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Circumpolar variation in anti-browsing defense in tundra dwarf birches
Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
2017 (English)Independent thesis Advanced level (degree of Master (Two Years)), 40 credits / 60 HE creditsStudent thesis
Abstract [en]

The shrub encroachment (shrubification) currently happening in tundra ecosystems can result in increased greenhouse gas emissions. Shrubification is in turn generally explained to be driven by increased temperature, but there is regional variation in shrub encroachment that cannot be solely explained by climate. Instead, herbivory is proposed as a key factor since browsing has been shown to regulate density of shrubs in the tundra. Furthermore, regional variation in anti-browsing defense, i.e. various deterrent and/or toxic compounds, has been hypothesized to control the herbivory pressure. Dwarf birches are present and often dominant throughout the low arctic. They can be divided into two functional groups based on their anti-browsing defense, i.e. resinous and non-resinous birches. This study investigated the variation in anti-browsing defense within and among different taxa of dwarf birches and the two functional groups. We also examined if these differences in anti-browsing defense affects the level of invertebrate damage in dwarf birch. We found that although there were clear differences in terpenes between resinous and non-resinous shrubs, neither functional groups nor taxa are sufficient to understand the circumpolar variation in defense compounds. Moreover, the variation in chemical anti-browsing defense had no clear effect on the level of invertebrate damage, indicating that many other factors than food quality regulate the abundance and importance of herbivores. This study does, for the first time, reveal the circumpolar variation in anti-browsing defense in dwarf birches, which will be vital for a mechanistic understanding of the greening of the arctic in the future.

Place, publisher, year, edition, pages
2017. , 13 p.
Keyword [en]
Anti-browsing defense, dwarf birch, herbivory, plant secondary metabolites, tundra
National Category
Natural Sciences
Identifiers
URN: urn:nbn:se:umu:diva-130407OAI: oai:DiVA.org:umu-130407DiVA: diva2:1066729
Educational program
Master's Programme in Ecology
Supervisors
Examiners
Available from: 2017-01-19 Created: 2017-01-19Bibliographically approved

Open Access in DiVA

fulltext(978 kB)64 downloads
File information
File name FULLTEXT01.pdfFile size 978 kBChecksum SHA-512
f355b552c40c8bab77c1adbbbd5ba99eeeb0af92b887b3aac85e5a702ea9710626a98a013e90d09731666d6ce5f733ba1732ce9688c1c41bd4bc16105dc39646
Type fulltextMimetype application/pdf

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Department of Ecology and Environmental Sciences
Natural Sciences

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CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf