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Selected impacts of climate change on birds in European mountains: shifts in altitudinal distribution, population changes and changes in phenology
Mikulcová, Eliška ; Reif, Jiří (advisor) ; Hološková, Adriana (referee)
Many studies focused on the impact of the climate change on organisms including mountain birds. Mountain birds are particularly threatened by the impact of climatic change because they occur in an extreme environment. Climate change impacts mountain birds through increasing temperature, which affects their altitudinal shifts and abundances. These two variables depend also on species-specific traits, distribution area and habitat change. This thesis aims to sort knowledge about impacts of climate change on mountain birds and to explain the variability of altitudinal shifts of these species. Species occupying lower altitudes, open habitat species and short-lived species showed the biggest upward shifts. Downward shifts occurred when the impact of habitat change outweighed the impact of climate change. No significant shifts were recorded in species that respond to climate change by changes in phenology which likely compensate the adverse climate change impacts without the need of translocation. Population trends were usually negative with the steepest declines in high- alpine species, ecological specialists, long-distance migrants and short-lived species. In order to reduce decline in numbers, it is important to set up effective local vegetation management and globally stick to climate targets. Key...
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Bacterial life history strategies in gamma-irradiated arable soil receiving different microbial inocula
FARKOVÁ, Karolína
Soil contains an extraordinary level of microbial biodiversity that supports key ecosystem functions. Understanding how soil microbial communities assemble in agricultural ecosystems, as well as what traits they exhibit (i.e., what functions and services they mediate), is essential to better predict the consequences of biodiversity loss. This thesis analyzes the composition, diversity, and life history strategies of soil bacterial communities after the introduction of microbial communities from different sources (i.e., soil and cow excreta) into sterile soil (-irradiated). The results show that bacteria from soil and excreta successfully established in the -irradiated soil and that the bacterial composition and diversity strongly depends on the inoculation source. Analyses of selected functional traits proved that early colonizer taxa were characterized by having higher 16S rRNA copy numbers, smaller genomes and elevated motility and sporulation abilities than the original soil bacterial community. In addition, despite the soils showing similar initial physicochemical and biochemical properties, the different bacterial assemblages generated strong differences in soil properties and microbially-mediated functions. This thesis contributes to a better understanding on how the composition of microbial community is important for the microbial biodiversity in soil and in turn, how biodiversity can contribute to changes in soil fertility and bacterial activity through different life history strategies and traits.
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The biology of aging in Nothobranchius fishes
Žák, Jakub
The aging human population and consequent unprecedented demographic changes in society have inevitably led to more scientists focusing their research on aging. Senescence, in the narrowest biological sense, is age related decline in an organism's function and survival. The majority of senescence research is performed in the laboratory environment. The basic biology of wild counterparts of model organisms is therefore relatively unstudied, despite its importance for proper interpretation of laboratory outcomes. This dissertation, via a series of 6 first-authored and 5 second-authored papers, combines field and laboratory research on senescence and senescence-related life history traits using a short-lived fish Nothobranchius furzeri. An age at the maturity of 14 days post hatching in wild N. furzeri is presented in this thesis as well as extremely fast growth of wild fish. Both life history traits have important consequences for senescence. The following section is focused on how the environment modulates senescence. In the first step, preferred body temperatures of Mozambican Nothobranchius fish were measured and descriptions of environmental and behavioural fluctuations within a 24 hours periodicity were completed. Based on this knowledge, ecologically relevant thermal fluctuations were simulated...
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Plant responses to deer browsing and the consequences for further browsing
Dudlová, Tamara ; Lepková, Barbora (advisor) ; Štenc, Jakub (referee)
(English) The bachelor thesis focuses on the interaction of plants and herbivores, specifically deer. The main question is if (and possibly how) the changes induced in the plants by deer browsing affect the probability of re-browsing. I tried to answer the question by reviewing published literature. Plants respond to browsing by tolerance (compensatory growth) or resistance (production of defensive chemical compounds), depending on the plant's life strategy. Tolerance prevails in adult woody plants and grasses; resistance prevails in young woody plants and forbs. In resistant plants, browsing increases the content of phenolic substances and decreases the cellulose content, while tolerant species react in the opposite way. It is the contents of these substances, which are negatively correlated, that are key to food selection by deer. Large species of deer generally prefer plants with more cellulose, which they are able to digest efficiently. Smaller species prefer plants with lower cellulose content and higher concentration of simple sugars. These more nutritious plants are protected from browsing by phenolic substances, which smaller deer species are able to neutralize more effectively. Only a few studies have addressed the issue of re-browsing of the same plants, and their results are ambiguous....
