Abstract

Quercus chungii is an endemic tree species in China, rare and endangered in subtropical areas of China. Understanding its population structure and temporal dynamics is crucial for conserving and restoring Q. chungii population and its associated ecosystems. However, large knowledge gaps remain about its population structure and temporal change, and its key demographic rates across size classes. In this study, we investigated the population structures of Q. chungii in 2013 and 2023 in a nature reserve specifically established to better conserve Q. chungii and its associated ecosystems. We found that Q. chungii increased in its overall abundance, frequency and tree size in the past decade, suggesting active regeneration and fast growth rate of this species and the effectiveness of past conservation efforts. The age structure in 2023 shows a pyramid shape, with a sharp decline in the numbers of individuals from germinated seeds to seedlings and from seedlings to saplings. These lead to the low numbers of seedlings and saplings and high age-specific death probabilities at the early developmental stages. These results indicate potential risks of future population decline. These risks may have already manifested over the past decade, as a high mortality rate during the seedling-to-sapling transition could be one of the primary reasons contributing to the decreased proportion of saplings in 2023 compared to 2013. We propose that future studies may benefit from in-depth studies on the regeneration processes of Q. chungii by considering seed predation and germination under changing climate. This study improves the prediction of population development of Q. chungii and provide theoretical guidance for the conservation of Q. chungii.