Sand Fixation Research Articles

Effects of soft rock on soil properties and bacterial community in Mu Us Sandy Land, China.

Soft rock is a new material that could be used for the improvement of Mu Us Sandy Land, China. It can be utilized for wind prevention and sand fixation, both of which are of great importance to ecological restoration aims and cultivated land replenishment in desert areas. Four treatments with different compound ratios of soft rock and sand—0:1 (CK), 1:5 (P1), 1:2 (P2), and 1:1 (P3)—were studied. Fluorescence quantitative PCR (qPCR) and high-throughput sequencing were used to analyze the structure and diversity of the bacterial community in the compound soil and its relationship with physical and chemical parameters in the soil. The results showed that in comparison to CK treatment, soil organic carbon (SOC), total nitrogen (TN), and NH4+-N increased significantly in the P1 treatment; available phosphorus (AP), available potassium (AK), and NO3−-N increased significantly in the P3 treatment. The bacterial gene copy number with P3 treatment was highest, showing a significant increase of 182.05% compared with the CK treatment. The three bacterial groups with the highest relative abundance at the phylum level were Actinobacteria, Proteobacteria, and Chloroflexi, accounting for more than 70% of the total population. The bacterial α diversity showed the same trend, the diversity and abundance indices of the P1 and P3 treatments were the highest, and the β diversity showed that the community structure of the two groups in these treatments were similar. norank_f__Roseiflexaceae and Gaiella (belonging to Actinobacteria) significantly differed with differing compound ratios in each treatment. NO3−-N, NH4+-N and SOC were the main factors affecting bacterial community structure, and had a significant positive correlation with Gaiella abundance. These species are known to play an important role in stabilizing the soil structure of sandy land. Overall, 1:5 and 1:1 compound soil mixtures were beneficial towards the microbial community of sandy land, which plays an important role in biological sand fixation. This study provides an important theoretical basis for the supplementation of arable land area and the improvement of sandy land productivity, and has a good promotion prospect.

Full-Length Transcriptomics Reveals Complex Molecular Mechanism of Salt Tolerance in Bromus inermis L.

Bromus inermis L. (commonly known as smooth bromegrass) is a grass species with high nutritional value, great palatability, cold tolerance, and grazing resistance, which has been widely cultivated for pasture and sand fixation in northern and northwestern China. Salt stress is a main environmental factor limiting growth and production of smooth bromegrass. In this study, we performed PacBio Iso-Seq to construct the first full-length transcriptome database for smooth bromegrass under 300 mM NaCl treatment at different time points. Third-generation full-length transcriptome sequencing yielded 19.67 G polymerase read bases, which were assembled into 355,836 full-length transcripts with an average length of 2,542 bp. A total of 116,578 differentially expressed genes were obtained by comparing the results of third-generation sequencing and second-generation sequencing. GO and KEGG enrichment analyses revealed that multiple pathways were differently activated in leaves and roots. In particular, a number of genes participating in the molecular network of plant signal perception, signal transduction, transcription regulation, antioxidant defense, and ion regulation were affected by NaCl treatment. In particular, the CBL-CIPK, MAPK, ABA signaling network, and SOS core regulatory pathways of Ca2+ signal transduction were activated to regulate salt stress response. In addition, the expression patterns of 10 salt-responsive genes were validated by quantitative real-time PCR, which were consistent with those detected by RNA-Seq. Our results reveal the molecular regulation of smooth bromegrass in response to salt stress, which are important for further investigation of critical salt responsive genes and molecular breeding of salt-tolerant smooth bromegrass.

Reinforcement Mechanism and Engineering Application of Weak Tailing Pond Beach by Soilbag Method

In light of the engineering characteristics of fine-grained tailings, such as their high moisture content, high compressibility, difficult deposition, and difficult consolidation, and based on the summary and analysis of the experience of tailing dam construction in China and abroad, a new comprehensive treatment technology suitable for dam construction on a weak beach, which is composed of strengthening foundation with the soilbag, subdam stabilization, and collaborative drainage, is proposed. Taking a dam construction project on the weak beach of a tailing pond in China as the research object and through the study of the reinforcement mechanism of the soft beach treated using the soilbag method, it can be seen that the soilbag body has the mechanism of strength growth by sand fixation and water permeability and constraint formation and can achieve an overall stable effect of extrusion and silt replacement, stacking and surcharge, and flexible embedding in a weak beach. Using this method, combined with relevant monitoring technology, a good demonstration of dam construction speed of up to 30 m/a and a safe dam construction height of up to 60 m on a weak beach surface is achieved in a tailing dam construction project, which provides a good reference for the design and construction of fine tailing dam engineering and the cooperative disposal of adverse geological conditions.

