Contemporary effective population size and predicted maintenance of genetic diversity in the endangered kea (<i>Nestor notabilis</i>)

<p>Population size and the potential for maintenance of genetic diversity are critical information for the monitoring of species of conservation concern. However, direct estimates of population size are not always feasible, making indirect genetic approaches a valuable alternative. We estimated contemporary effective population size (<i>N</i>_e) in the endangered kea (<i>Nestor notabilis</i>) using three different methods. We then inferred the census size (<i>N</i>_C) using published <i>N</i>_e/<i>N</i>_C ratios and modelled the future maintenance of genetic diversity assuming a number of demographic parameters. Short-term <i>N</i>_e was small with a range-wide <i>N</i>_e < 250–700, while <i>N</i>_C was within the range of the current estimate (c. 1000–5000). Forward simulations showed low probability of retaining 90% of rare alleles without immigration. However, the probability of maintaining genetic diversity was high with immigration, juvenile survival of ≥ 30%, and an initial sex ratio of c. 0.5–0.6. Despite the low <i>N</i>_e in kea, predator control and/or artificial immigration might be sufficient to maintain the present genetic diversity.