1、tourists-have been picking leaves and cutting their names on the tree-trunk. so far, not one of them has been struck down by sudden death!   lesson59 in or out ？ 進(jìn)來(lái)還是出去？ our dog, rex, used to sit outside our front gate and bark. every time he wanted to come into the garden he wou

2、ld bark until someone opened the gate. as the neighbours complained of the noise, my husband spent weeks training him to press his paw on the latch to let himself in. rex soon became an expert at opening the gate. however, when i was going out shopping last week, i noticed him in the garden near the

3、 gate. this time he was barking so that someone would let him out ! since then, he has developed another bad habit. as soon as he opens the gate from the outside, he comes into the garden and waits until the gate shuts. then he sits and barks until someone lets him out. after this he immediately let

4、s himself in and begins barking again. yesterday my husband removed the gate and rex got so annoyed we have not seen him since.      lesson60 the future 卜算未來(lái) at a village fair, i decided to visit a fortune-teller called madam bellinsky. i went into her tent and she told

5、 me to sit down. after i had given her some money, she looked into a crystal ball and said: 'a relation of yours is coming to see you. she will be arriving this evening and intends to stay for a few days. the moment you leave this tent, you will get a big surprise. a woman you know well will rus

6、h towards you. she will speak to you and then she will lead you away from this place. that is all.' as soon as i went outside, i forgot all about madam bellinsky because my wife hurried towards me. 'where have you been hiding ?' she asked impatiently. 'your sister will be here in les

7、s than an hour and we must be at the station to meet her. we are late already.' as she walked away, i followed her out of the fair.    lesson61 trouble with the hubble 哈勃望遠(yuǎn)鏡的困境 in future, astronauts will be required to descend from a spaceship while it is still in space and t

8、o return to it. the ability to do this will be necessary in future flights to distant planets. scientists are now trying to discover if this is possible. the spaceship astra which left the earth a short time ago, will be travelling three hundred miles into space. at a certain point, the astra will s

9、top for a short time and an astronaut will attempt to leave the stationary spaceship and then return to it. we shall not know whether the experiment has been successful until we have received a radio message. the first message is expected to arrive at 7 o'clock this evening. by that time, the as

10、tra will have been flying through space for seventeen hours and will have circled the earth a great many times. when the first radio messages have been received, the results of the trip will be announced immediately.   lesson62 after the fire 大火之后 firemen had been fighting the fo

11、rest fire for nearly three weeks before they could get it under control. a short time before, great trees had covered the countryside for miles around. now, smoke still rose up from the warm ground over the desolate hills. winter was coming on and the hills threatened the surrounding villages with d

12、estruction, for heavy rain would not only wash away the soil but would cause serious floods as well. when the fire had at last been put out, the forest authorities ordered several tons of a special type of grass-seed which would grow quickly. the seed was sprayed over the ground in huge quantities b

13、y aeroplanes. the planes had been planting seed for nearly a month when it began to rain. by then, however, in many places the grass had already taken root. in place of the great trees which had been growing there for centuries, patches of green had begun to appear in the blackened soil.   

14、; lesson63 she was not amused 她并不覺得好笑 geoffrey hampden has a large circle of friends and is very popular at parties. everybody admires him for his fine sense of humor-everybody, that is, except his six-year-old daughter, jenny. recently, one of geoffrey's closest friends asked him to m

15、ake a speech at a wedding reception. this is the sort of thing that geoffrey loves. he prepared the speech carefully and went to the wedding with jenny. he had included a large number of funny stories in the speech and, of course, it was a great success. as soon as he had finished, jenny told him sh

16、e wanted to go home. geoffrey was a little disappointed by this but he did as his daughter asked. on the way home, he asked jenny if she had enjoyed the speech. to his surprise, she said she hadn't. geoffrey asked her why this was so and she told him that she did not like to see so many people l

17、aughing at him!   lesson64 the channel tunnel 海峽隧道 in l858, a french engineer, aime thome de gamond, arrived in england with a plan for a twenty-one mile tunnel across the english channel. he said that it would be possible to build a platform in the centre of the channel. this pl

18、atform would serve as a port and a railway station. the tunnel would be well-ventilated if tall chimneys were built above sea-level. in 1860, a better plan was put forward by an englishman, william low. he suggested that a double railway tunnel should be built. this would solve the problem of ventil

