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The Effect of Presence and Abundance of Parasites (Nomada, Stylops) on the Host Species Population (Hymenoptera: Andrena) at the Level of Entire Communities
Bureš, Vít ; Straka, Jakub (advisor) ; Libra, Martin (referee)
Bees (Anthophila) play a crucial role as pollinators, vital for maintaining biodiversity in ecosystems. However, the decline in pollinator populations in recent years raises concerns about ecosystem stability. This study investigates the impact of parasitism on host bee populations of the genus Andrena as a potential factor influencing the decline of insects. Additionally, it examines populations of parasites of the genera Stylops and Nomada as indicators of host population status. Bees of the genus Andrena are abundant in the western Palearctic and are commonly parasited by Stylops and Nomada. Leveraging a large dataset from Europe, this study uses abundance data to explore the influence of abiotic and biotic factors on the parasitization rates of host Andrena bees. Specifically, the effects of abiotic factors such as altitude, habitat type, annual rainfall, and average temperature on the parasitization rates by both parasite types has not been confirmed. The results indicate that within small geographical units (sites), larger populations of host Andrena bees are more heavily parasitized by Stylops compared to smaller populations, while this trend does not hold true for Nomada. Interestingly, this study reveals that Stylops and Nomada coexist within the same host populations without competing for...
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Habitat selection in post-breeding temperate forest birds
THRIKKADEERI, Karthik
Habitat selection of forest birds in Branišovský les, České Budějovice, Czech Republic was studied by observing habitat preferences in the non-breeding season and exploring possible shifts in preferences due to the changing seasons. Patterns of habitat selection were analysed at multiple levels: considering all bird species as well as comparing between two feeding guilds. Preferences were also studied by specifically monitoring predation rates by birds on artificial caterpillars and exploring changes with habitat and season.
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Ecology of ants along elevational rainforest gradients in the tropics
MOSES, Jimmy
The thesis investigates the community ecology and species diversity of tropical ants on tropical mountains. The primary focus is on the changes in the ground-dwelling ant communities along elevational rainforest gradients, and how their elevational patterns are influenced by various biotic and abiotic factors. First, we investigated how elevation, leaf litter depth and their interaction affect the abundance, species richness and composition of ground-dwelling ants on Mt. Wilhelm (Papua New Guinea). Next, we investigated how ant communities change with forest succession in time along an extensive tropical elevational gradient in Southern Papua New Guinea. The aim was to assess both spatial and temporal trends in the ant communities and whether these changes could serve as indicators towards ecological recovery after human-induced forest disturbance. Finally, we assessed the relationships of ant species richness and activity, and their relative use of six nutrients, with elevation and season in three different tropical mountain regions (New Guinea,Tanzania and Ecuador).
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Community structure and diversity of corticolous algae in micro- and mesoscales
Štifterová, Anna ; Neustupa, Jiří (advisor) ; Hrčková, Kristýna (referee)
This diploma thesis was focused on the community ecology of corticolous subaerial cyanobacteria and algae. Altogether 54 morphotypes were identified on the surface of the tree bark in the Nature Reserve Březina in České středohoří Mts., Czech Republic. Compared to publish data on tropical and subtropical habitats, high morphological diversity of these organisms in a temperate region was thus recognized. Coccoid green algae - most of them belonging to the class Trebouxio-phyceae - dominated. In a study focused on the algae community structure at small spatial scales (such as a single tree trunk), the temporal factors were found as the most important factor influencing the species composition. The height of a sample on trunks and type of bark roughness seemed to influence the species richness, yet the differences were not significant. The alpha-diversity and species composition of corticolous algal communities among individual trees were strongly influenced by host tree species. The pH of the bark surface also had significant impact on species composition. Generally, trees with lower pH of the bark surface (alder, spruce) had lower species richness, whereas trees with more alkaline bark surface (ash, beech, maple) had higher alpha-diversity values. Considering the generally efficient dispersal ability of...
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Effect of urban gradient on composition of bat communities in Central European landscapes.
