Macroalgal communities have an essential role in the shallow benthic habitats of temperate seas, where changes in their composition can resonate through entire coastal ecosystems. As all mayor ecosystems on Earth, algal beds have already been affected by multiple disturbances. Passive conservation tools, such as marine protected areas (MPAs) or No-take zones, have the potential to reduce some of the anthropogenic impacts by limiting human activity.

This study evaluated the natural variability of macroalgal communities’ composition inside and outside a Mediterranean No-take marine reserve during 15 years. The authors described their temporal dynamics considering their main drivers and tested the effect of protection in seaweed beds.

The results show that no differences were found either in the composition of the macroalgal assemblages or the total algal cover between protected and non-protected locations over the 15 years of study. However, the authors observed a positive effect of the protection increasing the cover of some specific species, such as the canopy-forming Treptacantha elegans.

It is concluded that the results highlight the importance of obtaining long-term data in ecological studies to better understand the natural variability of marine communities. The authors suggest that a robust understanding of the community dynamics would help avoiding misinterpretations between “impacted” or “in-recovery” communities when recovery times are longer than the study periods.

Medrano et al. (2019) Long-term monitoring of temperate macroalgal assemblages inside and outside a No take marine reserve. Marine Environmental Research