Is the endangeredApium repens(Jacq.) Lag. rare because of a narrow regeneration niche?

Abstract

AbstractThe conservation of rare plant species is an important aspect of global biodiversity protection, but in many cases these species and the reasons why they are rare are poorly understood. The perennial umbelliferApium repensis generally regarded to be a rare species all over its European range. We hypothesized that its rarity might be caused by a restricted regeneration niche, that is, highly specific requirements for sexual regeneration, low seed dispersal potential and low endurance capacity of seeds in the ground. We conducted several experimental investigations on its germination ecology, hydrochorous dispersal potential and soil seed bank properties.Apium repensshowed high germination success under a variety of abiotic conditions. Either light or cold‐wet stratification was necessary to stimulate germination. Seeds were able to float for more than 50 days when protected from precipitation, and soil seed bank sampling revealed that at least some seeds ofA. repenswere contained in soil depths of up to 10 cm. Overall, our findings do not support the hypothesis that the rarity ofA. repensis caused by highly specific requirements for its sexual regeneration. Nonetheless, its germination ecology should be considered when designing conservation measures for this endangered species.