Key Areas of Ecological Restoration in Inner Mongolia Based on Ecosystem Vulnerability and Ecosystem Service

Inner Mongolia is located in China’s arid and semi-arid regions, with sensitive and fragile ecosystems at risk of increased desertification, necessitating ecological restoration. However, economic resources for large-scale ecological restoration are often scarce, so it is vital to identify key areas for ecological restoration. Previous desertification research has focused mainly on the condition and changes in soil or vegetation. However, not all changes in soil or vegetation directly impact humans. New perspectives are increasingly needed to bridge the gap between biophysical and human well-being. We construct a framework to identify priority restoration areas based on ecosystem services and ecosystem vulnerability over a long time series. The results show that: (1) soil conservation services in northeast and southwest Inner Mongolia have degraded. Sand fixation services in central and eastern Inner Mongolia have shown a degradation trend. Habitat quality has been generally stable and sporadic in the past 20 years. (2) The areas with higher ecosystem vulnerability are concentrated in the northeast, mainly due to higher climate exposure and climate sensitivity but relatively lower climate resilience in the northeast. (3) Compared with the results of ecological restoration areas identified based on the trends of traditional vegetation indicators (fractional vegetation cover and net primary productivity), we found a greater proportion of land in northeastern Inner Mongolia in need of restoration. Additionally, there was identified a decreased restoration proportion in southwestern Inner Mongolia to ensure the self-restoration and regulation of desert ecosystems, which is conducive to realizing nature-based solutions.

Identification of driving forces for windbreak and sand fixation services in semiarid and arid areas: A case of Inner Mongolia, China

Soil wind erosion is a global problem that leads to increasingly serious regional land degradation, where the need for windbreak and sand fixation services (WSFS) is substantial. Inner Mongolia plays an important role in global semiarid and arid areas and the severe land degradation resulting from soil wind erosion warrants an urgent solution. However, the mechanism of influence of various driving factors on windbreak and sand fixation services is still not fully studied. In this paper, the revised wind erosion equation (RWEQ) model was used to synthesize the monthly spatiotemporal dynamics of soil wind erosion modulus (SWEM) and WSFS in Inner Mongolia from January 2000 to February 2020 from a semi-monthly scale. The influencing factors of WSFS were examined from both natural and anthropogenic aspects. Results show that over the past 20 years, the average SWEM in Inner Mongolia was 118.06 t ha−1 yr−1, the areas with severe wind erosion were mainly concentrated in the desert areas in the southwest of Inner Mongolia, and the forests in the northeast suffered less soil wind erosion. Meanwhile, the average WSFS was 181.11 × 108 t yr−1, with the high-value areas mainly located in major deserts, sandy land, and the area bordering Mongolia in the north and the low-value areas mainly located in the densely forested northeast and the Gobi Desert in the northwest. Both SWEM and WSFS showed a clear downward trend and a certain periodicity over the past 20 years. WSFS showed two peaks a year (April and October). Among the natural factors, precipitation and NDVI showed a significant correlation with WSFS and were identified as the main driving factors of WSFS, whereas temperature had no significant correlation. Among the anthropogenic factors, farming and animal husbandry intensity and GDP showed a positive correlation with WSFS, whereas population showed a negative correlation. These four types of factors were identified as socio-economic factors that drive WSFS. Meanwhile, WSFS did not show any significant correlation with the administrative area. Land use change contributed to a large proportion of WSFS change, thereby suggesting that the intensity of human activities is another central driver of WSFS.

Effects of Mixed Decomposition of Pinus sylvestris var. mongolica and Morus alba Litter on Microbial Diversity.

