Intertidal species richness and abundances in a recent small Marine Protected Area in Portugal: lack of effects from protection suggests changing strategies in the future

Abstract: Marine protected areas (MPAs) are being created around the world as the concern on species and habitats preservation is growing. A widespread concern related to the important lack of regulation and effective conservation measures has been raised, calling the attention to the importance of no-take areas within MPA’s. To justify more restrictive management decisions, it is essential to collect data and obtain baseline information that will allow to disentangle natural oscillations in ecosystems from human driven unbalances. This thesis focuses on the Avencas Marine Protected Area (AMPA), created in 2016. The intertidal biodiversity within the MPA has been compared with the one from surrounding areas. More than a hundred species of fish, invertebrates and algae have been morphologically and/or genetically identified from November 2019 to July 2020. DNA barcoding has been a key tool in this project, highlighting its high help potential to monitor MPAs and non-indigenous species (NIS) presence. The results showed no differences between species richness and abundances inside and outside the AMPA, suggesting the need of its geographical expansion, more restrictive regulations and/or stronger enforcement measures to reduce the impact of fishing or other recreative activities, and the pressure created by high human presence on this coast. Slightly higher intertidal abundances in the east side of AMPA suggest that there is an interesting community to protect there and that a potential eastward expansion of the protection would be more effective, especially knowing that larger protected areas usually have a higher effectiveness. Complementary protection measures could also include a community observed along the West coast near Cabo Raso. This region, 10km westward from the AMPA, encompasses an exposed rock coastal area with a complex topography. A new larger MPA would increase the effectiveness protecting coastal marine biodiversity in this region.