旅游干扰下的天山北坡水蚀经济损失评估——以西白杨沟流域山地景区为例

为探讨旅游干扰下山地景区水蚀强度和经济损失变化规律，以水蚀典型区——西白杨沟流域山地景区为案例地，基于样地调查数据，采用中国土壤流失方程（Chinese soil loss equation，CSLE）与水蚀经济损失评估模型，定量估算不同旅游干扰强度下水蚀经济损失，分析西白杨沟景区水蚀经济损失变化规律及其与土壤理化性质、植被覆盖度的关系。结果表明：不同旅游干扰强度下土壤理化性质、植被覆盖度差异显著。与对照组相比，重度干扰区土壤含水量、饱和含水量及土壤孔隙度的降幅分别为51.67%、32.23%、13.30%；土壤碱解氮、有效磷及有机质含量均随干扰强度增加呈下降趋势，而速效钾含量却趋于增加；与对照组相比，轻度、中度、重度干扰区植被覆盖度分别下降14.18%、43.32%、92.35%。随旅游干扰强度的增加，土壤可蚀性K值与生物措施B值明显增加，土壤侵蚀量呈显著增长趋势（P<0.05），与轻度干扰区相比，中度、重度干扰区土壤侵蚀模数增幅分别为79.31%、204.79%。场内经济损失、场外经济损失及水蚀经济总损失随干扰强度的增加呈上升趋势，其中场内经济损失远大于场外经济损失，土壤养分损失及植被多样性损失作为水蚀经济总损失的主要部分，二者在轻度、中度、重度干扰区分别占水蚀经济总损失的93.56%、92.68%、94.94%，且干扰强度为中度、重度时，植被多样性损失高于土壤养分损失，分别达1.17×10⁴元·hm^-2·a^-1和2.49×10⁴元·hm^-2·a^-1。植被覆盖度对水蚀经济损失响应最为敏感，植被覆盖度每减少1%，水蚀经济损失增加4.98×10⁴元。研究表明，旅游干扰强度是影响山地景区水蚀强度和经济损失的关键因素，为此应结合土壤侵蚀参数分析，加强山地景区土体裸露化管理，种植耐践踏植被，核算旅游容量，控制旅游干扰强度。

Evaluation of water erosion loss on the northern slope of Tianshan Mountains under tourism disturbance: Taking west Baiyanggou watershed mountain scenic spot as an example

In order to explore the effect of tourism disturbance on the mountain scenic spot in west Baiyanggou watershed, we quantitatively estimated the economic loss of water erosion under different disturbance intensities, and then analyzed the change law of water erosion economic loss. The relationship of tourism disturbance with soil physical and chemical properties and vegetation coverage was also evaluated, based on data collected in the national soil erosion survey and the Chinese Soil Loss Equation(CSLE) and water erosion economic loss evaluation model. The results showed that under different tourism disturbance intensities, the soil physical and chemical properties and vegetation coverage were significantly different. Compared with the no disturbance sites, the decrease of soil water content, saturated water content, and soil porosity in severe sites were 51.67%, 32.23%, and 13.30%, respectively. The contents of soil available N, P, and organic matter decreased with increasing disturbance intensity, but the content of soil available K tended to increase. The vegetation coverage of the light, moderate, and severe disturbance sites decreased by 14.18%, 43.32%, and 92.35%, respectively, compared with the control group. With the increase of tourism disturbance intensity, the values of soil erodibility K and biological measure B increased significantly, and soil erosion also significantly increased(P<0.05). Compared with light disturbance, the increase of soil erosion modulus in moderate and severe disturbance sites were 79.31% and 204.79%, respectively. On-site and off-site economic losses as well as total water erosion economic losses showed an increasing trend with disturbance intensity. Among them, on-site economic loss was much greater than off-site economic loss, and soil nutrient loss and vegetation diversity loss were the main contributors to the total economic loss of water erosion, which accounted for 93.56%, 92.68%, and 94.94% of the total economic loss of water erosion in the mild, moderate, and severe disturbance sites, respectively. When the disturbance intensity increased, the loss of vegetation diversity was higher than the loss of soil nutrients, and it would have a primary water erosion economy loss of 1.17×10⁴ yuan·hm^-2·a^-1 and 2.49×10⁴ yuan·hm^-2·a^-1 in moderate and severe sites, respectively. Vegetation coverage was the most sensitive to water erosion economic loss. Every 1% reduction in vegetation coverage lead to 4.98×10⁴ yuan increasing in water erosion economic loss. The study also indicated that tourism disturbance intensity is a key factor affecting the water erosion intensity and economic loss in mountain scenic spots. Therefore, to control the intensity of tourism disturbance, it should be combined with the analysis of soil erosion parameters, strengthening the management of soil exposure, the use of plant trample resistant vegetation, and assessment of tourism carrying capacity.