Yeye Liu, Jinjiao Lian, Yunpeng Nie, Kelin Wang, Hongsong Chen
{"title":"根区土壤水分在延缓植被对干旱响应中的作用:喀斯特和非喀斯特地区的比较见解","authors":"Yeye Liu, Jinjiao Lian, Yunpeng Nie, Kelin Wang, Hongsong Chen","doi":"10.1016/j.jhydrol.2025.134216","DOIUrl":null,"url":null,"abstract":"<div><div>Vegetation loss occurs when soil moisture falls below a critical threshold, above which vegetation can withstand drought stress. Root-zone soil moisture (SM<sub>root</sub>) is crucial for enhancing drought resistance and sustaining ecosystem stability, yet its role in shaping drought thresholds and how these thresholds differ between karst and non-karst regions remains poorly understood. Here, we quantified drought thresholds (T<sub>SM</sub>) from both surface soil moisture (SM<sub>surf</sub>) and SM<sub>root</sub> across contrasting lithologies to evaluate how geological settings modulates vegetation drought responses. We found pronounced spatial heterogeneity in T<sub>SM</sub>, with higher values in the peak forest plain (14.7th percentile) and basins, reflecting heightened atmospheric demand and greater drought vulnerability, whereas lower values in the karst plateau and gorge (10.3rd percentile) indicated stronger drought resistance. T<sub>SM</sub> exhibited a significant increasing trend during 2001–2018, implying a gradual decline in drought resistance. SM<sub>root</sub>-based thresholds (11.3rd percentile) were consistently lower than those derived from SM<sub>surf</sub> (12.9th percentile), highlighting the role of SM<sub>root</sub> in delaying the onset of drought stress. Karst ecosystems exhibited lower T<sub>SM</sub> than non-karst systems, especially in croplands and forests, indicating that vegetation in karst landscapes operates under drier conditions yet maintains higher drought tolerance. However, projections under future climate scenarios reveal greater drought risks in karst ecosystems, particularly under strong warming. Furthermore, climatic controls on T<sub>SM</sub> also differed between lithologies: in non-karst regions, thresholds responded coherently to plant-available water, whereas in karst regions, correlations with plant-available water alternated between positive and negative. This contrasting behavior suggests that karst vegetation flexibly shifts between shallow soil moisture and deeper bedrock water. These findings underscore the critical role of SM<sub>root</sub> in mitigating drought impacts and reveal that geological settings shape ecosystem drought resilience under changing climates.</div></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":"663 ","pages":"Article 134216"},"PeriodicalIF":6.3000,"publicationDate":"2025-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"The role of root-zone soil moisture in delaying vegetation responses to drought: Comparative insights from karst and non-karst areas\",\"authors\":\"Yeye Liu, Jinjiao Lian, Yunpeng Nie, Kelin Wang, Hongsong Chen\",\"doi\":\"10.1016/j.jhydrol.2025.134216\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Vegetation loss occurs when soil moisture falls below a critical threshold, above which vegetation can withstand drought stress. Root-zone soil moisture (SM<sub>root</sub>) is crucial for enhancing drought resistance and sustaining ecosystem stability, yet its role in shaping drought thresholds and how these thresholds differ between karst and non-karst regions remains poorly understood. Here, we quantified drought thresholds (T<sub>SM</sub>) from both surface soil moisture (SM<sub>surf</sub>) and SM<sub>root</sub> across contrasting lithologies to evaluate how geological settings modulates vegetation drought responses. We found pronounced spatial heterogeneity in T<sub>SM</sub>, with higher values in the peak forest plain (14.7th percentile) and basins, reflecting heightened atmospheric demand and greater drought vulnerability, whereas lower values in the karst plateau and gorge (10.3rd percentile) indicated stronger drought resistance. T<sub>SM</sub> exhibited a significant increasing trend during 2001–2018, implying a gradual decline in drought resistance. SM<sub>root</sub>-based thresholds (11.3rd percentile) were consistently lower than those derived from SM<sub>surf</sub> (12.9th percentile), highlighting the role of SM<sub>root</sub> in delaying the onset of drought stress. Karst ecosystems exhibited lower T<sub>SM</sub> than non-karst systems, especially in croplands and forests, indicating that vegetation in karst landscapes operates under drier conditions yet maintains higher drought tolerance. However, projections under future climate scenarios reveal greater drought risks in karst ecosystems, particularly under strong warming. Furthermore, climatic controls on T<sub>SM</sub> also differed between lithologies: in non-karst regions, thresholds responded coherently to plant-available water, whereas in karst regions, correlations with plant-available water alternated between positive and negative. This contrasting behavior suggests that karst vegetation flexibly shifts between shallow soil moisture and deeper bedrock water. These findings underscore the critical role of SM<sub>root</sub> in mitigating drought impacts and reveal that geological settings shape ecosystem drought resilience under changing climates.