生态系统恢复后干热河谷植物叶片N、P、K含量及物种优势度的变化

以金沙江干热河谷生态系统为对象,通过对比恢复区与对照区(干扰区)的植物叶片N、P、K含量、比值及其与优势度的关系,研究了生态系统恢复对植物叶片化学计量特征的影响.结果表明：生态系统恢复显著降低了植物叶片的N、P含量以及P/K,对K含量无显著影响.其中,恢复区内植物叶片N、P、K含量均值分别为10.405、0.604和9.619 g·kg^-1,比对照区分别下降了16.9%、34.9%和4.7%.恢复区中植物优势度与叶片P含量间呈极显著负相关,而对照区植物优势度与叶片K含量的负相关关系最显著.生态系统恢复改变了N、P、K之间标度关系的斜率和截距.而恢复区与对照区同一物种间叶片N、P含量差别不显著.研究区植物叶片化学计量特征的改变主要是由群落物种替代引起的.

Changes of plant leaf N, P, and K concentrations and species dominance in an arid-hot valley after ecosystem restoration

Taking the arid-hot valley of Jinsha River, Southwest China as the object, a comparative study was made on the plant leaf N, P, and K concentrations and ratios as well as their relationships with species dominance in the restoration area and disturbed area, aimed to understand the effects of ecosystem restoration on the plant leaf stoichoimetric characteristics. Ecosystem restoration decreased the plant leaf N and P concentrations and P/K ratio significantly, but had lesser effects on the plant leaf K concentration. In restoration area, the plant leaf N, P, and K concentrations were averagely 10.405, 0.604, and 9.619 g·kg^-1, being 16.9%, 34.9%, and 4.7% lower than those in disturbed area, respectively. In restoration area, species dominance was significantly negatively correlated with plant leaf P concentration; while the species dominance in disturbed area had a significant negative correlation with plant leaf K concentration. Ecosystem restoration altered the slope and intercept of the scaling relationships among the plant leaf N, P, and K. No significant differences were observed in the leaf N, P, and K concentrations of the same plant species between restoration area and disturbed area, suggesting that the changes of plant leaf stoichiometric characteristics were mainly driven by the shift of species composition in the plant community.