小時(shí)候，我生活的城市自然環(huán)境和基礎(chǔ)設(shè)施都比較差。城市周圍是延綿不斷的黃土荒山，除了兩個(gè)公園和一些機(jī)關(guān)學(xué)校外，城市其他地方幾乎沒(méi)有樹木。不過(guò)城里還有不少充滿自然氣息的地方。黃河穿城而過(guò)，岸邊灘涂延綿不斷；山前地帶有不少水塘；城市幾個(gè)組團(tuán)之間是大片的瓜田菜地，除了建筑和道路外，城里的其他土地大多沒(méi)有被硬化。城市生活雖清貧單調(diào)，但也很安逸。孩子們更是快樂(lè)，晴日看著藍(lán)天白云，大雁南飛北上，雄鷹盤旋，蜂飛蝶舞，燕子低飛，夜晚數(shù)著滿天星斗，伴著蟲鳴蛙聲，聽大人們講野狼豺狐的故事。至于逮蛐蛐捉螞蚱爬樹捉鳥粘蜻蜓抓蝴蝶，則是孩子們樂(lè)此不疲的與自然互動(dòng)的游戲，伴隨了每個(gè)人的童年。

現(xiàn)在，我的故鄉(xiāng)已煥然一新，幾乎找不到過(guò)去的影子。城中高樓林立，路網(wǎng)縱橫，道路兩側(cè)有了行道樹，周圍的荒山變綠了，原來(lái)的灘涂、水坑、瓜田和菜地大多已消失，變成了道路和高樓，少數(shù)留下來(lái)的田野灘涂被改造為人工氣息濃厚的公園綠地，種植了許多原來(lái)城市中根本沒(méi)有的花草樹木種類。城市富裕了、繁華了，但隨之而來(lái)的是擁堵的交通、污濁的空氣和頻繁發(fā)生的水土流失與滑坡。除了家養(yǎng)的鴿子和偶見(jiàn)的麻雀，城市里很少見(jiàn)到鳥兒，草地里除了螞蟻，也少有別的昆蟲，不僅雄鷹大雁已成往事，連蟋蟀螞蚱都成了稀有，城市里最常見(jiàn)的動(dòng)物只剩下寵物貓和寵物狗。

我所提到的城市在中國(guó)絕不是一個(gè)孤例。20年間，幾乎所有的城市都經(jīng)歷了同樣的變化。城市在不斷拓展的同時(shí)摧毀了大地上曾經(jīng)豐富多彩的田野、湖澤、森林，在這些土地上生活的多樣的生物也隨之消失。

我們知道，地球表層是由動(dòng)物、植物、微生物等所有生物和它們賴以生存的環(huán)境組成的一個(gè)巨大的生物圈，人類只是其中一員。但自從人類出現(xiàn)以后，尤其是工業(yè)革命以來(lái)，世界人口不斷增加，對(duì)生活資料的需要越來(lái)越多，對(duì)自然資源的攫取越來(lái)越?jīng)]有限度，人類的活動(dòng)范圍不斷擴(kuò)大，對(duì)自然環(huán)境的干擾也越來(lái)越多，其它生物的生存空間不斷縮小，并且被人類的活動(dòng)割裂得支離破碎，生物的種群數(shù)量急劇減少，大量物種面臨滅絕的危險(xiǎn)。有科學(xué)家認(rèn)為，如果物種以目前的速度減少下去，到2050年，四分之一到一半的物種將會(huì)滅絕或?yàn)l臨滅絕。我們正在經(jīng)歷地球歷史上的第6次物種大滅絕。與前幾次自然因素主導(dǎo)的不同，這一次，人類成為罪魁禍?zhǔn)住?/p>

自然環(huán)境的退化，使生物失去了進(jìn)化所需要的環(huán)境和條件，物種在不斷消亡，卻很難有新的物種產(chǎn)生。大量的物種銷聲匿跡，它們?cè)谏鷳B(tài)系統(tǒng)中承載的功能也消失了，生態(tài)系統(tǒng)的平衡被打破，系統(tǒng)變得非常脆弱，易于崩潰。如果這一趨勢(shì)不能得到扭轉(zhuǎn)的話，最終將威脅到人類自身的生存，也許我們自己將成為下一個(gè)滅絕的物種。

