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

International audienceSeabirds 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

Early Life Nutrition and the Programming of the Phenotype

Early Life Nutrition and the Programming of the Phenotyp

Traffic noise decreases nestlings’ metabolic rates in an urban exploiter

International audienceHigh levels of anthropogenic noise produced in urban areas are known to negatively aff ect wildlife. Although most researchhas been focused on the disturbances of communication systems, chronic noise exposure can also lead to physiologicaland behavioural changes that have strong consequences for fi tness. For instance, behavioural changes mediated byanthropogenic noise (e.g. quality of parental care) may alter development and could infl uence nestling phenotype. Wetested if nestling metabolism was infl uence by traffi c noise in an urban exploiter, the house sparrow Passer domesticus .We experimentally exposed breeding house sparrows from a rural area to a playback of traffi c noise and we examinedthe impacts of this experimental procedure on metabolic rates and morphology of nestlings. We did not fi nd an eff ect oftraffi c noise on the morphology of nestlings. Surprisingly, we found that disturbed nestlings had overall lower metabolicrates and mass-adjusted metabolic rates than undisturbed birds. Our results suggest a specifi c eff ect of noise exposureper se, rather than an indirect eff ect of anthropogenic noise through the quality of parental care. Both the proximatemechanisms and the ultimate consequences of such metabolic changes on nestlings remain unknown and deserve futureexperimental studies

Mean ± SE (A) baseline and (B) stress-induced CORT levels of sparrows captured in 4 sites with different levels of urbanization.

<p>Sites are ordered from least to most urbanized (PC1 values) with two rural (CEBC and Villefollet) and two urban sites. Filled circles represent adults and open circles represent juveniles (n = 110, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135685#pone.0135685.t002" target="_blank">Table 2</a> for details). Differing letters indicate statistical difference between sites for both adults and juveniles (Tukey’s HSD test).</p

Habitat characteristics of the capture sites and sample sizes.

<p>Sites are listed in increasing order of urbanization (PC1 values from a principal component analysis conducted on the five habitat variables).</p><p>Habitat characteristics of the capture sites and sample sizes.</p

Mean ± SE (A) tarsus lengths and (B) body mass of sparrows captured in 4 sites with different levels of urbanization.

<p>Sites are ordered from least to most urbanized (PC1 values) with two rural (CEBC and Villefollet) and two urban sites. Filled circles represent adults and open circles represent juveniles (n = 110, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135685#pone.0135685.t002" target="_blank">Table 2</a> for details). Differing letters indicate statistical difference between sites for both adults and juveniles (Tukey’s HSD test).</p

Minimum adequate models when investigating the influence of capture site on several morphological parameters.

<p>Models were selected by using a stepwise approach starting from the full models (including site, age, sex, and interactions) and removing independent variables with P > 0.10.</p><p>Minimum adequate models when investigating the influence of capture site on several morphological parameters.</p

Mean ± SE (A) fat and (B) muscle scores of sparrows captured in 4 sites with different levels of urbanization.

<p>Sites are ordered from least to most urbanized (PC1 values) with two rural (CEBC and Villefollet) and two urban sites. Filled circles represent adults and open circles represent juveniles (n = 110, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135685#pone.0135685.t002" target="_blank">Table 2</a> for details). Differing letters indicate statistical difference between sites for juveniles only (A) or for both adults and juveniles (B) (Tukey’s HSD test).</p

Mean ± SE scaled mass index values of (A) adult and (B) juvenile sparrows captured in 4 sites with different levels of urbanization.

<p>Sites are ordered from least to most urbanized (PC1 values) with two rural (CEBC and Villefollet) and two urban sites. Filled circles represent adults and open circles represent juveniles (n = 110, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135685#pone.0135685.t002" target="_blank">Table 2</a> for details). The SMI did not significantly differ between sites as indicated by the similar letters (Tukey’s HSD test).</p