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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Srážko-odtokové vztahy v povodí Klabavy / Rainfall-runoff relations in the Klabava catchement

Kadeřábek, Michal January 2018 (has links)
This thesis deals with rainfall and water runoff regime in the catchment area of river Klabava. The aim of this thesis is to find changes in the rainfall-runoff regime during the period of observations (1950-2014) and if so, were these changes caused by climate changes or human activities. The research part includes description of rainfall-runoff process and Klabava catchment area description. In the applied part there is an analysis of precipitation - runoff regime for long-term time series of average and minimal annual, monthly and seasonal discharges and annual, monthly and seasonal precipitations using single and double mass curves and statistical tests testing absolute homogeneity, relative homogeneity and trend (by Mann-Whitney-Pettit, Alexandersson, Mann-Kendall tests). The tests were performed by freely available software AnClim designed for these purposes. Mann-Kendall test was performed by MULTMK/PARTMK available as a MS Excel macro for free. Plus, there is basic discussion of floods in Klabava river basin and flood seasonality. The homogeneity tests haven't found many changes at all, most of the detected changes concern the minimal runoff time series. The precipitation annual amount was detected with a raising trend, while the runoff time series seem to have no trend at all. Achieved...
2

Disperzní a letová aktivita pakomárů stojatých vod (Diptera: Chironomidae)

VEBROVÁ, Lucie January 2017 (has links)
I first review the significance of dispersal for individuals and populations including the role of the most significant environmental drivers on separate phases of dispersal. Emphasis is put on aquatic insects inhabiting small standing waters. The following manuscript summarizes a quantitative study of diel and seasonal flight patterns of adult Chironomidae in the Cep II sandpit in southern Bohemia. It provides one of the first comprehensive treatments of the effect of weather conditions and seasonality on the flight activity of adult Chironomidae, phenology of most common species and differences between terrestrial and aquatic species.
3

Dynamika obsahu sekundárních metabolitů v rostlinách během vegetační sezóny (Artemisia sp.) / Seasonal variability of plant secondary metabolism (Artemisia sp.)

Koutská, Barbora January 2018 (has links)
Plant secondary metabolites (SM) are widely used by humans in many ways (pharmacy, biotechnology etc.). For making their use even more effective, it is important to know the seasonality of these chemicals in plants and what affect those changes. Three Artemisia species (Artemisia annua, A. absinthium, A. vulgaris) were cultivated during one vegetation season (from April to September 2016). Plant growth parameters and the beginning of their generative stages were observed, and leaf samples were collected regularly. Samples of some plants were collected repeatedly. A generalist herbivore (migratory locust), was used as a proxy for studying changes in plant secondary metabolism during the vegetation season. The results proved presence of defence secondary metabolites in plants except A. vulgaris species where the role of SM in defence was not shown. Levels of SM changed nonlinearly during the vegetational season and were time-dependent. Plant size did not influence the levels of SM in plants. Levels of SM were low at the beginning of the experiment followed by rapid increase and remaining on maximal levels. The plants which lost their biomass repetitively grew slowly and bloomed later than the plants which were clipped only once. A delay trend showing seasonality of the plant SM was not proved. In...
4

Bioakustický obraz netopýřího společenstva: sezonní dynamika netopýrů v Krugerově NP, JAR. / Bioacoustic pattern of a bat community: seasonal dynamics of bat communities in the Kruger NP, SAR.

Staňková, Markéta January 2021 (has links)
Analyzes of bat echolocation calls enable to investigate diverse patterns of bat communities without the need for contact manipulation with individuals. The continuous all-night acoustic recordings provide standardised data open to quantitative comparisons and testing effects of diverse contextual factors upon bat community structure. The multidisciplinary project MOSAIK (Monitoring Savanna Biodiversity in Kruger NP) mapping patterns of variation in savanna communities under different spatial and temporal influences includes bats as one of the model groups. At standardized monitoring points of the project (covering 20 different areas, each containing triplet points differing in access to the water surface: permanent, seasonal and the crests without a water source), all-night acoustic recordings of bats were undertaken over two seasons (using Song Meter recorders SM4BAT). All records were analyzed with aid of Kaleidoscope Pro software and cluster identification technique (with an input database developed by Weier et al. 2018 and Taylor et al. 2020) controlled by manual checking. Multiple comparisons of diverse coenologic variables of the particular samples were performed together with testing effects of associated contextual variables (geographic setting and climatic currents, seasons, vegetation,...
5

