Trophic group specific responses of alpine nematode communities to 18 years of N addition and codominant plant removal
Trophic group specific responses of alpine nematode communities to 18 years of N addition and codominant plant removal
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DOI：
10.1007/s11104-023-06281-3
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发表时间：
2023-10
期刊：
影响因子：
4.9
通讯作者：
Rachel M. Shepherd;L. Brigham;C. P. B. de Mesquita;K. Gattoni;E. Gendron;Philip G. Hahn;Steven K. Schmidt;Jane G. Smith;K. Suding;D. Porazinska
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作者：
Rachel M. Shepherd;L. Brigham;C. P. B. de Mesquita;K. Gattoni;E. Gendron;Philip G. Hahn;Steven K. Schmidt;Jane G. Smith;K. Suding;D. Porazinska
研究背景与目的人为氮沉降可以改变土壤生态地球化学和植物群落结构，这两个方面对土壤生物区系都至关重要。然而，了解养分资源和植物对土壤群落之间的关系的相对影响一直受到阻碍，缺乏这两个因素的实验操作。我们假设，土壤线虫群落的结构主要是通过N添加通过整体增加丰度，减少多样性，和成分的变化，以占主导地位的r-选择的食菌线虫。相比之下，我们预计植物的影响是不太明显，并限制线虫直接与plantsMethodsWe使用了长期（18年）的实验，在潮湿的草甸高山苔原，涉及N的添加和共显性植物（nitrophilicDeschampsia cespitosa和nitro-sensitiveGeum rossii）去除。我们通过18 S rRNA metabarcoding线虫社区的特点，并使用土壤生物地球化学，植物，和微生物变量，以确定塑造他们的community.ResultsThe的因素增加整体线虫丰度，减少多样性，并影响所有线虫营养组的组成。总体而言，线虫群落转变为优势的食菌线虫类群适应富氮环境。这种转变的可能驱动力增加土壤硝酸盐和pH值较低。共显性植物的直接影响更为有限，只有在Geum rossiiappearing影响nematode responses.ConclusionOverall的变化，线虫群落在N-有限的高山生态系统中是高度敏感的N可用性的增加，无论共显性植物的N偏好的性质。由此产生的线虫群落重组可能意味着整个高山景观土壤功能的未来变化。
Background and AimsHuman-driven nitrogen (N) deposition can alter soil biogeochemistry and plant communities, both critical to soil biota. However, understanding the relative impact of the relationship between nutrient resources and plants on soil communities has been hindered by a lack of experimental manipulations of both factors. We hypothesized that soil nematode communities would be structured predominantly by N addition via overall increased abundance, decreased diversity, and compositional shifts to dominance of r-selected bacterial-feeding nematodes. In contrast, we expected plant effects to be less evident and restricted to nematodes directly associated with plants.MethodsWe used a long-term (18-yrs) experiment in moist meadow alpine tundra involving N addition and codominant plant (nitrophilicDeschampsia cespitosaand nitrogen-sensitiveGeum rossii) removal. We characterized nematode communities via 18S rRNA metabarcoding and used soil biogeochemistry, plant, and microbial variables to determine factors shaping their communities.ResultsThe N addition treatment increased overall nematode abundance, decreased diversity, and affected the composition of all nematode trophic groups. Overall, nematode communities shifted to dominance of bacterial-feeding nematode taxa adapted to N-enriched environments. The likely drivers of this shift were increased soil nitrate and lower pH. The direct effects of codominant plants were more limited, with only changes inGeum rossiiappearing to affect nematode responses.ConclusionOverall, nematode communities in N-limited alpine ecosystems are highly sensitive to increases in N availability, irrespective of the nature of N preferences of codominant plants. The resulting nematode community restructuring could signify future shifts in soil functioning throughout alpine landscapes.