Eastern Qinghai-Tibet Plateau Research Articles

Understanding indigenous people's traditional Chinese medicinal plants harvesting preferences to guide sustainable management

Abstract Surging demand for medicinal plant products may lead to unsustainable harvesting practices, which could put pressure on wild populations. Yet little is known about indigenous harvesters' preferences on key traditional Chinese medicinal plant resources, and how these might affect sustainable use and management. We conducted a discrete choice experiment with over 900 native Tibetan harvesters in the eastern Qinghai–Tibetan plateau in China, under a range of complex alternative livelihood, climate and environmental change, and land tenure and customs scenarios. We used random parameter logit model with broad heterogeneity to estimate local Tibetan harvesters' preferences and their willingness to harvest, and latent class logit model to explore distinct within‐population groupings based on shared preferences, for designing possible interventions. We uncovered three key findings with important management implications for medicinal plants. When given a choice, the local harvesters preferred not to harvest any herbs. However, if they opted to harvest, they preferred to harvest flowers and seeds, as compared to roots, and tended to use wooden tool (over the use of bare hands and iron tool). Notably, the degree of compliance with village rules and customs, and ecological worldview interact with targeted plant parts and potential income from harvest to influence their harvesting preferences. Their choices were sensitive to scenario‐based changes to livelihood options. Finally, our study revealed three distinct harvester groups with substantial heterogeneity. Specifically, two groups consisted of over 60% of the interviewed harvesters who appeared to have a strong preference for sustainable practices, while the remaining group lacks this tendency. Overall, our results shed light on the importance of understanding the drivers of harvesting preferences and the heterogeneity of harvesting practices among indigenous people and their cultural and sustainability leanings, providing crucial insights for future sustainable use and management of wild and economically important medicinal plants in the grasslands of Qinghai–Tibetan Plateau and other regions. Read the free Plain Language Summary for this article on the Journal blog.

The paleolacustrine significance of sedimentary nitrogen isotopes: A comparative study of late Holocene records in two lakes on the eastern Qinghai-Tibet Plateau

The bulk nitrogen isotope composition of lacustrine sediments can be a useful proxy of past climatic and environmental changes. We previously reconstructed paleoenvironmental histories recorded in sediments of Lake Ximencuo and Lake Ngoring, both located on the eastern Qinghai-Tibetan Plateau (QTP), using a suite of biogeochemical paleoclimate proxies that included the sedimentary δ15Ntot values. We have revisited the different patterns of δ15Ntot variations in the two lakes and now conclude that their isotopic trends over the last millennium have been controlled by multiple factors. Regional temperature evidently is one potential factor affecting the sedimentary δ15Ntot values, indicating that the lake ecosystems respond to regional temperature changes on a sub-millennial timescale but in indirect and lake-specific ways. The processes involved in the sedimentary δ15Ntot changes appear to be more strongly influenced by the shapes of lake basins and associated hydrologic characteristics that control the origins of nitrogen-containing compounds in the lakes. To help understand the dynamics of nitrogen cycling and nitrogen isotope records in the QTP lakes, we identified two patterns - a terrestrial nitrogen-controlled pattern (TNCP) that is observed in deeper, steep-walled glacial-basin lakes and an aquatic nitrogen-controlled pattern (ANCP) that is observed in shallower, tectonic-basin lakes. We also considered the influences of the “amount effect” and the “temperature effect” on sedimentary δ15Ntot values and their possible operative mechanisms in these montane lakes. We postulate that both patterns are applicable to the QTP lakes, including both glacial and tectonic lakes, and probably to lakes in other regions that have also not experienced significant human disturbance.

