演替

The seasonal variability of PBSi has a close link to the change of phytoplankton community structure.

PBSi含量的季节差异与浮游植物群落结构的演替有着密切关系。

Nevertheless, researchers of the Pleistocene epoch have developed

这一序列演替所依据的，主要是一系列与冰川期和间冰期并不直接相

On the basis of pollen analysis of surface sample in North China, polynomial function analysis method was applied to establish pollen climate response surface of Pinus, Betula, Quercus, Artemisia, Chenopodiaceae, Compositae, Picea, Ephedra, Gramineae in North China, therefore an easy and applicable method for reconstructing palaeoclimate and palaeoenvironment with data of fossil pollen was founded; Multi-analysis method was applied to analyse the principal elements of surface sample pollen in central Inner Mongolia Steppe, the assemblages of surface sample pollen in steppe area and its relationship with vegetation type were discussed with helps from spore-pollen analysis of a peat section in Chasuqi, Inner Mongolia and 〓C chronometer, fossil pollen data were obtained with high resolution on the peat section in Chasuqi. Vegetation succession and environmental changes since Holocene at resolution of 70 years were primarily reconstructed in south Mount Daqingshan and Plain Tumete. The changes in the area were copmared with those in the neighbouring areas during the same period. It was found that Holocene environmental change had undergone the following stages: cold-arid, temperate-wet, warm-wet, temperate-arid and cold-arid, and the climatical optimum period occurred in 5000-4100 aB.

本文在对中国北方表土花粉研究的基础上，采用多项式函数回归方法建造了中国北方松属、桦属、栎属、蒿属、藜科、菊科、云杉属、麻黄属、禾本科等的花粉——气候趋势面，从而为利用化石花粉资料直接恢复古气候、古环境提供了一种方便易行的方法；采用多元分析方法对内蒙古中部草原区表土花粉进行了主成分分析，探讨了草原区表土花粉组合的规律及与植被类型的关系；本文还应用孢粉分析方法，结合〓C测年技术，通过内蒙古中部察素齐泥炭剖面高分辨率的化石花粉数据，初步恢复了大青山山地南部及土默特平原地区分辨率为70年的全新世以来植被演替和环境变迁的状况，并与邻近地区的全新世古气候、古环境进行了对比研究，研究发现，本区域全新世古环境的变迁序列基本上可以与周围地区及华北地区进行对比，其环境变迁经历了凉干～温湿～暖湿～温干～凉干的变化，且气候最适宜期出现在5000～4100aB.P。

Species-pairs were positive correlation,including 10 species-pairs were higher significant positive correlation and 24 speciespairs were significant positive correlation, and 263 species-pairs were negative correlation, including 8 species-pairs were higher significant negative correlation and 28 species-pairs were significant negative correlation, which were tested by Spearman＇ s rank correlation coefficient.

正负相关比为0.7643，显著种对占总对数的15.05%，群落优势种种间多呈不显著关联。2）按照31个建群种和优势种对环境的适应方式和主导生态因素，它们被划分为2个生态种组：芦苇组和早熟禾组。3）关帝山撂荒地植物群落以退耕还林的先锋物种为主，表明植物群落处于森林植被恢复的初期演替阶段。

Table 3 The regression equation , correlation coefficient ,and increased percentage of 30 soybean cultivars with years of released

表3 30个大豆品种随育成年代演替某些农艺性状的回归方程，相关系数及增长的百分率

Increase of fragmentation degree is also shown that the increase of vegetation succession and revegetation's variety.

破碎化程度的增高也表明了复垦地的植被演替与恢复过程的多样性在不断增加。

The ecological significance of the different responses of seedling regeneration to light environmental heterogeneity for biodiversity maintenance in forest, forest succession and revegetation were discussed.

接着从森林物种多样性维持、森林演替和植被恢复的角度探讨了幼苗更新对光环境异质性不同响应的生态学意义。

Degradation strongly influences the presence of tolerative species in the seed bank and the vegetation, but it were less role to ruderal species.

我们认为：1土壤种子库拥有大量早期演替阶段的物种；2条件耐受性物种通常缺乏种子库；3退化强烈的影响了条件耐受性物种，而对杂草性物种的影响不大；4土壤种子库对青藏高原高寒草甸的恢复具有重要的贡献。

It is important to understand the rule of evolvement and substitution of human civilization,and know the characteristics of the times of the currert human.

正确认识人类文明演变和演替的规律对任何一个国家和民族来说都是至关重要的。

The results indicated:During the course of vegetation natural recovery, there are different stage of secondary sere at different degree of degraded lands, that is secondary herbosa; secondary scrub; masson pine coniferous forest; conifer and broad-leaved mixed forest; every green broad-leaved forest.

本项研究从比较生态学入手，分析了千岛湖地区退化森林生态系统不同植被恢复措施，即：自然恢复、人工促进自然恢复和人工恢复措施下的群落生态变化，比较了不同措施之间的生态响应差异，研究结果表明：①在植被自然恢复过程中，由于生态系统退化程度的不同，存在草灌丛、灌丛、马尾松林、混交林和常绿阔叶林整个演替序列。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了