Risk aversion and uncertainty create a conundrum for planning recovery of a critically endangered species

Abstract

Abstract Making transparent and rational decisions to manage threatened species in situations of high uncertainty is difficult. Managers must balance the optimism of successful intervention with the risk that intervention could make matters worse. We assessed nest protection options for regent honeyeaters (Anthochaera phrygia) in Australia. Formal expert elicitation highlighted two methods of nest protection expected to improve nest success. However, the risks and benefits of different actions were uncertain; for example, protecting nests from predators might also increase the risk of nest desertion by adults. To avoid risks, the recovery team opted to collect more information before implementation. The two methods of nest protection were compared using a field experiment. However, the same risk aversion limited the experiment to a single variable (nest predation) and dictated the use of artificial nests. The results of the experiment suggested neither action was likely to significantly reduce predation risks (<3% mean differences in survival between treatment and control). When presented with these results, managers made only minor revisions to their estimates; in part, this reflected low confidence by managers that artificial nests could reflect real predation risks. However, estimates were also revised more negatively for the initially less‐favored option, despite absence of such evidence, possibly highlighting confirmation bias. In this uncertain situation, the status quo was initially maintained although it was perceived as suboptimal; implementation of the preferred option (tree collars) is now planned for the 2019 breeding season. We faced what might be a common conundrum for conservation of critically endangered species. High uncertainty affects management decisions; however, perilous species status also leads to strong risk aversion, which limits both the willingness to act on limited information and the ability to learn effectively. Structured methods can increase transparency, facilitate evaluation, and assist decision making, but objective limitations and subjective attitudes cannot be circumvented entirely.

Keywords

• cognitive bias
• decision tree
• expert elicitation
• nest success
• predator control
• reintroduction