Determining vegetation variation and its influential factors in a desert steppe under the impacts of climate change and human activities is crucial and meaningful for improving the understanding of desertification and taking targeted measures in ecological restoration. As compared to a large spatial scale such as a region or a whole catchment, which are more common in published studies, a micro perspective at the pixel level is provided in this study to investigate the vegetation fractional coverage dynamics and build the correlations between vegetation fractional coverage and its multiple influential factors, including precipitation, temperature, soil water, groundwater and human activities in a desert steppe region in the Inner Mongolia Autonomous Region, China. The average vegetation fractional coverage in August for the years 2000–2011 is 0.38 in the study area. The interaction of rain (R = 0.80) and heat (R = −0.76) significantly determines the growth and distribution of the vegetation in the study area. Besides, the effects of some other factors on vegetation fractional coverage should not be neglected, including groundwater (R = 0.04), available water content of soil (R = 0.23) and livestock density (R = 0.28). From the perspective of centre dynamics for the years 2000–2011, the annual precipitation centre has better synchronism with the vegetation centre, while the movement of the temperature centre is more stable.

Neither single nor discontinuous hydrological observation data can truly reflect periodic changes in soil moisture under natural conditions or interrelationships between various water sources. Therefore, in this study, precipitation pulse characteristics and variations in the soil water content (SWC) and actual evapotranspiration (ET_a) in relation to pulses are explored through a field multi-water continuous observation system set in desert steppe in Inner Mongolia, China. A comparison between precipitation events in the growing seasons of 2016 and 2017 shows that precipitation events that are greater than 10 mm are the main cause of dramatic interannual precipitation variations in this region. A single small precipitation event has a limited impact on SWC and provides no obvious increase in the SWC within the top 10 cm soil layer. The precipitation interval ratio (P/I) is suitable for comparing water stresses of different drying-wetting cycles, and correlations between soil layers are found to be closer in humid years than in dry years. In this study, three modes of interpulse ET_a in the desert steppe are discussed: a stable ET_a mode under a water-sufficient condition, an attenuation ET_a mode, and a stable ET_a mode under extreme drought conditions.

Based on the national precipitation dataset in the Huang-Huai-Hai River Basin of China for the 1961–2011 period, the China-Z growing season index was calculated to analyze the characteristics of the evolution of meteorological droughts. Data from statistical droughts (the droughts which are defined and classified by the actual statistic data) were compared with those of meteorological droughts during the 2000–2011 period. Nine indexes were selected to evaluate the drought coping ability of water conservancy projects based on the fuzzy comprehensive assessment model. The results showed that the China-Z growing season index was a downward trend with a rate of −0.063 per decade from 1961 to 2011, which indicates an increasing trend in drought intensity. Droughts were more frequent than average during the 1961–1979 period and returned to normal frequency during the 1980–2011 period. Both the ratio of drought affected area (RDAA) and the ratio of drought suffering area (RDSA) of statistical droughts decreased more quickly than those of meteorological droughts (2000–2011). The indexes of water conservancy projects were lower than the average all-China indexes. Half of the 59 three-level water resources districts exhibited a relatively poor drought coping ability, which means that enhancing the drought coping ability of the water conservancy project was quite important.