| 1. |
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| 2. |
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| 3. |
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| 4. |
- Andren, Henrik, et al.
(författare)
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De stora rovdjurens effekter på annat vilt och tamren
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)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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| 5. |
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| 6. |
- Andren, Henrik, et al.
(författare)
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Large impact of Eurasian lynx predation on roe deer population dynamics
- 2015
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10
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Tidskriftsartikel (refereegranskat)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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| 7. |
- Andren, Henrik, et al.
(författare)
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Lodjur i dagens Sverige
- 2014
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Ingår i: Lodjuret. - 9789173536547 ; , s. 163-186
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Bokkapitel (populärvet., debatt m.m.)
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| 8. |
- Andren, Henrik, et al.
(författare)
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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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Ingår i: Ecological Monographs. - 0012-9615 .- 1557-7015. ; 94
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Tidskriftsartikel (refereegranskat)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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| 9. |
- Andren, Henrik, et al.
(författare)
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Prognoser för vargpopulationen hösten 2021 – uppdatering 2020-11-12
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- På uppdrag från Naturvårdsverket (Ärende nr. NV-08390-20) har Henrik Andrén, Håkan Sand och Olof Liberg gjort en uppdatering av prognoserna för vargpopulationen hösten 2021 vid olika jaktuttag under säsongen 2020/2021. I uppdraget ingick också att beskriva hur man beräknar tillväxttakten och olika spridningsmått för tillväxttakten, d.v.s. osäkerheten eller mellanårsvariationen i tillväxttakten.
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| 10. |
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| 11. |
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| 12. |
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| 13. |
- Aronson, Åke, et al.
(författare)
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Ulv i Skandinavia : Statusrapport for vinteren 2009-2010
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The wolves in Sweden and Norway are members of a joint Scandinavian wolf population. In a combined Swedish-Norwegian monitoring project, wolves on the Scandinavian Peninsula were located and counted during the winter of 2009-2010. In Sweden, County administrative boards perform the fieldwork and collection of field data (snow-tracking, DNA-samples), whereas the Wildlife Damage Center (VSC) at Grimsö Research Station was responsible for evaluating and summarizing the results of the wolf monitoring. In Norway, wolf biologists at Hedmark University College and a genetist at Rovdata (Trondheim) in cooperation with the Norwegian Nature Inspectorate (SNO) were responsible for the monitoring of resident and non-resident wolves, respectively. Furthermore, cooperative wolf pack monitoring has been carried out in Fennoscandia in collaboration with Finland. A large number of volunteers and organizations such as hunting associations in both countries and the Swedish Carnivore Association also report observations and participate in wolf monitoring activities. The estimated number of wolves in Scandinavia is mainly based on long distances of ground tracking on snow, but also by radio-telemetry and DNA-analysis. The estimate was restricted to the period of October 1, 2009 – February 28, 2010. To guarantee the quality of the reports used, the majority have been checked in the field by the project, or by other personnel with experience of ground tracking wolves on snow. Wolves were classified as 1) family groups (packs), 2) scent-marking pairs, 3) other resident wolves, or 4) other wolves. The results were presented as minimum-maximum numbers where the minimum was exclusively based on confirmed field-checked reports, while the maximum also included other reports. A total of 252-291 wolves were estimated on the Scandinavian Peninsula during the 2009-2010 winter. Among these, 28 packs included 165-175 wolves, and 44-49 wolves belonged to 21-24 scent-marking pairs. The majority of the wolves (186-215) were located in Sweden. Of the 33-39 wolves restricted to Norway, 21-23 were members of 3 packs, 6 were scent-marking pair members, none were classified as “other resident wolves”, and 6-10 were classified as “other wolves”. Areas were utilized on both sides of the national border between Sweden and Norway by 33-37 resident wolves. Successful reproduction in the spring of 2009 was confirmed in 26 of the Scandinavian wolf territories. Among these, 19 litters were born in Sweden, 4 litters was born in a transboundary packs, and 3 litters grew up in Norway. In 2009, two Finnish-Russian male wolves reproduced for the second time, one litter in Sweden (the Galven territory) and one in Norway (the Kynna territory). In Finland, during the winter 2009-10, a total of 76-78 wolves in 15 packs were estimated to have exclusively Finnish territories. In addition 72-74 wolves were pack members within 13 territories across the Finnish-Russian border
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| 14. |
- Aronson, Åke, et al.