Pinus sylvestris var. mongolica is widely planted in China as a windbreak and sand fixation tree. To improve the current situation of large-scale declines of forested areas planted as P. sylvestris var. mongolica monocultures, we investigated the biological and microbial effects of stand establishment using mixed tree species. The interactions during the mixed decomposition of the litter and leaves of different tree species are an important indicator in determining the relationships among species. In this experiment, a method of simulating the mixed decomposition of P. sylvestris var. mongolica and Morus alba litter under P. sylvestris var. mongolica forest was used to determine the total C, total N, and total P contents in the leaf litter, and the microbial structures were determined by using Illumina MiSeq high-throughput sequencing. It was found that with samples with different proportions of P. sylvestris var. mongolica and M. alba litters, the decomposition rate of P. sylvestris var. mongolica × M. alba litter was significantly higher than that of the pure P. sylvestris var. mongolica forest, and the microbial community and composition diversity of litter in a pure P. sylvestris var. mongolica forest could be significantly improved. The possibility of using M. alba as a mixed tree species to address the declines of pure P. sylvestris var. mongolica forest was verified to provide guidance for pure P. sylvestris var. mongolica forests by introducing tree species with coordinated interspecific relationships and creating a mixed forest.

Exploring the Diversity and Antibacterial Potentiality of Cultivable Actinobacteria from the Soil of the Saxaul Forest in Southern Gobi Desert in Mongolia.

Saxaul (Haloxylon ammodendron) is the most widespread plant community in the Gobi Desert in Mongolia, which plays important roles in wind control, sand fixation and water conservation. Investigations of soil-derived actinobacteria inhabiting in the saxaul forest in Gobi Desert in Mongolia have been scarce. In this study, biodiversity of culturable actinobacteria isolated from soil of the saxaul forest in Southern Gobi Aimak (Southern Gobi Province) of Mongolia was characterized and their potential to produce compounds with antibacterial activities was assessed. A total of 172 actinobacterial strains were recovered by culture-based approaches and were phylogenetically affiliated into 22 genera in 13 families of seven orders. Forty-nine actinobacterial isolates were selected to evaluate the antibacterial activities and their underlying mechanism of action was screened by means of a dual-fluorescent reporter assay (pDualrep2). Twenty-three isolates exhibited antagonistic activity against at least one of the tested pathogens, of which two Streptomyces strains can attenuate protein translation by ribosome stalling. Combinational strategies based on modern metabolomics, including bioassay-guided thin-layer chromatography (TLC), UPLC-QTOF-MS/MS based structural annotation and enhanced molecular networking successfully annotated chloramphenicol, althiomycin and granaticin and their derivatives as the antibacterial compounds from extracts in three Streptomyces strains, respectively. This work demonstrates that UPLC-MS/MS-based structural identification and enhanced molecular networking are effective strategies to rapidly illuminate the bioactive chemicals in the microbial extracts. Meanwhile, our results show that the saxaul forest in Mongolia Gobi Desert is a prospective source for discovering novel actinobacteria and biologically active compounds.

Spatiotemporal change of beneficiary area from wind erosion prevention service in the Ulan Buh Desert in 2008 and 2018

The Ulan Buh Desert is one of the eight deserts in China that provides wind erosion prevention service (i.e., the ecosystem; vegetation, production, and construction activities that promote sand fixation). It is significant for the construction of the national ecological barrier, and the protection of the ecological security in the Yellow River and North China. In this study, we selected two representative years (2008 and 2018) and quantified wind erosion prevention service from the Ulan Buh Desert using the RWEQ model. Meanwhile, the HYSPLIT model was used to simulate the spatial flow process from the service supply area to the beneficiary area and to determine its scope. The specific dust reduction amount in the beneficiary area was then calculated. The energy and the time-space relation of wind erosion prevention service in the areas that receive benefits from Ulan Buh Desert were compared before and after implementing environmental restoration measures. The results showed that: (1) the total amount of wind erosion prevention in the Ulan Buh Desert in 2018 was 2.12 × 1010 kg, which was 5.17 times higher than that in 2008; (2) in 2018, the distribution density of the flow path of wind erosion prevention service was lower than that in 2008, and the flow paths in each year were concentrated in the beneficiary areas with the path distribution frequency of less than 10%; (3) the total dust reduction in the downwind area of the Ulan Buh Desert in 2018 was higher than that in 2008, totaling 15.54 million tons. Inner Mongolia Autonomous Region and Shanxi Province had the most significant amount of dust reduction.

