populations are declining - how will we elucidate the reasons? CHRISTOPHZOCKLER '1, SIMON DELANY2 & WARD HAGEMEIJER2

1UNEP-WCMC,219 HuntingdonRoad, Cambridge, U.K., e-mail: Christoph. Zockler@unep-wcmc. org; 2WetlandsInternational, PO Box471, 6700 AL Wageningen,The Netherlands

Z6ckler, C., Delany, S. & Hagemeijer,W. 2003. Wader populationsare declining - how will we elucidatethe reasons?Wader Study Group Bull. 100: 202-211.

Worldwide,many waderpopulations have beenshown to be in decline,though for someinformation is still lacking.Not all populationsare declining, but long-distance migrants (a majority)appear to be at particular risk. Also at risk are sedentaryspecies with smallpopulations, which comprise a majorityof the extinctand globallythreatened species. The latter are betterstudied, and threats to their futureare relativelywell under- stood.Large-scale population changes in Arcticand north-temperate regions are generally better documented thanin the tropicsor the SouthernHemisphere. The reasonsfor declinesin largeand widespread populations are not well understoodand explanations are mostlybased on sparseand uncoordinated data. The InternationalWaterbird Census (IWC), coordinatedby WetlandsInternational, provides a framework for monitoringnon-breeding populations at a globalscale. However, wader counts are not yet availablefrom mostcountries for enoughyears to allow meaningfulpopulation trend analyses. Nevertheless there is con- siderablepotential for trendanalyses using IWC data in the future.Many otherstudies use different and un- coordinatedmethods. We still lack facilities for broad-scaleanalyses which would allow the reasonsfor observedchanges in waderpopulations to be explored.A GIS referenced,decentralised, web-based database interfaceis proposedwhich wouldhelp explainthese changes by linkingwader monitoring initiatives, and by providingintegration with otherenvironmental monitoring schemes.

EXISTING KNOWLEDGE OF POPULATION STATUS Global assessmentsproduced every three to five yearsby Wetlands International estimate the numbers and summarise Global approaches the statusof waterbirdpopulations, but alsodemonstrate the gapsin our knowledge(Rose & Scott 1994, Rose & Scott Wetlands Internationalhas been publishingresults of the 1997, Wetlands International2002). Wetlands International IWC and trendsin certainwaterbird populations for many (2002) compiledestimates of numbersand trendsfor 499 years(Atkinson Willes 1976, 1978, 1981, RQgeret al. 1986, populationsof 209 speciesrecognised as "".Table 1 van der Ven 1987, 1988, Monval & Pirot 1989, Scott & Rose summarisesthe numberof speciesin eachwader family, the 1989, Perennou et al. 1990, Perennou, 1991, 1992, Perennou numberof biogeographicpopulations into whichthese fami- & Mundkur 1991, 1992, Rose 1992, Mundkur & Taylor lies have beendivided, the numberof populationestimates 1993, Taylor & Rose 1994, Rose 1995, Dodman& Taylor andtrends presented for eachfamily, andthe number of these 1995, 1996, Lopez & Mundkur 1997, Dodmanet al. 1997, trendswhich were estimatedto be increasing,stable, or de- 1998, Delany et al. 1999, Blanco& Carbonell2001, Gilissen creasing.Seven populations which have becomeextinct et al. 2002). This work hasprovided important baseline in- since 1750 are also included. formationabout waterbird numbers, and successfulpopula- Populationestimates are now availablefor a majority tion trend analysishas been possiblefor certain groups, (424, 85%) of waderpopulations (Table 1). The numberof notablyAnatidae in Europe.The censusresults (and hence populationsfor which the trend is now known is abouthalf the IWC data)are incomplete for certainsites, species or re- of this(207, 41%). Of thepopulations with knowntrends, 92 gions.Because of thesegaps, methodological inconsistencies (44%) showa decreasingtrend, 81 (39%) appearto be stable and otherconstraints, trend data are still lackingfor many and only 27 (13%) show an increasingtrend. The baseline populations.Significant efforts are being made at presentto of availablepopulation estimates continues to grow,and we improvethis situation.Waders have only beenincluded in alsoexpect the quantity and quality of populationtrend data IWC in mostcountries for the mostrecent 10 or so yearsof to showimprovements in thecoming years. These improve- its 35-year history, and no wader data are included in the mentswill includean increase in thenumber of waderspecies IWC databasefor years before 1989. Information about for which sufficientdata are availablefor trendanalysis to populationtrends in wadersis thusonly now becoming avail- be meaningful.An expectedincrease in coverageby IWC, able, althoughprospects for future trendanalyses for wad- andthe developmentof monitoringof ImportantBird Areas ers basedon IWC data are very good. (IBAs) underBirdLife International'sIBA programme,will

* Correspondingauthor • Bufietin100April2003 202 ZOckler et aL: Wader populations are declining 203

Table 1, Summaryof data presentedfor waders in Waterbird PopulationEstimates - third edition (Wetlands International2002).

