Phosphorus concentration and pH in decaying wood affect establishment of the red-listed moss Buxbaumia viridis

Abstract

Many red-listed species grow on decaying wood in the boreal forest, and their persistence depends on dispersal to new patches. To investigate whether substrate quality could affect establishment and distribution of the red-listed moss Buxbaumia viridis (DC) Moug. & Nestl., cultivation experiments as well as a field investigation of wood quality were performed. Spore germination was negatively affected by low pH and phosphorus (P) concentration in cultivation media, while nitrogen (N) concentration did not significantly affect germination. Results from the experiments were supported by the field investigation, where the probability of sporophyte occurrence increased with increasing pH. In addition, the interaction between substrate type (wood or humus) and P was significant. Occurrence of sporophytes was not significantly affected by N concentration in the wood. The results from the cultivation experiments and the field study imply that the safe site for germination and establishment of Buxbaumia viridis is either a substrate with continuously high moisture or a substrate with lower moisture but with increased pH and (or) P content, attained, e.g., by throughfall and litterfall from deciduous trees, and that non-optimal pH, P, and moisture conditions could restrict establishment and distribution of the species.Key words: bryophyte, decaying wood, germination, protonema, safe site, substrate quality.