waterbird colony count at lake urema, parque nacional da
TRANSCRIPT
WaterbirdcolonycountatLakeUrema,ParqueNacionaldaGorongosa
Mozambique,MarchandApril2019
JasonDenlinger,Dr.MarcStalmans,Dr.TaraMassad,
April2019
1
PhotosTaraMassad
Tableofcontents
Pagenumber
Summary 3
1.Surveymethodology 7
2.Results 8
2.1Nestnumbersrecorded 8
2.2Species-by-speciesresults 11
2.3AddiOonalspeciesobservaOons 18
3.Discussion 19
4.References 21
5.Acknowledgements 22
2
Summary
• AdetailedcountofthewaterbirdcolonyattheedgeofLakeUremawasconductedon12Marchandon16April2019.Thecountwasconductedinthesameareaandaccordingtothesameproceduresasapreviouscounton7April2014.
• Todate,onlythreesystemaOccountsofthiswaterbirdcolonyhavebeendocumented.
• Thecolonywaslocatedatthesouth-eastcornerofLakeUrema(Fig.1)andextendedacrossadistanceof1.6kmfrom18.89996S;34.49986Eto18.91015S;34.51075E(coveringapproximately15ha).
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Fig.1.MapofGorongosaNa<onalPark,Moçambique,showingtheloca<onofLakeUremaandthewaterbirdbreedingcolony
(Stalmansetal.2014).
Summary-con<nued
• On14March,CycloneIdai,acategory2cyclone,madelandfallalongthecoastofBeira,MoçambiquefellingtreesandcausingwidespreadfloodingwithinGorongosaNaOonalPark(GNP).SatelliteimagesshowtheincreaseinsurfaceareaofLakeUremaandoverflowofconnectedrivers.
• Thisreportcomparestheresultsofthepre-andpost-cyclonecountsconductedin2019,MarchandAprilrespecOvely.ItalsocomparestherecentcountwiththeearliercountofApril2014.
4
Fig.2.Satellitedetectedwatersextents,asof19and20March2019overSofalaprovince,GNPandLakeUrema
(sources:AtmosphericandEnvironmentalResearch&AfricanRiskCapacity&UNOSAT).
Summary-con<nued
• On12March2019atotalof2,432nestsof7differentspecieswerecounted.
• On16April2019,atotalof3,791nestsof7differentspecieswerecounted.
• Thisrepresentsanincreasein1,359nestsfromtheearlierMarchcountdespitetheimpactsofCyloneIdai’slandfallintheregion.
Species Mar-19 Apr-19
African Darter Anhinga rufa 722 671
Reed Cormorant Phalacrocorax africanus 191 741
White-breasted Cormorant P. lucidus 189 308
Great Egret Egretta alba 112 99
Black-headed Heron Ardea melanocephala 9 0
Grey Heron A. cinerea 0 42
African Sacred Ibis Threskiornis aethiopicus 0 0
African Openbill Anastomus lamelligerus 581 1034
Yellow-billed Stork Mycteria ibis 628 896
Total nests (all species) 2432 3791
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Table1:side-by-sidecomparisonofthenumbersofwaterbirdnestsinthesamecolonybetween
MarchandAprilof2019.
Summary-con<nued• However,therewere1,212fewerbirds
countedinApril2019comparedtoApril2014withthelowernumbersmostlytheresultoffewerReedCormorantsbeingpresent.
• InApril2014therewere5,003nestscountedin463treescomparedtothe3,791nestsfoundin382treesduringtheApril2019count.
• Themostnumerousspeciesobservedin2019weretheAfricanopenbill,whilein2014therewerefarmoreReedcormorantthananyotherspecies.
• ThewaterbirdcolonyonLakeUremaconOnuestorepresentoneofthemostimportantconservaOonvaluesofGorongosaNaOonalPark.Theearly-seasonfloodingaswellasthesubsequentaddiOonalfloodingcausedbythecyclonehavecreatedexcellentcondiOonsforasuccessfulbreedingseason.
