Green Power announced the latest results of the Butterfly Survey. The survey currently covers 11 butterfly hotspots, and was carried out from June to October this year. A total of 172 species were recorded, accounting for around 65% of the total number of butterfly species in Hong Kong. Among all butterfly hotspots, Tai Lam Country Park ranked top for total species and numbers of rare species, indicating the site is very rich in butterflies. Mr. Matthew Sin, Senior Environmental Affairs Manager of Green Power, urged the government to withdraw the plan for developing the periphery of Tai Lam Country Park.
A total of 127 butterfly species were recorded at Tai Lam Country Park, accounting for nearly half of the total in Hong Kong. This included 9 very rare species, 14 rare species and 4 unclassified species. Matthew remarked that the butterfly ecology at the site is surprisingly rich. "Since 2008 when we started our butterfly surveys, we have only recorded over 120 species at 4 hotspots for one or two years. Tai Lam Country Park is a new site for our monitoring this year. In about seven months, taking into account the preliminary survey in April and May, we have already recorded such a high number of species. This is amazing!"
Matthew pointed out that the result also reflected the rich diversity of vegetation at the periphery of Tai Lam Country Park. For example, some butterflies recorded at Tai Lam Country Park – Peacock Royal (Tajuria cippus) and Gaudy Baron (Euthalia lubentina) – both have larvae that feed on the plant species Witches' Broom (Scurrula parasitica); and the caterpillars of Falcate Oak Blue (Mahathala ameria) feed on Creepy Mallotus (Mallotus repandus). Both Witches' Broom and Creepy Mallotus are uncommon plants in Hong Kong. The records of these butterflies indicate that these plants are also present at the site.
While Tai Lam Country Park vegetation is mainly plantation, this is proof that vegetation at the periphery is gradually reviving and gaining ecological value. "The government has indicated the wish to seek marginal country park land of low ecological value for building houses. Our survey results showed that the Tai Lam Country Park periphery is not suitable for such development," Matthew remarked. He reiterated the opposition to developing any country park land.
Matthew noted that the newly released Policy Address still mentioned development of country park peripheries, and the Hong Kong Housing Authority is already seeking a consultant to carry out the related feasibility study. The country park development plan has stirred up a lot of controversy among the public and should be halted immediately. And while the government is planning to develop the Kam Tin area of Tai Lam Country Park, there is other land available for use.
According to an analysis by Green Power, there is a 20-hectare brownfield site within the hundred hectare area (about 1 km2) around Tai Lam Tunnel Toll Plaza. This is about the area of the Tai Lam Country Park periphery the government is considering developing. Matthew proposed that the government prioritise the brownfield development and hoped that in the upcoming discussion of the Task Force on Land Supply, the brownfield site would be included. He will later submit the butterfly survey results and suggestions to relevant departments.
Apart from Tai Lam Country Park, the butterfly hotspots with highest numbers of butterflies in 2017 were Sha Tau Kok and San Tau. Totals of 112 and 99 butterflies were recorded at the two sites, respectively; including 16 and 12 rare species. Matthew pointed out that a decrease was observed in several butterfly hotspots, particularly at Luk Keng, Pak Sha O/Lai Chi Chong, and Lok Ma Chau/Long Valley/Ho Sheung Heung.
The decade of survey work has witnessed great environmental changes, for example, at Pak Sha O and Ho Sheung Heung. Village houses and car parks have boomed over the years, in areas that were previously habitats for butterflies. Butterfly diversity is certainly threatened.
Matthew hoped the upcoming discussion on land supply can lead to better planning of rural landuse. He also remarked that this year's survey was only carried out for 5 months, and would continue to the second season of next year. Hence, the numbers of species recorded may rise.
Note 1: The total number of butterfly species in Hong Kong is about 265.
The Butterfly Survey Scheme was launched in 2008, and was the first of its kind in training members of the public to become qualified Butterfly Surveyors. The team invests substantial efforts to collect data on butterfly ecology in long term. Currently there are 286 qualified surveyors, monitoring 11 butterfly hotspots. The number of butterfly hotspots covered has increased from three in the first year with new one added each year. The sites currently being monitored are: San Tau (Lantau Island), Luk Keng (Fanling), Wu Kau Tang (Tai Po), Lam Tsuen (She Shan and Ng Tung Chai, Tai Po), Yuen Tun Ha (Tai Po), Shum Chung and Yung Shue O (Sai Kung), Sha Tau Kok, Pak Sha O and Lai Chi Chong (Sai Kung), Mui Wo (Lantau) and Lok Ma Chau-Long Valley-Ho Sheung Heung and the site added this year - Tai Lam Country Park (Kam Tin). Regular surveys are carried out from June to May of the following year. The figures for 2017 were collected from June till 8 October. The figures for Tai Lam Country Park (Kam Tin) also included those from preliminary surveys in April and May, 2017.
For the newly added site of Tai Lam Country Park, in view of government’s invitation in May to the Hong Kong Housing Authority to study the development potential of two areas of country park periphery lands which included Tai Lam Country Park, our monitoring route also focuses on the peripheries, starting at Ma On Kong Warden Post, passing Tsing Tam Reservoir and ending at Ho Pui: a total length of 10km.