The park never born: Outcome of a quarter of a century of inaction on the sea‐floor integrity of a proposed but not established Marine Protected Area

Abstract

1. Marine Protected Areas (MPAs) are a major tool to conserve marine ecosystems but are also strongly attractive to tourists, the increased numbers of which can cause environmental issues if not properly managed.2. Proposing an MPA and then failing to establish it risks advertising the beauty of a marine area without managing the unavoidable increase in tourism. This is what happened at Gallinara Island (Ligurian Sea, north-western Mediterranean), where an MPA was proposed in 1990 but has not yet been established. 3. Benthic data collected soon after the proposal (1990-92) have been compared with similar information obtained in subsequent periods (2009 and 2016): change has been assessed both visually and statistically, using multivariate and univariate techniques. 4. The Gallinara sea floor supported five epibenthic communities in 1991, four of which corresponded to European Nature Information System (EUNIS) habitats; the fifth epibenthic community, characterized by the erect sponge Axinella polypoides, should be included in the next revision of EUNIS. 5. In the 25 years since the original MPA proposal, all epibenthic communities have exhibited a reduction in their three-dimensional structure and biotic homogenization, and severe decreases in species diversity, and the sea floor has been littered with derelict fishing gear and other waste from boats. 6. In absence of the MPA, proposals to develop a management plan for a marine Site of Community Importance (SCI) have been provided, to reduce sea-based human pressures. The dramatic alteration of Gallinara sea floor after 25 years of negligence and inaction is a sad warning for other unmanaged yet beautiful natural areas within urbanized regions of the world.

You cannot conserve a species that has not been found: The case of the marine sponge Axinella polypoides in Liguria, Italy

“…Portofino), pointing to the capacity for persistence – if undisturbed – of this long‐lived species (Coppari et al, 2016); however, available quantitative data indicate that in localities deprived of any form of protection population size has decreased (e.g. Gallinara: Bianchi et al, 2018).…”

“…When available from either the literature or recent field surveys, abundance data were used to evaluate population size. Scuba surveys employed quadrants of 4 m 2 (Bianchi et al, 2004) or belt transects of variable length and 1 m total width (Bianchi et al, 2018). Belt transects, of variable length and 0.5 m total width, were also employed by ROV surveys (Enrichettiet, Bo, al., 2019).…”

An Alien Invader is the Cause of Homogenization in the Recipient Ecosystem: A Simulation-Like Approach

“…We drew the convex hulls, i.e., the smallest convex polygons enclosing the sample points, in both scatter plots to visualize and compare graphically the respective multivariate dispersions. In addition, for each dataset we computed the average dissimilarity (1-Bray-Curtis coefficient), the standard deviation, and the coefficient of variation among samples, with lower values of these indices being indicative of reduced β-diversity, and hence homogenization [69]. There was no difference in the occurrence of C. cylindracea among areas with varying degree of protection (Figure 4b), nor among the years 2012 to 2017 (Figure 4c), as indicated by the large overlap among error bars.…”

Abrupt Change in a Subtidal Rocky Reef Community Coincided with a Rapid Acceleration of Sea Water Warming

“…The temporal rate of change of the whole coralligenous community of the rocky reef was assessed by computing the average (± standard error) Euclidean distance between the photoquadrats of a given year and the centroid of the photoquadrats of 1961, thus allowing direct comparison with a previous study [33]. Finally, the average (± standard error) Coefficient of Variation (CV%) of Euclidean distances was calculated for each year, lower CV values indicating biotic homogenization [48,49]. Change in community structure was analysed using primarily the Shannon-Wiener diversity index, computed with the natural logarithm ln.…”