A database of global wetland validation samples for wetland mapping

Abstract

© 2015, Science China Press and Springer-Verlag Berlin Heidelberg. A database of global wetland validation samples (GWVS) is the foundation for wetland mapping on a global scale. In this work, a database of GWVS was created based on 25 “wetland-related” keyword searches of a total of 3,506 full-text documents downloaded from the Web of Science. Eight hundred and three samples from a total of 68 countries and 141 protected areas were recorded by the GWVS, including samples of marine/coastal wetlands, inland wetlands and human-made wetlands, at ratios of 53 %, 41 % and 6 %, respectively. The results exhibit spatial distribution among Terrestrial Ecoregions of the World, the World Database on Protected Areas and the Database of Global Administrative Areas. Within most of the biomes, protected areas and countries examined, the very low concentration of samples requires more attention in the future. The greatest concentration of samples within a single biome is found in the tropical and subtropical moist broadleaf forest biome, accounting for 27 % of the total samples, while no sample is found in the biome of tropical and subtropical coniferous woodland. Greater efforts are expected to be made to record samples in Oceania, Central Europe, Northern Europe, Northern Africa, Central Africa, Central America, the Caribbean, and midwestern South America. Our data show that it is feasible to map global wetlands using Landsat TM/ETM+ at 30-m resolution. The continued improvement of the GWVS sharing platform should be reinforced in the future, making a strong contribution to global wetland mapping and monitoring.