Permafrost soils store large amounts of carbon, which are highly susceptible to human activities and climate warming. With widespread human infrastructure, roads have expanded rapidly worldwide, significantly impacting the permafrost soils. However, the influence of highway construction on soil organic carbon (SOC) in frozen ground remains poorly understood. Here, we investigated changes in SOC in alpine grasslands along a 1700 m elevational gradient spanning seasonally frozen ground (SFG) and permafrost regions on the Qinghai-Tibetan Plateau. We found SOC storage (0-30 cm depth) significantly reduced in highway-disturbed grasslands compared to undisturbed areas. Notably, SOC storage loss in permafrost was 51.7% higher on average compared with SFG. SOC storage loss increased significantly with elevation. In particular, when the elevation surpasses 4287 m, the slope of SOC storage loss with altitude is amplified by more than two times. This abrupt point of elevation coincided with the transition from SFG to permafrost. We also found that climatic factors were the dominant predictors of SOC storage loss in the SFG, while anthropogenic factors, including grazing and human intensity, played more significant roles in permafrost. Our findings demonstrated that highway construction in permafrost regions significantly reduces SOC storage, which is lost substantially more in permafrost than in SFG. This pattern aligns closely with a distinct elevation threshold separating the two frozen ground types. We emphasize that such SOC loss may exacerbate permafrost carbon-climate feedbacks under warming. Consequently, we highlight the importance of considering potential SOC loss when planning largescale infrastructure development in high-elevation permafrost regions.

Priority effects refer to the phenomenon where species that arrive earlier gain a competitive advantage, thereby influencing the establishment and performance of the species that arrive later. While the role of priority effects in shaping plant communities has been recognized and applied in the restoration of grasslands, little is known about their influence on the microbial communities in the soil. In this study, we investigated how plant priority effects affected the community composition of the soil microbes and their temporal dynamics. A sequential sowing experiment was conducted using Elymus nutans and Tibetia himalaica in a glasshouse. Soil samples were collected at three key stages of plant growth and analyzed using high-throughput sequencing. The results showed that the early arrival of T. himalaica significantly increased the microbial diversity and altered the community composition. Although the effects on microbial diversity diminished over time, the overall community structure remained distinct. Moreover, the bacterial and fungal communities had divergent temporal responses to the priority treatments of the plants. These findings deepen our understanding of plant-soil-microbe interactions and offer practical insights to optimize the sequences of assembling plants during the ecological restoration of grassland.

Fe-OC is crucial for SOC preservation in the global ecosystem. However, there is still significant uncertainty in the determination methods of Fe-OC, and these methods are often not calibrated to each other, making the Fe-OC content by different methods impossible to compare. Here, Fe-OC is analyzed by the CBD method and the SD method from 45 soils from different land types (e.g., wetland, grassland, and forest) to compare and analyze the uncertainty and influencing factors between the two methods. Our results showed that the Fe-OC contributions to SOC (fFe-OC) measured by CBD and SD methods were significantly lower in the wetland ecosystem than in grassland and forest ecosystems. The Fe-OC content and fFe-OC in the grassland ecosystem was significantly higher using the CBD method compared to the SD method, with no significant difference between the methods in wetland and forest ecosystems. The random forest model revealed that Fe-OCCBD content was mainly affected by C/N, Clay%, and TC, whereas SOC, total nitrogen, and soil inorganic carbon were the main influences on Fe-OCSD. Taken together, our findings highlight the importance of incorporating ecosystem types and soil properties into soil carbon estimation models when predicting and estimating Fe-OC and its contribution to SOC.

