ENVIRONMENT: THOMSON ECOLOGY
be demonstrated that the works will not have an adverse affect on the integrity of the designated site before the works can be carried out.
More often, maintenance and enhancements of the existing rail network could have an impact on protected species. Sometimes this can be dealt with simply by scheduling the works at an appropriate time of year, for example, planning to undertake any necessary vegetation removal outside of the breeding bird season. Sometimes, though, it may be necessary to obtain licences from the appropriate authority to trap and remove protected species in advance of the works. The licensing process can take around two months and there will be restricted times of the year when the actions set out in the licence can be undertaken. For example, it is only possible to trap and remove great crested newts when they are active, typically between March and October. Of course, knowing what protected species are present and whether there is a need for a licence requires a good baseline survey sometime in advance of the works taking place.
There are also legal controls preventing the spread of Japanese knotweed and certain other non-native plant species. If these are present at the work site, it may be necessary to eradicate the plant in advance of any works, or at least develop a strategy which prevents the further spread of the plant.
New railway developments
Despite the potential benefits of creating new rail side habitats, the development of new railways poses the same challenges in respect of biodiversity as any other development, as well as some which are specific to railways. A major challenge may be the potential impacts on designated nature conservation sites, such as those protected under the Habitats Directive or domestic legislation. A further challenge is likely to be the presence of protected species and their habitats and finally, there are other habitats and species which may not be strictly protected but are
still important components of the existing ecological network. Biodiversity is best considered at all stages of the project, from route selection to post-construction monitoring.
Generally, early consideration of biodiversity issues means better outcomes for both the project and biodiversity. This is for two main reasons. Firstly, working with wildlife is a highly seasonal activity. There are critical time periods for carrying out surveys and undertaking any required mitigation. Therefore, any such works need to be carefully planned to avoid holding the whole project up while waiting for the appropriate season. Secondly, the easiest way of managing the negative effects of development on biodiversity is usually to avoid them altogether. This can only be done if biodiversity is a key consideration at the early design stages. As well as being good practice, this approach should also help the project through the consenting process and mean that the project will be less costly to implement.
Due to the engineering constraints associated with new railways, avoiding all impacts on biodiversity is unlikely to be achievable. New habitats may therefore need to be provided in compensation for any which are lost. Nowadays, there are established techniques to compensate for many negative effects. These techniques can work provided that the extent of the compensation is sufficient and there is adequate commitment to the management and maintenance of new habitats in the long term. However, some habitats take hundreds of years to establish and are effectively irreplaceable. Impacts on these habitats may prove impossible to fully compensate on the scale of a human lifespan.
Any new rail development also brings with it opportunities to provide features that are beneficial for biodiversity. The overall aim should be to achieve an all round positive outcome, rather than simply implement the minimum measures required by law. As described above, a new railway will inadvertently create new habitats for wildlife
What cannot be seen so easily from the window of the train is the impressive diversity of plant and animal species; around 2,000 species of plant, nearly 50% of the total number in the UK, have been found growing alongside our railways.
WWW.THECONNECTSERIES.CO.UK
Despite the potential benefi ts of creating new rail side habitats, the development of new railways poses the same challenges in respect of biodiversity as any other development, as well as some which are specifi c to railways.
which will eventually contribute to biodiversity conservation. Including additional features to benefit biodiversity, it may bring about the creation of more valuable habitats more quickly. It can also pay to think about the habitats created, for whatever reason, as part of a contribution to a wider, functioning ecological network. Taking the strategic view should yield greater benefits for biodiversity and ensure better value for money.
An idea gaining momentum in the UK is biodiversity offsetting. This is where the developer meets the requirements for providing compensatory habitats through making a financial contribution to a third party. The third party is then responsible for the compensation requirements of one or more developments. The land used for providing compensatory habitats would normally be located within a strategic framework established by the local planning authority. At the moment, the government is trialling biodiversity offsetting in six pilot areas of the UK using a system developed by Defra to calculate how much habitat should replace that lost to development. Biodiversity offsetting using the Defra system is however already being used more widely and could well be applied to new rail projects in the near future.
No matter how the biodiversity elements of a railway project are delivered, it is critical to have a competent ecologist as part of the senior level project management team to advise and guide the project team through the complexities of wildlife legislation and policy, to rigorously assess the impacts of the development and to advise on any mitigation and compensatory measures.
RailCONNECT 37
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