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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Volně žijící herbivoři jako vektor šíření druhů v opuštěné krajině / Free-ranging herbivores as a dispersal vector for species in abandoned landscape

Lepková, Barbora January 2014 (has links)
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...
2

Vliv pastvy koní na vegetaci / Horses and vegetation

Třeštíková, Tereza January 2011 (has links)
Many studies show that large herbivores can have an important impact on the composition of vegetation. With the establishment of a year round, low density grazing regime, plant ecologists and nature managers expect that through selective grazing, herbivores will create a mosaic of different vegetation communities varying in structure and plant species composition. It is believed that such a mosaic in the end will guarantee a high degree of biodiversity. Grazing will, therefore, seem to be a suitable means to maintain grass. Also important is the ability of herbivores affect vegetation through endozoochory. In this thesis I have tried to find out what species of diet horses prefer regarding to plant species and what plant species they can spread through out endozoochory. I have compared this knowledge with the composition of pasture and meadow vegetation at the researched locality in Malenice and Hoslovice. With the purpose of finding out the preferences I established spots where I registered data on vegetation before pasture and the time intervals during the pasture. Afterwards, I researched the amount of sprouts and the composition of seedlings in excrements that I let germinate. I had to create phytocenologic shots from the pastures and meadows to compare the species of composition of grazed and...

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