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Agricultural water accounts for more than 80% of the available water in arid areas. Agricultural activities have a great impact on surface water and groundwater. If the impact of agricultural activities on hydrochemistry is not prevented, the risk of water quality change in arid areas may be greatly intensified. Based on the hydrochemical data of the whole Shiyang River Basin from April 2014 to October 2019, this paper analyzes the impact of agricultural activities on hydrochemistry in the basin. The results show that (i) in the middle and lower reaches of farmland with high intensity of agricultural activities, the ion concentration of groundwater in summer and autumn is significantly higher than that in winter and spring due to the influence of irrigation; (ii) the runoff ion concentration in the backflow of the river reaches recharged by irrigation water is significantly higher than that of other reaches; (iii) due to strong evaporation, different types of reservoirs will lead to an overall increase in ion concentration, which is more obvious in plain reservoirs and river tail lakes. In addition, the reservoirs have a certain removal effect on nitrates.

Global changes and human activities have significantly altered water cycle processes and water resource patterns in inland river basins in arid zones. New tools are needed to conduct more comprehensive and scientific assessments of basin water cycle processes and water resource patterns. Based on GRACE satellite and Landsat data, this study investigated terrestrial water storage changes and surface water area in the Shiyang River Drainage Basin from 2002 to 2021. It explored the effects of climate change and water conservancy construction on terrestrial water storage changes in the basin. The results of the study show that, although the surface water quantity in the Shiyang River basin has increased in the past 20 years, the overall decreasing trend of terrestrial water storage in the basin of the Shiyang River has an interannual decreasing rate of 0.01 cm/a. The decreasing trend of water storage in the midstream and downstream areas is more prominent. The change in precipitation controls the change in water storage in the Shiyang River Drainage Basin. Artificial water transfer has changed the spatial distribution of water resources in the basin of the Shiyang River. However, it still has not completely reversed the trend of decreasing water storage in the middle and lower reaches of the Shiyang River.

In the middle and lower reaches of inland river basins of arid regions, human-intensive exploitation directly determines the distribution patterns of plants in arid areas and further determines the patterns of water use and the water cycle in arid regions. However, human activities on vegetation water utilization and the influence of the water cycle process and mechanism are not clear. In this study, seven observation systems were set up to collect samples in the mountainous, oasis and desert areas of the Shiyang River Basin, an arid inland river in central Asia. In order to quantitatively assess the contribution of different potential water sources to plants, stable isotopes of various water bodies in different geomorphic units of the basin were analyzed. The results showed that precipitation and soil water were the main sources of forest trees in mountainous areas, and the farmland vegetation in the middle and lower reaches of the oasis mainly absorbed soil water supplied by irrigation. The desert area forms vegetation in the ecological water transport area, and vegetation mainly absorbs soil water, lake water and groundwater formed by ecological water transport. On the whole, the water use patterns of plants in mountainous areas are not affected by human activities fundamentally, the oasis area is mainly affected by irrigation activities, and the inland river terminal lake area is mainly affected by ecological water transport. Human activities determine the water use patterns in the middle and lower reaches of inland rivers in arid areas.

A thorough understanding of the processes and driving factors of ion migration, dilution, and enrichment in arid inland river basins is the basis for implementing water resources management. In this study, we analyzed the water chemistry of streamflow, groundwater, and precipitation and the behavior of main elements in the Shiyang River Basin by means of the hydrochemical diagram and multivariate statistical analysis. The spatial variation of water chemistry was obvious, and the conversion between different water bodies was frequent. The ions migrated from the mountain area to the oasis and desert and accumulated near the terminal lake finally. There were obvious differences in hydrochemistry between surface water and groundwater. From the mountain to the basin, the hydrochemical type of surfer water has varied, and the hydrochemical type of groundwater has changed from Ca-Cl type to Na-Cl type. The hydrochemistry of the basin was controlled by silicate weathering. However, the influence of water-rock interaction on surface water and groundwater was different, and the surface water was more complex. Significantly, agricultural activities and sewage discharge had a negative impact on the water environment. Interbasin water transfer (IBWT) was a form of external ions input from outside the basin, which affected the chemical characteristics of surface water in the lower reaches to a certain extent. In arid areas, human impact on water chemistry needs to be paid attention. These results are helpful to strengthen the understanding of the relationship between different regions and different water bodies in the arid basin.

