共查询到20条相似文献，搜索用时 15 毫秒
1.
Huston M 《Science (New York, N.Y.)》1993,262(5140):1676-1680
Terrestrial biological diversity is supported by solar energy captured by plants growing in soil. This soil-based plant productivity also provides the foundation for human societies through production of food and renewable forms of energy. Variations in plant productivity, resulting from differences in inherent soil fertility, variations in climate and weather, and differences in chemical inputs and agricultural practices, produce patterns of biological diversity that are associated with the agricultural component of economic productivity. Ecological processes lead to a generally negative relation between the diversity of plant species and potential agricultural productivity at both local and global scales. One implication of this negative relation is that preservation of areas of high plant biodiversity does not require the sacrifice of productive agricultural lands. 相似文献
2.
Ricklefs RE 《Science (New York, N.Y.)》1987,235(4785):167-171
The species richness (diversity) of local plant and animal assemblages-biological communities-balances regional processes of species formation and geographic dispersal, which add species to communities, against processes of predation, competitive exclusion, adaptation, and stochastic variation, which may promote local extinction. During the past three decades, ecologists have sought to explain differences in local diversity by the influence of the physical environment on local interactions among species, interactions that are generally believed to limit the number of coexisting species. But diversity of the biological community often fails to converge under similar physical conditions, and local diversity bears a demonstrable dependence upon regional diversity. These observations suggest that regional and historical processes, as well as unique events and circumstances, profoundly influence local community structure. Ecologists must broaden their concepts of community processes and incorporate data from systematics, biogeography, and paleontology into analyses of ecological patterns and tests of community theory. 相似文献
3.
Bell G 《Science (New York, N.Y.)》2001,293(5539):2413-2418
The central themes of community ecology-distribution, abundance, and diversity-display strongly marked and very general patterns. These include the log-normal distribution of abundance, the relation between range and abundance, the species-area law, and the turnover of species composition. Each pattern is the subject of a large literature that interprets it in terms of ecological processes, typically involving the sorting of differently specialized species onto heterogeneous landscapes. All of these patterns can be shown to arise, however, from neutral community models in which all individuals have identical properties, as the consequence of local dispersal alone. This implies, at the least, that functional interpretations of these patterns must be reevaluated. More fundamentally, neutral community models provide a general theory for biodiversity and conservation biology capable of predicting the fundamental processes and patterns of community ecology. 相似文献
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福建省2000—2013年气象因子的变化趋势 总被引：1，自引：1，他引：0
基于福建省10个气象站2000—2013年的气象观测资料,应用Sen's斜率估计法和Daniel趋势检验法分析了4个气象因子的年际和季节变化趋势及其空间分布,采用Pettitt突变检验法检测突变点的发生.结果表明:在年际和季节变化的趋势中,东南沿海地区的风速显著减弱,西北部地区显著增强;南部地区夏天和秋天的相对湿度显著降低;降水的年际和季节变化不显著;全省气温升高突变集中在2011年;此外,虽然冬天和春天的气温越来越低,夏天气温越来越高,但趋势缓慢不显著,表明福建省气温整体趋于稳定. 相似文献
5.
Stratospheric harbingers of anomalous weather regimes 总被引：13，自引：0，他引：13
Observations show that large variations in the strength of the stratospheric circulation, appearing first above approximately 50 kilometers, descend to the lowermost stratosphere and are followed by anomalous tropospheric weather regimes. During the 60 days after the onset of these events, average surface pressure maps resemble closely the Arctic Oscillation pattern. These stratospheric events also precede shifts in the probability distributions of extreme values of the Arctic and North Atlantic Oscillations, the location of storm tracks, and the local likelihood of mid-latitude storms. Our observations suggest that these stratospheric harbingers may be used as a predictor of tropospheric weather regimes. 相似文献
6.
