Late-glacial Forest Research Articles

Evidence for the diet and habitat of two late Pleistocene mastodons from the Midwest, USA

AbstractWe analyzed intestinal contents of two late-glacial mastodons preserved in lake sediments in Ohio (Burning Tree mastodon) and Michigan (Heisler mastodon). A multi-proxy suite of macrofossils and microfossils provided unique insights into what these individuals had eaten just before they died and added significantly to knowledge of mastodon diets. We reconstructed the mastodons’ habitats with similar multi-proxy analyses of the embedding lake sediments. Non-pollen palynomorphs, especially spores of coprophilous fungi differentiated intestinal and environmental samples. The Burning Tree mastodon gut sample originates from the small intestine. The Heisler mastodon sample is part of the large intestine to which humans had added clastic material to anchor parts of the carcass under water to cache the meat. Both carcasses had been dismembered, suggesting that the mastodons had been hunted or scavenged, in line with other contemporaneous mastodon finds and the timing of early human incursion into the Midwest. Both mastodons lived in mixed coniferous-deciduous late-glacial forests. They browsed tree leaves and twigs, especiallyPicea. They also ate sedge-swamp plants and drank the lake water. Our multi-proxy estimates for a spring/summer season of death contrast with autumn estimates derived from prior tusk analyses. We document the recovered fossil remains with photographs.

Interstadial inland dune slacks in south-west Slovakia: a multi-proxy vegetation and landscape reconstruction

Palaeoecological studies spanning back to the Bølling/Allerød (GI-1) Interstadial of the Late Glacial in the whole Western Carpathians and adjacent lowlands are extremely scarce. To improve our knowledge about the landscape structure and diversity of wetland habitats, we analysed two palaeoecological interstadial sequences of pollen and macrofossils (bryophytes, vascular plants and molluscs) from the sandy landscape of the Borská lowland (southwest Slovakia). The deposits differed between the two sequences analysed, consisting predominantly of lacustrine chalk or brown-moss sedge fen peat, respectively. The results showed that, during wetter and warmer conditions during the Interstadial, open large dunes had been stabilised by pine woodlands admixed by birch. Contrary to the Podunajská lowland, which is situated eastwards towards the centre of the Pannonian Plain, broadleaf thermophilous trees such as Ulmus, Quercus and Tilia were almost absent in the study region, which suggests an importance of the bedrock for Late-Glacial forest vegetation. Salix, Alnus and Betula nana scrubs were probably scattered across wetlands. Active dunes were occupied by Hippophaë rhamnoides and steppe vegetation with grasses, Artemisia and Helianthemum. Low abundance of Chenopodiaceae pollen suggests that the sandy bedrock was probably unfavourable for the development of salt-rich habitats. Wetland habitats were diverse and abundant in the inter-dune space, partly resembling recent coastal dune slack vegetation or alluvial salty grasslands in continental central Asia. The wetland habitats comprised aquatic habitats with Myriophyllum, Potamogeton filiformis, P. pectinatus, P. pussilus, Sparganium minimum and planktonic algae (Pediastrum and Botryococcus), strongly continental calcareous-fens with Blysmus rufus and Triglochin maritima, boreocontinental brown-moss sedge fen fens with Drepanocladus trifarius, Carex lasiocarpa, Menyanthes trifoliata and Scorpidium scorpioides) and reed beds with Cicuta virosa, Phragmites and Schoenoplectus tabernaemontani. Remains of these unique wetland mosaics have recently disappeared because of human activities including peat extraction and dune stabilisation by pine plantations, which have transformed the modern landscape.

Substrate dependency of Lateglacial forests in north‐east Germany: untangling vegetation patterns, ecological amplitudes and pollen dispersal in the past by downscaling regional pollen

AbstractAim Palynology has revealed that during the Lateglacial Allerød period, Pinus and Betula dominated the forests of north‐east Germany. Because of implicit restrictions, however, palynology fails to reconstruct in detail the distributional patterns and whether monospecific or mixed forests prevailed. Here we test the hypothesis that the distributional patterns of Pinus and Betula were largely determined by substrate.Location Fifteen sites in north‐east Germany.Methods As pollen data reflect the abundance of taxa around a sample site, our hypothesis implies that the abundance of e.g. Pinus pollen should reflect the abundance of substrate types that are favoured by Pinus. (In order to differentiate clearly between taxa and pollen types, the latter are displayed in small capitals.) We analysed the percentage of Pinus and Betula pollen from an interval in the Allerød, and their relationship to the present‐day proportion of the two dominant substrate types (sand and boulder clay). The substrate proportion was determined in rings from 1 to 50 km around all sites, using four distance‐weighting functions.Results Pollen percentages of Pinus are linearly related to the proportion of sand, and Betula percentages to the proportion of boulder clay. The highest coefficients of determination (r2 = 0.89 and 0.91, respectively) were observed for radii of c. 30 km, with distance weighting by 1 and 1/d.Main conclusions The present‐day distributional pattern of substrate types strongly indicates the distributional pattern of Pinus and Betula in north‐east Germany in the Allerød. Assuming that the pattern of substrates remained broadly constant, Pinus dominated on sand and Betula on boulder clay. Our new method thus enables us to refine significantly the reconstruction of habitat characteristics and distributional patterns of taxa in the Lateglacial and Holocene, independent of their present‐day ecological amplitudes. The good performance of the distance‐weighting functions 1 and 1/d indicates that the pollen source area of a site has rather discrete boundaries determined by convective air movements during daytime. Within these boundaries, pollen is evenly distributed over various distances. This implies that light pollen types are transported further than predicted by Sutton’s equation on particle dispersal.

