​Test 1 - Reading - Passage 2​

​Mark Rowe investigates attempts to reintroduce elms to Britain​

​A.​​Around​​25​​million​​elms,​​accounting​​for​​90%​​of​​all​​elm​​trees​​in​​the​​UK,​​died​​during​​the​​1960s​​and​​'70s​​of​​Dutch​​elm​​disease.​​In​​the​​aftermath,​​the​​elm,​
​once​​so​​dominant​​in​​the​​British​​landscape,​​was​​largely​​forgotten.​​However,​​there's​​now​​hope​​the​​elm​​may​​be​​reintroduced​​to​​the​​countryside​​of​​central​
​and​​southern​​England.​​Any​​reintroduction​​will​​start​​from​​a​​very​​low​​base.​​'The​​impact​​of​​the​​disease​​is​​difficult​​to​​picture​​if​​you​​hadn't​​seen​​what​​was​
​there​​before,'​​says​​Matt​​Elliot​​of​​the​​Woodland​​Trust.​​'You​​look​​at​​old​​photographs​​from​​the​​1960s​​and​​it's​​only​​then​​that​​you​​realise​​the​​impact​​[elms​
​had] ... They were significant, large trees... then they were gone.'​

​B.​​The​​disease​​is​​caused​​by​​a​​fungus​​that​​blocks​​the​​elms'​​vascular​​(water,​​nutrient​​and​​food​​transport)​​system,​​causing​​branches​​to​​wilt​​and​​die.​​A​​first​
​epidemic,​ ​which​ ​occurred​ ​in​ ​the​ ​1920s,​ ​gradually​​died​​down,​​but​​in​​the​​'70s​​a​​second​​epidemic​​was​​triggered​​by​​shipments​​of​​elm​​from​​Canada.​​The​
​wood​ ​came​ ​in​ ​the​ ​form​ ​of​ ​logs​​destined​​for​​boat​​building​​and​​its​​intact​​bark​​was​​perfect​​for​​the​​elm​​bark​​beetles​​that​​spread​​the​​deadly​​fungus.​​This​
​time, the beetles carried a much more virulent strain that destroyed the vast majority of British elms.​

​C.​ ​Today,​ ​elms​ ​still​ ​exist​ ​in​ ​the​ ​southern​ ​English​ ​countryside​ ​but​ ​mostly​ ​only​ ​in​ ​low​ ​hedgerows​ ​between​ ​fields.​ ​'We​ ​have​ ​millions​ ​of​ ​small​ ​elms​ ​in​
​hedgerows​​but​​they​​get​​targeted​​by​​the​​beetle​​as​​soon​​as​​they​​reach​​a​​certain​​size,'​​says​​Karen​​Russell,​​co-author​​of​​the​​report​​'Where​​we​​are​​with​​elm'.​
​Once​​the​​trunk​​of​​the​​elm​​reaches​​10-15​​centimetres​​or​​so​​in​​diameter,​​it​​becomes​​a​​perfect​​size​​for​​beetles​​to​​lay​​eggs​​and​​for​​the​​fungus​​to​​take​​hold.​
​Yet​ ​mature​ ​specimens​ ​have​ ​been​ ​identified,​ ​in​ ​counties​ ​such​ ​as​ ​Cambridgeshire,​ ​that​ ​are​ ​hundreds​ ​of​ ​years​ ​old,​ ​and​ ​have​ ​mysteriously​​escaped​​the​
​epidemic.​

​The​ ​key,​ ​Russell​ ​says,​ ​is​ ​to​ ​identify​ ​and​ ​study​ ​those​ ​trees​ ​that​ ​have​ ​survived​ ​and​ ​work​ ​out​ ​why​ ​they​ ​stood​ ​tall​ ​when​ ​millions​ ​of​ ​others​ ​succumbed.​
​Nevertheless,​​opportunities​​are​​limited​​as​​the​​number​​of​​these​​mature​​survivors​​is​​relatively​​small.​​'What​​are​​the​​reasons​​for​​their​​survival?'​​asks​​Russell.​
​'Avoidance, tolerance, resistance? We don't know where the balance lies between the three. I don't see how it can be entirely down to luck.'​

​D.​ ​For​ ​centuries,​ ​elm​ ​ran​ ​a​ ​close​ ​second​ ​to​ ​oak​ ​as​ ​the​ ​hardwood​ ​tree​ ​of​ ​choice​ ​in​ ​Britain​ ​and​ ​was​ ​in​​many​​instances​​the​​most​​prominent​​tree​​in​​the​
​landscape.​​Not​​only​​was​​elm​​common​​in​​European​​forests,​​it​​became​​a​​key​​component​​of​​birch,​​ash​​and​​hazel​​woodlands.​​The​​use​​of​​elm​​is​​thought​​to​
​go​ ​back​​to​​the​​Bronze​​Age,​​when​​it​​was​​widely​​used​​for​​tools.​​Elm​​was​​also​​the​​preferred​​material​​for​​shields​​and​​early​​swords.​​In​​the​​18th​​century,​​it​
​was​​planted​​more​​widely​​and​​its​​wood​​was​​used​​for​​items​​such​​as​​storage​​crates​​and​​flooring.​​It​​was​​also​​suitable​​for​​items​​that​​experienced​​high​​levels​
​of impact and was used to build the keel of the 19th-century sailing ship Cutty Sark as well as mining equipment.​

​E.​ ​Given​ ​how​ ​ingrained​ ​elm​ ​is​ ​in​ ​British​ ​culture,​ ​it's​ ​unsurprising​ ​the​ ​tree​ ​has​ ​many​ ​advocates.​ ​Amongst​ ​them​ ​is​ ​Peter​ ​Bourne​ ​of​ ​the​ ​National​ ​Elm​
​Collection​​in​​Brighton.​​'I​​saw​​Dutch​​elm​​disease​​unfold​​as​​a​​small​​boy,'​​he​​says.​​'The​​elm​​seemed​​to​​be​​part​​of​​rural​​England,​​but​​I​​remember​​watching​
​trees​ ​just​ ​lose​ ​their​ ​leaves​ ​and​ ​that​ ​really​ ​stayed​ ​with​ ​me.'​ ​Today,​ ​the​ ​city​ ​of​ ​Brighton's​ ​elms​ ​total​ ​about​ ​17,000.​ ​Local​ ​factors​ ​appear​ ​to​ ​have​
​contributed​​to​​their​​survival.​​Strong​​winds​​from​​the​​sea​​make​​it​​difficult​​for​​the​​determined​​elm​​bark​​beetle​​to​​attack​​this​​coastal​​city's​​elm​​population.​
​However, the situation is precarious. 'The beetles can just march in if we're not careful, as the threat is right on our doorstep,' says Bourne.​

​F.​​Any​​prospect​​of​​the​​elm​​returning​​relies​​heavily​​on​​trees​​being​​either​​resistant​​to,​​or​​tolerant​​of,​​the​​disease.​​This​​means​​a​​widespread​​reintroduction​
​would​​involve​​existing​​or​​new​​hybrid​​strains​​derived​​from​​resistant,​​generally​​non-native​​elm​​species.​​A​​new​​generation​​of​​seedlings​​have​​been​​bred​​and​
​tested​​to​​see​​if​​they​​can​​withstand​​the​​fungus​​by​​cutting​​a​​small​​slit​​on​​the​​bark​​and​​injecting​​a​​tiny​​amount​​of​​the​​pathogen.​​'The​​effects​​are​​very​​quick,'​
​says​​Russell.​​'You​​return​​in​​four​​to​​six​​weeks​​and​​trees​​that​​are​​resistant​​show​​no​​symptoms,​​whereas​​those​​that​​are​​susceptible​​show​​leaf​​loss​​and​​may​
​even have died completely.'​

​G.​​All​​of​​this​​raises​​questions​​of​​social​​acceptance,​​acknowledges​​Russell.​​'If​​we're​​putting​​elm​​back​​into​​the​​landscape,​​a​​small​​element​​of​​it​​is​​not​​native​
​-​​are​​we​​bothered​​about​​that?'​​For​​her,​​the​​environmental​​case​​for​​reintroducing​​elm​​is​​strong.​​'They​​will​​host​​wildlife,​​which​​is​​a​​good​​thing.​​Others​​are​
​more​​wary.​​'On​​the​​face​​of​​it,​​it​​seems​​like​​a​​good​​idea,'​​says​​Elliot.​​The​​problem,​​he​​suggests,​​is​​that,​​'You're​​replacing​​a​​native​​species​​with​​a​​horticultural​
​analogue*.​ ​You're​ ​effectively​ ​cloning.'​ ​There's​ ​also​ ​the​ ​risk​ ​of​ ​introducing​ ​new​ ​diseases.​ ​Rather​ ​than​ ​plant​ ​new​ ​elms,​​the​​Woodland​​Trust​​emphasises​
​providing​​space​​to​​those​​elms​​that​​have​​survived​​independently.​​'Sometimes​​the​​best​​thing​​you​​can​​do​​is​​just​​give​​nature​​time​​to​​recover​​over​​time,​​you​
​might get resistance,' says Elliot.​

​●​ ​horticultural analogue: a cultivated plant species that is genetically similar to an existing species​
​Test 1 - Reading - Passage 1​

