Subjects: Biology >> Ecology submitted time 2024-04-15 Cooperative journals: 《干旱区科学》
Abstract： Land use change affects the balance of organic carbon (C) reserves and the global C cycle. Microbial residues are essential constituents of stable soil organic C (SOC). However, it remains unclear how microbial residue changes over time following afforestation. In this study, 16-, 23-, 52-, and 62-year-old Mongolian pine stands and 16-year-old cropland were studied in the Horqin Sandy Land, China. We analyzed changes in SOC, amino sugar content, and microbial parameters to assess how microbial communities influence soil C transformation and preservation. The results showed that SOC storage increased with stand age in the early stage of afforestation but remained unchanged at about 1.27−1.29 kg/m2 after 52 a. Moreover, there were consistent increases in amino sugars and microbial residues with increasing stand age. As stand age increased from 16 to 62 a, soil pH decreased from 6.84 to 5.71, and the concentration of total amino sugars increased from 178.53 to 509.99 mg/kg. A significant negative correlation between soil pH and the concentration of specific and total amino sugars was observed, indicating that the effects of soil acidification promote amino sugar stabilization during afforestation. In contrast to the Mongolian pine plantation of the same age, the cropland accumulated more SOC and microbial residues because of fertilizer application. Across Mongolian pine plantation with different ages, there was no significant change in calculated contribution of bacterial or fungal residues to SOC, suggesting that fungi were consistently the dominant contributors to SOC with increasing time. Our results indicate that afforestation in the Horqin Sandy Land promotes efficient microbial growth and residue accumulation in SOC stocks and has a consistent positive impact on SOC persistence.
Subjects: Biology >> Ecology submitted time 2024-03-13 Cooperative journals: 《干旱区科学》
Abstract： Nitrogen (N) deposition is a significant aspect of global change and poses a threat to terrestrial biodiversity. The impact of plant-soil microbe relationships to N deposition has recently attracted considerable attention. Soil microorganisms have been proven to provide nutrients for specific plant growth, especially in nutrient-poor desert steppe ecosystems. However, the effects of N deposition on plant-soil microbial community interactions in such ecosystems remain poorly understood. To investigate these effects, we conducted a 6-year N-addition field experiment in a Stipa breviflora Griseb. desert steppe in Inner Mongolia Autonomous Region, China. Four N treatment levels (N0, N30, N50, and N100, corresponding to 0, 30, 50, and 100 kg N/(hm2•a), respectively) were applied to simulate atmospheric N deposition. The results showed that N deposition did not significantly affect the aboveground biomass of desert steppe plants. N deposition did not significantly reduce the alfa-diversity of plant and microbial communities in the desert steppe, and low and mediate N additions (N30 and N50) had a promoting effect on them. The variation pattern of plant Shannon index was consistent with that of the soil bacterial Chao1 index. N deposition significantly affected the beta-diversity of plants and soil bacteria, but did not significantly affect fungal communities. In conclusion, N deposition led to co-evolution between desert steppe plants and soil bacterial communities, while fungal communities exhibited strong stability and did not undergo significant changes. These findings help clarify atmospheric N deposition effects on the ecological health and function of the desert steppe.
