Desertification poses a significant ecological threat to global sustainability,notably within arid regions such as the Tarim Basin surrounding the extensive Taklimakan Desert in Northwest China.This study used the Goo...Desertification poses a significant ecological threat to global sustainability,notably within arid regions such as the Tarim Basin surrounding the extensive Taklimakan Desert in Northwest China.This study used the Google Earth Engine(GEE)platform and Random Forest(RF)to analyze multi-temporal Landsat images to reveal desertification dynamics in the Tarim Basin spanning from 1990 to 2020.The results showed that land use types of the Tarim Basin were classified into three types:artificial oases,natural oases,and desertified land.To robustly quantify the spatiotemporal dynamics of land use,we introduced the Desertification Change Index(DCI),a novel metric specifically designed to measure the transformation sensitivity of land use types.Our analysis demonstrated that from 1990 to 2020,artificial oases showed a continuous increasing trend,while desertified land decreased significantly.Natural oases decreased during 1990–2000,then continued to grow,and showed a decreasing trend again after 2015.Moreover,natural oases have mainly been converted into desertified land and artificial oases.Artificial oases were mainly converted into natural oases,and most of desertified land was converted into natural oases.Regions with significant oasis expansion(DCI=2)were mostly concentrated within the influence radius of artificial oases.In contrast,regions with significant oasis degradation(DCI=–2)were generally farther from artificial oases.Finally,this study found that the changes in land use types of the Tarim Basin are mainly driven by human activities,which play a dual role—mitigating desertification by controlling oasis expansion and exacerbating desertification through unsustainable resource utilization.Ultimately,this research provides essential insights for policy-makers and land managers aiming to devise adaptive and sustainable desertification control measures in the Tarim Basin and similarly arid regions globally.展开更多
Ecological restoration refers to the containment of soil erosion,restoration of water conservation,climate regulation,maintenance of ecological functions of biodiversity,and improvement of ecological environment and l...Ecological restoration refers to the containment of soil erosion,restoration of water conservation,climate regulation,maintenance of ecological functions of biodiversity,and improvement of ecological environment and landscape pattern based on self-repairing capacity of the nature and combined with appropriate artificial measures. Since the natural restoration process of karst desertification mountain is very long,it needs to be supplemented by artificial vegetation restoration. This paper introduced the ecological restoration technologies implemented in karst rocky desertification mountains in Xixiu District,Anshun City of Guizhou Province,and also introduced the afforestation tending management measures. It assessed the ecological benefits of the ecological restoration project from five aspects: mountain community characteristics,vegetation coverage,species diversity,afforestation survival rate and landscape effect.展开更多
Desertification is a global crucial ecological and environmental issue,and China is among the countries most seriously affected by desertification.In recent decades,numerous independent studies on desertification dyna...Desertification is a global crucial ecological and environmental issue,and China is among the countries most seriously affected by desertification.In recent decades,numerous independent studies on desertification dynamics have been carried out using remote sensing technology,but there has been a lack of systematic research on desertification trends in China.This study employed the meta-analysis to integrate the findings of 140 published research cases and examined the dynamics of desertification in the eight major deserts,four major sandy lands,and their surrounding areas in China from 1970 to 2019,with a comparative analysis of differences between the eastern(including the Mu Us Sandy Land,the Otindag Sandy Land,the Hulunbuir Sandy Land,the Horqin Sandy Land,and the Hobq Desert)and western(including the Taklimakan Desert,the Gurbantunggut Desert,the Kumtagh Desert,the Ulan Buh Desert,the Qaidam Basin Desert,the Badain Jaran Desert,and the Tengger Desert)regions.The results revealed that from 1970 to 2019,desertification first expanded and then reversed in the whole region.Specifically,desertification expanded from 1980 to 1999 and reversed after 2000.The desertification trend exhibited distinct spatio-temporal variations between the eastern and western regions.From 1970 to 2019,the western region experienced relatively minor changes in desertified land area compared to the eastern region.In the context of global climate change,beneficial climatic conditions and ecological construction projects played a crucial role in reversing desertification.These findings provide valuable insights for understanding the development patterns of desertification in the most representative deserts and sandy lands in China and formulating effective desertification control strategies.展开更多
Due to irrational human activities and extreme climate,the Qinghai-Xizang Plateau,China,faces a serious threat of desertification.Desertification has a detrimental effect on the ecological environment and socioeconomi...Due to irrational human activities and extreme climate,the Qinghai-Xizang Plateau,China,faces a serious threat of desertification.Desertification has a detrimental effect on the ecological environment and socioeconomic development.In this study,the desertification sensitivity index(DSI)model was established by integrating the spatial distance model and environmentally sensitive area index evaluation method,and then the model was used to quantitatively analyze the spatial and temporal characteristics of desertification sensitivity of the Qinghai-Xizang Plateau from 1990 to 2020.The results revealed that:(1)a general increasing tendency from southeast to northwest was identified in the spatial distribution of desertification sensitivity.The low-sensitivity areas were mostly concentrated in the Hengduan and Nyaingqêntanglha mountains and surrounding forest and meadow areas.The high-sensitivity areas were located mainly in the Kunlun and Altun mountains and surrounding decertified areas.The center of gravity of all types of desertification-sensitive areas moved to the northwest,and the desertification sensitivity showed a decreasing trend as a whole;(2)the area of highly sensitive desertification areas decreased by 8.37%,with extreme sensitivity being the largest change among the sensitivity types.The desertification sensitivity transfer was characterized by a greater shift to lower sensitivity levels(24.56%)than to higher levels(2.03%),which demonstrated a declining trend;(3)since 1990,the change in desertification sensitivity has been dominated by the stabilizing type Ⅰ(29.30%),with the area of continuously increasing desertification sensitivity accounting for only 1.10%,indicating that the management of desertification has achieved positive results in recent years;and(4)natural factors have had a more significant impact on desertification sensitivity on the Xizang Plateau,whereas socioeconomic factors affected only localized areas.The main factors influencing desertification sensitivity were vegetation drought tolerance and aridity index.Studying spatiotemporal variations in desertification sensitivity and its influencing factors can provide a scientific foundation for developing strategies to control desertification on the Qinghai-Xizang Plateau.Dividing different desertification-sensitive areas on the basis of these patterns of change can facilitate the formulation of more targeted management and protection measures,contributing to ecological construction and sustainable economic development in the area.展开更多
