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Changes in dry grassland and thermophilous forest vegetation and the species traits explaining these changes
Míšek, Vojtěch ; Münzbergová, Zuzana (advisor) ; Větvičková, Anna (referee)
Calcareous dry grasslands and adjacent thermophilous deciduous forests are important biotopes in terms of biodiversity. They have been shaped by human activity for a long time. Grasslands were grazed or mown, forests were coppiced and the litter was raked. The abandonment of these traditional practices is the main cause why both biotopes are threatened nowadays. A return to these forms of management is essential for the restoration and protection of these communities. In my bachelor's thesis, in addition to the characteristics of dry grasslands and deciduous forests and the factors that influence the vegetation of these biotopes, I deal with species traits that can help explain and predict these changes. Key words: xerothermic grassland, thermophilous forest, vegetation change, species traits.
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Species-specific and individual predictors of birds' collisions with glass obstacles in the Czech Republic
Semeráková, Anna ; Sedláček, Ondřej (advisor) ; Viktora, Lukáš (referee)
Recent landscape transformation is associated with the emergence of various artificial obstacles that change the natural form of habitats and biocorridors of free-ranging animals. Glass obstacles represent a particular problem due to their transparency and reflectivity. Collisions with glass represent one of the most significant causes of bird mortality worldwide, accounting for over hundreds of millions bird deaths annually. Many authors consider this source of mortality to be completely non-selective. In that case, total collisions mortality would represent a function of population size. However, here I assume that the relationship between collision mortality and population size is more complex and that certain avian ecological groups may be differently susceptible to glass collisions based on their specific ecological characteristics. Long-term records of bird-glass collisions in the Czech Republic were provided by the Czech faunistic databases. These records were compared with the population size of analysed species and with selected ecological and morphological species characteristics. Consistently with the premise, I found out that the greatest amount of collision mortality is explained by the species' population size. However, other species characteristics, such as higher body weight,...
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Relationships between functional traits, home range sizes, and dispersal abilities in birds
Holubová, Kateřina ; Storch, David (advisor) ; Sedláček, Ondřej (referee)
Avian movements through the landscape involving dispersal and routine movements within home-range or territory are one of the basic but due to a high mobility of birds also one of the least understood processes of bird ecology, especially on the interspecific level. Not only is dispersal a fundamental mechanism of species' spreading into new areas, but also, together with home-range size, it shows the scale on which species perceive the landscape and how they can deal with habitat changes. Dispersal ability, represented by dispersal distances, is determined by a few species specific traits like body size, migratory status, wing and bill morphology, diet type, preferred habitat type or some life-history traits. On the contrary, home-range size variability is determined primarily by energetic demands of the species, given by its body size and trophic level, and by the productivity of the environment. There is a positive relationship between home-range size or territory size, respectively, and dispersal distances of birds that can be attributed to species vagility or their spatial requirements determined especially by their food preference. Nevertheless, further research mainly on interspecific level is necessary for a deeper insight into this issue.
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Landscape structure, habitat properties, species traits or chance: What determines distribution of grassland plants in abandoned fields?
Knappová, Jana ; Münzbergová, Zuzana (advisor) ; Hájek, Michal (referee) ; De Bello, Francesco (referee)
Semi-natural grasslands are among the most threatened habitats in Europe, endangered mainly by cessation of former management practices and conversion into other types of land use. Extensive research has been carried out in European grasslands in last decades, to explain origins of diversity and to provide guidelines for its conservation. However, the very slow response of perennial plants to landscape changes often impedes to accurately evaluate why species occur just where they occur and not elsewhere. Abandoned fields are perceived as potential habitats for species from declining grasslands. Indeed, many species are able to spontaneously colonise abandoned fields, but many other species are absent from communities that develop there. An important question remains what limits their successful establishment. By answering this question, we can gain also important insights into factors determining species distribution in grasslands because colonization of recently abandoned fields by grassland species is the ongoing process which is not obscured by historical changes in landscape structure. The very basic aim of this thesis was to evaluate the status quo of dry grassland plants in fields abandoned in last two decades. And in the second step, to identify what are the main constrains of successful...
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The effect of habitat continuity and management on species composition and diversity
Hubáčková, Barbora ; Münzbergová, Zuzana (advisor) ; Mudrák, Ondřej (referee)
Semi-natural grasslands of the eastern Moravia have big potential to host species-rich plant communities. However, changes in land-use during the second half of the last century were rapid and vast and many grasslands had been ploughed over. In the early 80s some arable lands were sown with low diversity clover-grass mixture and transferred back to grassland. Restoration of grasslands on former arable fields is a major challenge. Their colonisation by grassland species may be complicated by initial seeding productive low diversity seed mixtures. The aim of this study was to estimate differences in species composition and species diversity between ex-arable artificially seeded grasslands and fragments of grasslands with continuity over 70 years in the north part of White Carpathian Mts., SE Czech Republic and identify species traits limiting species ability to colonize the ex-arable grasslands. Target plant species (total of 137) were surveyed on 66 grasslands. Surveyed grasslands were according to continuity and type of management. Coordinates of centroids from each polygon (i. e. surveyed grassland) were used to treat the spatial correlation of the surveyed grasslands. The effect of continuity on species composition and diversity was tested after accounting for differences in the management and...
