Responses of Small Terrestrial Vertebrates to Roads in Coastal Sage Scrub Ecosystem
I assessed the activity pattern of small mammals and lizards in relation to three types of roads transecting coastal sage scrub habitats. The bulk of data were generated for three small mammal species (Chaetodipus fallax, Peromyscus eremicus, and Peromyscus maniculatus) and two lizard species (Sceloporus occidentalis and Cnemidophorus hyperythrus). I characterized both relative abundance at two distances from each road and individual movement patterns in relation to each road in order to explore the effects of roads on species spatial and movement dynamics. The two habitat specialists exhibited decreased abundance next to different road types. The three habitat generalists either showed no difference or increased abundance by a road. These data generally support previous studies that suggest habitat specialists are more sensitive to edges. All species exhibited decreased permeability to improved roads. The unimproved dirt road did not impede movement, while the primary highway was a barrier for all species. Responses to the secondary paved road differed among species. I suggest that species with open microhabitat preferences are more likely to venture out onto unimproved dirt and secondary paved roads. Those that did venture out onto improved roads suffered increased mortality due to vehicular traffic.