Barbara Zimmermann

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Network structure of vertebrate scavenger assemblages at the global scale: drivers and ecosystem functioning implications

Esther Sebastián‐González, Zebensui Morales‐Reyes, Francisco Botella, Lara Naves‐Alegre, more

Ecography > 43 > 8 > 1143 - 1155

The organization of ecological assemblages has important implications for ecosystem functioning, but little is known about how scavenger communities organize at the global scale. Here, we test four hypotheses on the factors affecting the network structure of terrestrial vertebrate scavenger assemblages and its implications on ecosystem functioning. We expect scavenger assemblages to be more nested...

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Scavenging in the Anthropocene: Human impact drives vertebrate scavenger species richness at a global scale

Esther Sebastián‐González, Jomar Magalhães Barbosa, Juan M. Pérez‐García, Zebensui Morales‐Reyes, more

Global Change Biology > 25 > 9 > 3005 - 3017

Understanding the distribution of biodiversity across the Earth is one of the most challenging questions in biology. Much research has been directed at explaining the species latitudinal pattern showing that communities are richer in tropical areas; however, despite decades of research, a general consensus has not yet emerged. In addition, global biodiversity patterns are being rapidly altered by...

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Integrated spatially-explicit models predict pervasive risks to recolonizing wolves in Scandinavia from human-driven mortality

Mariano R. Recio, Barbara Zimmermann, Camilla Wikenros, Andreas Zetterberg, more

Biological Conservation > 2018 > 226 > C > 111-119

Human-driven wildlife mortality is caused by both indirect causes and direct persecution due to conflicts of interests. The wolf, a predator frequently at risk from human-wildlife conflict, is returning to areas where it was historically extirpated in Scandinavia (Sweden and Norway). The wolf is expanding via a management strategy that allows wolves to reproduce exclusively in a wolf breeding range...

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Spatial mismatch between management units and movement ecology of a partially migratory ungulate

Erling L. Meisingset, Leif E. Loe, Øystein Brekkum, Richard Bischof, more

Journal of Applied Ecology > 55 > 2 > 745 - 753

Population‐level management is difficult to achieve if wildlife routinely crosses administrative boundaries, as is particularly frequent for migratory populations. However, the degree of mismatch between management units and scales at which ecological processes operate has rarely been quantified. Such insight is vital for delimiting functional population units of partially migratory species common...

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Estimating wolf (Canis lupus) population size from number of packs and an individual based model

Guillaume Chapron, Camilla Wikenros, Olof Liberg, Petter Wabakken, more

Ecological Modelling > 2016 > 339 > C > 33-44

Estimating wildlife population size is fundamental for wildlife management and conservation. However, making monitoring of population size less resource demanding while still keeping a high monitoring accuracy and precision remains a recurrent challenge. One proposed alternative to count individuals is to instead focus on counting a segment of the population that is easier to monitor but at the same...

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Sarcoptic mange in the Scandinavian wolf Canis lupus population

Boris Fuchs, Barbara Zimmermann, Petter Wabakken, Set Bornstein, more

BMC Veterinary Research > 2016 > 12 > 1 > 1-12

Background Sarcoptic mange, a parasitic disease caused by the mite Sarcoptes scabiei, is regularly reported on wolves Canis lupus in Scandinavia. We describe the distribution and transmission of this parasite within the small but recovering wolf population by analysing 269 necropsy reports and performing a serological survey on 198 serum samples collected from free-ranging wolves between 1998 and...

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High infection intensities, but negligible fitness costs, suggest tolerance of gastrointestinal nematodes in a tropical snake

Martin Mayer, Gregory P. Brown, Barbara Zimmermann, Richard Shine

Austral Ecology > 40 > 6 > 683 - 692

We investigated patterns of prevalence and intensity of gastrointestinal nematode infections in a tropical natricine snake, the keelback (Tropidonophis mairii). Ninety‐eight per cent of keelbacks were infected with Tanqua anomala (Gnathostomidae), with infection intensities of up to 243 worms per snake. Infection with T. anomala caused severe inflammation of stomach mucosa and submucosa at the sites...

