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Hamilton et al. 2010 - Biological Conservation.pdf (411.48 kB)

Factors associated with survival of reintroduced riparian brush rabbits in California

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posted on 2020-09-18, 00:50 authored by L Hamilton, P Kelly, D Williams, D Kelt, Heiko WittmerHeiko Wittmer
The riparian brush rabbit (Sylvilagus bachmani riparius) is an endangered species found in dense, brushy habitat in the California's Central Valley. We implemented a reintroduction program to bolster populations at a Federal Wildlife Refuge and to assess factors influencing mortality and subsequent survival of released individuals. Between July 2002 and July 2005, we reintroduced 325 captive-bred individuals to unoccupied habitat within their historic range using a soft-release strategy and monitored their subsequent survival with radiotelemetry. Longer time in soft-release pens resulted in increased monthly survival. Rabbits were most susceptible to post-release mortality during the first 4 weeks following reintroduction and both body mass and length of time in the soft-release enclosure influenced this relationship. When we controlled for release mortality during this acclimation period, subsequent monthly survival probabilities were most strongly influenced by release year (year 1 vs. years 2 and 3) and by a catastrophic flooding event; length of time in the soft-release enclosure remained an important variable in longer-term survival. Cause of mortality was unknown for the majority of deaths (61.9%), but predation (including presumptive predation) was the greatest known cause of death in translocated rabbits (26.4%). Reintroduction programs should employ an adaptive management approach with ongoing monitoring of target animals and concurrent analysis to allow managers to adjust methods as conditions dictate. © 2010 Elsevier Ltd. All rights reserved.


Preferred citation

Hamilton, L., Kelly, P., Williams, D., Kelt, D. & Wittmer, H. (2010). Factors associated with survival of reintroduced riparian brush rabbits in California. Biological Conservation, 143(9-14 November), 999-1007.

Journal title

Biological Conservation




9-14 November

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Elsevier BV

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