云南石林喀斯特露石径流输出及其影响因素探究

A Study of Runoff of Karst Rock Outcrops and Its Influencing Factors in Shilin,Yunnan Province

喀斯特露石具有重要的生态功能,但关于露石承接降水后的石面径流及其影响因子研究仍然很少。本实验选择云南石林的石漠化、人工林、原生林生态系统,布设露石径流收集装置,收集并测量不同降雨事件后的露石石面径流,测定露石承接降水面积和粗糙度。结果表明:(1)在3.92 mm到72.31 mm的降雨范围内,露石承接降雨量与露石径流量间存在极显著的正相关关系。(2)降雨量,林冠覆盖,露石粗糙度均影响露石径流输出。降雨量与露石径流深成显著正相关关系;石漠化生态系统的露石承接降雨量和露石径流输出显著高于两类林地;露石径流输出随露石粗糙度的增加而减小,两者间存在显著的负相关关系。(3)石漠化生态系统的降雨-露石径流转换系数为0.483,显著高于人工林生态系统的0.434和原生林生态系统的0.413,但两类林地的差异性仅在降雨量为小雨时显著。多因素影响下的喀斯特露石径流具有高度异质性,其将对土壤水分、养分异质性与生物多样性的形成产生重要影响。

Karst rock outcrops(ROCs)have important ecological functions;however,few studies have focused on the factors that affect the ROCs runoff output.In this study,ROCs receiving area,roughness and ROCs runoff were measured in three typical karst ecosystems,i.e.rocky desertification,forest plantation,and primary forest ecosystem in Shilin country,Yunnan Province.The results are as follows:(1)There is a highly significant correlation between rainfall received by ROCs and ROCs runoff volume within the rainfall range from 3.92 mm to 72.31 mm.(2)Rainfall,canopy coverage and ROCs roughness affect ROCs runoff output.There is a significant positive correlation between rainfall and ROCs runoff depth.Rainfall received by ROCs and ROCs runoff output in rocky desertification ecosystem are significantly higher than those in other two forest ecosystems.ROCs runoff decreases with the increase of ROCs roughness,and there is a significant negative correlation between them.(3)The conversion coefficient of rainfall to ROCs runoff in rocky desertification ecosystem is 0.483,which is higher than that in plantation and primary forest ecosystems(0.434 and 0.413),but the significant difference in conversion coefficient of rainfall to ROCs runoff in forest plantation ecosystem is only significantly higher than that in primary forest ecosystem when the rainfall is in light degree.Under the influence of multiple factors,karst rock outcrop runoff is highly heterogeneous,which provides strong evidence for the formation of soil moisture heterogeneity,nutrient heterogeneity,and biodiversity in the karst area.