A 12,000-Year Pollen Record from Lake Maliq, Albania

Pollen data from Lake Maliq, the first from Albania, contribute new information to the discussion of the vegetational, hydrological, and climatological history of the Balkans since 12,000 yr B.P. During late-glacial time, a perennial lake expanded at Maliq. It was surrounded by a complex vegetation association composed of steppe and mixed forest elements. The highly diverse forest flora suggest that late-glacial forest refugia were more developed here at middle altitude, rather than at higher altitude as previously suggested. The forest developed after 9800 yr B.P., while the water level remained high in the Korçë basin until 5000 yr B.P. Different environmental conditions, characterized by lower available moisture and warmer winters, progressively took place after this date. Human activity in the Korçë basin ca. 4500 yr B.P. was coeval with conditions characterized by an increase in winter temperatures and a decrease in summer moisture.

Influence of human impact and bedrock differences on the vegetational history of the Insubrian Southern Alps

Vegetation history for the study region is reconstructed on the basis of pollen, charcoal and AMS14C investigations of lake sediments from Lago del Segrino (calcareous bedrock) and Lago di Muzzano (siliceous bedrock). Late-glacial forests were characterised byBetula andPinus sylvestris. At the beginning of the Holocene they were replaced by temperate continental forest and shrub communities. A special type of temperate lowland forest, withAbies alba as the most important tree, was present in the period 8300 to 4500 B.P. Subsequently,Fagus, Quercus andAlnus glutinosa were the main forest components andA. alba ceased to be of importance.Castanea sativa andJuglans regia were probably introduced after forest clearance by fire during the first century A.D. On soils derived from siliceous bedrock,C. sativa was already dominant at ca. A.D. 200 (A.D. dates are in calendar years). In limestone areas, however,C. sativa failed to achieve a dominant role. After the introduction ofC. sativa, the main trees were initially oak (Quercus spp.) and later the walnut (Juglans regia). Ostrya carpinifolia became the dominant tree around Lago del Segrino only in the last 100–200 years though it had spread into the area at ca. 5000 cal. B.C. This recent expansion ofOstrya is confirmed at other sites and appears to be controlled by human disturbances involving especially clearance. It is argued that these forests should not be regarded as climax communities. It is suggested that under undisturbed succession they would develop into mixed deciduous forests consisting ofFraxinus excelsior, Tilia, Ulmus, Quercus andAcer.

Phytoliths from Archaeological Sites in the Tropical Forest of Ituri, Democratic Republic of Congo

Phytoliths record late Quaternary vegetation at three archaeological sites in the Ituri rain forest. The oldest deposits, dated to ca. 19,000 to 10,000 14C yr B.P., contain abundant phytoliths of grasses but also enough arboreal forms to show that the landscape was forested. The late-glacial forests may have had a more open canopy than today's. Younger phytolith assemblages show that the northeast Congo basin was densely forested throughout the Holocene. Archaeological materials among the phytoliths show that people lived in this region during the Pleistocene. Therefore, Pleistocene and Holocene prehistoric foragers probably inhabited tropical forests of the northeast Congo basin many millennia before farming appeared in the region.

First report on new evidence for the occurrence of Podocarpus and possible human presence at the mouth of the Amazon during the Late-glacial

Palynological studies on late Quaternary lake sediments from the region of the Amazon estuary, 100 km north-east of Belem, Para State, Brazil, enable reconstruction of lowland Amazonian rain forest during the Late-glacial and Holocene periods. Late-glacial forests included populations of Podocarpus which suggests a distinct climatic cooling. Ilex was abundant in the early Holocene. Records of the mangrove taxon, Rhizophora, indicate rapid Atlantic sea-level rise in the beginning of the Holocene. High charcoal representation may reflect the first arrival of Amerindians in the Amazon coastal area, probably about 10 800 B.P.

Late-Quaternary climate in the Ridge and Valley of Virginia, U.S.A.: Changes in vegetation and depositional environment: A contribution to the ‘North Atlantic seaboard programme’ of IGCP-253, ‘Termination of the Pleistocene’

Browns Pond, Virginia, in the Ridge and Valley physiographic province, contains a record of changing vegetational and depositional environments that dates to 17,130 BP. Six cores were retrieved in a transect of the pond. Pollen and macrofossils were identified from the longest central core and a series of AMS radiocarbon dates obtained from identified macrofossils and sediment. The pollen and macrofossil record combined with laterally consistent changes in lithostratigraphy reveal a changing climate. From 17,300 to 14,100 BP, a closed boreal forest of Pinus-Picea-Abies grew at the site. Pinus dominates the pollen assemblage while Picea and Abies dominate the macrofossil assemblage. Subtle increases in more thermophilous and mesophytic taxa indicate gradual climate amelioration after the full-glacial. A marked increase in Alnus at 14,100 BP signals an increase in moisture, possibly related to the global evidence for rapid climate change at 14,000 BP. At this central Appalachian site, Abies and Alnus are found in relatively greater amounts in the late-glacial forest than previous studies indicated. Low organic contents and evidence of gleyed conditions, seen in the core transect from 10,000 to 8000 BP, point towards low-water levels in the early Holocene—approximately coincident with the expansion of Quercus.