Numerical analysis of the impacts of rainfall on permafrost-related slope stability on the Qinghai–Tibet Plateau

Study regionThis study interrogates a landslide in ice-rich permafrost region in the Eastern Qinghai–Tibet Plateau, China. Study focusClimate warming has increased the frequency and intensity of rainfall events, changing hydrothermal processes and the soil mechanical properties, thus affecting slope stability in permafrost region. The purpose of this paper is to elucidate the variations in soil volumetric water content (VWC) which may influence the mechanical properties of unstable slopes in ice-rich permafrost region under different rainfall conditions. New hydrological insights for the regionThis paper integrates the rainfall infiltration boundary conditions and Mohr–Coulomb criterion into a thermo–hydro–mechanical (THM) model and analyzes a landslide case in the permafrost regions. The results show that the THM model can effectively account for the impacts of VWC variation under different rainfall conditions. The influence of rainfall on the VWC diminishes as depth increases, with a more pronounced effect observed at depths less than 1 m. At depths exceeding 1 m, the impact is relatively minor. Under the condition of low-intensity, long-duration rainfall, with accumulated precipitation exceeding 60 mm, the cohesion and internal friction angle decrease to 4.2kPa and 8.1°, respectively, with a deep-layer integral slippage. In contrast, under the condition of high-intensity, short-term rainfall, the accumulated rainfall exceeds 75 mm and the internal friction angle decreases from 39° to 26°, with shallow-layer slippage. The results add on to our understanding engineering problems and periglacial geomorphic processes under the influence of climate warming.

Accuracy Verification of Satellite Products and Temporal and Spatial Distribution Analysis and Prediction of the CH4 Concentration in China

In this study, the spatiotemporal variations in CH4 concentrations in China from 2003 to 2021 are investigated, and their trends are forecasted over the next decade. Based on the seventh edition standard product retrieved by the atmospheric infrared detector (AIRS) at an altitude of 500 hPa, we verified monthly CH4 products using observational data provided by the World Data Center for Greenhouse Gases (WDCGG) from six ground stations in and around China. The correlation coefficients (R values) between the two data sets ranged from 0.68 to 0.92, signifying the ability of AIRS inversion data to represent temporal and spatial changes in surface CH4 concentrations. Additionally, China was classified into three regions (steps) based on terrain, and the changes in CH4 concentrations were assessed from three perspectives: spatial distribution, interannual variation, and seasonal variation. The results revealed that the CH4 concentration decreased with elevation along a topographic gradient, with high-value areas located in the first and second steps, corresponding to the eastern Qinghai–Tibet Plateau, northern Xinjiang Uygur Autonomous Region, and Inner Mongolia Autonomous Region. Over 19 years, the average increase in CH4 concentration has ranged from 65 to 175 ppb. In addition, the CH4 concentrations were higher during summer and autumn and lower during spring and winter. Finally, a SARIMA model was used to predict the near-surface CH4 concentration trend in China over the next ten years, which indicated a continued seasonal increase.

Daily and Seasonal Activity Patterns of Plateau Pikas (Ochotona curzoniae) on the Qinghai-Tibet Plateau, China, and Their Relationship with Weather Condition.

Exploring the activity patterns of small mammals is important for understanding the survival strategies of these animals, such as foraging and mating. The purpose of the present study was to determine the activity of free-living plateau pikas (Ochotona curzoniae) in different months and seasons (cold and warm seasons), with a particular emphasis on the effects of weather condition. Based on a camera-trapping survey conducted from October 2017 to September 2018, we evaluated the activity patterns and activity levels of plateau pikas inhabiting the eastern Qinghai-Tibet Plateau in China. The effects of environmental factors on the activity of plateau pikas were examined using the generalized additive mixed model (GAMM). The results showed that: (1) The plateau pikas exhibited unimodal patterns of activity during the cold season (October-April). During the warm season (May-September), the activity patterns of the plateau pikas were bimodal. Their activity levels were highest in June. (2) During the cold season, their activity levels rose gradually over the course of the day to a peak near noon, and they were not significantly higher after sunrise than they were before sunset. During the warm season, their activity peaks were in the morning and afternoon, and their activity levels were substantially lower after sunrise than they were before sunset. (3) The plateau pikas were more active under conditions with lower ambient temperatures and precipitation during the cold and warm seasons. While relative air humidity was positively correlated with the activity of the plateau pikas during the warm season, wind speed was negatively correlated with the pikas' activity during the cold season. Overall, these results collectively indicate that plateau pikas occupy habitats with cool and less windy microclimates during the cold season, and with cool and moist microclimates during the warm season. Information on the time allocation of pikas' activity levels during different seasons should provide a baseline for understanding their potential for adaptation to climate change.

