Short-term experimental flooding impacts soil biogeochemistry but not aboveground vegetation in a coastal forest

P Peter Regier (Marine and Coastal Research Laboratory, Pacific Northwest National Laboratory) B Ben Bond-Lamberty (Pacific Northwest National Laboratory) N Nicholas Ward (Marine and Coastal Research Laboratory, Pacific Northwest National Laboratory) V Vanessa Bailey (Pacific Northwest National Laboratory) R Roberta Bittencourt Peixoto (University of Toledo) F Fausto Machado-Silva (University of Toledo) N Nate McDowell K Kendalynn A. Morris (Pacific Northwest National Laboratory) A Allison Myers-Pigg (Marine and Coastal Research Laboratory, Pacific Northwest National Laboratory) S Stephanie C. Pennington (Pacific Northwest National Laboratory) M Mizanur Rahman (Pacific Northwest National Laboratory) R Roy Rich (Smithsonian Environmental Research Center) R Richard W. Smith (Global Aquatic Research LLC) S Stephanie J. Wilson (Smithsonian Environmental Research Center) S Stella C. Woodard (Global Aquatic Research LLC) A Alice Stearns (Smithsonian Environmental Research Center) D Donnie Day (University of Toledo) K Kennedy Doro (University of Toledo) E Efemena Emmanuel (University of Toledo) C Charlotte Grossiord (Pacific Northwest National Laboratory) A Anya Hopple (Smithsonian Environmental Research Center) O Olawale Ogunsola (University of Toledo) K Kaizad Patel (Pacific Northwest National Laboratory) E Evan Phillips (Smithsonian Environmental Research Center) J J. Patrick Megonigal (Smithsonian Environmental Research Center)

Abstract

Rising sea levels and intensifying storms increase flooding pressure on coastal forests, triggering tree mortality, ecosystem transitions, and changes to the coastal carbon cycle. However, the mechanisms that drive coastal forest mortality remain elusive due to the complex interplay between belowground and aboveground processes during flooding disturbances and limitations of observations typically reported in coastal forest mortality studies. We used an ecosystem-scale manipulation to simulate hurricane-level flooding of a coastal forest and explore the individual and interactive impacts of inundation and salinity. Monitoring real-time soil conditions and tree physiological responses, we observed consistent impacts on soil biogeochemistry aligned with belowground drivers of tree mortality, but no consistent responses in aboveground vegetation immediately following flooding. Our findings provide empirically based insight into the earliest stages of a hypothesized forest mortality spiral and offer critical benchmarks for predicting coastal forest resilience in the face of accelerating climate change.

Article Details

Volume / Issue Vol. 122, Issue 41
Published October 14, 2025
ISSN 0027-8424
Publisher National Academy of Sciences

Authors (25)

P

Peter Regier

Marine and Coastal Research Laboratory, Pacific Northwest National Laboratory

B

Ben Bond-Lamberty

Pacific Northwest National Laboratory

N

Nicholas Ward

Marine and Coastal Research Laboratory, Pacific Northwest National Laboratory

V

Vanessa Bailey

Pacific Northwest National Laboratory

R

Roberta Bittencourt Peixoto

University of Toledo

F

Fausto Machado-Silva

University of Toledo

N

Nate McDowell

K

Kendalynn A. Morris

Pacific Northwest National Laboratory

A

Allison Myers-Pigg

Marine and Coastal Research Laboratory, Pacific Northwest National Laboratory

S

Stephanie C. Pennington

Pacific Northwest National Laboratory

M

Mizanur Rahman

Pacific Northwest National Laboratory

R

Roy Rich

Smithsonian Environmental Research Center

R

Richard W. Smith

Global Aquatic Research LLC

S

Stephanie J. Wilson

Smithsonian Environmental Research Center

S

Stella C. Woodard

Global Aquatic Research LLC

A

Alice Stearns

Smithsonian Environmental Research Center

D

Donnie Day

University of Toledo

K

Kennedy Doro

University of Toledo

E

Efemena Emmanuel

University of Toledo

C

Charlotte Grossiord

Pacific Northwest National Laboratory

A

Anya Hopple

Smithsonian Environmental Research Center

O

Olawale Ogunsola

University of Toledo

K

Kaizad Patel

Pacific Northwest National Laboratory

E

Evan Phillips

Smithsonian Environmental Research Center

J

J. Patrick Megonigal

Smithsonian Environmental Research Center