Modeling the regional grazing impact on vegetation carbon sequestration ability in Temperate Eurasian Steppe

Anthropogenic activities profoundly influence carbon sequestration in the Eurasian Steppe. In particular, grazing has been identified as having a major effect on carbon sequestration. However, the extent to which grazing affects regional patterns or carbon sequestration is unknown. In this study, we evaluated the impact of regional grazing on grassland carbon seques- tration using the Boreal Ecosystem Productivity Simulator （BEPS） and the Shiyomi grazing model. Model performances were validated against the results from field measurements and eddy covariance （EC） sites. Model outputs showed that in 2008, the regional net primary productivity （NPP） was 79.5 g C m-2, and the net ecosystem productivity （NEP） was -6.5 g C m-2, characterizing the region as a Weak carbon source. The Mongol Steppe （MS） was identified as a carbon sink, whereas the Kazakh Steppe （KS） was either carbon neutral or a weak carbon source. The spatial patterns of grazing density are divergent between the MS and the KS. in the MS, livestock was mainly distributed in China with relatively good management, while in the KS livestock was mainly concentrated in the southern countries （especially Uzbekistan and Turkmenistan） with harsh environments and poor management. The consumption percentages of NPP in Turkmenistan, Tajikistan and Uzbekistan were 5.3, 3.3 and 1.2%, respectively, whereas the percentages in other countries were lower than 1%. Correspondingly, grazing consumption contributed to the carbon sources of Turkmenistan, Tajikistan and Uzbekistan by 11.6, 6.3 and 4.3%, respectively, while it weakened the carbon sink in Inner Mongolia, China and Mongolia by 1.6 and 0.5%. This regional pattern should be affected by different sub-regional characteristics, e.g., the continuous degradation of grassland in the southern part of the KS and the restoration of grassland in Inner Mongolia, China.

Spatial pattern of grassland aboveground biomass and its environmental controls in the Eurasian steppe

Vegetation biomass is an important component of terrestrial ecosystem carbon stocks. Grasslands are one of the most widespread biomes worldwideplaying an important role in global carbon cycling. Thereforestudying spatial patterns of biomass and their correlations to environment in grasslands is fundamental to quantifying terrestrial carbon budgets. The Eurasian steppean important part of global grasslandsis the largest and relatively well preserved grassland in the world. In this studywe analyzed the spatial pattern of aboveground biomass（AGB）and correlations of AGB to its environment in the Eurasian steppe by meta-analysis. AGB data used in this study were derived from the harvesting method and were obtained from three data sources（literatureglobal NPP database at the Oak Ridge National Laboratory Distributed Active Archive Center（ORNL）some data provided by other researchers）. Our results demonstrated that：（1） as for the Eurasian steppe overallthe spatial variation in AGB exhibited significant horizontal and vertical zonality. In detailAGB showed an inverted parabola curve with the latitude and with the elevationwhile a parabola curve with the longitude. In additionthe spatial pattern of AGB had marked horizontal zonality in the Black Sea-Kazakhstan steppe subregion and the Mongolian Plateau steppe subregionwhile horizontal and vertical zonality in the Tibetan Plateau alpine steppe subregion.（2） Of the examined environmental variablesthe spatial variation of AGB was related to mean annual precipitation（MAP）mean annual temperature（MAT）mean annual solar radiation（MAR）soil Gravel contentsoil p H and soil organic content（SOC） at the depth of 0–30 cm. NeverthelessMAP dominated spatial patterns of AGB in the Eurasian steppe and its three subregions.（3） A Gaussian function was found between AGB and MAP in the Eurasian steppe overallwhich was primarily determined by unique patterns of grasslands and environment in the Tibetan Plateau. AGB was significantly positively related to MAP in the Black Sea-Kazakhstan steppe subregion（elevation 〈 3000 m）the Mongolian Plateau steppe subregion（elevation 〈 3000 m） and the surface（elevation ≥ 4800 m） of the Tibetan Plateau. Neverthelessthe spatial variation in AGB exhibited a Gaussian function curve with the increasing MAP in the east and southeast margins（elevation 〈 4800 m） of the Tibetan Plateau. This study provided more knowledge of spatial patterns of AGB and their environmental controls in grasslands than previous studies only conducted in local regions like the Inner Mongolian temperate grasslandthe Tibetan Plateau alpine grasslandetc.

Reconsideration of the origins of the pastoral nomadic economy in the Eurasian Steppe

Archaeological discoveries indicate that a variety of economic models have operated in the inland areas of Asia.One of these models,pastoral nomadism,differs from agriculture,agro-pastoral,and settled pastoralism in terms of cattle-breeding,cultivation and manufacture.Pastoral nomadism is a livestock-breeding management mode of production,in which the stock is fed by uninterrupted moving in a large geographical area.The Eurasian Steppe,which includes the cold forest-steppe area in the north and the semi-arid desert-steppe in the south,is the major region in which the ancient nomadic population flourished.Because of the absence of both intrinsic motivation and external pressure for the transition to pastoral nomadism,early animal husbandry economy in the forest-steppe area could not have developed into the initial pastoral nomadic economy;instead,the pastoral nomadic economy emerged from the agro-pastoral economy in the semi-arid desert-steppe.These agro-pastoral people were forced to minimize the scale of agriculture and sedentary pastoralism and to turn to a nomadic lifestyle,with the internal cause being a shortage of feed resources caused by expansion of the human population and livestock,with the added external pressure of climatic and environmental deterioration.From archaeological findings,the eastern Tianshan area in Xinjiang,China,was a major region for the emergence of the early pastoral nomadic economy.The main evidence for this conclusion is a series of pastoral nomadic settlement sites in the northern and southern piedmonts of the Tianshan Mountains,which display settlement conditions,resources and environments entirely different from those of agricultural and agro-pastoral settlements elsewhere.

大连岗上类型积石冢与欧亚草原石板墓文化关系研究——兼谈萨满教在文化传播中的作用

通过研究夏家店上层文化与大连岗上类型积石冢和欧亚草原石板墓文化的关系,证明了岗上类型积石冢产生的变化应与石板墓文化向东南的输出有关。在相距如此之远的两种文化之间产生的交流与影响,萨满教文化在其中发挥了巨大的作用。