The state of the world’s mangroves in the 21st century under climate change
The state of the world's mangroves in the 21st century under climate change
Ilka C. Feller 0 1 2 3 4
0 D. A. Friess Department of Geography, National University of Singapore , 1 Arts Link , Singapore 117570 , Singapore
1 I. C. Feller (&) Smithsonian Institution, Smithsonian Environmental Research Center , 647 Contees Wharf Road, Edgewater, MD 21037 , USA
2 Guest editors: K. W. Krauss, I. C. Feller, D. A. Friess, R. R. Lewis III / Causes and Consequences of Mangrove Ecosystem Responses to an Ever-Changing Climate
3 R. R. Lewis III Lewis Environmental Services, Inc. , P.O. Box 5430, Salt Springs, FL 32134 , USA
4 K. W. Krauss U.S. Geological Survey, Wetland and Aquatic Research Center , 700 Cajundome Blvd., Lafayette, LA 70506 , USA
Concerted mangrove research and rehabilitation efforts over the last several decades have prompted a better understanding of the important ecosystem attributes worthy of protection and a better conservation ethic toward mangrove wetlands globally. While mangroves continue to be degraded and lost in specific regions, conservation initiatives, rehabilitation efforts, natural regeneration, and climate range expansion have promoted gains in other areas, ultimately serving to curb the high mangrove habitat loss statistics from the doom and gloom of the 1980s. We highlight those trends in this article and introduce this special issue of Hydrobiologia dedicated to the important and recurring Mangrove and Macrobenthos Meeting. This collection of papers represents studies presented at the fourth such meeting (MMM4) held in St. Augustine, Florida, USA, on July 18-22, 2016. Our intent is to provide a balanced message about the global state of mangrove wetlands by describing recent reductions in net mangrove area losses and highlighting primary research studies presented at MMM4 through a collection of papers. These papers serve not only to highlight on-going global research advancements, but also provide an overview of the vast amount of data on mangrove ecosystem ecology, biology and rehabilitation that emphasizes the uniqueness of the mangrove community.
Biology; Deforestation; Extent; Mangrove expansion; Restoration; Sea-level rise
Introduction
Tropical and sub-tropical mangrove forests are
considered a particularly important ecosystem for human
coastal communities due to their provision of
ecosystem services, such as timber and fuelwood
(Palacios &
Cantera, 2017)
, fisheries
(Benzeev et al., 2017;
Goecke & Carstenn, 2017)
, sediment trapping
(Kamal
et al., 2017)
, coastal defense
(Doughty et al., 2017;
Sheng & Zou, 2017)
, and carbon storage
(Donato
et al., 2011; Kelleway et al., 2016; Yando et al., 2016)
.
Nevertheless, mangrove forests are considered one of
the most threatened ecosystems across the tropics
(Duke et al., 2007). This is due in large part to
anthropogenic impacts on mangroves, including
conversion to aquaculture and agriculture, urbanization,
and pollution
(UNEP, 2014)
. As a transitional
intertidal ecosystem, mangrove forests are also considered
to be particularly vulnerable to climate change
stressors, such as sea-level rise
(Lovelock et al., 2015)
and
drought
(Duke et al., 2017)
, where changing
environmental conditions push mangroves beyond
speciesspecific thresholds of tolerance
(Ball, 1988)
.
Mangrove loss may not always be attributable to a single
driver like agriculture; instead, many natural and
anthropogenic stressors often interact additively or
synergistically, leading to rapid and large-scale
dieoffs in some locales, exemplified by recent (2016)
events in Australia
(Duke et al., 2017; Lovelock et al.,
2017a)
.
Whereas the general trend for mangroves across the
tropics and sub-tropics is one of decline, the broader
picture of the true state of the world’s mangroves is
more nuanced and complex. Huge efforts are being put
into mangrove rehabilitation and creation at landscape
scales. While such large-scale efforts are generally
unsuccessful due to poor species selection,
inappropriate choice of rehabilitation locations, and local
governance issues
(Lewis, 2005; Primavera &
Esteban, 2008; Elliott et al., 2016; Kodikara et al., 2017)
,
some efforts are becoming more successful as
elements of species biology and hydrological
requirements are incorporated into the design and
implementation of rehabilitation projects
(e.g., Matsui
et al., 2010; Oh et al., 2017)
. On a larger scale, climate
change may promote some positive gains, especially at
the northern and southern latitudinal limits of
mangroves, as mangroves encroach on and replace
saltmarsh species in some localities, which was a
major theme of the 4th Mangrove and Macrobenthos
Meeting (MMM4) held in St. Augustine, Florida in
2016.
The aim of this article is first to describe the MMM4
conference that was held in 2016 and its focus, and
then to assess the true state of the world’s mangroves
early in the 21st century, including some of the
potentially positive messages discussed du (...truncated)