The Iberian Peninsula – corridor or cul-de-sac? Mammalian faunal change and possible routes of dispersal in the last 2 million years

Abstract

The Iberian Peninsula is almost surrounded by the sea and is topographically and ecologically variable. These factors will have impacted on both the distribution and dispersal patterns of large mammals (including hominins) within Iberia, and are considered in detail in this paper. There are two routes of mammalian dispersal into Iberia: across the Pyrenees and across the Gibraltar Strait. With an increasing interest in the possible use of coastlines by early hominins the latter route has been the focus of much discussion. However, the arguments are limited by the relative lack of hominin remains and archaeology from the Early Pleistocene. This paper takes a wider perspective to hominin dispersals by examining what is known of the evolution and movements of other taxa in Iberia and how these may inform our understanding of the hominin fossil record. Beginning by briefly reviewing the present day and Pleistocene glacial and interglacial vegetation of Iberia, it then considers the large-mammal fauna. Particular attention is paid to the potential routes of movement for terrestrial animals in and out of the peninsula, and the evidence for each route is assessed. Iberia was a refuge for temperate species during the Quaternary glacial cycles and movements of Quaternary faunas are reviewed in the light of modern phylogeographic analyses and studies of fossil assemblages. Iberian faunas are highly variable, with some absences of otherwise widespread European animals, but cold-phase taxa such as reindeer and woolly rhinoceros did cross the Pyrenees. It seems that the large mountain ranges were less a barrier for the dispersal of these taxa than the line which today forms the limit of the summer drought. Iberia also provided the last refuge for extinct species such as the Neanderthals and endangered extant species such as the Iberian lynx.