Dozens of butterfly species, some extremely rare, have been spotted on the fringes of a country park identified as a possible site to build flats and homes for the elderly . Green Power conducted a study on the edges of Tai Lam Country Park from April to May and identified 71 species, including two very rare ones – the yellow dart and plain hedge blue. “We are worried that the authorities will intentionally undermine or conceal the ecological value of those areas,” Matthew Sin Kar-wah, the green group’s senior environmental affairs manager, said. “Preliminary findings of our survey showed that ecology at the country park’s periphery could be more diverse than expected.” The park was one of two areas designated for possible development earlier this year. Former chief executive Leung Chun-ying’s policy address in January referred to the “relatively low ecological and public enjoyment value” of the area. With space at a premium in the city – country parks cover 41 per cent of land while residential land use accounts for 7 per cent – the Housing Society was tasked with looking at the feasibility of building on two 20-hectare sites on the edges of Tai Lam and Ma On Shan country parks. Green Power’s study of a 10km-long route from Ma On Kong to Ho Pui identified five rare butterfly species in all, including the magpie flat, and three unclassified ones. The group said the number of species recorded at the country park could be similar to other popular butterfly hot spots, such as Sham Chung and Wu Kau Tang. Thirty-four butterfly spotters have been mobilised by the group on a year-long observation in the area, which is expected to end in May or June next year. “We expect more species could be identified with more time. It is likely to reach over 100 species,” Sin said. Top butterfly hot spots are home to around 120 to 140 species. Sin said a better target for development were brownfield sites – abandoned agricultural land legally or illegally used for operations such as car parks, container storage space or recycling yards. “There are lots of brownfield sites close to Tai Lam Country Park ... why not study developing those sites first?” The Development Bureau said technical studies done by the Housing Society would provide an objective analysis on the use land at the edges of country parks and conclusions should not be made before completion of the studies. The Planning Department had also commissioned a consultant to study the condition of brownfield sites, which would facilitate the government in drafting relevant policies.