Long-Time-Series Evolution and Ecological Effects of Coastline Length in Coastal Zone: A Case Study of the Circum-Bohai Coastal Zone, China

Abstract

Under the joint influence of climate change and human production and living activities on land and sea, the morphology and use function of the coastline have undergone notable changes, triggering more significant environmental and ecological effects. In this paper, we quantified the evolution characteristics of the coastline over the past 30 years and measured the possible environmental pollution and ecological degradation by means of spatiotemporal coupling analysis in terms of spatial form and land-use function. The Chinese Bohai Rim region was taken as an example, and the Google Earth Engine was applied to achieve a long time series of interannually continuous land use function classification of the coastal zone. The study shows that: (1) from 1987–2020, the coastline of Bohai Rim showed an overall trend of seaward expansion, with the length of the coastline increasing by 15.6%, most significantly from 2003 to 2011; (2) the proportion of construction function coastline increased from 14.66% to 42.8%, while the proportion of cropland coastline decreased from 52.01% to 18.16% during 2000–2020, with the natural ecological coastline decreasing in the early stage and recovering in the later stage, thus becoming more stable overall; (3) 82.73% of coastal districts and counties showed a linear correlation between changes in coastline function and water quality level, and 77.8% showed a consistent degree of change of coastline function and loss of ecological land, indicating that changes in the coastline have triggered significant problems in terms of environmental pollution and ecological degradation. With the exception of localized areas such as the Yellow River Delta, where coastline change is somewhat more significantly influenced by environmental climate change, most other coastline changes are primarily due to human land-based development; therefore, coastal policy constraints bring obvious mitigation.

Spatial-Temporal Pattern of Land Use and SDG15 Assessment in the Bohai Rim Region Based on GEE and RF Algorithms

“…The Bohai Rim lies within the temperate monsoon climate zone, characterized by distinct seasonal variations and favorable light and water-heat conditions during summer [27] The region's topography mainly consists of hills and plains, boasting abundant land resources. Liaoning and Shandong provinces, in particular, hold extensive coastline resources and a significant total scale of sea resources [28]. This region is rich in wetland resources, with a mudflat area of over 68.04*104 km 2 [29], concentrated in the Yellow River Delta and Liaohe River Delta, which provide abundant material products and ecological services for the regional socioeconomy.…”

High-Resolution Real-Time Coastline Detection Using GNSS RTK, Optical, and Thermal SfM Photogrammetric Data in the Po River Delta, Italy

“…These challenging environments are characterized by large topographic changes, differences in bed cover (rough surfaces alternating with textureless and reflective surfaces), the presence of water as channels, thin patches and deeper puddles, variations in the coastline due to the combined effects of human activities on land and sea, regional environmental modification, and climate change. All these effects can represent important challenging aspects for the monitoring of these areas [8].…”

Enhanced Impact of Land Reclamation on the Tide in the Guangxi Beibu Gulf

“…The data used in this study are mainly from the following four resources: Landsat satellite data (Table 1) with a spatial resolution of 30 m are widely used for shoreline identification and assessment and have been proven to be a reliable method [30,31]; the Radar Altimeter Database System (http://rads.tudelft.nl, accessed on 6 July 2023) provides access to the satellite altimeter data used in our investigation, including the tidal harmonic constants derived for 25 years from TOPEX/Poseidon (T/P), which was used in a two-dimensional tidal model of the Guangxi Beibu Gulf; the ETOPO1 ocean bathymetry data, which had a spatial resolution of 1/60 • × 1/60 • and was released in October 2020 through https://data.nodc.noaa.gov (accessed on 13 July 2023); the bathymetry data for the inner bay, which was obtained from marine charts published by the China Maritime Safety Administration; and the statistical data from the Guangxi Statistical Yearbooks (1995-2015) [32] and the China Marine Statistical Yearbook (1995-2015) [33]. The coastline obtained through the remote sensing automatic classification method essentially represents the instantaneous water's edge at the time when the satellite passes over.…”