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Population trends, threats and conservation of island endemic birds
Rohová, Kateřina ; Reif, Jiří (advisor) ; Sam, Kateřina (referee)
As endemics are considered plant and animal species including birds, which are in the focus of this thesis, that are found in a restricted geographic region and nowhere else in the world. Such endemics typically occur on the islands that are often recognized as important global biodiversity hotspots. However, many endemic species are very vulnerable due to numerous factors (mainly genetic and demographic) closely linked to the way of life on the islands. Huge effort is dedicated to their conservation, and it thus reasonable to ask whether such an effort made a significant contribution to prevent their loss. Here, I evaluate the overall success of island bird endemics conservation compared to continental conditions because such a global analysis has been lacking up to now. In addition, this thesis examines how three major threatening factors (namely habitat destruction, invasive species, and overexploitation) driven by anthropogenic activities affect population trends of continental and island bird species. Finally, I mapped and explained, using examples, which conservation tools are effective for supporting the populations of island endemic species. The results of statistical analyses, based on a global dataset containing almost 8000 avian species, showed that island endemic species are more...
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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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