Air Pollution and Biodiversity in Hong Kong
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AUGUST 2003 NUMBER 29 Porcupine! Newsletter of the Department of Ecology & Biodiversity, The University of Hong Kong Air pollution and biodiversity in Hong Kong Nobody doubts that air pollution in Hong Kong is a major threat to human health, and nobody doubts that water pollution in Hong Kong is a major threat to freshwater and marine biodiversity. But what about the effects of air pollution on terrestrial biodiversity? This is an important question because the entire conservation strategy for terrestrial biodiversity in Hong Kong is based on the assumption that protecting areas – as Country Parks, Special Areas, SSSIs or whatever – protects species. Yet, as marine biologists know only too well, pollution does not respect park boundaries. The only research on this problem in Hong Kong was into the effects of sulphur dioxide pollution on lichens (Thrower, 1980). High levels of this pollutant in the 1960s and 70s eliminated most lichens from urban areas and the most sensitive species from the whole of Hong Kong, but sulphur dioxide levels are now declining and there is some evidence of a recovery in lichen populations. Other pollutants, however, are getting worse. Most conspicuous over the last decade has been the regional haze that blankets large areas of southeastern China for much of the year, reducing the amount of sunlight reaching the ground by 5-30% (Chameides et al., 1999). Although this reduction may have serious implications for crop yields, photosynthesis in wild plants is more likely to be limited by water and/or nutrients, so unshaded leaves usually receive more sunlight than they can use. The big worry is ozone (Corlett, 2001). Ozone is unique among air pollutants in that, although it is produced by reactions involving urban pollutants, urban ozone levels are reduced by reactions with nitrogen oxides so that the maximum levels occur downwind of cities, in rural areas (Gregg et al., 2003). Thus ozone concentrations measured at the Hong Kong Polytechnic University monitoring station at Cape D’Aguilar, in the remote southeastern tip of Hong Kong Island, often exceed those measured in urban areas, and the highest recorded hourly value in Hong Kong was in Tung Chung last September. There is no reason to believe that these sites are exceptional, but there has been very little monitoring of ozone in rural Hong Kong. Moreover, while much of Hong Kong’s ozone is generated locally, there are also regional high ozone events, covering much of eastern China, which would impact Hong Kong even if it were uninhabited. Peak ozone concentrations measured in Hong Kong are within the range that has been shown to damage both crops and wild plants in Europe and North America. Ozone reduces photosynthesis and plant growth, as well as causing visible damage to leaves. We have no direct evidence that such damage is occurring locally, but the visible symptoms are easily confused with other forms of natural damage, and no detailed study has been carried out. Regional ozone concentrations are predicted to continue rising for at least the next decade, so this is a problem that can only get worse. Richard T. Corlett (for bibliography see back page) 2 News from DEB Porcupine! As we embark upon yet another academic year at the Univer- sity of Hong Kong, we encounter many new faces: new first- NUMBER 29 year undergraduates in the classroom, and new research postgraduates in the laboratories. In the case of DEB, we are August 2003 lucky enough also to have some new teaching colleagues. Dr Cynthia Yau joined as Assistant Professor this Septem- ber, and an article introducing her will feature in the next Newsletter of the Department of Ecology & issue of Porcupine! And, while not new to exactly DEB, Dr Biodiversity, The University of Hong Kong Kenny Leung takes up a new position as Assistant Professor, also from September. For anyone who missed it, Kenny’s (revealing) personal profile is in Porcupine! 25. "And, INSIDE THIS ISSUE: finally, congratulations to Gray Williams who has been appointed Honorary Director of the Swire Marine Laboratory for the next three years. Gray is not, of course, new to DEB but this appointment will see him taking on an additional, important role on behalf of the department. We wish him Air pollution and biodiversity in Hong Kong 1 luck.” Editorial 2 More newness: DEB, AFCD and Friends of the Country Park DEB news 2 have just published a series of four field guides to local habitats. First off the block was Rocky Shores and Hill- Feedback 3 streams, and by the time you read this, Hillsides and Sandy Invertebrates 5 Shores will have joined them on the shelves of Hong Kong Vertebrates 8 bookshops. All four volumes are bilingual, well- illustrated, and contain gazetteers for sites of interest. We hope they Flora 13 will be of value to secondary school students, teachers, SWIMS tidings... 