Guangdong Provincial Key Laboratory of Applied Botany and Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.
College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China.
Glob Chang Biol. 2024 Feb;30(2):e17201. doi: 10.1111/gcb.17201.
Globally increased nitrogen (N) to phosphorus (P) ratios (N/P) affect the structure and functioning of terrestrial ecosystems, but few studies have addressed the variation of foliar N/P over time in subtropical forests. Foliar N/P indicates N versus P limitation in terrestrial ecosystems. Quantifying long-term dynamics of foliar N/P and their potential drivers is crucial for predicting nutrient status and functioning in forest ecosystems under global change. We detected temporal trends of foliar N/P, quantitatively estimated their potential drivers and their interaction between plant types (evergreen vs. deciduous and trees vs. shrubs), using 1811 herbarium specimens of 12 widely distributed species collected during 1920-2010 across China's subtropical forests. We found significant decreases in foliar P concentrations (23.1%) and increases in foliar N/P (21.2%). Foliar N/P increased more in evergreen species (22.9%) than in deciduous species (16.9%). Changes in atmospheric CO concentrations ( ), atmospheric N deposition and mean annual temperature (MAT) dominantly contributed to the increased foliar N/P of evergreen species, while , MAT, and vapor pressure deficit, to that of deciduous species. Under future Shared Socioeconomic Pathway (SSP) scenarios, increasing MAT and would continuously increase more foliar N/P in deciduous species than in evergreen species, with more 12.9%, 17.7%, and 19.4% versus 6.1%, 7.9%, and 8.9% of magnitudes under the scenarios of SSP1-2.6, SSP3-7.0, and SSP5-8.5, respectively. The results suggest that global change has intensified and will progressively aggravate N-P imbalance, further altering community composition and ecosystem functioning of subtropical forests.
全球范围内氮（N）磷（P）比（N/P）的增加会影响陆地生态系统的结构和功能，但很少有研究涉及亚热带森林中叶 N/P 的时间变化。叶 N/P 表示陆地生态系统中 N 对 P 的限制。量化叶 N/P 的长期动态及其潜在驱动因素对于预测全球变化下森林生态系统的养分状况和功能至关重要。我们使用 1920-2010 年间在中国亚热带森林中采集的 12 个广泛分布物种的 1811 个标本，检测了叶 N/P 的时间趋势，定量估计了其潜在驱动因素及其与植物类型（常绿与落叶，乔木与灌木）之间的相互作用。我们发现叶 P 浓度（23.1%）显著下降，叶 N/P 增加（21.2%）。常绿物种的叶 N/P 增加（22.9%）比落叶物种（16.9%）更多。大气 CO 浓度（ ）、大气 N 沉降和年平均气温（MAT）的变化主要导致常绿物种的叶 N/P 增加，而 、MAT 和蒸气压亏缺则导致落叶物种的叶 N/P 增加。在未来的共享社会经济途径（SSP）情景下，增加的 MAT 和 将继续导致落叶物种比常绿物种的叶 N/P 增加更多，分别为 SSP1-2.6、SSP3-7.0 和 SSP5-8.5 情景下的 12.9%、17.7%和 19.4%，而 SSP1-2.6、SSP3-7.0 和 SSP5-8.5 情景下的 6.1%、7.9%和 8.9%。研究结果表明，全球变化加剧并将逐步加剧 N-P 失衡，进一步改变亚热带森林的群落组成和生态系统功能。
