Other invertebrates

Context

Sites of Special Scientific Interest (SSSIs) can be notified if they include qualifying features under the invertebrate criteria outlined in section 3 of Chapter 17 'Invertebrates' 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. 

 
It is the rarer, more specialised invertebrate species that need particular attention, especially where there is evidence that their macro- or micro-habitat requirements are not represented within the existing SSSI series.  Therefore sites containing the best examples of such features, e.g. micro-habitats such as ancient trees with dead and decaying wood, and large river shingle banks, are candidates for selection as SSSIs.  Habitat mosaics are also of great importance, because many invertebrates live in situations which may be classed as transitions between habitat types or because there is a need for different habitat conditions at different stages of their life history.
 
The strongest populations of the rarer and more threatened invertebrates, which typically have narrow and unusual habitat requirements, should be considered as features for the notification of SSSIs.  Highest priority should be given to Red Data Book (RDB) endangered, vulnerable, rare and endemic species, with species listed as 'out of danger' also remaining important.  Nationally scarce species (and their assemblages), known or estimated in 16-100 10km grid squares in Britain should also be represented.  Regionally scarce species may also be considered as significant for site notification.
 
All species with populations listed in Schedule 5 of the Wildlife and Countryside Act 1981 (as amended 1985) qualify for consideration.  The location supporting the strongest population in Great Britain of a RDB species should be regarded as a candidate site, as well as sites with strong populations of well-recorded RDB groups such as butterflies, macro-moths, grasshoppers and crickets, ground beetles, water beetles and hoverflies.
 
Under Annex II of the EC Habitats Directive, a number of molluscs and arthropods qualify as features for the selection of Special Areas of Conservation (SACs) in the UK, and which fit in the Other invertebrates reporting category.  The molluscs are Geyer's whorl snail Vertigo geyeri, narrow-mouthed whorl snail Vertigo angustior, round-mouthed whorl snail Vertigo genesii, Desmoulin's whorl snail Vertigo moulinsiana, freshwater pearl mussel Margaritifera margaritifera and ramshorn snail Anisus vorticulus.  The arthropods are violet click beetle Limoniscus violaceus, stag beetle Lucanus cervus, white-clawed (or Atlantic stream) crayfish Austropotamobius pallipes and Fisher's estuarine moth Gortyna borelii lunata.
 

Summary statistics

  SAC A/SSSI Total
Favourable condition 12% 72% 62%
Main monitoring coverage E, S, W E, S  
Reported assessments 51 247 298
Completeness of assessments 75% unknown  
Distribution of features     UK
 

Number of assessments reported by country and site type

Country SAC SSSI/ASSI
England 31 107
Scotland 13 138
Wales 4 0
Northern Ireland 3 2
United Kingdom 51 247
 

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
Austropotamobius pallipes White-clawed (or Atlantic stream) crayfish 10 11 91%
Limoniscus violaceus Violet click beetle 3 3 100%
Lucanus cervus Stag beetle 4 5 80%
Margaritifera margaritifera Freshwater pearl mussel 19 26 73%
Vertigo angustior Narrow-mouthed whorl snail 3 4 75%
Vertigo genesii Round-mouthed whorl snail 1 3 33%
Vertigo geyeri Geyer's whorl snail 3 7 43%
Vertigo moulinsiana Desmoulin's whorl snail 8 9 89%
 