Family No of No of bio- No of No. of species geographic population population populations estimates trends presented 'presented Details of presented trends

Increasing Stable Decreasing Extinct

RostratulidaePainted 2 4 2 1 0 0 1 Dromadididae Crab plovers 1 1 1 1 0 1 0 HaematopodidaeOystercatchers 12 20 20 9 5 3 0 IbidorhynchidaeIbisbill 1 1 0 0 0 0 0 Recurvirostridae Stilts & Avocets 10 25 23 14 4 9 1 Burhinidae Thick-knees 9 25 14 5 0 0 5 Glareolidae Coursers,Pratincoles 17 46 33 12 0 6 6 Charadriidae Plovers & allies 67 156 134 59 11 19 28 ScolopacidaeSnipes, , 90 221 197 106 7 43 51 & allies

Total 209 499 424 207 27 81 92 7

% of populations 85% 41% 13% 39% 44% 4%

alsobe significantin this respect.The challengewill be to temperate Europe and reduced numbers have also been effectivelycombine and present the resultsof numerousand foundon winteringgrounds in West Africa. However, data diverse studiesat a number of scalesin a meaningful and from the Arctic arecurrently too sparseto concludethat there accessible manner. hasbeen an overalldecline in the populationof this still very abundantspecies (Z6ckler 2002). Europe The Americas A major analysisof wadertrends in the WesternPalearctic, usingIWC data, is planned,and a preliminaryanalysis for Considerableeffort is put into shorebirdconservation in one species,the EurasianOystercatcher Haematopus ostra- North America,and comprehensive conservation plans have leguswas presentedin February2002 (Haanstrain prep). beenprepared for the USA (Brown et al. 2000) and Canada BirdLife International/EuropeanBird CensusCouncil (Donaldsonet al. 2000). Morrison et al. (2001) presented (2000) reportedthat about24 of the 42 wader populations populationestimates and trends for North Americabased on breedingin Europeshowed a decreasingtrend whereas only a wide variety of sources,and listed 28 (80%) of the 35 nine showedan increase.A further nine speciesshowed an wader speciesin North America as declining.Of these,19 uncleartrend but severalof thesewere alsothought to be in species(54%) showedstatistically significant or persistent decline.More recentdata also suggesta decliningtrend for negativetrends. For somespecies, such as Red Knot, a pre- Numeniusarquata in Northern Germany (Melter et viously non-significantdeclining trend has sharpenedand al. 1998) andfor RingedPlover Charadriushiaticula around this speciesseems to be in steepdecline in the New World the North Sea (Hfilterlein et al. 2000). as well as the Old World (Baker et al. 2000). Gilissen et al. (2002) reporteda sharpdecrease in the Most American shorebirdsare long-distancemigrants numberof non-breedingRed Knot canutusin The from Arctic and sub-Arctic breeding grounds,which are Netherlandsbetween 2000 and 2002 (source:T. Piersma in monitoredby a number of schemesduring the breeding, litt.). Similarly, Red Knot in the neighbouringvery impor- migration and non-breedingseasons. The Western Hemi- tant stagingarea of the Schleswig-HolsteinWadden Sea sphereShorebird Reserve Network (WHSRN) is the largestof showed a decline between 1988 and 1999 of about 35% these,and includes54 sites(see: http://www.manomet.org/ (GQnther& R6sner 2000). WHSRN/leam.php).American and Canadian biologists have Of 21 wader species monitored over 12 years in the developeda methodfor monitoringArctic waderpopulations WaddenSea, only five have increasedwhereas nine species in the breeding season,and are trying to establish a har- have shownpersistent declines. GQnther & R6sner (2000) monised monitoring programme for all North American recordeddecreases in five Arctic-breedingspecies of which breedingpopulations (Johnston 2001, Skagen,this volume). four were wadersthat had previouslybeen increasing (Grey Efforts are also being made to establish IWC in North Plover Pluvialis squatarola, Red Knot, Dunlin Calidris America, which remainsthe most sizeablegap in the net- alpina and RedshankTringa totanus). They related these work. IWC is well establishedin partsof SouthAmerica, but trendsto possiblechanges in the climate.Data from Zacken- monitoring in the Caribbean and in Central and South berg in the central high Arctic of Greenlandalso showed America remains small in scale, and the proportion of decreasingnumbers of RedKnot during 1995-2002 but stable waterbird populationsfor which estimatesare available is or increasingnumbers of five othershorebird species breed- lower in the Neotropicalregion than in any of the otherfive ing there (Meltofte in press). BreedingRuff Philomachus Ramsarregions (Wetlands International 2002). pugnax populationshave declined substantially all over

