184 Works

Timing is everything: survival of Atlantic salmon (Salmo salar) postsmolts during events of high salmon lice densities

Thomas Bøhn, Karl Øystein Gjelland, Rosa Serra-Llinares, Bengt Finstad, Raul Primicerio, Rune Nilsen, Ørjan Karlsen, Anne Sandvik, Ove Skilbrei, Kristine Marit Elvik, Øystein Skaala & Pål Bjørn
Atlantic salmon in aquaculture act as reservoir hosts and vectors of parasites like salmon lice and this parasite is shown to harm wild salmonid populations. In the present study, n=29817 tagged Atlantic salmon were studied in four release trials. Half of the released fish were given prophylactic treatment against lice, the other half represented sham control fish. We used a nested design comparing years with low and high lice density and seasonal dynamics in infestation...

Highways associated with expansion of boreal scavengers into the alpine tundra of Fennoscandia

Lars Rød-Eriksen, Johanna Skrutvold, Ivar Herfindal, Henrik Jensen & Nina Elisabeth Eide
1) Habitat fragmentation may affect species distributions through, for example, altered resource availability and shifts in species interactions. Fragmentation by roads has had negative impacts on Fennoscandian alpine ecosystems, with reduction of habitats and connectivity for alpine species. Concurrently, infrastructure development cause influx of subsidies through roadkills and litter, which may facilitate expansion of boreal scavenging species, such as the red fox (Vulpes vulpes), which may intensify negative interactions with alpine species. Hence, understanding the...

Life history genomic regions explain differences in Atlantic salmon marine diet specialization

Tutku Aykanat, Martin Rasmussen, Mikhail Ozerov, Eero Niemelä, Lars Paulin, Juha-Pekka Vaha, Kjetil Hindar, Vidar Wennevik, Torstein Pedersen, Martin Svenning & Craig Primmer
Abstract 1. Animals employ various foraging strategies along their ontogeny to acquire energy, and with varying degree of efficiencies, to support growth, maturation and subsequent reproduction events. Individuals that can efficiently acquire energy early are more likely to mature at an earlier age, as a result of faster energy gain which can fuel maturation and reproduction. 2. We aimed to test the hypothesis that heritable resource acquisition variation that co-varies with efficiency along the ontogeny...

Data from: Dispersal in a house sparrow metapopulation: an integrative case study of genetic assignment calibrated with ecological data and pedigree information

Dilan Saatoglu, Alina K. Niskanen, Markku Kuismin, Peter S. Ranke, Ingerid J. Hagen, Yimen G. Araya-Ajoy, Thomas Kvalnes, Henrik Pärn, Bernt Rønning, Thor Harald Ringsby, Bernt-Erik Sæther, Arild Husby, Mikko J. Sillanpää & Henrik Jensen
Dispersal has a crucial role determining eco-evolutionary dynamics through both gene flow and population size regulation. However, to study dispersal and its consequences, one must distinguish immigrants from residents. Dispersers can be identified using telemetry, capture-mark-recapture (CMR) methods, or genetic assignment methods. All of these methods have disadvantages, such as, high costs and substantial field efforts needed for telemetry and CMR surveys, and adequate genetic distance required in genetic assignment. In this study, we used...

STR data from: Temporal analysis shows relaxed genetic erosion following improved stocking practices in a subarctic transnational brown trout population

Cornelya Klutsch, Simo Maduna, Natalia Poliparkova, Kristin Forfang, Benedicte Beddari, Karl Øystein Gjelland, Paul Eric Aspholm, Per-Arne Amundsen & Snorre Hagen
Maintaining standing genetic variation is a challenge in human-dominated landscapes. We used genetic (i.e., 16 short tandem repeats) and morphological (i.e., length and weight) measurements of 593 contemporary and historical brown trout (Salmo trutta) samples to study fine-scale and short-term impacts of different management practices. These had changed from traditional breeding practices, using the same broodstock for several years, to modern breeding practices, including annual broodstock replacement, in the transnational subarctic Pasvik River. Using population...

Distribution of large carnivores in Europe 2012 - 2016: Distribution maps for Brown bear, Eurasian lynx, Grey wolf, and Wolverine

Petra Kaczensky, John D.C. Linnell, Djuro Huber, Manuela Von Arx, Henrik Andren, Urs Breitenmoser & Luigi Boitani
Regular assessments of species’ status are an essential component of conservation planning and adaptive management. They allow the progress of past or ongoing conservation actions to be evaluated and can be used to redirect and prioritise future conservation actions. Most countries perform periodic assessments for their own national adaptive management procedures or national red lists. Furthermore, the countries of the European Union have to report on the status of all species listed on the directives...

