■土壤微生物群落,包括生物土壤地壳微生物组,在水中发挥关键作用,碳和氮循环,生物风化,和沙漠生态系统的其他养分释放过程。然而,我们对微生物分布模式和生态驱动因素的了解仍然很少,尤其是对于奇瓦瓦沙漠。
■该项目研究了践踏扰动对表层土壤微生物群的影响,探索群落组成和结构,以及与奇瓦瓦沙漠生物群落中非生物和生物景观特征相关的模式。在乔纳达盆地15个长期生态研究地块的扰动和未扰动区域收集了复合土壤样品,新墨西哥州。跨域微生物群的微生物多样性(总细菌,蓝细菌,古细菌,和真菌)通过DNA扩增子metabarcode测序获得。序列数据与包括植被类型在内的景观特征有关,地貌,生态场地和状态以及土壤性质,包括砾石含量,土壤质地,pH值,和导电性。
■丝状蓝细菌在光自养群落中占主导地位,而变形细菌和放线菌在异养细菌中占主导地位。在土壤表面微生物群中,细菌是最丰富的古生菌,干旱适应的类群是土壤表面微生物群中最丰富的真菌。除了古菌的丰富度(p=0.0124),扰动样本在α多样性和群落组成方面与未扰动样本没有差异(p≥0.05),可能是由于缺乏频繁或有影响的干扰。植被类型和地貌显示出细菌丰富度的差异,古细菌,和蓝细菌,但不在真菌中。丰富度与土壤变量缺乏密切的关系。景观特征,包括母体材料,植被类型,地貌类型,生态遗址和国家,对相对丰度和微生物群落组成的影响比对α多样性的影响更强,尤其是蓝细菌和真菌。土壤质地,水分,pH值,电导率,地衣盖,多年生植物生物量与NMDS纵坐标中检测到的微生物群落梯度密切相关。
■我们的研究为景观特征之间的关系提供了第一个全面的见解,相关土壤特性,和奇瓦瓦沙漠中的跨域土壤微生物群。我们的发现将为土地管理和恢复工作提供信息,并有助于理解荒漠化和国家过渡等过程,这是世界各地旱地面临的紧迫的生态和经济挑战。
UNASSIGNED: Soil microbial communities, including biological soil crust microbiomes, play key roles in water, carbon and nitrogen cycling, biological weathering, and other nutrient releasing processes of desert ecosystems. However, our knowledge of microbial distribution patterns and ecological drivers is still poor, especially so for the Chihuahuan Desert.
UNASSIGNED: This project investigated the effects of trampling disturbance on surface soil microbiomes, explored community composition and structure, and related patterns to abiotic and biotic landscape characteristics within the Chihuahuan Desert biome. Composite soil samples were collected in disturbed and undisturbed areas of 15 long-term ecological research plots in the Jornada Basin, New Mexico. Microbial diversity of cross-domain microbial groups (total Bacteria, Cyanobacteria, Archaea, and Fungi) was obtained via DNA amplicon metabarcode sequencing. Sequence data were related to landscape characteristics including vegetation type, landforms, ecological site and state as well as soil properties including gravel content, soil texture, pH, and electrical conductivity.
UNASSIGNED: Filamentous Cyanobacteria dominated the photoautotrophic community while Proteobacteria and Actinobacteria dominated among the heterotrophic bacteria. Thaumarchaeota were the most abundant Archaea and drought adapted taxa in Dothideomycetes and Agaricomycetes were most abundant fungi in the soil surface microbiomes. Apart from richness within Archaea (p = 0.0124), disturbed samples did not differ from undisturbed samples with respect to alpha diversity and community composition (p ≥ 0.05), possibly due to a lack of frequent or impactful disturbance. Vegetation type and landform showed differences in richness of Bacteria, Archaea, and Cyanobacteria but not in Fungi. Richness lacked strong relationships with soil variables. Landscape features including parent material, vegetation type, landform type, and ecological sites and states, exhibited stronger influence on relative abundances and microbial community composition than on alpha diversity, especially for Cyanobacteria and Fungi. Soil texture, moisture, pH, electrical conductivity, lichen cover, and perennial plant biomass correlated strongly with microbial community gradients detected in NMDS ordinations.
UNASSIGNED: Our study provides first comprehensive insights into the relationships between landscape characteristics, associated soil properties, and cross-domain soil microbiomes in the Chihuahuan Desert. Our findings will inform land management and restoration efforts and aid in the understanding of processes such as desertification and state transitioning, which represent urgent ecological and economical challenges in drylands around the world.