The factors affecting the distribution of wet-paddy, ill-drained during the non-irrigation season, which are important spawning grounds for Rana frogs were estimated. The field study was conducted in Toyota City, Aichi Prefecture, Japan in 2019. We traveled along roads and recorded the presence or absence of puddle in the rice fields, cultivation conditions, and farmland consolidation. DEM (10 m), vegetation maps (1:25,000), and GIS data of the road were used to extract geographic factors. The response variable was the presence or absence of puddles in each paddy block, the explanatory variables were categorical variables such as yatsuda (valley paddy field) or not, farmland consolidated or not, forest edge or not, cultivated or abandoned, and quantitative variables such as elevation, slope, TWI, percentages of forest and and paddy area, and road density within concentric circles. The concentric circles of seven different radii ranging from 50 to 600 meters were used. Hierarchical Bayesian models with spatial random effects were fitted using the INLA and SPDE approaches to account for spatial autocorrelation of residuals. In the model with the smallest DIC, the percentage of forest area with a radius of 200 m, yatsuda type, no farmland consolidation, and forest edge increased the wet-paddy ratio, and intermediate elevation decreased the ratio. A spatial effect with a range of 10.5 km was observed, with higher rates of wet-paddy field in the northern mountains and southern foothills, and lower rates in the middle region.

In order to clarify the effects of long-term foraging pressure by sika deer on forest vegetation, we conducted a study on changes in forest area over a 31-year period by reading aerial photographs taken in 1975 and 2006 at Kinkazan Island in Miyagi Prefecture, which is inhabited by a high density of deer (40-60 deer/km²). As a result, the forest area was greatly reduced, the fir- and beech-forest areas, which the typical forest vegetation, had not recovered 12.8 ha and 14.9 ha, respectively. The rate of decrease was about 0.4-0.5 ha/year, and the decrease was mostly at around the forest edge near the grassland. On the other hand, forest expansion was more pronounced in the area where vegetation protection fences, but was also observed in areas where no fences were installed, probably due to the sheltering effect of the non-preferred plants.