Dynamic changes and influential factors of blowouts in a desert artificial ecosystem at the southeastern margin of Tengger Desert in China.

Abstract

The wind-blown sand protection system in the Shapotou section of the Baotou-Lanzhou Railway is a representative artificial ecosystem in a desert region. Over the past 70 years, this system has transformed mobile dunes into fixed dunes through vegetation succession, relying solely on natural rainfall without additional irrigation. However, ecosystem sustainability has been endangered by the emergence of numerous blowouts. Therefore, understanding the status and developmental trends of these blowouts is crucial for maintaining the system and ensuring railway safety. In this study, we quantitatively analyzed the number, spatial pattern, and evolution process of blowouts using a landscape pattern index and Spatial-Temporal Analysis of Moving Polygons (STAMP) model with remote sensing images from 2009 to 2022. Currently, blowout areas account for 1.57% of the total area with a clustered distribution. The number of blowouts increased significantly from 308 to 463 between 2009 and 2022 and increased with increasing distance from the railway line. Various evolutionary events have occurred among the blowouts, with peak frequencies in the generation and disappearance events observed by 2022. The average growth rate of blowouts was 7.32% in areas with less than 40 years of sand fixation but less than 1% in areas with more than 40 years, and mid-sized blowouts predominated the overall protection system. There was little difference between the blowout wind-erosion area and the fixed area in the natural environment. However, human activities can accelerate the evolution of blowouts, leading to more frequent contraction and expansion events and significantly increasing the area of wind erosion.