Multiple stressors: modeling the effect of pollution, climate, and predation on viability of a sub‐arctic marine bird

Abstract

Negative effects of long‐transported pollutants, such as many persistent organic pollutants (POPs), on seabirds and other top predators have been documented for decades. Yet, the concentrations, and hence, the negative impacts of many POPs have recently declined in the Northern Hemisphere. However, organisms are exposed to multiple stressors and the impacts of pollution act in concert with both natural and other anthropogenic stressors. In theory, this means that even sub‐lethal POP concentrations may cause adverse effects if they co‐occur with increased levels of other stressors. We tested the multiple stress hypothesis on common eiders, a marine duck with a northern geographical distribution, by assessing the relative importance of pollution, climate (winter sea surface temperature; SSTw), and egg predation on population dynamics and viability (i.e., extinction risk) using Leslie‐matrix population models. The model was parametrized by estimating reproduction and apparent adult survival using long‐term data from a common eider population in sub‐arctic Europe. Average annual adult survival was 0.80 (coefficient of variation [CV] = 22.00%) and showed a negative, both direct and delayed, relationship with SSTw. Average clutch size was 4.41 eggs (CV = 5.12%) and varied in time showing periods of both positive and negative trends, but showed no relationship with SSTw. We based immature survival on estimates from literature: 0.52 and 0.68 for juveniles and yearlings, respectively. Our model supported the multiple stress hypothesis as changes in a single stressor did not induce extinctions, unless the magnitude of our manipulations was extreme except for egg predation. The effect of pollution was, however, increasingly negative when it co‐occurred with a warming climate and egg predation—and population viability was lowest when all the stressors occurred simultaneously.

Recent large-scale landscape changes, genetic drift and reintroductions characterize the genetic structure of Norwegian wild reindeer

“…Future studies should thus apply a multiple stressor approach (e.g. Munns Jr 2006;Bårdsen et al 2018) to population genetics. The point being that landscape changes, such as habitat loss and fragmentation, might mitigate or aggravate the effect of other on-going stressors affecting Norwegian wild reindeer.…”

Long‐term trends in the survival rates of adult female Common EiderSomateria mollissimaat three colonies in Iceland

“…(2012b) for the Baltic population between 1996 and 2010, and 80% reported by Bårdsen et al . (2018) for Norwegian birds between 1985 and 2015. However, it should also be noted that methodological differences could also have contributed to the differences in survival rates between these studies.…”

“…2017, Bårdsen et al . 2018, Dey et al . 2018) and outbreaks of disease such as cholera and Wellfleet Bay virus (Descamps et al .…”

Towards an urban marine ecology: characterizing the drivers, patterns and processes of marine ecosystems in coastal cities

“…wind-blown debris and dust) sources, pollution impacts marine life at individual, population and ecosystem levels, frequently bioaccumulating and then biomagnifying up the trophic pyramid (Erftemeijer et al 2012, Johnston et al 2015, Langston 2017. Chronic marine pollution effects tend to be sub-lethal (Browne et al 2015), but they can interact with other stressors in ways that ultimately cause mortality (Yaakub et al 2014a, Bårdsen et al 2018).…”