How many of the world's species are to-dateinformation on populationtrends is an essentialbasis declining, and where are the Globally Threatened for identifyingpriorities for conservationaction. This paper species? presentsthe results of a major collation and reanalysis of 1990s migratory wader populationdata for all countriesin Simon Delany Africa and Eurasia. Wetlands International; This review was carried out by the InternationalWader e-marl: Simon.Delany @wetlands. org StudyGroup between 1996 and2000. It updatesprevious es- timatesdating from the mid-1980s. We presentstatus infor- The publicationby WetlandsInternational in 2002 of Water- mation on 115 populationsof 49 species.Of thesewe have PopulationEstimates - third edition (WPE3) involved beenable to give sizeestimates (to varyingprecision) for 110 wide consultationwith population experts and provides a populations,1% populationthresholds (or provisionalthresh- usefulstarting point for the evaluationof numbersand popu- olds) for 102 populations,and indicationsof trendsbetween lation trendsof the world's waterbirds.About one quarterof the mid 1980s and mid 1990s for 70 populations.Compari- the speciesrecognised as "waterbirds"by WetlandsInterna- sons between flyways show that data quality is best for tional are ,and informationis presentedin WPE3 on populationsusing the largely coastalEast Atlantic Flyway, all 209 of the world's waderspecies. Estimates are now avail- than for other flyways in the region:it has beenpossible to able for a majority (85%) of the world's waderpopulations, assessprecise trends for 78% of East Atlantic Flyway but populationtrends have only been estimatedfor 41% of populations,but for only 43% of the Black Sea/Mediterra- populations.At the global level, theseknown trendsbreak nean populationsand just 5% of West Asian/EastAfrican down asfollows: Increasing, 13%; Stable,39%; Decreasing, populations.It is difficult to draw conclusionson the over- 44%; Extinct, 4%. all statusof waders in Africa/Eurasia, since reliable estimates A total of 44 species(21% of all wader species)are rec- of population trends can be made for only 44 of the 115 ognisedas Globally Threatenedor Near-Threatenedunder populationsusing the region. There are, however, 2.5 times IUCN Criteria. A disproportionatenumber (72%) of these as many populationsin declineas thosethat are increasing: Globally Threatenedspecies have rangesof distributionin thereis a decreaseor possibledecrease in 20 populationsand Asia and Oceania. A high proportion (66%) of Globally an increaseor possibleincrease in eight, with 36 being sta- Threatenedspecies are sedentary,and a majority of these(21 ble or possibly stable. Furthermore,some populations are out of 29 species)are specialisedisland forms. Red Data lists known to be severelythreatened and in decline,notably Slen- producedby BirdLife Internationalon behalf of IUCN are der-billedCurlew Numeniustenuirostris and SociableLap- compiledat the specieslevel; more threatenedwader popu- wing Vanellusgregarius, and the two Canary Islandsraces lationswould be identifiedas deservingof conservationac- of Stone Burhinus oedicnemus. tion if theselists were compiled at the level of sub-species A review of progressin improving data and information or biogeographicpopulation. showsthat there has been significantimprovement with re- Most, but not all, Globally Threatenedspecies are known spectto some populations(especially knowledge of Euro- to be in decline, and Globally Threatenedspecies represent pean distribution of breeding waders and their population just underhalf of speciesknown to be in decline.Because of trends,particularly in the MediterraneanBasin and in Rus- specialefforts to identify and conserveGlobally Threatened sia). However, very little progresshas been made for many species,and because less numerous species are usually easier other priority areas,such as waderswintering on non-estua- to monitor, our informationabout populations and trendsis rine coastsor inland. Indeed, for 62 populations (57% of biasedin favour of globally threatenedspecies. Many other those considered)monitoring provision is not adequateto speciesand populationswhose trend is unknownat present provide even the most basic informationon trendsin abun- are likely to be declining,and expansionand refinementof dance.Only in 16 populations(15%) is there a soundbasis monitoringis necessaryto identify relatively numerousand for assessingchanges in populationsizes. For the remaining widespreadspecies which are neverthelessdeclining. 30 (28%) populations,monitoring provides some informa- tion althoughthis is usually far from adequatein extent or quality. For no biogeographicalpopulation is it currently Status of migratory wader populations in Africa possibleto assesstrends with any defineddegree of statisti- and Western Eurasia in the 1990s cal precision.This lack of monitoringprovision is a serious conservationdeficiency given not just the need to assess David Stroud, N.C. Davidson, R. West, D.A. Scott, population change at local and country scalesbut also to L. Haanstra & O. Thorup assessthe potential major impactspredicted from a chang- UK Joint Nature Conservation Committee, Monkstone ing globalclimate. The African-EurasianWaterbird Agree- House, City Road, Peterborough,UK; ment has highlightedmonitoring as a major priority for the e-marl: David.Stroud @jncc. gov. uk internationalconservation of waterbirdswithin the region. We hope this review will stimulateconcrete urgent actions Estimatesof the size of wader populationsneed to be regu- to this end. larly updatedfor usein flyway andsite conservation, and up-

