English Heritage Stonehenge Environmental Improvements Project ...

Table 1 Criteria used in evaluating the relative botanical importance of habitats
Value
Examples of Evaluation Criteria
International Importance • High importance and rarity, international scale and limited potential for
substitution;
• A internationally designated site (Special Area of Conservation SAC, Special
Protection Areas SPA);
• Presence of Internationally rare species;
• Woodland: Semi-Natural Ancient Woodland greater than 20ha including a
combination of type stands;
• Grassland: Unimproved and species-rich grassland greater than 0.5 ha including
internationally rare habitats;
• Arable sites with threshold scores of more than 90 points 11 .
National Importance • High importance and rarity, national scale, or regional scale with limited
potential for substitution;
• A nationally designated site (Sites of Special Scientific Interest (SSSIs), National
Nature Reserves (NNRs) etc.;
• A viable area of a priority habitat identified in the UK BAP, or of smaller areas of
such habitat which are essential to maintain the viability of a larger whole;
• Woodland: Semi-Natural Ancient Woodland greater than 5ha;
• Grassland: Unimproved grassland greater than 10 hectares; over 10 positive or
unimproved grassland indicators;
• Arable sites with threshold scores of 45-89 points.
Regional Importance • High or medium importance and rarity, local or regional scale, and limited
potential for substitution.
• Any regularly occurring, locally significant population of a Nationally Scarce
species (occurs in between 16 to 100 10km squares of the national grid) or in a
Regional BAP or relevant Natural Area on account of its regional rarity or
localisation; or
• Woodland: Semi-Natural Ancient Woodland between 2 and 5ha;
• Grassland: Unimproved grassland greater than 0.5 hectares, over 10 positive or
unimproved grassland indicators.
County Importance • High or medium importance and rarity, local or regional scale, and limited
potential for substitution. A site designated as being of County Importance i.e.
County Wildlife Site (CWS);
• A viable area of Key Habitat identified in the County BAP;
• Any regularly occurring locally significant population of a species which is listed
in a County Red Data Book, BAP or County Rare Plant Register on account of its
regional rarity or localisation;
• A regularly occurring locally significant number of a County important species;
• Woodland: Semi-Natural Ancient Woodland greater than 0.25 ha with 10 or
more AWIS;
• Grassland: Unimproved grassland greater than 0.5 hectare with 6 positive or
unimproved grassland indicators;
• Arable sites with threshold scores of 30-44 points. Vascular ;
• Plants: According to KWT 2005 12 , >150 points (locally scarce or rare in County
= 25 points).
11
Byfield, A. and Wilson, P. (2005). Important Arable Plant Areas: Identifying priority sites for arable plant conservation in the
United Kingdom. Plantlife International, Salisbury, UK.
12
Kent Wildlife Trust, 2005 Local Wildlife Sites in Kent Criteria for Selection and Delineation. Kent Wildlife Trust.
September 2008 3 Phase II Botanical Surveys
11108605R_Botanical_DW_09-08
Chris Blandford Associates