Increasing evidence shows that facilitative interactions between species play an essential role in coastal wetland ecosystems. However, there is a lack of understanding of how such interactions can be used for restoration purposes in saltmarsh ecosystems. We therefore studied the mechanisms of reciprocal facilitative interactions between nativeannual plants, Suaeda salsa, and burrowing crabs, Helice tientsinensis, in a middle‐elevation saltmarsh (with generally high plant density and moderate tides) in the Yellow River Delta of China. We investigated the relationship between the densities of the plants and crab burrows in different seasons. Then, we tested whether and how saltmarsh plants and crabs indeed facilitate each other in a series of field and laboratory experiments. Finally, we applied the results by creating a field‐scale artificial approach for microtopographic modification to restore a degraded saltmarsh. We found that the density of plant seedlings in spring was positively correlated with the density of crab burrows in the previous autumn; moreover, the density of crab burrows was correlated with the density of plants in summer. The concave–convex surface microtopography created by crabs promoted seed retention and seedling establishment of saltmarsh plants in winter and spring. These plants in turn facilitated crabs by inhibiting predators, providing food and reducing physical stresses for crabs in summer and autumn. The experimental removal of saltmarsh plants decreased crab burrow density, while both transplanting and simulating plants in bare patches promoted crabs. The microtopographic modification, inspired by our new understanding of the interactions between saltmarsh plants and crabs, showed that these degraded saltmarsh ecosystems can be restored by a single ploughing intervention. Synthesis . Our results suggest a reciprocal facilitation between annual plants and burrowing crabs in a middle‐elevation saltmarsh ecosystem. This knowledge yielded new restoration options for degraded coastal saltmarshes through the one‐time ploughing initiation of microtopographic variation, which could promote the re‐establishment of ecosystem engineers and lead to the efficient recovery of pioneer coastal vegetation and associated fauna.

Birds are a very important part of the coastal wetland ecosystem, and they are also ecosystem engineers who can affect the abiotic environment and biological processes through their own behavior. Understanding the ecosystem engineering effect of birds in the coastal wetland ecosystem plays an important role in the ecological restoration of coastal wetlands. Through field investigation, the effects of pit digging and foraging behavior of coastal birds led by Grus grus and Anas poecilorhyncha on the topography and soil environmental physical and chemical indicators in the vegetation degradation area were studied, so as to promote the restoration of Suaeda salsa vegetation. The results showed that birds’ digging and foraging behavior in the degraded vegetation area changed the micro topography and soil environment in the degraded area, resulting in a significant decrease in soil hardness and soil salinity, while soil moisture content and soil carbon and nitrogen nutrition index were significantly higher than those in the degraded flat area without the influence of birds; in addition, the pit micro terrain environment improved by bird activities can significantly improve the seed retention, seedling colonization and adult survival of Suaeda salsa, and effectively promote the restoration of Suaeda salsa in the vegetation degradation area. Inspired by the change of microtopography by birds to promote vegetation restoration, it is proposed that we can try to artificially simulate and transform the microtopography environment in the degraded area, and promote the vegetation restoration in the degraded area of coastal wetlands through human intervention, which has important guiding significance for the ecological restoration of coastal wetlands.

Vehicular honk behavior is not uncommon in real traffic. Meanwhile, with the advent of sensors and communication technology, the real-time traffic state can be readily available to drivers. With such information, drivers can estimate the future traffic status and take countermeasures in advance. In this study, we propose a new lattice hydrodynamic model by jointly considering the vehicular honk and driver’s predictive effect. In the linear stability analysis section, neutral stability curve of the model is given, and the modified Korteweg de Vries (mKdV) equation is obtained in nonlinear stability analysis. The kink–antikink soliton solution is obtained by solving the above mKdV equation, which can be used to describe the phase transition of the traffic flow near the critical point. Results show that the honk and the driver’s predictive effect contribute to the traffic flow stability.

