Herbivore effects on ecosystem process rates in a low-productive system
|Author:||Tuomi, Maria1; Stark, Sari2; Hoset, Katrine S.1;|
1Section of Ecology, Department of Biology, University of Turku, 20014 Turku, Finland
2Arctic Centre, University of Lapland, 96301 Rovaniemi, Finland
3Ecology and Genetics Research Unit, University of Oulu, P. O. Box 8000, 90014 Oulu, Finland
4Department of Arctic and Marine Biology, UiT - Arctic University of Norway, 9037 Tromsø, Norway
5Department of Forest Resource Management, Swedish University of Agricultural Sciences, 90183 Umeå, Sweden
|Online Access:||PDF Full Text (PDF, 1.5 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe2019060318165
|Publish Date:|| 2019-06-03
Mammalian herbivores shape the structure and function of many nutrient-limited or low-productive terrestrial ecosystems through modification of plant communities and plant–soil feedbacks. In the tundra biome, mammalian herbivores may both accelerate and decelerate plant biomass growth, microbial activity and nutrient cycling, that is, ecosystem process rates. Selective foraging and associated declines of palatable species are known to be major drivers of plant–soil feedbacks. However, declines in dominant plants of low palatability often linked with high herbivore densities may also modify ecosystem process rates, yet have received little attention. We present data from an island experiment with a 10-year vole density manipulation, to test the hypothesis that herbivores accelerate process rates by decreasing the relative abundance of poorly palatable plants to palatable ones. We measured plant species abundances and community composition, nitrogen contents of green plant tissues and multiple soil and litter variables under high and low vole density. Corroborating our hypothesis, periodic high vole density increased ecosystem process rates in low-productive tundra. High vole density was associated with both increasing relative abundance of palatable forbs over unpalatable evergreen dwarf shrubs and higher plant N content both at species and at community level. Changes in plant community composition, in turn, explained variation in microbial activity in litter and soil inorganic nutrient availability. We propose a new conceptual model with two distinct vole–plant–soil feedback pathways. Voles may drive local plant–soil feedbacks that either increase or decrease ecosystem process rates, in turn promoting heterogeneity in vegetation and soils across tundra landscapes.
|Pages:||827 - 843|
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
1172 Environmental sciences
1181 Ecology, evolutionary biology
Study was supported by Turun yliopistosäätiö (MT) and the Academy of Finland (LO, SS). LO, KSH and MT of the research team were part of NCoE Tundra, funded by the Norden Top-Level Research Initiative “Effect studies and adaptation to climate change” from 2011 to 2015.
© The Author(s) 2018. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.