(författare)
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Ulv i Skandinavia : statusrapport for vinteren 2010-2011
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The wolves in Sweden and Norway are members of a joint Scandinavian wolf population. In a combined Swedish-Norwegian monitoring project, wolves on the Scandinavian Peninsula were located and counted during the winter of 2010-2011. In Sweden, County administrative boards perform the fieldwork and collection of field data (snow-tracking, DNA-samples), whereas the Wildlife Damage Center (VSC) at Grimsö Research Station was responsible for evaluating and summarizing the results of the wolf monitoring. In Norway, wolf biologists at Hedmark University College and a genetist at Rovdata (Trondheim) in cooperation with the Norwegian Nature Inspectorate (SNO) were responsible for the monitoring of resident and non-resident wolves, respectively. Furthermore, cooperative wolf pack monitoring has been carried out in Fennoscandia in collaboration with Finland. A large number of volunteers and organizations such as hunting associations in both countries and the Swedish Carnivore Association also report observations and participate in wolf monitoring activities. The estimated number of wolves in Scandinavia is mainly based on long distances of ground tracking on snow, but also by DNA-analysis and radio-telemetry. The estimate was restricted to the period of October 1, 2010 – February 28, 2011. To guarantee the quality of the reports used, the majority have been checked in the field by the project, or by other personnel with experience of ground tracking wolves on snow. Wolves were classified as 1) family groups (packs), 2) scent-marking pairs, 3) other resident wolves, or 4) other wolves. The results were presented as minimum-maximum numbers where the minimum was exclusively based on confirmed field-checked reports, while the maximum also included other reports. A total of 289-325 wolves were estimated on the Scandinavian Peninsula during the 2010-2011 winter. Among these, 31 packs included 183-189 wolves, and 57-61 wolves belonged to 27-30 scent-marking pairs. The majority of the wolves (235-266) were located in Sweden, of which 149-154 were members of 25 packs, 43-44 lived in 20-22 scent-marking pairs, 4 were classified as “other resident wolves”, and 39-64 were classified as “other wolves”. Of the 32-34 wolves restricted to Norway, 18-19 were members of 3 packs, 8 were scent-marking pair members, one was classified as “other resident wolves”, and 5-6 were classified as “other wolves”. Another 22-25 resident wolves lived in 6-7 packs or scent-marking pairs in territories covering areas on both sides of the Swedish-Norwegian border. Successful reproduction in spring 2010 was confirmed in 31 of the Scandinavian wolf territories. Among these, 25 litters were born in Sweden, 3 litters were born in transboundary packs, and 3 litters grew up in Norway. In 2010, two Finnish-Russian male wolves reproduced for the third time, one litter in Sweden (the Galven territory) and one in Norway (the Kynna territory). In Finland, during the winter 2010-11, a total of 48 wolves in 8 packs were estimated to have exclusively Finnish territories. In addition 59-64 wolves were pack members within 11 territories across the Finnish-Russian border
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| 15. |
- Axelsson, Erik, et al.
(författare)
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The genomic signature of dog domestication reveals adaptation to a starch-rich diet
- 2013
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 495:7441, s. 360-364
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Tidskriftsartikel (refereegranskat)abstract
- The domestication of dogs. was an important episode in the development of human civilization. The precise timing and location of this event is debated(1-5) and little is known about the genetic changes that accompanied the transformation of ancient wolves into domestic dogs. Here we conduct whole-genome resequencimg of dogs and wolves to identify 3.8 million genetic variants used to identify 36 genomic regions that probably represent targets for selection during dog domestication. Nineteen of these regions contain genes important in brain function, eight of which belong to nervous system development pathways and potentially underlie behavioural changes central to dog domestication(6). Ten genes with key roles in starch digestion and fat metabolism also show signals of selection. We identify candidate mutations in key genes and provide functional support for an increased starch digestion in dogs relative to wolves. Our results indicate that novel adaptations allowing the early ancestors of modern dogs to thrive on a diet rich in starch, relative to the carnivorous diet of wolves, constituted a crucial step in the early domestication of dogs.
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| 16. |
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| 17. |
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| 18. |
- Chapron, Guillaume, et al.
