Kyoto, Japan -- Where they could once hop and amble freely, urbanization is diminishing the habitats of amphibians. Yet, small-scale water bodies managed by people -- such as those found in the gardens of Japan's temples, shrines, and schools -- remain within urban areas, providing oases for our moist neighbors.
Though the ponds and streams found in the gardens of Kyoto's temples and shrines are maintained as cultural landscapes, their function as habitats for urban amphibians has not been fully explored. This inspired a Kyoto University-led research team to examine the habitat capacity of these gardens. The team saw their potential as biocultural aquatic landscapes, where culture and biodiversity intersect.
The researchers utilized both visual and DNA analyses in their search for local amphibians, as some species are difficult to observe directly while others are hard to detect at certain times of the year. They conducted visual surveys at 80 water bodies located within 31 temples, shrines, and associated facilities in Kyoto's Higashiyama area, which helped them identify adults, eggs, and larvae, while an auditory element helped them identify calls. The team also performed environmental DNA analyses at 43 of these water bodies, in addition to recording the type of water body, water source and flow, distance from forest, riparian structure, and the presence or absence of carp in order to analyze the relationship between species and environmental conditions.
Ultimately the scientists were able to identify seven species of frog -- six native and one non-native -- and one species of newt inhabiting Kyoto's gardens. They also observed that each species' relationship with its environmental conditions varied. Furthermore, the team's use of both visual and DNA analyses proved to be complementary: while they identified the species Rana tagoi solely based on environmental DNA, direct observation of the frogs' eggs and tadpoles was essential for confirming reproduction.
"We observed amphibians at considerably more waterbodies than we had expected, and this made us realize just how rich in wildlife the local watersides -- including those around temples and shrines -- truly are," says first author Kae Okoshi.
These findings provide an opportunity to reconsider these cultural water features as habitats for biodiversity, and have the potential to influence the management of school and park ponds, as well as the assessment of sites promoting coexistence with nature.
"We intend to expand our work to include those who own and manage gardens to jointly develop approaches to waterside management that value both cultural heritage and biodiversity," says Okoshi.
