Linking water quality with amphibian breeding and development: a case study comparing natural ponds and Sustainable Drainage Systems (SuDS) in East Kilbride, Scotland

Amphibians have declined due to habitat loss and alteration. Sustainable Drainage Systems (SuDS) provide potential habitat for amphibians in urban landscapes. However, the contaminants they accumulate may cause increased pollutant exposure, and limited research has addressed whether differences in water quality between SuDS and natural ponds might restrict their use by amphibians. This study aimed to explore the effects of water quality on amphibian breeding and development in SuDS and natural ponds in East Kilbride, Scotland. A generalised linear modelling approach was employed to determine sources of variation in common frog (Rana temporaria) breeding and development in relation to pond size, pH, electrical conductivity (EC), chlorophyll and heavy metal concentrations. Key findings included that EC indicative of salt pollution was higher in SuDS than natural ponds, amphibians bred in both site types, but frog spawn clump densities were lower in SuDS, and tadpole development rates were higher in SuDS sites but decreased when aluminium concentrations exceeded concentrations those of surface water standards. However, pond desiccation was a significant element in the 2018 study year. It was concluded that natural ponds and SuDS varied in water quality but were important in supporting amphibian populations. However, water quality might influence amphibian development more than breeding attempts; implications and management recommendations are highlighted based on these observations.