title: Competition intensity and its importance: results of field experiments with Anthoxanthum odoratum.
abstract: The effect of community productivity on competition was studied in 82 permanent plots using two removal experiments with the rhizomatous perennial grass Anthoxanthum odoratum. The removal of neighbouring plants had a positive effect on the number of shoots and total above-ground biomass of Anthoxanthum but no significant effect on mean shoot biomass. The relative competition intensity coefficient (RCI) calculated from these data showed that competition intensity increased with increasing community productivity. Similarly, the importance of competition and the difference between local maximum and local average population density increased with increasing community productivity. We concluded that for Anthoxanthum the impact of competition is greater in high-productivity areas and that competition reduces population density. No evidence was found supporting the importance of positive interactions between plants in tundra areas.
authors.affiliation: Institute of Zoology and Botany, Estonian Agricultural University, Riia 181, 51014 Tartu, Estonia e-mail: marek@zbi.ee Tel.: +372-7-428619, Fax:+372-7-383013, Estonia.|University of Tartu, Institute of Botany and Ecology, Lai 40, 51005 Tartu, Estonia, Estonia.
authors.forename: M
authors.initials: M
authors.lastname: Sammul
authors.affiliation: Institute of Zoology and Botany, Estonian Agricultural University, Riia 181, 51014 Tartu, Estonia e-mail: marek@zbi.ee Tel.: +372-7-428619, Fax:+372-7-383013, Estonia.|University of Tartu, Institute of Botany and Ecology, Lai 40, 51005 Tartu, Estonia, Estonia.
authors.forename: K
authors.initials: K
authors.lastname: Kull
authors.affiliation: Umeå University, Department of Ecology and Environmental Science, 901 87 Umeå, Sweden, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Oksanen
authors.affiliation: Institute of Zoology and Botany, Estonian Agricultural University, Riia 181, 51014 Tartu, Estonia e-mail: marek@zbi.ee Tel.: +372-7-428619, Fax:+372-7-383013, Estonia.
authors.forename: P
authors.initials: P
authors.lastname: Veromann
keywords: Key words Importance of competition; Productivity; Removal experiments; Tundra; Wooded meadow