As one of the few large predators in Scandinavia, ecological research of wolverines that facilitates science-based management and conservation is crucial. Wolverines cause losses for Sámi reindeer husbandry. This means management authorities have to compromise between goals to maintain both a sustainable reindeer husbandry and a viable wolverine population. Thus, there is an immediate need for more knowledge to manage this situation.
This project is a long-term individual-based study on wolverine ecology, which provide a unique opportunity to investigate population dynamics, life history and behavioral ecology of wolverines. We use this opportunity to answer general ecological questions that are also needed for management of carnivore conflicts in general, and in the reindeer husbandry area in particular.
Currently, our project focuses on the following themes:
• Habitat ecology and demography - mechanisms explaining spatial variation in the density of these populations.
• Population dynamics and consequences of management actions
• Interactions between lynx and wolverine, and their predation on reindeer.
• Spatial and social ecology.
• Denning ecology of wolverine females; aspects that are relevant for validation and development of methods for wolverine population surveys.
This project is a long-term individual-based study on wolverine ecology, which provide a unique opportunity to investigate population dynamics, life history and behavioral ecology of wolverines. We use this opportunity to answer general ecological questions that are also needed for management of carnivore conflicts in general, and in the reindeer husbandry area in particular.
Currently, our project focuses on the following themes:
• Habitat ecology and demography - mechanisms explaining spatial variation in the density of these populations.
• Population dynamics and consequences of management actions
• Interactions between lynx and wolverine, and their predation on reindeer.
• Spatial and social ecology.
• Denning ecology of wolverine females; aspects that are relevant for validation and development of methods for wolverine population surveys.
For results from our previous research visit our wolverine ecology pages.
Current research themes
Habitat ecology and demography; mechanisms explaining spatial variation in population density
Aim: To identify linkages between demographic performance and environmental factors, from individual fitness to population level. To gain full insight into the functioning of populations in space and time requires merging analyses of demography and habitat selection. We will use the lynx and wolverine as model species to implement theories linking demography to habitat and other factors. We will thereby provide ecological knowledge of what factors determine population density in different areas and identify demographic suitability of different habitats. In contrast to management goals, both lynx and wolverine populations show patchy distribution in Sweden. Thus, knowledge that reveal mechanisms behind that pattern will enable managers to better implement plans to fulfil goals to sustain viable populations and minimize conflicts. Main research questions within this theme are:
• How do individual lynx and wolverine reproductive success vary with environmental factors (e.g. prey base)?
• How is individual lynx and wolverine survival affected by habitat and other factors (e.g. human activity)?
• How is demographic performance at population level affected by habitat and other factors, as revealed by annual presence of lynx/wolverine
reproductions in relation to habitat and anthropogenic covariates?
• What are the characteristics of source, sink and attractive sink habitats?
Population dynamics and consequences of management actions
Aim: To explore and quantify why population growth rate varies in time, and to investigate the effects of different management actions on population performance and viability. An integral part of our research is to understand the influence of intrinsic (age, sex, etc.) and external factors (e.g. food, harvest) on lynx and wolverine demographic parameters and their variation. Because of its fundamental importance for our ability to understand effects of management actions, we will continue our effort towards a deeper understanding of lynx and wolverine population dynamics.
Main research questions within this theme are:
• How do population size and different management actions (e.g. harvest) and strategies (e.g.management unit size) influence population viability
and what is a sustainable harvest strategy?
• How do different life histories of two carnivores translate into effects of management actions on performance of the two populations,respectively?
• To what extent is legal harvest additive or compensatory to illegal harvest?
The interaction between lynx and wolverine, and their predation on reindeer
Aim: To quantify and understand the mechanisms determining individual kill rates and to model the impact of predation on reindeer herding industry. To understand spatial and temporal interactions between two carnivores and its influence on both species foraging ecology and demography, and the effect on the prey population. Lynx predation upon reindeer varies considerably in time and among individuals. Preliminary analyses suggest that the lynx is a more efficient predator than the wolverine. Knowledge of both the mean and the variation in kill rate, and its determinants, is important for the compensation scheme for predator-killed reindeer. The mean provides guidance about the compensation level, whereas the variation provides guidance on how static this process is and thus the fairness of the compensation scheme. The compensation assumes a constant relationship between predator numbers and losses of reindeer. However, if there is large individual variation in kill rate, this assumption does not hold. Furthermore, preliminary data suggest that wolverines to a large extent scavenge reindeer killed by lynx, and we have demonstrated that wolverine reproduction is influenced by carcass availability in winter (Persson 2005). Consequently, interspecific interactions could exert strong influence on both wolverine demography and total predation upon reindeer. Main research questions within this theme are:
• What mechanisms explain why kill rate varies between individuals and areas?
• What is the spatial and temporal relationship between wolverine and lynx with respect to home range positioning, movements and habitat selection?
• How do lynx-wolverine interactions influence wolverine food availability and demography, as well as the total predation pressure on the reindeer population?