Ectomycorrhizal Fungi Associated With Pinus sylvestris var. mongolica Were Altered by Soil Environments With Aging Plantation in a Semi-arid Desert

Pinus sylvestris var. mongolica (P. sylvestris) is a pioneer afforestation species for wind and sand fixation in northern China. However, most plantations have undergone unprecedented degradation since the early 1990s. Ectomycorrhizal (EcM) fungi are expected to be substantially related to the degradation of P. sylvestris plantations; however, the direct evidence for this remains unclear. For this purpose, we investigated variation among EcM fungal communities associated with P. sylvestris root samples of three age groups (half-mature, near-mature, and mature) in Mu Us Desert. Our results found a total of 72 EcM fungal operational taxonomic unit (OTU) belonging to Basidiomycota (63) and Ascomycota (9). The EcM fungal community is highly enriched in Rhizopogon, Tuber, Tomentella, and Inocybe, and the variations of their abundance mainly contribute to community differences. The diversity index and fungal species richness showed increasing trends toward the mature forest but did not reach a significant level (p > 0.05). The main factors that affected the dominant EcM fungal community were URE, INV, and SOC, but for the whole EcM fungal community, the effects of soil environments with plantation aging are not significant (p > 0.05). Understanding the effects of environmental factors on the structuring of the EcM fungal communities is critical to sustainable forest management in the future.

Straw checkboard or Afforestation?—Assessment and comparison of combined benefits of two typical sand fixing models

Land desertification and sandstorms have been affecting cities worldwide on the edge of sandstorms, so humans have been seeking for ways to strengthen their defenses against wind and sand. High water retention capacity can improve human well-being in sandy areas. Several measures and cases have been already developed. To systematically find the differences between different ecosystem restoration models according to integrated benefits (e.g., ecological, economic and social benefits), this paper proposes an effective technical methodology to quantitatively identify sand control projects in a certain area. With the Southern edge of Tengger Desert-Shapotou in China as an example, this paper uses land use change and NDVI change rates to identify areas of wind and sand management. In addition, this paper uses actual evaporation (ET), soil moisture (SM), temperature vegetation dryness index (TVDI) and sand fixation service to compare the advantages and disadvantages of two typical sand management models in China according to their wind and sand control benefits, resource conservation, as well as socio-economic benefits. As indicated by the results, the straw checkboard engineering model has sustainable ecological and socio-economic benefits in water retention, cost consumption, as well as wind and sand control. Besides, the afforestation model achieves higher ecological benefits in the short term, whereas it has higher operating costs and poor sustainability, which makes this model difficult in maintaining ecological stability. On the whole, both types of sand control projects show their advantages and disadvantages in wind and sand control functions, resource recycling and socio-economic benefits. Furthermore, fast-growing afforestation combined with straw checkboards is capable of sustainably resisting wind and sand attacks and preventing land desertification. Accordingly, the finding of this paper can be referenced widely for wind and sand control.

Desert soilization: Let scientific principles and facts speak

Desert soilization: Let scientific principles and facts speak

Grassland Ecological Protection Monitoring and Management Application Based on ZigBee Wireless Sensor Network

Grassland plays a key role in human production and life, especially in the protection and improvement of the natural environment, which cannot be replaced by other ecosystems, such as maintaining water and soil, preventing wind and sand fixation, maintaining carbon balance, affecting climate change, and producing biological products,.. More importantly, contemporary society attaches great importance to the development of agriculture and animal husbandry. Protecting and nurturing grassland plants and animals, maintaining biodiversity, rational grazing, and maintaining the sustainable development of the grassland ecological environment have become the top priorities. In view of the current serious grassland degradation and the decline of livestock carrying capacity, this paper proposes a grassland environmental monitoring system based on the ZigBee wireless sensor network. The system consists of a grassland wireless monitoring network and a remote PC, which realizes real-time and remote monitoring of environmental information, such as air temperature and humidity, light intensity, and rainfall that affect the growth of grassland pastures. Based on the requirements of the agricultural field data monitoring system, the overall framework of the system was designed and built. The system mainly includes two parts: the ZigBee wireless sensor network subsystem and the remote management software subsystem, and data communication is realized between the two through the Ethernet system data exchange protocol. Among them, the ZigBee wireless sensor network subsystem is deployed in the grassland area and mainly realizes the functions of real-time collection, processing, and wireless transmission of grassland data. The remote management software subsystem is mainly used for data reception, storage, and display and can maintain communication with the gateway node to support real-time monitoring of grassland data by remote browsers.

