Spatial Distribution and Ecological Assessment of Vegetation-Climate Zone Ecotones in the Temperate Forests of South...

Ecotones are transition zones that integrate environmental gradients and play an important role in biodiversity conservation; however, within the context of South Korea, their ecological functions and spatial characteristics remain insufficiently quantified at the national scale. Scientific evidence is needed to support their inclusion in protected area planning. In this study, we quantified the spatial distribution and ecological characteristics of ecotone zones (EZs) across vegetation-climate zones in the temperate forests of South Korea and examined their associated biodiversity patterns and species turnover. Entropy-based spatial classification was conducted to delineate the EZs. Environmental and compositional differences among zones were tested using ANOVA and multivariate ordination (CCA, MRPP), while species turnover and community-assembly processes were examined through zeta-diversity-based model comparisons (RMSE, AIC). The EZs exhibited mixed characteristics of multiple vegetation-climate zones, showing intermediate environmental conditions and transitional species composition consistent with a buffering role. EZs showed high species richness (607.8 ± 9.6 species per grid) that did not differ significantly from the Northern Temperate Zone (NTZ) (p = 0.069), and CCA explained the compositional gradient, with the first two axes accounting for 86.5% of the constrained variance (CCA1 = 57.2%, CCA2 = 29.3%). MRPP results indicated the greatest compositional overlap between EZ and the Central Temperate Zone (A = 0.0317), the lowest agreement value among all pairwise comparisons. The zeta-diversity analysis revealed unimodal patterns with intermediate turnover and partial stability dominated by stochastic processes. These patterns indicate that EZs are transition zones associated with high species richness and intermediate turnover. Overall, our findings suggest that EZs may warrant consideration in protected-area prioritization and provide a quantitative basis for identifying them at the national scale.