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Abstract Nowadays Najas flexilis is believed to be extinct in Poland, Germany, and Switzerland, while in other European countries it is classified as endangered or vulnerable. During the Early and Middle Holocene the species occurred throughout much of Europe, but in the Late Holocene it underwent a significant decline and reduction in range following, as it is believed, the gradual cooling of the climate and/or the eutrophication and acidification of lakes caused by human activity. The article recognizes the existence and disappearance of slender naiad in the palaeolake at the Hieronimowo site, NE Poland, during the Eemian Interglacial and at the beginning of the last glaciation (Vistulian, Weichselian), when lake transformations were caused solely by natural factors without human impact. Results of palynological and macrofossil analyses reveal that the appearance of slander naiad in the studied water body was probably triggered by the change of its pH and trophic status, resulting from the start of spruce and pine expansion stimulated by climate worsening during the younger part of the hornbeam phase (E5 R PAZ) in the middle Eemian. The appearance of spruce and pine in the area of the lake led to its acidification and oligotrophication, and that caused the strong and rapid development of N. flexilis. The species existed in the palaeolake at the Hieronimowo site through the spruce (E6 R PAZ) and pine (E7 R PAZ) phases, until the end of the Eemian Interglacial. These observations suggest that regressive transformations of the environment typical for the late part of the interglacial cycle, 'unsupported' by human activity, do not lead the extinction of N. flexilis. Quite the opposite, these processes promote this species. Its disappearance started only at the beginning of the Early Vistulian (Weichselian), and it was probably caused by a drastic decrease in temperatures and/or by the development of green algae, which limited light availability on the bottom of the water body. [ABSTRACT FROM AUTHOR]

The Beskid Niski Mts. and the foothill area of the Carpathians are under-represented in pollen data due to the unfavorable conditions for peat formation. This contribution is a review supplemented by new palaeobotanical data dedicated to the late Holocene history of local forests. Pollen, wood and other plant macrofossils as well as a new approach to isopollen mapping were used to reconstruct the migration of late-successional trees between ca. 3500 and 1900 BC. This time interval was define as a critical period in the development of the modern vegetation belts. We documented a quite late arrival of hornbeam, ca. 3500 BC, from the south and south east as well as optimal development of oak-lime-hornbeam forests forming the foothill belt between 2600 and 1600 BC. The migration of beech occurred ca. 3250–2750 BC and was followed by fir ca. 2800–2500 BC. Beech-fir forests already developed c. 2500 BC, and became common since ca. 1850 BC in the lower montane belt. On a regional scale, transformation of vegetation coincided with phases of climate moistening. The auxiliary role of the Corded Ware culture settlement, exploiting for the first time the upper landscape zone in the Carpathians, in the establishment of the new types of woodland, was indicated. Local differences in permanent deforestation of extensive areas were also analyzed. The beginning of this process in the lower landscape zone took place in the Roman Iron Age or in the Early Medieval time. In the upper landscape zone, it occurred in the Late Medieval or modern times, particularly as a result of the Wallachian colonization in the 15th and 16th century AD. [ABSTRACT FROM AUTHOR]