13 Bulletin 101/102 August/December 2003 14 Wader Study GroupBullehn

Status of wader populations on the Central/South Population trends: There is very little information on Asian flyway trendsin populationsize for the CentralAsian flyway. WPE3 Nick Davidson gives trendsfor only 14 populations(20%), and there is a "definitetrend" for only 12 of these(17%). Trend informa- Chemin des Jordils, 1261 Le Vaud, Switzerland; tion is availablefor only 2 (12%) of residentpopulations, of e-maih linda @iprolink. ch these,one is decreasingand the other stable.Overall, 50% of populationswith known trendsare decreasing.Four mi- Flyway characteristics: The Central/SouthAsian flyway gratorypopulations are increasing,but for two of these,the coverswader populationsbreeding in the central Siberian long-distancemigrants Black-tailed Limosalimosa arctic,boreal Russia and the centralAsian steppe(long and andRed-necked Stint Calidrisruficollis, only a smallpart of medium-distancemigrants), with short-distancemigrants and the relevant populationwinters on . residents breeding south of Himalayan mountain chain. Furthermore,the increasingtrend is not certainfor the short- Under currentpopulation delimitations there is considerable distancemigrant White-tailed Lapwing Vanellus leucurus. overlap of migratorypopulations with the West Asian/East Only one population(Pied Avocet Recurvirostraavosetta) African flyway and somewith the East Asian/Australasian wholly dependenton the flyway is increasing.It seemsthat flyway. The staging areas for long and medium distance perhaps3-4 times as many populationson the flyway are migrantsare poorly known, but are believedto be chiefly decreasingas are increasing. inland freshwater and saline wetlands in Central Asian coun- Globally threatened speciesand populationsof conser- tries. Wintering areasare mostly coastalintertidal wetlands vation concern: There are six Red Listed specieson the from Pakistaneast to , andit is possiblethat some flyway, from differentbreeding areas, with differentmigra- birdscontinue on to IndianOcean islands. Major coastalwin- tory strategies(resident to long-distancemigrant), and using tering areasinclude the Indus Delta (Pakistan)and the NW differentwintering habitats. These are the Critically endan- Indian coast,the SW Indian/N Sri Lankan coast,the Bang- gered residentJerdon's CourserRhinoptilus bitorquatus; ladeshcoast and probablydeltas on the coastof Myanmar. endangeredNordmann' s GreenshankTringa guttifer (medium- This is the shortestof all wader flyways, lying wholly north distancemigrant); the vulnerableWood of the Equator. nemoricola(short-distance migrant), SociableLapwing V. Number of speciesand populations:The flyway analy- gregarius (medium-distancemigrant) and Spoon-billed sesare derived from Waterbird Population Estimates3rd SandpiperEurynorhynchus pygmaeus (long-distance mi- Edition (2002) (WPE3). There are 59 wader specieson the grant,now believedto be in seriousand rapid decline - see flyway, of which49 aremigrant or partlymigrant ("migrant" the abstractof Tomkovich& Syroechkovski);and the near- includesspecies/populations with partlyresident, partly short- threatenedAsiatic DowitcherLimnodromus semipalmatus distancemigrant status), and 10 arewholly resident. There are (medium-distancemigrant). There are 14 populationsof 7 ! biogeographicpopulations of which54 aremigrant and 17 "conservationconcern" (i.e. <25,000 birdsand/or in decline). resident.In termsof numbersof speciesand populations, this Theseinclude the populationsof the six globallythreatened is a considerablymore diverse flyway in comparisonwith any species.In addition, the Long-billed Plover Charadrius of the African-Eurasianflyways. The flyway is dominatedby placidushas a small, (<10,000 birds) decliningpopulation ploversand (63% of populations).Many (47%) of that shouldbe consideredfor Red Listing. Six otherpopu- the residentpopulations are plovers.44% of migrantpopu- lations are small, but of unknown, trend and one (Grey- lationsare calidridand tringid sandpipersand their "allies", headedLapwing V. cinereus)has a larger populationbut is with a further24% beingplovers. in decline.Overall, at least20% of flyway populationsare Population sizes:WPE3 includespopulation size esti- of conservationconcern and, given the poor stateof recent matesfor 56 populations(79% of the total). Theseinclude knowledge,this figure may be muchhigher. estimatesfor 49 (91%) of migratorypopulations, but only 7 Conclusions:The Central/SouthAsian flyway is a rela- (41%) of the residentpopulations. However, preciseesti- tively shortflyway, with high diversityof waderspecies and mates(i.e. not just a range) are made for only 38% of mi- populationsbut with rathersmall population sizes. Popula- grants and just 18% of residents.Furthermore many esti- tion status,both sizesand especiallytrends, is very poorly matesare old (pre-1990s),and the main sourcein WPE3 is known and much of the available information is at least 10- still Perennouet al. (1994) which coversdata from 1987-91 15 yearsold. Residentpopulations are particularlypoorly (51% of populationestimates; 36% of trend estimates).In known. Analyses of WPE3 information for this flyway addition, another20% of WPE3 populationestimates are shouldbe treatedwith caution,and no time-periodassess- from as yet unpublishedsources. Current population status mentof changein populationstatus is possible.However, on is very poorly known. Accepting these limitations, most availableevidence, it appearsthat the wadersdependent on (80%) of migratory populationsare in the range 25,000- thisflyway have a decliningstatus: very few populationsare 1,000,000 and only 18% are <25,000 birds. Resident increasing,and others (possibly around 3-4 timesas many) populationsare mostly smaller, with 57 % each <25,000 are in major decline.Declining populations come from dif- birds.The total estimatedCentral Asian flyway waderpopu- ferentbreeding areas. There is anurgent need to fully update lation is approx.9.4 million wadersfor 80% of the popul- Perennouet al. (1994) before WPE4. This can be achieved, ations,suggesting that the total populationis around11 mil- at leastin part, througha completeanalysis of Asian Water- lion birds. For migratory populationsonly, there are 8.6 bird Censusdata in order to yield updatedsize and trend million wadersfor 91% of populations,suggesting an esti- estimates. There is also a need to understand more about the mated total of about 9.4 million birds. This is small in com- ecologicalstatus (particularly changes and threats)of the parisonwith severalother flyways (e.g. East Atlantic 14.4 Central Asian breeding and stagingareas, and the major million; Black Sea/Mediterranean 25.9 million; West Asia/ coastal wintering areas. In particular, is the increasing E Africa 22.8 million (Stroud et al. 2003)). droughtin CentralAsia affectingbreeding and staging area