Scientific understanding of regional wind speed variation characteristics and driving mechanisms is of great practical significance to the management and rational utilization of wind energy resources, ecological protection and governance, and sustainable development of agriculture. Taking the Shiyang River Basin in inland river basin of monsoon marginal zone as the study area, this paper analyzed wind speed changes and influencing factors at different time and space scales. The results showed that, first of all, the annual average wind speed showed a downward trend as a whole in Shiyang River Basin, and the change of spring wind speed and the decreasing frequency of daily max-wind speed above Grade 5 were the main contributors. The turning point of annual average wind speed was consistent with that in spring and autumn (1981) and earlier than that in winter and summer (1982). Secondly, as far as the wind speed change tendency rate is concerned, before the turning point, Yongchang area had the largest decline rate with obvious “2000 m effect”, while after the turning point, Wuwei Basin had the largest rise rate with obvious “basin effect”. Focusing on the downstream desert oasis region, the sand-driving wind speed showed a decreasing trend as a whole, and showed a “cliff-like” decline after 1988. The rising trend of sand-driving wind speed after 2014 will pose greater challenges to ecological governance. Finally, under the background of unbalanced global warming, the wind speed changes in different periods were driven by the circulation system changes. In 1970–1981, the decline of the wind speed was the result of the combined action of Arctic Oscillation and Asia Polar Vortex. However, after 1981, it was affected by North Atlantic Oscillation, Asian Meridional Circulation, Tibet Plateau Circulation, India-Burma Trough, Western Pacific Subtropical High and Northern Hemisphere Subtropical High.

Understanding plant traits in response to physical stress has been an important issue in the study of coastal saltmarshes. For plants that reproduce both sexually and asexually, whether and how seedlings (sexual reproduction) and clonal ramets (asexual reproduction) may differentially respond to tidal inundation is still unclear. We investigated the growth and morphology of sexual and asexual propagules of an exotic saltmarsh plant (Spartina alterniflora) along a gradient of tidal submergence in the Yellow River Delta. Our results showed that the density, height and basal diameter of clonal ramets or sexual seedlings increased with tidal inundation. The patch amplification edge clonal ramets are superior than patch center plants. The differences response of plants to tidal inundation highlight the sensitivity of S. alterniflora to future tidal regime shifts and can help predict and evaluate the impacts of changes in inundation conditions due to sea level rise, coastal erosion and human activities.

Macrobenthos are a key constituent of coastal salt marsh ecosystems and have often been used as sensitive indicators of the environment quality. In this study, field investigations in vegetated regions and adjacent bare patches of low, middle and high marshes were conducted to explore whether and how vegetation influence the macrobenthos distribution in different saltmarsh zones along coastal topographic gradients. Results showed that vegetation positively or negatively influenced macrobenthos mainly by changing their environment in different saltmarsh zones, as there were different degrees of physical stresses and food supply for the macrobenthos from the low to the high marsh. In the low marsh, no major differences in macrobenthos indices between the bare and vegetated sediments were found, yet density and biomass of the molluscs were higher in the bare patches. In the middle marsh, vegetation promoted the biomass and diversity indices but not the density and species richness of the macrobenthos, and vegetation was beneficial for some types of crustaceans but was detrimental for some types of polychaetes. In the high marsh, vegetation promoted the biomass, density, and species richness of the macrobenthos compared to those of adjacent bare patches. Coastal topographic gradients also had effects on macrobenthos distribution consistently with different habitat preferences and ecological niches, and the low marsh had the highest species richness, Shannon diversity, Pielou evenness and Margalef richness. This study also provided scientific implications for the management and restoration of the ecosystems in different intertidal saltmarsh zones.

