Impacts of land-use change on carbon dynamics in China's coastal wetlands

Li-Shan Tan; Zhen-Ming Ge; Shi-Hua Li; Ke Zhou; Derrick Y F Lai; Stijn Temmerman; Zhi-Jun Dai

doi:10.1016/j.scitotenv.2023.164206

Impacts of land-use change on carbon dynamics in China's coastal wetlands

Sci Total Environ. 2023 Sep 10:890:164206. doi: 10.1016/j.scitotenv.2023.164206. Epub 2023 May 15.

Authors

Li-Shan Tan¹, Zhen-Ming Ge², Shi-Hua Li¹, Ke Zhou¹, Derrick Y F Lai³, Stijn Temmerman⁴, Zhi-Jun Dai¹

Affiliations

¹ State Key Laboratory of Estuarine and Coastal Research, Institute of Eco-Chongming, Center for Blue Carbon Science and Technology, East China Normal University, Shanghai, China.
² State Key Laboratory of Estuarine and Coastal Research, Institute of Eco-Chongming, Center for Blue Carbon Science and Technology, East China Normal University, Shanghai, China; Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station, Ministry of Education & Shanghai Science and Technology Committee, Shanghai, China. Electronic address: zmge@sklec.ecnu.edu.cn.
³ Department of Geography and Resource Management, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
⁴ Ecosphere Research Group, University of Antwerp, Antwerp, Belgium.

PMID: 37196957
DOI: 10.1016/j.scitotenv.2023.164206

Abstract

The impact of land-use and land-cover change (LULCC) on ecosystem carbon (C) dynamics has been previously documented at local and global scales, but uncertainty persists for coastal wetlands due to geographical variability and field data limitations. Field-based assessments of plant and soil C contents and stocks of various LULCC types were conducted in nine regions along the coastline of China (21°-40°N). These regions cover natural coastal wetlands (NWs, including salt marshes and mangroves) and former wetlands converted to different LULCC types, including reclaimed wetlands (RWs), dry farmlands (DFs), paddy fields (PFs) and aquaculture ponds (APs). The results showed that LULCC generally decreased the C contents and stocks of the plant-soil system by 29.6 % ± 2.5 % and 40.4 % ± 9.2 %, respectively, while it slightly increased the soil inorganic C contents and stocks. Wetlands converted to APs and RWs lost greater ecosystem organic C stocks (EOC, sum of plants and top 30 cm of soil organic C stocks) than other LULCC types. The annual potential CO₂ emissions estimated from EOC loss depended on the LULCC type, with an average emission of 7.92 ± 2.94 Mg CO₂-eq ha^-1 yr^-1. The change rate of EOC in all LULCC types showed a significantly deceasing trend with increasing latitude (p < 0.05). The loss of EOC due to LULCC was larger in mangroves than in salt marshes. The results showed that the response of plant and soil C variables to LULCC was mainly related to differences in plant biomass, median grain size, soil water content and soil NH₄⁺-N content. This study emphasized the importance of LULCC in triggering C loss in natural coastal wetlands, which strengthens the greenhouse effect. We suggest that the current land-based climate models and climate mitigation policies must account for specific land-use types and their associated land management practices to achieve more effective emission reduction.

Keywords: Greenhouse effect; Land-use change; Mangrove; Salt marsh; Soil carbon.

MeSH terms

Carbon / analysis
Carbon Dioxide
China
Ecosystem*
Soil
Wetlands*

Substances

Carbon
Carbon Dioxide
Soil