Catena最新文献

{"title":"Soil organic carbon loss from forest road prisms in a mountainous catchment","authors":"Zaihui Yu ,&nbsp;Qinghe Zhao ,&nbsp;Yi Liu ,&nbsp;Jinhai Yu ,&nbsp;Jiliang Zhou ,&nbsp;Shengyan Ding","doi":"10.1016/j.catena.2025.108891","DOIUrl":"10.1016/j.catena.2025.108891","url":null,"abstract":"<div><div>Forest roads exacerbate water and soil loss in mountainous catchments, significantly impacting forest carbon cycling and ecological functioning. However, limited research has examined the effect of forest roads on carbon loss in these environments. In this study, we investigated soil organic carbon (SOC) loss across different erosion units (upper hillslopes, road surfaces, and road-stream slopes) within road prisms in the Xiangchagou catchment, China. We also identified the significant factors influencing SOC loss and examined their interactions. Our findings revealed that the average SOC concentrations of different erosion units in road prisms were lowest in road surfaces, where SOC losses were significantly higher than on upper hillslopes. Among different flow paths, gullies exhibited the lowest average SOC concentration, but no significant differences were observed between flow path SOC concentrations at different hillslope positions. This suggests that SOC loss is most pronounced on road surface and gullies within road prisms. In contrast, SOC loss varied significantly with hillslope positions in both partially gullied and diffused flow paths, indicating that gully development plays a critical role in determining SOC loss on road-stream slopes. Piecewise structural equation modeling showed that upper hillslope area, road surface slope, flow paths width-to-depth ratio, and roughness were significant factors influencing SOC loss within the road prism (<em>p</em> &lt; 0.05). Additionally, upper hillslope characteristics indirectly influenced SOC loss on road surfaces and flow paths, while road surface characteristics indirectly influenced the SOC loss along flow paths. These findings suggest that SOC loss induced by forest roads is driven not only by road surfaces but also by interactions among different erosion units. To mitigate SOC loss in mountainous catchments, priority should be given to managing road prisms with extensive upper hillslopes and well-developed gullies.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"253 ","pages":"Article 108891"},"PeriodicalIF":5.4,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143563031","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 agricultural terraces on landslide occurrence: Insights from a tropical mountainous region (Rwanda, Africa)","authors":"Pascal Sibomana ,&nbsp;Matthias Vanmaercke ,&nbsp;Arthur Depicker ,&nbsp;Bernard Tychon ,&nbsp;Aurélia Hubert ,&nbsp;Olivier Dewitte","doi":"10.1016/j.catena.2025.108898","DOIUrl":"10.1016/j.catena.2025.108898","url":null,"abstract":"<div><div>Agricultural terraces are a commonly applied soil and water conservation strategy on steep and intensely cultivated hillslopes. Yet agricultural terraces can lead to an increased incidence of landslides. Nevertheless, their effects on hillslope stability remain poorly studied, especially in the tropical Global South, where terraces are increasingly implemented. Here we investigate to what extent the presence of such terraces may increase the incidence of landslides in the densely-populated northwestern Rwanda. For this, we mapped three important landslide events that were triggered by distinct and intense rainfall events in the region and analyzed the relation of these landslides to the presence of terraces and other controlling factors. Based on an inventory of &gt;4,600 mostly shallow landslides in these three events, we show that landslides are about three times more likely to occur on terraced hillslopes as compared to non-terraced hillslopes. However, our results also demonstrate important variability between the events. While the effect was most pronounced for the largest 2020-event, the other two events, 2016 and 2018, showed a less clear or even negative impact of terracing on landslide occurrence. Furthermore, we observed this effect mainly on moderately to highly susceptible hillslopes and less so in areas with a very high landslide susceptibility. Landslides on terraces also tend to be slightly smaller than their counterparts in non-terraced areas. These findings have important implications for both landslide susceptibility assessment and land management.