Subjects: Biology >> Ecology submitted time 2024-01-23
Abstract： In the meta-barcoding based eDNA monitoring technology, the analysis and annotation of eDNA sequencing data serve as the foundation for obtaining accurate and reliable monitoring results. The selection of reference databases, the determination of analysis & annotation indicator thresholds, and the preparation of target data are the most critical technical steps in eDNA sequencing data analysis and annotation. To clarify the impacts of these three technical aspects and provide scientific support for the standardization of eDNA monitoring technology, the current study used two sets of COI gene sequence data from eDNA monitoring in the middle reach of the Yangtze River as the analysis objects and designed three sets of experiments to test 1) the impacts of different reference databases and species annotation algorithms on the annotation results, 2) the impacts of different OTU clustering sequence similarity and species annotation classification confidence (sequence consistency and sequence coverage) on the annotation results, and 3) the impacts of different target sequence data richness of each species on the annotation results. The results showed that: 1) under the Blast algorithm, the annotated species matched with three versions of nt library from NCBI were generally consistent (72%~78%); those matched with two local sequence reference libraries were also generally consistent (91%~96%); and the annotated species from the five result matched with these five sequence reference libraries were consistent in 52%~68%. The RDP Classifier algorithm annotated species matched with nt libraries covered over 95% of Blast algorithm annotated species, and increased by 151%~443% species, but most additional species were misannotated. The RDP Classifier algorithm annotated species matched with local sequence reference libraries covered 66%~85% of Blast algorithm annotated species, and there were several results only annotated to family or genus level. 2) When the OTU clustering sequence similarity threshold was set to 0.999, it obtained 154%~209% more OTUs than when set to 0.99, and 240%~490% more annotated OTUs of fish were obtained. The classification confidence threshold (Blast algorithm) had little effect on species composition when changed from 0.8 to 0.99, with over 94% consistency, but there was a significant difference when it was set to 0.7. 3) When the OTU clustering sequence similarity threshold was 0.999 and the classification confidence threshold was 0.9, the number of fish species and OTUs obtained from multiple sequences data annotation was the largest, and had the highest species annotation accuracy (81.49%), which increased by 7% fish species, 215% OTUs and 5% accuracy respectively compared to single sequences data annotation. In eDNA sequencing data analysis and annotation, accuracy can be improved by establishing and improving local reference databases, optimizing OTU clustering sequence similarity and species annotation classification confidence thresholds (sequence consistency and sequence coverage), increasing target sequence data richness. However, due to the limitation of species annotation algorithms, problems such as species annotation errors and omissions may persist in eDNA sequencing data analysis and annotation in the future. Then, the species annotation accuracy of eDNA monitoring (based on the COI gene) would always lower than 85%.
Peer Review Status:
Awaiting Review
Subjects: Biology >> Ecology submitted time 2024-01-12 Cooperative journals: 《干旱区科学》
Abstract： Studying the spatiotemporal variations in ecosystem services and their interrelationships on the Loess Plateau against the background of the gully control and land consolidation (GCLC) project has significant implications for ecological protection and quality development of the Yellow River Basin. Therefore, in this study, we took Yan'an City, Shaanxi Province of China, as the study area, selected four typical ecosystem services, including soil conservation service, water yield service, carbon storage service, and habitat quality service, and quantitatively evaluated the spatiotemporal variation characteristics and trade-offs and synergies of ecosystem services from 2010 to 2018 using the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model. We also analysed the relationship between the GCLC project and regional ecosystem service changes in various regions (including 1 city, 2 districts, and 10 counties) of Yan'an City and proposed a coordinated development strategy between the GCLC project and the ecological environment. The results showed that, from 2010 to 2018, soil conservation service decreased by 7.76%, while the other three ecosystem services changed relatively little, with water yield service increasing by 0.56% and carbon storage service and habitat quality service decreasing by 0.16% and 0.14%, respectively. The ecological environment of Yan'an City developed in a balanced way between 2010 and 2018, and the four ecosystem services showed synergistic relationships, among which the synergistic relationships between soil conservation service and water yield service and between carbon storage service and habitat quality service were significant. The GCLC project had a negative impact on the ecosystem services of Yan'an City, and the impact on carbon storage service was more significant. This study provides a theoretical basis for the scientific evaluation of the ecological benefits of the GCLC project and the realization of a win-win situation between food security and ecological security.
Subjects: Biology >> Ecology submitted time 2024-01-12 Cooperative journals: 《干旱区科学》
Abstract： Regional sustainable development necessitates a holistic understanding of spatiotemporal variations in ecosystem carbon storage (ECS), particularly in ecologically sensitive areas with arid and semi-arid climate. In this study, we calculated the ECS in the Ningxia Section of Yellow River Basin, China from 1985 to 2020 using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model based on land use data. We further predicted the spatial distribution of ECS in 2050 under four land use scenarios: natural development scenario (NDS), ecological protection scenario (EPS), cultivated land protection scenario (CPS), and urban development scenario (UDS) using the patch-generating land use simulation (PLUS) model, and quantified the influences of natural and human factors on the spatial differentiation of ECS using the geographical detector (Geodetector). Results showed that the total ECS of the study area initially increased from 1985 until reaching a peak at 402.36×106 t in 2010, followed by a decreasing trend to 2050. The spatial distribution of ECS was characterized by high values in the eastern and southern parts of the study area, and low values in the western and northern parts. Between 1985 and 2020, land use changes occurred mainly through the expansion of cultivated land, woodland, and construction land at the expense of unused land. The total ECS in 2050 under different land use scenarios (ranked as EPS>CPS>NDS>UDS) would be lower than that in 2020. Nighttime light was the largest contributor to the spatial differentiation of ECS, with soil type and annual mean temperature being the major natural driving factors. Findings of this study could provide guidance on the ecological construction and high-quality development in arid and semi-arid areas.
