Effects of substrate type, moisture and its interactions on soil seed survival of three Rumex species

Seed bank persistence plays a highly relevant role for population dynamics. The impact of interacting environmental factors on seed longevity has only scarcely been investigated. We aimed to analyse the effects of varied soil substrate type and moisture on soil seed survival. Seeds of three Rumex species native to different habitats were buried in pots placed in open-air basins. The factors substrate (sand, loam, mud), water table depth (WTD; high, intermediate, low), time, and their interactions were investigated. Viability was tested after 6, 12, and 18 months. Seeds of R. acetosella (dry habitat) were short-term persistent with highest survival in low WTD on sand. Survival in R. acetosa (moist habitat) was very strongly reduced after 6 months with highest survival under wet conditions. R. maritimus (wet habitat) had overall long-term seed survival, where 'substrate type' had the strongest impact. Significant interactions of 'substrate type' and WTD were detected. Seed bank longevity is not a fixed species trait, but varies with environmental factors. Soil moisture, substrate type and their interactions have different effects on the studied species. Persistence-classifications ought to consider the impact of environmental factors.