Assessing the effect of predator control on an endangered goose population subjected to predator-mediated food web dynamics

1. Assessing the effectiveness of conservation actions to halt population declines is challenging when confounded by other factors. We assessed whether culling of red fox, a predator currently increasing in the sub-Arctic, contributed to recent recovery of the critically endangered Fennoscandian population of Lesser White-fronted Goose Anser erythropus, while controlling for potentially confounding food web dynamics.
2. Using 19 years of data, 10 before and 9 after the implementation of annual red fox culling, we estimated the effect of this action on annual performance of the goose population. We corrected for the potentially confounding effects of cyclic rodent dynamics and semi-domestic reindeer carrion abundance, both of which are expected to trigger predator functional and numerical responses, as well as for annual variation in spring phenology.
3. Goose reproductive success fluctuated in synchrony with the rodent cycle and was negatively related to abundant carrion. When account...