Laboratory of Archaeobotany and Palaeoecology

Archaeobotanical Summer School in Ohrid, Republic of North Macedonia as part of the international research project Frontier Studies

duration: 2019-present

The archaeobotanical summer school has a long tradition. Its main meaning is connecting natural science with archaeology, especially with the fields of archaeobotany. Students of botany and archeology from the Faculty of Sciences and the Faculty of Arts of the University of South Bohemia are trained directly within the framework of several research projects, in this case within the framework of Frontier Studies.

Frontier Studies is an international research project focused on the city of Ohrid and its surrounding landscape and environment. It is situated on the northern shore of the Ohrid  lake in the border region of Albania and North Macedonia. Since the start of the project in 2017, the research effort has been defined by the collaboration between Charles University in Prague (Marek Verčík, ÚKAR FF UK) and the Archaeological Museum in Skopje (Pero Ardjanljev), since 2019 also with the Czech Geological Survey (Jan Hošek) and the University of South Bohemia in České Budějovice (LAPE). The goal of the first research season, supported by the summer school of archaeobotany at the University of South Bohemia, was an extensive field survey of the historical landscape and research of the region's settlement structures dynamics, captured in the developmental sequence.

The task of the summer archaeobotanical school in this project is to obtain and provide primarily archaeobotanical data, used to explain landscape and ecological questions, focused on historical microenvironments, interesting for the description of vegetation in individual phases of the development of prehistoric and ancient settlements. The specific goal is also to create a reference database for further reconstructions.

In the first year of the project, the participants of the summer school participated in the testing of several locations (Trebeniste, Grasinca I/II, Daljan, Gorno Lakocerej- Tri topoli, Bobansko ezero) by means of geological probes with an excavator or a drilling rig. These four localities were sampled. Samples were subjected to analysis of plant macroresidues, wood and carbons, AMS radiocarbon dating, pollen analysis and other methods…

The analyzes have already provided interesting results. We are not only surprised by the presence of a round settlement from Grašnice (from Late Antiquity), but above all by the evidence of an organic layer from the Younger Bronze Age based on a geological probe, whose existence under the thick lake sediment testifies to a significant tectonic event. The analyzes that are carried out confirm the dating of the ceramic fragments to the end of the Younger Bronze Age. However, they also capture the state of the landscape at the end of the prehistoric period, when the central settlement in Ohrid was surrounded by the water of the lake and coastal lagoons.

Laboratory of Archaeobotany and Palaeoecology

Archaeolozoology is a scientific discipline which refers to the study of animal remains (bones, teeth, horny tissue, conches of molluscs etc.) from archaeological sites. The goal of archaeozoology is to gain and to better understand the relation between humans and animals in the past. Archaeozoology links up the archaeological informations with the results of zoological analysis. This connection can bring valuable conclusions about human nutrition because a meat formed an important component of diet next to the plants. Some animals did not serve only for the consumption purpose, they were unexpendable in the social affiliation and belief systems or they were breeded as pets for an emotional support and used for other products (fur, wool, milk, force etc.). The archaeozoological research is focused both on the macroscopic tissues of vertebrate and invertebrate and on their DNA, the traces elements or the stable isotopes contained in the bones and teeth.

Fragments of diaphyses of long bones of large mammals, which represented a suitable raw material to produce bone buttons. Photo: L. Kovačíková

The archaeozoological research is primarily based on identification, analysis and interpretation. The identification stage can be equated with collecting primary data (taxonomic identification, elements represented, specimen count, modifications and pathologies, anatomical features of age and sex, measurements, taphonomy etc.). The analytical part is deriving from secondary data (body dimensions, slaughtering profiles, sex ratios, relative frequencies of taxa or skeletal frequency etc.). Primary and secondary data form the basis for interpretations, which focus on the human subsistence strategies, domestication of animals, spacial and temporal aspects of the animal resources etc.

