Allelopathy in bryophytes shapes ecosystems by influencing the species composition of both vascular plants and other bryophytes. Several allelopathically active chemicals in bryophytes have been discovered since the latter half of the 20th century and laboratory studies have showed their inhibiting impact on germination, growth and establishment of surrounding plants. However, other studies failed to demonstrate these effects. In the field, other properties of bryophytes might have stronger impacts, such as mechanical obstruction or alterations in temperature. In laboratory studies, water might not be an adequate extractant for active substances, since all of the chemicals claimed to be allelopathic are lipophilic with potentially longer retention times of the active substances in the soil when compared to water-soluble substances.