Transect Survey - 2016 - Terrestrial Species Stressor Monitoring [ds2833]

Visual Encounter Transect Surveys of reptiles, birds, and other vertebrate wildlife taxa were conducted at study sites in the Great Valley and Mojave Desert in 2016. A total of 1,856 transect surveys (GV: 517, MD: 1339) at 321 study sites (GV: 91, MD: 230) were conducted between March and July 2016. For each survey, observers walked two 200-meter transects and recorded counts of and distances to 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. The crew also noted all wildlife signs (tracks, scat, burrows, nests) observed; in particular, every scat group within a 1-m swath on either side of the transect wasnoted and identified by species whenever possible. All scats and tracks were removed from the swath so that return visits encountered fresh sign.Individual surveys focused on either reptiles and amphibians, or on birds and scat, but observations from all surveys were combined into this dataset. These data were used for distance sampling methods to estimate abundance.