December 11, 2023

Mosses are one of the most common and underrated plants on earth. A large new study is finally giving moss the recognition it deserves, highlighting its importance in maintaining the planet’s ecosystems and its potential to reduce its carbon footprint.

Moss is found everywhere, from deserts to arctic regions. Despite their ubiquity, mosses are often overlooked in favor of vascular plants, whose roles in improving soils and maintaining plant diversity and ecosystems have been intensively studied.

Vascular plants have both lignified (wood-like) tissues that transport water and minerals throughout the plant, and non-lignified tissues that aid in photosynthesis. In contrast, mosses are non-vascular plants that absorb water and nutrients through their surfaces. Their roots are also different, with growths called rhizomes that anchor them to the soil surface.

As the name suggests, soil moss grows on the surface of the soil. They are also one of the most widely distributed land plants, but little research has been done on how they affect ecosystems. Now, the most comprehensive global field study of moss, led by researchers at the University of New South Wales in Sydney, has examined soil moss in its natural habitat to determine its importance to the planet.

“We were initially interested in how natural systems of undisturbed native vegetation differ from man-made systems such as parks and gardens — our green spaces,” said lead and corresponding author David Eldridge of the study. “So, for this study, we wanted to understand mosses in more detail and what they actually do in providing essential services to the environment.”

The researchers collected samples of mosses growing on soil in more than 123 ecosystems on Earth, ranging from dense rainforests to deserts to icy landscapes. They found that mosses cover an incredible 3.6 million square miles (9.4 million square kilometers) of Earth, nearly the size of Canada or China.

The researchers found that soil moss benefits the soil and neighboring plants in 24 ways, including maintaining soil biodiversity, nutrient cycling, decomposition of organic matter, maintaining microbial populations and controlling soil pathogens.

“We looked at what happened in moss-dominated soils and what happened in soils without moss,” Eldridge said. “We were surprised to find that mosses were doing all these amazing things.”

In addition, the researchers found that mosses are critical for controlling climate-changing carbon dioxide. Globally, soil moss has the potential to absorb 7.08 billion metric tons (6.43 billion tons) of carbon dioxide from the atmosphere compared to soil without moss, they said.

“So you’ve got all the global emissions from land use change, like grazing, devegetation and agriculture-related activities — we think mosses absorb six times more carbon dioxide, so it’s not one-for-one, it’s good six Times,” Eldridge said.

Based on their findings, the researchers urge people not to overlook the benefits of moss and to think twice before removing moss from their gardens.

“People think that if moss is growing on the soil, it means the soil is sterile or problematic,” Eldridge said. “But you know, in terms of the chemistry of the soil, it’s actually doing great things like adding more carbon and nitrogen and being a major stabilizer when it’s disturbed a lot.”

The researchers intend to continue their research to see if moss can rejuvenate soil in urban environments as it can in natural areas.

“We’re also keen to develop strategies for reintroducing moss into degraded soils to speed up the regeneration process,” Eldridge said. “Mosses may well provide the perfect tool to kick-start soil restoration in severely degraded urban and natural areas.”

The study was published in the journal Natural Geoscience.

source: UNSW Sydney