甘南亚高寒草甸冷暖季土壤纤毛虫群落对坡向的响应

Response of soil ciliates community in cold and warm seasons to slope aspects of subalpine meadow in Gannan

为了揭示坡向变化对土壤纤毛虫群落的影响,于2015年4月和7月,对甘南亚高寒草甸不同坡向的土壤纤毛虫群落及环境因子进行了研究。结果表明:春季鉴定出土壤纤毛虫97种,隶属于9纲、17目、32科、50属,夏季鉴定出土壤纤毛虫141种,隶属于9纲、18目、32科、55属;随着土层深度变化,土壤纤毛虫群落有明显的表聚性;春季土壤纤毛虫密度和类群数明显低于夏季,不同坡向则是春季的阳坡和夏季的西坡土壤纤毛虫密度最高;从5个坡向的土壤环境因子来看,阴坡的土壤含水量和养分含量较高、pH和温度较低,阳坡则与其相反,西坡环境因子较适中;RDA分析结果表明,甘南亚高寒草甸不同类群的土壤纤毛虫对环境因子的响应不同,大多数类群适宜西坡水热和营养适中的生境状况,篮口科(Nassulidae)、篮环科(Cyrtolophosidae)适宜全磷丰富的半阳坡,康纤科(Cohnilemebidae)则适应含水量高、营养丰富的阴坡。

In order to reveal the influence of slope aspects on soil ciliates community, the soil ciliates communities and environmental factors were investigated in subalpine meadow of Gannan in April and July of 2015. The results showed that 97 species of ciliates were identified in spring, belonging to 9 classes, 17 orders, 32 families and 50 genera, and 141 species of soil ciliates were identified in summer, belonging to 9 classes, 18 orders, 32 families and 55 genera. Soil ciliate community had obvious surface aggregation. Soil ciliates density and taxa were significantly lower in spring than in summer, and the density of soil ciliates was the highest on the south slope in spring and on the west slope in summer. Soil water content and nutrient content were higher, and pH and soil temperature were lower on the north slope, while the situation was opposite on the south slope, and the environmental factors were moderate on the west slope. RDA analysis showed that the response of soil ciliates was different to environmental factors in subalpine meadows of Gannan. Most of taxa were suitable for the moderate habitat conditions of water, heat and nutrient on the west slope. Nassulidae and Cyrtolophosidae adapted to the condition of rich soil total phosphorus on the southwest slope, while Cohnilemebidae adapted to the condition of high soil water content and rich nutrients on the north slope.