John Odden

• PhD
• Senior Researcher at Norwegian Institute for Nature Research

Mammalian dispersal is characterized by long‐distance movements, and whether dispersal is sex‐dependent and occurs at pre‐saturation densities affects colonization speed and concurrent pathogen spread. In Scandinavia, Sweden classifies wild boar Sus scrofa as a native species and retains high densities, while Norwegian authorities considers it an a...

Domestic cats (Felis catus), both feral animals and pets, are a major threat to biodiversity. While domestic cats are closely associated with human residences and activity, they also range into and impact natural areas. We still know little about how free‐ranging cats use natural and semi‐natural areas. We quantified cat occurrence at 405 forest si...

Survival and cause‐specific mortality rates are vital for evidence‐based population forecasting and conservation, particularly for large carnivores, whose populations are often vulnerable to human‐caused mortalities. It is therefore important to know the relationship between anthropogenic and natural mortality causes to evaluate whether they are ad...

The estimation of foraging parameters is fundamental for understanding predator ecology. Predation and feeding can vary with multiple factors, such as prey availability, presence of kleptoparasites and human disturbance. However, our knowledge is mostly limited to local scales, which prevents studying effects of environmental factors across larger...

The diel activity patterns of animals convey information about physiology, ecological niches and animal behaviour relevant for both applied conservation and more theoretical research. However, these patterns are challenging to study in the field. The current gold‐standard approach to quantify movements and activity patterns of medium to large wildl...

Interactions among coexisting mesocarnivores can be influenced by different factors such as the presence of large carnivores, land‐use, environmental productivity, or human disturbance. Disentangling the relative importance of bottom‐up and top‐down processes can be challenging, but it is important for biodiversity conservation and wildlife managem...

Interactions among coexisting mesocarnivores can be influenced by different factors such as the presence of large carnivores, land-use, environmental productivity, or human disturbance. Disentangling the relative importance of bottom-up and top-down processes can be challenging, but it is important for biodiversity conservation and wildlife managem...

Aim: The increasing availability of animal tracking datasets collected across many sites provides new opportunities to move beyond local assessments to enable detailed and consistent habitat mapping at biogeographical scales. However, integrating wildlife datasets across large areas and study sites is challenging, as species' varying responses to d...

Local adaptation to annually changing environments has evolved in numerous species. Seasonal coat colour change is an adaptation that has evolved in multiple mammal and bird species occupying areas that experience seasonal snow cover. It has a critical impact on fitness as predation risk may increase when an individual is mismatched against its hab...

The European pine marten Martes martes is often associated with late seral stage coniferous forest stands. Earlier research has indicated that this species may be negatively influenced by clearcutting practices. However, the effects of current clearcutting methods on pine marten occurrence in conjunction with changing environmental conditions are n...

Local adaptation to annually changing environments has evolved in numerous species. Seasonal coat colour change is an adaptation that has evolved in multiple mammal and bird species occupying areas that experience seasonal snow cover. It has a critical impact on fitness as predation risk may increase when an individual is mismatched against its hab...

Context Adjustments in habitat use by large carnivores can be a key factor facilitating their coexistence with people in shared landscapes. Landscape composition might be a key factor determining how large carnivores can adapt to occurring alongside humans, yet broad-scale analyses investigating adjustments of habitat use across large gradients of...

Kill rates are a central parameter to assess the impact of predation on prey species. An accurate estimation of kill rates requires a correct identification of kill sites, often achieved by field‐checking GPS location clusters (GLCs). However, there are potential sources of error included in kill‐site identification, such as failing to detect GLCs...

The ecology and evolution of reproductive timing and synchrony has been a topic of great interest in evolutionary ecology for decades. Originally motivated by questions related to behavioural and reproductive adaptation to environmental conditions, the topic has acquired new relevance in the face of climate change. However, there has been relativel...

Brøseth, H., Odden, J. & Nilsen, E. B. 2022. Number of family groups, population estimate and population development of lynx in Norway for 2022. - NINA Report 2155. Norwegian Institute for Nature Research Abstract: The national monitoring program for large carnivores follows the Norwegian lynx population through the survey of family groups (adult f...

ContextBehavioral adjustments by large carnivores can be a key factor facilitating their coexistence with people in shared landscapes. Landscape composition might be a key factor determining how large carnivores can adapt to occurring alongside humans, yet broad-scale analyses investigating adjustments of habitat use across large gradients of human...

Aim Macroecological studies that require habitat suitability data for many species often derive this information from expert opinion. However, expert‐based information is inherently subjective and thus prone to errors. The increasing availability of GPS tracking data offers opportunities to evaluate and supplement expert‐based information with deta...