Analyses of statistical distributions of body mass, population density, and size and shape of geographic range offer insights into the empirical patterns and causal mechanisms that characterize the allocation of food and space among the diverse species in continental biotas. These analyses also provide evidence of the processes that couple ecological phenomena that occur on disparate spatial and temporal scales-from the activities of individual organisms within local populations to the dynamics of continent-wide speciation, colonization, and extinction events. 相似文献
7.
Self-assembly at all scales 总被引：1，自引：0，他引：1
Self-assembly is the autonomous organization of components into patterns or structures without human intervention. Self-assembling processes are common throughout nature and technology. They involve components from the molecular (crystals) to the planetary (weather systems) scale and many different kinds of interactions. The concept of self-assembly is used increasingly in many disciplines, with a different flavor and emphasis in each. 相似文献
8.
金沙江流域高原山地系统分异规律的分析研究 总被引：8，自引：1，他引：8
该文根据长江上游金沙江流域高原山地具有山高坡陡,土壤侵蚀面广、侵蚀量大,支流和干流落差大,搬运能力强;气候条件恶劣、生态环境严重恶化,植被恢复难度大;经济发展普遍滞后,贫困面大等突出特点.利用金沙江流域高原山地系统具有地域分异的规律性这一基本原理,在充分调查分析了该流域内云南47个县、市、区自然生态、社会经济条件的基础上,按照高原山地空间层次结构的多样性,对构成金沙江流域这一极为复杂的开放性景观生态系统的地貌、气候、森林植被、社会经济、土壤侵蚀等多级子系统的分异规律进行分析研究,以求得实现系统恢复与功能需求的一致性,为该流域的生态环境恢复重建提供科学的依据. 相似文献
9.
江西传统生态农业发展历史源远流长,自宋代以来,出现了许多符合生态学原理的"原始"生态农业模式与技术,明清时期得到进一步发展。江西传统生态农业模式与技术主要有水旱轮作、复种和间作模式,精耕细作模式,循环利用培肥地力模式,生物防治病虫害技术等。上述优良传统,启示我省发展高效生态农业过程中,要讲究因地制宜、注重资源循环利用以及加强科技支撑和政府支持。 相似文献
10.
沙尘天气对新疆省英吉沙县农牧业生产的影响 总被引：1，自引：0，他引：1
位于新疆西南部的英吉沙县气候干燥,降水稀少,是沙尘天气的多发区和易发区,沙尘天气多发于春季和春夏之交,对当地农业生产和牧业养殖影响严重,提高灾害性天气预报预警服务以及加强生态环境治理和保护是降低损失、防范风沙的有效应对措施。 相似文献
11.
Gillespie R 《Science (New York, N.Y.)》2004,303(5656):356-359
Communities arising through adaptive radiation are generally regarded as unique, with speciation and adaptation being quite different from immigration and ecological assortment. Here, I use the chronological arrangement of the Hawaiian Islands to visualize snapshots of evolutionary history and stages of community assembly. Analysis of an adaptive radiation of habitat-associated, polychromatic spiders shows that (i) species assembly is not random; (ii) within any community, similar sets of ecomorphs arise through both dispersal and evolution; and (iii) species assembly is dynamic with maximum species numbers in communities of intermediate age. The similar patterns of species accumulation through evolutionary and ecological processes suggest universal principles underlie community assembly. 相似文献
12.
利用探空观测资料以及FY-2D气象卫星云图、多普勒天气雷达回波等非常规气象观测资料,采取天气学诊断分析方法,对2009年7月26日出现在广东清远市一次局地突发性暴雨过程进行了诊断分析。结果表明,副热带高压边缘的不稳定气流及南支槽前的上升运动是此次局地暴雨过程的天气尺度系统和大尺度环流背景;暴雨发生前大气不稳定能量不断积累,为中尺度系统形成创造了有利的环境条件;地形与降水有着密切的关系,中小尺度地形使近地面上升气流增强,造成了对流云团在该地不断生成和发展。 相似文献
13.
