Tuesday, 13 January 2015

Goats and reeds in the Neolithic

Bulliform cells in modern Zea mays tissue (source: Visuals Unlimited, Inc)
Fellow animal dung enthusiast Sarah Elliot at the University of Bournemouth shared this fab little article describing the use of 'Eco goats' to manage invasive plants in the US. It is especially interesting that they note the use of goats as a pesticide-free way to manage Phragmites reeds. These reeds have distinctive phytoliths which archaeologists call 'keystone' bulliforms, which are relatively large single cell phytoliths that are named as they are said to resemble a Roman keystone arch in cross section.  In transverse section they look a bit sausage shaped, and within a plant these cells are 'stacked' next to each other as part of the upper epidermis (the plant 'skin'), and are related to water storage. If you're a botanist you might also call these motor cells, because during times of water stress, they shrink and cause leaves to fold or curl up. Phragmites phytoliths are seen frequently in ash deposits at Neolithic sites in the Near East, including Boncuklu and Catalhoyuk, and are also found contained within ovicaprid dung pellets, giving a direct indicator that these plants were consumed by the animals. Identification of plant types within preserved animal dung can be used to understand where animals may have been grazing within a landscape, or help understand past climates, environments and water availability. The modern Eco Goats can munch their way through half an acre of dense vegetation in a period of four days. Sheep/goats make up the majority of animal bones at Catalhoyuk, although estimating herd sizes is difficult. Nevertheless it is likely that they played an important role in managing the local reed beds!

Phragmites bulliform cells embedded within ovicaprid dung pellet from Catalhoyuk

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