Ecological Mitigation, Compensation and Enhancement

Planning authorities have a legal responsibility to conserve and enhance biodiversity under what is known as the Biodiversity Duty. One tool that informs decisions by developers, ecologists and planning authorities is the Mitigation Hierarchy.  This essentially means that biodiversity impacts from a proposed development should be preferentially be avoided, then mitigated, and as a last resort, compensated for. Planning policies make reference to this concept – the National Planning Policy Framework states that planning permission should be refused if significant impacts on biodiversity have not been avoided, mitigated or compensated for.

Examples of avoidance might be to relocate a proposed development entirely, move elements of a development (e.g. re-siting the base of an electricity pylon away from deep peat blanket bog) or changing the timing of works (e.g. avoid vehicle movements through a site in the early morning in the black grouse lekking season). Avoidance is frequently the most effective and cheapest option, but it requires biodiversity to be considered early in the planning process.

Ecological mitigation can be temporary during the construction phase of a development, or permanent for the lifespan of the development. Examples include the installation of fencing to either exclude protected species from a construction area (e.g. newt fencing) or allow the capture and translocation of protected species such as great crested newts or water voles. Another example of mitigation is the installation of underpasses in a road, to enable species to safely cross and to reduce the fragmentation of habitat. Some mitigation requires licensing from the Statutory Nature Conservation Agency, e.g. Natural England. Bat mitigation can range from the provision of suitable bat boxes in the grounds of a building, or ‘bat tubes’ built into a building, to more complex structures such as a ‘bat loft’ if a proposal would require the loss of a maternity roost of species such as brown long-eared bat.

Compensation refers to where biodiversity impacts cannot be avoided on a development site, so measures are taken beyond a site boundary, such as the creation of new habitat for a protected species. Compensation is a last resort and should not be considered before avoidance and mitigation. When a development affects a Special Protection Area (SPA) or Special Area of Conservation (SAC) (often referred to as Natura sites), there are strict definitions of ‘mitigation’ and ‘compensation’ within European Directives which need to be followed.

Ecological enhancement refers to a site being in better ecological ‘condition’ in the presence of a development than previously. For example, a development on a site of low ecological value can incorporate bird and bat boxes, areas of native wildflowers, and/or ponds, leading to a higher biodiversity value than prior to the development.

At Ellendale Environmental we have experience of designing and implementing mitigation protocols, including applying for any necessary licences, to support your development proposal while avoiding unnecessary impacts on biodiversity.

John McTague