Don't Count on Dung

　　Conservationists（自然保護主義者）may be miscalculating the numbers of the threatened animals such as elephants．say African and American researchers．The error occurs because of a flaw in the way they estimate animal numbers from the piles of dung（糞）the creatures leave behind．

　　The mistake could 1ead researchers to think that there are twice as many elephants as there really are in some regions according to Andrew Plumptre of the Wildlife Conservation Society（wcs） in New York

　　Biologist Katy Payne of Cornell University in Ithaca，New York，agrees．''We really need to know elephant numbers and the evidence that we have is quite indirect，“says Payne，who electronically tracks elephants

　　Counting elephants from planes is impossible in the vast rainforests of Central Africa．So researchers often estimate elephant numbers by counting dung piles in a given area．They also need to know the rate at which dung decays Because it's extremely difficult to determine these rates．however，researchers counting elephants in one region tend to rely on standard decay rates established elsewhere

　　But researchers at the WCS have found that this decay rate varies from region to region depending on the climate and environment Using the wrong values can lead the census astray（離開正道），says Plumptre

　　He and his colleague Anthony Chifu Nchanji studied decaying elephant dung in the forests of Cameroon They found that the dung decayed between 55 and 65 per cent more slowly than the dung in the rainforests of neighbouring Gabon．If researchers use decay rates from Gabon to count elephants in Cameroon，they would probably find more elephants than are actually around．This could mean estimates in Cameroon are at least twice as high as those derived from decay rates calculated locally，says Plumptre“However accurate your dung density estimate might be．the decay rate can severely affect the result”

　　Plumptre also says that the dung—pile census should be carried out over a region similar in size to an elephant's natural range The usual technique of monitoring only small，protected areas distorts numbers because elephants move in and out of these regions，he says“If the elephant population increases within the protected area，you can not determine whether 1t is a real increase or whether it is due to elephants moving in because they are being poached（入侵偷獵）outside．”

　　Plumptre says that similar problems may also affect other animal census studies that rely on indirect evidence such as nests，tracks or burrows（地洞）

　　36 The word“threatened”in the first sentence of the first paragraph could be best replaced by

　　A “endangered”

　　B “frightened”

　　C “killed”

　　D “angered”

　　37 Why do researchers estimate elephant numbers in an area by counting dung piles?

　　A Because elephants are difficult to catch

　　B Because it is not possible to count elephants from a plane．

　　C Because it is not possible to keep track of elephants．

　　D Because elephants are shy animals

　　38 Piles of dung can't be relied upon when it comes to estimating elephant numbers because

　　A they are different in size

　　B they scatter an over the region．

　　C they are different in decay rate．

　　D they are different in quality．

　　39 According to Plumptre，the region over which a dung—pile census is carried out should be

　　A small enough

　　B well protected．

　　C carefully monitored．

　　D large enough

　　40 The first word“He”in paragraph 6 refers to

　　A Andrew Plumptre

　　B Katy Payne．

　　C Anthony Chifu Nchanji．

　　D the writer of the article．

　　參考答案

　　36 A threatened：有滅絕危險的。threatened animals：有滅絕危險的動物。endangered：有滅絕危險的；有生命危險的。an endangered species：一個有滅絕危險的物種。frightened：受驚的。killed：殺死了的。angered：激怒了的。

　　37 B 該題問的是：為什么研究人員通過數(shù)糞堆估計一個地區(qū)的象數(shù)?第三段有這么一個句子，意思是說：從飛機上數(shù)中非廣闊的赤道雨林中的象是不可能的，研究人員通過數(shù)糞堆估計一個特定地區(qū)的糞堆估計該區(qū)域的象數(shù)。因此B是正確答案。

　　38 c 該題問的是：不可依據(jù)糞堆數(shù)估計象數(shù)的原因是什么?文章第五段第一句話是這么說的：……這種取決于氣候和環(huán)境的腐爛速率在不同的地區(qū)是不一樣的。可見c是正確的答案。A說的是：它們的大小是不一樣的。B說的是：它們散布在整個地區(qū)。D說的是：它們的質(zhì)量是不一樣的。

　　39 D 該題問的是：根據(jù)Plumptre的觀點，選擇糞堆普查的地區(qū)應(yīng)符合什么樣的條件?倒數(shù)第二段提到了P1umDtre的觀點，即普查的地區(qū)應(yīng)該大到不能使象自由出入，也就是說，必須足夠大。A說的是：足夠小。B說的是：得到了很好的保護。c說的是：得到了密切的監(jiān)控。

　　40 A 該題問的是?第六段的第一個詞“He”指誰?一般情況下，代詞回指的詞必須離得很近。因此必定是“Andrewr Pqumptre”。

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