19、ation, for if a train entered this tunnel, it would draw in fresh air behind it. forty-two years later a tunnel was actually begun. if, at the time, the british had not feared invasion, it would have been completed. recently, there has again been great interest in the idea of a channel tunnel. if it

20、 is built, it will connect britain to europe for the first time in history.   lesson65 jumbo versus the police 小象對(duì)警察 last christmas, the circus owner, jimmy gates, decided to take some presents to a children's hospital. dressed up as father christmas and accompanied by a '

21、;guard of honour' of six pretty girls, he set off down the main street of the city riding a baby elephant called jumbo. he, should have known that the police would never allow this sort of thing. a policeman approached jimmy and told him he ought to have gone along a side-street as jumbo was hol

22、ding up the traffic. though jimmy agreed to go at once, jumbo refused to move. fifteen policemen had to push very hard to get him off the main street. the police had a difficult time, but they were most amused. 'jumbo must weigh a few tons,' said a policeman afterwards, 'so it was fortun

23、ate that we didn't have to carry him. of course, we should arrest him, but as he has a good record, we shall let him off this time.'   lesson66 sweet as honey! 像蜜一樣甜！ the hatheld puffin is a modern aero-plane, but its designer, mr john wimpenny, is finding it difficult to

24、 get it off the ground. the reason for this is that this plane is also a bicycle. its pilot has to pedal hard to get it into the air. after mr wimpenny had the plane built, it was tested thoroughly. in 1961, it was the first man-powered aircraft to fly half a mile. while being flown by a champion am

25、ateur cyclist in 1963, the plane crashed on an airfield. since then, mr wimpenny has had it rebuilt. he has had the length of the wings increased so that they now measure 93 feet-almost as long as those of a dakota. many people have shown interest in this new and unusual sport. but though air cyclis

26、ts may learn how to fly over short distances, and may, eventually, even get across the english channel, it is doubtful whether they will ever cycle across the atlantic.   lesson67 volcanoes 火山 haroun tazieff the polish scientist, has spent his life-time studying active volcanoes

27、and deep caves in all parts of the world. in 1948, he went to lake kivu in the congo to observe a new volcano which he later named kituro. tazieff was able to set up his camp very close to the volcano while it was erupting violently. though he managed to take a number of brilliant photographs, he co

28、uld not stay near the volcano for very long. he noticed that a river of liquid rock was coming towards him. it threatened to surround him completely, but tazieff managed to escape just in time. he waited until the volcano became quiet and he was able to return two days later. this time, he managed t

29、o climb into the mouth of kituro so that he could take photographs  and measure temperatures. tazieff has often risked his life in this way. he has been able to tell us more about active volcanoes than any man alive.    lesson68 persistent 糾纏不休 i crossed the street to avoid

30、meeting him, but he saw me and came running towards me. it was no use pretending that i had not seen him, so i waved to him. i never enjoy meeting bert dykes. he never has anything to do. no matter how busy you are, he always insists on coming with you. i had to think of a way of preventing him from

31、 following me around all morning. 'hullo, bert,' i said. 'fancy meeting you here !' 'hullo, elizabeth,' bert answered. ' i was just wondering how to spend the morning-until i saw you. you're not busy doing anything, are you ?' ' no, not at all,&

32、#39; i answered.' i'm going to. .' 'would you mind my coming with you ?' he asked, before i had finished speaking.  not at all,' i lied, 'but i'm going to the dentist.' ' then i'll come with you,' he answered.' there's always ple

33、nty to read in the 'waiting room !'   lesson69 but not murder! 并非謀殺！ i was being tested for a driving licence for the third time. i had been asked to drive in heavy traffic and had done so successfully. after having been instructed to drive out of town, i began to acquire

34、 confidence. sure that i had passed, i was almost beginning to enjoy my test. the examiner must have been pleased with my performance, for he smiled and said, 'just one more thing, mr eames. let us suppose that a child suddenly crosses the road in front of you. as soon as i tap on the window, i

35、want the car to be stopped immediately.' i continued driving and after some time, the examiner tapped loudly. though the sound could be heard clearly, it took me a long time to react. i suddenly pressed the brake pedal hard and we were both thrown forward. the examiner looked at me sadly. 'm

36、r eames,' he said, in a mournful voice,' you have just killed that child !'    lesson70  red for danger 危險(xiǎn)的紅色 during a bullfight, a drunk suddenly wandered into the middle of the ring. the crowd began to shout, but the drunk was unaware of the danger. the bull wa

