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Factors affecting reproductive success of deceptive orchids
Steffelová, Michaela ; Kindlmann, Pavel (advisor) ; Štípková, Zuzana (referee)
This thesis focuses on the study of the reproductive biology of nectarless orchids, which are characterized by the absence of nectar, resulting in pollinators not receiving a reward for pollen transfer. This factor can have a significant impact on the reproductive success of these plants. Furthermore, the reproductive success of nectarless orchids is influenced by other factors, such as inflorescence size, plant height, species, flowering time, population characteristics, or climatic and spatial conditions. This study examines nectarless orchids Anacamptis morio, Dactylorhiza majalis and Anacamptis pyramidalis as model species and measure the above-mentioned factors on the plants. The main findings of this study are: (i) The number of conspecific neighbors has almost no influence on reproductive success. (ii) There is a parabolic dependence between reproductive success and the number of flowers in the species A. morio and D. majalis, while in the species A. pyramidalis, this dependence is linear. The parabolic dependence of reproductive success on the number of flowers, predicted by the theoretical model presented here, was found in only one other study. The more frequently found linear dependence between these variables, found in this study only in the species A. pyramidalis, may be due to the...
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The importance of woodlots and their ecological characteristics for birds in an intensively managed agricultural landscape
Rajmonová, Lenka ; Reif, Jiří (advisor) ; Šálek, Martin (referee)
Various types of woody vegetation are a key biodiversity refugee in intensively managed agricultural landscapes. However, the role of woodlots, representing an important type of such a vegetation, remains overlooked so far. Whereas the previous studies focused on the effect of their area, shape and isolation, consequences of variation in their habitat quality for biodiversity were not assessed up to now. This thesis is thus one of the first studies focusing on woodlots as a specific habitat for birds in agricultural landscape. My goals were: (I) to find out what is the bird community composition of woodlots in a Czech landscape, (II) to find out, what are the key habitat predictors of bird species richness and abundance in woodlots, (III) to describe differences in habitat preferences among various guilds and (IV) to formulate recommendations for conservational practice. I surveyed birds in 82 woodlots in an intensively managed landscape in Central Bohemia, Czechia, and measured variables describing woodlots' habitat quality together with woodlots' area, shape, isolation and types of surrounding land-use. I recorded numerous forest and non-forest bird species (57 in total), including some endangered farmland birds. The habitat variables showing significant relationships to bird community...
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