Monitoring the Growth and Habitat Shifts of Epiphyllous Liverworts in Subtropical Forests of China.

Understanding the extent to which species can adjust their ranges in response to climate change and track areas of suitable climatic conditions is vital for conservation efforts. Nonetheless, the observed changes in species distribution may also result from inadequate field data. This is particularly relevant for epiphyllous liverworts, which exhibit a poikilohydric lifestyle that makes them more vulnerable to climatic fluctuations than many other higher plants. Furthermore, their small plant size increases the chances of under-detection in epiphyllous liverworts compared to other plant groups. To enhance our understanding of how species distribution is influenced by climate change, establishing long-term monitoring plots is essential. In this study, we utilize the BEST platform (Biodiversity along Elevational Gradients: Shifts and Transitions) to furnish empirical evidence regarding the habitat shifts of epiphyllous liverworts along the elevational gradient of Mt. Tianmu. To identify the specific microclimatic conditions vital for the growth and development of epiphyllous liverworts, we conducted a transplant experiment. Our systematic observations from the permanent monitoring plots (2018-2022) led to the discovery of a new population of epiphyllous liverworts located at an elevation of 1130 m. By analyzing in situ microclimatic data on air temperature and moisture, collected consistently over 5 years (2017-2022), we characterized the mean, minimum, and variability of the microclimatic conditions essential for epiphyllous liverwort growth. Additionally, results from elevation transplantation experiments underscore the importance of incorporating dispersal constraints when modeling the species distribution of epiphyllous liverworts for precise predictive outcomes. Our results highlight the importance of long-term monitoring permanent plots in predicting the effects of global changes on species habitat shifts, and underscore the necessity for comprehensive investigations of the distribution of epiphyllous liverworts at the northern boundary of subtropical evergreen broad-leaved forests in China.