Fig 1.
Landcover data (a) [44] and roadways classified into six general categories (b) in Vermont, USA.
We focused our analysis on 5,912 state-managed transportation structure locations on the Interstate System and State Road System (c).
Table 1.
Landcover and road class variables used to develop landscape scale and structure scale resistance layers for 8 wildlife species in Vermont, USA. Landcover in the buffered analysis area within Québec, Canada used variables from the North American Land Change Monitoring System (NALCMS) dataset, and these variables were reclassified as comparable US National Land Cover Dataset (NLCD) variables; attribute names from original datasets shown.
Table 2.
Resistance values for landscape variables in the landscape scale and structure scale analyses by species. Expert opinion values for each species were elicited through an online survey and follow-up interview with expert scores for each variable averaged together. Scores ranged from 1 indicating no resistance to 100 indicating complete resistance and ‘null’ for impermeable.
Table 3.
Average home range size of each focal species used to determine the moving window size in landscape scale Omniscape analyses.
Table 4.
Electrical current density summary statistics (in amps of electricity) for each species at the landscape scale (calculated from the statewide maps within 1 km radius of all structures), and among all transportation structure locations (calculated within the 50 m radius of all structures) at the structure scale.
Fig 2.
Maps of predicted wildlife movement throughout Vermont from Omniscape analyses.
Areas of high electrical current density represent areas of more concentrated expected species movement.
Table 5.
Spearman’s rank correlations assessing the relationship between the four methods of transportation structure rankings. Percent of overlapping sites between ranking methods indicated in parentheses.
Fig 3.
The top-ranking 100 roadway structures from four ranking methods.
Structures were ranked from highest mean current density to lowest in each method. Method 1 considered landscape scale flow, Method 2 considered structure scale flow, Method 3 considered landscape and structure scale flow, and Method 4 used a Rarity-Weighted Richness Index (RWRI) to rank structures.