Hard to believe it has been two years since my postdoc at James Cook University finished and I moved back to Canada to continue my research (and start teaching!) at the University of Victoria. Here is a synopsis of one recent paper, which characterizes my revitalized stream of research with indigenous people (here called First Nations) in British Columbia, Canada.
While no-fishing areas (a.k.a. no-take areas, marine reserves) are the gold standard of marine conservation, such restrictive measures are not always socially feasible. How effective, compared to no-take areas, are other kinds of conservation measures? The IUCN established a categorization of marine protected areas (MPAs), from most restrictive to least restrictive. In this study, we focused on three types of areas: no-take areas (IUCN Category I and II), those that allow some limited fishing (IUCN Category IV), and those that allow more extensive fishing yet have some restrictions that might not exist in areas under conventional fisheries management (IUCN Category VI).
To assess the effectiveness of these areas, we synthesized studies from around the world (i.e., carried out a meta-analysis). We classified these global examples by our selected IUCN Categories, using data that another study had collated but not analyzed by IUCN Category. These studies compared the biomass and density of fishes inside and outside of no-take areas compared to other MPAs (or zones within large, zoned MPAs), and/or inside and outside conventional fisheries management areas and MPAs.
We found the following: If we assume that no-take areas are the most effective marine conservation measure (i.e., are 100% effective), and that conventional fisheries management areas do not add additional value to marine conservation (i.e., are 0% effective), then areas with some restrictions (IUCN Category IV) are, on average, 60% effective, and little additional restrictions (IUCN Category VI) are 24% effective (Figure 1). These averages had wide ranges (confidence intervals), indicating that so far not too many studies exist that have examined effectiveness, and that the results range quite a lot.
We then applied these estimates of effectiveness to assess an existing and proposed network of MPAs on the coast of British Columbia, Canada. We were invited to do this work by four First Nations on the central coast of British Columbia, who developed a marine use plan that includes proposed MPAs with different levels of restrictions. We found that the proposed areas meet most conservation objectives, whereas MPAs that currently exist in this region are inadequate.
The empirical estimates we derived are important for marine conservation planning around the world. Too often conservation plans assume that all MPAs benefit biodiversity equally, when clearly that is not the case. The wide ranges in our results indicate that many more well-designed studies are needed to better understand the effectiveness of different areas. Still, at the moment, our study represents the best currently available estimate of the effectiveness of different IUCN Categories, and we encourage others to use them in MPA assessments and planning.
Ban, N. C., C. McDougall, M. Beck, A. K. Salomon, and K. Cripps. 2014. Applying empirical estimates of marine protected area effectiveness to assess conservation plans in British Columbia, Canada. Biological Conservation 180:134-148.
Abstract: 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.