Bulletin 100 April 2003 204 Wader Study Group Bulletin

Africa (BirdLife International2000) and many specialisedisland formsare globallythreatened (Table 2). Minton et al. (2001) Zwarts et al. (1998), recordeda decreasebetween countsin recordedthe proportionof juvenilesin trappedsamples of 1980 and 1997 at Bancd'Arguin, the mostimportant site for ,and identified low breedingsuccess for severalspecies, coastalwaders in Africa, in 11 of the 15 speciesmonitored. but an increaseboth in the proportionof juveniles and in Hagemeijer et al. (2000, in press)found lower numbersin overall numbersof one species,Red-necked Stint Calidris 2000 than in 1997 for only one species(Kentish Plover ruficollis, in the wintering groundsin Australia (see also Charadrius alexandrinus). Eleven specieswere found in Minton, this volume). This remains one of the few known higher numbersin 2000 than in 1997, but numbersof nine examplesof anincreasing population in theregion. out of the 15 specieswere still lower thanin 1980. Six spe- Kashiwagi(2002) reportedthat the Dunlin populationin cies showedan increasecompared with 1980. Japanis declining. Zwartset al. (1998) alsocompared their results with those of Salviget al. (1994), who countedthe secondmost impor- Arctic regions tant coastal site in Africa for waders, the mudflats and man- grovesin the BijagosArchipelago, Guinea Bissau. For five Recentinitiatives have included an attemptto monitorbreed- species,they were able to demonstratethat the changesin ing conditionsfor waterbirdsin theArctic on a circumpolar Mauritaniahad been compensated by decreasesor increases basisunder the Arctic BreedingConditions Monitoring pro- in the BijagosArchipelago. However, there was an overall grammecoordinated by MoscowUniversity (Soloviev et al. declining trend in both of thesekey internationalWest 1998).Meltofte (e.g.2001 andhttp://biobasis.dmu.dk) set up African winteringareas for at leastsix waders,five of them a long-termprogramme for monitoringwaders in NE Green- Arctic-breeders. The results of the first simultaneous cen- land relating their numbersand breedingperformance to susesof both of theseimportant areas in 2001 still await otherfeatures of biodiversityand climate. Exo & Solovieva publicationand are expectedto shedmore light on popula- (in prep.) proposeda similarmonitoring scheme for the Lena tion developments. Delta in Arctic NE Russia.E. Pierce & H. Meltofte (in litt.) Underhill et al. (2001) and Venter et al. (2002) noted a haveproposed a pan-Arcticshorebird monitoring network declinein Arctic-breedingTumstone Arenaria interpresand (PASRN), which will analyseexisting time seriesof data Curlew SandpiperCalidrisferruginea populations in South from the breedingas well as stagingand wintering areas in Africa overthe last two decadesof the20th century. Although relation to climatic variables, and discusscommon standards the trend data were only basedon singlesummer surveys for future monitoring. during1999-2001 andcompared with 1981,they confirmed Little has so far been done to link all these datasets and trendsobserved in otherareas along the same flyway (Browne explorepossible reasons for changesin numbersof waders et al. 1996 for British non-estuarinecoastal waders, G•inther and other waterbirds. & R6sner 2000 for the German Wadden Sea area). These trendswill, in the comingyears be clarified, togetherwith REASONS FOR THE DECLINES thoseof manyother populations, by thegrowth in time series of wader data held on the IWC database.In Western Africa, Here we straggleand the wide rangeof reasonsgiven (e.g. in Senegaland aroundLake Chad, numbersof Black-tailed BirdLife International 2000) includes: development of Limosa limosa and Ruffs (OAG M[inster 1991, coastalwetlands for industry,infrastructure, and aquaculture; 1996, Triplet & Y•sou 1998) appearto have declinedcon- habitatloss and modificationdue to global climate change siderably,but againthe datado not yet allow a final conclu- and agriculturalintensification; increasing predation pres- sion.The possibilitycannot be excludedthat both thesenu- sure,pollution, hunting and other forms of directhuman dis- merous speciesmight have redistributedthemselves into turbance.Barter (2002) detailsthe considerableand press- many smallerflocks spreadover a largerarea and hencehave ing threatsto the shorebirdsof the Yellow Sea(for example, beenoverlooked (Triplet & Y•sou 1998, Brouwer& Mulli• over 1,100 km2 of tidal flats are known to have been de- 2001). The forthcomingpublication of African IWC results stroyedin the 20th century,and further destruction on a vast for 1999-2001 (Dodman& Diaganain press)will containall scaleis continuing).In most cases,the conclusionsremain of the aboveinformation for that period,complemented by ratherspeculative due to a lack of baselinemonitoring, in- the resultsfrom all other countriesthat participatedin the consistentdata seriesand little integrationof different stud- AfWC over theseyears and will contributeconsiderably to ies.Around the Yellow Sea,baseline monitoring has begun, the understandingof populationdevelopments. but too late to allow an understandingof what hasbeen lost. In manycases, when no obviousreason is apparent,the first Asia-Pacific thoughtis climatechange. The declineof nearly half of all known populationsthroughout all global regionsdoes sug- For theAsia-Pacific flyways, fewer data are currently avail- gest underlying global phenomena.But among the many able for populationtrend assessments.Important baseline causesof populationdeclines often considered, direct loss of work hasbeen undertaken in Australia(e.g. Watkins1993) habitatis frequentlysuspected (e.g. Morrison et al. 2001, and recently in perhapsthe most importantsingle staging Tomkovichet al. 2002, Johnston2001). Other globallyop- areain theregion, the Yellow Sea(Barter 2002). A compre- erating phenomenasuch as eutrophication,with nutrient hensive review and publication of results of the Asian over-enrichmentin wader habitatschanging breeding con- Waterbird Censusis expectedin late 2003. The population ditionsand food supplies,have alsobeen considered (Bein- size of the globally threatened Spoon-billed Sandpiper temaet al. 1995, Z6ckler 2002). No doubta complexmatrix Eurynorhynchuspygmea continuesto decline steeplyand of many inter-correlatedfactors impacts on wader popu- gives cause for concern (Tomkovich et al. 2002). Nord- lations. Some of these factors are discussed below. mann's GreenshankTringa guttifer is similarly threatened

