放牧强度对高寒草地不同类群土壤动物的群落结构和多样性的影响

发布时间：2018-05-23 16:03

本文选题：放牧强度 + 高寒草地　；参考：《中国农业科学》2016年09期

【摘要】：【目的】明确放牧强度对高寒草地生态系统中不同类群土壤动物群落结构和多样性的影响。【方法】2014年9月在川西北红原县的西南民族大学"青藏高原生态保护与畜牧业高科技研究示范基地"内选取轻度放牧(light grazing,LG,15 sheep/hm~2)、中度放牧(medium grazing,MG,22 sheep/hm~2)、重度放牧(heavy grazing,HG,36 sheep/hm~2)及无放牧(对照)(no grazing,NG,0 sheep/hm~2)4个样地。使用Vortis便携式吸虫器采集地表小型节肢动物;用环刀采集0—5、5—10和10—15 cm层土样,每层采2份,分别用干漏斗法(Tullgren)和湿漏斗法(Baermann)分别分离土壤节肢动物和土壤线虫。【结果】主成分(PCA)分析结果表明,无放牧处理与其他放牧处理样地间的3类土壤动物群落结构均存在明显差异,说明放牧对土壤动物群落结构具有显著影响;而土壤线虫群落结构在3种放牧强度之间的差异最明显,其次是地表节肢动物,土壤节肢动物群落结构在3中放牧强度间的差异相对最小。3种放牧强度样地中的土壤节肢动物及土壤线虫的群落密度均显著高于无放牧处理样地(P0.01),而地表节肢动物群落密度则以轻度放牧样地最低。地表节肢动物的类群数随放牧强度增加而增加,但不同放强度间无显著差异(P0.05);Shannon多样性指数和Pielou均匀度指数均随放牧强度的增加呈先下降后增加的变化趋势,且以无放牧处理最高,中度放牧处理最低,不同放牧强度间具有显著差异(P0.05)。土壤节肢动物的类群数和Shannon多样性指数均呈先增加后下降的变化趋势,且均是中度放牧强度样地的多样性显著高于其他放牧强度样地(P0.05);而Pielou均匀度指数无明显变化趋势(P0.05)。土壤线虫的类群数以轻度放牧最高,Shannon多样性指数则是随放牧强度增加而下降,Pielou均匀度指数呈先下降后增加的趋势,以中度放牧最低,无放牧处理最高;单因素方差分析结果表明土壤线虫的多样性指数在各放牧处理间均有显著差异(P0.05)。多元回归分析结果表明地表和土壤节肢动物的密度和多样性指数与土壤化学性质呈显著相关(P0.05或P0.01),土壤线虫群落密度和多样性指数与土壤化学性质和放牧强度呈显著相关(P0.01)。【结论】不同类群土壤动物对放牧强度的响应不同,重度放牧有利于地表节肢动物,中度放牧利于土壤节肢动物,轻度放牧利于土壤线虫。因此在评价放牧对草地生态系统的影响时选取合适的土壤动物类群非常关键。
[Abstract]:[objective] to determine the effects of grazing intensity on the structure and diversity of soil fauna communities of different groups in alpine grassland ecosystem. [methods] Ecological conservation of Qinghai-Tibet Plateau, Southwest University for nationalities, Hongyuan County, Northwest Sichuan, September 2014 In the demonstration Base of High Technology Research on Conservation and Animal Husbandry, four plots were selected: light grazing light grazingng 15 sheep-hmmt2, moderate grazing medium grazingMG22 sheep-hmm2, heavy grazing heavy grazingn HGn36 sheep-hmm2) and no grazing (control no grazingng n0 sheephmm2). The small arthropods were collected by Vortis portable trematodes, and soil samples of 0-55-10 and 10-15 cm layers were collected with a ring knife, and 2 samples were collected from each layer. Soil arthropods and soil nematodes were isolated by dry funnel method (Tullgren) and wet funnel method (Baermann), respectively. There were significant differences between the three types of soil animal community structure between grazing treatment and other grazing treatments, which indicated that grazing had a significant effect on soil animal community structure. The difference of soil nematode community structure among the three grazing intensities was the most obvious, followed by the surface arthropod. The difference of soil arthropod community structure among three grazing intensities was the smallest. 3. The community density of soil arthropods and soil nematodes in three grazing intensity plots were significantly higher than that in ungrazed plots, while the surface node limb activity was significantly higher than that in ungrazed plots. The density of plant community was the lowest in light grazing plots. The number of species of arthropods increased with the increase of grazing intensity, but there was no significant difference among different intensities. Both Shannon diversity index and Pielou evenness index decreased first and then increased with the increase of grazing intensity. No grazing treatment was the highest, moderate grazing treatment was the lowest, and there was significant difference between different grazing intensities (P 0.05). The species number and Shannon diversity index of soil arthropods increased first and then decreased, and the diversity of all the plots with moderate grazing intensity was significantly higher than that of other grazing intensity plots, while the Pielou evenness index had no obvious change trend. The highest Shannon diversity index of soil nematodes in light grazing was that Pielou evenness index decreased first and then increased with the increase of grazing intensity, with moderate grazing being the lowest, and no grazing being the highest. The results of single factor variance analysis showed that the diversity index of soil nematodes was significantly different among different grazing treatments (P0.05). The results of multiple regression analysis showed that the density and diversity index of soil arthropods were significantly correlated with soil chemical properties (P0.05 or P0.01), and the density and diversity index of soil nematode community were correlated with soil chemical properties and grazing intensity. [conclusion] the responses of different groups of soil animals to grazing intensity were different. Heavy grazing was beneficial to surface arthropods, moderate grazing to soil arthropods and light grazing to soil nematodes. Therefore, it is very important to select suitable soil fauna groups when evaluating the effects of grazing on grassland ecosystem.
【作者单位】：西南民族大学生命科学与技术学院;
【基金】：国家自然科学基金(41371270、40801092) 中央高校优秀团队及重大孵化项目(2014NZYTD01) 四川省教育厅创新团队(14TD0049) 西南民族大学研究生创新型科研项目(CX2015SZ071)
【分类号】：S812.8

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