Does Ecological Water Replenishment Help Prevent a Large Wetland from Further Deterioration? Results from the Zhalong Nature Reserve, China

Ecological water replenishment (EWR) has been increasingly applied to the restoration and maintenance of wetland hydrological conditions across China since the beginning of the 21st century. However, little is known about whether EWR projects help protect and/or restore wetland ecohydrology. As one...

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Main Authors: Liwen Chen, Sixin Liu, Yanfeng Wu, Y. Jun Xu, Shengbo Chen, Shiliang Pang, Zongting Gao, Guangxin Zhang
Format: Article
Language:English
Published: MDPI AG 2020-10-01
Series:Remote Sensing
Subjects:
Online Access:https://www.mdpi.com/2072-4292/12/20/3449
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author Liwen Chen
Sixin Liu
Yanfeng Wu
Y. Jun Xu
Shengbo Chen
Shiliang Pang
Zongting Gao
Guangxin Zhang
author_facet Liwen Chen
Sixin Liu
Yanfeng Wu
Y. Jun Xu
Shengbo Chen
Shiliang Pang
Zongting Gao
Guangxin Zhang
author_sort Liwen Chen
collection DOAJ
description Ecological water replenishment (EWR) has been increasingly applied to the restoration and maintenance of wetland hydrological conditions across China since the beginning of the 21st century. However, little is known about whether EWR projects help protect and/or restore wetland ecohydrology. As one of the earliest and longest-running EWR projects in China, water has been released from the Nenjiang River into the Zhalong wetland since 2001. It is important to examine the ecohydrological effects of this EWR project. In this study, long time series remote sensing data were used to extract the water area, inundation frequency, and normalized difference vegetation index (NDVI) to explore how eco-hydrological conditions changed during the pre- (1984–2000) and post-EWR (2001–2018) periods in the Zhalong wetland. Results show that the inundation area decreased due to the reduced surface water inflow during the pre-EWR period. Similarly, monthly vegetation NDVI in the growing season generally exhibited a decreasing and an increasing trend during the pre- and post-EWR periods, respectively. In the post-EWR period, NDVI increased by 19%, 73%, 45%, 28%, 13% for the months of May through September, respectively. Due to EWR, vegetation growth in areas with low inundation frequency was better than in areas with high inundation frequency. We found that the EWR project, runoff, and precipitation contributed 25%, 11%, and 64% to changes in the NDVI, respectively, and 46%, 37%, and 17% to changes in inundation area, respectively. These results indicate that the EWR project has improved hydrological conditions in the Zhalong wetland. For further maximum benefits of EWR in the Zhalong wetlands, we suggest that implementing similar eco-hydrological projects in the future should focus on flood pulse management to increase the inundation area, improve hydrological connectivity, and create new habitats.
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spelling doaj.art-0a75d7bead16493bba69a87806208e872023-11-20T17:49:18ZengMDPI AGRemote Sensing2072-42922020-10-011220344910.3390/rs12203449Does Ecological Water Replenishment Help Prevent a Large Wetland from Further Deterioration? Results from the Zhalong Nature Reserve, ChinaLiwen Chen0Sixin Liu1Yanfeng Wu2Y. Jun Xu3Shengbo Chen4Shiliang Pang5Zongting Gao6Guangxin Zhang7College of Geo-exploration Science and Technology, Jilin University, Changchun 130026, ChinaCollege of Geo-exploration Science and Technology, Jilin University, Changchun 130026, ChinaNortheast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, ChinaSchool of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USACollege of Geo-exploration Science and Technology, Jilin University, Changchun 130026, ChinaZhalong National Nature Reserve of Heilongjiang Province, Qiqihar 161006, ChinaJilin Provincial Key Laboratory of Changbai Mountain Meteorology & Climate Change, Changchun 130062, ChinaNortheast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, ChinaEcological water replenishment (EWR) has been increasingly applied to the restoration and maintenance of wetland hydrological conditions across China since the beginning of the 21st century. However, little is known about whether EWR projects help protect and/or restore wetland ecohydrology. As one of the earliest and longest-running EWR projects in China, water has been released from the Nenjiang River into the Zhalong wetland since 2001. It is important to examine the ecohydrological effects of this EWR project. In this study, long time series remote sensing data were used to extract the water area, inundation frequency, and normalized difference vegetation index (NDVI) to explore how eco-hydrological conditions changed during the pre- (1984–2000) and post-EWR (2001–2018) periods in the Zhalong wetland. Results show that the inundation area decreased due to the reduced surface water inflow during the pre-EWR period. Similarly, monthly vegetation NDVI in the growing season generally exhibited a decreasing and an increasing trend during the pre- and post-EWR periods, respectively. In the post-EWR period, NDVI increased by 19%, 73%, 45%, 28%, 13% for the months of May through September, respectively. Due to EWR, vegetation growth in areas with low inundation frequency was better than in areas with high inundation frequency. We found that the EWR project, runoff, and precipitation contributed 25%, 11%, and 64% to changes in the NDVI, respectively, and 46%, 37%, and 17% to changes in inundation area, respectively. These results indicate that the EWR project has improved hydrological conditions in the Zhalong wetland. For further maximum benefits of EWR in the Zhalong wetlands, we suggest that implementing similar eco-hydrological projects in the future should focus on flood pulse management to increase the inundation area, improve hydrological connectivity, and create new habitats.https://www.mdpi.com/2072-4292/12/20/3449eco-hydrological restorationecological water replenishmentwetland inundation frequencywetland NDVIremote sensingZhalong wetland
spellingShingle Liwen Chen
Sixin Liu
Yanfeng Wu
Y. Jun Xu
Shengbo Chen
Shiliang Pang
Zongting Gao
Guangxin Zhang
Does Ecological Water Replenishment Help Prevent a Large Wetland from Further Deterioration? Results from the Zhalong Nature Reserve, China
Remote Sensing
eco-hydrological restoration
ecological water replenishment
wetland inundation frequency
wetland NDVI
remote sensing
Zhalong wetland
title Does Ecological Water Replenishment Help Prevent a Large Wetland from Further Deterioration? Results from the Zhalong Nature Reserve, China
title_full Does Ecological Water Replenishment Help Prevent a Large Wetland from Further Deterioration? Results from the Zhalong Nature Reserve, China
title_fullStr Does Ecological Water Replenishment Help Prevent a Large Wetland from Further Deterioration? Results from the Zhalong Nature Reserve, China
title_full_unstemmed Does Ecological Water Replenishment Help Prevent a Large Wetland from Further Deterioration? Results from the Zhalong Nature Reserve, China
title_short Does Ecological Water Replenishment Help Prevent a Large Wetland from Further Deterioration? Results from the Zhalong Nature Reserve, China
title_sort does ecological water replenishment help prevent a large wetland from further deterioration results from the zhalong nature reserve china
topic eco-hydrological restoration
ecological water replenishment
wetland inundation frequency
wetland NDVI
remote sensing
Zhalong wetland
url https://www.mdpi.com/2072-4292/12/20/3449
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