Research conducted by the Royal Town Planning Institute (RTPI) has found that almost half of the ecological features outlined in planning proposals were missing from the participating housing developments.

Between June and August 2024, a research team based in the University of Sheffield’s planning school examined 42 developments across five local planning authorities in England.

The team found that only 53% of the ecological enhancements outlined in the planning proposals were present; 19% of which was made up of newly planted trees.

Other missing commitments include 48% of native hedges, 75% of both bird and bat boxes, 100% of invertebrate boxes, 83% of hedgehog highways, and 39% of the trees were either missing or dead.

Additionally 60% of the areas wetland grassland, and 59% of wildflower grasslands had either been sown incorrectly, or mowed incorrectly, resulting in its richness being considerably reduced.

The data report accredits these findings to a range of factors, including unclear expectations, weak local policy guidance on biodiversity, and poor-quality landscape and ecology management plans.

Research was conducted across 291 hectares, amounting to almost 6000 houses, which equates to 4,658 promised trees and 868 bird and bat boxes.

Each of the developments, comprising more than 10 houses, were granted planning permission after 2012, when the National Planning Policy Framework first required developments to demonstrate a net gain for biodiversity, but prior to the introduction of the biodiversity net gain legislation.

The full report can be found here.