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P2 - Anthrosols and Intensity of Human Occupation

PI: Bruno Glaser, Wolfgang Zech | Tamrat Bekele, Sileshi Nemomissa Duguma, Itanna Fisseha

PhD-Students: Betelhem Mekonnen, Tobias Bromm, Bruk Lemma

Overview

Anthrosols is the typical soil type of the Anthropocene and the human environment (Bork 2006). In the Bale Mountains, Anthrosols are mostly confined below rock cliffs providing shelter against the trade winds. Using numeric dating (14C, OSL), Anthrosols are suitable archives to reconstruct the chronology of human occupation. The Intensity of Human Occupation in space and time will be reconstructed by means of molecular markers with special reference to pyrogenic carbon, using benzenepolycarboxylic acids as a fire tracer (Glaser et al. 1998), stanols and bile acids to detect human and animal excrements, and alkaline CuO oxidation of lignin to differentiate grasses from woody plants and cutin/suberin analysis (Otto and Simpson 2007).

Achievements

  1. Sanetti Plateau sites without Erica are free of charcoal and have low black carbon contents. Therefore, they are most likely not burnt. Erica occurs preferentially at sites with boulders (Fig. 1).
  2. Erica vegetation at the Sanetti Plateau could be successfully identified using the phenol pattern (Fig. 2).
  3. Unambiguous proof of human use of a Middle Stone Age residential site (Fig. 4).

Objectives

  1. Evaluation of the temperature regime, nutrient and water supply of Erica at the Sanetti Plateau to exclude that mal-nutrition and water stress besides climatic factors (especially temperature) and human impact contribute to the disappearance of Erica on the plateau.
  2.  Identification of unambiguous molecular marker for Erica based on the screening further phenols, tannins, terpenoids and environmental DNA.
  3. Reconstruction of the temporal and spatial distribution of the Erica vegetation at the Sanetti Plateau based on biogeochemical analyses of soils and sediments in depressions and lakes.
  4. Investigation of Anthrosols older than 10 ka found under rock shelters in parts of the Sanetti Plateau not studied up to now.
  5. Spatial up-scaling of human occupation at the Sanetti Plateau.
Erica_at_boulders
Photo: FOR 2358
rockshelter_p2.jpg
Photo: FOR 2358

 

Figure 1 : Erica vegetation at sites with boulders on the Sanetti Plateau, Ethiopia 

Figure 2: Rockshelter site

Publications

Gil-Romera G, Adolf C, Benito B, Johansson M, Bittner L, Fekadu M, Glaser B, Mekonnen B, Grady D, Lamb H, Lemma B, Rensen D, Zech M, Zech W, Miehe G (2019) Long-term fire resilience of the Ericaceous Belt, Bale Mountains, Ethiopia. Biology Letters 15.

Mekonnen B, Glaser B, Zech M, Addis A, Nemomissa S, Bekele T, Zech W (2018) Late Glacial and Holocene landscape history of the Sanetti Plateau, Bale Mountains (Ethiopia) as deduced from biogeochemical proxies of lacustrine sediments. Poster presented at the conference of the German Association of Stable Isotope Research, Munich.

Lemma B, Grehl C, Zech M, Mekonnen B, Zech W, Nemomissa S, Bekele T & Glaser B (2019): Phenolic Compounds as Unambiguous Chemical Markers for the Identification of Keystone Plant Species in the Bale Mountains, Ethiopia. Plants 8 (7), 1-15.

Ossendorf G, Groos AR, Bromm T, Tekelemariam MG, Glaser B, Lesur J, Schmidt J, Akçar N, Bekele T, Beldados A, Demissew S, Kahsay TH, Nash BP, Nauss T, Negash A, Nemomissa S, Veit H, Vogelsang R, Woldu Z, Zech W, Opgenoorth L & Miehe G (2019) Middle Stone Age foragers resided in high elevations of the glaciated Bale Mountains, Ethiopia, Science 365 (2019), 583-587.