Histograms of 24 absolute values for each testing method.

<p>Method 1- incidental representation measuring median target achievement; method 2- incidental representation measuring percentage of features with targets fully met; method 3- species accumulation index measuring median target achievement; method 4- species accumulation index measuring percentage of features with targets fully met; and method 5- correlation of summed irreplaceability values.</p

Mean rankings of test feature groups (with 95% confidence intervals).

<p>A rank of 1 indicates highest surrogate effectiveness and 5 indicates lowest. Results are grouped across (a) all tests, (b and c) two study areas, (d and e) both surrogates and (f–j) each method. Method 1- incidental representation measuring median target achievement; method 2- incidental representation measuring percentage of features with targets fully met; method 3- species accumulation index measuring median target achievement; method 4- species accumulation index measuring percentage of features with targets fully met; and method 5- correlation of summed irreplaceability values.</p

Summary of all results, showing effectiveness estimates (absolute values) arranged by study area and testing method.

<p>Note that absolute values are not comparable between testing methods. Asterisks indicate significance levels (*** p<0.001; ** p<0.01; and * p<0.05) for comparisons of the surrogate's effectiveness versus a null-distribution of randomly selected areas (for methods 1–4) randomly paired planning units (for method 5). Method 1-incidental representation measuring median target achievement; method 2- incidental representation measuring percentage of features with targets fully met; method 3- species accumulation index (SAI) measuring median target achievement; method 4- species accumulation index (SAI) measuring percentage of features with targets fully met; and method 5- correlation of summed irreplaceability values.</p

Relationships between effectiveness estimates from five alternative testing methods.

<p>Effectiveness values were ranked on their native scale for each method (for each method n = 24 based on different combinations of study area, surrogate, and test feature group) and compared using Spearman's rank correlation coefficient. Asterisks indicate significance levels (*** p<0.001; ** p<0.01; and * p<0.05).</p

A Hierarchical Classification of Benthic Biodiversity and Assessment of Protected Areas in the Southern Ocean

<div><p>An international effort is underway to establish a representative system of marine protected areas (MPAs) in the Southern Ocean to help provide for the long-term conservation of marine biodiversity in the region. Important to this undertaking is knowledge of the distribution of benthic assemblages. Here, our aim is to identify the areas where benthic marine assemblages are likely to differ from each other in the Southern Ocean including near-shore Antarctica. We achieve this by using a hierarchical spatial classification of ecoregions, bathomes and environmental types. Ecoregions are defined according to available data on biogeographic patterns and environmental drivers on dispersal. Bathomes are identified according to depth strata defined by species distributions. Environmental types are uniquely classified according to the geomorphic features found within the bathomes in each ecoregion. We identified 23 ecoregions and nine bathomes. From a set of 28 types of geomorphic features of the seabed, 562 unique environmental types were classified for the Southern Ocean. We applied the environmental types as surrogates of different assemblages of biodiversity to assess the representativeness of existing MPAs. We found that 12 ecoregions are not represented in MPAs and that no ecoregion has their full range of environmental types represented in MPAs. Current MPA planning processes, if implemented, will substantially increase the representation of environmental types particularly within 8 ecoregions. To meet internationally agreed conservation goals, additional MPAs will be needed. To assist with this process, we identified 107 spatially restricted environmental types, which should be considered for inclusion in future MPAs. Detailed supplementary data including a spatial dataset are provided.</p></div

Benthic ecoregions and their features (see Fig.2 for the location of each ecoregion).

<p>Benthic ecoregions and their features (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100551#pone-0100551-g002" target="_blank">Fig.2</a> for the location of each ecoregion).</p

Circumpolar datasets used within the classification.

<p>Circumpolar datasets used within the classification.</p

The benthic ecoregions, restricted environments and marine protected areas identified within the Southern Ocean.

<p>An environmental type is a unique combination of an ecoregion, bathome and geomorphic feature. Existing marine protected areas and regions where planning processes are underway to propose future representation, were identified. Where large gaps in existing and proposed representation were found, the locations of geographically restricted environmental types were identified. These restricted environments indicate areas of potential future marine protected area selection since there are limited spatial options for protecting the biodiversity for which these environments are a surrogate.</p

The geomorphic features of the Southern Ocean classified according to the attributes of the seabed surface substratum.

<p>The geomorphic features of the Southern Ocean classified according to the attributes of the seabed surface substratum.</p

Environmental types and the bio-physical data used to drive the classification.

<p><b>A)</b> The 562 environmental types (in colour) and ecoregion outlines (refer to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100551#pone-0100551-g002" target="_blank">figure 2</a> for names) broadly reflect the underlying data used within the classification <b>B)</b> Bathomes derived from bathymetry and species-depth relationships <b>C)</b> Geomorphic features; Abyssal Plain (1), Bank (2), Canyon (3), Cliff (4), Coastal (rugged) Terrane (5), Contourite Drift (6), Cross Shelf Valley (7), Fracture Zone (8), Island Arc (9), Island Coastal Terrane (10), Lower Slope (11), Marginal Ridge (12), Marginal Plateau (13), Mid-Ocean Ridge Rift Valley (14), Ocean Trough (15), Plateau (16), Plateau Slope (17), Ridge (18), Rugose Ocean Floor (19), Seamount Ridges (20), Seamount (21), Shelf (22), Shelf Deep (Depressions) (23), Structural Slope Region (24), Trench (25), Trough Mouth Fans (26), Upper (Continental) Slope (27), Volcano (28) <b>D)</b> Seabed temperature <b>E)</b> Duration of the year where more than 85% of the region is covered by sea ice <b>F)</b> High positive and negative values indicate areas of consistently high and low summer productivity respectively. Values approaching zero indicate areas that vary greatly between years.</p