Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
2016 Season Summary: Foothill Yellow-Legged Frog Docent Program Elizabeth Ruiz, Watershed Stewards Program The only true frog in western North America to breed exclusively in streams 1, the Foothill Yellow-Legged Frog (Rana boylii), has seen a large decrease in population numbers and range over time. Its status as a federal “sensitive species” is currently under review by US Fish and Wildlife 2, though it is currently “near-threatened” according to the International Union for Conservation of Nature (IUCN) and a “species of special concern” in the state of California. Historically found in Oregon, California, and western Mexico, the foothill yellow legged frog (FYLF) has lost approximately 45% of its range in California alone. Invasive species, stabilization of seasonal stream flows, recreation, and habitat loss have all contributed to the decline of the species.3 Within the Mt. Tamalpais watershed, there are two small, yet stable, populations of FYFL, both of which are threatened by visitor usage, particularly at Little Carson Falls. Visitation to the falls jumped in popularity in the early 2000’s, turning what was a frog sanctuary into a heavily trafficked hiking destination. The picturesque cascades and rocky pools, where the FYFL lay their eggs, are alluring to hikers, and occasionally their dogs, who wish to cool off with a swim. Managed by the Marin Municipal Water District (MMWD), and almost completely within the boundaries of the Mt. Tamalpais State Game Refuge, the trails leading to the falls are some of many open to recreationalists from all over the San Francisco Bay region. In an effort to raise awareness about the breeding site at Little Carson Falls, and to balance increased traffic, visitor enjoyment, outreach, and FYLF protection, MMWD established the Frog Docent Program in 2005. Volunteers are recruited, trained on FYLF life history and visitor interaction, and spend weekends during the March-June breeding period at the falls, educating visitors about frogs and watching out for harmful behavior. Spotted! FYFL and egg mass. Photo: Sari Kwan The February 27th training was attended by 17 people, and the volunteer pool for the season was 13, which included five new docents and eight returners. Following an introduction to the program, Garcia and Associates (GANDA) herpetologist Joe Drennan lead a section on frog biology, and ranger John 1 Worley Firley, Stephanie. "Is the Foothill Yellow-Legged Frog in Hot Water – Because of Cold Water?"US Forest Service. USFS Pacific Southwest Research Station 29 Apr. 2015 2 "Species Profile for Rana Boylii." Environmental Conservation Online System. US Fish and Wildlife Service 3 "Foothill Yellow-legged Frog - Rana Boylii." California Herps. California Herps. 1 McConneloug trained the group in safety, radio use protocols, and successful interactions with the public. The second half of the training included a hike to the falls from the Azalea Hill Trailhead, where we observed several frogs basking in the upper pools, allowing practice with the spotting scopes. Weekends were grey and rainy until mid-March, and when the weather began to get a little nicer the docents began filling up shifts. The weather stayed warm and dry for the rest of the season, through Memorial Day, which marked the end of the season on May 30th. Over the course of the season the 13 docents dedicated a total of 226.5 hours to the protection of the frogs! An increase from last year, and 20 hours shy of 2014’s record. Docents covered 63% of the 56 total weekend shifts, either morning (9am-1pm) or afternoon (1-5pm), and 86% of the 28 possible volunteer days. The number of shifts covered is slightly higher than last year’s 58% coverage rate, though the percentage of days covered is very similar. This year was a unique one for the docent program. On March 14th a landslide closed a portion of the Fairfax-Bolinas road and blocked access to Cataract Falls, another popular hiking destination. Hikers instead appeared to visit Little Carson in droves. Visitor usage was so high the docents requested additional volunteers for the afternoon shifts, and throughout the covered shifts docents encountered a total of 1636 individual visitors, almost 600 more than the previous record in 2010. Due to the fact that there are no docents during the week, we have no visitor usage numbers for weekdays. Docents shared FYLF information with 85% of the visitors, for a whopping total of 1393 individuals. They observed 19 people in the pools, and while that is more than three times the previous total, that number accounts for 1% of the total traffic this season. More than 150 of our fourlegged friends enjoyed a hike to the falls as well, and of those, only three were observed in the water, though GANDA biologists recorded disturbance to egg masses by dog 2 presence in the pools. Following this observation, MMWD maintenance and resource staff removed a social trail leading to the pools by covering it with brush and blocking it with heavy logs. Almost all of the visitors to the falls leashed their dogs or removed themselves from the water upon request, and docents recorded only two negative reactions for the season, which were expertly handled by the volunteers. FYFL amplexus Photo: Fair Family Swimming away post-survey Photo: E. Ruiz In addition to educating watershed visitors, docents also make observations of the frogs and other wildlife. This season there were 128 frog sightings, including observations of amplexus (mating). Additionally, volunteers observed a host of other wildlife, from garter snakes, newts, tadpoles, and dragonflies, to hummingbirds, towhees, nuthatches, and even a bald eagle. The data collected by docents are particularly useful for GANDA biologists when deciphering signs of damage or predation to egg masses. Surveys conducted by Garcia and Associates yielded observations of 45 adult males, at least 10 female frogs, and 13 egg masses at Little Carson Falls. The season total for the number of egg masses observed on the tributaries and mainstem of Big Carson in addition to the 13 at Little Carson was 41, the highest number recorded since surveys began in 2005. The highest number of egg masses observed prior to this year was 38 in 2012. Breeding season was longer than usual, with the last egg mass observed on May 26th in the Big Carson system. To date, volunteers with the frog program have dedicated more than 2500 hours to the protection of the frogs and the education of watershed visitors. They’ve informed 6156 individuals about the plight and conservation of the FYLF. The docents are vital in ensuring that all watershed residents and visitors can enjoy the natural resource. We are immensely appreciative of our 2016 docents: Maria Melendez-Martinez, Cindi Darling, Peter Suri, Frederic Leist, Sari Kwan, Janet Bodle, Lorri Gong, Lindsey Going, Jim Garlock, Rich Crimino, Harold Hirsch, Rob Ruiz, Bill Bain, James Fair, and our youngest docent in history, Ethan Fair. Thanks to all of you for your time and support! 3