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Effect of canopy openning on undergrowth of pioneer forests
Lutišan, Zuzana ; Vojta, Jaroslav (advisor) ; Hofmeister, Jeňýk (referee)
Canopy gaps created by falling or the death of one or more trees in the closed canopy forests are a natural part of the temperate forests in temperate zones. There are studies that describe this disturbing mechanism helpful in forest restoration and regeneration of primary virgin forests. Much more frequent in the forests of the Central European country, however, are secondary forests, which originated in the area after the previous human impact in places that were gradually abandoned and successionally overgrown up to the stage of forest communities. And in this type of forest, I tried to capture the effect and impact on vegetation clearings in the undergrowth. The results, presented in this paper come from the area Doupovské mountains, of the military area Hradiště, where there are fragments of pioneer forests established after the displacement of the population in the 50s of the last century. The goal of this thesis was to find out how these canopy gaps affect species composition and diversity of undergrowth pioneer forests and how important are selected environmental conditions on the composition and diversity of undergrowth vegetation. I was able to show that gaps in pioneer forests create an environment for species that normally don't occur under the closed canopy. Light has a significant...
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The origin of open canopy oak forests in Podborany region
Procházka, Michal ; Vojta, Jaroslav (advisor) ; Mayerová, Hana (referee)
The open canopy thermophilous oak forests are a phenomenon whose origin has not been completely clarified yet. However, they are a valuable source of a biodiversity caused by diversity of microstands which has an irreplaceable role in a landscape of the central Europe. Due to the appropriate protection it is desirable to understand the factors which caused this phenomenon. This review summarizes the current knowledge regarding the factors that support creation and preservation of open canopy oak forests in central Europe. In addition to abiotic factors such as small depth in the soil horizon, there is a large section primarily dedicated to human influence and now, mainly abandoned farming methods. Such methods include coppicing and wood-pasture. The question of the origin of open canopy oak forest is also discussed in the context of the history of farming in the Podborany region where we can still find a few open canopy oak forests. Powered by TCPDF (www.tcpdf.org)
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Fragmentation and homogenization of forest communities in urban areas
Pevná, Tereza ; Vojta, Jaroslav (advisor) ; Prach, Jindřich (referee)
This bachelor thesis deals with issue of fragmentation and homogenization of forest communities in urban areas. The habitat fragmentation could be natural or anthropogenic. The main cause of the habitat fragmentation is currently human activity. We can count urbanization among the most significant of these activities. The extinction is one of the few effects, which is however very significant for the biodiversity of the fragmented habitat. The extinction of species in the fragmented habitat does not necessarily occur immediately. In the fragmented habitat, a decrease in the number of species can take place with some delay. There is another fact connected to the extinction in the fragmented habitat. The biotic homogenization can also occur in the fragmented habitat. The biotic homogenization is distinctive and easily observable particularly in urbanized area. Powered by TCPDF (www.tcpdf.org)
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Landscape factors and their influence on succession and distribution of woody species
Jablonská, Viola ; Vojta, Jaroslav (advisor) ; Tesnerová, Cecílie (referee)
The succession of temperate zone vegetation is a multi-layered process of exchange of plant dominants in which trees play a crucial role. To understand the processes that take place in the context of succession at the level of microhabitats, it is necessary to focus on the wider landscape context. This literature review seeks to answer questions of how factors such as the relief, topography, landscape structure and connectivity of habitat isolation, distance from the source or method of seed dispersal affect the occurrence, distribution and succession of species. The environmental aspects of the landscape are also taken into account and the disturbances that are part of the natural dynamics of ecosystems are briefly discussed. A specific factor is the method of using landscape, known under the term land use. Our handling of space, soil and other natural resources in the country leaves an indelible imprint, which is also reflected in changes in the structures of vegetation.
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Free-ranging herbivores as a dispersal vector for species in abandoned landscape
Lepková, Barbora ; Vojta, Jaroslav (advisor) ; Karlík, Petr (referee)
Endozoochory is an important part of plant-animal relationship. In model area of the Doupov Mountains large herbivore mammals, such as red deer, sika deer and wild boar, act as effective seed dispersers. Out of 282 dung samples 29 719 seedlings of 91 species emerged. The most common species was Urtica dioica (80 % of all seedlings). The amount of seeds in dung as well as species composition were highly dependent on dispersing animal, both showed strong seasonality and differences between two studied localities. Frequency of species in dung did not correspond to their frequency in vegetation suggesting strong preferences of herbivores as predators. However more research is needed to test this hypothesis. Given very high time demands for samples processing beforehand the emergence experiment, the influence of concentration by washing through on seedling emergence and species composition was tested. According to preliminary results more seedlings and species emerge from concentrated samples. However, concentration has no effect on emergence of U. dioica as the most common species. Concentration of samples by running water is recommended for faster emergence in greenhouse conditions. Preliminary results also suggest that the approximation of number of seedlings/species on weight of dry mass is not...