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Lipid composition of biological membranes and life-histories in songbirds
Šimonová, Kateřina ; Tomášek, Oldřich (advisor) ; Sam, Kateřina (referee)
Differences in the composition of cell membranes are considered to be the physiological mechanism responsible for different metabolic rates, life span and consequently, different life-histories. The membrane pacemaker theory suggests that higher membrane unsaturation may be an important factor responsible for higher metabolic rate and shorter life span of organisms. The alternative hypothesis, on the other hand, assumes that membranes can function as structural antioxidants, and thus that higher membrane unsaturation may be associated with longer life span. The aim of this work was to test how changes in the fatty acid composition of membranes depends on body size, latitude and altitude, within which different life-histories and metabolic rate were observed. Temperate and tropical lowland songbird species were chosen for the models testing the effect of latitude, and only tropical species of songbirds were chosen for the models testing the effect of altitude. Part of the work was molecular sex determination. Using gas chromatography and mass spectrometry, the amount of individual fatty acids contained in red blood cell phospholipids was obtained from blood samples. The results showed that the composition of the membranes in most cases correlates with body size, which also correlates with almost all...
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Surviving of Northern Lapwing (Vanellus vanellus) chicks in agriculture landscape
Kubelka, Vojtěch ; Šálek, Miroslav (advisor) ; Cepák, Jaroslav (referee)
The variability of egg-size within a bird species reflects different reproductive investments and, besides the intrinsic constraints and particular female quality, it can be affected by environmental factors, too. Moreover, the egg-size predetermines the chick performance. The knowledge of factors influencing precocial chick survival is crucial for better understanding of life-history strategies as well as for endangered species conservation. The Northern Lapwing (Vanellus vanellus) represents a suitable model species for investigation of climate variables effects on egg-size and also to study factors influencing chick survival. Eggs in a total of 714 nests were measured during 13 breeding seasons over period 1988-2014 in South Bohemia and 293 lapwing chicks from 100 broods in 37 localities were monitored in 2013-2014. The mean egg-size through the whole season is positively affected by March precipitation, March clutches also negatively by minus temperatures in March. The higher intensity of rainfall there is during March, the bigger eggs are laid in March and the steeper is slope of decline in mean egg-size during season. This decline is more profound with lower rainfall in April. The effect of habitat is not significant. The body mass and condition of hatchlings is positively correlated with the...
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Oxidative stress and condition-dependence of ornamental signals of quality in socially monogamous songbird
Valášek, Stanislav ; Tomášek, Oldřich (advisor) ; Sedláček, Ondřej (referee)
6 ABSTRACT Conditional ornaments plays irreplaceable role in sexual selection in non-small part of by sexual reproduction reproducing animals. Fastidiousness of generating and later also carrying of these ornaments which show condition of their wearer, burdens also metabolism in non-small scale. This thesis tests hypothesis of mutual addiction between conditional ornaments, as the indicators of qualities of individuals and metabolism, as the most significant source of free radicals which are responsible for oxidative stress. The real weight of influence of ornament fastidiousness on organism, resp. on redox state, is tested in this thesis. Manipulations which were performed with individual males of model species should point how much the selected factors correlate each other. The barn swallow (Hirundo rustica) is the model species. Analyses of dates collected during trapping which were realized in breeding seasons in 2012 and 2013 does not show any important trends between observing variables. This fact is confirmed by minimal differences and inconsistent variability of levels of measured antioxidants - oxidoreductases, superoxide dismutase and glutathione peroxidase. The marginal effect of manipulations with one of the conditional ornaments which are presented in model species supports the hypothesis of...
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