​The kākāpō​
​The kākāpō is a nocturnal, flightless parrot that is critically endangered and one of New Zealand's unique treasures.​
​The​ ​kākāpō,​ ​also​ ​known​ ​as​ ​the​ ​owl​ ​parrot,​ ​is​ ​a​ ​large,​ ​forest-dwelling​ ​bird,​ ​with​ ​a​ ​pale​ ​owl-like​ ​face.​ ​Up​ ​to​ ​64​ ​cm​ ​in​ ​length,​ ​it​ ​has​
​predominantly​ ​yellow-green​ ​feathers,​ ​forward-facing​ ​eyes,​ ​a​ ​large​ ​grey​ ​beak,​ ​large​ ​blue​ ​feet,​ ​and​ ​relatively​ ​short​ ​wings​ ​and​ ​tail.​​It​​is​​the​
​world's only flightless parrot, and is also possibly one of the world's longest-living birds, with a reported lifespan of up to 100 years.​
​Kākāpō​ ​are​ ​solitary​ ​birds​ ​and​ ​tend​ ​to​ ​occupy​ ​the​ ​same​ ​home​ ​range​​for​​many​​years.​​They​​forage​​on​​the​​ground​​and​​climb​​high​​into​​trees.​
​They​ ​often​ ​leap​​from​​trees​​and​​flap​​their​​wings,​​but​​at​​best​​manage​​a​​controlled​​descent​​to​​the​​ground.​​They​​are​​entirely​​vegetarian,​​with​
​their diet including the leaves, roots and bark of trees as well as bulbs, and fern fronds.​
​Kākāpō​ ​breed​ ​in​ ​summer​ ​and​ ​autumn,​​but​​only​​in​​years​​when​​food​​is​​plentiful.​​Males​​play​​no​​part​​in​​incubation​​or​​chick-rearing​​-​​females​
​alone​ ​incubate​ ​eggs​ ​and​ ​feed​ ​the​ ​chicks.​ ​The​ ​1-4​ ​eggs​ ​are​ ​laid​ ​in​ ​soil,​ ​which​ ​is​ ​repeatedly​ ​turned​ ​over​ ​before​ ​and​ ​during​ ​incubation.​​The​
​female​​kākāpō​​has​​to​​spend​​long​​periods​​away​​from​​the​​nest​​searching​​for​​food,​​which​​leaves​​the​​unattended​​eggs​​and​​chicks​​particularly​
​vulnerable to predators.​
​Before​ ​humans​ ​arrived,​ ​kākāpō​ ​were​ ​common​ ​throughout​ ​New​ ​Zealand's​ ​forests.​ ​However,​ ​this​ ​all​ ​changed​ ​with​ ​the​ ​arrival​ ​of​ ​the​ ​first​
​Polynesian​​settlers​​about​​700​​years​​ago.​​For​​the​​early​​settlers,​​the​​flightless​​kākāpō​​was​​easy​​prey.​​They​​ate​​its​​meat​​and​​used​​its​​feathers​
​to​ ​make​ ​soft​​cloaks.​​With​​them​​came​​the​​Polynesian​​dog​​and​​rat,​​which​​also​​preyed​​on​​kākāpō.​​By​​the​​time​​European​​colonisers​​arrived​​in​
​the​​early​​1800s,​​kākāpō​​had​​become​​confined​​to​​the​​central​​North​​Island​​and​​forested​​parts​​of​​the​​South​​Island.​​The​​fall​​in​​kākāpō​​numbers​
​was​ ​accelerated​ ​by​ ​European​ ​colonisation.​ ​A​ ​great​ ​deal​ ​of​ ​habitat​​was​​lost​​through​​forest​​clearance,​​and​​introduced​​species​​such​​as​​deer​
​depleted​ ​the​ ​remaining​ ​forests​​of​​food.​​Other​​predators​​such​​as​​cats,​​stoats​​and​​two​​more​​species​​of​​rat​​were​​also​​introduced.​​The​​kākāpō​
​were in serious trouble.​
​In​​1894,​​the​​New​​Zealand​​government​​launched​​its​​first​​attempt​​to​​save​​the​​kākāpō.​​Conservationist​​Richard​​Henry​​led​​an​​effort​​to​​relocate​
​several​ ​hundred​ ​of​ ​the​ ​birds​ ​to​ ​predator-free​ ​Resolution​ ​Island​ ​in​ ​Fiordland.​ ​Unfortunately,​ ​the​ ​island​ ​didn't​ ​remain​ ​predator​ ​free​ ​-​​stoats​
​arrived​ ​within​ ​six​ ​years,​ ​eventually​ ​destroying​ ​the​ ​kākāpō​ ​population.​ ​By​​the​​mid-1900s,​​the​​kākāpō​​was​​practically​​a​​lost​​species.​​Only​​a​
