Small mammals of the Holocene sequence of Postes Cave (SW Spain): biogeographic and palaeoenvironmental implications for southwestern Iberia

Postes Cave in SW Spain (Extremadura) displays a Holocene archaeostratigraphic sequence radiocarbon-dated to between <i>c</i>. 8.5–4 cal kyr BP (Mesolithic-Chalcolithic). The sediments collected at two areas within the cave yielded small mammal remains belonging to eleven species of rodents, ‘insectivores’, lagomorphs and chiropterans. This small mammal fossil assemblage is one of the few known to date in the southwest of the Iberian Peninsula. Preliminary taphonomic analysis and previously published data suggest that the remains were accumulated by the predatory activity of Eurasian eagle owls and small to medium-sized carnivores such as red foxes. The palaeoenvironmental and palaeoclimatic reconstructions performed show stable conditions with slight variations during its time span, suggesting an initial scenario of open forested habitats during the Mesolithic and Neolithic which progressively decreased in favour of more open habitats during the Chalcolithic coinciding with human-induced changes of the landscape and with the aridification trend of this period. The presence of <i>Microtus cabrerae</i> and <i>Crocidura suaveolens</i> in the assemblage is noteworthy since they are now extinct in this region. The plausible causes and the processes of these extirpations are discussed.