Search Results (74)

In recent years, China’s “greening” trend has drawn great attention. However, does this truly represent ecological improvement? This study aims to figure it out on the mountain–oasis–desert ecosystem in the rid region of Northwest China. By first exploring the vegetation changes and the influence of climate factors and human activities on these changes, we then assessed the regional ecological quality using a combination of the Remote Sensing Ecological Index (RSEI) and the InVEST Habitat Quality Model. The results revealed that the NDVI was indeed increased, but the increase was primarily driven by cropland expansion, with significant NDVI and RSEI growth confined to oases. When croplands were excluded, RSEI values dropped substantially, and 20.9% of the region shows noticeable ecological quality deterioration. Remarkably, 75% of areas with improved RSEI ratings are cultivated lands, which concealed the degradation of natural ecosystems. The InVEST model highlights intensified regional degradation, with habitat quality declining and 9.1% of grasslands converted into croplands. Hurst index projections show 47.5% of vegetation faces sustained degradation. Thus, the observed “greening” primarily reflects cropland expansion rather than ecological improvement. Natural ecosystems in mountainous and desert areas face ongoing severe degradation. This research emphasizes the urgent need for arid regions to balance agricultural expansion with ecological conservation. Full article

Our understanding of water and salt changes in the context of declining groundwater levels in the Tarim Basin remains limited, largely due to the scarcity of hydrological monitoring stations and field observation data. This study utilizes water and salt monitoring data from 474 apparent electromagnetic induction (ECa, measured by EM38-MK2 device) sites across seven oases, combined with groundwater level observation data from representative areas, to analyze the spatiotemporal changes in ECa within the oases of the Tarim Basin from 2000 to 2022. Specific results are shown below: Numerous algorithmic predictions show the ensemble learning algorithm with the smallest error explained 71% of the ECa spatial variability. The ECa was particularly effective at identifying areas where groundwater extends beyond a depth of 5 m, demonstrating increased efficacy when ECa readings exceed the threshold of 1100 mS/m. Our spatiotemporal analysis spanning the years 2000 to 2022 has revealed a significant decline in ECa values within the artificially irrigated zones of the oasis clusters. In contrast, the transitional ecotone between the desert and the oases in Atux, Aksu, Kuqa, and Luntai have experienced a significant increase in ECa value. The variations observed within the defined Zone B, where ECa values ranged from 800 mS/m to 1100 mS/m, and Zone A, characterized by ECa values exceeding 1100 mS/m, aligned with the periodic fluctuations in the groundwater drought index (GDI), indicating a clear pattern of correlation. This study demonstrated that ECa can serve as a valuable tool for revealing the spatial and temporal variations of water resources in arid zones. The results obtained through this approach provided essential references for the local scientific management of soil and water resources. Full article

Due to continuing worldwide urban expansion, research into how urban environments affect local flora/fauna has grown significantly. Studies on the impacts of urbanization on birds have explored a wide variety of behaviors (e.g., foraging, breeding, migratory), but there is little research on the impacts of cities on avian coloniality. Various urban-environmental factors may impact colonial birds. The predominance of impervious surfaces in cities, for example, has been associated with the decline of several bird species due to negative effects on availability and quality of habitat. The urban heat island effect and shifts in resource availability (e.g., food, water) may also affect colonial birds. Here, we used five years of community-science data available in eBird to investigate urban impacts on group size in Cliff Swallows (Petrochelidon pyrrhonota), an abundant colonial bird species that now breeds readily under bridges and other built structures over or near water in Phoenix, Arizona, USA. We hypothesized that, based on the colonial breeding habits of these neotropical migratory birds in this desert environment, swallows in Phoenix would form larger groups in areas with more food and water sources and with more built structures. In fact, we found that proximity to water sources and cropland, but not impervious surface density, was positively and significantly related to group size. These results suggest that, in this desert ecosystem, an abundance of food/water resources provided by humans permits Cliff Swallows to form larger social groups during breeding. Although many studies show harmful impacts of cities on local wildlife, our findings highlight how urban and/or agricultural ‘oases’ may relieve some native species from natural resource limitations and permit them to thrive and increase in group size in human-impacted environments. Full article