Subjects: Biology >> Ecology submitted time 2024-01-12 Cooperative journals: 《干旱区科学》
Abstract： Gross primary productivity (GPP) of vegetation is an important constituent of the terrestrial carbon sinks and is significantly influenced by drought. Understanding the impact of droughts on different types of vegetation GPP provides insight into the spatiotemporal variation of terrestrial carbon sinks, aiding efforts to mitigate the detrimental effects of climate change. In this study, we utilized the precipitation and temperature data from the Climatic Research Unit, the standardized precipitation evapotranspiration index (SPEI), the standardized precipitation index (SPI), and the simulated vegetation GPP using the eddy covariance-light use efficiency (EC-LUE) model to analyze the spatiotemporal change of GPP and its response to different drought indices in the Mongolian Plateau during 1982–2018. The main findings indicated that vegetation GPP decreased in 50.53% of the plateau, mainly in its northern and northeastern parts, while it increased in the remaining 49.47% area. Specifically, meadow steppe (78.92%) and deciduous forest (79.46%) witnessed a significant decrease in vegetation GPP, while alpine steppe (75.08%), cropland (76.27%), and sandy vegetation (87.88%) recovered well. Warming aridification areas accounted for 71.39% of the affected areas, while 28.53% of the areas underwent severe aridification, mainly located in the south and central regions. Notably, the warming aridification areas of desert steppe (92.68%) and sandy vegetation (90.24%) were significant. Climate warming was found to amplify the sensitivity of coniferous forest, deciduous forest, meadow steppe, and alpine steppe GPP to drought. Additionally, the drought sensitivity of vegetation GPP in the Mongolian Plateau gradually decreased as altitude increased. The cumulative effect of drought on vegetation GPP persisted for 3.00–8.00 months. The findings of this study will improve the understanding of how drought influences vegetation in arid and semi-arid areas.
Subjects: Biology >> Ecology submitted time 2023-12-20 Cooperative journals: 《干旱区科学》
Abstract： Reclamation of lands abandoned after mining in mountain areas is critical to erosion control, safety from landslides, and ecological protection of mountain ecosystems. However, little is known about alpine coal mine reclamation using the soil seed bank as a potential source for revegetation. We collected samples of persistent soil seed bank for germination experiments from nine reclaimed sites with different soil cover thicknesses and from six control sites in the Qilian Mountains of China. Soil properties of each site were determined (including soil water content, soil available potassium, soil available phosphorus, soil total nitrogen, pH, soil organic matter, soil total phosphorus, and soil total potassium, and soil alkali-hydrolyzable nitrogen), and the relationships of the characteristics of the soil seed bank with soil cover thickness and soil properties were examined. The results showed that the density, number of species, and diversity of the topsoil seed bank were significantly correlated with soil cover thickness, and all increased with the increment of soil cover thickness. Soil cover thickness controlled the soil seed bank by influencing soil properties. With the increase in soil cover thickness, soil properties (e.g., soil organic matter, soil total nitrogen, etc.) content increased while soil pH decreased. The soil seed bank had the potential to restored the pre-mining habitat at reclaimed sites with approximately 20-cm soil cover thickness. Soil properties of reclaimed sites were lower than that of natural sites. The relationship between the soil seed bank and soil cover thickness determined in this study provides a foundation for improving reclamation measures used in coal mines, as well as for the management and monitoring of reclaimed areas.
Subjects: Biology >> Ecology submitted time 2023-12-20 Cooperative journals: 《干旱区科学》
Abstract： Grassland degradation can alter the structure and function of ecosystem and soil seed bank. Therefore, estimating the role of soil seed bank in vegetation regeneration of degraded grasslands is crucial. We selected grasslands with three levels of degradation, namely non-degraded (ND), mildly degraded (MD), and heavily degraded (HD) to analyze the effect of grassland degradation on soil seed bank, as well as the role of soil seed bank on vegetation regeneration of the alpine grasslands, China. Soil samples from each level were collected in May, before seedling emergence, in August, after completion of transient seed bank germination, and in December, after seed dispersal, to determine the seed density and species composition through germination experiment. Result showed that a total of 35 plant species was identified, including 15 species observed in both soil seed bank and above-ground vegetation. A total of 19, 15, and 14 species of soil seed bank were identified in December, May, and August, respectively. The most abundant species in soil seed bank were Compositae (5 species), followed by Poaceae (4 species), and Cyperaceae (3 species). Degradation level has no significant impact on species richness and Shannon- Wiener index of soil seed bank. In addition, sampling month and grassland degradation affected soil seed bank density, in which December>May>August, and ND>MD>HD, indicating that density of transient seed bank was greater than persistent seed bank. Soil seed bank density of surface layer (0–5 cm) accounting for 42%–72% of the total density, which was significantly higher than that of deep layer (5–10 cm). Similarity of species composition between vegetation and soil seed bank was low, and it increased with degradation level (ranged from 0.14 to 0.69). We concluded that grassland degradation affects soil seed bank density more than species diversity, and soil seed bank contributed slightly to vegetation regeneration of degraded alpine grassland. Therefore, it is unlikely that degraded alpine meadow can be restored solely through soil seed bank.
