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Effect of castle ruins on diversity of vegetation in the landscape
Javorský, Tomáš ; Münzbergová, Zuzana (advisor) ; Prach, Karel (referee)
Medieval castle ruins undoubtedly create the face of the Czech landscape. Moreover, the few previous studies on this topic have shown that ruins are unique and extraordinary biotope. This work aims to characterize castle vegetation on thirty examined localities (thirty ruins). Phytosociological relevés and soil samples were collected, soil depth was measured and the cover of individual layers was observed - all of this on three spots on each locality. One of the places covered castle and the other ones the nearby forests (each one was chosen differently than the other). The castle walls were sampled separately. The results show that castles not only increase the diversity of forests by hosting a higher number of species but also by a different species composition - castles have a rather large set of species with high fidelity to ruins areas. Approximately half of the uniqueness of the ruins can be explained by the soil qualities, such as higher pH, higher quantity of calcium and magnesium, the other half remains unclear notwithstanding the usage of various explanatory variables. It is certain that castle ruins are from a biological point of view exceptional, unique and they surely deserve the attention which we owe them so far.
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Habitat requirements and competition between native and invasive Impatiens species
Čuda, Jan ; Skálová, Hana (advisor) ; Prach, Karel (referee)
Three of Impatiens species are widespread in the Czech republic, one is native, two of them invasive. Because all species occur in relatively similar habitats, the question is, whether the invasive species can negatively affect the native species, or even the original can can be displaced. The aim of the thesis was: (i) to compare habitat requirments of the Impatiens species, (ii) to determine if the coexistence of species is possible, (iii) to assess the impact of invasive species to the original species. The investigation was carried out using two sets of permanent plots in 5 localities. In the first set with a total of 84 plots (combinations of occurrence of the three species) site characteristics as tree cover, soil humidity, slope and bare land cover were directly measured and nutrient, light, humidity and soil reaction characteristic assessed using Ellenberg indicator values. The second set contained a total of 45 plots with one of the native-invasive congener pair being removed and the intact controls. Number, cover and height of the plants were assesed. The key enviromental factors determining distribution of the species were soil moisture for I. noli-tangere and I. parviflora, and tree cover for I. glandulifera and I. parviflora. Ellenberg indicator values had poor explanation value;...
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Ecology of butterflies in anthropogenic landscape
Kadlec, Tomáš ; Jarošík, Vojtěch (advisor) ; Prach, Karel (referee) ; Kuras, Tomáš (referee)
The dissertation thesis contains six original papers dealing with an influence of isolation, fragmentation and habitat loss on present cultural and urban landscape. Conclusions are based from studies of one species to those of whole butterfly communities. The first two papers deal with autecology of The Hermit (Chazara briseis) from its last viable population in the Czech Republic. During the last 20 years, it retreated from the republic, and recently it is classified as nearly extinct. The papers point to reasons of the rapid decrease: specialized life strategy and habitat losses. Due to high mortality of long-lived females, this species requires the compensation by high population size in large habitats. The next paper refers to habitat requirements of The Hermits' caterpillars. Local habitat conditions at study sites were noticeably similar to the conditions at German localities, at which this species is now practically extinct. Following two papers study an influence of urbanization on butterfly communities in 25 Prague reserves and parks. The first paper points to diversity changes during 30 years and their causes. Average number of species per site remained the same, but there were detected changes in species composition. Remarkable switching of species composition was observed mainly at large...
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Recovery of a submountainous meadow after cessation of fertilizing
Královec, J. ; Prach, Karel
After fertilisation had stopped in 1989, the average number of species per 1 m2 increased four times in the most fertilised plots. However, the number of species also increased in the unfertilised controls, which we attribute to the observed recovery of the whole surrounding landscape. Species typical of mesic grasslands predominantly contributed to this increase. Spontaneous recovery of previously overfertilised mesic grassland may thus work in central European landscapes if seed sources are available nearby. In such cases, no expensive restoration measures are needed to reduce soil nutrients and/or to sow seeds of target species.
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Aspects of using regional seed mixtures
Jongepierová, I. ; Prach, Karel ; Ševčíková, M.
This paper provides an overview (incl. literature) of activities supporting the use of regional seed mixtures realised in the past two decades in the Czech Republic, mainly in the Bílé Karpaty Mts. However, even though the methods of preparing regional seed mixtures are theoretically well known, hardly any initiatives have been taken to produce regional seed mixtures to date. Therefore active support of seed mixture production is urgently needed in all regions, along with a sound certification system.
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Restoration of grassland ecosystems in present restoration ecology
Prach, Karel
The following conclusions have been drawn. (a) Both degradation and restoration seem to be faster on nutrient-rich than on nutrient-poor sites but the latter may be easier encroached by woody species. (b) Restoration is difficult if water and/or nutrient regimes have changed during degradation. (c) Restoration is easier if target species still occur either at the site itself or in its close surroundings. (d) Some restoration measures can be profitable for one group of organisms and detrimental for some others, thus consultancy among experts is needed prior to the start of the restoration. (e) Long-lasting management and monitoring must be guaranteed. Obstacles to successful restoration are also reviewed. Finally, the need of cooperation between scientists and practitioners is emphasised.
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