Outdoor recreation is increasing and affects habitat use and selection by wildlife. These effects are challenging to study, especially for elusive species with large spatial requirements, as it is hard to obtain reliable proxies of recreational intensity over extensive areas. Commonly used proxies, such as the density of, or distance to, hiking pat...

Recovering or threatened carnivore populations are often harvested to minimise their impact on human activities, such as livestock farming or game hunting. Increasingly, harvest quota decisions involve a set of scientific, administrative and political institutions operating at national and sub‐national levels whose interactions and collective decis...

Coat coloration plays an important role in communication, camouflage, and sexual selection in animals. Genetic mutations can lead to anomalous colorations such as melanism and leucism, where animals appear, respectively, darker or lighter than normal. Reporting abnormal coloration in wild animals is an important first step to understand the distrib...

A central goal in camera‐trapping (CT) studies is to maximize detection probability and precision of occupancy estimates while minimizing the number of CTs to reduce equipment and labor costs. Few studies, however, have examined the effect of CT number on detection probability. Moreover, historically, most studies focused on a specific species and...

Are instrumented animals representative of the population, given the potential bias caused by selective sampling and the influence of capture, handling and wearing bio-loggers? The answer is elusive owing to the challenges of obtaining comparable data from individuals with and without bio-loggers. Using non-invasive genetic data of a large carnivor...

Surveying and monitoring biodiversity using new technology: eDNA and camera trapping. NINA Report 1962. Norwegian Institute for Nature Research. Norway has committed to halting the loss of biodiversity. However, preserving biodiversity requires knowledge about species distributions. For some species we have good knowledge of distribution and popul...

1. Recovering or threatened carnivore populations are often harvested to minimise their impact on human activities, such as livestock farming or game hunting. Increasingly, harvest quota decisions involve a set of scientific, administrative and political institutions operating at national and sub-national levels whose interactions and collective de...

Eurasian lynx (Lynx lynx) have a wide distribution across Eurasia. The northern edge of this distribution is in Norway, where they reach up to 72 degrees north. We conducted a study of lynx space use in this region from 2007 to 2013 using GPS telemetry. The home range sizes averaged 2,606 (± 438 SE) km2 for males (n = 9 ranges) and 1,456 (± 179 SE)...

Results from biologging studies are often scaled up to population-level inferences and this begs the question: Are instrumented animals representative of the population given the potential bias in individual selectivity, the influence of capture, handling and wearing bio-loggers? The answer is elusive due to the challenges of obtaining comparable d...

Large solitary felids often kill large prey items that can provide multiple meals. However, being able to utilize these multiple meals requires that they can cache the meat in a manner that delays its discovery by vertebrate and invertebrate scavengers. Covering the kill with vegetation and snow is a commonly observed strategy among felids. This st...

Camera trapping, paired with analytical methods for estimating species occurrence, population size or density, can yield information with direct consequences for wildlife management and conservation. Detectability, the ability to detect a species or individual if it is present, affects the reliability and efficiency of camera trap surveys and, in t...

Understanding reproductive physiology of a species is important to assess their potential to respond to environmental variation and perturbation of their social system during the mating or pre-mating seasons. We report 175 parturition dates from wild Eurasian lynx (Lynx lynx) in Scandinavia. Most lynx birth dates were highly synchronised around a m...

Food-caching animals can gain nutritional advantages by buffering seasonality in food availability, especially during times of scarcity. The wolverine (Gulo gulo) is a facultative predator that occupies environments of low productivity. As an adaptation to fluctuating food availability, wolverines cache perishable food in snow, boulders, and bogs f...

Harvesting large carnivores can be a management tool for meeting politically set goals for their desired abundance. However, harvesting carnivores creates its own set of conflicts in both society and among conservation professionals, where one consequence is a need to demonstrate that management is sustainable, evidence‐based, and guided by science...

Rapport om funn av antikoagulerende rodenticider (muse- og rottegifter) i lever fra ulv, gaupe, jerv, rødrev, fjellrev og villmink innsamlet i Norge i perioden 1997-2017

Despite extensive research on the ecology and behavioural adaptations of large carnivores in human-dominated landscapes, information about the fitness consequences of sharing landscapes is still limited. We assessed the variation in three consecutive components of female fitness: the probability of reproduction, litter size and juvenile survival in...

Satellite telemetry is an increasingly utilized technology in wildlife research, and current devices can track individual animal movements at unprecedented spatial and temporal resolutions. However, as we enter the golden age of satellite telemetry, we need an in-depth understanding of the main technological, species-specific and environmental fact...

Tovmo, M., Odden, J., Brøseth, H. & Nilsen, E. B. 2019. Number of family groups, population estimate and population development of lynx in Norway for 2019. NINA Report 1679. Norwegian Institute for Nature Research. Abstract: The national monitoring program for large carnivores follows the Norwegian lynx population primarily through the survey of fa...

