A review of frameworks for using bryophytes as indicators of climate change with special emphasis on Sri Lankan bryoflora

The tropical island of Sri Lanka, with a land area of 65,610 km² and 1340 km of coastline, is highly vulnerable to impacts of climate change, with detrimental effects on agriculture, water resources, human health, coastal zones, infrastructure, industry, and biodiversity. A general increase in temperature and precipitation patterns, rising sea levels, and increase in weather-related natural disasters, such as floods and droughts, have been traced over the years. Bryophytes (liverworts, mosses, hornworts) occupy a pivotal position in the land plant evolution and form a unique part of the vegetation. Many taxa of bryophytes exhibit observable, distinct adaptations in response to changes in environmental conditions quickly. Bryophytes can be used to monitor climate change in two ways; (i) presence or absence in the ecosystem and (ii) changes in morphology and physiology that can be used for monitoring. Sri Lanka has a rich bryophyte flora consisting of 575 species of mosses, 338 species of liverworts, and 07 species of hornworts. It is estimated that 11% of mosses are endemic; there are no endemic thalloid liverworts or hornworts found in Sri Lanka, and the endemicity of leafy liverworts is yet to be investigated. The taxonomic status of endemic taxa and the biogeographic affinities of many taxa remain unexplored. Further, the potential use of bryophytes as indicators of climate change in Sri Lanka has not yet been investigated. This paper compiles the information on morphological and physiological responses of bryophytes to elevated temperature, increase in greenhouse gases, increased ultraviolet-B (UV-B) radiation, and fluctuations in humidity. In the light of this gathered global knowledge, possible species of bryophytes to be used in assessing and predicting climate change and developing a climate change model in Sri Lanka are proposed. Asian bryophytes, in general, have poorly been represented in climate change literature. We believe that this knowledge will form the foundation for future research focused on climate change mitigation in other tropical and Asian countries.