|
| |
|
| |
|
|
Role of microorganisms in the evolution of reproductive strategies in birds
Novotná, Lucie ; Javůrková, Veronika (advisor) ; Ferenc, Michal (referee)
Microorganisms are ubiquitous and can be found on the body of birds, in avian nests or may be carried into the nest along with nest-lining material. Microorganisms may therefore colonize eggshells of eggs in a clutch and subsequently penetrate into the egg contents. This so called trans-shell infection has been observed to affect hatching success, cause embryo mortality or subsequently influence hatchlings phenotype. Nevertheless, the probability of eggshell bacterial load or trans-shell infection depends on many factors, including environmental conditions, nest type, incubation pattern, and nest-lining material. Furthermore, some modifications of avian reproductive strategies may lead to reduction of negative effect of trans-shell infections, and significantly improve reproductive success. These mechanisms include incubation, mechanical and chemical barriers of egg, eggshell pigments or using of feathers and specific plants as nest lining material. Based on these findings, it can be concluded that the different reproductive strategies in birds should be a result of strong selective pressure caused by microorganisms. Although many recent studies have supported this assumption, research on this issue still suffers from many methodological shortcomings that must be eliminated in future studies.
|
|
|
Spatial correlations in population dynamics of spruce bark beetle (Ips typographus): Example of Mantel test usage
Šimera, Ondřej ; Kindlmann, Pavel (advisor) ; Ferenc, Michal (referee)
Spruce bark beetle (Ips typographus L.) is the most common and abundant beetle from the Scolytidae family in European forests. It is the most important biotic factor causing disturbances and affecting forest ecosystems. Thus, it recently became a subject of discussions, how to manage the forests properly in order to find an adequate equilibrium among economical, turistic and natural values of the forest. Many studies have shown a positive effect of bark beetle outbreaks on biodiversity and natural forest regeneration. It is hard to tell if these outbreaks are regular or not because there are many factors which can elicit them. However, just these factors can help us predict the probability of unforseen population outbreak. One of these methods can be monitoring of surrounding areas because these areas tend to be synchronised. For this purpose, multiple mathematical models can be performed, such as the Mantel test, which determines the correlation between two matrices. Keywords: Spruce bark beetle, Ips typographus, population dynamics, spatial correlations, Mantel test
|
|
| |
|
|
Effect of altitude on avian life histories and physiology
Brindzák, Marek ; Albrecht, Tomáš (advisor) ; Ferenc, Michal (referee)
Vliv altitudy na životní strategie a fyziologické nastavení ptáků Řešitel práce: Marek Brindzák Vedoucí práce: doc. Mgr. Tomáš Albrecht, Ph.D. Abstract The pace-of-life syndrome theory proposed that species with similar life-histories share physiological traits that are more similar than species with different life-histories. Despite the fact that life-histories and physiology are well studied in birds it is still unknown how altitude changes these traits. However, shifts in life-histories across latitudinal gradients, with slow pace characterized by high investment to the future reproduction in tropics and fast pace of life characterized by high to the actual reproduction in temperate, is well know. From this knowledge we can assume how birds solve the trade-of between survival and reproduction based on the environmental conditions. This thesis summarizes effect of altitude on selected life-histories and physiology traits, the findings are compared with latitudinal changes. The first part of thesis is focused on describing latitudinal and altitudinal effect on selected avian life-histories traits. The second part deals with the altitudinal effect on the selected physiological traits in birds. Birds breeding at high altitude exhibit novel pace of life with life-histories similar to a slow pace but with...
|
|
|
Spatial correlations in population dynamics of spruce bark beetle (Ips typographus): Example of Mantel test usage
Šimera, Ondřej ; Kindlmann, Pavel (advisor) ; Ferenc, Michal (referee)
Spruce bark beetle (Ips typographus L.) is the most common and abundant beetle from the Scolytidae family in European forests. It is the most important biotic factor causing disturbances and affecting forest ecosystems. Thus, it recently became a subject of discussions, how to manage the forests properly in order to find an adequate equilibrium among economical, turistic and natural values of the forest. Many studies have shown a positive effect of bark beetle outbreaks on biodiversity and natural forest regeneration. It is hard to tell if these outbreaks are regular or not because there are many factors which can elicit them. However, just these factors can help us predict the probability of unforseen population outbreak. One of these methods can be monitoring of surrounding areas because these areas tend to be synchronised. For this purpose, multiple mathematical models can be performed, such as the Mantel test, which determines the correlation between two matrices. Keywords: Spruce bark beetle, Ips typographus, population dynamics, spatial correlations, Mantel test
|
|
|
Mountains as islands
Kačabová, Petra ; Storch, David (advisor) ; Ferenc, Michal (referee)
In this paper I deal with island biogeography and its applicability to isolated mountaintops, as an ecological equivalent of true islands. I discuss both true and mountain islands regarding their origin and the influence of long-term climate evolution on Earth. I underline some features of mountain islands, resulting from their topography and the dissimilarities of both types of island barriers. I find that mountain and true island communities might or might not have a number of species in a state of equilibrium, caused by balance between species immigration on island and their extinction. If the number of species on island is not in equilibrium, species extinction is not balanced by species immigration. I consider patterns of island communities, mainly nestedness, which has been frequently studied on mountain, as well as true islands. I discuss distribution patterns concerning invertebrates. And finally, I concentrate on recent methods of moutain island research and discuss mountain island isolation issues in terms of global warming.
|
|
|
THE EFFECT OF AN INCREASING COVERAGE OF INVASIVE BLACK LOCUST ON BIRD COMMUNITIES IN FOREST STANDS
Kroftová, Magdalena ; Reif, Jiří (advisor) ; Ferenc, Michal (referee)
Biological invasions are one of the most important threats to global biodiversity and they were also found to negatively affect some bird species. Despite relatively large number of scientific studies dealing with the impacts of invasive plants on bird communities, their results are inconsistent, especially it is not clear how birds respond to increasing levels of expansion of invasive species in native species stands. Moreover, bird responses to plant invasions seem to depend on the ecological characteristics of individual bird species. This study contributes to elucidation of this problem; I investigated the impacts of black locust (Robinia pseudoacacia) invasion on bird communities in three types of forest stands with different levels of invasion: in stands containing solely the native oak (Quercus spp.), in partially invaded stands with different proportions of black locust and oak (mixed stands) and in pure black locust stands. Previous studies that examined birds in pure oak and pure black locust stands have found that they differ markedly in vegetation structure, but not in the total number of bird species. However, habitat specialists were associated with the oak stands, while generalists with the black locust stands. Therefore, I predicted that (1) the total species richness will be...
|
|
|
Forest bird community composition: patterns and their drivers
Birčák, Tomáš ; Reif, Jiří (advisor) ; Ferenc, Michal (referee)
This diploma thesis examines factors that have affect on the forest bird communities in managed and unmanaged forests in the Slovakian mountains Vtáčnik. The research was conducted by a line method based on three different stages of forest succession in pure beech and mixed stands. The highest abundance and species richness was found in the old unmanaged stands. Abundance and the species richness in managed stands at the age of 60 and 90 years did not show any significant difference. In conclusion, this thesis noted that the main factors affecting bird communities were tree height variability, amount of understory and the presence of dead wood.
|
guest ::
RSS feed.