Seabirds reveal mercury distribution across the North Atlantic.

Mercury (Hg) is a heterogeneously distributed toxicant affecting wildlife and human health. Yet, the spatial distribution of Hg remains poorly documented, especially in food webs, even though this knowledge is essential to assess large-scale risk of toxicity for the biota and human populations. Here, we used seabirds to assess, at an unprecedented population and geographic magnitude and high resolution, the spatial distribution of Hg in North Atlantic marine food webs. To this end, we combined tracking data of 837 seabirds from seven different species and 27 breeding colonies located across the North Atlantic and Atlantic Arctic together with Hg analyses in feathers representing individual seabird contamination based on their winter distribution. Our results highlight an east-west gradient in Hg concentrations with hot spots around southern Greenland and the east coast of Canada and a cold spot in the Barents and Kara Seas. We hypothesize that those gradients are influenced by eastern (Norwegian Atlantic Current and West Spitsbergen Current) and western (East Greenland Current) oceanic currents and melting of the Greenland Ice Sheet. By tracking spatial Hg contamination in marine ecosystems and through the identification of areas at risk of Hg toxicity, this study provides essential knowledge for international decisions about where the regulation of pollutants should be prioritized.

Individual quality overwrites carry-over effects across the annual cycle of a long-distance migrant.

In seasonal environments, the fitness of animals depends upon the successful integration of life-history stages throughout their annual cycle. Failing to do so can lead to negative carry-over effects where individuals are transitioning into the next season in different states, consequently affecting their future performance. However, carry-over effects can be masked by individual quality when individuals vary in their efficiency at acquiring resources year after year (i.e. 'quality'), leading to cross-seasonal consistency in individual performance. Here we investigated the relative importance of carry-over effects and individual quality in determining cross-seasonal interactions and consequences for breeding success over the full annual cycle of a migratory seabird (black-legged kittiwake Rissa tridactyla). We monitored the reproduction and annual movement of kittiwakes over 13 years using geolocators to estimate their breeding success, distribution and winter energy expenditure. We combined this with an experimental approach (clutch removal experiment, 2 years) to manipulate the reproductive effort irrespective of individual quality. Piecewise path analyses showed that successful breeders reproduced earlier and were more likely to breed successfully again the following year. This positive interaction among consecutive breeding stages disappeared after controlling for individual quality, suggesting that quality was dominant in determining seasonal interactions. Moreover, controlling experimentally for individual quality revealed underlying carry-over effects that were otherwise masked by quality, with breeding costs paid in higher energy expenditure and delayed onset of reproduction. We highlight the need to combine an experimental approach along with long-term data while assessing apparent carry-over effects in wild animals, and their potential impact on fitness and population demography.

Winter Tracking Data Suggest that Migratory Seabirds Transport Per- and Polyfluoroalkyl Substances to Their Arctic Nesting Site.

Seabirds are often considered sentinel species of marine ecosystems, and their blood and eggs utilized to monitor local environmental contaminations. Most seabirds breeding in the Arctic are migratory and thus are exposed to geographically distinct sources of contamination throughout the year, including per- and polyfluoroalkyl substances (PFAS). Despite the abundance and high toxicity of PFAS, little is known about whether blood concentrations at breeding sites reliably reflect local contamination or exposure in distant wintering areas. We tested this by combining movement tracking data and PFAS analysis (nine compounds) from the blood of prelaying black-legged kittiwakes (Rissa tridactyla) nesting in Arctic Norway (Svalbard). PFAS burden before egg laying varied with the latitude of the wintering area and was negatively associated with time upon return of individuals at the Arctic nesting site. Kittiwakes (n = 64) wintering farther south carried lighter burdens of shorter-chain perfluoroalkyl carboxylates (PFCAs, C9-C12) and heavier burdens of longer chain PFCAs (C13-C14) and perfluorooctanesulfonic acid compared to those wintering farther north. Thus, blood concentrations prior to egg laying still reflected the uptake during the previous wintering stage, suggesting that migratory seabirds can act as biovectors of PFAS to Arctic nesting sites.

