Browsing NTNU Open by Author "Ringsby, Thor Harald"
Now showing items 1-20 of 38
-
Causes and Consequences of Breeding Synchrony in the Snow Bunting (Plectrophenax nivalis )
Skøien, Elida Arstad (Master thesis, 2015)Climate warming is happening rapidly in the Arctic and migratory birds are among the species expected to be affected by the predicted shifts in spring phenology. Using time-series data (1998 - 2014) from a population of ... -
Characterizing morphological (co)variation using structural equation models: Body size, allometric relationships and evolvability in a house sparrow metapopulation
Araya-Ajoy, Yimen; Ranke, Peter Sjolte; Kvalnes, Thomas; Rønning, Bernt; Holand, Håkon; Myhre, Ane Marlene; Pärn, Henrik; Jensen, Henrik; Ringsby, Thor Harald; Sæther, Bernt-Erik; Wright, Jonathan (Peer reviewed; Journal article, 2019)Body size plays a key role in the ecology and evolution of all organisms. Therefore, quantifying the sources of morphological (co)variation, dependent and independent of body size, is of key importance when trying to ... -
Climate trends, weather fluctuations and calving phenology in Svalbard reindeer (Rangifer tarandus platyrhynchus)
Danielsen, Preben (Master thesis, 2016)Reproduction is known to be one of the most energetically demanding processes in the life of an organism, and in seasonal environments, vertebrate offspring production is therefore timed to coincide with the annual peak ... -
Controlling for P-value inflation in allele frequency change in experimental evolution and artificial selection experiments
Kemppainen, Petri; Rønning, Bernt; Kvalnes, Thomas; Hagen, Ingerid Julie; Ringsby, Thor Harald; Billing, Anna Maria; Pärn, Henrik; Lien, Sigbjørn; Husby, Arild; Sæther, Bernt-Erik; Jensen, Henrik (Journal article; Peer reviewed, 2017)Experimental evolution studies can be used to explore genomic response to artificial and natural selection. In such studies, loci that display larger allele frequency change than expected by genetic drift alone are assumed ... -
Demographic and genetic consequences of dispersal in house sparrows
Ranke, Peter Sjolte (Doctoral theses at NTNU;2019:24, Doctoral thesis, 2019)The importance of dispersal in population dynamics is widely acknowledged. Key to understand population consequences of dispersal is by quantifying the demographic and genetic contribution from dispersers. The influence ... -
Demographic determinants of population growth rate in willow ptarmigan (Lagopus lagopus) in Lierne, central Norway
Stavnås, Veronica Myhr (Master thesis, 2018)Willow ptarmigan (Lagopus lagopus) populations in Norway have declined during the last decade and the species was included in the Norwegian Red list in 2015 as near threatened . Accordingly, it is important to identify ... -
Demographic influences of translocated individuals on a resident population of house sparrows
Ranke, Peter Sjolte; Skjelseth, Sigrun; Pärn, Henrik; Herfindal, Ivar; Borg Pedersen, Åsa Alexandra; Stokke, Bård Gunnar; Kvalnes, Thomas; Ringsby, Thor Harald; Sæther, Bernt-Erik; Jensen, Henrik (Journal article; Peer reviewed, 2017)Translocation of individuals from source populations to augment small populations facing risk of extinction is an important conservation tool. Here we examine sex-specific differences between resident and translocated house ... -
Effects of population characteristics and structure on estimates of effective population size in a house sparrow metapopulation
Baalsrud, Helle Tessand; Sæther, Bernt-Erik; Hagen, Ingerid Julie; Myhre, Ane Marlene; Ringsby, Thor Harald; Pärn, Henrik; Jensen, Henrik (Journal article, 2014)Effective population size (Ne) is a key parameter to understand evolutionary processes and the viability of endangered populations as it determines the rate of genetic drift and inbreeding. Low Ne can lead to inbreeding ... -
Effects of Variation in Egg Size on Maternal Fitness in a Population of House Sparrows (Passer domesticus)
Krogfjord, Mari (Master thesis, 2018)According to life history theory individuals will optimize investment into growth, reproduction and self-maintenance. Egg size is an important life history trait predicted to have an optimum that maximizes maternal individual ... -
Effects of Variation in Egg Size on Offspring Fitness in Populations of House Sparrow (Passer domesticus)
Røberg, Anja Ås (Master thesis, 2015)1. Egg size represents an important life-history trait, which may have effects on the fitness of offspring. The effect of variation in egg size on offspring fitness has been studied within many taxa, but there is still a ... -
Endoparasite infection has both short- and long-term negative effects on reproductive success of female house sparrows, as revealed by faecal parasitic egg counts
Holand, Håkon; Jensen, Henrik; Tufto, Jarle; Pärn, Henrik; Sæther, Bernt-Erik; Ringsby, Thor Harald (Journal article; Peer reviewed, 2015)Parasites have the potential to severely reduce host reproductive success. However, the effects of endoparasites on reproductive success have not received the same amount of attention as the effects of parasites on host ... -
Exploring Moulting Common Eider (Somateria mollissima) Escape Responses towards Ship Traffic.