Invasion of habitat-modifying nonnative species and alteration of ecosystem engineer by exploitation are two of the dominant human impacts on natural ecosystem functioning. The effects of these co-occurring ecosystem engineers may act simultaneously and vary independently depending on ambient environmental conditions they modify. Using a saltmarsh ecosystem with continuing invasion of nonnative cordgrass and aggregation of native bivalve shells, we tested whether the ecosystem engineering effects of shell aggregation on macroinvertebrates depended on the plants due to their ability to trap shell debris. We found habitats covered with shell aggregation and vegetated cordgrass significantly increase the biodiversity but decrease the biomass of macroinvertebrates comparing to the tidal bare flats, whereas no differences were detected among shell covered, cordgrass vegetated and their coexistent habitats. Our study highlights the importance of considering multiple, potentially conflicting management goals, which may require flexibility and trade-offs to integrate nonnative and native resources into ecosystem management.

Biogeomorphological processes and structures (BPS) can affect plant growth and community structure and promote landscape complexity in ecosystems. However, there is a lack of understanding of how BPS facilitates seedling establishment and distribution of annual plants and promotes the success of coastal restoration. We studied the relationships between seedling establishment of a native annual plant species (Suaeda salsa) and BPS resulting from crabs and plants in a middle elevation salt marsh with moderate tides (where inhabited generally high density of plants and crabs) in the Yellow River Delta of China. While there were many crabs but fewer plants in lower elevation areas with more frequent and stronger tides; and in higher elevation areas with weaker tides there were both fewer crabs and plants. Investigations and field manipulation experiments of microtopography, crabs and plants were conducted to determine if and how these BPS influenced seedling establishment and distribution under tidal influence in the middle elevation salt marshes. Results demonstrated that biogeomorphological structures, mainly concave hollows generated by crab burrowing and concave hollows around plant roots and stems under tidal influence, were associated with the trapping of seeds and influenced the establishment and distribution of seedlings. Additionally, upon senescence, maternal plants with unreleased seeds lodged on the ground and influenced seed retention and seedling establishment. The artificial concave hollows that were created experimentally also trapped many seeds and facilitated seedling establishment. Experimental plantings and creation of artificial hollow microtopography attracted crabs that created burrows, resulting in a positive feedback on seedling establishment. We used information obtained from the experimental component of the study to conduct a hollow microtopography manipulation to successfully restore degraded salt marshes. Understanding the associations between seedling establishment and biogeomorphological processes provides important insights for the utilization of natural or human ecosystem engineering to restore coastal vegetation ecosystems.

The dry deposition of particular matters from atmosphere to ecosystems is an undesirable consequence of this pollution while the deposition process is also influenced by different land use types. In current study, concentration of fine particles, coarse particles and meteorological data were collected during the daytime in an artificial forest, wetland and a water surface in the Beijing Olympic Park. Dry deposition velocity, fluxes and vegetation collection were calculated by different models and the results were compared. The results show: (1) the deposition velocity onto the forest canopy was higher than which onto the wetland and the water surface and the velocity varied in different seasons; (2) the fine particles deposited most in the winter while the coarse particles was in the spring; (3) the vegetation collection rates of fine particles were lower than coarse particles, and the forest collected more PMs than the wetland plants.

The competition-to-stress hypothesis suggests that some competitively disadvantaged species are excluded from higher inundation estuaries due to abiotic stress (high flooding level) and from lower inundation estuaries by competition. How abiotic and biotic stress interactions affect plant growth and whether competition intensity and importance are stable along environmental gradients is a controversial subject. We explored the influence of two factors, and we clarified that inundation stress and invasion competition are the main reasons leading to the traits exhibited by target plant Suaeda salsa and population presence changes. Our results indicated that when the flooding height exceeded 13.4 cm, the S. salsa mortality rate was 90%-100%. At the lower flooding heights (13.4 cm), the S. salsa mortality rate when neighboring plants were present was 77.7%-100%, whereas, without neighbors it was 30.9%-83.7%. The invader Spartina alterniflora inhibited S. salsa plant height by 48%-77%, whereas the S. alterniflora inhibited S. salsa density by 11%-98% and reduced its biomass by 50.5%-90.1%. The changes in competition intensity and importance showed that the S. alterniflora had a distinct impact from the early germinant period to growing period (from May to July), finally stable no differences along the flooding height in the maturity period. At the same flooding level, the analysis of above and belowground competition by S. alterniflora showed that aboveground and belowground competition are the main causes of individual S. salsa inhibition. Our results confirm the competitive stress hypothesis, which is that competition shapes individual traits and population presence in the context of abiotic stress. This conclusion can guide the management and protection of native plants under biological invasion in a stressful environment.