37、s busy with the matador at the time, but it suddenly caught sight of the drunk who was shouting rude remarks and waving a red cap. apparently sensitive to criticism, the bull forgot all about the matador and charged at the drunk. the crowd suddenly grew quiet. the drunk, however, seemed quite sure o

38、f himself. when the bull got close to him, he clumsily stepped aside to let it pass. the crowd broke into cheers and the drunk bowed. by this time, however, three men had come into the ring and they quickly dragged the drunk to safety. even the bull seemed to feel sorry for him, for it looked on sym

39、pathetically until the drunk was out of the way before once more turning its attention to the matador.   lesson71 a famous clock 一個(gè)著名的大鐘 when you visit london, one of the first things you will see is big ben, the famous clock which can be heard all over the world on the b.b.c. if

40、 the houses of parliament had hot been burned down in 1834, the great clock would never have been erected. big ben takes its name from sir benjamin hall who was responsible for the making of the clock when the new houses of parliament were being built. it is not only of immense size, but is extremel

41、y accurate as well. officials from greenwich observatory have the clock checked twice a day. on the b.b.c. you can hear the clock when it is actually striking because microphones are connected to the clock tower. big ben has rarely gone wrong. once, however, it failed to give the correct time. a pai

42、nter who had been working on the tower hung a pot of paint on one of the hands and slowed it down !    lesson72 a car called bluebird “藍(lán)鳥”汽車 the great racing driver, sir malcolm campbell, was the first man to drive at over 300 miles per hour. he set up a new world record in septe

43、mber 1935 at bonneville salt flats, utah. bluebird, the car he was driving, had been specially built for him. it was over 30 feet in length and had a 2500 horse-power engine. although campbell reached a speed of over 304 miles per hour, he had great difficulty in controlling the car because a tyre b

44、urst during the first run. after his attempt, campbell was disappointed to learn that his average speed had been 299 miles per hour. however, a few days later, he was told that a mistake had been made. his average speed had been 301 miles per hour. since that time, racing drivers have reached speeds

45、 of over 400 miles an hour. following  his father's footsteps many years later, sir malcolm's son, donald, also set up a world record. like his father, he was driving a car called bluebird.   lesson73 the record-holder 紀(jì)錄保持者 little boys who play truant from school ar

46、e unimaginative. a quiet day's fishing, or eight hours in a cinema seeing the same film over and over again, is usually as far as they get. they have all been put to shame by a boy who, while playing truant, travelled 1600 miles. he hitch- hiked to dover and, towards evening, went into a boat to

47、 find somewhere to sleep. when he woke up next morning, he discovered that the boat had, in the1 總論1.1 項(xiàng)目概況項(xiàng)目名稱：昆明市西亮塘濕地公園游賞區(qū)建設(shè)責(zé)任單位：云南長(zhǎng)實(shí)房地產(chǎn)開發(fā)有限公司項(xiàng)目地點(diǎn)：滇池北岸官渡區(qū)西亮塘項(xiàng)目投資： 38839.82萬(wàn)元實(shí)施時(shí)間：2006年12月2008年12月1.2 項(xiàng)目提出的背景湖濱濕地作為陸地與湖泊水體之間的生態(tài)交錯(cuò)帶，是湖泊生態(tài)系統(tǒng)中的重要組成部分。湖濱濕地既是湖泊生物多樣性最豐富的場(chǎng)所，也是湖泊自凈作用有效的區(qū)域，同時(shí)也是控制污染入湖的最后一道屏障。滇池

48、流域水污染防治“十五”計(jì)劃和環(huán)滇池生態(tài)保護(hù)規(guī)劃，都將湖濱生態(tài)帶工程建設(shè)作為滇池保護(hù)與生態(tài)恢復(fù)的重要建設(shè)工程項(xiàng)目。環(huán)滇池生態(tài)保護(hù)規(guī)劃構(gòu)筑包括環(huán)湖截污、環(huán)湖道路、污水處理工程和湖濱生態(tài)帶建設(shè)在內(nèi)的水污染物排放控制體系，是未來(lái)滇池保護(hù)與生態(tài)恢復(fù)建設(shè)的重要內(nèi)容。黨中央、國(guó)務(wù)院、云南省委、省政府、昆明市委、市政府高度重視滇池污染治理工作，通過各方面多年不懈的共同努力，在滇池流域經(jīng)濟(jì)迅速增長(zhǎng)、人口增加和污染負(fù)荷不斷增大的情況下，基本遏制住了滇池水質(zhì)迅速惡化的勢(shì)頭，滇池污染治理工作取得了初步成效。然而，目前實(shí)施的低投入、低產(chǎn)出的發(fā)展和保護(hù)模式面臨著眾多的矛盾沖突，迫切需要探索環(huán)湖生態(tài)保護(hù)的新模式，加快滇池治

