Biomass production, N:P ratio and nutrient limitation in a Caucasian alpine tundra plant community

Authors

  • N.A. Soudzilovskaia,

    Corresponding author
    1. Department of Geobotany, Biological Faculty, Moscow State University, Moscow, 119992, Russia
    2. Institute of Ecological Science, Department of Systems Ecology, Vrije Universiteit, De Boelelaan 1085, NL-1081 HV Amsterdam, The Netherlands
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  • V.G. Onipchenko,

    1. Department of Geobotany, Biological Faculty, Moscow State University, Moscow, 119992, Russia
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  • J.H.C. Cornelissen,

    1. Institute of Ecological Science, Department of Systems Ecology, Vrije Universiteit, De Boelelaan 1085, NL-1081 HV Amsterdam, The Netherlands
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  • R. Aerts

    1. Institute of Ecological Science, Department of Systems Ecology, Vrije Universiteit, De Boelelaan 1085, NL-1081 HV Amsterdam, The Netherlands
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Corresponding author at the Amsterdam address; E-mail n.soudzilovskaia@zonnet.nl

Abstract

Abstract

Questions:

1. To what extent is biomass production of a Caucasian alpine tundra plant community limited by soil nitrogen and/ or phosphorus? 2. Can the foliar N:P ratio predict the nutrient limitation pattern of alpine vascular plant communities?

Location:

Lichen-rich tundra on Mt. Malaya Khatipara in the NW Caucasus, Russia (43°27’N, 41°42’E; alt. 2800 m a.s.l.).

Methods:

We conducted a 4–year fertilization experiment (N, P, N+P, lime additions and irrigation) on the alpine tundra in the northwestern Caucasus, Russia. We determined responses of biomass, tissue nutrient concentrations and nutrient pools of the above-ground component of the plant community.

Results:

Total plant community biomass did not respond to fertilization. However, lichen biomass strongly decreased in response to the N- and N+P treatments, whereas vascular plant biomass increased in response to the N- and even more to the N+P treatment, but not to P or lime addition or irrigation. P-concentrations in vascular plant species were very low, but their biomass production was not principally P-limited, suggesting adaptation to low soil P-availability. The N-limitation of vascular plant biomass production in the community, which in lowlands usually occurs at N:P ratios below 16, could not be predicted from the mean foliar N:P mass ratio in the control (N:P = 29).

Conclusions:

This Caucasian alpine plant community is an example of N- and P-co-limitation of vascular plant biomass production, with N being the principal and P the secondary limiting nutrient. Critical N:P ratios as determined for lowland communities are not applicable here.

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