Epiphytes Explained: The role of Lichens and Mosses in our Temperate Rainforests

Written by: Alejandra Hart

Lichens and Mosses on gate in Devon, credit: WTML/Paul Glendell 

Temperate rainforests are among the most ecologically diverse ecosystems in the world. Although 90% of the UK’s temperate rainforests have been lost, these rainforests remain a stronghold for a remarkable diversity of lichens and mosses. In this blog, we will explore the essential roles these species play in maintaining the health and balance of temperate rainforests. 

Lichens:  

Lichens are fascinating organisms that form a symbiotic relationship between fungi and algae. They thrive in the unique environment of temperate rainforests, where high humidity and the abundance of organic matter create ideal conditions for their growth. 

• Biodiversity indicators: Lichens are sensitive to air pollution and climate changes, so their presence (or absence) is a natural indicator of air quality and the overall health of a temperate rainforest. 

• Rainforest engineers and soil formation: By breaking down rocks and decaying wood, lichens contribute to soil development, creating a foundation for other plants to grow. 

Tree bark covered in a variety of lichens. Credit Bull + Wolfe. 

Mosses: 

Mosses are small, non-vascular plants that thrive in the moisture-rich conditions of temperate rainforests: 

• Water retention: Mosses act like sponges, absorbing and retaining moisture to help maintain humidity levels crucial for the survival of rainforest species. 

• Soil stability: As mosses grow, they help form a stable, nutrient-rich substrate that supports the growth of other plants.   

• Microhabitats for wildlife: Moss-covered surfaces provide shelter and food for insects, amphibians, and other rainforest species. 

 Leucobryum glaucum grows in the rainforest zone. Credit: Bull + Wolfe 

The South West’s temperate rainforests are home to an incredible variety of lichens and mosses. We have the Lungwort Lichen, which was once believed to cure lung disease due to its resemblance to a human lung. Another fascinating species is Usnea Articulata, also known as ‘string of sausages’, which forms long, segmented strands that drape from tree branches, thriving in the rainforest’s humid conditions. When it comes to mosses, one to look out for is the Hookeria Lucens, it stands out for its translucent green colour, and it is a key rainforest indicator. 

Lungwort Lichen, which was once believed to cure lung disease due to its resemblance to a human lung. Credit: Bull + Wolfe 

Usnea Articulata, also known as ‘string of sausages’. Credit: Bull + Wolfe 

 Hookeria Lucens is a key rainforest indicator species. Credit: Pete Callahan 

Fun facts about lichens and mosses: 

• Did you know there are over 2000 species of lichen in the UK? That is more than most countries in Europe! 

• Lichens are space survivors! In a 2005 experiment conducted by the European Space Agency (ESA), two species of lichen - Rhizocarpon geographicum and Xanthoria elegans - were exposed to the vacuum of space, extreme temperatures, and intense ultraviolet radiation for nearly 15 days, and lived to tell the tale! 

• Mosses can hold water up to 20 times their own weight! 

Lichens and mosses can often go unnoticed, but they are vital to temperate rainforests. As we continue to lose valuable rainforest habitat, protecting and appreciating these remarkable species becomes even more crucial. By recognising their significance, we can contribute to the conservation of the UK’s remaining temperate rainforests, ensuring they thrive for generations to come.  

Grey Park Wood mossy banks. Credit: WTML/Adam Burton 

We hope this blog has inspired you to take a closer look at the rainforest floor (and trees!) next time you’re out exploring. Please keep coming back to this site to find out more about our wonderful temperate rainforests! 

Rainforest Recovery is the South West strand of The Rainforest Restoration Project. It is being led by the Woodland Trust in partnership with Plantlife. This project is funded as part of the Government's Species Survival Fund. The fund was developed by Defra and its Arm's-Length Bodies. It is being delivered on behalf of Defra by The National Lottery Heritage Fund.