Subjects: Biology >> Ecology submitted time 2023-11-13 Cooperative journals: 《干旱区科学》
Abstract： Mangrove forests are valuable resources in tropical and subtropical regions, which have been faced dieback due to various human activities including rapid expansion of shrimp farming, urban development, and pollution, as well as natural factors such as rising sea level, increasing air temperature, drought, and sharp decrease in rainfall. However, the mechanisms of dieback of mangrove forests are not well understood. Therefore, this research aimed to assess the vegetative, chemical, and physiological status of grey mangrove (Avicennia marina (Forsk.) Vierh.) forests at different intensities of dieback in the Hormozgan Province, Iran. A total of 40 plots categorized into four dieback intensities (severe, medium, low, and control) were randomly selected for monitoring, and various parameters related to vegetative, chemical, and physiological status of grey mangrove forests were examined. The results revealed that the control group had the highest tree density, seedling density, vitality levels, aerial root density, and aerial root height. Generally, as dieback severity increased, a decrease in demographic and vegetative parameters of trees and seedlings was observed in the dieback treatments. The amounts of heavy metals (lead, cadmium, and nickel) in the sediment, roots, and leaves of grey mangrove trees at different dieback levels indicated that lead levels were the highest in the sediment, roots, and leaves in the severe dieback treatment. At the same time, the control had the lowest values. Cadmium concentrations in the sediment followed the pattern of severe dieback>moderate dieback>low dieback>control with no significant differences in the roots and leaves. Nickel amounts in all three parts, i.e., sediment, roots, and leaves showed the highest levels in the severe dieback treatment. Furthermore, metal level analysis in the organs of grey mangrove trees at different dieback levels revealed that lead and nickel were more abundant in the root organ compared with the leaves. In contrast, the leaf organ exhibited the highest cadmium levels. Dieback significantly impacted water electrical conductivity (EC), soil organic carbon (SOC), and chlorophyll a, b, and total chlorophyll contents, with the highest values observed in the severe dieback treatment. However, no significant differences were observed in acidity and carotenoid levels. In conclusion, sediment erosion and heavy metal accumulation were critical contributors to dieback of grey mangrove trees, affecting their physiological, vegetative, and plant production characteristics. As the ability of these plants to rehabilitate has diminished, effective management planning is imperative in dieback-affected areas.
Subjects: Biology >> Ecology submitted time 2023-11-13 Cooperative journals: 《干旱区科学》
Abstract： The plantation of non-native species is one of the most expensive ecological restoration measures in arid and semi-arid areas, while its impacts on local communities are largely ignored. This study assessed the rate of change and the dynamic degree of the economic values of ecosystem services related to local conservation (water yield, stocking rate and aesthetic value) and preserving the future (carbon sequestration, soil protection, soil stability and habitat provision) to determine the restoration success of the plantation of non-native species Haloxylon ammodendron (C.A.Mey.) Bunge ex Fenzl (15- and 30-year-old) in parts of arid rangelands of Bardsir region, Kerman Province, Iran. We investigated the impacts of the two plantations on the seven ecosystem services and ecosystem structures (horizontal and vertical structures, vegetation composition and species diversity) based on field sampling and measurements at four sampling sites (i.e., control, degraded, and 15- and 30-year-old plantation sites) in spring and summer of 2022. The restoration success of the plantation of non-native species was then examined by assessing the rate of change and the dynamic degree of the total economic value of all ecosystem services as well as the rate of change and the dynamic degree of the economic values of ecosystem services for the two groups (local conservation and preserving the future). Although the plantation of non-native species H. ammodendron enormously improved the vertical and horizontal structures of ecosystems, it failed to increase species diversity and richness fully. Further, despite the plantation of non-native species H. ammodendron had significantly increased the economic values of all ecosystem services, it was only quite successful in restoring carbon sequestration. Path analysis showed that plantation age had a significant impact on restoration success directly and indirectly (through changing ecosystem structures and services). The dynamic degree of the economic values of ecosystem services related to local conservation and preserving the future at the 15- and 30-year-old plantation sites indicated that the two plantations successfully restored the ecosystem services related to preserving the future. The presented method can help managers select the best restoration practices and predict their ecological-social success, especially for the plantation of high-risk non-native species in arid and semi-arid areas.