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
Agabus brunneus A diving beetle 1
Asilus crabroniformis Hornet robberfly 2
Austropotamobius pallipes White-clawed (or Atlantic stream) crayfish 1
Bolitophagus reticulatus A beetle 1
Cerastoderma lanack Brackish water cockle 1
Eutheia linearis A beetle 1
Gabrius scoticus A beetle 1
Heliophanus dampfi A spider 1
Hirudo medicinalis Medicinal leech 1
Lampronia fuscatella A moth 1
Limoniscus violaceus Violet click beetle 1
Lycia lapponaria Rannoch brindled beauty moth 1
Margaritifera margaritifera Freshwater pearl mussel 6
Nebria nivalis A beetle 1
Nematostella vectensis Starlet sea anemone 1
Oreodytes alpinus A beetle 1
Pancalia schwarzella A moth 1
Pareulype berberata Barberry carpet 1
Phagoteryx brevipennis A caddis fly 1
Siona lineata Black-veined moth 1
Teodoxus fluviatilis A snail 1
Tipula luridirostris A fly 1
Trichoniscoides saeroeensis A woodlouse 1
Tyta luctuosa Four-spotted moth 1
Vertigo alpestris A snail 1
Victorella pavida Trembling sea-mat 1
Xylena exosoleta Sword grass moth 1
Ylodes (Triaenodes) reuteri A caddis fly 1
Zygaena lonicerae jocelynae Burnet moth 1
Zygaena loti Slender Scotch Burnet moth 1
Beetles Beetles 53
Caddis flies Caddis flies 2
Flies Flies 27
Grasshoppers Grasshoppers 1
Invertebrate assemblage Invertebrate assemblage 35
Invertebrate assemblage: brackish marsh: lagoon Invertebrate assemblage: brackish marsh: lagoon 1
Invertebrate assemblage: brackish marsh: upper saltmarsh Invertebrate assemblage: brackish marsh: upper saltmarsh 1
Invertebrate assemblage: dunes Invertebrate assemblage: dunes 1
Invertebrate assemblage: early successional Invertebrate assemblage: early successional 1
Invertebrate assemblage: early successional: dry Invertebrate assemblage: early successional: dry 1
Invertebrate assemblage: early successional: sandy Invertebrate assemblage: early successional: sandy 2
Invertebrate assemblage: early successional: scrub Invertebrate assemblage: early successional: scrub 1
Invertebrate assemblage: fen Invertebrate assemblage: fen 2
Invertebrate assemblage: fen: floodplain Invertebrate assemblage: fen: floodplain 3
Invertebrate assemblage: fen: pools Invertebrate assemblage: fen: pools 4
Invertebrate assemblage: glades and rides Invertebrate assemblage: glades and rides 1
Invertebrate assemblage: glades and rides: scrub Invertebrate assemblage: glades and rides: scrub 2
Invertebrate assemblage: grassland Invertebrate assemblage: grassland 2
Invertebrate assemblage: grassland: calcareous Invertebrate assemblage: grassland: calcareous 5
Invertebrate assemblage: grassland: free-draining Invertebrate assemblage: grassland: free-draining 2
Invertebrate assemblage: grassland: sandy Invertebrate assemblage: grassland: sandy 2
Invertebrate assemblage: grassland: scrub Invertebrate assemblage: grassland: scrub 4
Invertebrate assemblage: headwater: calcareous Invertebrate assemblage: headwater: calcareous 1
Invertebrate assemblage: heathland Invertebrate assemblage: heathland 1
Invertebrate assemblage: heathland: scrub Invertebrate assemblage: heathland: scrub 1
Invertebrate assemblage: heathland: wet Invertebrate assemblage: heathland: wet 1
Invertebrate assemblage: marsh Invertebrate assemblage: marsh 1
Invertebrate assemblage: marsh: detritus pond Invertebrate assemblage: marsh: detritus pond 1
Invertebrate assemblage: marsh: silt pond Invertebrate assemblage: marsh: silt pond 2
Invertebrate assemblage: mature woodland Invertebrate assemblage: mature woodland 1
Invertebrate assemblage: mature woodland: canopy Invertebrate assemblage: mature woodland: canopy 1
Invertebrate assemblage: mature woodland: saproxylic Invertebrate assemblage: mature woodland: saproxylic 2
Invertebrate assemblage: old growth: epiphytic Invertebrate assemblage: old growth: epiphytic 1
Invertebrate assemblage: old growth: open canopy Invertebrate assemblage: old growth: open canopy 3
Invertebrate assemblage: old growth: saproxylic Invertebrate assemblage: old growth: saproxylic 4
Invertebrate assemblage: river: shingle Invertebrate assemblage: river: shingle 1
Invertebrate assemblage: scrubland: canopy Invertebrate assemblage: scrubland: canopy 1
Invertebrate assemblage: scrubland: saproxylic Invertebrate assemblage: scrubland: saproxylic 1
Invertebrate assemblage: seepage: calcareous Invertebrate assemblage: seepage: calcareous 3
Invertebrate assemblage: seepage: woodland Invertebrate assemblage: seepage: woodland 3
Invertebrate assemblage: shaded field layer: acid Invertebrate assemblage: shaded field layer: acid 1
Invertebrate assemblage: shaded field layer: dry Invertebrate assemblage: shaded field layer: dry 1
Invertebrate assemblage: stream: sandy Invertebrate assemblage: stream: sandy 2
Invertebrate assemblage: stream: silty Invertebrate assemblage: stream: silty 1
Invertebrate assemblage: temporary pond: Invertebrate assemblage: temporary pond: 1
Invertebrate assemblage: wet woodland: canopy Invertebrate assemblage: wet woodland: canopy 1
Invertebrate assemblage: wet woodland: fen carr Invertebrate assemblage: wet woodland: fen carr 2
Molluscs Molluscs 3
Moths Moths 7
Sawflies, wasps and ants Sawflies, wasps and ants 3
Spiders Spiders 3
Water fleas Water fleas 1
Woodlice Woodlice 3
 
