Browsing NTNU Open by Author "Kvalnes, Thomas"
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Multiple aspects of plasticity in clutch size vary among populations of a globally distributed songbird
Westneat, David; Bokony, Veronika; Burke, Terry; Chastel, Olivier; Jensen, Henrik; Kvalnes, Thomas; Lendvai, Adam Z.; Liker, Andras; Mock, Douglas; Schroeder, Julia; Schwagmeyer, P. L.; Sorci, Gabriele; Stewart, Ian R. K. (Journal article, 2014)Plasticity in life-history characteristics can influence many ecological and evolutionary phenomena, including how invading organisms cope with novel conditions in new locations or how environmental change affects organisms ... -
Nest Microclimate in Relation to Maternal Phenotypic Quality and Reproductive Success in a Wild Population of House Sparrows (Passer domesticus)
Thurmann-Nielsen, Cathrine (Master thesis, 2019)En bedre forståelse av faktorene som påvirker produksjonen av flyvedyktige unger og rekrutterende fugler er viktig for å forstå økologiske og evolusjonære prosesser. De tidligste livsstadiene er kritiske for overlevelse, ... -
Offspring fitness and the optimal propagule size in a fluctuating environment
Kvalnes, Thomas; Røberg, Anja Ås; Jensen, Henrik; Holand, Håkon; Pärn, Henrik; Sæther, Bernt-Erik; Ringsby, Thor Harald (Journal article; Peer reviewed, 2018) -
On being the right size: Increased body size is associated with reduced telomere length under natural conditions
Ringsby, Thor Harald; Jensen, Henrik; Pärn, Henrik; Kvalnes, Thomas; Boner, Winnie; Gillespie, Robert; Holand, Håkon; Hagen, Ingerid Julie; Rønning, Bernt; Sæther, Bernt-Erik; Monaghan, Pat (Journal article, 2015)Evolution of body size is likely to involve trade-offs between body size, growth rate and longevity. Within species, larger body size is associated with faster growth and ageing, and reduced longevity, but the cellular ... -
Parasite prevalence increases with temperature in an avian metapopulation in northern Norway
Holand, Håkon; Jensen, Henrik; Kvalnes, Thomas; Tufto, Jarle; Pärn, Henrik; Sæther, Bernt-Erik; Ringsby, Thor Harald (Peer reviewed; Journal article, 2019)Climate and weather conditions may have substantial effects on the ecology of both parasites and hosts in natural populations. The strength and shape of the effects of weather on parasites and hosts are likely to change ... -
Predator-Induced Selection on Phenotypes by Sparrowhawks (Accipiter nisus) in House sparrows (Passer domesticus)
Bjørsrud, Maren Sofie (Master thesis, 2022)Predasjon kan påvirke fenotypisk og genotypisk distribuering av trekk i byttedyret, samt ha en innflytelse på demografisk struktur og variasjon i mortalitet ved tid og rom. Denne studien undersøker hvordan predasjon av ... -
Reversal of response to artificial selection on body size in a wild passerine bird
Kvalnes, Thomas; Ringsby, Thor Harald; Jensen, Henrik; Hagen, Ingerid Julie; Rønning, Bernt; Pärn, Henrik; Holand, Håkon; Engen, Steinar; Sæther, Bernt-Erik (Journal article, 2017)A general assumption in quantitative genetics is the existence of an intermediate phenotype with higher mean individual fitness in the average environment than more extreme phenotypes. Here we investigate the evolvability ... -
Sensitivity analysis of effective population size to demographic parameters in house sparrow populations
Stubberud, Marlene Wæge; Myhre, Ane Marlene; Holand, Håkon; Kvalnes, Thomas; Ringsby, Thor Harald; Sæther, Bernt-Erik; Jensen, Henrik (Journal article, 2017)The ratio between the effective and the census population size, (math formula), is an important measure of the long-term viability and sustainability of a population. Understanding which demographic processes that affect ... -
Spatial variation in senescence rates in a bird metapopulation