(författare)
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Estimating wolf (Canis lupus) population size from number of packs and an individual based model
- 2016
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Ingår i: Ecological Modelling. - : Elsevier BV. - 0304-3800 .- 1872-7026. ; 339, s. 33-44
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Tidskriftsartikel (refereegranskat)abstract
- 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 time well informative on total population size. We show how total population size can be estimated from group counts by using an individual-based population model in a social living species. We developed a wolf (Canis lupus) specific Individual Based Model and used Approximate Bayesian Computation (ABC) to fit this population model to the time series of annual number of packs, reproductions and pairs obtained from Scandinavian monitoring data. Model informative priors were obtained with data from collared individuals by the Scandinavian wolf research project. The fitted model was then used to estimate a conversion factor from number of packs to total number of individuals and to number of reproductions. There was a good fit between the retained simulations by ABC and the observed Scandinavian wolf population trajectory. The fitted simulations returned a conversion factor of 8.0 (95% CI = 6.62-10.07) from number of packs to total population size and of 1.0 (95% CI = 0.93-1.12) to number of reproductions in December. A sensitivity analysis revealed that the conversion factor from packs to total population size was positively correlated with pup survival and litter size and negatively correlated with subadult, vagrant and adult survivals. Using an individual based model allowed us to model the full complexity of demographic traits of a social-living species such as the wolf. The flexibility of the model also meant that the conversion factor could be estimated for any month during the year. Our approach to estimate total population size from counts of groups requires having a population model where both individuals and groups are explicitly described and can be applied to other wolf populations and group-living species where counting all individuals over a large area is unfeasible.
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| 19. |
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| 20. |
- Chapron, Guillaume, et al.
(författare)
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Recovery of large carnivores in Europe's modern human-dominated landscapes
- 2014
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 346, s. 1517-1519
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Tidskriftsartikel (refereegranskat)abstract
- 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 large carnivore species, with stable or increasing abundance in most cases in 21st-century records. The reasons for this overall conservation success include protective legislation, supportive public opinion, and a variety of practices making coexistence between large carnivores and people possible. The European situation reveals that large carnivores and people can share the same landscape.
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| 21. |
- Erlinge, Sam, et al.
(författare)
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Can vertebrate predators regulate their prey?
- 1984
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Ingår i: The American Naturalist. ; 123:1, s. 125-133
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Tidskriftsartikel (refereegranskat)abstract
- Whether vertebrate predators can regulate their prey or not has long been a controversial question. At the one extreme it has been claimed that predators have no impact on prey numbers but consume only a doomed surplus (Errington 1946), and at the other that predators strongly interact with their prey causing either stable equilibria or cycles (Tanner 1975; Keith et al. 1977). However,.there are no field studies showing a regulatory effect of predation among vertebrates. Here we report on such a study.
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| 22. |
- Jonzén, Niclas, et al.
(författare)
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Sharing the bounty-Adjusting harvest to predator return in the Scandinavian human-wolf-bear-moose system
- 2013
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Ingår i: Ecological Modelling. - : Elsevier BV. - 0304-3800 .- 1872-7026. ; 265, s. 140-148
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Tidskriftsartikel (refereegranskat)abstract
- The increase and range extension of wolves (Canis lupus L) and brown bears ( Ursus arctos L) in Scandinavia inevitably impacts moose (Alces alces L.) populations and, as a consequence, the size and composition of the hunter harvest must be adjusted. We used a sex- and age-structured moose population model to delineate optimal harvest strategies under predation and to compare the resulting harvest composition with the strategy commonly implemented in practice. We examined how much moose density or adult sex ratio needs to change to fully compensate for losses to predation. We found a harvest allocation pattern in commonly used practical management across calves, bulls and cows that indicated a trade-off strategy between maximising the number of shot moose, the yield biomass and the number of shot prime bulls. This strategy performed quite well with respect to all yield measures and yielded an age structure most similar to the strategies maximising harvest biomass and prime bulls. Unless predation pressure was very high, the harvest loss could be completely compensated for by allowing a higher moose density. In other situations the current hunting strategy was not possible to implement and the moose density needed to sustain predation even without hunting increases dramatically. An alternative option to balance the predation loss was to accept a more female-biased sex ratio in the winter population. Hence, it may be possible to keep 50% calves in the harvest and still obtain the same total harvest if the proportion of bulls in the harvest is increased to compensate for predation. The increase of large carnivores competing with moose hunting creates conflicts and will inevitably reduce harvest yield unless hunting strategies change. We show how increased moose density and redistribution of the harvest towards bulls can mitigate this conflict and we provide a web-based tool, where stakeholders can compare the long-term effects of alternative management decisions and eventually adjust their hunting strategy accordingly. (C) 2013 Elsevier B.V. All rights reserved.
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| 23. |
- Kardos, Marty, et al.
