The study evaluates the ability of stable isotopes (δ¹³C and δ¹⁵N) and sugar biomarkers to distinguish Erica from the dominant vegetation of the Bale Mountains in order to reconstruct the past extent of Erica on the Sanetti Plateau. No significant differences in stable isotopes are found between the dominant plant species. Although Erica is characterized by quite high (G+M)/(A+X) ratios, it cannot be unambiguously distinguished from other plants due to degradation and soil microbial effects.

Chemotaxonomic identification of keystone plant species in the Bale Mountains are possible using lignin phenols. However, Erica could not be differentiated chemotaxonomically from all other investigated plants using n-alkanes. Unambiguous characteristic patterns of lignin phenols reflected in the plant samples were not sustained in the organic layers and mineral topsoils. This is due to degradation and organic matter inputs by roots. Therefore, the past extent of Erica is still speculative.

For this study we systematically investigated the molecular pattern of leaf waxes in litter and topsoils along a European transect to assess their potential for palaeoenvironmental reconstruction. Our results show that leaf wax patterns depend on the type of vegetation. The vegetation signal is not only found in the litter; it can also be preserved to some degree in the topsoil.

Stable water isotopes (18O/16O and 2H/1H) are invaluable proxies for paleoclimate research. Here we use a coupled 18O/16O and 2H/1H biomarker approach based on plant-derived sugars and n-alkanes. Applying this innovative approach to a topsoil transect allows for (i) calculating the deuterium-excess of leaf water as a proxy for relative humidity and (ii) calculating the plant source water isotopic composition (~precipitation). The approach is validated by the presented climate transect results.