FIGURE 1 in Environmental correlates of the European common toad hybrid zone

FIGURE 1 Western Europe with France and adjacent countries in Mercator projection. Colours from green to brown indicate increasing altitudes. The Bufo bufo versus B. spinosus mutual range delineation is based upon molecular genetic data, in which the smooth interrupted line is derived by linear interpolation whereas the more angular line is based upon Dirichlet cells (for details see text). The small bodied common toad B. bufo occurs to the northeast and the large bodied spined toad B. spinosus to the southwest of the mutual range border. Environmental data were gathered for 17 overlapping and adjoining circular windows positioned over the mutual range border. Here shown are window 1 in the northwest of France, window 17 in the northwest of Italy and windows 5, 9 and 13 in between. The two boxed areas are highlighted in fig. 3. The base map was downloaded from MapsLand at https://www.mapsland.com, under a Creative Commons Attribution-ShareAlike 3.0 Licence. The animal drawings are by Bas Blankevoort, Naturalis Biodiversity Center.