Laminated sediment records from several maar lakes and dry maar lakes of the Eifel (Germany) reveal the history of climate, weather, environment, vegetation, and land use in central Europe during the last 60,000 years. The time series of the last 30,000 years is based on a continuous varve counted chronology, the MIS3 section is tuned to the Greenland ice — both with independent age control from 14 C dates. Total carbon, pollen and plant macrofossils are used to synthesize a vegetation-stack, which is used together with the stacks from seasonal varve formation, flood layers, eolian dust content and volcanic tephra layers to define Landscape Evolution Zones (LEZ). LEZ 1 encompasses the landscape dynamics of the last 6000 years with widespread human influence. The natural oak and hazel forests of the early Holocene back to 10,500 b2k define LEZ 2. LEZ 3, the late glacial between 10,500 and 14,700 b2k, shows the development of a boreal forest with abundant grass and shallow water biomass in the lakes. The maximum of the last glaciation (LEZ 4: 14,700–23,000 b2k) was characterized by sparse vegetation of moss and characeae. These sediments are generally devoid of clay and sand and reveal no indication of snow-meltwater events. Accordingly, the Last Glacial Maximum (LGM) must have been extremely arid in central Europe. The sediments of the subsequent LEZ 5 from 23,000–28,500 b2k preserve distinct layers of clay and coarse sand, which indicates running water with clay in suspension and ephemeral coarse-grained fluvial sediment discharge. Abundant Ranunculaceae macroremains (used for 14 C dating), insects, moss and fungi sclerotia reflect a tundra environment during a time of frequent strong snowmelt events. Total carbon content, Betula–Pinus pollen and diatoms reach increased concentrations during Marine Isotope Stage (MIS) 3 interstadials that occurred between 28,500 and 36,500 b2k (LEZ 6). The entire MIS3 interstadials are well documented in the organic carbon record from the Auel dry maar. The main paleobotanical indicators of MIS3 are, however, grass pollen and heliophytes, which indicate a steppe environment with scattered/patchy trees during the interstadials. The stadial phases inferred during LEZ 6 reveal initiation of eolian dust deflation. The change of the early MIS 3 forested landscape to a steppe occurred with the LEZ 7–LEZ 6 transition. This is when modern man spread in central Europe. The principle vegetation change to a steppe at 36,500 b2k must have favoured the spread of horses, an important hunting prey of modern humans. We propose accordingly that the migration of the modern humans into central Europe might have been at least partly driven by climate and associated vegetation change. The LEZ 7 encompassed the time interval 36,500 to 49,000 b2k and was characterized by a boreal forest with high abundance of pine, birch, as well as spruce during the interstadial events. Abundant charcoal fragments indicate that this taiga was under frequent drought stress with regular burning. The most unexpected finding, but corroborated by all our maar records is the dominance of thermophilous tree taxa from 49,000 to 55,000 b2k (LEZ 8). Greenland interstadials 13 and 14 were apparently the warmest of MIS 3 according to the Eifel pollen records. The preceeding LEZ 9 from 55,000 to 60,000 b2k is also dominated by spruce, but thermophilous trees were sparse. A warm early MIS3 appears plausible, because summer insolation (at 60° N) was higher in the early MIS 3 than today, ice cover was low in Scandinavia and sea-surface temperatures of the North Atlantic were almost comparable to modern values during GI-14. [ABSTRACT FROM AUTHOR]

The present study is a review of the archaeobotanical analyses carried out in the last decade at the three ancient Roman port/dock system sites of Pisae , Portus , and Neapolis . Pollen, plant macrofossils (leaf, wood, seed/fruit macroremains) and wood constituting the shipwrecks were considered, and the results, partly unpublished, integrated and interpreted. Waterlogged sediments from these port areas turned out to be particularly suited for archaeobotanical analysis and opened new perspectives in ancient harbour studies. This is the first time that a synthesis of archaeobotanical data from Italian archaeological sites of the same typology is attempted for the Roman period. The disparate sampling strategies and available materials for macrofossil analysis in the various sites – cores in Portus , short sediment sequences in Pisae , and single visible hand-collected macroremains in Neapolis – conditioned the results obtained for these remains, making the comparison among sites a particularly difficult task. The urgency of establishing a common protocol between archaeologists and archaeobotanists is thus emphasized. The plant micro- and macrofossils highlight that in Roman times the landscape of the Italian coasts between Pisa and Naples was formed by deciduous oak plain forests (whose relicts are preserved in some protected areas, like in Parco Nazionale del Circeo, south of Rome and along the coast of the Pisan plain, in the Migliarino San Rossore Regional Park) with prevalence of mesophilous elements. The Mediterranean vegetation was not widespread as expected and maquis was limited to small areas by the coast. Surprisingly, mountain elements such as beech and silver fir were not so rare in pre-Roman times, suggesting that these trees could have occupied wider areas than at present. Besides food plant remains typical of the Roman age, the port sediments also preserved seeds, fruits and leaves of the wild vegetation. Comparing the results obtained by palynology with the shipwreck wood study showed that the boats were prevailingly built with local timber, often with conifers. The use of silver fir, though never very frequent, still confirms the preference of shipbuilders for this timber, which was not always available in the close surroundings of the three sites. [ABSTRACT FROM AUTHOR]