Holand, Håkon; Kvalnes, Thomas; Gamelon, Marlène; Tufto, Jarle; Jensen, Henrik; Pärn, Henrik; Ringsby, Thor Harald; Sæther, Bernt-Erik (Journal article, 2016)Investigating factors which affect the decline in survival with age, i.e. actuarial senescence, is important in order to understand how demographic rates vary in wild populations. Although the evidence for the occurrence ... -
Spatial variation in the evolutionary potential and constraints of basal metabolic rate and body mass in a wild bird
Nafstad, Ådne Messel; Rønning, Bernt; Aase, Kenneth; Ringsby, Thor Harald; Hagen, Ingerid Julie; Ranke, Peter Sjolte; Kvalnes, Thomas; Stawski, Clare; Räsänen, Katja; Sæther, Bernt-Erik; Muff, Stefanie; Jensen, Henrik (Peer reviewed; Journal article, 2023)An organism's energy budget is strongly related to resource consumption, performance, and fitness. Hence, understanding the evolution of key energetic traits, such as basal metabolic rate (BMR), in natural populations is ... -
Spatiotemporal Variation and Fitness Consequences of Blood Hemoglobin Concentration in free-living House Sparrow (Passer domesticus) Nestlings
Jakobsen, Marte (Master thesis, 2018)Studies have suggested that variation in hemoglobin concentration among individuals can be used as an indicator of individual condition as it reflects the amount of oxygen that is supplied to the tissues. Thus, it is ... -
Spatiotemporal variation in laying date and its impact on reproductive success in house sparrows (Passer domesticus)
Johansen, Sonja Kristina Norum (Master thesis, 2018)Timing of breeding is an important determinant of reproductive success for animals living in seasonal environments. Understanding the factors affecting reproductive processes are necessary to predict how populations may ... -
Stabilizing selection and adaptive evolution in a combination of two traits in an arctic ungulate
Holand, Håkon; Kvalnes, Thomas; Røed, Knut; Holand, Øystein; Sæther, Bernt-Erik; Kumpula, Jukka (Journal article; Peer reviewed, 2020)Stabilizing selection is thought to be common in wild populations and act as one of the main evolutionary mechanisms, which constrain phenotypic variation. When multiple traits interact to create a combined phenotype, ... -
The effect of arthropod availability on reproductive phenology and success in a multi-brooded passerine Passer domesticus
Julseth, Martin Gjestrud (Master thesis, 2019)Leddyr er en viktig proteinkilde under den tidlige veksten og utviklingen til mange små tetrapoder, derunder reirungene til mange arter av spurvefugler. Sesongvariasjonen i leddyrsamfunn forventes derfor å være en viktig ... -
The Effects of Diet and Weather on Early-life Growth and Survival in Atlantic Puffin Nestlings in Northern Norway
Oddvik, Vilde Jonasson (Master thesis, 2023)Den hurtige nedgangen i sjøfuglpopulasjoner i verden de siste tiårene har gjort forskning på effekter av klimaendringer og andre potensielle trusler mot sjøfulger mer og mer viktig. Enkelte hekkeparametere hos sjøfugler ... -
The influence of arthropods availability on fledgling morphology and reproductive success in wild house sparrows
Saugestad, Margrete (Master thesis, 2023)Over hele verden rapporteres det om nedgang i antall innsekter samt fugler i kulturlandskapet. Redusert tilgjengelighet av leddyr har vært foreslått som en mulig årsak til nedgangen av insektspisende fugler gjennom ... -
Variation in generation time reveals density regulation as an important driver of pace of life in a bird metapopulation
Araya-Ajoy, Yimen; Niskanen, Alina Katariina; Froy, Hannah; Ranke, Peter Sjolte; Kvalnes, Thomas; Rønning, Bernt; Pepke, Michael Le; Jensen, Henrik; Ringsby, Thor Harald; Sæther, Bernt-Erik; Wright, Jonathan (Journal article; Peer reviewed, 2021)Generation time determines the pace of key demographic and evolutionary processes. Quantified as the weighted mean age at reproduction, it can be studied as a life-history trait that varies within and among populations and ...