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Ecological and ethological aspects of bird-building collisions
Semeráková, Anna ; Sedláček, Ondřej (advisor) ; Koleček, Jaroslav (referee)
Collisions with artificial structures represent one of the most significant cause of bird mortality worldwide. Accounting for hundreds of millions bird deaths each year, bird-building collisions represent a particular problem. Although the bird's vision system is perfectly adapted to the orientation during fast flight, birds are often confused due to the transparency or reflectivity of the glass. Moreover, light pollution of urban areas interferes with the physiological geomagnetic and polarized light compass in birds, which causes the night migrants to disorient. The bird-building collision frequency variates in time and space. Throughout the day, largest number of fatal collisions occurs during early morning. Throughout the year, the peak in the numbers of fatal strikes appears in the course of autumn migration. Local species abundance did not appear to be the most important predictor of collision probability. Species traits making birds highly prone to collisions are small body size, high flight speed, long distance of migration and feeding strategy requiring rare and temporary food sources. Aggressive males during the mating period and inexperienced post-fledging juveniles are among the most vulnerable individuals. Based on taxon-specific ecological traits, some bird families were identified to...
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Bird diversity and life-history patterns along gradients of productivity and its variation
Tószögyová, Anna ; Storch, David (advisor) ; Remeš, Vladimír (referee) ; Field, Richard (referee)
Geographical variability in species richness and life-history strategies shows remarkable and well-documented patterns generated by various processes that have not yet been fully revealed. However, the pronounced correlation between spatial patterns in species and trait diversity and spatial gradients in environmental conditions indicates that the environment may modulate these processes. The mechanisms related to environmental productivity (energy availability), as a strong predictor of biodiversity, have been hypothesized to explain the cause of these broad- scale biodiversity patterns. Still, there is no consensus in the explanation, as many of the environmental and biotic factors are strongly interrelated. We have derived testable predictions that allowed disentangling the mechanisms responsible for spatial distributions of life-histories and species richness. The patterns in spatial distribution of many avian traits across the striking productivity gradient in South Africa show a slow-fast continuum in life-history strategies. High environmental productivity in tropics may result in stable populations that favour slow life-history strategies; birds can utilize stable food resources - low food seasonality selects for small clutch sizes, long parental care and high juvenile survival. The...
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Vegetation changes of wet meadows in Slavkovský les
Šimák, Martin ; Münzbergová, Zuzana (advisor) ; Hédl, Radim (referee)
This thesis focuses on the changes of vegetation of the wet meadows in Slavkovský Les during past decade. It uses data on vegetation gained from 100 permanent plots. By the analysis of the species composition and diversity it aims to elucidate the changes of the wet meadows over the last ten years. It aims to define, which are declining and which are becoming more common. Applied management should have a great impact on the observed vegetation changes so its effect is studied in the thesis as well. The knowledge of the suitable management should lead to conservation of the local biodiversity. The abiotic environmental factors are important as well as they can influence the species composition. These factors were studied by the application of Ellenberg indicator values on the species present in the study. These changes were compared in time and in a combination of time with a management type. Thus, we should be able to say how the environment has changed in the past decade and whether the type of management has any effect on the changes. Furthermore, the thesis explores whether changes in species composition over time may be explained by species traits. The results indicate that the species diversity and composition have indeed changed during the past decade. Apparently, the higher amount of...
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Geographical variation in functional traits of European birds
Kopsová, Lenka ; Hořák, David (advisor) ; Remeš, Vladimír (referee)
Each species has specific adaptations to its environment, and since environmental parameters reveal geographic trends, it is reasonable to expect the existence of geographic trends in species characteristics as well. The aim of this study has been to evaluate the effect of environmental conditions on geographic variability of functional traits of European birds. I have analysed the effect of temperature, precipitation, productivity, altitude and habitat type (forest, open habitats, bush, settlements, wetlands) on clutch size, number of clutches per breeding season, egg size, incubation length, age of maturity, body mass, wing, tail, bill and tarsus length. I have used data from the European breeding bird atlas, so that I have calculated mean values of all the traits for quadrats 50x50 km, and then related them to environmental characteristics using OLS and GLS. Clutch size increases with temperature, whereas the number of clutches decreases with it, indicating possible trade-off between clutch size and the number of clutches, whose result is determined by the length of breeding season. Egg size decreases with temperature, possibly due to higher survival of large eggs (and consequently juveniles) in cold regions. Incubation length increases with both temperature and environmental productivity,...
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Relationships between functional traits, home range sizes, and dispersal abilities in birds
Holubová, Kateřina ; Storch, David (advisor) ; Sedláček, Ondřej (referee)
Avian movements through the landscape involving dispersal and routine movements within home-range or territory are one of the basic but due to a high mobility of birds also one of the least understood processes of bird ecology, especially on the interspecific level. Not only is dispersal a fundamental mechanism of species' spreading into new areas, but also, together with home-range size, it shows the scale on which species perceive the landscape and how they can deal with habitat changes. Dispersal ability, represented by dispersal distances, is determined by a few species specific traits like body size, migratory status, wing and bill morphology, diet type, preferred habitat type or some life-history traits. On the contrary, home-range size variability is determined primarily by energetic demands of the species, given by its body size and trophic level, and by the productivity of the environment. There is a positive relationship between home-range size or territory size, respectively, and dispersal distances of birds that can be attributed to species vagility or their spatial requirements determined especially by their food preference. Nevertheless, further research mainly on interspecific level is necessary for a deeper insight into this issue.
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