Woody plants serve as crucial ecological barriers surrounding oases in arid and semi-arid regions, playing a vital role in maintaining the stability and supporting sustainable development of oases. However, their sparse distribution makes significant challenges in accurately mapping their spatial extent using medium-resolution remote sensing imagery. In this study, we utilized high-resolution Gaofen (GF-2) and Landsat 5/7/8 satellite images to quantify the relationship between vegetation growth and groundwater table depths (GTD) in a typical inland river basin from 1988 to 2021. Our findings are as follows: (1) Based on the D-LinkNet model, the distribution of woody plants was accurately extracted with an overall accuracy (OA) of 96.06%. (2) Approximately 95.33% of the desert areas had fractional woody plant coverage (FWC) values of less than 10%. (3) The difference between fractional woody plant coverage and fractional vegetation cover proved to be a fine indicator for delineating the range of desert-oasis ecotone. (4) The optimal GTD for Haloxylon ammodendron and Tamarix ramosissima was determined to be 5.51 m and 3.36 m, respectively. Understanding the relationship between woody plant growth and GTD is essential for effective ecological conservation and water resource management in arid and semi-arid regions. Full article

(1) Background: As population growth accelerates, unsustainable practices such as excessive cutting and burning of desert plants in the transition zones between deserts and oases have led to widespread vegetation loss. (2) Methods: The experiment was conducted in the oasis transition zone on the southern edge of the Taklamakan Desert from 2010 to 2023 year. Among the treatments included a control group (CK), cutting in spring (CS), cutting in fall (CF), burning in spring (BS), and flood water irrigation (FI). We used high-throughput sequencing to determine soil microbial composition and diversity and routine laboratory methods to determine soil physical and chemical properties and enzyme activities. (3) Results: No significant differences in bacterial alpha diversity (Chao1, Dominance, Observed_features, Pielou_e, Shannon, and Simpson) across the different long-term disturbance patterns. In fungi, the CK treatment showed significantly higher Chao1, Shannon, and Observed_features indices compared to BS and FI. Principal component analysis revealed a substantial reduction in bacterial community diversity in BS compared to FI, while fungal communities were lower in CK and CS compared to BS, CF, and FI; (4) Conclusions: Soil moisture content, electrical conductivity, organic carbon, and the activity of the enzyme cellobiohydrolase as key factors shaping the bacterial community. For fungi, organic carbon and the β-1,4-glucosidase enzyme were the main drivers. Full article

The current conventional food system is led by large-scale agribusinesses, characterized by industrialized production and increasing distance between food production and consumption. In response, alternative food initiatives (AFIs) have typically emerged as grassroots initiatives that may not be uniformly distributed or accessible. Food deserts, areas with limited access to healthy and affordable food, are often discussed without considering food quality. Addressing this, this article aims to assess food deserts for healthy, local, and sustainable products in 11 European cities, comparing conditions before and after the implementation of innovative actions focused on shortening food chains during three years of study. The methodology involves locating alternative production and consumption spaces (APSs and ACSs) and drawing a walking distance around them, identifying densely populated areas outside these radii as food deserts. The results show that the implementation of AFIs has reduced food deserts in 9 out of 11 cities (average from 10.1% at T0 to 7.4% at Tf), opening new market opportunities for local producers and increasing consumer access to local and sustainable produce. The implementation of this study’s approach can potentially transform food deserts into food oases, enhancing food security and sustainability. Full article

