Analysis on Ecological Environment Change of Kalajun-Kurdening World Natural Heritage Site from 2006 to 2019

Scientific evaluation and dynamic monitoring of regional ecological environment have important reference value for the establishment and implementation of regional ecological environment protection and restoration measures. Spatial principle component analysis was used to assess the present situation and the temporal and spatial variation characteristics of ecological environment of Kalajun-Kurdening natural heritage site by calculating the remote sensing ecological index (RSEI) and analyzing the landscape pattern. Three results are presented: (1) During 2006-2019, the mean values of the greenness indicator showed an increasing trend, with an increase of 10.58%, which proves that the vegetation coverage in Kalajun-Kurdening shows an increasing trend year by year. The other three indicators of dryness, moisture, and heat decreased by 134.51%, 14.66%, and 3.45% respectively. The change of greenness and dryness has a stronger positive effect on the ecological environment quality, while the negative effect of heat on the ecological environment quality is reduced. (2) During the 14 years, the regional RSEI of 1104.23 km(2) remained unchanged, accounting for 54.32% of the total area. The area with a descending RSEI is 547.23 km(2), accounting for 26.92% of the total area, 84.52% of which had a drop of one level. The area with the rising RSEI is 381.31 km(2), accounting for 18.75% of the total area, 90.56% of which has a rising by one level. (3) Landscape indexes of the different grade of RSEI in Kalajun-Kurdening showed that the landscape fragmentation was small, the structural complexity was reduced, and the landscape patches were regularized, artificial, and centralized; different types of RSEI had obvious agglomeration; and the cohesion between patches was relatively good. Overall, the ecological environment quality of the Kalajun-Kurdening world natural heritage site showed an upward trend from 2006 to 2019 without large-scale deterioration of, maintaining in good condition.