Bufferin 101/102 August/December 2003 Cad•z conference 15

suitability?In a regionof largecoast-dwelling human popu- The status of shorebird populations in Oceania lations,to what extentare coastalwintering areas under pres- RobertGill, Jr. 1, Ray Pierce2, AdrianRiegen 3, Lee sure from land-claim, mangrove destruction and other Tibbitts • & Oscar W. Johnson 4 wetland habitat degradation? 1. U.S. Geological Survey, Alaska Science Center, 1011 E. Tudor Rd., Anchorage, Alaska, USA, The East Asian-Australasian Flyway e-mail RG: robert [email protected]; e-mail L T: Jim Wilson [email protected]; 2. WildlandsConsultants Ltd., 112 Bank St., PO Box 1305, Whangarei, New Zea- Granveien 46, 1911 Flateby, Norway; land, e-maih [email protected]. nz; 3. 3231 Forest Hill e-marl:jim wils@ frisurf. no Road, Waiatarua, Auckland 8, New Zealand, e-maih [email protected]. nz; 4. Dept. of Ecology, There are estimated 7 million waders in the East Asian-Aus- Montana State University, Bozeman, Montana, USA, tralasianFlyway. There are 102 species.Five of thesebreed e-maih owjohnson2105 @aol. com in NE Siberiaand migrateto SouthAmerica. One breedsin the sameregion (Ruff) andmigrates to the southwest.Of the Oceania, including here New Zealand but excluding Aus- remaining94 species,41 are residentsand 53 migrants.19 tralia, supportsa lower diversityof shorebirdsbut propor- (46%) of the residentsare classifiedby IUCN as Globally tionatelymore taxa of conservationconcern than any other Threatened.Four (8%) of the migrantspecies are classified, region of the globe. Eight of 13 (62%) residenttaxa have two as near threatened, one as vulnerable and one as endan- beenassigned an IUCN threatstatus, including one as Criti- gered. cally Endangered(Black Stilt Himantopusnovaezlandiae), Causesof declinesin residentspecies are habitat loss, four as Endangered(Tuamotu SandpiperProsobonia can- predation,small islandpopulations and human disturbance cellata,Chatham Oystercatcher Haemantopus chathamensis, (on beaches).The main threatto migrantspecies is perceived New Zealand Dotterel Charadrius obscurus, Shore Plover ashuman population pressures on the stagingareas in Asia, Thinornisnovaeseelandiae), and three as Vulnerable (Wry- especiallyaround the Yellow Sea.Birds migrate through an bill Anarhynchusfrontalis, New Zealand Snipe Coenocor- areaof the world that containsone third of the humanpopu- ypha aucklandica,Chatham Snipe C. pusilla). The Hawai- lation. This creates an enormous demand for use of wetlands ian Stilt Himantopusknudseni is listed asEndangered by the for humanbenefit, to the detrimentof waders.For example United States. Populationsizes of the nine listedspecies are the Saemangeumreclamation project will removeone of the mostly under 2,000 individuals, with thoseof Black Stilt, world's most importantstaging sites used by 18 speciesin ChathamOystercatcher, and ShorePlover numbering200 or numbersof internationalimportance, including 31% of the fewer. Encouraginglythough, for the HawaiianStilt andall world populationof Great Knots tenuirostris. New Zealand endemicshorebird species, with the possible Monitoringhas been carried out on non-breedingareas in exceptionof the BandedDotterel, populationtrends are in- Australiaand New Zealandwith the longestrunning scheme creasingor stable due to concertedconservation efforts. datingback to 1968. In Australia,there is only goodquality Numbersof Tuamotu Sandpipersappear to be decliningbut long-termmonitoring in the southeastand this showsvery its statusis unclear over large portions of its range. An large declinesin somespecies over the last 10 years.How- equally small numberof Palearctic-and Nearctic-breeding ever,these declines may not reflectthe situationthroughout specieshas developedvarious specialized migration strate- the non-breedingranges. Changes in climate may causea giesin whichpopulations (in wholeor in part) spendthe non- northwardshift in the non-breedingrange as the remaining breeding seasonin Oceania. Of these, the Bristle-thighed partsof the Yellow Sea, which is mostlytoo cold in winter, CurlewNumenius tahitiensis is the only specieswhose entire becomesmore availableas a non-breedingsite. Monitoring population(<10,000 birds and listed as Vulnerable) occurs is also carried out at migration sitesin Hong Kong, South exclusively in Oceania during winter. About 90% of the Korea and Japan. Wandering Tattler Heteroscelus incanus population and Annual breeding successis monitored in SE and NW probably more than 50% of the Pacific Golden-Plover Australiaby catchingvery largenumbers of birds.Attempts Pluvialisfulva populationreside in Oceaniaduring the non- have not been made to measure breeding success from breedingseason. Other migratorytaxa for which habitatsin comparisonbetween non-breeding season counts and the Oceaniasupport varying fractionsof their entire or subspe- numbers of immature birds remaining in Australia in the cific populationsinclude Ruddy Arenaria i. inter- northernsummer. However, data do existto explorethe pos- pres,Grey-tailed Tattler H. brevipes,and Sanderling Calidris sibilitiesof usingcounts as a methodof measuringbreeding alba. Despitethere being little trendinformation for migrant success. shorebirdspecies inhabiting Oceania, a single paramount Conservationplans are in place for threatenedspecies in issueargues strongly for close vigilance for their welfare Australia and New Zealand. There are also international among all regionsof the planet: human-causedextinctions agreementswithin the flyway, for examplebetween Japan or extirpationsof residentavian populationshave been, and and Australia (JAMBA) and between and Australia continueto be, mostprevalent in Oceania. (CAMBA), and a shorebirdsite network has been developed underthe Asia-Pacific Migratory Waterbird Conservation Strategy.All this has led to an increasingunderstanding of wetlandsand international cooperation within the flyway, but thereis still a lack of data from many areas.

