Trends in normalized difference vegetation index time series in differently regulated cascade reservoirs in Wujiang catchment, China

Dam construction is economically and ecologically important for power generation and water capture. However, the effects of cascade dams with various regulation types (i.e., daily, weekly, seasonal, yearly) on vegetation coverage are still need to be clarified. In the current study, we investigated...

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Main Authors: Junjie Fu, Wei Wang, Peter D. Hunter, Wei Li, Junyao Sun
Format: Article
Language:English
Published: Elsevier 2023-02-01
Series:Ecological Indicators
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S1470160X22013048
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author Junjie Fu
Wei Wang
Peter D. Hunter
Wei Li
Junyao Sun
author_facet Junjie Fu
Wei Wang
Peter D. Hunter
Wei Li
Junyao Sun
author_sort Junjie Fu
collection DOAJ
description Dam construction is economically and ecologically important for power generation and water capture. However, the effects of cascade dams with various regulation types (i.e., daily, weekly, seasonal, yearly) on vegetation coverage are still need to be clarified. In the current study, we investigated the effects of dam construction on vegetation coverage and predicted the dynamic trends of vegetation at the sub-catchment (i.e., the catchment removing the overlapping catchment of the upstream reservoir) and buffer scale of each reservoir. MODIS Terra normalized difference vegetation index (NDVI) composites (MOD13Q1, 2000–2019) were used to study spatial and temporal changes in riparian vegetation coverage. At the sub-catchment scale, the long-term mean NDVI increased significantly from upstream to downstream from 2000 to 2019, and the NDVI mutation point (i.e., turning point) was consistent with the construction year of the corresponding dam. At the temporal scale, the vegetation trend predictions indicated a greater degree of degradation (23 %–61 %) than in the past (2000–2019; 3 %–32 %). Our findings also showed that reservoir vegetation degradation was associated with regulation type, i.e., daily reservoirs experienced a higher degree of vegetation degradation. Each cascade reservoir exhibited higher past vegetation degradation within the 0–1 km buffer zone compared to the sub-catchment. However, future degradation was predicted to be much higher in the sub-catchment than in the 0–1 km buffer zone, indicating the potential impact of damming on vegetation from adjacent areas (i.e., 0–1 km buffer) with gradual expansion to more distant areas (i.e., sub-catchment) over time. A potential cascade effect of upstream dams on sub-catchment vegetation of downstream dams was also observed. This study provides a reference for watershed management and ecological civilization construction. Relevant laws and policies should be established in areas surrounding reservoirs to help mitigate dam-induced degradation of vegetation communities, especially in reservoirs with short retention times.
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spelling doaj.art-f7a7744d1760437bb5eaeec4b9a5b9252023-01-27T04:19:22ZengElsevierEcological Indicators1470-160X2023-02-01146109831Trends in normalized difference vegetation index time series in differently regulated cascade reservoirs in Wujiang catchment, ChinaJunjie Fu0Wei Wang1Peter D. Hunter2Wei Li3Junyao Sun4Aquatic Plants Research Center, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China; College of Science, Tibet University, Lhasa, Xizang 850000, China; School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, ChinaAquatic Plants Research Center, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China; Hubei Key Laboratory of Wetland Evolution & Ecological Restoration, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, ChinaBiological and Environmental Sciences, School of Natural Sciences, University of Stirling, Stirling FK9 4LA, United KingdomAquatic Plants Research Center, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China; College of Science, Tibet University, Lhasa, Xizang 850000, China; Hubei Key Laboratory of Wetland Evolution & Ecological Restoration, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, ChinaAquatic Plants Research Center, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China; Hubei Key Laboratory of Wetland Evolution & Ecological Restoration, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China; Corresponding author.Dam construction is economically and ecologically important for power generation and water capture. However, the effects of cascade dams with various regulation types (i.e., daily, weekly, seasonal, yearly) on vegetation coverage are still need to be clarified. In the current study, we investigated the effects of dam construction on vegetation coverage and predicted the dynamic trends of vegetation at the sub-catchment (i.e., the catchment removing the overlapping catchment of the upstream reservoir) and buffer scale of each reservoir. MODIS Terra normalized difference vegetation index (NDVI) composites (MOD13Q1, 2000–2019) were used to study spatial and temporal changes in riparian vegetation coverage. At the sub-catchment scale, the long-term mean NDVI increased significantly from upstream to downstream from 2000 to 2019, and the NDVI mutation point (i.e., turning point) was consistent with the construction year of the corresponding dam. At the temporal scale, the vegetation trend predictions indicated a greater degree of degradation (23 %–61 %) than in the past (2000–2019; 3 %–32 %). Our findings also showed that reservoir vegetation degradation was associated with regulation type, i.e., daily reservoirs experienced a higher degree of vegetation degradation. Each cascade reservoir exhibited higher past vegetation degradation within the 0–1 km buffer zone compared to the sub-catchment. However, future degradation was predicted to be much higher in the sub-catchment than in the 0–1 km buffer zone, indicating the potential impact of damming on vegetation from adjacent areas (i.e., 0–1 km buffer) with gradual expansion to more distant areas (i.e., sub-catchment) over time. A potential cascade effect of upstream dams on sub-catchment vegetation of downstream dams was also observed. This study provides a reference for watershed management and ecological civilization construction. Relevant laws and policies should be established in areas surrounding reservoirs to help mitigate dam-induced degradation of vegetation communities, especially in reservoirs with short retention times.http://www.sciencedirect.com/science/article/pii/S1470160X22013048Cascade reservoirsNDVIHurst analysesSpatiotemporal variationVegetation communityMutation point
spellingShingle Junjie Fu
Wei Wang
Peter D. Hunter
Wei Li
Junyao Sun
Trends in normalized difference vegetation index time series in differently regulated cascade reservoirs in Wujiang catchment, China
Ecological Indicators
Cascade reservoirs
NDVI
Hurst analyses
Spatiotemporal variation
Vegetation community
Mutation point
title Trends in normalized difference vegetation index time series in differently regulated cascade reservoirs in Wujiang catchment, China
title_full Trends in normalized difference vegetation index time series in differently regulated cascade reservoirs in Wujiang catchment, China
title_fullStr Trends in normalized difference vegetation index time series in differently regulated cascade reservoirs in Wujiang catchment, China
title_full_unstemmed Trends in normalized difference vegetation index time series in differently regulated cascade reservoirs in Wujiang catchment, China
title_short Trends in normalized difference vegetation index time series in differently regulated cascade reservoirs in Wujiang catchment, China
title_sort trends in normalized difference vegetation index time series in differently regulated cascade reservoirs in wujiang catchment china
topic Cascade reservoirs
NDVI
Hurst analyses
Spatiotemporal variation
Vegetation community
Mutation point
url http://www.sciencedirect.com/science/article/pii/S1470160X22013048
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