Stipa baxoiensis (Stipeae, Poaceae), a new species from Qinghai-Tibet Plateau, China

Stipa baxoiensis (Stipeae, Poaceae), a new species from eastern Qinghai-Tibet Plateau, China, is described and illustrated. The new species belongs to S. sect. Regelia and is similar to S. subsessiliflora in the contracted and suberect panicles, but differs mainly by its densely hirsutulous leaf sheath and adaxial surface of leaf blade.

Nitrogen addition increases topsoil carbon stock in an alpine meadow of the Qinghai-Tibet Plateau

Soil carbon (C) sequestration plays a critical role in mitigating climate change. Nitrogen (N) deposition greatly affects soil C dynamics by altering C input and output. However, how soil C stocks respond to various forms of N input is not well clear. This study aimed to explore the impact of N addition on soil C stock and to elucidate the underlying mechanisms in an alpine meadow on the eastern Qinghai-Tibet Plateau. The field experiment involved three N application rates and three N forms, using a non-N treatment as a control. After six years of N addition, the total C (TC) stocks in the topsoil (0–15 cm) were markedly increased by an average of 12.1 %, with a mean annual rate of 20.1 ‰, and no difference was found between the N forms. Irrespective of rate or form, N addition significantly increased the topsoil microbial biomass C (MBC) content, which was positively correlated with mineral-associated and particulate organic C content and was identified as the most important factor that affecting the topsoil TC. Meanwhile, N addition significantly increased the aboveground biomass in the years with moderate precipitation and relatively high temperature, which leads to higher C input into soils. Owing to decreased pH and/or activities of β-1,4-glucosidase (βG) and cellobiohydrolase (CBH) in the topsoil, organic matter decomposition was most likely inhibited by N addition, and this inhibiting effect varied under different N forms. Additionally, TC content in the topsoil and subsoil (15–30 cm) exhibited parabolic and positive linear relationship with the topsoil dissolved organic C (DOC) content, respectively, indicating that DOC leaching might be an important influencing factor for soil C accumulation. These findings improve our understanding of how N enrichment affects C cycles in alpine grassland ecosystems and suggest that soil C sequestration in alpine meadows probably increases with N deposition.

Mapping the forage nitrogen, phosphorus, and potassium contents of alpine grasslands by integrating Sentinel-2 and Tiangong-2 data

Nitrogen (N), phosphorus (P), and potassium (K) contents are crucial quality indicators for forage in alpine natural grasslands and are closely related to plant growth and reproduction. One of the greatest challenges for the sustainable utilization of grassland resources and the development of high-quality animal husbandry is to efficiently and accurately obtain information about the distribution and dynamic changes in N, P, and K contents in alpine grasslands. A new generation of multispectral sensors, the Sentinel-2 multispectral instrument (MSI) and Tiangong-2 moderate-resolution wide-wavelength imager (MWI), is equipped with several spectral bands suitable for specific applications, showing great potential for mapping forage nutrients at the regional scale. This study aims to achieve high-accuracy spatial mapping of the N, P, and K contents in alpine grasslands at the regional scale on the eastern Qinghai-Tibet Plateau. The Sentinel-2 MSI and Tiangong-2 MWI data, coupled with multiple feature selection algorithms and machine learning models, are applied to develop forage N, P, and K estimation models from data collected at 92 sample sites ranging from the vigorous growth stage to the senescent stage. The results show that the spectral bands of both the Sentinel-2 MSI and Tiangong-2 MWI have an excellent performance in estimating the forage N, P, and K contents (the R2 values are 0.68–0.76, 0.54–0.73, and 0.74–0.82 for forage N, P, and K estimations, respectively). Moreover, the model integrating the spectral bands of these two sensors explains 78%, 74%, and 84% of the variations in the forage N, P, and K contents, respectively. These results indicate that the estimation ability of forage nutrients can be further improved by integrating Tiangong-2 MWI and Sentinel-2 MSI data. In conclusion, integration of the spectral bands of multiple sensors is a promising approach to map the forage N, P, and K contents in alpine grasslands with high accuracy at the regional scale. This study offers valuable information for growth monitoring and real-time determination of forage quality in alpine grasslands.