Land desertification severely compromises the core function of ecosystem and significantly disrupts biodiversity.Caragana korshinskii Kom.plays a pivotal role as a critical plant resource in the restoration and ecolog...Land desertification severely compromises the core function of ecosystem and significantly disrupts biodiversity.Caragana korshinskii Kom.plays a pivotal role as a critical plant resource in the restoration and ecological reconstruction of desertified areas in Northwest China.Kytorhinus immixtus Motschulsky is the primary pest responsible for causing substantial damage to the seeds of C.korshinskii.In this study,field surveys were utilized in three distinct desertified types(lightly,moderately,and severely desertified areas)in north central Ningxia Hui Autonomous Region,Northwest China.This research was focused on investigating the population dynamics and damage rates of K.immixtus,with an emphasis on examining the relationships among K.immixtus distribution,levels of soil desertification,and associated environmental factors.The results revealed marked variations in the population distribution and abundance of K.immixtus across habitats with different degrees of desertification.Due to the sand-fixing ability of C.korshinskii,the severity of soil desertification decreased progressively from severe to moderate and light with C.korshinskii establishment.This reduction in desertification,along with habitat restoration and an increase in plant diversity,was correlated with a gradual increase in K.immixtus population size and damage rate.Generalized linear mixed model analysis revealed significantly positive correlations of soil total potassium,C.korshinskii height,maximum temperature during the survey,precipitation,and the plant species richness index with K.immixtus population.In contrast,the soil total phosphorus content,organic matter content,minimum temperature during the survey,C.korshinskii canopy width,and branch number were significantly and negatively correlated with K.immixtus population.Due to the sand-fixing capacity of C.korshinskii,the plant mitigated soil desertification,but as desertification severity decreased,habitat restoration and increased plant diversity drove a gradual increase in the population and damage rate of K.immixtus.Both biotic and abiotic factors in the habitat significantly influenced K.immixtus occurrence.To achieve the sustainable restoration of desert ecosystem,optimization of plant community structure with soil nutrient management in ecological rehabilitation is necessary to balance the benefits of sand fixation with pest risks.展开更多
Tibetan alpine steppes are large and sensitive terrestrial carbon(C)reservoirs that are experiencing desertification due to global change and overgrazing,which can lead to stronger resource limitations for both above-...Tibetan alpine steppes are large and sensitive terrestrial carbon(C)reservoirs that are experiencing desertification due to global change and overgrazing,which can lead to stronger resource limitations for both above-and belowground communities.Soil nutrients,especially nitrogen(N)and phosphorus(P),are the crucial resources for plant growth and microbial metabolism.However,whether both plant and soil microbial communities in the degraded alpine steppes are limited by these soil nutrients remains unclear,which limits our understanding of the mechanisms of desertification and subsequent ecosystem restoration.Here,we evaluated potential nutrient limitations of the plant and soil microbial communities in the alpine steppe across five stages of desertification using stoichiometry-based approaches.Our results showed that soil microbial metabolism was mainly limited by C and P,and the plant N limitation and microbial C limitation were intensified while the microbial P limitation was relieved during desertification.Plant-soil-microbe interactions had significant impacts on the microbial C and P limitations,explaining 72 and 61%of the variation,respectively.Specifically,desertification ultimately affected microbial metabolic limitations by regulating soil pH,soil nutrients,and the plant N limitation.Moreover,the microbial C limitation further reduced microbial C use efficiency(CUE)with desertification,which is detrimental for organic C retention in the degraded soil.Overall,this study revealed that microbial metabolic limitations through plant-microbe interactions were the key drivers affecting soil microbial CUE,and it provided insights that can advance our knowledge of the microbial regulation of nutrient cycles and C sequestration.展开更多
In recent year,desertification has become one of the most important environmental hazards all over the world,especially in developing countries such as Iran.Understanding the factors impacting on desertification and i...In recent year,desertification has become one of the most important environmental hazards all over the world,especially in developing countries such as Iran.Understanding the factors impacting on desertification and identifying the regions with high desertification potential are essential to control this phenomenon(i.e.,desertification).The life cycle assessment(LCA)method is essential in assessing the desertification of ecosystems,especially for susceptible ecosystems with high degradation risks.The aim of the present study was to evaluate the desertification potential of Lorestan Province,Iran,based on the LCA method.We selected aridity,fire and dust as three indicators of desertification and collected data from 2000 to 2015.We divided the study area into 6 types of ecoregions according to the climate types(arid,semi-arid and dry sub-humid)and dominant species(Quercus brantii and Astragalus adscendens),and calculated the characteristic factor(CF)of each indicator(aridity,fire and dust)by combining the indicator layers and ecoregion layer of the study area.In a given ecoregion,the sum of CF values of aridity,dust and fire indicators represents the life cycle inventory(LCI)desertification value(the higher the LCI value,the greater the desertification potential).Then,we obtained the desertification potential map by combining and overlapping the ecoregions and the normalized indicators based on the LCA method.Aridity and fire exhibit significant impacts on desertification in the study area compared with dust.In the study area,semi-arid ecoregion with Quercus brantii as the dominant species is the largest ecoregion,while arid ecoregion with Quercus brantii as the dominant species is the smallest ecoregion.Arid ecoregion with Astragalus adscendens as the dominant species(LCI desertification value of 1.99)and dry sub-humid ecoregion with Quercus brantii as the dominant species(LCI desertification value of 0.79)show the highest and lowest desertification potentials,respectively.Furthermore,arid ecoregion with Quercus brantii as the dominant species also has a higher LCI desertification value(1.89),showing a high desertification potential.These results suggest the necessity of proper management and appropriate utilization in these ecoregions.In general,assessing desertification potential using the LCA method on a local and regional scale can possibly provide a new methodology for identifying and protecting areas with high degradation risks.展开更多
As a major worldwide issue,desertification poses significant threats to ecosystem stability and long-term socioeconomic growth.Within China,the Mu Us Sandy land represents a crucial region for studying desertification...As a major worldwide issue,desertification poses significant threats to ecosystem stability and long-term socioeconomic growth.Within China,the Mu Us Sandy land represents a crucial region for studying desertification phenomena.Comprehending how desertification risks are distributed spatially and what mechanisms drive them remains fundamental for implementing effective strategies in land management and risk mitigation.Our research evaluated desertification vulnerability across the Mu Us Sandy land by applying the MEDALUS model,while investigating causal factors via geographical detector methodology.Findings indicated that territories with high desertification vulnerability extend across 71,401.7 km^(2),constituting 76.87%of the entire region,while zones facing extreme desertification hazard cover 20,578.9 km^(2)(22.16%),primarily concentrated in a band-like pattern along the western boundary of the Mu Us Sandy land.Among the four primary indicators,management quality emerged as the most significant driver of desertification susceptibility,followed by vegetation quality and soil quality.Additionally,drought resistance,land use intensity,and erosion protection were identified as the key factors driving desertification sensitivity.The investigation offers significant theoretical perspectives that can guide the formulation of enhanced strategies for controlling desertification and promoting sustainable land resource utilization within the Mu Us Sandy land region.展开更多
Desertification has had a significant impact on the ecological environment of the Yellow River Basin(YRB)in China.However,previous studies on the evaluation of the ecological environment quality(EEQ)in the YRB have pa...Desertification has had a significant impact on the ecological environment of the Yellow River Basin(YRB)in China.However,previous studies on the evaluation of the ecological environment quality(EEQ)in the YRB have paid limited attention to the indicator of desertification.It is of great significance to incorporate the desertification index into the spatiotemporal assessment of the EEQ in the YRB in order to protect the ecological environment in the region.In this study,based on multi-source remote sensing data from 91 cities in the YRB,this article proposes a desertification remote sensing ecological index(DRSEI)model,which builds upon the traditional Remote Sensing Ecological Index(RSEI)model,to analyze the spatiotemporal changes in the EEQ in the YRB from 2001 to 2021.Furthermore,using the geographic detector(GD),and geographically and temporally weighted regression(GTWR)model,the study assesses the impact of human and natural factors on the EEQ in the YRB.The research findings indicate that:(1)Compared to the traditional RSEI,the improved DRSEI shows a decreasing trend in the evaluation results of the EEQ.Among the 24 cities,the change in DRSEI exceeds 0.05 compared to RSEI,accounting for 26.37%of the YRB.The remaining 67 cities have changes within a range of less than 0.05,accounting for 73.63%of the YRB.(2)The results of the GD for individual and interactive effects reveal that rainfall and elevation have significant individual and interactive effects on the EEQ.Furthermore,after the interaction with natural factors,the explanatory power of human factors gradually increases over time.The spatial heterogeneity results of GTWR demonstrate that rainfall has a strong direct positive impact on the EEQ,accounting for 98.90%of the influence,while temperature exhibits a more pronounced direct inhibitory effect,accounting for 76.92%of the influence.Human activities have a strong negative impact on the EEQ and a weak positive impact.展开更多
