Blanket bogs

Context

Bogs are wetlands that support vegetation that is usually peat-forming and which receive mineral nutrients principally from precipitation rather than ground water.  This is referred to as ombrotrophic (rain-fed) mire.  Two major bog types are identified, namely raised bog and blanket bog.  These two types are, for the most part, fairly distinctive, but they are extremes of what can be considered an ecological continuum and intermediate (or mixed) types occur.
 
The vegetation of bogs which have not been modified by surface drying and aeration or heavy grazing is dominated by acidophilous species, such as bog-mosses Sphagnum spp., cottongrass Eriophorum spp. and cross-leaved heath Erica tetralix.  The water-table on these types of bogs is usually at or just below the surface.  The bog feature types discussed here are mainly found in upland areas though blanket bog types do occur in some lowland areas.  The Natura 2000 feature 'depressions on peat substrates (Rhynchosporion)' is included here where it occurs as blanket bog. 
 
SSSIs can be notified if they qualify under criteria outlined in Section 5 of Chapter 8 Bogs of the Guidelines for Selection of Biological SSSIs.  In Northern Ireland, ASSIs are selected on a very similar basis – the Guidelines for the Selection of Biological ASSIs in Northern Ireland is an addendum to the SSSI guidelines rather than an alternative.
 

Summary statistics

  SAC A/SSSI Total
Favourable condition 45% 58% 54%
Main monitoring coverage E, S, NI E, S, NI  
Reported assessments 66 156 222
Completeness of assessments 65% unknown  
Distribution of features     UK
 

Number of assessments reported by country and site type

Country SAC SSSI/ASSI
England 10 56
Scotland 47 93
Wales 4 0
Northern Ireland 5 7
United Kingdom 66 156
 

Natura features

List of Natura 2000 interest features within this reporting category

Interest feature name  
Formal name Informal name No. of assessments reported Total no. of features % assessed
Blanket bogs Blanket bog 55 78 71%
Depressions on peat substrates of the Rhynchosporion Depressions on peat substrates 11 22 50%
Transition mires and quaking bogs Very wet mires often identified by an unstable 'quaking' surface 0 2 0%
 
Natura 2000 comprises Special Protection Areas (under the Birds Directive) and Special Areas for Conservation (under the Habitats and Species Directive). The list presented here includes all of the qualifying interest features under these Directives, and shows the proportion of these features for which a condition assessment has been made.
 

SSSI features

List of SSSI and ASSI interest features in this reporting category

Interest feature name  
Formal name Informal name No. of assessments reported
Blanket bogs Transition mires and quaking bogs 1
Blanket bogs Blanket bog 93
Blanket bogs Active blanket bogs 1
Bogs Bogs 56
Intermediate blanket bog Intermediate blanket bog 3
Saddle mire Saddle mire 2
 
This list has not been fully standardised at a UK level yet. It is intended to show the principal constituent "feature types" for this reporting category.
 

Maps - distribution

UK distibution of reported interest features

Distribution of reported interest features.

Map showing the locations of the 10km squares in which at least one condition assessment has been reported. It does not show features that have not yet been assessed.

 

Maps - Natura

Distribution of SAC features showing assessments of favourability Condition of SAC features, with those currently reported as unfavourable-recovering shown as favourable
Current condition of SAC features
Distribution of SAC features showing assessments of favourability (where unfavourable-recovering is counted as unfavourable).
Condition of SAC features, with those currently reported as unfavourable-recovering shown as favourable
The implication of the unfavourable-recovering condition assessments is that at some point in the future these features should become favourable. This map shows the effect of that recovery by counting the favourable and unfavourable-recovering assessments together.

 

IMPORTANT NOTE: we do not have information on the timescale of the predicted recovery, which may be influenced by many past, natural and human related factors. A sustained sympathetic management regime is more likely to result in favourable condition being attained.

