Tycho Anker-Nilssen

Tycho Anker-Nilssen
Norwegian Institute for Nature Research | NINA · Department of Terrestrial Ecology

PhD

About

190
Publications
52,884
Reads
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6,445
Citations
Additional affiliations
September 1985 - present
Norwegian Institute for Nature Research
Position
  • Senior Researcher

Publications

Publications (190)
Article
Full-text available
Forage fish populations often undergo large and rapid fluctuations in abundance. However, most of their predators are buffered against such fluctuations owing to their slower pace of life, which allows them to maintain more stable populations, at least during short periods of food scarcity. In this study, we investigated top‐down processes exerted...
Article
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The current warming of the oceans has been shown to have detrimental effects for a number of species. An understanding of the underlying mechanisms may be hampered by the non-linearity and non-stationarity of the relationships between temperature and demography, and by the insufficient length of available time series. Most demographic time series a...
Article
Sampling seabirds The vastness of the worlds' oceans makes them difficult to monitor. Seabirds that forage and breed across oceans globally have been recognized as sentinels of ocean health. Sydeman et al. looked across seabird species of both the Northern and Southern Hemispheres and found varying patterns. Northern Hemisphere species exhibited gr...
Article
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Bottom‐up control is an important regulator of marine mesopredators such as seabirds. The prevalence of top‐down control on these species is however less well understood. In particular, how native predators affect seabird populations has rarely been quantified. Here, we investigate how an increase in white‐tailed eagles in northern Norway, a strong...
Article
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Actuarial senescence, the decline of survival with age, is well documented in the wild. Rates of senescence vary widely between taxa, to some extent also between sexes, with the fastest life histories showing the highest rates of senescence. Few studies have investigated differences in senescence among populations of the same species, although such...
Article
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Male and female birds have different roles in reproduction and, thereby in their reproductive investment, which in turn may increase negative effects of poorer breeding conditions caused by e.g., climate change or ecosystem regime shifts. By using a 33‐year time series of resightings of Atlantic puffins Fratercula arctica individually colour‐ringed...
Article
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In a warming Arctic, circumpolar long-term monitoring programs are key to advancing ecological knowledge and informing environmental policies. Calls for better involvement of Arctic peoples in all stages of the monitoring process are widespread, although such transformation of Arctic science is still in its infancy. Seabirds stand out as ecological...
Article
In a warming Arctic, circumpolar long-term monitoring programs are key to advancing ecological knowledge and informing environmental policies. Calls for better involvement of Arctic peoples in all stages of the monitoring process are widespread, although such transformation of Arctic science is still in its infancy. Seabirds stand out as ecological...
Article
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...
Article
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Polar ecosystems are subjected to many stressors, including climate change, that impact their overall functioning. Seabirds are good bioindicators of these systems as they readily respond to changes in environmental conditions. To quantify how environmental changes affect their life history, data on seabird diet, spatial distribution and body condi...
Article
Vertebrate populations are often monitored as part of broader assessments of ecosystem status, where they are expected to provide information on the ability of the ecosystem to support higher‐level predators. However, because many vertebrates are long‐lived and often only subsets of their populations can be monitored, abundance may not be sufficien...
Article
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Migration is a common trait among many animals allowing the exploitation of spatiotemporally variable resources. It often implies high energetic costs to cover large distances, for example between breeding and wintering grounds. For flying or swimming animals, the adequate use of winds and currents can help reduce the associated energetic costs. Mi...
Article
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The Arctic is experiencing the fastest rates of global warming, leading to shifts in the distribution of its biota and increasing the potential for hybridization. However, genomic evidence of recent hybridization events in the Arctic remains unexpectedly rare. Here, we use whole-genome sequencing of contemporary and 122-year-old historical specimen...
Article
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Demographic correlations are pervasive in wildlife populations and can represent important secondary drivers of population growth. Empirical evidence suggests that correlations are in general positive for long-lived species, but little is known about the degree of variation among spatially segregated populations of the same species in relation to e...
Article
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Conservation guidance—an authoritative source of information and recommendations explicitly supporting decision-making and action regarding nature conservation—represents an important tool to communicate evidence-based advice to conservation actors. Given the rapidly increasing pressure that climate change poses to biodiversity, producing accessibl...
Article
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The intensification of coastal development poses potential threats for coastal seabirds, and understanding their habitat use is a key factor to guide conservation and management. In sub-arctic areas, black guillemots (Cepphus grylle) use coastal habitats year-round, which makes them vulnerable to the increasing human activities in these areas. In m...
