Stress tolerance of rare and common moss species in relation to their occupied environments and asexual dispersal potential

Abstract

Summary1 Species rarity in mosses may be linked to narrow physiological tolerance and habitat specificity of established colonies and gametophyte fragments (i.e. fragments of stem apices). Stress tolerance and habitat light and moisture were compared for three rare and three common moss species. 2 Observed habitat specificity was more likely to correspond to physiology in the common species. In particular, one common species, Mnium spinulosum , was limited by intolerance of high light conditions and is characteristic of deeply shaded conifer stands, while another, Bryum pseudotriquetrum , lacked desiccation tolerance and is typical of moist areas such as stream banks. However, the rare species, Mielichhoferia macrocarpa , which occurred in the darkest and wettest sites was not intolerant of high light or desiccation. 3 The relationship between desiccation tolerance and habitat moisture (based on a mesic to xeric scale) was less clear than in prior bryophyte studies, suggesting that a more rigorous quantification of habitat moisture is needed. 4 Contrary to predictions, the rare species did not have narrower physiological tolerances than the common species. The match between environment and physiology for common species probably results from their occupation of more of the potentially suitable sites. 5 There may also be selection for broader physiological tolerance in rare species resulting from their greater reliance on asexual reproduction, which might explain their relatively high desiccation tolerance both as colonies and fragments.

Diaspore bank of bryophytes in tropical rain forests: the importance of breeding system, phylum and microhabitat

“…Spores of epiphytic and epixylic species have their viability reduced from around 90% to near zero after 48-240 days and 25-30 days, respectively (Egunyomi 1978;Wiklund and Rydin 2004;Maciel da Silva et al 2009). Apical gametophyte fragments maintain 80% or higher viability after 120 days in the Weld under dry storage (Cleavitt 2002(Cleavitt , 2005. In contrast, spores of Sphagnum could retain high viability (around 70%) after 3 years of burial in peat (Sundberg and Rydin 2000), and desiccated moss tubers can germinate after more than a century (H. During, personal communication).…”

Recolonization potential of bryophyte diaspore banks in harvested boreal mixed-wood forest

“…In contrast, species belonging to the family Mniaceae, which are common beneath closed mixedwood canopies, had reduced germination in the high light cabinet. Mnium spinulosum is intolerant of high light because of physiological limitations; its preferred habitat is shaded coniferous forest (Cleavitt 2002). Brachythecium velutinum is frequently found beneath closed forest canopies (Mills and Macdonald 2005) and was significantly less abundant in the high light cabinet, possibly reflecting a preference for reduced light levels.…”

Effects of storage temperature on the physiological characteristics and vegetative propagation of desiccation-tolerant mosses

“…To date, several moss cultivation experiments have been conducted in which gametophyte fragments are used to establish new colonies in the laboratory and field (Cleavitt, 2002;Jones and Rosentreter, 2006;Xiao et al, 2015). All of these experiments have demonstrated that artificial cultivation can accelerate the succession process of moss crusts.…”