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"253 ","pages":"Article 108898"},"PeriodicalIF":5.4,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143563095","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":"Diversity of evapotranspiration and water use efficiency for complex ecosystems in the Horqin Sandy Land","authors":"Yongzhi Bao ,&nbsp;Limin Duan ,&nbsp;Xin Tong ,&nbsp;Lina Hao ,&nbsp;Tingxi Liu ,&nbsp;Guoqiang Wang ,&nbsp;V.P. Singh","doi":"10.1016/j.catena.2025.108890","DOIUrl":"10.1016/j.catena.2025.108890","url":null,"abstract":"<div><div>Water use efficiency (WUE) is an important indicator for determining the coupling relationship between the carbon and water cycles. Accurate estimation of WUE at the canopy and ecosystem scales in different types of ecosystems is of great significance for water management in arid and semi-arid regions. This study estimated evapotranspiration (ET) and its components, canopy WUE (WUEc) and ecosystem WUE (WUEe) for dune-meadow complex ecosystems in the Horqin Sandy Land using an improved dual-source ET model based on in-situ hydrometeorological, vegetation, and flux observations covering 2013–2018. Our results indicated that the improved model can accurately estimate ET and its components at both half-hourly and daily timescales. ET, vegetation transpiration (T), and T/ET in the dune-meadow complex ecosystem showed distinct step-change characteristics, following the order of mobile semi-mobile dune (MSD) &lt; semi-fixed dune (SFD) &lt; fixed dune (FD) &lt; meadow maize (MM) &lt; meadow wetland (MW), consistent with the distribution of water and vegetation conditions. WUEc varied from 1.01 to 2.78 g C Kg⁻¹ H₂O, with the largest and smallest values in MSD and MW, respectively, indicating the strong adaptability of the sandy vegetation on the MSD ecosystem to the arid environment. WUEe varied from 0.40 to 0.88 g C Kg⁻¹H₂O, with significantly lower values in dune ecosystems than in meadow ecosystems. The vegetation, soil, and water gradients were the dominant factors controlling the spatial patterns of ET, T/ET and WUE for the dune-meadow complex ecosystem. T/ET, WUEc and WUEe were comprehensively controlled by air temperature (<em>T_a</em>), soil moisture (<em>SM</em>) and leaf area index (<em>LAI</em>). As the gradient of <em>LAI</em> varies from dune to meadow ecosystems, the effects of meteorological elements on T/ET, WUEc, and WUEe gradually increased, while the effects of moisture conditions gradually weakened.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"252 ","pages":"Article 108890"},"PeriodicalIF":5.4,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143551382","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":"Spatial and temporal variability of dust flux in Sistan and its response to climate and vegetation controls","authors":"Abbas Miri ,&nbsp;Vahid Rahdari ,&nbsp;Andreas C.W. Baas","doi":"10.1016/j.catena.2025.108880","DOIUrl":"10.1016/j.catena.2025.108880","url":null,"abstract":"<div><div>Airborne dust being advected at ground level displays great spatial and temporal variation due to differences in vegetation cover and soil conditions at the emission source, changes in wind speed, and relative distances to source. This study evaluates the temporal and spatial variations of dust flux and its drivers through a rare 18-month long field monitoring campaign, from June 2022 through October 2023, across five sites downwind of lakebed dust sources (‘Hamouns’) in the Sistan region of Eastern Iran. By examining the relationship between aeolian dust flux and meteorological parameters (precipitation, temperature, relative humidity, and wind speed) and vegetation cover we were able to identify the impacts of meteorological factors and vegetation cover on regional dust flux variations. Results indicate significant differences between fluxes at the five different sites, and highest correlations with dust storm index (DSI) and number of dust storm days (DSD) recorded at one central meteorological station. Annual variations in regional dust flux are explained by differences in vegetation cover over the lakebed source areas, recorded by NDVI from satellite imagery, between the dusty seasons of 2022 and 2023, while distance from source impacts the regional variations. The mapping of regional dust flux variations allows identifying dust-hazardous areas in Sistan and the most effective mitigation measures. The highest monhtly dust flux was measured in Ghorghori (144.32 g cm-2) and the lowest in Zabol (15.7 g cm-2), suggesting that efforts to stabilize the upwind sources in Ghorghori should be prioritized.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"253 ","pages":"Article 108880"},"PeriodicalIF":5.4,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552893","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":"Dynamics of snowmelt-induced erosion on typical sloping farmland in the Mollisol region of Northeast China","authors":"Guopeng Wang,&nbsp;Keli Zhang,&nbsp;Zhuodong Zhang","doi":"10.1016/j.catena.2025.108899","DOIUrl":"10.1016/j.catena.2025.108899","url":null,"abstract":"<div><div>Snowmelt erosion significantly contributes to soil loss during spring thawing. This process is susceptible to climate change, exacerbated by global warming trends. Due to its distinctive occurrence conditions and processes, slope snowmelt erosion has received limited attention. This study visually