Following The Niche: Reconstructing 32,000 Years Of Niche Dynamics In Four European Ungulate Species

Abstract An understanding of how ecological niches can change through time is key to predicting the effect of future global change. Past climatic fluctuations provide a natural experiment to assess the extent to which species can change their niche. Here we use an extensive archaeological database to formally test whether the niche of four European ungulates changed between 40 and 8 kya (i.e. before major anthropogenic habitat modification and excluding the confounding effect of domestication). We find that niche change depended on habitat. Horse and aurochs, which are adapted to open environment, changed their niche after the Last Glacial Maximum, and it is unclear whether this was the result of adaptation, or an expansion of the realized niche as a response to the extinction of other megafauna (competitors and predators) that shared the same habitat preferences. On the other hand, red deer and wild boar, which prefer close and semi-close habitats, did not change their niche during the same period; possibly because these habitats have experienced fewer extinctions. Irrespective of the mechanism that might have led to the observed niche changes, the fact that large mammals with long generation times can change their niche over the time period of thousands of years cautions against assuming a constant niche when predicting the future. Significance statement When predicting species responses to future change, it is often assumed that their habitat preferences (i.e. their niche) will not change. However, it is strongly debated whether this is reasonable. Here we show that two out of four species of large European ungulates changed their niche following the Last Glacial Maximum, possibly as a response to the reorganization of animal communities that resulted from numerous megafauna extinctions. This finding cautions against the assumption of a constant niche, highlighting that, to predict the future, we will ultimately need to understand the mechanisms that underpin the success of a given species under different climatic conditions.