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Population dynamics of tundra-living grey-sided voles
Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi och geovetenskap.
2003 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

This thesis deals with the dynamics of tundra living voles with emphasis on the most common one, the grey-sided vole (Clethrionomys rufocanus). The tundra area chosen for the study was Finnmarksvidda, a vast flatland in northernmost Norway. All small mammal herbivores in the area showed dramatic fluctuations, and field experiment were conducted in order to elucidate these density fluctuations. The specific subjects addressed included: 1/ Temporal and spatial appearance of density fluctuations of voles and lemmings in the area, 2/ The generality of the density patterns observed, 3/ The impact of predation by vole predators during summertime, 4/ The impact of grey-sided vole grazing on food plants of different preference in a predator free environment, in the presence and absence of extra food, and 5/ The impact of food availability on density and demography of grey-sided voles in a predator free environment.

The results achieved showed that voles in the slope and lowland had cyclic density fluctuations with 5 years duration. The cycles consisted of four phases: an increase phase, a peak phase, a decline phase and a crash phase. In the unproductive lowland and on the moderately productive slope, small pockets of productive habitats seemed to work as “triggers” for the cycles. The lemming fluctuations in the upper plateau (separated from the slope by a steep zone of boulders) differed markedly from the vole patterns in the lowland.

Only two lemming peaks were recorded in twenty years. Both peaks had very short increase phases, a knife-sharppeak phase and no decline phase before the crash. A comparison between our results and lemming and vole populations from two other areas in Fennoscandia revealed the same difference in fluctuation pattern between lemmings and voles as seen in our area. This results suggests that lemmings in barren tundra highlands and voles in slightly more productive tundra lowlands are regulated by different mechanisms.

The exclusion of vole predators from vole populations during summertime led to increase in overall vole density. Densities of the clumsy field vole (Microtus agrestis) and juveniles of all species showed the strongest positive effects of the exclusion.

An experiment analysing the effects of food availability was conducted in islands in a large lake where grey-sided voles were introduced to predator free islands . Supplemental food was given to the voles in two unproductive, and two productive islands. Two unproductive and two productive islands were used as reference islands. The density of voles and the vole weight were higher in both the islands with supplemental food and those with high natural productivity. Increased vole density did not significantly increase grazing damage to plants. The cyclic density pattern of the voles in the nearby mainland (that harboured resident vole specialist predators as stoat and weasel) showed little resemblance to the seasonal fluctuations found in the islands (devoid of resident vole specialist predators). This result suggested that predation by stoat and weasel on grey-sided vole populations may cause the cyclic vole fluctuations seen in the area.

sted, utgiver, år, opplag, sider
2003. , s. 38
Emneord [en]
Ecology, Population dynamics, Tundra, Grey-sided vole, Cycles, Vole specialist predators
Emneord [sv]
Ekologi
HSV kategori
Forskningsprogram
zooekologi
Identifikatorer
URN: urn:nbn:se:umu:diva-187ISBN: 91-7305-300-7 (tryckt)OAI: oai:DiVA.org:umu-187DiVA, id: diva2:142263
Disputas
2003-06-16, Stora hörsalen, KBC, Umeå, 08:15
Opponent
Veileder
Tilgjengelig fra: 2004-01-30 Laget: 2004-01-30bibliografisk kontrollert
Delarbeid
1. Long-term dynamics of voles and lemmings at the timberline and above the willow limit as a test of hypothesis on trophic interactions
Åpne denne publikasjonen i ny fane eller vindu >>Long-term dynamics of voles and lemmings at the timberline and above the willow limit as a test of hypothesis on trophic interactions
2001 Inngår i: Ecography, ISSN 0906-7590, Vol. 24, s. 555-568Artikkel i tidsskrift (Fagfellevurdert) Published
Identifikatorer
urn:nbn:se:umu:diva-3519 (URN)
Tilgjengelig fra: 2004-01-30 Laget: 2004-01-30bibliografisk kontrollert
2. Are lemmings prey or predators?
Åpne denne publikasjonen i ny fane eller vindu >>Are lemmings prey or predators?
Vise andre…
2000 Inngår i: Nature, ISSN 0028-0836, Vol. 405, s. 562-565Artikkel i tidsskrift (Fagfellevurdert) Published
Identifikatorer
urn:nbn:se:umu:diva-3520 (URN)
Tilgjengelig fra: 2004-01-30 Laget: 2004-01-30bibliografisk kontrollert
3. The impact of short-term predator removal on vole dynamics in a subarctic-alpine habitat complex
Åpne denne publikasjonen i ny fane eller vindu >>The impact of short-term predator removal on vole dynamics in a subarctic-alpine habitat complex
Inngår i: Oikos, ISSN 0030-1299Artikkel i tidsskrift (Fagfellevurdert) Submitted
Identifikatorer
urn:nbn:se:umu:diva-3521 (URN)
Tilgjengelig fra: 2004-01-30 Laget: 2004-01-30bibliografisk kontrollert
4. Mechanisms of apparent competition in seasonal environments: an example with vole herbivory
Åpne denne publikasjonen i ny fane eller vindu >>Mechanisms of apparent competition in seasonal environments: an example with vole herbivory
1997 Inngår i: Oikos, ISSN 0030-1299, Vol. 80, s. 276-288Artikkel i tidsskrift (Fagfellevurdert) Published
Identifikatorer
urn:nbn:se:umu:diva-3522 (URN)
Tilgjengelig fra: 2004-01-30 Laget: 2004-01-30bibliografisk kontrollert
5. Effects of spatial isolation, habitat quality, and supplemental food for population dynamics of the grey-sided vole, Clethrionomys rufocanus
Åpne denne publikasjonen i ny fane eller vindu >>Effects of spatial isolation, habitat quality, and supplemental food for population dynamics of the grey-sided vole, Clethrionomys rufocanus
Manuskript (Annet vitenskapelig)
Identifikatorer
urn:nbn:se:umu:diva-3523 (URN)
Tilgjengelig fra: 2004-01-30 Laget: 2004-01-30 Sist oppdatert: 2010-01-13bibliografisk kontrollert

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