Analyzing the Interrelationships among Various Ecosystem Services from the Perspective of Ecosystem Service Bundles in Shenyang, China

An understanding of the relationships among multiple ecosystem services (ES) facilitates ecosystem management and decision-making. The study of ES bundles can well explain the complex interactions between different ES in a region. Shenyang is a significant economic development and food production area in Northeast China, with a diverse range of ES types. In this study, we quantified eleven ES from Shenyang, China (two provisioning services, eight regulating services, and one cultural service). The trade-offs and synergies among ES were analyzed by Spearman’s correlation analysis. The ES bundles were identified using principal component analysis and k-means cluster analysis. Finally, the random forest method was employed to identify the driving factors affecting the ES bundles. The results showed: (1) all ES in Shenyang improved between 2000 and 2019; (2) the most obvious trade-off was found between sand fixation and water conservation; (3) the ES in the study region could be clustered into five different ES bundles which were primarily affected by land-use type; and (4) social-ecological factors largely explained and predicted the formation and distribution of ES bundles. The study provides reference information for the management and optimization of Shenyang’s ecosystems and land use regulation.

Chemical Composition and Insecticidal Properties of Essential Oil Obtained from Artemesia songarica Schrenk

Artemisia songarica Schrenk is a dominant sand fixation plant growing in the People's Republic of China. At present, there are rare studies on the chemical composition and biological activity of A. songarica. The chemical composition of the original oil was analyzed by gas chromatography-mass spectrometry, and 16 compounds were determined. The main compounds were bisabolol oxide II (28.7%), nerolidol (18.6%), bisabolol (12.9%), bisaboloxide A (10.0%), and spathulenol (6.0%). The contact toxicity and repellent activity of A. songarica essential oil and four selected compounds (bisabolol, geranyl butyrate, nerolidol, and santalol) were assessed against Tribolium castaneum Herbst and Liposcelis bostrychophila Badonnel. Bioassays showed that the crude essential oil exhibited strong insecticide and repellent activities against both pests. Santalol possessed the strongest contact toxicity (50% lethal dose [LD50] = 1.29 μg per adult) against T. castaneum. Nerolidol, santalol, and geranyl butyrate showed fair contact activity against L. bostrychophila. In particular, geranyl butyrate exhibited outstanding activity (LD50 = 11.53 μg/cm2). In addition, all of the four compounds did not detect a difference between compounds and the positive control (P > 0.05) against two pests at five tested concentrations. These results indicated that A. songarica and its selected compounds could be used as prospective insecticidal and repellent agents for further development and use.

Non-linearity impacts of landscape pattern on ecosystem services and their trade-offs: A case study in the City Belt along the Yellow River in Ningxia, China

Exploring the impacts of landscape pattern on ecosystem services (ESs) and their trade-offs could provide a new way to improve ESs without largely altering land use types. Using the City Belt along the Yellow River in Ningixa (CBYN) as a case study, we quantified five critical ESs (one provision service of crop production, three regulating services of carbon sequestration, nutrient retention and sand fixation, and one cultural service of recreational opportunity) in 1989–2019 through CASA model, InVEST model and empirical equations. Then we calculated landscape pattern metrics at landscape and class level through Fragstats 4.3 across multiple scales and quantified their impacts on each ES and ES trade-offs through random forest analysis, self-organizing mapping analysis and multivariable regression tree. The results suggested that 3 km is more suitable for analyzing the impacts of landscape pattern on ESs in the CBYN. The nonlinear relations between landscape pattern metrics and each ES were fitted with adjusted R2 ranging from 0.26 to 0.51, indicating the significant but limited impacts of landscape pattern on ESs. Specially, landscape-level metrics of CONTAG, SHDI and FRACMN have higher impacts on ESs than class-level ones. Significant synergies existed among agricultural production, carbon sequestration and nutrient retention, except in mountain region with higher or lower fragmentation. Sand fixation has synergy relations with the former three ESs, which would be altered in situations with higher or lower diversity. Our results provide a new direction for land use management to achieve high-quality development without largely altering existing land use situation.

