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Table 1: The variables and datasets used to explore spatial structure in extant African landscapes, and brief details of how each dataset is displayed
Dataset Variable (units) Display parameters Source(s) and references
Climate Annual mean temperature (°C) On a spectrum from blue (low) to red (high), using a minimum-maximum stretch. All datasets from the WorldClim database of 30 arc-second resolution global maps (Hijmans et al. 2005).
These data are available from http://www.worldclim.org/current
Annual mean rainfall values (mm) From blue (low) to green (high), using a minimum-maximum stretch.
Rainfall seasonality (the coefficient of variation on annual rainfall; in arbitrary units from 0-300) From blue (low) to red (high) using a minimum-maximum stretch.
Temperature seasonality (the standard deviation of annual temperature x 100; in arbitrary units from 0-225,000) From blue (low) to red (high) using a minimum-maximum stretch.
Vegetation/ecology Vegetation structure map (classifying into 'open', 'semi-open', 'closed', 'aquatic', 'anthropogenic' and 'arid/semi-arid' categories) Different colours indicate different vegetation types. Closed vegetation = dark green; semi-open = light green; open = yellow; aquatic = blue; anthropogenic = grey and arid/semi-arid = beige. This dataset comes from the physiognomic layer of the Useful Tree Species for Africa tool, based on White (1983)'s Vegetation Map of Africa at 1:5,000,000 scale.
The data are available from http://www.worldagroforestrycentre.org/our_products/databases/useful-tree-species-africa
WWF ecoregions map (an 'ecoregion' is a characteristic, geographically and ecologically defined assemblage of communities and species). This map combines data on vegetation, species richness and endemism Different colours indicate different ecoregions. This layer is drawn from the WWF 'Terrestrial Ecoregions of the World' data (Olson et al. 2001).
The data are available from http://www.worldwildlife.org/publications/terrestrial-ecoregions-of-the-world
Landscape (terrain and spatial patterning) Altitude (metres above sea level) From blue (low) to red (high), using a standard deviations x2 stretch. These data come from the SRTM 90m Digital Elevation Database v4.1 (Jarvis et al. 2008). Resampled 250m resolution data were used throughout.
Roughness maps were derived from topographic ones as described in the method section.
SRTM4.1 data is available from http://www.cgiar-csi.org/data/srtm-90m-digital-elevation-database-v4-1
Terrain roughness – a measure of the variability in slope orientations (arbitrary units from 0 to ~8) From blue (low) to red (high) using a standard deviations x2 stretch.
Surficial geology Different colours indicate different geological units. This layer draws on the 'Surficial geology of Africa' dataset (USGS 2000).
The data are available from http://certmapper.cr.usgs.gov/data/we/ofr97470a/spatial/export/geo7_2age.zip
Surficial soil types Different colours indicate different soil types. These maps were used only at larger (continental and regional) scales because they were of relatively lower resolution. This layer comes from the Harmonized World Soil Database (FAO/IIASA/ISS-CAS/JRC 2009).
The data are available from http://webarchive.iiasa.ac.at/Research/LUC/External-World-soil-database/HTML/HWSD_Data.html?sb=4

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