Breeding phenology and behaviour of the Endangered Hewitt’s ghost frog Heleophryne hewitti in the Baviaanskloof World Heritage Site, Eastern Cape Province, South Africa

Abstract

ABSTRACT Given the potential impact of climate change on amphibians, there is a need to establish baseline phenological data for vulnerable species and to investigate their responses to changing climatic conditions. We recorded vocalisations of Hewitt’s ghost frog Heleophryne hewitti in the Baviaanskloof World Heritage Site, South Africa, to investigate its breeding phenology and vocalisation behaviour. Our objectives were to: 1) characterise seasonal and diel vocalisation patterns, 2) examine relationships between environmental variables and calling behaviour and 3) evaluate the effectiveness of acoustic recording as a monitoring technique. We employed automatic vocalisation recognition software to detect calls and used hurdle regression to model the relationships between environmental variables and the number of calls produced. Our study confirmed that H. hewitti is a seasonal prolonged breeder, with reproductive activity occurring from early to late spring. We found that while relative humidity seemed to influence the probability of calling, none of the weather variables appeared to have a strong influence on the number of calls produced. Acoustic monitoring combined with automatic vocalisation recognition has proven to be a viable technique for monitoring this species. Further investigation of cues for breeding initiation is required to understand the impacts of climate change on this species.