Wolf attacks on dogs in Scandinavia.

Tovmo, M., Odden, J., Brøseth, H. & Nilsen, E. B. 2018. Number of family groups, population estimate and population development of lynx in Norway for 2018. - NINA Report 1519. 24 pp. Abstract: The national monitoring program for large carnivores monitors the Norwegian lynx population primarily through the survey of family groups (adult female lynx...

Restrictions on roaming Until the past century or so, the movement of wild animals was relatively unrestricted, and their travels contributed substantially to ecological processes. As humans have increasingly altered natural habitats, natural animal movements have been restricted. Tucker et al. examined GPS locations for more than 50 species. In ge...

Tovmo, M., Odden, J., Brøseth, H. & Nilsen, E. B. 2017. Number of family groups, population estimate and population development of lynx in Norway for 2017. - NINA Report 1370. 24 pp. Abstract: The national monitoring program for large carnivores monitors the Norwegian lynx population primarily through the survey of family groups (adult female lynx...

Migratory prey is a widespread phenomenon that has implications for predator–prey interactions. By creating large temporal variation in resource availability between seasons it becomes challenging for carnivores to secure a regular year-round supply of food. Some predators may respond by following their migratory prey, however, most predators are s...

Sarcoptic mange is a widely distributed disease that affects numerous mammalian species. We used camera traps to investigate the apparent prevalence and spatiotemporal dynamics of sarcoptic mange in a red fox population in southeastern Norway. We monitored red foxes for five years using 305 camera traps distributed across an 18000 km² area. A total...

Dataset. Red fox events detected by camera traps from 2010 until 2015 in the southeast of Norway and covariates used in the study. (XLSX)

What determines whether a predator scavenges or kills its own prey? Using data on wolverines ( Gulo gulo ) in Scandinavia, we studied variation in diet and feeding strategies along a gradient of environmental productivity, seasonality, density, and body mass of their main prey, semidomestic reindeer ( Rangifer tarandus ). Our results suggest that w...

Predator avoidance depends on prey being able to discern how risk varies in space and time, but this is made considerably more complicated if risk is simultaneously present from multiple predators. This is the situation for an increasing number of mammalian prey species, as large carnivores recover or are reintroduced in ecosystems on several conti...

Populations of wide-ranging species are likely to extend across multiple jurisdictions, including national and international borders. This requires that local institutions implement data sharing and a standardization of monitoring designs. However, a formal evaluation of the benefits of integrated monitoring systems had not, of yet, been performed....

Appendix S1. The use of yearly roe deer hunting bags as proxy for roe deer density. Figure S1. Proportion of 90% isopleth area included in the 50% isopleth for male in relation to prey density index. Table S1. Model selection relating lynx annual home range size to (a) the interaction between country and prey density index and (b) the interaction...

Home range (HR) size variation is often linked to resource abundance, with sex differences expected to relate to sex-specific fitness consequences. However, studies generally fail to disentangle the effects of the two main drivers of HR size variation, food and conspecific density, and rarely consider how their relative influence change over spatio...

Predator efficiency depends on how hunting tactics relate to habitat characteristics. Different tactics such as ambush, stalking, and pursuit may lead to spatially heterogeneous distributions of predation risk. Studying how such a landscape of risk looks in a multi-predator setting has become topical in light of the re-colonization of apex predator...

In carnivores, securing suitable den sites with associated early maternal home ranges is important for successful reproduction, and understanding natal den site selection is essential to ensure that these habitats are protected from human disturbance. This study investigated Eurasian lynx Lynx lynx natal den site selection across multiple use lands...

In Norway, recovering populations of large carnivores commonly prey on roe deer (Capreolus capreolus). Understanding predator habitat use and ecology requires fine-scaled information on prey distribution and abundance. However, the massive spatial scales at which large carnivores use the landscape presents many practical and statistical challenges...

Shape files of current and historical distribution maps of large carnivore species in Europe. Also available from http://datadryad.org/resource/doi:10.5061/dryad.986mp

The conservation of large carnivores is a formidable challenge for biodiversity conservation. Using a data set on the past and current status of brown bears (Ursus arctos), Eurasian lynx (Lynx lynx), gray wolves (Canis lupus), and wolverines (Gulo gulo) in European countries, we show that roughly one-third of mainland Europe hosts at least one larg...

The activity patterns of most terrestrial animals are regarded as being primarily influenced by light, although other factors, such as sexual cycle and climatic conditions, can modify the underlying patterns. However, most activity studies have been limited to a single study area, which in turn limit the variability of light conditions and other fa...

Conserving large carnivores in multi-use landscape is a global challenge. In northern Norway the presence of Eurasian lynx (Lynx lynx) conflicts greatly with the current ways of keeping free-grazing, unguarded livestock in large carnivore habitat. In contrast to most other places in Europe, livestock (sheep Ovis aries, reindeer Rangifer tarandus) a...

