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The role of soil macrofauna in organic matter decomposition and stabilisation
Špaldoňová, Alexandra ; Frouz, Jan (advisor) ; Tajovský, Karel (referee) ; Smrž, Jaroslav (referee)
Slowdown of plant litter decomposition is one of the many ways how to increase the amount of organic matter in soil and thus contribute to both the restoration of organic matter in soil and reduction of the amount of carbon dioxide in the atmosphere. Here we focused on the long-term effect of soil macrofauna on organic matter decomposition and stabilization. In two long-term microcosm experiments, common isopod (Armadillidium vulgare) greatly affected both leaf litter decomposition and organic matter chemistry. Microbial decomposition was lower in excrements than in litter or unconsumed leaf fragments. At the same time, moisture and temperature fluctuations and addition of nutrients increased decomposition much more in litter than in the excrements. Chemical analyses revealed preferential loss of polysaccharide carbon and accumulation of lignin with some modification to aromatic carbon in excrements when compared to litter; the two substrates also differed in lignin quality. Additionally, we observed that phenolics content in leaf litter is considerably affected by both microbial and isopod feeding activities. In the third long-term microcosms experiment, we compared consequence of bioturbation of the epigeic earthworm (Lumbricus rubellus) and mechanical mixing of organic matter into soil on carbon...
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Trade-off between egg size and number at the level of bird families
Špaldoňová, Alexandra ; Hořák, David (advisor) ; Reif, Jiří (referee)
Trade-off between offspring size and number belongs to the most discussed concepts in the life history theory. The aim of this study was to elucidate the relationship between egg size, clutch size and female body mass at the family level in bird's and to examine whether there is the relationship between offspring size and number and life history traits specific for particular bird families. From published sources, I collected data about 5.073 species belong in 146 families. Most species of birds lay smaller clutches, on average three eggs. In 112 families from 130 tested eggs size was positively correlated with female body mass. There is evidence that egg size and clutch size are inversely related in 83 families from 130 tested but only for 34 families was significant. The relationship exists independently of female body mass across bird families and this suggests a trade-off between these traits. The relationship between the strength and shape of egg size-number correlations and life history characteristics of bird families was not frequent. According to results, the strength of correlation seems to be related to development mode and diet type. The negative egg size-number correlation is stronger when incubation period and fledging time is longer and in birds with longer lifespan. The...
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