Recent Jishishan earthquake ripple hazard provides a new explanation for the destruction of the prehistoric Lajia Settlement 4000a B.P.

The Jishishan Ms 6.2 earthquake occurred at 23:59 on December 18, 2023 in Gansu Province, China. We conducted a field survey to assess the hazards and damages caused by the earthquake and its associated geo-activities. Subsequently, we organized a seminar to discuss the possible causes of the destruction of a prehistoric site-Lajia Settlement-dated back to four thousand years B.P. and located only several kilometers away from the epicenter of the Jishishan earthquake. The Jishishan earthquake was unique for its hazard and disaster process, which featured ground shaking and a series of complex geological and geomorphological activities: sediment and soil spray piles, liquefaction, collapse, landslide, and mudflow along water channels. We define this phenomenon as the Jishishan earthquake ripple hazard (JERH). The most recent evidence from the JERH suggests that a prehistoric earthquake similar to the JERH, instead of riverine floods or earthquake-induced landslide dam outburst flood, as previously hypothesized, destroyed the Lajia Settlement.

Spatial-temporal evolution of production-living-ecological space and layout optimization strategy in eco-sensitive areas: a case study of typical area on the Qinghai-Tibetan Plateau, China.

To achieve sustainable development goals and to solve environmental problems, land resources in eco-sensitive areas should be used and optimized. Qinghai, which is an important eco-sensitive area in China, represents a typical ecological vulnerable region on the Qinghai-Tibetan Plateau. Using land use/cover data for 2000, 2010 and 2020, this study applied a series of quantitative methods to analyze the spatial pattern and structure of the production-living-ecological space (PLES) in Qinghai. The results indicated that the spatial pattern of the PLES in Qinghai was stable over time, but the spatial distribution was very different. The structure of the PLES in Qinghai was stable, and the proportion of each space from high to low was ecological (81.01%), production (18.13%) and living (0.86%). We found that the proportion of ecological space in both the Qilian Mountains and the Three River Headwaters Region was lower than the rest of the study area, except for the Yellow River-Huangshui River Valley. Our study objectively and credibly presented the characteristics of the PLES in an important eco-sensitive area in China. This study further formulated targeted policy suggestions to provide a basis for regional sustainable development, ecological environment protection, and land and space optimization in Qinghai.

Substantial transition to clean household energy mix in rural China.

The household energy mix has significant impacts on human health and climate, as it contributes greatly to many health- and climate-relevant air pollutants. Compared to the well-established urban energy statistical system, the rural household energy statistical system is incomplete and is often associated with high biases. Via a nationwide investigation, this study revealed high contributions to energy supply from coal and biomass fuels in the rural household energy sector, while electricity comprised ∼20%. Stacking (the use of multiple sources of energy) is significant, and the average number of energy types was 2.8 per household. Compared to 2012, the consumption of biomass and coals in 2017 decreased by 45% and 12%, respectively, while the gas consumption amount increased by 204%. Increased gas and decreased coal consumptions were mainly in cooking, while decreased biomass was in both cooking (41%) and heating (59%). The time-sharing fraction of electricity and gases (E&G) for daily cooking grew, reaching 69% in 2017, but for space heating, traditional solid fuels were still dominant, with the national average shared fraction of E&G being only 20%. The non-uniform spatial distribution and the non-linear increase in the fraction of E&G indicated challenges to achieving universal access to modern cooking energy by 2030, particularly in less-developed rural and mountainous areas. In some non-typical heating zones, the increased share of E&G for heating was significant and largely driven by income growth, but in typical heating zones, the time-sharing fraction was <5% and was not significantly increased, except in areas with policy intervention. The intervention policy not only led to dramatic increases in the clean energy fraction for heating but also accelerated the clean cooking transition. Higher income, higher education, younger age, less energy/stove stacking and smaller family size positively impacted the clean energy transition.

Report on the 19th international symposium on geo-disaster reduction/high-level academic forum on disaster mitigation and integrated risk defense on the Plateau, 12-15 July 2021, Xining, China.

The joint event of 19th International Symposium on Geo-disaster Reduction (19ISGdR) and High-Level Academic Forum on Disaster Mitigation and Integrated Risk Defense on the Plateau was held on 11-15 July in Xining, Qinghai Province, China, focusing on the theme of "Geological disaster and integrated risk defense". This event consisted of keynote lectures, invited lectures, and Youth forum, which provided a platform for scientists, industrial professionals and young scholars to share their research progress and exchange novel ideas on geo-disaster reduction in a hybrid way of offline and online. A post-symposium field trip for three days was also conducted in the joint area between Qinghai-Tibet plateau and Loess plateau.

Simulation and estimation of future ecological risk on the Qinghai-Tibet Plateau.