49、理的進(jìn)程，改善經(jīng)濟(jì)發(fā)展的外部環(huán)境，使滇池污染治理與生態(tài)保護(hù)工作邁上一個(gè)新臺(tái)階。1.3項(xiàng)目建設(shè)的必要性及意義1.3.1滇池社會(huì)經(jīng)濟(jì)概況昆明市主城區(qū)是滇池流域居民最密集，人為活動(dòng)最為活躍的區(qū)域，是全省全市經(jīng)濟(jì)、文化、商貿(mào)活動(dòng)的中心。根據(jù)第五次人口普查資料調(diào)查統(tǒng)計(jì)，流域總?cè)丝?08.4萬(wàn)人（包含居住半年以上的暫住人口）。根據(jù)2000年昆明市土地局土地利用現(xiàn)狀變更調(diào)查結(jié)果，滇池流域土地總面積為2920平方公里，其中農(nóng)用地212175公頃，占總面積的72.66；建設(shè)用地34200公頃，占11.71；未利用地45625公頃，占15.63。1.3.2 滇池北岸湖濱帶存在問題分析湖濱帶濕地是處于陸生生態(tài)系統(tǒng)與

50、水生生態(tài)系統(tǒng)之間的具有獨(dú)特的水文、土壤和植被特征的生態(tài)系統(tǒng)，它在蓄洪防旱，控制土壤侵蝕，截留和降解入湖污染物質(zhì)，改善入湖水質(zhì)，維持生物多樣性和生態(tài)平衡等方面均具有十分重要的作用。滇池近幾十年來(lái),隨著工農(nóng)業(yè)的迅猛發(fā)展,人口的大量增加和城市化不斷加快的進(jìn)程中, 對(duì)湖濱帶濕地不合理的開發(fā)利用如：圍湖造田等使湖濱帶濕地發(fā)生嚴(yán)重的退化，最終導(dǎo)致了濕地生態(tài)環(huán)境破壞、自然景觀消失、生物多樣性減少、生態(tài)系統(tǒng)結(jié)構(gòu)和功能喪失等多種生態(tài)災(zāi)難。具體表現(xiàn)在以下方面：（1）生態(tài)破壞嚴(yán)重湖濱土地過度開發(fā)、圍海造田和大規(guī)模防浪堤的修建破壞了湖濱生態(tài)環(huán)境，導(dǎo)致湖濱生態(tài)系統(tǒng)極為脆弱。從七十年代到現(xiàn)在，滇池東岸建設(shè)了很多防浪堤，能

51、被開墾為耕地或魚塘的湖濱帶均已被利用，除此外部分湖濱帶已成為永久性的旅游設(shè)施或建筑用地。這些開發(fā)活動(dòng)和防浪堤的建設(shè)嚴(yán)重破壞了滇池濕地系統(tǒng)，導(dǎo)致原有動(dòng)植物的生境的喪失，沿岸的水土流失日益嚴(yán)重，造成湖濱區(qū)水生與濕生植物由深水區(qū)、淺水區(qū)向近岸帶、陸地逐步萎縮，生物物種急劇減少，湖泊生態(tài)環(huán)境極度脆弱，湖濱區(qū)生物多樣性的衰退進(jìn)一步破壞了湖濱帶的生態(tài)功能，致使湖濱帶缺乏應(yīng)有的生態(tài)防護(hù)。除滇池西岸外，全湖大多數(shù)區(qū)域都有防浪堤，防浪堤將滇池水體與濕地系統(tǒng)隔開，破壞了原有動(dòng)植物的生境，造成湖濱區(qū)水生與濕生植物由深水區(qū)、淺水區(qū)向濕地、陸地逐步消亡。（2） 湖濱污染嚴(yán)重湖濱帶本來(lái)是湖泊攔截污染物的最后屏障，由于失去

