丹江口库区坡地保护中香根草种植对土壤螨的影响

Above-vegetation could influence the quantity and quality of food resouce into the soil food web. The nutrients in soil from vegetation may be altered with the increase of vegatigation age and diversity. The food web could be bottom-up regulated. Soil mites occupy multi-trophic levels, hence their community will response to these alternation. Understanding these mechanism will be helpful to understand the structure and function of soil food web. Vetiver grass (Vetiveria zizanioides) planting has been as an eco-engineering technology for anti-slide and anti-scour for a long time. It is more economical and practical to reinforce the stability of slope and beautify environment than concrete or masonry protective coverings. Now vetiver grass has been designated as the restored vegetation on the bank of Danjiangkou reservoir and the upstream rivers. This study was established on the slope in Danjiangkou reservoir, where the soil type is classified as red sandstone. The experiment of different planting ages and diverstiy modes of vetiver grass will be conducted to analyze the response of soil mite communtiy, using traditional taxon methods and molecular techniques. The physico-chemical and microbal characteristics will also be tested to explain the responses of soil mites.

地上植被会影响地下食物网营养物质的数量和质量。随着地上植被种植年限的增加以及植被多样性的提高，地下食物网的营养来源也会发生变化。土壤食物网具有自下而上的调控功能，螨在食物网占据多个营养位，因此螨群落将会在结构和功能上做出相应调整，理解这种响应的过程和机理对于理解食物网的结构和功能具有十分重要的现实意义和理论价值。植被种植是一种重要的水土保持方法，香根草作为水土保持植物已具有悠久的历史，并已被列为丹江口库区及上游水土保持指定草种。本课题将在丹江口水库库区周围红砂岩坡地进行，研究香根草不同种植年限下，和以香根草为主体多种植被混合种植模式下土壤螨的响应，分别从传统分类学和分子生物学两方面对螨群落结构进行探讨，并结合土壤理化环境和土壤微生物环境的变化，进一步分析和阐述产生这种响应的机理。

地上植被会影响地下食物网营养物质的数量和质量。随着地上植被种植年限的增加以及植被多样性的提高，地下食物网的营养来源也会发生变化。本课题在丹江口水库库区周围红砂岩坡地，研究了香根草不同种植年限下，和以香根草为主体多种植被混合种植模式下土壤螨、土壤微生物以及土壤理化性质的响应。采用传统分类学方法分析土壤螨类群丰度，采用真核生物DNA复合条形码技术分析土壤真核生物和土壤动物群落结构，采用氯仿熏蒸法和PLFA技术分析土壤微生物总量，并结合土壤理化环境的变化，进一步分析和阐述土壤螨和土壤食物网的响应机理。. 研究发现，该地区土壤螨的类群分布较为分散，共分离出64个类群，其中甲螨数量最多，占分离总数的80%以上。Punctoribates sp.、Xylobates sp.、Epilohmannia sp.、Tectocepheus sp.和甲螨若螨为各个处理中的常见优势类群。随着香根草种植年限的增加，土壤螨群落的多样性会发生相应的改变，呈现出先增加后减少的趋势，但最终恢复至对照水平。因此，香根草作为一种水土保持植物，虽然根部可以分泌化感物质，但并不会对土壤螨群落多样性产生不利影响。. 随着香根草种植模式复杂性的增加，土壤螨群落的丰度和多样性的变化并不明显。对螨群落进行排序后发现，四种生境之间存在着一定差异，也就是说地上植被多样性的改变，在一定程度上会影响土壤螨的群落结构，但两者之间联系并不紧密。DNA复合条形码聚类分析结果与螨群落分析结果一致。