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Pasture of horses as an essential tool in biodiversity conservation
Dudková, Andrea ; Malíček, Jiří (advisor) ; Sedláček, Ondřej (referee)
In recent decades, the approach of active management, preventing overgrowth and simplifying the species composition of non-forest biotopes, has dominated in nature conservation. Dominant plants, suppressing competitively weaker species, are therefore reduced for example by grazing of large herbivores. It turns out that horse grazing has considerable potential for enhancing biodiversity. The aim of this bachelor's thesis was to summarize the main aspects of horse grazing based on literature research and come to a prediction of its future use in nature conservation. Studies on the use of horse grazing in biodiversity conservation show that it works well to suppress competitively strong grasses and supports the presence of flowering dicots and associated insects. The disadvantage of grazing horses is that they do not consume woody plants and thus cannot suppress the growth of bushes. On larger areas (>20 ha), year-round wild horse grazing is used, while domestic horses are suitable for seasonal grazing on smaller sites. Due to the positive results of horse grazing in promoting biodiversity, the more successful suppression of competitively strong grasses compared to other herbivores and the lower level of human effort compared to mowing, it can be expected that cases of using horse grazing in nature...
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The influence of intensity of agricultural land use on pollinator diversity and abundance
Tomsová, Lucie ; Janovský, Zdeněk (advisor) ; Černá, Kristýna (referee)
Agricultural intensification is one of the main reasons for the decline of biodiversity and ecosystem services in agricultural landscape. One of the ecosystem services is pollination, which helps to preserve the biodiversity of wild plants in cultural landscape and is also vital for production of food, especially fruits and vegetables. Decreasing management intensity could be one of the potential solutions for maintaining sufficient level of pollination in the agricultural landscape. This can be achieved at least on parts of agricultural land. Also, certain areas of cultivated land can be excluded from production in exchange for subsidies for farmers who agree to implement this method. For this reason, the European Union has introduced organic farming and agri- environmental schemes. The aim of the study was to determine whether currently applied low-intensity management is sufficiently effective to protect wild plants, pollinators and their mutual relations. And if so, whether it is due to the decreased management intensity or due to the floral sources available. Another question dealt with is how the effects of organic farming depend on the landscape structure. Results of various studies dealing with this topic were qualitatively compared. Current studies show that organic farming has positive...
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Drivers of avian diversity on an altitudinal gradient of Mount Cameroon
Djomo Nana, Eric ; Hořák, David (advisor) ; Šálek, Miroslav (referee) ; Waltert, Matthias (referee)
Altitudinal gradients constitute a powerful test system for understanding distribution of species around the globe. Tropical mountains are quite rich in species even after controlling for environmental productivity, and are ideally suited for studying patterns of species distributions because they have had sufficient time for species to produce a response to environmental changes that affect their life histories. In this thesis, I investigate basic ecological mechanisms potentially behind avian distribution patterns along an altitudinal gradient in West-Central Africa. I used data collected with four methodological approaches (point counts, mist netting, random walks and artificial nest experiments) along an altitudinal gradient on Mt. Cameroon from October 2011 to September 2013. This work is focused on two interrelated themes: selection pressures on life histories (Chapters 1, 2, 3 & 4), and avian assemblage structures (Chapters 5 & 6). In the General Introduction, I present an overview of the study area with conservation implications of the study and my study objectives. In Chapters 1, 2 & 3, I investigate how selection pressures, i.e., nest predation and parasitism by haematozoa, affect bird assemblages. I used artificial nest experiments to assess nest predation rates in Chapters 1 & 2, and my...
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How do bird species richness and abundance differ between military training areas and surrounding landscape? A case study from the Hradiště military area
Bušek, Ondřej ; Reif, Jiří (advisor) ; Koleček, Jaroslav (referee)
Since the beginning of the 20th century human land use changed drastically in Central Europe. These changes included: homogenization of the landscape mosaic, intensification of agriculture, urbanization and land abandonment. In turn, these changes affected bird species and perhaps most significantly manifested in population decline of open habitat birds. Therefore, it is important to investigate sites, which were not affected by the changes mentioned above, such as military training areas (MTAs) - places dedicated to training of armed forces. Previous studies have shown that MTAs seem to host remarkably high bird diversity and abundant populations of bird species of conservation concern. This may be caused by two major factors. First, closure of MTAs to all human activies besides military training spared them of the landscape changes mentioned above. Second, the military training itself produces a very heterogeneous habitat mosaic that allows coexistence of many species with different ecological requirements. To my knowledge, no study compared bird assemblages between MTAs and surrounding landscape directly. At the same time, such data are crucial to assess the value of MTAs for bird conservation reliably and, as a consequence, they enable to think more deeply about mechanism generating this value....
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Forest vegetation changes in the Bohemian Forest during the second half of 20th century
Prach, Jindřich ; Kopecký, Martin (advisor) ; Sádlo, Jiří (referee)
Long-term forest vegetation changes were studied in the Bohemian Forest and its foothills. New vegetation relevés were taken at sites of typological plots established by forest engineers between 1955 and 1980. Data from 158 semi-permanent plots were analysed using modern statistical methods. The data show significant changes and homogenization of the vegetation. Ellenberg indicator values indicate eutrofication. Repeated measurements of soil pH suggest acidification, but the interpretation of these data is complicated by methodological problems. The forests under study exhibit high spatial variability. No main prevailing trend in vegetation changes was found. The changes are considered to be related to sulphur and nitrogen deposition and forest management. The influence of increasing age of forest stands seems to be unimportant. Discussed are not only vegetation changes and their possible causes but also the possibilities and limitations of using such old forestry data in botanical and ecological studies.
