Climate change is projected to increase the aridity of semi-arid ecosystems, including Mongolian grasslands (MG), which provide ecosystem services that support food supply and pastoralist lifestyle. Here, we conducted a grid-scale (0.5° × 0.5°) probabilistic risk assessment of MG under climate change for 40 years (1976–2015) based on probability theory. We evaluated changes of risk (impacts) and vulnerability of MG to drought between the recent two decades R20 = 1996–2015 and the previous two decades P20 = 1976–1995. The risk is quantified as the product of the probability of hazardous drought and ecosystem vulnerability. The probability of hazardous drought is defined from the Standardized Precipitation–Evapotranspiration Index. Vulnerability is defined as the expected differences of key ecosystem variables between years with and without hazardous conditions. The ecosystem variables are productivity (peak aboveground biomass, net primary productivity, and leaf area index) and root-zone plant-available soil moisture, simulated with a process-based vegetation model Organizing Carbon and Hydrology in Dynamic Ecosystems-Grassland Management validated with field observations of biomass and soil moisture. Results reveal that MG experienced more frequent hazardous droughts with rapid warming and slight drying during R20 aggravated by ever-increasing grazing intensity (34% compared to P20), which resulted in a reduction in soil water availability and grassland productivity, particularly in northeastern areas (20%–65%). The risk of drought to productivity increased by 10% between P20 and R20 over extended areas, particularly in northcentral and northeast Mongolia. The increase in the risk to MG was mainly caused by climate change-induced increase in the probability of hazardous drought and, to a lesser extent, by the increasing vulnerability. Recent droughts modify the risk to grasslands, particularly in northcentral and northeast Mongolia, suggesting that these regions need strategic management for both adaptation and ecosystem conservation to cope with climate change impacts.

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Mongolian pastoral nomads traditionally consume meat during the cold season and milk products during the warm season. Among these is airag (fermented mare's milk), and Mongolia is one of the few regions that retains such traditional food. Through the Mongolian meteorological network, this is the first survey on airag, targeting 2,045 herders. We compared airag production between households producing it and households in general. Results revealed intensive production in central Mongolia, but less in surrounding areas, except along the western border. High horse-density in the central steppes and forest steppes provides an eco-climatological explanation, but this density pattern cannot explain inadequate production in eastern areas. Thus, culture and ethnicity may account for airag's regional distribution.

Airag, (Fermented horse milk) is a traditional milk product in Mongolia. Herders separate foals from their dams and tie them at a milking site during the daytime to produce airag. To evaluate the effects of horse management on the movement of dams, we tracked three dams in a herd in camp 1 during summer and camp 2 during autumn of 2013 and analyzed their movements during the milking (daytime) and non-milking (nighttime) periods in an area famous for its high-quality airag. Dams were gathered every 1.7 AE 0.0 h between 07.46 and 15.47 hours at the milking sites and milked 4.6 AE 0.2 times/day during the study period (86 days). Daily cumulative and maximum linear distances from the milking sites were longer (P < 0.01) during the non-milking period than during the milking period. Daily home ranges were 91 and 26 times greater during the non-milking period (P < 0.001) in camps 1 and 2, respectively. The greater range during the non-milking period would reflect the spatial distributions of water, salt and forage. The dams initially used similar areas and gradually shifted their daily home ranges after several days. This shift suggests that the dams grazed farther afield as forage availability declined around the milking site. For better airag production and sustainable pasture use, our results provide insights useful for evaluating the effects of milking management on vegetation and soil in those pastures, for selecting the appropriate milking times and frequency, and for choosing the right timing to shift milking sites.

Photosynthetically active radiation (PAR) is an important input parameter for estimating plant productivity due to its key role in the growth and development of plants. However, a worldwide routine network for systematic PAR measurements is not yet established, and PAR is often calculated as a constant fraction of total solar radiation (SR). Although the ratio of PAR to SR (PAR/SR) has been reported from many places, few studies have been performed for dry regions. The present study was therefore carried out in an arid region of Mongolia to obtain PAR/SR and examine its dependency on sky clearness (the clearness index), water vapor in the atmosphere and aeolian dust. Continuous measurements of PAR and SR were taken every one second using quantum and pyranometer sensors, respectively, and the readings were averaged and recorded at intervals of 30 minutes for a period of 12 months. The lowest monthly mean daily PAR/SR occurred in April (0.420), while the highest ratio was observed in July (0.459). Mean daily PAR/SR during plant growing season (May−August) was estimated to be 0.442, which could be useful for modeling plant productivity in the study area. The annual mean daily PAR/SR (0.435) was lower than the values reported in many previous studies. This difference could be explained with the regional variation in climate: i.e. drier climatic condition in the study area. PAR/SR was negatively correlated with the clearness index (r=-0.36, P<0.001), but positively with atmospheric water vapor pressure (r=0.47, P<0.001). The average PAR/SR was significantly lower (P=0.02) on the dusty days compared to the non-dust days. Water vapor in the atmosphere was shown to be the strongest factor in the variation of PAR/SR. This is the first study examining PAR/SR under a semi-arid condition in Mongolia.