尖峰岭热带天然林不同土层细菌群落多样性和组成的海拔变异规律

土壤微生物群落结构沿海拔梯度的变异是微生物生物地理学分异和群落空间分布的重要内容，然而，热带森林土壤微生物多样性及其群落特征的海拔模式尚不明确。研究海南省尖峰岭自然保护区0—20cm和20—40cm土壤细菌多样性和群落组成沿海拔梯度(400—1410m)的变化及其与环境因子的关系。结果表明：在0—20cm土壤微生物生物量碳、生物量氮和生物量磷随海拔升高(峰顶降低)而增加，20—40cm土壤微生物生物量碳、生物量氮和生物量磷随海拔升高呈先升高后降低趋势；整体上，变形菌门、放线菌门、酸杆菌门、拟杆菌门、厚壁菌门在0—20cm中占优势，丰度总和占该层细菌总量的88.17%;变形菌门、放线菌门、酸杆菌门、厚壁菌门、绿弯菌门在20—40cm中占优势，丰度总和占该层细菌总量的90.82%;随海拔增加，0—20cm细菌多样性线性减少，20—40cm细菌多样性变化不显著；沿海拔梯度，0—20cm细菌群落组成可分为低(409—1018m),中(1018—1357m)和高(1410m)三个海拔聚集群落，20—40cm细菌群落组成随海拔无显著性变化；两土层细菌多样性与土壤pH显著正相关，土壤细菌群落组成在0...

The altitudinal patterns of bacterial community diversity and composition at different soil depths in Jianfengling mountain tropical forest

The variation of soil microbial community structure along the altitudinal gradient is an important content of microbial biogeographic differentiation and community spatial distribution. However, the altitudinal pattern of soil microbial diversity and its community characteristics in tropical forests is not clear. This paper studied the changes of bacterial diversity and community composition and their relationship with environmental factors in 0-20cm and 20-40cm soil depths along the altitudinal gradient (400-1410 m) in Jianfengling Nature Reserve, Hainan Province. The results showed that the soil microbial biomass carbon, biomass nitrogen and biomass phosphorus increased with the elevation of 0-20cm (the peak decreased), and the soil microbial biomass carbon, biomass nitrogen and biomass phosphorus increased first and then decreased with the elevation of 20-40cm. On the whole, Proteobacteria, Actinomycetes, Acidobacteria, Bacteroidetes and Firmicutes are dominant in 0-20cm, and the total abundance accounts for 88.17% of the total bacteria in this layer; Proteobacteria, Actinomycetes, Acidobacteria, Firmicutes and Chloroflexi are dominant in 20-40cm, and the total abundance accounts for 90.82% of the total bacteria in this layer. With the increase of altitude, the bacterial diversity decreased linearly in 0-20cm, and that of 20-40cm did not change significantly. The bacterial community composition of 0-20cm can be divided into three communities at low altitude (409-1018 m), medium altitude (1018-1357 m), and high altitude (1410 m) and the bacterial community composition of 20-40cm has no significant change with altitude. There was a significantly positive correlation between bacterial diversity and soil pH in the two soil depths. The composition of soil bacterial community was mainly affected by mean annual temperature and pH at 0-20cm, and by mean annual temperature and soil organic carbon at 20-40cm. According to the Bray Curtis index, the similarity of bacteria in 0-20cm and 20-40cm soil depths decreased with the increase of geographical distance, and the similarity of bacterial community also decreased with the increase of environmental distance. In a word, the altitudinal pattern of soil bacterial diversity and community composition in Jianfengling is affected by soil depth, and the factors driving the change of bacterial community composition are different among soil depths. It is suggested that the soil microbial communities in 0-20cm and 20-40cm of tropical forests may have different response mechanisms under the background of future climate change.