52、天然濕地、人口密集、單位面積耕地化肥用量過大、城市點(diǎn)源截流剩余污染和城市污水處理廠工業(yè)水污染等的直接入湖等原因，使目前的滇池湖濱帶不僅喪失了凈化水質(zhì)的功能，反而還成了污染滇池水體的嚴(yán)重區(qū)域之一。（3） 面源污染嚴(yán)重滇池北岸以蔬菜和花卉生產(chǎn)為主，農(nóng)業(yè)發(fā)達(dá)，人口密度集中，面源污染是該地區(qū)的主要污染源。城市面源終極截污率僅能達(dá)到50%，農(nóng)村面源終極截污率僅能達(dá)到30%；目前農(nóng)村面污染源治理仍是缺口，對(duì)沿湖村鎮(zhèn)的生活污染沒有相關(guān)治理控制對(duì)策，農(nóng)村生活污水、絕大多數(shù)生產(chǎn)性固體有機(jī)廢棄物直接排放，最終進(jìn)入滇池水生態(tài)環(huán)境，成為滇池水體的長(zhǎng)年持續(xù)性污染源之一。1.3.3滇池濕地恢復(fù)與建設(shè)的意義（1） 湖濱濕地

53、是構(gòu)建完整湖濱生態(tài)帶的需要湖濱帶在湖泊保護(hù)中具有重要作用。湖濱帶是湖泊生態(tài)系統(tǒng)的重要組成部分，湖濱濕地在調(diào)節(jié)氣候、涵養(yǎng)水源、蓄洪抗旱、控制土壤侵蝕、凈化入湖水質(zhì)、為動(dòng)植物提供棲息和生存環(huán)境，維持生物多樣性，改善湖濱景觀，維持生態(tài)平衡等方面均具有十分重要的作用。由于濕地特殊的生態(tài)環(huán)境，決定了濕生植物具有生長(zhǎng)迅速、抗逆性強(qiáng)等特點(diǎn)，這種生物所特有的吸收和分解營(yíng)養(yǎng)物的自然過程，保證了物質(zhì)在自然生態(tài)系統(tǒng)中的有效利用，防止了物質(zhì)的過分局部積累所形成的污染。缺少完整的湖濱濕地系統(tǒng)的滇池，要有效克服富營(yíng)養(yǎng)化的局勢(shì)將是難以想象的。因此，湖濱濕地生態(tài)系統(tǒng)功能恢復(fù)與建設(shè)對(duì)于減緩滇池污染程度具有十分重要的作用和意義。

54、（2）是滇池北岸湖濱生態(tài)建設(shè)中的重要內(nèi)容在環(huán)滇池生態(tài)保護(hù)規(guī)劃和滇池流域水污染防治“十五”計(jì)劃中安排了一系列污染治理的工程措施，這些污染控制的措施是從污染源頭和污染輸送過程中減少和切斷污染源，從而達(dá)到控制污染的目的，強(qiáng)調(diào)的是“治”。而湖濱帶生態(tài)恢復(fù)與濕地建設(shè)作為流域生態(tài)修復(fù)類的重要項(xiàng)目被定為特優(yōu)先項(xiàng)目，該項(xiàng)目將在滇池沿岸筑起一道保護(hù)屏障，修復(fù)滇池湖濱帶生態(tài)系統(tǒng)，強(qiáng)調(diào)的是“防”。尤其是湖濱生態(tài)工程建設(shè)與環(huán)湖截污污水處理構(gòu)成完整的污染控制體系，成為了滇池污染防治工程的重要支撐。表3-1滇池北岸（含主城區(qū)）湖濱帶建設(shè)項(xiàng)目匯總表序號(hào)工程名稱工程規(guī)模實(shí)施年限1人工濕地建設(shè)人工濕地布水系統(tǒng)建設(shè)，建12.7k

55、m2（19050畝）人工濕地200520082天然濕地生態(tài)建設(shè)1887.4m等高線潮水漲落帶內(nèi)，建5.6km2（8400畝）天然濕地200520083防護(hù)林區(qū)生態(tài)建設(shè)在濕地外圍因地制宜1km2（1500畝）防護(hù)林帶20052008（3） 項(xiàng)目的建設(shè)是北岸片區(qū)可持續(xù)發(fā)展的需要項(xiàng)目區(qū)生態(tài)環(huán)境存在以下主要問題：土地墾殖率高，大棚蔬菜、花卉產(chǎn)業(yè)發(fā)展迅速，農(nóng)村固體廢棄物數(shù)量巨大，面源污染十分嚴(yán)重；湖濱自然生態(tài)破壞嚴(yán)重，土地開墾過度，天然濕地幾乎已消失殆盡；區(qū)域內(nèi)人口和建設(shè)用地發(fā)展速度不斷加快，人地矛盾、生存與環(huán)境保護(hù)的矛盾十分突出；目前尚缺乏污染控制設(shè)施，點(diǎn)源和面源污染均沒有得到有效控制，給區(qū)內(nèi)水環(huán)境和