Evaluation and optimization of ecosystem services under different land use scenarios in a semiarid landscape mosaic

Ecosystem services are usually influenced by physical land use changes and climate changes. The significant land use changes and polices in Inner Mongolia mainly include urban development and the ecological restoration programs of Forest Protection, the Grain for Grass and Vegetation Recovery. This study used the Dyna-CLUE model to simulate 2030 land use changes in the Central and Western Inner Mongolia, and then explored key ecosystem services and the ESs-Balanced index under four land use scenarios with the above changes. Compared with the urban development scenario, Vegetation Recovery increases NPP, soil conservation, sand fixation, the surface and bottom soil moisture by 10.84 %, 0.76 %, 4.35 %, 1.52 % and 0.12 % respectively, but it decreases water yield by 6.56%. The Grain for Grass Program increases NPP (1.12 %), soil conservation (0.43 %) and sand fixation (3.96%) at the expense of other ecosystem services, while Forest Protection only increases NPP and the surface soil moisture narrowly. The study further provided the spatially explicit land use optimization by comparing the ESs-Balanced index under four scenarios. Vegetation Recovery suits most west and south areas covered by the sandy land or Gobi, while the Grain for Grass Program is only supportable with the western sandy farmland. The results are instructive to promote key ecosystem functions and services related to serious local ecological problems, and deal with the contradictions between ecological conservation and human development in other similar arid and semiarid regions.

The Process of Soil Desiccation under Haloxylon ammodendron Plantations: A Case Study of the Alxa Legue Desert, China.

Haloxylon ammodendron is a desert shrub widely used as a windbreak and for sand fixation, and it has achieved remarkable results in China. However, in desert areas, large-scale afforestation increases soil water consumption and forms a dried soil layer (DSL), the development of which seriously threatens the sustainable development of the ecosystem. In this study, soil moisture in the 0–400 cm soil profile was measured in selected 5-, 11-, 22-, 34-, and 46-year-old plantations of Haloxylon ammodendron plantations in Alxa Legue, China, and three soil desiccation evaluation indices were calculated—the soil desiccation index (SDI), DSL thickness (DSLT), and DSL soil water content (DSL-SWC)—to analyze the change pattern of the soil water content for different stand ages. The results showed that the shallow water layer (0–200 cm) was depleted sharply in the first five years of Haloxylon ammodendron plantation growth, but no DSL developed; the inflection point of soil water content change appeared after 10 years of growth, after which the shallow soil water was depleted and the drying process of the deep soil water content was significantly faster than that in the early growth period. The deep soil layer (200–400 cm) was depleted seriously after 22 years of afforestation, the soil drying phenomenon was obvious, and the DSL developed from the 172 cm soil layer. After 46 years of afforestation, the DSL was fully developed and the DSL-SWC was only 0.034 cm3 cm−3. Priority should thus be given to the use of less water-consuming shrub species; alternatively, after 5 years of growth of Haloxylon ammodendron plantations, certain water control measures should be taken to maintain the soil water balance.

Transcriptome profiling reveals that foliar water uptake occurs with C3 and crassulacean acid metabolism facultative photosynthesis in Tamarix ramosissima under extreme drought.

Tamarix ramosissima is a typical desert plant species that is widely distributed in the desert areas of Northwest China. It plays a significant role in sand fixation and soil water conservation. In particular, how it uses water to survive in the desert plays an important role in plant growth and ecosystem function. Previous studies have revealed that T. ramosissima can alleviate drought by absorbing water from its leaves under extreme drought conditions. To date, there is no clear molecular regulation mechanism to explain foliar water uptake (FWU). In the present study, we correlated diurnal meteorological data, sap flow and photosynthetic parameters to determine the physical and biological characteristics of FWU. Our results suggested that the lesser the groundwater, the easier it is for T. ramosissima to absorb water via the leaves. Gene ontology annotation and Kyoto Encyclopaedia of Genes and Genomes pathway analysis of the transcriptome profile of plants subjected to high humidity suggested that FWU was highly correlated to carbohydrate metabolism, energy transfer, pyruvate metabolism, hormone signal transduction and plant–pathogen interaction. Interestingly, as a C3 plant, genes such as PEPC, PPDK, MDH and RuBP, which are involved in crassulacean acid metabolism (CAM) photosynthesis, were highly upregulated and accompanied by FWU. Therefore, we proposed that in the case of sufficient water supply, C3 photosynthesis is used in T. ramosissima, whereas in cases of extreme drought, starch is degraded to provide CO2 for CAM photosynthesis to make full use of the water obtained via FWU and the water that was transported or stored to assimilating branches and stems. This study may provide not only an important theoretical foundation for FWU and conversion from C3 plants to CAM plants but also for engineering improved photosynthesis in high-yield drought-tolerant plants and mitigation of climate change-driven drought.

