Local-scale impacts of extreme events drive demographic asynchrony in neighbouring top predator populations.

Extreme weather events are among the most critical aspects of climate change, but our understanding of their impacts on biological populations remains limited. Here, we exploit the rare opportunity provided by the availability of concurrent longitudinal demographic data on two neighbouring marine top predator populations (the black-browed albatross, Thalassarche melanophris, breeding in two nearby colonies) hit by an exceptionally violent storm during one study year. The aim of this study is to quantify the demographic impacts of extreme events on albatrosses and test the hypothesis that extreme events would synchronously decrease survival rates of neighbouring populations. Using demographic modelling we found that, contrary to our expectation, the storm affected the survival of albatrosses from only one of the two colonies, more than doubling the annual mortality rate compared to the study average. Furthermore, the effects of storms on adult survival would lead to substantial population declines (up to 2% per year) under simulated scenarios of increased storm frequencies. We, therefore, conclude that extreme events can result in very different local-scale impacts on sympatric populations. Crucially, by driving demographic asynchrony, extreme events can hamper our understanding of the demographic responses of wild populations to mean, long-term shifts in climate.

Potential for redistribution of post-moult habitat for Eudyptes penguins in the Southern Ocean under future climate conditions.

Anthropogenic climate change is resulting in spatial redistributions of many species. We assessed the potential effects of climate change on an abundant and widely distributed group of diving birds, Eudyptes penguins, which are the main avian consumers in the Southern Ocean in terms of biomass consumption. Despite their abundance, several of these species have undergone population declines over the past century, potentially due to changing oceanography and prey availability over the important winter months. We used light-based geolocation tracking data for 485 individuals deployed between 2006 and 2020 across 10 of the major breeding locations for five taxa of Eudyptes penguins. We used boosted regression tree modelling to quantify post-moult habitat preference for southern rockhopper (E. chrysocome), eastern rockhopper (E. filholi), northern rockhopper (E. moseleyi) and macaroni/royal (E. chrysolophus and E. schlegeli) penguins. We then modelled their redistribution under two climate change scenarios, representative concentration pathways RCP4.5 and RCP8.5 (for the end of the century, 2071-2100). As climate forcings differ regionally, we quantified redistribution in the Atlantic, Central Indian, East Indian, West Pacific and East Pacific regions. We found sea surface temperature and sea surface height to be the most important predictors of current habitat for these penguins; physical features that are changing rapidly in the Southern Ocean. Our results indicated that the less severe RCP4.5 would lead to less habitat loss than the more severe RCP8.5. The five taxa of penguin may experience a general poleward redistribution of their preferred habitat, but with contrasting effects in the (i) change in total area of preferred habitat under climate change (ii) according to geographic region and (iii) the species (macaroni/royal vs. rockhopper populations). Our results provide further understanding on the regional impacts and vulnerability of species to climate change.

In-situ bypass is associated with superior infection-free survival compared with extra-anatomic bypass for the management of secondary aortic graft infections without enteric involvement.