(författare)
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Genomic consequences of intensive inbreeding in an isolated wolf population
- 2018
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Ingår i: Nature Ecology & Evolution. - : Springer Science and Business Media LLC. - 2397-334X. ; 2:1, s. 124-131
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Tidskriftsartikel (refereegranskat)abstract
- Inbreeding (mating between relatives) is a major concern for conservation as it decreases individual fitness and can increase the risk of population extinction. We used whole-genome resequencing of 97 grey wolves (Canis lupus) from the highly inbred Scandinavian wolf population to identify 'identical-by-descent' (IBD) chromosome segments as runs of homozygosity (ROH). This gave the high resolution required to precisely measure realized inbreeding as the IBD fraction of the genome in ROH (F-ROH). We found a striking pattern of complete or near-complete homozygosity of entire chromosomes in many individuals. The majority of individual inbreeding was due to long IBD segments (>5 cM) originating from ancestors <= 10 generations ago, with 10 genomic regions showing very few ROH and forming candidate regions for containing loci contributing strongly to inbreeding depression. Inbreeding estimated with an extensive pedigree (F-P) was strongly correlated with realized inbreeding measured with the entire genome (r(2) = 0.86). However, inbreeding measured with the whole genome was more strongly correlated with multi-locus heterozygosity estimated with as few as 500 single nucleotide polymorphisms, and with F-ROH estimated with as few as 10,000 single nucleotide polymorphisms, than with F-P. These results document in fine detail the genomic consequences of intensive inbreeding in a population of conservation concern.
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| 24. |
- Khan, Talha, et al.
(författare)
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BATTERY LIFE-TIME OPTIMIZATION FOR LOW POWER DEVICES
- 2022
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Patent (populärvet., debatt m.m.)abstract
- A network node determines a voltage response characteristic of the battery in a low powered user equipment and controls the activity pattern of the user equipment to align its activity pattern with the voltage response characteristic of the battery to extend the useful life of the battery in the user equipment.
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| 25. |
- Khan, Talha, et al.
(författare)
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BATTERY LIFE-TIME PREDICTION FOR LOW POWER DEVICES
- 2022
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Patent (populärvet., debatt m.m.)abstract
- A network node is configured to monitor battery usage on behalf of the low power device and to predict the SOC and remaining life-time for the batteries in the low power devices. The network nodes are fully powered and have the computational capacity to use more complex and accurate models that are not feasible for implementation in resource-limited devices. The network node can calculate the SOC and remaining life-time for a low power device and may also change the transmission and reception patterns for the device to extend the life-time of the battery.
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| 26. |
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| 27. |
- Kjellander, Petter, et al.
(författare)
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Age-specific variation in male breeding success of a territorial ungulate species, the European roe deer
- 2009
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Ingår i: Journal of Mammalogy. - 0022-2372 .- 1545-1542. ; 90, s. 661-665
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Tidskriftsartikel (refereegranskat)abstract
- We investigated age-specific variation in male yearly breeding success (YBS) using genetic estimates obtained from 2 populations of a territorial ungulate, the European roe deer (Capreolus capreolus). YBS in both populations was markedly age-structured, with 3 distinct stages, supporting the dome-shaped pattern of variation commonly reported for age-dependent variation in life-history traits of ungulates. YBS was low at 2 years of age, peaked at 3-8 years of age, and tended to decline afterwards (senescence). Most males successfully reproduced for the 1st time at 3 years of age, which is well after their physiological maturity. The few successful young males (i.e., 2 year olds) were likely fast-growing individuals that could successfully hold a territory. The high variance in YBS and antler size for old males at Bogesund, Sweden, suggests that only some males of this age class are able to maintain large antlers and, hence, retain their territories.
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| 28. |
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| 29. |
- Ledin, Anna, et al.
(författare)
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High plasma IgE levels within the Scandinavian wolf population, and its implications for mammalian IgE homeostasis
- 2008
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Ingår i: Molecular Immunology. - : Elsevier BV. - 0161-5890 .- 1872-9142. ; 45:7, s. 1976-1980
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Tidskriftsartikel (refereegranskat)abstract
- Immunoglobulin E (IgE) serves as an important link between innate and adaptive immunity through its ability to bind high affinity receptors on mast cells and basophils. Large differences in IgE levels may here affect this important link, and IgE levels in natural non-domestic animal populations may therefore be very informative concerning the levels of IgE that this system have been balanced against during recent mammalian evolution. However, very few such studies have been performed. Here, we present an analysis of total IgE levels in 65 Scandinavian wolves: 57 free living (wild), and 8 wolves in captivity (Zoo). The 57 wild wolves correspond to approximately 30% of the entire wolf population in Sweden and Norway and thus represent a large fraction of the entire population, making this a unique sample from a wild canine population. The median IgE level in these wolves was 67 μg/ml, which is approximately twice the level seen in domestic dogs and more than 100 times the levels in non-atopic humans. The collected information from domestic and wild populations now indicate that the very low IgE levels observed in man and laboratory rodents are most likely an effect of a life in a relatively parasite free environment, and that total IgE levels under maximally stimulatory (normal) conditions may reach 100-200 μg/ml.