Bulletin 101/102 August/December 2003 16 Wader StudyGroup Bullebn

Shorebird Populations in North America: probablybecause of theirlife historiesand high dependence Numbers and Trends on key stopoversites during their long migratoryjourneys. In some areas, shorebirds have to face conservation threats R.I.G. Morrison from pollution,tourism and development,water manage- Canadian Wildlife Service, National Wildlife Research ment,habitat changes from livestockand agriculture. Urgent Centre, Carleton University, 1125 Colonel By Drive cooperativeresearch and monitoring are neededto support (Raven Road), Ottawa, Ontario, Canada K1A OH3; conservationinitiatives throughout the NeotropicalRegion e-mail: Guy.Morrison @ ec. gc. ca before it is too late.

Informationon populationsize is reviewedfor 53 speciesof shorebirdsthat occur in Canada and the USA, and an outline Breeding waders in Europe: a year 2000 assess- givenof the typeof dataused to derivethe estimates.Popu- ment of population sizes and trends lation sizesrange from a few tens to severalmillions, with Ole Thorup most falling in the low hundredsof thousands.Estimates currentlytotal some27.5 million shorebirds.Most estimates Wader Study Group, Vester VedstedByves 32, are consideredto be of low accuracy,though detailed infor- Vesterd Vedsteo, DK-6760 Ribe, Denmark; mationis availablefor a few speciesthat have beenthe sub- e-mail: olethorup@post. tele. dk ject of specialinvestigations. Delivery of comprehensive shorebirdmonitoring requirements outlined in the Canadian The Wader StudyGroup project "Breeding Waders in Eur- and US Shorebird Conservation Plans has led to the forma- ope 2000" compiledup-dated population estimates from 52 tion of PRISM, the Programfor Regionaland International countriesand regionsin Europe, including Greenlandand ShorebirdMonitoring. The main elementsof PRISM, which northeastCanada. Of 69 Europeanbreeding populations includesurveys on breeding,migration and winteringareas, there are reasonablygood quality breedingdata for 35. But are outlined.Recent analyses of shorebirdpopulation trends due to lack of repeatedsurveys, it is not possibleto assess suggestthat many species are declining,especially long-dis- trendsfor a numberof these.It is thusnot possibleto assess tance, Arctic-breedingshorebirds passing through eastern trendsfrom breedingestimates in most of the large wader Canada and the North Atlantic states of the USA. Several populationsin thearctic and boreal parts of northernEurope. case studies are reviewed. On the other hand, trends can be assessedfor most wader populationsbreeding further south. In general,wader popu- lationsbreeding in wetlandsare increasingor stablein the Are Shorebirds in Decline in the Neotropical westernhalf of Europewhile the situationis morevariable Region? in the easternhalf. In contrast,waders breeding in steppe Patricia M.Gonzalez 1 & Daniel E. Blanco 2 habitat, in wet grasslandand other farmland habitatsare de- clining all over Europe.According to this compilation,12 1. FundacidnInalafquen, P. Moron 385 (8520) San Europeanwader populations are of particularconservation Antonio Oeste, Argentina; 2. Wetlands International, concerndue to very smallpopulations and/or rapid popula- 25 de Mayo 758 10 1 (1002) BuenosAires, Argentina; tion reduction.The majority of the most vulnerablebreed- e-mail: pa triciag@ canaldig. com. ar ingpopulations are confined to steppehabitat (8 populations) or meadowsand pastures(3 populations). To answer this question we used data sourcesfrom the Neotropical Waterbird Census- The First 10 years, 1990- 1999, Waterbird Population Estimates(2003, WI), scientific Long-range monitoring of the Arctic: past pat- andtechnical publications, grey literature, queries to special- terns and future scope, illustrated by trends in ists,banding programmes and Shorebird Study Groups from migrant wader population sizes in the Western theNeotropical Region. Of the439 shorebirdpopulations in Cape, South Africa the World belonging to the Charadriidae, Scolopacidae, Doug M. Harebottle, Les G. Underhill,Manfred Haematopodidae,Recurvirostridae, Rostratulidae and Thino- Walther & Rene A. Navarro coridae, 100 populations(22.9%) representing60 species (32% of species)are in the Neotropicsand for 51% of these, Avian Demography Unit, Universityof Cape Town, there are no trend estimates available. Rondebosch, 7701, South Africa; Half of the shorebirdpopulations of the Neotropicsfor e-mail: doug @adu. uct.ac. za which there is trend information are decreasing,including one that is probablyextinct while only 2% of them are in- The longest running regular surveys of a wetland in the creasing.However, thesedata are not reflectedin their IUCN southernhemisphere at LangebaanLagoon in the WestCoast threatstatus. In the Americas,Nearctic populations (65%) National Park, where regular midsummer and midwinter are betterknown thanNeotropical ones (33 %) becausemost countsof wadersstarted in 1976.The presentationexamines funding for research,monitoring and conservationcome trendsin populationsizes of migrantwaders at Langebaan fromNorth America where migrating Nearctic species spend Lagoonand at othersites in the WesternCape. It proposes part of the year and their breedingseason. the establishmentof a seriesof non-breedingsites which Nearcticspecies are declining more than Neotropical spe- couldbe usedto monitortrends in populationsizes and con- cies(58% of 33 speciesvs 38% of 16 speciesrespectively) sidersthe qualitiessuch sites would need to have.

