Tuesday, 16 December 2014

Archaeobotany: identification of vegetal macro remains from "Battaglia excavations" in Ledro

In this post I'm going to summarize the work of identification of vegetal non-woody macro remains from the so-called “Battaglia excavations” (1937) in Ledro lake pile dwelling (Tn, Italy).
The materials are stored in the Museum of Anthropology of Padua and appear to be fairly preserved. They are in most cases charred, rarely waterlogged. For this reason the preservation status (and therefore also the morphometric variation and the color) is not uniform.
The work of identification is preliminary to future aDNA studies, in collaboration with Edmund Mach Foundation.

Some of the vegetal remains from Ledro at the Museum of Anthropology of Padua
In the autumn of 1929, when the level of Lake Ledro was appreciably lower than usual, after thousands of years a lake-settlement re-emerged into the light of day. Along the southern shores of the lake a forest of wooden piles (10.000) broke the surface, bearing all the marks of their long immersion. At first they were thought to belong to some long-forgotten sluice built to control the level of the lake, but soon they revealed to be the remains of the largest prehistoric site to have been uncovered hitherto in Italy.
Then the water-level rose once more and all was submerged, until the drought of 1936-37 lowered significantly the level of the lake and enabled further excavation to be undertaken. These are the excavations known as “Battaglia”, from the surname of the archaeological director.
These first researches, made by the University and the archaeological service of Padua, saw the continuation in years ‘50 and ‘60. In the 80s, the Natural Science Museum of Trento realized campaigns of excavations with techniques previously not available, following the stratigraphic criteria and adopting scientific naturalistic methodologies, that allowed the experts to agree in thinking 2,200 BC to 1,350 BC the dates of these pile dwelling life.

For our project (December 2014), the identification of macro remains has been accomplished to the naked eyed and with the help of a microscope for the difficult ones.
For the comparison, illustrated volumes, paper and digital atlas (such as the Digital Atlas of Economic Plants in Archaeology of the Groningen Institute of Archaeology – GIA, University of Groningen and of the Deutsches Archäologisches Institut – DAI, Berlin) have been used.

In the analysis, approximately 750 remains have been studied: 533 certain, 24 uncertain and 194 undetermined.

Summary table of the non-woody macro remains
It is possibile to observe a lot of edible plants, some of them cultivated, others wild. Among the cultivated species we can recognize wheat (Triticum monococcum/dicoccum L.) and barley (Hordeum sp. L.). Their seeds are really abundant (in some cases there are also fragments of ears) and show signs of combustion.

Charred cereals
Then there are fruits of hazels (Corylus avellana L.) and oak/holm oak (Quercus sp.), certainly used in alimentation.

Hazels fruits
There are also some fruits belonging to the family Rosaceae, but it wasn't possible to determine gender and species. The small size allow to rule out the possibility of wild apple (Malus domestica) and the spherical shape is not suited to the wild pear (Pyrus communis L.) reported by Battaglia in 1943. One of the most plausible hypothesis is that it is Sorbus sp. L.
The high presence of dogwood (
Cornus Mas L.), of which only a part seems to have been preserved at the Museum (Battaglia wrote of an entire layer composed of these seeds, while those remaining are only a hundred), does suggest its use in a massive way in the food field. One hypothesis, with archaeological and ethongraphic evidence, is that the dogwood was fermented to make a low alcohoolic drink. 
Dogwood seeds
In addition to fruits and seeds, in the collection we can find some galls of oak (Quercus sp. L.). The gall, or cecidia, is a malformation that may be due to several causes; these galls seem to be originated by an insect, the Cynips quercusfolii. These remains may have been gathered by the lake-dwellers to derive the tannic acid, in which are rich, a substance used in tanning.

Galls of Quercus sp. L.
Extremely fascinating are the plant remains identified as mixtures of cereals, a kind of "dumplings" made by kneading a cereal flour coarsely chopped. The morphology is rounded, the "nuggets" seem to be made by flattening the mixture on the thumb and then cooked on hot stones (another theory, proposed by botanist Della Fior in 1940, which for now is to be considered merely hypothetical not being proven by scientific analysis, is that the internal cavity is the space for a filling of some kind).

The aspect relating to the alimentary economy is really meaningful, in particular the relationship between agricultural practices and gathering of wild vegetables. We can assume a certain balance in the use of both resources. Indeed, the environment offered many food resources that were certainly exploited by the inhabitants. The groups of herbaceous plants that characterize the wet grasslands and ruderal sites still provide an alternative and complementary source of food.

This project has been also an opportunity to make the first tests on geometric morphology techniques in archaeobotany using open-source softwares as MorphoJ. In future we will try to develop and make available these methodologies.
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