天山野果林区滑坡景观时空演变及生态风险预测

以天山大小莫合流域野果林区为例,探究其景观格局的时空演变特征及揭示滑坡对野果林区造成的生态风险具有重要意义。以Corona和Spot-5等高分辨率遥感影像为数据源,通过RS技术解译1964、1980、2000、2017年空间数据,利用Fragstats 4.0软件计算景观特征指数,并探讨了滑坡景观格局时空变化特征与演化的驱动因素,从而进行景观生态风险预测。结果表明:(1)1964—2017年野果林面积持续减少了3942.15 hm2,主要向草地、耕地转移面积为主,滑坡区面积增加了203.48 hm2,其主要转入景观类型为野果林、草地。(2)野果林区各景观破碎程度加剧,景观边界形状总体上趋于复杂。不同景观斑块面积呈现不均匀状态,景观的空间异质性增强。(3)滑坡景观类型变化受自然因素和人文因素共同影响作用。人口增加和人为干扰度是主要的人文驱动因子,气温、坡度、坡向和降水是主要的自然驱动因子。(4)2017年景观生态风险以高风险等级和较高生态风险等级为主,此阶段,野果林区生态系统稳定性低,其生态环境脆弱;2034年滑坡景观生态风险有减弱趋势,野果林区生态系统趋于稳定,但滑坡等自然灾害仍不容忽视。

Spatio-temporal Evolution and Ecological Risk Prediction of Landslide Landscape in the Tianshan Wild Fruit Forest Area

Take the wild fruit forest area of the Mohe River Basin in Tianshan area as an example,it is of great significance to explore the spatial-temporal evolution of landscape pattern in wild fruit forest and to reveal the ecological risks caused by landslides.The Corona and Spot-5 high-resolution images were used as data sources,the spatial data in 1964,1980,2000 and 2017 were interpreted by RS method,the Fragstats 4.0 software was used to calculate the landscape feature index and the spatial and temporal changes of landscape pattern and the driving factors were discussed,thus which predicted the landscape ecological risk.The results are as follows:(1)From 1964 to 2017,the wild fruit forest area continued to decrease by 3942.15 hm2,which mainly transferred to grasslands and cultivated lands,and the landslide area increased by 203.48 hm2,the predominant landscape types transferred to wild fruit forests and grasslands.(2)The landscape fragmentation in wild fruit forest area was aggravated,and the landscape boundary shape tended to be complex on the whole.The patch area of different landscapes presented uneven,and the spatial heterogeneity of the landscape was enhanced.(3)The landscape type change of landslide was affected by both natural and human factors.Population increase and human disturbance degree was the main human driving factors,while temperature,slope,slope direction and precipitation were the main natural driving factors.(4)The landscape ecological risks in 2017 were mainly high risk and higher ecological risk.At this stage,the ecosystem stability of wild fruit forest area was low.Seriously damaged by man-made disturbances and natural disasters,its ecological environment was fragile;The ecological risk of the landslide landscape will weaken in 2034,and the ecosystem of the wild fruit forest area will stabilize,but natural disasters such as landslide cannot be ignored.