Individual study: Reintroducing endangered Vancouver Island marmots: survival and cause-specific mortality rates of captive-born versus wild-born individuals
Aaltonen K., Bryant A.A., Hostetler J.A. & Oli M.K. (2009) Reintroducing endangered Vancouver Island marmots: survival and cause-specific mortality rates of captive-born versus wild-born individuals. Biological Conservation, 142, 2181-2190
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Release captive-bred individuals to re-establish or boost populations in native range
A replicated study in 2003–2007 at two mountain sites on Vancouver Island, Canada (Aaltonen et al. 2009) found that released captive-born Vancouver Island marmots Marmota vancouverensis had lower annual survival rates than wild-born marmots, and those released at two years old were more likely to survive than those released as yearlings. The average annual post-release survival rate of captive-bred marmots (61%) was lower than that of wild-born marmots (85%). Captive-bred marmots released at the age of two or more years had higher annual survival rates (77%) than those released as yearlings (60%). In 2003–2007, ninety-six captive-born Vancouver Island marmots were released at two sites. The released marmots were radio-tagged and monitored for a total of 154 marmot-years (one marmot-year represents one record/marmot/year). Wild-born marmots (number not reported) were also radio-tagged and monitored for 101 marmot-years in 2003–2007. All radio-tagged marmots were tracked from the ground or from a helicopter. Monitoring frequency is not stated.
(Summarised by Ricardo Rocha)