青海祁连山国家公园高寒沼泽湿地土壤碳氮磷生态化学计量特征及其驱动因素

Ecological stoichiometry and driving factors of soil carbon, nitrogen, and phosphorus in the alpine marsh wetlands of Qinghai Qilian Mountain National Park

  • 摘要: 以青海祁连山国家公园高寒沼泽湿地区域的典型高寒沼泽湿地为研究对象,采集不同退化程度及土层深度下共54份土壤样品,采用单因素方差分析,评估退化程度与土层深度对碳(C)、氮(N)、磷(P)的质量分数w(g·kg−1)及其生态化学计量比(摩尔比)的影响特征,并结合多元回归和层次分割法探究地形、气候、土壤和植被因素对其生态化学计量特征的驱动机制.研究结果表明:1)随着湿地退化加剧,土壤有机碳(SOC)、总氮(TN)和总磷(TP)的w分别下降28.1%、36.6%和36.3%,C、P物质的量(n)比与N、P物质的量比下降,C、N物质的量比升高,各元素含量及计量比均随土层深度增加而降低;2)n(C)/n(N)与n(N)/n(P)表明该区域土壤存在N素限制,而n(C)/n(P)显示土壤中P素相对充足;3)土壤生态化学计量特征受多因素共同驱动,其中n(C)/n(N)主要受土壤性质影响(贡献率为35.19%),n(C)/n(P)受植被与土壤交互作用调控(29.12%、28.17%),n(N)/n(P)则主要受气候因素控制(34.78%).揭示了高寒沼泽湿地土壤生态系统养分元素循环特点,为理解高寒湿地生态系统碳氮磷耦合关系、评估湿地养分限制机制及其生态响应提供了重要依据.

     

    Abstract: Alpine marsh wetlands in the Qilian Mountain National Park of Qinghai are important components in the ecosystem of the Qinghai-Xizang Plateau. Ecological stoichiometries of soil carbon (C), nitrogen (N), and phosphorus (P) in this region are crucial to the understanding of alpine wetland ecological processes and nutrient cycling mechanisms. In this study, 54 soil samples with different degrees of degradation and from varied soil depths were collected. One-way ANOVA was used to evaluate effects of degradation degree and soil layer depth on C, N, and P content and their ecological stoichiometric ratios. Multiple regression and hierarchical segmentation methods were used to explore driving mechanisms of topography, climate, soil, and vegetation factors on ecological stoichiometric characteristics. As wetland degradation intensifies, soil organic carbon, total nitrogen, and total phosphorus content decrease by 28.1%, 36.6%, and 36.3%, respectively, with n(C)/n(P) and n(N)/n(P) ratios decreasing but n(C)/n(N) ratios increasing. Both element content and stoichiometric ratios were found to decrease with increasing soil depth. n(C)/n(N) and n(N)/n(P) ratios suggest nitrogen limitation in the soil, while the n(C)/n(P) ratio indicates relatively sufficient phosphorus. Soil ecological stoichiometric characteristics are driven by multiple factors, with n(C)/n(N) being primarily influenced by soil properties (35.19% contribution), n(C)/n(P) regulated by vegetation-soil interactions (29.12% and 28.17%), and n(N)/n(P) mainly controlled by climate factors (34.78%). In summary, nutrient element cycling characteristics in alpine marsh wetland ecosystems are identified, insights into the coupled relationships of C, N, and P in alpine wetland ecosystems, nutrient limitation mechanisms, and ecological responses are provided.

     

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