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Research article - Peer-reviewed, 2023

The relationship between moose browsing, habitat structure and predation pressure on insect herbivores

Nordkvist, Michelle; Klapwijk, Maartje J.; Barets, Sabine; Bjorkman, Christer


Grazing and browsing by large ungulates can have a strong effect on habitat composition and structure. Associated effects can be reduction in the abundance of palatable tree species and alter understory properties, thereby affecting habitat complexity. Changes in habitat structure and complexity can in turn affect arthropod predation pressure, as arthropod predators are strongly influenced by habitat characteristics. This may be increasingly important in production forests, as such systems are often more vulnerable to disturbances such as pest insects. However, studies exploring this indirect link between ungulates and predation rate are sparse. We explore this link through the comparison of fenced plots excluding ungulates (for four years) with associated control plots replicated in 16 forest stands covering a large geographical area. We measured vegetation characteristics to assess the effect of exclusion on habitat structure. We used plasticine models to compare predation rates in fenced and control plots on pine trees. In addition, we sampled herbivorous insects to explore the potential relationship between predation and herbivore abundance. We could only demonstrate a weak effect of browser exclusion on habitat structure, suggesting that the time of exclusion was too short to cause a vegetation response. In terms of arthropod predation, we found that predation was positively affected by understory cover, but not related to herbivore abundance. Understory properties such as species composition and biomass has been demonstrated to be affected by ungulates in other studies. Therefore, we propose that ungulate browsing -despite weak effects of browsing exclusion in our study -can affect arthropod predation via changes in the understory, which could potentially affect pest populations. Our study is one of the first attempts to connect effects of mammalian browsing to changes in predation rates on herbivorous insects.(c) 2022 The Authors. Published by Elsevier GmbH on behalf of Gesellschaft fur Okologie. This is an open access article under the CC BY license (


Alces alces; Herbivory; Herbivore damage; Predators; Exclosure experiment; Plasticine larvae

Published in

Basic and Applied Ecology
2023, Volume: 66, pages: 1-10