Guidelines for selection of biological SSSIs
Rationale, Operational approach and criteria, Detail guidelines for habitats and species groups
Please note: These guidelines are under revision
The Joint Nature Conservation Committee is the forum through which the three country nature conservation agencies, Natural Resources Wales (NRW),Natural England and Scottish Natural Heritage (SNH), deliver their statutory responsibilities for Great Britain as a whole and internationally.


The Joint Nature Conservation Committee (JNCC) is the statutory adviser to Government on UK and international nature conservation. Its work contributes to maintaining and enriching biological diversity, conserving geological features and sustaining natural systems. JNCC delivers the UK and international responsibilities of the four country nature conservation agencies - Council for Nature Conservation and the Countryside, Natural Resources Wales, Natural England and Scottish Natural Heritage. JNCC, originally established under the Environmental Protection Act 1990, was reconstituted by the Natural Environment and Rural Communities Act 2006. JNCC, working with the nature conservation agencies, is the focus for the guidelines for the selection of biological Sites of Special Scientific Interest (SSSIs).
The nature conservation agencies have a duty under the Wildlife and Countryside Act 1981, as amended, to notify any area of land which in their opinion is 'of special interest by reason of any of its flora, fauna, or geological or physiographical features'. Such areas are known as Sites of Special Scientific Interest (SSSIs). The notification is made to owners and occupiers, local planning authority and the Secretary of State, who may make representations or objections to the nature conservation agencies regarding the notification. Any representation or objection made must be considered by the nature conservation agencies before a decision is made by them to confirm the notification.
In 1989 the then Nature Conservancy Council published guidelines for the selection of biological SSSIs. Since 1991 JNCC has been the focus for the production and revision of the guidelines.
Since 1989, a series of revisions have been made in the form of additional or revised chapters. However, the underlying rationale and operational approach have remained intact and broadly fit for purpose. Nonetheless, an inter-agency review has been completed, taking into account changes in governance, legislation and wider approaches to nature conservation being developed within the UK Biodiversity and country biodiversity strategies. Former Parts A and B have been merged into a single  Guidelines for the Selection of Biological SSSIs Part 1: Rationale, Operational Approach and Criteria for Site Selection. The biological guidelines set out general principles upon which the nature conservation agencies reach judgements regarding special scientific interest. These principles are supplemented by details of wildlife habitat types and species groups.
The guidelines for the selection of geological and physiographical SSSIs are published separately by JNCC in volume 1 of the Geological Conservation Review.
In Northern Ireland the designation Areas of Special Scientific Interest (ASSIs) is the equivalent of the SSSIs. The responsibility for the identification and designation of these sites rest with the Environment and Heritage Service, Northern Ireland. View the Guidelines for the selection of biological ASSIs.
Individual habitat and species chapters together comprise Part 2. These have each been updated to reflect organisational changes, and minor technical revisions have been made.  The need for more comprehensive revision is currently under assessment, and a rolling programme of updating individual chapters is underway.
Chapters available for download are the current, most up-to-date versions.  These will be replaced as newer versions become available.


Current                                                        Proposed revisions           Status of revised chapters                            

Part 1:

Completed Completed

Rationale, Operational Approach and

Criteria for Site Selection

Current Proposed revisions Status of revised chapters

Part 2:

Detailed Guidelines for Habitats and Species


Introduction  (PDF, 2mb)   subject to revision




Chapter 1 Coastal and Marine habitats  (PDF, 213 kb)       

1a  Coastlands   

Table 1 Habitat selection units for coastlands     

Table 2 Coastal habitat selection units and their NVC equivalents    

1b Intertidal habitats    

1c saline lagoons:  

Chapter 1

Coastal and Marine



1a  Coastlands   - subject to revision


1b Intertidal habitats   - subject to revision


1c saline lagoons  - subject to revision

Chapter 2 Woodlands   (PDF, 213 kb) 

2a Woodlands - general

Table 3  NVC - woodland and scrub communities          

Table 4   Extent and localisation of British woodland Stand Types       

Table 5    Main semi-natural structural types of tree layer in British woods      

Table 6    An approach to integrating differing woodland classification
schemes for SSSI selection         

Table 7    A preliminary attempt to indicate the general relationship between
 the Stand Type classification and for woodland          

Table 8    Field measures of the NCR criteria for British woods  

2b Veteran trees


Chapter 2



2a Woodlands (general)   - subject to revision


2b Veteran trees  - subject to revision

Chapter 3 Lowland grasslands  (PDF, 79 kb)         