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Predator‐dependent functional response in wolves: from food limitation to surplus killing

Barbara Zimmermann, Håkan Sand, Petter Wabakken, Olof Liberg, more

Journal of Animal Ecology > 84 > 1 > 102 - 112

The functional response of a predator describes the change in per capita kill rate to changes in prey density. This response can be influenced by predator densities, giving a predator‐dependent functional response. In social carnivores which defend a territory, kill rates also depend on the individual energetic requirements of group members and their contribution to the kill rate.This study aims to...

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Assessing the influence of prey–predator ratio, prey age structure and packs size on wolf kill rates

Håkan Sand, John A. Vucetich, Barbara Zimmermann, Petter Wabakken, more

Oikos > 121 > 9 > 1454 - 1463

Traditional predation theory assumes that prey density is the primary determinant of kill rate. More recently, the ratio of prey‐to‐predator has been shown to be a better predictor of kill rate. However, the selective behavior of many predators also suggests that age structure of the prey population should be an important predictor of kill rate. We compared wolf–moose predation dynamics in two sites,...

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Predicting the potential demographic impact of predators on their prey: a comparative analysis of two carnivore–ungulate systems in Scandinavia

Vincenzo Gervasi, Erlend B. Nilsen, Håkan Sand, Manuela Panzacchi, more

Journal of Animal Ecology > 81 > 2 > 443 - 454

1. Understanding the role of predation in shaping the dynamics of animal communities is a fundamental issue in ecological research. Nevertheless, the complex nature of predator–prey interactions often prevents researchers from modelling them explicitly. 2. By using periodic Leslie–Usher matrices and a simulation approach together with parameters obtained from long‐term field projects, we reconstructed...

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Partial migration in expanding red deer populations at northern latitudes – a role for density dependence?

Atle Mysterud, Leif Egil Loe, Barbara Zimmermann, Richard Bischof, more

Oikos > 120 > 12 > 1817 - 1825

Partial migration is common in ungulates living in highly seasonal environments. Typically, at higher latitudes, this involves movement between high elevation summer areas used during breeding and lowland areas with less snow used during winter. Snow depth is regarded the main cause of migration to low elevation, but it is less clear why deer migrate to high elevation in spring. The forage maturation...

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Activity patterns of predator and prey: a simultaneous study of GPS-collared wolves and moose

Ane Eriksen, Petter Wabakken, Barbara Zimmermann, Harry P. Andreassen, more

Animal Behaviour > 2011 > 81 > 2 > 423-431

We studied the simultaneous activity patterns of a breeding wolf, Canis lupus, pair and five adult moose, Alces alces, cows from April to November 2004 in a wolf territory in southeastern Norway. All study animals were GPS collared, and we used a total of 8297 fixes to analyse their temporal activity patterns. We examined the daily activity rhythm of the two species and how this varied seasonally...

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Guanine Nucleotide-Binding Proteins of the G12 Family Shape Immune Functions by Controlling CD4+ T Cell Adhesiveness and Motility

Susanne Herroeder, Peter Reichardt, Antonia Sassmann, Barbara Zimmermann, more

Immunity > 2009 > 30 > 5 > 708-720

Integrin-mediated adhesion plays a central role in T cell trafficking and activation. Genetic inactivation of the guanine nucleotide-binding (G) protein α-subunits Gα ₁₂ and Gα ₁₃ resulted in an increased activity of integrin leukocyte-function-antigen-1 in murine CD4 ⁺ T cells. The interaction with allogeneic dendritic cells was enhanced, leading to an abnormal proliferative...