Du’an Yao Autonomous County is a typical area for the distribution of karst rocky desertification in Guangxi. The indices for the grades of rocky desertification are selected according to the scientific meaning of ka...Du’an Yao Autonomous County is a typical area for the distribution of karst rocky desertification in Guangxi. The indices for the grades of rocky desertification are selected according to the scientific meaning of karst rocky desertification and after the interpretative symbol system of rocky desertification. RS images are established by the landscape characteristics of Du’an karst and its TM image. Relying on RS & GIS means and taking land use map as base map, this paper conducts synthetic analysis on the 1999a TM image (126-043) and the correlation data involving landform, soil, geological map and GPS—database and photo on the spot, and brings forth a map showing the Du’an rocky desertification grades and a digital lithology map. As can be viewed from spatial correlation, the inherent connection is also illuminated between the various levels of rocky desertification and the carbonate lithology.展开更多
[Objective] The research aimed to study change law of phosphorus content of soil in karst rocky desertification region(KRD) during eco-restoration process such as Northwest Guangxi Province.[Method] The soil samples w...[Objective] The research aimed to study change law of phosphorus content of soil in karst rocky desertification region(KRD) during eco-restoration process such as Northwest Guangxi Province.[Method] The soil samples were collected from typical KRD in Pingguo County and Yizhou City.The determining quotas of different soil samples such as soil total phosphorus content and available phosphorus content were detected,in addition the soil total phosphorus content,available phosphorus content, urease activity, catalase activity and organic matter content in different soil samples were analyzed comparatively.[Result] Aspect,vegetation type and recovery time generated obviously influences on phosphorus contents in different soil samples.The concrete influence order was listed as follow: phosphorus content in soil of south slope was higher than that in soil of north slope;phosphorus content in soil where Zenia insignis Chun was planted was higher than that in soil of closed forest and that of soil where Dendrocalamus minor Var. amoen was planted,additionally,phosphorus increased with recovery time. Urease activity could be used as a monitoring index of soil fertility because it is related to the change of phosphorus content.[Conclusion] The soil of karst rocky desertification region in Northwest Guangxi Province could be recovered gradually if excessive human disturbance was stopped.If proper natural method of recovery promoted by human was taken,the recovery would reach a better result.展开更多
In the view of the desertification hazard process in Lingwu Yanchi region of Ningxia Hui Autonomous Region, the paper analyzed the interaction between the physical environment and the human activities, and discussed ...In the view of the desertification hazard process in Lingwu Yanchi region of Ningxia Hui Autonomous Region, the paper analyzed the interaction between the physical environment and the human activities, and discussed the social problems of controlling sandy land by using the way of “decreasing farming for increasing grazing” and developing agriculture and animal husbandry. The results indicated that the changes of desertification in the Quaternary geological periods was a kind of climatic geomorphic processes, and a kind of climate human processes in human history, which are mainly controlled by climatic conditions and partly interfered by human economic activities. Both of the physical environment and the human activities have double effects to aggravate or reverse the desertification.展开更多
In the Haishi Park Demonstration Base of Zhongliang Mountain in Chongqing, ecological restoration modes were established based on growth status of local plants and other natural environmental conditions, including for...In the Haishi Park Demonstration Base of Zhongliang Mountain in Chongqing, ecological restoration modes were established based on growth status of local plants and other natural environmental conditions, including forestry ecology, tourism ecology, agricultural ecology as well as the combined mode of various ecological types.展开更多
The Yarlung Zangbo River basin is a spacial zone in the south of Xizang, the types, distribution and causes of desertified lands have special features. The type, area, distribution and damage of desertification land i...The Yarlung Zangbo River basin is a spacial zone in the south of Xizang, the types, distribution and causes of desertified lands have special features. The type, area, distribution and damage of desertification land in the Yarlung Zangbo River basin are firstly analysed in detail by using latest investigation information. According to the classification criteria of desertified land types and grades, the desertified land in the Yarlung Zangbo River basin can be divided into three grades and five types: fixed sand (dune) land, semi bare sand and gravel land, semi fixed sand (dune) land, base sand and gravel land, and shifting sand (dune) land. The desertified lands in the basin are mainly distributed in the wide valley floor and tributary junction area. The main factors affecting desertification are fragile eco environment, climate warming and drying and over exploitation of land resources. The man made factors leading to desertification in the Yarlung Zangbo River basin are over cutting and over grazing, dominated by over grazing.展开更多
Understanding the evolution of karst rocky desertification (KRD) quantitatively is essential to obtain objective knowledge about the concept of KRD and the form reason of KRD, and is useful to restore KRD land. Houzha...Understanding the evolution of karst rocky desertification (KRD) quantitatively is essential to obtain objective knowledge about the concept of KRD and the form reason of KRD, and is useful to restore KRD land. Houzhaihe area located in central plateau in Guizhou Province was studied here as a representative assemblage landform and its KRD’ s evolution and driving factors were studied, based mainly on high-resolution remote sensing image in 1963, 1978, 2005 and 2010. The KRD land comprises light KRD, moderate KRD and severe KRD. The results demonstrated that the evolution process of KRD can be divided into four modes such as unchanged, weakened, fluctuated and aggravated in the study area. The KRD with no changes from 1963 to 2010, namely, unchanged mode, accounted for 43.76% of the total area of the KRD in 2010;it distributed in the area with the slope of 15° - 25° and >25° basically. Furthermore, the severe KRD distributed mainly in the areas within 300 - 600 m distance from settlement;when the distance away from the rural settlements was more than 900 m, the severe KRD declined, and its proportion was 28.6% and 10.6% in 1963 and 2010 respectively. In the peak-cluster depressions, located in central study area, the slope cropland with slope of 15° - 25° was still abounding, and was seriously rocky desertification generally. So, we propose that the existence of a large number of slope croplands is still the major driving factor of land rocky desertification. Therefore, for the rocky desertification control, the authors consider that the focal point is to alter the land use of steep-slope cropland at present.展开更多
Based on the field investigation and the analysis of soil moisture curve, it is clearly shown that there is a positive relationship between vegetation coverage rate and soil moisture capacity and soil depth in dry ho...Based on the field investigation and the analysis of soil moisture curve, it is clearly shown that there is a positive relationship between vegetation coverage rate and soil moisture capacity and soil depth in dry hot valley of the Jinsha River, and also there is a desertification process with seasonality. It is suggested that the basic factor of desertification in the area is water deficiency (seasonal drought and low soil water capacity) and the direct dynamic of desertification is soil erosion. Some effective countermeasures are presented, of which water saving planting and irrigation techniques should be firstly applied in the studied area.展开更多