Variation in leaf vein traits of Pinaceae plants on the eastern Qinghai-Tibet Plateau, China.

To explore the adaptative strategies of single-veined plants along the environmental gradient, we collec-ted leaves of 57 Pinaceae species (including Abies, Larix, Pinus and Picea) from 48 sites along a latitudinal gradient (26°58'-35°33' N) on the eastern Qinghai-Tibet Plateau. By measuring three traits of leaf vein, including vein length per leaf area, vein diameter, and vein volume per unit leaf volume, we analyzed the trade-off between vein traits and their relationship with environmental changes. The results showed no significant difference in vein length per leaf area among different genera, but significant difference in vein diameter and vein volume per unit leaf volume. There was a positive correlation between vein diameter and vein volume per unit leaf volume for all genera. There was no significant correlation of vein length per leaf area with vein diameter and vein volume per unit leaf volume. With the increases of latitude, vein diameter and vein volume per unit leaf volume significantly decreased. In contrast, vein length per leaf area did not show a latitudinal trend. Mean annual temperature was the main factor driving the variation in vein diameter and vein volume per unit leaf volume. The relationships between vein length per leaf area and environmental factors were relatively weak. These results indicated that the single-veined Pinaceae plants have a special adaptative strategy to environmental changes through adjusting vein diameter and vein volume per unit leaf volume, which is quite different from complex vein structures such as reticular veins.

Tracing Microbial Production and Consumption Sources of N2O in Rivers on the Qinghai-Tibet Plateau via Isotopocule and Functional Microbe Analyses

Nitrous oxide (N2O), a potent greenhouse gas, is produced in rivers through a series of microbial metabolic pathways. However, the microbial source of N2O production and the degree of N2O reduction in river systems are not well understood and quantified. This work investigated isotopic compositions (δ15N-N2O and δ18O-N2O) and N2O site preference as well as N2O-related microbial features, thereby differentiating the importance of nitrification, denitrification, and N2O reduction in controlling N2O emissions from five rivers on the eastern Qinghai-Tibet Plateau (EQTP). The average N2O concentration in overlying water (15.2 nmol L-1) was close to that in porewater (17.5 nmol L-1), suggesting that both overlying water and sediment are potentially important sources of N2O. Canonical and nitrifier denitrification dominated riverine N2O production, with contribution being approximately 90%. Nitrification is a non-negligible source of N2O production, and N2O concentration was positively correlated with nitrification genetic potential. The degree of N2O reduction ranged from 78.1 to 94.1% (averaging 90%), significantly exceeding the reported values (averaging 70%) in other freshwaters, which was attributed to the higher ratios of organic carbon to nitrogen and lower ratio of (nirS + nirK)/nosZ in EQTP rivers. This study indicates that a combination of isotopic and isotopocule values with functional microbe analysis is useful for quantifying the microbial sources of N2O in rivers, and the intense microbial reduction of N2O significantly accounts for the low N2O emissions observed in EQTP rivers, suggesting that both the production and consumption of N2O in rivers should be considered in the future.