Salmon louse infestation levels on sea trout can be predicted from a hydrodynamic lice dispersal model

Thomas Bøhn, Rune Nilsen, Karl Øystein Gjelland, Martin Biuw, Anne Sandvik, Raul Primicerio, Ørjan Karlsen, Rosa Serra-Llinares, Anne Dagrun Sandvik & Rosa Maria Serra‐Llinares
The abundance of the parasitic salmon louse has increased with the growth in aquaculture of salmonids in open net pens. This represents a threat to wild salmonid populations as well as a key limiting factor for salmon farming. The Norwegian ‘traffic light’ management system for salmon farming aims to increase aquaculture production while securing sustainable wild salmonid populations. However, this system is at present solely focusing on mortality in wild Atlantic salmon, while responses of...

Context dependent fitness costs of reproduction despite stable body mass costs in an Arctic herbivore

Gabriel Pigeon, Steve Albon, Leif Egil Loe, Richard Bischof, Christophe Bonenfant, Mads Farchhammer, Justine Irvine, Erik Ropstad, Vebjorn Veiberg & Audun Stein
1. The cost of reproduction on demographic rates is often assumed to operate through changing body condition. Several studies have found that reproduction depresses body mass more if the current conditions are severe, such as high population densities or adverse weather, than under benign environmental conditions. However, few studies have investigated the association between the fitness and body mass costs of reproduction. 2. Using 25 years of individual-based capture-recapture data from Svalbard reindeer (Rangifer tarandus...

Using genomics to guide seed-sourcing at the right taxonomical level for ecological restoration projects: the complex case of Carex bigelowii s.lat. in Norway

Kristine Bakke Westergaard, Magni Olsen Kyrkjeeide & Marie Kristine Brandrud
There is a growing demand for ecological restoration using suitable seeds following international standards or national legal demands for local seed-sourcing. However, before selecting the appropriate geographic origin of seeds, it is vital to explore taxonomic complexity related to the focal taxa. We used ddRAD-seq to screen genomic diversity within Carex bigelowii s.lat. focussing on Norway. This species complex is considered a candidate for seeding, but presents considerable morphological, ecological, and genetic variation. The genetic...

Data from: Introgression from farmed escapees affects the full life cycle of wild Atlantic salmon

Geir H. Bolstad, Sten Karlsson, Ingerid J. Hagen, Peder Fiske, Kurt Urdal, Harald Sægrov, Bjørn Florø-Larsen, Vegard P. Sollien, Gunnel Østborg, Ola H. Diserud, Arne J. Jensen & Kjetil Hindar
After a half a century of salmon farming, we have yet to understand how the influx of genes from farmed escapees affects the full life history of Atlantic salmon (Salmo salar L.) in the wild. Using scale samples of over 6900 wild adult salmon from 105 rivers, we document that increased farmed genetic ancestry is associated with increased growth throughout life and a younger age at both seaward migration and sexual maturity. There was large...

Age at first reproduction in wolves: different patterns of density dependence for females and males

Camilla Wikenros, Morgane Gicquel, Barbara Zimmermann, Øystein Flagstad & Mikael Åkesson
Age at first reproduction constitutes a key life history trait in animals and is evolutionary shaped by fitness benefits and costs of delayed versus early reproduction. The understanding of how intrinsic and extrinsic changes affects age at first reproduction is crucial for conservation and management of threatened species because of its demographic effects on population growth and generation time. For a period of 40 years in the Scandinavian wolf (Canis lupus) population, including the recolonization...

Time-series covering up to four decades reveals major changes and drivers of marine growth and proportion of repeat spawners in an Atlantic salmon population

Alison Harvey, Øystein Skaala, Reidar Borgstrøm, Per Tommy Fjeldheim, Kaja Fjeldheim, Kjell Utne, Ingrid Johnsen, Peder Fiske, Synne Winterthun, Sofie Knutar, Harald Sægrov, Kurt Urdal & Kevin Glover
1. Wild Atlantic salmon populations have declined in many regions and are affected by diverse natural and anthropogenic factors. To facilitate management guidelines, precise knowledge of mechanisms driving population changes in demographics and life history traits is needed. 2. Our analyses were conducted on a) age and growth data from scales of salmon caught by angling in the river Etneelva, Norway, covering smolt year classes from 1980 to 2018, b) extensive sampling of the whole...

