Tracking Historical Wetland Changes in the China Side of the Amur River Basin Based on Landsat Imagery and Training Samples Migration

Qiande Zhu,Yining Wang,Mingming Jia,Xuechun Li,Jinxia Liu,Hairong Pan

doi:10.3390/rs13112161

Abstract

In the recent decades, development of agricultural and human settlements have severely affected wetlands on the China-side of the Amur River Basin (CARB). A long-term holistic view of spatio-temporal variations of the wetlands on the CARB is essential for supporting sustainable conservation of wetlands in this region. In this study, a training sample migration method along with Random Forest classifier were adopted to map wetland and other land covers from two key seasons image collections. The proposed classification method was applied to Landsat images, and a 30-m resolution dataset was obtained, which reflected the dynamic changes of historical wetland distribution on the CARB region from 1990 to 2010. As the accuracy assessments showed, land cover maps of the CARB had high accuracies. The classification results indicated that the wetland area decreased from 89,432 km2 to 75,061 km2 between 1990 and 2010, with a net loss of 16%, which was mainly converted to paddy field and dry farmland, and the changes were most obvious in Sanjiang Plain and Songnen Plain. This suggests that agricultural activities are the main cause of wetland loss. The results can provide reliable information for the research on wetland management and sustainable development of the society and economy in the CARB.

Highlights

Wetlands, known as the kidneys of the Earth, cover approximately 6% of the terrestrial area and provide numerous ecosystem services, such as maintaining water balance, sequestrating carbon, regulating climate, and providing habitat [1,2]
The user’s accuracies (UA) and producer’s accuracies (PA) of the wetland category ranged from 82% ± 0.01 to 89% ± 0.001, while the two indices of other land cover types ranged from 62% ± 0.001 to 94% ± 0.002
A 30-m resolution dataset for the China-side of the Amur River Basin (CARB) containing historical spatial distribution information of wetlands and other land covers in 1990, 2000, and 2010 was produced

Summary

Introduction

Known as the kidneys of the Earth, cover approximately 6% of the terrestrial area and provide numerous ecosystem services, such as maintaining water balance, sequestrating carbon, regulating climate, and providing habitat [1,2]. Since the eighteenth century, up to 87% of wetlands have been lost globally, and severe degradation has happened in Asia as well as many high- and mid-latitude regions [3,4]. The Amur River Basin, spans Russia, China, and Mongolia, and is one of the world’s top ten largest river basins [5]. The wetlands in it provide abundant breeding habitats for migratory waterfowl on the East Asia–Australasia Flyway (EAAF) [4]. Compared with Europe and North America at the same latitudes, this basin has a unique landscape pattern [6] but less focus.

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