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Zprávy České botanické společnosti 40/2, 2005


Dančák M., Vašut R. J. & Trávníček B.
Příspěvek k poznání rozšíření ostružiníků v moravské části Českomoravské vrchoviny
Contribution to the knowledge of the distribution of brambles in the Moravian part of the Českomoravská vrchovina hills

The bramble flora of Western Moravia (Czech Republic) was studied. A total of 31 taxa (29 species) was recorded (including one hybrid) and the knowledge of the distribution of species in the studied area was considerably improved. A few species are mentioned for the first time from the territory of Moravia (Rubus franconicus, R. indusiatus and R. orthostachyoides, two latter each from a single locality in Moravia). Short notes on the character of distribution, a list of known localities and dot maps are presented in this paper.

Šumberová K.
Co víme o vegetaci tříd Isoëto-Nanojuncetea a Bidentetea v České republice?
What do we know about the vegetation of the classes Isoëto-Nanojuncetea and Bidentetea in the Czech Republic?

The vegetation of exposed pond bottoms belonging to the classes Isoëto-Nanojuncetea and Bidentetea was studied in the Czech Republic. In 1994–2004 a total of 947 phytosociological relevés were recorded and stored in the database TURBOVEG. These relevés come from 293 localities including fishponds, storage ponds (small ponds for the storage of marketable fish), alluvium deposits, sand pits, wet fields, etc. Data from floristic lists were added to the author’s relevés and used for comparison of the frequency of selected species and the construction of maps. The maps show the most interesting examples of geographical or habitat affinity of selected species. The present distribution of individual species and vegetation types of exposed pond bottoms in the Czech Republic is explained in relation to the biological features and ecological requirements of the individual species, to land use and habitat management. Attention is paid primarily to fishponds and storage ponds and the influence of fishpond management. Causes of the large variability in the Isoëto-Nanojuncetea and Bidentetea communities are explained. An understanding of these patterns is important for vegetation classification. Finally, the problem of the decline of some Isoëto-Nanojuncetea and Bidentetea species and perspectives for their survival in the present landscape is discussed.

Petřík P., Bílek O., Černý T. & Kolbek J.
Nelesní teplomilná vegetace povodí Mohelky v severních Čechách
Non-forest semi-thermophilous vegetation of the Mohelka river catchment area, North Bohemia

A field survey of non-forest semithermophilous vegetation in the Mohelka river catchment area (N Bohemia) was carried out, focusing on fringes (Trifolion medii) and on moderately to medium dry abandoned meadows (Arrhenatherion and Bromion erecti). Other non-forest vegetation was documented by means of phytosociological relevés: pioneer herb vegetation of primitive soils (Sedo-Scleranthetea), vegetation of acidophilous fringes (Melampyro-Holcetea mollis). Flora and vegetation were briefly described and the distribution of selected thermophilous communities was documented using maps. The study area represents a unique complex of man-made and semi-natural wet, mesic, and dry meadows.

Kolbek J., Boublík K., Černý T. & Petřík P.
Vegetační vazba druhu Cardaminopsis petraea v České republice
Vegetation with Cardaminopsis petraea in the Czech Republic

Vegetation preference of the species Cardaminopsis petraea in the Czech Republic was studied. Despite the fact that the species belongs to the rare taxa of the territory, a large ecological amplitude has been found as to its links to many vegetation units. Phytosociological material containing 68 of the authors’ own and 17 published relevés was classified subjectively into communities of 11 vegetation classes. In general, the species is linked with predominantly natural or seminatural heliophilous communities of drier to mesophilous habitats with a significantly greater affinity to acid and nutrient-poorer substrata. In the Czech Republic, its occurrence on limestone (reported from abroad) has not been documented. Cardaminopsis petraea occasionally occurs also in anthropogenic habitats (cultivated pine forests, on phonolite castle walls and on secondary grass slopes with scattered shrubs).

Navrátilová J. & Navrátil J.
Stanovištní nároky některých ohrožených a vzácných rostlin rašelinišť Třeboňska
Environmental factors of some endangered and rare plants in Třeboň’s mires

The importance of selected environmental factors for endangered and rare vascular plants and bryophytes were studied in non-forested mire vegetation on fishpond edges and spring fens in the Třeboň basin during the year 2004. The total of 28 endangered and rare vascular plants and 10 species of endangered and rare bryophytes were detected in 30 plots (16 m2 each) at 15 localities. Content of Ca2+ and Mg2+ and pH determined the species richness. High amounts of nutrients were detected in the plots periodically flooded by fishpond water and on the plots where the fen vegetation has been replaced by grasses and tall sedges.

Hédl R.
Co popisuje fytocenologie? (O některých nedostatcích středoevropské fytocenologie)
What is described by phytosociology? (Some weak points of Central European phytosociology)

The main weak points in Central European phytosociology methods are described and commented. First, preferential sampling design implies a twofold subjective classification already in the field. Subjectively distinguished and preferred vegetation types have been sampled, which distorts representativeness of the data, regarding the real vegetation. Second, vegetation has been changing continuously, while phytosociology gives a rather static description, being gradually overcome by changes. Third, classification based strictly on species composition makes phytosociology applicable only in some vegetation types, mostly the species-rich and ecologically specific ones. Finally, three controversial concepts of potential natural vegetation are briefly discussed. Objectivised vegetation sampling designs should be applied to assess the real abundance of vegetation types. A revision of the phytosociological system of vegetation units regarding vegetation changes should be carried out. Methods enabling a unified classification of floristically and ecologically unequal vegetation types should be developed. The present concept of potential natural vegetation seems to be speculative, requiring a re-evaluation.