Desertification research in arid and semi-arid regions has always been actively pursued.In China,the problem of desertification in Xinjiang has also received extensive attention.Due to its unique geography,many schola...Desertification research in arid and semi-arid regions has always been actively pursued.In China,the problem of desertification in Xinjiang has also received extensive attention.Due to its unique geography,many scholars have conducted corresponding research on the desertification status of Xinjiang.In this paper,we comprehensively reviewed desertification in Xinjiang,and compared the underlying mechanisms of desertification and the status of desertification conditions after the implementation of ecological control projects.On a larger scale,desertification in Xinjiang can be divided into soil salinization inside oases and sandy desertification on the edges of oases.Human activities are considered the main cause of desertification,but natural factors also contribute to varying degrees.Research on the mechanisms of desertification has effectively curbed the development of desertification,but unreasonable use of land resources accelerates the risk of desertification.For desertification control,there are several key points.First,desertification monitoring and the early warning of desertification expansion should be strengthened.Second,monitoring and reversing soil salinization also play an important role in the interruption of desertification process.It is very effective to control soil salinization through biological and chemical methods.Third,the management of water resources is also essential,because unreasonable utilization of water resources is one of the main reasons for the expansion of desertification in Xinjiang.Due to the unreasonable utilization of water resources,the lower reaches of the Tarim River are cut off,which leads to a series of vicious cycles,such as the deterioration of ecological environment on both sides of the river and the worsening of desertification.However,in recent years,various desertification control projects implemented in Xinjiang according to the conditions of different regions have achieved remarkable results.For future studies,research on the stability of desert-oasis transition zone is also significantly essential,because such investigations can help to assess the risk of degradation and control desertification on a relatively large scale.展开更多
Rapid increase in desertification is an environ-mental concern,especially for the health and sustainabil-ity of ecosystems in changing climates.How ecosystems respond to such changes may be partially understood by stu...Rapid increase in desertification is an environ-mental concern,especially for the health and sustainabil-ity of ecosystems in changing climates.How ecosystems respond to such changes may be partially understood by studying interactions and performance of critically impor-tant groups such as soil fungi functional groups.This study investigated variations in diversities of three soil fungi functional guilds(saprotrophic,symbiotic,pathogenic)and influencing abiotic factors in a Pinus densata forest on the southeast Tibetan Plateau where desertification is intense.The results indicate desertification significantly decreased the proportion of dominant fungal guild-symbiotic fungi(mean relative abundance decreasing from 97.0%to 68.3%),in contrast to saprotrophic fungi(increasing from 2.7%to 25.7%)and pathogenic(from 0.3%to 5.9%).Soil pH had the most significant impact on fungal community structure and negatively correlated with symbiotic fungal richness,which was significantly lower in arid soils,and positively correlated with saprotrophic and pathogenic fungal alpha-diversity,which were abundant.Different community struc-tures and regulators of the three fungi communities were observed,with pH,total phosphorus and ammonium(NH_(4)^(+))as the main determinants.This study links the biotic and abi-otic components during desertification and the interactions between them,and may be used as indicators of ecosystem health and for amendments to mitigate the effects of a chang-ing climate.展开更多
Increased soil erosion as a consequence of karst rocky desertification(KRD)reduces soil quality and plant diversity.Premna puberula Pamp.is a perennial understory shrub that can adapt to the harsh environment of KRD a...Increased soil erosion as a consequence of karst rocky desertification(KRD)reduces soil quality and plant diversity.Premna puberula Pamp.is a perennial understory shrub that can adapt to the harsh environment of KRD and has potential value for KRD environmental restoration.We measure morphological and photosynthetic characteristics,nutrient accumulation,and soil physical and chemical properties of two-year-old P.puberula planted in KRD habitat and non-rocky desertification areas,and investigate how it adapts to this habitat.In KRD areas,P.puberula reduces aboveground water loss by decreasing leaf area,stomatal conductance,and transpiration rate,while increasing leaf thickness,root length and number,and increases belowground biomass to absorb more water and nutrients.In KRD areas,drought leads to decreased leaf water content,stomatal conductance,intercellular CO_(2) concentration,and chlorophyll content,and decreased photosynthetic rate.Soluble sugar and protein contents increase in KRD areas in response to water stress,but pectin and flavonoid contents decrease.Correlation analysis reveals that leaf area and thickness are important functional traits that affect leaf water content and photosynthesis.Totals of leaf carbon,nitrogen,and phosphorus,along with C:N,C:P,and N:P ratios,are coupled with leaf photosynthetic characteristics and root development.Redundancy analysis reveals that available K and P,and total P,K,and N in soil mainly influence the differences in plant functional traits,explaining 95.8%,95.5%,91.1%,85.8%,and 74%of variation,respectively.We hypothesize that P.puberula reduces aboveground productivity to maintain its water balance,and acquires more water and nutrients by increasing belowground biomass.It indicates that this species adapts to arid KRD environments.展开更多
Amplicon sequencing of functional genes is a powerful technique to explore the diversity and abundance of microbes involved in biogeochemical processes. One such key process, denitrification, is of particular importan...Amplicon sequencing of functional genes is a powerful technique to explore the diversity and abundance of microbes involved in biogeochemical processes. One such key process, denitrification, is of particular importance because it can transform nitrate(NO3-) to N2 gas that is released to the atmosphere. In nitrogen limited alpine wetlands, assessing bacterial denitrification under the stress of wetland desertification is fundamental to understand nutrients, especially nitrogen cycling in alpine wetlands, and thus imperative for the maintenance of healthy alpine wetland ecosystems. We applied amplicon sequencing of the nirS gene to analyze the response of denitrifying bacterial community to alpine wetland desertification in Zoige, China. Raw reads were processed for quality, translated with frameshift correction, and a total of 95,316 nirS gene sequences were used for rarefaction analysis, and 1011 OTUs were detected and used in downstream analysis. Compared to the pristine swamp soil, edaphic parameters including water content, organic carbon, total nitrogen, total phosphorous, available nitrogen, available phosphorous and potential denitrification rate were significantly decreased in the moderately degraded meadow soil and in severely degraded sandy soil. Diversity of the soil nirS-type denitrifying bacteria communities increased along the Zoige wetland desertification, and Proteobacteria and Chloroflexi were the dominant denitrifying bacterial species. Genus Cupriavidus(formerly Wautersia), Azoarcus, Azospira, Thiothrix, and Rhizobiales were significantly(P<0.05) depleted along the wetland desertification succession. Soil available phosphorous was the key determinant of the composition of the nirS gene containing denitrifying bacterial communities. The proportion of depleted taxa increased along the desertification of the Zoige wetland, suggesting that wetland desertification created specific physicochemical conditions that decreased the microhabitats for bacterial denitrifiers and the denitrification related genetic diversity.展开更多
基金supported by the Third Xinjiang Scientific Expedition and Research Program-Investigation and Risk Assessment of Drought and Aeolian Disasters in Tarim River Basin(2021xjkk0300)the Xinjiang Tianshan Talent Program(2022TSYCLJ0002)the Basic Frontier Project of Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences(E3500201).