explored snowmelt erosion dynamics through field monitoring on typical sloping farmland in Northeast China’s Mollisol region. In this study, we revealed the spatio-temporal patterns and characteristics of snowmelt runoff on slopes through continuous monitoring, and assessed the erosive effects of snowmelt runoff. Results showed that the duration of the snowmelt runoff period was lasting for 9 days. Snowmelt runoff initiated in furrows farthest from the snow belt, progressing towards it. Furrows that produced runoff earlier experienced shorter runoff periods, contrasting with longer durations in furrows that produced runoff later. The runoff exhibited an average velocity of 0.225 m/s, flow depth of 0.023 m, temperature of 5.98 ℃, sediment content of 2.02 g/L, Reynolds number of 0.32, Froude number of 0.50, shear stress of 9.69 Pa, and stream power of 2.52 N m⁻¹ s⁻¹. Hydraulic parameters showed that the flow exhibited a laminar pattern, with occasional transitions to a supercritical state. Overall, each runoff characteristic reached its peak in the early to middle stages of the snowmelt runoff period, which was also a period of intense erosion. Thawing depth showed a stronger linear correlation with runoff characteristics (<em>P</em> &lt; 0.05), excluding the Froude number. Sediment content increased as a power function with runoff characteristics (<em>P</em> &lt; 0.05), particularly the shear stress, making it the optimal parameter for predicting soil erosion. Snowmelt runoff altered the soil properties, resulting in a decrease in mean weight diameter of soil aggregates and organic matter content by 20.2 % and 6.9 %, respectively, and an increase in sand content by 5.5 %. These findings advanced the understanding of snowmelt erosion on sloping farmland and provided references for parameter settings in simulated experiments and model development.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"253 ","pages":"Article 108899"},"PeriodicalIF":5.4,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143563030","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":"Isoerodent surfaces of the continental US for conservation planning with the RUSLE2 water erosion model","authors":"H.G. Momm ,&nbsp;R.R. Wells ,&nbsp;R. ElKadiri ,&nbsp;T. Seever ,&nbsp;D. Yoder ,&nbsp;R.P. McGehee ,&nbsp;R.L. Bingner ,&nbsp;C.J.G. Darnault","doi":"10.1016/j.catena.2025.108879","DOIUrl":"10.1016/j.catena.2025.108879","url":null,"abstract":"<div><div>Soil erosion computation technology plays an important role in planning to prevent and mitigate soil loss and non-point source pollution from agricultural fields. In the US, the RUSLE2 erosion model is extensively used by conservationists to support efforts for adoption of new farm management practices and implementation of conservation alternatives. Within RUSLE2, the impact of precipitation is described by average annual rainfall erosivity (<span><math><mi>R</mi></math></span>) which is represented by a smoothly and spatially varying surface that covers the entire US, assuring consistency in erosion predictions for conservation planning. In the current RUSLE2 erosivity database, these surfaces were developed by a laborious process of analyzing and processing data by hand, so this had not been updated since 2001. In this study, a protocol to generate isoerodent surfaces for the continental US is proposed and evaluated. The methodology describes steps that integrate the official RUSLE2 calculations with proposed new methods. The newly generated surfaces were compared to official RUSLE2 erosivity surfaces and evaluated for smoothness. Results indicate agreement with RUSLE2 surfaces for absolute values but with slightly higher spatial and temporal smoothness. Further refinements include the inclusion of small events, determination of spatially varying recurrence intervals, and consideration of two-axis trend interpolation enhanced with additional weighting accounting for data gaps, which gives more weight to weather stations that have more complete datasets. The protocol provides the means for capturing long-term climatic variations impacting soil erosion in a consistent way. This protocol supports forthcoming updates to the RUSLE2 climate database and serves as a baseline for future enhancements in the characterization of changing climatological drivers impacting soil erosion.