Against the background of climate change during the late Pleistocene and early Holocene, human society gradually transitioned from a hunting/foraging economy to an agricultural economy. The role of climate change in the development of millet-based agriculture, which originated in northern China, is of major scientific interest. Millet agriculture is thought to have originated in areas of hilly terrain, because most of the early millet agricultural sites in northern China occur in such areas. Hence, understanding the ecological background of hilly terrain during the early Holocene is important for understanding the climatic and ecological mechanisms associated with the origin of millet agriculture. In this study, we reconstructed the ecological background of Ping'an Cave, an early Neolithic site in the hilly area of Beijing, based on analyses of pollen, fungal spores, and plant macrofossils recovered from the cave sediments. At ~ 11,000 cal kyr BP, deciduous broadleaved forest-grassland developed in the hilly areas of northern China, where the climate was warm and relatively dry. Nut shells of Juglans and Celtis were found, associated with an increase in Quercus pollen, indicating the development of a wetter climate at ~ 8000 cal kyr BP. Open deciduous broadleaved forest–grassland was the main vegetation type in the hilly areas of northern China during the early Holocene. The geographical characteristics of these areas were favorable for prehistoric humans, providing ecological resources from both forest and grassland. • We investigated plant remains from Ping'an Cave site in hilly areas, northern China. • Deciduous broadleaved forest-grassland developed during early Holocene. • The vegetation became closer around 8000 years than it in 11,000 years. • Hilly terrain provided both forest and grassland resources for prehistoric humans. • This study offered ecological background for understanding millet agriculture origin. [ABSTRACT FROM AUTHOR]

The Roman port of Portus was the most important in the Mediterranean during the imperial period (27 BC–476 AD). It was made up of an outer port or Claudius basin and an inner hexagon or Trajan's port, joined by the Canale di Imbocco. The archaeobotanical record obtained in a continuos sediment core taken in this channel is made up of 19 types of plant macroremains, with a predominance of fibers of the seagrass Posidonia oceanica L., replaced by fluvial sediments in the upper part of the core. Seeds, fruits and thorns of aquatic species from marine or brackish waters, halophyte species, edible species, freshwater riparian vegetation and remains of charcoal and wood also appear regularly. According to the inferred palaeoenviromental evolution of this core, Portus was an area of fluvial-marine interaction during the Roman Empire, with brackish water conditions interrupted by stormy periods deduced from the record of P. oceanica. The archaeobotanical and sedimentary evolution points to a restriction of marine contributions and a final implantation of a fluvial environment. In this evolution, a specific interval with abundant charcoal and caryopses of Triticum could correspond to a fire, which was followed by a possible period of greater construction activity linked with large fragments of wood. • Fibers and Neptune balls of Posidonia oceanica dominated the filling of Portus. • The archaeobotanical record indicates an evolution from an initial marine domain to a final fluvial/anthropic phase. • High abundance of Neptune balls are tentatively correlated with stormy periods. • The joint presence of charcoal, caryopses of Triticum and larger wood fragments is associated with a fire. [ABSTRACT FROM AUTHOR]

Vegetation dynamics during the Pleistocene–Holocene transition and the beginning of farming are major topics for palaeoenvironmental sciences, especially interesting in ecologically sensitive areas, such as in North Africa. However, there are still important geographic and chronological gaps of environmental information in this region. Archaeobotanical record from Gueldaman GLD 1 deals with these issues, as it presents the longest archaeobotanical sequence available nowadays for Algeria, which includes these moments of major changes in landscapes. This topic has been approached from an interdisciplinary point of view, focused on the analysis of various types of plant remains that result in the reconstruction of both environment and use of plant resources. Results reveal the existence of a postglacial phase of plant colonization with Cupressaceae formations, which are gradually integrating some elements of sclerophyllous vegetation, such as several species of Pistacia , well documented both in charcoal and seed records. Neolithic levels show a shift in vegetation composition, as Olea europaea dominates the spectra, accompanied by strawberry tree and evergreen Quercus , among others. The presence of Olea in earlier chronologies has resulted from intrusions from the Neolithic levels: a set of radiocarbon dates has made it possible to evidence this process and detect the extent of the intrusions, which are inherent to cave records. • North Africa is a key region to know the dynamics of postglacial vegetation in the Mediterranean. • Gueldaman has provided archeobotanical information for a long sequence in Algeria. • Postglacial plant colonization and a later spread of sclerophyllous vegetation have been documented. • A taphonomic analysis has shown that the pre-Neolithic presence of Olea has resulted from intrusions from upper levels. • During Neolithic, Olea is a species of great economic relevance. [ABSTRACT FROM AUTHOR]