文摘Desertification poses a significant ecological threat to global sustainability,notably within arid regions such as the Tarim Basin surrounding the extensive Taklimakan Desert in Northwest China.This study used the Google Earth Engine(GEE)platform and Random Forest(RF)to analyze multi-temporal Landsat images to reveal desertification dynamics in the Tarim Basin spanning from 1990 to 2020.The results showed that land use types of the Tarim Basin were classified into three types:artificial oases,natural oases,and desertified land.To robustly quantify the spatiotemporal dynamics of land use,we introduced the Desertification Change Index(DCI),a novel metric specifically designed to measure the transformation sensitivity of land use types.Our analysis demonstrated that from 1990 to 2020,artificial oases showed a continuous increasing trend,while desertified land decreased significantly.Natural oases decreased during 1990–2000,then continued to grow,and showed a decreasing trend again after 2015.Moreover,natural oases have mainly been converted into desertified land and artificial oases.Artificial oases were mainly converted into natural oases,and most of desertified land was converted into natural oases.Regions with significant oasis expansion(DCI=2)were mostly concentrated within the influence radius of artificial oases.In contrast,regions with significant oasis degradation(DCI=–2)were generally farther from artificial oases.Finally,this study found that the changes in land use types of the Tarim Basin are mainly driven by human activities,which play a dual role—mitigating desertification by controlling oasis expansion and exacerbating desertification through unsustainable resource utilization.Ultimately,this research provides essential insights for policy-makers and land managers aiming to devise adaptive and sustainable desertification control measures in the Tarim Basin and similarly arid regions globally.
基金Supported by the Construction Science and Technology Plan Program of Chongqing "Study on Landscape and Ecological Restoration Technology for Karst Rocky Desertification Landforms"(2015-1-19)
文摘Ecological restoration refers to the containment of soil erosion,restoration of water conservation,climate regulation,maintenance of ecological functions of biodiversity,and improvement of ecological environment and landscape pattern based on self-repairing capacity of the nature and combined with appropriate artificial measures. Since the natural restoration process of karst desertification mountain is very long,it needs to be supplemented by artificial vegetation restoration. This paper introduced the ecological restoration technologies implemented in karst rocky desertification mountains in Xixiu District,Anshun City of Guizhou Province,and also introduced the afforestation tending management measures. It assessed the ecological benefits of the ecological restoration project from five aspects: mountain community characteristics,vegetation coverage,species diversity,afforestation survival rate and landscape effect.
基金supported by the State Key Research and Development Program of China(2023YFF1305304)the Open Bidding for Selecting the Best Candidates Project of Inner Mongolia Autonomous Region(2024JBGS0020).
文摘Desertification is a global crucial ecological and environmental issue,and China is among the countries most seriously affected by desertification.In recent decades,numerous independent studies on desertification dynamics have been carried out using remote sensing technology,but there has been a lack of systematic research on desertification trends in China.This study employed the meta-analysis to integrate the findings of 140 published research cases and examined the dynamics of desertification in the eight major deserts,four major sandy lands,and their surrounding areas in China from 1970 to 2019,with a comparative analysis of differences between the eastern(including the Mu Us Sandy Land,the Otindag Sandy Land,the Hulunbuir Sandy Land,the Horqin Sandy Land,and the Hobq Desert)and western(including the Taklimakan Desert,the Gurbantunggut Desert,the Kumtagh Desert,the Ulan Buh Desert,the Qaidam Basin Desert,the Badain Jaran Desert,and the Tengger Desert)regions.The results revealed that from 1970 to 2019,desertification first expanded and then reversed in the whole region.Specifically,desertification expanded from 1980 to 1999 and reversed after 2000.The desertification trend exhibited distinct spatio-temporal variations between the eastern and western regions.From 1970 to 2019,the western region experienced relatively minor changes in desertified land area compared to the eastern region.In the context of global climate change,beneficial climatic conditions and ecological construction projects played a crucial role in reversing desertification.These findings provide valuable insights for understanding the development patterns of desertification in the most representative deserts and sandy lands in China and formulating effective desertification control strategies.
基金funded by the National Natural Science Foundation of China(42371219)the Key Natural Science Foundation of Gansu Province(24JRRA135)the Oasis Scientific Research Achievements Breakthrough Action Plan Project of Northwest Normal University(NWNU-LZKX-202302).
文摘Due to irrational human activities and extreme climate,the Qinghai-Xizang Plateau,China,faces a serious threat of desertification.Desertification has a detrimental effect on the ecological environment and socioeconomic development.In this study,the desertification sensitivity index(DSI)model was established by integrating the spatial distance model and environmentally sensitive area index evaluation method,and then the model was used to quantitatively analyze the spatial and temporal characteristics of desertification sensitivity of the Qinghai-Xizang Plateau from 1990 to 2020.The results revealed that:(1)a general increasing tendency from southeast to northwest was identified in the spatial distribution of desertification sensitivity.The low-sensitivity areas were mostly concentrated in the Hengduan and Nyaingqêntanglha mountains and surrounding forest and meadow areas.The high-sensitivity areas were located mainly in the Kunlun and Altun mountains and surrounding decertified areas.The center of gravity of all types of desertification-sensitive areas moved to the northwest,and the desertification sensitivity showed a decreasing trend as a whole;(2)the area of highly sensitive desertification areas decreased by 8.37%,with extreme sensitivity being the largest change among the sensitivity types.The desertification sensitivity transfer was characterized by a greater shift to lower sensitivity levels(24.56%)than to higher levels(2.03%),which demonstrated a declining trend;(3)since 1990,the change in desertification sensitivity has been dominated by the stabilizing type Ⅰ(29.30%),with the area of continuously increasing desertification sensitivity accounting for only 1.10%,indicating that the management of desertification has achieved positive results in recent years;and(4)natural factors have had a more significant impact on desertification sensitivity on the Xizang Plateau,whereas socioeconomic factors affected only localized areas.The main factors influencing desertification sensitivity were vegetation drought tolerance and aridity index.Studying spatiotemporal variations in desertification sensitivity and its influencing factors can provide a scientific foundation for developing strategies to control desertification on the Qinghai-Xizang Plateau.Dividing different desertification-sensitive areas on the basis of these patterns of change can facilitate the formulation of more targeted management and protection measures,contributing to ecological construction and sustainable economic development in the area.
基金funded by the National Natural Science Foundation of China(31860619,31560611)the Natural Science Foundation of Ningxia Hui Autonomous Region,China(2021AAC02009).
