Type: report

Article abstract: During the 2001 Arroyo Toad Surveys by USGS, arroyo toads were observed at five of the twelve study sites. Arroyo toads were observed in the months of May, June and July. The timing of the detectability of the arroyo toads appears to vary between sites. Most notable is the delayed timing of the Deep Creek population of arroyo toads. While arroyo toads were observed at five other localities in the SBNF during the month of May, the first detected arroyo toad from Deep Creek Hot Springs was from mid-June. Furthermore, the arroyo toads in Deep Creek Hot Springs became more detectable by mid-July. The lower Mojave River populations appear to have the earliest timing as detected from the 2001 surveys. Larvae were present upstream from the Mojave Forks Dam in the West Fork of the Mojave River from early May. Adults were also detected during May in this location as well, with only one adult being detected in Mojave Forks Dam vicinity in the month of June. The Little Horsethief Canyon population of arroyo toads appears to be timed in between the lower Mojave River populations and the populations higher in Deep Creek. During early May, arroyo toads in Little Horsethief Canyon were observed breeding. By the end of May, several adult arroyo toads were observed as well as some larvae. Metamorphic arroyo toads were observed at Little Horsethief Canyon by the middle of June. The timing of the Bautista Canyon arroyo toads is unclear. Adult arroyo toads were observed in Bautista Canyon during the months of May and June, however no indication of breeding behavior or recruitment was observed. More 20 surveys from throughout the late winter and early spring are needed to determine the timing and location of breeding events in this population of arroyo toads. The populations of arroyo toads in the Mojave River, Deep Creek Hot Springs, Little Horsethief Canyon and Bautista Canyon appear to be relatively substantial populations based on their detectability in 2001. Some segments of the Mojave River population appear to be impacted as lower detectability is correlated with disturbance and habitat conversion (OHV usage and beaver ponds) in specific localities. Other populations of arroyo toads in and near the SBNF (Cucamonga, Cajon Wash, Whitewater) are located in areas that appear to be more heavily impacted with less continuous overall suitable habitat than the areas where arroyo toads were observed in 2001. These less detectable populations sho