Human impact
Of special interest are the first attempts of prehistoric farming. The change from hunter-gatherers to organized farming communities is considered a key process in the history of humankind. This change would have been a long process of progress and setbacks. The first occurrence and location of agricultural practice in northwest Europe is disputed. Concluding whether an archeological site contains evidence for agriculture is rather subjective. Findings of single pollen grains of the Cerealia-type have sometimes been used to reconstruct an entire Mesolithic agricultural society, an approach that was strongly criticized by Behre (2007). Herbaceous species linked to human occupation or disturbance (light; open soils) are indicated as apophytes (sensu Behre 1981). The natural habitat of apophytic species was in places disturbed by wind, fire or other natural causes (Wittig 2004). With an increasing amount of human settlements there were more disturbances, which was advantageous for the apophytes as they became associated with disturbance related to human settlements.
The palynological data from site Schokkerhaven-E170 show some close links between the occurrence of pollen of Cerealia-type and apophytes. This link could not be established in Zone Ia (Late Atlantic period). Both Asteraceae (both tubuliflorae and liguliflorae) and Caryophyllaceae occur in this zone but no cereals were found. In Zone Ib (radiocarbon dated: ca. 5000 BP; corresponding to ca. 3950 to 3700 cal BC) relatively high values of Cerealia, Rumex acetosella-type, Brassicaceae, Melampyrum, Jasione-type and Caryophyllaceae occur. Single finds of Succisa, Polygonum persicaria and Fallopia are also present in Zone Ib, while low amounts of pollen of Urtica dioica occur at the transition from Zones Ib to Zone II. Some apophytes follow the Cerealia-type curve more closely than others. The recorded plant taxa indicate the presence of various plant communities, Urtica points to nitrogen rich areas. Other taxa (Fallopia, Polygonum persicaria, Asteraceae, Rumex acetosella) are typical for arable fields while Succisa and Plantago lanceolata indicate meadows. The occurrence of Cerealia-type pollen alone cannot be taken as proof for agriculture (Behre 2007), but the presence of apophytes supports this interpretation.
The record of pollen of Cerealia at site Schokkerhaven-E170 is supported by a variety of other indicators for agriculture and apophytes, charcoal particles and the records of coprophilous fungi provide further support for human impact. The spores may have developed on human feces, but dung of wild and/or domesticated animals may have been the most important substrate for these fungi (Van Geel et al. 2003). With regard to the fungal evidence for grazing, it is not possible to distinguish between domesticated and wild animals.
In zones I and II the combined presence of cereals, apophytic species, coprophilous fungi and charcoal clearly indicate the presence of humans and agricultural activity. The three radiocarbon dates place the recorded human impact in the late-Swifterbant culture. The dates complement the radiocarbon dates obtained from charred hazelnut shells, charcoal and charred food remains from a pottery sherd (Lanting & Van der Plicht 2002) sampled at the site in the late 1980s by J.W.H. Hogestijn (see above). The Swifterbant culture in this region is succeeded by the Funnel-beaker culture. Possible indications for later human presence in the diagram are the peak of Cercophora spores in zone IVa and the small peak of Cerealia-type in zone V. Although the indications are not as strong, both could suggest local Funnel Beaker culture agricultural activity, corresponding to the radiocarbon dates obtained on some wooden posts (Lanting & Van der Plicht 2002), also sampled by Hogestijn.