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"253 ","pages":"Article 108879"},"PeriodicalIF":5.4,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552895","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":"The relations between settlement and selected environmental features with regard to landslide hazard in the Polish Carpathians","authors":"Przemysław Śleszyński ,&nbsp;Małgorzata Kijowska-Strugała ,&nbsp;Anna Bucała-Hrabia ,&nbsp;Zofia Rączkowska ,&nbsp;Michał Kursa ,&nbsp;Zbigniew Malinowski","doi":"10.1016/j.catena.2025.108897","DOIUrl":"10.1016/j.catena.2025.108897","url":null,"abstract":"<div><div>Identification of relations between environmental conditions, including landslide occurrence, and location of settlements, is important for development policy in mountain areas. The research gap concerns the interaction between environmental factors and human settlements in relation to landslide hazard. The aim of this study is to assess the relation between housing locations and selected characteristics of the natural environment in the context of landslide risk. The paper presents the results of a detailed study, carried out in the Polish Carpathians of the relations between landslide<del>s</del> occurrence and the distribution of address points (settlements), taking into account their environmental determinants. High-resolution vector data on landslide<del>s</del> occurrence (about 70,000 polygons), land cover, relief and address points (about 537,000 address points) were used in the study. It was found that 3.1 % of addresses are located on landslides, and further 13.6 % within 100 m from them. Detailed studies were carried out in 24 communes, selected according to the following criteria: the share of address points in a given commune in the electronic database &gt; 99 % (of all address points in this commune) and share of address points on landslides &gt; 1 %. In these communes we identified 594 inhabited landslides. According to the statistical analysis, it was noted that in selected communes one of the most important factors preventing settlement on the landslides is sufficiently high share of forest area. Therefore, the proportion of forest, landslides and slopes are decisive environmental factors in determining the location of settlements on landslides. The altitude of the communes and the population density are also important. The population in these communes located at high altitudes and with high population densities is forced to settle on landslides due to the lack of suitable land for development. Knowledge of this is an important prerequisite for future land-use planning activities and settlement restructuring.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"253 ","pages":"Article 108897"},"PeriodicalIF":5.4,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143563032","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":"Erosion-induced low carbon availability exacerbates carbon loss: Insights from microbial carbon allocation and the chemo-diversity of carbon","authors":"Jia Shi,&nbsp;Ziyun Zhang,&nbsp;Zhiyong Zhang,&nbsp;Zhongmin Fan,&nbsp;Xiang Wang","doi":"10.1016/j.catena.2025.108894","DOIUrl":"10.1016/j.catena.2025.108894","url":null,"abstract":"<div><div>Soil organic carbon (SOC) availability is substantially influenced by erosion, which leads to the redistribution and loss of SOC. However, the effects of the erosion-induced changes in carbon availability on microbial carbon allocation remain unclear. Herein, we collected soils at varying depths from eroding and depositional sites within an agricultural Mollisol landscape in Northeast China. SOC was fractionated into particulate organic carbon (POC) and mineral associated organic carbon (MAOC). We determined the soil aggregates, dissolved organic matter (DOM) content, and DOM molecular composition. Short-term incubation (28 days) was conducted to measure mass-specific microbial respiration (R_mass), which serves as an indicator of microbial carbon allocation. Erosion decreased both POC and MAOC contents, resulting in SOC decreased from 10.15 to 11.46 mg g⁻¹ soil in depositional sites to 6.17 to 9.64 mg g⁻¹ soil in eroding sites. DOM in eroding sites exhibits higher aromaticity, greater extent of decomposition, and greater proportion of recalcitrant compounds (e.g., lignin-like and condensed aromatic-like compounds) than that in depositional sites. The substrate-explicit model showed low biodegradability of DOM in eroding sites. Despite the enrichment of MAOC-¹³C by 5 to 9 % in eroding sites, the increased degradation of DOM and SOC fractions did not increase microbial biomass. This led to a substantial increase of 196 % to 252 % in R_mass in eroding sites. Additionally, the eroding sites exhibited high aggregate stability. The limited accessibility and bioavailability of SOC in these areas resulted in significant energy expenditure during microbial utilization. Consequently, a greater amount of energy was necessary to decompose recalcitrant OC, such as MAOC and low-quality DOM, which ultimately led to an increase in R_mass. Therefore, the reduction in SOC content and availability in eroding sites may further hinder the accumulation of microbial residues, as additional carbon is required for respiration and enzymatic secretion during the formation of microbial biomass.