Bulletin 100 April 2003 ZOckleret aL: Wader populationsare declining 205

Sedentary (N = 50) Short-distance & intracontinental Intercontinental (N = 113) (N =41)

Increasing Increasing 8% Extinct 12% 14% Increasing Extinct 1% 27%

Decreasing Decreasing 47% 51% Decreasing table 44% 35%

Stable 22%

Fig. 1. Trendsin Waderpopulations summarised according to theirmigration behaviour. Sedentary = notknown to migrateat all; Short distanceand Intra-continentalmigrant = migrateswithin, but not acrossthe boundariesof Ramsar regions;Intercontinental migrant = migratesacross boundariesof Ramsar regions.

Predation populationsfor which trendsare known,the proportionin declineis ratherlower at only 34% (Fig. 1). In comparison, The relationshipsbetween Lemming cycles, predation by increasingtrends are found in 14% of sedentaryspecies and ArcticFoxes and mortality of Arcticnesting birds (Summers in 27% of short-distanceand intra-continentalmigrants, but & Underhill 1987) hasbeen widely recognisedand similar in only 8% of intercontinentalmigrants. relationshipshave been recordedin regionsoutside the There seemsto be no clear reason why migrant popu- Arctic.The datafrom Siberiaand the connectedflyways sup- lations shouldbe decliningmore than others.Possibly the port the lemmingtheory (Underhill et al. 1989). However, risksof migrationhave increasedbecause of someglobally eightyears of datafrom high Arctic Greenland(Meltofte actingchange. However, this is mere speculation.Coordi- 2001, in litt.) do not supportsuch a simplecorrelation for this natedand consistent monitoring, combined with powerfuland partof the Arctic.There has been good or moderatebreed- sensitivespatial analysis using all availabledatasets, will ing successirrespective of lemmingnumbers and never a enableus to reacha betterunderstanding of thisapparent cor- poorbreeding year coinciding with low lemmingdensities. relation.Furthermore this underlinesthe need for a flyway The predationpressure on breeding waders in temperatewet approachin theconservation of thesespecies. Fortunately, the grasslandby foxes, weaselsand crowshas been demon- RamsarConvention, with its networkof designatedsites, and strated(e.g. Beintemaet al. 1995,Schoppenhorst 1996)and the Bonn Conventionwith the African-EurasianMigratory links betweenwader population size and rodent abundance WaterbirdAgreement (AEWA), as well as otherregional seemlikely (Schoppenhorstin prep).However, apart from conservationstrategies, are formulated to take accountof the sedentaryisland forms where predation by humansduring specialrequirements of long distancemigrants. and after settlement,and by rats, catsand othercommensal Sedentaryspecies with smallpopulations also appear to predatorsis a particularproblem, there is little evidencethat be at particular risk becauseof the high proportionthat predationhas been the primarycause of long-termpopula- appearin the 30 populationsthat are globallythreatened or tion changesin waders. havebecome extinct since the year 1750 (Table2) 14 of these populationsare (or were) sedentary.13 occur(or occurred) Migratory behaviour in Oceaniaand 10 in Asia. 18 canbe categorisedas special- ised islandforms, 12 as ploversand allies with specialised Populationtrends appear to be associatedwith themigratory habitatrequirements and 5 aslong distance migrants (Eskimo behaviourof waderspecies (Fig. 1). There are alsodiffer- Curlew, Bristle-thighed Curlew, Slender-billed Curlew, encesbetween the waderfamilies. The Haematopodidaeand Nordmann'sGreenshank and Spoon-billedSandpiper). Two Recurvirostridaeinclude a highproportion of non-migratory populations,both susceptible to habitatloss or modification, populations,and their populations are, with notableexcep- do not fit into thesecategories: Jerdon's Courser Rhinoptilus tions,mostly stable or increasing(Table 1). The two largest bitorquatus,and Wood nemoricola.Gen- families,Charadriidae and Scolopacidae include a highpro- erally,globally threatened populations are better studied, and portionof long-distancemigrants and show similar popula- the threats to them better understood than is the case for more tion trends, with 47% (Charadriidae) and 48% (Scolopa- numerousand widespread species. Partly this is a reflection cidae)of their knownpopulations in decline,and only 19% of successfulpriority setting by organisations such as and7% respectivelyof theirpopulations increasing. Six of BirdLife International.The challengesnow areto implement theincreasing plover populations are sedentary tropical lap- effectiveconservation action for globallythreatened species, wingspecies, and if theseare excluded, the proportion of the andto identifythe relative importance of thethreats impact- populationsof ploversthat are increasing is reducedto 8%. ing more numerousand widespreadspecies. Thereare exceptions,such as the Red-neckedStint and the PurpleSandpiper Calidris maritima, but a disproportionate Climate change numberof migratorywader populations appear to be in de- cline. 47% of intercontinentalmigrant populationswith Climatechange is alreadyaffecting wader populations and known trends and 51% of intra-continental and short-dis- is predictedto havea very muchmore substantialimpact, tancemigrants are in decline.However, in thosesedentary mostlynegative, over the next 50-100 years(Rehfisch &

