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Predators in low arctic tundra and their impact on community structure and dynamics
Umeå universitet, Teknisk-naturvetenskaplig fakultet, Ekologi och geovetenskap.
2004 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

The abundance of predators and their impact on ecosystem dynamics is a vividly discussed topic in current ecology. In my studies, incorporating field observations, field experiments and theoretical modeling, I explored the importance of predators and predation in a low arctic tundra ecosystem in northern Norway. This involved observing the abundance and spatial activity of predators (raptors and small mustelids); manipulating the abundance of predators (spiders and birds) in an arthropod community; and exploring the theoretical consequences of intraguild predation on the coexistence among predators.

The results show that predation is important both in the arthropod assemblage and, depending on the productivity of the community, in the vertebrate assemblage. In arthropod communities predators are at least as abundant as their prey, whereas in the vertebrate part of ecosystem, predators are substantially less abundant than their prey. Still, in both cases predators had strong impact on their prey, influencing the abundance of prey and the species composition of prey assemblages. The impact of predation cascaded to the plant community both in the reticulate and complex arthropod food web and in the linear food chain-like vertebrate community. In the vertebrate-based community we could even observe the long time scale effect on plant community composition.

Within the predator community, exploitation competition and intraguild predation were the structuring forces. As the arthropod communities consist of predators with different sizes, intraguild predation is an energetically important interaction for top predators. As a consequence, they reduce the abundance of intermediate predators and the impact of intermediate predators on other prey groups. Moreover, being supported by intermediate predators, top predators can have stronger impact themselves on other prey groups.

In vertebrate communities, intraguild predation seems to be unimportant as energetic link, instead it manifests as an extreme version of interference competition. Therefore intraguild predation reduces the likelihood of coexistence, as it is due limited prey diversity and intense exploitative competition already precarious in the low arctic tundra.

In conclusion, predators have strong impact on their prey, especially in the more productive parts of the low arctic tundra. This applies even to the food webs with complex and reticulate structure, and these effects carry through the community both in the short time scale of population growth and on the long time scale of population generations.

Ort, förlag, år, upplaga, sidor
Umeå: Ekologi och geovetenskap , 2004. , s. 40
Nyckelord [en]
Ecology, arthropods, coexistence, community dynamics, competition, food webs, hypothesis of exploitation ecosystems, intraguild predation, small mustelids, trophic cascades
Nyckelord [sv]
Ekologi
Nationell ämneskategori
Ekologi
Forskningsämne
zooekologi
Identifikatorer
URN: urn:nbn:se:umu:diva-354ISBN: 91-7305-696-0 (tryckt)OAI: oai:DiVA.org:umu-354DiVA, id: diva2:143209
Disputation
2004-12-03, Stora Hörsalen (KB3 B1), KBC, Umeå, 09:00
Opponent
Handledare
Tillgänglig från: 2004-11-09 Skapad: 2004-11-09Bibliografiskt granskad
Delarbeten
1. Outlines of food webs in a low arctic tundra landscape in relation to three theories on trophic dynamics
Öppna denna publikation i ny flik eller fönster >>Outlines of food webs in a low arctic tundra landscape in relation to three theories on trophic dynamics
Visa övriga...
1997 Ingår i: Multitrophic interactions in terrestrial systems, 1997, s. 351-373Kapitel i bok, del av antologi (Övrigt vetenskapligt) Published
Identifikatorer
urn:nbn:se:umu:diva-4204 (URN)0-86542-767-4 (ISBN)
Tillgänglig från: 2004-11-09 Skapad: 2004-11-09Bibliografiskt granskad
2. Biomass patterns in European tundra as a test of hypotheses on trophic dynamics
Öppna denna publikation i ny flik eller fönster >>Biomass patterns in European tundra as a test of hypotheses on trophic dynamics
Visa övriga...
Manuskript (Övrigt vetenskapligt)
Identifikatorer
urn:nbn:se:umu:diva-4205 (URN)
Tillgänglig från: 2004-11-09 Skapad: 2004-11-09 Senast uppdaterad: 2010-01-13Bibliografiskt granskad
3. Habitat selection of coexisting competitors: a study of small mustelids in northern Norway
Öppna denna publikation i ny flik eller fönster >>Habitat selection of coexisting competitors: a study of small mustelids in northern Norway
2003 Ingår i: Evolutionary Ecology, ISSN 0269-7653, Vol. 17, nr 4, s. 371-392Artikel i tidskrift (Refereegranskat) Published
Identifikatorer
urn:nbn:se:umu:diva-4206 (URN)
Tillgänglig från: 2004-11-09 Skapad: 2004-11-09Bibliografiskt granskad
4. Intraguild predation and coexistence in vertebrate predators
Öppna denna publikation i ny flik eller fönster >>Intraguild predation and coexistence in vertebrate predators
Manuskript (Övrigt vetenskapligt)
Identifikatorer
urn:nbn:se:umu:diva-4207 (URN)
Tillgänglig från: 2004-11-09 Skapad: 2004-11-09 Senast uppdaterad: 2010-01-13Bibliografiskt granskad
5. Predation structures the low arctic tundra arthropod community
Öppna denna publikation i ny flik eller fönster >>Predation structures the low arctic tundra arthropod community
Manuskript (Övrigt vetenskapligt)
Identifikatorer
urn:nbn:se:umu:diva-4208 (URN)
Tillgänglig från: 2004-11-09 Skapad: 2004-11-09 Senast uppdaterad: 2010-01-13Bibliografiskt granskad

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