| 1. |
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| 2. |
- Andrén, Henrik, et al.
(author)
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Harvest models of small populations of a large carnivore using Bayesian forecasting
- 2020
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In: Ecological Applications. - : Wiley. - 1051-0761 .- 1939-5582. ; 30:3
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Journal article (peer-reviewed)abstract
- 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. Furthermore, because large carnivores often also have high degrees of legal protection, harvest quotas have to be carefully justified and constantly adjusted to avoid damaging their conservation status. We developed a Bayesian state-space model to support adaptive management of Eurasian lynx harvesting in Scandinavia. The model uses data from the annual monitoring of lynx abundance and results from long-term field research on lynx biology, which has provided detailed estimates of key demographic parameters. We used the model to predict the probability that the forecasted population size will be below or above the management objectives when subjected to different harvest quotas. The model presented here informs decision makers about the policy risks of alternative harvest levels. Earlier versions of the model have been available for wildlife managers in both Sweden and Norway to guide lynx harvest quotas and the model predictions showed good agreement with observations. We combined monitoring data with data on vital rates and were able to estimate unobserved additional mortality rates, which are most probably due to poaching. In both countries, the past quota setting strategy suggests that there has been a de facto threshold strategy with increasing proportion, which means that there is no harvest below a certain population size, but above this threshold there is an increasing proportion of the population harvested as the population size increases. The annual assessment of the monitoring results, the use of forecasting models, and a threshold harvest approach to quota setting will all reduce the risk of lynx population sizes moving outside the desired goals. The approach we illustrate could be adapted to other populations of mammals worldwide.
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| 3. |
- Augustsson, Evelina, et al.
(author)
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Density-dependent dinner: Wild boar overuse agricultural land at high densities
- 2024
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In: European Journal of Wildlife Research. - 1612-4642 .- 1439-0574. ; 70
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Journal article (peer-reviewed)abstract
- The Swedish wild boar (Sus scrofa) population has increased rapidly over the last decades, resulting in conflicts with human activities. Particularly, the increase has been challenging for agriculture as wild boar cause damage on crops and grasslands. To predict under what conditions to expect damage and where to prioritize management actions, basic knowledge about wild boar habitat and space use is needed. In this study, we used data from 99 wild boar equipped with GPS-collars, collected over a large temporal scale and throughout their distributional range in southern Sweden. We investigated wild boar home range size and habitat use across gradients of habitat availability and population density. Functional response in habitat use was assessed by estimating the use and availability of agricultural land on individual level and then, on population-level evaluating how use changed with changing availability. Finally, a potential response in habitat use was evaluated in relation to population density, i.e., the interaction between availability and population density. Home range size was negatively related to population density for both male and female wild boar. Wild boar used agricultural land more intensively with increasing population density and when other habitat types were less available. Our findings show that wild boar spatial behavior is highly context dependent and may vary considerably due to landscape characteristics and local conditions. Wild boars tend to overuse agricultural land at high densities which has strong implications for wildlife management. It is therefore important to consider local conditions when predicting space and habitat use by wild boar. Overall, this study provided a better understanding of the drivers of wild boar distribution and space use in agro-forested mosaic landscapes and how this knowledge can improve management practices.
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| 4. |
- Månsson, Johan, et al.
(author)
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Quantitative estimates of tree species selectivity by moose (Alces alces) in a forest landscape
- 2007
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In: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 22:5, s. 407-414
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Journal article (peer-reviewed)abstract
- An extensive literature is available on browsing preference for certain tree species. However, useful predictive tools for estimating the impact of deer on forests production and biodiversity can still be improved. A step in that direction is not only to rank preference among tree species but also to quantify the relative risk of being browsed. The foraging selectivity of moose was evaluated using three different statistical methods developed to study habitat utilization. The general pattern for the three methods was consistent. From the results, groups of forage species were clustered and a quantitative index of selectivity was calculated for the groups. The selectivity index showed that rowan (Sorbus aucuparia), willow (Salix ssp.) and aspen (Populus tremula) had a 14 times higher probability of being browsed than a group consisting of Scots pine (Pinus sylvestris) and downy birch (Betula pubescens), while juniper (Juniperus communis) and silver birch (Betula pendula) had a 3.5 times higher probability than Scots pine and downy birch. Since the most preferred species were the least abundant, one should be cautious about the generality of the index between areas, as it may indicate that preference depends on plant species composition. The method used can easily be applied in forest management. Information on quantitative selectivity indices may improve the possibility of managing moose in accordance with acceptable browsing damage.
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| 5. |
- Watanabe, Hiroyuki, et al.
