Bamboo dieback and tree regeneration responses in a subtropical forest of South America

Bamboos’ vegetative growth are frequently associated to negative effects on tree recruitment and survival and despite this process, the effects of bamboo dieback after flowering events are poorly understood due the rarity of these events. 2 years after the massive flowering of the woody bamboo Merostachys multiramea in a southern South America subtropical forest, we compared changes in environmental conditions; tree species regeneration and production of new culms in canopy gaps resulted from bamboo dieback and areas of continuous canopy allowed by sparse bamboo cover. We observed sharp differences in environment conditions mainly resulted from differences in canopy openness and a NPMANOVA revealed differences among the stands regeneration directions (species composition and density). Average density, number of culms per sapling and total height of M. multiramea did not differ between stands, although slight differences were detected with increasing values toward opened sites.Canopy gaps resulted from bamboo dieback showed higher species richness and diversity when compared to closed canopy without bamboo. After 2 years, the massive bamboo flowering and dieback resulted differences in several environmental conditions, leading to distinct regeneration directions with higher diversity toward opened areas.

Research highlights▶ Bamboo dieback led to distinct regeneration patterns toward opened areas. ▶ Bamboo dieback increased light levels in the understory with canopy discontinuity. ▶ Species richness and diversity increased in opened areas. ▶ Either tree-fall gaps or bamboo-dieback gaps are critical regeneration sites.