Poor connections between forest areas, unsuitable surrounding habitats, an inadequate size of forest and omission of some forest types, all affect the ability of a protected network to conserve biodiversity and ensure the long-term survival of species found in such habitats.
There are three guiding principles that should be used in the design of PFAs, as cited by the researchers:
- Representativeness - all forest types, threatened habitats and endangered species should be included
- Spatial design - size, connections with other forest areas and habitat diversity all play an important role
- Site quality - suitable habitats and condition of the site, including structure of the vegetation and presence of old growth elements are also important
The study assessed how forest planners from 21 European countries participating in the COST E271 initiative selected PFAs. They found that the planners did not tend to follow the recommended scientific guidelines. Only 26 per cent of the 101 forest types assessed were selected using all three recommended criteria. For the remainder, only limited use had been made of guidelines to identify the conditions that contributed most to the preservation of biodiversity. Forest planners gave three main reasons for not using the suggested guidelines:
- There is a lack of supporting ecological data and practical information for choosing sites. Where this is the case, the researchers recommend using vegetation types as indicators for biodiversity and species distribution, complemented by modelling techniques to help select sites.
- Planners prefer to seek advice from individual experts over standardised guidelines. The researchers suggest it is essential for forest managers and scientists to form partnerships during the entire planning process, but they should use a systematic approach as a guide.
- Systematic conservation planning is time-consuming, expensive and competes with other uses for the land. For example, it can involve setting aside areas of forest of high commercial value. Justification for the inclusion of forest areas containing biodiversity hotspots, not currently included in the PFA network, is therefore important to optimise PFA efficiency and protect a wealth of species under threat from commercial interests, in accordance with MCPFE2 decisions.
Recent work has shown that a network of reserves can provide protection to species whose range is shifting under the impact of climate change. The researchers argue that additional PFAs, chosen using the three guiding principles, should be added to the existing network to ensure that there is an adequate range of habitats capable of protecting threatened species in the future.