Effects of flooding and its temporal variation on seedling recruitment from the soil seed bank of a Neotropical floodplain

ABSTRACT

Evaluation of the effects of flooding on seedling recruitment from seed banks helps in understanding vegetation regeneration in floodplains. We studied the effects of simulated flooding on richness and abundance of, and temporal variation in, seedling recruitment from the soil seed bank of a floodable savanna of the Pantanal wetland, under two conditions: 1) Post-flood = inundated for 30 days followed by irrigation; 2) Non-flooded = only irrigated. We recorded emerged seedlings biweekly for 120 days and found a total of 124 species for the two treatments, the most abundant species were annual herbs (e.g., Richardia grandiflora and Euploca procumbens) and annual graminoids (e.g., Digitaria ciliaris and Cyperus haspan). Flooding positively influenced seedling richness and abundance, while seedling emergence from the non-flooded soil was slower, but continued during all periods. The different temporal patterns between treatments showed that flooding increases the abundance of emerged seedlings and acts as a trigger for explosive recruitment shortly after water depletion.

Keywords
Pantanal; plant ecology; savanna regeneration; seedling abundance; wetland