Pollen and Charcoal Evidence for Human Responses to Climate Change in Mediterranean Environments
by
Laura Sadori
Dipartimento di Biologia Vegetale, Università "La Sapienza", Roma
Coauthors: Marco Giardini

Disentangling human from climatic impact is an everlasting minefield, in a matter where there is no easy solution. Abrupt climate changes is generally suspected to be the overriding factor.

The best potential to detect the cause of the landscape change comes from combining continuous records of proxy vegetation and climate change such as from lake cores obtained as close as possible to archaeological sites, which are the direct link to cultural history. Pollen and charcoal analyses from Holocene lacustrine sediment records of two extant Italian lakes (Lago di Pergusa, central Sicily, and Lago di Mezzano, northern Latium) of Mediterranean environments are used.

There is generally no doubt that major events were happening across a wide geographical range and relatively synchronously for which humans cannot have been responsible alone. Dramatic and rapid tree pollen concentration drops, not necessarily matching tree percentage decreases, have been pointed out during forest phases in many pollen diagrams of Latium during the last hundreds of thousands of years and interpreted as vegetation responses to climate changes. As similar drops are also found during the Holocene at Lago di Pergusa and at Lago di Mezzano the requirement of finding a reason to such changes induced to consider the possibility that human communities were the cause. But how could prehistoric populations have induced sudden, enduring, dramatic arboreal phytomass reductions on a large scale only by cutting trees? The necessity to investigate on past fires has become clear and checked using micro-charcoals as indicators of forest burnings.

During the Neolithic and Eneolithic periods, since ca. 8000 years ago, the plant macrofossil record shows that the agriculture was a common practice all over Italy and both Latium and Sicily were just in the same cultural development of the rest of the country. We should therefore expect that human impact on the landscape had markedly increased as populations expanded rapidly under conditions favourable to farming and life. The fact that even human presence alone is hardly detectable in Mediterranean environments until the Bronze age, and that in many sites a clear human impact is found only since the Roman periods, is incredible. Prehistoric populations did not produce strong changes on the landscapes, at least on a broad scale, and their influence has therefore to be found in lake archives very close to archaeological sites. Two arguments can be used to explain this lack of evidence and delay in proofs coming from Mediterranean pollen records: 1) the distance between lake and archaeological settlements; 2) the indigenous origin of many edible plants and the difficulty in identification of many anthropic indicators.

Date received: July 22, 2005

Copyright © 2005 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # caqy-50.