56、滇池的水環(huán)境保護(hù)帶來(lái)嚴(yán)重的影響，隨著片區(qū)經(jīng)濟(jì)的發(fā)展，這一影響將更加突出。為了保障片區(qū)經(jīng)濟(jì)的可持續(xù)發(fā)展，完全有必要改變現(xiàn)有的農(nóng)業(yè)生產(chǎn)模式，變農(nóng)業(yè)生產(chǎn)為濕地生產(chǎn)，通過濕地建設(shè)營(yíng)造人與自然間的和諧環(huán)境，從而提升區(qū)域土地利用價(jià)值，同時(shí)最大限度地減少片區(qū)農(nóng)業(yè)生產(chǎn)廢物及農(nóng)藥、化肥污染，實(shí)現(xiàn)片區(qū)經(jīng)濟(jì)可持續(xù)發(fā)展。（4） 項(xiàng)目的建設(shè)是環(huán)境與經(jīng)濟(jì)協(xié)調(diào)發(fā)展的需求本項(xiàng)目的建設(shè)突出湖濱帶的環(huán)境效益，充分發(fā)揮人工濕地對(duì)污染物的凈化作用，將滇池湖濱帶建設(shè)納入流域污染控制系統(tǒng)整體規(guī)劃和設(shè)計(jì)中，在滇池流域系統(tǒng)的點(diǎn)源和面源污染治理基礎(chǔ)上，恢復(fù)湖濱生態(tài)系統(tǒng)的結(jié)構(gòu)與功能特征，使建成的湖濱帶成為地表水污染物進(jìn)入滇池的最后一道屏障，最大

57、程度截流污染物，并形成一個(gè)具有一定的抵御和調(diào)節(jié)自然和人類活動(dòng)干擾的能力的、能自我維持和調(diào)節(jié)的生態(tài)系統(tǒng)，同時(shí)使之與周圍的系統(tǒng)與景觀融為一體。兼顧湖濱帶的景觀功能與經(jīng)濟(jì)價(jià)值，通過湖濱帶建設(shè)提升沿湖土地價(jià)值，以環(huán)境改善來(lái)促進(jìn)流域經(jīng)濟(jì)發(fā)展，為昆明市、環(huán)滇池生態(tài)圈的可持續(xù)發(fā)展奠定了堅(jiān)實(shí)基礎(chǔ)，創(chuàng)造了良好條件。因此本項(xiàng)目建設(shè)十分必要，是實(shí)現(xiàn)片區(qū)經(jīng)濟(jì)社會(huì)發(fā)展與環(huán)境保護(hù)雙贏的重要舉措。1.4 完成本項(xiàng)目所具備的條件1.4.1本項(xiàng)目的理論依據(jù)和技術(shù)支撐在湖濱生態(tài)系統(tǒng)中，水禽處于水生生態(tài)系統(tǒng)食物鏈中的最高生態(tài)位，而魚蝦產(chǎn)卵、生產(chǎn)孵化的數(shù)量和沉水植物密切相關(guān)，隨著湖泊濕地遭到破壞，魚蝦產(chǎn)量勢(shì)必下降，水禽的數(shù)量就會(huì)因失

58、去食物來(lái)源而萎縮，直至完全消失。隨著湖泊濕地恢復(fù)，魚蝦產(chǎn)量會(huì)逐步恢復(fù)，水禽的數(shù)量也將逐步增加。因此湖濱濕地在湖泊生態(tài)系統(tǒng)中占據(jù)著非常重要的地位。濕地與森林、農(nóng)田等生態(tài)環(huán)境一樣，廣泛分布于世界各地，是地球上最富生物多樣性的生態(tài)景觀、生產(chǎn)力較高和人類最重要的生存環(huán)境之一。在生態(tài)系統(tǒng)中，濕地處于陸生生態(tài)系統(tǒng)和水生生態(tài)系統(tǒng)的交界，濕地生態(tài)結(jié)構(gòu)和功能的好壞可能對(duì)陸地生態(tài)系統(tǒng)沒有太大的影響，但對(duì)水生生態(tài)系統(tǒng)將產(chǎn)生難以預(yù)料的后果。它對(duì)一個(gè)國(guó)家乃至全球的經(jīng)濟(jì)發(fā)展和人類生存環(huán)境都具有重要的影響，因此被喻為“地球的腎”。因此，對(duì)濕地的恢復(fù)、保護(hù)與持續(xù)利用已成為國(guó)際社會(huì)關(guān)注的熱點(diǎn)。濕地在生態(tài)系統(tǒng)中具有以下的主要功能

