Weigelt, A; Röttgermann, M; Steinlein, T; Beyschlag, W: Influence of water availability on competitive interactions between plant species on sandy soils, Folia Geobotanica, 35, 169-178 (2000)
Abstract: The gravimetric soil water content of four different successional stages of inland dune vegetation revealed pronounced seasonal changes and particularly a major drought period in late summer. In order to analyze the effect of these seasonal changes on the competitive interactions within these plant communities, the root development of two dominant species (Carex arenaria L. and Deschampsia flexuosa L. (Trin.)) of one of these stages was compared under experimentally manipulated water conditions in a minirhizotron experiment. Under well watered conditions, root growth of C. arenaria was not influenced by competition, but was significantly reduced at low water availability after only 18 days. In both species relative yield (RY) calculated from these data were significantly lower under water shortage than under well watered conditions. These results indicate (1) that soil water status is an important factor for belowground competitive interactions and (2) that seasonal changes in soil water content may have a pronounced effect on the outcome of competition and, in consequence, on the structure of the respective plant communities.

Keywords: soil water content, belowground competition, plant community, relative competition intensity, relative yield, Carex arenaria, Deschampsia flexuosa

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