Revisiting Ancient Forests: Insights From the Mid-Pliocene to Predict Future Climate Impacts

Abstract

Aim

The potential analogues in Earth's past may hold insight on how modern European forests will react to different levels of future warming. There is a lack of comparison between future warming and its most recent climate analogue 3.25 million years ago during the mid-Piacenzian warm period. We have attempted to fill this knowledge gap by modelling the zonation of woody plant communities during the mid-Pliocene and comparing it with their current distribution and predictions of their future distribution.

Location

Europe.

Time Period

3.25–3 million years ago, 1970–2000, and 2081–2100.

Taxon

European tree species.

Methods

In this study, we selected 15 European tree species from three main European forest ecosystems: Mediterranean, temperate and boreal species that had ancestors present in Europe during the mPWP. Then we applied an ensemble model using climatic data from the mPWP, modern and two future climate scenarios. In order to compare the models, we assessed the overlapped area as well as Dutilleul's modified t-test in order to assess the spatial similarities in forest communities distribution between the mPWP and future warming.

Results

Our results showed that there is a clear northern trend in the northward shift of forest communities under all warming scenarios. Across all species, there is a clear drop in suitable area with the exception of Mediterranean species, where suitable area increased in all warm scenarios. When comparing the mPWP with future warming, there is evidence to support that RCP 4.5 will potentially exhibit similar conditions, while RCP 8.5 may result in highly novel habitats.

Main Conclusions

Although mid-Pliocene conditions are more analogous to the RCP 4.5, it raises an urgent ecological concern for adaptive forest management. Increasing temperatures and uncertain precipitation patterns have the potential to aid the expansion of Mediterranean forest communities while fragmenting temperate and boreal forest communities throughout central Europe.