文摘Land desertification severely compromises the core function of ecosystem and significantly disrupts biodiversity.Caragana korshinskii Kom.plays a pivotal role as a critical plant resource in the restoration and ecological reconstruction of desertified areas in Northwest China.Kytorhinus immixtus Motschulsky is the primary pest responsible for causing substantial damage to the seeds of C.korshinskii.In this study,field surveys were utilized in three distinct desertified types(lightly,moderately,and severely desertified areas)in north central Ningxia Hui Autonomous Region,Northwest China.This research was focused on investigating the population dynamics and damage rates of K.immixtus,with an emphasis on examining the relationships among K.immixtus distribution,levels of soil desertification,and associated environmental factors.The results revealed marked variations in the population distribution and abundance of K.immixtus across habitats with different degrees of desertification.Due to the sand-fixing ability of C.korshinskii,the severity of soil desertification decreased progressively from severe to moderate and light with C.korshinskii establishment.This reduction in desertification,along with habitat restoration and an increase in plant diversity,was correlated with a gradual increase in K.immixtus population size and damage rate.Generalized linear mixed model analysis revealed significantly positive correlations of soil total potassium,C.korshinskii height,maximum temperature during the survey,precipitation,and the plant species richness index with K.immixtus population.In contrast,the soil total phosphorus content,organic matter content,minimum temperature during the survey,C.korshinskii canopy width,and branch number were significantly and negatively correlated with K.immixtus population.Due to the sand-fixing capacity of C.korshinskii,the plant mitigated soil desertification,but as desertification severity decreased,habitat restoration and increased plant diversity drove a gradual increase in the population and damage rate of K.immixtus.Both biotic and abiotic factors in the habitat significantly influenced K.immixtus occurrence.To achieve the sustainable restoration of desert ecosystem,optimization of plant community structure with soil nutrient management in ecological rehabilitation is necessary to balance the benefits of sand fixation with pest risks.
基金supported by the National Key Research and Development Program of China(2023YFF1304304)。
文摘Tibetan alpine steppes are large and sensitive terrestrial carbon(C)reservoirs that are experiencing desertification due to global change and overgrazing,which can lead to stronger resource limitations for both above-and belowground communities.Soil nutrients,especially nitrogen(N)and phosphorus(P),are the crucial resources for plant growth and microbial metabolism.However,whether both plant and soil microbial communities in the degraded alpine steppes are limited by these soil nutrients remains unclear,which limits our understanding of the mechanisms of desertification and subsequent ecosystem restoration.Here,we evaluated potential nutrient limitations of the plant and soil microbial communities in the alpine steppe across five stages of desertification using stoichiometry-based approaches.Our results showed that soil microbial metabolism was mainly limited by C and P,and the plant N limitation and microbial C limitation were intensified while the microbial P limitation was relieved during desertification.Plant-soil-microbe interactions had significant impacts on the microbial C and P limitations,explaining 72 and 61%of the variation,respectively.Specifically,desertification ultimately affected microbial metabolic limitations by regulating soil pH,soil nutrients,and the plant N limitation.Moreover,the microbial C limitation further reduced microbial C use efficiency(CUE)with desertification,which is detrimental for organic C retention in the degraded soil.Overall,this study revealed that microbial metabolic limitations through plant-microbe interactions were the key drivers affecting soil microbial CUE,and it provided insights that can advance our knowledge of the microbial regulation of nutrient cycles and C sequestration.
文摘In recent year,desertification has become one of the most important environmental hazards all over the world,especially in developing countries such as Iran.Understanding the factors impacting on desertification and identifying the regions with high desertification potential are essential to control this phenomenon(i.e.,desertification).The life cycle assessment(LCA)method is essential in assessing the desertification of ecosystems,especially for susceptible ecosystems with high degradation risks.The aim of the present study was to evaluate the desertification potential of Lorestan Province,Iran,based on the LCA method.We selected aridity,fire and dust as three indicators of desertification and collected data from 2000 to 2015.We divided the study area into 6 types of ecoregions according to the climate types(arid,semi-arid and dry sub-humid)and dominant species(Quercus brantii and Astragalus adscendens),and calculated the characteristic factor(CF)of each indicator(aridity,fire and dust)by combining the indicator layers and ecoregion layer of the study area.In a given ecoregion,the sum of CF values of aridity,dust and fire indicators represents the life cycle inventory(LCI)desertification value(the higher the LCI value,the greater the desertification potential).Then,we obtained the desertification potential map by combining and overlapping the ecoregions and the normalized indicators based on the LCA method.Aridity and fire exhibit significant impacts on desertification in the study area compared with dust.In the study area,semi-arid ecoregion with Quercus brantii as the dominant species is the largest ecoregion,while arid ecoregion with Quercus brantii as the dominant species is the smallest ecoregion.Arid ecoregion with Astragalus adscendens as the dominant species(LCI desertification value of 1.99)and dry sub-humid ecoregion with Quercus brantii as the dominant species(LCI desertification value of 0.79)show the highest and lowest desertification potentials,respectively.Furthermore,arid ecoregion with Quercus brantii as the dominant species also has a higher LCI desertification value(1.89),showing a high desertification potential.These results suggest the necessity of proper management and appropriate utilization in these ecoregions.In general,assessing desertification potential using the LCA method on a local and regional scale can possibly provide a new methodology for identifying and protecting areas with high degradation risks.
基金the National Natural Science Foundation of China(Grant No.42301336)the Open Research Fund of Henan Provincial Key Laboratory of Hydrosphere and Watershed Water Security(Grant No.HWWSF202302).
文摘As a major worldwide issue,desertification poses significant threats to ecosystem stability and long-term socioeconomic growth.Within China,the Mu Us Sandy land represents a crucial region for studying desertification phenomena.Comprehending how desertification risks are distributed spatially and what mechanisms drive them remains fundamental for implementing effective strategies in land management and risk mitigation.Our research evaluated desertification vulnerability across the Mu Us Sandy land by applying the MEDALUS model,while investigating causal factors via geographical detector methodology.Findings indicated that territories with high desertification vulnerability extend across 71,401.7 km^(2),constituting 76.87%of the entire region,while zones facing extreme desertification hazard cover 20,578.9 km^(2)(22.16%),primarily concentrated in a band-like pattern along the western boundary of the Mu Us Sandy land.Among the four primary indicators,management quality emerged as the most significant driver of desertification susceptibility,followed by vegetation quality and soil quality.Additionally,drought resistance,land use intensity,and erosion protection were identified as the key factors driving desertification sensitivity.The investigation offers significant theoretical perspectives that can guide the formulation of enhanced strategies for controlling desertification and promoting sustainable land resource utilization within the Mu Us Sandy land region.
