A new model for evaluating sustainable utilization of coastline integrating economic output and ecological impact: A case study of coastal areas in Beibu Gulf, China

Abstract Evaluation on sustainability of coastline utilization was one of the hot topics in marine environmental science. Based on high-resolution remote sensing images, coastlines can be divided into natural coastlines and artificial coastlines. Natural coastlines are mainly converted to harbor coastline and mariculture coastline. In this study, a new comprehensive model was proposed to assess the sustainability on utilization of coastline and applied to a typical case of Beibu Gulf, China. Comprehensive economic output efficiency (EOE) of artificial coastlines was obtained by integrating the contribution weight and applying linear combination model. In addition, the P–S-R framework integrated with fuzzy mathematics model and linear combination method was constructed to evaluate the disturbance intensity of human activities on the natural coastlines (DI) by taking petrochemical plants, ports, sewage outlets and aquaculture intensity as pressure indicators, seawater quality status near the coastline as state indicators, and whether the coastline was within nature reserve boundaries as the response indicator. Rely on the EOE and DI, the cities involved in the evaluation were finally categorized into four groups: group 1 with high economic output efficiency and low ecological impacts, group 2 with high economic output efficiency and high ecological impacts, group 3 with low economic output efficiency and low ecological impacts, group 4 with low economic output efficiency and high ecological impacts. The results showed that: (1) natural coastlines retention ratios were 52.45%, 57.97% and 76.15% in Guangdong, Guangxi and Hainan Province respectively. In addition, 8.66%, 10.47% and 5.17% of the coastlines with high disturbance from human activities in Guangdong, Guangxi and Hainan Province respectively were identified; (2) only 4 of 29 cities were categorized into the group with high economic output and low ecological impacts, indicating that most of the coastal cities in Beibu Gulf of China was at a relatively low level of sustainability. The proposed indices system and the integrated analysis framework were proved to be feasible for evaluating sustainable utilization of coastlines, which can be applied to other case studies. The results of evaluation provided valuable information for decision-makers to optimize coastal land use policy targeting at the balance of development and conservation.