Meeting Paris agreement objectives will temper seabird winter distribution shifts in the North Atlantic Ocean.

We explored the implications of reaching the Paris Agreement Objective of limiting global warming to <2°C for the future winter distribution of the North Atlantic seabird community. We predicted and quantified current and future winter habitats of five North Atlantic Ocean seabird species (Alle alle, Fratercula arctica, Uria aalge, Uria lomvia and Rissa tridactyla) using tracking data for ~1500 individuals through resource selection functions based on mechanistic modeling of seabird energy requirements, and a dynamic bioclimate envelope model of seabird prey. Future winter distributions were predicted to shift with climate change, especially when global warming exceed 2°C under a "no mitigation" scenario, modifying seabird wintering hotspots in the North Atlantic Ocean. Our findings suggest that meeting Paris agreement objectives will limit changes in seabird selected habitat location and size in the North Atlantic Ocean during the 21st century. We thereby provide key information for the design of adaptive marine-protected areas in a changing ocean.

Scale-dependent response diversity of seabirds to prey in the North Sea.

Functional response diversity is defined as the diversity of responses to environmental change among species that contribute to the same ecosystem function. Because different ecological processes dominate on different spatial and temporal scales, response diversity is likely to be scale dependent. Using three extensive data sets on seabirds, pelagic fish, and zooplankton, we investigate the strength and diversity in the response of seabirds to prey in the North Sea over three scales of ecological organization. Two-stage analyses were used to partition the variance in the abundance of predators and prey among the different scales of investigation: variation from year to year, variation among habitats, and variation on the local patch scale. On the year-to-year scale, we found a strong and synchronous response of seabirds to the abundance of prey, resulting in low response diversity. Conversely, as different seabird species were found in habitats dominated by different prey species, we found a high diversity in the response of seabirds to prey on the habitat scale. Finally, on the local patch scale, seabirds were organized in multispecies patches. These patches were weakly associated with patches of prey, resulting in a weak response strength and a low response diversity. We suggest that ecological similarities among seabird species resulted in low response diversity on the year-to-year scale. On the habitat scale, we suggest that high response diversity was due to interspecific competition and niche segregation among seabird species. On the local patch scale, we suggest that facilitation with respect to the detection and accessibility of prey patches resulted in overlapping distribution of seabirds but weak associations with prey. The observed scale dependencies in response strength and diversity have implications for how the seabird community will respond to different environmental disturbances.

One- and five-year follow-ups on blood pressure and renal function in kidney donors.

It is considered safe to donate a kidney if internationally accepted medical criteria are fulfilled. However, some donors have encountered hypertension, proteinuria and impaired renal function after donation. The study was based on retrospective data on 908 donors, donating in the period 1997-2007. Preoperative and follow-up data were collected from patient files and the Norwegian Living Donor Registry. Follow-up data were available for 665 donors at 1 year after donation, and 256 donors at 5 years after donation. We calculated the estimated glomerular filtration rate (eGFR) using the four variable Modification of Diet in Renal Disease equation. At 1 and 5 years after donation, the prevalence of hypertension was 11.7% and 27.1% respectively compared to 2.6% before donation. Proteinuria was present in 3.3% and 1.6% at 1 and 5 years. Mean eGFR was 56.1 ± 10.8 ml/min/1.73 m² at 1 year and 61.0 ± 11.8 ml/min/1.73 m² at 5 years. Mean blood pressure was 122.5 ± 10.6/76.2 ± 7.5 mmHg at donation (n = 908), 124.3 ± 14.2/77.9 ± 8.2 mmHg at 1-year (n = 649) and 127.2 ± 15.4/78.8 ± 8.3 mmHg at 5-year follow-ups (n = 247). We found no evidence of further decline in renal function beyond the initial decrement following nephrectomy.

Real-time predictions of seabird distribution improve oil spill risk assessments.