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| 30. |
- Liberg, Benny, et al.
(författare)
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Motor imagery in bipolar depression with slowed movement.
- 2013
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Ingår i: The Journal of nervous and mental disease. - 1539-736X. ; 201:10, s. 885-93
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Tidskriftsartikel (refereegranskat)abstract
- We hypothesized that motor retardation in bipolar depression is mediated by disruption of the pre-executive stages of motor production. We used functional magnetic resonance imaging to investigate neural activity during motor imagery and motor execution to elucidate whether brain regions that mediate planning, preparation, and control of movement are activated differently in subjects with bipolar depression (n = 9) compared with healthy controls (n = 12). We found significant between-group differences. During motor imagery, the patients activated the posterior medial parietal cortex, the posterior cingulate cortex, the premotor cortex, the prefrontal cortex, and the frontal poles more than the controls did. Activation in the brain areas involved in motor selection, planning, and preparation was altered. In addition, limbic and prefrontal regions associated with self-reference and the default mode network were altered during motor imagery in bipolar depression with motor retardation.
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| 31. |
- Liberg, Olof, et al.
(författare)
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Activity patterns of predator and prey: a simultaneous study of GPS-collared wolves and moose
- 2011
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Ingår i: Animal Behaviour. - : Elsevier BV. - 0003-3472 .- 1095-8282. ; 81, s. 423-431
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Tidskriftsartikel (refereegranskat)abstract
- 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 through the study period, and investigated the association in activity patterns between the two species. Wolf activity peaked at dawn. The distance moved per time unit and the linearity of the movement were higher in wolves than in moose, but both species showed a decrease in these variables in June, coinciding with the denning and calving seasons. With the exception of the summer months when the activity of wolves and moose was limited by the raising of offspring, we found no correlation between the temporal activities of the two species. Hence, we did not find support for the hypothesis that the wolves and moose in Scandinavia have adjusted to each other's activity patterns. We discuss the results in light of the relative density of the two species and the intensive human harvest of moose, and hypothesize that synchronicity of predator-prey activity patterns may be ratio dependent. (C) 2010 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
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| 32. |
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| 33. |
- Liberg, Olof, et al.
(författare)
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An updated synthesis on appropriate science-based criteria for "favourable reference population" of the Scandinavian wolf (Canis lupus) population : Assignment from the Swedish Environmental Protection Agency (SEPA)
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report provides an updated synthesis on appropriate science-based criteria for "favourable reference population" FRP for the Scandinavian wolf (Canis lupus) population and present quantitative values on FRP. The assignment was given by the Swedish Environmental Protection Agency to the SKANDULV research group at Grimsö, SLU, Sweden. A thorough review of the ecology and genetics of the wolf population is provided, including measurements of inbreeding depression in the population. Results from earlier MVP analyses of the Scandinavian wolf population are presented, as are former suggestions of FRP or other management goals for the population. A consensus was not possible to achieve among all involved scientist, the results are therefore presented in two different parts. OL, CW, øF, PW and HS suggest that the population value for FRP should be 340 for Scandinavia, and 300 for Sweden. They argue that this Scandinavian sub-population should be connected to a larger meta-population with the minimum size of Ne=500, corresponding to approximately 1700 wolves, and the connection should be minimum one immigrant from the large meta-population to the Scandinavian wolf population per generation. They acknowledge a meta-population that includes also wolves living outside of EU territory, as long as there is the stipulated connectivity. GC evaluated FCS based on a strict interpretation of Habitats Directive informed by previous rulings by the European Court of Justice and documents from the European Commission. He finds that if Sweden cannot include wolves from outside its national territory to fulfill its obligations under the Habitats Directive, FCS will be achieved at 1700 wolves (Ne=500) or at the country carrying capacity. If on the contrary Sweden can include wolves living in a separate population from another country to fulfill its obligations under the Habitats Directive, FCS will be achieved at half the country carrying capacity (preliminarily estimated at 1200/2=600 wolves) or more according to the connectivity naturally achieved. Non EU Member States cannot contribute to this meta-population. There was consensus between all researchers that the target for the population inbreeding coefficient should be 0.2 or lower.
