Bivalves such as mussels (Mytilus edulis) and Pacific oysters (Crassostrea gigas) occur intertidal areas where they form irregularly shaped beds which change shape due to death and recruitment processes. Intertidal beds of blue mussels and Pacific oysters are important for community composition and ecological functioning of coastal systems. It is hard and labour intensive to measure coverage and density in the field.
The objective of this pilot project was to gain experience mapping intertidal features such as bare mudflat, the coastline, bivalve beds and gullies. We used an UAV equipped with a RGB and multispectral camera (Parrot Sequoia).
We selected a small and heterogeneous intertidal area near de Cocksdorp on the island of Texel in the Dutch Wadden Sea. We established a target area, flew data collection missions at different altitudes and produced maps of the collected images.
The raw maps show the potential for detailed delineation of typical intertidal structures such as bare mudflats and bivalve beds. Gullies and pools also show up clearly in the NDVI map (water has low NDVI values due to low reflectance). The project also illustrates the possibility to use multispectral sensors to obtain detailed insight into microphytobenthos distribution and production.
Above Orthomosaic of target area.
Above NVDI overlay of target area.