NEW ZEALAND’S BAR‐TAILED GODWITS and RED KNOTS DEPEND ON THE YELLOW SEA Bar‐tailed Godwits at the Yalujiang National Nature Reserve, China The Ornithological Society of New Zealand New Zealand hosts internationally important populations of Bar‐tailed Godwits (c.100,000) and Red Knots (c.30,000 1 ) during the non‐breeding season. Bar‐tailed Godwit Limosa lapponica baueri Breeds in Alaska; spends the non‐breeding season in New Zealand and eastern Australia. Bar‐tailed Godwits migrate from New Zealand to the Yellow Sea non‐stop (Figure 1) – a journey of some 10,000 km that takes about 7 days and nights 2 . Tracks of satellite‐tagged Bar‐tailed Godwits on northward migration 3 . Before migrating from New Zealand godwits will double their weight. They spend 30‐50 days 4 in the Yellow Sea where they again increase their weight before the c.6,000 km flight to Alaska that takes 4.5 days and nights 5 . Bar‐tailed Godwit at Manawatu estuary, New Zealand L Recently arrived, 2 October, thin and emaciated. R The same bird prior to northward migration, 19 March, very plump. [Photos: Jesse Conklin] Red Knot Calidris canutus rogersi and piersmai Piersmai breeds on the New Siberian Islands and rogersi in eastern Siberia; both spend the non‐breeding season in New Zealand and Australia. At least some New Zealand birds pass through northwest Australia en route to the Yellow Sea. At least some make the Australia‐
Yellow Sea journey in a single flight 6 . The Yellow Sea – a vital stop‐over, but for how much longer? Most Bar‐tailed Godwits and Red Knots migrating from New Zealand have a stopover in the Yellow Sea on northward migration. Here the intertidal flats with their rich supply of benthic invertebrates provide the necessary resources for the birds to refuel before flying to their breeding grounds. The Yellow Sea An abundance of Potamocorbula laevis provides a rich food supply for both Bar‐tailed Godwits and Red Knots at Yalujiang and Tangshan Remote tracking indicates that about 70% of all Bar‐tailed Godwits from New Zealand stopover at the Yalujiang National Nature Reserve, Liaoning, China 7 . In 2007 the boundary of the nature reserve was adjusted, thereby excising 7,557 ha, to facilitate the expansion of Dandong Port which included reclamation of intertidal flats. Yang et al. (2010) suggested that over 45% of the total East Asian‐Australasian Flyway population of Red Knots stopover in the Tangshan area of Bohai Bay 8 , but recent work indicates that it is in excess of 75% 9,10 . The intertidal area of Bohai Bay has been severely reduced by extensive reclamation in recent years 11 . Detailed studies in Bohai Bay have demonstrated how numbers of Red Knots have apparently increased as the area of available habitat has been reduced through land claim. Red Knot peak number
in study sites Tangshan (x1000)
80
70
2010
60
50
2009
40
30
2008
20
2002
2004
2006
2007
10
0
2002
2004
2006
Year
2008
2010
650
600
550
500
450
400
Available mudflats in W and N Bohai Bay (km2)
Red Knots at Tangshan, Bohai Bay – numbers increase as the area of habitat decreases – birds are forced into the remaining habitat 12
350
The scale of reclamation in the Yellow Sea is hard to imagine from a New Zealand perspective. Between 1994 and 2010, 450 km2 (including 218 km2 of intertidal flats) were reclaimed for two industrial projects in Bohai Bay alone 13 , and it is claimed that cutter‐
suction dredgers can discharge 3,500 m3 of sand per hour ‘and turn one square kilometre of water into land every month’ 14 .The Caofeidian development in Bohai Bay anticipated that ‘The reclamation area will be 105 km2 in 2010, 150 km2 in 2020 and 310 km2 in 2030. This is the largest single coast reclamation project for land formation in the world’ 15 . The Chinese State Oceanic Administration’s general plan for reclamation in Liaoning Province for the year 2011 was for 30 km2 while the six coastal cities in the province planned to reclaim 1,000 km2 16
