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


Herbivores play a key role in shaping ecosystem structure and functions by influencing plant and microbial community composition and nutrient cycling.
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

Last updated on 2021-20-09 at 16:05