Elucidating the mechanisms underlying microbial biomass and extracellular enzyme activity responses to the seasonal precipitation regime during foliar litter decomposition is highly important for understanding the material cycle of forest ecosystems in the context of global climate change; however, the specific underlying mechanisms remain unclear. Hence, a precipitation manipulation experiment involving a control (CK) and treatments with decreased precipitation in the dry season and extremely increased precipitation in the wet season (IE) and decreased precipitation in the dry season and proportionally increased precipitation in the wet season (IP) was conducted in a subtropical evergreen broad-leaved forest in China from October 2020 to October 2021. The moisture, microbial biomass, and extracellular enzyme activities of foliar litter from two dominant shrub species, Phyllostachys violascens and Alangium chinense, were measured at six stages during the dry and wet seasons. The results showed that (1) both IE and IP significantly decreased the microbial biomass carbon and microbial biomass nitrogen content and the activities of β-1,4-glucosidase, β-1,4-N-acetylglucosaminidase, acid phosphatase and cellulase in the dry season, while the opposite effects were observed in the wet season. (2) Compared with those of IE, the effects of IP on foliar litter microbial biomass and extracellular enzyme activity were more significant. (3) The results from the partial least squares model indicated that extracellular enzyme activity during foliar litter decomposition was strongly controlled by the foliar litter water content, microbial biomass nitrogen, the ratio of total carbon to total phosphorus, foliar litter total carbon, and foliar litter total nitrogen. These results provide an important theoretical basis for elucidating the microbial mechanisms driving litter decomposition in a subtropical forest under global climate change scenarios.

It is challenging to restore Tibetan Plateau vegetation once it has been damaged. Highway construction, necessary for economic development, have significant negative impacts on the composition, structure, and functioning of the Qinghai-Tibet Plateau alpine grassland ecosystem. However, there is uncertainty regarding the extent of ecosystem damage in this region, such as whether quarries dug during highway construction may be restored and how recovery varies with increasing altitude. We conducted a transect survey of 39 quarry-restored grasslands reseeded with Elymus nutans and adjacent paired natural grasslands on the Gongyu and S308 highways on the Qinghai-Tibet Plateau (2800–5100 m above sea level). By comparing the community height, coverage, and species composition between restored and natural grasslands, we evaluated the degree of recovery and altitudinal gradient pattern of the grassland community and explained the limiting factors that led to the differences in recovery. After two-year restoration, quarry coverage and species composition were not restored to the degree of natural grassland. As altitude increased, the coverage recovery degree of quarry recovery community continued to decline, and the dissimilarity of community composition between the restored and natural grasslands was rising. We showed a breaking point at ca. 4100 m where recovery degree dropped dramatically, indicating a threshold for highway construction. The soil nutrients in quarry decreased significantly with increasing altitude. Structural equation modelling indicated that increasing altitude decreased the coverage of quarry by reducing temperature and soil nutrients. Due to the limitations of single species sowing, low temperature and nutrient availability, the effect of recovery decreased with increasing altitude. Therefore, we propose that during highway construction in the permafrost of the Qinghai-Tibet Plateau, quarries should avoid operation at high altitudes. When the altitude exceeds a certain height (e.g., 4100 m in this study), we do not recommend excavating quarries to destroy alpine grasslands.

Aims Grasslands in the Qinghai-Tibet Plateau play an important role in preserving ecological security and high biodiversity in this region. However, the distribution of the composition and structure of plant community and the mechanism by which it maintains itself in this region is still poorly understood. Methods Here, we designed 195 grassland plots in 39 grassland sites along an approximately 1700-m elevation gradient on the Northeastern Qinghai-Tibet Plateau. Important findings We found that the grassland community height decreased significantly with the increase of elevation, while community coverage did not demonstrate significant changes. With the increase of elevation, the plant species richness (alpha diversity) increased significantly, but the community variability (beta diversity) decreased significantly. The constrained clustering analysis suggested that the alpha- and beta-diversity in the grasslands transformed gradually with elevation, and three discontinuous points (based on community structure) were observed at elevation of 3640, 4252 and 4333 m. Structural equation modeling (SEM) indicated that the increase of precipitation and the decrease of temperature significantly positively influenced alpha diversity, which was negatively correlated with beta diversity. These results demonstrate that the community composition and structure presented a quantitative-to-qualitative change along this elevational gradient on the Qinghai-Tibet Plateau.