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| 34. |
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| 35. |
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| 36. |
- Liberg, Olof
(författare)
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Decades of population genetic research reveal the need for harmonization of molecular markers: the grey wolf Canis lupus as a case study
- 2016
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Ingår i: Mammal Review. - : Wiley. - 0305-1838 .- 1365-2907. ; 46, s. 44-59
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Forskningsöversikt (refereegranskat)abstract
- 1. Following protection measures implemented since the 1970s, large carnivores are currently increasing in number and returning to areas from which they were absent for decades or even centuries. Monitoring programmes for these species rely extensively on non-invasive sampling and genotyping. However, attempts to connect results of such studies at larger spatial or temporal scales often suffer from the incompatibility of genetic markers implemented by researchers in different laboratories. This is particularly critical for long-distance dispersers, revealing the need for harmonized monitoring schemes that would enable the understanding of gene flow and dispersal dynamics.2. Based on a review of genetic studies on grey wolves Canis lupus from Europe, we provide an overview of the genetic markers currently in use, and identify opportunities and hurdles for studies based on continent-scale datasets.3. Our results highlight an urgent need for harmonization of methods to enable transnational research based on data that have already been collected, and to allow these data to be linked to material collected in the future. We suggest timely standardization of newly developed genotyping approaches, and propose that action is directed towards the establishment of shared single nucleotide polymorphism panels, next-generation sequencing of microsatellites, a common reference sample collection and an online database for data exchange.4. Enhanced cooperation among genetic researchers dealing with large carnivores in consortia would facilitate streamlining of methods, their faster and wider adoption, and production of results at the large spatial scales that ultimately matter for the conservation of these charismatic species.
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| 37. |
- Liberg, Olof, et al.
(författare)
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Effects of migration and selective harvest for the genetic status of the Scandinavian wolf population : A report to the Swedish Environment Protection Agency SEPA (Naturvårdsverket)
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- På uppdrag av Naturvårdsverket har vi beräknat hur inavelskoefficient och släktskap i den skandinaviska vargstammen påverkas av invandring, populationsstorlek och olika jaktstrategier. För beräkningarna av effekter de närmsta två åren av en selektiv jakt, riktad mot de revir med de högsta släktskapskoefficienterna använde vi manuella simuleringar gjorda i Excel, byggda på pedigreedata från det skandinaviska vargprojektet SKANDULV och resultat från Viltskadecenters årliga lägesrapporter. För beräkningar av genetiska effekter på längre sikt, upp till 100 och 300 år, gjorde vi simuleringar utifrån en individbaserad populationsmodell som integrerar demografi med genetik med hjälp av data från den skandinaviska vargstammen. Analysen för effekter de närmsta två åren visade att även utan ytterligare invandring kan man göra vissa kortsiktiga vinster med en selektiv jakt. Med en jakt som tog bort de fem högst rankade vargflockarna enligt deras släktskap med övriga populationen, sänktes inavelskoefficienten F efter två års jakter från dagens nivå på 0,260 till 0,246, och om de 10 högst rankade flockarna togs bort sänktes F till 0,229. Samtidigt visades att högst 9 flockar kan tas bort utan att sänka antalet flockar i populationen till nästa år. Resultaten från simuleringarna av effekter på lång sikt delades upp i effekter på inavelsnivån respektive på hur lång tid det tar att uppnå en viss inavelsnivå. Vid en viss given invandringsfrekvens går inavelskoefficienten F mot en jämviktsnivå, som dock kan ta många år att uppnå. Avgörande för var denna jämviktsnivå kommer att ligga är migrationshastigheten, dvs. hur många invandrare som kommer in per tidsenhet. Vid en invandrare var femte år kommer jämviktsnivån för F att ligga på ungefär 0,22 medan om det kommer in en invandrare vartannat år sjunker nivån till 0,13 och vid en invandrare per år sjunker nivån på F ytterligare till c:a 0,08. Om man reglerar stammen med en selektiv jakt där invandrare och deras avkommor skyddas, förstärker man effekten av invandring avsevärt. Vid t.ex. 1 invandrare per år sänks jämviktsnivån från 0,08 till 0,04 med en sådan selektiv jakt. Detta beror på att invandrarna och