The Economic System: Data and Hypotheses

The general properties of the socio-economic system of the wetland sites have been described by various authors in relative consistency, e.g. Menotti (2004), Jacomet (2009), Gross et al.

(1990) and can thus be described as follows. The inhabitants of the wetland settlements lived on a mixed diet comprising of products from crop and livestock husbandry, hunting, gathering and fishing. The relative importance of these elements varied due to external and internal factors (e.g. Schibler and Jacomet 2010; Schibler 2006) but it is generally agreed on that cereals provided a large proportion of the calorie demand. Hypotheses on crop husbandry vary, but it is highly probable that the plough was not used during the 5th and the first half of the 4th millennium BC (Ebersbach 2002). People built elevated houses in close proximity to or directly in shallow lake areas or in peat bog. The average lifetime of the houses was only several years (Ebersbach 2010), and accordingly, the occupation time of many of the sites was short. Interpretation of published data by the individual authors with respect to the internal functioning of the subsystems, however, is not always consistent (e.g. Ehrmann et al. 2009; Bogaard 2002, 2004).

This is especially true for the crop husbandry system. The major hypotheses on crop husbandry systems are:

(1) Shifting Cultivation (SC). The main arguments for this hypothesis on crop husbandry and land-use is evidence for frequent large-scale fires and for an increase in scrubland vegetation dominated by hazel at the beginning of the 4th Millennium BC (Rosch et al. 2002; Rosch 2014), which is correlated with settlement activity (Lechterbeck et al. 2014). Several authors interpret these phenomena as a result of a land-use system that is based on ash fertilization of the crop fields, e.g. (Ehrmann et al. 2009; Schier 2009).

In this system, high nutrient availability due to a burning procedure allows for high yields, while the high demand for wood for the burning and very intense weed growth in the second year after the fire necessitate an annual shifting of the fields. Based on experimental reconstruction of this system, I assume annually varying yields with a long-term average of 2700 kg/ha (100 % dry matter) for SC on soils of average quality (Ehrmann et al. 2009, p. 67). Annual variation of the yield due to weather conditions is accounted for in all simulated husbandry systems as described below. An important objection to this scenario is the evidence that backs the following hypothesis (IGC).

(2) Intensive Garden Cultivation (IGC). The weed content of well-preserved crop stores have been analyzed (e.g. Maier 1999; Bogaard 2004; Jacomet 2006) using, among others, the FIBS-approach (Charles et al. 1997). The ecological properties of the crop weed plants are interpreted as evidence for a crop husbandry regime, which is in contrast to SC—based on permanent fields that are cultivated for more than just a couple of years (Bogaard 2004, p. 41 ff.). The analysis of isotope relations of the cereal grains justify the assumption of the use of animal dung for manuring of the fields, so that a small-scale, permanent and highly intensive cultivation is reconstructed (Bogaard 2012; Bogaard et al. 2013). Based on data of the Rothamsted Research Station on long-term cultivation of wheat with manure application, I assume an average yield of 2000 kg/ha (100 % dry matter; Poulton 2006), also with annual variation due to weather events. IGC requires a large number of livestock for producing enough dung; however, archaeological reconstructions of the minimal number of animal individuals (MNI) in the lake-shore sites seldom meet these numbers (Ebersbach 2007; Ebersbach 2013). Furthermore, the hypothesis does not explain the peaks of charcoal and secondary forest found in the pollen stratigraphies.

(3) Non-Intensive Cultivation (NIC).

This scenario is basically the same as IGC, but with the difference that no manure is applied and thus, yields are markedly lower and soil nutrient depletion may occur after some time. I assume an average yield of 800 kg/ha (100 % dry matter), also based on the Rothamsted dataset (Poulton 2006).

(4) Integrated Forest Horticulture (IFH). During the formulation of the model, it has become obvious that neither of the land-use models published so far (SC, NIC and IGC) is capable of integrating all data with confidence. Therefore, an alternative scenario (IFH) has been formulated in the course of the modelling procedure, which combines elements of the other scenarios, but is in better agreement with the published archaeological and environmental evidence. In this scenario, a large amount of the calorie demand is covered by hazelnuts, the growth of which is promoted anthropogenically. Thus, the peaks of charcoal and secondary forest as documented by palynology (e.g. Rosch 2014) might result out of the targeted stimulation of hazel growth, not of cereal cultivation. Cereals, in contrast, could make up only a minor portion of the diet. Therefore, only small fields might be sufficient, and intensive cultivation and manuring as described for IGC can be performed with a lower livestock density. Both the observations that led to the formulation of the SC-Hypothesis and the evidence for manure application and small, permanent fields as in IGC are included in consistency.

Further models on economic subsystems include:

(5) Livestock husbandry regimes. The relative importance of livestock, especially cattle, is debated; while cattle bones with signs of butchery are found frequently, the reconstruction of an approximate number of cattle kept per person is difficult and varies spatially and chronologically (Ebersbach 2013). This is important not only with respect to the nutritional significance of livestock, but also in relation to the possible amount of manure available for IGC and IFH (see Bogaard 2012).

As dense forests covered the land—at least at the beginning of the sequence—large areas were presumably needed for forest pasture and pollarding. As the fodder value (i.e. the amount of fodder per area) of secondary forest is much higher than that of old-growth primary forest, a further reason for the charcoal and hazel peaks may be found here.

(6) Forest management strategies. An ubiquitous and mostly well preserved element of the wetland sites are the remains of wooden construction piles. The analyses of their tree-ring patterns yields not only an absolute dating for the felling of the trees, but also information on the structural and compositional features of the forest stands they grew in (Billamboz and Koninger 2008; Bleicher 2009; Billamboz 2014). While coppiced forest or single tree selection dominated in some phases, in others only a few old trees seemed to be available. Likely for the ease of processing, quite young trees with a diameter of 520 cm were preferred in the beginning of the 4th Millennium. As these are not necessarily available in adequate numbers in a primeval forest, a suitable stand certainly constituted a valuable resource. Again, anthropogenically induced secondary forest growth might have been a valid strategy to improve resource availability.

(7) Foraging. Hunting, Gathering and Fishing are documented in most of the sites. The overall importance is difficult to assess for a number of reasons and may have varied largely (e.g. Schibler 2006; Jacomet 2006). Schlichtherle et al. (2010) stated a link between an increase in hunting and low crop harvests due to bad weather for the settlements at Lake Zürich. The importance of fish is not well documented; however, Gross et al. (1990) stated that fish is low in calories and thus, a change in the quantity of fish cached would not necessarily make a large difference. Gathering of wild plants is documented regularly. Among the gathered plants are fruit, berries, herbs and especially nuts. Concerning the latter, it could be demonstrated that generally, they are extremely rich in calories and make an easy-to-store staple food (Holst 2010). While gathering activities are included in some detail within WELASSIMO, hunting and fishing are not treated as a single process but are instead merely represented in a schematic way.

9.4

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Source: Barcelo Juan A., Del Castillo Florencia (eds.). Simulating Prehistoric and Ancient Worlds. Springer,2016. — 410 p.. 2016

The Economic System: Data and Hypotheses

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