Subjects: Biology >> Ecology submitted time 2023-10-17 Cooperative journals: 《干旱区科学》
Abstract：In the Anthropocene era, human activities have become increasingly complex and diversified. The natural ecosystems need higher ecological resilience to ensure regional sustainable development due to rapid urbanization and industrialization as well as other intensified human activities, especially in arid and semi-arid areas. In the study, we chose the economic belt on the northern slope of the Tianshan Mountains (EBNSTM) in Xinjiang Uygur Autonomous Region of China as a case study. By collecting geographic data and statistical data from 2010 and 2020, we constructed an ecological resilience assessment model based on the ecosystem habitat quality (EHQ), ecosystem landscape stability (ELS), and ecosystem service value (ESV). Further, we analyzed the temporal and spatial variation characteristics of ecological resilience in the EBNSTM from 2010 to 2020 by spatial autocorrelation analysis, and explored its responses to climate change and human activities using the geographically weighted regression (GWR) model. The results showed that the ecological resilience of the EBNSTM was at a low level and increased from 0.2732 to 0.2773 during 20102020. The spatial autocorrelation analysis of ecological resilience exhibited a spatial heterogeneity characteristic of high in the western region and low in the eastern region, and the spatial clustering trend was enhanced during the study period. Desert, Gobi and rapidly urbanized areas showed low level of ecological resilience, and oasis and mountain areas exhibited high level of ecological resilience. Climate factors had an important impact on ecological resilience. Specifically, average annual temperature and annual precipitation were the key climate factors that improved ecological resilience, while average annual evapotranspiration was the main factor that blocked ecological resilience. Among the human activity factors, the distance from the main road showed a negative correlation with ecological resilience. Both night light index and PM2.5 concentration were negatively correlated with ecological resilience in the areas with better ecological conditions, whereas in the areas with poorer ecological conditions, the correlations were positive. The research findings could provide a scientific reference for protecting the ecological environment and promoting the harmony and stability of the human-land relationship in arid and semi-arid areas.
Subjects: Biology >> Ecology submitted time 2023-10-17 Cooperative journals: 《干旱区科学》
Abstract：Changes in precipitation and nitrogen (N) addition may significantly affect the processes of soil carbon (C) cycle in terrestrial ecosystems, such as soil respiration. However, relatively few studies have investigated the effects of changes in precipitation and N addition on soil respiration in the upper soil layer in desert steppes. In this study, we conducted a control experiment that involved a field simulation from July 2020 to December 2021 in a desert steppe in Yanchi County, China. Specifically, we measured soil parameters including soil temperature, soil moisture, total nitrogen (TN), soil organic carbon (SOC), soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN), and contents of soil microorganisms including bacteria, fungi, actinomyces, and protozoa, and determined the components of soil respiration including soil respiration with litter (RS+L), soil respiration without litter (RS), and litter respiration (RL) under short-term changes in precipitation (control, increased precipitation by 30%, and decreased precipitation by 30%) and N addition (0.0 and 10.0 g/(m2a)) treatments. Our results indicated that short-term changes in precipitation and N addition had substantial positive effects on the contents of TN, SOC, and SMBC, as well as the contents of soil actinomyces and protozoa. In addition, N addition significantly enhanced the rates of RS+L and RS by 4.8% and 8.0% (P0.05). The mean RL/RS+L value observed under all treatments was 27.63%, which suggested that RL is an important component of soil respiration in the desert steppe ecosystems. The results also showed that short-term changes in precipitation and N addition had significant interactive effects on the rates of RS+L, RS, and RL (P
Subjects: Geosciences >> Geography Subjects: Biology >> Ecology Subjects: Law >> Civil and Commercial Law Subjects: Management Science >> Business Management of Department Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-10-06
Abstract： Purpose/significance South Africa is a world famous "tourist paradise". A thematic study on how South Africa is developing its tourism industry can provide a useful reference for China. Method/process This paper summarizes South Africa's experience in tourism development, based mainly on foreign research data and using literature review methods. Result/conclusion In the development of tourism, South Africa has five major successful experiences: first, it has attached great importance to tourism and taken a number of initiatives, including the enactment of the Tourism Act, the introduction of a number of tourism development strategies and plans, and the establishment of the Department of Tourism of South Africa and the South African Tourism; second, it has actively upgraded its hardware and software facilities; third, it has endeavored to diversify its tourism products; fourth, it has put the concept of responsible tourism into practice; and fifth, it has made great efforts to develop its domestic tourism industry.
