Sprouting as a survivorship trait for woody plants: The influence of trunk size and neighbourhood competition

Sprouting is an insurance life strategy for woody plants to achieve persistence that has received much attention previously in harsh environments and plantation forests. However, our understanding of the characteristics, influencing factors and ecological functions of this key functional trait of woody plants remains limited in species‐rich forests. Here, we explored the sprouting characteristics, assessed the effect of sprouting on the mortality rates of woody plants of different sizes and determined the influence of trunk size and neighbourhood competition on sprouting in a 50‐ha tropical natural rainforest on Barro Colorado Island (BCI), based on 26,349 woody plants with sprouts, that is, sprouters. Our results showed that there was a trade‐off between the size of sprouts and their quantity. Sprouting significantly decreased the mortality rate of saplings and small woody plants, while this benefit diminished for medium‐sized and large individuals. In addition, trunk size was the strongest predictor of sprouting, with sprouting capacity declining as trunk size increased across woody plants with sprouts and for nearly 90 percent of 40 species (each with over 100 sprouting individuals) as well. Apart from trunk size, neighbourhood competition also had a weak negative effect on the sprouting capacity. Our findings reveal the size‐dependent effect of sprouting on mitigating mortality and provide insight on the self and neighbour limiting characteristics of sprouting in species‐rich forests. Sprouting is a key functional trait enhancing survival of woody plants during early life stages. We emphasize the importance of considering this key functional trait of woody plants in future studies to better understand life strategies of plants and trait spectrum. Read the free Plain Language Summary for this article on the Journal blog.