Individual study: Population monitoring and recovery of the northern leopard frog (Rana pipiens) in southeast British Columbia. Report to the Columbia Basin Fish and Wildlife Compensation Program
Adama D.B. & Beaucher M.A. (2006) Population monitoring and recovery of the northern leopard frog (Rana pipiens) in southeast British Columbia. Report to the Columbia Basin Fish and Wildlife Compensation Program.
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Head-start amphibians for release
A replicated study in 2000–2005 at two wetlands in British Columbia, Canada (Adama & Beaucher 2006) found that captive-reared and released northern leopard frog Rana pipiens tadpoles and metamorphs survived over winter and bred successfully. At one site, seven juveniles, three adults and 13 unmarked young of the year were recorded the year after release. At the other site three egg masses and numerous young-of-year were recorded in one area, but no frogs were caught in the second area. In 2005, population estimates for young of the year/site were 1,361 and 3,874 respectively. Wild young were significantly larger than captive-reared young in all but two years (13 vs 8 g). Average survival in captivity was 82%. An increased protein diet resulted in increased size at metamorphosis and decreased time to metamorphosis (reduced 75 days). In 2001–2005, 30,065 hatchlings from 27 egg masses were collected and reared in captivity. In total, 10,147 tadpoles and 14,487 metamorphs were marked and released back to the source population and at two restoration sites. Monitoring was undertaken using visual encounter and call surveys.