Peer Review Status:Awaiting Review
Subjects: Biology >> Ecology submitted time 2023-08-26 Cooperative journals: 《干旱区研究》
Abstract： The Shanshan Kumtag Desert, which is connected to the city, contains rich and unique microbialresources. To explore the microbial community structure and its relationship with environmental factors in theShanshan Kumtag Desert, surface (0-5 cm) and deep (45-50 cm) layer sand samples were collected from fourpoints along the northern margin of the desert. Subsequently, the collected samples were analyzed to determinethe water content (WC), pH, total carbon (TC), total nitrogen (TN), total organic carbon (TOC), and electricalconductivity. High-throughput sequencing technology was used to analyze the bacterial community structure ofthe sand samples, and Spearman correlation was used to analyze the correlation between environmental factorsand the bacterial community structure. The results showed that the collected sand samples were alkaline, and thedominant bacterial phyla were Actinobacteria, Firmicutes, Proteobacteria, and Bacteroidetes. Among these, thedominant genera were unclassified_f__Micrococcaceae, Bacillus, Sphingomonas, Escherichia- Shigella, andMicrobacterium. Significant differences in the bacterial community structure were observed among the differentpoints along the northern margin of the Shanshan Kumtag Desert (P < 0.05). However, no significant differencein species diversity was observed between the surface and deep layer samples. Furthermore, WC, TC, TN, andpH significantly affected the bacterial community structure in the surface samples (P < 0.05), while TOCsignificantly affected the bacterial community structure in the deep samples (P < 0.05). This study provides atheoretical basis for exploring microbial resources in the Shanshan Kumtag Desert and similar habitats.
Subjects: Biology >> Ecology submitted time 2023-08-26 Cooperative journals: 《干旱区研究》
Abstract： To investigate the response of plant community distribution to topography and soil factors in the premountaindesert grassland of Baicheng County on the southern piedmont of Tianshan Mountain, we selected atypical area for investigation. We used the dominance method and canonical correspondence analysis (CCA) tostudy the relationship between plant community distribution and topography and soil factors in the mountaindesert grassland. We observed differences in the species diversity of shrub and herb layers between survey samplesites. Specifically, the Shannon-Wiener index, Pielou index, and Simpson index on the eastern slope showed moreshrubs than herbs; while on the western and northern slopes, these indexes showed more herbs than shrubs. Theresults of CCA show that topographic factors influenced plant community diversity in the order of slopeorientation > slope gradient > slope position; and soil factors influenced plant community diversity in the order ofsoil moisture in the 30-100 cm soil layer > total soil porosity (STP) > soil moisture in the 0-30 cm soil layer(SMC-1). Topography and soil factors had certain screening effects on the formation of plant communities. Soilmoisture in the 30-100 cm soil layer and slope orientation were the key factors affecting the distribution of plantcommunities in the pre- mountain desert grassland of Baicheng County on the southern piedmont of TianshanMountain.
