首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 140 毫秒
1.
Bisby FA 《Science (New York, N.Y.)》2000,289(5488):2309-2312
The massive development of biodiversity-related information systems on the Internet has created much that appears exciting but chaotic, a diversity to match biodiversity itself. This richness and the arrays of new sources are counterbalanced by the maddening difficulty in knowing what is where, or of comparing like with like. But quietly, behind the first waves of exuberance, biologists and computer scientists have started to pull together in a rising tide of coherence and organization. The fledgling field of biodiversity informatics looks set to deliver major advances that could turn the Internet into a giant global biodiversity information system.  相似文献   

2.
森林资源变化遥感监测技术研究进展   总被引:11,自引:0,他引:11  
森林资源的变化对于全球碳循环、气候变化、生物多样性和生态环境有重要影响.及时、准确地获取森林资源变化信息,对于森林经营科学决策与可持续发展具有重要意义.本文对森林资源变化遥感监测技术进行了系统总结与分析,指出了各类方法的优缺点和应用范围,对影响森林资源变化遥感监测结果的因素进行了讨论,并给出了结论和建议.  相似文献   

3.
Global biodiversity scenarios for the year 2100   总被引:18,自引:0,他引:18  
Scenarios of changes in biodiversity for the year 2100 can now be developed based on scenarios of changes in atmospheric carbon dioxide, climate, vegetation, and land use and the known sensitivity of biodiversity to these changes. This study identified a ranking of the importance of drivers of change, a ranking of the biomes with respect to expected changes, and the major sources of uncertainties. For terrestrial ecosystems, land-use change probably will have the largest effect, followed by climate change, nitrogen deposition, biotic exchange, and elevated carbon dioxide concentration. For freshwater ecosystems, biotic exchange is much more important. Mediterranean climate and grassland ecosystems likely will experience the greatest proportional change in biodiversity because of the substantial influence of all drivers of biodiversity change. Northern temperate ecosystems are estimated to experience the least biodiversity change because major land-use change has already occurred. Plausible changes in biodiversity in other biomes depend on interactions among the causes of biodiversity change. These interactions represent one of the largest uncertainties in projections of future biodiversity change.  相似文献   

4.
Purves D  Pacala S 《Science (New York, N.Y.)》2008,320(5882):1452-1453
Dynamic global vegetation models (DGVMs) have shown that forest dynamics could dramatically alter the response of the global climate system to increased atmospheric carbon dioxide over the next century. But there is little agreement between different DGVMs, making forest dynamics one of the greatest sources of uncertainty in predicting future climate. DGVM predictions could be strengthened by integrating the ecological realities of biodiversity and height-structured competition for light, facilitated by recent advances in the mathematics of forest modeling, ecological understanding of diverse forest communities, and the availability of forest inventory data.  相似文献   

5.
湿地生态系统是地球上最丰富的生态系统之一,具有丰富的生物多样性,为工业、农业、能源、医疗业等提供大量生产原料,同时又能贮藏水源、调节洪水、补给地下水、净化水质,对人类具有巨大的环境和社会价值。近年来,人类活动造成的气候变化越来越明显,湿地生态环境又非常脆弱,极易受气候变化影响,尤其是温度升高和降水量减少,都会对湿地的生态环境产生重大影响,从而导致生物多样性减少、湿地退化甚至消失。本文从多方面论述了气候变化对湿地生态环境及生物多样性的影响,为湿地保护和利用提供参考。  相似文献   

6.
Slowly changing boundary conditions can sometimes cause discontinuous responses in climate models and result in relatively rapid transitions between different climate states. Such terrestrially induced abrupt climate transitions could have contributed to biotic crises in earth history. Ancillary events associated with transitions could disperse unstable climate behavior over a longer but still geologically brief interval and account for the stepwise nature of some extinction events. There is a growing body of theoretical and empirical support for the concept of abrupt climate change, and a comparison of paleoclimate data with the Phanerozoic extinction record indicates that climate and biotic transitions often coincide. However, more stratigraphic information is needed to precisely assess phase relations between the two types of transitions. The climate-life comparison also suggests that, if climate change is significantly contributing to biotic turnover, ecosystems may be more sensitive to forcing during the early stages of evolution from an ice-free to a glaciated state. Our analysis suggests that a terrestrially induced climate instability is a viable mechanism for causing rapid environmental change and biotic turnover in earth history, but the relation is not so strong that other sources of variance can be excluded.  相似文献   

