Since the Frontier Closed Area at Sha Tau Kok being opened up during 2012, Green Power has been conducting butterfly surveys in the area. So far, 97 species have been recorded, representing 35% of the total number of species in Hong Kong. Among these, 9 are rare species and 4 are very rare. Sha Tau Kok has been a closed area for nearly 60 years. There was no study of the local butterfly ecology until February 2012, when the area was opened. The site is now recognized as an important butterfly hotspot of Hong Kong, with rich diversity.
Rare species recorded
Apart from the high diversity of butterflies at Sha Tau Kok, there are many notable species. For example, our Butterfly Surveyors recently recorded Euthalia niepelti, which had not been sighted after being first recorded in Fung Yuen, Tai Po, in July 2011. Sha Tau Kok is the second site where the species has been found.
In addition, the very rare Large Banded Swift (Pelopidas subochraceus) and Forget-me-not (Catochrysops strabo) were also found. The former has a narrow distribution in Hong Kong – in Ngau Tam Mei and Nga Kai Shan, Yuen Long; and Fung Yuen, Tai Po. The Sha Tau Kok discovery is a new addition to the database. Forget-me-not was once a common species in Hong Kong but became very rare in the past decade for unknown reason. Besides Sha Tau Kok, it is also found at other survey sites including San Tau, Tung Chung; Wu Kau Tang, Tai Po; and Sham Chung and Yung Shue O, Sai Kung. Very Rare Species refers to those with very narrow distributions. The situation in which a very rare species is reported from several sites is unusual. The sudden increase in numbers may be due to a comeback of the species, or improvements in the natural environments. But it is still too early to draw conclusions.
In fact, before the formal survey at Sha Tau Kok, our Butterfly Surveyors had spotted Angled Red Forester (Lethe chandica) whilst being trained. The species was first recorded in Hong Kong in 2011, with several reports from Tai Po Kau and Wu Kau Tang. The new record at Sha Tau Kok helps to determine its distribution in Hong Kong. All these records indicate that Sha Tau Kok is an important butterfly hotspot, and it is time to take proper action to protect the local butterfly ecology.
List Robin's Nest woodland as Conservation Area
Sha Tau Kok is next to Robin's Nest, which is connected to Pat Sin Leng of Tai Po as well as Ng Tung Shan of mainland China. The 5,600-hectare ecological corridor is equivalent to 300 times the area of Victoria Park. Sha Tau Kok also has numerous habitats such as fung shui woods, rivers, wetlands, forests and farmlands. According to the present Outline Zoning Plan, there are only 3 hectares of Conservation Area in Sha Tau Kok. By contrast, Village Type Development and Recreation Uses that could be turned into small houses and golf courses occupy 39 hectares and 7 hectares, respectively. It is obvious that the present planning of Sha Tau Kok fails to safeguard most ecologically valuable places, particularly in terms of butterfly ecology.
Since the opening up of Sha Tau Kok, visitors and all kinds of development such as leisure farms, war game sites and car parks have arrived. The number of small houses in the area is also on the rise. Now, there is even a large-scale village housing estate under construction. Just a few hundred metres from where Large Banded Swift and Forget-me-not were found, construction work is being carried out. There is indeed cause for concern regarding local butterfly ecology.
The government should develop Sha Tau Kok into a green corridor and list the woodland connecting Sha Tau Kok and Robin's Nest as a Conservation Area or Site of Special Scientific Interest. Besides conservation of butterflies, it can function as a buffer region between Sha Tau Kok village and the proposed Robin's Nest Country Park that is currently being studied.