Species Apr-14 Apr-19
African Darter Anhinga rufa 547 671
Reed Cormorant Phalacrocorax africanus 2276 741
White-breasted Cormorant P. lucidus 230 308
Great Egret Egretta alba 330 99
Black-headed Heron Ardea melanocephala 0 0
Grey Heron Ardea cinerea 82 42
African Sacred Ibis Threskiornis aethiopicus 24 0
African Openbill Anastomus lamelligerus 531 1034
Yellow-billed Stork Mycteria ibis 983 896
Total nests (all species) 5003 3791
6
Table1:side-by-sidecomparisonofthenumbersofwaterbirdnestsinthesamecolonybetween
April2014andApril2019.
1. Surveymethodology
AllnestswereindividuallycountedpernesOngtreeandperspeciestotheextentpossible.Insomecasestreesweregroupedtogetherwhendifficulttodiscernthedifferencesbetweennestsonbrancheswithincloseproximitytoeachother.Nestswerecountedfromaboatwithinca20–100mofthecolony.Ateamof5observerswereusedinboththeMarchandAprilcounts.
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Fig.3.BoatusedtovisitwaterbirdbreedingcolonywithfloodedFaidherbiatreesinthebackground(photoJasonDenlinger)
Fig.4.RepresentaOveviewoftheLakeUremawaterbirdbreedingcolony.SpeciespicturedincludeOpenbillstork,Yellow-billedstork,andGreategret(photoJasonDenlinger)
2.Results2.1Numbersofnestsrecorded
Table3.ResultsofcountofcolonialwaterbirdsbreedingatLakeUrema,GorongosaNa<onalPark,on12March,2019.
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Species No. of nests No. of trees with
nests Average nests/tree Max. nests per tree African Darter Anhinga rufa 722 126 5.7 44 Reed Cormorant Phalacrocorax africanus 191 21 9.1 45 White-breasted Cormorant P. lucidus 189 49 3.9 21 Great Egret Egretta alba 112 45 2.5 10 Black-headed Heron Ardea melanocephala 9 6 1.5 3 Grey Heron A. cinerea 0 0 0 0 African Sacred Ibis Threskiornis aethiopicus 0 0 0 0 African Openbill Anastomus lamelligerus 581 138 4.2 31 Yellow-billed Stork Mycteria ibis 628 147 4.3 29
Total (all species) 2432 340 7.2 45
Table4.ResultsofcountofcolonialwaterbirdsbreedingatLakeUrema,GorongosaNa<onalPark,on16April,2019.
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Species No. of nests No. of trees with
nests Average nests/tree Max. nests per tree African Darter Anhinga rufa 671 108 6.2 25 Reed Cormorant Phalacrocorax africanus 741 76 9.8 41 White-breasted Cormorant P. lucidus 308 56 4.3 19 Great Egret Egretta alba 99 37 2.7 6 Black-headed Heron Ardea melanocephala 0 0 0 0 Grey Heron A. cinerea 42 37 1.1 4 African Sacred Ibis Threskiornis aethiopicus 0 0 0 0 African Openbill Anastomus lamelligerus 1034 147 7 27 Yellow-billed Stork Mycteria ibis 896 187 4.8 29
Total (all species) 3791 382 9.9 70
Table5.ResultsofcountofcolonialwaterbirdsbreedingatLakeUrema,GorongosaNa<onalPark,on7April2014.
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Species No. of nests No. of trees with
nests Average nests/tree Max. nests per tree African Darter Anhinga rufa 547 118 4.6 25 Reed Cormorant Phalacrocorax africanus 2276 219 10.4 53
White-breasted Cormorant P. lucidus 230 54 4.3 22
Great Egret Egretta alba 330 131 2.5 12
Black-headed Heron Ardea melanocephala 0 0 0 0
Grey Heron A. cinerea 82 66 1.2 3
African Sacred Ibis Threskiornis aethiopicus 24 4 6 12
African Openbill Anastomus lamelligerus 531 112 4.7 13
Yellow-billed Stork Mycteria ibis 983 259 3.8 23
Total (all species) 5003 463 10.8 58
11
0
100
200
300
400
500
600
700
800
2014 2019
AfricanDarterNestsinApril
0
100
200
300
400
500
600
700
800
March April
AfricanDarterNests20192.2Species-by-speciesresultsAfricandarternestswerethemostnumerousinMarch,butbyApril2019hadbeenoutnumberedbyseveralotherspecies.
However,thedarternestsdecreasedonlyslightlybetweenMarchandAprilwhileothersincreasedmoresignificantly.ThepresenceofnumerousnearlyfledgingdarterchicksindicatethatthesenestsweremostlynotnegaOvelyaffectedbythecyclone
Therewere124moredarternestsin2019thanin2014represenOnga23%increase.
