Desiccation Avoidance and Hummock Formation Traits of rich fen Bryophytes

The aim of this study was to understand the variation in traits relevant for desiccation avoidance among bryophyte species dominant in rich fens and to assess whether these traits explain the formation of a hummock-hollow gradient within peatlands. In samples of 10 species (Aulacomnium palustre, Calliergonella cuspidata, Climacium dendroides, Hamatocaulis vernicosus, Helodium blandowii, Marchantia polymorpha, Plagiomnium ellipticum, Sphagnum teres, S. warnstorfii, Tomentypnum nitens) collected in rich fens of NE Poland, we calculated: canopy bulk density of wet (CDW) and dry (CDD) colonies, maximum water content of bryophyte colonies (WCmax), desiccation rate (K), shoot area index (SAI), canopy dry mass per surface-projected area (CMA), and specific leaf area of a whole living bryophyte part (SLA). The hummock-forming frequency was quantified for each species in the field. Sphagna had the highest WCmax, SAI and CDW, T. nitens and C. dendroides had the lowest WCmax and SLA, P. ellipticum had the highest K, the lowest CMA and CDD. Hummock-forming frequency was positively correlated with CMA and generally negatively related to K, with exception of H. vernicosus showing a high water-retaining ability (low K) despite a hollow or lawn form of growth.

Automated summary

The aim of this study was to investigate the variation in desiccation avoidance traits among dominant bryophyte species in rich fens and determine their role in the formation of a hummock-hollow gradient. Ten species were sampled, and various traits related to desiccation avoidance were measured. The frequency of hummock formation was positively correlated with certain traits such as canopy dry mass per surface-projected area and negatively correlated with desiccation rate, except for one species with high water-retaining ability despite its growth form.