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Long-term disturbances in temperate mountain forests and their representation in various proxy data
Pavlišová, Adéla ; Kuneš, Petr (advisor) ; Moravcová, Alice (referee)
In this work, I present the main disturbance agents affecting temperate mountain forests in Central Europe - wind, bark beetles and fires, and I draw attention to their interdependence. I primarily deal with the description of disturbances, their consequences, ecological contribution, and climate influence on their action. With climatic warming, the extent, intensity, and frequency of disturbances increase. Hence, it is important to understand their role in the past to prepare for the future development of our forests. Proxy data (indirect data) provide past evidence for disturbances, but their interpretation value differs. They inform us about a different time and spatial scale with varying degrees of accuracy. All the methods that I mention in my work provide us, to some extent, with climate proxy data that is closely related to the disturbance regime. Only some directly prove the disturbance, for example, through sedimentary charcoals findings. My work aimed at indicating possible complications but also the advantages that arise when combining individual methods.
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Remnant of forest at the transition from Late Glacial period to Holocene: dendroecological and palaeobotanical reconstruction
Moravcová, Alice ; Šamonil, Pavel (advisor) ; Rybníček, Michal (referee)
The remains from a sub-fossil pine forest burried in layers of peat deposits at the northern edge of the CHKO Křivoklátsko in the Central Bohemia is completely unique findings for the area of the Czech Republic. It offers new opportunities for palaeoenvironmental reconstruction and related climate changes during the Late Glacial and early Holocene epoch. The methods of dendrochronology and radiocarbon dating were used to date subfossil trees. The results of radiocarbon dating determined the existence of the forest in the period approximately 12,000 to 10,300 cal yr BP. The dendrochronological analyses revealed two continuous floating chronologies. The chronology RD4, which is long 200 years, originates from the Younger Dryas. The chronology RD6, 300 years long, originates from the Preboreal. The growth dynamics of the forest were reconstructed on the basis of the tree- ring analysis. Hydrological regime has been identified as a major disturbancy factor that influenced the growth of trees. This has been evident from synchronous phase depressions in the growth of synchronized tree-ring series. The high water table was the main cause of their extinction. This was in concordance with the results of macrofossils analyses. The effect of hydrological regime was largely influenced by microsite differences...
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Natural forest disturbances palaeoecology
Moravcová, Alice ; Pokorný, Petr (advisor) ; Novák, Jan (referee)
This Bc. thesis deals with the disturbances, which form an integral part of many ecosystems. The main foci are natural disturbances (in contrast to anthropogenic ones) of temperate and boreal forests. I deal with the causes of major disturbancy factors (fires, storms, disease and insect pathogens) and their impact on the ecosystem. I focused in detail on fires, because they represent an essential factor in the development of many ecosystems. Moreover, they can be studied in the past by using several tools of palaeoecological analysis: dendroecology, anthracology and pollen analysis combined with micro-charcoal particles quantification. The last part of the thesis discusses the role of disturbances in the secular succession of Holocene vegetation in Central Europe. It contains a chapter that describes a research strategy focused to the study of natural disturbances through paleoecological methods in a specific location (Rynholec, Central Bohemia). Key words disturbances, vegetation dynamics, fire dynamics, secular succession, palaeoecological methods
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