Wednesday, July 24, 2013

Day 17: Paleoethnobotany and Starbucks Coffee

Day 17- Paleoethnobotany, People and Plants in the Past

Talk about your alliteration! Get it? Well, I enjoyed it. Yes, Paleoethnobotany is the study of ancient peoples through the study of the plants remains, which have survived in archaeological contexts. Paleoethnobotany is an archaeological sub-field of study which uses the identification of plant remains, in combination with the ecological and cultural information we have thanks to modern plants, are able to study the use of wild plants, origins of agriculture and domestication, and the co-evolutionary nature of the human-plant interactions across time.

For this lecture, Dr. Kandace Hollenbach from the University of Tennessee at Knoxville was kind enough to come to Monticello to shine the light of paleoethnobotany on us field school students. Dr. Hollenbach's studies focus on the prehistoric foodways among hunting-gathering and agricultural peoples of the southeastern US, gender and identity roles, and the use and meaning of landscape among those hunting-gathering peoples as well.

Dr. Hollenbach's lecture focused on the rituals, use, and ancient peoples' thoughts of plants, her bottom line to us was, "people effect plants and in return the plants effect the people as well." People use plants for a multitude of reasons, they procure, process, prepare, consume, discard them, and frequently they are not preserved. The fact that they are not preserved leaves no evidence for paleobotanists and archaeologists. In terms of plant (either in the form of pollen or phytoliths) preservation, dry conditions are best, and wet conditions are destructive. Wet conditions can result in water logged, anaerobic conditions, meaning there is not enough oxygen for microbes to live and destroys the botanical remains completely. Plants can also be carbonized, this occurs when botanical remains become trapped and squeezed between sediments, are turned into carbon as they deteriorate, and since animals and plants get zero energy from carbon, the plant is left alone.

The preservation of micro/macro-botanical remains are then left to procurement. Procurement assumes the food item was gathered, harvested, or purchased.
Procurement = eating = digesting = paleofeces (coprolites)
Harvesting = food processing = eating = coprolites
OR Harvesting = processing = byproduct, then burned for fuel or trash disposal
Harvesting can also lead to the byproduct simply decaying on its own, whether it is simply disposed of, or as spill.

In the field of paleoethnobotany, certain biases are necessary to consider when reviewing a sample, these include:

  • byproducts being over-represented relative to the edible portions
  • items not cooked with fire are under-represented 
  • items that burn to ash (e.g. leaves) or unrecognizable mass (potatoes, etc.) are under-represented. 
  • small, fragile items that don't burn well and do not withstand mechanical damage (freeze/thaw and recovery techniques are under-represented
One also cannot go directly from numbers of remains located to the importance of crops in any civilization's lives. Instead, cross-reference your finds (i.e. a high number of corn remains) with the ethnohistorical accounts of crops and diets to enforce the located evidence. However in the reality of the historical record, white European men (early colonial settlers) simply do not write about the native's crops or dietary practices.

The recovery stage of both macro and micro-botanical remains is accomplished a process known as flotation, which can either be mechanized through a "float tank," or by hand. The next step is to analyze the remains under a microscope and identify them. The use of a modern comparative collection can come in handy during this stage and most collections collect and burn modern samples for precise references.

The interpretations of micro and macro-botanical remains focuses in on the subsistence and foodways of ancient peoples, the procurement, processing, storage, preparation/cooking, consumption, and discard practices offer a picture of how people are living on the site. For example, plant domestication can be followed by the changes through time and across location (regional patterns) to the crop. Paleoethnobotanists are finding that people are choosing larger seed sizes as time moves forward as well as a thinning of the seed coat. Wild seeds need their coating in order to survive the winters but domesticated seed are preserved through storage, resulting in the eventually thinning of their coats. Thin coats also sprout first and produce the most seeds for the next season's harvest as well. The importance of the coat lies not only in the agricultural value, aids in the successful identification and separation of wild seeds and domesticated seeds, since coats can be used to differentiate between the two. Plants co-evolve as people interact in their lives and there are changes in both the plants and people. People get tied down to spots with agricultural plots, going from a once continually moving, hunting-gathering society, to a settled, stable one illustrates the mutual domestication plants had on people as well!

Dr. Hollenbach then transitioned into the second portion of her lecture, which surrounded her research involving human behavioral ecology, arguing the costs and rewards of walking to gather or hunt a food source. The central place foraging theory is used to mathematically point out characteristics in people's behaviors, by solving for the return rate of the energy spent to collect the food item, with the energy obtained from the item, in consideration with the time spent to find, collect, or hunt the item. This is achieved through ethnohistorical accounts of the individual peoples, in combination with experimental archaeology, which Dr. Hollenbach admits to sending her grad students on a walking expedition to achieve.

*handling cost outweighs carrying cost
Squirrel = High handling cost (30kg)

  • walking cost (tied to slope and distance of specific landscape)
  • amount of time it takes to actually catch a squirrel
  • minimal gain in energy obtained
  • travel cost doesn't matter as much
Spawning Fish = Low handling cost (30kg)

  • assume the people know their surrounding landscape and know the location and the worth of the river where this resource can be continually found. 
  • travel cost matters
Given this mathematical breakdown of the cost vs. reward of various food sources, Dr. Hollenbach can hypothesis that most campsites of ancient people are made with a low cost food source close in distance. For example, fish are a reliable food source, they can always be found in a nearby river, whereas deer could be anywhere, and would therefore cost more to locate and carry, but if found would outweigh fish in the energy gained category. So it all comes down to how much energy you are willing to spend in the hopes of gaining equal or more energy in return for a specific food source/item.

Back to the micro and macro remains, these can also be used to identify the social and political organization of people, or any socio/politcal shifts which occurred throughout time within that society as well. In today's world think about your own personal reactions when you notice someone walk passed you holding a Starbucks coffee cup rather than a local, fair trade coffee brand/cup, certain social and economic assumptions are made on your end, and a social status signal is put out by the other person (the one holding the coffee cup). Certain aspects of our personal identity can be based on our favorite foods. MIND BLOWING! Think about that the next time you are going to treat yourself to a cup of brew- will you go commercial or local?

I promise to keep catching up on my blog updates- it is such a commitment!

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