旨在探索如何构建一种生态与经济发展兼顾的建设用地管制分区工作体系。以扬州市为例,选择防洪、水土保持、生物保护、乡土文化保护和游憩安全5个要素构建区域多层次综合生态安全格局,利用神经网络CA模型模拟无生态约束下的区域城镇建设用地扩展格局,将二者耦合得到优先建设区、有条件建设区、调整建设区、限制建设区和禁止建设区,并为每类管制区编制相应的管制规则。结果表明:①利用景观安全格局与城镇建设用地扩展格局耦合来进行建设用地管制区划分,优先考虑生态环境保护,再进行建设用地的安排,实现了生态与经济的双赢;②通过调整建设区的划定,为地方政府提供了新增建设用地适宜调整的区域,在建设用地管制的基础上,给予地方政府充分的自主权。 相似文献
14.
针对淮北砂姜黑土地区土地种与养矛盾突出 ,粮、经、饲种植结构比例不当等问题 ,以提高经济、生态、社会综合效益为目标 ,选择农田种植紫花苜蓿以养为主及粮 -豆种养结合种植模式进行研究。结果表明 ,单作紫花苜蓿综合效益最高 ,豌豆 -水稻、蚕豆 -玉米分列第2、3位 ,各地可根据实际情况作为改良土壤、提高效益的措施进行推广。 相似文献
15.
Long-term studies of vegetation dynamics 总被引：1，自引：0，他引：1
By integrating a wide range of experimental, comparative, and theoretical approaches, ecologists are starting to gain a detailed understanding of the long-term dynamics of vegetation. We explore how patterns of variation in demographic traits among species have provided insight into the processes that structure plant communities. We find a common set of mechanisms, derived from ecological and evolutionary principles, that underlie the main forces shaping systems as diverse as annual plant communities and tropical forests. Trait variation between species maintains diversity and has important implications for ecosystem processes. Hence, greater understanding of how Earth's vegetation functions will likely require integration of ecosystem science with ideas from plant evolutionary, population, and community ecology. 相似文献
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水稻栽培适宜品种选择的知识模型 总被引：10，自引：1，他引：10
在阅读大量献资料及咨询农学专家的基础上，运用知识工程和系统建模方法，总结、归纳和提炼水稻品种选择与品种类型、生态环境和农作制度之间的动态关系，定量计算了水稻品种特征值与环境因子和生产需求之间的符合度，建立了适宜品种选择的量化知识模型。该模型可用于定量设计不同环境和生产条件下水稻种植的适宜品种。利用沈阳、南京、常德、昆明和广州5个代表性生态点的常年逐日气象资料、当地的生产条件以及24个不同品种资料，对品种选择知识模型进行了实例分析。结果表明模型预测结果与当地实际情况基本吻合。从而证明知识模型能有效地依据决策点的自然资源条件．对决策点适宜种植品种的选择具有较好的解释性和可靠性。 相似文献
19.
High-resolution climatic analysis and southwest biogeography 总被引：1，自引：0，他引：1
Neilson RP 《Science (New York, N.Y.)》1986,232(4746):27-34
Meteorologists and climatologists have produced significant new data on the fluid dynamics of the atmosphere, thus allowing biologists to examine more closely the cause-effect relation between the large-scale structure of the atmosphere and the dominant patterns of global biogeography. The inability to characterize the high-frequency variability of the weather has constrained such efforts. A method that allows year-to-year patterns of weather variability to be characterized in the contexts of global warming and cooling trends is applied in a combined analysis of long-term monthly weather records and data from an ecological monitoring project in southern New Mexico. The analysis suggests a cause-effect hypothesis of recent desertification in the North American Southwest. The links between the atmosphere and the biosphere are based on the fundamentally different responses to specific weather regimes of semidesert grasses with a C(4) photosynthetic pathway and desert shrubs with a C(3) photosynthetic pathway. The hypothesis appears to be of sufficient generality to explain the complex, but well-documented, floristic changes that have occurred in the same region since the last glacial maximum. 相似文献