7.
The location of and threats to biodiversity are distributed unevenly, so prioritization is essential to minimize biodiversity loss. To address this need, biodiversity conservation organizations have proposed nine templates of global priorities over the past decade. Here, we review the concepts, methods, results, impacts, and challenges of these prioritizations of conservation practice within the theoretical irreplaceability/vulnerability framework of systematic conservation planning. Most of the templates prioritize highly irreplaceable regions; some are reactive (prioritizing high vulnerability), and others are proactive (prioritizing low vulnerability). We hope this synthesis improves understanding of these prioritization approaches and that it results in more efficient allocation of geographically flexible conservation funding.  相似文献   

8.
The loss of biodiversity can have significant impacts on ecosystem functioning, but the mechanisms involved lack empirical confirmation. Using soil microcosms, we show experimentally that functional dissimilarity among detritivorous species, not species number, drives community compositional effects on leaf litter mass loss and soil respiration, two key soil ecosystem processes. These experiments confirm theoretical predictions that biodiversity effects on ecosystem functioning can be predicted by the degree of functional differences among species.  相似文献   

9.
于娇  纪凤伟 《安徽农业科学》2012,40(28):13879-13880
对景观稳定性途径、绿色廊道途径和焦点物种途径3种景观生态规划途径进行阐述和分析,从不同的角度提出了生物多样性保护的规划方法。认为在进行生物多样性保护规划时,应当将3种途径结合起来考虑,扬长避短,取长补短,从而创造出一种更加完善的生物多样性保护方法,以期对我国的景观生态规划起到借鉴和促进作用。  相似文献   

10.
城市生物多样性分布格局由自然生态环境和城市化过程所决定;其动态和机理与自然生态系统迥然不同.城市生物多样性为城市生态系统提供了诸多生态系统功能和服务,对改善城市环境、维持城市可持续发展有着重要的意义和作用.城市化过程深刻改变了城市的生物多样性分布格局,导致了诸如本地物种多样性降低、外来物种多样性增加、物种同质化等一系列问题.近年来,城市生物多样性受到学界高度关注,大量研究结果既回答了一些关键性问题,又提出了诸多新的论题和挑战.分析了当前城市生物多样性分布格局研究的若干热点问题,总结了影响城市生物多样性格局的主要因素,探讨了城市生物多样性格局研究方法的关键问题,指出了未来城市生物多样性研究的发展方向,特别强调了城市生物多样性的生态系统功能研究在未来城市生物多样性研究中的重要地位.  相似文献   

11.
Anthropogenic global changes threaten species and the ecosystem services upon which society depends. Effective solutions to this multifaceted crisis need scientific responses spanning disciplines and spatial scales. Macroecology develops broad-scale predictions of species' distributions and abundances, complementing the frequently local focus of global change biology. Macroecological discoveries rely particularly on correlative methods but have still proven effective in predicting global change impacts on species. However, global changes create pseudo-experimental opportunities to build stronger, mechanistic theories in macroecology that successfully predict multiple phenomena across spatial scales. Such macroecological perspectives will help address the biotic consequences of global change.  相似文献   

12.
Climate change is confronting African farmers with growing uncertainties. Advances in seasonal climate predictions offer potential for assisting farmers in dealing with climate risk. Experimental cases of forecast dissemination to African rural communities suggest that participatory approaches can facilitate understanding and use of uncertain climate information. But few of these studies integrate critical reflections on participation that have emerged in the last decade which reveal how participatory approaches can miss social dynamics of power at the community level and in the broader context. Furthermore, neither climate application research nor theoretical critiques of participation fully examine the culturally constructed nature of participation. Drawing on sociolinguistic analysis, in-depth interviews, and ethnographic observation, this paper examines how Ugandan farmers engage in participation in the context of discussions of seasonal climate forecasts. Forecasts were presented to farmers groups whose members were then asked to discuss the forecast among themselves. In doing so, groups sought to develop a common understanding of the forecast and consensual plans for response strategies. Focusing on one particular group meeting as an example, we show how different cultural styles of participation affect the interpretation of the forecast and the formulation of response strategies. Group interaction is shown to be mostly structured around two styles of participation. On the one hand, there is the “Western” style advocated by NGOs and the government, which centers on ensuring that all individuals who are present have opportunities to speak during discussion and to vote on group decisions. On the other hand, a “Kiganda” style of participation emphasizes the importance of affirming ties to a collectivity, respect for social hierarchy, deployment of good manners, and consensus building. The case study illuminates how the performance of different styles of participation is grounded in localized frameworks of language and culture but also draw on political and policy discourses at the national level. Although a cultural high value on consensus may work in favor of prominent members, the availability of multiple styles of participation also enables group members to exercise their agency in positive ways. Attention to the interplay of different styles of participation throws light on the subtle social processes that shape how knowledge is assessed, which sources are trusted, which and whose interpretations prevail, what options are deemed viable, how costs and benefits are calculated, and whose resources are mobilized in the effort to reduce vulnerability to climate risk. These are key questions for an assessment of the role of boundary organizations, such as farmer associations, in the communication and application of climate forecasts in agriculture.  相似文献   