Increasing evidence shows that herbivores can facilitate plant growth and maintain the resistance of plant communities to trophic consumption in a variety of ecosystems. However, the positive effects of herbivores on annual saltmarsh plants in coastal ecosystems are relatively understudied. In this study, field investigations and manipulative experiments were conducted to explore whether and how microtopographical modification by the herbivorous crab Helice tientsinensis stimulates the growth of the saltmarsh plant Suaeda salsa. Results showed that, despite grazing on S. salsa, H. tientsinensis can promote density, total biomass, average plant height, average root length, and average biomass through burrowing-generated concave-convex microtopography, which can improve the edaphic environment (decreased soil hardness and salinity, and increased soil moisture content, oxidation-reduction potential, and carbon and nitrogen content), and provide plants more clustered growth opportunities that could facilitate positive intraspecific plant interactions. This study can provide scientific guidance for ecosystem restoration in coastal intertidal saltmarshes.

Ecosystem engineers that affect other organisms by creating, modifying, maintaining or destroying habitats have received widespread attention. Understanding natural ecosystems and the way in which ecosystem engineers shape the environment is important to ecological restoration based on key ecosystem processes. Increasing studies has shown that crabs in intertidal salt marsh can act as ecosystem engineers, affecting the geomorphological processes and spatial heterogeneity of tidal flat. In this study, field investigations and manipulative experiments were conducted to explore how crab burrowing activity affects intertidal microtopography and soil carbon and nitrogen in the intertidal salt marshes. The results showed that crab burrowing activity is one of the key factors influencing concave-convex microtopography, which could intercept plant detritus and subsequently influencing the retention and accumulation of soil carbon and nitrogen. When compared to areas of flat microtopography with few or no crab burrows, soil organic carbon content (SOC), soil inorganic carbon content (SIC), total carbon content (TC), and total nitrogen content (TN) in adjacent areas of concave-convex microtopography with high density crab burrows were all significantly higher. Artificial simulation of ecosystem engineering processes could also change the geomorphological features of tidal flats and improve the retention and accumulation of soil carbon and nitrogen, which could also attract more crabs to burrow and settle down, then generate and maintain the concave-convex microtopography. Taken together, the results of this study provide scientific and effective implication and guidance for the restoration of coastal salt marshes.

Urban residential land suitability evaluation is an important part in the general land use planning. Its result guides us to the optimum living environment. Grounded on evaluation features, the paper established an evaluation index system consisting of 32 indexes in 4 layers. A case study of a residential area in Wenzhou is made to further practice this comprehensive evaluation, the result of which helps improve the living environment in the related area.

Particulate matter (PM) pollution has been increasingly becoming serious in Beijing and has drawn the attention of the local government and general public. This study was conducted during early spring of 2013 and 2014 to monitor the concentration of PM at three different land surfaces (bare land, urban forest, and lake) in the Olympic Park in Beijing and to analyze its effect on the concentration of meteorological factors and the dry deposition onto different land cover types. The results showed that diurnal variation of PM concentrations at the three different land surfaces had no significant regulations, and sharp short-term increases in PM10 (particulate matter having an aerodynamic diameter

Since being designated as an international tourist island, Hainan has become an overwhelmingly favored choice of real estate investment. This paper first constructed Hainan residential quarter function factor index system, then evaluated relevant factors, and finally solved the problem of factor importance ranking. In this specific case, the software MATLAB was used to facilitate AHP calculation. The evaluation results have guiding and referential value to both real estate developers and residential consumers.

