An Assessment of Vegetation Changes in the Three-River Headwaters Region, China: Integrating NDVI and Its Spatial Heterogeneity

Assessing vegetation changes in alpine arid and fragile ecosystems is imperative for informed ecological restoration initiatives and adaptive ecosystem management. Previous studies primarily employed the Normalized Difference Vegetation Index (NDVI) to reveal vegetation dynamics, ignoring the spatia...

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Main Authors: Xuejie Mou, Huixia Chai, Cheng Duan, Yao Feng, Xiahui Wang
Format: Article
Language:English
Published: MDPI AG 2024-10-01
Series:Plants
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Online Access:https://www.mdpi.com/2223-7747/13/19/2814
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author Xuejie Mou
Huixia Chai
Cheng Duan
Yao Feng
Xiahui Wang
author_facet Xuejie Mou
Huixia Chai
Cheng Duan
Yao Feng
Xiahui Wang
author_sort Xuejie Mou
collection DOAJ
description Assessing vegetation changes in alpine arid and fragile ecosystems is imperative for informed ecological restoration initiatives and adaptive ecosystem management. Previous studies primarily employed the Normalized Difference Vegetation Index (NDVI) to reveal vegetation dynamics, ignoring the spatial heterogeneity alterations caused by bare soil. In this study, we used a comprehensive analysis of NDVI and its spatial heterogeneity to examine the vegetation changes across the Three-River Headwaters Region (TRHR) over the past two decades. A random forest model was used to elucidate the underlying causes of these changes. We found that between 2000 and 2022, 9.4% of the regions exhibited significant changes in both NDVI and its spatial heterogeneity. These regions were categorized into six distinct types of vegetation change: improving conditions (62.1%), regrowing conditions (11.0%), slight degradation (16.2%), medium degradation (8.4%), severe degradation (2.0%), and desertification (0.3%). In comparison with steppe regions, meadows showed a greater proportion of improved conditions and medium degradation, whereas steppes had more instances of regrowth and slight degradation. Climate variables are the dominant factors that caused vegetation changes, with contributions to NDVI and spatial heterogeneity reaching 68.9% and 73.2%, respectively. Temperature is the primary driver of vegetation dynamics across the different types of change, with a more pronounced impact in meadows. In severely degraded steppe and meadow regions, grazing intensity emerged as the predominant driver of NDVI change, with an importance value exceeding 0.50. Notably, as degradation progressed from slight to severe, the significance of this factor correspondingly increased. Our findings can provide effective information for guiding the implementation of ecological restoration projects and the sustainable management of alpine arid ecosystems.
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spelling doaj-art-3ec80d214ebb42748be605e7aad4ba1a2025-08-20T01:47:37ZengMDPI AGPlants2223-77472024-10-011319281410.3390/plants13192814An Assessment of Vegetation Changes in the Three-River Headwaters Region, China: Integrating NDVI and Its Spatial HeterogeneityXuejie Mou0Huixia Chai1Cheng Duan2Yao Feng3Xiahui Wang4Institute of Ecological Protection and Restoration Planning/Yellow River Ecology and Environment Protection Center, Chinese Academy of Environmental Planning, Beijing 100041, ChinaInstitute of Ecological Protection and Restoration Planning/Yellow River Ecology and Environment Protection Center, Chinese Academy of Environmental Planning, Beijing 100041, ChinaInstitute of Ecological Protection and Restoration Planning/Yellow River Ecology and Environment Protection Center, Chinese Academy of Environmental Planning, Beijing 100041, ChinaKey Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, ChinaInstitute of Ecological Protection and Restoration Planning/Yellow River Ecology and Environment Protection Center, Chinese Academy of Environmental Planning, Beijing 100041, ChinaAssessing vegetation changes in alpine arid and fragile ecosystems is imperative for informed ecological restoration initiatives and adaptive ecosystem management. Previous studies primarily employed the Normalized Difference Vegetation Index (NDVI) to reveal vegetation dynamics, ignoring the spatial heterogeneity alterations caused by bare soil. In this study, we used a comprehensive analysis of NDVI and its spatial heterogeneity to examine the vegetation changes across the Three-River Headwaters Region (TRHR) over the past two decades. A random forest model was used to elucidate the underlying causes of these changes. We found that between 2000 and 2022, 9.4% of the regions exhibited significant changes in both NDVI and its spatial heterogeneity. These regions were categorized into six distinct types of vegetation change: improving conditions (62.1%), regrowing conditions (11.0%), slight degradation (16.2%), medium degradation (8.4%), severe degradation (2.0%), and desertification (0.3%). In comparison with steppe regions, meadows showed a greater proportion of improved conditions and medium degradation, whereas steppes had more instances of regrowth and slight degradation. Climate variables are the dominant factors that caused vegetation changes, with contributions to NDVI and spatial heterogeneity reaching 68.9% and 73.2%, respectively. Temperature is the primary driver of vegetation dynamics across the different types of change, with a more pronounced impact in meadows. In severely degraded steppe and meadow regions, grazing intensity emerged as the predominant driver of NDVI change, with an importance value exceeding 0.50. Notably, as degradation progressed from slight to severe, the significance of this factor correspondingly increased. Our findings can provide effective information for guiding the implementation of ecological restoration projects and the sustainable management of alpine arid ecosystems.https://www.mdpi.com/2223-7747/13/19/2814spatial heterogeneitydriving factorsrandom forestThree-River Headwaters Region
spellingShingle Xuejie Mou
Huixia Chai
Cheng Duan
Yao Feng
Xiahui Wang
An Assessment of Vegetation Changes in the Three-River Headwaters Region, China: Integrating NDVI and Its Spatial Heterogeneity
Plants
spatial heterogeneity
driving factors
random forest
Three-River Headwaters Region
title An Assessment of Vegetation Changes in the Three-River Headwaters Region, China: Integrating NDVI and Its Spatial Heterogeneity
title_full An Assessment of Vegetation Changes in the Three-River Headwaters Region, China: Integrating NDVI and Its Spatial Heterogeneity
title_fullStr An Assessment of Vegetation Changes in the Three-River Headwaters Region, China: Integrating NDVI and Its Spatial Heterogeneity
title_full_unstemmed An Assessment of Vegetation Changes in the Three-River Headwaters Region, China: Integrating NDVI and Its Spatial Heterogeneity
title_short An Assessment of Vegetation Changes in the Three-River Headwaters Region, China: Integrating NDVI and Its Spatial Heterogeneity
title_sort assessment of vegetation changes in the three river headwaters region china integrating ndvi and its spatial heterogeneity
topic spatial heterogeneity
driving factors
random forest
Three-River Headwaters Region
url https://www.mdpi.com/2223-7747/13/19/2814
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