Remains of an European pond turtle (Emys orbicularis) from an early medieval site in Mělník, Nůšařská Street. Photo: L. Kovačíková

Study of archaeozoology at the University of South Bohemia:

• Archaeozoology (KZO/163) – Faculty of Science (Department of zoology, master´s degree)
• Archaeozoology for archaeologists (UAR AZA) – Faculty of Philosophy (Institute of archeology, master´s degree)
• Introduction to environmental archaeology II (UAR/RUE2) – Faculty of Philosophy (Institute of archeology, bachelor degree)

The metatarsal bone of an adult horse (Equus caballus), which is shaped like a skate. Found in Prague, V Tůních 6. Photo: L. Kovačiková

An incomplete skeleton of an adult dog (Canis familiaris) discovered during archaeological research in Staré Badry. Photo: L. Kovačíková

Laboratory of Archaeobotany and Palaeoecology

Analysis of starch grains is a suitable but rather still less common archaeobotany technique in archaeological research. However, starch analysis was employed in archaeological research in last three decades. Starch grains belong into group of plant microremains along with phytolithes, pollen, spores and other “non-pollen” objects. Examination of these plant residues elucidates the changes in the environment, both natural and anthropogenic. Starch occurs as insoluble, semi-crystalline granules in plant tissues as objects with stored energy, which occurs in specific parts of plants such as seeds, roots, tubers (storage organs) and transitory starch. Analysis of starch grains is connected with investigation of plant use and plant processing in past and also composition of herbaceous component of human diet. This technique is also suitable for research in use and function of artefacts, in issue of plant domestication and vegetation history. Damaged starch grains could hinder the use of this particular technique. Results of starch analysis are suitable to complement the result gained through the application of other techniques like palynology, phytolith analysis or plant macroremains

Starch grains from archaeological artifacts. Author: J. Kovárník

Starch is a reserve polysaccharide in majority of autotrophic plants. The exception is presented by families Asteraceae, which store inuline as reserve polysaccharide. Starch is a ready source of glucose for plants, suitable for long storage. It is a composition of two homopolysaccharides (amylose and amylopectine).

Starch is synthesised in green parts of the plant in chloroplasts. There are created small starch grains about 1 µm in diameter, which are called temporary or transitory. These are further used or transported. Starch is further stored in special organelles – amyloplasts. Major quantity of starch is stored in reserve organs in specialized cells of seeds, roots and tubers. Starch is stored in amyloplasts in form of starch grains, which are species-specific and differ in shape, size and polysaccharide ratio. These characteristics of starch grains are for the most part given genetically, but are also influenced by external.

Analysis procedure

Starch can be identified using polarized light optical microscopy where the starch grain has a specific optical expression (extinction cross). Two microscopy workstations are used at LAPE for this purpose. Nikon Eclipse optical microscope and Leica MD 2500 optical microscope. Both workplaces are equipped with a digital camera for recording and a computer with control and analytical software. For accurate morphological analysis of starch grains, it is necessary to use comparative collection. Also can be used the statistical procedure of starch identification of archaeological samples.

Laboratory of Archaeobotany and Palaeoecology

Phytoliths are microscopic particles that form in leaves, stems, roots, flowers or fruits of plants. Most often, these are incrustations formed outside or inside the cells by the accumulation of silica (so-called silicate phytoliths), calcium oxalate, or carbonates. Specific types of cells or their parts or entire sets of cells (for example epidermis) can be encrusted, either their interiors, cell walls or both at the same time. Different taxonomic groups of plants differ in the method of deposition and shape of phytoliths. In many families, specific types of phytoliths were found allowing their determination. Identification at a lower level (genus) is also becoming more frequent, a number of taxa can even be identified down to the species level based on characteristic phytoliths.

After decomposition or burning of plant material, phytoliths (mainly silicate) remain in practically unchanged form and persist for a long time in soil, sediments and other media as a record of the existence of their parent plants.