Subjects: Biology >> Ecology submitted time 2023-08-26 Cooperative journals: 《干旱区研究》
Abstract： Carbon sequestration is among the main functions of terrestrial ecosystem services, and the carbonsequestration capacity of terrestrial ecosystems directly affects global carbon emissions and climate changeprocesses. Human activities directly influence land use and cover change, consequently affecting the carbonsequestration function of ecosystems. The terrestrial ecosystem services in dry and cold regions are morevulnerable and significantly impacted by human activities. Therefore, utilizing land use data from the Irtysh RiverBasin in the Altai Mountains from 2000 to 2020, the InVEST model was used to estimate and analyze the spatialdistribution of carbon stocks in the basin during different periods. Subsequently, the influence of human activitieson the spatial distribution of carbon stocks was discussed. The results show the following: (1) The main land usetypes in the basin are woodland, grassland, and unused land, and the land use pattern changed significantly from2000 to 2020. Cultivated land, urban and rural land, industrial and mining land, and residential land expandedcontinuously, increasing by 2619.35 km2 and 186.68 km2, respectively. Grassland and water areas initiallydecreased and then expanded, increasing by 4725.13 km2 and 33.47 km2, respectively. Meanwhile, forest land andunused land decreased continuously by 2328.88 km2 and 5237.76 km2, respectively. (2) During this period, thespatial distribution pattern of carbon stocks in the basin was similar and showed a zonal distribution. High-valueareas were distributed in high- altitude regions where grassland and woodland were clustered, while low- valueareas were distributed in low-altitude regions where unused land was clustered. In 2000, 2005, 2010, 2015, 2020the total carbon storage in the basin was 641.60 Tg, 645.78 Tg, 646.83 Tg, 650.28 Tg, and 665.91 Tg,respectively , with an annual growth rate of 0.95%, showing an upward trend. (3) The areas in the basin wherecarbon storage decreased or increased showed a spot- like distribution. Furthermore, carbon storage reductionmainly occurred through the conversion of grassland to unused land and cultivated land, with an average annualreduction of 58.81 Tg. The increase in carbon storage primarily resulted from the conversion of unused land intocultivated land and grassland, with an average annual increase of 64.82 Tg. From 2000 to 2020, the netsequestration of carbon storage exceeded the net release, indicating an increasing carbon sequestration capacity inthe Irtysh River Basin. Overall, the reclamation of land and grass due to human activities is the main reason forthe increase in carbon storage in the basin. However, it is necessary to coordinate the development and utilizationof water and soil resources, as this will guarantee not only an increased carbon sink but also the preservation ofthe carrying capacity of water and soil resources, ultimately achieving sustainable economic development in theIrtysh River Basin. The results of this study will help to promote the carbon cycle of the basin and the carbonsequestration capacity of the ecosystem, as well as provide a scientific basis for the establishment andmanagement of the basin carbon pool.
Subjects: Biology >> Ecology submitted time 2023-08-26 Cooperative journals: 《干旱区研究》
Abstract： Sand bound land protection area (sand bound area) is an important means to prevent desertification,restore vegetation, maintain ecological security, and promote sustainable economic and social development ofcontiguous sand bound land that does not have control and development. As primary body of the operations insand bound area, farmers’construction has an impact on their livelihood. To explore the impact of livelihoodcapital on livelihood strategy selection in this region. This paper adopts the participatory rural assessment method(PRA) and takes Linze County of Zhangye City as an example. Based the sustainable livelihoods approach (SLA)sustainable analysis framework paired with binary logistic regression model. The results show that (1) Naturaland human capital significantly affect the choice of pure agricultural livelihood strategy. Material and socialcapital have significant influence on the choice and agriculture livelihood strategy. Financial capital is the mainfactor of non-agricultural livelihood strategy selection (2) The reserves livelihood capital affect farmers’choiceof different types of livelihood strategies, and the more reserves, the stronger the sensitivity of choice. (3) Thewillingness of different types of farmers to adjust the existing livelihood strategy is very different, 68% of purefarmers and 56% of part- time farmers hope to adjust the existing livelihood strategy; 63% of non- farmers areunwilling to adjust their existing livelihood strategies. The conclusion provides a theoretical basis for improvingthe livelihood and ecological security of local farmers and promoting the sustainable development of socialeconomy.
Subjects: Biology >> Ecology submitted time 2023-08-26 Cooperative journals: 《干旱区研究》
Abstract： The dry Tarim River Basin in Northwest China acts as a crucial ecotone for Xinjiang’s agricultural andgrazing resources. Therefore, studying agricultural nonpoint source pollution is essential for the green andsustainable growth of basin agriculture. This research offers a gray water footprint theory-based assessment indexfor China’s sustainable development. Furthermore, the Tarim River Basin’s regional and temporal variationpatterns are examined using SDGs framework. The agricultural gray water footprint’s intensity and efficienciesare estimated for 2006-2020. The findings are shown as below. (1) The Tarim River Basin’s entire agriculturalgray water footprint has reduced, falling from 6.95 × 1010 m3 in 2006 (highest value) to 3.96 × 1010 m3 in 2017(lowest value). The main source of the gray water footprint is animal husbandry. (2) In the Tarim River Basin, theintensity of the agricultural gray water footprint has decreased by 62.5% from 4.48×104 m3·hm-2 in 2006 to 1.68×104 m3·hm-2 in 2017. (3) The Tarim River Basin’s agricultural gray water footprint efficiency has increased from0.6 yuan·m-3 in 2006 to 4.03 yuan·m-3 in 2019. To sum up, initiatives to improve the water environment in theTarim River Basin should emphasize encouraging the integrated development of agriculture and animalhusbandry in agricultural areas, modifying the livestock and poultry breeding structure and putting livestock andpoultry manure recycling into practice.
