National Repository of Grey Literature 24 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
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.
Human-driven and natural vegetation changes of the last glacial and early Holocene
Kuneš, Petr
Conclusions The main conclusions, specific to each research topic, have been mentioned in appropriate chapter. To summarize, the thesis brings new original data and reinterprets existing pollen assemblages of the last glacial and early Holocene in central Europe. It also deals with analysis of the analogues and with vegetation-pollen relationship when interpreting past vegetation. The study of analogue environment brought several important conclusions. A considerably tight relationship was found between the composition of pollen spectra and climate characteristics in southern Siberian analogue landscape. This means that past climatic conditions can be reasonably predicted by the fossil pollen spectra. There were found the best pollen predictors (such as Pinus sylvestris, P.cembra, Betula alba, Artemisia, Graminae) and 300 m distance around the sampling point as the best factors explaining vegetation type. Vegetation was interpreted for the last glacial and the beginning of the Holocene in the light of new palaeobotanical finds and according to modern approaches. Occurrence of some tree species during various stages of the last glacial were confirmed, however, local discrepancies in vegetation and climate were also highly important. This supports strong gradient in increasing treelessvegetation from the...
Holocene fire history of forest vegetation in central Europe based on soil and sedimentary charcoal
Bobek, Přemysl ; Kuneš, Petr (advisor) ; Feurdean, Angelica (referee) ; Chytrý, Milan (referee)
Fire is a fundamental environmental factor that directly shapes many terrestrial ecosystems on Earth. The present thesis attempts to provide a comprehensive overview of the fire dynamics in Central Europe over the course of the last 12,000 years. Based on extensive analyses of charcoal particles deposited in terrestrial and lacustrine sedimentary sequences and carbonized plant tissues deposited in soils, I was able to track past fire dynamics across a range of spatial scales - from the forest stand scale to the landscape scale. First, we described relationships between drivers of recent fire occurrence and proposed linkages to the spatial pattern of Late-Holocene biomass burning. We found factors related to relief characteristics, such as increased thermal flux or terrain roughness, to be important determinants of fire occurrence within the present-day landscape. Contrary to all expectations, anthropogenic drivers seem to have a weak influence at present. Because relief-based factors have been stable throughout the Holocene, it seems probable that habitats of certain types are more predisposed to increased burning. We hypothesized that recurrent fire disturbances may contribute to the long-term maintenance of Pinus sylvestris-dominated forests, which withstood the competitive pressure of broadleaf...
Long-term disturbance dynamics of spruce forest in High Tatra Mts.
Beranová, Jana ; Kuneš, Petr (advisor) ; Jamrichová, Eva (referee)
Spruce forest is an important production ecosystem for our civilization. Its development can be affected by three main types of disturbances: forest fire, windstorms and spruce bark beetle attack. Experiences with a massive and long-term attack of spruce bark beetle in the Šumava mountains and a strong windstorm in 2004 in the spruce forest in the High Tatra provoke questions, how natural are such severe disturbances. To understand the current development of forest ecosystems, it is necessary to study past structure of these forests and frequency of forest disturbances. This work is about locality Tatranská Lomnice located in the High Tatra mountains, in the belt of mountain spruce forest. In my work, I used mainly pollen and plant macro-fossils analyses. I compared my data with disturbance information originating from dendroecology for windstorms and from charcoal analysis for fires. My research found that according to the pollen assemblages, most of the disturbances did not have strong influence on the forest composition, and most likely they only caused the forest thinning. The most significant fire occurred around 1420. The most significant wind disturbance probably occurred in 1890. The was not found any effect of spruce bark beetle. In the past millennium disturbances affected spruce forest...
Human-driven and natural vegetation changes of the last glacial and early Holocene
Kuneš, Petr
Conclusions The main conclusions, specific to each research topic, have been mentioned in appropriate chapter. To summarize, the thesis brings new original data and reinterprets existing pollen assemblages of the last glacial and early Holocene in central Europe. It also deals with analysis of the analogues and with vegetation-pollen relationship when interpreting past vegetation. The study of analogue environment brought several important conclusions. A considerably tight relationship was found between the composition of pollen spectra and climate characteristics in southern Siberian analogue landscape. This means that past climatic conditions can be reasonably predicted by the fossil pollen spectra. There were found the best pollen predictors (such as Pinus sylvestris, P.cembra, Betula alba, Artemisia, Graminae) and 300 m distance around the sampling point as the best factors explaining vegetation type. Vegetation was interpreted for the last glacial and the beginning of the Holocene in the light of new palaeobotanical finds and according to modern approaches. Occurrence of some tree species during various stages of the last glacial were confirmed, however, local discrepancies in vegetation and climate were also highly important. This supports strong gradient in increasing treelessvegetation from the...
