In March 1999, we selected starting points for each point count transect. In June 1999, we completed laying out the remainder of each transect. To mark each transect, we used a measuring tape and a compass to walk a straight course for 250-300 m from the chosen starting point. At the end point, the map was checked to verify that the location was correct by referencing recognizable landmarks such as fence lines, road intersections, and topography. We then marked each point with a wooden stake and plastic tag on which the transect name and point number were written. A non-differentially corrected GPS fix was obtained for each point to facilitate relocating the points even if the stakes are removed.
Habitat Characteristics Basic habitat structural characteristics were recorded in the spring at all point count locations, and on each small mammal plot and transect. Since each small mammal plot was more or less homogeneous in habitat structure and was selected to represent a larger and frequently occurring plant community, we recorded habitat structural characteristics at a random location within the plot, avoiding the plot boundaries. The following information was recorded: general plant community, percent canopy closure, maximum vegetation height (MVH), percent ground cover/type, an index of visual obstruction (VO), and general comments about the immediate area, including the number of junipers >10 cm dbh in the area. The general plant community, percent canopy cover, height of dominant vegetation, percent ground cover, and juniper counts were estimated for the area within a 25-m radius of the sample point. In open areas where large trees remained outside of the 25-m radius, but obviously influenced the character of the site, both shrub height and adjacent tree height were recorded. Visual obstruction, or horizontal shrub cover, was estimated using a Nudd’s board, after the methods of Griffith and Youti (1988). The device consisted of a white panel, 60-cm wide x 200-cm high, with 50-cm partitions inscribed horizontally on the face. The board was observed from a distance of 10 m and the percent of each 50-cm panel partition that was concealed by vegetation was recorded. The procedure was repeated for three bearings at 90E intervals and the values averaged. Care was taken to not walk along the site line thus influencing the density of horizontal cover prior to measurement. A general assessment was also made as to the type of concealment encountered, i.e., grass, shrubs, tree branches, stumps, etc. We also conducted vegetation surveys along each VES 500-m line-transect for reptiles to characterize dominant vegetation (trees and shrubs) and general ground cover estimates within shrub-steppe habitats. Habitat variables were recorded during installation of transects. A total of 6 points were sampled along each 500-m line transect (Meter Points 0, 100, 200, 300, 400, 500). We recorded dominant tree and shrub species, and visually estimated average vegetation height in a 50-m radius around each point. We also visually estimated ground cover in a 10-m radius around each point.