To increase the knowledge on the particulate matter of a wetland in Beijing, an experimental study on the concentration and composition of PM10 and PM2.5 was implemented in Beijing Olympic Forest Park from 2013 to 2014. This study analyzed the meteorological factors and deposition fluxes at different heights and in different periods in the wetlands. The results showed that the mean mass concentrations of PM10 and PM2.5 were the highest at 06:00-09:00 and the lowest at 15:00-18:00. And the annual concentration of PM10 and PM2.5 in the wetland followed the order of dry period (winter)>normal water period (spring and autumn)>wet period (summer), with the concentration in the dry period significantly higher than that in the normal water and wet periods. The chemical composition of PM2.5 in the wetlands included NH4(+), K(+), Na(+), Mg(2+), SO4(2-), NO3(-), and Cl(-), which respectively accounted for 12.7%, 1.0%, 0.8%, 0.7%, 46.6%, 33.2%, and 5.1% of the average annual composition. The concentration of PM10 and PM2.5 in the wetlands had a significant positive correlation with relative humidity, a negative correlation with wind speed, and an insignificant negative correlation with temperature and radiation. The daily average dry deposition amount of PM10 in the different periods followed the order of dry period>normal water period>wet period, and the daily average dry deposition amount of PM2.5 in the different periods was dry period>wet period>normal water period.

The future satellite communication systems should be able to accommodate the integrated services with a variety of applications and fulfill Quality of Service requirements. Regarding to the limited and costly resources, a novel resource allocation in a multi-frequency time-division multiple access (MF-TDMA) is proposed. In order to optimize packing performance, the users with more time slots are packed first. The algorithm's performance of delay and channel utilization can be validated through the simulation for different types of traffic. We further compare the performances of classical schemes. The theoretical analysis and simulation results show that that new algorithm can efficiently improve channel utilization in satellite resource allocation, especially when the number of satellite terminals is large. The algorithm is simple and easy to implement in satellite communication system.

Praat is an excellent speech software which makes it possible to visualize the EFL pronunciation teaching. Such specific values as formant, fundamental frequency, intensity and duration have been extracted for a better analysis of sound waves in respect of segmental, accentuation and intonation. Therefore, pronunciation errors are clearly identified. The application of Praat revives classroom teaching and helps improve the reliability and validity of pronunciation evaluation. A new idea for self-study and self-testing is further developed.

Walking is an essential traffic mode in urban life. It often conflicts with driving. Pedestrian crossing traffic is where the primary conflict lies. The paper presents a case study of Wenzhou City, aiming to find the major problems endangering the local traffic safety. Possible reasons have been figured out and corresponding countermeasures have been put forward. There are some suggestions: a public education for traffic safety should be made to raise the safety awareness of Wenzhou citizens; the visibility of walking traffic is supposed to be ensured and Wenzhou original crossing gestures be popularized; separation equipment needs to be properly built and more road-section crosswalk signals be installed; more tri-dimensional crossing facilities and pedestrian refuge islands could be invested in and the distance between crossing facilities could be well controlled. The case study of Wenzhou presents academic and practical implications to similar studies in other domestic cities.

The traffic calming measures are applied in many countries all over the world. They are well-systemized and having good effects. The domestic related research, however, is much less developed. Thus, this article introduced the measures of traffic calming volume control and speed control in overseas studies and illustrated them with figures and description. Then, the article gave a demonstration in the application of traffic calming measures. At last, it offered a suggestion to the study of traffic calming and traffic safety in China. The measures may be adopted in roads of areas, like domestic residential quarters, new investment and development zones and university towns. They are likely to help ensure road safety in China.

Surveillance camera, as an important component of intelligent transportation system, has had a big development in China. The study adopted the algorithm of graphic minimal covering to figure out economical and reasonable locations for surveillance cameras distribution in small and medium-sized city road networks. The minimal covering algorithm was further applied in a case study of an urban industrial park in which the optimal distribution of the cameras was finally found. The application of the algorithm lays a theoretical foundation for a well-designed distribution of surveillance cameras in small-medium city road networks. It is proved to be practical and useful.