Captive breeding and reintroduction evaluation criteria: a case study of peninsular bighorn sheep

Captive breeding and reintroduction programs are rarely evaluated, and asse ssment criteria vary widely. We used the following criteria to evaluate a b ighorn sheep (Ovis canadensis) augmentation program: (1) survival and recru itment rates in the captive population, (2) survival of released animals, ( 3) recruitment of released animals (4) growth rate of the reintroduced or a ugmented population, and (5) establishment of a viable wild population. Cap tive bighorn survival and recruitment was high, averaging 0.98 (SD = 0.05) and 71.0% (SD = 19.4), respectively. Annual survival of free-ranging captiv e-reared bighorn (n = 73, (x) over bar = 0.80 SD = 0.11) did not differ (Z = -0.85, p = 0.40; n = 14) from survival of wild-reared bighorn (n = 43, (x ) over bar = 0.81, SD = 0.12). Recruitment was unusually low for both capti ve-reared ((x) over bar = 13.7%, SD = 0.24) and wild-reared ewes ((x) over bar = 13.7%, SD = 0.20). Although reintroduction did not result in populati on growth or establishment of a viable population, it helped prevent extirp ation of the reinforced deme, preserved metapopulation linkage, and aided h abitat preservation. Chronic low recruitment and low adult survivorship pre cluded achievement of criteria 3-5. Environmental conditions in the release area also appeared to hinder program success. Standard evaluation criteria for ongoing reintroductions allow for informative assessments and facilita te comparisons needed to refine reintroduction science as a recovery tool f or threatened or endangered populations.