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• Environmental Factors in the Chronology of Human Evolution and Dispersal (EFCHED)

Data copyright © Prof Paul Valdes unless otherwise stated

This work is licensed under the ADS Terms of Use and Access.

Primary contact

Prof Paul Valdes
School of Geographical Sciences
University of Bristol
43 Woodland Road
Bristol
BS8 1UU
UK

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Resource identifiers

• ADS Collection: 738
• DOI:https://doi.org/10.5284/1000212
• How to cite using this DOI

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Project Aims

The project aim was to develop process-based computer simulations of the dispersal of Homo erectus out of Africa. This involved developing realistic constraints on the patterns of vegetation and the effects of changes in global sea level. It was assumed that this migration out of Africa could be investigated through the paradigm of a single migration event, starting around 2 millions of years ago and arriving in Dmanisi around 1.8 millions of years ago.

Archive description

The data archived here consists of the vegetation patterns used in constructing the simulations and the patterns of climate variability used to constrain the variations in sea level and vegetation change. From these data it is possible to reproduce the simulation results. Simulation results are available from:

J.K. Hughes, A. Haywood, S.J. Mithen, B.W. Sellwood, P.J. Valdes (In Press) 'Investigating Early Hominin Dispersal Patterns: developing a framework for climate data integration'. Journal Of Human Evolution.

The land distribution and orography used were from the ICE-4G data set, and can be obtained through the USGS from: http://geo-nsdi.er.usgs.gov/metadata/other/pages-93-015/metadata.faq.html

• File 1 - Climate_variability.csv - contains three alternative climate variability records implemented (corresponding to a plio-pleistocene vegetation transitions at 2.5, 1.8 and 1.0 Mya). This record is based on benthic foram data from the Delphi project (http://www.esc.cam.ac.uk/delphi/).
• File 2 - Climate_var_modern.csv - contains the climate variability data set used in modern Homo sapiens simulations, derived from the Vostok ice core (http://cdiac.ornl.gov/ftp/trends/co2/vostok.icecore.co2).
• File 3 - Vegetation.txt - contains the vegetation patterns used in Stepping Out. To read in the data from this file use the following Fortran code structure:
  
  OPEN (14,file='Vegetation.txt')
DO I=1,12
DO X=1,360
DO Y=1,180
READ(14,*) Veg(X,Y,I)
ENDDO
ENDDO
ENDDO
CLOSE(14)

The index level 'I' to be used at a particular time step is then specified by the Climate_variability.csv value. These vegetation distributions were derived from climate model (GCM) simulations of glacial to interglacial climate variability (1-11, 1=glacial) and of the mid-pliocene warm period (12). It is strongly recommended that anyone intending to make use of these vegetation data contact Professor Valdes of Bristol University (p.j.valdes@bristol.ac.uk) to discuss the nature of these vegetation patterns and the process-based modelling that produced them. The science behind the climate model simulations are, at present, rapidly developing and it is expected that the vegetation patterns will be superceded in the near future. Vegetation codes correspond to 1) tropical forest, 2) warm-temperate forest, 3) temperate forest, 4) boreal forest, 5) savannah and dry woodland, 6) grassland and dry shrubland, 7) desert, 8) tundra, 9) land ice and 10) ocean.

In the dispersal modelling the sequence of events was:

• Initialisation
• Start of main loop
• Colonisation
• Extinction
• Preliminary output
• End of main loop
• Final output

Files