Moss and Soil Substrates Interact with Moisture Level to Influence Germination by Three Wetland Tree Species

Abstract

To assess germination success in different microsites of a forested wetland environment, seeds of three common western New York wetland tree species, Acer x freemanii, Fraxinus pennsylvanica, and Ulmus americana, were sown into flats in the greenhouse with three substrates (mosses Hypnum imponens or Thuidium delicatulum or bare soil) and three hydrological conditions (wet, moist, or dry) in a factorial design. For the three species both treatment regimes and the interaction were highly significant, except for Acer, in which the substrate regime was not significant. Fraxinus germination had the highest tolerance for wet conditions and lowest for dry conditions followed by Acer and then Ulmus. Significant interactions showed that the effect of hydrological regime on germination is influenced by substrate type. Moss decreased germination under drier conditions and increased germination under wet conditions by lifting the seeds away from the soil and creating drier conditions than on bare soil. It is also possible that interspecific competition for moisture played a role in decreasing germination under dry conditions. By influencing the regeneration niche for three major tree species of swamps in the northeastern United States, the bryophyte layer plays an important role in determining community composition.

Bryophyte abundance, composition and importance to woody plant recruitment in natural and restoration forests

“…Where studied, the importance of bryophytes to seedling germination has been shown to vary across habitat type, climatic conditions, and study system. Bryophytes can provide positive benefits to native plant recruitment through a variety of mechanisms including regulating moisture loss from soil, harboring beneficial mycorrhizae and providing grass-free microsites for germination (During and Van Tooren, 1990; T Staunch et al, 2012). Conversely, seeds may get caught in bryophyte mats leading to germination but soon die due to the lack of connectivity with soil substrate (Soudzilovskaia et al, 2011;Staunch et al, 2012).…”

“…Bryophytes can provide positive benefits to native plant recruitment through a variety of mechanisms including regulating moisture loss from soil, harboring beneficial mycorrhizae and providing grass-free microsites for germination (During and Van Tooren, 1990; T Staunch et al, 2012). Conversely, seeds may get caught in bryophyte mats leading to germination but soon die due to the lack of connectivity with soil substrate (Soudzilovskaia et al, 2011;Staunch et al, 2012). In temperate forests in Sweden, Picea abies seedling establishment was enhanced by elevated microsites of Sphagnum and Pleurozium (moss) on logs although some seedlings were overgrown by the mosses (Hörnberg et al, 1997).…”

Enhancing Urban Sustainability through Green Roofs: A Thermal Performance Evaluation in Dubai

“…The amount of water that bryophytes can absorb varies greatly depending on the type, but it is generally known that they can absorb 50 -2,000% of their dry weight in water (Salameh et al, 2023). Moss dried by sunlight on a clear day has a moisture level of about 5% and can survive in a dry state at temperatures as low as -196°C and as high as 100°C for a certain period (Staunch et al, 2012;Rousk et al, 2014). Due to their high cation substitution capacity, mosses can even absorb low concentrations of nutrients (Cruz de Carvalho et al, 2012).…”

Plant–plant interactions change during succession on nurse logs in a northern temperate rainforest

“…As the community develops, the amelioration of disturbance and stress by the physical presence of plants (e.g., stabilizing slopes, herbivory protection, microclimate, providing substrate, nutrients, and water) results in competitive interactions becoming more important over time as plants can put more of their energy toward growth and reproduction (Brooker & Callaghan, 1998; Egler, 1954; Ricklefs, 1977; Walker & Chapin, 1987; but see Maestre et al., 2005). While vascular plants have largely been the focus of plant–plant interaction research, bryophytes can have facilitative or competitive interactions with vascular plants depending on multiple abiotic and biotic factors (Doxford et al., 2013; Gornall et al., 2011; Gough, 2006; Rehm et al., 2019; Sedia & Ehrenfeld, 2003; Soudzilovskaia et al., 2011; Staunch et al., 2012). In locations where bryophytes dominate the ground cover, such as in the arctic and boreal forest, bryophytes can structure the composition of vascular plant communities as they are often more tolerant of the stressful conditions than the vascular plants that grow among them (Gavini et al., 2019; Gornall et al., 2011; Gough, 2006).…”