(author)
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Asymmetry of the Endogenous Opioid System in the Human Anterior Cingulate : a Putative Molecular Basis for Lateralization of Emotions and Pain
- 2015
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In: Cerebral Cortex. - United kingdom : Oxford University Press (OUP). - 1047-3211 .- 1460-2199. ; 25:1, s. 97-108
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Journal article (peer-reviewed)abstract
- Lateralization of processing of positive and negative emotions and pain suggests an asymmetric distribution of the neurotransmitter systems regulating these functions between the left and right brain hemispheres. By virtue of their ability to selectively mediate euphoria, dysphoria and pain, the m-, d- and k-opioid receptors and their endogenous ligands may subserve these lateralized functions. We addressed this hypothesis by comparing the levels of the opioid receptors and peptides in the left and right anterior cingulate cortex (ACC), a key area for emotion and pain processing. Opioid mRNAs and peptides and five “classical” neurotransmitters were analyzed in postmortem tissues from 20 human subjects. Leu-enkephalin-Arg and Met-enkephalin-Arg-Phe, preferential d-/m- and k-/m-opioid agonists demonstrated marked lateralization to the left and right ACC, respectively. Dynorphin B strongly correlated with Leu-enkephalin-Arg in the left but not right ACC suggesting different mechanisms of conversion of this k-opioid agonist to d-/m-opioid ligand in the two hemispheres; in the right ACC dynorphin B may be cleaved by PACE4, a proprotein convertase regulating left-right asymmetry formation. These findings suggest that region-specific lateralization of neuronal networks expressing opioid peptides underlyes in part lateralization of higher functions including positive and negative emotions and pain in the human brain.
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| 6. |
- Alm, Henrik, et al.
(author)
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Exposure to brominated flame retardant PBDE-99 affects cytoskeletal protein expression in the neonatal mouse cerebral cortex
- 2008
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In: Neurotoxicology. - : Elsevier BV. - 0161-813X .- 1872-9711. ; 29:4, s. 628-637
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Journal article (peer-reviewed)abstract
- Polybrominated diphenyl ethers (PBDEs) are environmental contaminants found in human and animal tissues worldwide. Neonatal exposure to the flame retardant 2,2', 4,4',5-pentabromodiphenyl ether (PBDE-99) disrupts normal brain development in mice, and results in disturbed spontaneous behavior in the adult. The mechanisms underlying the late effects of early exposure are not clear. To gain insight into the initial neurodevelopmental damage inflicted by PBDE-99, we investigated the short-term effects of PBDE-99 on protein expression in the developing cerebral cortex of neonatal mice, and the cytotoxic and apoptotic effects of PBDE-99 in primary cultures of fetal rat cortical cells. We used two-dimensional difference gel electrophoresis (2D-DIGE) to analyze protein samples isolated from the cortex of NMRI mice 24h after exposure to a single oral dose of 12 mg/kg PBDE-99 on post-natal day 10. Protein resolution was enhanced by sample pre-fractionation. In the cell model, we determined cell viability using the trypan blue exclusion assay, and apoptosis using immunocytochemical detection of cleaved caspase-3. We determined the identity of 111 differentially expressed proteins, 32 (29%) of which are known to be cytoskeleton-related. Similar to previous findings in the striatum, we found elevated levels of the neuron growth-associated protein Gap43 in the cortex. In cultured cortical cells, a high concentration of PBDE-99 (30 microM) induced cell death without any apparent increase in caspase-3 activity. These results indicate that the permanent neurological damage induced by PBDE-99 during the brain growth spurt involve detrimental effects on cytoskeletal regulation and neuronal maturation in the developing cerebral cortex.
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| 7. |
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| 8. |
- Alm, Henrik, et al.
(author)
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In Vitro Neurotoxicity of PBDE-99 : Immediate and Concentration-Dependent Effects on Protein Expression in Cerebral Cortex Cells
- 2010
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In: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 9:3, s. 1226-1235
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Journal article (peer-reviewed)abstract
- Polybrominated diphenyl ethers (PBDEs) are commonly used flame retardants in various consumer products. Pre- and postnatal exposure to congeners of PBDEs disrupts normal brain development in rodents. Two-dimensional difference gel electrophoresis (2D-DIGE) was used to analyze concentration-dependent differences in protein expression in cultured cortical cells isolated from rat fetuses (GD 21) after 24 h exposure to PBDE-99 (3, 10, or 30 muM). Changes on a post-translational level were studied using a 1 h exposure to 30 muM PBDE-99. The effects of 24 h exposure to 3 and 30 muM PBDE-99 on mRNA levels were measured using oligonucleotide microarrays. A total of 62, 46, and 443 proteins were differentially expressed compared to controls after 24 h of exposure to 3, 10, and 30 muM PDBE-99, respectively. Of these, 48, 43, and 238 proteins were successfully identified, respectively. We propose that the biological effects of low-concentration PBDE-99 exposure are fundamentally different than effects of high-concentration exposure. Low-dose PBDE-99 exposure induced marked effects on cytoskeletal proteins, which was not correlated to cytotoxicity or major morphological effects, suggesting that other more regulatory aspects of cytoskeletal functions may be affected. Interestingly, 0.3 and 3 muM, but not 10 or 30 muM increased the expression of phosphorylated (active) Gap43, perhaps reflecting effects on neurite extension processes.
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| 9. |
- Andersson, Jörgen, 1973, et al.
