Yang Xiaoqin, Li Yue, Niu Bin, Chen Qiuyu, Hu Yilun, Yang Yibo, Song Lili, Wang Jianjun, Zhang Gengxin
State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Microb Ecol. 2022 Nov;84(4):1141-1153. doi: 10.1007/s00248-021-01901-w. Epub 2021 Oct 25.
Understanding the mechanisms underlying biodiversity patterns is a central issue in ecology, while how temperature and precipitation jointly control the elevational patterns of microbes is understudied. Here, we studied the effects of temperature, precipitation and their interactions on the alpha and beta diversity of soil archaea and bacteria in alpine grasslands along an elevational gradient of 4300-5200 m on the Tibetan Plateau. Alpha diversity was examined on the basis of species richness and evenness, and beta diversity was quantified with the recently developed metric of local contributions to beta diversity (LCBD). Typical alpine steppe and meadow ecosystems were distributed below and above 4850 m, respectively, which was consistent with the two main constraints of mean annual temperature (MAT) and mean annual precipitation (MAP). Species richness and evenness showed decreasing elevational patterns in archaea and nonsignificant or U-shaped patterns in bacteria. The LCBD of both groups exhibited significant U-shaped elevational patterns, with the lowest values occurring at 4800 m. For the three diversity metrics, soil pH was the primary explanatory variable in archaea, explaining over 20.1% of the observed variation, whereas vegetation richness, total nitrogen and the K/Al ratio presented the strongest effects on bacteria, with relative importance values of 16.1%, 12.5% and 11.6%, respectively. For the microbial community composition of both archaea and bacteria, the moisture index showed the dominant effect, explaining 17.6% of the observed variation, followed by MAT and MAP. Taken together, temperature and precipitation exerted considerable indirect effects on microbial richness and evenness through local environmental and energy supply-related variables, such as vegetation richness, whereas temperature exerted a larger direct influence on LCBD and the community composition. Our findings highlighted the profound influence of temperature and precipitation interactions on microbial beta diversity in alpine grasslands on the Tibetan Plateau.
理解生物多样性模式背后的机制是生态学的核心问题，然而温度和降水如何共同控制微生物的海拔分布模式却鲜有研究。在此，我们研究了温度、降水及其相互作用对青藏高原海拔4300 - 5200米梯度上高寒草原土壤古菌和细菌的α多样性和β多样性的影响。基于物种丰富度和均匀度对α多样性进行了检测，并用最近开发的局部对β多样性贡献（LCBD）指标对β多样性进行了量化。典型的高寒草原和草甸生态系统分别分布在4850米以下和以上，这与年平均温度（MAT）和年平均降水量（MAP）的两个主要限制因素一致。古菌的物种丰富度和均匀度呈现出随海拔降低的模式，而细菌的则无显著变化或呈U形模式。两组的LCBD均呈现出显著的U形海拔模式，最低值出现在4800米处。对于这三个多样性指标，土壤pH是古菌的主要解释变量，解释了超过20.1%的观测变异，而植被丰富度、总氮和钾/铝比则对细菌表现出最强的影响，相对重要性值分别为16.1%、12.5%和11.6%。对于古菌和细菌的微生物群落组成，湿度指数显示出主导作用，解释了17.6%的观测变异，其次是MAT和MAP。总体而言，温度和降水通过植被丰富度等局部环境和能量供应相关变量对微生物丰富度和均匀度产生了相当大的间接影响，而温度对LCBD和群落组成的直接影响更大。我们的研究结果突出了温度和降水相互作用对青藏高原高寒草原微生物β多样性的深远影响。
