Landscape pattern changes and their driving factors in the farming-pasture ecotone, Eastern Qilian Mountains, from 1988 to 2018

To explore landscape spatial pattern changes and their driving factors over a 30 year period (1988 to 2018), we used visual interpretation and landscape pattern indexes to analyze remote sensing images of the upper Jinqiang River on a farming-pasture ecotone in the Tianzhu Tibetan Autonomous County. The results showed that: 1) Grassland was the largest landscape type with an area increase of 37.2 km² over the 30 year period. In particular, the moderate-coverage grassland increased by 102.5 km² during the last 10 years, and the shrubland decreased by 37.5 km², being mainly converted to grassland. 2) From 1988 to 2018, the population increased by 13.9%, and the construction land area increased by 142.4%, whereas the cultivated land area decreased by 4.4 km², and the degree of human disturbance increased by 20.2%. 3) The landscape shape index increased by 9.09, whereas the contagion and aggregation indexes decreased by 0.45% and 2.76%, respectively. The landscape tended to be complicated and fragmented. 4) Human activity appears to be the main factor driving the landscape pattern changes, followed by climate factors. National policy plays an important guiding role in environmental improvement. To realize ecosystem protection and sustainable development, reduction of excessive human activity impact on the farming-pasture ecotone in Eastern Qilian Mountains is essential.