| 1. |
- Angerbjörn, Anders, et al.
(author)
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Carnivore conservation in practice : replicatedmanagement actions on a large spatial scale
- 2013
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In: Journal of Applied Ecology. - : Wiley. - 0021-8901 .- 1365-2664. ; 50:1, s. 59-67
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Journal article (peer-reviewed)abstract
- More than a quarter of the world’s carnivores are threatened, often due to multiple andcomplex causes. Considerable research efforts are devoted to resolving the mechanisms behindthese threats in order to provide a basis for relevant conservation actions. However, evenwhen the underlying mechanisms are known, specific actions aimed at direct support for carnivoresare difficult to implement and evaluate at efficient spatial and temporal scales.2. We report on a 30-year inventory of the critically endangered Fennoscandian arctic foxVulpes lagopus L., including yearly surveys of 600 fox dens covering 21 000 km2. These surveysshowed that the population was close to extinction in 2000, with 40–60 adult animalsleft. However, the population subsequently showed a fourfold increase in size.3. During this time period, conservation actions through supplementary feeding and predatorremoval were implemented in several regions across Scandinavia, encompassing 79% of thearea. To evaluate these actions, we examined the effect of supplemental winter feeding andred fox control applied at different intensities in 10 regions. A path analysis indicated that47% of the explained variation in population productivity could be attributed to lemmingabundance, whereas winter feeding had a 29% effect and red fox control a 20% effect.4. This confirms that arctic foxes are highly dependent on lemming population fluctuationsbut also shows that red foxes severely impact the viability of arctic foxes. This study also highlightsthe importance of implementing conservation actions on extensive spatial and temporalscales, with geographically dispersed actions to scientifically evaluate the effects. We note thatpopulation recovery was only seen in regions with a high intensity of management actions.5. Synthesis and applications. The present study demonstrates that carnivore populationdeclines may be reversed through extensive actions that target specific threats. Fennoscandianarctic fox is still endangered, due to low population connectivity and expected climate impactson the distribution and dynamics of lemmings and red foxes. Climate warming is expected tocontribute to both more irregular lemming dynamics and red fox appearance in tundra areas;however, the effects of climate change can be mitigated through intensive managementactions such as supplemental feeding and red fox control.
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| 2. |
- Elmhagen, Bodil, et al.
(author)
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Homage to Hersteinsson and Macdonald : climate warming and resource subsidies cause red fox range expansion and Arctic fox decline
- 2017
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In: Polar Research. - : Norwegian Polar Institute. - 0800-0395 .- 1751-8369. ; 36:suppl. 1
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Research review (peer-reviewed)abstract
- Climate change can have a marked effect on the distribution and abundance of some species, as well as their interspecific interactions. In 1992, before ecological effects of anthropogenic climate change had developed into a topical research field, Hersteinsson and Macdonald published a seminal paper hypothesizing that the northern distribution limit of the red fox (Vulpes vulpes) is determined by food availability and ultimately climate, while the southern distribution limit of the Arctic fox (Vulpes lagopus) is determined by interspecific competition with the larger red fox. This hypothesis has inspired extensive research in several parts of the circumpolar distribution range of the Arctic fox. Over the past 25 years, it was shown that red foxes can exclude Arctic foxes from dens, space and food resources, and that red foxes kill and sometimes consume Arctic foxes. When the red fox increases to ecologically effective densities, it can cause Arctic fox decline, extirpation and range contraction, while conservation actions involving red fox culling can lead to Arctic fox recovery. Red fox advance in productive tundra, concurrent with Arctic fox retreat from this habitat, support the original hypothesis that climate warming will alter the geographical ranges of the species. However, recent studies show that anthropogenic subsidies also drive red fox advance, allowing red fox establishment north of its climate-imposed distribution limit. We conclude that synergies between anthropogenic subsidies and climate warming will speed up Arctic ecosystem change, allowing mobile species to establish and thrive in human-provided refugia, with potential spill-over effects in surrounding ecosystems.
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| 3. |
- Lehikoinen, Aleksi, et al.
(author)
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The impact of weather and the phase of the rodent cycle on breeding populations of waterbirds in Finnish Lapland
- 2016
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In: Ornis Fennica. - 0030-5685. ; 93:1, s. 31-46
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Journal article (peer-reviewed)abstract
- Climate change may affect bird populations both directly by changing the weather conditions, and indirectly through changes in the food chain. While both theoretical and empirical studies have shown climate change having drastic impacts on polar areas, its consequences on Arctic bird species are still poorly known. Here we investigated how weather and changes in predator-prey interactions affected the annual growth rates of sub-Arctic birds by monitoring the breeding numbers of three duck and seven wader species in the alpine tundra of Finnish Lapland during 2005-2015 (except for 2006). We hypothesized that growth rates of waterbirds would be positively associated with warm and dry weather due to improved reproductive success. Furthermore, we tested the hypothesis that water-birds have a higher reproductive success during the cyclic rodent peaks, when predators mainly prey on rodents, than during the decline and low phases of the cycle, when predation pressure towards waterbirds increases. Results showed that population growth rates of breeding ducks were negatively associated with the sum of rainfall in the previous year. In waders, growth rates were positively associated with the phase of the rodent cycle in the same year. Our results emphasize the importance of monitoring Arctic bird populations on their breeding areas to explore what the consequences of climate change might be for breeding waterbirds by linking the effects of both weather and rodent abundance.
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| 4. |
- Voutilainen, Liina, et al.
(author)
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Life-long shedding of Puumala hantavirus in wild bank voles (Myodes glareolus)
- 2015
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In: Journal of General Virology. - : Society for General Microbiology. - 0022-1317 .- 1465-2099. ; 96:6, s. 1238-1247
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Journal article (peer-reviewed)abstract
- The knowledge of viral shedding patterns and viraemia in the reservoir host species is a key factorin assessing the human risk of zoonotic viruses. The shedding of hantaviruses (familyBunyaviridae) by their host rodents has widely been studied experimentally, but rarely in naturalsettings. Here we present the dynamics of Puumala hantavirus (PUUV) shedding and viraemia innaturally infected wild bank voles (Myodes glareolus). In a monthly capture–mark–recapturestudy, we analysed 18 bank voles for the presence and relative quantity of PUUV RNA in theexcreta and blood from 2 months before up to 8 months after seroconversion. The proportion ofanimals shedding PUUV RNA in saliva, urine and faeces peaked during the first month afterseroconversion, but continued throughout the study period with only a slight decline. The quantityof shed PUUV in reverse transcription quantitative PCR (RT-qPCR) positive excreta was constantover time. In blood, PUUV RNA was present for up to 7 months but both the probability of viraemiaand the virus load declined with time. Our findings contradict the current view of a decline in virusshedding after the acute phase and a short viraemic period in hantavirus infection – anassumption widely adopted in current epidemiological models. We suggest the life-long sheddingas a means of hantaviruses to survive over host population bottlenecks, and to disperse infragmented habitats where local host and/or virus populations face temporary extinctions. Ourresults indicate that the kinetics of pathogens in wild hosts may differ considerably from thoseobserved in laboratory settings.
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