A couple of days ago, my PI, Prof. Andrea Manica (University of Cambridge), presented a webinar. He talked about pastclim, our piece of software to easily access and manage palaeoclimatic data. He gave a general overview about the palaeoclimatic reconstructions included in it, presented the package and gave examples of how palaeoclimate can be used to address questions related to evolution, palaeoecology and migrations.
What happened to temperate ungulates in Europe during the climatic fluctuations that have affected the last 50,000 years? To answer this question we compiled a database of radiocarbon dates associated with remains of horses, aurochs, deer and wild boars dated between 47,000 and 7,500 years ago (so as to exclude domesticated individuals).
We then developed a new method to reconstruct their (realised) ecological niche, while also testing for changes through time.
Analysing our data we found that all four species changed their niche, mainly during the Last Glacial Maximum (LGM) or shortly after, in a pattern consistent with individual habitat preferences. The distribution of horses and deer (cold-adapted species) spread eastwards until the LGM, while aurochs and wild boar are restricted to Central and Western Europe. The four potential distributions became more similar from the LateGlacial (but it does not imply the same about their preferences).
In more general terms, with this study we demonstrate that even large species, with long generation times, can change their niche in the course of a few thousand years. This must suggest extreme caution when assuming that the ecological niche remains constant both when reconstructing the past and when forecasting the future.
Predicting the effects of future global changes on species requires a better understanding of the ecological niche dynamics in response to climate; the large climatic fluctuations of the last 50,000 years can be used as a natural experiment to that aim. Here we test whether the realized niche of horse, aurochs, red deer, and wild boar changed between 47,000 and 7500 years ago using paleoecological modelling over an extensive archaeological database. We show that they all changed their niche, with species-specific responses to climate fluctuations. We also suggest that they survived the climatic turnovers thanks to their flexibility and by expanding their niche in response to the extinction of competitors and predators. Irrespective of the mechanism behind such processes, the fact that species with long generation times can change their niche over thousands of years cautions against assuming it to stay constant both when reconstructing the past and predicting the future.