Fig.5.Africandarter(photoTaraMassad)
12
0
100
200
300
400
500
600
700
800
March April
ReedCormorantNests2019TherewerealmostfourOmesasmanyReedcormorantnestspresentinAprilthanMarchof2019.
Despitethis,therewere1,535fewerReedcormorantnestsinApril2019whencomparedtoApril2014.
Thisspeciesalonemakesupfortheoveralldecreaseinnestsbetween2014and2019;with5003and3791nestsrespecOvely.
Fig.6.Reedcormorant(photoTaraMassad)
0
400
800
1200
1600
2000
2400
2014 2019
ReedCormorantNestsinApril
ThenumberofWhite-breastedcormorantnestsdidnotfluctuategreatlybetweenMarchandApril
of2019norwhencomparingyears2014and2019.
However,therewasanincreaseby63%from
MarchtoAprilof2019.
Therewere34%moreWhite-breastedcormorants
inApril2019thanApril2014.
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0
50
100
150
200
250
300
350
March April
White-breastedCormorantNestsin2019
0
50
100
150
200
250
300
350
2014 2019
White-breastedCormorantNestsinApril
Fig.7.White-breastedcormorants(photoTaraMassad)
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Only13moreGreategretnestswereobservedinMarchthanAprilof2019.
ThenumberofGreategretnestscountedin2014werealmostthreeOmesasmanyasin2019.
Fig.8.Greategrets(photoTaraMassad)
0
50
100
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250
300
350
2014 2019
GreatEgretNestsinApril
0
20
40
60
80
100
120
March April
GreatEgretNestsin2019
Duringthe2014surveytherewerenoBlack-headedheronnestsobserved.InMarchof2019
therewereninenestsofthisspeciesobserved.
However,uponreturningagaininApril2019there
werenolongeranynestsofthisheronspecies.
ItcouldbethattheBlack-headedheron’swere
displacedbyGreyheronswhichwerenotpresent
duringtheMarch2019count.LaterinApril
2019,42Greyheronnestswerecounted.
However,therewerenearlyhalfasmanyGrey
heronnestsobservedin2019aswerecountedin
2014.
Furthermore,noAfricansacredibiswereobserved
duringeithercountin2019,whereas24were
observedin2014.
15
0
10
20
30
40
50
60
70
80
90
2014 2019
GreyHeronNestsinApril
Fig.9.Greyheron(photoTaraMassad)
16
0
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400
600
800
1000
1200
2014 2019
AfricanOpenbillNestsinApril
0
200
400
600
800
1000
1200
March April
AfrianOpenbillNests2019ThenumberofAfricanopenbillnestscountedinApril2019nearlydoubledcomparedtothosecountedinMarchof2019.
Openbillsshowedthegreatestincreaseofallspeciesin2019comparedto2014withalmosttwiceasmanynestsobservedinApril2019.
Fig.10.Africanopenbills(photoTaraMassad)
17
0100200300400500600700800900
1000
2014 2019
Yellow-billedStorkNestsinApril
01002003004005006007008009001000
March April
Yellow-billedStorkNestsin2019ThenumberofYelllow-billedstorknestsincreasedapproximately43%fromMarchtoApril2019.
Yellow-billedstorknestsdecreasedbylessthan10%from2014to2019.
Thisspecieshasbeenthe2ndmostpopulousinthecolonyduringeachcount.
Fig.11.Yellow-billedstorks(PhotoTaraMassad)
2.2.Addi<onalspeciesobserva<ons19Southern-maskedweavernestswereobserved
hangingfromthetreesinMarch,butabsentin
Aprilof2019.
SeveralPink-backedpelicanswereobservednear
thecolony,butnotwithnests(Fig.12).
VariousraptorsincludingAfricanfisheagles,a
MarOaleagle(Fig.13),andanAfricanharrierhawk
werecauseforalarmcallsamongstthewaterbirds.
Baboonswereseenpreyinguponeggswithin
nestsofthecolony(Fig.14).Atleastonecrocodile
wasseenlurkingbelowwaiOngforanyfledglingsthat
mightdropintothewatersbelow.
