摘要: |
The research team documented culvert use by 57 species of vertebrates with both infra-red motion detecting digital game cameras and visual sightings. Species affiliations with culvert characteristics were analyzed using oe2 statistics, 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 and length were the most important variables according to CCA. Nearly all of these 12 species exhibited greater use of culverts 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 particular culvert shape (oe2 = 5.589, 2 df, P = 0.061) or substrate type (oe2 = 7.462, 5 df, P = 0.188). White-tailed deer used culverts less often when there was no fence on either side of the highway (oe2 = 26.491, 5 df, P < 0.001). The number of road-killed deer was generally less in areas receiving high use of culverts by deer, although there were notable 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 of the 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 (oe2 = 7.474, 1 df, P = 0.006) and eastern phoebe (oe2 = 18.292, 1 df, P < 0.001). Our results can be used to better design or retrofit culverts to improve wildlife-habitat connectivity and reduce wildlife-vehicle collisions. |