Jiuquan City is a typical ecologically fragile area in the arid areas of Northwest China, and unreasonable human activities directly affect the regional ecological security. Scientifically, it is necessary to construct an ecological landscape pattern on the basis of ecological security evaluation. This paper selected evaluation factors based on the perspective of “environmental base and human interference”, used spatial principal component analysis (SPCA) to comprehensively evaluate the regional landscape ecological security, and used the minimum cumulative resistance (MCR) model to construct the regional ecological security pattern. The results show that the overall ecological security level of the study area is low, and the area with a moderate safety level and below is 122,100 km2, accounting for 72.57% of the total area of the study area. The total area of the identified ecological source area is 6683 km2, the spatial distribution is extremely uneven, and it is extremely concentrated in the southern region; 32 ecological corridors with a total length of 3817.8 km are identified, of which corridor NO. 1–4 run through the Qilian Mountains, 11 oasis areas, and 14 nature reserves. The length of ecological corridors is 1376.1 km, accounting for 36.04% of the total. Forty-two ecological nodes are identified, and the central corridor area is more distributed; four ecological restoration zones are divided, including an ecological conservation zone, ecological improvement zone, ecological control zone, and ecological restoration zone, with areas of 34,380.3 km2, 61,884.4 km2, 21,134.4 km2, and 50,648.3 km2, respectively. Through the delineation of the urban ecological network pattern composed of source areas, corridors, and nodes, as well as the delineation of ecological restoration zones, the ecological security level of the study area will be effectively improved. Furthermore, a new method of ecological restoration zoning will be used, hoping to provide a useful reference for improving the quality of the ecological environment in arid areas and optimizing the spatial pattern of the land.

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The study explores the characteristics of urban spatial expansion and dynamic mechanism by using expansion speed index, expansion intensity index, compact index, fractal dimension, and extended flexibility index. We built the index system of influencing factors of urban spatial expansion by using the grey incidence model. The results showed that urban spatial expansion rate in the Hexi Corridor has been on the upward trend since 1987. Expansion intensity showed an obvious upward trend, however, the upward trend varied in different urban areas. In addition, the urban structure was loose relatively, but the urban compactness was more obvious. The urban spatial form tended to be simple, and the urban land use tended to become more intensive. Urban spatial expansion experienced several stages: padding internally, external expansion and padding internally. The main driving factors of urban spatial expansion are not the urban water resources and the oasis scale, but one or several factors such as economy, traffic, population, resource and national policy.

The Thornthwaite moisture index, an index of the supply of water (precipitation) in an area relative to the climatic demand for water (potential evapotranspiration), was used to examine the spatial and temporal variation of drought and to verify the influence of environmental factors on the drought in the Hengduan Mountains, China. Results indicate that the Thornthwaite moisture index in the Hengduan Mountains had been increasing since 1960 with a rate of 0.1938/yr. Annual Thornthwaite moisture index in Hengduan Mountains was between -97.47 and 67.43 and the spatial heterogeneity was obvious in different seasons. Thornthwaite moisture index was high in the north and low in the south, and the monsoon rainfall had a significant impact on its spatial distribution. The tendency rate of Thornthwaite moisture index variation varied in different seasons, and the increasing trends in spring were greater than that in summer and autumn. However, the Thornthwaite moisture index decreased in winter. Thornthwaite moisture index increased greatly in the north and there was a small growth in the south of Hengduan Mountains. The increase of precipitation and decrease of evaporation lead to the increase of Thornthwaite moisture index. Thornthwaite moisture index has strong correlation with vegetation coverage. It can be seen that the correlation between Normalized Difference Vegetation Index (NDVI) and Thornthwaite moisture index was positive in spring and summer, but negative in autumn and winter. Correlation between Thornthwaite moisture index and relative soil relative moisture content was positive in spring, summer and autumn, but negative in winter. The typical mountainous terrain affect the distribution of temperature, precipitation, wind speed and other meteorological factors in this region, and then affect the spatial distribution of Thornthwaite moisture index. The unique ridge-gorge terrain caused the continuity of water-heat distribution from the north to south, and the water-heat was stronger than that from the east to west part, and thus determined the spatial distribution of Thornthwaite moisture index. The drought in the Hengduan Mountains area is mainly due to the unstable South Asian monsoon rainfall time.