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Towards the understanding of agricultural intensification impacts on farmland birds: the effects of changes in invertebrate food supply
Hološková, Adriana ; Reif, Jiří (advisor) ; Lučan, Radek (referee)
Populations of insectivorous farmland birds recently underwent dramatic declines. Agricultural intensification is the main cause of these population changes, but involves numerous different mechanisms. Changes in food supply are thought to be one of the key factors. Homogenization of diet supplied to insectivorous chicks reduces their growth rate resulting in their smaller size as adults; decreased abundance of prey affects both survival and fitness of chicks and the overall breeding success. The accessibility of food is one of the most important factors limiting the use of food-rich habitats. However, the impact of all these factors on population trends has been shown in a single species - grey partridge. While the effect of changes in food supply on the breeding success has been confirmed in many other species, there is a lack of information on subsequent links to the survival of fledglings and the major causes of mortality outside the breeding period remain unclear. In general, there is insufficient information on population consequences of the changes in food supply for farmland birds, particularly in Central and Eastern Europe - the region with different characteristics from those we find in regions in which most of the findings were collected. Without this information, it is difficult to...
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Winter irruptions of birds in Europe
Souček, Michal ; Lučan, Radek (advisor) ; Hořák, David (referee)
Besides regular migrations, a phenomenon called "eruption", "invasion" or "irruption" exists in bird migratory behaviour. Although this phenomenon has been known since 19th century, its basic mechanisms are still not clear or are subjects of discussion. This bachelor thesis summarises in a form of review up-to-date knowledge and theories about winter irruption with information about all winter irruption occurrences in Czech Republic. Key words: Aves, irruption, winter invasion, migration
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Distribution and habitat preference of the Ortolan Bunting in the Czech Republic
Zeman, Vít ; Lučan, Radek (advisor) ; Šťastný, Karel (referee)
The Ortolan Bunting (Emberiza hortulana) is a farmland bird species, whose population size has declined very sharply in recent decades, especia ll y in Western and Central European countries. The aim of our study in 2015 was to record where the last populations of this critically endangered species in the Czech Republic are located and also what habitat the species associated with. We examined nine areas (925 km2 in total). Two main areas of occurrence (surface mines in northern Bohemia and farmland landscape of Silesia) and two small isolated populations in central Bohemia were registered for this species. In contrast, observations in some traditional areas of its occurence (České středohoří in northern Bohemia, Hovorany-Čejkovice region in southe r n Moravia and Javoricko region in Silesia) were negative. Altogether, we counted 75-79 singing males. Our estimation of the size of the Czech population in 2015 is 75-100 singing males, which indicates further population decline compared to the last mapping in 2001-2003. Furthermore, habitat associat io ns were investigated at two spatial scales and we made habitat compar is o n between farmland and post-mining landscape. Our research highlights a high degree of flexibility in habitat selection of Ortolan Bunting and also positive association with high...
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Selected aspects of autumn migration of birds and bats over a mountain pass
Koukolíková, Anna ; Lučan, Radek (advisor) ; Cepák, Jaroslav (referee)
Mountain passes situated in mountains of east-western orientation serve as important bird and bat migration corridors. Due to the increased concentration of migranting individuals in both groups, mountain passes can be used to study various aspects of migratory ecology. Within the Czech Republic, the most important site of this type is Červenohorské sedlo in Jeseníky. In this thesis, selected aspects of autumn migration (composition of the migratory population, phenology, factors influencing its intensity) of birds and bats during the autumn season were compared. In addition, data usability was compared for a reliable determination of autumn phenology in selected model bird species based. The comparison was between standardized mist netting in the mountains and set of data obtained from faunistic observations throughout the Czech Republic. Data from mountain mist netting has proven to be a more reliable indicator of the timing of bird migration, mainly because most species fly directly and quickly over the mountains, while in low-level observations there is a risk of mixinglocal and migratory populations. Also the number of observed individuals in some cases reflects the interest in extreme late occurrences in many species, which are generally given more attention and are more frequently recorded...
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Size and stability of territories in tropical birds
Charvátová, Barbora ; Hořák, David (advisor) ; Lučan, Radek (referee)
The size and the stability of avian territories are at first sight quite different in the tropics if compared to the temperate zone. Territories of tropical birds are relatively more stable in time and space. Their owners defend territories year-round, between years and the boundaries of territories remain unchanged. Tropical territories are also many times larger in size. These specific properties are conditioned by many interconnected factors. The size of the owner and food availability have a significant influence. The size of the territory increases with the size of the owner. And the owner reduces territory size with a higher food supply. It is food availability, which is closely related to the quality of the environment. Generally, the density of individuals is lower in lower quality areas. Thus, owners adapt their territories - increase size. This is especially interesting in the tropics, considering that there is much higher species richness and lower population density than in the temperate area. Differences in territory can also occur due to different altitudes - there are larger territories in tropical montane cloud forest. Also, the location in the area and potential barriers have influence, but rather in position than in a size. Studying these factors explains the differences in...
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Which effects govern intensity and timing of bird migration?
