Title: Changes in wetland coverage in the Khurkh and Khuiten valleys of Mongolia based on Landsat 8 observations

Globally, wetlands have an essential role in biodiversity, ecosystems and human well-being. Wetlands include peatlands, swamps, marshes, lakes and rivers which provide essential ecosystem services (Ramsar Convention on Wetland 2018). However, worldwide, wetlands have been deteriorated constantly in the last several centuries. Effective ways to solve problems related to wetland management and monitoring include change detection of wetlands by using remote sensing. Remote sensing involves the process of acquiring information associated with an object, area and phenomenon from a distance. This study aimed to detect wetland changes in the Khurkh and Khuiten valleys of Mongolia, using Maximum Likelihood Classification and change detection methods. The classification method was based on ground truth data and applied to Landsat datasets with the Normalized Difference Water Index (NDWI), and Landsat 8 images for the years 2014, 2017 and 2019. The result of classification illustrated that open water increased by 0.1% from 2014 to 2017 and by 1.9% from 2017 to 2019. On the other hand, wetland classified areas decreased by 2.2% from 2014 to 2017, but increased by 4.7% from 2017 to 2019 because NDWI was sensitive to rainfall in 2019. According to change detection analysis, most conversions during the study years occurred from both wetland and open water to non-vegetated area. Most of these changes were dominant along the edge of the open water, along the edge of the wetland area and around the cropland area. Furthermore, one of the observed results was that conversion of vegetated area to non-vegetated area mostly occurred in high areas located close to the mountains.