Bulletin 101/102 August/December 2003 Cad•z conference 17

Population trends of waders in Sweden and the A recent and sharp decline in numbers of Spoon- monitoring of breeding waders in the north billed Sandpipers Ake Lindstr6m Pavel S. Tomkovich1 & EvgenyE. Syroechkovski,Jr 2 Department of Ecology, Lund University,Ecology 1. ZoologicalMuseum of Moscow State University, Building,S-223 62 Lund, Sweden; Bol. Nikitskaya Str. 6, Moscow 125009, Russia; e-maih Ake. Lindstrom @ zooekol. lu. se e-mail: [email protected]. ru; 2. Instituteof Ecology and Evolution, Russian Acad. ScL, Leninski Prospect 33, I review informationabout population trends in someof the Moscow 117071, Russia; e-mail: rgg @eesjr. msu. ru wader speciesbreeding in (mainly southern) Sweden, or passingthrough Sweden on migration(arctic breeders). The The Spoon-billedSandpiper Eurynorhynchus pygmeus has analysisis basedon two main data sources:1) The Swedish long beenconsidered a vulnerablespecies because of its re- CommonBreeding Bird Census(since 1975) and 2) regular strictedrange (breedingin coastalChukotka and Koryak trapping and observationsat Ottenby Bird Observatory Highlands,northern Far East), specializedbreeding habitat, (since 1946). Data quality rangesfrom good to tentative. and small population (estimated globally at 2,000-2,500 Data are presentedfor 10 out of the 29 wader speciesbreed- breedingpairs in the mid-1970s). Initial indicationsof a ing in Sweden,and for nine wader species(mainly arctic sharpdecline in the breedingpopulation were obtainedin breeding)occurring regularly on passage.Of particularcon- 2000 during a large-scalesurvey of the Anadyr estuaryand cern is that monitoring data for several speciesbreeding in adjacentsea coasts,that gave groundsfor consideringthe the far north is almostcompletely lacking. A new scheme totalpopulation as probably fewer than 1,000breeding pairs. basedon surveyroutes systematicallydistributed over the This effort led to the recommendationthat the speciesbe whole of Sweden was launched in 1996, which covers north- consideredas globally endangered (Tomkovich et al., 2002). ern Swedenmuch better than before. There is now the poten- Subsequentsurveys in 2001-2003 of known and poten- tial to monitormore speciesat their breedinggrounds, for tial breedingareas produced both good and bad news. The exampleEurasian Golden Plover Pluvialis apricaria, Whim- surveysrevealed several new breedinglocations, including brel Numeniusphaeopus, Wood SandpiperTringa glareola what is currentlythe largestlocal population(over 75 breed- and Greenshank T. nebularia. ing pairsnear Meinypilgino; 62ø40'N, 177ø05'E).More dis- couragingly, the 2002 surveysof several sites along the northerncoast of the ChukotskyPeninsula failed to find a Genetic and ecological consequences of near singlesite where numbers had increased or wereeven stable. extinctions (population bottlenecks) of waders The most reliable information that suggestsa long-term Allan J. Baker decline in numbers comes from Belyaka Spit (67ø04'N, 174ø20'W)and nearbyYuzhny Island(67ø05'N, 174ø40'W). Royal Ontario Museum and Universityof Toronto, There, up to 95 displayingmales were countedin the early 100 Queen's Park, Toronto, Canada; 1970s(Kretchmar et al., 1978), but by 1986-1988 the same e-mail: allanb @ rom. on. ca areasupported only 45-51 displayingmales (Tomkovich & Soloviev, 2000), and by 2002 only 18 were counted. Many speciesof waders,especially long-distance migrants Factorscontributing to the populationdecline appearto that now breedin the high arctic, are geneticallyimpover- be low reproductionand decreasedsurvival on stagingsites ished becausethey experiencedsevere population bottle- during migrationsand/or on non-breedinggrounds. Since necksin the Pleistocene.In populationswith small effective Spoon-billedSandpipers are long-lived and highly sitefaith- size, geneticdrift can be more importantthan selectionin ful to breedingareas, and the observeddecline in numbers determiningthe fate of new mutations,and thusthese small is widespread,a prolongeddeclining population trend may populationsare expectedto accumulatedeleterious muta- be due to a severefactor (or factors)that stronglydepresses tions. Genetictheory predictssuch fixed alleleswill reduce either reproductivesuccess or (more likely) adult/juvenile the reproductivesuccess of a speciesand lead to extinction survival.Attempts to identify and localize suchfactors be- unlessnew beneficial mutationsare fixed by selectionand gan in 2003 with the initiation of studieson the species' help restorepart of this lost fitness.Critical effectivesize is breeding ecology, but the more urgent need is for assess- thoughtto be a few hundredindividuals, above which a mentsalong the migrationcorridor and on the non-breeding populationwill persistwithout extinction due to geneticload. grounds. However,this requires approximately a ten-foldhigher cen- suspopulation size because of the variancein breedingsuc- cess and fluctuations in numbersthrough time. In popu- lations suchas those of the Red Knot Calidris canutusrufa which is currentlyundergoing a drasticdecline in numbers due to ecologicallybad conditions,the risk of extinctionis exacerbated.I will review the geneticand ecologicalevi- dencethat jointly indicatewhy the populationis declining, andargue that other species may be in the samerisk category.

