Detect coastal disturbances and climate change effects in coralligenous community through sentinel stations

avoids the use of permanent fixed quadrats with many screws, therefore reducing effort, cost, maintenance and, most importantly, the impact on communities. As explained above, three to five of such monitoring points would be installed per site (Fig 4). A hand drill (Fig 4A), used in climbing, is proposed in the method. This tool is a cheap and relatively simple way to fix the pieces to the rock and can be supplied to diving clubs that are interested in being part of the monitoring network. The anthozoans Astroides calycularis (Pallas, 1766) and Paramuricea clavata (Risso, 1826), which are currently listed as ’vulnerable’ by the IUCN, were selected for monitoring. These spe- cies are vulnerable to increases in temperature and sensitive to deterioration of the environmen- tal quality of the marine environment. Both species are well referenced in ecological studies of coastal benthos [42,43,63, 81–88]. These species should always be moderate to large (preferably colonial) and highly visible while immersed. Moreover, some studies have indicated that typical coralligenous species, such as Paramuricea clavata, exhibit extremely low temporal variability [88]. Additionally, these species are highly representative of the community under study. There- fore, the quantitative stability (cover) of these sensitive species over time in the absence of phe- notypic signs of stress (e.g., epibiosis, partial necrosis, bleaching) would allow us to infer that the community has remained healthy. Therefore, focusing the monitoring effort on sensitive species

that are representative of the community should allow the appropriate inferences to be drawn. Sampling procedure Four fixed 1-m2 PVC quadrats were installed in two different locations. One setup had a verti- cal orientation (shady), and the other had a horizontal orientation (sunny) at a depth of 28 m Fig 3. Sentinel station showing permanent quadrats of 1x1m located on patches of target species. https://doi.org/10.1371/journal.pone.0231641.g003 PLOS ONE Detect coastal disturbances in coralligenous PLOS ONE | https://doi.org/10.1371/journal.pone.0231641 May 5, 2020 6 / 23