Local benthic assemblages in shallow rocky reefs find refuge in a marine protected area at Madeira Island

João Canning-Clode,Cláudia Ribeiro,Ignacio Gestoso,Manfred Kaufmann,Filipe Alves

doi:10.1007/s11852-018-0669-y

Abstract

The patterns of variability in the composition and structure of benthic communities along two depth strata (5 and 10 m) and the presence of sea urchins in structuring the subtidal rocky reefs were quantified in a long-established coastal marine protected area (Garajau MPA) and in two size equivalent and contiguous impacted areas (one highly urbanized and other with high fishing pressure) at Madeira Island (northeast Atlantic). Results suggest i) the MPA could be acting as a refuge for local biodiversity, ii) communities from the highly fished area could be suffering an impoverishment of local biodiversity, and iii) communities from the highly urbanized area would be enriched by the establishment of opportunistic species. These findings support that the level of human-pressure likely plays an important role in the composition of benthic communities in this insular ecosystem, although this was more relevant at the shallower stratum where the key grazer Diadema africanum explained 65% of the variance of benthic assemblages. It is suggested that this MPA small dimension and proximity to human impacted areas are limiting the survival of predators of the D. africanum.

Highlights

Marine coastal ecosystems are highly exposed to humaninduced pressures, and as a consequence are vulnerable to changes in the biotic structure and composition of ecological communities (Kappel 2005; Jiao et al 2015; Aucelli et al 2018)
No resident population inhabits the coastline of the Garajau MPA, and its human pressure comes from SCUBA activities and two small land stations supporting swimmers mainly during summer
The Protected and Urbanized areas differentiated from the Non-protected area, by presenting higher species richness and diversity

Summary

Introduction

Marine coastal ecosystems are highly exposed to humaninduced pressures, and as a consequence are vulnerable to changes in the biotic structure and composition of ecological communities (Kappel 2005; Jiao et al 2015; Aucelli et al 2018). MPAs are vulnerable to development and exploitation occurring outside those areas, especially when considering small coastlines that cannot be integrated into spatial development strategies for larger areas (Roberts et al 2005; Castrejón and Charles 2013) This is common with small MPAs located in the vicinities of non-protected and/or urbanized areas, where it is more challenging to successfully linkage the ecological, social and economic roles (Cicin-Sain and Belfiore 2005), as in many insular ecosystems (Hernández et al 2008b; Abecasis et al 2013; Friedlander et al 2013, 2017)

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Results

Conclusion