Bulletin 100 April 2003 206 Wader Study Group Bulletin

Table 2. Summaryof globallythreatened and extinctwader populations(Sources: Wetlands International 2002, BirdLifeInternational 2000).

Explanation of the columns: Species/Population - the taxa are listedat the level of biogeographicalpopulations (see Wetlands International2002); Ramsat Regions - the Ramsar Conventionon Wetlands dividesthe world into 6 Regions:Asia, Oceania, Africa, Europe, North America and South America; Migratory Behaviour - Sedentary= not knownto migrateat all, - Intra-continentalmigrant = migrateswithin, but not acrossthe boundaries of Ramsar regions,- Intercontinentalmigrant = Migrates across boundariesof Ramsar regions IUCN Threat Status - EXT = Extinct,CR = CriticallyEndangered, EN = Endangered,VU = Vulnerable,NT = Near-Threatened(See BirdLife International2000). SubantarcticSnipe is includedbecause two sub-species(:biogeographical populations in this case) have become extinct,although the speciesas a whole is not consideredto be globallythreatened by IUCN, whichworks at species level. Population trend - EXT = Extinct,DEC = Decreasing,STA = Stable, INC: Increasing

Species/population Range Migratory behaviour IUCN Threat Population Population (Ramsar region(s)) Status estimate trend

CanarianBlack Oystercatcher Africa Sedentary EXT 0 EXT Haematopus meadewaldoi ChathamIsland Oystercatcher Oceania Sedentary EN 140-150 INC Haematopus chatamensis Black Stilt Oceania Intra-continental migrant CR 40 DEC Himantopusnovaezelandiae Jerdon's Courser Asia Sedentary CR 50-250 DEC Rhinoptilus bitorquatus JavaneseWattled Lapwing Asia Sedentary CR <50 EXT? Vanellus macropterus Sociable Lapwing, Asia, Africa Intercontinentalmigrant VU 400-1,200 DEC Vanellus gregarious winteringNE Africa SociableLapwing, Asia Intra-continentalmigrant VU 200-600 DEC Vanellus gregarious wintering South Asia Dotterel Oceania Intra-continentalmigrant VU 1,450 INC? Charadrius obscurusaquilonius New Zealand Dotterel Oceania Intra-continentalmigrant VU 150 INC Charadrius obscurus obscurus Piping Plover North America Intra-continentalmigrant VU 2,920 INC Charadrius melodus melodus Piping Plover North America Intra-continentalmigrant VU 72 STA Charadrius melodus circumcinctus (Great Lakes) Piping Plover North America Intra-continentalmigrant VU 2,950 DEC Charadrius melodus circumcinctus (Prairies) St Helena Plover Africa Sedentary EN 435 STA Charadrius sanctaehelenae Mountain Plover North America Intra-continentalmigrant VU 8,000-9,000 DEC Charadrius montanus Shore Plover Oceania Sedentary EN 159 STA Thinornis novaeseelandiae

