Poor ecological representation by an expensive reserve system: Evaluating 35 years of marine protected area expansion

Kerstin Jantke,Alienor L.M Chauvenet,James E.M Watson,Kendall R Jones,James R Allan,Hugh P Possingham

doi:10.1111/conl.12584

Abstract

AbstractGlobal areal protection targets have driven a dramatic expansion of the marine protected area (MPA) estate. We analyzed how cost‐effective global MPA expansion has been since the inception of the first global target (set in 1982) in achieving ecoregional representation. By comparing spatial patterns of MPA expansion against optimal MPA estates using the same expansion rates, we show the current MPA estate is both expensive and ineffective. Although the number of ecoregions represented tripled and 12.7% of national waters was protected, 61% of ecoregions and 81% of countries are not 10% protected. Only 10.3% of the national waters of the world would be sufficient to protect 10% of each ecoregion if MPA growth since 1982 strategically targeted underrepresented ecoregions. Unfortunately 16.3% of national waters are required for the same representative target if systematic protection started in 2016 (an extra 3.6% on top of 12.7%). To avoid the high costs of adjusting increasingly biased MPA systems, future efforts should embrace target‐driven systematic conservation planning.

Highlights

The need to conserve marine biodiversity using site-based strategies like protected areas (PAs) has been increasingly recognized over the last four decades (Halpern, 2003; Klein et al, 2015; Roberts, 1997)
While representation as measured by protection equality (PE) does not necessarily increase with more area under protection, we found a tripling of ecoregional representation levels (3.4-fold increase) since 1982, and a doubling of country-level representation (2.3-fold increase) (Figure 1)
As the marine protected area (MPA) estate has expanded since 1982, ecoregional representation has been consistently higher than country-level representation, with the proportion of adequately represented ecoregions almost double that of countries in the current MPA estate

Summary

Introduction

The need to conserve marine biodiversity using site-based strategies like protected areas (PAs) has been increasingly recognized over the last four decades (Halpern, 2003; Klein et al, 2015; Roberts, 1997). When marine protected areas (MPAs) are well resourced, well placed, and well managed they halt many threats to biodiversity and the unsustainable use of the ocean, such as destructive fishing practices, overharvesting, and coastal engineering (Edgar et al, 2014; Lester et al, 2009; Watson, Dudley, Segan, & Hockings, 2014). Most recent Strategic Plan for Biodiversity 2011–2020, with Aichi target 11 calling for effective, area-based protection of “at least [...] 10% of coastal and marine areas” (CBD, 2010). The UN Sustainable Development Goals, adopted in 2016, mandate the conservation of “at least 10% of coastal and marine areas” by 2020 (United Nations, 2015)

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Discussion

Conclusion