Environmental Gradients and Vegetation Types Alter the Effects of Leaf Traits on the Dominance of Woody Angiosperm Species

Leaf traits can reflect plant photosynthetic capacity, resource utilization strategy and adaptability to the environment. However, whether species’ leaf traits are tightly related to the functioning of their community and how that relationship varies with environmental gradients remain largely unexplored. We measured 6 leaf traits, including petiole fineness (PF), specific leaf area (SLA), leaf area (LA), leaf length–width ratio (LLWR), leaf nitrogen content (LN) and leaf phosphorus content (LP), of 733 populations (415 species) of 19 woody angiosperm communities in the eastern Qinghai–Tibetan Plateau across multiple climatic zones or vegetation types. Through meta-analysis and relative importance analysis, the relationship between leaf traits of species and their community dominance and its change with environments were analyzed. The results showed that species dominance was correlated positively with their LA and LP, suggesting that species with high light interception and resource utilization capacity can easily become dominant species in woody angiosperm communities. Along the altitudinal gradient, the effect of PF and SLA on species dominance increased and changed significantly in their pattern, from positive or nonsignificant in temperate forests to negative in alpine and subalpine shrubs, suggesting that increasing petiole mechanical support and lamina protection cost is a dominant leaf growth strategy in stressful high-altitude environments. Our findings demonstrate that the demand for efficient light acquisition and/or utilization and species adaptability or tolerance to specific environmental stress are key mechanisms by which leaf traits govern community composition and functioning.

An annually laminated stalagmite from the eastern Qinghai-Tibetan Plateau provides evidence of climate instability during the early MIS5e in the Asian summer monsoon

An annually laminated stalagmite from the eastern Qinghai-Tibetan Plateau provides evidence of climate instability during the early MIS5e in the Asian summer monsoon

Does higher demand for medicinal plants lead to more harvest? Evidence from the dual trade of Nardostachy jatamansi and Fritillaria cirrhosa and Tibetan people’s harvesting behavior

IntroductionAs the demand for herbal medicines is surging worldwide, regions of medicinal plants are vulnerable to large-scale and unsustainable exploitation for commercial trade and use. Yet, we still lack the understanding about the relationship between indigenous people harvesting and trade practices of medicinal plants and their influencing factors for possible intervention measures.MethodsHere, we combined qualitative and quantitative methods to survey traders (N = 20) and local harvesters (N = 923) from nine Tibetan townships in Hongyuan county, Sichuan Province, on the eastern Qinghai-Tibetan plateau in China. Specifically, we elucidated the local value chain of medicinal plants trade and harvest of Nardostachy jatamansi and Fritillaria cirrhosa, and explored the factors influencing harvester’s willingness to harvest these plants. Furthermore, we empirically tested the constructs of the COM-B model (Capability, Opportunity, Motivation -Behavior) in predicting the sustainable harvesting behavior of medicinal plants.Results and DiscussionOur results revealed that the trade characteristics of N. jatamansi and F. cirrhosa were contrasting, and the sustainability of the former species was largely dependent on the latter one. Importantly, the traders’ practices were affected by the supply, while the harvesters’ willingness to harvest were mainly influenced by harvest incomes, past harvesting experience, and grassland tenure. Finally, though motivation was not directly affecting harvesting behavior, the harvesters’ ecological worldview indirectly affected their harvesting behavior, particularly through the mediation of the level of compliance of village rules and customs. Overall, our results provided crucial insights for the conservation and sustainable management of the valuable wild medicinal plants.

Morphometrical analyses revealed high diversity of the eastern honey bee (Apis cerana) in mountains and islands in China

The eastern honey bee (Apis cerana) is of great importance for ecosystems and agriculture in Asia, whose diversity has yet to be explored. Previous studies have found a high diversity of A. cerana in mountainous areas or islands. To better understand the morphological diversity of A. cerana, we focused on the eastern Qinghai-Tibet Plateau (QTP), a region with high mountains, Weizhou Island, Yongxing Island and Hainan Island, much of which lacks systematic investigation of honey bee diversity. Five sampling sites in the plain were also selected as references. A total of 140 colonies of A. cerana were collected from 9 localities in QTP, 3 localities in islands, and 5 localities in plain. We used standard morphometry and geometric morphometrics to assess the level of diversity, in which principal component analysis and discriminant analysis were conducted. The results revealed the A. cerana populations from QTP and islands were differentiated from the plain populations. Moreover, two populations from QTP and one from Yongxing Island showed significant divergence. Our study provided insights into the A. cerana diversity and provides information for the effective conservation of A. cerana genetic resources in China.

