Calamagrostis epigejos (L.) Roth: Bestandesstruktur, Gesamtbiomasse und Biomasseverteilung an unterschiedlichen Standorten

Abstract

Grüttner, A.; Heinze, U.: Calamagrostis epigejos (L.) Roth: Stand structure, total biomass and biomass allocation in different habitats. - Hercynia N.F. 36 (2003): 235–259.Calamagrostis epigejos is very common in Central Europe and occupies an extraordinary wide range of habitats. One reason for its success might be related to the outstanding variability in traits of stand structure. In this case the variability should be in parts habitat specific and not merely depend on stand vigour (allometric effect). We investigated 21 stands, growing in six habitat types. The analysis of habitat parameters and phytocoenoses confirmed differences between the habitat types and also within. Total dry biomass (without roots) differed between 300 and 1500 g/m2 and high variation of structural traits and allocation was found. There were several indications of habitat specific structural peculiarities. A rapidly expanding stand was distinguished by more shoots per tussock, a high share of flowering shoots in relation to total biomass, and longer rhizomes. Taking into account data from literature as well, this seems to be typical for the edges of expanding stands. In search for allometric effects, the relations between traits and total biomass were investigated. Except for forest stands, the length of nonflowering shoots increased with total biomass, but there were indications of a trade off between length and density of nonflowering shoots. C. epigejos stands in pine forests had very long nonflowering shoots in spite of low total biomass, and low biomass per nonflowering shoot. The length was less variable in flowering than in nonflowering shoots – indicating a higher importance of this trait to the species‘ fitness. Where total biomass was low (pine forests, ashes), investment into sexual reproduction was also low, whereas the biomass share of rhizomes was high. With higher total biomass there was no allometric relation in biomass partitioning. Instead a negative relation between the biomass shares of rhizomes (clonal reproduction) and „panicles and culms” (sexual reproduction) was found, whereas no correlation existed between the biomass shares of leaves and of rhizomes. This indicates a genetic trade-off between the biomass shares of rhizomes and „panicles and culms”. Altogether, parts of the variability seem to serve the adjustment to contrasting habitats. Important in this context is the option of a long-lived clonal plant to reduce the investment into sexual reproduction to a very low level.