Key: Proportion of assessed features on 10km squares that are favourable:

Natura map legend - Key: proportion of assessed features on 10km squares that are favourable

 

Details of how these maps were produced

 

Maps - SSSI

Current condition of SSSI/ASSI features Condition of SSSI/ASSI features, with those currently reported as unfavourable-recovering shown as favourable
Current condition of SSSI/ASSI features
Distribution of SSSI/ASSI features showing assessments of favourability (where unfavourable-recovering is counted as unfavourable).
Condition of SSSI/ASSI features, with those currently reported as unfavourable-recovering shown as favourable
The implication of the unfavourable-recovering condition assessments is that at some point in the future these features should become favourable. This map shows the effect of that recovery by counting the favourable and unfavourable-recovering assessments together.

 

IMPORTANT NOTE: we do not have information on the timescale of the predicted recovery, which may be influenced by many past, natural and human related factors. A sustained sympathetic management regime is more likely to result in favourable condition being attained.

Key: Proportion of assessed features on 10km squares that are favourable:

SSSI map legend - Proportion of assessed features on 10km squares that are favourable

 

Details of how these maps were produced

 

Condition summary

Reporting category condition summary on Natura 2000 sites and SSSI

This lists the 10 different condition assessments and presents a bar chart showing the number of features within the SSSI series and the Natura 2000 series (either SPA for bird features or SAC for features other than birds). Note that for Natura 2000 we are able to estimate the number of features that have not been assessed during the 6 year reporting period - we are unable to do this for SSSI/ASSI because we do not have an overall list of notified interest features for these designations.

 

NB favourable unclassified and unfavourable unclassified have been used in this first six year cycle to get around difficulties in identifying trends in condition as common standards monitoring is implemented. It is expected that these categories will not be used for subsequent assessments of a feature.

 

Condition assessment - Natura 2000 features

The number and proportion of assessments for Natura 2000 (SAC and SPA) interest features falling into each of the condition categories
The number and proportion of assessments for Natura 2000 (SAC and SPA) interest features falling into each of the condition categories. Note that the �unfavourable� category includes all reports of unfavourable condition except �unfavourable recovering� which is shown as a separate segment.
 

Condition assessment - SSSI features

The number and proportion of assessments for SSSI/ASSI interest features falling into each of the condition categories
The number and proportion of assessments for SSSI/ASSI interest features falling into each of the condition categories. Note that the �unfavourable� category includes all reports of unfavourable condition except �unfavourable recovering� which is shown as a separate segment.
 

Adverse activities

The number of interest features where an activity has been reported as being implicated in the "unfavourable" condition of a feature
The number of interest features where an activity has been reported as being implicated in the "unfavourable" condition of a feature. More than one adverse activity may be reported for each feature.
 

Management measures

The measures summary bar chart lists the management measures relevant to the reporting category
For each "measure" the chart shows the number of interest features where that measure has been taken on a site to improve or maintain the condition of an interest feature. More than one measure may be reported for each feature assessed.
 

Interpretation

54% of blanket bog features reported are in favourable condition.  This is just below the average for all features combined, and above the averages for terrestrial habitats and all habitats.  58% of the A/SSSI features and 45% of SAC features reported are in favourable condition.  15% of A/SSSI and 14% of SAC features reported are unfavourable-recovering. 
 
The reported activities that have had the greatest impact contributing to unfavourable condition on blanket bog features are over-grazing, and burning, and, to a slightly lesser degree, water (hydrology) management, and a lack of conservation management being in place. Over-grazing leads to loss of vegetation structure and the failure of more palatable or vulnerable species to reproduce and maintain themselves. It can also lead to the loss of plant species and associated fauna, and the spread of rank, unpalatable plant species. In extreme cases, very heavy grazing and trampling can lead to exposure of bare peat and erosion. There is, therefore, a need for grazing to be undertaken at the right time and with the right intensity. There is also a need for correct burning practices and to reinstate natural hydrology by blocking grips (lines cut through moorland for drainage purposes). The problem of gripping on blanket bogs is a major cause of unfavourable condition that has not yet been fully reported on, particularly in England. It is also possible that, although not identified as an 'activity', trampling damage is very often associated with over-grazing and can make recovery times longer. The reporting of measures taken to address unfavourable condition indicates that management agreements/schemes and agri-environment schemes are in place on many sites. However, it is not yet known how long it may take to return blanket bog features to favourable condition.