OBJECTIVE: The optimal revascularization modality following complete resection of aortic graft infection (AGI) without enteric involvement remains unclear. The purpose of this investigation is to determine the revascularization approach associated with the lowest morbidity and mortality using real-world data in patients undergoing complete excision of AGI. METHODS: A retrospective, multi-institutional study of AGI from 2002 to 2014 was performed using a standardized database. Baseline demographics, comorbidities, and perioperative variables were recorded. The primary outcome was infection-free survival. Descriptive statistics, Kaplan-Meier survival analysis, and univariate and multivariable analyses were performed. RESULTS: A total of 241 patients at 34 institutions from seven countries presented with AGI during the study period (median age, 68 years; 75% male). The initial aortic procedures that resulted in AGI were 172 surgical grafts (71%), 66 endografts (27%), and three unknown (2%). Of the patients, 172 (71%) underwent complete excision of infected aortic graft material followed by in situ (in-line) bypass (ISB), including antibiotic-treated prosthetic graft (35%), autogenous femoral vein (neo-aortoiliac surgery) (24%), and cryopreserved allograft (41%). Sixty-nine patients (29%) underwent extra-anatomic bypass (EAB). Overall median Kaplan-Meier estimated survival was 5.8 years. Perioperative mortality was 16%. When stratified by ISB vs EAB, there was a significant difference in Kaplan-Meier estimated infection-free survival (2910 days; interquartile range, 391-3771 days vs 180 days; interquartile range, 27-3750 days; P < .001). There were otherwise no significant differences in presentation, comorbidities, or perioperative variables. Multivariable Cox regression showed lower infection-free survival among patients with EAB (hazard ratio [HR], 2.4; 95% confidence interval [CI], 1.6-3.6; P < .001), polymicrobial infection (HR, 2.2; 95% CI, 1.4-3.5; P = .001), methicillin-resistant Staphylococcus aureus infection (HR, 1.7; 95% CI, 1.1-2.7; P = .02), as well as the protective effect of omental/muscle flap coverage (HR, 0.59; 95% CI, 0.37-0.92; P = .02). CONCLUSIONS: After complete resection of AGI, perioperative mortality is 16% and median overall survival is 5.8 years. EAB is associated with nearly a two and one-half-fold higher reinfection/mortality compared with ISB. Omental and/or muscle flap coverage of the repair appear protective.

A call for standardised age-disaggregated health data.

The 2030 Sustainable Development Goals agenda calls for health data to be disaggregated by age. However, age groupings used to record and report health data vary greatly, hindering the harmonisation, comparability, and usefulness of these data, within and across countries. This variability has become especially evident during the COVID-19 pandemic, when there was an urgent need for rapid cross-country analyses of epidemiological patterns by age to direct public health action, but such analyses were limited by the lack of standard age categories. In this Personal View, we propose a recommended set of age groupings to address this issue. These groupings are informed by age-specific patterns of morbidity, mortality, and health risks, and by opportunities for prevention and disease intervention. We recommend age groupings of 5 years for all health data, except for those younger than 5 years, during which time there are rapid biological and physiological changes that justify a finer disaggregation. Although the focus of this Personal View is on the standardisation of the analysis and display of age groups, we also outline the challenges faced in collecting data on exact age, especially for health facilities and surveillance data. The proposed age disaggregation should facilitate targeted, age-specific policies and actions for health care and disease management.

Comparison of 30 Day Stroke and Death in Hybrid Intervention and Open Surgical Reconstruction for the Treatment of Tandem Carotid Bifurcation and Supra-aortic Trunk Disease.

OBJECTIVE: The optimal approach for the treatment of tandem carotid bifurcation and supra-aortic trunk (SAT) disease remains controversial. The hybrid technique of carotid endarterectomy (CEA) with ipsilateral proximal endovascular intervention (IPE) has provided an attractive alternative to CEA with open SAT reconstruction (SATr). However, no studies have compared cohorts treated by these two approaches. METHODS: Using the National Surgical Quality Improvement Program (2005-2017), patients who underwent CEA + IPE and CEA + SATr were identified. Non-occlusive indications were excluded. Primary outcomes included 30 day stroke, death, and their composite (stroke and/or death [SD]). Univariable and logistic regression analyses were performed. RESULTS: In total, 372 patients were identified: 319 CEA + SATr and 53 CEA + IPE. SATr included 19 (5.9%) aorta to carotid bypasses, 22 (6.9%) carotid subclavian transpositions, 96 (30.1%) carotid carotid bypasses, 179 (56.1%) carotid subclavian bypasses, and three (0.9%) SAT endarterectomies. The mean age was 69 ± 10 years. The majority were men (53%), white (85%), and had a history of hypertension (84%). There were no demographic differences between the operative cohorts except that those having CEA + SATr were more likely to have hypertension (86% vs. 74%; p = .031). CEA + SATr had longer operative times and longer hospital length of stay. There were no differences in outcomes between the cohorts: stroke (CEA + SATr 4.1% vs. CEA + IPE 3.8%; p = .92), death (1.6% vs. 0%; p = .36), or SD (5.3% vs. 3.8%; p = .63). After risk adjustment, predictors of SD included symptomatic status (odds ratio [OR] 3.9, 95% confidence interval [CI] 1.1-13.5; p = .034), congestive heart failure (OR 16.5, 95% CI 2.0-136; p = .011), and return to the operating room (OR 8.5, 95% CI 2.3-30.8; p = .001). Operative method was not predictive (p = .63). CONCLUSION: Outcomes following CEA + SATr and CEA + IPE are similar. Although proposed as a safer, less invasive alternative, the hybrid approach did not reduce the risk of operative stroke or death relative to open reconstruction for the treatment of occlusive, tandem carotid/SAT disease. Based upon lesion and patient factors, both may be considered management options in select patients.