Table 9  NVC - lowland grassland communities 


Chapter 3

Lowland grassland

subject to revision

Chapter 4 Lowland heathland (PDF, 102 kb)

Table 10  Heathland classification, distribution and selection requirements   


Chapter 4

Lowland heathland

subject to revision

Chapter 5 Non-montane rock habitats (PDF, 101 kb)         

Table 11 Geographical variation in the main floristic features of limestone


Chapter 5

Non-montaine rock habitats

subject to revision
Chapter 6 Freshwater habitats  (PDF, 205 kb)   

Table 12  TWINSPAN classification of standing water sites – submerged       
and floating vegetation      

Table 13  Key to standing water types (submerged and floating species)         

Table 14  Physical characteristics of standing water site types   

Table 15  NVC communities most common in emergent fringes of standing  
water site types        

Table 16  Classification of ditch vegetation types  

Table 17  Key to river types  


Chapter 6

Freshwater habitats

subject to revision
Chapter 7 Fens  (PDF, 220 kb)

Table 18  NVC - communities of minerotrophic mires      

Table 19  Description, habitat conditions and range of fen communities 


Chapter 7


subject to revision
Chapter 8 Bogs  (PDF, 265 kb)

Table 20  Mire microforms      

Table 21 NVC - bog communities and subdivisions (Rodwell)  
and bog microtopes and communities (Lindsay et al.)


Chapter 8 


subject to revision
Chapter 9 Upland habitats  (PDF, 570 kb)   

Table 22 Synonymy of Birks & Ratcliffe and NVC upland vegetation types 


Chapter 9

Upland habitats

subject to revision
Chapter 10 Artificial habitats (PDF, 61 kb)    

Table 23 Types of artificial habitat 




Chapter 10

Artificial habitats

subject to revision



Chapter 11 Vascular plants (flowering plants, ferns and their allies) (PDF, 175 kb)       

Table 24 Red Data Book species of vascular plants        

Table 25 Nationally scarce species of vascular plants


Chapter 11

Vascular Plants (Flowering plants, ferns and allies)

subject to revision
Chapter 12 Non-vascular plants (PDF, 97 kb)          

               Table - Nationally rare species & Table Nationally scarce species


Chapter 12



12a Bryophytes (general) -

subject to revision


12b Rivarine hygrophilous bryophytes - to be drafted


Chapter 13 Mammals   (PDF,  129 kb)  

13a Mammals - general

Table 26 Status and distribution of British mammals       

13b  Water vole  


Chapter 13

Lichens and lichenicolous fungi

13a Lichens (general)  - to be drafted


13b Snowbed lichens  - to be drafted

Chapter 14 Birds (corrected) (PDF, 301 kb)

Appendix A Criteria for Ramsar Sites and Special Protection Areas          

Appendix B An estimate of numbers of birds breeding and wintering in Britain  

Table 27 Abundance estimates of British breeding and wintering birds          

Appendix C Breeding bird assemblages of different habitats          

Table 28 Breeding bird assemblages of different habitats          

Appendix D   Regional population densities in the uplands  

References   (Chapter 14) 


Chapter 14


14a Fungi (general)  - to be drafted


14b Grassland fungi - subject to revision

Chapter 15 Reptiles and amphibians  (PDF, 60 kb)

Table 29 A scoring system for the selection of sites with assemblages           
of amphibians         


Chapter 15


15a Algae (general)  - to be drafted


15b Stoneworts  - to be drafted



Chapter 16 Freshwater and estuarine fish (PDF, 75 kb)


Table 30 British freshwater, anadromous and estuarine fish and their distribution   


Chapter 16



16a Mammals (general) - subject to revision     


16b  Water vole - subject to revision

Chapter 17 Invertebrates (PDF, 139 kb)

17a     Invertebrates- general    

17b     Butterflies     

17c      Dragonflies 


Chapter 17


subject to revision
Chapter 18 Fungi (PDF, 73 kb)

Chapter 18a  Grassland fungi 


Chapter 18

Reptiles and amphibians

subject to revision

Chapter 19 Freshwater and estuarine fish


subject to revision


Chapter 20 Invertebrates


20a     Invertebrates (general) - subject to revision    

20b     Butterflies - subject to revision   

20c      Dragonflies - subject to revision


 Acknowledgements    (PDF, 6 kb)   Acknowledgement subject to revision
Please cite as: JNCC, Guidelines for selection of biological SSSIs, Please note: These guidelines are under revision