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Antunes Nicolas 1 , William Banks 1 , Francesco D’Errico 1

Evaluating Viking eco-cultural niche variability between the Medieval Climate Optimum and the Little Ice Age. 1 Univ. Bordeaux, PACEA, UMR 5199, F-33400 Talence, France. Antunes Nicolas 1 , William Banks 1 , Francesco D’Errico 1.

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Antunes Nicolas 1 , William Banks 1 , Francesco D’Errico 1

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  1. Evaluating Viking eco-cultural niche variability between the Medieval Climate Optimum and the Little Ice Age 1Univ. Bordeaux, PACEA, UMR 5199, F-33400 Talence, France. Antunes Nicolas 1, William Banks1, Francesco D’Errico1 DEBATING SPATIAL ARCHAEOLOGYInternational Workshop on Landscape and Spatial Analysis in ArchaeologySantander, June 8th - 9th, 2012

  2. EcologicalNiche(Hutchinson 1957) : a region in a multi-dimensional space of environmental factors that allow species survival (n-dimensional = hypervolume). => Predictive Algorithms

  3. Predictive Algorithms GARP: Genetic Algorithm Rule-set Prediction (Stockwell and Petersr, 1999) Maxent :Maximum Entropy (Phillips et al., 2004, 2006)

  4. Obtaining a niche prediction

  5. Obtaining a niche prediction • 1 – Observed presence – geographic coords. • - Presence / absence or pseudo-absence • Presence only

  6. Obtaining a niche prediction • 1 – Observed presence – geographic coords. • - Presence / absence or pseudo-absence • Presence only

  7. Obtaining a niche prediction • 1 – Observed presence – geographic coords. • - Presence / absence or pseudo-absence • Presence only 2 – Environmental layers

  8. Obtaining a niche prediction • 1 – Observed presence – geographic coords. • - Presence / absence or pseudo-absence • Presence only 2 – Environmental layers 3 – Algorithm Run => Hypervolume calculation => Applied to each pixel.

  9. Obtaining a niche prediction • 1 – Observed presence – geographic coords. • - Presence / absence or pseudo-absence • Presence only 2 – Environmental layers 3 – Algorithm Run => Hypervolume calculation => Applied to each pixel. Ecological Niche Estimation

  10. Eco-cultural Niche Modelling ( ECNM) • Replacement of Species by Culture Culture locations Predictive Algorithm Ecocultural Niche Environnemental layers

  11. Norse Settlement

  12. Collapse hypothesis

  13. Collapse hypothesis • Isolated

  14. Collapse hypothesis • Iron • Timber • Fresh water • Hay • Isolated • Wind & SummerDrought

  15. Collapse hypothesis • Iron • Timber • Fresh water • Hay • Isolated • Wind & SummerDrought • Disease & Famine

  16. Collapse hypothesis • Iron • Timber • Fresh water • Hay • Isolated • Wind & SummerDrought • Disease & Famine • Farming Impact

  17. Collapse hypothesis • Iron • Timber • Fresh water • Hay • Isolated • Wind & SummerDrought • Disease & Famine • Farming Impact • Conflictwithindigenous • Piracy

  18. Collapse hypothesis • Iron • Timber • Fresh water • Hay • Isolated • Wind & SummerDrought • Disease & Famine • Farming Impact • Conflictwithindigenous • Piracy Little Ice Age

  19. first to disappear (Abandoned Sites before 1350 AD) Sites occupied during MCO and the LIA

  20. MCO Settlement LIA Settlement Settlement location

  21. Example: January, 801 DCE, Global simulation (Jungclaus 2010) Surface Solar Radiation Surface Temperature Mean Barometric Pressure Precipitation

  22. Spatial Focus : Northern Regions Time Focus 1: IX / X Centuries Time Focus 2: XV /XVI Centuries Mean by year Mean by January Monthes Mean by April Monthes Mean by July Monthes Mean by October Monthes Mean by year Mean by January Monthes Mean by April Monthes Mean by July Monthes Mean by October Monthes 20 Climatic Variables 20 Climatic Variables

  23. Interpolation of each 2x20 layers Var LD Var HD =>future = Statistical DownScaling

  24. EnvironementalLayers DEM 20 Climatic Variables future experiments => more topographic variables

  25. Maxent GARP MCO MCO LIA LIA Presenceprobability

  26. Quantifying the environmental parameters that define the predicted niche presence presence presence Environmental Layers (x21) ECNM Prediction => Principal Component Analysis (PCA)

  27. MCO

  28. Densities of predicted area as a function of climatic variables October Precipitation MCO Settlement LIA Settlement July Solar Radiation January Barometric Pressure October Temperature

  29. Densities of predicted area as a function of climatic variables October Precipitation MCO Settlement LIA Settlement July Solar Radiation Left offset of Niche January Mean Sea Level Pressure at the Surface October Temperature

  30. Perspectives • Add additional variables • Apply Downscaling method • Compare Niche Breadth • Evaluate possible niche shift

  31. Gracias por su atención.

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