In coastal waters around the world, the dominant primary producers are benthic macrophytes, including seagrasses and macroalgae, that provide habitat structure and food for diverse and abundant biological communities and drive ecosystem processes. Seagrass meadows and macroalgal forests play key roles for coastal societies, contributing to fishery yields, storm protection, biogeochemical cycling and storage, and important cultural values. These socio-economically valuable services are threatened worldwide by human activities, with substantial areas of seagrass and macroalgal forests lost over the last half-century.

Tracking the status and trends in marine macrophyte cover and quality is an emerging priority for ocean and coastal management. This study presents a consensus assessment and recommendations on the current state of and opportunities for advancing global marine macrophyte observations, integrating contributions from a community of researchers with broad geographic and disciplinary expertise.

The authors of the study recommend a tiered observation system, with improvement of remote sensing and remote underwater imaging to expand capacity to capture broad-scale extent and intervals of several years, coordinated with stratified in situ sampling annually to characterize the key variables of cover and taxonomic or functional group composition, and to provide ground-truth. The importance of a robust network of macrophyte observation is also stressed.

It is concluded that realizing the recommendations in this study will produce more effective, efficient, and responsive observing, a more accurate global picture of change in vegetated coastal systems, and stronger international capacity for sustaining observations.

https://www.frontiersin.org/articles/10.3389/fmars.2019.00317/full

Duffy et al. (2019) Toward a coordinated global observing system for seagrasses and marine macroalgae. Frontiers in Marine Science 6:317.