Ecological change and the extinction of the Levantine Neanderthals: implications from a diachronic study of micromammals from Amud Cave, Israel

Abstract

It has been hypothesized that the climate shift associated with the Heinrich 5 event (H5) and the decrease in productivity throughout MIS 4 contributed to the demise of Neanderthals from the Levant. The Middle Paleolithic stratigraphic sequence of Amud Cave (Israel) spans MIS 4 and the transition to MIS 3 and contains Neanderthal skeletal remains as well as microfaunal assemblages, often used in the literature as reliable paleoecological proxies. This combination offers a unique case study to address the question of the effects of climate on Neanderthal population dynamics. Here we present a diachronic study of the rodent assemblages from Amud Cave, Israel, using taphonomic and nested hierarchical paleoecological models to test the hypothesis of a decrease in environmental productivity throughout the Amud sequence. Results suggest that there is no change in high-level presence–absence and rank abundance of rodent species throughout the sequence of Amud Cave, but there is change in low-level relative abundance of four taxa. Paleoecological analysis suggests that while all the stratigraphic sub-units of Amud Cave can be assigned to a Mediterranean biome, an apparent trend of decrease in grasslands proportions throughout the sequence is discordant with other regional paleoecological proxies. Taphonomic analysis reveals that this may be attributed to specific predator preferences of rodent prey, and thus does not reflect the true shift in paleoecology throughout the temporal sequence represented in the cave. The high-level overall stability in rodent community suggests that climatic shifts during the MIS 4–3 transition were of a magnitude that did not have a major impact on small mammals in the region. Such results are consistent with evidence from analysis of large mammal community and vegetal remains in Amud and contemporaneous Middle Paleolithic cave sites, and suggest that climate change may not have had the hypothesized effect on Neanderthal extinction in the Levant.