Species distribution modelling
The present breeding distribution of L. c. superciliosus was
modelled based on presence-only data and seven non-correlated
bioclimatic variables using the MaxEnt algorithm (Figure 3). Minimum
training presence omission rates for test localities were 1.9% and the
model was evaluated to estimate suitable habitat without problematic
overfitting. The present prediction of suitable areas (Figure 3a)
reflected the taxon’s known breeding range according to Lefranc &
Worfolk (1997).
Projection of the model to three climatic models of the LGM (Figure
3b-d) inferred that the coastal area of the currently submerged ECS
continental shelf, and an inner continental range corresponding to the
present CRECS, were predicted to be suitable breeding habitat forL. c. superciliosus . Suitability for these regions was estimated
to be relatively lower than in the Japanese archipelago, within which
suitable breeding habitat receded southwards but largely remained during
the LGM. Most of the Ryukyu islands were not predicted to be suitable
for the species during the LGM, based on our model.