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Comparison of reproductive parameters of Central European populations of the critically endangered Hermit butterfly (Chazara briseis)
Štochlová, Tereza ; Sedláček, Ondřej (advisor) ; Kadlec, Tomáš (referee)
The Hermit butterfly Chazara briseis is a species from the family Nymphalidae, inhabiting mostly short-stemmed dry steppes. In Central Europe, it is critically endangered. It is therefore currently the subject of many conservation activities, including reintroductions. In such translocations of individuals, it is important that the native and source populations be as closely related as possible in all respects. Therefore, individuals of two forms of this species, Ch. briseis pannonica (Austrian population) and Ch. briseis bataia (Czech population) were bred and their reproductive characteristics were recorded and the differences between the two forms were observed. During two seasons 5 Austrian and 8 Czech females were successfully bred. The Austrian and Czech populations differed mainly in the timing of adult hatching and the beginning of the laying of eggs by females - Austrian individuals are phenologically shifted to one week to 14 days earlier. Individual populations of the same species may also differ from each other in the presence of Wolbachia pipientis. This bacterium can affect the sex ratio in a population as well as the reproduction behavior of individuals. There was a suspicion of its presence in the Czech population. Therefore, a part of the Czech population was treated with...
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Diversity of bird species along elevational gradient on Cameroon mountains
Dubský, Marek ; Sedláček, Ondřej (advisor) ; Reif, Jiří (referee)
The aim of this thesis is to describe the changes of bird species diversity along elevation gradient on six mounts in Cameroon and nearby Bioko island. The results of the analyses confirm most of the defined hypotheses, especially they show that species diversity declines with altitude and rises with area. The absolutely highest diversity was detected on mount Kupé and mount Cameroon, but above 2100 m above sea level mounts Oku and Manenguba are the most diverse. Other analysis showed that the biggest changes in beta diversity of bird assemblages along altitudinal gradients are on the lowest elevational belts which are on the edges of a degraded habitats and continuous undisturbed forests. Other important changes in bird assemblages happen around altitude 1200 m, where the assemblages of lowland rainforest change to assemblages of mountain forest. Analyses of affinity of bird species to forest habitat showed that the most affined assemblages to the forest are those found on mounts Kupé and Rata. On the other hand bird assemblages on mounts Manenguba and Oku are the one of least affined to the forest biotope. Analysis of habitat generalism and specialism did not show the expected outcome and for clearer results the design of analysis needs to be improved. The results of this thesis contribute to a...
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Biodegradable polymer carriers with structure tailored for increased tumor tissue permeability
Hrochová, Michaela ; Etrych, Tomáš (advisor) ; Sedláček, Ondřej (referee)
Cancer diseases are the most common cause of death over the world. One fifth of death is caused by cancer in the Czech Republic. The big problem in the treatment of cancer diseases are side effects of chemotherapy, which make treatment more difficult for patients. The present bachelor thesis is focused on synthesis and characterization of novel polymer carriers. Polymer carriers can target the cytostatic drug to the tumor tissue and minimize side-effect of chemotherapies. This bachelor thesis is focused on synthesis and physical chemistry characterization of new diblock polymer carriers, specifically carries of docetaxel. Successful synthesis of novel water-soluble polymer precursors and conjugates based on N-(2-hydroxypropyl)- methacrylamide is described and discussed in this thesis. The hydrolytic stability of the synthesized diblock systems was studied in 0,3M phosphate buffer at pH 7,4 simulating the bloodstream environment. It has been successfully verified that the synthesized polymer systems are hydrolytically degradable after fulfilling its role of drug carrier and therefore can be finally excreted from the organism. The effect of the type of oxoacid used for modification of the cytostatic on the release rate of the carried cytostatic from the polymeric carriers was thoroughly evaluated and...
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Alternative reproductive strategies and sexual selection in barn swallow Hirundo rustica
Michálková, Romana ; Albrecht, Tomáš (advisor) ; Sedláček, Ondřej (referee) ; Svobodová, Jana (referee)
Molecular techniques have revealed that avian mating system is more diverse and complex than previously thought. Both males and females can use alternative reproductive tactics to increase their fitness. Here, we have determined the prevalence of conspecific brood parasitism (CBP, 22% of nests), quasi-parasitism (QP, 6.5% of nests) and extra-pair paternity (EPP, 51.2% of nests) in European subspecies of barn swallow (Hirundo rustica rustica). In contrast to EPP and CBP, QP is rare and has been described in only a few bird species. Our data indicate nonrandom QP patterns, suggesting that this tactic can be considered a third alternative reproductive strategy, alongside CBP and EPP. Sexual ornaments are usually assumed to evolve as condition-dependent signals of individual quality. In this context, a positive correlation between the expression of ornamental traits and survival, is expected. Evolutionary theory predicts that females seek extra-pair fertilizations from high-quality (more ornamented) males and EPP has consequently been proposed as a principal protagonist in the evolution of male secondary sexual traits, however empirical evidence in support of the assertion is relatively scarce. Despite decades of research into the role of EPP in sexual selection, the potential fitness advantages for...