Possibilities of using phytolith analysis

The potential of phytolith analysis Greater experience with the phytolith taxonomy of present-day plants enables researchers to detect some plant taxa in archaeological sediments based on silica microfossils. The most studied phytolith assemblages come from Central and South America (Piperno 1998a, 1998b; Piperno et Becker 1996; Piperno et al 2000; Piperno et al 2001), North America (McClaran 2000, Fearn 1998, Fredlund et Tieszen 1997, Bozarth 1992, Brown 1984), tropical Africa (Mercader et al 2000, Runge 1999, Barboni et al 1999), New Zealand (Carter 2000, Horrocks et al 2000), the Near East (Rosen 1992), and South-East Asia (Kealhofer et al 1999, Kealhofer et Penny 1998, Zhao et al 1998). Phytoliths are invaluable in archaeology for the detection of cereals (the grass family is an abundant phytolith producer) and other subsistence plants, eg. maize and squash in America (Pearsall 1978, Piperno 1984, Piperno et al 2000, Piperno et Flannery 2001), rice in Asia (Jiang 1995, Whang et al 1998, Zhao et al 1998, Huang et Zhang 2000), and cereals of the Old World (Rosen 1992, Ball et al 1999, Ball et al 1996, Kaplan et al 1992). Though phytolith analysis has an enormous potential, identification using phytoliths is complex and difficult to apply at refined levels of taxonomy.

Phytoliths (like pollen) are used as guide fossils reflecting changes in conditions over time; they indicate ancient dietary and cultural practices; they serve as forensic tools of criminology and can indicate different types of depositional environments (e.g. marine versus terrestrial sediments). Unlike pollen, they are not only preserved in an anaerobic acid environment (typically in bogs), but also in most less extreme conditions, which is widely used. In general, phytolith analysis has much in common with palynology. In the last three decades, phytolith analysis has been the domain of Anglophone countries: primarily the USA, then New Zealand and Great Britain.

Taxonomy of Phytoliths

The occurrence of silicate phytoliths in different taxonomic groups was summarized by Piperno (1988). The best known and most important families with consistent accumulation of phytoliths so far demonstrated are Poaceae and Cyperaceae. The occurrence of calcium oxalate phytoliths is reported in many groups (Arnott 1976, Franceschi et Horner 1980), and their distribution and morphology are traditionally studied in systematic botany. They are consistently produced by, for example, Cactaceae, the morphological diversity of their oxalate phytoliths allows determination into genera and, in the case of prickly pears, into species (Jones et Bryant 1992). Phytoliths formed by calcium carbonate are formed, for example, in the families Urticaceae, Moraceae, Acanthaceae, Cannabinaceae.

Calcareous phytoliths have been studied in less detail than silicate phytoliths from a palaeoecological and archaeobotanical point of view, although they are formed quite often in plants. This is because the frequency of their findings in paleo sediments is usually very low due to unfavorable conditions for preservation and unsuitable conditions for carbonates during the separation of phytoliths from samples (many separation techniques include rinsing in an acidic environment). In general, the systematics of phytoliths is highly heterogeneous and there are several approaches to their classification, which individual authors or working groups create to suit the intended application of the data. A description of the long-term used and updated classification system is given, for example, by Pearsall et Dinan (1992), Piperno (1988), a special classification of dicotyledonous phytoliths is given by Bozarth (1992), Poaceae see Mulholland et Rapp (1992, 1989), Twiss (1992), Twiss et al. (1969).

Phytolith, Poaceae.

Phytolith analysis at LAPE

Due to the fact that in the Czech Republic there is still no workplace dealing with the study of phytoliths in more detail, the LAPE collective is interested in the application of this method in our conditions. Specifically, we are counting on the initial use of the method as part of complex archaeological and archaeobotanical research currently being carried out on Czech archaeological sites from the agricultural prehistory and the Middle Ages. The expected benefit of phytolith analysis lies mainly in the possibility of detecting the practices of the time when handling plant material and reconstructing the type of vegetation cover in the vicinity of the studied settlements. A frequent type of object investigated here is, for example, a granary, i.e. the destroyed remains of a silo, the filling of which contains deposits from the current or immediately following period of the existence of the settlement. We assume that in such objects we will find a statistically significant amount of phytoliths, which would broadly show the composition of the plant material that was handled on the settlement. In addition to the study of sunken objects, we will use cultural layers - the so-called life horizons - which are large-scale deposits created in the residential areas of agricultural settlements of prehistoric times and the early Middle Ages. The samples collected by the network method in the vicinity of the Neolithic longhouses will help in solving the questions of microdistribution of various manipulations with plant material. Another variant will be sampling directly from Neolithic (or younger) grain mills, where phytoliths of cultivated cereals are preserved in high concentrations and in a determinable state.