高寒草甸对旅游踩踏的抗干扰响应能力

以香格里拉石质干草甸和林缘中生草甸为研究对象,结合野外踩踏模拟实验,通过方差分析和回归分析确定2种植物群落对踩踏干扰的响应规律,及其耐踩踏能力和恢复力。结果表明,1)随着踩踏强度增加,2种生境的草甸群落相对盖度均逐渐降低,但是林缘中生草甸的下降更明显;2)石质干草甸群落的耐踩踏能力在708次左右,林缘中生草甸群落约为551次;3)踩踏1年后,石质干草甸群落的相对盖度恢复了66.5%,而林缘草甸群落则恢复了86.1%,后者表现出更强的恢复能力;4)石质干草甸主要物种的耐踩踏能力介于390~578次之间,林缘中生草甸主要物种的则介于282~463次之间。

Tolerance of alpine meadows to human trampling

To quantify the relationship between trampling and vegetation damage, field simulations with standardized methodology were conducted to determine the resistance and resilience of alpine meadow in Shangri-La for two communities: dry meadow and mesophytic meadow. Vegetation parameters were measured in lanes subject to control (no trampling), 50, 100, 200, 500 and 700 passes at six sites prior to trampling, immediately after trampling, 2 weeks and 1 year after trampling. Relative vegetation cover (RVC) was calculated for each trampling treatment. RVC comparisons for each path and community were done by Analysis of Variance (ANOVA), and regression models were used to calculate the coefficient of resistance. 1) RVC decreased with increasing trampling intensity, although the curves of interpolated RVC values for all possible trampling intensities between 0 and 700 were similar, while the mean RVC was significantly different only at the 700 passes. 2) The resistance indices (number of passes resulting in 50% reduction in RVC) were around 708 passes for the dry meadow and around 551 passes for the mesophytic meadow, indicating these two communities were high resistance vegetation types as compared with other mountain meadow communities tested around the world. 3) One year after trampling, the RVC recovered 66.5% in dry meadow and 86.1% in mesophytic meadow, suggesting that the latter showed stronger resilience than the former. 4) Resistance of the main species were around 390-578 passes for the dry meadow and 282-463 passes for the mesophytic meadow, showing the resistance of different component species varied greatly under different environmental conditions. This study demonstrates that high elevation vegetation communities vary in their resistance and resilience to disturbance. Results such as those obtained here can underpin management decisions, and support long term monitoring programs of trampling impacts.