Planting moss helps restore land damaged by oil and gas exploration

In western Canada’s wetlands, a quiet revolution is taking shape. Scientists are bringing mossy peatlands and damaged well pads back to life after decades of oil and gas activity left them altered.

A research team from the University of Waterloo, supported by several Canadian institutions, has tested a new restoration method to revive peatland vegetation on oil well pads.

These pads, once used for drilling, have disrupted the delicate water systems and plant life of boreal fens. Now, the team’s breakthrough shows that true mosses – the core builders of peatlands – can grow again, even on degraded, mineral-rich soils.

How pads disrupted peatland ecosystems

Canada’s boreal peatlands are not just rich in moss – they store massive amounts of carbon and regulate freshwater systems across the country.

However, many of these ecosystems have been disrupted by the construction of over 36,000 hectares of well pads and 100,000 km of access roads.

These pads bury native vegetation under layers of clay and sand, severing their connection to natural hydrology and altering nearby ecosystems.

Traditional restoration techniques often focused on replanting trees or grasses to convert damaged land into forest or grassland.

But such solutions overlook the unique role of peatlands in storing carbon and supporting biodiversity. The new method shifts the focus: it seeks to restore the land to its original, moss-dominated state.

“These results are the first to suggest that the re-establishment of peatland vegetation on full-scale lowered well pads is possible,” said Murdoch McKinnon, PhD candidate in the Faculty of Environment.

“Well pads bury all of the native peatland vegetation under clay or sand, negatively impacting the ability of the peatland to sequester carbon and also reducing the availability of habitat for wildlife.”

Moss-based method on well pads

In 2020, researchers implemented this large-scale trial on a decommissioned well pad near Slave Lake, Alberta. The strategy involved partially removing the upper layers of the pad and transplanting native mosses collected from a nearby donor site.

The moss species included true mosses like Aulacomnium palustre, Tomentypnum nitens, and Helodium blandowii – all typical of rich fens. The surface of the pad was reshaped to include low and high microtopographies.

This mimics natural peatland surfaces and helps retain water in dips, which is essential for moss survival. A straw mulch layer was applied to half the plots to slow evaporation and protect the mosses from drying winds.

The approach draws inspiration from a natural process called paludification, where peatlands expand over mineral soils due to consistent water saturation.

By partially removing the well pad surface, the method aimed to replicate conditions that allow early successional peatland vegetation to thrive.

Moss needs steady water to survive

Peatland mosses, unlike vascular plants, lack roots and internal water transport systems. Their health depends entirely on the moisture around them.

In this study, researchers found that mosses thrived when the water table stayed within six centimeters of the surface. These optimal conditions were found mostly along the pad’s edges, which were still hydrologically connected to the surrounding natural peatland.

In contrast, interior zones of the pad experienced rapid drying during the late season. This dryness occurred because those sections lacked direct groundwater input and had poor water retention due to the coarse sandy substrate.

Mosses in these interior zones faced significant risks of desiccation, particularly during the second study year, which was drier than normal.

The team concluded that the restoration method works best when a steady flow of water can reach the transplanted mosses. Otherwise, even with added mulch, the mosses struggled to maintain the hydration needed for photosynthesis and growth.

Dry years limit moss growth

The study ran over two growing seasons. The first season had near-average rainfall, while the second was drier, reflecting potential future climate scenarios.

In the wet year, seven plots on the pad maintained near-surface water tables and showed high potential for moss establishment. In the drier year, only one plot – located at the hydrologically favorable northeast corner – retained adequate moisture.

Drying trends in interior plots suggested that the partial removal technique alone may not suffice under climate stress. Mosses planted in these areas often encountered moisture conditions below their survival threshold.

This highlights the need to improve subsurface hydrological connectivity across the pad, perhaps by altering slope design or installing water flow conduits.

“Preserving peatlands is critical because of the role they play storing and supplying water in the landscape,” said Dr. Richard Petrone, a professor in the Department of Geography and Environmental Management at Waterloo.

“They are also our best choice for nature-based climate change solutions because of the vast amounts of carbon that they store.”

What happens when moss dries out

The risk of moss desiccation became particularly clear in the pad’s interior zones. Researchers measured soil moisture and water potential across different microtopographic levels.

They found that when the water table dropped below 54 cm, mosses – especially those on high ground – entered the desiccation danger zone. Mulching helped slightly in low areas but had limited effect overall.

The straw was often blown off high points by wind, reducing its ability to shield mosses from evaporation. These findings suggest that water table depth has a stronger impact than surface treatments in controlling moss health.

Some moss species can tolerate drying, but growth slows or halts altogether. Rewetting takes time, and extended dry periods can stunt long-term recovery. This makes mosses in interior pad zones especially vulnerable during drought years.

Some mosses thrive on well pads

Not all mosses need the same conditions. Species like Tomentypnum nitens and Aulacomnium palustre can survive across a wide range of moisture levels.

These species may establish even in dry interior areas. However, the long-term success of a diverse peatland community depends on retaining wet microsites and providing favorable conditions across the landscape.

Interestingly, plots near the pad edges also saw some short-term saturation. This may allow submergence-tolerant mosses to dominate.

Researchers noted that while prolonged flooding can reduce photosynthesis, it is less damaging than complete desiccation.

These microtopographic differences might ultimately support greater moss diversity by allowing multiple species to thrive in different niches. But the initial phase is critical. Without stable moisture early on, even hardy mosses can fail to establish.

Beyond moss: Other restoration pathways

In some parts of the pad, especially where water tables dropped sharply, true mosses may not be the best candidates.

These zones could instead support sedges like Carex and Scirpus species, which tolerate fluctuating moisture better. Introducing these plants might kickstart organic matter buildup and improve soil water retention over time.

The idea is not to force every plot to become a moss-dominated peatland. Instead, researchers are exploring mixed strategies tailored to local conditions.

Over decades, sedges could help transform dry mineral soils into suitable environments for future moss colonization.

Peatland restoration requires better tools

The study marks a turning point in how scientists approach restoration on former drilling sites. While the partial removal method shows promise, it works best when combined with other interventions.

Adding organic matter, adjusting terrain slopes, or installing water flow conduits may improve moss survival rates in drier regions. Long-term monitoring remains essential.

The researchers will continue studying how moss communities develop over time and whether introduced species can become self-sustaining. There’s also a need to refine water availability thresholds for different moss types to better guide future efforts.

This work reflects a growing understanding that restoration is not just about replanting vegetation. It’s about re-establishing the physical and hydrological foundations that ecosystems need to thrive.

—–

The full findings of this study are detailed in Hydrologic assessment of mineral substrate suitability for true moss initiation in a boreal peatland undergoing restoration, published in Ecological Engineering.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. 

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–