Late Holocene Changes in Vegetation of the Mrągowo Lakeland (NE Poland) as Registered in the Pollen Record from Lake Salęt
Abstract Pollen analysis of sediments from the upper part of bottom deposits from Lake Salęt allowed reconstruction of main stages of the Late Holocene vegetation transformation in the Mrągowo Lake District (from ca. 3600 cal. years BC) and to correlate some of these changes with immigration and economic activity of local human groups. Significant spreading of secondary semi-natural birch forest, development of horn beam forest and increasing importance of anthropogenic open communities were the most characteristic features of vegetation evolution. A definite break down of elm took place between 2900 and 2500 cal. years BC, slightly after increased contribution of birch in wood lands. Disappearance of hazel around 1200 cal. years BC, accompanied by expansion of horn beam has been observed and should be linked with activity of the Ząbie-Szestno type culture and the Lusatian culture tribes during the Bronze Age, but not with a climate change. Considerable intensification of settlement processes recorded in the younger part of the Subatlantic chronozone was one of the important reasons that were responsible for quick changes in forest structure. Strong and continued deforestation started as early as the end of the 10th century AD and was substantially intensified in the first half of the 13th century.
Environmental changes and human activity 1 recorded in the gyttja-type bottom sediments of the Młynek Lake 2 ( Warmia and Masuria Region , northern Poland )
In the densely forested Warmia and Masuria region (north-eastern Poland) there are many lakes 18 characterized by small size, calm sedimentation and lack of tributaries, which makes them a very good 19 archive of environmental and paleoclimatic data for the Holocene. For this reason, one of them the Młynek 20 Lake, located near the village of Janiki Wielkie, has been selected for multi-faceted palaeoenvironmental 21 research based on a precise radiocarbon scale. Bottom sediments of this reservoir also contain unique 22 information about anthropopression, because a defensive settlement has been operating on its northern 23 shore since the early Iron Age to early Medieval period, which gives opportunity to correlate 24 paleoenvironmental data with phases of the human activity in the last 2400 years. Between 3rd – 2nd 25 century BC the lake was surrounded by a dense forest with domination of warm and wet climate conditions. 26 In turn of 2nd century BC and 2nd century AD forest around reservoir was much reduced, what can be 27 associated with the first early iron age occupation phase attested on the stronghold located close to the 28 lake. Between 2nd – 9th century AD gradual restoration of forest and decline of human settlements is 29 attested, along with lake deepening and onset of colder and humid climatic phase which correspond to 30 global cooling episode known as Bond 1 (1.5 ka BP). Period between 9th – 13th century AD indicates again 31 intensive forest clearing around the lake in result of human activity (Middle Age settlement phase on 32 stronghold). This period is characterized by climate change towards warming, which confirms the gradual 33 shallowing of the lake (Middle Age warming period). Since 13 up to 17th century AD intensive cultivation 34 activity around lake tool place. The landscape is subjected to strong human transformations which means 35 that environmental and climate changes are not so clear. However, changes in lake sedimentation can be 36 seen around 1500, which may be associated with so called Little Ice Age clod interval. 37 38 39
Palaeocarpinus (Extinct Betulaceae) from Northwestern China: New Evidence for Paleocene Floristic Continuity between Asia, North America, and Europe
Spiny-bracted fruits of Palaeocarpinus Crane, a genus of Betulaceae previously known only from Europe and North America, have been discovered in the Paleocene of Altai, northwestern China. The fruits are found in association with abundant Corylus-like foliage and staminate catkins containing Corylus-like pollen. Because of problems distinguishing leaves of Corylus from those of extinct betulaceous genera, we place these leaves in the genus Corylites Gardner ex Seward & Holttum. The fruits, staminate catkins, pollen, and leaves from Altai were probably all produced by a single species. Palaeocarpinus orientalis is nearly identical in its morphology to Palaeocarpinus joffrensis from the Paleocene of North America except in the more rounded primary bracts of the associated staminate catkins. The species is less similar to Palaeocarpinus laciniata from the Paleocene of southern England.