基金supported by the National Science Foundation of China (Grant Number: 72004116)the Hubei Social Science Foundation (Grant NO. 2022CFB292)
文摘Desertification has had a significant impact on the ecological environment of the Yellow River Basin(YRB)in China.However,previous studies on the evaluation of the ecological environment quality(EEQ)in the YRB have paid limited attention to the indicator of desertification.It is of great significance to incorporate the desertification index into the spatiotemporal assessment of the EEQ in the YRB in order to protect the ecological environment in the region.In this study,based on multi-source remote sensing data from 91 cities in the YRB,this article proposes a desertification remote sensing ecological index(DRSEI)model,which builds upon the traditional Remote Sensing Ecological Index(RSEI)model,to analyze the spatiotemporal changes in the EEQ in the YRB from 2001 to 2021.Furthermore,using the geographic detector(GD),and geographically and temporally weighted regression(GTWR)model,the study assesses the impact of human and natural factors on the EEQ in the YRB.The research findings indicate that:(1)Compared to the traditional RSEI,the improved DRSEI shows a decreasing trend in the evaluation results of the EEQ.Among the 24 cities,the change in DRSEI exceeds 0.05 compared to RSEI,accounting for 26.37%of the YRB.The remaining 67 cities have changes within a range of less than 0.05,accounting for 73.63%of the YRB.(2)The results of the GD for individual and interactive effects reveal that rainfall and elevation have significant individual and interactive effects on the EEQ.Furthermore,after the interaction with natural factors,the explanatory power of human factors gradually increases over time.The spatial heterogeneity results of GTWR demonstrate that rainfall has a strong direct positive impact on the EEQ,accounting for 98.90%of the influence,while temperature exhibits a more pronounced direct inhibitory effect,accounting for 76.92%of the influence.Human activities have a strong negative impact on the EEQ and a weak positive impact.
基金supported jointly by National Natural Science Foundation of China(Grant Nos.40161004 and 40361002)Guangxi Natural Science Foundation(Guikeji Grant No.0236046 and Guikezi Grant No.0342001-2)the Resource and Environmental Information System Laboratory project of Guangxi Teachers Education University-Guangxi Science and Technological Innovation Unit.
文摘Du’an Yao Autonomous County is a typical area for the distribution of karst rocky desertification in Guangxi. The indices for the grades of rocky desertification are selected according to the scientific meaning of karst rocky desertification and after the interpretative symbol system of rocky desertification. RS images are established by the landscape characteristics of Du’an karst and its TM image. Relying on RS & GIS means and taking land use map as base map, this paper conducts synthetic analysis on the 1999a TM image (126-043) and the correlation data involving landform, soil, geological map and GPS—database and photo on the spot, and brings forth a map showing the Du’an rocky desertification grades and a digital lithology map. As can be viewed from spatial correlation, the inherent connection is also illuminated between the various levels of rocky desertification and the carbonate lithology.
文摘[Objective] The research aimed to study change law of phosphorus content of soil in karst rocky desertification region(KRD) during eco-restoration process such as Northwest Guangxi Province.[Method] The soil samples were collected from typical KRD in Pingguo County and Yizhou City.The determining quotas of different soil samples such as soil total phosphorus content and available phosphorus content were detected,in addition the soil total phosphorus content,available phosphorus content, urease activity, catalase activity and organic matter content in different soil samples were analyzed comparatively.[Result] Aspect,vegetation type and recovery time generated obviously influences on phosphorus contents in different soil samples.The concrete influence order was listed as follow: phosphorus content in soil of south slope was higher than that in soil of north slope;phosphorus content in soil where Zenia insignis Chun was planted was higher than that in soil of closed forest and that of soil where Dendrocalamus minor Var. amoen was planted,additionally,phosphorus increased with recovery time. Urease activity could be used as a monitoring index of soil fertility because it is related to the change of phosphorus content.[Conclusion] The soil of karst rocky desertification region in Northwest Guangxi Province could be recovered gradually if excessive human disturbance was stopped.If proper natural method of recovery promoted by human was taken,the recovery would reach a better result.
文摘In the view of the desertification hazard process in Lingwu Yanchi region of Ningxia Hui Autonomous Region, the paper analyzed the interaction between the physical environment and the human activities, and discussed the social problems of controlling sandy land by using the way of “decreasing farming for increasing grazing” and developing agriculture and animal husbandry. The results indicated that the changes of desertification in the Quaternary geological periods was a kind of climatic geomorphic processes, and a kind of climate human processes in human history, which are mainly controlled by climatic conditions and partly interfered by human economic activities. Both of the physical environment and the human activities have double effects to aggravate or reverse the desertification.
文摘In the Haishi Park Demonstration Base of Zhongliang Mountain in Chongqing, ecological restoration modes were established based on growth status of local plants and other natural environmental conditions, including forestry ecology, tourism ecology, agricultural ecology as well as the combined mode of various ecological types.
文摘The Yarlung Zangbo River basin is a spacial zone in the south of Xizang, the types, distribution and causes of desertified lands have special features. The type, area, distribution and damage of desertification land in the Yarlung Zangbo River basin are firstly analysed in detail by using latest investigation information. According to the classification criteria of desertified land types and grades, the desertified land in the Yarlung Zangbo River basin can be divided into three grades and five types: fixed sand (dune) land, semi bare sand and gravel land, semi fixed sand (dune) land, base sand and gravel land, and shifting sand (dune) land. The desertified lands in the basin are mainly distributed in the wide valley floor and tributary junction area. The main factors affecting desertification are fragile eco environment, climate warming and drying and over exploitation of land resources. The man made factors leading to desertification in the Yarlung Zangbo River basin are over cutting and over grazing, dominated by over grazing.
文摘Understanding the evolution of karst rocky desertification (KRD) quantitatively is essential to obtain objective knowledge about the concept of KRD and the form reason of KRD, and is useful to restore KRD land. Houzhaihe area located in central plateau in Guizhou Province was studied here as a representative assemblage landform and its KRD’ s evolution and driving factors were studied, based mainly on high-resolution remote sensing image in 1963, 1978, 2005 and 2010. The KRD land comprises light KRD, moderate KRD and severe KRD. The results demonstrated that the evolution process of KRD can be divided into four modes such as unchanged, weakened, fluctuated and aggravated in the study area. The KRD with no changes from 1963 to 2010, namely, unchanged mode, accounted for 43.76% of the total area of the KRD in 2010;it distributed in the area with the slope of 15° - 25° and >25° basically. Furthermore, the severe KRD distributed mainly in the areas within 300 - 600 m distance from settlement;when the distance away from the rural settlements was more than 900 m, the severe KRD declined, and its proportion was 28.6% and 10.6% in 1963 and 2010 respectively. In the peak-cluster depressions, located in central study area, the slope cropland with slope of 15° - 25° was still abounding, and was seriously rocky desertification generally. So, we propose that the existence of a large number of slope croplands is still the major driving factor of land rocky desertification. Therefore, for the rocky desertification control, the authors consider that the focal point is to alter the land use of steep-slope cropland at present.
文摘Based on the field investigation and the analysis of soil moisture curve, it is clearly shown that there is a positive relationship between vegetation coverage rate and soil moisture capacity and soil depth in dry hot valley of the Jinsha River, and also there is a desertification process with seasonality. It is suggested that the basic factor of desertification in the area is water deficiency (seasonal drought and low soil water capacity) and the direct dynamic of desertification is soil erosion. Some effective countermeasures are presented, of which water saving planting and irrigation techniques should be firstly applied in the studied area.