Current knowledge of the distribution of sensitive seabirds is inadequate to safeguard seabird populations from impacts of oil spills in the Arctic. This gap is mainly driven by the fact that statistical models applied to survey data are coarse-scale and static with limited documentation of the distributional dynamics and patchiness of seabirds relevant to risk assessments related to oil spills. This paper describes a dynamic modelling framework solution for prediction of fine-scale densities and movements of seabirds in close-to-real time using fully integrated 3-D hydrodynamic models, dynamic habitat suitability models and agent-based models. The modelling framework has been developed and validated for the swimming migration of Brünnich's Guillemot Uria lomvia in the Barents Sea. The results document that the distributional dynamics of Brünnich's Guillemot and other seabird species to a large degree can be simulated with in-situ state variables and patterns reflecting the physical meteorology and oceanography and habitat suitability.

Blue justice: A survey for eliciting perceptions of environmental justice among coastal planners' and small-scale fishers in Northern-Norway.

Ocean-based economic development arising from an increasing interest in the 'blue economy' is placing ecosystems and small-scale fisheries under pressure. The dominant policy response for dealing with multiple uses is the allocation of coastal space through coastal zone planning (CZP). Recent studies have shown that the rush to develop the blue economy and regulate coastal activity can result in social injustices and the exclusion of less powerful and unrecognized groups (e.g., small-scale fishers, women, Indigenous peoples and youth). To achieve a primary goal of the 2030 sustainable development agenda to "leave no one behind", it is important to understand the implications of coastal planning and development for these groups. Here, we present a social survey protocol for examining perceptions of justice related to small-scale fisheries (SSF) in the context of the blue economy in coastal areas. Specifically, we designed the survey instrument and sampling protocol to assess whether decisions about the use of the coastal zone over the last five years have i) followed principles of good governance, ii) recognized fishers' knowledge, culture and rights and iii) been attentive to impacts of changed coastal zone use on fisheries. The survey will engage coastal planners (N = app. 120) and fishers (N = app. 4300) in all the coastal municipalities (N = 81) in Northern-Norway. The sampling protocol is designed to ensure representation of different sectors of society, including those defined by gender, age, ethnicity and occupation (e.g., small-scale fishers, large-scale fishers, coastal planners).

North Atlantic winter cyclones starve seabirds.

Each winter, the North Atlantic Ocean is the stage for numerous cyclones, the most severe ones leading to seabird mass-mortality events called "winter wrecks."1-3 During these, thousands of emaciated seabird carcasses are washed ashore along European and North American coasts. Winter cyclones can therefore shape seabird population dynamics4,5 by affecting survival rates as well as the body condition of surviving individuals and thus their future reproduction. However, most often the geographic origins of impacted seabirds and the causes of their deaths remain unclear.6 We performed the first ocean-basin scale assessment of cyclone exposure in a seabird community by coupling winter tracking data for ∼1,500 individuals of five key North Atlantic seabird species (Alle alle, Fratercula arctica, Uria aalge, Uria lomvia, and Rissa tridactyla) and cyclone locations. We then explored the energetic consequences of different cyclonic conditions using a mechanistic bioenergetics model7 and tested the hypothesis that cyclones dramatically increase seabird energy requirements. We demonstrated that cyclones of high intensity impacted birds from all studied species and breeding colonies during winter but especially those aggregating in the Labrador Sea, the Davis Strait, the surroundings of Iceland, and the Barents Sea. Our broad-scale analyses suggested that cyclonic conditions do not increase seabird energy requirements, implying that they die because of the unavailability of their prey and/or their inability to feed during cyclones. Our study provides essential information on seabird cyclone exposure in a context of marked cyclone regime changes due to global warming.8.

Predator-prey reversal: a possible mechanism for ecosystem hysteresis in the North Sea?