deras avkommor blir "effektivare" dvs. de får större genomslag än övriga vargar när de genom skyddet (mot jakten) får högre överlevnad än de senare. Dessa jämviktsnivåer av F är oberoende av populationsstorleken. Vid en viss given invandringshastighet spelar det ingen roll för den slutliga nivån för F om stammen innehåller 200 eller 1000 vargar. Däremot har populationsstorleken betydelse för hur snabbt inavelsnivåerna sjunker ned till sina jämviktslägen. Processen går fortare, ju mindre populationen är. Processen går också fortare genom selektiv jakt där invandrare och deras avkommor skyddas. Den kan dessutom ytterligare påskyndas genom att tillföra några extra obesläktade vargar tidigt i processen i en s.k "stötdos". I tabell 3 jämförs effekterna på tiden det tar för inavelskoefficienten att nå ned från dagens nivå på 0,26 till 0,1 med en invandringshastighet av 1 invandrare per år, men för olika populationsstorlekar, jaktstrategier (slumpad jakt och selektiv jakt) och med eller utan en stötdos på 6 extra vargar de första fem åren. Med en populationsstorlek på 400 vargar tar det med slumpmässig jakt och ingen stötdos 87 år att nå ned till F=0,1. Om populationen istället hållits på 200 djur hade tiden sjunkit till 51 år och med en selektiv jakt hade denna tid minskat ytterligare till 14 år. Om man dessutom hade lagt till stötdosen hade det endast krävts 10 år att nå ned till denna nivå. Slutsatser: 1. Vargstammens genetiska status kan aldrig förbättras på lång sikt genom någon speciell jaktstrategi, tillförsel av obesläktade individer utifrån är nödvändig för en bestående positiv effekt på inavelsnivån och bevarandet av genetisk variation. 2. Förutsatt att det föreligger ett konstant flöde av invandrare till populationen, kan en väl designad selektiv jakt resultera i en reduktion, både av inavelsnivån (F) och den tid som krävs för att uppnå en viss lägre inavelsnivå. 3. Viss temporär förbättring av inavelsnivå kan dock uppnås utan ytterligare invandring. Efter två års jakt riktad mot de 5 resp. 10 av reviren med de högsta släktskapsnivåerna kan den genomsnittliga inavelskoefficienten i stammen minska från 0,260 till 0,246 respektive 0,299. 4. Under förutsättning att givarpopulationen är tillräckligt stor kommer en viss given invandringsfrekvens att leda till ett viss givet jämviktsläge för inavelskoefficienten. 5. Jämviktsläget för inaveln av en viss invandringsfrekvens kan ytterligare sänkas med en selektiv jakt som skydda migranter och deras avkommor, utan att invandringsfrekvensen ändras. Vid t.ex. 1 invandrare per år sänks jämviktsläget från 0,08 till 0,04 med en sådan selektiv jakt. 6. Jämviktsnivån för inavelkoefficienten är oberoende av populationsstorleken. Däremot har populationsstorleken betydelse för hur snabbt inavelsnivåerna sjunker ned till sina jämviktslägen. Ju mindre populationen är desto snabbare går denna process. 7. En selektiv jakt där invandrare och deras avkommor skyddas reducerar även den tid det tar att nå ned till en viss given inavelsnivå. 8. Tiden det tar att nå ned till en viss inavelsnivå kan minskas ytterligare om man tillför ett extra antal vargar utöver den rådande invandringsfrekvensen.
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| 38. |
- Liberg, Olof, et al.
(författare)
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Encounter frequencies between GPS-collared wolves (Canis lupus) and moose (Alces alces) in a Scandinavian wolf territory
- 2009
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Ingår i: Ecological Research. - : Wiley. - 0912-3814 .- 1440-1703. ; 24, s. 547-557
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Tidskriftsartikel (refereegranskat)abstract
- 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 we also found a higher number of close encounters (<500 m) than expected. This suggests that the wolves were actively seeking the individual moose within their territory. Furthermore, the wolves showed a preference for moving on gravel forest roads, which may be used as convenient travel routes when patrolling the territory and seeking areas where the moose are. However, due to the particularly large size of the wolf territory combined with relatively high moose densities, the wolves generally spent a very small proportion of their time inside the home range of each individual moose, and the frequency of encounters between the wolves and any particular moose was very low. We suggest that the high moose:wolf ratio in this large Scandinavian wolf territory compared to that typically occurring in North America, results in a relatively low encounter frequency and a low predation risk for individual moose, as the predation pressure is spread over a high number of prey individuals
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| 39. |
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| 40. |
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| 41. |
- Liberg, Olof, et al.
