The prevailing idea that sea-level
rise will inevitably wipe out mangrove forests — fragile ecosystems that protect nearby communities from natural hazards such as floods and storms — is challenged by a recent report.
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Mangroves in some areas will be able
to survive climate change-induced
sea-level rise as they can slowly increase the level of soil in which they
thrive, but only if they are managed and protected, according to ‘The response
of mangrove soil surface elevation to sea level rise’ report.
Activities such as building dams on rivers and converting
mangrove areas into shrimp farms may have a stronger impact on the health of mangroves than sea-level rise, the
report adds. Once weakened by such changes, mangroves will be less able to
adapt to changes in sea level.
“A lot of the rivers [that feed
mangrove areas] are being dammed, and by doing that we reduce the freshwater
flow and sediment flow to mangroves. Both can be very deleterious for
mangroves,” says Anna McIvor, lead author of the report and a researcher
at the University of Cambridge, United Kingdom.
“Once mangroves are degraded,
they are much less likely to keep up with sea-level rise,” McIvor tells SciDev.Net.
The report surveyed key literature
published from 2006 to 2011, and found that mangroves in some areas have
adapted to rising sea levels and would continue to do so in the future.
But, it notes, longer-term data on
the effects of sea-level rise on mangroves are missing.
“Most of the current
measurements span [only] about ten years,” says McIvor. Yet, sea levels do
not rise that quickly.
She says that evidence is currently
also limited by the small number of locations in which mangrove studies have
taken place, restricting researchers’ abilities to assess differences in local
conditions and make global predictions on the future of mangroves.
Alfredo Quarto, executive director of
US conservation NGO the Mangrove Action Project, says that the report’s main
benefits are that it highlights the need for further study and the need to act.
“One of the problems with such
studies,” he says, “is that [though] they highlight things that are
important, how does one take those bits of information and put them into
practice to conserve the mangroves? So, I hope the report stimulates action by
governments and that they see the value of mangroves in protecting [communities].”
Read more at SciDevNet.
Mangrove image via Shutterstock.