Removal of large predatory fishes from marine ecosystems has resulted in persistent ecosystem shifts, with collapsed predator populations and super-abundant prey populations. One explanation for these shifts is reversals of predator-prey roles that generate internal feedbacks in the ecosystems. Pelagic forage fish are often predators and competitors to the young life stages of their larger fish predators. I show that cod recruitment in the North Sea has been negatively related to the spawning-stock biomass of herring for the last 44 years. Herring, together with the abundance of Calanus finmarchicus, the major food for cod larvae, were the main predictors of cod recruitment. These predictors were of equivalent importance, worked additively, and explained different parts of the dynamics in cod recruitment. I suggest that intensive harvesting of cod has released herring from predator control, and that a large population of herring suppresses cod recruitment through predation on eggs and larvae. This feedback mechanism can promote alternative stable states and therefore cause hysteresis to occur under changing conditions; however, harvesting of herring might at present prevent a shift in the ecosystem to a herring-dominated state.

Observational evidence of risk-sensitive reproductive allocation in a long-lived mammal.

Organisms should adopt a risk-sensitive reproductive allocation when summer reproductive allocation competes with survival in the coming winter. This trade off is shown through autumn female body mass, which acts as an insurance against unpredictable winter environmental conditions. We tested this hypothesis on female reindeer in a population that has experienced a time period of dramatic increase in abundance. Environmental conditions during winter were fairly stable (with the exception of 1 year). We conclude that increased population abundance (perhaps in interaction with winter environmental conditions) could have represented a worsening of winter environmental conditions as both autumn offspring and spring female body mass decreased during the course of the study. Moreover, we found that the cost of reproduction was related to environmental conditions as: (1) autumn body mass was larger for barren than for lactating females, and this difference was temporally highly variable; (2) lactating females produced smaller offspring than barren ones in the following year; and (3) reproductive output (offspring size) decreased over time. We also found evidence of quality effects as lactating females had a higher reproductive success in the following year. In sum, a worsening of winter conditions lead to: (1) decreased reproductive output; (2) lowered autumn body mass for lactating females; and (3) increased body mass for barren females. Since females reduce their reproductive allocation as winter conditions becomes more severe, we conclude that reindeer have adopted a risk-sensitive reproductive allocation.

Short- and long-term consequences of reproductive decisions: an experimental study in the puffin.

The purpose of the present study was to inspect the response of the Atlantic Puffin (Fratercula arctica) to an experimental manipulation of the investment needed to successfully raise an offspring. We achieved this by replacing an old offspring with a younger chick, and vice versa, thereby prolonging and shortening the chick-rearing period. To examine any costs of reproduction we then followed the breeding success, the recruitment of young to the population, and the survival of parents for 11 years following the manipulation. Parents in the prolonged and shortened category had a lower breeding success than controls mainly because parents deserted their chick shortly after swapping. Among those that raised their chick, the age and body mass of foster chicks at fledging were the same in all three categories even though the parents had raised chicks for different lengths of time. The recruitment of young to the breeding population was high and independent of treatment. Likewise, the survival of adults was independent of treatment. For the 11 years after the experiment, however, the resighting rate of those that deserted their chick was clearly lower than among those that accepted their foster chick. For parents that raised their foster chick, the survival to the following year was positively related to their body mass. The results support the hypothesis that puffins have a highly flexible parental investment, which they adjust according to their own individual quality and the survival prospects of the chick.

Stakeholders' perceptions of protected area management following a nationwide community-based conservation reform.

People's perceptions can point to reasons for conservation support or lack thereof. In this study, we surveyed the perceptions of conservation among local stakeholders who participated in protected area (PA) management following a reform towards community-based conservation in Norway. We analyzed the link between perceptions of threats to conservation values, prioritized management actions and trust in PA governance, and assessed how these perceptions aligned with the stakeholders' preferred overarching conservation approach and their support for PAs. Conservation perceptions differed mostly between property owners and representatives of nature conservation (such as NGOs). Property owners perceived modern farming, grazing and hay making, and securing the interests of rights holders as a priority. They had a lower support for PAs and favored a conservation approach focusing on "people and nature". Representatives from nature conservation prioritized management actions to increase biodiversity and reduce land development, had higher trust in environmental authorities and identified motorized vehicle use as a threat to conservation values. They had a high support for PAs and favored a conservation approach that mitigates threats from human activity (i.e. "nature despite people"). The nationwide reform aimed at increasing support for PAs, but 31% of the members of the stakeholder advisory councils were willing to downgrade or degazette PAs for the benefit of economic development, which is much more than general population surveys. However, the level of trust in local governance was less polarized among the members of stakeholder advisory councils compared with the former state governance, which suggests that that the community-based conservation reform has the potential to improve collaboration and conflict mitigation.