Alarm Calling in Plateau Pika (Ochotona curzoniae): Evidence from Field Observations and Simulated Predator and Playback Experiments

Acoustic communication plays a vital role in passing or sharing information between individuals. Identifying the biological meaning of vocal signals is crucial in understanding the survival strategies of animals. However, there are many challenges in identifying the true meaning of such signals. The plateau pika (Ochotona curzoniae) is a call-producing mammal endemic to the Qinghai-Tibet plateau (QTP) and considered a keystone species owing to its multiple benefits in alpine rangeland ecosystems. Previous studies have shown that plateau pikas emit alarm calls as part of their daily activities. However, only field observations have been used to identify these alarm calls of the plateau pika, with no attempts at using playback experiments. Here, we report the alarm calling of plateau pikas through field observations as well as simulated predator and playback experiments in the Eastern QTP from 2021 to 2022. We found that both female and male adults emitted alarm calls, the signals of which comprised only one syllable, with a duration of 0.1-0.3 s. There were no differences in the characteristics between the observed alarm calls and those made in response to the simulated predator. The duration of the alarm call response varied with altitude, with plateau pikas living at higher altitudes responding at shorter durations than those at lower altitudes.

Leaf traits divergence and correlations of woody plants among the three plant functional types on the eastern Qinghai-Tibetan Plateau, China.

Leaf traits are important indicators of plant life history and may vary according to plant functional type (PFT) and environmental conditions. In this study, we sampled woody plants from three PFTs (e.g., needle-leaved evergreens, NE; broad-leaved evergreens, BE; broad-leaved deciduous, BD) on the eastern Qinghai-Tibetan Plateau, and 110 species were collected across 50 sites. Here, the divergence and correlations of leaf traits in three PFTs and relationships between leaf traits and environment were studied. The results showed significant differences in leaf traits among three PFTs, with NE plants showed higher values than BE plants and BD plants for leaf thickness (LT), leaf dry matter content (LDMC), leaf dry mass per area (LMA), carbon: nitrogen ratio (C/N), and nitrogen content per unit area (Narea), except for nitrogen content per unit mass (Nmass). Although the correlations between leaf traits were similar across three PFTs, NE plants differed from BE plants and BD plants in the relationship between C/N and Narea. Compared with the mean annual precipitation (MAP), the mean annual temperature (MAT) was the main environmental factor that caused the difference in leaf traits among three PFTs. NE plants had a more conservative approach to survival compared to BE plants and BD plants. This study shed light on the regional-scale variation in leaf traits and the relationships among leaf traits, PFT, and environment. These findings have important implications for the development of regional-scale dynamic vegetation models and for understanding how plants respond and adapt to environmental change.

Applying Artificial Cover to Reduce Melting in Dagu Glacier in the Eastern Qinghai-Tibetan Plateau

