[Spatial and temporal variation in normalized difference vegetation index of vegetation in Liaoning Province from the perspective of ecogeographic zoning]. / 生态地理分区视角下的辽宁省植被归一化植被指数的时空变化.

Normalized difference vegetation index (NDVI) is an important indicator reflecting vegetation cover and growth status. It is of significance for regional ecological conservation and natural resource management to investigate its spatial and temporal variation trends and response to ecological factors. We divided Liaoning Province into three ecological geographical regions, including northwest agro-pastoral zone, central agricultural zone, and eastern agroforestry zone. Based on remote sensing, vegetation, climate, topography and human activities, we used trend analysis and geographic probe model to examine the spatial and temporal trends of NDVI in Liaoning Province, and analyzed the intensity and interaction mechanism of each driver on the spatial distribution pattern of NDVI. The results showed that the annual average NDVI in Liaoning Province from 2001 to 2020 was 0-0.92, showing a distribution pattern of high in the east and low in the west, high in the inland and low in the coastal land. The overall trend of vegetation cover was increasing, and the NDVI increasing areas were mainly concentrated in the northwest agro-pastoral zone and the eastern agroforestry zone, the NDVI reduction areas were mainly concentrated at the border between the central agricultural zone and the eastern agroforestry zone, as well as in the coastal area of the eastern agroforestry zone. The annual average NDVI change varied among the three ecological-geographic zones. The NDVI of the northwest agro-pastoral zone from 2001 to 2020 were generally low, but showed a fluctuating trend of slow increase. The NDVI of the eastern agroforestry zone was high overall, and the interannual variation of NDVI was generally stable. The distribution of high and low NDVI in the central agricultural zone was staggered, and the interannual variation of NDVI showed a decreasing trend. Natural factors were the key drivers of NDVI changes in the three ecogeographic zones, with cumulative temperature and precipitation having the greatest influence. The interactions between the factors were all mutually and nonlinearly enhanced.

[A services value of different landscape types in Longitudinal Range-Gorge Region].

Based on the RS image of Longitudinal Range-Gorge Region (LRGR) in 2001, the study area was classified into seven first-class landscape types (forestland, grassland, farmland, wetland, water body, urban land, and glacier), and 26 second-class landscape types in consideration of climate belt, vegetation, and topography. By using GIS technology, the services value of different landscape types of LRGR were studied in regards to the study results on services value of Chinese terrestrial ecosystems. The results indicated that the total services value of LRGR was 5 302.35 x 10(8) yuan x a(-1), accounting for 9.47% of the whole country. The service value of soil conservation was the highest, which occupied 18.05% of the total services value, while the service values of gas adjustability and biodiversity protection ranked the second and third. Due to its distribution extent and services intensity per unit area, the forest landscape, which covered 66.11% of the total area, contributed most (85.34%) to the total service value of LRGR, followed by grassland and farmland landscapes.