Preprint
Full-text available
Demographic correlations are pervasive in wildlife populations and can represent important secondary drivers of population growth. Empirical evidence suggests that correlations are in general positive for long-lived species, however little is known about the degree of variation among populations in relation to local conditions. For three widely geo...
Preprint
Demographic correlations are pervasive in wildlife populations and can represent important secondary drivers of population growth. Empirical evidence suggests that correlations are in general positive for long-lived species, however little is known about the degree of variation among populations in relation to local conditions. For three widely geo...
Article
Full-text available
Across its range, the Atlantic Puffin (Fratercula arctica) is divided into four separate genetic clusters that correspond with geography and/or size differences. However, in the Western Atlantic High Arctic, there is a Puffin colony (“Thule”) that is comprised of two discrete size phenotypes. Using whole genome sequencing data of six Thule individu...
Article
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The Great Black-backed Gull Larus marinus is a generalist species that inhabits temperate and arctic coasts of the north Atlantic Ocean. In recent years, there has been growing concern about population declines at local and regional scales; however, there has been no attempt to robustly assess Great Black-backed Gull population trends across its gl...
Article
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Two subspecies of the Great Cormorant breed in Norway, the continental Phalacrocorax carbo sinensis in the south, along the Skagerrak coast, and the marine P. c. carbo from central Norway and northwards. Here we review the information existing until 2017 on population status and trends, breeding performance and diet of these two subspecies in Norwa...
Article
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Timing of breeding, an important driver of fitness in many populations, is widely studied in the context of global change, yet despite considerable efforts to identify environmental drivers of seabird nesting phenology, for most populations we lack evidence of strong drivers. Here we adopt an alternative approach, examining the degree to which diff...
Article
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Human activity in the coastal zone is increasing worldwide, putting a number of seabird species under pressure. Norway is no exception to this development, and with > 35% of the NE Atlantic population of the currently declining European shag (Gulosus aristotelis) population, Norway has an international responsibility for the conservation of this sp...
Data
Supplementary data to "Six pelagic seabird species of the North Atlantic engage in a fly-and-forage strategy during their migratory movements"
Article
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Seabirds are undergoing drastic declines globally and spend the non-breeding season at sea, making it challenging to study the drivers of their survival. Harsh weather and changes in climate conditions can have large impacts on seabird population dynamics through increased mortality. The intensity and persistence of extreme events are forecasted to...
Article
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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.’’ During these, thousands of emaciated seabird carcasses are washed ashore along European and North American coasts. Winter cyclones can therefore shape seabird population dynamics by affect...
Article
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Tracking data of marine predators are increasingly used in marine spatial management. We developed a spatial data set with estimates of the monthly distribution of 6 pelagic seabird species breeding in the Northeast Atlantic. The data set was based on year-round global location sensor (GLS) tracking data of 2356 adult seabirds from 2006-2019 from a...
Article
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Bird migration is commonly defined as a seasonal movement between breeding and non-breeding grounds. It generally involves relatively straight and directed large-scale movements, with a latitudinal change, and specific daily activity patterns comprising less or no foraging and more traveling time. Our main objective was to describe how this general...
Article
Migratory seabirds are exposed to various pollutants throughout their annual cycle. Among them, mercury (Hg) is of particular concern given large impacts on animals’ health. Recent studies suggest that winter is a critical period for seabirds when contamination by Hg can be higher than other times of year. However, individuals within and between sp...
Article
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The conservation of migratory marine species, including pelagic seabirds, is challenging because their movements span vast distances frequently beyond national jurisdictions. Here, we aim to identify important aggregations of seabirds in the North Atlantic to inform ongoing regional conservation efforts. Using tracking, phenology, and population da...
Article
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The factors underlying gene flow and genomic population structure in vagile seabirds are notoriously difficult to understand due to their complex ecology with diverse dispersal barriers and extensive periods at sea. Yet, such understanding is vital for conservation management of seabirds that are globally declining at alarming rates. Here, we eluci...
Article
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Piscivorous wildlife is often perceived as competitors by humans. Great cormorants of the continental subspecies (Phalacrocorax carbo sinensis) in the Baltic and North Sea increase, while local cod (Gadus morhua) stocks decline. In contrast, numbers of the Atlantic subspecies (Phalacrocorax carbo carbo), breeding along the Norwegian and Barents Sea...
Article
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Species breeding at high latitudes face a significant challenge of surviving the winter. Such conditions are particularly severe for diurnal marine endotherms such as seabirds. A critical question is therefore what behavioural strategies such species adopt to maximise survival probability. We tested 3 hypotheses: (1) they migrate to lower latitudes...
