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Interspecific hybridization in birds: lessons for conservation
Štěpánková, Klára ; Reif, Jiří (advisor) ; Vokurková, Jana (referee)
Interspecific hybridization is quite common in recent years. Favorable factors are rarity of a species, limited time for partner selection, misdirected preference in mating partner selection of females, preference for males with more pronounced sexually selected traits, greater body size and habitat destruction. Factors which lead to the artificially interspecific hybridization due to habitat destruction include deforestation, fragmentation of the territory, urbanization, abandoning agricultural areas, as well as translocation of species into the regions where they did not originally occur. These species can later interbreed with the native species and if the latter are rare and the former aggressive, it can result in increased threat potentially leading to extinction of indigenous populations. Exceptionally, interbreeding can lead to the emergence of a new species; however, this type of origination of a new species is not common in animals. Hybridization is a natural phenomenon important for the evolution. Nevertheless, anthropogenically induced or assisted hybridization represents a serious problem for the species conservation. Finding a solution to overcome the negative impacts of such interspecific hybridization is difficult and there is no exact and universally applied methodology to date. Key...
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Interspecific hybridization in birds: lessons for conservation
Štěpánková, Klára ; Reif, Jiří (advisor) ; Vokurková, Jana (referee)
Interspecific hybridization is quite common in recent years. Favorable factors are rarity of a species, limited time for partner selection, misdirected preference in mating partner selection of females, preference for males with more pronounced sexually selected traits, greater body size and habitat destruction. Factors which lead to the artificially interspecific hybridization due to habitat destruction include deforestation, fragmentation of the territory, urbanization, abandoning agricultural areas, as well as translocation of species into the regions where they did not originally occur. These species can later interbreed with the native species and if the latter are rare and the former aggressive, it can result in increased threat potentially leading to extinction of indigenous populations. Exceptionally, interbreeding can lead to the emergence of a new species; however, this type of origination of a new species is not common in animals. Hybridization is a natural phenomenon important for the evolution. Nevertheless, anthropogenically induced or assisted hybridization represents a serious problem for the species conservation. Finding a solution to overcome the negative impacts of such interspecific hybridization is difficult and there is no exact and universally applied methodology to date. Key...
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Risk of hybridization of threatened P. fruticosa with cultivated Prunus species
Musilová, Lenka ; Vít, Petr (advisor) ; Zahradníček, Jaroslav (referee)
Many agriculturally important fruit trees occur in the genus Prunus, among other also Sour cherry (Prunus cerasus) and Sweet cherry (Prunus avium). P. cerasus is considered to be an allopolyploid hybrid originated by hybridization of Prunus fruticosa (2n = 4x = 32) and P. avium (2n = 2x = 16). The world production of sour cherry fruit (P. cerasus) in 2008 is estimated to be more than 1, 15 million tones. Prunus fruticosa is a steppe (forest steppe) relict species, severely endangered in the Czech Republic (C2). The main threat of P. fruticosa are both the direct and indirect human activities, causing, above all the loss of natural biotopes and hybridization with cultivated species that ran wild to the nature. P. fruticosa hybridizes all over its occurrence area with wild P. cerasus (Sour cherry; which is not primary species of the Czech Republic) and originates fertile hybrid Prunus × eminens. The results of existing studies indicate that the hybrids are more common in the central Europe and that the frequency of hybridization rises towards the west. Such phenomenon is related to human activities (cherries cultivation and landscape changes). Many authors consider hybridization to be the main cause of endangerment of this species and noticed that in many habitats the hybrids could totally replace...
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