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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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Ecological Effects of Climate Change on Snakes
Veverková, Barbora ; Sedláček, Ondřej (advisor) ; Frýdlová, Petra (referee)
Climate change is currently one of the biggest threats that animal species must face. Increasing temperatures cause declines in wildlife populations all around the world. Ectothermic animals might be amongst the most threatened organisms by climate change due to their ecology that makes them dependent on ambient temperature. As ectotherms, snakes will most likely need to adapt to new climatic conditions, or they become extinct. To escape raising temperatures and decreasing precipitation, snakes might shift their ranges and move into more suitable areas. However, snakes have a low dispersal ability, which might lead to range reduction and in some populations even extinction. Climatic changes might affect health and behaviour of snake species as well. Increased temperatures can alter incubation period and embryonic development. Alterations in embryonic development and reduction of incubation period can cause different kinds of malformations, especially in oviparous snakes. These malformations can negatively impact fitness, depending on their severity. Some snake species might also benefit from climate change. Elevated temperatures allow snakes to be more active and, in some cases, even shorten hibernation duration. Snakes are also able to better escape predators in high temperatures than in low...
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Cross-taxon congruence in species diversity in non-forest habitats
Koštíř, Vojtěch ; Sedláček, Ondřej (advisor) ; Tropek, Robert (referee)
Relationships between different groups of organisms are one of the major factors shaping Earth's ecosystems. This thesis analyses correlations in species composition and species richness at different spatial scales. Knowledge of these so-called cross-taxon congruences are crucial for proper nature conservation and management of species-rich localities of non-forest habitats. One of the main aims of the thesis was to find suitable surrogate groups for biodiversity conservation in non-forest habitats. Invertebrates and vascular plants are generally good surrogate groups for biodiversity conservation. For example, ground beetles seem to have good correlations in species richness at large spatial scales. However, their importance deeply declines at small spatial scales. At both scales, the species richness of ants and butterflies positively correlates with general species richness. Vertebrates, on the other hand, appear to be a bad surrogate taxon, except for birds which can be placed into a shopping basket with invertebrates and plants. At small scales, species composition differs with the type of agricultural use at studied localities. Umbrella species can be selected from these specific species communities. Best umbrella species for non-forest habitats are invertebrate herbivores such as butterflies...
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Biodiversity of green roofs
Matoušková, Kateřina ; Sedláček, Ondřej (advisor) ; Šípek, Petr (referee)
Green roofs offer interesting multifunctinaly solutions to many problems at once. In a small area they bring benefits to people and nature. They thermally insulate buildings, improve the local microclimate and reduce the city's heat island efect. Green roofs improve air quality and also help retain water in the landscape. In combination with solar panels and retention tanks, green roofs can contribute to the modern trend of building green - sustainable - buildings. Green roofs can be used for growing food sources and for relaxation as well. Wild plants can spontaneously colonize green roofs and thereby expand their habitats in cities. The plants create habitats for many animals (especially invertebrates) and provide nectar sources to pollinators. Except food habitats, they offer birds habitat for nesting and resting place during their migration. The aim of this thesis was to evaluate the contribution of green roofs to urban biodiversity. At present, howewer, most scientific studies deal with the advantges of green roofs in connection with enviromental protection or the technical side. A small part of the studies examines the biodiversity of green roofs. My goal was to find out which factors influence a biodiversity of green roofs the most and to design an ideal roofs solution with the greatest...
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Effects of grazing on grasslands with the focus on the knowledge from the Czech Republic
Marek, Matouš ; Münzbergová, Zuzana (advisor) ; Sedláček, Ondřej (referee)
This bachelor thesis focuses on the application of grazing management on semi-natural grasslands of Czech Republic. One of the purposes of this thesis is to present the concept of using non-scientific literature and experience of conservation practitioners, the "Evidence based conservation", which serves as an inspiration for this bachelor thesis. This concept acts on the principle of making systematic reviews using a broad spectrum of unpublished sources, including personal observation. This thesis is composed of two parts. The first part is a review of scientifically proven impacts of grazing on biodiversity and its individual parts, primarily the plants. The second part focuses on knowledge and opinions of conservation practitioners, who are interested in grazing management. This thesis presents different ways of grazing management, particular grazing problems and their solutions. It speaks about the importance of communication with the general public, which is an often underestimated factor. In this thesis, the grazing conservation is divided into two fundamental elements, the applicating part and the institutional part, which are here also compared. Another aim of this thesis is to analyse the current condition of grazing management and conservation of semi-natural grassland in Czech Republic...
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Methodological problems of the analyses of insect decline
Chlup, Petr ; Storch, David (advisor) ; Sedláček, Ondřej (referee)
In recent years, several studies reporting a severe decline of insect populations across several continents turned the spotlight on the problem of insect decline. However, the reported declining parameters may vary, and it is necessary to differentiate between declines in biomass, abundance, diversity, or geographical range reduction. This thesis aims to summarize how the conclusions about insect decline are shaped by the methods researchers use, especially by the variables they measure, emphasizing the potential methodological issues and limitations of the various facets of insect decline. Furthermore, we offer a brief digest of the most relevant potential biases and interpretative risks threatening population monitoring surveys. The review also provides concise insight into the state of knowledge on the matter of insect population trends. Keywords: insects, insect decline, insect population trends, methodology, methodological issues
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