Skei, Jørgen (Master thesis, 2014)1. The construction of bottom dwelling offshore wind farms in shallow waters is expected to interfere with seabird feeding and moulting habitats. This study focus on how the disturbance from ship traffic associated with ... -
Foraging behaviour of the European shag during early chick-rearing period; do they follow the marginal value theorem?
De Rijcke, Sandra (Master thesis, 2015)1. Optimal allocation of food is essential during the breeding season, when animals have to provide food for themselves and their chicks. As central place foragers, seabirds forage away from the nest and have to balance ... -
Genetic variability and structure of the water vole Arvicola amphibius across four metapopulations in northern Norway
Melis, Claudia; Borg, Åsa Alexandra; Jensen, Henrik; Bjørkvoll, Eirin Marie; Ringsby, Thor Harald; Sæther, Bernt-Erik (Journal article; Peer reviewed, 2013)Water vole Arvicola amphibius populations have recently experienced severe decline in several European countries as a consequence of both reduction in suitable habitat and the establishment of the alien predator American ... -
Identifying Conservative Criteria for (environmental) Assessments of Vulnerability;: Seabirds and Offshore Wind Farms as a Case Study
Gressetvold, Marit (Master thesis, 2013)The approach is based on four criterias; 1) elasticity of adult and juvenile survival on population growth rate, 2) redlist status and 3) local abundances and 4) flight properties. I also investigated whether the different ... -
Indirect social effects of the individual strategy in producer-scrounger foraging interactions
Pettersen, Nils Håkon (Master thesis, 2017)When animals interact socially they experience and react to phenotypes of their social partners. Such interactions can affect behaviours and fitness, and therefore opponent effects (i.e. indirect social effects) can maintain ... -
Individual variation and indirect social effects in Producer-Scrounger behavior in the House Sparrow, Passer domesticus
Mohammad, Talal (Master thesis, 2018)Game theory is a scenario where, at its simplest, two alternative tactics may yield different costs and benefits. Many organisms are tied to a dynamic environment where the actions, social behaviors, or even presence of ... -
Inferences of genetic architecture of bill morphology in house sparrow using a high-density SNP array point to a polygenic basis
Lundregan, Sarah; Hagen, Ingerid Julie; Gohli, Jostein; Niskanen, Alina Katariina; Kemppainen, Petri; Ringsby, Thor Harald; Kvalnes, Thomas; Pärn, Henrik; Rønning, Bernt; Holand, Håkon; Ranke, Peter Sjolte; Båtnes, Anna Solvang; Selvik, Linn-Karina M.; Lien, Sigbjørn; Sæther, Bernt-Erik; Husby, Arild; Jensen, Henrik (Journal article; Peer reviewed, 2018)Understanding the genetic architecture of quantitative traits can provide insights into the mechanisms driving phenotypic evolution. Bill morphology is an ecologically important and phenotypically variable trait, which is ... -
Insights into the genetic architecture of morphological and sexually selected traits in two passerine bird species
Silva, Catarina; McFarlane, S. Eryn; Hagen, Ingerid Julie; Rönnegård, Lars; Billing, Anna; Kvalnes, Thomas; Kemppainen, Petri; Rønning, Bernt; Ringsby, Thor Harald; Sæther, Bernt-Erik; Qvarnström, Anna; Ellegren, Hans; Jensen, Henrik; Husby, Arild (Journal article; Peer reviewed, 2017)Knowledge about the underlying genetic architecture of phenotypic traits is needed to understand and predict their evolutionary dynamics. The number of causal loci underlying most phenotypic traits, the magnitude of their ... -
Is basal metabolic rate associated with recruit production and survival in free-living house sparrows?
Rønning, Bernt; Broggi, Juli; Bech, Claus; Moe, Børge; Ringsby, Thor Harald; Pärn, Henrik; Hagen, Ingerid Julie; Sæther, Bernt-Erik; Jensen, Henrik; Grindstaff, Jennifer (Journal article; Peer reviewed, 2016)Life history theory predicts that available energy is limited and needs to be allocated among different processes such as growth, reproduction and self-maintenance. Basal metabolic rate (BMR), a common measure of an animal's ...