. Nationally China expects to reclaim >500 km2 per annum in the period 2009‐2020 17 ‐ the intertidal area of the Firth of Thames Ramsar Site covers some 85‐90 km2 18 , while that of the Farewell Spit Ramsar Site is about 100 km2 19 . China and South Korea, in November 2009, endorsed a recommendation that governments should enforce strict limits on new coastal reclamation, which was included in the Strategic Action Programme for the Yellow Sea Large Marine Ecosystem 20 . The issue of coastal reclamation was also highlighted by the China Council for International Cooperation on Environment and Development (CCICED) report on Ecosystem Issues and Policy Options Addressing Sustainable Development and China’s Ocean and Coast 21 and their policy recommendations included the development of a national strategy or plan on marine ecological protection which should ‘prioritize such issues as sea enclosure and land reclamation’ 22 . Notwithstanding central government’s concerns about the need to control coastal reclamation, in 2009 the China Daily reported 189 km2 of illegal reclamation, with ‘61 of the 62 cases being conducted by governments and port holdings’ 23 . Reclamation of intertidal flats in the Yellow Sea remains the most serious threat facing New Zealand’s Bar‐tailed Godwits and Red Knots. The continued loss of foraging habitat could result in birds being unable to reach departure threshold weights, with severe fitness and survival consequences, as has been found for other populations of Red Knot suffering a major reduction in food availability 24, 25 , 26 . It has been suggested that the loss of the intertidal staging area at Saemangeum, South Korea has resulted in a significant reduction in the global population of Great Knots Calidris tennuirostris 27 . The IUCN World Conservation Congress, to be held in South Korea in September 2012, provides an opportunity to support national governments in their efforts to sustainably manage these resources. There are 2 motions for consideration: • Motion 32 ‐ Conservation of the East Asian‐Australasian Flyway intertidal zone, with particular reference to the Yellow Sea and its threatened birds. • Motion 66 ‐ Improving conservation and sustainability of the Yellow Sea. 1
OSNZ. 2012. http://osnz.org.nz/sites/osnz.org.nz/files/2011%20Wader%20Census%20Report.pdf (accessed 11 June 2012) Battley et al. 2012. Journal of Avian Biology 43: 21‐32. 3
Battley et al. 2012. loc. cit. 4
Conklin et al. 2010. Nature Communications DOI:10.1038/ncomms1072 5
Battley et al. 2012. loc. cit. 6
Global Flyway Network unpublished
7
P.F. Battley & J. Conklin unpublished. 8
Rogers et al. 2010. Emu 110: 307‐315. 9
Rogers et al. 2010. loc. cit. 10
Hassell et al. 2011. Red Knot northward migration through Bohai Bay, China, field trip report April & May 2011.Global Flyway Network 11
Yang et al. 2011. Bird Conservation International 21: 241‐259. 12
After Yang et al. 2011. loc. cit. 13
Yang et al. 2011. loc. cit. 14
Caofeidian: industrial zone ‘built on sand’. http://www.china.org.cn/english/China/216868.htm (Accessed 12 June 2012) 15
China Communications Construction Company Ltd. Land formation project by coast reclamation in Caifeidian Industrial Area. http://en.ccccltd.cn/business/dredging/201011/t20101112_1537.html (Accessed 12 June 2012) 16
China Daily 12 August 2011. http://www.chinadaily.com.cn/cndy/2011‐08/12/content_13097245.htm (Accessed 11 June 2012) 17
Anon. 2010. Ecosystem issues and policy options addressing sustainable development of China’s ocean and coast. China Council for International Cooperation on Environment and Development. http://www.cciced.net/encciced/policyresearch/report/201205/P020120529358302221866.pdf (Accessed 22 July 2012) 18
Battley & Brownell 2007. Auckland Regional Council Technical Publication 347. 19
Battley et al. 2005. Marine Biodiversity Biosecurity Report 7. 20
UNDP. 2009. Strategic action programme for the Yellow Sea Large Marine Ecosystem. http://www.yslme.org/pub/SAP.pdf (Accessed 11 June 2012) 21
Anon. 2010. loc. cit. 22
http://www.cciced.net/encciced/policyresearch/recommendations/201205/P020120515487317131888.pdf (Accessed 11 June 2012) 23
http://www.chinadaily.com.cn/china/2009‐06/23/content_8311114.htm 24
Baker et al. 2004. Proceedings of the Royal Society B 271: 875‐882. 25
Gonzalez et al. 2006. Hornero 21: 109‐117. 26 Morrison et al. 2007. Journal of Avian Biology 38: 479‐487. 27 Moores et al. 2008. The 2006‐2008 Saemangeum Shorebird Monitoring Program Report. Birds Korea publication, Busan. 2
Bar‐tailed Godwits departing on migration from Yalujiang National Nature Reserve, China 6 May 2012