Bulletin 101/102 August/December 2003 18 WaderStudy Group Bulletin

Population trends and breeding range dynamics in the late 1990s. Since then numbers have continued to de- in Sociable Plover Chettusia gregaria, Black- clinewith peakDelaware Bay countsof 50,000in 1998drop- winged Pratincole Glareola nordmanni and ping to 32,000 in 2002. In 2003, however, the peak count Caspian Plover Charadrius asiaticus in European suddenlyhalved. Russia At our studysite in the breedinggrounds on Southamp- ton Island in the NW of Hudson Bay, we found that the Anton P. IYano¾& Andrey O. Shubin numberof nestsalso showed a markeddrop from 12 in 2000, Zoology & Ecology Dept., Moscow State Pedagogical eightin 2002 to only two in 2003. The resultsof our surveys University,Kibalchicha 6, building5, Moscow 129278, in the main SouthAmerican wintering areas show a decline Russia; e-mail: [email protected], in the number of knots from 51,225 birds in 2000 to 29,271 andrey shubin@mtu-net. ru in 2002, but no changein 2003 at 30,475 in contrastto de- clinesin Delaware Bay and the Arctic. An analysisof original and publisheddata for the last 20 At present,the reasonfor the suddendrop in numbersin yearsshow a catastrophicdecrease in the breedingpopula- DelawareBay and on the breedinggrounds is unclear.If a tions and breeding ranges of Sociable Plover Chettusia major mortality has taken place, this shouldbecome clear gregaria, Black-wingedPratincole Glareola nordmanniand when the winteringpopulation is countedin January2004. CaspianPlover Charadriusasiaticus in southernEuropean In the meantime, the following hypothesesappear to be Russia. equallyplausible: The currentestimate of the Europeanbreeding population of the SociablePlover is only 10-50 pairs. As a breeding 1. The whole adultpopulation arrived on the E coastof the species,it hasdisappeared from a vastarea of theSaratov and United States, but numbers were lower than usual in Dela- RostovRegions and the Republicof Kalmykia. It has also ware Bay becauseof reducedfood supplies(horseshoe becomerare as a migrant. crabs' eggs). Coupledwith insufficientfood elsewhere The currentestimate of theEuropean breeding population few made it to the Arctic. of the Black-wingedPratincole is 5,000-9,000 pairs.It is 2. Some factor, possibly relating to weather or food, oc- reportedto have declinedsignificantly in variousplaces in curredduring the northwardmigration and half the adults theCis-Caucasus, particularly in theKuma-Manych Depres- failed to leave S America. sion and adjacentsteppe areas. During migration,it contin- 3. A major mortality occurredduring the northwardmigra- ues to be rathernumerous, but significantnumbers are only tion (whether through starvation,disease, pollution or recordedin a limited numberof stagingsites. weather is unknown). The currentestimate of theEuropean breeding population of theCaspian Plover is 200-500 pairs.However, for thelast 20 years,there have been no reportsof confirmedbreeding Austral migration related to arrival time of Red for anywherein southernEuropean Russia suggesting that a Knot Calidris canutus rufa to Northern Hemi- major populationdecline has taken place. sphere The declinesin the populationsof thesethree wader spe- PatriciaM.Gonz•tlez 1, MirtaCarbajal 1, AllanJ.Baker 2, ciesare probably due to humantransformation of steppeeco- Maria E. Echave1, Rub•n Pissaco1 & LuisBenegas 3 systems.However, there are insufficient data to explainwhat has happenedfully. 1. Fund. Inalafquen, P. Moron 385, 8520 San Antonio Oeste, RN Argentina; 2. Royal Ontario Museum, 100 Queen's Park, Toronto, ON Canada; 3. Museo de la Rufa knots: over the edge? Ciudad, Alberdi 555, Rio Grande, TF Argentina; LarryNiles 1, KathyClark 1, AmandaDey 1, MarkPeck, e-mail: pa triciag@ canaldig. com. ar Guy Morrison, Ken Ross, Allan Baker, Patricia Arrival time of Red Knotsat theirlast stopover before reach- Gonzalez, RicardoMateus & HumphreySitters ing the breedinggrounds can be criticalto adultsurvival and 1. NJ Endangeredand Nongame Species Program, recruitment.To establishthe relationshipbetween the phe- 501 E. State St., PO 400, Trenton, N J, 08625-0400, nologyof the australmigration and the arrival time at the last USA, e-marl: Larry.Niles@dep. state.nj. us stopoverin theNorthern Hemisphere, simultaneous censuses weremade from 2000 to 2003 in ArgentinianPatagonia both Red Knots Calidris canutusof the subspeciestufa have one at Rio Grande,Tierra del Fuego,where Knots spendtheir of thelongest migrations of all waders,moving through 120 ø non-breedingseason and San Antonio Oeste, Rio Negro of latitude from breedinggrounds in the central Canadian (= SAO), thefirst main stopoversite. In SAO abdominalpro- Arctic to winter in Tierra del Fuego.Because of concernthat fileswere sampled visually (Wiersma & Pierstoa1995) asan thepopulation has been in substantialdecline, we, andothers, index of body massat arrival in early birds.Arrival and de- haveconducted studies throughout the flyway overthe past parturetimes in SAO wasrelated to arrivalin DelawareBay, 10 years. USA by resighting823 birds colour-bandedin SAO, with As far asis known,almost all tufa makea final stopover different marks for the first and the second half of March in DelawareBay, United States,during their northwardmi- 1998, and 146 banded at the end of March 2003. In both grationin May beforeflying directlyto their arcticbreeding localities scans of colour-banded and non-banded birds were grounds.At aroundtwo weeks,this stopoveris so shortthat made, and data were fitted to binomial models. peak numbersare thoughtto be close to the flyway total. In 2000 and 2001, Red Knots arrived early in SAO by Basedmainly on countsin DelawareBay it is estimatedthat direct flights, and had intermediateabdominal profiles. In thepopulation fell from about150,000 in the 1980sto 60,000 2002, however,Knots left Rio Grande 15-20 daysearlier but