(author)
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Microstructure development during tempering of the hot-work tool steel Uddeholm QRO 90 Supreme
- 2009
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In: Proc. 8th Int Tooling Conf., Eds. P Beiss, C Broeckmann, S Franke and B Keysselitz, RWTH Aachen Univ, Aachen, Germany. - 3861307006 ; II, s. 611-623
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Conference paper (peer-reviewed)
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| 10. |
- Andrén, Daniel, 1973-
(author)
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On the Ising problem and some matrix operations
- 2007
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Doctoral thesis (other academic/artistic)abstract
- The first part of the dissertation concerns the Ising problem proposed to Ernst Ising by his supervisor Wilhelm Lenz in the early 20s. The Ising model, or perhaps more correctly the Lenz-Ising model, tries to capture the behaviour of phase transitions, i.e. how local rules of engagement can produce large scale behaviour. Two decades later Lars Onsager solved the Ising problem for the quadratic lattice without an outer field. Using his ideas solutions for other lattices in two dimensions have been constructed. We describe a method for calculating the Ising partition function for immense square grids, up to linear order 320 (i.e. 102400 vertices). In three dimensions however only a few results are known. One of the most important unanswered questions is at which temperature the Ising model has its phase transition. In this dissertation it is shown that an upper bound for the critical coupling Kc, the inverse absolute temperature, is 0.29 for the tree dimensional cubic lattice. To be able to get more information one has to use different statistical methods. We describe one sampling method that can use simple state generation like the Metropolis algorithm for large lattices. We also discuss how to reconstruct the entropy from the model, in order to obtain parameters as the free energy. The Ising model gives a partition function associated with all finite graphs. In this dissertation we show that a number of interesting graph invariants can be calculated from the coefficients of the Ising partition function. We also give some interesting observations about the partition function in general and show that there are, for any N, N non-isomorphic graphs with the same Ising partition function. The second part of the dissertation is about matrix operations. We consider the problem of multiplying them when the entries are elements in a finite semiring or in an additively finitely generated semiring. We describe a method that uses O(n3 / log n) arithmetic operations. We also consider the problem of reducing n x n matrices over a finite field of size q using O(n2 / logq n) row operations in the worst case.
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| 11. |
- Andren, Henrik, et al.
(author)
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Activity patterns of Eurasian lynx are modulated by light regime and individual traits over a wide latitudinal range
- 2014
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9
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Journal article (peer-reviewed)abstract
- 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 factors. Here we considered a range of variables that might potentially influence the activity of a large carnivore, the Eurasian lynx, in a network of studies conducted with identical methodology in different areas spanning latitudes from 49 degrees 7'N in central Europe to 70 degrees 00'N in northern Scandinavia. The variables considered both light conditions, ranging from a day with a complete day-night cycle to polar night and polar day, as well as individual traits of the animals. We analysed activity data of 38 individual free-ranging lynx equipped with GPS-collars with acceleration sensors, covering more than 11,000 lynx days. Mixed linear additive models revealed that the lynx activity level was not influenced by the daily daylight duration and the activity pattern was bimodal, even during polar night and polar day. The duration of the active phase of the activity cycle varied with the widening and narrowing of the photoperiod. Activity varied significantly with moonlight. Among adults, males were more active than females, and subadult lynx were more active than adults. In polar regions, the amplitude of the lynx daily activity pattern was low, likely as a result of the polycyclic activity pattern of their main prey, reindeer. At lower latitudes, the basic lynx activity pattern peaked during twilight, corresponding to the crepuscular activity pattern of the main prey, roe deer. Our results indicated that the basic activity of lynx is independent of light conditions, but is modified by both individual traits and the activity pattern of the locally most important prey.
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| 12. |
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| 13. |
- Andren, Henrik, et al.
(author)
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Analysis of replication casting of ice surfaces
- 2007
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In: Proceeding of the 8th International Symposium on Cold Region Development. - : Tampere University of Technology. - 9789517584821
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Conference paper (peer-reviewed)abstract
- The microscopic analysis of an ice surface is very difficult, due to the nature of the ice. The optically transparent, brittle and very environmentally sensitive surface is hard to analyze in a manner that does not render the results useless from damage or errors in measurements.The ice surface is ill suited for contact microscopy, like Atomic Force Microscopy (AFM) or other methods of sliding a probe over the surface. Furthermore the ice surface is transparent, so even cold room optical microscopy is not feasible. Due to the vacuous atmosphere Scanning Electron Microscope (SEM) is not an option. In this paper the authors look at some casting techniques to try and reproduce the surface with a substance much better suited for optical and mechanical measurements, as well as having a longer shelf life and being easier to handle. Different evaluations have been considered, where the frequency information is used as a measure of resolution, comparing the resolution loss of different casting materials.The casting materials used are different products from the dental industry, as well as polyvinyl formvar, a dissolved polymer that is very useful for casting of ice surfaces.
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| 14. |
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| 15. |
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| 16. |
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| 17. |
- Andren, Henrik, et al.