Koukolíková, Anna ; Lučan, Radek (advisor) ; Peške, Lubomír (referee)
Avian migration is one of the most striking manifestations of environmental seasonality in areas with higher latitude and is therefore not surprising that the study of this phenomenon has attracted biologists since immemorial times. One of the interesting findings is the fact that the spring and autumn migration does not take place at all times with the same intensity, but in most species noticeable migration maxima (waves)can be observed, often present over large geographical areas. Such synchronicity in migration behaviour implies the existence of specific triggers that affect migratory species populations. The presented thesis summarizes the current state of knowledge of factors (e.g. climatic, lunar, solar etc.) affecting the timing and intensity of bird migration. Key words: migration ecology, Aves, climate
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Geographic variability in the size of maternity colonies of cave bats
Oppelová, Tereza ; Lučan, Radek (advisor) ; Andreas, Michal (referee)
Main goal of this thesis was to compare geographical variability of sizes of colonies in the relationship with the type of roost of 6 models of originally cave bats species: Greater mouse-eared bat (Myotis myotis), Geoffroy's bat (Myotis emarginatus), Common bent-wing bat (Miniopterus schreibersii), Greater horseshoe bat (Rhinolophus ferrumequinum), Lesser horseshoe bat (Rhinolophus hipposideros) a Mediterranean horseshoe bat (Rhinolophus euryale). The selected data set was also analyzed the possible influence of the composition of land cover in roosts around the variability of the size of the colonies. Based on compilation of literature and active communication with regional bat-monitoring coordinators, entries about size of colonies from 2 603 locations in 24 countries of Europe were collected. 1 952 entries were from roosts in buildings and 651 from caves. Based on statistical analysis, conclusive influence of type of roost on size of colonies by M. schreibersii, M. myotis a R. hipposideros was discovered. While in M. schreibersii and M. myotis are human colonies in smaller buildings, in R. hipposideros by contrast, they are larger. Simultaneously, north-west gradient in geographical distribution of maternal bat- colonies in dependence on type of roost (caves vs. buildings): in southern areas...
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Effect of habitat fragmentation on bat ecology
Kočí, Jakub ; Lučan, Radek (advisor) ; Hořák, David (referee)
Habitat fragmentation poses one of main threats to biodiversity. Bats (Chiroptera) serve as an important group of bioindicators. Habitat disturbance can induce different answers among them, especially in a tropical forest where bats provide important ecosystem functions such as seed dispersal and plant pollination. Difference between their reactions can be seen between different biomes: Negative influence to the species richness can be expected in a tropical forest with high degree of endemism whereas in temperate zone with long-term human influence to the landscape composition bats might have partially adapted to patchiness of the landscape and fragmentation could have locally positive effect. This thesis aims to summarize current knowledge of how fragmentation influences bat ecology with special aim for the difference between various biomes. Key words: Bats, Chiroptera, fragmentation, neotropics, paleotropics, Europe, temperate zone
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Scaling of spatial activity in bats
Křemenová, Jana ; Lučan, Radek (advisor) ; Storch, David (referee)
2 ABSTRACT The degree of spatial activity, especially the home-range size, is one of the basic biolog- ical characteristics of animals and whether it has enough resources is crucial for the survival and reproduction of the individual. Therefore, it is not surprising that many studies trying to make clear the effect of various ecological and morphological variables and explain the varia- bility of space activities. Bats are a group of mammals, for which until recently, existed only few information about their spatial activity. However, due to the miniaturization of technology and the use of radiotelemetry amount of information rapidly increasing. The aim of this study was to assemble the most complete information about the home- range size and foraging distance of bats and analyze the effect of variables that can influence the spatial activity. From published papers I collected data on 106 species representing 8 fami- lies. The influence of 6 variables (weight, wing loading, aspect ratio, food specialization, colony size, primary productivity of environment) on home-range size and average foraging distance of bat was analysed by phylogenetic regression (PGLS). The best predictor of the home-range size is the primary productivity of the environment, food specialization and body size. The best explanation of...
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Invasive alien mammal species in Europe
Hadravová, Alena ; Reif, Jiří (advisor) ; Lučan, Radek (referee)
The present thesis deals with the invasive species of mammals in Europe. Invasive mammals have far- reaching impacts both on the environment and on the economy. It is necessary to avoid the transfer and dissemination of such invasive species in the new environment. To prevent the spread of these species and to control them in general, it is crucial to know their characteristics and to strike at an initial phase of the invasion. The characteristics which make invasive species particularly successful in the new environment are, i.e., wide ecological valence, the ability to disseminate quickly, high competitive potential, and the potential to reproduce in the new environment. Another important factor which contributes to sustained existence of invasive species in the new environment is the absence of predators, parasites, and pathogens. Among the management practices which proved to be effective are shooting, trapping, and baiting, fencing and tree protectors are effective, too. In general, the management should be directed towards long-term reduction of population size to a predefined level based on mitigation of impacts and reduction of management costs. The EU Strategy on Invasive Species involves a three-stage approach, the three stages being prevention, eradication, and containment. All European states...
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