Conversion of Natural Wetland to Farmland in the Tumen River Basin: Human and Environmental Factors

Yuyan Liu,Weihong Zhu,Ri Jin

doi:10.3390/rs13173498

Yuyan Liu, Weihong Zhu + Show 1 more

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https://doi.org/10.3390/rs13173498

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Abstract

Wetlands play an important role in the terrestrial ecosystem. However, agricultural activities have resulted in a significant decrease in natural wetlands around the world. In the Tumen River Basin (TRB), a border area between China, the Democratic People’s Republic of Korea (DPRK), and Russia, natural wetlands have been reclaimed and converted into farmland, primarily due to the migration practices of Korean-Chinese. To understand the spatial and temporal patterns of this conversion from wetlands to farmland, Landsat remote sensing images from four time periods were analyzed. Almost 30 years of data were extracted using the object-oriented classification method combined with random forest classification. In addition, statistical analysis was conducted on the conversion from natural wetland to farmland and from farmland to wetland, as well as on the relationship between the driving factors. The results revealed that a loss of 49.2% (12,540.1 ha) of natural wetlands in the Chinese portion of the TRB was due to agricultural encroachment for grain production. At the sub-basin scale, the largest area of natural wetland converted into farmland in the past 30 years was in the Hunchun River Basin (HCH), which accounts for 22.0% (2761.2 ha) of the total. Meanwhile, 6571.4 ha of natural wetlands, mainly in the Gaya River Basin (GYH), have been restored from farmland. These changes are closely related to the migration of the agricultural populations.

Highlights

The natural wetlands in the Chinese portion of the Tumen River Basin (TRB) were divided into four types, and farmland was divided into two types (Table 2) [25,28]
Natural wetlands and farmland are mainly distributed within the middle reaches of the TRB
At the sub-basin scale, natural wetlands are mainly distributed in GPG, HQH, BHH, GYH, and Hunchun River Basin (HCH), while farmland is mainly distributed in the middle and lower reaches of HLJ, the middle reaches of BHH, the middle reaches of GYH, and the upper reaches of HCH (Figure 3)

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Wetlands are widely distributed globally and are ecosystems rich in biodiversity and with high productivity [2]. They are a source of water for agricultural production [3] and offer excellent conditions for agricultural development [4]. They play a role in improving water quality, contributing to drought resistance, creating a humid climate, and promoting the development of biodiversity

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