Ramet demography in a ring-forming clonal sedge
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1 In a calcareous dry grassland community in central Europe genets of the clonal sedge Carex humilis form very distinct rings of densely aggregated ramets. As genet growth form is generated by ramet population dynamics, ramet demography must be studied in order to understand how rings develop. We analysed how ramet demography in C. humilis depends on ramet position within the ring and how this is linked to ramet size. 2 The per ramet population growth rate was > 1 at the periphery of rings but < 1 in the interior, meaning that the population increases at the periphery but decreases in the interior. The population growth rate differed mainly because ramets were smaller in the interior and because smaller ramets produced fewer vegetative ramets. It is unlikely that the smaller ramet size is caused by negative density dependence, interspecific competition, internal control or resource depletion. 3 The study covered four growing seasons and we found considerable variation in ramet demography between years. The net result for the 4 years was that the total number of C. humilis ramets in the population increased. However, both production of vegetative ramets and ramet size decreased during the study period and if this trend continues population size will instead decrease.