Impact of Adding Carotid Endarterectomy to Supra-aortic Trunk Surgical Reconstruction.

BACKGROUND: Up to 20% of patients requiring open supra-aortic trunk (SAT) reconstruction have significant carotid artery stenosis. The addition of carotid endarterectomy (CEA) to SAT has been described. Yet, additive risks are not well defined and controversy remains as to whether concomitant CEA increases stroke risk. This study assessed the perioperative effects of adding CEA to SAT. METHODS: Using the National Surgical Quality Improvement Program (NSQIP), patients who underwent SAT from 2005 to 2015 were evaluated. SAT + CEA were identified. An isolated SAT (ISAT) cohort was created by removing patients who underwent concurrent secondary procedures. Nonocclusive indications were excluded. SAT + CEA were compared with ISAT as well as a propensity-matched ISAT cohort. Primary outcomes were 30-day stroke, death, and composite stroke/death/myocardial infarction (SDM). Univariate and logistic regression analyses were performed. RESULTS: After review, 1,515 patients were identified: 1,245 ISAT (82%) and 270 SAT + CEA (18%). Most were women (56%), 86% were Caucasian, and 24% were symptomatic. Average age was 65 ± 12 years and SAT + CEA were older (69 vs. 64 years, P < 0.001). CEA + SAT were more likely to be men (53% vs. 42%, P < 0.001), have hypertension (86% vs. 75%, P < 0.001) and diabetes (26% vs. 20%, P = 0.04). SAT procedures included the following: carotid-subclavian bypass (68%), carotid-carotid bypass (16%), aorta-great vessel bypass (9%), and carotid-subclavian transposition (7%). ISAT were more likely to undergo carotid-subclavian bypass than SAT + CEA (71% vs. 54%, P < 0.001). Overall stroke was 2.3%, death 1.4%, and SDM 4.6%. There were no differences in 30-day stroke (ISAT 2.0% vs. SAT + CEA 3.7%, P = 0.09) or mortality (1.4% vs. 1.5%, P = 0.88). SAT + CEA had higher rates of SDM (7% vs. 4%, P = 0.03). On logistic regression, urgency was a predictor of SDM (operating room [OR] 3.6, 95% confidence interval [CI] 1.5-8.4, P = 0.003); addition of CEA was not predictive of stroke (OR 1.4, 95% CI 0.5-4.2, P = 0.52) or SDM (OR 1.5, 95% CI 0.6-3.6, P = 0.40). After propensity matching, there were no longer differences in demographics or primary end points between the 2 cohorts. CONCLUSIONS: Addition of CEA does not confer increased perioperative stroke or SDM risk over ISAT. Perioperative outcomes appear to be more affected by disseminated disease risk factors than the addition of CEA. In patients undergoing SAT, it is reasonable to consider performing combined CEA in populations with tandem carotid bifurcation disease and appropriate operative risk profile.

