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Nutrient budget in reclaimed and non reclaimed heaps
Veselá, Monika ; Frouz, Jan (advisor) ; Svoboda, Miroslav (referee)
Extraction of mineral resources causes landscape degradation and the aim of reclamation efforts is to restore ecosystems. Our research was carried out on spoil heaps after brown coal mining near Sokolov (Czech Republic). We compared twenty years old spontaneously developed sites and reclaimed sites afforested by alders Alnus glutinosa and A. incana. Biomass and nutrient budget were evaluated for herbs and woody plants, separately for species Salix caprea, Populus tremula and Alnus glutionosa. Alder showed significantly higher concentrations of nitrogen and carbon compared to other tree species. The total amount of biomass, carbon and nitrogen was higher on reclaimed sites whereas phosphorus was more represented on spontaneously developed sites. Most of nitrogen was accumulated in the below-ground tree biomass and the largest amount of phosphorus was in the above-ground tree biomass. Woody plants of non-reclaimed sites produced more litter whilst litter of alder stands showed a higher concentration of nitrogen. Higher values of biomass, carbon and nitrogen of reclaimed sites were probably achieved through alder ability to fix atmospheric nitrogen.
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Struktura společenstev hálky tvořících členovců na vrbách
KADLEC, Jan
In this thesis, I examined ecological factors that affect diversity and abundance of galls on willows. I focused on the effects of host-plant phylogeny, host-plant defences, and the effects of interactions among herbivorous guilds. I show that gall abundace is mainly affected by host-plant nutrients, while the defensive traits have only marginal effect. The effect of host-plant phylogeny seems to differ betwen groups of gall-forming arthropod taxa, with several of gall forming species on willows being polyphangous and showing only limited response to willow phylogeny. On the whole, the response of gallers largely differes from the response of less specialized guilds of herbivores.
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Vliv duální mykorhizy na příjem těžkých kovů vybranými dřevinami čeledi Salicaceae
Kuchár, Michal ; Mrnka, Libor (advisor) ; Kolaříková, Zuzana (referee)
3.2. Abstract Soil contamination by heavy metals represents rather serious environmental problem for both human health and an environment itself. One of the perspective technologies dealing with this threat that only recently has been intensely developed is phytoremediation by means of short rotation coppice plantations. As plants used in this technology (mostly poplars and willows) host two major groups of mycorrhizal fungi substantially influencing plant physiology it is important to study plant-mycobiontheavy metals interactions rather than just plant-heavy metals interactions. The present thesis aimed to contribute to the growing knowledge of the field by search for suitable mycobionts of poplar or willow tolerant to heavy metals, by evaluating an activity of the key antioxidative enzyme in selected mycobionts and by looking at physiological responses of plant hosts to their mycobionts in a soil polluted by heavy metals. The first experiment in vitro focused on screening of morphometric criteria of fungi growing on solid growth media amended with mixture of heavy metals. Based on the results, several tolerant ectomycorrhizal strains were chosen for the next inoculation of fast growing trees serving phytoextraction and phytostabilisation strategies. The second, re-synthetic experiment was conducted in...
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Specificity of insect-plant associations and their role in the formation of plant defenses and speciation
VOLF, Martin
The aim of this dissertation is to investigate what role insect-plant interactions play in the formation of host-plant defenses and in the diversification of both groups. We show that various groups of herbivore respond differently to host-plant defenses. Therefore plant defenses diversify into suites of complementary traits, as individual traits fail to provide protection against specialized herbivores. Further, we identify what levels of host-phylogeny shape the food-web structure of insect herbivores. We show that specialized herbivores are affected mainly by the terminal parts of the host-phylogeny. In contrast, more polyphagous guilds are affected mainly by the mid-levels of the host phylogeny because the effects of terminal or deeper phylogeny seem to be surpassed by other factors in more generalist insect species. In the last chapter, we show how specialized insect-plant interactions generated by tight insect-plant coevolution can influence the speciation in plants over environmental gradients.
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Insect herbivores drive the loss of unique chemical defense in willows
VOLF, Martin
The thesis examines the effects of chemical and mechanical defensive traits on insects in a local community of 11 Salicaceae species growing in sympatry. The results repeated loss of willow specialized chemical defense. This could be due to its low protective value and high energy costs. Our study thus shows that the balance between costs and benefits of defensive traits is not necessarily in favor of specialized defenses and illustrates a process, which may lead to the reduction in a defensive trait.
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