</div></div>\",\"PeriodicalId\":362,\"journal\":{\"name\":\"Journal of Hydrology\",\"volume\":\"663 \",\"pages\":\"Article 134216\"},\"PeriodicalIF\":6.3000,\"publicationDate\":\"2025-09-06\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Hydrology\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0022169425015549\",\"RegionNum\":1,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"ENGINEERING, CIVIL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Hydrology","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0022169425015549","RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, CIVIL","Score":null,"Total":0}
The role of root-zone soil moisture in delaying vegetation responses to drought: Comparative insights from karst and non-karst areas
Vegetation loss occurs when soil moisture falls below a critical threshold, above which vegetation can withstand drought stress. Root-zone soil moisture (SMroot) is crucial for enhancing drought resistance and sustaining ecosystem stability, yet its role in shaping drought thresholds and how these thresholds differ between karst and non-karst regions remains poorly understood. Here, we quantified drought thresholds (TSM) from both surface soil moisture (SMsurf) and SMroot across contrasting lithologies to evaluate how geological settings modulates vegetation drought responses. We found pronounced spatial heterogeneity in TSM, with higher values in the peak forest plain (14.7th percentile) and basins, reflecting heightened atmospheric demand and greater drought vulnerability, whereas lower values in the karst plateau and gorge (10.3rd percentile) indicated stronger drought resistance. TSM exhibited a significant increasing trend during 2001–2018, implying a gradual decline in drought resistance. SMroot-based thresholds (11.3rd percentile) were consistently lower than those derived from SMsurf (12.9th percentile), highlighting the role of SMroot in delaying the onset of drought stress. Karst ecosystems exhibited lower TSM than non-karst systems, especially in croplands and forests, indicating that vegetation in karst landscapes operates under drier conditions yet maintains higher drought tolerance. However, projections under future climate scenarios reveal greater drought risks in karst ecosystems, particularly under strong warming. Furthermore, climatic controls on TSM also differed between lithologies: in non-karst regions, thresholds responded coherently to plant-available water, whereas in karst regions, correlations with plant-available water alternated between positive and negative. This contrasting behavior suggests that karst vegetation flexibly shifts between shallow soil moisture and deeper bedrock water. These findings underscore the critical role of SMroot in mitigating drought impacts and reveal that geological settings shape ecosystem drought resilience under changing climates.
期刊介绍:
The Journal of Hydrology publishes original research papers and comprehensive reviews in all the subfields of the hydrological sciences including water based management and policy issues that impact on economics and society. These comprise, but are not limited to the physical, chemical, biogeochemical, stochastic and systems aspects of surface and groundwater hydrology, hydrometeorology and hydrogeology. Relevant topics incorporating the insights and methodologies of disciplines such as climatology, water resource systems, hydraulics, agrohydrology, geomorphology, soil science, instrumentation and remote sensing, civil and environmental engineering are included. Social science perspectives on hydrological problems such as resource and ecological economics, environmental sociology, psychology and behavioural science, management and policy analysis are also invited. Multi-and interdisciplinary analyses of hydrological problems are within scope. The science published in the Journal of Hydrology is relevant to catchment scales rather than exclusively to a local scale or site.