Endangered flight corridor

Of the 18 species of bats native to Britain, 13 have been identified in Southwick Country Park, in Southwick Court, and in the green fields between Trowbridge and Southwick. The thirteen includes the rare and endangered lesser horseshoe bat, a Priority Species in the UK Biodiversity Action Plan, and the internationally protected Bechstein’s bat, one of the rarest mammals in the UK.

The specialists who have identified the 13 species include the ecologists working for the developers who have submitted planning applications 20/09659/FUL for H2.5 and 20/00379/OUT for H2.6: Newland Homes and Waddeton Park Ltd. We do not believe that either of these proposed developments could possibly be executed without causing harm to the bats’ habitat and flight corridor.

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[1] Bechstein’s bat; Priority Species under the UK Post-2010 Biodiversity Framework. European Protected Species under Annex IV of the European Habitats Directive; listed as Near Threatened on the global IUCN Red List of Threatened Species.
[2] Lesser horseshoe bat: Priority Species under the UK Post-2010 Biodiversity Framework. European Protected Species under Annex IV of the European Habitats Directive.

The majority of the bats roost in Green Lane Woods and Biss Wood to the east of Trowbridge. They commute to their feeding grounds in and around SCP Nature Reserve along a green corridor of undeveloped land to the south of Trowbridge. Five of the six housing sites allocated by Wiltshire Council for development in the Trowbridge area are in this important green corridor: Elm Grove Farm (H2.1), land off the A363 at White Horse Business Park (H2.2), land south of Church Lane (H2.4), land at Upper Studley (H2.5) and Southwick Court (H2.6). The header picture at the top of this post is of a map that shows how these five sites fill the bats’ flight corridor, almost entirely, from east to west.

Our concern, as always, is for the biodiversity of our nature reserve and our focus at the moment is on the current planning application 20/00379/OUT which proposes to put 180 houses into the narrowest part of the bats’ flight corridor: the green gap between Trowbridge and North Bradley. We have tried to illustrate this with the three aerial views below.

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View 1: the bats’ flight corridor (in yellow) from the woodlands in the east to their foraging grounds in SCP and the green field between Trowbridge and Southwick;
View 2: an illustrative plan of the proposed residential development of 180 houses at H2.6.
View 3: the area of map 2 superimposed in red on the area of map 1 showing that the houses block the green gap between Trowbridge and North Bradley almost entirely.

It isn’t just the physical presence of the houses that will do the damage. Bats’ flight corridors use the dark places; residential sites come with street lights and while there are regulations to limit the level of light in public spaces, there are no regulations to limit the number or the brightness of the lights you can put up in your garden.

The applications to build on H2.4, 5 & 6 all involve the removal of trees and hedges; the plans promise to plant replacements but a replacement hedge or tree will not, for many years, support the kind of invertebrate ecosystems that feed the bats as they forage their way around the edges of the fields and along Lambrok Stream.

A meta-analysis undertaken in 2016 found that roads pose a significant threat to bats, and that casualties have included low-flying species such as the horseshoe bats. The planning applications show that the access roads to all three sites involve reducing the height of the hedges on Firs Hill to improve sightlines for traffic, but it is the tall hedges that lift the bats safely over the dangers of the road.

Our knowledge of the nature reserve’s biodiversity and ecosystems has improved over the years since these sites were first allocated for development; we have a better understanding of how our rare and endangered species interact with their wider environment. We cannot expect such drastic changes to the environment to be achieved without equally drastic effects on its wildlife.

If you are as concerned as we are by this planning application, please add your comment to the public consultation which will end on March 14th,