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More-individuals hypothesis
Bohdalková, Eliška ; Storch, David (advisor) ; Sedláček, Ondřej (referee)
Gradients in species richness are often explained by variation in energy availability. Positive relationship between energy and number of species may be caused by many mechanisms. One of them is the 'more individuals' hypothesis (MIH). According to it greater energy availability enable more individuals to coexist and more individuals can be divided into more species with viable populations. However, authors do vary in exact formulation of the MIH and so they vary in predictions that they test. Review of literature has also revealed that studies are fundamentally different in the approach to testing MIH. Some studies examine whether mechanism of MIH can operate in real assemblages and they often give a positive answer. Other studies ask whether MIH is able to explain spatial patterns of species richness. The answer is mostly negative. Number of species is often closely related to energy without the mediating effect of the number of individuals. There is also the question whether the number of individuals really determines number of species, and not vice versa. However, these two variables are certainly linked. Therefore, regardless of the causality, the relationship between the number of individuals and number of species is worth exploring.
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Military training areas as anthropogenic biodiversity refuges
Bušek, Ondřej ; Reif, Jiří (advisor) ; Marhoul, Pavel (referee)
Military training areas are used by armed forces as training territories. These areas are exposed to intensive anthropogenic disturbances. It may seem paradoxical that a number of studies had shown that on those particular areas is often present remarkably high biodiversity and numerous species of conservation concern. In this respect, military training areas are more valuable than most parts of surrounding landscape and thus form true biodiversity refuges. Particularly important are those areas for open habitats species. There are two main causes of uniqueness of military training areas. First, they are closed for any human activities not connected to military training. Because of this, these areas were not exposed to negative influences such as agricultural intensification or urbanization. Second, military activities create very heterogeneous habitat mosaic. This allows coexistence of many species with different ecological requirements. However, biota of military training areas is currently endangered due to abandonment by armed forces caused by downsizing national troops. The end of unique disturbance regime caused by military training leads to gradual homogenization of landscape mosaic and therefore to population decline of habitat specialists. Subsequent commercial development of these areas is another...
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Factors affecting dragonfly species composition in newly created pools and assessment of invertebrate predation on pools zooplankton
Dobiáš, Jakub ; Černý, Martin (advisor) ; Harabiš, Filip (referee)
To identify and quantify the influence of physico-chemical, biotic and geographic factors on the population of dragonflies (Odonata) is an essential tool for research of their ecology. The aim of this study was to 1) assess how these factors influence species richness, diversity and spatial distribution of dragonflies in 42 newly constructed or renewed pools located in the Kokořínsko Protected Landscape Area, which is characterized by two valleys of Liběchovka and Pšovka creeks, low human impact, and a great diversity of small water bodies and 2) use laboratory experiments in order to estimate the relationship between large predatory invertebrates of these pools (Aeshna cyanea, Coenagrion puella, Chaoborus crystallinus and Notonecta glauca) and their common prey (Daphnia curvirostris) in an artificial environment with or without aquatic macrophytes. The pools were monitored and sampled between years 2005 and 2006. In total, 23 dragonflies species were found inhabiting these lentic habitats, comprising 11 species belonging to the suborder Zygoptera and 12 species belonging to the suborder Anisoptera, including a rare species Sympetrum depressiusculum (larvae). Most variability in the dragonfly species richness was explained by the size of the water surface area, followed by the location of the pools (inside...
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On the Nothernmost and Southernmost Limits of European Land Snail Spatial Ranges
Křepelová, Lucie ; Juřičková, Lucie (advisor) ; Horsák, Michal (referee)
The aim of this work was to evaluate the limits of ranges of European land snail species along the north-south gradient. To work out the document it was necessary to prepare the set of digitalized maps, that enabled to create the database of ranges of the individual land snails species. Based on obtained data I tried to identify places where the northern and southern borders of species ranges are the most frequent. The landsnails' ranges are affected not only by particular life requirements of the individual species (potential limits), but also by other conditions, especially climatic, geographical and historical (truncated limits). In this work I focused on their differentiation. Above mentioned process also enabled me to track the north- south changes in species richness of the landsnails taking into consideration the truncated and potential limits. The most important natural barriers constraining that numerous of species cannot naturally widespread from the south to the north are the Scandinavian Mountains, the Alpes and the Carpathians and suprisingly also southern borders of german and polish lowlands. On the other hand, spreading of the species form the north to the south is limited only by the Alpes. I also tried to distinguish the group of species whose ranges are not influenced by these...
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Influence of understory light on diversity and composition of forest vegetation in the České Středohoří Mts.
Macek, Martin ; Kopecký, Martin (advisor) ; Černý, Tomáš (referee)
Light is essential component of forest ecosystem, as limited light availability in forest-floor restricts herb and tree seedlings growth. Importance of light availability for maintaining plant species diversity and community structure wasn't sufficiently evaluated in the Czech Republic. This study focus on the ecological relevance of light availability on both landscape and local scale. Relationship of light to cover, diversity and species composition was quantified in the thesis. Dominant tree species affected light availability and its spatial variability. Light availability was along the soil reaction and slope most influential factor for large-scale species diversity. Within-site light variability affected plant diversity more than soil reaction variability. Measuring light by means of hemispherical photography seems to be an appropriate for studies like this. Light availability influnence on community compostition is weak in comparison with other environmental gradients.
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