Ruffino, Lise, Hartley, Susan E orcid.org/0000-0002-5117-687X, DeGabriel, Jane L. et al. (1 more author) (2018) Population-level manipulations of field vole densities induce subsequent changes in plant quality but no impacts on vole demography. Ecology and Evolution. ISSN 2045-7758
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 defences 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 one 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 defences 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 defences 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 lab-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.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2018 The Authors. |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Biology (York) |
Depositing User: | Pure (York) |
Date Deposited: | 12 Apr 2018 14:20 |
Last Modified: | 16 Oct 2024 14:39 |
Published Version: | https://doi.org/10.1002/ece3.4204 |
Status: | Published |
Refereed: | Yes |
Identification Number: | 10.1002/ece3.4204 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:129536 |
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