基金the National Natural Science Foundation of China(41971017,41861144020)the Double Track Implementation Mechanism for Combating Desertification in China and the Experiences-Sharing in the Affected Countries along the Belt and Road Region(ANSO-SBA-2021-06).
文摘Desertification research in arid and semi-arid regions has always been actively pursued.In China,the problem of desertification in Xinjiang has also received extensive attention.Due to its unique geography,many scholars have conducted corresponding research on the desertification status of Xinjiang.In this paper,we comprehensively reviewed desertification in Xinjiang,and compared the underlying mechanisms of desertification and the status of desertification conditions after the implementation of ecological control projects.On a larger scale,desertification in Xinjiang can be divided into soil salinization inside oases and sandy desertification on the edges of oases.Human activities are considered the main cause of desertification,but natural factors also contribute to varying degrees.Research on the mechanisms of desertification has effectively curbed the development of desertification,but unreasonable use of land resources accelerates the risk of desertification.For desertification control,there are several key points.First,desertification monitoring and the early warning of desertification expansion should be strengthened.Second,monitoring and reversing soil salinization also play an important role in the interruption of desertification process.It is very effective to control soil salinization through biological and chemical methods.Third,the management of water resources is also essential,because unreasonable utilization of water resources is one of the main reasons for the expansion of desertification in Xinjiang.Due to the unreasonable utilization of water resources,the lower reaches of the Tarim River are cut off,which leads to a series of vicious cycles,such as the deterioration of ecological environment on both sides of the river and the worsening of desertification.However,in recent years,various desertification control projects implemented in Xinjiang according to the conditions of different regions have achieved remarkable results.For future studies,research on the stability of desert-oasis transition zone is also significantly essential,because such investigations can help to assess the risk of degradation and control desertification on a relatively large scale.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB31000000)the Second Tibetan Plateau Scientific Expedition and Research Program(No.2019QZKK0307)+1 种基金the Key Project of the Open Competition in Jiangsu Forestry(No.LYKJ[2022]01)the Jiangsu Social Development Project(BE2022792).
文摘Rapid increase in desertification is an environ-mental concern,especially for the health and sustainabil-ity of ecosystems in changing climates.How ecosystems respond to such changes may be partially understood by studying interactions and performance of critically impor-tant groups such as soil fungi functional groups.This study investigated variations in diversities of three soil fungi functional guilds(saprotrophic,symbiotic,pathogenic)and influencing abiotic factors in a Pinus densata forest on the southeast Tibetan Plateau where desertification is intense.The results indicate desertification significantly decreased the proportion of dominant fungal guild-symbiotic fungi(mean relative abundance decreasing from 97.0%to 68.3%),in contrast to saprotrophic fungi(increasing from 2.7%to 25.7%)and pathogenic(from 0.3%to 5.9%).Soil pH had the most significant impact on fungal community structure and negatively correlated with symbiotic fungal richness,which was significantly lower in arid soils,and positively correlated with saprotrophic and pathogenic fungal alpha-diversity,which were abundant.Different community struc-tures and regulators of the three fungi communities were observed,with pH,total phosphorus and ammonium(NH_(4)^(+))as the main determinants.This study links the biotic and abi-otic components during desertification and the interactions between them,and may be used as indicators of ecosystem health and for amendments to mitigate the effects of a chang-ing climate.
基金supported by the Key Core Technology Research Project for Mountainous Agriculture in Guizhou(GZNYGJHX-2023011)the Science and Technology Support Plan Project of Guizhou(2018-2797)+2 种基金the Major Special Project of Science and Technology Program in Guizhou(2017-5411-06)the Construction Project of State Engineering Technology Institute for Karst Desertification Control of China(2012FU125X13)the Construction Project of Modern Industry Technology system of traditional Chinese Medicinal Materials in Guizhou(GZCYTX-02).
文摘Increased soil erosion as a consequence of karst rocky desertification(KRD)reduces soil quality and plant diversity.Premna puberula Pamp.is a perennial understory shrub that can adapt to the harsh environment of KRD and has potential value for KRD environmental restoration.We measure morphological and photosynthetic characteristics,nutrient accumulation,and soil physical and chemical properties of two-year-old P.puberula planted in KRD habitat and non-rocky desertification areas,and investigate how it adapts to this habitat.In KRD areas,P.puberula reduces aboveground water loss by decreasing leaf area,stomatal conductance,and transpiration rate,while increasing leaf thickness,root length and number,and increases belowground biomass to absorb more water and nutrients.In KRD areas,drought leads to decreased leaf water content,stomatal conductance,intercellular CO_(2) concentration,and chlorophyll content,and decreased photosynthetic rate.Soluble sugar and protein contents increase in KRD areas in response to water stress,but pectin and flavonoid contents decrease.Correlation analysis reveals that leaf area and thickness are important functional traits that affect leaf water content and photosynthesis.Totals of leaf carbon,nitrogen,and phosphorus,along with C:N,C:P,and N:P ratios,are coupled with leaf photosynthetic characteristics and root development.Redundancy analysis reveals that available K and P,and total P,K,and N in soil mainly influence the differences in plant functional traits,explaining 95.8%,95.5%,91.1%,85.8%,and 74%of variation,respectively.We hypothesize that P.puberula reduces aboveground productivity to maintain its water balance,and acquires more water and nutrients by increasing belowground biomass.It indicates that this species adapts to arid KRD environments.
基金supported by the Natural Science Foundation of China (Grant No. 41201256)
文摘Amplicon sequencing of functional genes is a powerful technique to explore the diversity and abundance of microbes involved in biogeochemical processes. One such key process, denitrification, is of particular importance because it can transform nitrate(NO3-) to N2 gas that is released to the atmosphere. In nitrogen limited alpine wetlands, assessing bacterial denitrification under the stress of wetland desertification is fundamental to understand nutrients, especially nitrogen cycling in alpine wetlands, and thus imperative for the maintenance of healthy alpine wetland ecosystems. We applied amplicon sequencing of the nirS gene to analyze the response of denitrifying bacterial community to alpine wetland desertification in Zoige, China. Raw reads were processed for quality, translated with frameshift correction, and a total of 95,316 nirS gene sequences were used for rarefaction analysis, and 1011 OTUs were detected and used in downstream analysis. Compared to the pristine swamp soil, edaphic parameters including water content, organic carbon, total nitrogen, total phosphorous, available nitrogen, available phosphorous and potential denitrification rate were significantly decreased in the moderately degraded meadow soil and in severely degraded sandy soil. Diversity of the soil nirS-type denitrifying bacteria communities increased along the Zoige wetland desertification, and Proteobacteria and Chloroflexi were the dominant denitrifying bacterial species. Genus Cupriavidus(formerly Wautersia), Azoarcus, Azospira, Thiothrix, and Rhizobiales were significantly(P<0.05) depleted along the wetland desertification succession. Soil available phosphorous was the key determinant of the composition of the nirS gene containing denitrifying bacterial communities. The proportion of depleted taxa increased along the desertification of the Zoige wetland, suggesting that wetland desertification created specific physicochemical conditions that decreased the microhabitats for bacterial denitrifiers and the denitrification related genetic diversity.