Buffetin 101/102 August/December 2003 Cad•z conference 19

most arrivedin SAO 2 weekslater than previousyears, and tic coastfrom W Europeto W Africa - in the samewinter- early birds had significantlylower abdominalprofiles. This ing areasas the populationsin decline. Therefore it seems indicatesthat they had stoppedin intermediatewetlands. In unlikely that whateveris driving populationchange is occur- 2003 both early and late patternswere observed.Red Knots ring in either the breedingor wintering areas.Moreover, it arriving early at SAO also arrived significantly earlier in is alsounlikely that the effectsof global climate changeare DelawareBay. Theseresults suggest flexibility in migration currentlysubstantially affecting these populations. strategiesof Red Knots ("time selectedvs energyminimiz- In Stroud et al. (2003) we speculatethat the different ing"). trendsmay be linked to use of different spring/autumnstag- ing areas,and notedthat the Wadden Sea, the major staging areaof the EastAtlantic flyway, is usedextensively for stag- Towards an ecological underpinning of changes ing by populationsin decline.This paperexamines whether in abundance of Red Knots in the Dutch Wadden thereis a link betweenthe populationstatus of the guild of Sea and elsewhere along the East Atlantic Flyway East Atlantic migratorywader populations and the extentof TheunisPiersma •.2, Ben Koks3 & BernardSpaans • their dependencyon the Wadden Sea as their autumn and springstaging area. 1. Royal Netherlands Institutefor Sea Research Spring/autumnstaging dependency on the WaddenSea of (NIOZ), Texel, The Netherlands;2. Centre for Ecologi- the 28 EastAtlantic waderpopulations using coastal habitats cal and EvolutionaryStudies, Universityof Groningen, for wintering and/or stagingwere analysedin relation to The Netherlands;3. SOVON-Bird MonitoringNether- populationtrends. Sourceswere Stroud et al. (2003) for lands, Beek-Ubbergen, The Netherlands; trendsand Meltofte et al. (1994) for the % of eachpopula- e-maih theunis @ nioz. nl tion using the Wadden Sea and the draft Wader Flyway Atlas. The dependencyof each populationon the Wadden From the early 1970s, about 100,000 Red Knots Calidris Sea was coded as 0, <33%, 34-66%, 67-99% or 100%. canutus islandica wintered in the Dutch Wadden Sea. Over Sevenpopulations were excludedfrom the analysisbecause the last few winters, however, that number has declined to they have an uncertainpopulation trend and/or the extent of 20,000 or fewer. Numbersof the othersubspecies using our their Wadden Sea usageis uncertain.Of the 21 populations flyway, Calidris canutus canutus, which winters in West analysed,seven breed in the high arcticand 14 are sub-arctic Africa, approximatelyhalved between 1980 and 1997, but and/or temperatebreeders. For each population,the season sincethen that populationhas apparentlystabilized. From (springor autumn)of highestdependency was selectedfor our detailedecological work in the Dutch Wadden Sea, we analysis. know that the relationship between the numbers of Red For sub-arcticand temperatebreeders there was no rela- Knotsand their food resourcesis particularlyfight, and that tionshipbetween Wadden Sea dependencyand population the mollusc food of Red Knots has been in decline as a con- trend. Most of thesepopulations had low Wadden Sea de- sequenceof ongoingindustrial (mechanized) cockle and pendency,and a wide rangeof populationtrends. Only the musseldredging. An intensecolour marking scheme for both EurasianOystercatcher had a high dependency(and an in- islandica and canutus knots has not been in place long creasingtrend). However, for the sevenhigh arctic-breeding, enoughto establishchanges in survival and recruitmentas long-distancemigrant populations there was a very strong a consequenceof food resources.However, we believe that link between declining trend and high dependencyon the suchwork needsto havepriority if we aim to understandthe WaddenSea (r 2 = 0.83). For eachof the four