Demographic structure of clonal, endemic, and endangered rheophyte bromeliad Dyckia ibiramensis: asexual vs sexual reproduction

Abstract

Abstract In southern Brazil some species of Dyckia genus occur as rheophytes. Dyckia ibiramensis is an endemic bromeliad that occurs in discrete patches of the rocky banks along Itajaí do Norte River, Santa Catarina state. Four populations along Itajaí do Norte River were studied. In each population, all rosettes were counted and the diameter of each rosette was measured. The spatial distribution of the rosettes was identified as an isolated rosette or a clump. The clumps were classified according to the number of rosettes. The total number of rosettes per population ranged from 295 to 1,412. Most rosettes occur in clumps (98.1%), and 41% have reproductive rosettes. The number of rosettes per clump ranged from two to 43 rosettes. The percentage of reproductive rosettes per population ranged from 7.8 to 26.7%. The correlation between the number of clumps or between the total number of rosettes and the area of occupation was significant and positive. Few seedlings and isolated rosettes, production of offshoots occurred on both immature, and reproductive rosettes, and clumps with few rosettes can indicate the clonal propagation predominate in D. ibiramensis. Therefore, the maintenance and monitoring of the populations are essential for its long-term in situ conservation.