China was the world’s top aquaculture producer, contributing 61.5% to the world production and has undergone tremendous expansion of aquaculture. Aquaculture has rapidly expanded at coastal regions of China and was responsible for large scale loss and fragmentation of wetland habitats through land reclamation and conversion. Monitoring and mapping of aquaculture ponds are of utmost importance for the sustainable management of coastal ecosystems.
Researchers from developed an object-based automatic classification and change detection method and generated maps of coastal aquaculture ponds in China from 1984 to 2016 using time series Landsat data. The first comprehensive and consistent national coastal aquaculture ponds database, CAS_Coastal Aquaculture, at 30-m spatial resolution was created. Based on this database, the spatial-temporal dynamics and main driving factors of coastal aquaculture ponds expansion were explored.
The results showed that the country's total area of coastal aquaculture ponds expanded by 10,463 square kilometers, which showed a sharp four-fold increase over the past 32 years. The provinces of Guangdong, Shandong and Jiangsu had significant increases of aquaculture ponds areas, accounting for 83 percent of the total number of expanded ponds. Most of the expanding aquaculture ponds were converted from natural wetlands and arable land.
The research is expected to study China's coastal artificial wetland ecosystem and provide support to figure out solutions for wetland sustainable utilization, scientific protection and land resources planning. This work has been published by International Journal of Applied Earth Observation and Geoinformation (doi.org/10.1016/j.jag.2019.101902).