Groundwater level (GWL) in dry areas is an important parameter for understanding groundwater resources and environmental sustainability. Remote sensing data combined with machine learning algorithms have become one of the important tools for groundwater level modeling. However, the effectiveness of the above-based model in the plains of the arid zone remains underexplored. Fortunately, soil salinity and soil moisture may provide an optimized solution for GWL prediction based on the application of apparent conductivity (ECa, mS/m) using electromagnetic induction (EMI). This has not been attempted in previous studies in oases in arid regions. The study proposed two strategies to predict GWL, included an ECa-based GWL model and a remote sensing-based GWL model (RS_GWL), and then compared and explored their performances and cooperation possibilities. To this end, this study first constructed the ECa prediction model and the RS_GWL with ensemble machine learning algorithms using environmental variables and field observations (474 ECa reads and 436 groundwater level observations from a mountain–oasis–desert system, respectively). Subsequently, a strategy to improve the prediction accuracy of GWL was proposed by comparing the correlation between GWL observations and the two models. The results showed that the RS_GWL prediction model explains 30% and 90% of the spatial variability in the two value domain intervals, GWL < 10 m and GWL > 10 m, respectively. The R² of the modeling and the validation of the ECa was 79% and 73%, respectively. Careful analysis of the scatter plots between predicted ECa and GWL revealed that when ECa varies between 0–600 mS/m, 600–800 mS/m, 800–1100 mS/m, and >1100 mS/m, the fluctuation ranges of the corresponding GWL correspond to 0–31 m, 0–15 m, 0–10 m, and 0–5 m. Finally, combining the spatial variability of ECa and RS_GWL spatial distribution map, the following optimization strategies were finally established: GWL < 5 m (in natural land with ECa > 1100 mS/m), GWL < 5 m (occupied by farmland from RS_GWL) and GWL > 10 m (from RS_GWL), and 3 < GWL < 10 m (speculated). In conclusion, this study has demonstrated that the integration of EMI technology has significantly improved the precision of forecasting shallow GWL in oasis plain regions, outperforming the outcomes achieved by the use of remote sensing data alone. Full article

Balancing the accuracy and the complexity of models is a well established and ongoing challenge. Models can be misleading if they are not accurate, but models may be incomprehensible if their accuracy depends upon their being complex. In this paper, semilattices are examined as an option for balancing the accuracy and the complexity of machine learning models. This is done with a type of machine learning that is based on semilattices: algebraic machine learning. Unlike trees, semilattices can include connections between elements that are in different hierarchies. Trees are a subclass of semilattices. Hence, semilattices have higher expressive potential than trees. The explanation provided here encompasses diagrammatic semilattices, algebraic semilattices, and interrelationships between them. Machine learning based on semilattices is explained with the practical example of urban food access landscapes, comprising food deserts, food oases, and food swamps. This explanation describes how to formulate an algebraic machine learning model. Overall, it is argued that semilattices are better for balancing the accuracy and complexity of models than trees, and it is explained how algebraic semilattices can be the basis for machine learning models. Full article

Background: We explore how springs and their pastures are utilised by nomadic pastoralists and how they influence interchange and conflict between the custodians of the springs and the society of pastoralists in the broader region. Methods: The custodians of three spring locations in the Afar region of Ethiopia were interviewed to identify the advantages, and the challenges, of having springs on a pastoral estate. Results: The springs provide permanent water and health benefits, are used for cooking, and provide permanent pasture for livestock. In the Dobi Valley, the groundwater supporting the springs supports a population of the palm garayto (Hyphaene thebaica), which provides thatch and a liquor derived from the sap. The custodians of the springs are baaro-mara for their homelands and they welcome and provide access to the resources of the spring to Afar outsiders, gurro-mara. Recent invasions by the Somali Issa tribe have resulted in the deaths and displacement of Afar residents at Alalo-bad and Teo. The prickly shrub Prosopis juliflora has become another invasive threat with great impacts on the livelihood of the baaro-mara at two locations. Conclusions: Springs are oases where permanent water provides perennial resources in a semi-desert. However, the tenure of these precious havens can be subject to tribal contest and the resources of the springs have been recently undermined by invasion of a plant from another continent. The removal of the incipient population of Prosopis juliflora should be a priority before it proliferates further. Full article

