Land Use Change and Landscape Ecological Risk Assessment Based on Terrain Gradients in Yuanmou Basin

Abstract

Investigating the distribution characteristics of landscape ecological risk (LER) on terrain gradients is of great significance for optimizing the landscape pattern of ecologically vulnerable areas in mountainous regions and maintaining the sustainable development of the ecological environment. The Yuanmou Basin is a typical ecologically vulnerable area in the southwestern mountainous region of China, where issues such as soil erosion are pronounced, becoming one of the main factors restricting regional economic development. This study selected the Yuanmou Basin as the study area, and, using land use data from 2000, 2010, and 2020, constructed an LER assessment model based on disturbance and vulnerability. By integrating elevation and topographic position index data, we examined the spatiotemporal evolution characteristics of LER under different terrain gradients. The LER assessment results are summarized as follows: (1) From 2000 to 2020, the land use types of the Yuanmou Basin were mainly grassland, forest land and cropland. The land use showed a sharp increase in the cropland area and a simultaneous decrease in the grassland area, indicating a main land use evolution direction from grassland to cropland. (2) Over the span of 20 years, the average landscape ecological risk in the Yuanmou Basin slightly increased, specifically manifesting as a significant reduction in low ecological risk areas, while areas of medium and slightly lower ecological risks saw an increase. (3) The spatial distribution of LER in the Yuanmou Basin presents a pattern of being low on the periphery and high in the center, with significant positive spatial correlation, obvious spatial aggregation, as well as “high-high” and “low-low” clustering. (4) Low- and lower-risk areas in the Yuanmou Basin are distributed in the non-arid thermal zone and the medium–high terrain zone, while areas of medium, higher and high risk levels are mainly distributed in the arid thermal zone and the low terrain zone. The research results provide a scientific basis for optimizing and developing the land resources of the Yuanmou Basin.

Study on Spatial and Temporal Changes in Landscape Ecological Risks and Indicator Weights: A Case Study of the Bailong River Basin

“…As seen in Figure 6, according to the division of secondary land types, there are 22 secondary land types in the BRB, among which forest land (21)(22)(23)(24) has the largest area: more than 1/3 of the total area of the basin. Generally speaking, there has been little change in land use types in the past two decades, with Gobi (62) belonging to the disappeared land types and marshes (64) being a site type that increases first and disappears last.…”

“…The overall LER of the BRB is characterized by an increase in lower-risk zones and a decrease in medium-risk zones, as shown in Figure 9. In 2000, the lower-risk zone was dominated by forest land (21,22) and water bodies (42), with forest land dominated by natural forest land and artificial forest land (21) and shrubland (22), and water bodies dominated by lakes (42). By 2010, some grasslands (31,32,33), built-up land (52,53), and unused land (64,65,67) were added as lower-risk areas, further increasing the size of the lower-risk areas.…”

“…By 2020, the area of lower-risk zones with all types of land was roughly 20 percent of the total area of that type of land, with the area of lower-risk zones on lakes (42), reservoirs (43), beach land (46), and urban land (51) exceeding 40 percent of the total area of the type. In 2000, natural forest land and artificial forest land (21), scrubland (22), and lakes were partly within lower-risk areas, influenced by the land use type. In 2010, all of the marsh land (64) was in the lower-risk area.…”

“…(42), reservoirs (43), beach land (46), and urban land (51) exceeding 40 percent of the total area of the type. In 2000, natural forest land and artificial forest land (21), scrubland (22), and lakes were partly within lower-risk areas, influenced by the land use type. In 2010, all of the marsh land (64) was in the lower-risk area.…”

“…Zhou et al studied Karst Lake and its sub-basin, concluding that landscape type determines LER migration [20]. Zhao et al evaluated LER in Yuanmou Basin based on a topographic gradient and found that LER and its changes differed significantly across the topographic gradient [21]. Peng et al analyzed the spatial characteristics of LER in mining cities by taking Liaoyuan City as an example.…”