Analýza vzniku a vývoje povodní na řece Dyji / Analysis of the Dyje River floods generation and their development

Grecmanová, Iva January 2011 (has links)
3 Analýza vzniku a vývoje povodní na řece Dyji Abstrakt Tato diplomová práce se zabývá výskytem povodní v povodí horního toku Dyje po závěrový profil Podhradí nad Dyjí. Jsou analyzovány povodňové epizody z hlediska jejich vzniku, četnosti výskytu, sezonality, trendu ve výskytu, příčinných povětrnostních situací. K analýze byl použit soubor dat ČHMÚ pro profil Podhradí v období 1934-2010 (maximální měsíční průtoky a povodňové vlny). Dále jsou zhodnoceny fyzicko-geografické poměry povodí a jejich možný vliv na výskyt a průběh povodní. Byla určena dvě období povodňového neklidu v zimě (hlavně v březnu) a podružné období v létě. Zimní povodně vznikají táním sněhu při prudkých oblevách spolu s dešťovými srážkami, letní z trvalých i přívalových srážek. Jako příčinné povětrnostní situace byly určeny zejména západní cyklonální proudění, brázda nízkého tlaku a cyklóna nad střední Evropou. V posledním desetiletí výrazně vzrostl výskyt povodní na horní Dyji i jejich extremita, tři největší změřené povodně proběhly právě v této době. Klíčová slova: povodně, sezonalita povodní, hydrosynoptika, Dyje Analysis of the Dyje River floods generation and their development Abstract This master thesis focuses on the flood events on the upper Dyje River catchment to the Podhradí nad Dyjí profile. It analyses the flood regime, the...
6

Sukcese společenstev nekrobiontního hmyzu na mršinách malých obratlovců se zaměřením na brouky (Coleoptera) / Succession of insect communities inhabiting carcasses of small vertebrates, with emphasis on the beetles

Kadlec, Jakub January 2015 (has links)
This master thesis deals with succession and succession mechanisms of beetles (Coleoptera) on carrions of small vertebrates. As a model sample of small carrion a small mouse of weight 20 grams was chosen. In 2014 two experiments occurred. The first one studied the succession of a beetle community in dependence on seasonality and time of death of the sample. The second experiment was aimed to survey the blocking effect of an early insect succession on the final beetle community composition on carrions. It turned out, that during decomposition of the carrion the overall amount of beetles raised equally to the guild of necrophagous beetles. Change of the species spectrum during succession was not statistically confirmed. On the other hand, the effect of seasonality was clear as during the season the abundance and the amount of species increased. The proportion of trophic guilds changed significantly, necrophagous beetles were the most dominant part of the community towards the end of the season. Equally, the taxonomic composition of the community also changed during the season. The seasonal dynamics of carrion beetles was clear; Nicrophorus vespillo (Linnaeus, 1758) and N. investigator Zetterstedt, 1824 showed their peaks in spring and summer while N. humator (Gleditsch, 1767) and N. vespilloides...
7

Sledování sezonality v zubním cementu zvířat a využití této metody v archeologii / Research of seasonality in the animal dental cement and the use of this method in archaeology

POŘÁDKOVÁ, Kateřina January 2017 (has links)
In the Diploma thesis called "Research of seasonality in the animal dental cement and the use of this method in archaeology", I devote myself to one of the most reliable methods for determining the age cementochronology, or the analysis of increments of the dental cement. By using the method, it is possible to relatively accurately evaluate the age of an individual and to determine the death season, and thus we penetrate deeper not only to problems of palaeoecological conditions of archaeological situations, but also to economical-social relationships of then populations. Cementochronology also allows trace hunting and settlement strategies, i. e. when and for a what purpose the specific site was settled. The Diploma thesis summerizes previous knowledge about the method and compares it with the results obtained by the analysis of increments of the dental cement, which was applied on referential zoological and archaeozoological material.
8

