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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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The role of ultraviolet light in communication of birds
Šulc, Michal ; Sedláček, Ondřej (advisor) ; Albrecht, Tomáš (referee)
Recently, it has been found that the visual system of birds and humans differ remarkably, especially in the ability to perceive ultraviolet radiation. This component of the spectrum significantly affects various types of the birds' behaviour. UV reflection may be an indicator of the qualities of males, i.e. females often prefer individuals with expressive UV ornamentation. Likewise, parents can distribute the delivered food unevenly among their nestlings, depending on the nestlings' reflection of ultraviolet radiation. Recent studies also showed that the hosts of brood parasites may use UV spectrum as a key for recognizing the parasitic eggs from their own. The aim of my bachelor thesis is to review the current knowledge of the influence of UV radiation on sexual selection of birds, the interaction between parents and offspring and interactions between brood parasites and their hosts.
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The effect of climate change and land use change on the long-term population trends of birds in the Czech Republic
Koschová, Michaela ; Reif, Jiří (advisor) ; Voříšek, Petr (referee)
There are number of future projections of species' geographic ranges developed under conditions of ongoing climate change. However, only a few studies have assessed what are the characteristics of species explaining interspecific variability in the projected range shifts. Examination of such relationships is important for development of effective conservation strategies mitigating the effects of climatic changes. For this purpose, I calculated the predicted shifts of European ranges in Czech birds based on maps in A Climatic Atlas of European Breeding Birds and explored relationships between these predicted shifts and several ecological traits. We found significant effects of the type of European distribution and habitat requirements. Concerning the type of European distribution, the largest shift is predicted in the central species and the northern species compared to widespread and southern species. According to the habitat type, the largest shift showed forest birds in contrast to the urban species which will shift slightly. The former pattern is probably attributable to spatial constrains different among these specific groups (central species are less limited compared to widespread species). The latter pattern could be explained by higher sensitivity of forest species to climatic changes...
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Trade-off between egg size and number at the level of bird families
Špaldoňová, Alexandra ; Hořák, David (advisor) ; Reif, Jiří (referee)
Trade-off between offspring size and number belongs to the most discussed concepts in the life history theory. The aim of this study was to elucidate the relationship between egg size, clutch size and female body mass at the family level in bird's and to examine whether there is the relationship between offspring size and number and life history traits specific for particular bird families. From published sources, I collected data about 5.073 species belong in 146 families. Most species of birds lay smaller clutches, on average three eggs. In 112 families from 130 tested eggs size was positively correlated with female body mass. There is evidence that egg size and clutch size are inversely related in 83 families from 130 tested but only for 34 families was significant. The relationship exists independently of female body mass across bird families and this suggests a trade-off between these traits. The relationship between the strength and shape of egg size-number correlations and life history characteristics of bird families was not frequent. According to results, the strength of correlation seems to be related to development mode and diet type. The negative egg size-number correlation is stronger when incubation period and fledging time is longer and in birds with longer lifespan. The...
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The long-term trends in numbers and distribution of birds in the Czech Republic
Gebauer Fialová, Adéla ; Musil, Petr (advisor) ; Fuchs, Roman (referee)
The long-term changes in distribution and numbers of bird species in the Czech Republic were analysed using published data from Breeding Birds Atlases in the Czech Republic (1973-77, 1985-89 and 2001-03). Each species were categorized by taxonomical group, migratory strategies, biogeography type, breeding habitat, breeding population size in Europe and in the Czech Republic a body size. The changes in numbers and changes in distribution were inter-correlated Increase in distribution as well as in numbers were recorded in rare and large species, in species increasing in whole Europe and in bird species protected under Czech legislation. Interesting pattern in population was found in waterbirds, where piscivorous species are increasing, whereas other (mostly grebes, ducks etc.) species are decreasing.
