Exploring the role of a Mediterranean transhumance drove road as shelter for amphibian breeding

Abstract

Amphibians face global population declines due to environmental degradation and habitat loss, particularly impacting breeding water bodies. Thus, we hypothesise that water bodies associated with traditional pastoralist practices, such as those along drove roads used for transhumance (e.g. ponds and troughs), may play a crucial role in supporting amphibian assemblages. Conducted in one of the main drove roads still in use in Spain (the Conquense Drove Road, hereafter CDR), this study evaluated the conservation condition and contribution of the CDR water bodies to amphibian breeding assemblages at a landscape scale. We also explored the influence of landscape (land use cover) and local (water body characteristics) variables on the occurrence of breeding amphibians within and outside the CDR. Results confirm that the CDR provides a significantly higher proportion of functional water bodies to the landscape compared to its surroundings, providing highly valuable refuges for amphibians against threats caused by land use intensification. This key function of the CDR in the maintenance of amphibian breeding points persists despite the observed lack of continuity of water bodies along its route. Ponds and the most naturalized troughs (the minority of them) were identified as the most suitable habitats, supporting species such as Discoglossus galganoi, Pleurodeles waltl, Epidalea calamita, Hyla molleri, Pelobates cultripes, Pelodytes punctatus, and Pelophylax perezi. Only the latter two were found in troughs. While pond creation and restoration should be prioritized due to their higher suitability for amphibians, we demonstrated that troughs still serve as complementary habitats and refuges if properly managed. We recommend ensuring a minimum hydroperiod, promoting the development of sediment and macrophytes, and implementing access ramps for terrestrial wildlife.