Demographic consequences of heavy metals and persistent organic pollutants in a vulnerable long-lived bird, the wandering albatross

Abstract

Seabirds are top predators of the marine environment that accumulate contaminants over a long life-span. Chronic exposure to pollutants is thought to compromise survival rate and long-term reproductive outputs in these long-lived organisms, thus inducing population decline. However, the demographic consequences of contaminant exposure are largely theoretical because of the dearth of long-term datasets. This study aims to test whether adult survival rate, return to the colony and long-term breeding performance were related to blood mercury (Hg), cadmium (Cd) and persistent organic pollutants (POPs), by using a capture-mark-recapture dataset on the vulnerable wandering albatross Diomedea exulans. We did not find evidence for any effect of contaminants on adult survival probability. However, blood Hg and POPs negatively impacted long-term breeding probability, hatching and fledging probabilities. The proximate mechanisms underlying these deleterious effects are likely multifaceted, through physiological perturbations and interactions with reproductive costs. Using matrix population models, we projected a demographic decline in response to an increase in Hg or POPs concentrations. This decline in population growth rate could be exacerbated by other anthropogenic perturbations, such as climate change, disease and fishery bycatch. This study gives a new dimension to the overall picture of environmental threats to wildlife populations.

Seabirds and climate: knowledge, pitfalls, and opportunities

“…These authors had a very detailed demographic data-set that is not always available in conventional studies, but these types of confounding biotic factors (i.e., age, sex) that should be taken into account when studying the effect of climate on seabird populations. An increasing number of studies showed that the effects of climate factors or pollutants on demographic parameters are state dependent (Nevoux et al, 2010a;Goutte et al, 2014). This also matches with life history theory since energetic costs and metabolism differ between breeding and nonbreeding individuals, which may in turn affect their demographic performance.…”

Rapidly increasing methyl mercury in endangered ivory gull ( Pagophila eburnea ) feathers over a 130 year record

“…Individual wandering albatrosses (Diomedea exulans) with higher blood Hg were less likely to breed, their eggs less likely to hatch and their chicks less likely to fledge [72], and clapper rails' (Rallus longirostris) body condition was negatively related to blood and feather Hg concentrations [73]. Declining populations of rusty blackbirds (Euphagus carolinus) tend to have higher blood and feather Hg than other populations [74], and several species within a songbird community more than 100 km downstream from an historical Hg point source had Hg concentrations of concern [75].…”

Trophic ecology drives contaminant concentrations within a tropical seabird community

“…Further, despite in Catry et al (2008) Hg analyses were performed using whole blood, which reflects relatively similar concentrations than that of red blood cells, Hg concentrations in the Brown noddy were much lower than those of French Guiana (Catry et al, 2008). Similar Hg concentrations have been previously associated with deleterious effects (Costantini et al, 2014;Tartu et al, 2016) with consequences at the population level such as reduction of breeding, hatching and fledging success, and population decline (Goutte et al, 2014a(Goutte et al, , 2014b. Finally, as compared to other seabirds exposed to POPs, our results revealed concentrations of thousand times lower than those associated with deleterious effects (Erikstad et al, 2013;Goutte et al, 2015), which very likely do not pose a health threat to this seabird community.…”