Vegetation context and climatic limits of the Early Pleistocene hominin dispersal in Europe

Abstract

a b s t r a c tThe vegetation and the climatic context in which the first hominins entered and dispersed in Europe during the Early Pleistocene are reconstructed, using literature review and a new climatic simulation. Both in situ fauna and in situ pollen at the twelve early hominin sites under consideration indicate the occurrence of open landscapes: grasslands or forested steppes. The presence of ancient hominins (Homo of the erectus group) in Europe is only possible at the transition from glacial to interglacial periods, the full glacial being too cold for them and the transition interglacial to glacial too forested. Glacial-interglacial cycles forced by obliquity showed paralleled vegetation successions, which repeated c. 42 times during the course of the Early Pleistocene (2.58-0.78 Ma), providing 42 narrow windows of opportunity for hominins to disperse into Europe.The climatic conditions of this Early Pleistocene vegetation at glacial-interglacial transitions are compared with a climatic simulation for 9 ka ago without ice sheet, as this time period is so far the best analogue available. The climate at the beginning of the present interglacial displayed a stronger seasonality than now. Forest cover would not have been hampered though, clearly indicating that other factors linked to refugial location and soils leave this period relatively free of forests. Similar situations with an offset between climate and vegetation at the beginning of interglacials repeated themselves throughout the Quaternary and benefitted the early hominins when colonising Europe.The duration of this open phase of vegetation at the glacial-interglacial transition was long enough to allow colonisation from the Levant to the Atlantic.The twelve sites fall within rather narrow ranges of summer precipitation and temperature of the coldest month, suggesting the hominins had only a very low tolerance to climate variability.

Comparative analysis of coatings on granitic substrates from urban and natural settings (NW Spain)

“…present). However, recent studies revealed that only minor climatic oscillations have occurred since 9 ka BP (Leroy et al, 2011). Thus, coatings from O Pindo could have ages younger than this last age.…”

Villafranchian large mammals from the Iberian Peninsula: paleobiogeography, paleoecology and dispersal events

“…1.4-1.2 Ma; Palmqvist et al, 2005;Carbonell et al, 2008;Martínez-Navarro et al, 2010). In the Iberian Peninsula, this time interval was characterized by warm temperatures and no great climatic shifts, with landscapes dominated by open dry grasslands and several wooded areas (Leroy et al, 2011). Several authors suggested that the paleoenvironmental conditions most favorable for the dispersal of hominins across Europe would correspond to open landscapes, similar to the African environments where early Homo had evolved.…”

Accounting for hominins’ fast exit from Africa (“The Out of Africa Event 1”) due to widespread wildfires, accidently and inevitably ignited by them, c.a. 1.8 – 1.6 mya

“…This signifies that small, controlled, campfires were most probably used for warmth in combination with cave-dwelling while the retainment and the growth of more body hair over time, also figure into that equation. This is even whenever any journeys up to the far north experienced a limited timewindow of interglacial conditions (Leroy et al, 2011) which still would have seen low temperatures, although not as low as when it was under full glacial conditions. Yet, Dennell (2012) claims that hominins such as H. erectus of Dmanisi, did not have to endure cold temperatures because he assumed that they only settled into their mid-latitude environment (at latitude 41° N) during the summer months followed by their evacuation from Dmanisi when cold temperatures arrived.…”