The Helan Mountains, situated in the heart of the desert, act as a dividing line between China’s arid and semi-arid zones. Often referred to as a “desert oasis”, they create an ecological island with a uniquely distinctive geographical location, making this area a focal point of contemporary research. Ungulates play a critical role in this ecosystem. The Alashan wapiti (Cervus canadensis alashanicus), an isolated population of China’s smallest wapiti (Cervus canadensis) subspecies, is found exclusively within the Helan Mountains Nature Reserve. The conservation of this isolated population is fraught with challenges, particularly during winter, the harshest season for northern ungulates. Winter habitats are crucial for ensuring population stability. Therefore, we used certain methods, such as factor screening and model parameter optimization to assess habitat suitability using multi-scale species distribution models. The optimized results show that suitable habitats overlap with areas of high vegetation coverage in the Helan Mountains, covering just 588.32 km², which is less than a quarter of the reserve’s total area. The bare land area and winter NDVI are the two primary factors influencing habitat suitability, with other factors having minimal impact, underscoring the critical importance of food resources for the Alashan wapiti. The limited availability of these resources poses significant conservation challenges. Our findings provide a more precise foundation for targeted habitat protection and restoration efforts. We recommend enhancing the protection and restoration of food resources, effectively conserving vegetated areas, and preventing desertification. Full article

Arid oasis ecosystems are susceptible and fragile ecosystems on Earth. Studying the interaction between deserts, oases, and impervious surfaces is an essential breakthrough for the harmonious and sustainable development of people and land in drylands. Based on gridded data such as land use and NDVI, this article analyzes the interaction characteristics between oases, deserts, and impervious surfaces in northern Egypt and examines their dynamics using modeling and geographic information mapping methods. The results show the following: In terms of the interaction between deserts and oases, the primary manifestation was the expansion of oases and the reduction of deserts. During the study period, the oases in the Nile Delta and Fayoum District increased significantly, with the area of oases in 2020 being 1.19 times the area in 2000, which shows a clear trend of advance of people and retreat of sand. The interaction between oases and impervious surfaces was mainly observed in the form of the spread of impervious surfaces on arable land into oases. During the study period, the area of impervious surfaces increased 2.32 times. The impervious surface expanded over 1903.70 km² of arable land, accounting for 66.67% of the expanded area. The central phenomenon between the impervious surface and the desert was the encroachment of the covered area of the impervious surface into the desert, especially around the city of Cairo. Population growth and urbanization are the two central drivers between northern Egypt’s oases, deserts, and impervious surfaces. The need for increased food production due to population growth has forced oases to move deeper into the desert, and occupation of arable land due to urbanization has led to increasing pressure on arable land, creating a pressure-conducting dynamic mechanism. Finally, countermeasures for sustainable regional development are suggested. Full article

The robust carbon storage (CS) capacity of terrestrial ecosystems is crucial in mitigating climate change and holds indispensable significance for global sustainable development. The diverse topography of Central Asia (CA), comprising oases, grasslands, forests, deserts, and glaciers, has fostered industries like animal husbandry, irrigation agriculture, and mining. However, the fragile arid ecosystems of CA render it highly sensitive to climate change and human activities, with their impact on the sustainable development of multifunctional landscapes in this region remaining ambiguous in the future. This study linked land use changes with multiple socio-economic and ecological indicators to predict the dynamics of land use and changes in CS in CA. The findings reveal a significant spatial heterogeneity in CS, with considerable variations among five countries driven by differences in landscape composition. Kyrgyzstan and Kazakhstan, characterized by grasslands, demonstrate higher CS per unit area, whereas Turkmenistan, dominated by barren land, exhibits the lowest CS per unit area. Strategies involving innovative development and improved biodiversity conservation have proven effective in augmenting CS. Meanwhile, high economic and population growth stimulates the expansion of cropland and urban land, reducing the CS capacity of ecosystems. This study contributes to a more precise assessment of CS dynamics in CA. Furthermore, by elucidating the interrelationships between future socio-economic development and environmental conservation in CA, it offers solutions for enhancing the conservation of multifunctional landscapes in CA. Full article

