National Repository of Grey Literature 53 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Population trends of African mammals
Homová, Viktória ; Storch, David (advisor) ; Hulva, Pavel (referee)
The African continent is known for its rich species diversity (biodiversity). We can read about the decline in African mammal populations in various sources. The main reasons of decline include loss of habitats and animal hunting. In spite of the general idea of decline mammals, in some cases the population trend is stable or growing. The aim of my thesis is to explore and summarize what is really known about the changes in the populations of all known mammalian species over the past decades. The attention of public is mainly oriented towards large flagship species, which are very well studied and various measures are put in place to protect them, especially in protected areas. The most marked decline in the number of individuals occurs in the western part of Africa, which is probably caused by a combination of lack of financial and human resources in animal protection, a large range of biotope damage and growing bushmeat trade. Species with increasing population trends are predominantly in South Africa, where there is an improvement in the management and the protection of wildlife receives more attention. Considering small mammals, there is, in most cases, no relevant data available to help determine their population trend. The population trends of species residing in the tropical rainforests are...
Hydroacoustic assessment of the fish stock in Lake Balaton in 2017
Tušer, Michal ; Muška, Milan
This report describes a study of open-water fish assemblage in Lake Balaton, Hungary, in 2017. The lake was acoustically surveyed using two horizontally-oriented 120 kHz transducers. The observed fish stock was assessed on the basis of fish sizes, abundance, biomass, and spatial distribution in the lake.
Ecological traits as a correlates of spatial variation in abundances of a Czech birds
Farkač, Jan ; Hořák, David (advisor) ; Reif, Jiří (referee)
Jan Farkač, Diplomová práce 2018 Abstract Bird species differ in their local densities, which seems to be related to their geographical distribution and species-specific traits. Investigating such a relationship can help us to understand better how the birds inhabit the space. The aims are as follow (i) to take an alternative approach to densities by counting them just in species preferred habitats and (ii) to explain the abundance characteristics such as an absolute density, variation in local densities or occupancy by species-specific traits. The relationship between abundance characteristics (local densities and their coefficient of variation in space) and avian traits such as a habitat specialisation, diet specialisation, PCA of morphological traits, PCA of reproduction traits - as an estimate of slow-fast continuum and a range size were tested using GLM. There are two abundance characteristics significantly related to species specialisation index. I have used the data from the Common Bird Monitoring Program run in the Czech Republic by the Czech Society of Ornithology. Due to the highest amount of records I have selected data from the year 2009 and subsequently species occupying more than 50 transects (out of 129), which resulted in inclusion of 47 species into analyses. This thesis contains...
Dominance of different groups of animals in terrestrial ecosystems
Matysová, Barbora ; Storch, David (advisor) ; Tropek, Robert (referee)
There are some beliefs about the abundance and biomass of different animal groups, which persist in general awareness. At the same time, the ideas of the general public relate to the influence and importance of the animals for an ecosystem. The aim of this paper is to make sure that these assumed concepts of dominating entities are based on truth or if they are only mistaken rumors, and to answer the following questions: whether the biomass of large herbivores or termites is significant in the tropics, what is their influence on decomposition of vegetation matter; if the biomass of all ants actually exceeds the biomass of all people in the world; whether the abundance of prey and predators is stable across ecosystems; if there are more herbivores in tropical or cold ecosystems; or when predominant abundance of ants or termites is present in tropical ecosystems. Responses are gained through the extensive collection of abundance and animal biomass data from expert articles and publications. In order to be verifiable as well as the stability of the given ratios over the years,there were used data from the oldest traceable materials about 80 years old to the current data from current works. In addition to biomass and abundance values, attention is also paid to the methods used by scientists to collate...
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
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....
Vliv vypouštění oteplených vod na makrozoobentos malého toku
Voltemar, Erik
Bachelor thesis is focused on the theme: Effects of discharge of heated water to macrozoobentos of small stream. The aim of this thesis was to develop literature search on the impact of thermal pollution on aquatic ecosystems and temperature tolerance of aquatic invertebrates. For purposes of practical studies were selected four streams in the vicinity of nuclear power plant Dukovany. For complex results were streams observed during the autumn 2013 and spring 2014. At affected Skryjský stream were selected four sampling sites SP0-SP3 for objective monitoring. Locations LIP, HER and LUHY, were not directly affected by the warmed wastewater from nuclear powerplant and serve as comparison sites. At all locations were conducted multi habitat samplings by method PERLA. At the same time they were measured basic physical and chemical parameters and collected samples for determination of basic chemical parameters. From results was determined abundance, taxonomic composition, diversity and functional structure of water macroinvertebrates. At the same time were also evaluated differences in the composition of communities in influenced and reference streams. Results shows that the heated water from the nuclear powerplant have a significant impact on reducing makrozoobentos at Skryjský stream. Due to high temperature and conductivity of waste waters in autum 2013 and spring 2014 were abundance and taxonomic composition at Skryjský stream significantly reduced. At locations LUHY, LIP and HER were not identified adverse effects of the discharge of heated water from nuclear powerplant.
