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{"title":"Nitrogen-fixing tree species enhance the positive effects of tree species richness on soil organic carbon sequestration by increasing fine root phosphorus loss","authors":"Yanchun Liu ,&nbsp;Qinglin Li ,&nbsp;Huimin Tian ,&nbsp;Shirong Liu ,&nbsp;Chuang Ma ,&nbsp;Menghan Wang ,&nbsp;Hui Wang ,&nbsp;Angang Ming","doi":"10.1016/j.catena.2025.108927","DOIUrl":"10.1016/j.catena.2025.108927","url":null,"abstract":"<div><div>Mixed planting of multiple tree species and introducing nitrogen (N)-fixing tree species have been regarded as the most effective methods to enhance the ecological function of planted forests. Although there is increasing concern about the effects of tree richness on litter decomposition, knowledge gap still exists about whether N-fixing tree species regulate the effect of tree richness on soil organic carbon (SOC) sequestration by changing fine root decomposition. A 9-year tree species richness experiment with four species gradients (1, 2, 4, and 6 species) interacted with N-fixing tree species was conducted in subtropical forests. Fine root decomposition rate and changes in SOC based on an <em>in situ</em> microcosm incubation were measured to determine the effects of tree species richness and N-fixing tree species on fine root decomposition and SOC storage. We found that tree species richness positively affected fine root C, N, and phosphorus (P) loss. Regardless of the effects of tree richness, the presence of N-fixing tree species enhanced P loss by 30.6%. The increased SOC induced by fine root decomposition showed a positive non-linear response to tree species richness. The presence of N-fixing trees amplified the promoting effects of tree species richness on the net accumulation of SOC by 54.6% probably attributed to the alleviated soil P limitation calculated by soil extracellular enzyme stoichiometry, due to the stimulated root P release and soil available P content. This study demonstrates that the presence of N-fixing tree species significantly enhances the positive effects of tree species richness on SOC storage in subtropical forests. This process is driven by the accelerated release of root P, which alleviates soil P limitation and promotes microbial activity. These findings underscore the critical role of N-fixing tree species in enhancing the ecological functionality of mixed plantations through improved nutrient cycling and C sequestration.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"254 ","pages":"Article 108927"},"PeriodicalIF":5.4,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143601747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Divergent responses and roles of soil bacterial and fungal communities in shrub encroachment: A meta-analysis","authors":"Yingjie Zhu ,&nbsp;Liming Lai ,&nbsp;Jihua Zhou ,&nbsp;Qiaoe Chen ,&nbsp;Yanpeng Yue ,&nbsp;Ganggang Yang ,&nbsp;Hui Du ,&nbsp;Yuanrun Zheng","doi":"10.1016/j.catena.2025.108926","DOIUrl":"10.1016/j.catena.2025.108926","url":null,"abstract":"<div><h3>Aims</h3><div>Shrub encroachment, a global phenomenon, not only alters aboveground biodiversity but also affects belowground soil microbial community structure and composition. This study aims to investigate the effects of shrub encroachment on soil microbial communities and explore the underlying mechanisms.</div></div><div><h3>Methods</h3><div>A meta-analysis of 180 sets of observational data from 69 published studies worldwide was conducted to assess the influence of shrub encroachment on soil microbial communities and their response mechanisms.</div></div><div><h3>Results</h3><div>Shrub encroachment significantly increased soil total PLFA (3.8 %), with no significant change in fungal biomass. Shrub encroachment increased both bacterial and fungal diversity, with a stronger influence on fungal diversity (7.2 %) than on bacterial diversity (4.3 %). Moreover, the effects of shrub encroachment on soil microorganisms differed across climate zones, seasons, and soil depths. Structural equation modeling suggested that bacterial diversity increased with soil organic carbon and decreased with soil water content under shrub encroachment, whereas decreasing pH significantly enhanced fungal diversity.</div></div><div><h3>Conclusions</h3><div>This study demonstrated that shrub encroachment significantly influenced soil microbial communities, leading to changes in microbial diversity and composition. Soil physical and chemical properties and climatic factors jointly regulate the effects of shrub encroachment on soil microbial communities.