Introduction to the guidance manual
9. Selection of attributes for interest features
9.1 Basic principles
Attributes are characteristics of an interest feature that describe its condition, either directly or indirectly. They can be regarded as indicators which allow judgements to be made about the condition of the interest feature. The selection of attributes in this guidance has been informed by two important principles:
  • All attributes must be measurable, so that targets can be set as part of the conservation objective for the feature.
  • Attributes should describe the condition of the feature and not the factors which influence it – in general, management activities are not suitable attributes. Thus in determining if a calcareous grassland is favourable or not, one of the attributes to be assessed may be sward height – this is what is being aimed at, not the mechanism by which it is achieved, which might be via grazing or by mowing.


9.2 Range of attributes
There are a wide range of suitable possible attributes. For example, habitat attributes may include extent, floristic composition, vegetation structure, and physical characteristics; species attributes may include population size, distribution, food availability, and habitat factors. Attributes for Earth science features may include the quality and extent of landforms/rock exposures and freedom from human induced influence in the case of active geomorphological sites.
For habitat interest features, floristic or vegetative attributes have generally been used as indicators of the condition of the habitat. However, the definitions of favourable condition for habitats are not based solely on maintaining suitable conditions for plant species. In some cases, the requirements of animal species have also been taken into account, and attributes have, where possible, been selected which convey information about the typical fauna associated with each habitat (e.g. structural features and fine-scale patterning of vegetation). (See 'Attributes for species interest features' in section 10).
9.3 Mandatory attributes
During the preparation of the guidance, care has been taken to select the minimum number of attributes which will allow reliable assessments of condition to be made. These form a core set of mandatory attributes which describe condition most economically, and are intended to be suitable for use across the UK. An assessment must be made of all of these attributes – each will contribute to the final evaluation of feature condition. The guidance adopts the term 'mandatory' to indicate these highest priority attributes.
As a general rule, attributes have been chosen which do not require expert knowledge, although staff will need training in their use. However, in some cases the use of attributes requiring additional (specialist) input is essential if a reliable and safe evaluation of feature condition is to be made (e.g. lower plants and some habitats such as cliffs and caves where specialised access skills may be needed). These situations are highlighted in the guidance.
9.4 Flexibility
However, some flexibility in the selection of attributes is acceptable (see also section 6). Some attributes may not be applicable to all examples of a particular interest feature. For example, encroachment of wetland species such as rushes is a management issue in some lowland grasslands, and in such situations the cover or frequency of wetland species is an important aspect of feature condition, and should be used as an mandatory attribute. However, in many dry grasslands use of such an attribute would be irrelevant. Another approach is illustrated by the selection of attributes for woodland habitats. Here, there are five broadly-defined categories of attribute (such as regeneration potential and tree and shrub composition) which should be incorporated within conservation objectives for all woodland features, but the selection of specific attributes within each of these categories is determined by site-specific conditions. Therefore, in some cases flexibility has been given in the guidance to choose one or more of a number of alternative attributes. It should be stressed that once chosen, it is mandatory that they are assessed.
What is key, however, is that for any particular feature on an individual site, a clear set of attributes are identified which will be used to assess the feature each time it is monitored. An audit trail of decisions which have been taken is essential to document why this set of attributes is necessary in the circumstances which apply on this site. Note that it is NOT acceptable to assess the feature using totally different sets of attributes between cycles of assessment.

9.5 Discretionary attributes
In addition, in a few cases (e.g. in the Birds guidance), "discretionary" attributes have been identified. These lower priority attributes will not contribute towards assessments of condition but may inform site management. It is up to individual agencies to determine whether or not to collect more detail than the minimum required, as this is a matter of resources. In some sets of guidance, there may be discretion to choose between alternative attributes, or where attributes may only be relevant in certain circumstances – these may also be termed discretionary, but once a decision has been made that they are to be used on a particular site, for a certain feature, they should be regarded as mandatory.