Palynologists study fossil pollen grains, deposited in lake/marsh sediments, to reconstruct past environment and long-term changes of vegetation. We would like to investigate the impact of human activities and climate fluctuations on the vegetation.

Our research is multidisciplinary, with widespread international collaboration activities. Changes of Lateglacial and Holocene vegetation in Slovenia, which were triggered by climatic fluctuations and human impact on the environment in various archaeological time periods, are being studied in Ljubljansko barje, v Julian Alps and Bela krajina regions of Slovenia.

Researchers: Maja Andrič, Nina Caf

Research areas in Slovenia

Ljubljansko barje

Ljubljansko barje is one of very few ‘long sequences’ in Europe where thick layers of Pleistocene sediments deposited for several 100 000 years. Also in much younger periods, e.g. in the Neolithic when the area was settled by pile dwelling settlements, pollen preservation in waterlogged sediments is excellent. By analysing fossil pollen in sedimentary cores and stratigraphic columns from archaeological sites, we can reconstruct forest composition, landscape openness and human impact (forest clearance and burning) due to agriculture and animal husbandry.

At the end of the last Ice Age predominantly pine-birch woodlands were growing around the former lake at Ljubljansko barje. At the beginning of the Holocene about 11 700 years ago climate became warmer and wetter and the lake was surrounded by mixed, predominantly broadleaved forest with oak, elm, lime, ash and hazel. Beech forests spread early in the Holocene, whereas fir-beech forests started to dominate ca. 9000 years ago, presumably due to wetter climate. At about 6750-6000 BP climate probably became slightly drier, lake shallower, beech-fir forests retreated. Afterwards beech and fir expanded again, presumably due to wetter and colder climate. Human impact (forest clearance) became significant in the 4th millennium BC, when the area was settled by numerous Neolithic pile dwelling settlements.

Neolithic inhabitants of Ljubljansko barje, who needed open areas for farming were cutting and burning forests to create fields and pastures. Thus the forest composition changed: shade-tolerant beech and fir became less abundant, whereas hazel, oak and hornbeam became more widespread. Oak wood was also used for construction of houses. In archaeological cultural layers of pile dwelling settlements, which are dated to the 4th millennium BC, plant macrofossils and pollen of cultivated plants (e. g. cereals and flax), were discovered.

In the 18th and 19th centuries AD peat at Ljubljansko barje was cut and burnt to drain the area. In this way palaeoecological record in younger layers of the Holocene (i.e. last 4500 years) was destroyed throughout most of the Ljubljansko barje. Therefore, information about the vegetation history in the last few millennia is preserved only in few places (e.g. at Podpeško jezero, Mali plac, Jurčevo šotišče).

 

Selected bibliography

Andrič M. 2020 (in print). Maharski prekop, Stare gmajne and Blatna Brezovica settlements and the vegetation of Ljubljansko barje (Slovenia) in the 4th millennium cal. BC, Documenta Praehistorica 47.

Andrič M., Tolar T., Toškan B. 2016. Okoljska arheologija in paleoekologija: palinologija, arheobotanika in arheozoologija, Ljubljana.

Golyeva A., Andrič M. 2014. Palaeoecological reconstruction of wetlands and Eneolithic land use in Ljubljansko barje (Slovenia) based on biomorphic and pollen analysis, Catena 112, 38-47.

Andrič M. 2009. Holocenske paleoekološke in paleohidrološke razmere na Ljubljanskem barju – prispevek k diskusiji. / The Holocene palaeoecological and palaeohydrological conditions at Ljubljansko barje – a contribution to discussion. Arheološki vestnik 60: 317-331.

Andrič M., Kroflič B., Toman M. J., Ogrinc N., Dolenec T., Dobnikar M., Čermelj B. 2008. Late Quaternary vegetation and hydrological change at Ljubljansko barje (Slovenia), Palaeogeography, Palaeoclimatology, Palaeoecology 270, 150-165.


Ljubljansko barje

 

Julian Alps

In the last few years palynological research focused on multi-proxy palaeoenvironmental studies of the Julian Alps (Triglav lakes, Lake Bled, Lake Bohinj, Šijec peat bog).

Palaeoecological research of the sediment which deposited in the Lake Bled towards the end of the last Ice Age enabled the reconstruction of climatic fluctuations and changes of vegetation between ca. 20 000–10 000 cal. BP. Thin layers of microscopic volcanic ash deriving from Italian and Icelandic volcanos were also discovered. Currently, pollen in younger sediments, which deposited in Lake Bled and Šijec peat bog in the last 10 000 years is being investigated.

In 2012 a 12m deep sedimentary core was collected in Lake Bohinj. In the upper 4.5 m of the core a multidisciplinary international team of researchers investigated ca. 6600 years long record of geological processes and human impact on the vegetation. Pollen, sedimentological and geochemical characteristics of the sediment indicate that the vegetation and sediment composition were affected by climatic fluctuations. Layers, rich in flysch material formed in the periods of wetter climate, when water was coming to Lake Bohinj not only from the west (Savica, current situation), but also from the eastern part of the watershed. Seismic events (very strong earthquake was detected at 6600 yr cal. BP) reworked previously deposited sediment, therefore earthquake history in the last 6600 years was reconstructed. First traces of human impact on forest composition were detected in the Bronze Age, when fir started to decline due to grazing. In the Iron Age at ca. 2600 yr cal. BP (600 yr cal. BC) people were cutting/burning forest, which in addition to wetter climate, triggered massive soil erosion.

