Research article - Peer-reviewed, 2008
Impact of simulated moose densities on abundance and richness of vegetation, herbivorous and predatory arthropods along a productivity gradient
Suominen, Otso; Persson, Inga-Lill; Danell, Kjell; Bergstrom, Roger; Pastor, JohnAbstract
Large herbivores can affect vegetation structure and species composition as well as material and energy flows in the ecosystem through their selective feeding, defecation, urination and trampling. These changes have a large potential to indirectly affect other trophic levels, but the mechanisms are poorly known. We studied the impacts of moose Alces alces browsing along a gradient of site productivity by experimentally simulating four different moose densities. Here we show that moose can affect the richness and abundance of three trophic levels in Swedish boreal forests through complex direct and indirect impacts, but in qualitatively different ways depending on how the physical habitat or food resources of a trophic level are affected. Vegetation richness had a hump-shaped (unimodal) response to increased moose density. Leaf litter production decreased when browsing increased, which in turn depressed the abundance of flying prey for spiders. Consequently, spider abundance and richness declined monotonically. The responses of spider richness to moose density were further conditioned by site productivity: the response was positive at productive and negative at unproductive sites. In contrast, herbivorous Hemiptera were not affected by moose, most likely because the abundance of their food plants was not affected. The highest simulated moose density had an impact on all variables responding to moose even after a few years of treatment and can be considered as overabundance. We also show that the impacts of low or moderate moose density can be positive to some of the organisms negatively affected by high density. The level of herbivore population density that leads to substantial community impacts also depends on site factors, such as productivity.Published in
Ecography2008, volume: 31, number: 5, pages: 636-645
Publisher: BLACKWELL PUBLISHING
Authors' information
Suominen, Otso
University of Turku
Persson, Inga-Lill
Swedish University of Agricultural Sciences, Department of Wildlife, Fish and Environmental Studies
Swedish University of Agricultural Sciences, Department of Wildlife, Fish and Environmental Studies
Swedish University of Agricultural Sciences, Department of Wildlife, Fish and Environmental Studies
Forestry Research Institute of Sweden, Skogforsk
Pastor, John
University of Minnesota
UKÄ Subject classification
Environmental Sciences related to Agriculture and Land-use
Publication Identifiers
DOI: https://doi.org/10.1111/j.0906-7590.2008.05480.x
URI (permanent link to this page)
https://res.slu.se/id/publ/19335