It is very difficult to recover the alpine grassland on the Qinghai Tibet Plateau after being destroyed. However, the demand for economic construction forced the government to build highways on the Qinghai Tibet Plateau, leaving behind many quarries. However, it is uncertain whether these quarries can be restored and the extent of restoration. This study conducts a transect survey of 39 quarry-restored grasslands reseeded with Elymus nutans and adjacent natural grasslands on two recently constructed highways on the Qinghai–Tibet Plateau from 2800 to 5100 m above sea level. The first data set is the community survey data set of height, in which the rows describe the species names in the sample plots, the sample plots shown in the list and duplicates. The second data set is the community survey data set of coverage, in which the rows describe the species names in the sample plots, the sample plots shown in the list and duplicates. We believe that the height and coverage were not enough to evaluate the restoration, and the community species composition of the restored grassland was an important indicator to evaluate the restoration.

The side ditch is a longitudinal ditch set up on both sides of the road cutting to collect and remove precipitation from the road surface, road shoulder and side slope. It is the most common drainage facility in highway construction. However, the existing side ditches are generally wide, large, and deep, with a single structure, and poor coordination with the environment along the line. For this reason, this paper proposes a new type of permeable ecological side ditch structure design. Under the premise of ensuring the basic functions of the side ditch, this design effectively solves the problem that the edge of the side ditch is susceptible to erosion due to accumulated rainwater or frost heave in the alpine areas with high groundwater level. At the same time, to maximize the strength of the side ditch and enhance its ecological function.

Determining the temperature sensitivities of the decomposition rates of leaf litter and fine root is important for predicting the impact of climate warming on above- and belowground carbon (C) cycles in forest ecosystems. However, the responses of leaf and root decomposition rates to temperature have rarely been examined together. Here, we present the results of paired leaf litter and fine root decomposition experiments at four forest sites spanning 32° latitude in eastern China. The mean annual soil temperature explained the variances of the decomposition rates of the leaf litter (kLeaf, R2 = 0.95) and fine root (kFine root, R2 = 0.86) across the different biomes well and exerted a positive effect on the kLeaf: kFine root ratio. As a result, the sensitivity of the decomposition rate to temperature was significantly higher in the leaf litter (Q10 = 2.17 ± 0.07) than in the fine root (Q10 = 1.40 ± 0.06). The results of structural equation models indicated that the initial C:nitrogen (C:N) ratio exhibited negative effects, and phosphorus (P) cycling related enzymes activity exhibited positive effects on the kFine root when the effects of temperature were controlled. Even when the variables of these biotic factors were added, the soil temperature still exerted a dominant effect on the kLeaf. Our results suggest that temperature directly influences the kLeaf but indirectly affects the kFine root through litter quality and soil decomposers.

Evaluation on the emission reduction effect of the carbon trading pilot is very important for China's energy conservation and emission reduction. This paper uses the generalized linear model to evaluate the emission reduction effects of China's carbon trading pilot. The results show that existing Carbon Trading Pilot slow down the relative increase of carbon emissions in the pilot areas, and their emission reduction effect is relatively obvious before and after the establishment of the carbon trading pilots from 2010 to 2012. However, as time goes by, the emission reduction effects in the adjacent period become weak. Therefore, it is necessary to implement the national carbon market as soon as possible to promote the energy saving and emission reduction of national province scale.

In view of the lack of mandatory statistics on energy consumption of transportation infrastructure at the national level, the energy consumption index system of Qinghai highway transportation infrastructure was established based on the analytic hierarchy process by using fuzzy synthetic evaluation method. And the calculation method of Qinghai highway transportation infrastructure was established based on the calculation results of the unit energy consumption coefficient of each classification index. This work offers reference for the rapid evaluation of the energy consumption of Qinghai highway transportation infrastructure.

