克氏针茅草原植物叶片性状对放牧强度的响应

放牧干扰是影响草地植物性状的方式之一,植物叶片性状能够客观反映植物对生长环境的适应性.本文以呼伦贝尔克氏针茅草原不同放牧强度的样地为研究区,探讨叶片性状间的相互关系及在不同放牧梯度上和不同生活型功能群之间的变化规律.结果表明:克氏针茅草原植物的主要叶片性状在不同生活型植物之间差异均不显著,但是各个性状之间的相关性较强.在放牧梯度上,重度放牧样地上叶片磷含量和氮磷比值与中度放牧区和轻度放牧区有显著差异;在生活型功能群分类中,放牧对多年生杂草的叶片磷含量和氮磷比值有显著影响,表明多年生杂草对放牧较为敏感,重度放牧改变了植物养分利用策略.合理放牧可以改善克氏针茅草原植物养分性状并有利于遏制草原的退化.

Response of plant leaf traits to grazing intensity in Stipa krylovii steppe.

Grazing disturbance is one of the ways to influence plant traits, and plant leaf traits actually reflect the adaptability of plants to the environment. In this study, taking Stipa krylovii steppe under different grazing intensities in Hulunbuir as research area, the relationships of leaf traits and the variation of plant traits among plant life-form functional groups was investigated. Results showed that plant traits with different life-forms had no significant difference in S. krylovii steppe. However, the relationships between plant traits were strongly correlated. The leaf phosphorus content (LPC) and the ratio of nitrogen and phosphorus (N/P) in the heavy grazing treatment had significant difference from those in the moderate grazing and the light grazing treatments. For different life-form functional groups, grazing disturbance had significant effect on LPC and N/P in the perennial forbs, indicating the perennial forbs were sensitive to grazing, and the plant nutrient utilization strategy was changed by heavy grazing. It was suggested that reasonable grazing could improve the nutrient traits of plants and restrain the degradation in S. krylovii steppe.