Tree mortality provides early warning sign of ecosystem functional transition in coastal freshwater forested wetlands
Abstract Globally, coastal forested wetlands are increasingly affected by relative sea level rise. However, the mechanisms underlying coastal wetland degradation remain unclear. Using the eddy covariance approach, we evaluated the long-term (i.e. 2009–2019) net ecosystem exchange (NEE), associated hydrology, and ecosystem structural changes in a forested wetland in North Carolina, USA. We quantified tree mortality in response to changes in hydrology. The ecosystem shifted from a net C sink (NEE = − 3.68 Mg C ha −1 yr −1 ) pre-2010 to a net C source (NEE = 0.87 Mg C ha −1 yr −1– 7.59 Mg C ha −1 yr −1 ) afterward. We ascribe the ecosystem C loss to increasing tree mortality (i.e. from 1.6% in 2009 to 45.8% in 2019), partly due to relative sea level rise ( R 2 = 0.62). Tree mortality, and consequent shift of NEE, provide early warning signs of a transition in this ecosystem more than 20 km inland from the coast.
Authors
- Kevan J. Minick (ORCID: https://orcid.org/0000-0002-1420-9580)
- Bhaskar Mitra (ORCID: https://orcid.org/0000-0002-6617-0884)
- John S. King (ORCID: https://orcid.org/0000-0002-9345-9800)
- Xinxueqi Han
- Katie Brannum
- Maricar M. Aguilos (ORCID: https://orcid.org/0000-0002-1949-3736)
- Ge Sun (ORCID: https://orcid.org/0000-0002-0159-1370)
- Asko Noormets (ORCID: https://orcid.org/0000-0003-2221-2111)
- Benju Baniya (ORCID: https://orcid.org/0000-0002-0111-9543)
- John Oliver Watts
- Prajaya Prajapati (ORCID: https://orcid.org/0000-0002-8209-6282)
- Steven G. McNulty (ORCID: https://orcid.org/0000-0003-4518-5646)
- Merry Shi
- Ning Liu (ORCID: https://orcid.org/0000-0003-0956-3208)
- James R. Webb
- M. A. Whitley
- Cameron Carter
- Brandon Middlebrough
- James Bulluck
- Manaswini Ganjam (ORCID: https://orcid.org/0000-0002-6569-9073)
Institutions
- Commonwealth Scientific and Industrial Research Organisation (AU)
- North Carolina State University (US)
- James Hutton Institute (GB)
- Duke University (US)
- Dalian University of Technology (CN)
- Dalian University (CN)
- Southern Research Station (US)
- Campbell Scientific (Canada) (CA)
- China University of Petroleum, East China (CN)
- Texas A&M University (US)
Publication Details
- Journal
- Environmental Research Letters
- Published
- 2025-08-28
- DOI
- https://doi.org/10.1088/1748-9326/ae0057
- Primary Topic
- Coastal wetland ecosystem dynamics
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- U.S. Department of Energy
- U.S. Department of Agriculture
- National Institute of Food and Agriculture
- U.S. Forest Service
- Biological and Environmental Research
- Southern Research Station
- Lawrence Berkeley National Laboratory