title: Global wetlands: Potential distribution, wetland loss, and status.
abstract: Even though researchers have paid a great deal of attention to wetland loss and status, the actual extent of wetland loss on a global scale, especially the loss caused directly by human activities, and the actual extent of currently surviving wetlands remains uncertain. This paper simulated the potential distribution of global wetlands by employing a new Precipitation Topographic Wetness Index (PTWI) and global remote sensing training samples. The results show earth would have approximately 29.83millionkm2of wetlands, if humans did not interfere with wetland ecosystems. By combining datasets related to global wetlands, we found that at least 33% of global wetlands had been lost as of 2009, including 4.58millionkm2of non-water wetlands and 2.64millionkm2of open water. The areal extent of wetland loss has been greatest in Asia, but Europe has experienced the most serious losses. Wetland-related datasets suffer from major inconsistencies, and estimates of the areal extent of the remaining global wetlands ranged from 1.53 to 14.86millionkm2. Therefore, although it is challenging, thematic mapping of global wetlands is necessary and urgently needed.
authors.affiliation: State Key Laboratory of Remote Sensing Science, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Shengjie
authors.initials: S
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Remote Sensing Science, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100101, China. Electronic address: niuzg@radi.ac.cn.
authors.forename: Zhenguo
authors.initials: Z
authors.lastname: Niu
authors.affiliation: State Key Laboratory of Remote Sensing Science, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Yanfen
authors.initials: Y
authors.lastname: Chen
authors.affiliation: WWF International, Avenue du Mont-Blanc 27, 1196 Gland, Switzerland.
authors.forename: Lifeng
authors.initials: L
authors.lastname: Li
authors.affiliation: State Key Laboratory of Remote Sensing Science, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Haiying
authors.initials: H
authors.lastname: Zhang
keywords: Global remaining wetlands; Global wetland loss; Global wetland simulation; Wetland potential distribution