Influence of Landscape Pattern Changes on Runoff and Sediment in the Dali River Watershed on the Loess Plateau of China

Yan Zhang,Yang Yu,Zhilei Bi,Xin Zhang

doi:10.3390/land8120180

Yan Zhang, Yang Yu + Show 2 more

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https://doi.org/10.3390/land8120180

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Abstract

The large-scale Grain for Green project on the Loess Plateau of China significantly changes the regional landscape pattern, which has a profound impact on runoff and sediment process. The relationship between landscape pattern and runoff and sediment in the Dali River watershed is established. Cropland and grassland areas in the watershed show a downward trend, whereas the woodland and building land increases continuously. The Number of Patches (NP), Patch Density (PD) and Landscape Diversity (SHDI), Landscape Division Index (DIVISION) increase significantly. The Largest Patch Index (LPI) and Landscape Shape Index (LSI) show overall change in the rising and falling rule. The Contagion Index (CONTAG) and Cohesion Index (COHESION) first increase, then decrease. A decreasing trend is shown by runoff and sediment. The annual runoff in 2010 was 29.76% less than in 1960, and the annual sediment load was 84.87% less. NP, PD, COHESION, DIVISION and SHDI have a significant negative correlation with runoff and sediment, and CONTAG and runoff sediment are positively related. This study could provide theoretical support for guiding watershed land use and landscape planning to effectively reduce runoff and sediment transport.

Highlights

The ecological environment of the Loess Plateau of China is fragile
The large-scale conversion of farmland to forests on the Loess Plateau has a profound impact on the regional land use/land cover pattern
From 1980 to 2010, the area of cropland in Dali River watershed decreased by 134.29 km2, and 7.63% of cropland was converted into grassland and forestland

Summary

Introduction

The ecological environment of the Loess Plateau of China is fragile. Affected by natural factors such as broken terrain, loose soil, and concentrated rainfall in summer, soil erosion is serious in this region [1]. The frequent human activities, overgrazing, excessive reclamation, deforestation, and other human factors have been intensifying the regional ecological environment deterioration, resulting in the soil erosion area on the Loess Plateau region expanding year by year [2]. The Yellow River transported about 0.1–0.2 billion tons of sediment annually since 2010 [3,4]. Serious soil erosion on the Loess Plateau affects the ecological security of the Yellow River, and restricts the sustainable development of regional social economy for a long time [5].

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