Article
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Monitoring plastic in stomachs of beached northern fulmars for OSPAR’s Ecological Quality Objectives (EcoQOs) has been incorporated into the European Marine Strategy Framework Directive (MSFD). This paper aims to provide the appropriate tools to interpret the monitoring results. MSFD requires a data-derived threshold value (Fulmar-TV) representing...
Article
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As more and more species face anthropogenic threats, understanding the causes of population declines in vulnerable taxa is essential. However, long‐term datasets, ideal to identify lasting or indirect effects on fitness measures such as those caused by environmental factors, are not always available. Here we use a single year but multi‐population a...
Article
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Although it has been suggested that plastic may act as a vector for pollutants into the tissue of seabirds, the bioaccumulation of harmful contaminants, such as polybrominated diphenyl ethers (PBDEs), released from ingested plastics is poorly understood. Plastic ingestion by the procellariiform species northern fulmar (Fulmarus glacialis) is well d...
Article
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We present details for the observation of an adult Atlantic Puffin Fratercula arctica collecting food in Lake Linnévatnet (78°02’N 13°48’E), the second largest freshwater lake in the Svalbard archipelago, on 11 August 2020. The bird was seen frequently diving and accumulating fish in its bill. All circumstances considered, we think the bird intende...
Article
Full-text available
We present details for the observation of an adult Atlantic Puffin Fratercula arctica collecting food in Lake Linnévatnet (78°02’N 13°48’E), the second largest freshwater lake in the Svalbard archipelago, on 11 August 2020. The bird was seen frequently diving and accumulating fish in its bill. All circumstances considered, we think the bird intende...
Article
Full-text available
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...
Article
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In recent decades, the population of Black-legged Kittiwake Rissa tridactyla has declined substantially in most parts of the North Atlantic. Concurrently, there has been an increased urbanisation of the species, with Kittiwakes colonising nearshore buildings and other man-made structures. Here we document the prevalence and performance of Kittiwake...
Article
Full-text available
The factors underlying gene flow and genomic population structure in vagile seabirds are notoriously difficult to understand due to their complex ecology with diverse dispersal barriers and extensive periods at sea. Yet, such understanding is vital for conservation management of seabirds that are globally declining at alarming rates. Here, we eluci...
Article
Full-text available
The black-legged kittiwake (Rissa tridactyla, hereafter kittiwake) is a small pelagic seabird and is the most numerous gull species in the world. It has a circumpolar distribution, and breeds in the arctic and boreal zones of the Northern Hemisphere. It’s breeding distribution is widespread and ranges across the North Atlantic from the west coast t...
Article
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Worldwide, incidental bycatch in fisheries is a conservation threat to many seabird species. Although knowledge on bycatch of seabirds has increased in the last decade, most stems from longline fisheries and the impacts of coastal gillnet fisheries are poorly understood. Gillnet fishing for North Atlantic lumpsucker (Cyclopterus lumpus) is one such...
Article
Full-text available
Worldwide, incidental bycatch in fisheries is a conservation threat to many seabird species. Although knowledge on bycatch of seabirds has increased in the last decade, most stems from longline fisheries and the impacts of coastal gillnet fisheries are poorly understood. Gillnet fishing for North Atlantic lumpsucker (Cyclopterus lumpus) is one such...
Article
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The timing of annual events such as reproduction is a critical component of how free‐living organisms respond to ongoing climate change. This may be especially true in the Arctic, which is disproportionally impacted by climate warming. Here, we show that Arctic seabirds responded to climate change by moving the start of their reproduction earlier,...
Article
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The general decline of seabird populations worldwide raises large concerns. Although multiple factors are interacting to cause the observed trends, increased mortality from incidental bycatch in fisheries has proven to be important for many species. However, the bulk of published knowledge is derived from longline fisheries, whereas bycatch in gill...
Data
Formulas for the mean stratified estimator and the GLMM used in the analysis. The mean stratified estimator is an estimator of bycatch per trip across all vessels. The GLMM was parameterised for both diving seabirds and surface feeding seabirds. (DOCX)
Article
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Capsule: Atlantic Puffins Fratercula arctica from Scottish and Norwegian populations were significantly heavier in winter than when rearing chicks. Aims: To compare body masses of Atlantic Puffins on their wintering grounds off the Faroe Islands with those of birds rearing chicks at colonies in Scotland and Norway. Methods: We took standardized mea...