(author)
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Beskattningsmodell för järv : prognoser för järvpopulationen 2021 vid olika beskattningsnivåer under 2020
- 2020
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Reports (other academic/artistic)abstract
- Naturvårdsverket uppdrog (Ärende NV-04217-20, Kontrakt 331-20-004) åt Jens Persson och Henrik Andrén vid SLU, Institutionen för ekologi, Grimsö Forskningsstation att prognostisera järvpopulationen 2021 vid olika beskattningsnivåer under 2020 för Sverige och dessutom för Norrbottens, Västerbottens, Jämtlands län samt sammantaget för övriga län med järvförekomst (Västernorrlands, Dalarnas, Gävleborgs och Värmlands län).
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| 18. |
- Andren, Henrik
(author)
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Beskattningsmodell för lodjur: prognoser för den svenska lodjurspopulationen 2022 vid olika beskattningsnivåer under 2021
- 2020
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Reports (other academic/artistic)abstract
- Naturvårdsverket uppdrog (Ärendenummer NV-05689-20, Kontraktsnummer 331-20-006) åt Henrik Andrén vid SLU, Institutionen för ekologi, Grimsö Forskningsstation att prognostisera lodjurspopulationen för vintern 2021/2022 vid olika beskattningsnivåer (både totalt antal lodjur och honkvoter) under 2021 för respektive Rovdjursförvaltningsområde (RFO), och dessutom för det norra förvaltningsområdet presentera prognoser för respektive län och för olika längd på tidsserierna.
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| 19. |
- Andren, Henrik, et al.
(author)
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Beskattningsmodell för järv. Prognoser för järvpopulationen 2021 vid olika beskattningsnivåer under 2020 Version 2
- 2020
-
Reports (other academic/artistic)abstract
- Naturvårdsverket uppdrog (Ärende NV-04217-20, Kontrakt 331-20-004) åt Jens Persson och Henrik Andrén vid SLU, Institutionen för ekologi, Grimsö Forskningsstation att prognostisera järvpopulationen 2021 vid olika beskattningsnivåer under 2020 för Sverige och dessutom för Norrbottens, Västerbottens, Jämtlands län samt sammantaget för övriga län med järvförekomst (Västernorrlands, Dalarnas, Gävleborgs och Värmlands län).
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| 20. |
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| 21. |
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| 22. |
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| 23. |
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| 24. |
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| 25. |
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| 26. |
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| 27. |
- Andren, Henrik
(author)
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Beskattningsmodell för lodjur : prognoser för den svenska lodjurspopulationen 2022 vid olika beskattningsnivåer under 2021
- 2019
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Reports (other academic/artistic)abstract
- Naturvårdsverket uppdrog (Ärendenummer NV-05689-20, Kontraktsnummer 331-20-006) åt Henrik Andrén vid SLU, Institutionen för ekologi, Grimsö Forskningsstation att prognostisera lodjurspopulationen för vintern 2021/2022 vid olika beskattningsnivåer (både totalt antal lodjur och honkvoter) under 2021 för respektive Rovdjursförvaltningsområde (RFO), och dessutom för det norra förvaltningsområdet presentera prognoser för respektive län och för olika längd på tidsserierna.
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| 28. |
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| 29. |
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| 30. |
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| 31. |
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| 32. |
- Andren, Henrik
(author)
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Can we save large carnivores without losing large carnivore science?
- 2017
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In: Food Webs. - : Elsevier BV. - 2352-2496. ; 12, s. 64-75
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Journal article (peer-reviewed)abstract
- Large carnivores are depicted to shape entire ecosystems through top-down processes. Studies describing these processes are often used to support interventionist wildlife management practices, including carnivore reintroduction or lethal control programs. Unfortunately, there is an increasing tendency to ignore, disregard or devalue fundamental principles of the scientific method when communicating the reliability of current evidence for the ecological roles that large carnivores may play, eroding public confidence in large carnivore science and scientists. Here, we discuss six interrelated issues that currently undermine the reliability of the available literature on the ecological roles of large carnivores: (1) the overall paucity of available data, (2) reliability of carnivore population sampling techniques, (3) general disregard for alternative hypotheses to top-down forcing, (4) lack of applied science studies, (5) frequent use of logical fallacies, and (6) generalisation of results from relatively pristine systems to those substantially altered by humans. We first describe how widespread these issues are, and given this, show, for example, that evidence for the roles of wolves (Canis lupus) and dingoes (Canis lupus dingo) in initiating trophic cascades is not as strong as is often claimed. Managers and policy makers should exercise caution when relying on this literature to inform wildlife management decisions. We emphasise the value of manipulative experiments and discuss the role of scientific knowledge in the decision-making process. We hope that the issues we raise here prompt deeper consideration of actual evidence, leading towards an improvement in both the rigour and communication of large carnivore science.
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| 33. |
- Andren, Henrik, et al.