Local land use associated with socio-economic development in six arctic regions.

The socioeconomic causes of land use change are complex. They are highly context dependent, but most often studied through case studies. Here, we use a quasi-experimental paired block design to investigate whether better access to wage income leads to more visible land use around 28 settlements in six regions of the circumpolar Arctic. We mapped visible land use on high-resolution satellite images taken both close to the settlements, and in a more remote area of extensive land use, and payed special attention to tracks of off-road vehicles (ORV). Despite considerable differences among regions, there was an overall positive relationship between better access to wage income and land use. Reindeer herding was also associated with more visible use, in particular ORV tracks. These results suggest that access to wage income in the mixed subsistence-cash communities of the Arctic could lead to more local use related to harvesting and reindeer herding.

Experimental evidence of a risk-sensitive reproductive allocation in a long-lived mammal.

When reproduction competes with the amount of resources available for survival during an unpredictable nonbreeding season, individuals should adopt a risk-sensitive regulation of their reproductive allocation. We tested this hypothesis on female reindeer (Rangifer tarandus), which face a trade-off between reproduction and acquisition of body reserves during spring and summer, with autumn body mass functioning as insurance against stochastic winter climatic severity. The study was conducted in a population consisting of two herds: one that received supplementary winter feeding for four years while the other utilized natural pastures. The females receiving additional forage allocated more to their calves. Experimental translocation of females between the herds was conducted to simulate two contrasting rapid alterations of winter conditions. When females receiving supplementary feeding were moved to natural pastures, they promptly reduced their reproductive allocation the following summer. However, when winter conditions were improved, females were reluctant to increase their reproductive allocation. This asymmetric response to improved vs. reduced winter conditions is consistent with a risk-averse adjustment in reproductive allocation. The ability of individuals to track their environment and the concordant risk-sensitive adjustment of reproductive allocation may render subarctic reindeer more resilient to climate change than previously supposed.

Arctic greening from warming promotes declines in caribou populations.

The migratory tundra caribou herds in North America follow decadal population cycles, and browsing from abundant caribou could be expected to counteract the current climate-driven expansion of shrubs in the circumpolar tundra biome. We demonstrate that the sea ice cover in the Arctic Ocean has provided a strong signal for climate-induced changes on the adjacent caribou summer ranges, outperforming other climate indices in explaining the caribou-plant dynamics. We found no evidence of a negative effect of caribou abundance on vegetation biomass. On the contrary, we found a strong bottom-up effect in which a warmer climate related to diminishing sea ice has increased the plant biomass on the summer pastures, along with a paradoxical decline in caribou populations. This result suggests that this climate-induced greening has been accompanied by a deterioration of pasture quality. The shrub expansion in Arctic North America involves plant species with strong antibrowsing defenses. Our results might therefore be an early signal of a climate-driven shift in the caribou-plant interaction from a system with low plant biomass modulated by cyclic caribou populations to a system dominated by nonedible shrubs and diminishing herds of migratory caribou.

Calcineurin inhibitor avoidance with daclizumab, mycophenolate mofetil, and prednisolone in DR-matched de novo kidney transplant recipients.