Crick, this volume; Smart & Gill, this volume). Its effect can THE ADVANTAGES OF INTEGRATED SPATIAL vary from direct impactsaffecting breedingperformance ANALYSIS (Boyd & Madsen 1996, Ganter & Boyd 2000, Z6ckler & Lysenko2000) to indirect impactscaused by changesin The total effort that goesinto waterbirdmonitoring all over habitat conditions(Z6ckler 2002) or availability. Further the world is huge. There are well organisedinternational indirecteffects might occurvia the food chain if predators initiatives like the International Waterbird Census and Im- areforced to switchfrom eatingrodents to waderchicks after portant Areas programmes,but there are also many climatechange has alteredthe vole or lemming cycles.Evi- more small-scalemonitoring schemes that are inconsistent denceof the impactof globalwarming on the vole cyclehas with thesemajor activities. Most monitoringis dependenton been demonstrated for the Lake Constance area in South local or nationallevel facilities,logistical support and fund- Germany(Schuster et al. 2002). ing. It is incompletein bothspecies and spatial coverage and

Bulletin 100 April 2003 ZOckler et al.: Wader populations are declining 207

Table 2 cont, Summary of globally threatened and extinct wader populations (Sources: Wetlands International 2002, BirdLife Interna- tional 2000).

Explanationof the columns: Species/Population - the taxa are listedat the level of biogeographicalpopulations (see Wetlands International2002); Ramsat Regions - the Ramsar Conventionon Wetlands dividesthe world into 6 Regions:Asia, Oceania, Africa, Europe, North America and South America; Migratory Behaviour - Sedentary = not knownto migrate at all, - Intra-continentalmigrant -- migrateswithin, but not across the boundaries of Ramsar regions, - Intercontinentalmigrant = Migrates across boundariesof Ramsar regions IUCN Threat Status - EXT = Extinct,CR = CriticallyEndangered, EN = Endangered,VU = Vulnerable, NT -- Near-Threatened (See BirdLife International 2000). Snipe is included because two sub-species (=biogeographical populations in this case) have become extinct, although the species as a whole is not considered to be globally threatened by IUCN, which works at species level. Population trend - EXT = Extinct, DEC = Decreasing,STA = Stable, INC = Increasing

Species/population Range Migratory behaviour IUCN Threat Population Population (Ramsar region(s)) Status estimate trend

Wrybill Oceania Intra-continentalmigrant VU 4,100-4,200 DEC Anarhynchusfrontalis Amami Asia Sedentary VU 2,500-10,000 DEC Scolopax mira Moluccan Woodcock Asia Sedentary VU 2,500-10,000 DEC Scolopax rochussenii ChathamIsland Snipe Oceania Sedentary VU 2,000 STA Coenocoryphapusilla SubantarcticSnipe Oceania Sedentary NT 0 EXT Coenocoryphaaucklandica barrierensis SubantarcticSnipe Oceania Sedentary NT 0 EXT Coenocoryphaaucklandica iredalei Wood Snipe Asia Intra-continental migrant VU 2,500-10,000 DEC Gallinago nemoricola Eskimo Curlew North America, Intercontinental migrant CR <50 EXT? Numenius borealis South America Bristle-thighedCurlew North America, Oceania Intercontinentalmigrant VU 10,000 DEC Numenius tahitiensis Slender-billed Curlew Asia, Europe, Africa Intercontinentalmigrant CR <50 DEC Numenius tenuirostris Nordmann' s Greenshank Asia Intra-continentalmigrant EN 250-1,000 DEC guttifer Tuamotu Sandpiper Oceania Sedentary EN 250-1,000 DEC Prosobonia cancellata Ellis' s Sandpiper Oceania Sedentary EXT 0 EXT Prosobonia ellisi White-winged Sandpiper Oceania Sedentary EXT 0 EXT Prosobonia leucoptera Spoon-billedSandpiper Asia Intra-continental migrant VU <3,000 DEC Eurynorhynchuspygmaeus

