Spatiotemporal coastline variations in the Pearl River Estuary and the relationship with multiple human disturbances

Abstract

Coastlines and estuaries as one of the most dynamic systems in the marine environment are influenced by not only natural factors but also various anthropogenic activities, but there have been limited comprehensive studies on the relationship between coastline variation and anthropogenic activities at the watershed and local scales. The Pearl River Estuary (PRE) in China has experienced remarkable coastline variation along with rapid economic development and urbanization. In this study, the coastline of the PRE was extracted using Landsat images during 1987-2017, and the impacts of multiple factors on coastline variation were explored with correlation analysis and regression analysis. Results suggested coastlines of the PRE demonstrated a clear expanding trend over recent decades, and the coastline length had increased by 74.81 km and the land area had increased by 679.25 km2 by 2017, and results also showed rapid coastline variation during 1987-2004 and relatively slow variation during 2004-2017. Artificial coastlines accounted for 80.90% of the total coastline length in 2017, while natural coastlines accounted for only 19.10%. In addition, reduction in the sand content caused by construction of reservoirs and river dredging in upstream areas played a dominant role in affecting natural coastline variation in the PRE, especially on the west coast. Moreover, the artificial coastline in the study area expanded quickly due to the influence of various human activities, among which the urbanization and land reclamation for aquaculture played a dominant role in affecting the artificial coastline variation on the east and west coasts, respectively. Results of this study have important value for understanding the individual and joint effects of various human activities on coastline variation and can provide important reference information for the sustainable management of the PRE as well as other estuaries.

Study on the Erosion and Deposition Changes of Tidal Flat in Jiangsu Province Using ICESat-2 and Sentinel-2 Data

“…The factors influencing the sedimentation dynamics of tidal flats in Jiangsu are highly complex. Generally, the key determinants of tidal flat development or erosion include sediment sources, hydrodynamic conditions, and anthropogenic influences [36][37][38]. Along the Jiangsu coast, an abundant supply of fine-grained sediments leads to their accumulation under tidal action, which results in wave energy dissipation and reduced wave impact.…”

“…Furthermore, human activities are also contributing factors to tidal flat evolution [38]. In the segment from the GuanHe River mouth to the north of the Abandoned-Yellow-River mouth (segment 5), sediment accumulation occurs due to the presence of a guide levee at the Guan River mouth.…”

Quantitative Analysis of Rapid Siltation and Erosion Caused Coastline Evolution in the Coastal Mudflat Areas of Jiangsu

“…The seawall weakened the tidal current bearing capacity, resulting in continuous siltation of sediment in front of the embankment, leading to gradual siltation of the upper part of the new tidal flat section. The evolution pattern of "upward siltation and downward intrusion" formed around the transition zone is the geomorphic response mode of coastal tidal flat reclamation activities [63]. The siltation in the upper section was further advanced, and a new coastline gradually formed, but human reclamation activities promoted the coastline to advance to the sea to a certain extent and caused the erosion of tidal flats in front of the coastline.…”

Population parameters and heterogeneity in survival rates of Indo-Pacific humpback dolphins in a heavily urbanized coastal region of southeast China: implications for conservation

“…A greatly accelerated process of urbanization and industrialization, along with massive coastal alterations and land reclamation have degraded much of the PRD coastal habitats, especially at the eastern reaches of the region in Lingding Bay 1 (Wu et al, 2016) which represents the main body of the Pearl River estuarine system. In the absence of effective environmental management strategy, major anthropogenic perturbations over the past decades have turned Lingding Bay (LB) into one of the most polluted and ecologically disturbed estuaries in the world (Li and Damen, 2010;Wang et al, 2016;Wu et al, 2016;Wang and Rainbow, 2020;Li et al, 2022). While much of the environmental health of LB has been severely compromised (Wang and Rainbow, 2020), any attempts at protection of its cetacean inhabitants have been further hampered by the lack of basic knowledge of their population demographic processes and structure (Karczmarski et al, 2016).…”

“…Various environmental factors also vary spatially in LB. Numerous manmade stressors differ in their type (e.g., habitat loss, pollutant load, maritime traffic, underwater noise) and intensity (e.g., extent of habitat destruction, intensity of fisheries pressure) across the anthropogenic seascape of LB (Chen et al, 2013;Wang et al, 2016;Wu et al, 2016;Yu et al, 2016;Gui et al, 2017;Pine et al, 2017;Gui et al, 2019;Guo et al, 2022;Li et al, 2022). Correspondingly, there is a considerable spatial heterogeneity in dolphin prey resources, an apparent result of heavy fishing pressure in the region (e.g., Duan et al, 2009;Lin et al, 2019;Zhou et al, 2019).…”