Marine and Freshwater Research Marine and Freshwater Research Society
Advances in the aquatic sciences
RESEARCH ARTICLE

Global extent and distribution of wetlands: trends and issues

N. C. Davidson A B D , E. Fluet-Chouinard C and C. M. Finlayson A
+ Author Affiliations
- Author Affiliations

A Institute for Land, Water and Society, Charles Sturt University, Elizabeth Mitchell Drive, PO Box 789, Albury, NSW 2640, Australia.

B Nick Davidson Environmental, Queens House, Ford Street, Wigmore, HR6 9UN, UK.

C Hasler Laboratory of Limnology, University of Wisconsin—Madison, 680 N. Park Street, Madison, WI 53706, USA

D Corresponding author. Email: arenaria.interpres@gmail.com

Marine and Freshwater Research - https://doi.org/10.1071/MF17019
Submitted: 26 January 2017  Accepted: 16 September 2017   Published online: 10 January 2018

Abstract

Herein we review estimates of global and regional wetland area from ‘bottom-up’ approaches of site or national wetland inventories and ‘top-down’ approaches from global mapping and remote sensing. The trend for increasing wetland extent reported in the literature over time is a consequence of improved mapping technologies and methods rather than a real increase in wetland area, because a continuing trend for natural wetland loss and conversion is documented over the same time period. The most recent high-resolution estimate of global wetland area is in excess of 12.1 × 106 km2, of which 54% is permanently inundated and 46% is temporarily inundated. Globally, 92.8% of continental wetland area is inland and only 7.2% is coastal. Regionally, the largest wetland areas are in Asia (31.8%), North America (27.1%) and Latin America and the Caribbean (Neotropics; 15.8%), with smaller areas in Europe (12.5%), Africa (9.9%) and Oceania (2.9%). It is likely that estimates of global wetland area published to date persist in underestimating the true wetland area. The ‘grand challenge’ of a global inventory integrating all types of permanent and temporary wetlands at high spatial resolution has yet to be fully achieved.

Additional keywords: inventory, Ramsar Convention, remote sensing, wetland area.


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