Peatlands are unique wetland ecosystems characterized by the accumulation of partially decayed organic matter, known as peat. These waterlogged environments slow decomposition, allowing dead plant material to build up over thousands of years. Found across various climates, from boreal to tropical regions, peatlands represent a distinctive and delicate part of the Earth’s natural systems. Peatland restoration involves efforts to return these degraded landscapes to their natural, wet state, which is a significant environmental undertaking.
Why Peatlands Matter
Healthy peatlands serve as the largest natural terrestrial carbon store on Earth. They hold more carbon than all other vegetation types globally, with peat soils containing over 600 gigatonnes of carbon, representing up to 44% of all soil carbon. This capacity stems from waterlogged conditions that prevent plant material from fully decomposing, locking carbon away from the atmosphere. These ecosystems also support a wide array of specialized plant and animal species, many of which are adapted to their nutrient-poor, acidic, and wet conditions.
Beyond carbon sequestration and biodiversity, peatlands play a significant role in water regulation. They act as natural filters, improving water quality by trapping sediments and absorbing certain nutrients and pollutants. Peatlands also help regulate water flow, reducing the risk of floods by slowing down water runoff and maintaining base flow in rivers during dry periods. Approximately 70% of the UK’s drinking water, for example, is sourced from peatlands, highlighting their importance for clean water supplies.
How Peatlands Become Degraded
Peatlands degrade primarily due to human activities. Drainage for agriculture, forestry, or urban development is a major cause, as it lowers the water table and exposes peat to oxygen. This exposure causes stored carbon to oxidize, releasing significant carbon dioxide into the atmosphere. In some regions, up to 80% of peatlands have been damaged, substantially losing their carbon storage function.
Peat extraction for fuel or horticulture also degrades peatlands. This directly removes peat, destroying habitat and releasing stored carbon. Wildfires pose another threat, especially to dried-out peatlands, where they can burn underground for extended periods and release massive greenhouse gases. For instance, fires in Indonesian peat swamp forests in 2015 emitted nearly 16 million tonnes of CO2 per day, exceeding the daily emissions of the entire United States economy.
Strategies for Peatland Restoration
Restoring degraded peatlands primarily focuses on re-establishing their natural waterlogged conditions, a process known as rewetting.
Rewetting
This involves blocking drainage ditches, often using peat dams or other barriers, to raise the water table to near the surface. Removing non-native trees, such as conifers, is also part of rewetting efforts, as these trees draw water away from the peat, exacerbating dryness.
Revegetation
Revegetation is another approach, aiming to reintroduce peat-forming plants, particularly Sphagnum mosses, which are fundamental to peat accumulation. This involves spreading heather brash rich in mosses and seeds or directly transplanting Sphagnum propagules onto bare peat surfaces. Mulching with appropriate plant material can also provide immediate cover, stabilize peat, and create microclimates conducive to new plant growth. These methods help to halt further peat loss due to wind, water erosion, and oxidation.
Surface Reprofiling
Surface reprofiling involves reshaping the land to create conditions suitable for water retention and plant establishment. This can include re-sloping steep gully sides or eroding peat hags to shallower gradients (typically less than 35 degrees) to prevent further erosion and facilitate revegetation. Creating basins or flat terraces can also help retain water on the surface, supporting bog vegetation re-establishment. Careful planning is needed to avoid compacting peat with heavy machinery, which could damage its delicate structure.
Benefits of Restored Peatlands
Peatland restoration yields multiple positive environmental outcomes, starting with climate change mitigation. Rewetted peatlands cease greenhouse gas emissions and resume their function as carbon sinks, drawing carbon dioxide from the atmosphere. Although full recovery can take centuries, restoration immediately reduces carbon losses. Studies show bringing the water table to within 30 centimeters of the surface can reduce decomposition, lessening warming by the equivalent of at least 3 tonnes of carbon dioxide per hectare per year.
Restored peatlands also enhance biodiversity, as waterlogged conditions allow specialized native plant and animal species to re-establish. This includes the recovery of unique bog pools, providing habitat for aquatic invertebrates and amphibians. The re-establishment of a dense Sphagnum layer improves water quality by filtering sediments and pollutants from water flowing through the peatland.
Restored peatlands also contribute to flood alleviation. By slowing water flow, especially during heavy rainfall, healthy peatlands reduce peak flood levels downstream, protecting communities and infrastructure. This water regulation capacity, combined with improved water quality and carbon sequestration, underscores the multifaceted environmental advantages of peatland restoration.