14 biology undergraduates, and members of the public who want to find out a bit more about Hong Kong’s rich Diversity at a glance 14 biodiversity. Miscellany 16 Finally, new from Government is recently released and very In the News 18 long awaited Consultation Document entitled Nature Wild Corner 19 Outlook: A Review of Nature Conservation Policy (http:// www.etwb.gov.hk). It sets out conservation efforts and Recent publications 21 achievements of Government, describes their limitations, and makes some proposals for improvement that include the Editorial introduction of a scoring system for assessing ecological value of sites, and options for conserving ecologically impor- Colour coding – have you noticed that when an unpalatable or tant sites under private ownership. The sharp-eyed reader difficult conservation viewpoint is expressed, the apparent offender may note that this brief description of the contents of Nature is often glibly dismissed as being a ‘green’ (or even a greenie)? Outlook doesn’t seem to include anything on actual policy This is becoming a rather convenient retort to dodge what are (see pp.16 & 17), and the marine environment also gets short generally rather complex issues, ones that typically require shrift. However, Government has invited comments on the informed responses, creative thinking and pose real and important document, and I urge everyone with an interest in the protec- challenges to government and society. This easy let-out ignores the tion of the Hong Kong environment to read the document fact that there are many shades of ‘green’, from the rather extreme and send their views by October 18 2003 to the Environ- ‘environment above all else’ to the wholly practical, and very real, ment, Transport and Works Bureau. They can be need to balance man and nature for the benefit of both. It is time, reached at [email protected], 2138 3221 (fax) or maybe, to assign a colour to those who do not want to address core 2150 7144 (phone). There now an important opportunity issues, who procrastinate, are uninformed maybe, or who, all in all, to have an input into conservation initiatives in Hong Kong, continue to contribute to the environmental problems that surround and we should make the most of it. us simply by lack of action and obfuscation. In mulling this over, I concluded that ‘grey’ was rather fitting. The lack of colour reflects the absence of action, the distorting (sometimes) of truth, apathy David Dudgeon and general unwillingness to consider changing the status quo or meeting challenges. While there are shades of grey, few give much hope that things will improve substantially in the near term. We could do with more colour. YS 3 swollen bellies have been observed. We have also observed many large adult fish tussling for territory at the artificial reef Feedback aggregation and noted courtship behaviour, including fin and tail flicking towards dusk. For these reasons we reported the ‘Sexed up’ fish data presence of a spawning group of Coral trout. During new moons on 31st May 2003 and 30th June 2003, 35-50, mostly Dear Feedback, 16”-22”, Coral trouts were again counted within a small area at the aggregation site (which is the same artificial reef site As the author of the Artificial Reefs and Reef Fish in Hong each year) and a male spawning rush was observed. We also Kong I must respond to the comments made in Andy pointed out on page 43 that recruitment of juvenile Coral trout Cornish’s review of this book in the April 2003 Porcupine!. has dramatically improved since 2000 when we first observed The first printing of this book involved the production of a spawning groups on an artificial reef. Following the limited number of books, which have already sold out. For the publication of the book we have also filmed pairs of Red second edition, which is currently in preparation, we are groupers, Epinephelus akaara spawning at the same attending to any errors identified and are taking the aggregation site. opportunity to update the book. An erratum for the first has been prepared and will be posted on AFCD artificial reef web Reef fishes are especially vulnerable during spawning pages. I am grateful to the reviewer for his helpful fish aggregation periods. Despite its status as a Marine Park there identification comments. The reviewer’s comments regarding is no statutory protection for Yan Chau Tong’s spawning the making of unsubstantiated claims regarding spawning groupers from licensed fishers. The artificial reef in question observations in the book are, however, entirely unjustified. It has developed into a primary aggregation site for spawning appears we are being accused of ‘sexing up’ our data in much reef fishes in Hong Kong and concerted efforts should be the same way the BBC have alleged that Tony Blair’s made to protect the site, especially during May and June new Government overstated the case to the British Parliament for moons.