Grassland degradation affects the response of soil bacterial and plant but not fungal diversity to nitrogen addition
Grassland degradation affects the response of soil bacterial and plant but not fungal diversity to nitrogen addition
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DOI：
10.1111/1365-2745.14179
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发表时间：
2023-08
影响因子：
5.5
通讯作者：
Yufan Wang;Hongjin Zhang;Guo-Xu Yu;Lizheng Dong;Jianyong Kang;Wen Wang
中科院分区：
文献类型：
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作者：
Yufan Wang;Hongjin Zhang;Guo-Xu Yu;Lizheng Dong;Jianyong Kang;Wen Wang
1. 大气氮沉降对天然草原的植物和土壤微生物群落构成严重威胁，从而对生态系统功能产生影响。然而，大气氮沉降的影响可以通过草地退化来调节，这里定义为土壤侵蚀、土壤养分下降和植物多样性丧失，这已成为这些生态系统功能的全球威胁。目前人们对植物和土壤微生物群落对氮沉降的反应是否随草地退化而变化仍知之甚少。 2. 我们在内蒙古的四个站点进行了为期 9 年的多水平（0、10、20、30、40、50 g N·m−2 年−1）氮富集实验。采用复合指数（草地退化指数）评价草地退化情况，将草地分为未退化、中度退化、严重退化和极度退化四类。为每个类别选择一个站点，然后在每个站点内设置三个重复。 N以尿素的形式添加。 3.我们首先观察到，退化草地土壤细菌多样性对施氮的响应强于未退化草地，而土壤真菌多样性的响应不受退化影响。同时，与非退化草地相比，氮富集对退化草地植物多样性的影响更弱。不同退化状态草地土壤微生物多样性和群落组成对施氮响应的控制因素不一致。土壤pH值是非退化草原的主要驱动因素，植物群落组成成为退化草原的重要驱动因素。 4.合成。我们的研究结果强调，草地退化影响了细菌和植物群落对氮沉降的响应，并为退化草地生物多样性的管理和保护提供了新信息。
1. Atmospheric nitrogen (N) deposition poses serious threats to plant and soil microbial communities in natural grasslands, which can have consequences on ecosystem functioning. However, the effects of atmospheric N deposition can be modulated by grassland degradation, defined here as soil erosion, soil nutrient decline and loss of plant diversity, which has become a global threat to the functioning of these ecosystems. It remains poorly understood whether the responses of plant and soil microbial communities to N deposition vary with grassland degradation. 2. We conducted a 9‐year multilevel (0, 10, 20, 30, 40, 50 g N m−2 year−1) N enrichment experiment at four sites in Inner Mongolia, China. We evaluated grassland degradation using a compound index (grassland degradation index) and classified grassland sites into four categories: non‐degraded, moderately, severely and extremely degraded grasslands. One site was selected for each category, and then three replicates were set up within each site. N was added in the form of urea. 3. We first observed that the response of soil bacterial diversity to N addition was stronger in degraded grasslands than in non‐degraded grasslands, whereas the response of soil fungal diversity was not affected by degradation. Meanwhile, N enrichment had a weaker impact on plant diversity in degraded grasslands compared to non‐degraded grasslands. The controlling factors that affected the responses of soil microbial diversity and community composition to N addition were inconsistent among grasslands with different degradation status. Soil pH was the main driver in non‐degraded grasslands, and plant community composition became an important driver in degraded grasslands. 4. Synthesis. Our findings highlighted that grassland degradation affected the response of bacterial and plant communities to N deposition and provided new information for the management and conservation of biodiversity in degraded grasslands.