Extensive grazing activity is threatening the alpine grassland of the Qinghai-Tibetan Plateau. Evidence has shown that grazing exclusion may change the composition, structure, and functions of grassland ecosystems. However, such effects depend on the intensity and duration of exclusion. We explored the effects of short-term (2 and 4 years) and long-term (9 and 11 years) grazing exclusion on plant height, coverage, and diversity and community heterogeneity in the alpine grassland of the Qinghai-Tibetan Plateau. We found no difference in plant diversity between short-term grazing exclusion and control. However, long-term grazing exclusion reduced species richness and increased the Simpson dominance index. This decrease in plant species richness was mainly attributable to the decrease in common species richness (defined as species with a relative coverage of 1∼5%). In addition, community heterogeneity (coefficient of variation, CV) was significantly higher in long-term grazing exclusion than in controlled plots. Structural equation modeling (SEM) demonstrated that long-term grazing exclusion increased the community heterogeneity mainly by reducing species diversity. These results suggest that the effects of grazing exclusion on the composition, structure, and community spatial heterogeneity of the alpine grassland ecosystem are dependent on exclusion duration. Grazing activity may maintain the high biodiversity and community stability of the alpine grassland in the harsh environment of the Qinghai-Tibetan Plateau.

Wetlands play an important role in water conservation and biodiversity accumulation. The crossing highways may cut off the water flow relationship between wetland patches, and further influence wetland ecosystems. In this study, we investigated the situation of wetlands based on field survey, aerial photographic and remote sensing image interpretation along two roads (Gongyu Expressway and S308 road) in the Sanjiangyuan Part. We found that there were only two places exhibits a different wetland image at the either side of the road. Road construction basically did not obstruct wetlands. It was also noted that by improving existing culverts, measures could be taken to avoid or alleviate such phenomena.

There are different components of carbon (C) pools in a natural forest ecosystem: biomass, soil, litter and woody debris. We asked how these pools changed with elevation in one of China’s ecologically important forest ecosystem, i.e. beech (Fagus L., Fagaceae) forests, and what were the underlying driving factors of such variation. The four C pools in nine beech forests were investigated along an elevational gradient (1095–1930 m) on Mt. Fanjingshan in Guizhou Province, Southwest China. Variance partitioning was used to explore the relative effects of stand age, climate and other factors on C storage. In addition, we compared the four C pools to other beech forests in Guizhou Province and worldwide. The total C pools of beech forest ecosystems ranged from 190.5 to 504.3 Mg C ha–1, mainly attributed to biomass C (accounting for 33.7–73.9%) and soil C (accounting for 23.9–65.5%). No more than 4% of ecosystem C pools were stored in woody debris (0.05–3.1%) and litter (0.2–0.7%). Ecosystem C storage increased significantly with elevation, where both the biomass and woody debris C pools increased with elevation, while those of litter and soil exhibited no such trend. For the Guizhou beech forests, climate and stand age were found to be key drivers of the elevational patterns of ecosystem and biomass C storage, while for beech forests globally, stand age was the most important predictor. Compared to beech forests worldwide, beech forests in Guizhou Province displayed a relatively higher biomass C accumulation rate, which may be explained by a much higher precipitation in this area. The present study provides basic data for understanding the C budgets of Chinese beech forests and their possible roles in regional C cycling and emphasizes the general importance of stand age and climate on C accumulation.

本研究以海北高寒草甸为研究对象,比较了2、4、9、11、20年5个围栏封育处理与各自配对的放牧样地(对照)的生物量碳储量.结果表明:短期(2和4年)围封对植被碳储量无显著影响(P＞0.05),但长期(9、11和20年)围封显著降低了植被碳储量(P＜0.05).围封改变了不同功能群对地上生物量碳储量的相对贡献;短期围封增加了杂类草的地上生物量碳储量,而长期围封显著降低了禾草、豆科和莎草的地上生物量碳储量(P＜0.05).长期围封主要通过降低地下生物量碳储量(根系,0-50 cm 土壤深度),进而降低植被碳储量.研究结果显示,长期围封不利于青藏高原高寒草甸植被碳储量的积累,尤其不利于地下根系碳储量的固存.

