New biodiversity algorithm risks devaluing valuable wildlife habitat
A recent Guardian article has outlined the warnings from academics and conservationists that the biodiversity net gain (BNG) metric 3.0, recently published by Natural England, must be urgently improved to avoid penalising rewilding and letting valuable wildlife habitat be classed as ‘degraded’ land.
The BNG 3.0 metric outlines how new roads, houses and other building projects must be aligned to reduce damage to habitats, based on an algorithm incorporating information on habitats, such as type, size and condition. A number is then assigned to the habitat, defining how valuable it is for biodiversity, with resulting development causing no net loss of biodiversity or a 10% net gain elsewhere if nature is damaged on site.
However, common features of rewilding such as bramble, thistle and ragwort are logged into the algorithm as signs of “degradation” reducing the value and protection of such habitats. Connectivity between habitats has also not been taken into account, and therefore the vital networks for flora and fauna populations are ignored in the calculations.
A recent paper in Conservation Letters assessed a subset of house-building in England between January 2020 and February 2021 in six local authorities that had adopted the scheme. The results showed that “BNG” building developments resulted in 34% reduction in green space, with this supposedly compensated by commitments of a 20% increase in total biodiversity via expected creation of smaller, more ecologically valuable habitats, in the future. The allowance of wildlife losses today for uncertain future gains is a hazardous plan given that according to Jamie Robins, projects manager at Buglife, mitigation commitments from developers were already failing to be delivered.
Read the full responses from academics and conservationists in the Guardian article. The BNG metric is expected to be implemented in 2023, with improvements needed if we want to see the biodiversity protections promised and urgently needed.