An investigation into the use of road drainage structures by wildlife in Maryland.

PDFTech ReportMD-11-SP909B4MPhase I: SP808B4QPhase II: SP909B4MWildlife crossingsCulvertsMarylandMaryland. State Highway Administration. Office of Policy & ResearchSparks, James L.Gates, J. EdwardUniversity of Maryland Center for Environmental Science. Appalachian LaboratoryMaryland. State Highway Administration. Office of Policy & ResearchUS Transportation CollectionThe research team documented culvert use by 57 species of vertebrates with both infra-red motion detecting digitalgame cameras and visual sightings. Species affiliations with culvert characteristics were analyzed using \ucf\u20212statistics, Canonical Correspondence Analysis (CCA), ANOVA, and t-tests for 12 species (northern raccoon,Virginia opossum, domestic cat, woodchuck, great blue heron, red fox, humans, white-tailed deer, gray squirrel,Norway rat, gray fox, and white-footed or deer mouse) that occurred in more than 30 culverts. Culvert width andlength were the most important variables according to CCA. Nearly all of these 12 species exhibited greater use ofculverts with lower mean water depth, except for great blue heron, which used culverts that had deeper water (P =0.014) more frequently. White-tailed deer (n = 1,903 in 63 culverts) were not strongly associated with a particularculvert shape (\ucf\u20212 = 5.589, 2 df, P = 0.061) or substrate type (\ucf\u20212 = 7.462, 5 df, P = 0.188). White-tailed deer usedculverts less often when there was no fence on either side of the highway (\ucf\u20212 = 26.491, 5 df, P < 0.001). Thenumber of road-killed deer was generally less in areas receiving high use of culverts by deer, although there werenotable exceptions. White-tailed deer used culverts in the Maryland Piedmont region more frequently (F[3, 261] =5.995, P = 0.001). Northern raccoons were the most prevalent species in the camera survey, occurring in 246 ofthe 265 (93%) sampled culvert cells. Green frogs were the most abundant herptile species, sighted in 38 culverts.Box culverts were the most frequently used type of culvert for nest building by both barn swallow (\ucf\u20212 = 7.474, 1df, P = 0.006) and eastern phoebe (\ucf\u20212 = 18.292, 1 df, P < 0.001). Our results can be used to better design orretrofit culverts to improve wildlife-habitat connectivity and reduce wildlife-vehicle collisions