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"254 ","pages":"Article 108926"},"PeriodicalIF":5.4,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143601804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of substrate quality, temperature, and water content on the decomposition of Sphagnum peat","authors":"Charuni Jayasekara ,&nbsp;Catherine Leigh ,&nbsp;Jeff Shimeta ,&nbsp;Ewen Silvester ,&nbsp;Samantha PP Grover","doi":"10.1016/j.catena.2025.108907","DOIUrl":"10.1016/j.catena.2025.108907","url":null,"abstract":"<div><div>Peatlands, with their high water tables and anoxic conditions, have inherently low organic matter decomposition rates, making them vital carbon reservoirs. We designed a laboratory incubation experiment to investigate the interactive effects of substrate quality, temperature, and water content on the decomposition rate of <em>Sphagnum</em> peat. Fresh and degraded peat was collected from three different depths (0–5, 5–15, and 15–30 cm) of an Australian alpine peatland. The water contents of the peat samples were adjusted to four levels (field-moist or 50 %, 400 %, or 1500 %) and incubated at four temperatures (7, 14, 21, and 28 °C) for 70 days. Overall, fresh peat had ∼ 50 % higher decomposition rate than degraded peat. Both fresh and degraded peat incubated at 7 °C had higher or similar decomposition rates to peat at 14 °C, regardless of water content, likely due to the <em>Sphagnum</em> peat being dominated by psychrophilic microbes that have optimal metabolism at low temperatures. Further, the duration for which peat at 7 °C had a higher decomposition rate than at 14 °C declined as water content declined in the fresh peat and as peat depth increased in degraded peat. These findings indicate that the decomposition rate of fresh peat with a high percentage of labile carbon content is determined by the availability of liquid water required for microbial metabolism, while in degraded peat, substrate availability controls the decomposition rate. Our study provides critical insights into carbon release dynamics in southern hemisphere <em>Sphagnum</em> peatlands, which can inform strategies for managing and conserving these critical carbon reservoirs.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"254 ","pages":"Article 108907"},"PeriodicalIF":5.4,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143610972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"137Cs and 210Pbex tracing of soil erosion and organic carbon dynamics in relation to the Grain-for-Green project in the Hilly area of the Central Sichuan Basin","authors":"Tao Zhou ,&nbsp;Zheng’an Su ,&nbsp;Gangcai Liu ,&nbsp;Jianhui Zhang ,&nbsp;Xinbao Zhang ,&nbsp;Xiaojian Xie ,&nbsp;Ling Zhou","doi":"10.1016/j.catena.2025.108922","DOIUrl":"10.1016/j.catena.2025.108922","url":null,"abstract":"<div><div>The Grain-for-Green project (GFGP) is one of the world’s largest ecological restoration projects and has profoundly decreased soil erosion and increased soil organic carbon (SOC) accumulation. No clear conclusion regarding changes in soil erosion and the impacts of soil erosion on carbon dynamics in the Sichuan Basin due to the GFGP has been reached. Four sample sites, reference land (RL), cultivated land (CL), and land where the GFGP was implemented in 1999 (GFGP99) and 1972 (GFGP72), were selected to investigate the impacts of the GFGP on soil erosion and SOC dynamics via combined application of ¹³⁷Cs and ²¹⁰Pb_ex in the Sichuan Basin, Southwest China. The different depth distributions and landscape positions of ¹³⁷Cs, ²¹⁰Pb_ex and SOC in CL, GFGP99 and GFGP72 indicate that the GFGP significantly reduced soil erosion and increased the SOC concentration. The eroded soil thickness decreased by 325 % and 255 % in GFGP99 and GFGP72, respectively, relative to CL. The soil redistribution rates estimated by the revised ²¹⁰Pb_ex mass balance model ranged from 65.33 to −25.18 Mg ha⁻¹ yr⁻¹ and from 18.83 to −138.74 Mg ha⁻¹ yr⁻¹ before and after GFGP implementation, respectively. The SOC densities of GFGP99 and GFGP72 were 14.83 % and 36.84 % greater than those of CL, respectively. Notably, relatively low correlations were found among the ¹³⁷Cs, ²¹⁰Pb_ex and SOC densities, which is possibly related to the coupled effects of SOC transport and input during soil erosion. More attention should be given to the limitations of estimating soil redistribution rates and SOC dynamics using fallout radionuclides, such as ¹³⁷Cs and ²¹⁰Pb_ex, on slopes following reforestation due to land-use changes.