The Taklimakan Desert in northwest China stands as a significant contributor to dust storms, with its fringe oases already designated as ecologically fragile due to the severe impacts of these storms. This study focuses on Moyu County, situated on the southwest edge of the Taklimakan Desert, examining the origin and transport pathways of dust storms from 2004 to 2021. The classification involves utilizing a 36 h backward trajectory model and the k-means clustering technique, resulting in three clusters displaying distinct transport pathways and entry directions. Air pollutant concentrations at the study site corresponding to each cluster are analyzed to elucidate the contribution of dust storms from different directions. The results categorize 1952 dusty days into three categories: NE-SE (cluster 1), N-N (cluster 2), and NW-W (cluster 3). The highest frequency of dust storms, accounting for 64% of the total suspended dust weather, originates from the northeast and southeast direction (NE-SE category), with relatively weak intensity, mainly as suspended dust (71.5%). Strong sand storms predominantly occur from the northwest direction (57.8%). Cluster 1 (the southeast direction) exhibits a higher concentration of SO₂, NO₂, and CO, mainly associated with its pathway over anthropogenically polluted areas. Conversely, Cluster 3 (northwest direction) shows higher PM10 and PM2.5 concentrations due to increased wind speed and stronger dust storm intensity. The study develops dust storm early warning schemes based on 15-day advance predictions, utilizing an 18-year trajectory model and local monitoring data. This proposed warning scheme serves as a predictive tool for potential dust storm events and air pollution levels, aiding in both scientific research and policy formulation for dust storm mitigation and adaptation. The data obtained also hols relevance for conducting further scientific research in this field. Full article

The dynamic fluctuations in the soil organic carbon (SOC) stock, a fundamental part of the terrestrial ecosystem’s carbon stock, are critical to preserving the global carbon balance. Oases in arid areas serve as critical interfaces between oasis ecosystems and deserts, with land use changes within these oases being key factors affecting soil organic carbon turnover. However, the response of the soil SOC-CO₂-SIC (soil inorganic carbon) micro-carbon cycle to oasis processes and their underlying mechanisms remains unclear. Five land-use types in the Alar reclamation area—cotton field (CF), orchard (OR), forest land (FL), waste land (WL), and sandy land (SL)—were chosen as this study’s research subjects. Using stable carbon isotope technology, the transformation process of SOC in the varieties of land-use types from 0 to 100 cm was quantitatively analyzed. The results showed the following: (1) The SOC of diverse land-use types decreased with the increase in soil depth. There were also significant differences in SIC-δ¹³C values among the different land-use types. The PC(%) (0.73 g kg⁻¹) of waste land was greatly higher than that of other land-use types (p < 0.05) (factor analysis of variance). (2) The CO₂ fixation in cotton fields, orchards, forest lands, and waste land primarily originates from soil respiration, whereas, in sandy lands, it predominantly derives from atmospheric sources. (3) The redundancy analysis (RDA) results display that the primary influencing factors in the transfer of SOC to SIC are soil water content, pH, and microbial biomass carbon. Our research demonstrates that changes in land use patterns, as influenced by oasis processes, exert a significant impact on the conversion from SOC to SIC. This finding holds substantial significance for ecological land use management practices and carbon sequestration predictions in arid regions, particularly in the context of climate change. Full article

The Pazyryk Culture, situated in the Altai Mountains of Russia, Kazakhstan, Mongolia, and China, flourished for a relatively short period: 5th–3rd centuries BCE. A series of burial grounds from the later phase, 4th–mid-3rd centuries BCE, to be studied here reveal the remains of three groups of individuals of high, mid, and lower status. Within the limiting topographical and environmental confines of the local region, in contrast to the vast grasslands of the steppe and the deserts and oases of Central Asia, it is possible via the analysis of material culture and with reference to ethnographic studies to see nuances of interaction among these three groups and the regions immediately adjacent during this short period. Aided by modern scientific techniques, including DNA and isotopic analysis, together with analysis of excavated and often frozen remains, it is also possible to map out a heterarchical set of relationships within the hierarchical framework. The model developed in this unique landscape might be tested elsewhere in Eurasia as it extends the application of the notion of nonuniform socio-political organization among pastoralists noted for Bronze Age societies in the Eurasian steppe to the late Iron Age. Full article