Evidence of Pathogen-Induced Immunogenetic Selection across the Large Geographic Range of a Wild Seabird.

Over evolutionary time, pathogen challenge shapes the immune phenotype of the host to better respond to an incipient threat. The extent and direction of this selection pressure depend on the local pathogen composition, which is in turn determined by biotic and abiotic features of the environment. However, little is known about adaptation to local pathogen threats in wild animals. The Gentoo penguin (Pygoscelis papua) is a species complex that lends itself to the study of immune adaptation because of its circumpolar distribution over a large latitudinal range, with little or no admixture between different clades. In this study, we examine the diversity in a key family of innate immune genes-the Toll-like receptors (TLRs)-across the range of the Gentoo penguin. The three TLRs that we investigated present varying levels of diversity, with TLR4 and TLR5 greatly exceeding the diversity of TLR7. We present evidence of positive selection in TLR4 and TLR5, which points to pathogen-driven adaptation to the local pathogen milieu. Finally, we demonstrate that two positively selected cosegregating sites in TLR5 are sufficient to alter the responsiveness of the receptor to its bacterial ligand, flagellin. Taken together, these results suggest that Gentoo penguins have experienced distinct pathogen-driven selection pressures in different environments, which may be important given the role of the Gentoo penguin as a sentinel species in some of the world's most rapidly changing environments.

Author Correction: Important At-Sea Areas of Colonial Breeding Marine Predators on the Southern Patagonian Shelf.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Phylogeography, Population Structure, and Species Delimitation in Rockhopper Penguins (Eudyptes chrysocome and Eudyptes moseleyi).

Rockhopper penguins are delimited as 2 species, the northern rockhopper (Eudyptes moseleyi) and the southern rockhopper (Eudyptes chrysocome), with the latter comprising 2 subspecies, the western rockhopper (Eudyptes chrysocome chrysocome) and the eastern rockhopper (Eudyptes chrysocome filholi). We conducted a phylogeographic study using multilocus data from 114 individuals sampled across 12 colonies from the entire range of the northern/southern rockhopper complex to assess potential population structure, gene flow, and species limits. Bayesian and likelihood methods with nuclear and mitochondrial DNA, including model testing and heuristic approaches, support E. moseleyi and E. chrysocome as distinct species lineages with a divergence time of 0.97 Ma. However, these analyses also indicated the presence of gene flow between these species. Among southern rockhopper subspecies, we found evidence of significant gene flow and heuristic approaches to species delimitation based on the genealogical diversity index failed to delimit them as species. The best-supported population models for the southern rockhoppers were those where E. c. chrysocome and E. c. filholi were combined into a single lineage or 2 lineages with bidirectional gene flow. Additionally, we found that E. c. filholi has the highest effective population size while E. c. chrysocome showed similar effective population size to that of the endangered E. moseleyi. We suggest that the current taxonomic definitions within rockhopper penguins be upheld and that E. chrysocome populations, all found south of the subtropical front, should be treated as a single taxon with distinct management units for E. c. chrysocome and E. c. filholi.

Important At-Sea Areas of Colonial Breeding Marine Predators on the Southern Patagonian Shelf.

The Patagonian Shelf Large Marine Ecosystem supports high levels of biodiversity and endemism and is one of the most productive marine ecosystems in the world. Despite the important role marine predators play in structuring the ecosystems, areas of high diversity where multiple predators congregate remains poorly known on the Patagonian Shelf. Here, we used biotelemetry and biologging tags to track the movements of six seabird species and three pinniped species breeding at the Falkland Islands. Using Generalized Additive Models, we then modelled these animals' use of space as functions of dynamic and static environmental indices that described their habitat. Based on these models, we mapped the predicted distribution of animals from both sampled and unsampled colonies and thereby identified areas where multiple species were likely to overlap at sea. Maximum foraging trip distance ranged from 79 to 1,325 km. However, most of the 1,891 foraging trips by 686 animals were restricted to the Patagonian Shelf and shelf slope, which highlighted a preference for these habitats. Of the seven candidate explanatory covariates used to predict distribution, distance from the colony was retained in models for all species and negatively affected the probability of occurrence. Predicted overlap among species was highest on the Patagonian Shelf around the Falkland Islands and the Burdwood Bank. The predicted area of overlap is consistent with areas that are also important habitat for marine predators migrating from distant breeding locations. Our findings provide comprehensive multi-species predictions for some of the largest marine predator populations on the Patagonian Shelf, which will contribute to future marine spatial planning initiatives. Crucially, our findings highlight that spatially explicit conservation measures are likely to benefit multiple species, while threats are likely to impact multiple species.