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Encounter frequencies between GPS-collared wolves (Canis lupus) and moose (Alces alces) in a Scandinavian wolf territory

Ane Eriksen, Petter Wabakken, Barbara Zimmermann, Harry P. Andreassen, more

Ecological Research > 2009 > 24 > 3 > 547-557

Over 6,000 GPS fixes from two wolves (Canis lupus) and 30,000 GPS fixes from five moose (Alces alces) in a wolf territory in southern Scandinavia were used to assess the static and dynamic interactions between predator and prey individuals. Our results showed that wolves were closer to some of the moose when inside their home ranges than expected if they had moved independently of each other, and...

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Summer kill rates and predation pattern in a wolf–moose system: can we rely on winter estimates?

Håkan Sand, Petter Wabakken, Barbara Zimmermann, Örjan Johansson, more

Oecologia > 2008 > 156 > 1 > 53-64

So far the vast majority of studies on large carnivore predation, including kill rates and consumption, have been based on winter studies. Because large carnivores relying on ungulates as prey often show a preference for juveniles, kill rates may be both higher and more variable during the summer season than during the rest of the year leading to serious underestimates of the total annual predation...

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Three approaches to estimate wolf Canis lupus predation rates on moose Alces alces populations

Hege Gundersen, Erling J. Solberg, Petter Wabakken, Torstein Storaas, more

European Journal of Wildlife Research > 2008 > 54 > 2 > 335-346

We employed three different methods to estimate predation rates on moose in a newly colonized wolf territory in Norway. In the first two methods, we estimated predation rates based on the difference in calf/cow ratios outside and inside the wolf pack territory from (1) hunter observations and (2) aerial surveys. In the last method, (3) we estimated loss of calves of radio-collared cows inside and...

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Differentiation and levels of genetic variation in northern European lynx (Lynx lynx) populations revealed by microsatellites and mitochondrial DNA analysis

Linda Hellborg, Christopher W. Walker, Eli Knispel Rueness, John E. Stacy, more

Conservation Genetics > 2002 > 3 > 2 > 97-111

The European lynx (Lynx lynx) hasexperienced significant decline in populationnumbers over large parts of its formerdistribution area in central and northernEurope. In Scandinavia (Sweden and Norway), thespecies has been subject to intense hunting and inthe early 20th century the population size mayhave been as low as about 100 animals. Duringthe rest of the century there have beenalternating periods...

INFONA - science communication portal

Search results for: Barbara Zimmermann

Network structure of vertebrate scavenger assemblages at the global scale: drivers and ecosystem functioning implications

Scavenging in the Anthropocene: Human impact drives vertebrate scavenger species richness at a global scale

Integrated spatially-explicit models predict pervasive risks to recolonizing wolves in Scandinavia from human-driven mortality

Spatial mismatch between management units and movement ecology of a partially migratory ungulate

Estimating wolf (Canis lupus) population size from number of packs and an individual based model

Sarcoptic mange in the Scandinavian wolf Canis lupus population

High infection intensities, but negligible fitness costs, suggest tolerance of gastrointestinal nematodes in a tropical snake

Predator‐dependent functional response in wolves: from food limitation to surplus killing

Assessing the influence of prey–predator ratio, prey age structure and packs size on wolf kill rates

Predicting the potential demographic impact of predators on their prey: a comparative analysis of two carnivore–ungulate systems in Scandinavia

Partial migration in expanding red deer populations at northern latitudes – a role for density dependence?

Activity patterns of predator and prey: a simultaneous study of GPS-collared wolves and moose

Guanine Nucleotide-Binding Proteins of the G12 Family Shape Immune Functions by Controlling CD4+ T Cell Adhesiveness and Motility

Encounter frequencies between GPS-collared wolves (Canis lupus) and moose (Alces alces) in a Scandinavian wolf territory

Summer kill rates and predation pattern in a wolf–moose system: can we rely on winter estimates?

Three approaches to estimate wolf Canis lupus predation rates on moose Alces alces populations

Differentiation and levels of genetic variation in northern European lynx (Lynx lynx) populations revealed by microsatellites and mitochondrial DNA analysis

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