Small pools on the sides of forest roads as breeding sites for the Tohoku salamander(Hynobius lichenatus): a case study in the Shonai region of northeastern Japan.

We investigated the potential of small pools on the sides of forest roads in the Shonai region of northeastern Japan as breeding habitats for the near threatened species Tohoku salamander(Hynobius lichenatus). We surveyed the presence of egg sacs of the salamander in pools from April to June 2022. The relationships between the number of egg sac pairs and environmental factors were analyzed using a Zero-inflated negative binomial model(ZINB). Furthermore, we conducted a population survey of the salamanders in pools where egg sacs were found during August to September 2022 before the metamorphosis of larvae, to determine their survival to larval stage at the egg-laying sites. Egg sacs were detected in 85 out of 250 surveyed pools, suggesting that pools on the sides of forest roads are used as egg-laying sites by the salamanders. The ZINB analysis revealed positive correlation of number of egg sacs with litter availability, water depth, low number of Japanese fire-bellied newts, proximity to forest, and lack of road pavement. Of the surveyed pools where egg sacs were identified, 75 were further examined for the presence of larvae and larvae were found at 20 sites. This suggests that larvae could not survive at many egg-laying sites on the sides of forest roads. © 2023 Ecology and Civil Engineering Society. All rights reserved.