Quantitative Ecological Studies from Landmannahellir, Iceland III. Variation of Performance in Carex Bigelowii

Abstract

The variation of performance of Carex bigelowii can be related to 2 factors, an intrinsic relationship between the age of an individual rhizome and its performance and also the effect of micro-environment on the individual. The performance age-relationship is expressed as a curve of the form ax2 +bx+c. An investigation of the pattern and inter-relations between Carex, Festuca rubra, and micro-topography shows conclusively the more extreme effect of microtopogra-phy on the performance of Carex relative to the effect on the density of Carex. A similar relationship between Festuca and Carex performance is related to competition between the species, and the results are discussed in relation to general considerations of community dynamics and non-randomness in vegetation.