Lokální adaptace vzácné byliny Aster amellus ve fragmentované krajině

Raabová, Jana

This thesis aimed to test specific hypothesis conceming habitat differentiation, local adaptationand outbreedingdepressionof the rare herb of dry calcareous grasslands,lsler amellus. Chapter I examined habitat requirementsof diploid and hexaploid A. amellus and their role in segregationof the two cýotypes in the Czech Republic. I chose three diploid and six hexaploid populations belonging to two habitat types (with low and high productivity). To test for differences in fundamental niche between the two cýobpes' I analysedhabitatcharacteristicsof sites occupiedby each cýotype and usedreciprocalhansplantexperiments.Then,I testedtheeffectsofhabitattype,ploidy level andpopulationoforigin on plantperformancein theexperiments. Sites of diploid and hexaploid populationsdiffered significantly in vegetation and soil propertiesbut much overlap existed in habitat characteristicsof the two cytotypes. Diploids had overall higher flowering percentage than hexaploids, suggesting differences between the two cytotypes. However, plants frorn sites with low productivity also flowered more than plants from sites with high productivity. Moreover, the largest differences in survival, leaf length and flowering were found amongplants from different populations.This suggeststhatoverall performanceoťl. amellus differs more...

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