Growth Process and Mortality of Sasa borealis Seedlings over Six Years Following Mass Flowering and Factors Influencing Them.

Abstract

The sexual reproduction of Sasa borealis, a species of dwarf bamboo, occurred in central Japan from 2016 to 2017. S. borealis grows on the forest floor and serves as an important source of habitat and food for various animals. Sexual reproduction occurs in synchrony among individuals in a given area, leading to a decline in population and causing substantial disturbances to the forest ecosystem; however, the subsequent regeneration process remains unclear. In this study, we investigated S. borealis seedling regeneration over six years. Fixed plots were established in the forest in the year following the sexual reproductive event, and the growth of seedlings was monitored from seed emergence to seedling growth at the individual level. We considered biotic and abiotic factors to evaluate their influence on regeneration. We examined mammalian and arthropod foraging as biotic factors. Conversely, abiotic factors included temperature and humidity near the ground surface, solar radiation, soil conditions, and snow cover. Seedling growth was characterized by a slow rate and affected by morphological changes resulting from foraging and abiotic factors. The return of S. borealis to its presexual reproductive stage requires an extended duration. Our study provides precious information for future S. borealis conservation and management strategies.