放牧高寒嵩草草甸的稳定性及自我维持机制

以空间代时间,在＂三江源＂和中国科学院海北高寒草甸生态系统研究站地区,将处于不同退化阶段的高寒嵩草草甸作为研究对象,进行了其植物群落、地表状况、草毡表层厚度、根土比和水分渗透速率的演替过程与规律研究,以明晰放牧高寒嵩草草甸退化过程中其系统稳定性及自我维持机制。结果表明,高寒嵩草草甸虽然结构简单,但在长期适应寒冷气候进化过程中形成了低矮化、细绒化和草毡表层加厚、极度发育等一系列特殊的稳定性维持机制,可以承受一定范围内的人为干扰和气候波动,具有较高的系统稳定性与自我调控能力,但系统遭到破坏后的恢复能力极差。今日高寒草甸的大面积退化,是人类所赋加于草地的承载力远超过其承载力阈值而导致系统稳定性崩溃的结果。

System Stability and its Self-maintaining Mechanism by Grazing in Alpine Kobresia Meadow

The Alpine Kobresia Meadow Ecosystems at the different stage of degradation in the Haibei Alpine Meadow Ecosystems Research Station and the Three Rivers Source Region were studied to reveal the plant communities, surface conditions, mattic peipedon thickness, roots and soil ratio, and moisture saturation ratio, so as to distinct the system stability and its self-maintaining mechanism in the course of the degradation in alpine meadow. The results showed that the alpine Kobresia meadow system had performed special mechanism to maintain its stability in the long-term evolution process although it had a simple structure. So it could bear the man-made interferences and climate fluctuations to some extents, and had higher ability of controlling and resuming system, as it maintained its system stability through lowing, villiform and mattic growth. But the alpine Kobresia meadow system had a very bad recovering ability after the system destroyed. Nowadays, the reason for the degeneration of alpine meadow in large areas was that the carrying capacity endowed by human had exceeded the capability threshold.