Mediterranean marine protected areas have higher biodiversity via increased evenness, not abundance

Research output: Journal contributionsJournal articlesResearchpeer-review


  • Shane A. Blowes
  • Jonathan M. Chase
  • Antonio Di Franco
  • Ori Frid
  • Nicholas J. Gotelli
  • Paolo Guidetti
  • Tiffany M. Knight
  • Felix May
  • Daniel J. McGlinn
  • Fiorenza Micheli
  • Enric Sala
  • Jonathan Belmaker
1. Protected areas are central to biodiversity conservation. For marine fish, marine protected areas (MPAs) often harbour more individuals, especially of species targeted by fisheries. But precise pathways of biodiversity change remain unclear. For example, how local-scale responses combine to affect regional biodiversity, important for managing spatial networks of MPAs, is not well known. Protection potentially influences three components of fish assemblages that determine how species accumulate with sampling effort and spatial scale: the total number of individuals, the relative abundance of species and within-species aggregation. Here, we examined the contributions of each component to species richness changes inside MPAs as a function of spatial scale.

2. Using standardized underwater visual survey data, we measured the abundance and species richness of reef fishes in 43 protected and 41 fished sites in the Mediterranean Sea.

3. At both local and regional scales, increased species evenness caused by added common species in MPAs compared to fished sites was the most important proximate driver of higher diversity.

4. Site-to-site variation in the composition (i.e. β-diversity) of common species was also higher among protected sites, and depended on sensitivity to exploitation. There were more abundant exploited species at regional scales than at local scales, reflecting a tendency for different protected sites to harbour different exploited species. In contrast, fewer abundant unexploited species were found at the regional scale than at the local scale, meaning that relative abundances at the regional scale were less even than at the local scale.

5. Synthesis and applications. Although marine protected areas (MPAs) are known to strongly influence fish community abundance and biomass, we found that changes to the relative abundance of species (i.e. increased evenness) dominated the biodiversity response to protection. MPAs had more relatively common species, which in turn led to higher diversity for a given sampling effort. Moreover, higher β-diversity of common species meant that local-scale responses were magnified at the regional scale due to site-to-site variation inside protected areas for exploited species. Regional conservation efforts can be strengthened by examining how multiple components of biodiversity respond to protection across spatial scales.
Original languageEnglish
JournalJournal of Applied Ecology
Issue number3
Pages (from-to)578-589
Number of pages12
Publication statusPublished - 01.03.2020

Bibliographical note

S.A.B. thanks the Marine Ecology & Biodiversity laboratory at TAU, the Biodiversity Synthesis group at iDiv, the editor and reviewers for constructive feedback at various stages of this project. This work was partially supported by an Israel Science Foundation (ISF) grant number 1356/15 to J.B. J.M.C., T.M.K., F.M. and S.A.B. gratefully acknowledge the support of the German Centre of Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig (funded by the German Research Foundation; FZT 118); T.M.K. was also supported by the Alexander von Humboldt Foundation; F.M. acknowledges support from the Stanford Woods Institute for the Environment.

    Research areas

  • beta-diversity, biodiversity, conservation, marine protected areas, protected areas, scale dependence
  • Gender and Diversity
  • Biology