Plant-herbivore interactions are well studied, and many herbivore induced responses, such as plant defences, are well characterized. How these induced responses affects other herbivores is not likewise explored, even though they can link herbivores from different life-stages, guilds or even phyla and have effects on both life history and population traits of that herbivore. Granting that most plants are subjected to herbivory by more than one species of herbivore, it is important to consider how responses induced by one herbivore might affect others, and how plant growth might be affected. Not least because the combined effects of several herbivores on the plants may not be additive.
My research is focused on plant-mediated interactions between herbivores. I’m looking at how browsing by large ungulates (such as moose) indirectly affects insect herbivores. I investigate both the effect of browsing on single trees and the mediated effect it has on insects but also the effect browsing has on a forest stand and how that affects abundance and performance of herbivorous insects as well as their natural enemies. I aim to study how induced responses, such as changes in needle nutrient content, affects the performance of the European Pine Sawfly (Neodiprion sertifer) and I hope to link this to sawfly population dynamics using modelling. The project will also investigate the effects on tree growth from the attack of multiple herbivores.
1. How is sawfly performance affected when feeding on ungulate-browsed trees?
2. Is there a difference in herbivore abundance/damage on browsed vs. non-browsed trees?
3. How does changes in plant quality, as a result of browsing, affect sawfly population dynamics?
4. How does changes in stand structure and composition, as a result of browsing, affect predation of herbivores by natural enemies?
5. How is tree growth affected by herbivory from several herbivores (ungulates and insects)?
I address these questions using field experiments in young pine stands in Swedish production forests.
European Pine Sawfly (Neodiprion sertifer)
Moose (Alces alces)
Scots Pine (Pinus sylvestris)
Floristics and entomology 2017, 2018, 2019, 2020
Ecological botany 2017
Conservation biology 2017, 2018
Diversity of organisms 2017
Forest Ecology 2019, 2020
Ecology and management of diseases and pests of forest trees 2017, 2019
Lars Edenius, Department of Wildlife, Fish and Environmental Studies, SLU Umeå.
Jonathan Gershenzon and Axel Schmidt, Max Planck Institute for Chemical Ecology, Jena Germany
I've recently been involved as a co-supervisor for Stephanie Jonsson's Master's thesis on the effect of dead wood on arthropod predator diversity and predation rate of herbivorous insects.
Nordkvist M, Klapwijk MJ, Edenius L, Gershenzon J, Schmidt A & Björkman C. 2019. Trait‐mediated indirect interactions: Moose browsing increases sawfly fecundity through plant‐induced responses. Ecology and Evolution 9:10615-10629. https://doi.org/10.1002/ece3.5581
Nordkvist M, Klapwijk MJ, Edenius L, & Björkman C. 2020. Interacting effects of insect and ungulate herbivory on Scots pine growth. Scientific Reports 10:22341. https://doi.org/10.1038/s41598-020-79346-3
Nordkvist, M. 2020. Interactions between ungulates and forest insects. PhD-thesis. https://pub.epsilon.slu.se/17662/
Nordkvist M, Björkman C & Klapwijk MJ. 2021. Plant Mediated Interactions: Lower Sawfly Survival on Pines Previously Browsed by Moose. Frontiers in Ecology and Evolution. https://doi.org/10.3389/fevo.2021.666069