Search

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. [ABSTRACT FROM AUTHOR]

Anthropogenic conversion of natural habitats is the greatest threat to biodiversity and one of the primary reasons for establishing protected areas (PAs). Here, we show that PA establishment outpaced habitat conversion between 1993 and 2009 across all biomes and the majority ( n = 567, 71.4%) of ecoregions globally. However, high historic rates of conversion meant that 447 (56.2%) ecoregions still exhibit a high ratio of conversion to protection, and of these, 127 (15.9%) experienced further increases in this ratio between 1993 and 2009. We identify 41 'crisis ecoregions' in 45 countries where recent habitat conversion is severe and PA coverage remains extremely low. While the recent growth in PAs is a notable conservation achievement, international conventions and associated finance mechanisms should prioritize areas where habitat is being lost rapidly relative to protection, such as the crisis ecoregions identified here. [ABSTRACT FROM AUTHOR]

Summary As human activities increasingly threaten biodiversity [ 1, 2 ], areas devoid of intense human impacts are vital refugia [ 3 ]. These wilderness areas contain high genetic diversity, unique functional traits, and endemic species [ 4–7 ]; maintain high levels of ecological and evolutionary connectivity [ 8–10 ]; and may be well placed to resist and recover from the impacts of climate change [ 11–13 ]. On land, rapid declines in wilderness [ 3 ] have led to urgent calls for its protection [ 3, 14 ]. In contrast, little is known about the extent and protection of marine wilderness [ 4, 5 ]. Here we systematically map marine wilderness globally by identifying areas that have both very little impact (lowest 10%) from 15 anthropogenic stressors and also a very low combined cumulative impact from these stressors. We discover that ∼13% of the ocean meets this definition of global wilderness, with most being located in the high seas. Recognizing that human influence differs across ocean regions, we repeat the analysis within each of the 16 ocean realms [ 15 ]. Realm-specific wilderness extent varies considerably, with >16 million km 2 (8.6%) in the Warm Indo-Pacific, down to <2,000 km 2 (0.5%) in Temperate Southern Africa. We also show that the marine protected area estate holds only 4.9% of global wilderness and 4.1% of realm-specific wilderness, very little of which is in biodiverse ecosystems such as coral reefs. Proactive retention of marine wilderness should now be incorporated into global strategies aimed at conserving biodiversity and ensuring that large-scale ecological and evolutionary processes continue. Video Abstract [ABSTRACT FROM AUTHOR]