Variation and correlation in the timing of breeding of North Atlantic seabirds across multiple scales

Katharine Keogan, Francis Daunt, Sarah Wanless, Richard Phillips, David Alvarez, Tycho Anker-Nilssen, Robert Barrett, Claus Bech, Peter Becker, Per-Arvid Berglund, Sandra Bouwhuis, Zofia Burr, Olivier Chastel, Signe Christensen-Dalsgaard, Sébastien Descamps, Tony Diamond, Kyle Elliott, Kjell Einar Erikstad, Mike Harris, Jonas Hentati-Sundberg, Martin Heubeck, Magdalene Langset, Svein Lorentsen, Heather Major, Mark Mallory … & Stephen Kress
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 different populations positively covary in their annual phenology to infer whether phenological responses to environmental drivers are likely to be (i) shared across...

Smolt outmigration timing in Norway

Robert Lennox, Knut Vollset, Ola Ugedal, Anders Lamberg, Øystein Skaala, Anne Sandvik, Harald Saegrov, Torstein Kristiensen, Arne Jensen, Tormond Haraldstad & Bjørn Barlaup
Aim - Accurate predictions about transition timing of salmon smolts between freshwater and marine environments are key to effective management. We aimed to use available data on Atlantic salmon smolt migration to predict the emigration timing in rivers throughout Norway. Location - In this study, we used data outmigration timing data of Atlantic salmon (Salmo salar) smolts from 41 rivers collected from 1984-2018 to make a predictive model for the timing of out-migrating salmon smolts...

Genotype data from: Restoration of transborder connectivity for Fennoscandian brown bears (Ursus arctos)

Alexander Kopatz, Kleven Oddmund, Kojola Ilpo, Aspi Jouni, Anita J. Norman, Göran Spong, Niclas Gyllenstrand, Love Dalén, Ida Fløystad, Snorre B. Hagen, Jonas Kindberg & Øystein Flagstad
Knowledge about the connectivity among natural populations is essential to identify management units for effective conservation actions. Conservation-minded management has led to the recovery of large carnivore populations in northern Europe, possibly restoring connectivity between the two separated, but expanding brown bear (Ursus arctos) populations on the Scandinavian peninsula to the west and Karelia, a part of the large Eurasian population, to the east. The degree of connectivity between these populations has been poorly understood,...

Cercarial behaviour alters the consumer functional response of three-spined sticklebacks

Ana Born-Torrijos, Rachel Paterson, Gabrielle Van Beest, Tereza Vyhlídalová, Eirik Haugstvedt Henriksen, Rune Knudsen, Roar Kristoffersen, Per-Arne Amundsen & Miroslava Soldánová
1. Free-living parasite life stages may contribute substantially to ecosystem biomass and thus represent a significant source of energy flow when consumed by non-host organisms. However, ambient temperature and the predator’s own infection status may modulate consumption rates towards parasite prey. 2. We investigated the combined effects of temperature and predator infection status on the consumer functional response of three-spined sticklebacks towards the free-living cercariae stages of two common freshwater trematode parasites (Plagiorchis, Trichobilharzia). 3....

European shag provisioning foraging dives

Astrid Carlsen, Jonathan Wright & Svein-Håkon Lorentsen
Foraging dives in birds and mammals involve complex physiological and behavioural adaptations to cope with the breaks in normal respiration. Optimal dive strategies should maximise the proportion of time spent under water actively foraging versus the time spent on the surface. Oxygen loading and carbon-dioxide dumping carried out on the surface could involve recovery from the consequences of the last dive and/or preparation in anticipation of the next dive depth and duration. However, few studies...

The legacy of forest disturbance on stream ecosystem functioning

André Frainer & Brendan McKie
1. Forest clearance is a pervasive disturbance worldwide, but many of its impacts are regarded as transient, diminishing in intensity as forest recovers. However, forests can take decades to centuries to recover after severe disturbances, and temporal lags in recovery of ecosystem properties for different forest habitats are mostly unknown. This includes forest streams, where most studies of the impacts of forest clearance are restricted to the first years of recovery, typically finding that temporary...

