From moth expert Roger Kendrick – response to anonymous commenter:
This species has been seen three times only, two sightings of single individuals and my record of five adults from Hoi Ha. I've been recording moths in HK since 1994 and have data from almost all significant contributors dating back to the 1960s (over 65,000 records of 2,300 moth species). The world's expert on the group (a Taiwanese Assoc. Professor, Yen Shen Horn, now one of the world's foremost Lepidoptera researchers) identified the species for me. It is undescribed and the known related species (one described from Japan and one undescribed from Taiwan) are mangrove associates whose larvae feed on algae below the water. That the moths at Hoi Ha were recorded on the back of a beach away from the mangrove indicates the moth travels around the areas adjacent to the mangrove to find nectar, thus it is likely that any development close to the beach and back beach areas adjacent to the mangrove will impact upon this species.
There is, of course, a possibility that the HK species occurs elsewhere, but the increasing amount of survey work being done has not yet found it. It has not been recorded at Mai Po or Wetland Park, despite fieldwork taking place at the right time of year. Based on what is known, not guessed, applying the "Precautionary Principle" expounded by the Convention on Biological Diversity and Sustainable Use of Natural Resouces, and using the IUCN Red List Criteria, this species can only be considered to be currently at high risk of extinction due to the small population size, the very limited area of occupancy, the very limited extent of occurrence and the high degree of threat (through habitat destruction of adjacent land and probable ecological impact on the actual site of the moth – the adults appear to need to find nectar from plants on the beachfront, not just within the mangrove).
I agree that there should be debate about looking specifically for each of HK's rare / endemic / globally significant species, and doing as thorough a job as possible on their ecology. However, where there is data on a HK species of global significance, however limited, don't you think it's better to flag up the issue rather than to let it be lost, knowing that you had it within your reach to make a difference and raise the awareness of the conservation issue?
The moth in this case is being used as a flagship to highlight general environmental damage – Hoi Ha is recognised for its landscape appeal. The problem with the current HK planning system is that it looks at each planning application as a stand alone proposal, without looking at the cumulative effect that (as in the Hoi Ha case, for example) many new houses would have. I am sure you are aware of this issue. I would love to be able to go and find extra colonies of the moth species in question, but as I'm an independent researcher, unless someone is willing to sponsor me financially to go and survey every mangrove in HK and some of the mangroves adjacent to HK (what's left of them), I can only use what data currently exists.
Conservation has to be a pragmatic mixture of academic and practical approaches to get any results on the ground (or in the air or water). I can't wait another 3 or 4 years for a full survey of the species, only to find that the mangroves and shore vegetation around Hoi Ha, Tai Mei Tuk and so on have been lost, whilst the survey is underway. Hong Kong has already lost too much through inaction. If my actions make people in Govt sit up and take notice that there are people who are concerned about the planning process and its effect upon wildlife in HK, then so much the better. Have you asked yourself why Govt still haven't told the HK public properly that HK is now a signatory to CBD? If they wont, then it's up to us in the NGO and voluntary sectors to bridge this gap.
I have cc'd this reply to a number of people around the world who are involved in conservation, either as academics, or through the Govt. / NGO / voluntary sectors. I'd welcome any opinions on the direction the NGO / voluntary sectors should be going in HK. I look forward to all of us in HK getting a better understanding of how we should try and make a better case of conservation in HK.