Predicting the distribution of released Oriental White Stork (Ciconia boyciana) in central Japan

The Oriental White Stork (Ciconia boyciana) is one of the species threatened by mainly anthropogenic factor and their habitats are considered to be conserved. The first reintroduction of the species in Japan occurred in 2005. But as the species’ natural wetland habitats are declining, the birds now prefer to forage in rice paddies. Thus, restoring the paddy-dominated landscape is key for further success in the reintroduction program. In addition, a quantitative method is urgently needed to assess how much suitable habitat is available and where it is located. In this study, we identified environmental factors that affect the distribution of the Oriental White Stork and produced the first predictive spatial distribution map using 2-year satellite tracking data of reintroduced individuals. The maximum entropy (MaxEnt) approach was used to model the species’ distribution at the landscape scale (1 km × 1 km grid cells). We identified six relevant environmental variables. Our results highlight the proportion of area of rice paddies as alternative wetland habitat as the most influential variable affecting the distribution positively. Landscape diversity represented by a complex mosaic of paddies and forest is also important for the species, as total length of paddy-forest edge also had a positive effect on habitat suitability. Our predictive distribution map cannot entirely provide distribution; however, it may be valuable information when considering where should be conserved as habitat to maintain the Oriental White Stork population in Japan.