13.
The extensively built long-distance water transmission pipelines have become the main water sources for urban areas. To ensure the reliability and safety of the water supply, from the viewpoint of overall management, it would be necessary to establish a system of information management for the pipeline. The monitoring, calculating and analyzing functions of the system serve to give controlling instructions and safe operating rules to the automatic equipment and technician, making sure the resistance coefficient distribution along the pipeline is reasonable; the hydraulic state transition is smooth when operating conditions change or water supply accidents occur, avoiding the damage of water hammer. This paper covered the composition structures of the information management system of long-distance water transmission pipelines and the functions of the subsystems, and finally elaborated on the approaches and steps of building a mathematics model for the analysis of dynamic hydraulic status.  相似文献   

14.
The Phanerozoic fossil record of marine animal diversity covaries with the amount of marine sedimentary rock. The extent to which this covariation reflects a geologically controlled sampling bias remains unknown. We show that Phanerozoic records of seawater chemistry and continental flooding contain information on the diversity of marine animals that is independent of sedimentary rock quantity and sampling. Interrelationships among variables suggest long-term interactions among continental flooding, sulfur and carbon cycling, and macroevolution. Thus, mutual responses to interacting Earth systems, not sampling biases, explain much of the observed covariation between Phanerozoic patterns of sedimentation and fossil biodiversity. Linkages between biodiversity and environmental records likely reflect complex biotic responses to changing ocean redox conditions and long-term sea-level fluctuations driven by plate tectonics.  相似文献   

15.
北方森林生态系统对全球气候变化的响应研究进展   总被引:2,自引:1,他引:1  
北方森林是地球上第2大生物群区,约占陆地森林面积的30%,提供了从局地到全球的生态系统服务功能。1850年以来,全球性持续升温不断显现,2000—2050年全球至少升高2 ℃,甚至更高。预计到2100年,北方森林区冬季平均温度将升高1.3~6.3 ℃。与此同时,几乎所有的北方森林生态系统功能都将会受到影响,尤其是近几十年来,该区域发生了很多与温度升高相关的潜在生态响应。本文从碳循环、生物多样性、干旱化和林火发生频率以及冻土变化等方面具体综述了北方森林生态系统对于全球气候变化的响应。响应结果如下:1)气候变化对于北方森林碳循环动态的影响是极其复杂的,迄今为止并没有达成共识, 分解对于温度的反应敏感程度至今仍存在很多不确定性。2)动物、植物和微生物(真菌)均对气候变化产生了一定的响应,表现为动物和植物的分布区进一步北移,但真菌的多样性和生产力响应机制尚无法确定。3)北方森林区随气候变化表现为进一步的干旱化和林火发生明显增加。4)北方森林区与冻土伴生,冻土随气候变暖表现出了面积缩小和活动层扩大的趋势。可见,北方森林对气候变化响应明显,尽管到目前为止有些响应机制尚不清楚,但变化趋势十分明显。本文旨在为北方森林的经营和管理提供基础数据和技术支持,实现北方森林的可持续经营。   相似文献   

16.
Border-check irrigation is the predominant method of applying water to dairy pastures in Australia. Dairy pastures consume 40% of total irrigation water in Australia and, with irrigation water security in Australia under threat from climate variability/change and rising demands from other users, socio-economic pressure for water savings in the dairying sector are increasing. Currently, there are no simulation tools that successfully link factors controlling irrigation efficiency at the within-bay scale to management factors that drive economic water productivity (principally pasture growth, pasture consumption and animal production).A simulation framework was developed to connect a biophysical research model of weather-soil-plant animal interaction in dairy systems (‘DairyMod’) to a surface irrigation hydraulic model, SRFR (Simulation of basin, border and furrow irrigations). The connection enabled simulation of the effects of border-check irrigation scheduling and event management on irrigated pasture production systems. Modifications were made to DairyMod, in which the paddock surface was represented as a point, so that it could accommodate infiltration data in a one-dimensional form, from the surface irrigation model SRFR. Multiple simulations of DairyMod were run each representing different discrete spatial zones within an irrigation bay, and the SRFR routines connect each discrete spatial zone with information on the advance front water depth.Model integration and the workings of the integrated model are described, and the process used to verify the integrity of the data transferred between the two models is presented. Comparisons of data input and output parameters from the stand-alone models and the integrated model confirmed that the data transfer between the models within the integrated framework did not introduce new sources of errors.Preliminary output for a scenario involving three irrigation durations is also presented. The scenario represented a perennial ryegrass based pasture on a texture contrast clay loam soil over a period of 10 years using measured climate data. Model predictions agreed well with data reported in the literature for annual irrigation amounts and pasture growth. It was demonstrated that the integrated model could be used effectively to determine how pasture production varied with changes in irrigation management such as irrigation duration. A limitation of the integrated model was its dependence on two sets of infiltration models that were difficult to relate to each other.  相似文献   

