Publications by authors named "Morten Heim"
Article Synopsis
- Caring for newborns limits mammalian females' ability to gather resources, especially during the energy-demanding early lactation period.
- Different ungulates have developed various strategies for protecting their vulnerable newborns, from staying hidden to being mobile, which can influence their mothers' movement patterns.
- A study of 54 populations of 23 ungulate species shows that maternal movements are affected by the resource availability and type of neonatal strategy, highlighting the importance of these tactics in understanding how species adapt to environmental changes.
Article Synopsis
- Wildlife tagging is important for understanding animal behavior and ecology, but the stress from this process can affect their movement and activity levels after being released.
- An analysis of 1585 individuals from 42 mammal species showed that over 70% exhibited significant behavioral changes post-tagging, with herbivores traveling farther while omnivores and carnivores were less active initially.
- Recovery from stress was generally quick, typically within 4-7 days, and animals in areas with a high human presence adapted faster, suggesting that tracking durations should be longer and consider species and location when designing studies.
Article Synopsis
- Understanding the nutritional properties of foods is crucial for managing wildlife populations, specifically moose, as they balance macronutrients like protein and carbohydrates while foraging.
- A study in Norway highlighted that moose primarily derive their energy from carbohydrates (74.2%), mostly from deciduous tree browse, particularly willows, which made up 51% of their average diet over a 5-day period in summer.
- Moose regulate their nutrient intake by choosing foods that closely match their macronutrient targets and demonstrated flexibility in their feeding strategies, indicating that even small variations in diet can help them achieve nutritional balance.
COVID-19 lockdowns in early 2020 reduced human mobility, providing an opportunity to disentangle its effects on animals from those of landscape modifications. Using GPS data, we compared movements and road avoidance of 2300 terrestrial mammals (43 species) during the lockdowns to the same period in 2019. Individual responses were variable with no change in average movements or road avoidance behavior, likely due to variable lockdown conditions.
View Article and Find Full Text PDFLandscape changes are happening at an unprecedented pace, and together with high levels of wildlife harvesting humans have a large effect on wildlife populations. A thorough knowledge of their combined influence on individual fitness is important to understand factors affecting population dynamics. The goal of the study was to assess the individual consistency in the use of risky habitat types, and how habitat use was related to fitness components and life-history strategies.
View Article and Find Full Text PDFLevels of random genetic drift are influenced by demographic factors, such as mating system, sex ratio and age structure. The effective population size (N ) is a useful measure for quantifying genetic drift. Evaluating relative contributions of different demographic factors to N is therefore important to identify what makes a population vulnerable to loss of genetic variation.
View Article and Find Full Text PDFTrade-offs between fitness-related traits are predicted from the principle of resource allocation, where increased fecundity or parental investment leads to reduced future reproduction or survival. However, fitness traits can also be positively correlated due to individual differences (e.g.
View Article and Find Full Text PDFMechanisms reducing inbreeding are thought to have evolved owing to fitness costs of breeding with close relatives. In small and isolated populations, or populations with skewed age- or sex distributions, mate choice becomes limited, and inbreeding avoidance mechanisms ineffective. We used a unique individual-based dataset on moose from a small island in Norway to assess whether inbreeding avoidance was related to population structure and size, expecting inbreeding avoidance to be greater in years with larger populations and even adult sex ratios.
View Article and Find Full Text PDFInbreeding can affect fitness-related traits at different life history stages and may interact with environmental variation to induce even larger effects. We used genetic parentage assignment based on 22 microsatellite loci to determine a 25 year long pedigree for a newly established island population of moose with 20-40 reproducing individuals annually. We used the pedigree to calculate individual inbreeding coefficients and examined for effects of individual inbreeding (f) and heterozygosity on fitness-related traits.
View Article and Find Full Text PDFIn seasonal environments, timing of reproduction is an important fitness component. However, in ungulates, our understanding of this biological process is limited. Here we analyze how age and body mass affect spatiotemporal variation in timing of ovulation of 6,178 Norwegian moose.
View Article and Find Full Text PDFArticle Synopsis
- The study examines how body mass at 8 months affects adult size in moose on Vega Island, Norway, highlighting that neither males nor females could achieve catch-up growth.
- Findings suggest that variations in adult body mass may stem from factors like mother age and birth timing, reflecting different growth strategies between genders.
- The research implies that females may struggle to compensate for early body mass disadvantages if they delay reproduction, contributing to a weak capacity for compensatory growth in moose.
A general feature of the demography of large ungulates is that many demographic traits are dependent on female body mass at early ages. Thus, identifying the factors affecting body mass variation can give important mechanistic understanding of demographic processes. Here we relate individual variation in autumn and winter body mass of moose calves living at low density on an island in northern Norway to characteristics of their mother, and examine how these relationships are affected by annual variation in population density and climate.
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