Comparative population genomics reveals key barriers to dispersal in Southern Ocean penguins.

The mechanisms that determine patterns of species dispersal are important factors in the production and maintenance of biodiversity. Understanding these mechanisms helps to forecast the responses of species to environmental change. Here, we used a comparative framework and genomewide data obtained through RAD-Seq to compare the patterns of connectivity among breeding colonies for five penguin species with shared ancestry, overlapping distributions and differing ecological niches, allowing an examination of the intrinsic and extrinsic barriers governing dispersal patterns. Our findings show that at-sea range and oceanography underlie patterns of dispersal in these penguins. The pelagic niche of emperor (Aptenodytes forsteri), king (A. patagonicus), Adélie (Pygoscelis adeliae) and chinstrap (P. antarctica) penguins facilitates gene flow over thousands of kilometres. In contrast, the coastal niche of gentoo penguins (P. papua) limits dispersal, resulting in population divergences. Oceanographic fronts also act as dispersal barriers to some extent. We recommend that forecasts of extinction risk incorporate dispersal and that management units are defined by at-sea range and oceanography in species lacking genetic data.

Love thy neighbour or opposites attract? Patterns of spatial segregation and association among crested penguin populations during winter.

AIM: Competition for food among populations of closely related species and conspecifics that occur in both sympatry and parapatry can be reduced by interspecific and intraspecific spatial segregation. According to predictions of niche partitioning, segregation is expected to occur at habitat boundaries among congeners and within habitats among conspecifics, while negative relationships in the density of species or populations will occur in areas of overlap. We tested these predictions by modelling the winter distributions of two crested penguin species from three colonies in the south-western Atlantic. LOCATION: Penguins were tracked from two large colonies on the Falkland Islands and one in South Georgia, from where they dispersed through the South Atlantic, Southern Ocean and south-eastern Pacific. METHODS: Forty macaroni penguins (Eudyptes chrysolophus) from South Georgia and 82 southern rockhopper penguins (Eudyptes chrysocome chrysocome) from two colonies in the Falkland Islands were equipped with global location sensors which log time and light, allowing positions to be estimated twice-daily, from April to August in 2011. Positions were gridded and converted into maps of penguin density. Metrics of overlap were calculated and density was related to remote-sensed oceanographic variables and competitor density using generalized additive models. RESULTS: Macaroni penguins from western South Georgia and southern rockhopper penguins from Steeple Jason Island, Falkland Islands, were spatially segregated by differences in their habitat preferences thus supporting our first prediction regarding interspecific segregation. However, southern rockhopper penguins from Beauchêne Island showed a marked spatial overlap with macaroni penguins as the two had similar habitat preferences and strong mutual associations when controlling for habitat. Contrary to our predictions relating to intraspecific segregation, southern rockhopper penguins from Beauchêne Island and Steeple Jason Island were segregated by differences in habitat selection. MAIN CONCLUSIONS: Morphological differentiation probably allows macaroni penguins from South Georgia and southern rockhopper penguins from Beauchêne Island to coexist in areas of spatial overlap, whereas segregation of the two Falkland rockhopper penguin populations may have arisen from two distinct lineages retaining cultural fidelity to ancestral wintering areas.