Science - USA (2020-06-05)

sciencemag.org SCIENCE

PHOTO: JURGEN FREUND/MINDEN PICTURES

By Catherine E. Lovelock

W

hen knowledge of a system is im-

perfect, thresholds are extremely

useful tools for decision-makers.

Sea level rise (SLR) threatens in-

tertidal coastal wetlands because

these aquatic plants will drown

as water depths exceed their physiological

tolerance limits. For mangroves—trees and

shrubs that grow in tidal waters of the trop-

ics or subtropics—the threshold for SLR

has been elusive. On page 1118 of this issue,

Saintilan et al. ( 1 ) deduce that the threshold

SLR for mangrove ecosystems is 6 to 7 mm/

year. This discovery can help inform deci-

sions on how to sustain mangroves, which

provide 200 million coastal people with es-

sential ecosystem services. These include

protection from intense storms and waves,

reduction in the impact of coastal flooding,

sequestering of carbon, improvement in wa-

ter quality, and preservation of biodiversity

and fisheries ( 2 ).

PERSPECTIVES

INSIGHTS

Coastal mangrove ecosystems must rise above sea level to survive

ECOLOGY

Blue carbon from the past forecasts the future

1050 5 JUNE 2020 • VOL 368 ISSUE 6495

Published by AAAS