(author)
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De stora rovdjurens effekter på annat vilt och tamren
- 2018
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Reports (other academic/artistic)abstract
- Den teoretiska bakgrunden ger en beskrivning av termer och fackuttryck, samt beskrivningar av hur olika faktorer påverkar relationerna mellan rovdjur och bytesdjur. Termen predator är synonymt med rovdjur, medan termen predation står för den process som består av dödande och konsumtion av bytesdjur, och omfattningen av den dödlighet hos bytesdjuren som rovdjuret orsakar. Rovdjurens påverkan på bytespopulationer varierar mellan områden och över tid, samtidigt som rovdjuren själva påverkas av bytespopulationerna. Rovdjur-bytesdjurssystemen är alltså inte bara dynamiska utan också interaktiva, d.v.s. de påverkar varandra. Rovdjurens påverkan på bytespopulationen beror i princip på fem faktorer: (1) bytespopulationens storlek, (2) bytespopulationens produktivitet/tillväxttakt, (3) rovdjurspopulationens storlek, (4) rovdjurspopulationens produktivitet/tillväxttakt samt (5) antalet bytesdjur tagna per rovdjur och tidsenhet (den s.k. funktionella responsen). Predation är ofta en kombination av additiv och kompensatorisk dödlighet. Med additiv dödlighet menar man att predationen läggs ovanpå (adderas till) annan dödlighet, med kompensatorisk dödlighet menar man att predationen ersätter annan typ av dödlighet. Ju större andel av predationen som är additiv desto större blir effekterna på bytesdjuren. Rovdjuren kan påverka sina bytesdjur inte bara genom direkt predation utan även genom att bytesdjuren ändrar sitt beteende i närvaron av rovdjuren. Rovdjuren är en del av ekosystemet, som förenklat består av producenter (växter), primärkonsumenter (växtätare) och sekundärkonsumenter (predatorer). Dessa delar kan också beskrivas som olika trofinivåer i ekosystemet. En mer komplex beskrivning av ett ekosystem är att arter är ordnade i ett nätverk av interaktioner både mellan och inom trofiska nivåer, s.k. näringsvävar. I komplexa näringsvävar ökar antalet interaktioner mellan arter både inom trofinivåer och mellan trofinivåer, vilket försvagar specifika interaktioner mellan enskilda arter. I Sverige saknas stora områden som är helt opåverkade av mänskliga aktiviteter, vilket gör människan till den viktigaste aktören för storskalig påverkan på ekosystem över hela landet. Människan påverkar ekosystemet på många sätt, t.ex. genom markanvändning, jakt, andra ingrepp och förvaltningsåtgärder, och kan helt förändra dynamiken mellan rovdjur och bytesdjur.Även ett kortfaktablad om rovdjurens effekter finns att ladda ned.Hur påverkar de stora rovdjuren bytesdjurens populationer?Grimsö forskningsstation vid Sveriges lantbruksuniversitet (SLU) har för Naturvårdsverkets räkning gjort en översikt av kunskapsläget om hur de stora rovdjuren påverkar de bytesdjur de jagar, det vill säga vilt och tamren. Hela rapporten, De stora rovdjurens effekter på annat vilt och tamren, kan du läsa här, eller på Naturvårdsverkets hemsida.
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| 34. |
- Andren, Henrik, et al.
(author)
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Effect of supplemental feeding on habitat and crop selection by wild boar in Sweden
- 2023
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In: Ethology Ecology & Evolution. - : Informa UK Limited. - 0394-9370 .- 1828-7131. ; 35, s. 106-124
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Journal article (peer-reviewed)abstract
- The wild boar population has increased rapidly during the last 2 decades in Southern and Central Sweden. This rise in population size has caused severe damages to agricultural fields through their foraging behavior. Given the hierarchical nature of habitat and resource selection, wildlife management needs to understand the selection on both levels to better understand the ecology of nuisance species and mitigate the damages they infer. Thus, there is an urgent need for more knowledge on the factors that influence habitat selection as a tool in the evidence-based management of wild boar to reduce the losses they cause in the agricultural sector. This study aims to evaluate a common management action (feeding stations) influencing wild boar selection of (1) habitats and (2) resources i.e., crop types, in South-Central Sweden during summer. Eleven wild boars were fitted with GPS/GSM-collars to record movement among different habitats and crops. Wild boar shows a high preference for clear-cuts, agricultural fields, and deciduous forests. The animals showed a high preference for crop fields with oat, spring wheat, and mixed crops. A binary logistic model revealed both a positive and negative significant influence of distance to feeding stations on the selection of different habitats and crop fields. In general, feeding stations influenced the selection of different habitats and crops negatively i.e., the closer a habitat or crop field is to a feeding station, the higher the likelihood of its selection. The study recommends adjustments to wild boar management and cropping systems to reduce damages on highly selected crop fields.
