DasCladonio rangiferinae-Pinetum sylvestris des Landschaftsschutzgebietes Křivoklátsko (Mittelböhmen) und seine Stellung im phytozönologischen System
The pine forest with an undergrowth of fruticose lichens—Cladonio rangiferinae-Pinetum sylvestris (Kobenza 1930) em.Passarge 1956 from the protected landscape area KřizoklätsCladonio-Pinetum comprises a permanent pine forest community occurring naturally on a hard base and nutrient deficient siliceous rocks in the semiconvex parts of the steep slopes of narrow side-valleys of the Berounka river. The soil type of this community is dystrophic ranker. The phytosociological composition of theCladonio-Pinetum is documented by the table of relevés, the habitat by chemical analyses of the soil.
The impact of forest management on changes in composition of terricolous lichens in dry acidophilous Scots pine forests
Abstract This study focuses on dry acidophilous Scots pine forests, well known for their high biodiversity of cryptogams. We hypothesized that dense forests and heavy management were responsible for changes in species diversity, decreasing trends in lichen cover and increasing moss cover. This hypothesis was tested in three types of Scots pine forests maintained under three different management regimes: 1) managed forests (forest plantations regenerated by planting), 2) semi-natural forests (forest plantations regenerated naturally), both located in the Borská nížina lowland in SW Slovakia, and 3) natural forests (primordial vegetation without visible management actions from the association Cladonio-Pinetum Juraszek 1928), located in the Bory Tucholskie National Park, NW Poland. We observed that the cover of the canopy tree layer had the most significant influence on the diversity of lichens. Managed forests are planted and maintained to achieve denser tree stocking, and although the environmental conditions created appear optimal for moss species, they are less suitable for terricolous lichens.
Live birth in the Devonian period
The extinct placoderm fishes were the dominant group of vertebrates throughout the Middle Palaeozoic era, yet controversy about their relationships within the gnathostomes (jawed vertebrates) is partly due to different interpretations of their reproductive biology. Here we document the oldest record of a live-bearing vertebrate in a new ptyctodontid placoderm, Materpiscis attenboroughi gen. et sp. nov., from the Late Devonian Gogo Formation of Australia (approximately 380 million years ago). The new specimen, remarkably preserved in three dimensions, contains a single, intra-uterine embryo connected by a permineralized umbilical cord. An amorphous crystalline mass near the umbilical cord possibly represents the recrystallized yolk sac. Another ptyctodont from the Gogo Formation, Austroptyctodus gardineri, also shows three small embryos inside it in the same position. Ptyctodontids have already provided the oldest definite evidence for vertebrate copulation, and the new specimens confirm that some placoderms had a remarkably advanced reproductive biology, comparable to that of some modern sharks and rays. The new discovery points to internal fertilization and viviparity in vertebrates as originating earliest within placoderms.