Spatial and social ecology
Aim: To understand wolverine spatial and social ecology and the mechanisms for its reciprocal effect on/of harvest. Spatial and social ecology are important aspects in understanding the ecology of animals due to its influence on population structure and dynamics. For example, dispersal and behavioural adjustment of territory size have important consequences for demography and population regulation. Hence, we will combine demographic studies with those on territoriality, mating system and dispersal to improve our understanding of population dynamics and effects of harvest. Main research questions within this theme are:
• Are wolverine populations regulated by a land-tenure system? To what extent do different mechanisms (e.g. harvest, relatedness) explain
territorial dynamics?
• What factors influence dispersal distance and establishment? What is the spatial and temporal distribution of dispersers in relation to e.g.
reindeer migration?
• What mechanism explains the occurrence of infanticide in wolverines?
• What are the relationship between dispersal pattern and female survival and reproduction, and does it result in maternal clusters?
Habitat ecology and demography; mechanisms explaining spatial variation in population density
Aim: To identify linkages between demographic performance and environmental factors, from individual fitness to population level. To gain full insight into the functioning of populations in space and time requires merging analyses of demography and habitat selection. We will use the lynx and wolverine as model species to implement theories linking demography to habitat and other factors. We will thereby provide ecological knowledge of what factors determine population density in different areas and identify demographic suitability of different habitats. In contrast to management goals, both lynx and wolverine populations show patchy distribution in Sweden. Thus, knowledge that reveal mechanisms behind that pattern will enable managers to better implement plans to fulfil goals to sustain viable populations and minimize conflicts. Main research questions within this theme are:
• How do individual lynx and wolverine reproductive success vary with environmental factors (e.g. prey base)?
• How is individual lynx and wolverine survival affected by habitat and other factors (e.g. human activity)?
• How is demographic performance at population level affected by habitat and other factors, as revealed by annual presence of lynx/wolverine
reproductions in relation to habitat and anthropogenic covariates?
• What are the characteristics of source, sink and attractive sink habitats?
Population dynamics and consequences of management actions
Aim: To explore and quantify why population growth rate varies in time, and to investigate the effects of different management actions on population performance and viability. An integral part of our research is to understand the influence of intrinsic (age, sex, etc.) and external factors (e.g. food, harvest) on lynx and wolverine demographic parameters and their variation. Because of its fundamental importance for our ability to understand effects of management actions, we will continue our effort towards a deeper understanding of lynx and wolverine population dynamics.
Main research questions within this theme are:
• How do population size and different management actions (e.g. harvest) and strategies (e.g.management unit size) influence population viability
and what is a sustainable harvest strategy?
• How do different life histories of two carnivores translate into effects of management actions on performance of the two populations,respectively?
• To what extent is legal harvest additive or compensatory to illegal harvest?
The interaction between lynx and wolverine, and their predation on reindeer
Aim: To quantify and understand the mechanisms determining individual kill rates and to model the impact of predation on reindeer herding industry. To understand spatial and temporal interactions between two carnivores and its influence on both species foraging ecology and demography, and the effect on the prey population. Lynx predation upon reindeer varies considerably in time and among individuals. Preliminary analyses suggest that the lynx is a more efficient predator than the wolverine. Knowledge of both the mean and the variation in kill rate, and its determinants, is important for the compensation scheme for predator-killed reindeer. The mean provides guidance about the compensation level, whereas the variation provides guidance on how static this process is and thus the fairness of the compensation scheme. The compensation assumes a constant relationship between predator numbers and losses of reindeer. However, if there is large individual variation in kill rate, this assumption does not hold. Furthermore, preliminary data suggest that wolverines to a large extent scavenge reindeer killed by lynx, and we have demonstrated that wolverine reproduction is influenced by carcass availability in winter (Persson 2005). Consequently, interspecific interactions could exert strong influence on both wolverine demography and total predation upon reindeer. Main research questions within this theme are:
• What mechanisms explain why kill rate varies between individuals and areas?
• What is the spatial and temporal relationship between wolverine and lynx with respect to home range positioning, movements and habitat selection?
• How do lynx-wolverine interactions influence wolverine food availability and demography, as well as the total predation pressure on the reindeer population?
Spatial and social ecology
Aim: To understand wolverine spatial and social ecology and the mechanisms for its reciprocal effect on/of harvest. Spatial and social ecology are important aspects in understanding the ecology of animals due to its influence on population structure and dynamics. For example, dispersal and behavioural adjustment of territory size have important consequences for demography and population regulation. Hence, we will combine demographic studies with those on territoriality, mating system and dispersal to improve our understanding of population dynamics and effects of harvest. Main research questions within this theme are:
• Are wolverine populations regulated by a land-tenure system? To what extent do different mechanisms (e.g. harvest, relatedness) explain
territorial dynamics?
• What factors influence dispersal distance and establishment? What is the spatial and temporal distribution of dispersers in relation to e.g.
reindeer migration?
• What mechanism explains the occurrence of infanticide in wolverines?
• What are the relationship between dispersal pattern and female survival and reproduction, and does it result in maternal clusters?