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"254 ","pages":"Article 108922"},"PeriodicalIF":5.4,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143610973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Freeze-thaw characteristics of seasonal frozen soil in Asian mid-latitude deserts: A case study of typical deserts in northern China","authors":"Tianbo Xia,&nbsp;Ping Zhang,&nbsp;Yaling Hu,&nbsp;Juanli Ma,&nbsp;Juntian Lin,&nbsp;Yuan Liu,&nbsp;Lei Jin","doi":"10.1016/j.catena.2025.108881","DOIUrl":"10.1016/j.catena.2025.108881","url":null,"abstract":"<div><div>Vast deserts and sandy lands in the mid-latitudes cover an area of 17.64 × 10⁶ km², with 6.98 × 10⁶ km² experiencing seasonal frozen soil (SFG). Freeze-thaw cycles of SFG significantly influence local surface processes in deserts, impacting meteorological disasters such as infrastructure failures and sandstorms. This study investigates the freeze–thaw dynamics of SFG in crescent dunes from three deserts in northern China: the Tengger Desert, Mu Us Sandy Land, and Ulan Buh Desert, over the period from 2019 to 2024.Freezing occurs from November to January, followed by thawing from January to March. The thawing rate (2.72 cm/day) was 1.8 times higher than the freezing rate (1.48 cm/day). The maximum seasonal freezing depth (MSFD) exceeded 0.80 m at all dune slopes, with depths surpassing 1.10 m at the leeward slope and lower slope positions. Soil moisture content, ranging from 1 % to 1.6 %, is critical for freezing, and this threshold varies depending on the dune’s mechanical composition. The hardness of frozen desert soil is primarily controlled by moisture, along with temperature and particle size.Temperature initiates freezing, while moisture and particle size control the resulting hardness.These findings shed light on the seasonal freeze–thaw processes in desert soils and have practical implications for agricultural management, engineering design, and environmental hazard mitigation in arid regions.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"254 ","pages":"Article 108881"},"PeriodicalIF":5.4,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143601803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heterogeneous responses of soil nitrous oxide emissions to nitrogen addition: A global meta-analysis","authors":"Peng Guo,&nbsp;Jingwen Diao,&nbsp;Tian Zuo,&nbsp;Han Zhao,&nbsp;Dongyan Kong,&nbsp;Lingfang Yang,&nbsp;Mengyu Miao","doi":"10.1016/j.catena.2025.108923","DOIUrl":"10.1016/j.catena.2025.108923","url":null,"abstract":"<div><div>Many projects have demonstrated that nitrogen (N) addition accelerates the emission of nitrous oxide (N₂O) from soils. However, the response ratios of N₂O emission to N (<em>ΔE</em>_N2O) exhibit significant spatial heterogeneity across global sites. Here, a <em>meta</em>-analysis was performed to explain the heterogeneity of <em>ΔE</em>_N2O through the characteristics of sample sites based on the data from 108 field experiments. Results showed that the Mean Annual Precipitation (MAP) and Mean Annual Temperature (MAT) of sample sites exerted significantly positive effects on <em>ΔE</em>_N2O on a global scale, particularly in regions with high MAP (&gt; 1,100 mm) or MAT (&gt; 15 °C). However, <em>ΔE</em>_N2O was affected by soil pH only in the sites with acidic soils (pH &lt; 5.5). In addition, <em>ΔE</em>_N2O was significantly affected by soil properties in soils with high total organic carbon (&gt; 50 g/kg), high carbon-to-nitrogen (C:N) ratio (&gt; 15), or low total N (&lt; 2.0 g/kg). Among all these factors, C:N ratio and pH, and ambient N deposition rate were the most important. Further analysis revealed that increased MAP led to a decrease in C:N ratio, while elevated ambient N deposition rate resulted in a serious decline in pH and C:N ratio, indicating that environmental conditions may indirectly affect <em>ΔE</em>_N2O through directly influencing soil properties. In sum, when comprehensively evaluating soil N₂O emissions induced by atmospheric N deposition, the characteristics of sample sites (environmental conditions and soil properties), as well as their direct and/or indirect effects should be systematically considered.