Article
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Reproductive timing in many taxa plays a key role in determining breeding productivity ¹, and is often sensitive to climatic conditions ² . Current climate change may alter the timing of breeding at different rates across trophic levels, potentially resulting in temporal mismatch between the resource requirements of predators and their prey ³ . Thi...
Preprint
Full-text available
Seabirds provide ecosystem services, notably as human food in many Arctic regions, major tourist attractions, as well as being an important link to the Arctic food web and returning nutrients from the oceans to coastal areas. Changes in seabird populations and diversity will affect regional sustainability for Arctic communities and ecosystems. The...
Preprint
Full-text available
Seabirds provide ecosystem services, notably as human food in many Arctic regions, major tourist attractions, as well as being an important link to the Arctic food web and returning nutrients from the oceans to coastal areas. Changes in seabird populations and diversity will affect regional sustainability for Arctic communities and ecosystems. The...
Article
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The typical life history of long-lived seabirds makes their populations extra sensitive to decreases in adult survival. It is therefore important to uncover the extent, causes and consequences of any incident that involves massive die-offs of such species. Towards the end of a stormy winter, large numbers of dead Atlantic Puffins Fratercula arctica...
Article
Which factors shape animals’ migration movements across large geographical scales, how different migratory strategies emerge between populations, and how these may affect population dynamics are central questions in the field of animal migration [1] that only large-scale studies of migration patterns across a species’ range can answer [2]. To addre...
Article
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Both physical and non-physical barriers can restrict gene flow among seabird populations. Understanding the relative importance of non-physical barriers, such as breeding phenology, is key to understanding seabird biodiversity. We investigated drivers of diversification in the Leach's storm-petrel species complex (Hydrobates spp.) by examining popu...
Article
Worldwide, in recent years capture fisheries targeting lower-trophic level forage fish and euphausiid crustaceans have been substantial (∼20 million metric tons [MT] annually). Landings of forage species are projected to increase in the future, and this harvest may affect marine ecosystems and predator-prey interactions by removal or redistribution...
Article
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Carry-over effects, whereby events in one season have consequences in subsequent seasons, have important demographic implications. Although most studies examine carry-over effects across 2 seasons in single populations, the effects may persist beyond the following season and vary across a species’ range. To assess potential carry-over effects acros...
Article
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In this first study of full-grown Black Guillemot Cepphus grylle diet in the Norwegian mainland, 62 of 63 birds caught incidentally in Lumpfish Cyclopterus lumpus gillnets in the north of the country in April-June 2012 and 2013 contained food remains in their stomachs. Fourteen prey taxa were identified and crustaceans were present in 90% of the st...
Article
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In fisheries management, assessing year-class strength and recruitment to commercial stocks is essential, but can be difficult to do for fish species where the young stages are inaccessible to ship-based surveys. This is true for the northeast Arctic saithe Pollachius virens, where the juveniles spend their first years in coastal kelp forests and t...
Technical Report
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Northern fulmars are seabirds which feed exclusively at sea, and as such, they are useful indicators of ocean health. Marine plastic pollution is an ever-increasing and global issue that affects the northern fulmar as they are frequently found to have ingested plastic. In this report we investigate whether the amount of ingested plastic affects the...
Article
With seabird populations in rapid decline, understanding and reducing anthropogenic mortality factors is essential. One such factor is incidental bycatch in fisheries. Here we analyze bycatch in the small-vessel demersal longline fishery for Greenland halibut outside the coast of Northern Norway in 2012–2014, by means of self-reporting from fishers...
Poster
Full-text available
Poster of main findings in Burr, Z. M., Ø Varpe, T. Anker-Nilssen, K. E. Erikstad, S. Descamps, R. T. Barrett, C. Bech, S. Christensen-Dalsgaard, S.-H. Lorentsen, B. Moe, T. K. Reiertsen, and H. Strøm. 2016. Later at higher latitudes: large-scale variability in seabird breeding timing and synchronicity. Ecosphere 7(5):e01283. 10.1002/ecs2.1283 Abst...
Article
Full-text available
In seasonal environments, organisms are expected to optimally schedule reproduction within an annual range of environmental conditions. Latitudinal gradients generate a range of seasonality to which we can expect adaptations to have evolved, and can be used to explore drivers of timing strategies across species' distribution ranges. This study comp...
Article
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Colonial breeding is an evolutionary puzzle, as the benefits of breeding in high densities are still not fully explained. Although the dynamics of existing colonies are increasingly understood, few studies have addressed the initial formation of colonies, and empirical tests are rare. Using a high-resolution larval drift model, we here document tha...
Data
Supplementary Figure 1 and Supplementary Tables 1-4