(författare)
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Monitoring of wolves in Scandinavia
- 2012
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Ingår i: Hystrix, the Italian Journal of Mammalogy. - 0394-1914 .- 1825-5272. ; 23, s. 29-34
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Tidskriftsartikel (refereegranskat)abstract
- The Scandinavian wolf population is jointly monitored by Norwegian and Swedish authorities. Monitoring is made annually. Wolves are classified in different categories. Family groups (>= 3 animals sharing a territory), territorial pairs, other stationary wolves, and vagrants. Also number of reproductions are determined each year, and has the highest priority as national management goals for the wolf population in both countries are expressed as number of reproducing units. Three methods are used in combination. Tracking on snow is the basic method. Around 100 field workers are employed full time or part time to find and follow tracks of wolves during the monitoring season Oct. 1 - Feb 28. The second method is DNA-analysis, mainly based on wolf scats collected during tracking. DNA-analysis help verifying reproductions, identifying newly established pairs, differentiating between neighboring territories and for identifying new immigrants from the Finnish/Russian population. The third method is radio telemetry. 10-20 wolves are equipped with GPS-collars each year, and used for determining of territory extents and differentiating between neighboring territories. All monitoring data are recorded in national databases, and compiled each year in an annual monitoring reports. Annual budget for large carnivore monitoring in the two countries combined in 2011 was approximately 5.8 million Euro, of which approximately 1.5 million was spent on wolves.
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| 42. |
- Liberg, Olof, et al.
(författare)
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Poaching-related disappearance rate of wolves in Sweden was positively related to population size and negatively to legal culling
- 2020
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Ingår i: Biological Conservation. - : Elsevier BV. - 0006-3207 .- 1873-2917. ; 243
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Tidskriftsartikel (refereegranskat)abstract
- Poaching is an important limiting factor for many large carnivore populations worldwide and the effect that legal culling has on poaching rate on wolf (Canis lupus) is debated. We used data linked to population monitoring and research to analyze rate and risk of disappearance without known cause for territorial pair-living wolves (n = 444) in Sweden 2000/01-2016/17. Known mortalities included legal kills (n = 103), natural causes (n = 23), traffic (n = 8) and verified poaching (n = 20) but most (n = 189) wolves disappeared without known cause. Careful evaluation of alternative causes supported the assumption that poaching was the most likely reason for the majority of these disappearances. Disappearance rate was 0.14 for the entire study period, and increased from 0.09 in 2000/01-2009/10 to 0.21 in 2010/11-2016/17, while a Kaplan-Meier analysis on a sub-sample of radio collared wolves (n = 77) gave an average annual poaching rate of 0.12 for the entire study period and 0.10 and 0.18 for the corresponding two sub-periods. Factors affecting disappearance rate were modeled using logistic regression and Cox proportional hazards regression. Population size had a strong positive effect on disappearance rate in both models, whereas legal culling rate had a negative effect, significant only in the Cox model. The combined effect of legal culling rate and disappearance rate during the latter part of our study period has halted population growth. Our results contribute to an increased understanding of two vital drivers predicted to affect poaching rate: population size and legal culling.
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| 43. |
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| 44. |
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| 45. |
- Liberg, Olof, et al.
(författare)
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Rådjuren styr lodjursstammen
- 2011
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Ingår i: Svensk jakt. - 0039-6583. ; , s. 26-27
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 46. |
- Liberg, Olof, et al.
(författare)
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Shoot, shovel and shut up: cryptic poaching slows restoration of a large carnivore in Europe
- 2012
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Ingår i: Proceedings of the Royal Society B: Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 279, s. 910-915
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Tidskriftsartikel (refereegranskat)abstract
- Poaching is a widespread and well-appreciated problem for the conservation of many threatened species. Because poaching is illegal, there is strong incentive for poachers to conceal their activities, and consequently, little data on the effects of poaching on population dynamics are available. Quantifying poaching mortality should be a required knowledge when developing conservation plans for endangered species but is hampered by methodological challenges. We show that rigorous estimates of the effects of poaching relative to other sources of mortality can be obtained with a hierarchical state space model combined with multiple sources of data. Using the Scandinavian wolf (Canis lupus) population as an illustrative example, we show that poaching accounted for approximately half of total mortality and more than two-thirds of total poaching remained undetected by conventional methods, a source of mortality we term as 'cryptic poaching'. Our simulations suggest that without poaching during the past decade, the population would have been almost four times as large in 2009. Such a severe impact of poaching on population recovery may be widespread among large carnivores. We believe that conservation strategies for large carnivores considering only observed data may not be adequate and should be revised by including and quantifying cryptic poaching.
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| 47. |
- Liberg, Olof, et al.
(författare)
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Så kan vargstammen räddas
- 2010
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Ingår i: Dagens nyheter. - 1101-2447.
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 48. |
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| 49. |
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| 50. |
- Liberg, Olof, et al.
(författare)
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Ungulates and their management in Sweden
- 2010
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Ingår i: European Ungulates and their Management in the 21st century. - 9780521760614 ; , s. 37-70
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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