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Aboveground litterfall fluxes of selected elements in central European temperate forest
Bašta, Jan ; Oulehle, Filip (advisor) ; Chuman, Tomáš (referee)
5 Abstract Aboveground litterfall is the most important intrasystem flow in the temperate forest ecosystem. It is also the largest input flux to the soil surface for most of the macronutrients (N, P, Ca, Mg, K). However, under Central European conditions, studies on the magnitude of this flux in relation to elemental stocks are lacking. GEOMON Small Forest Catchment Network is used to investigate long-term trends in nutrient cycles in temperate forests of Central Europe and the human influence on them. As part of this network aboveground litterfall collectors were placed in 14 catchments at a total of 19 sites at the end of 2019. Litterfall was then collected bimonthly, weighed and sorted into different fractions. These fractions were analyzed to determine the concentration of the elements of interest. From these values, the fluxes of the elements in the aboveground litterfall were calculated. The observed values were compared with the characteristics of the individual sites and the element budgets in the catchments. The monitored elements can be ranked according to the size of the flux of the element through the aboveground litterfall in relation to other inputs of that element to the soil as follows: C, P, N, Ca, Mg and K. The average amount of aboveground litterfall in the GEOMON network is 4.6...
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Pollination in forest ecosystems
Veljačiková, Hana ; Janovský, Zdeněk (advisor) ; Hadrava, Jiří (referee)
Interactions between plants and their pollinators in temperate forest are different from open habitats. In forest, pollinators are less abundant and this results in frequent pollen limitation of forest understory herbs. Pollinators also need to be adapted for flying in complex stands and for living in unfavorable microclimatic conditions. Floral resources predominantly limit pollinator abundance because of their uneven distribution in space and time. In the present bachelor thesis, I summarize knowledge on pollinator conservation and phenology as well as food resources, microclimate, which together with sufficient nesting options seem to contribute the most to pollinator abundance. Type of forest management is also an important factor, which affects density and diversity of pollinators. Generally, thinning out of trees and removal of understory shrubs have positive effect on flower abundance and benefit pollinators. Factors that influence reproduction success of flowers and pollen transfer distances are further discussed.
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Wood ants of genus Formica as important ecosystem engeneers
Jílková, Veronika ; Frouz, Jan (advisor) ; Tajovský, Karel (referee) ; Bonkowski, Michael (referee)
This thesis consists of one chapter accepted for publication in a book and four papers published in international journals with impact factors. All of the contributions deal with the role of wood ants in energy and nutrient fluxes in forest ecosystems. Wood ant nests are known as hot spots of carbon dioxide (CO2) production and are also thought to affect methane (CH4) flux. Stable high temperatures are maintained in ant nests even in cold environments. This study is focused on quantification of CO2 and CH4 flux in wood ant nests, contribution of ants and microbes to CO2 production, properties of nest material that affect CO2 production and the role of ants and microbes in the maintenance of nest temperature. The research was conducted in temperate and boreal forests inhabited by wood ants (Formica s. str.). Gas fluxes were measured either by an infrared gas analyser or a static chamber technique. Ants and nest materials were also incubated in a laboratory. Material properties potentially influencing CO2 flux, such as moisture, nutrient content or temperature were determined. According to the results, CH4 oxidation was lower in wood ant nests than in the surrounding forest soil suggesting that some characteristics of ant nests hinder CH4 oxidation or promote CH4 production. Wood ant nests clearly are hot...
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Vegetation changes in Czech lowland forests over the past decades
Kopecký, Martin ; Hédl, Radim (advisor) ; Chytrý, Milan (referee) ; Diekmann, Martin (referee)
Vegetation changes in Czech lowland forests over the past decades Martin Kopecký ABSTRACT To explore decadal changes in plant species diversity and composition of typical lowland forests in the Czech Republic, I compared vegetation on plots sampled decades ago with vegetation on the same plots sampled recently. First I evaluated the robustness of the approach used in my thesis. In Chapter 1, we provided the first direct test of the effect of uncertainty in original plot location on results from vegetation resurvey. We found that temporal trends in vegetation diversity and composition were comparable between exactly relocated permanent and only approximately relocated semi-permanent plots. Therefore, we conclude that the resurvey of semi-permanent plots is robust to the uncertainty in original plot location. Then, we showed that vegetation in lowland oak forest shifted from species-rich communities of thermophilous forest toward species poorer communities of mesic forest (Chapter 2). The species typical for thermophilous oak forests and nationally endangered species suffered the most significant decline. We identified as the main driver behind these changes shift from traditional coppicing toward high forest management after WWII. Further, we explored the processes behind temporal shifts in species diversity...
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