Desertification is among the most severe global environmental and the socio-economic problems in the world. This paper is a first attempt to link scientific research to national policymaking on desertification in China. We aim to trace scientific research findings in the national policies and strategies of desertification prevention in China. One example is the large-scale plantation programme in the dust source region threatening Beijing and Tianjin since 1998. It has been suggested that the recent increased forest cover due to plantations in North China has helped reduce dust storm emissions and contributed to mitigating dust storm weather in Beijing and Tianjin. Reforestation/afforestation policy remains in the Chinese national environmental strategies for the new national forestation programme (2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018)(2019)(2020). Overgrazing during recent decades has been blamed for land degradation and desertification in Northwest China by many scholars. Small field experiments prove that vegetation in desertified/degraded land could recover if isolated from human activities. Since 1998, natural recovery has become one powerful national force to prevent land desertification and recover natural vegetation. One example is selected at Cele County, Xinjiang Uygur Autonomous Region to showcase how vegetation could thrive at large scale in natural arid and semi-arid climate if isolated from human intervention. The plantation project has pushed the stakeholders to better understand their negative impact on the environment, especially the overgrazing behaviour. After that, the household income and living level have also been significantly enhanced; however, it is not clear whether the project induced labour migration.
Drought has become a major threat to local sustainable development in dryland Asia, one of the largest grassland ecosystems in the world. However, empirical-and science-based evidence regarding the extent of drought changes and the future trends of these changes in dryland Asia is variable and incomplete. Here, we first investigate the historical variations in drought conditions in dryland Asia, as measured by the drought intensity and arid area, using three widely used drought indices (the Palmer Drought Severity Index, the Standardized Precipitation Index, and the Standardized Precipitation Evapotranspiration Index). Then, we use Bayesian model averaging to reproduce the future drought conditions under two representative concentration pathways (RCP2.6 and RCP4.5) from the Coupled Model Intercomparison Project Phase 5 Earth system models. The Palmer Drought Severity Index, Standardized Precipitation Index, and Standardized Precipitation Evapotranspiration Index illustrate that dryland Asia has experienced an overall drying trend and an expansion of arid areas over the past 100 years (1901-2016). Both temperature and precipitation are projected to increase under both the 1.5 and 2.0°C warming scenarios compared with the values from the reference period (1986-2005). The projected drought conditions in the 1.5 and 2.0°C warming scenarios will worsen, especially across Kazakhstan and Northwest China. We found that the drought conditions under the 2.0°C warming conditions will not be as severe as those under the 1.5°C warming conditions due to the mitigating effect of the projected precipitation increase under RCP4.5. These results call for short-term and long-term mitigation and adaptation measurements for drought events in dryland Asia. Plain Language Summary To avoid the negative impacts of climate warming, the Paris Agreement aims to pursue efforts to maintain the global warming increase at well below 1.5 and even 2.0°C until the end of the century. Questions have been raised regarding the climate extremes in dryland Asia. Will drought issues become more severe under the context of global warming? Are the existing drought indices able to quantify and characterize the drought intensity and arid area in this region? Answers to these questions are crucial for the livelihood of millions of individuals, as these people rely on grassland biomass to feed both animals and farmers; however, the answers remain unclear. Here, we found that the projected drought severity and arid area will persistently increase under both the 1.5 and 2.0°C global warming scenarios. We also found that the drought conditions under the 2.0°C warming scenario will be mitigated relative to those under the 1.5°C warming scenario due to the beneficial effect of adequate precipitation under representative concentration pathway 4.5. Kazakhstan and Northwest China might be severely affected by drought. Therefore, understanding future changes in drought conditions in dryland Asia is critical for developing adaptation measures to cope with the challenge...
Cultivated peanut (Arachis hypogaea L.) were classified into six botanical varieties according to the morphological characteristics. However, their genetic evolutionary relationships at the genome-wide level were still unclear. A total of 320 peanut accessions, including four of the six botanical varieties, and 37,128 high-quality single nucleotide polymorphisms (SNPs) detected by tunable genotyping-by-sequencing (tGBS) were used to reveal the evolutionary relationships among different botanical varieties and verify the phenotypic classification. A phylogenetic tree indicated that the tested accessions were grouped into three clusters. Almost all of the peanut accessions in cluster C1 belong to var. fastigiata, and clusters C2 and C3 mainly consisted of accessions from var. vulgaris and subsp. hypogaea, respectively. The results of a principal component analysis were consistent with relationships revealed in the phylogenetic tree. Population structure analysis showed that var. fastigiata and var. vulgaris were not separated when K = 2 (subgroup number), whereas they were clearly divided when K = 3. However, var. hypogaea and var. hirsuta could not be distinguished from each other all the way. The nucleotide diversity (π) value implied that var. vulgaris exhibited the highest genetic diversity (0.048), followed by var. fastigiata (0.035) and subsp. hypogaea (0.012), which is consistent with the result of phylogenetic tree. Moreover, the fixation index (FST) value confirmed that var. fastigiata and var. vulgaris were closely related to each other (FST = 0.284), while both of them were clearly distinct from var. hypogaea (FST > 0.4). The present study confirmed the traditional botanical classifications of cultivated peanut at the genome-wide level. Furthermore, the reliable SNPs identified in this study may be a valuable resource for peanut breeders.
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