A World Without Mangroves?

Study Number:

5

Author:

N.C. Duke, J.-O. Meynecke, S. Dittmann, A. M. Ellison, K. Anger, U. Berger, S. Cannicci, K. Diele, K. C. Ewel, C. D. Field, N. Koedam, S. Y. Lee, C. Marchand, I. Nordhaus & F. Dahdouh-Guebas

Abstract:

“At a meeting of world mangrove experts held last year in Australia, it was unanimously agreed that we face the prospect of a world deprived of the services offered by mangrove ecosystems, perhaps within the next 100 years.”

Main Results and Conclusions:

• The global mangrove extinction rate is considered to be 1-2%, with certain forests already facing permanent extinction:

• “Mangrove forests once covered more than 200,000 km2 of sheltered tropical and subtropical coastlines (Centre for Marine Studies). They are disappearing worldwide by 1 to 2% per year, a rate greater than or equal to declines in adjacent coral reefs or tropical rainforests (Australian Rivers Institute and School of Environment; School of Biological Sciences; Harvard University; Alfred-Wegener-Institut für Polar- und Meeresforschung)” (41).
• “Mangroves are already critically endangered or approaching extinction in 26 out of the 120 countries having mangroves (Australian Rivers Institute and School of Environment; U.S. Department of Agriculture Forest Service)” (41).

• Species richness and ecosystem health declines with a direct correlation to forest degradation: “Where mangrove forests are cleared for aquaculture, urbanization, or coastal landfill or deteriorate due to indirect effects of pollution and upstream land use (coastal development) (School of Biological Sciences; Harvard University), their species richness is expected to decline precipitously, because the number of mangrove plant species is directly correlated with forest size (Technical University Dresden; Dipartimento di Biologia Animale e Genetica)” (41).
• Deforestation decreases the availability of ecosystem services that are naturally provided by mangrove forests: “Deforestation of mangrove forests, which have extraordinarily high rates of primary productivity (3), reduces their dual capacity to be both an atmospheric CO2 sink (Faculty of Science (Gore Hill)) and an essential source of oceanic carbon”(41). The decline further imperils mangrove-dependent fauna with their complex habitat linkages, as well as physical benefits like the buffering of seagrass beds and coral reefs against the impacts of river-borne siltation, or protection of coastal communities from sea-level rise (climate change), storm surges, and tsunamis (LGPMC, EA 3325; Biocomplexity Research Focus). Human communities living in or near mangroves would lose access to sources of essential food, fibers, timber, chemicals, and medicines” (41).
   

Works Cited:

Centre for Marine Studies, University of Queensland, St Lucia, Qld 4072, Australia.

Australian Rivers Institute and School of Environment, PMB 50 GCMC, Griffith University, Qld 9726, Australia.

School of Biological Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia.

Harvard University, Harvard Forest, 324 North Main Street, Petersham, MA 01366, USA.

Alfred-Wegener-Institut für Polar- und Meeresforschung, Kurpromenade, D-27498 Helgoland, Germany.

Technical University Dresden, Institut fÜr Waldwachstum und Forstliche Informatik, Postfach 1117 01735 Tharandt, Germany.

Dipartimento di Biologia Animale e Genetica “Leo Pardi,” Università degli Studi di Firenze, Via Romana, 17, I-50125 Firenze, Italy.

U.S. Department of Agriculture Forest Service, 2126 NW 7th Lane, Gainesville, FL 32603, USA.

Faculty of Science (Gore Hill), University of Technology, Sydney, Post Office Box 123, Broadway NSW 2007, Australia.

LGPMC, EA 3325, University of New Caledonia, Noumea, New Caledonia, and UR 103, Institut de Recherche pour le Développement (IRD), Marseille, France.

Biocomplexity Research Focus, c/o Laboratory of General Botany and Nature Management, Mangrove Management Group, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium.