中生演替的生态

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 result indicated that: with the change of ecological factors and intensification of human activities,strong stability of grassland community structure of the local alpine meadow type along the highway in this region was found,proportion of medium xerophilous、rhizomous grass increased;alpine grassland community had relatively low stability,grassland community successed naturally to adapt to the new environment;...

结果显示：随着生态因子发生变化和人类活动的加剧，该区公路沿线高寒草甸类草地群落结构表现出了较强的稳定性，中旱生耐旱的根茎型禾草比重有所增加；高寒草原植物群落稳定性相对较差，草地群落为适应新的生境而发生了自然演替；沼泽化草甸亚类草地植物群落中群落伴生种的种类增加，优势种嵩草属植物在群落中的比重有所下降。

The reasons of iron ions content overproof in grade Ⅱ desalting water system,such as variation water quality,contamination of regenerant , operation adjustment of pretreatment system and switching operation of bed were discussed.

对二级脱盐水系统中铁离子含量超标的原因，如来水水质发生波动、再生剂受到污染、预处理系统操作调整、床体运行切换等进行了论述。

You were hired to drum up new business, so go and do it.

公司雇你招徕新业务，你就做你的事好了。