Yuen Tun Ha, in Tai Po District, was added to the Butterfly Surveyors' survey locations in 2010. 65 species of butterfly species were initially recorded, including 3 very rare and 7 rare species. One of the most exceptional species recorded is the rare Spotted Royal (Tajuria maculate). Its distribution is very limited in Hong Kong, and this is the first time it has been recorded at Yuen Tun Ha.
In July 2010, Green Power received reports of many withered plants found along the main footpath at Yuen Tun Ha. Investigations revealed traces of herbicides on plants, as well as charred vegetation where an area of a field had been burnt. It appears the damage to vegetation was caused by human activities. Half of the affected route, 500 metres in length, was within the survey route of Butterfly Surveyors. Later, we found that some of the trees had been purposely snapped or "girdled". Those trees will then lose their ability to transport water and nutrients, leading to slow death.
Since many of the damaged plants are caterpillar food plants and adults' nectar plants for many butterflies, this damage will severely affect the butterfly ecology. If the condition persists, some of the rare butterfly species may disappear. We have sent a letter of complaint to different departments of the Government regarding the damage, and requested follow-up actions. As the area involves a water catchment area, we have visited the area together with staff from the Water Supply Department. Staff from the Lands Department (Tai Po District) have also put up some warning signs warning against damage. The government departments replied to us in a joint letter in September, saying no one has admitted responsibility so no further action can be taken.
This event highlights the problem of regional conservation. Under a statutory plan, Yuen Tun Ha is a Green Belt zone, which means even small scale developments are restricted by the Town Planning Board. Yet when dealing with destruction that does not directly result from developments, the Forests and Countryside Ordinance is referred to instead, and this is more difficult to enforce. In order to prosecute the offenders, authorised officers would have to witness the removal or destruction of trees, so there is no accountability for incidents such as at Yuen Tun Ha.
Because of enforcement difficulties, the ordinance lacks a deterrent effect, leading to more damage. Butterfly Surveyors also found that a large Lychee tree was felled at She Shan, in Lam Tsuen, Tai Po District. This tree was a food plant for many butterfly caterpillars. The incident proved that the damage in the countryside is by no means a one-off event. As such damage is usually on a relatively small scale, people may hardly notice. However, as local biodiversity gradually dwindles, the original ecological value will eventually vanish.
This incident received extensive media coverage, and we have since not found any further damage. The vegetation in affected areas gradually recovered, and our Butterfly Surveyors will continue to monitor butterfly ecology at Yuen Tun Ha.