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

This category covers all invertebrate features other than butterflies, dragonflies and damselflies.  62% of the features reported are in favourable condition.  This is just below the average for species features, but above the average for all features combined.  72% of A/SSSI and 12% of SAC features reported are favourable, with a further 12% of A/SSSI and 20% of SAC features unfavourable-recovering. 
 
Within these figures, across features on both A/SSSIs and SACs, there are some intriguing differences.  Assemblage features – when a site is notified for a combination of species – are less favourable (58%) than single species interest features (64%) - where a species is notified on a site in its own right.  Within the single species features there is considerable variation.  For example, snails (including a number of very small and rare species for which sites have been notified under the Habitats Directive) are only 29% favourable, whereas beetles (including the stag beetle Lucanus cervus, the UK's largest beetle species) are 76% favourable. 
 
A mix of adverse activities are reported; these relate to the variety of individual features within this reporting category.  Management agreements are key to achieving favourable condition.  Care is needed in interpreting these assessments, as other than for freshwater pearl mussel and white-clawed crayfish, guidance on setting conservation objectives for invertebrate features had not been fully developed at the time the assessments were made. 
 

Freshwater pearl mussel

The freshwater pearl mussel Margaritifera margaritifera has suffered considerable declines in its abundance and range in the past.  Sites have been designated for the most important remaining populations.  73% of the assessments required on SACs have been reported.  On only three rivers have freshwater pearl mussels been found to be in favourable condition (16%).  The remainder of sites are in unfavourable condition (12% unfavourable-recovering).  This probably reflects the wider conservation status of the species in the UK with most populations suffering from low abundance and/or poor reproductive success.  Pearl fishing has been an important factor in the species' decline and evidence suggests this now operates at a greatly reduced level.  Water quality and water management have been found to be particular concerns at many sites.  Agricultural activities and development pressure have also been listed as pressures on some designated sites.  Work is underway to identify appropriate management measures to improve the condition of freshwater pearl mussel sites.

White-clawed crayfish 

92% of the white-clawed crayfish Austropotamobius pallipes assessments required on SACs have been reported; 27% are favourable and 73% unfavourable.  None are unfavourable-recovering.  The principal reasons for this assessment are the continued spread of crayfish plague together with the spread of the invasive signal crayfish Pacifastacus leniusculus to previously unaffected river stretches.  Exposure of crayfish to pyrethroids from sheep dip is another significant factor contributing to the unfavourable status of the species.