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| 35. |
- Andren, Henrik
(author)
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Environmental and seasonal correlates of capercaillie movement traits in a Swedish wind farm
- 2021
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In: Ecology and Evolution. - : Wiley. - 2045-7758. ; 11, s. 11762-11773
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Journal article (peer-reviewed)abstract
- Animals continuously interact with their environment through behavioral decisions, rendering the appropriate choice of movement speed and directionality an important phenotypic trait. Anthropogenic activities may alter animal behavior, including movement. A detailed understanding of movement decisions is therefore of great relevance for science and conservation alike. The study of movement decisions in relation to environmental and seasonal cues requires continuous observation of movement behavior, recently made possible by high-resolution telemetry. We studied movement traits of 13 capercaillie (Tetrao urogallus), a mainly ground-moving forest bird species of conservation interest, over two summer seasons in a Swedish windfarm using high-resolution GPS tracking data (5-min sampling interval). We filtered and removed unreliable movement steps using accelerometer data and step characteristics. We explored variation in movement speed and directionality in relation to environmental and seasonal covariates using generalized additive mixed models (GAMMs). We found evidence for clear daily and seasonal variation in speed and directionality of movement that reflected behavioral adjustments to biological and environmental seasonality. Capercaillie moved slower when more turbines were visible and faster close to turbine access roads. Movement speed and directionality were highest on open bogs, lowest on recent clear-cuts (<5 y.o.), and intermediate in all types of forest. Our results provide novel insights into the seasonal and environmental correlates of capercaillie movement patterns and supplement previous behavioral observations on lekking behavior and wind turbine avoidance with a more mechanistic understanding.
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| 36. |
- Andren, Henrik, et al.
(author)
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Integrating animal tracking datasets at a continental scale for mapping Eurasian lynx habitat
- 2023
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In: Diversity and Distributions. - 1366-9516 .- 1472-4642. ; 29, s. 1546-1560
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Journal article (peer-reviewed)abstract
- 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 different environmental contexts must be reconciled. Here, we compare approaches for large-area habitat mapping and assess available habitat for a recolonizing large carnivore, the Eurasian lynx (Lynx lynx).LocationEurope.Methods We use a continental-scale animal tracking database (450 individuals from 14 study sites) to systematically assess modelling approaches, comparing (1) global strategies that pool all data for training versus building local, site-specific models and combining them, (2) different approaches for incorporating regional variation in habitat selection and (3) different modelling algorithms, testing nonlinear mixed effects models as well as machine-learning algorithms.Results Testing models on training sites and simulating model transfers, global and local modelling strategies achieved overall similar predictive performance. Model performance was the highest using flexible machine-learning algorithms and when incorporating variation in habitat selection as a function of environmental variation. Our best-performing model used a weighted combination of local, site-specific habitat models. Our habitat maps identified large areas of suitable, but currently unoccupied lynx habitat, with many of the most suitable unoccupied areas located in regions that could foster connectivity between currently isolated populations.Main Conclusions We demonstrate that global and local modelling strategies can achieve robust habitat models at the continental scale and that considering regional variation in habitat selection improves broad-scale habitat mapping. More generally, we highlight the promise of large wildlife tracking databases for large-area habitat mapping. Our maps provide the first high-resolution, yet continental assessment of lynx habitat across Europe, providing a consistent basis for conservation planning for restoring the species within its former range.
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| 37. |
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| 38. |
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| 39. |
- Andren, Henrik, et al.
(author)
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Large carnivore expansion in Europe is associated with human population density and land cover changes
- 2021
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In: Diversity and Distributions. - : Wiley. - 1366-9516 .- 1472-4642. ; 27, s. 602-617
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Journal article (peer-reviewed)abstract
- Aim: The recent recovery of large carnivores in Europe has been explained as resulting from a decrease in human persecution driven by widespread rural land abandonment, paralleled by forest cover increase and the consequent increase in availability of shelter and prey. We investigated whether land cover and human population density changes are related to the relative probability of occurrence of three European large carnivores: the grey wolf (Canis lupus), the Eurasian lynx (Lynx lynx) and the brown bear (Ursus arctos).Location: Europe, west of 64 degrees longitude.Methods: We fitted multi-temporal species distribution models using >50,000 occurrence points with time series of land cover, landscape configuration, protected areas, hunting regulations and human population density covering a 24-year period (1992-2015). Within the temporal window considered, we then predicted changes in habitat suitability for large carnivores throughout Europe.Results: Between 1992 and 2015, the habitat suitability for the three species increased in Eastern Europe, the Balkans, North-West Iberian Peninsula and Northern Scandinavia, but showed mixed trends in Western and Southern Europe. These trends were primarily associated with increases in forest cover and decreases in human population density, and, additionally, with decreases in the cover of mosaics of cropland and natural vegetation.Main conclusions: Recent land cover and human population changes appear to have altered the habitat suitability pattern for large carnivores in Europe, whereas protection level did not play a role. While projected changes largely match the observed recovery of large carnivore populations, we found mismatches with the recent expansion of wolves in Central and Southern Europe, where factors not included in our models may have played a dominant role. This suggests that large carnivores' co-existence with humans in European landscapes is not limited by habitat availability, but other factors such as favourable human tolerance and policy.
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| 40. |
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| 41. |
- Andren, Henrik, et al.
