Chen Zhifei, Zhou Junjie, Lai Shuaibin, Jian Chunxia, Chen Yang, Luo Yang, Xu Bingcheng
State Key Laboratory of Soil Erosion and Dryland Farming On the Loess Plateau, Northwest A&F University, Xinong Rd. 26#, Yangling, 712100, Shaanxi, People's Republic of China.
College of Life Sciences, Guizhou University, Guiyang, 550025, Guizhou, People's Republic of China.
Environ Sci Pollut Res Int. 2023 May;30(22):61913-61926. doi: 10.1007/s11356-023-26479-3. Epub 2023 Mar 18.
Unbalanced N and P input has substantially altered the relative importance of N and P limitation in grassland ecosystems, which resulted in profound impacts on species nutrient cycling, community structure, and ecosystem stability. However, the underlying species-specific nutrient use strategy and stoichiometric homeostasis in driving community structure and stability changes remain unclear. A split-plot N and P addition experiment (main-plot: 0, 25, 50, and 100 kgN hm a; subplot: 0, 20, 40, and 80 kgPO hm a) was conducted during 2017-2019 in two typical grasslands (perennial grass and perennial forb) communities in the Loess Plateau. The stoichiometric homeostasis of 10 main component species, species dominance, stability changes, and their contribution to community stability were investigated. Perennial legume and perennial clonal species tend to perform higher stoichiometric homeostasis than non-clonal and annual forb. Large shifts in species with high homeostasis vs. low homeostasis caused by N and P addition showed consistently profound impacts on community homeostasis and stability in both communities. In both two communities, species dominance performed significantly positive relationships with homeostasis under no N and P addition. P alone or combined with 25 kgN hm a addition strengthened species dominance-homeostasis relationship and increased community homeostasis due to increased perennial legumes. Under 50 and 100 kgN hm a combined with P addition, species dominance-homeostasis relationships were weakened, and community homeostasis decreased significantly in both communities, which was due to that increased annual and non-clonal forb suppressed perennial legume and clonal species. Our results demonstrated that trait-based classifications of species-level homeostasis offer a reliable tool in predicting species performance and community stability under N and P addition, and conserving species with high homeostasis is important to enhance semiarid grassland ecosystem function stability on the Loess Plateau.
氮磷输入不平衡极大地改变了草地生态系统中氮限制和磷限制的相对重要性，这对物种养分循环、群落结构和生态系统稳定性产生了深远影响。然而，驱动群落结构和稳定性变化的潜在物种特异性养分利用策略和化学计量稳态仍不清楚。2017年至2019年期间，在黄土高原的两个典型草地群落（多年生草本和多年生杂类草）中进行了一项裂区氮磷添加实验（主区：0、25、50和100 kgN·hm²·a；副区：0、20、40和80 kgP₂O₅·hm²·a）。研究了10种主要组成物种的化学计量稳态、物种优势度、稳定性变化及其对群落稳定性的贡献。多年生豆科植物和多年生克隆物种往往比非克隆和一年生杂类草表现出更高的化学计量稳态。氮磷添加导致高稳态物种与低稳态物种的大幅变化，对两个群落的群落稳态和稳定性均产生了持续深远的影响。在两个群落中，在不添加氮磷的情况下，物种优势度与稳态呈显著正相关。单独添加磷或与25 kgN·hm²·a的氮一起添加，由于多年生豆科植物增加，增强了物种优势度-稳态关系并提高了群落稳态。在50和100 kgN·hm²·a与磷一起添加的情况下，物种优势度-稳态关系减弱，两个群落的群落稳态均显著下降，这是由于一年生和非克隆杂类草的增加抑制了多年生豆科植物和克隆物种。我们的结果表明，基于性状的物种水平稳态分类为预测氮磷添加下的物种表现和群落稳定性提供了可靠工具，保护高稳态物种对于增强黄土高原半干旱草地生态系统功能稳定性至关重要。
