A1 Journal article (refereed)
Grazing decreases N partitioning among coexisting plant species (2017)
Barthelemy, H., Stark, S., Kytöviita, M.-M., & Olofsson, J. (2017). Grazing decreases N partitioning among coexisting plant species. Functional Ecology, 31(11), 2051-2060. https://doi.org/10.1111/1365-2435.12917
JYU authors or editors
Publication details
All authors or editors: Barthelemy, Hélène; Stark, Sari; Kytöviita, Minna-Maarit; Olofsson, Johan
Journal or series: Functional Ecology
ISSN: 0269-8463
eISSN: 1365-2435
Publication year: 2017
Volume: 31
Issue number: 11
Pages range: 2051-2060
Publisher: Wiley-Blackwell Publishing Ltd.
Place of Publication: Chichester
Publication country: United Kingdom
Publication language: English
DOI: https://doi.org/10.1111/1365-2435.12917
Research data link: https://doi.org/10.5061/dryad.78084
Publication open access: Not open
Publication channel open access:
Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/55877
Abstract
This study investigated the long‐term effects of herbivores on plant resource acquisition. We explored differences in the natural δ15N signatures in plant, microbial and soil N pools, and examined mycorrhizal colonization in two tundra sites that have been either lightly or heavily grazed by reindeer for more than 50 years. The study examined changes in nutrient acquisition in five common tundra plants with contrasting traits and mycorrhiza status; the mycorrhizal dwarf shrubs, Betula nana, Vaccinium myrtillus and Empetrum hermaphroditum; a mycorrhizal grass, Deschampsia flexuosa, and a non‐mycorrhizal sedge, Carex bigelowii.
There were large variations in δ15N among coexisting plant species in the lightly grazed sites. This variation was dramatically reduced in the heavily grazed sites. At an individual species level, δ15N was higher in E. hermaphroditum and lower in C. bigelowii in the heavily grazed sites. Mycorrhizal colonization in B. nana and E. hermaphroditum roots were also lower in the heavily grazed sites. The δ15N signatures of the total soil N pool and of the microbial N pools were higher in the heavily grazed sites.
Since the strong δ15N differentiation among plant species has been interpreted as a result of plants with different mycorrhizal types using different sources of soil nitrogen, we suggest that the lower variation in δ15N in heavily grazed sites indicates a lower niche differentiation in nitrogen uptake among plants. Reduced mycorrhiza‐mediated nitrogen uptake by some of the species, a shift towards a more mineral nutrition due to higher nutrient turnover, and uptake of labile nitrogen from dung and urine in the heavily grazed sites could all contribute to the changes in plant δ15N.
We conclude that herbivores have the potential to influence plant nutrient uptake and provide the first data suggesting that herbivores decrease nutrient partitioning on the basis of chemical N forms among plant species. Reduced niche complementarity among species is potentially important for estimates of the effects of herbivory on plant nutrient availability and species coexistence.
Keywords: tundra; biomass (industry); nutrients (animals and humans); plants; nutrient cycle; nutrients (plants)
Free keywords: above-belowground linkages; arctic tundra; microbial N biomass; mycorrhizal colonization; nutrient cycling; plant-herbivore interactions; plant nutrient uptake; ungulate grazing
Contributing organizations
Ministry reporting: Yes
Reporting Year: 2017
JUFO rating: 2
