|
|
Interactions of herbivore funtion gourps and Succisa pratensis
Šulcová, Hana ; Janovský, Zdeněk (advisor) ; Roubíčková, Alena (referee)
Herbivory is one of most important factors which form meadow ecosystems. These ecological communities have one of the biggest variety of species in Central Europe and their research is important in terms of management of protected species as well. Localities which has a similar importance, is also a meadow ecosystem with occurrence of Succisa pratensis, the only host plant for rare butterfly Euphydryas aurinia. Research of Succisa and its other herbivores can improve a protection of this particular butterfly. Effects of herbivores of Succisa were examined by several experiments. The first one was a field cage experiment. Its aim was to detect what kinds of herbivores (rodents and invertebrates) are involved in herbivory of leaf rosettes of Succisa and what is their impact on the fitness of these plants. The intensity of herbivory of Succisa was measured for over two vegetation seasons on the month bases. In this experiment were also examined effects of surrounding vegetation on the studied plants of Succisa. The second experiment was performed in a garden. Its aim was to clarify the role of herbivores of leaf rosettes, stalks and their interactions on the fitness of Succisa. The third experiment was concerned to true bugs, which are pre-dispersal predators of seeds of Succisa. Their effects on...
|
|
|
Preferences of the main groups of pollinators for the functional floral traits
Malá, Karolína ; Janovský, Zdeněk (advisor) ; Hadrava, Jiří (referee)
This bachelor thesis summarizes the preferences of the main functional groups of pollinators towards floral traits of plants. Due to coevolution and mutual selection pressures, these two life forms have begun to adapt to each other and develop traits on which the future of their life depends. The plant seeks to attract its pollinators, thus ensuring efficient pollen transfer or reproduction for its species. Attractants are used to motivate visitors to its flowers. These attractants provide pollinators with either direct rewards (food, shelter, brood) or rewards in the form of sensory perceptions (colour, scent, morphology). Recently, it has become apparent that flower colour, morphology and the type of food reward offered by the flower have the greatest influence on pollinator choice. Based on preferences towards attractants, we can organize several functional groups whose representatives have the same or similar choice preferences. Key words Pollination syndromes, pollinator, selection pressures, plant traits, coevolution, preferences, fidelity, diptera, coleoptera, lepidoptera, hymenoptera, birds, colour, morphology, rewards
|
|
|
Pollination in urban ecosystems
Krygielová, Anna ; Janovský, Zdeněk (advisor) ; Mikát, Michael (referee)
Pollination success in the urban area mainly depends on the characteristics of plant populations and their pollinators, which are determined by the structure and characteristics of the urban ecosystem. Urbanization is a complex and uneven integration of landscape attributes such as habitat fragmentation, a high proportion of built-up area, the often limited size of green areas, and lower connectivity between them. These particular predictors have different effects on plant and pollinator abundance and species diversity. In general, an increasing level of urbanisation reduces the quantity and quality of pollination and therefore negatively affects the reproductive success of plants. On the other hand, in comparison with intensive agricultural landscapes urban areas (especially urban fringes and semi-natural urban areas) can contribute to the diversity, abundance, and reproductive success of plants and the diversity and abundance of their pollinators. This potentially positive influence of the city on biodiversity can be further developed through effective urban planning and appropriate management of existing public and private green areas in the city. Keywords: pollination, urban ecosystems, urbanisation, urban characteristics, urban green spaces, plant-pollinator interactions, plant reproductive success
|
|
| |
|
|
The influences of biotic interactions on population biology of Sanguisorba officinalis
Větvičková, Anna ; Janovský, Zdeněk (advisor) ; Jičínská, Jana (referee)
Plants can interact with many different organisms on many trophic levels in their life. In this thesis I investigated how three biotic inertactions, powdery mildew infection, caused by Podosphaera ferruginea, predispersal seed predation by Dusky Large Blue (Phengaris nausithous) and Scarce Large Blue (P. teleius) and deer grazing affect life cycle and population biology of the Great Burnet (Sanguisorba officinalis L.). I also analysed their preferences of environmental conditions. Most of studied plant populations growth rates (λ) were lower than 1 and population decreased, but quite surprisingly for more populations vegetative reproduction was more important than reproduction by seeds. All intraction mentioned above affects more generative reproduction, and thus their influence on Great Burnet population dynamics is low, even with modelled maximal possible effect. Environment conditions analysis showed that powdery mildew occurs on sites with more flowering individuals, where spreading is very easy, butterflies preferred high, well noticeable flower heads grown high above other vegetation and host ant presence. For host ants' presence model locality was only significant variable.