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Factors influencing the ecological stability of the Novozamecky rybnik Reserve
Hanzelka, Jan ; Reif, Jiří (referee) ; Čihař, Martin (advisor)
Fishponds and their surroundings are affected by many factors disrupting their ecological stability. In this thesis, influences of selected factors are evaluated. Particularly it is discussed excessive overgrowing of shoreline by plants, pond siltation by allochthonous material from catchment area, eutrophication process and intensive fish farming. It is presented the impact of these factors on local avifauna in Novozámecký fishpond National Nature Reserve and Special Protection Area and compared with Třeboňsko Special Protection Area. Birds use the ponds especially as nesting habitat and food source. Therefore, it is necessary to describe the influences disrupting this habitat. The frugal interference with mentioned processes is needed in terms of dynamics of the ecological stability. Thereby the requested fishpond parameters and ecological and economic values will be maintained. Fisheries management and lack of historical management in the form of reasonably performing mowing and grazing in the vicinity of the ponds has the greatest impact on the habitat of birds upon Třeboň fishponds. Novozámecký pond also suffers from the lack of historical management, but the unsatisfactory state of the pond is rather due to the overall eutrophication of the environment.
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Ohrožení ptáci zemědělské krajiny- přednáška a pracovní list
BUCHALOVÁ, Martina
The birds of agricultural landspace are currently the most disappearing kind of birds. Their decline is connected with the rate and the way of farming in this landscape. Thus it is extremely important to inform the general public about this issue. The diplom thesis contains a lecture and a worksheet dealing with this issue and they are aimed at high school students.
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Diet structure of Tengmalm’s owl (Aegolius funereus) in the Ore Moutains in 2014-2015: the effect of laying date on the presence of Microtus voles and birds (Aves)
Šimková, Kristýna ; Šťastný, Karel (advisor) ; Kouba, Marek (referee)
Diet structure of Tengmalm s Owl was studied during 2014-2015 in the Loučeň area of the Ore Mountains specifically around the Flájská dam area of 70 km2. This area is strongly affected by emissions. Diet research was conducted with method of pellets analysis which were taken from nest boxes during nesting period. 32 samples were collected during this two years study. Each sample represents content of diet from one nest box during one
nesting period. 6 samples with 259 individuals were from 2014 while 26 samples with 1349 individuals were collected in 2015. In total 1608 individuals were found during 2014-2015, out of them 33 birds (Aves) and 1575 mammals (Mammalia). Diet content was changing during study years, depending on availability of prey. Main part of diet represented mammals (97,9 %), rest of diet was built by birds (2,1 %). Between 2014-2015 mammals were found in following proportion: Apodemus sp. - 52,8 %, Microtus agrestis - 25,1 %, Microtus sp. - 8,0 %, Sorex araneus - 3,0 %, Clethrionomys glareolus - 2,7 %, Microtus arvalis - 2,0 %, Muscardinus avellanarius - 0,6 %, Sorex minutus - 0,5 %, Micromys minutus - 0,1 % and birds in proportion: Turdus philomelos - 0,4 %, Phylloscopus sp. - 0,4 %, Aegolius funereus - 0,2 %, Erithacus rubecula - 0,2 %, Pyrrhula pyrrhula - 0,2 %, Fringilla coelebs - 0,1
%, Parus major - 0,1 %, Anthus trivialis - 0,1 %, Carduelis cannabina - 0,1 %, Ficedula sp. - 0,1 %, Garrulus landarius - 0,1 %, Regulus regulus - 0,1 %, Sylvia atricapilla - 0,1 %, Turdus merula - 0,1 %. Main objective of this study was to evaluate proportion of voles and birds in diet during study reflecting timing of Tengmalm s Owl s nesting. During two years evaluation was proved difference in proportion of birds in diet of Tengmalm s Owl. In 2014 birds represented 15,3% of diet while in 2015 birds were not represented at all. Proportion of voles (Microtus agrestis, Microtus arvalis and Microtus sp.) in Tengmalm s Owl s diet didn t differ significantly during study period.
It was found that in 2014 neither proportion of voles nor birds in Tengmalm s Owl s diet didn t change significantly during nesting period thus the effect of nesting timing on diet content wasn t proved. During 2015 nesting period the proportions of voles in Tengmalm s Owl s diet significantly grew and impact of nesting timing was proved. Birds were not represented in owl s diet at all in this year.
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