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四级考前冲刺试题三WorkingtoImprovetheConditionsofEvergladesNationalParkWhenmanypeoplethinkofFlorida,imagesofsandycoastlinesorthemeparkridescometomind.ButaboutanhoursouthofMiamiliesanaturalwilderness(野生地)differentfromanywhereelseintheUnitedStates.EvergladesNationalParkisthelargestsubtropicalwildernessinthecountry.Theparkishometoseveralrareandendangeredspecies.Itisalsothethirdlargestnationalparkinthelowerforty-eightstates,afterDeathValleyandYellowstone.MorethanonemillionpeoplevisittheEvergladeseachyear.WildlifeReservesTheEvergladesisconsideredoneofthegreatbiologicalwondersoftheworld.Theexpansivewetlandsstretchacrossmorethan600,000hectares(公顷).ItisaplacewhereplantsandanimalsfromtheCaribbeanSeashareanecosystem(生态系统)withnativeNorthAmericanspecies.Unlikemostothernationalparks,EvergladesNationalParkwascreatedtoprotectanecosystemfromdamage.TheEvergladesishometo36speciesthatareconsideredthreatenedorprotected.TheyincludetheFloridapanther,theAmericancrocodile(鳄鱼)andtheWestIndianmanatee.Inaddition,morethan350birdspeciesand300speciesoffreshandsaltwaterfishlivewithinthepark.TheEvergladesisalsohometofortyspeciesofmammals(哺乳动物)andfiftyreptile(爬行动物)species.ExoticplantscanalsobefoundintheEverglades.Theyincludewhatissaidtobethelargestgrowthofmangrovetreesinthewesternhalfoftheworld.Gumbo-limbotrees,knownfortheirpeelingredskin,stranglerfigsandroyalpalmsarealsoamongthearea’splantlife.TheEvergladesisalsohometothecountry’slargestlivingmahoganytree.Sawgrassgrowsinsomeareasofthepark.Becareful—itisverysharp,withteethjustlikeasaw.Itcangrowuptofourmeterstall.Withabout1.5metersofrainfalleachyear,plantsandtreesneverstopgrowingintheEverglades.Wanttovisitit?Thedry,winterseasonisthefavoriteofmostvisitors,wheninsectslikemosquitoesarelessofaproblem.TherainyseasonlastsfromJunetoNovember.TherearemanywaystoexploretheEverglades.Visitorscouldseealligators(anAmericancrocodile)whilehikingtheAnhingaTrail.TheEvergladesistheonlyplaceonEarthwherefreshwatercrocodilesandsaltwatercrocodilesliveinthesamearea.Visitorsusingcanoesorairboatsarelikelytoseelargegroupsofwadingbirds(涉水鸟)likethewoodstorkorgreatblueheron.Itisevenpossibletoseeflamingos(火烈鸟)intheEverglades.SomemightenjoyridingbicyclesthroughSharkValley,whileothersmaywanttomoveslowlythroughshallowwaterswhereinsectsandwildlifecanbeseenup-close.Parkguidesalsoleadvisitorsontourswithtramcars.Thisspring,EvergladesNationalParklaunchedavisitation(探访)programtowhatwasonceahighlyrestrictedmilitarybase.Parkofficialsareworkingtorecoveramissilebaseusedinthe1960s.ThebaseplayedapartinthenucleartensionsbetweentheUnitedStatesandtheSovietUnion.ThegovernmentbuilttheFloridabaseshortlyafterthediscoveryofSovietmissilesabout300kilometersaway,ontheislandofCuba.TensionswerehighduringtheCubanmissilecrisis.ButmissilesstoredattheAmericanbasewereneverfired.Thebasewasclosedandallmissileequipmentwasremovedinthe1970s.Todayonlythebuildingsremain.Thisyear,thehistoricareahadmanyvisitors,includingformerAmericanservicememberswhorememberthemissilecrisis.Theparkhopestooffermoretripsnextspring,tohelpsupportthehistoryforthosewholivedthroughitandforfuturegenerations.ThreatsitfacesExpertssaychangestotheEvergladesarethreateningseveraldifferentkindsofwildlife.TheysaythethreatsarearesultofactionstheUnitedStatesgovernmentbeganmorethanfiftyyearsago,andsettlersbeganevenearlier.TheNationalParkServicesaysearlycolonialsettlersandlanddevelopersthoughttheEvergladeshadlittlevalue.Thesettlershadplanstoremovewaterfromtheareaandinthe1880sdevelopersbegandiggingdrainagecanals.Atthetime,theydidnotunderstandthecomplexityoftheEverglades’ecosystem.Asaresult,theywerenotpreparedforalltheworkandcausedenvironmentalproblems.Theecosystem,however,wasabletosurvive.Evenlargereffortstodrainthewetlandscontinuedbetween1905and1910.Largeareaswerechangedtofarmland.Thisledtoincreaseddevelopment,withmorepeoplemovingtotheEvergladesandalsomorevisitors.Morechangescamein1948,whenCongressapprovedtheCentralandSouthFloridaProject.Aspartoftheplan,theArmyCorpsofEngineersbuiltroads,canalsandwater-controlsystemsthroughoutSouthFlorida.Theaimoftheprojectwastoprovidewaterandfloodprotectionfordevelopedareasandagriculture.WorkersbuiltahugesystemofwaterwaysandpumpingstationstocontroltheoverflowofLakeOkeechobee,northoftheEverglades.Today,fiftypercentofsouthFlorida’searlywetlandareasnolongerexist.Populationsofwadingbirdshavebeenreducedbyninetypercent.Wholepopulationsofanimalsareindangerofdisappearing.Theendangeredcreaturesincludethemanatee,theMiamiblackheadsnake,thewoodstorkandtheFloridapanther.Inrecentyears,environmentalexpertshavelearnedaboutthedamagetotheEverglades.Theysaythenaturalbalanceofplantsandanimalshasbeendestroyed.Recently,theObamaadministrationpromised$360,000,000topayforEvergladesrestorationthisyear.TheadministrationisalsoaskingthatCongressapproveanadditional$278,000,000fornextyear.Themoneywillhelptosupportprojectsapprovedbythegovernmentnineyearsago.TheprojectsincludeimprovingwetlandsinthePicayuneStrandinSouthwestFloridaandrepairstoLakeOkeechobee’sdam.Untilnow,thestateofFloridahasspentthemostmone