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Habitat selection by dragonflies - effect of littoral and riparian vegetation
Bonková, Anita ; Černý, Martin (advisor) ; Waldhauser, Martin (referee)
Dragonflies form one of the important pillars of most aquatic ecosystems and play an important role in maintaining their balance. The main goal of this bachelor's thesis is to summarize current knowledge about the habitat preferences of members of the order Odonata, with a focus on the effect of littoral and riparian vegetation, which are critical components of aquatic biotopes and significantly influence the distribution, abundance and reproductive success of dragonflies. In my work, I focus on all developmental stages, from larvae to adults. These findings are important for the maintenance and revitalization of freshwater ecosystems, in which it is necessary to pay attention to the composition of littoral and riparian vegetation to support the diverse needs of this unique insect order. Key words: habitat preference, dragonflies, Odonata, riparian vegetation, littoral vegetation
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Year-round specialists? Habitat niches of migratory birds on breeding and non-breeding grounds
Zálišová, Jaromíra ; Procházka, Petr (advisor) ; Reif, Jiří (referee)
Migratory birds undertake challenging journeys over vast distances each year to cope with seasonality in their environment and to exploit peaks in seasonal resources. The environments in which they are found in these geographically distinct regions over the course of the annual cycle vary considerably, forcing them to cope with a wide range of conditions. By examining whether migratory birds are year-round specialists that follow their niche or generalists that inhabit a broader range of habitats, we can better understand their ecology and the conservation implications associated with global change. However, our knowledge of habitat selection across seasons is still limited. This thesis aimed to explore and evaluate, through a literature review, existing knowledge on habitat selection by migratory bird species on breeding and wintering grounds. Emphasis was placed on the mechanisms influencing habitat selection, including geographical and anthropogenic influences, as well as to clarify the ecological requirements and potential specialization of migratory birds during their annual cycle. The current literature shows that migratory birds are most likely less opportunistic than previously thought, but a comprehensive analysis of data on habitat use by individual species is still missing and I would...
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Habitat selection in post-breeding temperate forest birds
THRIKKADEERI, Karthik
Habitat selection of forest birds in Branišovský les, České Budějovice, Czech Republic was studied by observing habitat preferences in the non-breeding season and exploring possible shifts in preferences due to the changing seasons. Patterns of habitat selection were analysed at multiple levels: considering all bird species as well as comparing between two feeding guilds. Preferences were also studied by specifically monitoring predation rates by birds on artificial caterpillars and exploring changes with habitat and season.
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The importance of various habitats for fish in reservoirs
Šmejkal, Marek ; Prchalová, Marie (advisor) ; Vašek, Mojmír (referee)
Fish distribution in reservoirs is not homogeneous. Fish usually occur in upper parts of reservoirs on the longitudinal axis, where is also the greatest concentration of nutrients. Fish abundance and biomass as well as the trophy are declining towards the dam part. On the vertical axis, most fish occur above the thermocline, where temperature and concentration of dissolved oxygen reach the highest values. Fish community is changing also in time. Shortly after impoundment, the riverine species are dominating the community and later, generalist species prevail. Generally, we can distinguish pelagic and bentic habitats within the reservoir. There are species in reservoirs that occur almost strictly in pelagic habitat like asp and bleak and benthic species like ruffe and perch. Most species occur in both types of habitats (bream, roach, pikeperch, European catfish, white bream). Migrations between habitats occur on daily and on seasonal basis. On daily basis, we distinguish diel horizontal migration, in which fish shift between pelagic and benthic habitats. Diel vertical migration, when fish change depths, is not so significant in Czech reservoirs. Motivations for these diel migrations are food aviability, predation pressure and water temperature. Seasonal migrations comprise spawning migrations and winter...
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Settlement of the landscape with European beaver (Castor fiber) in relation to anthropogenic influences
Mikulka, O. ; Patočka, Z. ; Drimaj, J. ; Kamler, J. ; Plhal, R. ; Homolka, Miloslav
The European beaver (Castor fiber) is a protected species in the Czech Republic that has spread to the whole of Moravia. Now, it is a common species whose competitor is only human. The aim of this study was to evaluate the impact of human activity, especially tourism or transport, on the settlement of the landscape by the European Beaver. The area of the protected landscape area Litovelske Pomoravi was chosen to evaluate the settlement of the landscape by the beaver, where the beaver forms a stable population for a long time and the frequented cycling routes, hiking trails and the area are frequently visited by natural floodplain forests. The beaver settlement data were collected by means of the winter monitoring of residential stamps using the GPS system in 2017. Data on the location of cycle routes, hiking trails, human settlements and infrastructure were obtained from available GIS layers. Settlement of European beaver was evaluated in relation to the distance and intensity of interference by tourist activities, traffic or buildings. There were 200 km of watercourses in the monitored area. The inhabited beaver was 39% of the length. The beaver avoided human settlements, preferring the natural environment. The influence of tourism on the beaver settlement has not been proven.
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Niche Partitioning in Tropical Birds
Petruf, Miroslav ; Sedláček, Ondřej (advisor) ; Exnerová, Alice (referee)
in English Niche partitioning is a process that allows species to coexist by minimizing competition. Niches get narrow with growing habitat heterogeneity, which is evident in tightly packed tropical communities. Closely related species exhibit a high niche overlap, which intensifies competition for resources in their sympatry. Such birds avoid competitive exclusion by foraging using different methods or in different strata. Character displacement makes sympatric species diverge in foraging niches as well as in morphology, allowing specialized species to access private resources. Tropical birds in seasonal environments tend to occupy different niches in the wet and in the dry season, based on the availability of resources in their preferred habitats. Resource subdivision in sympatric members of an ecological guild usually depends on body-size- determined dominance. Territoriality may depend on the costs and benefits of defending resources, which may change seasonally. Dominance statuses vary within populations of the same species, too, promoting intra-specific niche partitioning. Within-species differences in foraging can also be the result of sexual dimorphism or differences in reproductive roles. Moreover, intra-specific differences in foraging may also explain the partial migration of some...
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The importance of various habitats for fish in reservoirs
Šmejkal, Marek ; Vašek, Mojmír (referee) ; Prchalová, Marie (advisor)
Fish distribution in reservoirs is not homogeneous. Fish usually occur in upper parts of reservoirs on the longitudinal axis, where is also the greatest concentration of nutrients. Fish abundance and biomass as well as the trophy are declining towards the dam part. On the vertical axis, most fish occur above the thermocline, where temperature and concentration of dissolved oxygen reach the highest values. Fish community is changing also in time. Shortly after impoundment, the riverine species are dominating the community and later, generalist species prevail. Generally, we can distinguish pelagic and bentic habitats within the reservoir. There are species in reservoirs that occur almost strictly in pelagic habitat like asp and bleak and benthic species like ruffe and perch. Most species occur in both types of habitats (bream, roach, pikeperch, European catfish, white bream). Migrations between habitats occur on daily and on seasonal basis. On daily basis, we distinguish diel horizontal migration, in which fish shift between pelagic and benthic habitats. Diel vertical migration, when fish change depths, is not so significant in Czech reservoirs. Motivations for these diel migrations are food aviability, predation pressure and water temperature. Seasonal migrations comprise spawning migrations and winter...
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