrangements on forest tenure security and community-based forest governance. In a threefold methodological approach, the paper presents three scenarios for a REDD+-oriented tenure reform within the existing framework and assesses their concerns through in-depth qualitative interviews with key stakeholders, representatives, and advocates of Nepal’s community forestry system, complemented by a review of government documents and academic literature of REDD+ lessons so far. The analysis identifies critical concerns for forest tenure security, state-community power relationships, and effective local institutions of the commons, and suggests that Nepal’s REDD+ process is taking place at a particularly consequential time for structural changes of the forest governance framework.  相似文献   
886.
ABSTRACT

Although sustainable development was defined in the Brundtland Report almost 30 years ago, the current usage of the concepts of sustainability and sustainable development remain highly equivocal. In the context of rural communities, multiple interpretations and weak definitions lead to confusion in understanding what comprises a sustainable rural community. Building on existing definitions (e.g. Baker’s, 2006, ‘Ladder of Sustainable Development’), models (principally, The Egan Review’s, 2004, ‘Components of Sustainable Communities’) and findings of this study, a sustainable community is defined and a holistic model of a sustainable place-based rural community is presented. This model, the sustainable community design (SCD) is used as the basis for analysing community sustainability, which is measured using mixed methods and scorecard assessment. Sensitivity of the method is demonstrated with inter- and intra-community variations in sustainability across three diverse Scottish rural communities. Intra-community variations illustrate heterogeneity in community sustainability, explain ambiguity in characterisations of an individual community’s sustainability, and highlight the importance of an interdisciplinary and holistic approach to community development. The SCD framework is presented as a useful tool for meso-level sustainability assessment and to facilitate the sustainable development of rural communities.  相似文献   
887.
运用生态系统定位监测方法,于2011年在上海市奉贤区海湾国家森林公园内设置面积为100 m×100 m的样地,记录样地内的所有植物种类,定位调查高于1.3m的木本植物,分析其种类组成、区系成分、垂直结构和水平结构.结果表明,1 hm2样地内共记录有维管束植物31科68属73种,其中温带区系成分占总属数的51.8%,热带区系成分占46.4%.高于1.3m的木本植株3 094株,其中常绿树种6种,共1 670株,重要值占48.0%;落叶树种7种,共1 424株,重要值占52.0%.女贞(Ligustrum lucidum)、喜树(Camptotheca acuminata)、椤木石楠(Photinia davidsoniae)、乌桕(Sapium sebiferum)、黄山栾树(Koelreuteria integrifoliola)和香樟(Cinnamomum camphora)的重要值位居前6位,在垂直空间上呈分层结构.在0~50 m尺度范围内,女贞种群均呈集群分布,喜树种群呈均匀-随机-集群分布,椤木石楠和乌桕种群表现为集群-随机-均匀分布,黄山栾树和香樟种群表现为随机-集群-随机分布.从群落结构特征看,样地为以北温带成分、泛热带成分为主的常绿落叶阔叶混交林,表征了该地区自然植被的结构特征.建立长期固定样地可为长三角城市化地区平原地貌上城市森林的发生、发展和演替规律提供长期的数据基础.  相似文献   
888.
油松(Pinus tabulaeformis)耐低温、干旱和贫瘠,是我国北方温性针叶林中分布最广的森林群落,也是我国北方广大地区最主要的本土造林树种之一,火炬(Rhus typhina Linn.)根萌蘖力强,耐寒、耐旱、耐盐碱,是一种适应周围环境能力极强的外来引入种树种。采用空间代替时间的方法,以冀东铁矿不同年份种植的人工火炬林和人工油松林群落为研究对象,采用样方法进行调查取样,分析了2种恢复模式不同演替阶段群落结构的变化,群落动态,同时采用Pielou均匀度指数、Margalef丰富度指数、Shannon-Wiener多样性指数分析了物种多样性在群落演替过程中的动态变化,在此基础上,对比分析了2种恢复模式在生态效益方面的优劣。主要结果如下:1)短期来看,火炬可以迅速提高植被盖度,增加生物量,但是,长期来看,随着火炬的快速萌集繁殖和林分的郁闭,林下草本急剧减少,形成火炬单优群落,而不能形成稳定的顶级群落。2)短期来看,油松生长缓慢,其生态效益远小于火炬群落,但是油松群落经过11年的演替形成了乔-灌-草3层结构,群落结构逐渐完善。3)演替初期火炬群落优势种以猪毛蒿(Artemisia scoparia)、狗尾草(Setaria viridis)等耐干旱的植物为主,演替后期林下物种迅速减少以至大量消失;油松群落经过11年的恢复,群落草本层植物种数逐渐增大,从一年生先锋植物占优势过渡到以白羊草(Bothriochloa ischaemun)和硬质早熟禾(Poa sphondylodes)为建群种,并出现了黄刺玫(Rosa xanthina)和胡枝子(Lespedeza bicolor)等多年生灌木。4)演替初期Margalef丰富度指数、Pielou均匀度指数和Shannon-Wiener指数表现为:火炬群落﹥油松群落,演替后期则相反,这主要是由群落内种间竞争关系和水热环境的差异造成。4)综合植物群落盖度、物种多样性和群落未来的演替趋势,火炬长期的生态效益远不及油松树种。  相似文献   
889.
张堃 《中国环境科学》2018,38(8):2981-2989
以德国分散式污水处理系统为研究对象,通过16S rRNA测序,研究2个反应器中微生物群落结构,利用PICRUSt软件对其功能进行推演.结果表明,冬季,污水厌氧膜生物反应器(AnMBR)内温度20℃,进水COD 712mg/L时,出水可获得52%的COD平均去除率,产气率为122L/kgCOD;固体废物厌氧反应器(PSD)内温度37℃,反应器内COD 3007mg/L时,可获得374L/kgVSS的产气率.2个反应器具有相似的微生物组成,对细菌,Synerigistaceae科的相对丰度最高(AnMBR:24.0%±10.0%;PSD:11.0%±3.1%);对古菌,Methanobacteriaceae科的相对丰度最高(AnMBR:0.6%±0.3%;PSD:13.8%±1.8%);2个反应器的功能基因组成也相似,产甲烷都以H2还原CO2的通路为主.PSD反应器中H2还原CO2通路相关基因、F420合成相关基因、辅酶M合成相关基因的相对丰度都高于AnMBR反应器.  相似文献   
890.
Lacustrine sediment played important roles in migration and transformation of its water soluble organic matter(WSOM), and the source and composition of WSOM would affect water trophic status and the fate of pollutants. However, we know little about the pathway of WSOM transformation and its driving bacterial communities in lacustrine sediment. In the present study, we investigated the spatial distribution patterns of sediment WSOM and its fluorescent fractions across Lake Chaohu using fluorescen...  相似文献   
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