Effectiveness of the Qilian Mountain Nature Reserve of China in Reducing Human Impacts

The environmental impact assessment of China's ecological migration from a social-ecological perspective

When accounting for the social-ecological impact of an ecological restoration program, both objective environmental contexts and people's subjective perceptions are required. While this kind of environmental impact assessment lacks a comprehensive perspective. We use the difference-in-differences model to evaluate the effect of the greenness of the landscape after ecological migration in the Qilian Mountains in China; and analysis of variance and fixed effects models are used to evaluate the effects of such ecological restoration programs on local people's perceptions. The results show that the ecological migration program in the Qilian Mountains has been successful at not only significantly improving remotely sensed greenness at the landscape scale, but also at enhancing immigrants' environmental perceptions. These findings demonstrate the environmental impacts of ecological migration from a social-ecological perspective, and can provide methodological implications for landscape planning to support a better understanding of ecological restoration programs in the drylands.

Homogenization of microplastics in alpine rivers: Analysis of microplastic abundance and characteristics in rivers of Qilian Mountain, China

Microplastics in remote areas has received increasing concern in recent years. However, studies on microplastics in alpine rivers and their affecting factors are still limited. In this study, we investigate the abundance and characteristics of microplastic in the surface water of five alpine rivers in Qilian Mountain, China. Utilizing sieve collection, digestion and density separation, along with microscopy and Raman spectroscopy analyses, microplastics were observed in all the water samples and the average abundance of microplastics was 0.48 ± 0.28 items/L, which was lower than in other freshwaters. Transparent (37.3%) and fibrous (72.1%) microplastics were predominant. Polypropylene (53.8%) was the most frequently identified polymer type. Analysis of similarities (ANOSIM) and linear discriminant analysis (LDA) based on microplastic shape, color, and polymer type showed that there was no significant difference in the microplastic characteristics among rivers of Qilian Mountain. The distance decay models revealed that the similarity in microplastics characteristics was not affected by changes in watershed characteristics, such as geographical distance, elevation, water quality, and land use. This finding suggests that the primary source of microplastics in Qilian Mountain rivers could be from dispersed origins. The results of this study indicated that despite remote alpine rivers suffering limited anthropogenic impacts, they were not immune to microplastics. However, in watersheds with lower intensity of human activity, the abundance and characteristics of microplastics in water bodies may be more uniformly distributed and controlled by diffusion conditions such as atmospheric transport or riverine transport. Our investigation unveils novel understanding of microplastic dispersion in secluded alpine territories, emphasizing the crucial need for managing atmospheric transport of microplastics within conservation areas.

Evaluation and prediction of ecological carrying capacity in the Qilian Mountain National Park, China

With increasing human impacts on the ecosystem in natural protected areas, there is an urgent need to undertake an assessment of ecological carrying capacity taken as a benchmark for assessing regional sustainability. Based on satellite remote sensing and socio-economic statistical data from 2000 to 2019, this study distinguished the controlling factors for the spatial and temporal patterns of ecological carrying capacity in the Qilian Mountain National Park, one of the 10 pilot national parks in China. The ecological carrying capacity index (ECCI) was developed by using the Driver-Pressure-State-Impact-Response framework and a comprehensive weight method. The results showed that the multiyear averaged ECCI was low in the south and west but was high in central and eastern regions. The spatial distribution of the ECCI was constrained by soil resources, ecosystem quality, land use/cover and water environment. At the regional scale, the ECCI decreased from 2000 to 2014, especially in Tianzhu, where farmland expansion and severe droughts reduced habitat quality and ecosystem function. However, the ECCI increased significantly from 2014 to 2019, which was attributed to a warm moist climate and the implementation of eco-environmental protection policies. Forest and grassland coverage, soil and water conservation, waste water treatment amount and terrestrial water reserves accounted for 35%, 26%, 20% and 8%, respectively, of the temporal variability in the ECCI. Concurrent with national park development, the ECCI is predicted to increase in most areas from 2020 to 2029 by back-propagation artificial neural networks, except for Sunan, Shandan and Menyuan, possibly owing to increasing conflicts between humans and the environment. The findings of this study provide evidence about the effectiveness of government policies in promoting regional sustainability by altering ecosystem composition and function. In addition, the dominant drivers for the temporal variability of ecological carrying capacity varied in space according to stepwise regression analysis, calling for region-specific management strategies in mountain protected areas and their surroundings.