Figure 1.
Locations of 313 study transects across the main four islands of Japan.
Figure 2.
Relationship between species richness and proportion of forest cover at a landscape scale.
(a) total species; (b) wide-ranging species; (c) narrow-ranging species. Regression lines are based on the estimated coefficients in the best simultaneous autoregressive model, using mean values other than the proportion of forest cover at the landscape scale.
Table 1.
Z values (estimates/standard errors) of linear (L) and quadratic (Q) terms of each variable in the best simultaneous autoregressive models for total species richness and each species richness group at four landscape scales.
Figure 3.
Response of each species to proportion of forest cover at a landscape scale.
(a, c) Relationships between abundance of each species and proportion of forest cover at a landscape scale and (b, d) pie charts showing the proportions of species with the four categories of response type (open-habitat species, mosaic-habitat species, forest species, and no response) among (a, b) 38 wide-ranging species, and (c, d) 19 narrow-ranging species. Regression lines for each species were calculated in the same way as those for species richness (see explanation in the caption to Figure 2). Criteria for categorization of each species according to the proportion of forest cover are given in the text.
Figure 4.
Effect of interaction between annual mean temperature and proportion of forest cover on the richness of narrow-ranging species.
For narrow-ranging species, the definition of 100 grids is used (see Appendix S2 in File S1). Each point represents the relationship between the richness of narrow-ranging species and proportion of forest cover in each transect. Regression lines are based on the coefficients estimated with the simultaneous autoregressive model that incorporated the interaction term between these variables, at low temperature (upper 2.5% in the range of values in annual mean temperature, dotted line), mean temperature (50%, solid line), and high temperature (97.5%, broken line). Model performance is shown in Appendix S9 in File S1.
Figure 5.
Relationship between number of habitat types used by a species and range size.
For range size, the number of 20-km-square grids occupied by the species (obtained from [27]) is used for 107 out of 113 terrestrial bird species in Japan (except for six raptor species without range-size data). Values inside bars and error bars indicate sample size and standard error, respectively.