Over the past 50 years, temperatures on the Qinghai-Tibet Plateau (QTP) have risen roughly twice as fast as the global average, making it the most unpredictable region of environmental change due to global warming. In this paper, an Environmental Area Index model was developed using data from the Coupled Model Intercomparison Project to assess the ecological risk faced by QTP ecosystems under the influence of climate factors. The results show that ecological risk gradually decreases from northwest to the southeast, and there are different trends in ecological risk for each class in areas with different elevation gradients. As elevation increased, the proportion of potential risk areas gradually decreased, and the proportion of high- and higher-risk areas gradually increased. We predict that in the period 2021-2100, the overall ecological risk change trend on the QTP will not be obvious, but there will be a more obvious change on the vertical gradient. In general, under the existing global climate change scenario, the ecological risk faced by the QTP show a decreasing trend under the influence of climate factors, and the decrease in ecological risks is much higher at higher elevations than at lower elevations.

Homegarden agroecosystems managed by Salar people on Qinghai-Tibet Plateau.

BACKGROUND: Salar is a Turkic-speaking Islamic ethnic group in China living mainly in Xunhua Salar Autonomous County (Xunhua or Xunhua County), Qinghai-Tibet Plateau. Salar people are skilled in horticulture and their homegarden (HG) management. They are regarded as the first people on the Qinghai-Tibet Plateau to practice horticulture, especially manage their HGs, traditional farming systems, and supplementary food production systems. Traditional knowledge of Salar people associated with their HGs always contributes significantly to the local livelihood, food security, ornamental value, and biodiversity conservation. The cultivation of different plants in HGs for self-sufficiency has a long tradition in China's rural areas, especially in some mountainous areas. However, Salar traditional HGs have not been described. The present paper aims to report the features of Salar HGs mostly based on agrobiodiversity and its ecosystem services. METHODS: The methods used in this work included semi-structured interviews and participatory observation. A total of 60 households in three townships, 9 villages were surveyed. There are 4-12 family members in each household, aged from 20 to 86 years old. The homestead size is between 200 and 1200 m2. Plant species cultivated in Salar HGs were identified according to Flora of China. Based on a comprehensive survey of Salar HGs and related to background data, we identified and characterized the most important services and functions provided by Salar HGs. RESULTS: According to primary production systems, there are 4 different types of Salar HGs, including ornamental focus, product focus, dual-purpose and multi-purpose. In total, 108 (excluding weeds and bonsai) plant species were recorded in Salar HGs, within 43 plant families. The most important and frequently used plants are Rosa chinensis, Armeniaca vulgar, Prunus salicina, and Ziziphus jujuba. About 4 to 32 plant species were recorded in each homegarden. We found that the Salar HGs, as a typical agroecosyste, prossess multiple servcices and functions that directly benefit households according to the field investigation. CONCLUSION: This paper reveals the floristic diversity of Salar HGs. It presents useful information in the homegarden agroecosystem of Salar people, such as HG types and species diversity in Salar HGs. Ecosystem functions and services research suggested that the Salar HG agroecosystem provides agroecosystem services mainly related to supply and culture services. Salar HGs are important as food supplement resources, aesthetics symbol, and cultural spaces.

Performance and relationship of four different agricultural drought indices for drought monitoring in China's mainland using remote sensing data.

Increasing frequency and intensity of extreme drought events have harmed the environment, ecosystem, and agricultural productivity. However, the characteristics of agricultural drought in China have not been well understood. The remote sensing (RS) based gridded monthly precipitation, soil moisture, land surface temperature (LST), and normalized difference vegetation index (NDVI) datasets over 1982-2018 were utilized to derive standardized precipitation index (SPI), standardized soil moisture index (SSI), multivariate standardized drought index (MSDI), and vegetation health index (VHI). The variation patterns and trends of SPI, SSI, and MSDI at the 1-, 3-, and 6-month timescales against monthly VHI anomaly were compared to identify the best agricultural drought index in China. The drought variations in the four sub-regions (northwest, north, Qinghai-Tibet area, and south area) were also investigated. The results showed that: (1) Temporal patterns of VHI anomaly were similar to relative soil moisture and slightly different from precipitation. The spatial patterns of MSDI matched with VHI the best than SPI and SSI. (2) All three indices showed positive correlations with VHI at the three timescales. The highest correlation coefficients (r) between MSDI and VHI ranged from 0.25 to 0.67, 0.22 to 0.78, 0.23 to 0.69, and 0.19 to 0.74 in northwest China, north China, Qinghai-Tibet Plateau, and south China, respectively. (3) The connections between monthly VHI and the three drought indices were weaker at the 1-month timescale (0.16 < r < 0.25) than the 3-month (0.39 < r < 0.78) and 6-month (0.26 < r < 0.68) timescales. (4) The VHI significantly increased in most of China except north China. Overall, MSDI showed better performance for monitoring agricultural drought in China's mainland.