Transect Survey - Mojave Desert - 2017 - Terrestrial Species Stressor Monitoring [ds2834]

Visual Encounter Transect Surveys of reptiles, amphibians, and other vertebrate wildlife taxa were conducted at a subset of study sites in the Mojave Desert in 2017. A total of 52 transect surveys at 17 study sites were conducted between March and June 2017. For each survey, a single observer walked two 200-meter transects and recorded counts and distances of all wildlife observed. The two transects are laid out as a cross intersecting at a right angle, with this intersection occurring at survey site center. The exact orientation of the cross and the sinuosity of transects was left to the discretion of the surveyor(s) to optimize sampling of the site-designated lifeform and to facilitate ease of travel (e.g., barriers or steep slopes). In the case of a riparian lifeform site, one transect was aligned along or near the stream course, and the second along the gradient extending to either side of the stream course. In the case of a guzzler or wetland, transects were aligned along approximately perpendicular sides. A laser rangefinder was used to accurately measure the perpendicular distance from the transect to the location of each wildlife group at the instance of its initial observation. These data were used for distance sampling methods to estimate abundance, and for comparing 2016 and 2017 data. Whenever possible, these transect surveys overlapped spatially with Time Constrained Searches at the same location.