Effects of disturbance on plant regrowth along snow pack gradients in alpine habitats

Marianne Evju, Dagmar Hagen & Annika Hofgaard
Human disturbance in alpine habitats is expected to increase, and improved knowledge of short-term recovery after disturbance events is necessary to interpret vegetation responses and formulate planning and mitigation efforts. The ability of a plant community to return to its original state after a disturbance (community resilience) depends on species composition and environmental conditions. The aim of this study is to analyze initial short-term effects of disturbance in alpine plant communities in contrasting climates (oceanic...

Data from: Stress‐induced secondary leaves of a boreal deciduous shrub (Vaccinium myrtillus) overwinter then regain activity the following growing season

Jarle W. Bjerke, Grzegorz Wierzbinski, Hans Tømmervik, Gareth K. Phoenix & Stef Bokhorst
The ericoid shrub Vaccinium myrtillus is one of several deciduous boreal plants that respond to larval defoliation by compensatory production of a new set of leaves within the same growing season soon after defoliation. This new set is termed as ‘secondary leaves’. The physiological performance and longevity of secondary leaves is poorly understood. Following a multi‐year larval outbreak in boreal Norway, we therefore monitored the fate of the secondary leaves from 2014 to 2016. We...

Data from: Determinants of age at first reproduction and lifetime breeding success revealed by full paternity assignment in a male ungulate

Stine S. Markussen, Ivar Herfindal, Anne Loison, Erling J. Solberg, Hallvard Haanes, Knut H. Røed, Morten Heim, Bernt-Erik Sæther & Bernt-Erik Saether
Age at first reproduction is an important determinant of individual variation in reproductive success in ungulates, but few studies have examined its relationship with later fitness-related traits in males. We used a long-term individual based study of a harvested moose population to quantify the individual reproductive performance and survival of males, as well as to examine the determinants of age at first reproduction and consequences of age at first reproduction on lifetime breeding success. The...

Data from: Lake size and fish diversity determine resource use and trophic position of a top predator in high-latitude lakes

Antti P. Eloranta, Kimmo K. Kahilainen, Per-Arne Amundsen, Rune Knudsen, Chris Harrod & Roger I. Jones
Prey preference of top predators and energy flow across habitat boundaries are of fundamental importance for structure and function of aquatic and terrestrial ecosystems, as they may have strong effects on production, species diversity, and food-web stability. In lakes, littoral and pelagic food-web compartments are typically coupled and controlled by generalist fish top predators. However, the extent and determinants of such coupling remains a topical area of ecological research and is largely unknown in oligotrophic...

Data from: Mismatch between fishway operation and timing of fish movements: a risk for cascading effects in partial migration systems

Casper H. A. Van Leeuwen, Jon Museth, Odd Terje Sandlund, Tore Qvenild & Leif Asbjørn Vøllestad
Habitat fragmentation is a growing problem worldwide. Particularly in river systems, numerous dams and weirs hamper the movement of a wide variety of species. With the aim to preserve connectivity for fish, many barriers in river systems are equipped with fishways (also called fish passages or fish ladders). However, few fishways provide full connectivity. Here we hypothesized that restricted seasonal opening times of fishways can importantly reduce their effectiveness by interfering with the timing of...

Data from: From steps to home range formation: species-specific movement upscaling among sympatric ungulates

Zulima Tablado, Eloy Revilla, Dominique Dubray, Sonia Saïd, Daniel Maillard & Anne Loison
Animals move to interact with the environment in order to find food resources and cover. Intrinsic characteristics affecting feeding and antipredatory strategies likely shape variation in movement patterns and home range formation between individuals, populations and species. Browsing herbivores selectively forage on patchily distributed resources in areas with more canopy cover, whereas mixed feeders and grazers feed on more open grasslands and tend to aggregate as an antipredatory strategy. We therefore predicted that at small...

Data from: On fitness and partial migration in a large herbivore – migratory moose have higher reproductive performance than residents

Christer Moe Rolandsen, Erling J. Solberg, Bengt-Erik Sæther, Bram Van Moorter, Ivar Herfindal, Kari Bjørneraas & Bernt-Erik Saether
Partially migratory populations comprise both resident and migratory individuals. These tactics may coexist if their demographic contribution to future generations (i.e. fitness) are equal or vary temporally with environmental conditions, or if individuals switch between being migrant and resident. Alternatively, the choice of movement tactic can be based on individual attributes such as age, competitive ability or personality. In the latter cases, the two tactics are not expected to have similar average fitness. In this...

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