A three thousand year succession of plant communities on a valley bottom in the Vosges Mountains, NE France, reconstructed from fossil pollen, plant macrofossils, and modern phytosociological communities

Pollen and macrofossils were studied in a core from a fen at the foot of a slope in the Vosges Mountains, NE France. The present-day vegetation of little disturbed Abies, Fagus, and Picea forest and wetlands has been described in detail in terms of phytosociological communities using the Braun-Blanquet approach. Past ecological conditions are reconstructed in five steps: (1) The modern vegetation types are described as combinations of phytosociological species groups. (2) Micro- and macrofossils are assigned to these groups. (3) These in combination determine the past vegetation types at the site; there were simultaneously several such types in some biozones. (4) The sequence of past vegetation types is interpreted as successional pathways. (5) Past ecological conditions are inferred from these pathways. Results are: (1) The types of local forest and fen were the same around 1000 b.c. as today. (2) Rising groundwater around 650 b.c. caused a natural wet meadow to develop at the site. (3) Trees were felled near the site in the first century b.c. (Late Iron Age), facilitating the immigration of Picea. (4) Groundwater level rose during early Medieval times because of a wetter climate and alder carr replaced the dry-soil forest close to the site. (5) During High Medieval Times (10th-13th century) the nearby raised bog expanded over the site. (6) Forestry starting around a.d. 1750 caused nutrient-rich water to reach the site, resulting in abrupt vegetation change. (7) The creation of a forest road around a.d. 1855 (historical information) caused further nutrient enrichment of the site. The validity of the method used depends on the assumption that past and present vegetation types are virtually identical, which is true in our study area and study period, according to all the indications that we hav

The Lower Rhine (Germany) in Late Antiquity: a time of dissolving structures

From the middle of the 1(st) century AD, the Lower Rhine was part of the frontier of the Roman Empire (Limes). However, this Limes was not an impermeable line, but rather an open corridor that served as march area and as a trade and supply route for the adjacent military and civilian settlements as well as the hinterland. This required access to the river and permanent harbours. When planning military camps and towns along the Rhine, the existing topography and the challenge of a dynamic riverine landscape had to be taken into account. The prefered location for forts and towns were the raised edges of the Lower Terraces close to the undercut bank of a meander. For many years, research assumed that the river bend adjacent to a Roman site had to be an oxbow lake. The main argument being that only an oxbow situation would have protected the Roman sites against strong currents and the risk of demolition of land and settlements by the main stream (abandoned channel hypothesis). A re-evaluation of the extensive archaeological, sedimentological and palynological archive and published data from the Rhine plain, as well as of supplementary data from new boreholes, lead to a considerable increase in the previously incomplete knowledge of the fluvial history, especially regarding the timing of palaeomeander infilling. It showed that most of the meanders and river bends of the Rhine with Roman settlements on their banks not silted up before Late Antiquity (from the end of the 3(rd) century AD on). Before that those meanders were part of the main stream. The advantage of steep undercut banks was that a quay could be built on a location that ensured mooring all year round, even at low water level. However, it was necessary that stabilising bank protections were present in order to avoid shifting the course of the river with subsequent destruction of the infrastructure. Such an antique bank protection construction (a so called Packwerk) could be recognised in front of the Colonia Ulpia Traiana (CUT, Xanten). With this knowledge in mind, other excavated structures on the banks of palaeomeanders, previously mostly interpreted as Roman harbour remains, could be interpreted as bank protections. At Wesel near the strategically important mouth of the Lippe, the archaeological, sedimentological and palynological data showed that a meander that had silted up in Prehistoric times (Bronze Age) had been reactivated in Roman times and silted up again in Late Antiquity. A man-made diversion (perhaps by building a groyne) of the main stream could have been responsible for this. With the beginning of the Late Antiquity crisis of the Roman Empire at the end of the 3(rd) century, it presumably became increasingly difficult to maintain these water works. This enabled the river to regain its morphodynamics, by cutting of the meanders that were active during Roman times. We hypothesise that this increase in fluvial activities of the Lower Rhine from the end of the 3(rd) century onwards is due to an anthropogenic trigger: the collapse of the Roman Empire

