Applying empirical estimates of marine protected area effectiveness to assess conservation plans in British Columbia, Canada
While efforts to meet international commitments to counter biodiversity declines by establishing networks of marine protected areas (MPAs) continue, assessments of MPAs rarely take into account measures of effectiveness of different categories of protection, or other design principles (size, spacing, governance considerations). We carried out a meta-analysis of ecological effectiveness of IUCN Categories I–II (no-take), IV and VI (MPAs) compared to unprotected areas. We then applied our ecological effectiveness estimates – the added benefit of marine protection over and above conventional fisheries management – to a gap analysis of existing MPAs, and MPAs proposed by four indigenous groups on the Central Coast of British Columbia, Canada. Additionally, we assessed representation, size, spacing, and governance considerations against MPA design criteria outlined in the literature. We found significant differences in response ratios for IUCN Categories IV and VI MPAs compared to no-take reserves and areas open to fishing, although variability in responses was high. By rescaling the predicted ecological effectiveness ratios (including confidence estimates), we found that, compared to no-take reserves (biodiversity conservation effectiveness 100%) and open fishing areas (0% additional biodiversity contribution over and above conventional fisheries management), IUCN Category IV had a predicted effectiveness score of 60%, ranging between 34% and 89% (95% lower and upper confidence intervals, respectively), and IUCN Category VI had a predicted effectiveness score of 24% (ranging between −12% and 72% for the 95% lower and upper confidence intervals, respectively). We found that the existing MPAs did poorly when compared against most MPA design criteria, whereas the proposed MPA network achieved many of the best practices identified in the literature, and could achieve all if some additional sites were added. By using the Central Coast of British Columbia as a case study, we demonstrated a method for applying empirically-based ecological effectiveness estimates to an assessment of MPA design principles for an existing and proposed network of MPAs.