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

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.

Assessing the risks of changing ongoing management of endangered species

“…In our case, prior to the experiment, managers and experts were uncertain about the differences between status quo and sugar water. The sugar water option was considered because experience with other species suggested it might perform reasonably well (Chauvenet et al, 2012), but the exact outcome for olive white-eyes remained uncertain. This uncertainty complicated a decision and encouraged an empirical comparison of the two actions.…”

“…A longer study could have provided more reliable estimates of survival and fecundity, but implementing multiple feeding regimes was perceived as excessively risky and expensive. It is probably common for managers to consider it too risky to manipulate small populations of endangered species Canessa et al, 2019). However, experimental and adaptive management approaches can account for this risk to ensure the benefits of learning outweigh risks in the long term (Runge, 2011).…”

A Cause for Alarm: Increasing Translocation Success of Captive Individuals Through Alarm Communication

“…The most successful case studies of releases of captive-born individuals are associated with suitable predator control insitu (Short, 2004). Appropriate methods aim to slow down or reduce the intensity of predation by releasing individuals into predator-free areas, predator-proof habitats, or areas affected by predator removal (Griffin et al, 2000;Canessa et al, 2019). Many examples are seen in Australia, a country with particularly high rates of reintroduction failure (56%) compared to the rest of the world, linked to a high number of feral predators (Fischer and Lindenmayer, 2000).…”

“…On top of that, strategies to maintain predator awareness behaviors of released populations in predator-free areas must be implemented (Jolly et al, 2018). Predator-proofing of specific sites, for example using artificial nests or burrows, may target only one predator type and released individuals may ignore designated nests or burrows (Canessa et al, 2019). Culling predators can improve release survival outcomes in the short term (Fulton and Ford, 2001) but requires multiple considerations including: the protected status of the predator(s); compliance to ethical standards; communicating methods publicly for community understanding and approval; culling a justified number of predator individuals to secure the effectiveness of translocation; assessing opportunities for other predators in response to culling; and estimating the time for immigration and re-population of predators in the area.…”

Defensible management decisions to overcome action paralysis in the face of uncertainty

“…Our own experience working on some of Australia's most threatened birds has highlighted that risk aversion is a pervasive issue in many conservation programmes (Canessa et al, 2020;Stojanovic et al, 2018). Conservation managers often suffer action paralysis to avoid potential blame for exacerbating population declines or jeopardizing population recovery, if management decisions produce perverse outcomes (Meek et al, 2015).…”