Behavioral response experiment of fish to mirror images is one of the main ways to test the social and aggressive behavior. The behavior changes of Zrbrafish Danio rerio in tanks contain different number of mirrors was tested in this study. The result indicated that the latency of zebrafish from entry tank which contains mirrors to start moving ( P < 0.05) and their frequency of midline crossing ( P < 0.001) were all lower than control group (contains no mirror), and decreased with increasing numbers of mirrors. The total swimming time of zebrafish in tank contains mirrors increased with increasing numbers of mirrors and significantly higher than control group ( P < 0.001). Additionally, the time spent of zebrafish in side that contains mirrors significantly higher than the reverse side ( P < 0.05), and this difference degree increased with increasing numbers of mirrors.

For better understanding the phosphorus (P) cycle, it is essential to distinguish the contents of different P speciation in sediments. In the study, the content of total phosphorus (TP) in the sediments ranged from 88.80 to 227.56 μg·g -1 , with an average of 138.42 μg·g -1 . The content of inorganic phosphorus (IP) ranged from 84.21 to 224.26 μg·g -1 , accounting for 88.74%-98.55% of the TP content, which was the main occurrence form in the intertidal sediments of the Yellow River Delta. the contents of phosphorus fractions in surface sediments were 37.06 to 106.35 μg·g -1 for detrital phosphorus (De-P), 2.99 to 34.39 μg·g -1 for exchangeable phosphorus (Ex-P), 5.27-106.06 μg·g -1 for iron bound phosphorus (Fe-P). On the whole, the existing forms of inorganic phosphorus could be ranked as follows: De-P > Fe-P > Ex-P > authigenic phosphorus (Au-P). The regression analysis between TOC content and various forms of phosphorus showed that TOC content was negatively correlated with De-P.

Tourists are the main users of the park, whose spatial and temporal distribution and behavioral characteristics are the most real reflection of the construction of the park environment. Tourists in Beihai Park were selected as the research object. Through field investigation and interview investigation, the main behavior characteristics of tourists in different time and space in winter were studied. Finally, from the perspectives of tourists relation with time and space, we analyze the existing problems, understand the causes of these phenomena, and then put forward the corresponding countermeasures and suggestions, and make suggestions on the construction and management of such parks.

Tianjin Qilihai wetland is an important wetland nature reserve in north China, which has important ecological value. Over the last few decades, the Qilihai wetland has been developed by human on a large scale, and the natural ecosystem has been seriously disturbed by human activities. In this study, principal component analysis was conducted on 7 indicators that may have potential impacts on the Qilihai wetland from 2013 to 2017 to assess the threat of human activities to the wetland area. The results show that from 2013 to 2017, the impact of human activities on the Qilihai wetland is increasing year by year, among which the industrial development, transportation and the increase of human activities around the wetland may be the main threat for the wetland.

Due to the influence of human factors and natural factors, the oviposition grounds and living environment of fish have been seriously damaged, and the decline of fishery resources is obvious. In recent years, artificial fish nests are widely served as a good means to restore fisheries resources and their degraded habitats, summarizes the materials, structure, nesting methods and existing problems for artificial fish nest, according to the artificial fish nest which is complicated to make, has a short service life and the existing artificial fish nest only aiming at the shortcomings of the herbaceous oocytes, we designed a compound artificial fish nest. The complex artificial fish nest consists of a frame, which is provided with two kinds of soft and hard egg adhesive medium to provide ecologic spawning conditions for grass spawning, gravel spawning and water spawning fish whose spawning ground is damaged, so as to increase and improve the population structure and quantity of wild fish.