Linear (top) and non-linear (bottom) versions of resistance surfaces based on wildness (left) and human modification (right) used to model connectivity between large protected areas.

<p>See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0154223#pone.0154223.s001" target="_blank">S1 Fig</a> for distribution of resistance surfaces in relation to original indices.</p

Map of the contiguous United States showing large core protected areas and Protected Areas Database of the U.S. units not included in our definition of core protected areas.

<p>Map of the contiguous United States showing large core protected areas and Protected Areas Database of the U.S. units not included in our definition of core protected areas.</p

Composite corridor value between large protected core areas, which was calculated by summing and reclassifying normalized least-cost corridors shown in Fig 3.

<p>Black polygons are large core protected areas used in our analysis. Raster data are available as <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0154223#pone.0154223.s006" target="_blank">S1 File</a>.</p

Normalized least cost corridors (after removing the linkages >300 km shown in S3 Fig and the 10% worst linkages shown in S4 Fig) from Linkage Mapper connectivity models based on linear (left) and non-linear (right) versions of resistance surfaces using wildness (top) and human modification (bottom).

<p>Normalized least cost corridors (after removing the linkages >300 km shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0154223#pone.0154223.s003" target="_blank">S3 Fig</a> and the 10% worst linkages shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0154223#pone.0154223.s004" target="_blank">S4 Fig</a>) from Linkage Mapper connectivity models based on linear (left) and non-linear (right) versions of resistance surfaces using wildness (top) and human modification (bottom).</p

Mean composite corridor values (classified into deciles) among non-core Protected Area Database land units (A) and federal inventoried roadless and wilderness study areas (B).

<p>Roadless and wilderness study areas are shown in greater detail for the Northern Rockies and Southern Appalachian Mountains.</p