Subjects: Biology >> Ecology submitted time 2023-08-25 Cooperative journals: 《干旱区研究》
Abstract： The soil properties and moss crust development indices in typical Artemisia ordosica and Salixpasmmophia shrub land plots in the sandy area of Mu Us Sandland have previously been analyzed in combinationwith allelopathic tests of the extracts from the different shrub organs. The results showed that moss crust developmentin A. ordosica shrub land was better than that in S. pasmmophia shrub land, but the reason is unclear, andelucidating it is the aim of this investigation. A significant difference in the moss crust coverage between the twokinds of shrubs (P < 0.05) was identified. The total moss crust coverage and sub-canopy and inter-canopy crustcoverage were as follows: A. ordosica > S. pasmmophia, and the total moss crust coverage and subcanopy and intercanopycrust coverage in the A. ordosica shrub land were 1.6, 2.9, and 1.1 times higher than those in the sandS. pasmmophia shrub land, respectively. Furthermore, there was no significant difference in moss crust thicknessbetween the two kinds of shrubs (P > 0.05). Pearson correlation analysis showed that the moss crust coverage inthe sub-canopy was significantly positively correlated with the soil water content, moss crust thickness in the subcanopywas significantly positively correlated with silt content, and inter-canopy moss crust coverage was significantlypositively correlated with soil water and clay content (P < 0.05). The higher soil water, clay, and silt contentsin the A. ordosica shrub land promoted the development of moss crusts. The aqueous extracts from the roots,stems, and leaves of the A. ordosica and S. pasmmophia inhibited the development of moss crusts; that is, the allelopathicsynthesis effect (SE) was negative. Specifically, the allelopathic inhibitory effect of the 0.2 g·mL-1 aqueousextract of the S. pasmmophia leaves was the strongest, with an SE of −0.95. The inhibitory effect was significantlyhigher than that of the A. ordosica leaves (SE = −0.65). It can be inferred from the results that the highersoil water, clay, and silt contents in the A. ordosica shrub land and the significant allelopathic inhibition of the S.pasmmophia leaves on the moss crusts led to the improved development of moss crusts in A. ordosica shrub landwhen compared with S. pasmmophia shrub land.
Subjects: Biology >> Ecology submitted time 2023-08-15 Cooperative journals: 《干旱区科学》
Abstract：Microorganisms regulate the responses of terrestrial ecosystems to anthropogenic nutrient inputs. The escalation of anthropogenic activities has resulted in a rise in the primary terrestrial constraining elements, namely nitrogen (N) and phosphorus (P). Nevertheless, the specific mechanisms governing the influence of soil microbial community structure and ecological processes in ecologically vulnerable and delicate semi-arid loess agroecosystems remain inadequately understood. Therefore, we explored the effects of different N and P additions on soil microbial community structure and its associated ecological processes in the farmland of Chinese Loess Plateau based on a 36-a long-term experiment. Nine fertilization treatments with complete interactions of high, medium, and low N and P gradients were set up. Soil physical and chemical properties, along with the microbial community structure were measured in this study. Additionally, relevant ecological processes such as microbial biomass, respiration, N mineralization, and enzyme activity were quantified. To elucidate the relationships between these variables, we examined correlation-mediated processes using statistical techniques, including redundancy analysis (RDA) and structural equation modeling (SEM). The results showed that the addition of N alone had a detrimental effect on soil microbial biomass, mineralized N accumulation, and -1,4-glucosidase activity. Conversely, the addition of P exhibited an opposing effect, leading to positive influences on these soil parameters. The interactive addition of N and P significantly changed the microbial community structure, increasing microbial activity (microbial biomass and soil respiration), but decreasing the accumulation of mineralized N. Among them, N24P12 treatment showed the greatest increase in the soil nutrient content and respiration. N12P12 treatment increased the overall enzyme activity and total phospholipid fatty acid (PLFA) content by 70.93%. N and P nutrient contents of the soil dominate the microbial community structure and the corresponding changes in hydrolytic enzymes. Soil microbial biomass, respiration, and overall enzyme activity are driven by mineralized N. Our study provides a theoretical basis for exploring energy conversion processes of soil microbial community and environmental sustainability under long-term N and P additions in semi-arid loess areas.
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