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The population biology of a narrow endemic, centuarea tchihatcheffii fisch and mey.(compositate), in Ankara Turkey

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2005
Çakaroğulları, Didem
Centaurea tchihatcheffii Fisch. & Mey. is a critically endangered annual plant species with a narrow distribution in Gölbaşı, Ankara. The aim of this study is to understand the population dynamics of the species to help find the best way to conserve species for long term viability. The two healthiest subpopulations containing more than 1.5 million individuals were studied to estimate demographic parameters i.e. survival and reproduction rates by monitoring marked individuals, to identify pollinators, dispersers and pollen & seed predators and to investigate population status, natural threats and their effects. The species is considered a weed in cereal plantations, showing adaptations of ruderal habit: High population densities (~18.5-63.2 individuals/0.5 m2), persistent seed bank with many viable seeds (~20,000/m2), rapid growth matching favorable weather conditions (almost 15 weeks from rosette to flowering), high survival with premature deaths making up only 2-20% of natural deaths mostly at rosette stage, no density dependent mortality, seed production by selfing and crossing via generalist pollinators, high reproduction rates (1200-7000 seeds/m2) and promotion of growth on aerated soil whereas inhibition with herbicides. Insect and avian predators do not cause an important damage to population. Absence of mutualists aiding in pollination (honeybee) and dispersal (ants) is out of question. There is no natural limitation on population persistence. The major threats are anthropogenic, i.e. cereal cultivation, construction and collection of individuals from natural populations. Conservation of remaining subpopulations as a reserve and alternative methods in cereal cultivation like reduced or no herbicide application should be considered as high priority conservation strategies.