Pollen analysis of the peat in a small mire on the northern slope of the Alborz Mountains (550 m a.s.l.) in the Central Caspian forests of Iran reveals changes in forest and wetland vegetation during the last millennium. A forest, principally of Alnus and Carpinus occurred over almost the whole period. Quercus, Ulmus and Parrotia were less common, while Fagus, Pterocarya, Acer and Diospyros fluctuated as a probable result of human interference and/or climatic change. Two phases of clay deposition in the mire can be dated to the `Mediaeval Climatic Anomaly' (AD 1100) and the beginning of the `Little Ice Age' (AD 1560—1600). Although human activity seems to have persisted in the region during the whole of the past millennium, increased NAP values point to intensified human interference since the beginning of the nineteenth century.

Aim To evaluate the biomization technique for reconstructing past vegetation in the Eastern Mediterranean–Black Sea–Caspian‐Corridor using an extensive modern pollen data set and comparing reconstructions to potential vegetation and observed land cover data. Location The region between 28–48°N and 22–62°E. Methods We apply the biomization technique to 1,387 modern pollen samples, representing 1,107 entities, to reconstruct the distribution of 13 broad vegetation categories (biomes). We assess the results using estimates of potential natural vegetation from the European Vegetation Map and the Physico‐Geographic Atlas of the World. We test whether anthropogenic disturbance affects reconstruction quality using land use information from the Global Land Cover data set. Results The biomization scheme successfully predicts the broadscale patterns of vegetation across the region, including changes with elevation. The technique discriminates deserts from shrublands, the prevalence of woodlands in moister lowland sites, and the presence of temperate and mixed forests at higher elevations. Quantitative assessment of the reconstructions is less satisfactory: the biome is predicted correctly at 44% of the sites in Europe and 33% of the sites overall. The low success rate is not a reflection of anthropogenic impacts: only 33% of the samples are correctly assigned after the removal of sites in anthropogenically altered environments. Open vegetation is less successfully predicted (33%) than forest types (73%), reflecting the under‐representation of herbaceous taxa in pollen assemblages and the impact of long‐distance pollen transport into open environments. Samples from small basins (<1 km2) are more likely to be reconstructed accurately, with 58% of the sites in Europe and 66% of all sites correctly predicted, probably because they sample an appropriate pollen source area to reflect regional vegetation patterns in relatively heterogeneous landscapes. While methodological biases exist, the low confidence of the quantitative comparisons should not be over‐emphasized because the target maps themselves are not accurate representations of vegetation patterns in this region. Main Conclusions The biomization scheme yields reasonable reconstructions of the broadscale vegetation patterns in the Eastern Mediterranean–Black Sea–Caspian‐Corridor, particularly if appropriate‐sized sampling sites are used. Our results indicate biomization could be used to reconstruct changing patterns of vegetation in response to past climate changes in this region.

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New pollen evidence from two sites in South-Central Zagros (Lake Maharlou), Southwestern Iran, and Sahand Mountains (Lake Almalou), Northwestern Iran, provide evidence for the emergence of tree cultivation in Southwestern Iran since the 3rd and 2nd millennia BC and upland agricultural activities in Northwestern Iran since 5th to 3rd centuries BC. Juglans cf. regia could have been cultivated fi rstly at ~2500 BC and became more extensively cultivated since ~1200 BC. Platanus cf. orientalis was also probably cultivated very early at ~1900 BC during the Middle Elamite period (2800-550 BC) and became more widely cultivated from ~1200 BC along with Juglans. The latter arboricultural events could have resulted from the establishment of great urban civilizations in Southwestern Iran. The rise of the Persian Empires seems to have been associated with a large-scale agricultural revolution over the Iranian Plateau. During the Persian Achaemenid Empire (550-330 BC) tree cultivation expanded in the Lake Maharlou area and agricultural practices expanded into upland areas in Lake Almalou area probably due to socioeconomic stability and the development of water exploitation and irrigation techniques. The Parthian (250 BC-225 AD) and Sassanian (224-642 AD) periods were also associated with tree cultivation practices in Lake Maharlou area but to a lower extent comparing to the Achaemenid period. In the Lake Almalou area, the Parthian period saw no spectacular agricultural event at least partly due to political and socioeconomic instability caused by confl icts with Romans over Armenia. The socioeconomic stability and further development in agricultural techniques during the Sassanian Empire could, however, favor again the large-scale tree cultivation practices in Northwestern Iran. The Post-Islamic period is characterized by reduced agricultural activities in the Iranian Plateau most probably due to political instability caused by numerous invasions by Arabs, Turks and Mongols. The last signifi cant agricultural event recorded in the Lake Almalou pollen record is the appearance of Ricinus communis cultivated since the beginning of the Safavid Empire (1501-1722 AD). Résumé : De nouvelles données polliniques provenant de deux sites dans les montagnes du Zagros (lac Maharlou, Sud-Ouest l'Iran) et de Sahand (lac Almalou, Nord-Ouest de l'Iran), apportent des indications sur l'émergence de l'arboriculture dans le Sud-Ouest iranien depuis les III e et II e millénaires av. J.-C., et sur les pratiques agricoles dans les hautes terres du Nord-Ouest iranien du V e au III e siècles av. J.-C. Juglans cf. regia fut probablement cultivé dès 2500 av. J.-C., puis plus extensivement à partir de 1200 av. J.-C. environ. Platanus cf. orientalis fut probablement cultivé précocement, vers 1900 av. J.-C., au cours de la période élamite moyenne (2800-550 av. J.-C.), et il devint plus largement cultivé à partir de ca. 1200 av. J.-C, parallèlement à la culture de Juglans. Ces innovations agricoles ont pu résulter du développement des grandes civilisations ...

