Results 41 to 50 of about 22,799 (175)

松嫩平原土地盐碱化动态研究--以农安县为例

open access: yesShuitu Baochi Xuebao, 2004
结合地形图、遥感影像以及土壤专题图,提取松嫩平原典型代表区域——农安县近40年盐碱化土地面积动态变化信息,结合土地动态度模型和质心移动模型,对农安县近40年来盐碱化土地动态变化进行了较为全面的研究,分析了土地盐碱化动态的自然和人为驱动力因素,提出合理利用土地的建议。
何艳芬 张柏 马超群
doaj  

Community and population research of Tsuga longibracteata [PDF]

open access: yes, 2016
长苞铁杉(TsugalongibracteataCheng),是属于松科(Pinaceae),铁杉属(Tsuga)的第四冰期孑遗植物;主要分布在我国22°49'-28°33'N,107°12'-118°14'E之间;由于自身更新速度缓慢以及长期的砍伐利用,其地理分布相对狭小且呈零星分布,分布区和居群规模在逐渐缩小和下降,面临着灭绝的危险;本文针对分布在福建省内各县市的长苞铁杉群落进行了基本区系特征、物种多样性、种群生命过程、分布格局和生态位等方面的生态学研究,结论主要如下: 1、各样地长苞铁杉群落在科 ...
夏玉叶
core  

Scenarios and strategies for future‐proofing ecosystem management under climatic novelty

open access: yesConservation Biology, EarlyView.
Abstract Climate change is driving unprecedented declines in dominant, habitat‐forming foundation species across marine and terrestrial ecosystems globally. As climatic novelty becomes the norm, ecosystem reassembly will become increasingly common. Predicting and understanding these transitions, and their implications for future ecosystem functioning ...
Lauren T. Toth   +14 more
wiley   +1 more source

Industrial Upgrade Effects of Product Space Dynamic Evolution——in Case of China [PDF]

open access: yes, 2016
保持一国经济持续发展,提高国民收入水平,是经济学界所关注的重要课题。现有的比较优势理论认为,发展中国家可以通过充分发挥其比较优势,实现专业化生产,依靠产业分工和专业化经济,推动要素禀赋的内生转换,从而实现国家生产技术结构的升级和调整,内生地达到产业结构升级、高级化、合理化,推动经济的持续增长。但是“中等收入陷阱”现象对该理论的合理性和科学性提出了挑战,为什么光靠比较优势实现的专业化生产,无法实现内生的产业结构升级和持续的经济发展?显而易见,在解释和回答这个现实经济问题方面 ...
任天翔
core  

Advancing conservation breeding programs for marine invertebrates

open access: yesConservation Biology, EarlyView.
Abstract In the face of ecosystem change and biodiversity loss caused by climate change and other stressors, conservation breeding, or captive breeding, with the aim of reintroduction for wild population recovery, is an emerging tool for preventing species’ extinction and rehabilitating ecosystems.
Elora H. López‐Nandam   +3 more
wiley   +1 more source

2000-2020年昌吉州东部平原区地下水位埋深对土地利用及干旱时空演变的动态响应

open access: yesShuitu Baochi Xuebao, 2000
联合土地利用与覆被变化及气象干旱综合分析区域地下水位埋深变化及其动态响应关系,明晰地下水位埋深变化的阶段性主导因素,对地下水超采地区综合治理和地下水资源有效管控具有现实意义。选取昌吉州东部平原区2000-2020年78眼地下水监测井月尺度地下水位埋深数据资料及5期遥感影像数据并结合同期多尺度标准化降水蒸散发指数SPEI,分析不同时空尺度地下水位埋深对土地利用/覆被变化及SPEI的动态响应规律,探讨研究区土地利用变化与干旱变化趋势对地下水埋深变化的综合影响。结果表明 ...
刘坤, 高凡, 吴彬, 胡鑫
doaj  

近25 a 银川市城市化进程中热力景观格局演变分析 [PDF]

open access: yes, 2016
: Based on the Landsat images and statistical data,in this paper the urbanization process and thermal landscape dynamics of Yinchuan City were analyzed. The objectives of this study were as follows: ① To analyze the spatial and dynamic characteristics of
吕荣芳, 张建明, 王浩, 王鹏龙
core  

Overlap of nonbreeding wandering albatrosses with fisheries and implications for colony‐specific population trajectories at South Georgia

open access: yesConservation Biology, EarlyView.
Abstract Bycatch in fisheries is one of the most serious threats to pelagic seabirds, causing major population declines. Mitigation measures can reduce bycatch substantially, but many fisheries fail to apply best practices, and seabird mortality remains high.
V. Warwick‐Evans   +2 more
wiley   +1 more source

Study on microbial community responses and dissolved organic matter (DOM) transformations in coastal surface seawater amended with sedimentary DOM in Xiamen [PDF]

open access: yes, 2016
海洋沉积物是海水溶解有机质(Dissolvedorganicmatters,DOM)的重要来源。DOM作为海洋异养微生物生存的主要物质和能量来源,影响着微生物群落的结构,而微生物群落也同时影响着DOM的化学组成和最终命运。近年来,海洋沉积物DOM成为海洋生物地球化学领域的热点研究对象,但其生物可利用性一直存在争议,且沉积物DOM释放到上层水体后将如何影响微生物群落的结构也不清晰。为了研究沉积物DOM的生物可利用性,以及沉积物DOM与上层海水微生物群落之间的相互关系,本论文采集了厦门近岸沉积物表层DOM ...
周文楚
core  

Providing regular and frequent maps of losses and gains of farmland birds based on European monitoring data

open access: yesConservation Biology, EarlyView.
Abstract Knowledge of species distributions is essential for informing policies on nature conservation and restoration. However, updating them on a regular basis and doing so in a harmonized manner at the international level is difficult. The European Bird Census Council integrated national monitoring data covering 5 years to update farmland bird ...
Sergi Herrando   +54 more
wiley   +1 more source

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