(author)
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Large impact of Eurasian lynx predation on roe deer population dynamics
- 2015
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10
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Journal article (peer-reviewed)abstract
- The effects of predation on ungulate populations depend on several factors. One of the most important factors is the proportion of predation that is additive or compensatory respectively to other mortality in the prey, i.e., the relative effect of top-down and bottom-up processes. We estimated Eurasian lynx (Lynx lynx) kill rate on roe deer (Capreolus capreolus) using radio-collared lynx. Kill rate was strongly affected by lynx social status. For males it was 4.85 +/- 1.30 S.E. roe deer per 30 days, for females with kittens 6.23 +/- 0.83 S.E. and for solitary females 2.71 +/- 0.47 S.E. We found very weak support for effects of prey density (both for Type I (linear) and Type II (non-linear) functional responses) and of season (winter, summer) on lynx kill rate. Additionally, we analysed the growth rate in a roe deer population from 1985 to 2005 in an area, which lynx naturally re-colonized in 1996. The annual roe deer growth rate was lower after lynx re-colonized the study area, but it was also negatively influenced by roe deer density. Before lynx colonized the area roe deer growth rate was lambda = 1.079 (+/- 0.061 S.E.), while after lynx re-colonization it was lambda = 0.94 (+/- 0.051 S.E.). Thus, the growth rate in the roe deer population decreased by Delta lambda = 0.14 (+/- 0.080 S.E.) after lynx re-colonized the study area, which corresponded to the estimated lynx predation rate on roe deer (0.11 +/- 0.042 S.E.), suggesting that lynx predation was mainly additive to other mortality in roe deer. To conclude, this study suggests that lynx predation together with density dependent factors both influence the roe deer population dynamics. Thus, both top-down and bottom-up processes operated at the same time in this predator-prey system.
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| 42. |
- Andren, Henrik, et al.
(author)
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Lodjur i dagens Sverige
- 2014
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In: Lodjuret. - 9789173536547 ; , s. 163-186
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Book chapter (pop. science, debate, etc.)
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| 43. |
- Andren, Henrik, et al.
(author)
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Modelling the combined effect of an obligate predator and a facultative predator on a common prey: lynx Lynx lynx and wolverine Gulo gulo predation on reindeer Rangifer tarandus
- 2011
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In: Wildlife Biology. - : Wiley. - 0909-6396 .- 1903-220X. ; 17, s. 33-43
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Journal article (peer-reviewed)abstract
- In conservation and management of large predators, effects of species are often considered separately. However, predators often interact with one another in different ways (e.g. interspecific competition, intra guild predation and kleptoparasitism) that may influence the total predation on a common prey. We estimated the total number of semi-domestic reindeer Rangifer tarandus killed by Eurasian lynx Lynx lynx and wolverine Gulo gulo at different relative abundances of the two species using a model based on diet, food requirements of lynx and wolverine and amount of food available on a reindeer. Our model suggests that total predation decreases by approximately 7.9% (+/- 4.8 SD) if wolverines scavenge on lynx-killed reindeer, compared to a model without scavenging. If the management goal is a constant number of predators, the model suggests that the total kill rate will be lowest in areas with only wolverines, as the estimated wolverine kill rate is much lower than the lynx kill rate. Our model showed that it is unlikely that the lowest number of reindeer killed per predator individual will be at a certain lynx-wolverine ratio, which would appear if lynx consumption of killed reindeer is low and wolverines are very efficient finding lynx-killed reindeer. However, if the management goal is a constant number of lynx and wolverines, the model suggests that the total predation is lower, if lynx and wolverines coexist in the same area compared to existing separately in different areas. The total predation by wolverine and lynx on reindeer is very important for the management of lynx and wolverine in the reindeer husbandry area in Sweden, as the current compensation scheme for predator-killed semi-domestic reindeer is based on the number of predators present within a reindeer herding district, and the compensation for wolverine and lynx is added independently of one another.
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| 44. |
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| 45. |
- Andren, Henrik, et al.
(author)
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No Allee effect detected during the natural recolonization by a large carnivore despite low growth rate
- 2022
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In: Ecosphere. - : Wiley. - 2150-8925 .- 2150-8925. ; 13:3
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Journal article (peer-reviewed)abstract
- Eurasian lynx (Lynx lynx) have recently naturally recolonized southern Sweden. The first documented reproduction of lynx in recent times occurred in 2003, and the population increased from 2 to 48 family groups (the unit of measurement in Swedish monitoring) during its first 18 years (2003/2004–2020/2021). We did not detect any Allee effect, that is, lower growth rate at low population density, during the recolonization of southern Sweden, although our population simulations revealed a non-negligible (30%) chance that population observed development could include an Allee effect. The probable absence of an Allee effect was likely because colonizing females did not lack mating partners, as a larger number of wide-ranging males were established in the area before documented reproduction took place. Despite the absence of an Allee effect, the growth rate during recolonization was lower in southern Sweden (λ = 1.20) than in central Sweden (λ = 1.29). We have no evidence of higher mortality, including that from poaching, or lower reproduction in southern Sweden could explain the lower growth rate. Instead, we suggest that the lower growth rate during the recolonization of southern Sweden was explained by fewer immigrants arriving from central Sweden due to areas of less suitable habitat between central and southern Sweden, partially preventing immigration southward. From a conservation point of view, it is positive that this small population could recover without being negatively influenced by an Allee effect, as small populations with an Allee effect experience lower viability than those without.
