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Linkages of nitrogen and phosphorus availability to ecosystem processes and succession in forests of northern Sweden and New Zealand

Lagerström, Anna (2009). Linkages of nitrogen and phosphorus availability to ecosystem processes and succession in forests of northern Sweden and New Zealand. Diss. (sammanfattning/summary) Umeå : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2009:95
ISBN 978-91-576-7442-5
[Doctoral thesis]

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Initially after catastrophic disturbance ecosystems undergo a build-up phase but in the long term absence of catastrophic disturbance ecosystems can enter a phase of decline called ecosystem retrogression. It is characterised by reduced productivity, decomposition rates and rates of nutrient cycling as a consequence of nutrient limitation. Over the course of long-term soil development, phosphorus (P) availability decreases due to leaching and chemical immobilisation, leading to increased soil N: P ratios during retrogression. In contrast, nitrogen (N) is continuously supplied to natural ecosystems through biological N2 fixation, though late successional plant species can have a negative effect on N availability during retrogression, reinforcing N limitation. I studied variation in supply and availability of N and P throughout a 5000 year retrogressive chronosequence in which the soil N: P ratio increases, and investigated how it affected the nutrient status of soil microbes and plants. I found that total N increases considerably during retrogression as a consequence of increased N2 fixation. Total P did not change across the chronosequence but labile mineral P declined in the retrogressive stage and this was connected to decreased soil microbial activity. Plant nutrient status showed diverging trends between trees and dwarf shrubs across the chronosequence, indicating increasing resource partitioning as retrogression proceeds. Variation in leaf traits was due to shifting species composition rather than within species changes. I also studied factors influencing the availability of N and P during the build-up phase of succession as affected by an important extrinsic driver, i.e., herbivory. Herbivory of a N2 fixing shrub had considerable negative effects on the nutrient status of not only its own growth and nutrient status, but also that of neighbouring non-fixing plants and soil processes. These studies in combination have demonstrated how changing availability of nutrients during succession, both in the build-up phase and the retrogressive phase, can be driven by biological processes such as N2 fixation and species effects on carbon (C) quality and, how this in turn leads to differences in the relative success of coexisting plant species in the community. As such, these results demonstrate the dynamic and variable nature of nutrient limitation and the processes leading to it.

Authors/Creators:Lagerström, Anna
Title:Linkages of nitrogen and phosphorus availability to ecosystem processes and succession in forests of northern Sweden and New Zealand
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2009
Number of Pages:51
ALLPaper I Lagerström A, Nilsson M-C, Zackrisson O, Wardle DA (2007). Ecosystem input of nitrogen through biological fixation in feather mosses during ecosystem retrogression. Functional Ecology 21, 1027-1033. Paper II Lagerström A, Esberg C, Giesler R, Wardle DA (2009). Soil phosphorus and microbial response to a long-term wildfire chronosequence in northern Sweden. Biogeochemistry 95, 199-213. Paper III Lagerström A, Nilsson M-C, Wardle DA. Response of leaf and litter nutrients, and nutrient resorption, to ecosystem retrogression on boreal forested islands in northern Sweden (manuscript). Paper IV Lagerström A, Bellingham PJ, Bonner KI, Wardle DA. The effect of simulated herbivory on growth and nutrient status of focal and neighbouring plants (manuscript).
Place of Publication:Umeå
ISBN for printed version:978-91-576-7442-5
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:nitrogen, phosphorus, ecosystems, ecological succession, nitrogen fixation, wildfires, boreal forests, sweden, new zealand
Keywords:Nitrogen, phosphorus, succession, wildfire, retrogression, boreal forest, N2 fixation, N: P ratio, herbivory
Permanent URL:
ID Code:2164
Department:(S) > Dept. of Forest Ecology and Management
Deposited By: Anna Lagerström
Deposited On:17 Nov 2009 00:00
Metadata Last Modified:02 Dec 2014 10:16

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