Chen Jingliang, Zhang Yafeng, Liu Chao, Huang Lei
Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands/Shapotou Desert Research and Experiment Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China.
University of Chinese Academy of Sciences, Beijing, China.
Front Plant Sci. 2024 Oct 14;15:1466079. doi: 10.3389/fpls.2024.1466079. eCollection 2024.
Soil nematodes are the most abundant soil metazoans, occupying multiple trophic levels in the soil food web and playing an important role in soil function. Research on the biogeographic distribution patterns of soil nematode communities and their drivers has received greater attention. However, the distribution characteristics of soil nematode communities along the elevational gradient in the arid and semi-arid regions of Northwest China remain unclear. In this study, four elevational gradients (1750-1900, 1900-2100, 2100-2350 and 2350-2560 m) were established on Luoshan Mountain, Ningxia, an arid and semi-arid region in Northwest China, and soil nematodes in the soil layers of 0-10, 10-20 and 20-40 cm were investigated using the improved Baermann funnel method. The results revealed a monotonically decreasing trend in the total number of soil nematodes along the elevational gradient and soil layer depth, decreasing by 63.32% to 79.94% and 73.59% to 86.90%, respectively, while the interactions were not obvious. A total of 1487 soil nematodes belonging to 27 families and 32 genera were identified across the elevational gradient, with as the dominant genus, accounting for 10.43% of the total number of nematodes, and bacterivore nematodes as the main trophic groups, accounting for 32.39% to 52.55% of the relative abundance at each elevation, which increased with increasing elevation. Soil nematode community diversity, richness and maturity indices were relatively low at high elevation and decreased by 44.62%, 48% and 54.74%, respectively, with increasing soil layer depth at high elevations. Compared to low elevations, high-elevation soils experienced greater disturbance, reduced structural complexity and nutrient enrichment of the soil food web, and a shift in soil organic matter decomposition from bacterial to fungal pathways as elevation increased. Finally, redundancy analysis showed that soil pH, bulk density, soil moisture, soil organic carbon, available nitrogen, available phosphorus and available potassium were the main soil factors affecting the composition of soil nematode communities, which well explained the differences in nematode communities at different elevations and soil depths. This study can be used as basic information for further research on soil biota in this mountainous region, expanding our further understanding of the spatial ecology of soil nematodes in the arid and semi-arid mountain ecosystems.
土壤线虫是土壤中数量最多的后生动物，在土壤食物网中占据多个营养级，对土壤功能起着重要作用。土壤线虫群落的生物地理分布模式及其驱动因素的研究受到了更多关注。然而，中国西北干旱和半干旱地区土壤线虫群落沿海拔梯度的分布特征仍不清楚。在本研究中，在中国西北干旱和半干旱地区宁夏的罗山建立了四个海拔梯度（1750 - 1900米、1900 - 2100米、2100 - 2350米和2350 - 2560米），并采用改进的贝尔曼漏斗法对0 - 10厘米、10 - 20厘米和20 - 40厘米土层中的土壤线虫进行了调查。结果表明，土壤线虫总数沿海拔梯度和土层深度呈单调递减趋势，分别下降了63.32%至79.94%和73.59%至86.90%，而两者之间的相互作用不明显。在整个海拔梯度上共鉴定出1487条土壤线虫，分属27科32属，其中 为优势属，占线虫总数的10.43%，食细菌线虫为主要营养类群，在各海拔相对丰度占32.39%至52.55%，且随海拔升高而增加。高海拔地区土壤线虫群落多样性、丰富度和成熟度指数相对较低，且随高海拔土层深度增加分别下降了44.62%、48%和54.74%。与低海拔相比，高海拔土壤受到的干扰更大，土壤食物网的结构复杂性和养分富集程度降低，且随着海拔升高，土壤有机质分解途径从细菌途径向真菌途径转变。最后，冗余分析表明，土壤pH值、容重、土壤湿度、土壤有机碳、速效氮、速效磷和速效钾是影响土壤线虫群落组成的主要土壤因素，很好地解释了不同海拔和土壤深度线虫群落的差异。本研究可为该山区土壤生物群的进一步研究提供基础资料，拓展我们对干旱和半干旱山地生态系统中土壤线虫空间生态学的进一步认识。
