Abstract
Marine protected areas (MPAs) are a critical defense against biodiversity loss in the world's oceans, but to realize near‐term conservation benefits, they must be established where major threats to biodiversity occur and can be mitigated. We quantified the degree to which MPA establishment has targeted stoppable threats (i.e., threats that can be abated through effectively managed MPAs alone) by combining spatially explicit marine biodiversity threat data in 2008 and 2013 and information on the location and potential of MPAs to halt threats. We calculated an impact metric to determine whether countries are protecting proportionally more high‐ or low‐threat ecoregions and compared observed values with random protected‐area allocation. We found that protection covered <2% of ecoregions in national waters with high levels of abatable threat in 2013, which is ∼59% less protection in high‐threat areas than if MPAs had been placed randomly. Relatively low‐threat ecoregions had 6.3 times more strict protection (International Union for Conservation of Nature categories I–II) than high‐threat ecoregions. Thirty‐one ecoregions had high levels of stoppable threat but very low protection, which presents opportunities for MPAs to yield more significant near‐term conservation benefits. The extent of the global MPA estate has increased, but the establishment of MPAs where they can reduce threats that are driving biodiversity loss is now urgently needed.
Highlights
Marine protected areas (MPAs) are a cornerstone of conservation and cover >7% of the world’s oceans (UNEP-WCMC 2018)
Approaches, such as National Geographic’s Pristine Seas program, which targets areas where political costs of large PAs are low and threats are anticipated to expand, will likely have significant longterm benefits (Sacre et al 2019). Such efforts have been criticized for potentially redirecting limited conservation resources from areas under immediate threat that are in great need of protection and for producing low return on conservation investments in the near term (Pressey 1994; Devillers et al 2015)
In 2013, 9.0% of national waters had protection, but only ß21% were within high-threat ecoregions
Summary
Marine protected areas (MPAs) are a cornerstone of conservation and cover >7% of the world’s oceans (UNEP-WCMC 2018). Several countries have recently received global attention for declaring vast MPAs. For example, the United States expanded the Pacific Remote Islands Marine National Monument to cover >1 million km and 80% of Palau’s Exclusive Economic Zone (EEZ) was designated a no-take area (UNEP-WCMC & IUCN 2016). The conservation effectiveness of PAs is often questioned because expansion frequently targets areas that are unlikely to be affected in the short or medium term; they deliver little conservation benefit relative to no action (e.g., Pressey et al 2002; Ferraro & Pattanayak 2006; Barnes 2015) Approaches, such as National Geographic’s Pristine Seas program, which targets areas where political costs of large PAs are low and threats are anticipated to expand, will likely have significant longterm benefits (Sacre et al 2019). To realize a near-term net conservation benefit PAs need to be established where conservation value is expected to decrease in the absence of action (i.e., area is under threat) and where conservation action (e.g., PA establishment) can reduce threats (Maron et al 2013)
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