Biodiversity Hotspot Enabled Neanderthals To Survive Longer In South East Of Spain

The international team jointly led by Spanish researchers has reconstructed the landscape near Gorham's Cave in Gibraltar, by means of paleobotanical data (plant fossil records) located in the geological deposits investigated between 1997 and 2004. The study, which is published in the Quaternary Science Reviews, also re-examines previous findings relating to the glacial refugia for trees during the ice age in the Iberian Peninsula.

"The reconstructed landscape shows a wide diversity of plant formations in the extreme south of the Iberian peninsula from 32,000 to 10,000 years ago," José S. Carrión explains. He is the principal author and researcher from the University of Murcia. The most significant finding amongst the steppe landscape, pine trees, holm oaks, oak trees, deciduous trees, and others, is the presence of "plant elements indicative of a warm environment," states Carrión.

This research shows that the plant diversity discovered in the cave is "unique" in the context of the ice age that affected the entire European continent. The area of Gibraltar and the adjacent mountain ranges made up a "large refugium for plant and animal biodiversity during the coldest periods of the Pleistocene Ice Age" and made it possible for the Neanderthals to survive for 10,000 years longer than the rest of Europe.

The researchers suggest that the caves situated between the coasts of Malaga and Gibraltar "represent an area that favours the survival of a large diversity of environments." The analysis of the refugia in the Peninsula shows that there were many other places where trees provided a refugium, "but this never compared to the diversity of species in the south, south west and south east," emphasizes Carrión.

In search of comfort

In Gibraltar, the Neanderthals could have had access to more than 140 caves, which provided them with a wealth of resources. The research mentions a corridor along the coasts of the south east of Spain that the Neanderthals possibly used in order to avoid the steep terrain found in the interior mountain ranges which had inhospitable climatic conditions during this Quaternary Period.

The existence of this biodiversity hotspot with a supply of plant and animal foodstuffs available "would explain the extraordinary endurance of the Neanderthals in the south west of Europe," emphasizes the researcher. On the other hand, the Neanderthals in the south of Europe had become adapted to surroundings that had semi forest vegetation, as well as fishing resources off the coast, which encouraged their survival.

The inhabitants of Gorham's Cave were omnivorous and ate land mammals (mountain goats, rabbits, quails, duck and pigeon) and marine foods (monk seals, dolphin, fish and mussels). They also ate plants and dried fruits such as those found in the cave that date from 40,000 years ago. They adapted easily to their environment and took advantage of what this provided.

The paleobotanical data collected by the researchers from the Museum of Gibraltar, the Catalonian Institute of Human Paleoecology and Social Evolution, the Laboratory of Archaeobotany (CSIC), the University of Wales (United Kingdom), the University of York (United Kingdom), Pyrenean Institute of Ecology (CSIS) and the University of Murcia, were obtained by studying carbon remains and fossilised pollen grains found in the packed sediment in the cave and in coprolites (fossilised faeces of animals) from hyenas and canids (wolves, jackals, foxes, etc).