‘Site unitisation’ was developed as part of the conservation planning process in Wales, primarily to identify how each land parcel within the boundary of a protected area should contribute to its overall conservation value. The basic principle is that we should identify which habitat or species, if any, should be the management priority for each discrete management unit. We should also indicate a) whether any other important habitats or species are known to be present in the management unit and b) whether they are likely to be impacted positively or negatively by the proposed management. Note that the management priority in a management unit is nearly always a habitat, because even if the conservation priority in a unit is a species, our action almost always involves a habitat management response: we rarely directly manage the species.
The development phase of a site unitisation plan requires the involvement of the land owners, the land managers and ecologists who are familiar with both a) the ecological requirements of the important habitats and species and b) the local distribution of the important habitats and species on the site. As a general rule, it is better to involve as many of the important stakeholders as possible at the outset (especially those likely to be affected by the decisions), as this will reduce the likelihood of resentment and resistance as the project moves into its application phase. It is always better to be aware of any barriers to progress early in proceedings rather than after the decisions have been made.
The main purpose of the unitisation process is to form the basis for well-informed conservation management decisions. Not all site managers are comfortable with the process because it means favouring some habitats and species over others. However, this will happen anyway, just in a less considered, ad hoc process. The alternative is to divide the management funding equally which, in all probability, will mean that no habitat or species will be adequately protected into the future, though they will all be discriminated against equally. A case study illustrating the site unitisation process can be found here.