|
|
Factors affecting the occurrence of rare protist species
Herciková, Zuzana ; Škaloud, Pavel (advisor) ; Jadrná, Iva (referee)
This bachelor thesis aims to answer the question that even Darwin asked, and which is still relevant today: which factors influence the occurrence of rare species? In the first part of this thesis, this question is applied in general to species of all organisms. First, the term rare species is defined and other general information on the distribution, proportion of rare species in ecosystem and importance of rare species are mentioned. Then biotic and abiotic factors, that influence the occurrence and existence of rare species of all organisms are mentioned. These include, for example, the size of the organism, abiotic environmental conditions, in which the organism is found, etc. The second part of this thesis is focused on the rarity of protists. First, it is discussed whether rare protists actually exist. Due to their small size, large populations, short generation time and easy dispersal, they are often considered ubiquitous. Factors that could influence the occurrence of protists are discussed next. These factors are for exapmple habitat size, dispersal ability and changes in the environment in which they occur. It is not possible to clearly say why some protists are rare, or even to categorize in general terms what factors are key to the occurrence of rare protists. Key words: rare species,...
|
|
| |
|
|
Germination requirements of rare and common plant species of Giant Mountains
Paulů, Andrea ; Münzbergová, Zuzana (advisor) ; Moravcová, Lenka (referee)
For a long time studies were focused on searching optimal conditions of germination of individual species. During the last few years studies have started to search for a relationship between germination and various species characteristics. Most of them, however, use only one temperature during germination tests. Very few studies use more than one temperature during the germination tests. In the last years studies started also to compare germination between rare and common species, but these studies compare just a few species. There are no studies which would compare germination on broader range of species. Aim of this study was to indentify which factors are determing germination of species and to find relationships between germination and characteristics of rare species (n=62). Another aim was to find out differences in germination of pairs (n=24) of closely related rare and common species. To test the germination I have chosen a methodology with several consecutive temperatures. Throughout the time of testing , the seeds were placed either in light or in dark. The dataset was processed by linear regression. The results show that germination requirements of species are determinet by time of flowering, weight of seeds, dispersal mode, species requirements for soil humidity and nutrients and type of...
|
|
|
Predictive distribution modelling of selected bryophyte species in Bohemian Switzerland National Park
Procházková, Martina ; Man, Matěj (advisor) ; Moudrý, Vítězslav (referee)
The aim of this thesis was to create potential distribution models for Dicranum majus (Greater Fork Moss) and Polytrichum alpinum (Alpine Haircap) in Bohemian Switzerland National Park. In the Czech Republic these bryophyte species occur in cold climatic regions typically with higher altitudes. In Bohemian and Saxon Switzerland they can occur in really low altitudes thanks to unique microclimatic conditions of deep inversion ravines. These bryophyte species had low number of occurence records in studied area before the start of my research (4 occurence localities for Dicranum majus, 8 occurence localities for Polytrichum alpinum). Predictive habitat suitability models can be an effective tool for selecting potential new occurence localities, planning field research or management design. During field research I recorded 34 new occurence localities for Dicranum majus and 29 new occurence localities for Polytrichum alpinum in Bohemian Switzerland National Park. I used 8 topographic parameters derived from digital elevation model with 1 m resolution as environmental data. Using these data I created models of potential distribution of the most suitable habitats for both species with algorithms Artificial neural networks (ANN), Generalised linear model (GLM) and Random forest (RF). RF algorithm had the...
|
|
|
Can the capercaillie (Tetrao urogallus) reintroduction be successful?
Stelšovská, Lenka ; Křenová, Zdeňka (advisor) ; Reif, Jiří (referee)
The western capercaillie (Tetrao urogallus) used to be a common species in Europe but, during the last decades, the species declined rapidly in the western part of its range, i.e. in Central and Western Europe. Decreasing of the habitat quality, inappropriate forest management, climate changes, disturbing by humans (sport & tourisms) together with very only low adaptabity of this species were recognized to be the most important factors threatening Tetrao urogallus. Also predation is a very important stress factor. Numbers of reintroduction projects have been conducted in Europe to improve the situation. This study summarizes current knowledge about reintroduction projects and their effectivity. Most of the projects were not successful very much. Reintroduction projects were implemented also in the Czech Republic in 1998 - 2007 and capercaillies have been released in several regions (Šumava, Český les, Krkonoše, Jeseníky, Moravskoslezské Beskydy, and Brdy). No new populations were established. The reasons for the failure have been found in the insufficient quality of the biotopes, predation, the physiological and ethological deficiencies of the young birds and the ways of their rearing. It is possible to summarize, that the reintroduction projects seem to be low effective but they are not completely...
|
|
|
Germination requirements of rare and common plant species of Giant Mountains
Paulů, Andrea ; Münzbergová, Zuzana (advisor) ; Moravcová, Lenka (referee)
For a long time studies were focused on searching optimal conditions of germination of individual species. During the last few years studies have started to search for a relationship between germination and various species characteristics. Most of them, however, use only one temperature during germination tests. Very few studies use more than one temperature during the germination tests. In the last years studies started also to compare germination between rare and common species, but these studies compare just a few species. There are no studies which would compare germination on broader range of species. Aim of this study was to indentify which factors are determing germination of species and to find relationships between germination and characteristics of rare species (n=62). Another aim was to find out differences in germination of pairs (n=24) of closely related rare and common species. To test the germination I have chosen a methodology with several consecutive temperatures. Throughout the time of testing , the seeds were placed either in light or in dark. The dataset was processed by linear regression. The results show that germination requirements of species are determinet by time of flowering, weight of seeds, dispersal mode, species requirements for soil humidity and nutrients and type of...
|
|
|
Ecology and genetic diversity of Gentiana pannonica populations in different geographical and habitat scales
EKRTOVÁ, Ester
The thesis focused to population ecology and genetics of subalpine species Gentiana pannonica. Pollination ecology of species and generative reproduction in different habitat (primary vs. secondary) were investigated in the field. Genetic variation and structure of G. pannonica populations were studied in three disjunct parts of its distribution range: the Eastern Alps, the Bohemian Forest, and the Giant Mts. Present distribution of G. pannonica in the central past of the Bohemian Forest were processed.
|
guest ::