Identifying the flow paths and beneficiary ranges of the sand fixation service: A case‐study in Xilingol League, China

AbstractThe sand fixation service (SFS) is a function of vegetation ecosystems whereby sand is restrained and stabilized. It not only generates ecological benefits for local areas but also affects circulation media such as wind and has an impact on surrounding areas. Therefore, it is urgent to study the flow process and influence of the SFS, so as to provide a theoretical basis for cross‐regional ecological compensation. We chose Xilingol League (shorten as "Xilingol") as the study area and used the hybrid single‐particle Lagrangian integrated trajectory (HYSPLIT) model to comprehensively identify the spatial flow paths (FPs) and beneficiary ranges (BRs) of the SFS from 2000 to 2018. The results showed that there were 726 FPs of the SFS, which were mainly distributed in spring, accounting for 63.50% of the total FPs. The total area of the BRs was 279.50 × 104 km2, accounting for 29.15% of China's land area. The high‐frequency BRs were mainly distributed in the southeast of Inner Mongolia, northern Hebei, northern Liaoning, northern Beijing, and northwestern Jilin. In terms of BRs, farmland was the largest (92.09 × 104 km2) land cover type, accounting for 34.51% of the total area of the BRs, and the total beneficiary population and gross domestic product accounting for 44.53% and 50.06% of whole China in 2015. Identification of FPs and BRs of SFS in this study could provide a reference to make ecology compensation policy at national level.

Quantitative Assessment for the Spatiotemporal Changes of Ecosystem Services, Tradeoff–Synergy Relationships and Drivers in the Semi-Arid Regions of China

Ecosystem services in arid inland regions are significantly affected by climate change and land use/land cover change associated with agricultural activity. However, the dynamics and relationships of ecosystem services affected by natural and anthropogenic drivers in inland regions are still less understood. In this study, the spatiotemporal patterns of ecosystem services in the Hexi Region were quantified based on multiple high-resolution datasets, the InVEST model and the Revised Wind Erosion Equation (RWEQ) model. In addition, the trade-offs and synergistic relationships among multiple ecosystem services were also explored by Pearson correlation analysis and bivariate spatial autocorrelation, and redundancy analysis (RDA) was also employed to determine the environmental drivers of these services and interactions. The results showed that most ecosystem services had a similar spatial distribution pattern with an increasing trend from northwest to southeast. Over the past 40 years, ecosystem services in the Hexi Region have improved significantly, with the water retention and soil retention increasing by 87.17 × 108 m3 and 287.84 × 108 t, respectively, and the sand fixation decreasing by 369.17 × 104 t. Among these ecosystem services, strong synergistic relationships were detected, while the trade-offs were found to be weak, and showed significant spatial heterogeneity in the Hexi Region. The spatial synergies and trade-offs in the Qilian Mountains were 1.02 and 1.37 times higher than those in the Hexi Corridor, respectively. Human activities were found to exacerbate the trade-offs between ecosystem services by increasing water consumption in the Hexi Corridor, with the exception of carbon storage. In particular, there were significant tradeoffs between food production and water retention, and between soil retention and habitat quality in the oases of the Hexi Corridor, which is affected by rapid population growth and cropland expansion. Additionally, precipitation, temperature and vegetation cover in the Qilian Mountains have increased significantly over the past four decades, and these increases significantly contributed to the enhancements in water retention, carbon storage, habitat quality, soil retention and food production. Nevertheless, the amount of sand fixation significantly decreased, and this was probably associated with the reduction in wind speed over the past four decades. Our results highlighted the importance of climate wetting and water resource management in the enhancement of ecosystem services and the mitigation of food production trade-offs for arid inland regions.