National Repository of Grey Literature 96 records found  beginprevious87 - 96  jump to record: Search took 0.00 seconds. 
The invasive neophytes' occurrence in the riverbank vegetation
Matějček, Tomáš ; Lipský, Zdeněk (advisor) ; Mandák, Bohumil (referee) ; Lacina, Jan (referee)
Resumé The aim of this thesis is to summarize actual results of the field research of invasive neophytes' occurrence in the riverbank vegetation of selected water courses in the Czech Republic. In total approximately 850 km of the riverbank vegetation was mapped using author's own method. The riverbank vegetation was defined according to Novak et al. (1986) as the vegetation belt along a water course with boundaries represented by the water surface and the riverbank edge. The occurence of 22 most important invasive neophytes (sensu Pyšek et al. 2002) was registered using a logarithmical scale (1 = 1-9 specimen, 2 = 10-99 specimen, 3 = 100-999 specimen etc.). Some related species were not recognized (following species were aggregated together: Galinsoga parviflora and G. ciliata; Solidago gigantea and S. canadensis; Parthenocissus quinquefolia a P. inserta and Reynoutria japonica, R. sachalinensis and R. × bohemica). In total, occurence of 17 taxons was registered. The field research was conducted during the summer period of 2006, 2007 or 2008. Development in the years 2006 and 2008 could be compared for 218 segments, that was mapped in both time relations. The occurrence of invasive neophytes (17 taxons) was registered for each of the 500 m long segments (in total 1693 segments was mapped). The number of...
The invasive neophytes' occurrence in the riverbank vegetation
Matějček, Tomáš
The aim of this thesis is to summarize actual results of the field research of invasive neophytes' occurrence in the riverbank vegetation of selected water courses in the Czech Republic. In total approximately 850 km of the riverbank vegetation was mapped using author's own method. The occurrence of invasive neophytes (17 taxons) was registered for each of the 500 m long segments (in total 1693 segments was mapped). The number of specimen was registered using a logarithmical scale. Segments were defined using river navigation or important points of orientation (e. g. bridges or weirs). Total number of taxons, total number of specimen, simple index of invasive neophytes load (Is) and weighted index of invasive neophytes load (Iw) were calculated for each segment. The number of specimen was derived from registered values such as the mean value of the interval. The weighted index of invasive neophytes' load takes into account plant size, it's life history and potencial risk for indigenous flora or people and human activities. The number of specimen of each taxon is weighted by certain coefficient. The value of weighted index of invasive neophytes' load and some other characteristics are presented for parts of the water courses (i. e. groups of neighbouring segments with similar geographical and...
Noise in the environment from physical geography point of view
Křečková, Michala ; Matějček, Tomáš (advisor) ; Přibyl, Václav (referee)
This study investigates the sound propagation in the environment, defines sounds and related noise and describes their sources and features in general. The importance of noise as the environmental factor has shifted up sharply in the last decade and the sound propagation depends on many different circumstances. These factors, such as meteorological conditions, topography, ground cover or presence of vegetation cause changes in the sound propagation. Furthermore, nature itself can be also the place, where the sounds are generated. In the study were also listed impacts of sounds in landscape according to the origin (geophone, biophone and antrophone). In the practical part of this study the noise reduction effect of vegetation was investigated. More than 70 vegetations profiles with 43 vegetation species were covered and investigated. Six different kinds of vegetation were taken into account (conifers, broad-leaved trees, mixed forest, field thickets, herbs and belts of shrubs). To make comparison with the figures the last investigation was made in the open ground as the basic measure to compare the difference in sound pressure levels between the tree belts, theoretical attenuation and open ground. Point source of noise was set up in various distances in the front of the tree belts. Level of noise at various...

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