Planning guidance for hedgehogs

Photo by Tom Marshall

The West-European hedgehog is an iconic British species, but they are undergoing a worrying decline. In urban areas, up to a third of populations have been lost between 2000 and 2014 and over half of rural populations have been lost in the same time (PTES & BPHS 2015).

Hedgehogs face threats in both urban and rural areas with habitat loss, fragmentation and the reduction in habitat quality being major issues. Agricultural intensification and urbanisation are contributors to these, with reduced habitat features, fewer invertebrates, increased hard surfacing and impermeable boundaries resulting in fewer nesting and feeding areas, less connected habitat patches, greater risks of predation and more isolated populations. See the Conservation Strategy for the West-European hedgehog document, here, for more information.

Hedgehogs are listed as a UK ‘Priority Species’ under S41 of the NERC Act (2006). They also have limited protection under Schedule 6 of the Wildlife and Countryside Act (1981) as amended, which means they may not be caught or trapped without a licence. No legislation currently addresses the causes of decline in hedgehog populations.

Hedgehog habitat requirements

There are three main hedgehog habitat requirements to consider in a planning context:
1) High quality feeding habitat - moist grassland, rotting wood and wildflowers to encourage invertebrates.
2) A range of nesting opportunities – medium sized fallen leaves from deciduous trees such as oak and beech, as well as supporting structures for winter and breeding nesting eg. log piles or bramble patches. Tussocky grassland and shrubbery in gardens is required for day nesting during the active season.
3) The importance of well-connected habitat - hedgehogs roam on average ~2km a night and an urban population is thought to need at least ~1km2 of well-connected habitat to remain viable.

 

Predicting likely presence of hedgehogs on a site

• Recent records obtained from county records centre or NBN Atlas
• Presence of suitable habitat

If hedgehogs have been recorded locally and suitable habitat is present, it is likely that due to the wide-ranging behaviour of hedgehogs, the habitat will be used in some form. The significance of the habitat will depend on how it is being used; for foraging, summer nesting, hibernation, or both. A 200m length of bramble can support upwards of 10 hibernating hedgehogs, and this habitat could be the most significant hibernating resource in the locality. Its removal could therefore have a high impact on the local hedgehog population. Similarly, the removal of an important moist grassland feeding area could impact on populations within 75 hectares of the site (Cresswell et al. 2012). Other than looking for field signs, the standardized way of detecting hedgehogs is through the use of footprint tunnels, more information can be found here.

Mitigating the impacts of development

Three main impacts of development to consider:

1) Injury or death of hedgehogs during construction
2) Habitat change and reduced connectivity
3) Poor green space management post-development

Avoiding injury or death of hedgehogs during construction

The impact of construction can be minimised by considering the timing and method of clearance. Whilst there is no good time of year for habitat clearance due to hedgehogs’ use of nests all year round, an autumn clearance will avoid the bulk of the breeding season, will be before hibernation and will also avoid the nesting bird season. A high cut, low cut method of removal will also allow a check for nests in between cuts. If a hedgehog is injured during habitat clearance or construction, please phone British Hedgehog Preservation Society for advice and the location of your nearest rescue centre.

Photo by Ali North

An example of a hedgehog breeding nest. All nests are well hidden and tend to be difficult to see.

Mitigating the impact of habitat change and reduced connectivity

Broad scale connectivity

Large scale developments will offer the best opportunity for influencing broad scale connectivity, but all developments should be well designed with wildlife in mind. Regardless, connectivity of green spaces across a development is very important, as well as the retention of existing habitat features. The creation of habitat features such as those mentioned above can support high densities of hedgehog. Incorporating existing natural features and linking these with green infrastructure like footpaths, cycleways and newly created habitat is a great way of ensuring effective connectivity at the earliest stage. This approach has been taken by a pioneering eco-friendly development in Cambourne, Cambridgeshire.

Major roads increase habitat fragmentation for hedgehogs, especially if walls are constructed in between carriageways. Road mitigation such as overbridges, underpasses and culverts are likely beneficial, as long as they are not permanently water logged or water filled. 

Fine scale connectivity

At a finer scale, boundaries should be permeable to hedgehogs, with the use of 13x13cm ground level access holes. These holes will also be critical for other species negatively impacted by habitat fragmentation, such as the common toad Bufo bufo. Each fenced or walled garden should be connected to every other neighbouring piece of land with a hedgehog hole. Specific hedgehog holes can be built into gravel boards, and gates can have a gap height of 13cm to ensure permeability. This is a cheap and very effective way of improving urban connectivity for ground inhabiting species. The use of Hedgehog Street Hedgehog Highway plaques to mark the purpose of the holes also provide a PR opportunity to promote wildlife friendly building. We have a limited number of Hedgehog Highway plaques available to purchase for Ipswich developments, please get in touch for more information.


Hedgehog friendly concrete gravel board by Goddard Fencing (Photo by Ann Havard)

A collaborative effort is needed to improve garden connectivity on a large scale

To improve the situation for hedgehogs we really need to work together. Where do you fit in? Can you help?


• We need awareness amongst existing gardens owners to be increased (through the national project Hedgehog Street, BHPS, RSPB and Wildlife Trust projects such as our own)
• We need ecological consultants and planning officers to push for hedgehog mitigation
• We need hedgehog friendly fencing and walls to be standard in all new builds and we need fencing options to be easily available and promoted by contractors, architects, and landscapers.