布氏田鼠干扰对呼伦贝尔草原生态系统健康性的影响

    Effects of Disturbance of Brandt's Vole (Lasiopodomys brandtii) on Ecosystem Health in Hulunbuir Steppe

    • 摘要: 生态系统健康性评价是区域生态恢复与管理的重要依据。草原生态系统较为脆弱, 近年来在气候变化和人类活动的双重影响下, 呼伦贝尔草原生态系统健康性出现不同程度的下降趋势。在局部区域内, 相比于其他干扰类型, 小型啮齿动物干扰对草原生态系统健康性的影响逐渐凸显。以呼伦贝尔典型草原为研究区, 针对布氏田鼠不同干扰等级样地的鼠洞特征对草原生态系统健康性的影响进行分析。结果显示, 重度干扰阶段的健康性指数CVOR及其准则层4项指数变异均为最强, 其中活力指数变异系数最高, 为58.09%;活力指数与组织力指数在不同干扰阶段差异不显著, 草原基况指数及CVOR指数表现为对照样地及轻度干扰样地显著高于重度干扰样地, 恢复力指数表现为对照样地显著高于其他3个干扰程度样地; 鼠洞密度、洞口面积、鼠洞干扰指数与草原基况指数、恢复力指数、CVOR指数呈显著负相关关系, 与活力指数、组织力指数不存在显著相关关系。随着鼠洞干扰强度增加, CVOR指数及其准则层4项指数整体呈下降趋势, 而活力指数和组织力指数对鼠洞干扰响应不显著, CVOR指数整体变异性最小, 稳定性最强; 相比于鼠洞密度及洞口面积, 鼠洞干扰指数与CVOR指数及其准则层4项指数之间的关系更强, 可以作为一项综合评价鼠洞干扰强度的指标。研究结果可为我国北方草原生态系统健康性评价提供科学依据, 为草原区域管理人员采取有效措施改善退化生态系统健康状况提供重要参考。

       

      Abstract: The assessment of ecosystem health is a critical foundation for regional ecological restoration and management. Grassland ecosystems, being inherently fragile, have experienced varying degrees of decline in recent years due to the combined impacts of climate change and human activities. This is particularly evident in the Hulunbuir Steppe ecosystem. Among local disturbances, the effect of small rodent activity on grassland ecosystem health has become increasingly prominent compared to other types of disturbances. This study focuses on the typical steppe in Hulunbuir, analysing the impact of Brandt's vole burrow characteristics across different disturbance levels on grassland health. The findings show that variability in health indices and its 4 criterion layer indices is most pronounced at the severe disturbance stage, with the vigor index exhibiting the highest coefficient of variation at 58.09%. There are no significant differences in the vigor and organizational strength indices across disturbance stages. The grassland condition index and health index (CVOR) are significantly higher in un-disturbed and mildly disturbed sites compared to severely disturbed ones, while the recovery index is notably higher in un-disturbed sites than at all other disturbance levels. Burrow density, burrow entrance area, and burrow disturbance index are negatively correlated with grassland condition index, recovery index, and health index, showing significant correlations, however, no significant correlation was found with the vigor index or organizational strength index. As burrow disturbance intensity increased, the grassland health index and its 4 criterion layer indices generally declined, while the vigor index and organizational strength index showed no significant response. Among the indices, the CVOR index exhibited the least variability, showing the highest stability. Compared to burrow density and entrance area, the burrow disturbance index has a stronger correlation with the grassland health index, making it a more comprehensive indicator for assessing the intensity of burrow disturbances in the study of rodent damage to grasslands. The findings of this study provide a scientific basis for evaluating ecosystem health in northern China's grasslands, offering valuable insights for regional grassland managers in implementing effective measures to restore and improve the health of degraded ecosystems.

       

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