The shoreline change is the most direct factor in studying landform erosion and deposition. The Huanghe River Delta is the world’s fastest-growing delta, and understanding its coastline changes and evolution trends is crucial to regional ecological environment protection, marine resource development, and infrastructure construction. In this study, we combined modified normalized difference water index (MNDWI) and multi-year water frequency index (MWFI) to analyze water quality in typical years from 1976 to 2021, based on previous research. We visually interpreted 207 remote sensing images to obtain an annual coastline that makes the obtained coastline more scientific and representative. We then analyzed the temporal and spatial evolution and stability characteristics of the coastline through quantitative calculations to explore the Qingshuigou sub-delta coastline of the Yellow River’s evolution mechanism since 1976. Our main findings are as follows: (1) In general, the evolution of Qingshuigou sub-delta coastline shows a trend of rapid sedimentation towards the sea, followed by fluctuations and stability. We can divide it into “rapid development” and “slow development,” with the “dynamic equilibrium” in between, taking 1996 and 2002 as nodes. (2) Over the past 45 years, the stability of the coastline in the study area has continued to increase. The coastline of the section of the coastline and the abandoned estuary section of Qingshuigou is relatively active, and its coastline stability index is generally lower than 0.5. (3) The migration of the sedimentation and erosion center of the land delta corresponds to the estuary location’s change, especially the migration of the sedimentation center, which has a positive relationship in the longitude direction between the change of the estuary position and the position of the estuary, R2 = 0.690 4. (4) The Huanghe River’s sediment reduction into the sea, the relocation of the estuary position, and human activities have a significant impact on the delta coastline’s development and evolution. In the long run, the Huanghe River’s silt into the sea is still continuously reducing, and the future of the delta is still facing the threat of erosion.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |