Rare Species Inventory

The Sussex Rare Species Inventory (RSI) covers over 3,400 species. Species are selected according to strict criteria of rarity associated with their occurrence in Sussex.

The RSI does not include bat, bird or otter records

SxRSI Criteria

  • All species in the British Red Data Books including all Notable fauna and Nationally Scarce flora and British endemic taxa which have ever occurred in Sussex whether extinct or not
  • Species included in the UK Biodiversity Action Plan (BAP species)
  • Internationally rare taxa cited in the Bern Convention, IUCN Red Data lists, or EU Habitats Directive which are not covered by any of the above
  • County rarities

Although the inventory forms part of a larger database of Sussex records, no attempt has been made to include every record for every rare species. The RSI has been designed to be comprehensive for species but representative for records. This is managed in several ways:

No records of Scots Pine (Pinus sylvestris) are labelled because the species, though Nationally Scarce is of dubious provenance in Sussex.

SxRSI records are updated weekly with advice and records provided by taxonomic experts.

Confidential Records

The SxBRC holds a few records that are confidential. Confidentiality can be for a variety of reasons but usually to benefit the site or the species. Full details of these records are not disclosed but the enquirer is referred back to the Record Centre if they need further information. Please see the end of your RSI report for the number of confidential records found within your enquiry area.

A full SxRSI Species List is available on request.

Catagories of Rarity

The following is a summary of the IUCN categories of rarity. For a full listing and explanation see the IUCN Red List of Threatened Species. Also see the threat category definitions and criteria in the relevant British Red Data Books (Bratton, 1991; Shirt, 1992; Wigginton, 1999).

Extinct (EX)
A taxon is Extinct when there is no reasonable doubt that the last individual has died.
Extinct in the wild (EW)
A taxon is Extinct in the Wild when it is known only to survive in cultivation, in captivity or as a naturalized population (or populations) well outside the past range.
Critically endangered (CR)
A taxon is Critically Endangered when it is considered to be facing an extremely high risk of extinction in the wild.
Endangered (EN)
A taxon is Endangered when it is considered to be facing a very high risk of extinction in the wild.
Vulnerable (VU)
A taxon is Vulnerable when it is considered to be facing a high risk of extinction in the wild.
Near threatened (NT)
A taxon is Near Threatened when it is close to qualifying for or is likely to qualify for a threatened category in the near future.
Least concern (LC)
A taxon is Least Concern when it has been evaluated against the criteria and does not qualify for Critically Endangered, Endangered, Vulnerable or Near Threatened.
Data deficient (DD)
A taxon is Data Deficient when there is inadequate information to make a direct, or indirect, assessment of its risk of extinction based on its distribution and/or population status.
Not evaluated (NE)
A taxon is Not Evaluated when it is has not yet been evaluated against the criteria.

Regionally Scarce (Nr). occurs in 5 or fewer 10km squares in a particular region of Britain. Locally determined.

Categories of Priority Biodiversity Action Plan Species

Biodiversity UK Long List
Also known as Species of Conservation Concern. A list of 1250 species meeting one or more of four criteria (endemic, in rapid decline, internationally significant, or listed in international legislation). Those species not targeted for action (i.e. not ‘priority species’) will be subject to monitoring.
Priority Species
Those species targeted for action through species action plans or species statements and comprising the middle and short list species.
Biodiversity UK Middle List
A subset of the long list comprising approximately 400 species which are globally threatened or have declined in the UK by more than 50% in the last 25 years. The majority of these species were the subject of species action plans under development in 1997 – 1999.
Biodiversity UK Short List
A subset of the long list comprising approximately 400 species which are globally threatened or have declined in the UK by more than 50% in the last 25 years. 114 species action plans for short list species were published in the UK Steering Group Report in 1995.

Codes and Abbreviations Used in the SxRSI

West Sussex (with the Watsonian boundaries of 1852)
East Sussex (with the Watsonian boundaries of 1852)
British Butterfly Conservation Society, Sussex Branch
Sussex Atlas of Mosses, Liverworts, and Lichens (with additions & revisions to 1994)
Sussex Plant Atlas and Supplement
Sussex Botanical Recording Society

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