The potential of the soil seed bank for the regeneration of a tropical urban forest dominated by bamboo

Isolated forest fragments are subject to natural and anthropogenic disturbances that can alter forest properties. Native bamboo species are favored by disturbances. Few studies have attempted to demonstrate the influence of bamboos regarding the availability of soil seed bank and their implications for management. The present study aims to evaluate whether the dominance and the maintenance of the forest in the early stages of succession has been facilitated by the structure of the local seed bank within an urban fragment of Atlantic forest in Brazil. We also evaluated the forest regeneration potential of the soil seed bank under a bamboo-dominated area and a control area. A total of 5181 (units) seeds were germinated, corresponding to 81 plant species in 31 families. Miconia cf. cinnanomifolia was the most abundant species in the seed bank for both forests (72.6% in control and 43.9% in bamboo-dominant). Despite the low diversity and evenness found in both areas, the seed bank in the bamboo-dominated area had higher species richness and diversity, and a heterogeneous floristic composition of shrub and tree species when compared to the control area. In both areas early-successional species of trees and shrubs dominated the seed bank (>90%). The results are discussed in terms of the regeneration ability, and it is suggested that in spite the area being a remnant with disturbed forest patches invaded by bamboos, the soil seed bank still represents an important seed source for forest regeneration.

Research highlights▶ The soil seed bank of an urban area dominated by bamboo was studied and showed a dominance by native species. Non-native species represented a low percentage of seeds in the soil. ▶ The massive flowering and die-back of the bamboo species at 7-year intervals is an important event that can represent an opportunity to recruit pioneer seeds from the soil seed bank. ▶ The density of native species may be more conspicuous in urban landscapes surrounded by other fragments due to availability of external seed sources. ▶ Our findings have important implications for conservation actions or restoration strategies.