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Autumn leaf senescence in temperate and boreal woody species under changing climate
Kosová, Barbora ; Lhotáková, Zuzana (advisor) ; Konrádová, Hana (referee)
Autumn senescence of the foliage of deciduous trees of temperate and boreal zones is an annually recurring phenological phenomenon, which is part of the adaptation to life in the temperate and boreal zones with periods of frost and restriction of solar radiation. During foliar senescence, photosynthetic pigments decompose, mineral nutrients are remobilized and foliage falls off. The timing of foliage senescence in boreal and temperate deciduous trees is controlled by external and internal factors. The biggest role in the timing of senescence is played by photoperiod and temperature, which gradually decrease by he end of the growing season. The temperature is increasing due to global warming, thus affecting the length of the growing season and the sequestration of carbon into forest stands. Other factors (such as water availability) are also affected by climate change. The above-mentioned factors affect the trees of boreal and temperate forests to varying degrees, and it is, therefore, important to address them in order to be able to estimate the future development of foliage senescence and carbon sequestration in temperate and boreal forests.
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Habitat selection in post-breeding temperate forest birds
THRIKKADEERI, Karthik
Habitat selection of forest birds in Branišovský les, České Budějovice, Czech Republic was studied by observing habitat preferences in the non-breeding season and exploring possible shifts in preferences due to the changing seasons. Patterns of habitat selection were analysed at multiple levels: considering all bird species as well as comparing between two feeding guilds. Preferences were also studied by specifically monitoring predation rates by birds on artificial caterpillars and exploring changes with habitat and season.
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Environmental drivers of microbial community composition in a temperate forest
Martinović, Tijana ; Baldrian, Petr (advisor) ; Vašutová, Martina (referee) ; Kopecký, Jan (referee)
Recently, much attention has been focused on the importance of forests to the global carbon cycle. Microorganisms are a critical component of the carbon cycle in forests, participating in important ecosystem processes and degrading various carbon compounds, from simple to highly recalcitrant compounds. However, most studies in this regard have focused on fungi. Only in recent years has it become known that bacteria are also capable of degrading complex plant polymers in soil, and that their contribution to the carbon cycle may be as important as that of fungi. Furthermore, our knowledge of the temporal dynamics of both fungal and bacterial communities is limited, as well as their response to different environmental drivers. The main objective of this dissertation was to fill these knowledge gaps by (1) quantifying the rate of temporal turnover of fungal and bacterial communities in soils of temperate forests, (2) describing the factors that shape fungal communities in spruce and beech stands during their long-term development (stand age), (3) assessing the contribution of fungi and bacteria to the utilisation of different carbon sources in forest soils, and finally (4) describing the development of bacterial communities in response to clearcutting of a spruce stand. The study of microbes...
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Effects of Climate change on root dynamics in temperate forests
Růžičková, Kateřina ; Bouda, Martin (advisor) ; Stiblíková, Pavlína (referee)
Fine roots contribute significantly to the global carbon and water cycle. Their dynamics and changes that may occur are therefore key players in these processes. Climate change significantly affects the dynamics of fine roots, and since individual factors are in interaction and may also function against each other, the overall response of the root system to climate change is difficult to predict. However, understanding these processes is essential for creating more accurate models to predict the response of ecosystems to a changing climate. This bachelor's project is a literature review that summarizes the knowledge about the effects of elevated temperature, CO2 concentration and drought on the dynamics of fine roots in temperate forests. Also, it provides a comprehensive view of the interaction of all three factors and considers some issues open for further research.
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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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