Vtáčie spoločenstvá pozdĺž výškového gradientu na Kamerunskej hore z pohľadu odchytových dát / Bird Communities Along the Altitudinal Gradient on Mt. Cameroon: Perspectives from Mist Nets

Petruf, Miroslav January 2019 (has links)
in English Mt. Cameroon is a hotspot of diversity and endemism in Africa. Recent research of avian bird communities along the elevational gradient on Mt. Cameroon based on point counts has shown low-elevation plateau of species richness. At the same time, range-restricted montane populations of birds on Mt. Cameroon are unusually abundant if compared to lowland species. I analysed data on community composition, species richness and abundance of birds using an alternative quantitative method - 200 m of understory mist nets erected for three consecutive days across seven elevational plots along the forested gradient of the Mt. Cameroon. First, I looked at the technical limits of this method and confirmed the general opinion that they are better at detecting small birds below 33 g, and that they mostly detected fewer individuals after the first day and always detected fewer new species after the first day of mist-netting. Mist nets detected high proportions of ground-feeding and understory birds and low proportions of birds foraging in higher strata in the lowland forest, which has a scarce understory and a dense canopy. Mist nets recorded similar proportions of birds foraging in all forest strata in the vastly open mid-elevation forest, which has a dense herbaceous understory. They detected higher...
9

Hnízdní a zpěvní aktivita ptáků afrotropického deštného lesa podél gradientu nadmořské výšky / Breeding and singing activity of rainforest birds along an elevational gradient in tropical Africa

Zenklová, Tereza January 2016 (has links)
Tropical areas are usually expected to be a stable environment when compared to the temperate zone. This is true especially for the temperature and the day length which ensure relatively stable food supply. As a consequence, tropical birds, especially rainforest species, are thought to breed all year round. But even in the tropics, breeding can be synchronized with some fluctuating environmental conditions such as rainfall and differences in food supply and breeding and singing activity may occur seasonally in tropical rainforest as well. But the data for testing these assumptions are still scarce. In the first part of my thesis, I focused on the seasonality in breeding activity in various feeding guilds of birds inhabiting tropical rainforest on Mount Cameroon in three different elevations - lowland, submontane and montane forest. The second part focuses on the seasonality in singing activity at both population and species level. I also compared singing activity with the data on breeding activity. The extent of breeding activity differed between feeding guilds and I showed preferences of different guilds to different seasons for breeding. Most of the groups, especially insectivorous birds, bred in the beginning of the dry season, except of species searching for invertebrates on the ground. These...
10

Využití bioakustických přístupů pro studium interakcí druhů a druhové bohatosti ptačích společenstev / Application of bioacoustic approaches in investigation of bird species interactions and community species richness

Vokurková, Jana January 2021 (has links)
Birdsong is one of the most fascinating communication tools in the animal kingdom, whether it is used for attracting a mate or in territory defense. In my dissertation, I present evidence that we can successfully study the role of birdsong in territorial behaviour, its seasonal variability, and ultimately its role in evolutionary processes thanks to modern bioacoustic and ecoacoustic approaches. By combining the bioacoustic approach with molecular analyses, I demonstrate that in the model system of two closely related passerine species, the heterospecific song convergence in their secondary contact zone is based on cultural transmission, and not on interspecific hybridisation and/or gene introgression. My dissertation further extends into the tropical zone, which is generally characterized by less pronounced environmental seasonality compared to the temperate zone. The study of potential seasonality in singing activity and the proportion of vocalizing species in this zone therefore requires year-round monitoring, which is possible thanks to the quite recent development of automated recording units (ARU). First, we confirmed that using ARU provides very similar estimates of community composition, species richness, and abundance to traditional field methods (point counts) in the specific conditions...

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