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Fig.13.MarOaleagle(photoTaraMassad)
Fig.12.Pink-backedpelicans(photoTaraMassad)
Fig.14.Baboonraidingnests(photoJasonDenlinger)
3.Discussion
Thebirdsnestedinopen,floodedwoodlanddominatedbyanatreesFaidherbiaalbida,fevertreesAcaciaxanthophloeaandpaper-barkacaciasA.sieberana.OnlyF.albidatrees(Fig.15)seemedtobeusedfornesOng(Stalmansetal2014).
DuringthemostrecentsurveyamaximumoffivenesOngspecieswererecordedperbreedingtree.Themaximumnumberofnestsrecordedforasingletreewas70,mostlyReedcormorants.
While51fewertreeswereusedfornesOngajerCycloneIdai(April2019)thanbeforethecyclone(March2019),therewasa56%increaseintheoverallnumberofnestscountedpost-cyclonewithoverhalfofthespeciesobservedincreasinginnumber.Furthermore,nofallentreesordebriswereobservedintheareaofthecolonyimplyingthatCycloneIdaihadnodirectimpactontheoverallnesOngofthecolony.
Total (all species) by survey No. of nests
No. of trees with nests
Average nests/tree
Max. nests per tree
7 Apr-14 5003 463 10.8 58
12 Mar-19 2432 434 5.6 45
14 Mar-19 Cyclone Idai makes landfall
16 Apr-19 3791 383 9.9 70
19
Fig.15.FloodedFaidherbiatreeswithnests(photoTaraMassad)
Table5.Totalwaterbirdnestsandtreeswithnestscountedineachsurveyforthesamecolony.
However,therewere24%fewertotalnestscounted
inApril2019comparedtoApril2014withoverhalfof
thespeciescounteddecreasinginnumber.WhilethemostrecentcountrevealedfarfewerReed
cormorants,theAfricanopenbillincreasedsignificantlycomparedto2014.
Assumingthateachnestrepresentedapairofbirds,theUremacolonycontainedapproximatelyjustover
7,500breedingwaterbirdsinApril2019comparedtoapproximately10,000inApril2014.
Perhapsthisdecreaseinwaterbirdscomparedto
the2014countwasimpactedbytheeffectsof
CycloneIdaioritmaybeanormalfluctuaOon
causedbyotherenvironmentalfactors.Eitherway
thispointstotheneedandimportanceofregular
countstoevaluatethestatusofthiswaterbird
breedingcolony.
Sincethe2014counttwospeciesconOnuetoexceed
the1%Ramsarcriterion.ThecountofAfricandarter
nestsof671(equaOngto1,342birds)exceedsthe1%Ramsarthresholdforthisspeciesinsouthernand
EasternAfrica(100birds;WetlandsInternaOonal2012).Despiteasmalldecreaseinthecountof
Yellow-billedstorkneststo896nests(equaOngto
1,792birds);thisnumberalsoexceedsthe1%Ramsarthresholdforsub-SaharanAfrica(1,000birds;
WetlandsInternaOonal2012).
TheimportanceofGorongosaNaOonalParkasa
conservaOonareaconOnuestobehighlightedbythepresenceofthismajorwaterbirdbreedingcolony.
20
4.References
STALMANSM.,DAVIESG.B.P.,TROLLIPJ.&POOLEG.2014.AmajorwaterbirdbreedingcolonyatLake
Urema,GorongosaNaOonalPark,Moçambique.DurbanNaturalScienceMuseumNovitates37:54-57.
UNITAR-UNOSAT.Mozambique,SofalaProvince.Imageryanalysis:19and20March2019,Published20
March2019,Version1.0.
WETLANDSINTERNATIONAL.2012.WaterbirdpopulaOonesOmates5:PopulaOondetails,esOmates,andtrends,www.wpe.wetlandsinternaOonal.org/lmaps
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5.Acknowledgements
Thetwowaterbirdnestcountsconductedin2019wouldnothavebeenpossiblewithoutinput
andassistanceofseveralpeople.Theauthors
wouldliketothankthefollowing:
• BoatcaptainTestMalungaforhiseffortinmaneuveringtheboataroundnesOngtreeswhilealsousinghisguidingknowledgetocountwaterbirdnests;
• CelinaDias,BertaGuambe,andJoséMonOnhofortheircontribuOonsincounOnganddatarecordingofnests.
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