Traditional water structures in villages support amphibian populations within a protected landscape

Abstract

Amphibians are among the most globally threatened vertebrates, with habitat loss and degradation being the primary drivers of their decline. While natural waterbodies are essential for amphibian survival, artificial habitats can also serve as important refuges, particularly in human-altered landscapes. This study investigates the role of artificial waterbodies in supporting amphibian populations within villages and disturbed areas of Peneda-Gerês National Park (PNPG), a protected area in northern Portugal. We surveyed 162 waterbodies, 68 artificial (tanks, drains, fountains, and cave-like structures) and 94 natural (ponds, streams, stream pockets, and caves) sites within human-altered areas to assess community composition, species richness, Shannon diversity, relative abundance, proportion of occupied sites, and breeding activity. We recorded 10 amphibian species, with species composition showing moderate overlap between the two habitat types, indicating both shared and distinct species assemblages. Natural waterbodies had higher observed species richness (nine species) than artificial sites (seven species). Shannon diversity was greater in natural waterbodies for adults, while juvenile/larvae diversity was greater in artificial habitats. Rana iberica was the most widespread species, found across all waterbody types but predominantly in natural sites. Salamandra salamandra juveniles/larvae were also primarily found and bred in natural habitats, especially stream pockets. In contrast, Lissotriton boscai and Triturus marmoratus were more commonly found and bred in artificial waterbodies, particularly historic water tanks. Natural waterbodies had a higher proportion of their sites occupied (76.6%) compared to artificial ones (51.5%), with stream pockets having the highest at 96.6% and other natural sites around two-thirds. Among artificial sites, tanks were highest with 62.5% occupied. Breeding occurred in one-fifth of surveyed sites, with breeding events recorded in half of stream pockets and over a quarter of tanks. Tanks supported the highest number of breeding species (four of five), compared to three in natural habitats. These findings highlight the importance of water tanks, traditionally used for laundry and water storage, in supporting amphibians in PNPG. They underscore the need to conserve both natural and artificial habitats to protect amphibian biodiversity, especially in human-altered landscapes where artificial waterbodies provide crucial refuges as climate change reduces natural breeding sites.