|
|
Imprints of history in post-agricultural forests
Vojta, Jaroslav ; Suchara, Ivan (advisor) ; Honnay, Olivier (referee) ; Tichý, Lubomír (referee)
IMPRINTS OF HISTORY IN POST-AGRICULTURAL FORESTS Ph.D. Thesis Jaroslav Vojta Charles University in Prague, Faculty of Science Praha, 2010 Promotor: Ivan Suchara List of original papers I. Relative importance of historical and natural factors influencing vegetation of secondary forests in abandoned villages (Jaroslav Vojta - Preslia 79: 223-244) II. Land use legacies in post-agricultural forests in the Doupovské Mountains, Czech Republic (Martin Kopecký & Jaroslav Vojta - Applied Vegetation Science 12: 251-260) III. Woody vegetation continuity, topography, and distance to ancient forests have complex effects on the vegetation and species richness of abandoned pastures (Lucie Drhovská & Jaroslav Vojta - submitted) 1 Introduction Land use changes have had a profound effect on vegetation cover. Often, succession results in the recovery of forests on former agricultural land. As areas of post-agricultural forests become increasingly prominent in landscapes of developed countries, these processes have attracted the attention of ecologists. Many questions have arisen regarding the possibility of restoring original forest communities on former agricultural lands (Flinn and Vellend, 2005; Hermy and Verheyen, 2007). At the same time, current and past land use changes could be seen as "natural experiments" that could...
|
|
|
Vegetation changes of urban forests
Kučerová, Tereza ; Hédl, Radim (referee) ; Vojta, Jaroslav (advisor)
Urbanization is one of the most intense and biggest factor of homogenization created by human. Cities produce environment which is important just for one species and it is homo sapiens. Very important is also instability of pumping natural resources instead of preservation natural environment. In consequence of cities expand across the planet, biological homogenization increases because the same urban-adaptable species become increasingly widespread and locally abundant in cities all around the World. Synantropic species adapted to intensely modified built habitats at the urban core are global homogenizers, that we found in cities and urban woodlands worlwide. This species consist of early successional plants and edge animal species as mesopredator mammals and frugivorous birds that can utilize gardens, forest fragmnents and many other habitats available in the suburbs. The intentional and unintentional importation of species adapted to urban habitats often produces local species diversity and abundance that is usually equal to or greater than the surrounding landscape. Human populations inhabit richly cultivated suburban habitats with a relatively high local floral nad faunal diversity without awerness of the global impoverishment caused by urbanization. Because so many urban species are immigrants...
|
|
|
Historical and present anthropogenic gradients in landscape
Staněk, Ondřej ; Klinerová, Tereza (referee) ; Vojta, Jaroslav (advisor)
My bachelor thesis is concerned in determining and classification of main anthropogenic influences in various ecosystems. Intensity and direction of landscape transformations such as nutrient income, terrain changes, disturbance, biomass removal or fragmentation is discussed and evaluated. Other landscape factors taking part in ecosystem endurance like different structure and pH of soils or various microclimatic conditions are also taken in notice. It seems that intensity of human influence varies depending on it's nature and it is difficult to propose a linear scale of these changes. From this point of view German hemeroby concept is discussed as possibly suitable scale of human influence. Historical and present anthropogenic gradients in landscape - Abstract (EN) Ondřej Staněk, 2010
|
|
|
Modelling of land cover change in abandoned landscape using time series of aerial photography
Brůna, Josef ; Jačková, Kateřina (referee) ; Vojta, Jaroslav (advisor)
Obsah 5 English abstract This thesis deals with modelling of land cover change in abandoned landscape. The study site is located in the military area Hradiště, around the former village Tocov, it is 2,5 km long and 2 km wide. Due to lack of historical vegetation data on landscape scale, historical aerial photographs were used as a primary source of data. They were orthorectified, mosaicked and automatically object oriented then classified in two categories woodland and grassland. Changes between two successive classified images were modelled with generalized linear models with mixed effects (lmer). Variables that were derived from digital elevation model, former land use and spatial variables computed with algorithms based on cellular automata were used. In order to verify the model predictions with the actual situation and for easier interpretation and visualization of results, a new application PEMZOK (Spatially explicit model of overgrowth of abandoned landscape) was developed and is one of the results of this work. Rapid rate of overgrowth of remaining grasslands was found. The largest observed effect on the spread of trees had the distance to the nearest tree or shrub and density of trees in the vicinity (15 m × 15 m) and the wider neighbourhood (105 m × 105 m). Models with these variables and land use...
|
|
| |
|
| |
|
| |
|
| |
|
| |
|
| |
guest ::
