Halnaker Hill farm in West Sussex recorded an “amazing” abundance of 5,290 butterflies two years after 133 hectares of former wheatfields were converted into a commercial nature restoration project. The site was reseeded with a specialist wildflower mix after a final 2024 harvest, and managers planted seven kilometres of hedgerows, created seven hectares of new woodland, dug three ponds, seeded 54 hectares of herbal leys, and used controlled mob-grazing on existing chalk grassland. Independent ecologist Neil Hulme surveyed the site and counted 85 rare small blue butterflies, seven dingy skippers not previously recorded on the fields, 547 small heath butterflies, scores of common blues and green hairstreaks, and eight sulphur pearl moths. Halnaker Hill Natural Capital funds the work by selling biodiversity net gain credits that developers buy to meet legal BNG obligations; the project is delivering more than 850 BNG units. Nick Heasman, head of natural capital for the South Downs, said the survey proves how quickly nature can rebound when given space and care, and Hulme noted that for chalk soils the main practical steps are scraping nutrient-rich topsoil and sowing specialist chalk grassland mixes. The site forms part of the South Downs authority’s ReNature programme, which is transforming more than 7,700 hectares across the region.
