Svenja B. Kroeger

Research Scientist

(+47) 908 21 036
svenja.kroeger@nibio.no

Place
Trondheim

Visiting address
Klæbuveien 153, bygg C 1.etasje, 7031 Trondheim

Biography

Evolutionary ecologist with a background in life-history evolution and senescence. My research focus is on understanding impacts of environmental variation, including anthropogenic disturbance, such as infrastructure development, on animal populations and biodiversity in general. I have worked with a range of study systems including insects, plants, mammals and birds, and my particular expertise lies with sciurids.

Degrees:

Ph.D. in Ecology at the University of Aberdeen (2017)

B.Sc. (Hons) in Animal Biology at the University of Stirling (2013)

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Abstract

Studies in natural populations are essential to understand the evolutionary ecology of senescence and terminal allocation. While there are an increasing number of studies investigating late-life variation in different life-history traits of wild populations, little is known about these patterns in social behaviour. We used long-term individual based data on yellow-bellied marmots (Marmota flaviventer) to quantify how affiliative social behaviours and different life-history traits vary with age and in the last year of life, and how patterns compare between the two. We found that some social behaviours and all life-history traits varied with age, whereas terminal last year of life effects were only observed in life-history traits. Our results imply that affiliative social behaviours do not act as a mechanism to adjust allocation among traits when close to death, and highlight the importance of adopting an integrative approach, studying late-life variation and senescence across multiple different traits, to allow the identification of potential trade-offs. This article is part of the theme issue ‘Ageing and sociality: why, when and how does sociality change ageing patterns?’

Abstract

The diversity and abundance of pollinating insects is declining on a global scale and urgent action is needed. This is a brief film about the importance of pollinators, what is being done in Norway to counteract pollinator decline, and how you can help. Together, we can make a difference.

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Abstract

Roadsides, in particular those being species-rich and of conservation value, are considered to improve landscape permeability by providing corridors among habitat patches and by facilitating species' dispersal. However, little is known about the potential connectivity offered by such high-value roadsides. Using circuit theory, we modelled connectivity provided by high-value roadsides in landscapes with low or high permeability in south-central Sweden, with ‘permeability’ being measured by the area of semi-natural grasslands. We modelled structural connectivity and, for habitat generalists and specialists, potential functional connectivity focusing on butterflies. We further assessed in which landscapes grassland connectivity is best enhanced through measures for expanding the area of high-value roadsides. Structural connectivity provided by high-value roadsides resulted in similar patterns to those of a functional approach, in which we modelled habitat generalists. In landscapes with low permeability, all target species showed higher movements within compared to between grasslands using high-value roadsides. In landscapes with high permeability, grassland generalists and specialists showed the same patterns, whereas for habitat generalists, connectivity provided by high-value roadsides and grasslands was similar. Increasing the ratio of high-value roadsides can thus enhance structural and functional connectivity in landscapes with low permeability. In contrast, in landscapes with high permeability, roadsides only supported movement of specialised species. Continuous segments of high-value roadsides are most efficient to increase connectivity for specialists, whereas generalists can utilize also short segments of high-value roadsides acting as stepping-stones. Thus, land management should focus on the preservation and restoration of existing semi-natural grasslands. Management for enhancing grassland connectivity through high-value roadsides should aim at maintaining and creating high-value roadside vegetation, preferably in long continuous segments, especially in landscapes with low permeability.

To document

Abstract

Studies in natural populations are essential to understand the evolutionary ecology of senescence and terminal allocation. While there are an increasing number of studies investigating late-life variation in different life-history traits of wild populations, little is known about these patterns in social behaviour. We used long-term individual based data on yellow-bellied marmots (Marmota flaviventer) to quantify how affiliative social behaviours and different life-history traits vary with age and in the last year of life, and how patterns compare between the two. We found that some social behaviours and all life-history traits varied with age, whereas terminal last year of life effects were only observed in life-history traits. Our results imply that affiliative social behaviours do not act as a mechanism to adjust allocation among traits when close to death, and highlight the importance of adopting an integrative approach, studying late-life variation and senescence across multiple different traits, to allow the identification of potential trade-offs. This article is part of the theme issue ‘Ageing and sociality: why, when and how does sociality change ageing patterns?’

To document

Abstract

Roadsides can harbour remarkable biodiversity; thus, they are increasingly considered as habitats with potential for conservation value. To improve construction and management of roadside habitats with positive effects on biodiversity, we require a quantitative understanding of important influential factors that drive both positive and negative effects of roads. We conducted meta-analyses to assess road effects on bird communities. We specifically tested how the relationship between roads and bird richness varies when considering road type, habitat characteristics and feeding guild association. Overall, bird richness was similar in road habitats compared to non-road habitats, however, the two apparently differ in species composition. Bird richness was lowered by road presence in areas with denser tree cover but did not differ according to road type. Richness differences between habitats with and without roads further depended on primary diet of species, and richness of omnivores was positively affected by road presence. We conclude that impacts of roads on bird richness are highly context-dependent, and planners should carefully evaluate road habitats on a case by case basis. This emphasizes the need for further studies that explicitly test for differences in species composition and abundance, to disentangle contexts where a road will negatively affect bird communities, and where it will not.