EcologicalassessmentofCheffaWetlandintheborkenaval

EcologicalIndicators15(2012)63–71ContentslistsavailableatSciVerseScienceDirectEcologicalIndicatorsjournalhomepage::MacroinvertebrateandbirdcommunitiesMelakuGetachewa,ArgawAmbelub,∗,SeidTikub,WorkuLegessec,AynalemAdugnad,HelmutKlooseaAmharaNationalRegionalState,OromiaZoneHealthDepartment,P.O.Box21,Kemise,EthiopiabDepartmentofEnvironmentalHealthSciencesandTechnology,JimmaUniversity,P.O.Box378,Jimma,EthiopiacTREEFoundation,P.O.Box48839,Sarasota,FL34230,USAdDepartmentofGeography,SonomaStateUniversity,RohnertPark,CA94928,USAeDepartmentofEpidemiologyandBiostatistics,UniversityofCalifornia,Box0560,185BerryStreet,SanFrancisco94143-0560,USAarticleinfoArticlehistory:Received1October2010Receivedinrevisedform2September2011Accepted19September2011Keywords:CheffaWetlandCanonicalcorrespondenceanalysisDiversityindexHabitatconditionHumanimpactabstractAcomparativestudyofmacroinvertebratesandbirdcommunitieswasundertakentoassesstheecologi-calintegrityandhumanimpactinCheffaWetland,northeasternEthiopia.ThestudywasundertakenfromFebruarytoMay2010.Physicochemicalparametersofthewater,birds,macroinvertebratesandhumanimpactclasseswereassessedat10sitesinthewetlandexposedtodifferentanthropogenicactivities.WehavecomparedShannonindexofdiversityofmacroinvertebratesandbirdsalongwithdifferenthabitatclasses.Multivariatestatisticswereusedtoextractthemaindrivingforcesforchangesinmacroinverte-brateandbirdcommunitypatternsoutofacomplexdataset.Subsequently,wecomparedthediversityindicesofthemacroinvertebrateandbirdcommunitiesforthedetectionofhumanimpacts.Atotalof2789macroinvertebratesbelongingto34familiesin10orderswerecollectedand3128birdsbelongingto57speciesrecorded.Macroinvertebratesbelongedtofivedifferentorders:Hemiptera(sevenfamilies),Coleoptera(fivefamilies),Odonata(fivefamilies),Gastropoda(sevenfamilies)andDiptera(fivefamilies),exceeding77%oftheoverallsample.Abundanceanddiversityofthebirdandmacroinvertebratecommu-nitieswererelatedmainlytoconcentrationsofDO,nitrateandchloride,habitatconditions,andhumandisturbances.Ofthe57speciesofbirdsrecorded,thecattleegret(Bubulcusibis),white-facedwhistlingducks(Dendrocygnaviduata),Egyptiangoose(Alopochenaegyptiacus)andspur-wingedlapwing(Vanel-lussuperciliosus)werethemostabundant.Thephysicochemicalvariablesshowedgreatvariationamongsites.Theresultsrevealedthathumaninterferenceinwetlandmayresultinseriousecologicalimbalancesinthenaturallifecycleandimpactonhumanwelfare.Long-termstudiesarerequiredtopredictchangesinwetlandecologyandpopulationdynamics,withtheobjectiveofdevelopingappropriatemeasuresbyfederal,regionalandlocalstakeholderstoensurewetlandrestorationandsustainability.©2011ElsevierLtd.Allrightsreserved.1.IntroductionWetlandsareareasofmarsh,pondsandswamps,whethernat-uralorartificial,permanentortemporary,withwaterthatisstaticorflowing,fresh,brackishorsalty,includingareasofmarinewater,thedepthofwhichatlowtidedoesnotexceededsixmeters(SivaperumanandJayson,2000;Kafle,2006).Fivemajorwetlandcategoriesarerecognized,namelymarine,estuarine,lacustrine,riverineandpalustrine(FAO,2008;WWD,2009).WetlandscontributeindiversewaystothelivelihoodofmanypeopleandbiodiversityinAfrica.OneofthemajorconstraintstothejudicioususeofAfricanwetlandsislackofknowledgebyplannersandnaturalresourcemanagersofthebenefitsthatthey∗Correspondingauthor.Tel.:[phone].E-mailaddresses:[e-mail],[e-mail](A.Ambelu).provideandtechniquesbywhichtheycanbeutilizedinasustain-ablemanner(JogoandHassan,2010).Consequently,owingtoalackofscientificinvestigationandinconsistentmappingpoliciesinAfrica,thetotalextentofwetlandsonthecontinentisstillunknown(Schuyt,2005).Atotalof77wetlandshavebeenidentifiedinEthiopiaandEritrea(Abebe,2003).InEthiopia,wetlandsarelocatedinalmostallecologicalandaltitudinalrangescoveringapproxi-mately2%(22,600km2)ofthecountry’stotalsurfacearea(EWNRA,2008).Freshwaterecosystemshavelostagreaterproportionoftheirspeciesandhabitatthanecosystemsonlandorintheoceans(MEA,2005;EWNRA,2008).Whilewetlandsareamongthemostpro-ductiveecosystems,theyarealsothemostthreatened(Abebe,2003).Inaddition,decision-makersatmanylevelsareunawareoftheconnectionbetweenwetlandconditionandtheprovisionofwetlandservicesandtheconsequentbenefitsforpeople(MEA,2005;Schuyt,2005).ManywetlandsinEasternAfricahavecomeunderextremepressureasgovernmentpolicies,socio-economic1470-160X/$–seefrontmatter©2011ElsevierLtd.Allrightsreserved.doi:10.1016/j.ecolind.2011.09.01164M.Getachewetal./EcologicalIndicators15(2012)63–71changeandpopulationincreasehavestimulatedaneedformoreagriculturallyproductiveandurbanland.Seasonalwetlandusebypastoralistsandtheirlivestockisincreasinglyaddingtotheanthro-pogenicimpactsduetoreductionanddegradationofpasturesandwaterresourcesandexpansionofthecultivatedarea(HongoandMasikini,2003).Asaresult,wetlandshavebeenencroachedanddegradedinmanycountries.AlargenumberofwetlandsinEthiopiaareconsideredvulnerablezonesandsomeofthemostexploitedandmismanagedoneshavelos