群落发生

Vegetation ecotype tend to be xerophyte and even hyper-xerophyte and finally replaced by annual plant. Community structure and species diversity also decrease as the ecological environment worsen, In this process, the height, coverage and biomass decreases by 56.6%、 80.8% and 74.2% respectively compared to steppe, and the indices of species richness, diversity and evenness decrease by 76.4%、 56.7% and 32.0%, but β diversity indices increase by 14.6 times, especially the decease of species gregariousness and the breadth and overlay of species Niche shows that grassland tend to be more sandy and vegetation retrogression succession take place.

其中，植被生态型逐渐由中旱生向旱生、超旱生过渡，并最终被一年生植被替代；群落结构及多样性呈明显递减规律，到严重沙化阶段，草群高度、盖度、生物量与典型草原相比，下降幅度分别达到56.6%、80.8%和74.2%；物种丰富度、多样性及均匀性分别降低76.4%、56.7%和32.0%；而群落β多样性增长14.6倍，特别是多年生物种群聚度降低和生态位宽度、生态位重叠值的下降，表明草地沙化，植被发生逆行演替。

The functional groups of protozoa community were damaged with the addition of fenvalerate. Bectivoresdetrivores were the tolerant species, and their predomination became more obvious with the increase of fenvalerate concentration.

加入氰戊菊酯后，原生动物的群落结构发生变化，各个功能类群均受到不同程度的损伤，一些食菌和碎屑者类原生动物对氰戊菊酯表现出较高的耐受性，随着氰戊菊酯浓度的增加，其在群落中的优势度更加明显。

According to the quantity occurred of the pests and the degree of the lawn destroyed, we have known the dominant species of the pest in the lawn. and the reason and dynamic of these species have been analyzed. It is important to the pests management of the Trifolium repens in the level of community.

同时，根据害虫的发生数量和对草坪的危害程度，从群落的角度确定了白三叶草坪上害虫的优势种，并分析了这些优势种产生的原因和动态，为白三叶草坪在群落水平上进行综合治理提供了重要的依据。

When single herbicide was used in the field for two years, the dominant species took place corresponding alternation. The community structure that originally mostly consisted of dicotyledonous weeds , such as Alopecurus aequalis sobol., etc.

通过连续几年的单一除草剂使用，烟田杂草的优势种群发生了相应变化，原来以看麦娘、马唐、稗草等单子叶杂草为主的群落结构演变成了现在以稗草、马唐及胜红蓟、两栖蓼、茴茴蒜为主的单、双子叶杂草混生结构，说明烟田施用除草剂会引起杂草群落结构变化，因此，在生产上则应注意除草剂的轮换使用。

The results showed that the human disturbance didn't change the dominant positions and roles of Pinus massoniana and Cunninghamia lanceolata in arbor. But it decreased the average diameter at breast height and average tree height and changed the species composition.

结果表明，人为干扰对乔木层马尾松Pinus massoniana和杉木Cunninghamia lanceolata优势种的主体地位和作用没有根本性的改变，但使群落平均胸径和平均树高降低，群落种类组成发生变化。

The influencing effects of grain production systems on the population of second generation of cotton bollworm in cotton were studied. The multi-harvest system provided cotton a good protection against cotton bollworm due to the corn plants in this system strongly attracted cotton bollworm adults when they were ovipositing, therefore reduced the density of cotton bollworm in cotton, compared with ton-grain system..

转Bt基因抗虫棉对棉田节肢动物多样性的影响用吸虫器取样和捕虫网取样两种方法，研究了转基因抗虫棉和化学防治对棉田节肢动物多样性的影响，发现转Bt基因棉棉田与非转基因常规棉棉田棉花害虫、自然天敌和中性节肢动物亚群落没有显著差异，而化学防治可以使各亚群落的个体数量、物种数量、多样性指数发生剧烈变化。

When a plant community vegetated on the ground, the roughness was changed because of the coverage and the height of plant, and the energy of wind because of the density and the interstitial-degree.

下垫面为植被群落时，风场分布发生改变，植被高度和盖度对下垫面粗糙度都有明显的影响，植被群落的密度以及断面疏透度对风能影响显著。

The results of the study on the plant communities among the stages of regressive succession indicated that the dominants and components of the communities changed with the aggravation of degradation, and the plant communities changed from the grass family-dominant community to the forbs-dominant one.

： 通过对高寒矮嵩草草甸不同退化演替阶段植物群落的研究显示，随着退化程度的加重，群落的组成和优势种等发生了很大的变化，植物群落从以禾本科为主，向以杂类草为主的群落演替。

The insect pest and natural enemy communities in Red Fuji apple orchard in Mouping District of Yantai City were quantitatively analyzed by multivariate analysis.

应用多元分析方法对烟台市牟平区红富士苹果园害虫与天敌群落进行了定量分析，采用最优分割法将苹果害虫与天敌群落的时序结构分为5个阶段，并分析了各个时序段害虫及天敌的发生特点。

The canonical correlations analysis proved that the outbreak intensity of the Japanses wax scale was significantly correlated with the characters of the plant community.

从群落学角度出发，通过群落特征指数和典型相关分析的方法，分析枣园植物群落、景观的结构特征以及日本龟蜡蚧发生程度与植物群落、景观多样性之间的关系。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。