engleski

POPULATION SIZE, CONSERVATION STATUS AND MORPHOLOGICAL CHARACTERIZATION OF CRITICALLY ENDANGERED DOWNY BIRCH (BETULA PUBESCENS EHRH.) AND HYBRID BIRCH (B. x BLATUSAE PEVALEK) IN CROATIA

Downy birch (Betula pubescens Ehrh.) in Croatia is on the southern edge of its area of distribution and is member of bog vegetation. Due to disappearing of its natural habitats it is considered a critically endangered species of Croatian flora. The aim of this research was to determine the recent distribution and population size of downy birch and hibridogenous taxon B. x blatusae Pevalek, a hybrid between downy and silver birch (B. pendula Roth) in Croatia. The research was performed on the only two known locations of downy birch in Croatia: in Botanical reserve „Đon Močvar“ near the village of Blatuša (Banovina Region) and above the stream Ludvić potok, below the village of Gradišće (surroundings of town of Samobor). The counting of the individuals revealed that populations of downy birch are extremely small and endangered ; the population near Ludvić potok consists of only three, while population at Đon Močvar of 63 individuals, of which just a small number fructificate. Hybridogenous birch has been recorded only at Đon Močvar with total of 56 individuals. Based on this results, a risk status according to IUCN categorization for the populations of downy and hybridogenous birch in Croatia has been estimated. In addition, based on measured 10 morphological leaf characters of silver, downy and hybrid birch, morphological differences have been identified and the determination key has been proposed.

Betula pubescens; hybridisation; population size; morphometrics; conservation

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