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Predicting species‐level effects of climatic changes requires unraveling the factors affecting the spatial genetic composition. However, disentangling the relative contribution of historical and contemporary drivers is challenging. By applying landscape genetics and species distribution modeling, we investigated processes that shaped the neutral genetic structure of Oriental beech (Fagus orientalis), aiming to assess the potential risks involved due to possible future distribution changes in the species. Using nuclear microsatellites, we analyze 32 natural populations from the Georgia and Azerbaijan (South Caucasus). We found that the species colonization history is the most important driver of the genetic pattern. The detected west–east gradient of genetic differentiation corresponds strictly to the Colchis and Hyrcanian glacial refugia. A significant signal of associations to environmental variables suggests that the distinct genetic composition of the Azerbaijan and Hyrcanian stands might also be structured by the local climate. Oriental beech retains an overall high diversity; however, in the context of projected habitat loss, its genetic resources might be greatly impoverished. The most affected are the Azerbaijan and Hyrcanian populations, for which the detected genetic impoverishment may enhance their vulnerability to environmental change. Given the adaptive potential of range‐edge populations, the loss of these populations may ultimately affect the specie's adaptation, and thus the stability and resilience of forest ecosystems in the Caucasus ecoregion. Our study is the first approximation of the potential risks involved, inducing far‐reaching conclusions about the need of maintaining the genetic resources of Oriental beech for a species' capacity to cope with environmental change.

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Palynological analysis and radiocarbon dating of a short sediment core from a high-altitude mire in the Arasbaran area of northwestern Iran reveals long-term vegetation dynamics, climate change and anthropogenic impact. Our findings indicate the prevalence of semi-desert steppe vegetation, with a variety of Asteraceaemainly Lactuceaespecies from 3000 to 1440 cal yr BP. This period is followed by a higher occurrence of Artemisia spp. and Brassicaceae (1440-1330 cal yr BP), a re-expansion of Lactuceae (1330-1030 cal yr BP) and Brassicaceae (1030-330 cal yr BP) and, finally, Caryophyllaceae species (since 330 cal yr BP). The reconstructed millennia-long dry climate in the highlands of northwestern Iran is in good accordance with climate reconstructions from other east Mediterranean sites. Two phases of moister conditions between 2100-1400 and 1000-350 cal yr BP would correspond to altitudinal Quercus-Carpinus forest expansion in the Arasbaran area. The earliest indication of anthropogenic activity in the area dates back to the onset of the record, around 3000 cal yr BP. The occurrence of small maxima of Juglans regia, Corylus avellana and Cornus mas pollen at around 1350 cal yr BP is interpreted to reflect a temporary expansion of fruit cultivation. For the last millennium the occurrence of pollen attributable to Polygonum, Euphorbia, Plantago and Rumex suggests a diversification of steppe vegetation, which may reflect intensified agropastoral activities in the Arasbaran highlands. Based on our pollen record, the regional vegetation in the Kalan area remained largely stable over the last three millennia. However, changes in local hydrology caused substantial changes in wetland vegetation.