Abstract:

Soil protozoa, a kind of micro-single-celled eukaryotes in soil, are the key components of soil and play an important role in indicating the dynamic change of soil environmental quality. To understand the community composition, diversity and distribution pattern of soil protozoa at different elevations and their coupling relationship with environmental factors, a total of 9 plots at three different altitudes (low: LA, middle: MA, High: HA) were set up in July 2021 according to the geographical characteristics of Tibet Rezhen National Forest Park. The “non-submerged culture method”, “in vivo observation method” and “Wilbert protein silver method” were used to culture and morphologically identify soil protozoa. The results showed that a total of 76 species of soil protozoa were identified at three different altitudes in the study area, belonging to 2 phyla, 12 classes, 23 orders, 32 families and 46 genera. The dominant class was Zoomastigophorea, accounting for 22.37% of the total species. Among them, Dynaminidae prevailed at low altitudes, whereas Colpodea dominated at middle and low altitudes, which is related to the R-strategy growth pattern of Colpodea. There was no significant difference in the Shannon-Wiener diversity index, Pielou evenness index and Margalef abundance index among the three altitudes. There were differences in soil pH and water content between low and high altitudes. Co-occurrence network analysis showed that the relationship between the co-occurrence network nodes of the three soil protozoan species at different altitudes was mainly positive. The results of Mental analysis and redundancy analysis showed that total phosphorus was the main driving factor affecting the composition of soil protozoa community. The results of this study are helpful to understand the ecosystem changes of Rezhen National Forest Park in Tibet, and provide basic data support for ecological environment protection and sustainable development of the Qinghai-Tibet Plateau.

Key words: Rezhen National Forest Park, soil protozoa, community diversity, co-occurrence network, distribution pattern, environmental factors

摘要：

土壤原生动物是土壤中一类微型单细胞真核生物，是土壤的关键组成部分，对土壤环境质量动态变化具有重要的指示作用。为了解不同海拔土壤原生动物群落组成、多样性、分布格局及其与环境因子的耦合关系，于2021年7月根据西藏热振国家森林公园地理特征设置了3种不同海拔（低，LA；中，MA；高，HA）共9个样地，采用“非淹没培养法”、“活体观察法”和“Wilbert蛋白银法”对土壤原生动物进行培养和形态学鉴定。结果表明，研究区3种不同海拔共鉴定出土壤原生动物76种，隶属2门12纲23目32科46属，优势纲为动鞭纲（Zoomastigophorea），占总物种数的22.37%。其中，低海拔以动鞭纲为主，中高海拔以肾形纲（Colpodea）占据优势，这与肾形纲的生长方式为R-对策有关。Shannon-Wiener多样性指数、Pielou均匀度指数和Margalef丰富度指数在3种海拔段之间均无显著差异。土壤pH、含水量在低海拔和高海拔间存在差异。共发生网络分析显示，3个不同海拔土壤原生动物物种的共现网络节点间的关系主要为正相关。Mantel分析和冗余分析结果显示，总磷是影响土壤原生动物群落组成的主要驱动因子。该研究结果有助于了解西藏热振国家森林公园生态系统变化，为青藏高原生态环境保护和可持续发展提供基础数据支持。

关键词: 热振国家森林公园, 土壤原生动物, 群落多样性, 共现网络, 分布格局, 环境因子