As villagers recall, Fu Tei Au was once inhabited by large numbers of fireflies. Over the last 50 years, however, their populations have greatly diminished due to rapid development of infrastructures and factories, such as the Sheung Shui Treatment Works located towards the end of the village, K. Wah asphalt plant next to Man Kam To Road, Sheung Shui Slaughterhouse and Sewage Treatment Plant to the west of Ng Tung River. While the Water Pollution Control Ordinance is able to maintain optimal water quality level in respect of discharges from new structures, landscape alteration may nonetheless cause habitat fragmentation and food web deconstruction, reducing the mobility and reproductive ability of living organisms that live depending on the integrity of the ecosystem. In respond to the staggering decline in firefly numbers, villagers have volunteered to observe their activities regularly and organize tours for people to watch and understand more about this special insect. Species such as "Mountain Firefly" (Lychnuris praetexta) and aquatic firefly were spotted around the meander listed as conservation area near Ng Tung River.

Do you know?
Fireflies produce intermittent light by way of bioluminescence – a combination of oxygen and a compound called luciferin in their abdomens. They prefer warm and humid environments near streams, marshes, fields, and forests etc. A region’s overall cleanliness and water quality play important roles in determining its attractiveness to fireflies, making these tiny lightning bugs a biological benchmark for favourable environment.