in time series.Moreover, there is a lack of goodintegration The incomplete,scattered and unevenly distributed status and linkagewith otherbiological or scientificinitiatives. of trend data acrossthe Arctic and northerntemperate re- Waterbird monitoringhas stronglyadvanced in recent gionsand betweentaxa hasbeen recognised by the Council years,and IWC is providingan ever more effectiveframe- on Arctic Flora andFauna (CAFF) biodiversitymonitoring work. BirdLife Internationalis alsodeveloping monitoring working group.At present,this consistsof eight active spe- basedon its network of IBAs. Many of theseare wetlands ciesnetworks working on PolarBears, seabirds and seals, as and in those cases IWC data have often been used to iden- well asArctic Char, Reindeer, geese, vegetation and waders. tify them.However, the opportunitiesfor spatialand inter- They all aim to operateat a circumpolarscale and to har- taxonomicintegration as well as the integrationof observer monisepopulation trend data for integrationpurposes. networkshave not yet been fully explored.This has been The Arctic region has the great advantageof relatively recognisedby WetlandsInternational, BirdLife International few direct negative impactsfrom human activity. Mineral and the UNEP-World ConservationMonitoring Centre and exploitationand resulting acid rain, togetherwith over- flyway scaleprojects have been designed to link datagath- grazing by livestock in someregions, have considerable ering, databasesand the spatialreference. impact,but the sheergeographical scale of the region and

Bulletin 100 April 2003 208 Wader Study Group Bulletin verylow humanpopulation densities mean that there are still ing of physicalparameters and pollution are well established vast areasof pristinewilderness. Because direct human im- (e.g.the GlobalTerrestrial Observation System GTOS) and pactin theArctic remains at a very low level,most develop- are coveredfor the Arcticregion by the Arctic Monitoring mentsthat havebeen observed there can be interpretedas andAssessment Programme (AMAP) of the Arctic Council. naturaleffects or globalphenomena, such as climate change Theprototype is aimedtowards the design of a geo-referenced andeutrophication. Current problems with existingmonitor- webportal starting with a selectedset of databaseapplications ing programmesinclude the lack of informationon many that will allow preliminaryintegration and analysesof relevanttaxa, a biastowards harvested, and/or rare species, geographicallyharmonised data. Further development will inconsistencyof coverage,gaps in dataseries and, perhaps graduallyimprove access to more and more databases.A mostimportantly, a lack of integratedanalyses. preliminarydemonstration web sitewith onlylocal database As knowledgeof the flyways usedby different popu- accesshas been established and can be downloadedat http:// lationsincreases, it becomespossible to relatepopulations trinity.unep-wcmc.org/imaps/arcticBirds/viewer.htm. monitoredin the non-breedingseason to definedareas of the Many importantcomponents of biodiversityare not moni- Arctic.The comparisonof two distinctAustralian wintering toredat all, or monitoringdata are only available for selected populationsof Red Knot monitoredin SE andNW Australia, regions. Few efforts have been made to achieve a circum- for example,give evidence about the differentbreeding per- polarmonitoring of Arcticbiodiversity. Most noteworthy is formanceof eachpopulation, although the precisebreeding the ArcticBreeding Conditions Monitoring programme run distributionof eachof thesepopulations is stillpoorly known by MoscowUniversity (Soloviev et al. 1998)and supported (Minton et al. 2001). by theDutch Government. Similar programmes are in devel- Rare speciesnaturally receive more attention and are opmentfor Reindeer,Arctic Char, and seabirdsand to some morelikely to be monitoredthan common species (Table 2.). extentfor geeseand somewaders, but rarely on a circum- Therefore somechanges may be recordedmore readily polarbasis, involving more than just one country.A large amongrare species.However, those factors affecting changes numberof waderpopulations breed in the Arctic regionand in numbersthat are of a more global, overridingcharacter theWader Study Group is ideallypositioned and well expe- can only be detectedby monitoringcommoner species. The riencedto contributesubstantially with their datato inte- declinein the non-breedingpopulation of Dunlin in Japan gratedmonitoring of Arctic Biodiversity. might be causedby the sameproblems that affect Spoon- The conceptproposed here is basedon an interactiveinter- billedSandpipers. However, the reasons for thesharp decline facethat could provide access to separatelymaintained and of the Spoon-billedSandpiper have not yet beenidentified updatedspecies databases with trend data and information (Tomkovich et al. 2002). More data on the larger wader suchas lemmingdensity and weather parameters hosted at populations,as well as othertaxa and environmentalpara- differentlocations. Fig. 2 showsa proposedprototype for the metersin the Asia-Pacificregion are required before we can Arcticregion with a few selectedlayers on biodiversity taxa, properlyevaluate the varioushypotheses. includingdata on protectedareas and the potential for exten- In orderto facilitatean understandingof the reasonsfor sionto includemany other species and parameters. declinesin waderpopulations we proposeto designa web- The potentialoutput is enormousbut will verymuch de- basedGIS interface(also known as a "portal",see Fig. 2), pendon the initial input andthe maintenanceof decentral- to integrateefforts to monitorbiodiversity throughout the isedor distributeddatabases. Each participating organisation Arctic. We plan thatthis will comprisea collationof decen- or datacustodian would maintain their own specialistdata in tralisedand distributedweb databasescontaining monitor- theirown database,with the advantagesof familiarityand ingdata and other relevant spatial datasets. The same can be regularupdating of information.The mostobvious challenge donewithin each of themajor flyway systems and a proposal lies in the analysisof biodiversitytrend data, both in itself hasbeen prepared to implementthis (not only for wadersbut andin relationto factorssuch as climate change. The Arctic for all waterbirds)for the AEWA region. regionand its biota seemcertain to experiencepronounced The designof the new interfacewill allow thesedata to changesin climatein thecoming years (IPCC 2001, Rehfisch be accessedand displayed geographicallythrough the & Crick,this volume) and the proposed portal could provide Intemetand overlaid with physicaldata relating to variables theintegration of essentialdata sets and allow analysis of the suchas climate, nutrient levels and pollution. The webpor- relativeimportance of differentparameters. tal will link and make accessiblegeo-referenced databases One outputmight be thedevelopment of "ArcticSpecies of monitoringdata from many differentArctic or flyway TrendIndices" in line with theLiving Planet Index currently biota.It will serveas a platformfor connectingand access- undertakenby WWF andUNEP-WCMC (Loh 2002), or the ing all availabledata for the Arctic or flyway region.It will NaturalCapital Index (ten Brink 2000). Dependingon the alsoallow access to dataon parameters such as habitat type, varietyof taxa includedin the monitoringprogramme, re- protectedarea status and others. The portal,here a selected gionalsubsets of theindices could be developed.A marineor prototypefor the Arctic region,will help to combinetrend terrestrial index would illustrate differences in trends between data of waderpopulations with thoseof othertaxa, if avail- thesebiomes and regional subsets could highlight differences able,using advanced GIS applications.It is designedto handle betweenregional seas or betweenselected terrestrial regions. dataat differentscales and of differenttypes, harmonised in Furthermore,the interface could be setup to allowhabitat or a collationof databases,which will allow integration,com- ecosystemrelated indices. Another possible distinction in the parisonsand finally trendanalyses. In addition,the datacan interfacecould refer to migratoryspecies, including whales, be integratedwith thoseof land use and land management, seabirds,geese and waders.Comparing trends of migratory climate, acidification,water level changes,industrial and taxawith thosesedentary in theArctic (including, e.g., mam- agriculturalpollution and otherssuch as reindeerdensity, mals,freshwater fishes and plants) would provide further in- miningsites and infrastructure. Many of therequired data are dicationson the geographicalorigins of observedtrends. not fully availableor are in development,but the monitor- Trend dataon wadersare still scarce,but thosewell established