BACKGROUND: Calcineurin inhibitor (CNI)-free regimens posttransplantation have been claimed to conserve graft function in addition to reduce the risk factors for cardiovascular and malignant disease in renal transplant recipients. METHODS: The primary aim of this prospective, open-label, randomized, parallel-group, single-center study was to compare the effect of complete CNI-avoidance posttransplant (daclizumab + mycophenolate mofetil + prednisolone: Dac-group, n=27) with the standard CNI-based immunosuppressive protocol at our transplant unit (cyclosporine A + mycophenolate mofetil + prednisolone: CsA-group, n=27) on renal function (glomerular filtration rate [GFR] determined as plasma clearance of 51Cr-EDTA) in a selected low immunogenic risk population (DR-matched, PRA-negative de novo cadaveric transplant recipients). RESULTS: There were no significant difference in GFR at week 10 (P=0.61), but GFR was significantly (P=0.029) lower in the Dac-group (52+/-20 ml/min) at month 12 than in the CsA-group (69+/-29 ml/min). One-year patient and graft survival did not differ between the two groups. Overall acute rejection rate was 70.4% (19/27) in the Dac-group and 29.6% (8/27) in the CsA-group (P=0.006). CONCLUSIONS: The strategy to select DR-matched, PRA-negative de novo cadaveric transplant recipients for a CNI-avoidance protocol was not successful. The incidence of acute rejection was unacceptable high even though anti-CD25 antibody induction as well as initial higher mycophenolate mofetil doses (3 g/day) were applied, and renal function was significantly lower in the CNI-avoidance patients at 1 year. Other strategies need to be examined for avoidance of CNI's in the early posttransplant period.

Density-dependent migratory waves in the marine pelagic ecosystem.

The migration of large aggregations of animals that sweep through the landscape is a phenomenon with large consequences in many ecosystems. It has been suggested that such migrations are mediated by resource depletion. Under this hypothesis it has been shown that simple foraging rules may generate density-dependent migratory waves (DDMW) in which the speed and amplitude increase with animal abundance. We tested these predictions on a 32-year data set of the spatial distribution of the two youngest age groups of a small pelagic schooling fish, the capelin (Mallotus villosus), by the end of their annual feeding migration in the Barents Sea. Our data suggest that the two age groups divided the Barents Sea by forming migratory waves that moved in opposite directions. The aggregation and spatial displacement of these waves increased with increasing age-specific abundance. However, possibly through social interactions, migratory pattern was modified by the abundance of the other age group.

Effect of fluvastatin on cardiac outcomes in renal transplant recipients: a multicentre, randomised, placebo-controlled trial.

BACKGROUND: Renal transplant recipients are at increased risk of premature cardiovascular disease. Although statins reduce cardiovascular risk in the general population, their efficacy and safety in renal transplant recipients have not been established. We investigated the effects of fluvastatin on cardiac and renal endpoints in this population. METHODS: We did a multicentre, randomised, double-blind, placebo-controlled trial in 2102 renal transplant recipients with total cholesterol 4.0-9.0 mmol/L. We randomly assigned patients fluvastatin (n=1050) or placebo (n=1052) and follow up was for 5-6 years. The primary endpoint was the occurrence of a major adverse cardiac event, defined as cardiac death, non-fatal myocardial infarction (MI), or coronary intervention procedure. Secondary endpoints were individual cardiac events, combined cardiac death or non-fatal MI, cerebrovascular events, non-cardiovascular death, all-cause mortality, and graft loss or doubling of serum creatinine. Analysis was by intention to treat. FINDINGS: After a mean follow-up of 5.1 years, fluvastatin lowered LDL cholesterol concentrations by 32%. Risk reduction with fluvastatin for the primary endpoint (risk ratio 0.83 [95% CI 0.64-1.06], p=0.139) was not significant, although there were fewer cardiac deaths or non-fatal MI (70 vs 104, 0.65 [0.48-0.88] p=0.005) in the fluvastatin group than in the placebo group. Coronary intervention procedures and other secondary endpoints did not differ significantly between groups. INTERPRETATION: Although cardiac deaths and non-fatal MI seemed to be reduced, fluvastatin did not generally reduce rates of coronary intervention procedures or mortality. Overall effects of fluvastatin were similar to those of statins in other populations.