# Osmundastrum cinnamomeum population differences in three habitat types in South Korea

## TL;DR

This study finds that montane wetlands are the best habitat for Osmundastrum cinnamomeum in South Korea, but climate change and human activity threaten these areas.

## Contribution

The study identifies montane wetlands as the optimal habitat for O. cinnamomeum and highlights threats from anthropogenic disturbances and climate change.

## Key findings

- Montane wetlands had the highest biomass and reproductive investment for O. cinnamomeum.
- High-elevation mountains supported better growth but limited reproduction due to low light.
- Low-elevation habitats had factors like high temperature and human disturbance that hinder fern survival.

## Abstract

Most ferns occur in moist and shaded environments; their relatively narrow band of survival conditions increase their extinction risk under Anthropocene-linked climate change. Osmundastrum cinnamomeum (L.) C. Presl is a perennial fern that has a natural distribution primarily encompassing the East Asian mountains. In this study, we characterized the vegetation and environmental factors in low- and high-elevation mountain ranges and montane wetlands to elucidate the optimal habitat for O. cinnamomeum. We found that populations of O. cinnamomeum developed better in high-elevation mountains than in low-elevation mountains. However, the low light intensity in high mountain forests reduces opportunities for reproduction. The montane wetlands recorded the highest biomass among the three habitat types, and the investment in reproduction was also significantly higher. The montane wetlands also showed higher light intensity, substrate fertility, and water content. Overall, the montane wetlands were found to be the optimal habitat for O. cinnamomeum. At lower elevations, lower precipitation, higher temperatures, human disturbance, and low substrate water could be factors limiting the expansion of this fern's distribution. Our study points to the importance of conserving montane wetlands to prevent the extinction of ferns.

•Montane wetland is the optimal habitat of the Osmundastrum cinnamomeum.•Anthropogenic disturbances and high temperatures threaten Korean montane wetlands.•Osmundastrum cinnamomeum could become extinct due to habitat loss.

Montane wetland is the optimal habitat of the Osmundastrum cinnamomeum.

Anthropogenic disturbances and high temperatures threaten Korean montane wetlands.

Osmundastrum cinnamomeum could become extinct due to habitat loss.