​few clung to life in the most isolated parts of New Zealand.​
​From​​1949​​to​​1973,​​the​​newly​​formed​​New​​Zealand​​Wildlife​​Service​​made​​over​​60​​expeditions​​to​​find​​kākāpō,​​focusing​​mainly​​on​​Fiordland.​
​Six​ ​were​ ​caught,​ ​but​ ​there​ ​were​ ​no​ ​females​​amongst​​them​​and​​all​​but​​one​​died​​within​​a​​few​​months​​of​​captivity.​​In​​1974,​​a​​new​​initiative​
​was​ ​launched,​ ​and​ ​by​ ​1977,​ ​18​ ​more​ ​kākāpō​ ​were​​found​​in​​Fiordland.​​However,​​there​​were​​still​​no​​females.​​In​​1977,​​a​​large​​population​​of​
​males​ ​was​ ​spotted​ ​in​ ​Rakiura,​ ​a​ ​large​ ​island​ ​free​ ​from​ ​stoats,​ ​ferrets​ ​and​ ​weasels.​ ​There​ ​were​ ​about​ ​200​ ​individuals,​ ​and​ ​in​ ​1980​ ​it​ ​was​
​confirmed females were also present. These birds have been the foundation of all subsequent work in managing the species.​
​Unfortunately,​​predation​​by​​feral​​cats​​on​​Rakiura​​Island​​led​​to​​a​​rapid​​decline​​in​​kākāpō​​numbers.​​As​​a​​result,​​during​​1980-97,​​the​​surviving​
​population​​was​​evacuated​​to​​three​​island​​sanctuaries:​​Codfish​​Island,​​Maud​​Island​​and​​Little​​Barrier​​Island.​​However,​​breeding​​success​​was​
​hard​ ​to​ ​achieve.​ ​Rats​ ​were​ ​found​ ​to​ ​be​ ​a​ ​major​ ​predator​ ​of​ ​kākāpō​ ​chicks​ ​and​ ​an​ ​insufficient​ ​number​ ​of​ ​chicks​ ​survived​ ​to​ ​offset​ ​adult​
​mortality.​ ​By​ ​1995,​ ​although​ ​at​ ​least​ ​12​ ​chicks​ ​had​ ​been​ ​produced​ ​on​ ​the​ ​islands,​ ​only​ ​three​ ​had​ ​survived.​ ​The​ ​kākāpō​ ​population​ ​had​
​dropped to 51 birds. The critical situation prompted an urgent review of kākāpō management in New Zealand.​
​In​ ​1996,​ ​a​ ​new​ ​Recovery​ ​Plan​ ​was​​launched,​​together​​with​​a​​specialist​​advisory​​group​​called​​the​​Kākāpō​​Scientific​​and​​Technical​​Advisory​
​Committee​​and​​a​​higher​​amount​​of​​funding.​​Renewed​​steps​​were​​taken​​to​​control​​predators​​on​​the​​three​​islands.​​Cats​​were​​eradicated​​from​
​Little​ ​Barrier​ ​Island​ ​in​ ​1980,​ ​and​ ​possums​ ​were​ ​eradicated​​from​​Codfish​​Island​​by​​1986.​​However,​​the​​population​​did​​not​​start​​to​​increase​
​until​​rats​​were​​removed​​from​​all​​three​​islands,​​and​​the​​birds​​were​​more​​intensively​​managed.​​This​​involved​​moving​​the​​birds​​between​​islands,​
​supplementary feeding of adults and rescuing and hand-raising any failing chicks.​
​After​ ​the​ ​first​ ​five​ ​years​ ​of​ ​the​ ​Recovery​ ​Plan,​ ​the​ ​population​ ​was​ ​on​ ​target.​ ​By​​2000,​​five​​new​​females​​had​​been​​produced,​​and​​the​​total​
​population​​had​​grown​​to​​62​​birds.​​For​​the​​first​​time,​​there​​was​​cautious​​optimism​​for​​the​​future​​of​​kākāpō​​and​​by​​June​​2020,​​a​​total​​of​​210​
​birds was recorded.​
​Today,​​kākāpō​​management​​continues​​to​​be​​guided​​by​​the​​kākāpō​​Recovery​​Plan.​​Its​​key​​goals​​are:​​minimise​​the​​loss​​of​​genetic​​diversity​​in​
​the​ ​kākāpō​ ​population,​ ​restore​ ​or​ ​maintain​ ​sufficient​ ​habitat​​to​​accommodate​​the​​expected​​increase​​in​​the​​kākāpō​​population,​​and​​ensure​
​stakeholders continue to be fully engaged in the preservation of the species.​