Quantifying and mapping intertidal oyster reefs utilizing LiDAR-based remote sensing

Restoration and conservation of the eastern oyster Crassostrea virginica requires information on its distribution and abundance, which is logistically difficult to obtain. We demonstrate how light detecting and ranging (LiDAR) can be used to obtain this information in a model intertidal system within the Virginia Coast Reserve (VCR) on the eastern shore of Virginia, USA. Specifically, we determined how LiDAR-derived data can be used to classify land cover and identify intertidal oyster reefs. We used the locations of existing reefs to determine the physical characteristics of oyster habitat through the use of elevation, fetch, and water residence time data for the region. Trained with elevation, intensity, surface slope, and curvature data, the land cover classification identified oyster land cover with an accuracy of 81%. Ground-truth patches were small, with the 50th percentiles for area and perimeter being 11.6 m(2) and 14.5 m, respectively. Reef crests occurred in a narrow range of elevation (-0.81 to -0.18 m relative to NAVD88) and patches had an average vertical relief of 0.14 m. The habitat suitability analysis located 52.4 km(2) of total oyster suitable habitat, or 12.03% of the mapped area with elevation, fetch, and residence time characteristics similar to those of existing reef area. This suggests that there is ample viable intertidal area for future oyster population restoration. Results also indicate that LiDAR data, coupled with physical attributes of existing reefs, can be used to target and prioritize locations for future restoration efforts in intertidal habitats.