Monitoring mangrove phenology using camera images

Mangrove conservation is known as a significant means of sequestering atmospheric carbon dioxide to help mitigate climate change. Recently, a network called "Phenocam" has initiated the use of low-cost camera photos to monitor vegetation phenology world-wide. Despite that Phenocam has been proved to be feasible and useful for many tree species, to the authors' knowledge, the Phenocam approach has not been tested on mangroves. In this paper, we first collected two months of repeated digital camera photos capturing mangroves in the Mai Po Nature Reserve (MPNR), Hong Kong. Then, vegetation indices were extracted from the camera photos and validated with in situ measured NDVI. The feasibility, effectiveness, and potential biases of using camera photos to monitor the phenology of mangroves are discussed.