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Interactions between animals and plants in urban forests
Dobešová, Jana ; Vojta, Jaroslav (advisor) ; Horčičková, Eva (referee)
INTERACTIONS BETWEEN ANIMALS AND PLANTS IN URBAN FORESTS ABSTRACT This Bachelor thesis focuses on the influence of big mammals (especially Cervidae, wild boars, badgers and foxes) on herb understory in urban forests. Cities are continuously expanding and thus occupy natural habitats of the animals. Therefore, these animals are habituating in urban forests. The specific conditions of both urban and forest habitats and their influences on animal and plant distribution are mentioned. From the possible influences of animals on herb understory, special emphasis is put on herbivory, which can affect individuals, populations and even whole plant assembly. The influence of trampling, urination and burrowing are also investigated. Finally there is a summary of big mammals' influence in relation to human influences. Key words: Urban forests, herbivory, herb layer, disturbation, nutrients, large mammals
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Influence of military activities on vegetation diversity in Doksy region
Staněk, Ondřej ; Vojta, Jaroslav (advisor) ; Volařík, Daniel (referee)
The thesis focuses on description of specific area of Doksy region, situated in northern Bohemia. This region was affected by fifty years of military management. Vegetation composition, species richness and several environmental characteristics were measured and statistically tested to determine the effect of military area on landscape and vegetation. No significant difference in species richness, but important changes in species composition were discovered. Also the environmental (soil) characteristics of the area were probably changed by the military history of landscape. There were no major changes in Beta diversity uncovered, probably because of different management leading to the same resulting changes applied in the landscape. Also four invasive plant species were found in high numbers present in the area connected with past military land-use.
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The effectt of shrubs on establishment of woody plant species in grazed landscape
Wiesner, Pavel ; Vojta, Jaroslav (advisor) ; Brůna, Josef (referee)
My bachelor thesis is concerned about mechanisms that influence establishment and growth of woody plant species under grazing pressure in the temperate climate region. Based on literature sources it determines and explains individual mechanisms and attempts to merge them into a holistic view of the issues of reproduction, propagation and survival of trees and shrubs in the grazed landscape. In general, grazing affects the course of natural succession and under certain conditions helps to maintain shifting landscape mosaics. In addition, the effects of grazing are retroactively modified by the already existing vegetation mosaics. In this regard, existence of shrubs providing protection to seedlings and saplings against bad environmental conditions and against grazing pressure is important, as they help to change spatial heterogenity of vegetation and to establish the shifting mosaics mentioned above. As the spatial heterogenity and total diversity of vegetation can increase or decrease under influences of many factors, the bachelor thesis also pursues the importance of spatial distribution and intensity of grazing, different commonly grazed species and usual systems of grazing management. Keywords: grazing, associational resistance, cyclic succession, wood-pastures, spatial heterogenity of...
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Vegetation of old fields and its dynamics in relation to changes of arable land in Czech Banat (Romania)
Veselý, Adam ; Kovář, Pavel (advisor) ; Vojta, Jaroslav (referee)
- 4 - Abstract Recent abandonment of arable land close to the Czech villages originated in Romanian area called Banat during 19th century implies new variety of habitats representing old fields of different age. We can observe succesional stages of vegetation variable in plant diversity, in some cases significantly high with a number of plant species valuable from the viewpoint of nature protection. Some of these species were known as common in Czechlands as well, but nowadays are strongly endangered or completely extinct. Among others, the number of pieces of cattle in Banat has been reduced. This is the reason why traditional pastures have been grazed less intensively, especially those situated in hardly available localities (e.g. karst valleys and slopes) and often shared with neighborhood villages (including Romanian ones). The abandonment of arable fields thus facilitates the landuse by the way of more productive pastures with better availability from the villages. Next steps of secondary succession and the lost of traditional cycle of the land cultivation sparse shrubs are becoming an important part of the old field vegetation structure, which moreover have a strong influence on the potential restoration of forest ecosystems. The main aim of this thesis is to asses the process on the abandoning of...
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Methods for studying of free-living herbivores zoochory
Lepková, Barbora ; Vojta, Jaroslav (advisor) ; Pokorná, Adéla (referee)
Epizoochory as well as endozoochory are well known dispersal mechanisms. This topic is being studied more and more often lately but our knowledge is still incomplete. The traits of plants dispersed this way are not yet well investigated and there is a gap in knowledge of mutual interaction between plant and animal species during transport. The impact of transport itself especially in endozooochory is also poorly known. We study endozoochory most often using seedling emergence method for seeds contained in dung. Feeding experiments are an interesting way of research and we use them to learn the survival rates of seeds in digestive tract. The most favourite methods for research of epizoochory are tamed animals and all types of dummies. Various laboratory experiments, for example shaking machine, are also frequently used.
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