Article ID: 2113
Aquatic systems are highly sensitive to anthropogenic effects and have suffered from invasion by non-native species in recent decades. Remote sensing products, used at appropriate spatial scales, are powerful tools for monitoring dynamics in aquatic vegetation and conserving native species. Here, I propose a high-resolution mapping method for aquatic vegetation using pole photogrammetry, and demonstrate its efficacy by mapping vegetation around a natural spring at the confluence of the Inukai and Katsura Rivers in the Yodo River watershed, Japan. A camera, attached to a stabiliser, was used to photograph vegetation. Captured videos were processed using Structure-from- Motion-Multi-view Stereo (SfM-MVS) photogrammetry to create orthomosaic images, from which species polygons were interpreted visually. The imagery resolution was adequate to identify vegetation to the species level. Therefore, it was possible to determine species cover and distribution within the study site using the orthorectified mosaic images. The resulting vegetation maps are highly valuable for ecosystem management and conservation in the study area, especially given that the spring area has high aquatic plant species richness, but has been experiencing an increase in non-native species cover.