stableor in- reasonsfor the steepdeclines in wader numbersoccurring creasingpopulations, less than a third of eachdepends on the now in severalparts of the world. Wadden Sea. In contrast,the three populationswith high Wadden Sea dependencyare in seriousdecline. Why is the main problem occurring with high arctic Declines in East Atlantic wader populations: populations?These populations make long distancenon-stop Is the Wadden Sea the problem? flights and needabundant food resourcesfor rapid major re- Nick Davidson fuelling, especiallyin spring.They are alsoknown to face migratory bottlenecksand to have low diseaseresistance Chemin des Jordils, 1261 Le Vaud, Switzerland; (Piersma2003 WSG Bulletin 100). Thereforethey are likely e-mail: linda @irpolink. ch to be most vulnerableto any changein their key stagingarea thataffects their ability to feedand refuel at thenecessary rate, Stroudet al. (2003) identifiedthat someEast Ariantic flyway andto departwith the necessaryreserves to bothmigrate and waderpopulations which breed in the high arcticare in major survivesevere weather in the arctic(Wilson et al. in prep.). decline, notably Bar-tailed Godwit Limosa lapponica,and The Wadden Sea has had little recent intertidal habitat loss two Red Knot populationsCalidris canutus and C. islandica. (land-claim),so has it changedin sucha way that although Thesebreed in differentarctic and subarctic regions (Nearcftc, the tidal flatsare still availabletheir quality has deteriorated? Fennoscandia,Siberia) and winter on different parts of the A major recentand well-documentedchange has occurred in Atlantic coastfrom W Europeto W Africa. However, other the Dutch part of Wadden Sea arisingfrom the intensifica- EastAtlantic flyway coastalmigrant populations are increas- tion of shellfisheries. This is known to have decreased feed- ing: Grey Plover Pluvialis squatarola,Turnstone Arenaria ing opportunitiesfor Red Knots (see e.g. the abstract of interpres, SandpiperC. ferruginea, EurasianOyster- Piersmaet al.). It is not clear whetherthere are othercontrib- catcherHaematopus ostralegus and Ringed Plover Charad- uting factorsaffecting the Wadden Sea,but it may be that the rius hiaticula.Similarly, these increasing populations breed recordedpopulation declines are a reflection of a reduced in different arctic and subarcticregions (Iceland, N Europe overall capacityof the Wadden Sea to supportwader popu- and Siberia), and also winter on different parts of the Atlan- lationsat the critical times in springand autumn.

Bulletin 101/102 August/December 2003 20 WaderStudy Group Bulletin

Participantsin the 2003 InternationalWader Study Group conference at Cadiz, Spain.

It is knownthat there are major pressures on keywader flyways to test could include: Black Sea/Mediterranean stagingareas on other flyways, such as deteriorating food flyway - Sivash (Ukraine); W Asian/E African flyway - suppliesin DelawareBay, USA, andin SE Asiawhere there ArabianGulf: E Asian/Australasianflyway - Yellow Sea:W has been extensive land-claim of intertidal flats. Is there a Atlantic flyway - Bay of Fundy, DelawareBay. On the Pa- similarlink between declining population trends and key cific coastof N America,there are many differentstaging stagingarea dependency for arcticbreeding waders on other sites, and the implicationsof habitat deteriorationare less flyways?This should be tested against the following predic- clear. tions:if keystaging areas are deteriorating ordisappearing, If the lossand deteriorationof key stopoverhabitat con- thenpopulations with high key staging site dependency will tinuesand if its link with populationdeclines is detectedon have a decliningpopulation trend. Also, there will be a differentflyways, then the future for higharctic waders looks strongerlink for higharctic breeding populations than for bleak, regardlessof any addedimpacts of global climate sub-arctic/temperatebreeders. Key stagingareas on other change.

Bulletin 101/102 August/December2003