Ecological risk assessment of exploitation and utilization in Chuanshan Archipelago, Guangdong province, China

Abstract

Islands are an important part of marine territory and of significant economic and military importance. At the same time, islands are a kind of special ecosystem with unique and fragile ecological environment. With the rapid development of marine economy, the exploitation and utilization degree has increased significantly, and the ecological environment of islands has suffered from the great shock and damage. These lead to the trend of environment degradation and disaster exacerbation. For a long period, natural disasters have been the main risk source of island ecosystem, but in recent years human exploitation and utilization activities have been major risk source. The Chuanshan Archipelago consists of the Shangchuan Island, Xiachuan Island, Mangzhou Island and so on. It is located in the west of Pearl River estuary and is an important sea barrier in central Guangdong province, China. Affected by ocean monsoon, the climate there is mild and pleasant. And the tourism resources are abundant and unique, so the number of tourists to island is too many. In addition, it also has many natural harbors such as Shadi harbor and Nao'ao harbor. Therefore, the exploitation and utilization activities such as tourism recreation and marine aquaculture are frequent, which causes the great challenge in the ecosystem of Chuanshan Archipelago. Based on the ecological risk assessment frame proposed by the Environmental Protection Agency (EPA), this paper analyzed the ecological endpoints, habitat types and press sources of Chuanshan Archipelago. A conceptual model which was proposed to characterize the relationships between the above three factors. The ecological risk of exploitation and utilization in Chuanshan Archipelago was evaluated using the Relative Risk Model (RRM). The comprehensive risk value is 7.745 in Shangchuan Island, which shows the utilization risk is high. The two subsystems of Shangchuan Island, tidal flats and shallow sea, are the major risky regions, especially the rocky beach in the tidal flats. The tourism recreation and marine aquaculture are the main sources of risk. The rare waterfowl is the most threatened species. The comprehensive risk value is 2.317 in Xiachuan Island, the exploitation risk is lower than that of Shangchuan Island because the pressure from the three subsystems of insular terrene, tidal flats and shallow sea is small. The main risks come from the marine aquaculture, tourism recreation and urban land-use which also threaten the rare waterfowls and accipiter. Based on the result above, this paper outlines the risk management countermeasure of tourism and marine aquaculture in Shangchuan Island and Xiachuan Island, which includes the following parts: controlling the number of tourists to island strictly, strengthening the ecological management of island, reducing the waste caused by tourism and domestic garbage to the best of their abilities, reinforcing the management of marine aquaculture and removing the abandoned and illegal breeding pools, prohibiting production and exploitation activities in nature reserve, and so on. These findings may provide decision-making support and management basis for the ecological environment protection and sustainable utilization of island.