Reconstructing historical freshwater geochemistry to inform the conservation of the Natterjack Toad (Epidalea calamita) in Surrey, UK

Abstract

The Natterjack toad (Epidalea calamita) is a small, rare amphibian native to Europe. In the UK and Ireland they are now largely confined to sandy heaths, coastal dunes, and shallow warm ponds, with only a limited number of breeding sites remaining following historical habitat loss. Populations have declined due to habitat fragmentation, hydrological changes, and breeding
site scarcity (Abrahams et al., 2026), making the species a conservation priority and challenging to monitor using traditional methods. They are also sensitive to changes in water chemistry, including acidification, which can affect egg and larval survival (Beebee et al., 1990). As a result, the Natterjack Toad is a protected species in the UK and remains a key focus of habitat restoration and long-term freshwater management efforts.