The significance of chronology in the ecological interpretation of pollen assemblages of contrasting sites in the Vosges

Radiocarbon dates and pollentrends from sites within reference areas serve as a means for the establishment of a detailed chronology, on the basis of which pollen curves from contrasting sites can be compared at any cross section through time.Janssen Colin R., Braber F. I., Bunnik F. P. M., Delibrias Georgette, Kalis Arie J., Mook Willem G. The significance of chronology in the ecological interpretation of pollen assemblages of contrasting sites in the Vosges. In: Ecologia mediterranea, tome 11 n°1, 1985. Changements hydrologiques dans la zone tempérée au cours des quinze derniers millénaires / Paleohydrological changes in the temperate zone in the last 15000 years. Marseille (France) 3-5/07/1984. pp. 39-43

Geoarchaeological and archaeobotanical investigations in the environs of the Holsterburg lowland castle (North Rhine-Westphalia) - evidence of landscape changes and saltwater upwelling

The excavations at the Holsterburg site started in 2010 and revealed an octagonal castle from the medieval Staufer era of the 12th and 13th centuries AD of which only a few are known in Europe. The castle was built before 1170/1180 AD and its destruction is dated to 1294 AD. The site is located south of Warburg in North Rhine-Westphalia in the loess landscape of the so called Warburger Borde. As specific characteristic the castle is located in the midst of the floodplain of the Holsterbach which is a creek draining a small catchment towards the Diemel River valley. While archaeological investigations concentrated on the architecture and structure of the octagonal castle, geoarchaeological and archaeobotanical studies yielded substantial information on the hydro-geological characteristics of the castle subground and on the overall landscape evolution. The interpretation of earth resistivity transects in combination with vibracores showed that the castle was built on a construction layer which was founded on silt dominated alluvial and colluvial deposits within the valley bottom. This result is contrasting the former assumption that the castle was founded on gravels of the Weichselian Lower terrace. Geochemical studies of vibracore samples give evidence for salt enrichment within greyish laminated colluvial and alluvial deposits and for saltwater upwelling right underneath the castle. Most likely, these phenomena are due to the position of the castle in the midst of the Warburg fault system and to leaching processes bound to salt resources within the Rot or Zechstein formations in the subground. Archaeobotanical investigations by means of pollen analysis of samples from the castle infill and of core samples, both from below and above the construction layer, document a rapid accumulation of more than 3.5 m of sediments within less than 400 years prior to the construction of the castle. After its destruction in 1294 AD, the castle was filled up artificially with top soil material of the surrounding area

From point to area: Upscaling approaches for Late Quaternary archaeological and environmental data

The study of past socio-environmental systems integrates a variety of terrestrial archives. To understand regional or continental socio-environmental interactions proxy data from local archives need to be transferred to larger spatial scales. System properties like spatial heterogeneity, historical and spatial contingency, nonlinearity, scale dependency or emergence make generalizations from local observations to larger scales difficult. As these are common properties of natural and social systems, the development of an interdisciplinary upscaling framework for socio-environmental systems remains a challenge. For example, the integration of social and environmental data is often hindered by divergent methodological, i.e. qualitative and quantitative, approaches and discipline-specific perceptions of spatial scales. Additionally, joint approaches can be hampered by differences in the predictability of natural systems, which are subject to physical laws, and social systems, which depend on humans' decisions and communication. Here we present results from an interdisciplinary discussion of upscaling approaches in socio-environmental research with a special focus on the migration of modern humans in Central Europe during the last 30,000 years. Based on case studies from different disciplines, we develop a classification system for upscaling approaches used in past socio-environmental research. Finally, we present an initial upscaling framework that fosters the development of an interdisciplinary concept of scales and allows for a consideration of system properties like scale dependency, nonlinearity and contingency. The upscaling framework includes the following steps: i) the identification of relevant spatial and temporal scales at which socio-environmental interactions operate; ii) the definition of appropriate parameters to describe scale-specific interactions; iii) a comparison of process and observation scales to evaluate the potential of local archive data for larger scale generalization and for reconstructing scale-specific past socio-environmental interactions; iv) the identification and adaption of appropriate upscaling approaches for the relevant scales; v) the development of scale-specific models of socio-environmental interactions, and vi) the connection of models in a nested hierarchy. Our intention is not to present final results, but rather to stimulate future discussions and to provide a basic reference on scale issues in the emerging field of integrated socio-environmental research

