Is an infrequent moss species a weaker competitor? Experiment with three fen species

Overexploitation of mires leads to habitat degradation for many species, and the greatest impact is on species with specific demands or restricted distribution. Three fen species – with overlapping ecological demands, but different distribution frequency – were included in the study, to elucidate whether a less common species could be a weaker competitor under certain ecological conditions compared to other moss species inhabiting the same habitat. We grew the species under conditions that imitated changes in fen communities caused by human activities: water level drop, temperature rise, and shade increase. The species were grown as monocultures and as mixtures in distilled water, to exclude the influence of minerals and nutrients. Although all the species reacted to the different environmental conditions in a similar way, they grew better in monocultures. The shoot elongation of Hamatocaulis vernicosus, a less frequent species, even exceeded that of the two more common species included in the study: Calliergonella cuspidata and Scorpidium cossonii. Pairwise comparisons of shoot elongation showed the success of H. vernicosus. Our results proved that H. vernicosus is not a weaker competitor than other fen mosses in nutrient‐poor conditions, and can defeat the others in cool and flooded conditions. Restoration and conservation of such fen habitats is important to protect the populations of this species.