59、：（1） 滯留營(yíng)養(yǎng)物營(yíng)養(yǎng)物質(zhì)經(jīng)徑流被帶到濕地中，隨沉積物沉降之后，通過濕地生物吸收，經(jīng)化學(xué)和生物學(xué)過程轉(zhuǎn)換而被儲(chǔ)存起來(lái)，最終通過對(duì)濕地生物的收獲而將營(yíng)養(yǎng)物質(zhì)帶出系統(tǒng)外；（2） 防止自然力的破壞濕地植被的自然特性可防止或減輕對(duì)海岸線、河口灣和江河岸的侵蝕；達(dá)到保護(hù)海岸線及控制侵蝕、防風(fēng)和排除有毒物的作用；（3） 流量調(diào)節(jié)濕地能儲(chǔ)存可能來(lái)自降水、徑流或地下水源的過量水分，減緩水流，避免下游地域洪水的泛濫；（4）滯留沉積濕地特別是沼澤地和泛洪平原的自然屬性(如植被、面積大小、水深等)有助于減緩水流的速度，有利于沉積物的沉降和排除；（5） 保護(hù)自然界生物多樣性由于濕地系統(tǒng)的存在，為各種水生生物提供了優(yōu)

60、良的生活和繁衍環(huán)境條件，使得濕地中的生物種類和數(shù)量不斷增加。1.4.2本項(xiàng)目已有的工作基礎(chǔ)和應(yīng)用效果（1） 貴州威寧的草海濕地我國(guó)在濕地生態(tài)恢復(fù)方面最為成功的例子是貴州威寧的草海。為了擴(kuò)大耕地面積，1970年曾排水疏干草海，湖中的魚類、貝類、蝦和水生昆蟲等幾乎絕滅，所剩水禽也寥寥無(wú)幾，地下水位下降，農(nóng)業(yè)減產(chǎn)，自然生態(tài)失去平衡。1980年政府決定恢復(fù)草海，實(shí)施蓄水工程，恢復(fù)水面面積20km2，平水期可達(dá)29km2。目前，生物物種已得到恢復(fù)，浮游植物有8門91屬;高等植物20科26屬37種，組成了多種挺水植物群落、浮葉植物群落和沉水植物群落。浮游動(dòng)物有9綱74屬115種；魚類9種；兩棲類14種，特

61、別是鳥類豐富，有179種，其中水禽有68種。黑頸鶴、白頭鶴、白鶴、灰鶴、游隼、自琵鷺等16種國(guó)家一、二級(jí)保護(hù)鳥類的數(shù)量日漸增多，濕地恢復(fù)效果良好，被國(guó)外專家視為中國(guó)濕地生態(tài)恢復(fù)的成功典范。該濕地作為我國(guó)特有物種黑頸鶴的主要越冬棲息地，目前已被建立為國(guó)家級(jí)自然保護(hù)區(qū)。（2） 滇池湖濱人工濕地建設(shè)2004年6月建成運(yùn)行的大清河復(fù)合人生態(tài)工濕地示范工程，占地面積約20畝，采用復(fù)合污水工程預(yù)處理加人工濕地處理的工藝，進(jìn)水取自典型合流制城市污水的海河水，正常運(yùn)行日處理水量為2000m3，水力停留時(shí)間約5天，監(jiān)測(cè)結(jié)果表明，該復(fù)合人工濕地出水中的主要富營(yíng)養(yǎng)化指標(biāo)均優(yōu)于國(guó)標(biāo)城鎮(zhèn)污水處理廠污染物排放標(biāo)準(zhǔn)一級(jí)a標(biāo)準(zhǔn)，環(huán)境效益十分顯著：對(duì)進(jìn)水水體中的總氮、總磷及懸浮物平均去除率分