Guidelines for integrating ecological and biological engineering technologies for control of severe erosion in mountainous areas â A case study of the Xiaojiang River Basin, China

Ecological environment issues caused by soil erosion have always been the attractive and significant problems all over the world. Under the background of global warming, debris flow, landslide, and other intense gravitational erosion activities have become aggravated, which leads to the decrease of biological diversity, ecosystem stability, resistance, productivity, and the like, which presents new challenges to traditional measures of soil and water conservation. This article, based on research conducted on controlling mountain hazard on the Xiaojiang River basin over the last 30 years, summarizes the managerial achievement of typical ecological engineering technologies and analyzes the principles and application of each type of treatment. The results indicated that established ecological engineering technologies play a significant role in the prevention and treatment of intense gravitational erosion caused by mountain hazard. However, there are still a great deal of limitation of application condition and maneuverability during management process. How to furtherly develop the rational combining pattern between ecological engineering (e.g. contour hedgerow) and geotechnical engineering (e.g. slit dam) and how to strengthen the risk control and improve management strategy will be the key points for preventing intense gravitational erosion in future by ecological engineering. Keywords: Soil and water conservation, Ecological engineering, Gravitational erosion, Risk control, Mountain hazard

Land Use Changes and Their Driving Forces in a Debris Flow Active Area of Gansu Province, China

Land use change is extremely sensitive to natural factors and human influence in active debris flow. It is therefore necessary to determine the factors that influence land use change. This paper took Wudu District, Gansu Province, China as a study area, and a systemic analysis of the transformational extent and rate of debris flow waste-shoal land (DFWSL) was carried out from 2005 to 2015. The results show that from 2005 to 2015, cultivated land resources transformed to other types of land; cultivated lands mainly transformed to grassland from 2005 to 2010 and construction land from 2010 to 2015. Moreover, the growth rate of construction land from 2005 to 2010 was only 0.11%, but increased to 6.87% between 2010 and 2015. The latter is more than 60 times the former. This increase was brought about by natural disasters (debris flow, earthquakes, and landslides) and anthropogenic factors (national policies or strategies), which acted as driving forces in debris flow area. The former determines the initial use type of the DFWSL while the latter only affects the direction of land use and transformation

Ecosystem sensitivity and landscape vulnerability of debris flow waste-shoal land under development and utilization changes

Debris flow waste-shoal land (DFWSL) is a new type of ecosystem in ecologically fragile areas of debris flows that is extremely sensitive to natural and anthropogenic disturbances. Existing studies have focused on the availability and utilization of DFWSL and impact analysis of DFWSL use with external environmental changes but have neglected to evaluate the vulnerability and sensitivity of the DFWSL system itself. To gain a more in-depth understanding of the sensitivity and vulnerability of the DFWSL system and the spatial relationship between them. In this study, a comprehensive and general methodology was developed to quantitatively illustrate the spatiotemporal changes of sensitivity and vulnerability of DFWSL and explore the spatially heterogeneous relationships between these relations and several socio-ecological drivers, integrating land transfer matrix, global Moran’s I and local Moran’s I, geographical detector, and multi-scale geographically weighted regression (MGWR) methods. Results show that the main land use types in the DFWSL, from 2014 to 2022, were cultivated and construction land. During that period, the area of cultivated land and water area decreased by 24.3% and 49.36%, respectively, while the area of forest land and construction land increased by 42.29% and 31.71%, respectively. Overall system sensitivity decreased during this period. The severe sensitive (Mid-High and High) area gradually decreased to the periphery areas and river basin outflows. The mild sensitive area increased (81% in 2014, 83% in 2018, and 90% in 2020) and was mainly located in the central area, mainly affected by elevation, rainfall, slope, and NDVImax. Landscape vulnerability (fragmentation) was mainly present in the central area, which was dominated by human activity (cultivated and construction land). The distributions of landscape vulnerability and sensitivity displayed a non-correspondence spatial correlation. This study improved our understanding of the spatial distribution characteristics of vulnerability and sensitivity of DFWSL and provided a basis for devising solutions to problems associated with disaster reduction and development