|
|
|
The role of biotic interactions in population biology of meadow plants
Janovský, Zdeněk
In present thesis, I treat the topic of impacts of plant-animal interactions, namely herbivory and pollination, on plant life cycle and lifetime fitness. First, I identify the components of the impact of plant-animal interactions: i) interaction frequency; ii) per-interaction effect; iii) sensitivity of the plant's life cycle to the changes in vital rate impacted by the animals. Furthermore, I also classify other causes changing the outcome of a plant-animal interaction into two categories: i) plant's traits; ii) plant's environment. A review of extant literature on the topic revealed that especially the role of plant's environment in changing the outcome of plant-animal interactions is largely understudied and I attempt to reduce this gap in knowledge in the five detailed studies encompassed in this thesis. The detailed studies focus on a model system of Central European wet grasslands and especially on three species typical to it: Succisa pratensis, Achillea millefolium and A. ptarmica. The first two studies examine the effects of environment on frequency of plant- animal interactions. The next two studies are more integrative, one focusing on the impacts of different herbivore groups on the complete life cycle and the other on interaction of herbivory and pollination on plant lifetime fitness....
|
|
|
Changes in pollinator behaviour under different plant spatial aggregation
Štenc, Jakub ; Janovský, Zdeněk (advisor) ; Bartoš, Michael (referee)
Plants often occur aggregated into clusters and this spatial pattern is supposed to affect pollinator behaviour and pollen dispersal. Such pollinator reaction may influence reproductive success of zoogamous plant species both in terms of number of available mates and their genetic diversity (nearby growing plant individuals are also often closely related, especially in clonal plants). In the present thesis, I investigated the influence of plant spatial aggregation on pollinator behaviour and how this translates into pollen transfer. For that purpose, I carried three experiments. In the Experiment 1, I used potted plants placed into arrays and aggregated into four patches in order to track the pollen dispersal by means of a UV-dye pollen analogue. I manipulated distances between plants within clusters (dense × loose) and between clusters (near × far). I conducted this experiment for three plant species differing in their pollinator spectra. In the Experiment 2, I observed pollinator foraging sequences (sequences of visited plant individuals) under the same experimental design as for the first experiment, but I carried out this experiment for five plant species. In addition in one study species, Dianthus carthusianorum, I conducted the Experiment 3 to get better insight into pollination effectiveness...
|
|
|
Pollinator pollen carryover effectiveness and plants' ability to enhance it
Freudenfeld, Martin ; Janovský, Zdeněk (advisor) ; Mikát, Michael (referee)
Pollinators carry over pollen from one flower to another. They facilitate plant reproduction. Pollinator functional groups differ in their effectiveness of pollen carryover. Quantity of pollen grains on their body and deposition on stigma are very important. Pollinator carryover capacity depends on its functional traits. Body size, hairiness, visitation behaviour, foraging preferences, flower constancy and abundance of pollinators are significant. Plants can enhance effectiveness of their pollination by adaptations to specific pollinator functional groups. They improve positioning of pollen on pollinators by specific changes to floral morphology, quantity and size of pollen grains. They can also enhance the effectiveness through aggregation of pollen grains into groups or into pollinia or by optimisation of pollen release in time.
|
|
| |
|
|
Pollinator movement and orientation at small spatial scales
Matoušková, Eva ; Janovský, Zdeněk (advisor) ; Tropek, Robert (referee)
Pollination is interesting andcomplex interaction between insects and plants which is essential for a wide spectrum of plants and animals. Hoverflies (Diptera: Syrphidae) and bees (Hymenoptera: Anthophila) are one of the most common pollinators in the Central Europe and are mostly involved in pollination of local plants. To maintain pollination, it is necessary the movement of pollinator from one flower of a specific species to another flower of the same species. This movement is affected by a number of factors based on both the environmental and pollinator traits. The aim of this work is to explore the nature of traits affecting pollinator flight between plants on small spatial scales, to classify the knowledge about the influence of pollinator and ambient effects to compare the differences between hoverflies and bees and suggest further possible fields of research. Keywords: pollination, hoverflies, bees, Syrphidae, Anthophila, movement
|
guest ::
