Using expert elicitation to rank ecological indicators for detecting climate impacts on Australian seabirds and pinnipeds

Abstract

Designing monitoring programs to detect impending climate change effects on marine vertebrates is challenging, as data sufficient for large-scale power analysis is severely limited, yet sensitivity and response time of potential indicator variables are key uncertainties. In the absence of such data, the experience of researchers can be used to inform decision making on monitoring design to detect impacts of climate change. We used expert elicitation to identify ecological traits of seabirds and marine mammals that have or were expected to respond to climate change. We analyzed the projected biological changes for five general categories of ecological traits that have been shown elsewhere to relate to climate signals: foraging and diet, body mass, breeding phenology, breeding success, and population size. Based on analysis of 106 traits in the five categories, 29 experts rated foraging- and diet-related traits to be the most responsive to climate change, although predictions for traits in this category were also the most variable across experts. Body mass related traits were projected to change almost as frequently, but with much lower variance. The timespan over which experts expected to see change also varied between trait categories. Foraging success was expected to respond most quickly. Considering sensitivity and response rate, we predict that the duration of foraging trips will be the best climate change indicator among the 106 traits. When combined with cost estimates, our results allow managers to choose ecological indicators that deliver information on system response in the most cost-effective manner.