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Cyclic voles and Puumala hantavirus in a changing boreal landscape

Magnusson, Magnus (2015). Cyclic voles and Puumala hantavirus in a changing boreal landscape. Diss. (sammanfattning/summary) Umeå : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2015:4
ISBN 978-91-576-8206-2
eISBN 978-91-576-8207-9
[Doctoral thesis]

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Abstract

Land-use change is causing extinction of species globally, while also increasing the risk of disease exposure to humans through augmented interactions with wildlife, when humans live and work in manipulated ecosystems or when animals seek shelter/refuge in man-made infrastructure.

Forestry is one such activity, which is continually altering forest structure worldwide, causing habitat loss for many specialized forest species. This study investigates the population ecology of three cyclic vole species, Myodes rufocanus, Myodes glareolus and Microtus agrestis, in relation to intensive forestry in northern Sweden. M. glareolus is also the natural reservoir of Puumala hantavirus (PUUV) which is important from a public health perspective since PUUV causes nephropathia epidemica in humans. M. rufocanus and M. agrestis declined substantially in density and distribution during the 1970-80s while M. glareolus only marginally declined and is still the most common species in the region.

The decline of M. rufocanus was related to habitat loss. The cumulated impact from long-term clear-cutting explained local extinctions of M. rufocanus. The species is also dependent on maintained connectivity between old forest and shelter-providing stone fields. In contrast, local extinction of M. agrestis was not related to forestry, suggesting action of another strong driver. M. agrestis re-colonized most of the study area during 2010-2011, two years that were characterised by cold winters and a thick snow cover, suggesting a climatic driver in this case. Occurrence of PUUV infected M. glareolus was negatively related to the impact of long-term clear-cutting in the surrounding landscape. PUUV infected M. glareolus survived during low density periods of the vole cycle in old forests.

In summary, the main driver of the decline in density and distribution of M. rufocanus appeared to be intensive forestry. PUUV infection dynamics also appeared to be related to forestry. Since land-use changes and climate changes have coincided in Fennoscandian forests, I suggest that future studies should focus on estimating the relative impact of these two factors on pathogen and vole population dynamics.

Authors/Creators:Magnusson, Magnus
Title:Cyclic voles and Puumala hantavirus in a changing boreal landscape
Alternative abstract:
LanguageAbstract
Swedish

Intensivt skogsbruk har påverkat de flesta av världens skogsekosystem och lett till biotopförluster för många specialiserade arter. I norra Sverige har kalhyggesbruket varit den dominerade skogsbruksmetoden sedan 1950-talet. Gamla, flerskiktade skogar har ersatts av unga, enkelskiktade monokulturer. I den här avhandlingen har tre cykliska sorkarter studerats i relation till kalhyggesbruket. Fokus ligger på gråsiding (Myodes rufocanus), men även åkersork (Microtus agrestis) och skogssork (Myodes glareolus) har studerats. Gråsiding minskade markant i täthet och utbredning under 1970- och 1980-talen. Åkersork minskade också medan skogssork, värddjur för Puumala hantavirus (PUUV) som orsakar sorkfeber (nephropathia epidemica) hos människan, inte hade en lika markant nergång som gråsiding och åkersork.

Gråsiding föredrog lokalt gamla tallskogar och blockfält. På landskapsnivå var konnektivitet av gammal skog, storlek på fläckar av gammal skog och närhet till blockfält viktigt. Den sammanlagda mängden kalhyggen sedan 1970-talet i olika landskap hade en direkt koppling till gråsidingens minskning. Åkersorkens nergång kunde inte förklaras av kalhyggesbruket men istället verkar vinterförhållanden vara viktiga. Åkersorken återkoloniserade stora delar av undersökningsområdet under 2010-2011, två år som karakteriserades av snörika och kalla vintrar.

Den sammanlagda mängden kalhyggen i det omgivande landskapet var också negativt kopplad till förekomst av PUUV-infekterade skogssorkar på våren. Infekterade sorkar överlevde bottenfaser mellan cykler i gamla skogar medan myrar visade sig vara dåliga biotoper för både infekterade och icke infekterade skogssorkar.

Sammanfattningsvis konstateras att både den rumsliga och tidsmässiga variationen i täthet och utbredning av gråsiding och PUUV-infekterade skogssorkar påverkas av det intensiva kalhyggesbruket. Landskapsförändringarna orsakade av intensivt kalhyggesbruk har i den boreala skogsregionen skett parallellt med en period av varmare vintrar. Jag föreslår att framtida studier bör fokusera på att undersöka dessa två faktorers relativa påverkan på populationsdynamiken hos PUUV-infekterade skogssorkar, gråsiding och åkersork.

Series/Journal:Acta Universitatis agriculturae Sueciae (1652-6880)
Year of publishing :2015
Depositing date:10 December 2014
Volume:2015:4
Number of Pages:50
Papers/manuscripts:
NumberReferences
I.Ecke, F., Magnusson, M., Hörnfeldt, B. (2013). Spatiotemporal changes in the landscape structure of forests in northern Sweden. Scandinavian Journal of Forest Research 28, 651-667.
II.Magnusson, M., Bergsten, A., Ecke, F., Bodin, Ö., Bodin, L., Hörnfeldt, B. (2013). Predicting grey-sided vole occurrence in northern Sweden at multiple spatial scales. Ecology and Evolution 3, 4365-4376.
III.Magnusson, M., Ecke, F., Khalil, H., Olsson, G., Evander, M., Niklasson, B., Hörnfeldt, B. (submitted). Spatial and temporal variation of hantavirus infection in managed forest landscapes.
IV.Magnusson, M., Hörnfeldt, B., Ecke, F. (manuscript). Evidence for different drivers behind dampening of vole cycles across Europe.
Place of Publication:Umeå
Publisher:Institutionen för vilt, fisk och miljö, Sveriges lantbruksuniversitet
ISBN for printed version:978-91-576-8206-2
ISBN for electronic version:978-91-576-8207-9
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:L Animal production > L20 Animal ecology
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Zoology
(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Ecology
Agrovoc terms:voles, microtus, hantavirus, human diseases, disease transmission, boreal forests, clear felling, climatic factors, habitats, animal population, population ecology, endangered species, sweden
Keywords:Boreal forest, Clear-cuts, Connectivity, Forestry, Habitat loss, Myodes rufocanus, Myodes glareolus, Microtus agrestis, Puumala Hantavirus, Spatiotemporal changes
URN:NBN:urn:nbn:se:slu:epsilon-e-2258
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-2258
ID Code:11698
Faculty:S - Faculty of Forest Sciences
Department:(S) > Dept. of Wildlife, Fish and Environmental Studies
External funders:Helge Ax:sson Johnsson Foundation and Stiftelsen Oscar och Lili Lamms minne
Deposited By: Mr Magnus Magnusson
Deposited On:11 Dec 2014 10:27
Metadata Last Modified:14 Dec 2014 19:31

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