Diverzita plevelů v podmínkách odlišného střídání plodin
Daníčková, Lucie
The aim of this study was to evaluate the species composition of weeds in the crop. Spring barely has been grown in the monoculture and also within the Norfolk crop rotation. The ground was utilized in two ways. The first way was classical (traditional) technology with using of deep plowing, the second way was minimization of technologies. Observation of the field trial was done in 2014 and 2015 and the results of this experiment were evaluated in the period between 5.5.2014 and 2.5.2015 prior to application of herbicides. Numerical method has been used there, the number of weeds was detected per 1 m2 for each variant tillage and crop rotation in 25 repetitions. Results of the evaluation of weed crops of spring barley were first processed by using DCA analysis. The result is a length of the gradient (Lengths of gradient). In our case it was 5.058. For further processing was chosen canonical correspondence analysis CCA. Analysis CCA defines the spatial arrangement of individual weed species and studied factors of cultivation practices (crop rotation, tillage) based on data about the frequency of occurrence of weed species. This is later graphically expressed by the ordination diagram. At the study area were recorded overall 31 weed species. The greatest abundance was found on land, where minimizing tillage technology was used. Diversity in traditional tillage was comparable with diversity in the minimization tillage and it was therefore impossible to establish whether the tillage effects on species diversity of weeds. In monoculture we found 13 weed species all together, while on the ground were we use Norfolk crop rotation, there were a total of 17 species. It is therefore possible to conclude that the practical use of crop rotation has a positive impact on the diversity of weeds. Crop rotation was probably more suitable for those species: Arctium tomentosum, Capsella bursa-pastoris, Cirsium arvense, Convolvulus arvensis, Erodium cicutarium, Euphorbia helioscopia, Chenopodium album, Chenoodium ficifolium, Chenopodium hybridum, Chenopodium quinoa, Malva Neglecta, Polygonum aviculare, Sonchus oleraceus, Thlapsi arvense, Trifolium alexandrinum, Tripleurospermum inodorum and Viola arvensis. I recommend to continue the field trial in order to evaluate the long-term ties weeds on crop rotations and tillage.
Abundance of and threats to the snow leopard in various regions of its occurrence
Valentová, Kamila ; Kindlmann, Pavel (advisor) ; Hulva, Pavel (referee)
Snow leopard (Panthera uncia) is an endangered species and its population size is steadily declining. This thesis attempts to introduce and analyse the main factors threating its survival with reference to each country of its occurrence: China, Bhutan, Nepal, Pakistan, Afghanistan, Tajikistan, Uzbekistan, Kyrgyzstan, Kazakhstan, Russia and Mongolia. To conserve the remaining snow leopard populations, it is necessary to detect its distribution in various areas. Here, recent data about its worldwide distribution are presented. Snow leopard has a very secretive lifestyle, which makes estimation of its abundance quite difficult. Therefore, I also present here an overview of methods, such as sign survey, capture-recapture, predator:prey biomass ratios, photo-capture rate and genetic analyses, used for estimation of abundance of snow leopard with reference to conducted studies. I discuss their advantages and disadvantages under different conditions. Key words: snow leopard, abundance, threats, worldwide distribution, conservation
Feral Pigeon (Columba livia f. domestica) Census in Selected Sites of Prague
Bukačová, Kateřina ; Řezníček, Jan (advisor) ; Štěpán, Jiří (referee)
This thesis deals with the monitoring of numerous rate of domestic pigeon (Columba livia f. Domestica, hereinafter referred to as pigeon) in a given area and its spatial activity. The work includes incidence monitoring of individual pigeons depending on daytime and weather. The monitoring was carried out by observational method in the period from February to May 2015. The observations were related to individuals who occurred the monitored area (the buildings in Dukelských hrdinů street). Furthermore, the work compares the results from population census of Prague pigeon and the results from census of other European cities. It was further investigated whether the amount of pigeons in the area is affected by abiotic conditions (air temperature and weather). The result of the thesis should contribute to better knowledge of overall pigeon rate determining in the capital city of Prague. The collected data may help to gain a deeper knowledge of the entire population ecology living in this territory. They can also be beneficial, for example, in reducing of the pigeon numbers or serve in other investigations. Key words: pigeon, Domestic Pigeons (Columba livia f. domestica), abundance, monitoring, abiotic conditions, population

National Repository of Grey Literature : 53 records found   1 - 10nextend  jump to record:
Interested in being notified about new results for this query?
Subscribe to the RSS feed.