New Research Challenges How Natural England Assesses Blanket Bogs

✅ KEY TAKEAWAY: Environment Agency-backed research shows that blanket bog vegetation reflects underlying water supply - rather than vegetation management history - meaning current assessments risk misclassifying naturally drier, heather-dominated bogs as degraded and setting unrealistic restoration targets based on a one-size-fits-all approach.

Research supported by the Environment Agency suggests that Natural England's approach to assessing blanket bog condition may be fundamentally flawed.

The findings, presented at the IUCN UK Peatland Programme Conference in Londonderry, show that blanket bogs are far more varied than current assessment methods assume - and that vegetation alone is not a reliable indicator of whether a bog is healthy or degraded.

The work was presented by consultant ecologist Ros Tratt of Sheffield Wetland Ecologists in a dedicated Ecohydrology Session at the conference. It builds on a multi-phase research project commissioned by the Environment Agency in partnership with Natural England, Natural Resources Wales, SEPA, and NatureScot.

The implications for how England's upland peatlands are classified, managed, and restored are significant.

Not All Blanket Bogs Are the Same

At the heart of the research is a straightforward but important finding. The wetness of a blanket bog - and therefore the vegetation it supports - depends largely on where its water comes from.

That, in turn, is shaped by the hidden topography beneath the peat. The surface may look similar across a wide moorland landscape, but what lies underneath fundamentally determines how water moves through the system.

The research identifies two broad types of blanket bog:

Ombrogenous "leaky slope" bogs are found on hillsides. They receive water only from rainfall, which drains through and off the slope. These bogs are naturally drier and are typically dominated by heather and other dwarf shrubs or grasses. This is their natural condition - not a sign of damage or degradation.

Topogenous "soup bowl" bogs sit in depressions or troughs that collect additional water from surrounding flow paths. They are naturally much wetter and support much more Sphagnum moss. Their lush, waterlogged appearance reflects their water supply, not a lack of vegetation management.

The problem arises when both types are assessed against the same benchmark.

Why Current Assessments Get It Wrong

Natural England uses the National Vegetation Classification (NVC) and the presence or absence and abundance of key plant species to assess whether blanket bogs are in good or poor condition. Bogs rich in Sphagnum moss tend to be classified as "active" or "intact." Bogs dominated by heather tend to be labelled "degraded" or "modified."

But the research presented by Tratt and colleagues shows that vegetation composition often reflects the underlying ecohydrology - the interaction between water supply and ecology - rather than management history or human-caused degradation. A heather-dominated hill slope bog may be in perfectly natural condition for its topographic setting.

Classifying it as “degraded” because it lacks Sphagnum moss misreads the ecology.

Equally, a Sphagnum-rich soup bowl area classified as "intact" may simply be much wetter because of where it sits in the landscape. Its vegetation tells us about water supply, not ecological quality relative to the drier bogs around it.

In short, the current system risks confusing natural variation with degradation.

The Moor House Example

The research highlights a well-known upland site that illustrates the issue clearly. At Moor House in the North Pennines, the "valley bog" is a topogenous percolating trough bog. It receives additional water from surrounding flow paths, making it naturally wetter with more Sphagnum and less heather.

Crucially, this valley bog is not comparable to the adjacent hill blanket bogs above Trout Beck. Those include the site of the long-running Hard Hill burning experiments. They are true ombrogenous sloping blanket bogs - naturally drier and much more heather-dominated. That is their natural state, shaped by how water moves through the landscape.

Using the wetter valley bog as a reference point for what the drier slope bogs should look like is misleading. Yet under current assessment methods, the difference in vegetation could lead to the slope bogs being classified as degraded simply because they do not resemble their wetter neighbour.

Wet Patches Do Not Define the Whole Bog

The research also addresses a common source of confusion. Soup-bowl depressions frequently occur within larger hill slope bogs, creating localised patches of wetter ground with more Sphagnum. These patches can give a misleading impression of what the surrounding landscape could support.

The presence of a naturally wet hollow within a drier slope bog does not mean the entire bog could - or should - look the same. The water supply conditions that sustain the wet patch simply do not exist across the wider hillside. Setting restoration targets based on these localised features risks pursuing outcomes that the landscape cannot deliver.

A More Nuanced Classification Is Needed

The researchers propose five additional sub-categories for blanket bogs to reflect these ecohydrological differences. The aim is to move beyond a single "blanket bog" category towards a classification system that accounts for how water supply varies across the landscape.

This matters for three practical reasons. First, habitat condition assessments would become more accurate, distinguishing natural variation from genuine degradation. 

Second, restoration targets could be set realistically, based on what each site can actually achieve given its water supply. 

Third, resources could be directed where they will make a real difference rather than being spent trying to make naturally drier bogs wetter than they can sustain.

The summary of the presentation is clear: a blanket approach to blanket bog does not work.

A Perspective from the Moorland

For land managers across England's uplands, these findings will come as no surprise. Many have long argued that blanket bog assessments do not reflect what they observe on the ground - that moorland dominated by heather is routinely labelled degraded when it is, in fact, functioning naturally for its setting.

This research, supported by the statutory agencies' own funding, now provides the scientific evidence to support that view. It also highlights an issue the presentation did not address: the role of natural erosion in old blanket bogs on slopes.

Peat erosion and subsequent reformation is a well-documented natural cycle in upland landscapes, distinct from management-related degradation. Any comprehensive reassessment of bog condition should account for this too.

It is worth noting the institutional context. This research was commissioned by the Environment Agency in partnership with Natural England itself. The findings were presented at the IUCN UK Peatland Programme's own conference. The science is not contested - it is emerging from within the sector. The question now is whether assessment and restoration policy will catch up.

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