# Ensemble Species Distribution Modeling of Climate Change Impacts on Endangered Amphibians and Reptiles in South Korea

## TL;DR

This study models how climate change will impact endangered amphibians and reptiles in South Korea, identifying vulnerable species and future conservation priorities.

## Contribution

The study introduces an ensemble modeling approach to assess climate change impacts on eight endangered herpetofauna species in South Korea.

## Key findings

- Amphibians rely more on precipitation, while reptiles are more influenced by temperature.
- Habitat specialists like Sibynophis chinensis face significant threats due to narrow environmental niches.
- High emission scenarios could reduce suitable habitats by 45% by the 2070s, especially in lowland plains.

## Abstract

Climate change and habitat loss threaten amphibians and reptiles worldwide, with many species facing extinction. In South Korea, eight amphibian and reptile species are officially designated as endangered, but we lack detailed information about their habitat requirements. This study used computer modeling to predict suitable habitats for these species. We found that each species has unique environmental needs: amphibians depend on precipitation patterns, especially dry season rainfall, whereas reptiles are more affected by temperature. Some species are habitat specialists with narrow requirements, making them vulnerable to environmental changes, while others are generalists adapting to various conditions. Using climate change projections, we predicted that suitable habitats will dramatically shrink by the 2070s, particularly in western lowland plains that currently support highest diversity. Northern mountain regions may become future refuges as the climate changes, but many species may not be able to reach these areas on their own because their dispersal is limited and habitats are fragmented. Under high emission scenarios, suitable habitat areas could decline by forty-five percent, but moderate emission pathways could reduce this loss by half. Our findings provide essential information for conservation planning, identifying which species need urgent protection and where conservation efforts should focus to prevent extinctions.

Climate change poses a serious threat to amphibians and reptiles, which are especially vulnerable because of limited thermoregulatory capacity and restricted dispersal. We used an ensemble species distribution modeling framework to assess habitat determinants, niche breadth, and climate-driven distribution changes for eight legally protected endangered amphibian and reptile species in South Korea. Occurrence records collected between 1997 and 2021 were combined with ten bioclimatic, topographic, and hydrological predictors, and 11 species distribution modeling algorithms (SDMs), including Random Forest and MaxEnt, were implemented and combined into weighted ensemble predictions. The weighted ensemble model showed high predictive performance (mean ROC–AUC = 0.897; overall mean across all SDMs = 0.843). Variable-importance analysis revealed clear taxonomic contrasts: reptiles exhibited approximately 1.7-fold greater dependence on temperature variables than amphibians, whereas amphibians were more strongly associated with precipitation and topographic context. Environmental niche-breadth analysis identified Sibynophis chinensis, Hynobius yangi, and Dryophytes suweonensis as narrow- or moderate-niche specialists largely constrained by precipitation of the driest month and a small set of climatic variables. Under moderate (SSP2-4.5) and high (SSP5-8.5) emission scenarios, areas of high species richness are projected to decline by 22% and 45%, respectively, by the 2070s, with distribution centroids shifting northeastward and pronounced habitat loss in western lowland plains. Priority conservation targets include S. chinensis, D. suweonensis, and H. yangi, which combine narrow niches, restricted ranges, and high climate vulnerability. These findings provide a quantitative basis for climate-adaptive conservation planning for threatened herpetofauna in South Korea.