17.
Global desertification: building a science for dryland development   总被引:6,自引:0,他引:6  
In this millennium, global drylands face a myriad of problems that present tough research, management, and policy challenges. Recent advances in dryland development, however, together with the integrative approaches of global change and sustainability science, suggest that concerns about land degradation, poverty, safeguarding biodiversity, and protecting the culture of 2.5 billion people can be confronted with renewed optimism. We review recent lessons about the functioning of dryland ecosystems and the livelihood systems of their human residents and introduce a new synthetic framework, the Drylands Development Paradigm (DDP). The DDP, supported by a growing and well-documented set of tools for policy and management action, helps navigate the inherent complexity of desertification and dryland development, identifying and synthesizing those factors important to research, management, and policy communities.  相似文献   

18.
Two mail surveys were carried out in Denmark and the Eastern Corn Belt, USA in 2002. Questionnaires were sent to 580 farmers who had used precision agriculture (PA) and 198 responses were received. The surveys focused on the current status of use of PA in both countries, including: PA practices, equipment and software, Internet and e-mail use, information sources for PA, satisfaction level from service providers, data handling, interpretation, storage and ownership, value of data for decision making, changes in management practices, desired information and services, and the next planned step in the practice of PA. The survey results showed more similarities in practicing PA between the two countries than differences. Time requirement and high cost of data handling were cited as the main problems. Survey respondents found soil maps to be more valuable than yield maps in management decisions. About 80% of the respondents would like to store the PA data themselves. The majority of the respondents indicated that they have changed their management practices due to PA, but not substantially. Some 90 of the respondents used the Internet and e-mail for agricultural purposes, but only a small number for PA websites.  相似文献   

19.
碱蓬属(Suaeda)植物是一类典型的真盐生植物,属于重要的盐生植物资源,全球广泛分布.人们已经对20种碱蓬属植物进行了观察和盐胁迫实验,研究了不同器官或组织的生理生化特征及其对盐胁迫的反应,并基于这些研究分析了盐胁迫的应答机制.叶片肉质化、细胞内离子区域化、渗透调节物质增加和抗氧化系统能力增强是碱蓬属植物响应和适应盐胁迫的重要方式和途径.但迄今为止的研究工作尚有一定的局限性,主要包括:研究工作主要集中在植物地上部分,而对植物地下部分的研究较少;多是少数生物学指标或生理学现象的单独观察,而缺乏对生理代谢过程的整体和综合分析;针对某种碱蓬的独立分析较多,而与近缘种的比较研究较少;植物对中性盐胁迫的反应研究较多,而对碱性盐的研究较少.为进一步系统阐明碱蓬属植物的耐盐机制,今后的工作应注重碱蓬属植物响应和适应盐胁迫的信号网络和调控机制研究,基于系统生物学研究思路,采用现代组学技术探索该属植物响应盐胁迫的由复杂信号网络调控的特殊生理特征和特异代谢途径.  相似文献   

20.
Accelerated human population growth at protected area edges   总被引:1,自引:0,他引:1  
Protected areas (PAs) have long been criticized as creations of and for an elite few, where associated costs, but few benefits, are borne by marginalized rural communities. Contrary to predictions of this argument, we found that average human population growth rates on the borders of 306 PAs in 45 countries in Africa and Latin America were nearly double average rural growth, suggesting that PAs attract, rather than repel, human settlement. Higher population growth on PA edges is evident across ecoregions, countries, and continents and is correlated positively with international donor investment in national conservation programs and an index of park-related funding. These findings provide insight on the value of PAs for local people, but also highlight a looming threat to PA effectiveness and biodiversity conservation.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号