Habitat degradation and quality assessment of Khyargas Lake, Western Mongolia and adjacent terrestrial and freshwater areas

Lakes in Western Mongolia have international significance as they provide an important stopover for numerous migratory bird species. These wetlands also have a primary role in acting as an ecological regulator for maintaining water regimes and habitats which directly impact the level of biodiversity, ecological functionality and climate change resilience of the surrounding environments. This study evaluates the habitat quality and degradation status over the period of 2002-2022 of Khyargas Lake, the second-largest brackish lake in Mongolia, and its terrestrial and interconnected freshwater surroundings, using the InVEST (Integrated valuation of ecosystem services and trade-offs) model. We used satellite images to analyse land cover changes and threat sources, estimating their maximum distance of impact and sensitivity score for each threat source within land cover types. The results indicate that steppe and dry steppe regions are transitioning toward semi-desert conditions, suggesting that the area may be experiencing aridification. By 2022, an estimated 11.1 % of the total study area was identified as exhibiting varying degrees of habitat degradation. We identified a particular risk of habitat quality losses around Khyargas Lake, where most tourism activities are present, and in areas with dry steppe and desert steppe land cover. Identifying areas of varying habitat quality and determining threats can help shape guide conservation and restoration efforts at Khyargas Lake more effectively. This may assist decision-makers in reducing the potential impact of human activities on habitat quality.