Bulletin 100 April 2003 ZOckler et aL: Wader populationsare declining 209

Arctic BiodiversityArias I[]1[] Goto Legen___•

Layers

Thick-billed M•rre

• BreedingCommon

Bree•ing Sites

• =Coloni•Goo• Breeding • InternationalProte•ed

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IntemMio•al Prote•ed • Areas(po•ons) Co•,.igh*L,IC)U•tEP.-WCUC• • • •e•N•onal (pol•o•)P•ote•e• • S•ipa Bree•ing RefreshM•

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Fig. 2. Suggestedprototype of an interactiveinterface for the Arcticregion, serving as a platformto access,manage and integrate monitoringdata (and otherrelevant spatial datasets) using modern web-based GIS applications. asin EastGreenland (Meltofte 2001) or on a circumpolarscale facilities. If funding for this approachcan be obtained, it (Solovievet al. 1998, Soloviev& Tomkovich2001) couldbe shouldalso allow betternetworking between and within re- readilyintegrated, others encouraged to join andeven those searchgroups and better coordination of monitoringas well networkssuch as the IWC operatingoutside the Arctic could as betteruse of modernGIS applications. be linked to the Arctic region,when we know the breeding distributionsof the monitoredpopulations. ACKNOWLEDGEMENTS Anothervaluable opportunity would be to correlatewader trend data with natural fluctuations, such as small rodent Without the many thousandsof mostlyvoluntary waterbird cycles,and also with anthropogenicimpacts such as pollu- counterswho participatein IWC and otherwaterbird moni- tion (AMAP data),climate change and others. With improve- toringprogrammes all over the world, it would be impossi- mentsin thequality and quantity of availabledata from vari- ble to describeany trendor discussthe reasonsbehind them ous sourceswe shouldbecome more confidentin our ability at all. Ian May helpedwith settingup a preliminaryInternet to distinguishclimate-related changes or otheranthropogenic web serverfor demonstrationpurposes. We would like to factors from natural fluctuations. expressour thanksto all of them. We also wish to thank Ideally,the structureof the interfaceshould be designed HumphreySitters and Hans Meltofte for their constructive in sucha way that it canbe transferredand made applicable and encouragingcomments on an earlier draft. for otherregions and biomes. The advantagesof startingwith an Arctic prototype are: REFERENCES

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