九寨沟景区“8·8”地震前后及钙华生境保育修复后植被和水系的动态变化

Dynamic evolution of vegetation and drainages in the Jiuzhaigou valley scenic area before and after the"8 August 2017"earthquake under conditions of travertine habitat conservation and restoration

利用Landsat-8、高分1号、2号等卫星影像,评估九寨沟核心钙华景点及整个景区在“8∙8”地震前、后和钙华生境保育修复后植被覆盖度、土壤湿度、森林面积和水系面积的动态变化。结果显示:人工为辅、自然为主的钙华保育修复后钙华核心景点和整个景区的高植被、中低植被、低植被覆盖面积均有了显著增加,裸地生态类型仍存在,但呈逐年减少趋势,中植被覆盖类型较震后和震前减少;保育后第二年,湿润和很湿润面积、总森林面积和水系面积比震前和震后都有大幅增加,高植被覆盖度面积、森林面积和水系面积间存在正相关关系,可能是由于人工干预下原生境快速恢复,提高了植被覆盖面积,植被的蒸散和截流作用进一步影响了流域的水文过程,促进了水系面积的恢复。

The restoration of the original habitat after an earthquake is very important for rapid reconstruction of territorial vegetation and the restoration of the drainage area.In this study,the dynamic changes of vegetation coverage,soil moisture,forest area and river system area of the Jiuzhaigou valley core travertine scenic spot and the whole scenic spot before and after the 2017 earthquake and after the travertine habitat conservation and restoration were evaluated by using Landsat-8,and Gaofen 1#,2#satellite images.The results show that the coverage area of high,medium and low vegetations at the travertine core scenic spot and the whole scenic spot has increased significantly after the travertine conservation and restoration with artificial as auxiliary and natural as the main.The ecological types of bare land still exist,but show a decreasing trend year by year.In addition,the types of medium vegetation cover also decreased compared with those after and before the earthquake.In the second year after conservation,wet and very humid areas,total forest area and river system area increased significantly compared with before and after the earthquake.Overall,there is a positive correlation among high vegetation coverage area,forest area and river area.This may be due to the rapid restoration of original habitat under human intervention,which increased vegetation coverage area,and enhanced the roles of vegetation evapotranspiration and interception,and further affected the hydrological process of the watershed and promoted the restoration of the drainage area.