抄録
The red-clawed crab Chiromantes haematocheir is a semi-terrestrial species in the family Sesarmidae distributed from Aomori Prefecture to Ryukyu Islands in Japan. It inhabits forest edges near coasts and estuaries, residing in burrows on slopes, embankments, and reed beds along coastal forest edges adjacent to aquatic environments. However, the population has declined significantly due to coastal and riverbank development, including concrete landfilling and road construction that disrupts access to larval release areas. Conservation efforts, such as biotope creation and habitat evaluation using C. haematocheir as an indicator, have been initiated. Studies in urban environments show that it prefers artificial water channels along forest edges while avoiding flat, bare land. This study investigates the habitat conditions around Lake Kamo, a brackish lake on Sado Island, Niigata Prefecture, utilized by C. haematocheir for burrows. A high density of burrows was observed on the grounds of Kisaki Shrine near Lake Kamo, predominantly around the bases of living and dead trees rather than near buildings or stone monuments. Tree species within the shrine grounds were identified, and burrows were counted around each. Chiromantes haematocheir showed a preference for Japanese eurya, Eurya japonica var. japonica, likely due to its shrub-like growth habit with horizontally spreading branches and leaves that provide shelter from bird predation. This study provides the first evidence of tree species preferences in C. haematocheir nesting sites. Future research in other regions could inform innovative coastal park designs and construction plans that incorporate tree species utilization as an indicator for suitable nesting environments.
https://ror.org/04ww21r56 
