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Ecological traits as a correlates of spatial variation in abundances of a Czech birds
Farkač, Jan ; Hořák, David (advisor) ; Reif, Jiří (referee)
Jan Farkač, Diplomová práce 2018 Abstract Bird species differ in their local densities, which seems to be related to their geographical distribution and species-specific traits. Investigating such a relationship can help us to understand better how the birds inhabit the space. The aims are as follow (i) to take an alternative approach to densities by counting them just in species preferred habitats and (ii) to explain the abundance characteristics such as an absolute density, variation in local densities or occupancy by species-specific traits. The relationship between abundance characteristics (local densities and their coefficient of variation in space) and avian traits such as a habitat specialisation, diet specialisation, PCA of morphological traits, PCA of reproduction traits - as an estimate of slow-fast continuum and a range size were tested using GLM. There are two abundance characteristics significantly related to species specialisation index. I have used the data from the Common Bird Monitoring Program run in the Czech Republic by the Czech Society of Ornithology. Due to the highest amount of records I have selected data from the year 2009 and subsequently species occupying more than 50 transects (out of 129), which resulted in inclusion of 47 species into analyses. This thesis contains...
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Long-term population trends of birds in North America and Europe: a metaanalysis of existing studies
Říhová, Jana ; Reif, Jiří (advisor) ; Voříšek, Petr (referee)
Since the beginning of the last century there have been significant changes in the environment, farming and the landscape structure. Because birds are one of the longest- studied groups of organisms and are considered to be good indicators of environmental quality, it is advisable to relate environmental changes to changes in bird abundance. Understanding these relationships enables better and more accurate formulation of conservation plans and priorities, and therefore a large number of studies were dedicated to them. Although these studies achieved great progress in the knowledge of the most important factors that affect bird populations, their findings remained somewhat incomplete and fragmentary due to their limited temporal and/or spatial coverage. Therefore, it was not entirely clear which patterns are general and which are confined to some specific regional conditions. The fill this knowledge gap, I collected all studies on long-term trends in bird abundance in Europe and North America, which I was aware of, and made a meta-analysis of their results. Using linear mixed-effects models, I found a significant decrease in open-habitat species, probably as a result of agricultural intensification and abandonment of agricultural land. This pattern was consistent regardless of region or time period...
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Ecological traits of vertebrates along elevations
Schovánková, Hana ; Hořák, David (advisor) ; Kubička, Lukáš (referee)
Animals that live in different altitudes are exposed to different environmental conditions. Among others, ambient temperature, precipitation and availability of resources change along an elevational gradient. An adaptation of vertebrates to these conditions causes that in populations or species that live in higher altitudes individual ecological traits evolves to a different degree than in those that live in lower altitudes. Studies suggest that vertebrates that live in higher altitudes usually have shorter active and breeding season, reach larger body size and weight, have slower growth, have smaller clutches or litters, mature at later age and live longer. However, almost in all traits we can find opposite trends. In all vertebrate groups similar changes in traits occur. However, some traits aren`t explored in all groups, for example grow of birds and mammals. Powered by TCPDF (www.tcpdf.org)
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