Submerged aquatic vegetation: Overview of monitoring techniques used for the identification and determination of spatial distribution in European coastal waters

Abstract

Coastal waters are highly productive and diverse ecosystems, often dominated by marine submerged aquatic vegetation (SAV) and strongly affected by a range of human pressures. Due to their important ecosystem functions, for decades, both researchers and managers have investigated changes in SAV abundance and growth dynamics to understand linkages to human perturbations. In European coastal waters, monitoring of marine SAV communities traditionally combines diver observations and/or video recordings to determine, for example, spatial coverage and species composition. While these techniques provide very useful data, they are rather time consuming, labor‐intensive, and limited in their spatial coverage. In this study, we compare traditional and emerging remote sensing technologies used to monitor marine SAV, which include satellite and occupied aircraft operations, aerial drones, and acoustics. We introduce these techniques and identify their main strengths and limitations. Finally, we provide recommendations for researchers and managers to choose the appropriate techniques for future surveys and monitoring programs. Integr Environ Assess Manag 2022;18:892–908. © 2021 SETAC

Innovative and practical tools for monitoring and assessing biodiversity status and impacts of multiple human pressures in marine systems

“…However, these methods often come short for shallow water coastal zones. Satellite remote sensing offers large spatial coverage but low spatial resolution, with RGB and spectral data acquisition at resolution of tens to hundreds of meter scales (Lønborg et al, 2022). Larger research vessels are limited to water depths deeper than ~10 meters and have high running costs.…”

Introduction to the special series, “The future of marine environmental monitoring and assessment”

“…The second paper (Huber et al, 2022), continues along the lines suggested by Lønborg et al (2022). It describes an SAV monitoring platform combining Sentinel-2 satellite imagery and ML techniques for advanced mapping of SAV in Swedish nationwide marine waters.…”

“…The first paper (Lønborg et al, 2022) compares traditional methods and emerging remote sensing technologies to monitor submerged aquatic vegetation. Submerged aquatic vegetation (SAV) is a vital ecosystem element, as SAV influences the overall functioning of coastal ecosystems by (1) providing food, for example, for herbivorous waterbirds; (2) being shelter and hatching and nursery areas for many animals (e.g., fish); (3) improving water quality by absorbing nutrients; and (4) stabilizing sediments and decreasing HD energy, thus increasing sedimentation and water clarity (Lønborg et al, 2022). Hence, SAV is an ecosystem-defining parameter and SAV supports biodiversity in many ecosystems.…”

“…Submerged aquatic vegetation data have traditionally been supported by samples collected by divers and/or video transects, but this is time‐consuming, labor‐intensive, and gives a limited overview of the spatial coverage. Lønborg et al (2022) conclude that a range of promising technologies exists for monitoring marine SAV. No technology is perfect—including the traditional diver and/or video transects—and Lønborg et al (2022) suggest combining different technologies and increasing the use of machine learning (ML) models for postprocessing of data.…”

“…Lønborg et al (2022) conclude that a range of promising technologies exists for monitoring marine SAV. No technology is perfect—including the traditional diver and/or video transects—and Lønborg et al (2022) suggest combining different technologies and increasing the use of machine learning (ML) models for postprocessing of data.…”