The relative merits of land sparing versus land sharing are being debated within conservation biology. While the debate is multifaceted, a central issue concerns the ability of biodiversity to actually persist in ‘shared’ human-dominated landscapes. There is a widespread perception that large predators are synonymous with wilderness and have a low...

The theory of predation risk effects predicts behavioral responses in prey when risk of predation is not homogenous in space and time. Prey species are often faced with a tradeoff between food and safety in situations where food availability and predation risk peak in the same habitat type. Determining the optimal strategy becomes more complex if p...

Felids generally follow a poly-estrous reproductive strategy. Eurasian lynx (Lynx lynx) display a different pattern of reproductive cyclicity where physiologically persistent corpora lutea (CLs) induce a mono-estrous condition which results in highly seasonal reproduction. The present study was based around a sono-morphological and endocrine study...

Depredation on livestock and competition with hunters for game species are prominent among the conflicts that the return of large carnivores generates in multi-use landscapes. The relative magnitude of the conflict strongly depends on what prey selection patterns predators will adopt once established in a new area. We explored prey selection and ki...

Understanding the factors shaping the dynamics of carnivore-livestock conflicts is vital to facilitate large carnivore conservation in multi-use landscapes. We investigated how the density of their main wild prey, roe deer Capreolus capreolus, modulates individual Eurasian lynx Lynx lynx kill rates on free-ranging domestic sheep Ovis aries across a...

The Eurasian lynx is an efficient stalking predator mainly selecting small-sized ungulates. In northern Scandinavia, semi-domestic reindeer are the only ungulate species available for Eurasian lynx year round and consequently constitute their main prey. Selective predation patterns by a predator on a domestic prey are likely to be influenced by hus...

Mortality rates and patterns are fundamental demographic traits for understanding the dynamics of populations of large herbivores in different environments. Despite the ongoing recovery of large carnivores in Europe and North America, few European studies on ungulate mortality are available from areas where both large carnivores and human hunters a...

Lack proposed that the average clutch size of altricial species should be determined by the average maximum number of young the parents can raise such that all females in a given population should share a common optimal clutch size. Support for this model remains equivocal and recent studies have suggested that intra‐population variation in clutch...

Habitat selection studies generally assume that animals select habitat and food resources at multiple scales to maximise their fitness. However, animals sometimes prefer habitats of apparently low quality, especially when considering the costs associated with spatially heterogeneous human disturbance. We used spatial variation in human disturbance,...

There is a political goal that the Norwegian wolverine population should primarily be regulated through ordinary license hunt as opposed to damage control conducted by the authorities. However, hunting of wolverines has proven to be demanding. In several of the management zones the quota is far from reached by local license hunt. In this report we...

Abstract Gervasi, V., Odden, J., Linnell, J.D.C., Persson, J., Andrén, H. & Brøseth, H. 2013. Reevaluation of distance criteria for classification of lynx family groups in Scandinavia. – NINA Report 965. 32 pp. Monitoring of lynx populations in Scandinavia have largely been based around unreplicated minimum counts of family groups. Observations are...

Predator selectivity for age and sex classes has large implications for their impact on prey populations. We examined whether the Eurasian lynx Lynx lynx selects specific sex and age categories of roe deer Capreolus capreolus, and if this selection pattern differs between summer and winter. Data on sex and age of 194 roe deer killed by 44 VHF-and G...

Winter climate at northern latitudes is a challenge to small-bodied ungulates, and they modify behaviour to save energy and to increase the likelihood of survival. Also, the ongoing expansion of large carnivores in several European countries can lead to the recovery of (potentially energetically costly) anti-predator behaviours. In an area recently...

Large carnivores (bears Ursus arctos, wolves Canis lupus, lynx Lynx lynx and wolverines Gulo gulo) are among the most challenging group of species to maintain as large and continuous populations or to reintegrate back into the European landscape. Political, socioeconomic and society changes challenge past management approaches in some of the large...

Understanding the drivers of seasonal migration among large herbivores is crucial for management and conservation. The forage maturation hypothesis predicts migration even at low population density, due to the benefits of increased access to newly emergent, high quality forage. We provide the first study comparing migration tendency of the two most...

Detailed knowledge of the variation in demographic rates is central for our ability to understand the evolution of life history strategies and population dynamics, and to plan for the conservation of endangered species. We studied variation in reproductive output of 61 radio-collared Eurasian lynx females in four Scandinavian study sites spanning a...

Harvesting large carnivores is often a controversial issue and thus requires a higher precision than other types of recreational harvest. Despite this, management programmes are often initiated based on very limited knowledge about the state of the population and the composition and magnitude of the harvest. Here we analyse patterns of lynx harvest...