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| 46. |
- Andren, Henrik, et al.
(author)
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Numerical response of predator to prey: Dynamic interactions and population cycles in Eurasian lynx and roe deer
- 2024
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In: Ecological Monographs. - 0012-9615 .- 1557-7015. ; 94
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Journal article (peer-reviewed)abstract
- The dynamic interactions between predators and their prey have two fundamental processes: numerical and functional responses. Numerical response is defined as predator growth rate as a function of prey density or both prey and predator densities [dP/dt = f(N, P)]. Functional response is defined as the kill rate by an individual predator being a function of prey density or prey and predator densities combined. Although there are relatively many studies on the functional response in mammalian predators, the numerical response remains poorly documented. We studied the numerical response of Eurasian lynx (Lynx lynx) to various densities of its primary prey species, roe deer (Capreolus capreolus), and to itself (lynx). We exploited an unusual natural situation, spanning three decades where lynx, after a period of absence in central and southern Sweden, during which roe deer populations had grown to high densities, subsequently recolonized region after region, from north to south. We divided the study area into seven regions, with increasing productivity from north to south. We found strong effects of both roe deer density and lynx density on lynx numerical response. Thus, both resources and intraspecific competition for these resources are important to understanding the lynx population dynamic. We built a series of deterministic lynx-roe deer models, and applied them to the seven regions. We found a very good fit between these Lotka-Volterra type models and the data. The deterministic models produced almost cyclic dynamics or dampened cycles in five of the seven regions. Thus, we documented population cycles in this large predator-large herbivore system, which is rarely done. The amplitudes in the dampened cycles decreased toward the south. Thus, the dynamics between lynx and roe deer became more stable with increasing carrying capacity for roe deer, which is related to higher productivity in the environment. This increased stability could be explained by variation in predation risk, where human presence can act as prey refugia, and by a more diverse prey guild that will weaken the direct interaction between lynx and roe deer.
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| 47. |
- Andren, Henrik
(author)
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One size fits all: Eurasian lynx females share a common optimal litter size
- 2014
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In: Journal of Animal Ecology. - : Wiley. - 0021-8790 .- 1365-2656. ; 83, s. 107-115
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Journal article (peer-reviewed)abstract
- 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 size is adaptive because each female has its own optimal clutch size associated with its intrinsic ability to raise offspring. Although Lack litter size and condition-dependent litter size are presented as two competing models, both are based on the concept of individual optimization. We propose a unified optimal litter size model (called adaptive litter size') and identify a set of conditions under which a common vs. a state-dependent optimal litter size should be observed. We test whether females of Eurasian lynx (Lynx lynx) have a common optimal litter size, or whether they adjust their litter size according to their state. We used a detailed individual-based data set collected from contrasting populations of Eurasian lynx in Scandinavia. Observed reproductive patterns in female lynx provide strong support for the existence of a common optimal litter size. Litter size did not vary according to female body mass or reproductive category, or among contrasted populations and years. A litter size of 2 was associated with a higher fitness than both smaller and larger litters, and thus corresponded to the adaptive litter size' for female lynx. We suggest that the reproductive pattern of female lynx might correspond to a risk avoidance tactic common to all individuals, which has evolved in response to strong environmental constraints generated by a highly unpredictable food supply during lactation.
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| 48. |
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| 49. |
- Andren, Henrik, et al.
(author)
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Prerequisites for coexistence: human pressure and refuge habitat availability shape continental‑scale habitat use patterns of a large carnivore
- 2023
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In: Landscape Ecology. - 0921-2973 .- 1572-9761. ; 38, s. 1713–1728-
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Journal article (peer-reviewed)abstract
- ContextAdjustments 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 human pressure and landscape composition are lacking.ObjectivesHere, we investigate adjustments in habitat use by Eurasian lynx (Lynx lynx) in response to varying availability of refuge habitats (i.e., forests and rugged terrain) and human landscape modification.MethodsUsing a large tracking dataset including 434 individuals from seven populations, we assess functional responses in lynx habitat use across two spatial scales, testing for variation by sex, daytime, and season.ResultsWe found that lynx use refuge habitats more intensively with increasing landscape modification across spatial scales, selecting forests most strongly in otherwise open landscapes and rugged terrain in mountainous regions. Moreover, higher forest availability enabled lynx to place their home ranges in more human-modified landscapes. Human pressure and refuge habitat availability also shaped temporal patterns of lynx habitat use, with lynx increasing refuge habitat use and reducing their use of human-modified areas during periods of high exposure (daytime) or high vulnerability (postnatal period) to human pressure.ConclusionsOur findings suggest a remarkable adaptive capacity of lynx towards human pressure and underline the importance of refuge habitats across scales for enabling coexistence between large carnivores and people. More broadly, we highlight that the composition of landscapes determines how large carnivores can adapt to human pressure and thus play an important role shaping large carnivore habitat use and distributions.
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