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"252 ","pages":"Article 108894"},"PeriodicalIF":5.4,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143551395","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":"Projected alterations in snowmelt streamflow with climate change in Shiyang River Basin of Northwest China using modified SWAT model","authors":"Jun Dai ,&nbsp;Haizhu Hu ,&nbsp;Xiaomin Mao ,&nbsp;Ji Zhang","doi":"10.1016/j.catena.2025.108884","DOIUrl":"10.1016/j.catena.2025.108884","url":null,"abstract":"<div><div>The timing and magnitude of snowmelt are changing due to global warming, posing significant implications for irrigated agricultural areas reliant on snowmelt streamflow. By taking the Shiyang River Basin (SRB) in Northwest China as the study area, this study focuses on accurately quantifying the snowmelt derived streamflow and its variation under the impacts of future climate change. Based on the observation data, we modified the snowmelt factor seasonal variation formula in the source code of the Soil and Water Assessment Tool (SWAT) to improve the simulation capability. Results show that the original SWAT model tends to overestimate streamflow, whereas the enhanced model (SWAT-s) aligns more closely with measured streamflow during both calibration and validation periods. The SWAT-s improves the snowmelt streamflow simulation performance and outperforms SWAT in capturing the monthly streamflow peak, especially in springtime. Furthermore, we integrated SWAT and SWAT-s with the bias-corrected 6th International Coupled Model Comparison Program (CMIP6) under four Shared Socio-economic Pathways (SSP) scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5) to investigate the projected alteration in future streamflow, evapotranspiration, snowmelt, and soil water content. Compared with the baseline period (1985–2014), a decrease in annual streamflow but an increase in snowmelt streamflow in early spring was projected in the upper reaches of the SRB over the next 78 years (2023–2100). Evapotranspiration showed a significantly increasing trend, while snowmelt and soil water content showed a significantly decreasing trend (P &lt; 0.05) under the SSP5-8.5 scenario. The study provides the scientific basis for developing streamflow management plans to ensure the sustainable development of arid areas in Northwest China.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"252 ","pages":"Article 108884"},"PeriodicalIF":5.4,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143550784","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":"Afforestation and wildfire-induced grassland degradation: Impact on soil carbon dynamics in temperate grasslands, Drakensberg, South Africa","authors":"Lindokuhle X Dlamini ,&nbsp;Jean Lévêque ,&nbsp;Mathieu Thevenot ,&nbsp;Gregor T Feig ,&nbsp;Olivier Mathieu ,&nbsp;Elmarie Kotzé","doi":"10.1016/j.catena.2025.108886","DOIUrl":"10.1016/j.catena.2025.108886","url":null,"abstract":"<div><div>Mountains in high-rainfall temperate regions store significant amounts of soil organic carbon (SOC). Afromontane grasslands in South Africa, coevolved with fire and provide various ecosystem services (biodiversity, water delivery, carbon storage). While afforestation is proposed as a nature-based solution to climate change, knowledge on its postfire impact on SOC dynamics in fire-prone grasslands is limited. This study, conducted in the Cathedral Peak Research Catchments (initiated in the 1940 s), investigates the impact of afforestation and the subsequent wildfire on SOC dynamics in Afromontane grasslands. This study compared a degraded catchment (CP-III), afforested with <em>Pinus patula</em> in 1958 but burned in a 1981 wildfire, to a natural grassland catchment (CP-VI) maintained through prescribed biennial burns. The wildfire completely removed <em>P. patula</em>, resulting in extensive soil erosion and bracken fern (<em>Pteridium aquilinum</em>) invasion. Soil samples were collected across slope positions to a 1-meter depth to quantify SOC stocks, δ¹³C signature, active carbon (C), and total microbial activity. Results showed SOC is transported downslope in the degraded catchment due to accelerated soil erosion. This catchment had two-fold SOC stocks, active C, and microbial activity in the bottom slope compared to the natural grassland catchment. Despite the dominance of bracken fern, SOC in this catchment was primarily derived from C₄ grasses and indicated little legacy of <em>P. patula</em> plantation. These findings are highly relevant to current policies that advocate tree planting, even in regions with substantial pre-existing SOC stocks. This study cautions against large-scale tree planting in fire-adapted systems because of the unintended consequences of afforestation, where wildfire-induced degradation leads to SOC loss and redistribution. Afromontane grasslands show better long-term SOC storage than afforestation in fire-prone regions.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"252 ","pages":"Article 108886"},"PeriodicalIF":5.4,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143551381","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}