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"254 ","pages":"Article 108923"},"PeriodicalIF":5.4,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143601805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating climate change impacts on runoff and sediment transport processes in the midstream of the Yarlung Tsangpo river based on hydrological simulation","authors":"Li Wang ,&nbsp;Fan Zhang ,&nbsp;Yao Chen ,&nbsp;Xiaonan Shi ,&nbsp;Chen Zeng ,&nbsp;Yuchun Wang ,&nbsp;Cicheng Qiangba ,&nbsp;Baimu Deji ,&nbsp;Dunzhu Awang ,&nbsp;Na Qiong","doi":"10.1016/j.catena.2025.108920","DOIUrl":"10.1016/j.catena.2025.108920","url":null,"abstract":"<div><div>Runoff and sediment transport are critical concerns for water resource management and ecological security in the Tibetan Plateau. The midstream of the Yarlung Tsangpo River, a central habitat and cultural epicenter, was selected as the study area. Soil and Water Assessment Tool (SWAT), sensitivity analysis and redundancy analysis (RDA) were employed to investigate these processes. Results indicate annual runoff depth is 388.8 mm, with surface runoff, lateral flow, and groundwater components accounting for 47.2 %, 24.4 %, and 28.4 %, respectively. Estimated annual soil erosion, outlet sediment flux, and river channel sediment deposition rates are 7.11 × 10⁸ t, 0.19 × 10⁸ t and 6.92 × 10⁸ t, respectively. Despite increases in runoff and its components, as well as soil erosion, and sediment deposition rates during 1983 to 2017, outlet sediment flux increased initially and decreased after implementation of Zangmu Reservoir in 2010. Soil erosion and sediment deposition exhibited significant spatial variations, with both being obviously higher in downstream areas compared to upstream regions. RDA reveals that precipitation was the primary factor explaining the variabilities in both runoff and sediment transport. In addition, the unfrozen area ratio influenced these processes by enhancing soil permeability and evaporation, thereby reducing runoff and sediment-carrying capacity. In contrast, glacier melt enhanced both runoff and sediment transport, with runoff and sediment flux sensitivity to temperature shifting from negative to positive as glacier area ratio increases. These findings provide valuable insights into the hydrological and sediment transport mechanisms in high mountain areas, offering a scientific foundation for integrated soil and water conservation strategies.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"254 ","pages":"Article 108920"},"PeriodicalIF":5.4,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143601802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of reindeer grazing on thermal stability of organic matter in topsoil in Arctic tundra","authors":"Ekaterina Filimonenko ,&nbsp;Maria Uporova ,&nbsp;Ekaterina Dimitryuk ,&nbsp;Nataliya Samokhina ,&nbsp;Tida Ge ,&nbsp;Abeer S. Aloufi ,&nbsp;Nikolai Prikhodko ,&nbsp;Yakov Kuzyakov ,&nbsp;Andrey Soromotin","doi":"10.1016/j.catena.2025.108928","DOIUrl":"10.1016/j.catena.2025.108928","url":null,"abstract":"<div><div>Reindeer grazing is a geochemical factor of carbon (C) and nutrient cycling in high-latitude ecosystems. Reindeer consume and trample aboveground biomass, and return nutrients by urine and faces on soil surface. Degradation of vegetation cover due to overgrazing induces soil warming, decreases soil organic matter (SOM) content, and affects its stability. We investigated the effects of reindeer grazing on the thermal stability and temperature sensitivity (Q₁₀) of SOM decomposition in the Gydan Arctic tundra. Thermogravimetric analysis of the topsoil (0–5 cm) from grazed and ungrazed tundra was used to divide SOM into three thermal pools – labile, stable, and persistent. The thermally labile pool contributed 62 % to SOM, reflecting large portion of partly decomposed plant litter. The thermal stability of SOM was evaluated by the temperature, at which the half of the organic matter was lost (T₅₀), and by the activation energy of SOM combustion (E_{a TG}). Reindeer grazing increased the thermal stability of SOM in tundra by decrease in the thermally labile SOM content, as well as increase in T₅₀ and E_{a TG}. The decrease in the labile SOM content in grazed compared to ungrazed tundra explained the reduction of soil microbial respiration at sites under reindeer grazing. The CO₂ efflux from the ungrazed and grazed soils at increasing temperatures was used to investigate the Q₁₀ of SOM decomposition. A 10 °C increase in soil temperature accelerated microbial SOM decomposition by 3.1 and 2.9 times in ungrazed and grazed tundra soils, respectively. Concluding, reindeer grazing in the Arctic tundra decreased SOM content in topsoil and increased the thermal stability of the remaining organic matter.