Spatio-temporal variation of vegetation and its topographic differentiation in the Sichuan area of Giant Panda National Park
Sichuan area of Giant Panda National Park is located on the eastern Qinghai-Tibet Plateau and the national key ecological function area.The terrain in the area is complex and varied,with diverse vegetation.It is significant to explore the spatio-temporal characteristics of the vegetation and its relationship with topographic factors in order to scientifically guide the management and ecological construction of giant panda habitat.In this study,we used the Theil-Sen Median trend analysis and the Mann-Kendall test,based on MODIS enhanced vegetation index(EVI)data to investigate the spatial and temporal variation characteristics of vegetation in the Sichuan area of Giant Panda National Park from 2000 to 2020.Additionally,the relationship between EVI and topographic factors such as elevation,slope and aspect were explored by using a topographic difference correction method.The results were as follows:(1)From 2000 to 2020,the averaged EVI appeared to have an overall trend of fluctuation and increase with an average annual variation rate of 0.0019/a,and showed a distribution pattern of high in the east and north but low in the west and south.(2)Vegetation showed an overall improving trend.The vegetation improvement area accounted for 73.99％,which was much larger than the proportion of 12.72％in the vegetation degradation area.Among them,the broadleaf forest improvement area had the largest area proportion of 83.35％,and the meadow degradation area had the largest area proportion of 17.83％.(3)The EVI was significantly negatively correlated with elevation and slope(P＜0.01),and the negative correlation with aspect was not significant.Among them,the meadow was significantly negatively correlated with elevation(P＜0.01)and slope(P＜0.05),and significantly positively correlated with aspect(P＜0.05).The coniferous forest was significantly negatively correlated with elevation and slope(P＜0.01).However,the broadleaf forest and scrub were only significantly negatively correlated with elevation(P＜0.01).(4)The vegetation significant improvement type was the mainly dominant distribution in the area with the elevation below 2500m,slope of 15°—25°,and slope aspect of the north,northeast and northwest slopes.The vegetation significant degradation type was the mainly dominant distribution in the area with the elevation of 3000-3500 m,slope below 15°,and slope aspect of the southeast slope.Therefore,the study reveals the topographic differentiation characteristics of vegetation variation in the Sichuan area of Giant Panda National Park,and provides a scientific basis for the vegetation protection of giant panda habitats under complex terrain.
enhanced vegetation index(EVI)the spatial and temporal variationtopographic factorSichuan area of Giant Panda National Park
万方数据
维普