Kočí, Jakub ; Lučan, Radek (advisor) ; Andreas, Michal (referee)
Bats (Chiroptera) are usually considered as a group greatly endangered by destructing their habitats through the human activity. However, a significant part of bat species at the central Europe use human buildings as shelters, moreover the natural shelters are marginal or unknown in several species. Considering the linkage of the great part of our bat species to the fragmented area and in connection with a long term human influence on the central european landscape we ask whether at least part of our species see human activity through providing proper shelters as positive. Based on the analysis of landscape structure and ruggedness effect on density, diversity and population structure of bat assamblages acquired by standardized mist net captures located in lowlands (elevations below 500 m) of Czech Republic (204 localities, 3585 bats, 22 bat species), we found that even though most of reactions were species specific and few species seemed to be positively associated with urban environments, most of the bat species rely on the broad-leaved forest cover and other natural habitats such as water bodies. The most significant factor influencing sexual segregation for bats was ruggedness of surrounding landscape. Keywords: Bats, Chiroptera, fragmentation, Europe, temperate zone
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Diversity of traits of aculeatan hymonopterans in habitats with finely-grained substrate
Wofková, Gabriela ; Tropek, Robert (advisor) ; Šlancarová, Jana (referee)
Natural habitats of aculeate hymenopterans are rapidly decreasing and strictly specialized species are thus going to be endangered or extinct. However, in the last decades the conservation potential of postindustrial sites has been found. There were many endangered and nationally extinct species recorded along with the drift sand specialists. However, one unclear thing remains - on postindustrial sites there were still no recordings of species that have similar biological traits to the species that are colonizing these sites. The main target of my thesis was to find traits which make it possible for the insects to colonize postindustrial sites. A matrix of 79 traits was made to describe aculeate hymenopterans biotope preferences, phenology, morphology, biogeographical area, nest, food and life history strategies. With these traits I describe 351 species systematically collected on twenty-one localities with finely - grained substrate found in Polabi and South Bohemia. These traits were tested with weighted mean abundances on type of substrate (artificial vs. sandy) with GEE analysis and the type of locality (dumping ground of coal combustion, ore and sand sludge vs. sandpits vs. natural sand) with PCoA analysis. A phylogenetic correction was incorporated in both analyzes. My results show that on...
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Community structure and diversity of corticolous algae in micro- and mesoscales
Štifterová, Anna ; Neustupa, Jiří (advisor) ; Hrčková, Kristýna (referee)
This diploma thesis was focused on the community ecology of corticolous subaerial cyanobacteria and algae. Altogether 54 morphotypes were identified on the surface of the tree bark in the Nature Reserve Březina in České středohoří Mts., Czech Republic. Compared to publish data on tropical and subtropical habitats, high morphological diversity of these organisms in a temperate region was thus recognized. Coccoid green algae - most of them belonging to the class Trebouxio-phyceae - dominated. In a study focused on the algae community structure at small spatial scales (such as a single tree trunk), the temporal factors were found as the most important factor influencing the species composition. The height of a sample on trunks and type of bark roughness seemed to influence the species richness, yet the differences were not significant. The alpha-diversity and species composition of corticolous algal communities among individual trees were strongly influenced by host tree species. The pH of the bark surface also had significant impact on species composition. Generally, trees with lower pH of the bark surface (alder, spruce) had lower species richness, whereas trees with more alkaline bark surface (ash, beech, maple) had higher alpha-diversity values. Considering the generally efficient dispersal ability of...
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Exploring the relationship between species richness and intraspecific trait variability.
DVOŘÁKOVÁ, Hana
This thesis was originated as a contribution to the wide range of biodiversity studies published recently. It focused on the little explored importance of intraspecific variability in plant communities. A pot experiment hold in glasshouse environment was designed to observe influence of biotic interactions in mixtures of various species diversity on species functional traits and productivity. Variability of functional traits of individual species was assessed in relation to increasing species richness and the contribution of within-species variance to the total variance of pot communities was evaluated at different richness levels.
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