Holocene vegetation succession and forest history in the upper Monts du Forez, Massif Central, France

On the basis of seven palynological records, we reconstruct the forest-limit composition and dynamics during the second part of the Holocene, in the upper montane and subalpine zones of the Monts du Forez in the north-eastern Massif Central, using a 2 km long, elevational transect of sites at 1335–1590 m elevation. All sites are mires today, varying in size from 2 to <0.1 ha. The chronology of the pollen diagrams is based on calibrated radiocarbon dating combined with pollen-stratigraphic correlation among the diagrams using the regional pollen component. Corylus avellana forest with Ulmus developed in the study region soon after the start of the Holocene. Soon after Fagus sylvatica arrived in the study area and expanded after ca. 3500 BC (5450 cal yr BP) to full abundance within a few centuries at the cost of Corylus. Abies alba expanded slowly within the Fagus forest after ca. 3300 BC (5250 cal yr BP), taking two millennia to reach its final abundance. During ca. 800–650 BC (2750–2600 cal yr BP) Fagus and Abies had reached similar overall abundances and formed forests only minimally affected by prehistoric human impact, which could serve as a natural baseline condition for extant forest management. We hypothesise that during this period dense Abies–Fagus krummholz had an upper limit of 1570 m, with scattered Abies trees above this and open woodland of Sorbus, Betula and Acer up to the summit (1634 m a.s.l.). A varied cultural landscape was in place in medieval times, with cereal cultivation and grasslands in a predominantly forested landscape. A baseline condition of this kind of cultural landscape could be found in late medieval times. During the last several centuries major deforestations took place and planted Pinus sylvestris replaced much of the originally natural Abies–Fagus forest. Crop cultivation increased in the cultural landscape. All diagrams have hiatuses (missing peat layers), which in most cases could be attributed to domesticated animals damaging the mire surface. For mire protection we therefore recommend a limited grazing pressure by cattle. The major phases in settlement history from the Neolithic to medieval times can be recognized in the pollen diagrams

Holocene vegetation succession and forest history in the upper Monts du Forez, Massif Central, France

On the basis of seven palynological records, we reconstruct the forest-limit composition and dynamics during the second part of the Holocene, in the upper montane and subalpine zones of the Monts du Forez in the north-eastern Massif Central, using a 2 km long, elevational transect of sites at 1335–1590 m elevation. All sites are mires today, varying in size from 2 to <0.1 ha. The chronology of the pollen diagrams is based on calibrated radiocarbon dating combined with pollen-stratigraphic correlation among the diagrams using the regional pollen component. Corylus avellana forest with Ulmus developed in the study region soon after the start of the Holocene. Soon after Fagus sylvatica arrived in the study area and expanded after ca. 3500 BC (5450 cal yr BP) to full abundance within a few centuries at the cost of Corylus. Abies alba expanded slowly within the Fagus forest after ca. 3300 BC (5250 cal yr BP), taking two millennia to reach its final abundance. During ca. 800–650 BC (2750–2600 cal yr BP) Fagus and Abies had reached similar overall abundances and formed forests only minimally affected by prehistoric human impact, which could serve as a natural baseline condition for extant forest management. We hypothesise that during this period dense Abies–Fagus krummholz had an upper limit of 1570 m, with scattered Abies trees above this and open woodland of Sorbus, Betula and Acer up to the summit (1634 m a.s.l.). A varied cultural landscape was in place in medieval times, with cereal cultivation and grasslands in a predominantly forested landscape. A baseline condition of this kind of cultural landscape could be found in late medieval times. During the last several centuries major deforestations took place and planted Pinus sylvestris replaced much of the originally natural Abies–Fagus forest. Crop cultivation increased in the cultural landscape. All diagrams have hiatuses (missing peat layers), which in most cases could be attributed to domesticated animals damaging the mire surface. For mire protection we therefore recommend a limited grazing pressure by cattle. The major phases in settlement history from the Neolithic to medieval times can be recognized in the pollen diagrams