Mountain areas of Julian Alps are palynologically mostly unexplored and we do not know what was human impact on the environment and which natural resources were exploited. Two sedimentary cores were collected in lakes ‘jezero na Planini pri jezeru’ (Lateglacial and entire Holocene) and ‘jezero v Ledvicah’ (last 6000 years). Palynological, geochemical and mineralogical research of these cores aims to investigate what was the impact of climate fluctuations and human activities on the environment of the mountain areas.

Selected bibliography

Andrič M., Sabatier P., Rapuc W., Ogrinc N., Dolenec M., Arnaud F., von Grafenstein U., Šmuc A. 2020. 6600 years of human and climate impacts on lake-catchment and vegetation in the Julian Alps (Lake Bohinj, Slovenia). Quaternary Science Reviews 227.

Rapuc W., Sabatier P., Andrič M., Crouzet C., Arnaud F., Chapron E., Šmuc A., Develle A-L., Wilhelm B., Demory F., Reyss J-L., Régnier E., Daut G., von Grafenstein U. 2018. 6600 years of earthquake record in the Julian Alps (Lake Bohinj, Slovenia). Sedimentology 65, 2018, str. 1777-1799, doi: https://doi.org/10.1016/j.quascirev.2019.106043. [COBISS.SI-ID 1378398].

Lane, C., Andrič, M., Cullen V. L., Blockley S. P. E. 2011. The occurrence of distal Icelandic and Italian tephra in the Lateglacial of Lake Bled, Slovenia. Quaternary Science Reviews 30, 1013–1018.

Andrič, M., C. Lane 2011, Vulkanski pepel in pelod iz Blejskega jezera, Gea 21, okt. 2011, 10–11.

Andrič, M., J. Massaferro, U. Eicher, B. Ammann, M. C. Leuenberger, A. Martinčič, E. Marinova, A. Brancelj, 2009. A multi-proxy Late-glacial palaeoenvironmental record from Lake Bled, Slovenia, Hydrobiologia 631, 121-141.


Julian Alps

Bela krajina

Palynological research of two small marshes in the vicinity of Mali Nerajac (Mlaka) and Griblje villages indicated that the vegetation of Bela krajina was significantly shaped by people. In the beginning of the Holocene ca. 10 000 years ago a mixed woodland of lime, hazel, oak, birch and pine was growing in the region. At ca. 8900 yr cal. BP climate presumably became wetter and thick, predominantly beech forest spread. At 7800 yr cal. BP beech became less widespread: it is not clear whether this vegetation change is associated with drier climate or human impact. In the subsequent centuries forest recovered through phases of hazel, oak and hornbeam woodland.

The impact of first, Neolithic farmers was detected from at least ca. 6000 yr cal. BP. At 5800 yr cal. BP (i.e. 3500 yr cal. BC) people were burning forest and first pollen of cerals and plants characteristic for grazing areas, fields and ruderal surfaces (e.g. ribwort plantain, cornflower, mugwort, goosefoot) appear on pollen diagrams. In the subsequent centuries beech forest recovered (in some periods even fir-beech forests spread), but periods of more/less intensive human impact on the environment (forest clearance and burning) continued. Human impact on the vegetation in the last 6000 years significantly affected biotic diversity and led to formation of mosaic landscape. Beech (and fir) forests were more widespread than today, when litter raking forests with birch and bracken, oak and hornbeam forests prevail.

Bela Krajina is very old cultural landscape therefore it is difficult to estimate what potential natural vegetation would grow there if there would be no human impact. How far back in the past one should return to see ‘natural’ vegetation? Under the same climatic conditions as today? Based on the results of palynological research we can assume that with moderate human impact on the environment biodiversity increased and mosaic landscape formed. If there would be no human impact and no global warming, hornbeam or even beech or beech-fir forest can spread rather soon.

Selected bibliography

Šilc, U., M. Andrič 2012. Dolgoročen vpliv človeka na biotsko raznovrstnost: Primerjava fitocenoloških in palinoloških rezultatov (Bela krajina) / Long-term impact of man on biodiversity. A comparison of phytocoenelogical and palynological results (Bela krajina) , in: Andrič M. (ed.). Dolgoročne spremembe okolja, Opera Instituti Archaeologici Sloveniae 25, 55-61, Ljubljana.

Mason, P., M. Andrič 2009. Neolithic/Eneolithic settlement patterns and Holocene environmental changes in Bela krajina (South-Eastern Slovenia). Documenta Praehistorica 36: 327-335.

Andrič, M. 2008. Pelod razkriva preteklost Bele krajine, Proteus 70 (9/10), maj-jun. 2008, 413-420.

Andrič, M. 2007. The Holocene Vegetation Development in Bela krajina (Slovenia) and the Impact of Fist Farmers on the Landscape, The Holocene 17(6), 2007,763-776.

Andrič, M., K. J. Willis 2003. The Phytogeographical Regions of Slovenia: a Consequence of Natural Environmental Variation or Prehistoric Human Activity? Journal of Ecology 91: 807-821, 2003


Bela krajina

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