Erwan Messager

Archaeological Investigations at Chobareti in southern Georgia, the Caucasus

Once a restricted military zone, the Akhaltsikhe-Aspindza region within the Samtskhe-Javakheti province of Georgia is now the focus of archaeological investigations. This paper brings together the main data from three years of fieldwork at the ancient site of Chobareti, situated at 1610 metres above sea level, which has so far revealed a Kura-Araxes settlement and burials, and a late Antique/Medieval stronghold.

First results of archaeobotanical analysis from Neolithic layers of Buran Kaya IV (Crimea, Ukraine)

Abstract This paper contributes to understand the palaeoenvironment and the exploitation of vegetal resources during the Mid-Holocene in the southern Crimean Mountains. To address these questions, we apply a multi-proxy approach based on charcoal, seeds/fruits and phytoliths analyses from Neolithic layers (5800–5300 cal BC) of Buran-Kaya IV, a rock-shelter located in the south of Crimean Peninsula. Charcoal analysis shows that the Neolithic groups have exploited the Quercus petraeae forest belt composed mainly of Quercus, Carpinus and Acer. The identification of Fagus and a fragment of gymnosperm, which developed in upland areas, suggests the mobility of inhabitants of BK IV. According seed and phytolith analyses, it is more likely that the Neolithic groups did not practice agriculture on the site, and that their diet was not based on crop production. Furthermore, considering the probable absence of domestic animals in the layer 2, the economy may essentially be based on hunting-gathering at Buran Kaya IV.

DNA from lake sediments reveals long-term ecosystem changes after a biological invasion

Rabbits have had a stronger impact on the landscape and plant communities of a remote island than one century of climate change. What are the long-term consequences of invasive species? After invasion, how long do ecosystems require to reach a new equilibrium? Answering these questions requires long-term, high-resolution data that are vanishingly rare. We combined the analysis of environmental DNA extracted from a lake sediment core, coprophilous fungi, and sedimentological analyses to reconstruct 600 years of ecosystem dynamics on a sub-Antarctic island and to identify the impact of invasive rabbits. Plant communities remained stable from AD 1400 until the 1940s, when the DNA of invasive rabbits was detected in sediments. Rabbit detection corresponded to abrupt changes of plant communities, with a continuous decline of a dominant plant species. Furthermore, erosion rate abruptly increased with rabbit abundance. Rabbit impacts were very fast and were stronger than the effects of climate change during the 20th century. Lake sediments can allow an integrated temporal analysis of ecosystems, revealing the impact of invasive species over time and improving our understanding of underlying mechanisms.