Terrestrial bromeliads as seed accumulation microsites in a xerophytic forest of Southern Chaco, Argentina

Abstract

The understory of the Schinopsis balansae forests of Southern Chaco is frequently covered by dense populations of two bromeliad species (Aechmea distichantha and Bromelia serra). These bromeliads usually act as traps capturing propagules and litter falling from the canopy. Some populations of these bromeliad species have been removed to ease cattle management, without considering their possible effects on forest regeneration. Therefore, the objective of this work was to evaluate the importance of both bromeliads as microsites for seed accumulation of woody and herbaceous species. Ten plots with bromeliads were selected, where one soil sample and one plant of each species were taken. From the material collected among bromeliad leaves, the seeds and propagules were separated. Likewise, soil samples were washed and the seeds were separated from the litter collected. Seeds were determined to morphospecies and counted. There were 352 seeds (230 on bromeliads and 122 in the soil) from 48 species (10 woody and 38 herbaceous species). Seed abundance of woody species was higher on bromeliad plants (70 seeds) than on the soil (six seeds). In contrast, a higher richness of herbaceous species was recorded on the soil. Therefore, both bromeliads seem to be important microsites for seed accumulation of woody species. However, it is not known whether bromeliads are a safe site for seedling establishment.