Human-driven and natural vegetation changes of the last glacial and early Holocene
Kuneš, Petr ; Pokorný, Petr (advisor) ; Krahulec, František (referee) ; Ammann, Brigitta (referee)
Conclusions The main conclusions, specific to each research topic, have been mentioned in appropriate chapter. To summarize, the thesis brings new original data and reinterprets existing pollen assemblages of the last glacial and early Holocene in central Europe. It also deals with analysis of the analogues and with vegetation-pollen relationship when interpreting past vegetation. The study of analogue environment brought several important conclusions. A considerably tight relationship was found between the composition of pollen spectra and climate characteristics in southern Siberian analogue landscape. This means that past climatic conditions can be reasonably predicted by the fossil pollen spectra. There were found the best pollen predictors (such as Pinus sylvestris, P.cembra, Betula alba, Artemisia, Graminae) and 300 m distance around the sampling point as the best factors explaining vegetation type. Vegetation was interpreted for the last glacial and the beginning of the Holocene in the light of new palaeobotanical finds and according to modern approaches. Occurrence of some tree species during various stages of the last glacial were confirmed, however, local discrepancies in vegetation and climate were also highly important. This supports strong gradient in increasing treelessvegetation from the...
Long-term dynamics of Norway spruce (Picea abies) in relation to disturbances
Rayová, Světlana ; Kuneš, Petr (advisor) ; Abraham, Vojtěch (referee)
This thesis summarizes the basic knowledge about the dynamics of spruce forests in Europe on Holocene scale. It presents an overview of glacial refugia during the last glacial maximum and migration routes of spruce expansion to Europe. It also presents the basic facts about disturbancy dynamics and differences in disturbancy dynamics of northern and central Europe. In the last part, I have listed the basic palaeoecological methods that help in the study of spruce disturbances. Keywords: Norway spruce, Holocene, disturbance, dynamics, paleoecological methods
Changes in vegetation of Karpaty since glacial maximum - identificaition of main trends accesibility of data and gap in knowledge
Beranová, Jana ; Kuneš, Petr (advisor) ; Jamrichová, Eva (referee)
The Carpathian Mountains are great range in Europe. This rewiew is target to identify main evolution trends of vegetation i Carptahian Mountatins. I studied materials whitch was concetrate to pollen analysis and malacological finds. Based on this materials I found that in the stadial dryas periods there were climatic conditions for small forrest islands mainly formed from genus Pinus and Larix. In the interstadial periods the different climatic conditions permit forrest propagation and became denser. Transitions from pleistocen to holocen was nearly similar to the situation in interstadial period. But later in the holocene the density of the forest is growing more and dominant of late glacial forest was replaced mainly by the spurce. Population of plants that survive the glacial in the Carpathian mountain growing as same as and new species that survived glacial in warmer localities. In the subatlantic and especially in the few last decade the human efect is important and can be found in the pollen analysis. On the research of plant evolution in Carpathian mountain is necessary to continue, mainly on identification and analysis new localities. This large area is unequaly covered by localities.
Relationship between pollen diversity and floristic diversity - utilization for study of the past
Koďousková, Lucie ; Kuneš, Petr (advisor) ; Prach, Jindřich (referee)
This thesis deals with the relationship between palynological diversity and floristic diversity. Diversity is complex quantity, which consists of a number of species, the number of individuals and relative frequency of species known as evenness. It characterizes the diversity at the species level, genetic level or within communities. Its relationship with palynological diversity is problematic, especially because of lack of taxonomic precision in palynology, species-specific differences in pollen production and dispersal and sample size, since the number of taxa increases with sample size. The thesis also focuses on the studies which tried to prove positive correlation between palynological and floristic diversity, including techniques used. The second part describes methodology of collecting vegetational and palynological data and the treatment of sampes.

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