Population-level manipulations of field vole densities induce subsequent changes in plant quality but no impacts on vole demography

Lise Ruffino, Susan E. Hartley, Jane L. Degabriel, Xavier Lambin* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticle

2 Citations (Scopus)
6 Downloads (Pure)

Abstract

Grazing-induced changes in plant quality have been suggested to drive the negative delayed density dependence exhibited by many herbivore species, but little field evidence exists to support this hypothesis. We tested a key premise of the hypothesis that reciprocal feedback between vole grazing pressure and the induction of anti-herbivore silicon defenses in grasses drives observed population cycles in a large-scale field experiment in northern England. We repeatedly reduced population densities of field voles (Microtus agrestis) on replicated 1-ha grassland plots at Kielder Forest, northern England, over a period of 1 year. Subsequently, we tested for the impact of past density on vole life history traits in spring, and whether these effects were driven by induced silicon defenses in the voles' major over-winter food, the grass Deschampsia caespitosa. After several months of density manipulation, leaf silicon concentrations diverged and averaged 22% lower on sites where vole density had been reduced, but this difference did not persist beyond the period of the density manipulations. There were no significant effects of our density manipulations on vole body mass, spring population growth rate, or mean date for the onset of spring reproduction the following year. These findings show that grazing by field voles does induce increased silicon defenses in grasses at a landscape scale. However, at the vole densities encountered, levels of plant damage appear to be below those needed to induce changes in silicon levels large and persistent enough to affect vole performance, confirming the threshold effects we have previously observed in laboratory-based studies. Our findings do not support the plant quality hypothesis for observed vole population cycles in northern England, at least over the range of vole densities that now prevail here.

Original languageEnglish
Pages (from-to)7752-7762
Number of pages11
JournalEcology and Evolution
Volume8
Issue number16
Early online date13 Jul 2018
DOIs
Publication statusPublished - Aug 2018

Fingerprint

demography
silicon
population cycle
grass
herbivore
England
grazing
grasses
grazing pressure
density dependence
voles
herbivores
life history trait
Deschampsia cespitosa
body mass
Microtus agrestis
population growth
population density
grassland
plant damage

Keywords

  • Density-dependence
  • Induced defense
  • Microtus agrestis
  • Population cycles
  • Silicon

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology
  • Nature and Landscape Conservation

Cite this

Population-level manipulations of field vole densities induce subsequent changes in plant quality but no impacts on vole demography. / Ruffino, Lise; Hartley, Susan E.; Degabriel, Jane L.; Lambin, Xavier (Corresponding Author).

In: Ecology and Evolution, Vol. 8, No. 16, 08.2018, p. 7752-7762.

Research output: Contribution to journalArticle

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