Global warming has accelerated during the past decades, causing a dramatic shrinking of glaciers across the globe. So far, the attempts to counterbalance glacial melt have proven to be inadequate and are mostly limited to a few glacial landscapes only. In the present study, a scientific glacier protection experiment was conducted at the Dagu Glacier site. Specifically, the study site was the Dagu Glacier No. 17, situated 4830 m a.s.l. The study involved a deliberate verification of the feasibility and effectiveness of using geotextile covers on small glaciers located at high altitudes between August 2020 and October 2021. The observations revealed that the mass loss in the area covered with geotextiles was, on average, 15% lower (per year) compared to that in the uncovered areas combining field campaigns, terrestrial laser scanning, and unmanned aerial vehicle. The reason for this could be that the albedo of the geotextile is higher than that of the glacier surface. In addition, the aging of geotextiles causes a decline in their albedo, leading to a gradual decline in the effectiveness of the resulting glacier protection. It was indicated that geotextiles could be effective in facilitating the mitigation of glacier ablation, although the cost-related limitations render it difficult to upscale the use of artificial cover. Nonetheless, using active artificial cover could be effective in the case of small glaciers, glacier landscapes, and glacier terminus regions.

Temporal Activity Patterns of Sympatric Species in the Temperate Coniferous Forests of the Eastern Qinghai-Tibet Plateau.

Temporal niche partitioning is an important strategy for sympatric species or populations when utilizing limited resources while minimizing competition. Different resource availability across seasons may also influence the intensity of competition, resulting in a varied temporal niche partitioning pattern between species. These competitive interactions are important drivers for the formation of biodiversity patterns and species coexistence on the eastern Qinghai-Tibet Plateau. To clarify these interspecies relationships among sympatric species, we carried out a camera trap survey from 2017 to 2020. We deployed 60 camera traps in the temperate coniferous forests of the eastern Qinghai-Tibet Plateau. We analyzed the daily activity patterns of birds and mammals to reveal the temporal niches and seasonal relationships among the species-specific activity rhythms. The results are summarized as follows: (1) Eight major species, including mammals and birds, have different temporal peak activity rhythms to reduce intense competition for resources. (2) The activity rhythm of a species varies seasonally, and the competition among species is more intense in the warm season than in the cold season. (3) Among 15 pairs of competitor species, seven pairs had significantly different coefficients, with higher winter values than summer values, perhaps due to the abundance of resources in summer and the scarcity of resources in winter causing intensified competition. Among the predators and prey, the summertime coefficients were higher than those in winter, perhaps due to the need to replenish energy during the summer breeding season. The main purpose of animals in winter is to survive the harsh environment. Our results provide important information on temporal and interspecies relationships and contribute to a better understanding of species-coexistence mechanisms.

Coupled Coordination Analysis between Urbanization and Eco-Environment in Ecologically Fragile Areas: A Case Study of Northwestern Sichuan, Southwest China

In China, rapid urbanization in recent decades has led to increasingly serious ecological and environmental problems, threatening sustainable development. Thus, a clear understanding of the relationship between urbanization and eco-environment is the basis for achieving regional sustainable development. However, despite the current global explosion of research interests on this topic, few studies have focused on ecologically fragile areas. To fill this gap, taking Aba Autonomous Prefecture in the eastern Qinghai-Tibet Plateau as a case study, we explored the relationship between urbanization and eco-environment from 2001 to 2018 using a coupled coordination degree model. The results show that the urbanization level and eco-environmental quality in Aba Prefecture achieved stable and continuous improvements from 0.202 to 0.428 and 0.372 to 0.422, respectively. Moreover, the coupling degree between them ranged from 0.524 to 0.652, indicating that the study area had transformed from uncoordinated development in the initial stage to transformation development in the final stage. Additionally, over the 18 years, the coordinated state of urbanization and eco-environment improved, with the coordinated level increasing from reluctant to moderate coordination after 2011. Lastly, we confirmed that urbanization in Aba Prefecture had an overall positive effect on the local eco-environment, although it gradually decreased as urbanization progressed. These findings have important implications for political decision-makers to achieve high-quality development in ecologically fragile areas.

Carbon and nutrient limitations of soil microbial metabolism in Quercus aquifolioides forest ecosystems along a precipitation gradient on the eastern Qinghai-Tibetan Plateau

Carbon and nutrient limitations of soil microbial metabolism in Quercus aquifolioides forest ecosystems along a precipitation gradient on the eastern Qinghai-Tibetan Plateau