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Abstrakty/Abstracts

Zprávy České botanické společnosti 47/2, 2012


Abstrakty/Abstracts

Prančl J.
Rod Callitriche (hvězdoš) v České republice. I. Úvod a určování, druhy Chermaphroditica, C. hamulata aCpalustris
The genus Callitriche (water-starwort) in the Czech Republic. I. Introduction and identification, the species C. hermaphroditica, Chamulata and C. palustris

Abstract
The taxonomically challenging genus Callitriche, identification of its species, distribution and ecological demands were studied in the Czech Republic. An identification key of the species (including the first key ever produced for sterile plants) and their detailed descriptions are given. There are six species and one hybrid of Callitriche in the Czech Republic. This first part of the revision of the genus includes three species. The few localities of C. hermaphroditica subsp. hermaphroditica in Eastern and Central Bohemia are situated outside of its continuous distribution range in Europe. Unfortunately, this species is close to extinction in the Czech Republic. Callitriche hamulata is an aquatic plant typically growing in rivers and streams with clear water and a sandy bottom, but it is also abundant in stagnant waters at middle and higher altitudes. Its distribution in the Czech Republic has a somewhat Subatlantic tendency. Callitriche palustris occurs throughout the Czech Republic, with the centre of its distribution in pond-rich basins in Southern Bohemia, but never grows in running water there. Distribution maps of the three species are provided.

Dřevojan P.
Kozinec bezlodyžný (Astragalus exscapus) – dosud součástí flóry Znojemska
Astragalus exscapus – still a flora element of the Znojmo region, SE Czech Republic

Abstract
Astragalus exscapus was observed for the last time near the town of Znojmo (Czech Republic) in 1954 and was considered extinct until recently. In spring 2011, a small population of this rare species was discovered on a railroad embankment near the village of Dyje, probably at the same site as in the 1960s. The plants were confined to a small patch of dry grassland with Festuca valesiaca s. lat. and Poa angustifolia. This finding demonstrates the importance of neglected secondary habitats as potential sites for the survival of endangered species in the homogenized landscape of present times.

Kalníková V.
Rozšíření invazních neofytů podél toků severovýchodní Moravy a Slezska
Distribution of invasive neophytes along the streams in northeastern Moravia and Silesia

Abstract
In the summers of 2007, 2008 and 2009 I mapped the occurrence of invasive neophytes along the Morávka, Ostravice, Černá Ostravice, Bílá Ostravice, Baštice, Olešná, Bystrý, Čeladenka, and Mohelnice streams in NE Moravia and Silesia, Czech Republic. In total, 163 km of river courses were investigated. I focused on 39 species of invasive neophytes, most of them belonging to the Asteraceae family. The most abundant species growing along the streams were Solidago canadensis (86% of kilometre sections), Impatiens parviflora (85%), Reynoutria japonica (66%), I. glandulifera (60%), Juncus tenuis (58%), Erigeron annuus subsp. septentrionalis (57%) and Epilobium ciliatum (49%). The river sections in towns had more invasive species, than those outside of them, however these species were more abundant outside towns. All the surveyed streams were mapped from their sources to their confluence with rivers. Invasive neophyte species richness was mainly influenced by elevation: it strongly decreased towards higher altitudes. It also decreased in river sections with canyons or forests, but it incrased in towns, villages, in shrubby areas, in places with alluvial gravel accumulation and along regulated streams. The number of invasive species was also higher in river sections richer in habitat types.

Jehlík V., Jankovská V. & Moravcová L.
Erica tetralix v České republice
Erica tetralix in the Czech Republic

Abstract
Erica tetralix, a species with an Atlantic distribution within Europe (= Euro-Atlantic element) has been known from 16 localities in the Czech Republic since 1833 to the present. Most of them were only temporary synanthropic occurrences in forests, mostly in wet places. In natural habitats it currently grows only in three peaty and wetland localities in Bohemia (Malá Jizerská louka peat bog, Jizerské hory Mts., the Poselský pond within complex of Mariánský pond near Doksy-Obora and Mrtvý luh peat bog near Volary in the Šumava Mts.). It prefers localities with a more pronounced oceanic influence. The largest locality in Malá Jizerská louka peat bog (several hectares) is the nearest to the south-eastern border of its continuous distribution range in the Upper Lusatia (= Oberlausitz), therefore this occurrence can be considered more or less native, even though the origin of this locality was probably also anthropogenic. At this locality and also near the town of Doksy E. tetralix grows in peat bog vegetation of the association Scirpo-Sphagnetum papillosi Osvald 1923. Successful germination of mature seeds was demonstrated by a laboratory test, however seedlings have never been found in the studied stands. Based on the present vegetation conditions and taking in consideration the results of pollen and radiocarbon analyses, it is supposed that the occurrence of the species in the Malá Jizerská louka peat bog in Bohemia is not older than ca. 150–200 years. The beautiful and conspicuous E. tetralix shrublet should be recommended for strict legal protection in the Czech Republic.