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"254 ","pages":"Article 108928"},"PeriodicalIF":5.4,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143601748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Restoration of soil health by Amazonian secondary forests is severely eroded by slash-and-burn recurrence","authors":"Wanderlei Bieluczyk ,&nbsp;Marina Pires Duarte ,&nbsp;Plínio Barbosa de Camargo ,&nbsp;Norberto Cornejo Noronha ,&nbsp;Marisa de Cássia Piccolo ,&nbsp;Siu Mui Tsai","doi":"10.1016/j.catena.2025.108925","DOIUrl":"10.1016/j.catena.2025.108925","url":null,"abstract":"<div><div>Secondary forest regeneration is a promising path to restore soil health in the Amazon, but slash-and-burn for agricultural reconversion may reverse decades of the soil’s multifunctional progress. This study examined (i) how secondary forests rehabilitate soil multifunctionality after long-term agriculture in the eastern Amazon and (ii) the extent of soil functional loss if the forest is re-burned after two decades of ecological restoration. We investigated contiguous secondary forests at 2, 5, and 20 years, including post-slash-and-burn of the 20-year-old forest, all on soils with over 85 % sand on a small farm practicing shifting agriculture. We structured a soil health assessment using thirteen physical, chemical, and biological soil indicators, and calculated index scores based on soil functions. Secondary forests improved soil aggregation, cation exchange capacity, and nitrogen and carbon levels, enhancing soil’s physical, chemical, and biological functions and increasing soil multifunctionality by 13 % over 18 years. While slash-and-burn increased available P and exchangeable Ca, Mg, and K, nutrient levels remained poor for cassava cultivation on the farm. Furthermore, nitrogen, cation exchange capacity, carbon, macrofauna indexes, and aggregate stability dropped to levels comparable to<!--> <!-->or lower than the 2-year-old forest, reducing the<!--> <!-->soil health score by 11 %. We conclude that secondary forests effectively restore soil multifunctionality in the eastern Amazon, but a single slash-and-burn recurrence reverses two decades of soil health recovery. We advocate educational and socioeconomic support for small farmers reliant on slash-and-burn, promoting sustainable agroforestry and compensating those who perpetuate secondary forests, given their soil health benefits demonstrated in this study.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"254 ","pages":"Article 108925"},"PeriodicalIF":5.4,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143611071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Glaciers retreat-induced gravelization encroached alpine hillside grassland: A case study in Qilian Mountain, China","authors":"Tong Li ,&nbsp;Jingxue Zhao ,&nbsp;Gao-Lin Wu","doi":"10.1016/j.catena.2025.108905","DOIUrl":"10.1016/j.catena.2025.108905","url":null,"abstract":"<div><div>The current global warming is accelerating deglaciation in polar regions, directly or indirectly threatening terrestrial environment and conservation. During deglaciation, a climate warming-induced secondary disaster − gravelization encroachment in alpine hillside grassland appears as a threat of alpine grassland ecosystem, however, this phenomenon remains largely overlook. Here, we mapped in detail gravelization in alpine hillside grassland by a representative glacier as a case study, and aggregated all available surface reflectance Landsat 5 TM and Landsat 8 OLI_TIRS images covering study area between 1987 and 2019 based on Google Earth Engine. Annual cell-specific Normalized Difference Vegetation Index (NDVI) values were calculated for the Maximum Value Composites, and cell-by-cell non-parametric Sen’s slopes were computed. The high resolution (0.5 m) remote sensing images taken in 2008 and 2019 were interpreted to validate Sen’s slopes analysis of NDVI. We found that glaciers retreated as average annual temperature increased from the period between 1987 and 2019, with a total melting area ratio of 65.02 %. More importantly, after glacier retreat, the gravel debris fragments accelerated sliding, covering and reducing the alpine grassland area. NDVI value at the grassland − gravel debris interface showed a decreasing trend, especially after 2000. Gravel debris expansion caused the loss of 12.98 ha of alpine grassland between 2008 and 2019. Overall, as a consequence of the current climate change, the gravel debris covered area replaced the glacier and grassland gradually, giving rise to this emerging surficial process. Gravelization encroachment in alpine hillside grassland has profound implications for alpine grassland ecosystem that should be paid more attention in future studies.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"254 ","pages":"Article 108905"},"PeriodicalIF":5.4,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143591713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}