The branch of botany devoted to the scientific study of bryophytes is called bryology. Bryophytes are often considered a paraphyletic group of non-vascular plants with roughly 20,000 species. There are 3 groups of bryophytes: mosses (Bryophyta), liverworts (Marchantiophyta) and hornworts (Anthocerotophyta). Hornworts are not represented in the Arctic; however, liverworts and mosses are commonly distributed. They are often limited in size due to their lack of vascular tissue and prefer moist environments, however some species have adapted to live in drier environments. Bryophytes lack flowers and seeds. They reproduce via spores that are located inside reproductive structures (gametangia and sporangia).
Although bryophytes are considered simple in structure and they are the most primitive plant group, they are highly successful from an evolutionary point of view. They are small but highly successful at establishment and survival in majority of ecosystems worldwide. Bryophytes are found in numerous environments that drastically vary in temperature, latitude, salinity levels, water availability and exposure to the elements. Some bryophyte species are specifically adapted to specific micro-environments and can be used as environmental and ecological indicators as they react to slight changes to their environmental conditions.
Due to bryophytes ability to tolerate a wide range of environmental conditions, withstand desiccation, water retention capabilities, adjust their net assimilation rate with temperature fluxes and have high phenotypic plasticity, they are a usually the first plants to colonise newly exposed ground.
Habitats of bryophyte-rich vegetation, such as peatland and moss tundra, are some of the globe’s largest carbon reservoirs and can be found from arctic to temperate zones. Their overall contribution to vegetation productivity becomes more important in Arctic ecosystems, as their relative cover and diversity increases compared to vascular plants. Bryophytes play a key ecological role as they are an integral component of arctic vegetation cover, abundance and diversity. Due to their insulating properties, bryophytes are important to maintain permafrost.
A warming climate is altering ecosystem composition. Loss of bryophyte biodiversity and abundance is at risk due to the loss of habitat, hydrological changes and competition for habitat from vascular plants due to changing environmental parameters.