因此，對(duì)于生物多樣性的保護(hù)是一件非常急迫的任務(wù)。我們不僅要保護(hù)重要的生物棲息地，建立自然保護(hù)區(qū)和國(guó)家公園，而且要在人類的生活環(huán)境中為其它生物留出生活的空間和遷徙的通道，讓它們?cè)诘厍蛏系臈⒌啬軌蛐纬删W(wǎng)絡(luò)，保證物種的延續(xù)和進(jìn)化。人類建造的城市再也不能成為粗暴割裂生物棲息環(huán)境的鋼筋混凝土荒漠，而是要成為生態(tài)網(wǎng)絡(luò)上的一個(gè)節(jié)點(diǎn)，在這里人類的文化系統(tǒng)與自然的生態(tài)系統(tǒng)能夠有機(jī)融合，達(dá)到一種平衡。這就要求我們?cè)诔鞘薪ㄔO(shè)過(guò)程中尊重原有的地形、地貌、水文、植被等自然條件，研究并保留原有的動(dòng)植物棲息環(huán)境，并在此基礎(chǔ)上形成網(wǎng)絡(luò)狀的景觀系統(tǒng)；以鄉(xiāng)土植被群落為藍(lán)本選擇城市植物，多保留一些自然群落，發(fā)揮自然的能動(dòng)性，構(gòu)成真正適合動(dòng)物棲息的環(huán)境；治理河流污染，恢復(fù)河流的自然駁岸，為水生動(dòng)物、兩棲動(dòng)物和鳥類提供棲息地；綠化城市屋頂，為昆蟲和鳥類提供可以生活或停留的“空中草原”……這樣的城市不僅能滿足人類的生活、休閑、審美和獲得教育的需要，而且為動(dòng)物提供了適宜的食物、充足的水源、安全的棲息環(huán)境和遷徙的通道，城市的生態(tài)環(huán)境也會(huì)有很大的改善，人類的生活也會(huì)更加健康和幸福。

中國(guó)現(xiàn)在的城市面臨巨大的人口壓力和嚴(yán)峻的環(huán)境問(wèn)題，以往的城市規(guī)劃和建設(shè)模式已經(jīng)讓每個(gè)人都品嘗到了苦果。找到一種環(huán)境和經(jīng)濟(jì)雙贏的城市發(fā)展方式是我們的當(dāng)務(wù)之急。在這個(gè)歷史過(guò)程中，風(fēng)景園林將扮演什么樣的角色呢？

PREFACE

Back when I was a child, the city I lived in was poor in natural environment and urban infrastructure. City was surrounded by waves of barren mountains; and there were barely trees except for those in the two parks and some Institutions and schools. However,some natural elements were fortunately gratifying in many places: the Yellow River ran across the city and brought beautiful river shoals alongside the river; plentiful ponds could be found in piedmont, and vegetable farms in between groups in city; lands were merely hardened on roads and buildings. Poor and simple, life was easy and comfortable enough, especially for kids. Interactions with nature were fascinating: wild gooses and eagles could be found now and again in the blue sky; bees and butterflies came and stayed among flowers; nights were filled with shining stars and chorus of frogs and insects… Those were the memories that had planted in everyone's childhood.

Today, my hometown has changed beyond recognition. The city are now filled with clusters of high-rise buildings and complicated road network; street trees are planted and waste mountains has been afforested; river shoals and farms are replaced by roads and buildings, leaving only a few shoals being transformed into an artificial park green space with lots of plant species which are new to the city. Rich and prosperous, life has become difficult and troublesome. Instead of birds and blue skies, what people often meet are traffic jams, polluted air, and frequent incidents of landslide, water loss and soil erosion. Wild gooses and eagles no longer fly in the sky, bees or crickets are nowhere to be found; what's left in the city are pet dogs and cats.

Sadly, this is not the only case in China. In the past 20 years, almost every city in China experienced the same transformation.Cities have been expanding at the cost of the destruction of natural fields, lakes and forest and the extinction of the diverse creatures that live in it.

Let us remind that the epigeosphere is a giant biosphere made up by all living creatures such as animals, plants and microorganism and the environment they survive in, and human beings are only one of them. However, since the existence of human being, especially since the industry revolution, the global population has expanded greatly and therefore the needs for means of livelihood. As the take-out from natural resources becomes limitless and the range of human activity expands, the interruption caused to the nature has increased sharply, resulting in the huge shrink and fragmentation of the living space and the sharp decline in the population quantity of other living creatures. If such decline cannot be controlled in time, according to the scientists, about 1/4 to 1/2 of the species will die out or be endangered by 2050. We are experiencing the 6thmass extinction in earth history, but only that this time the leading cause is not from the nature, but ourselves.

The degradation of nature also takes away the conditions and environment for the evolution of species. The mass extinction of the existing species and the absent of new species have destroyed the balance of the ecological system, leaving it vulnerable and being on the verge of collapse. If such trend cannot be turned over, we human beings may very likely be the next extinct species.

Therefore, it is an urgent and critical mission to protect biodiversity on earth. Protecting wildlife habitats for and creating nature reserves and national parks are not enough; we must also spare sufficient living and migration space in human's living environment for other species, allowing their habitats to form a network and assuring the survival and evolution of their tribes. Cities have to become connections in the ecological network where human culture and ecosystem can be integrated and balanced. To do so, we must, in the process of urban construction, respect for natural conditions such as landforms, hydrology and vegetation, study and preserve existing habitats for animals and plants; and, on this basis, create a landscape system network; select urban plants according to native vegetation community, retain natural communities as many as possible in order to create environment suitable for animals to live in; control river pollutions and recover waterfront revetment to provide habitat for aquatic animals, amphibian and birds; develop urban green roofs to create "sky grasslands" for insects and birds to live or to stay… Such cities not only fulfill the needs of human's life, recreation,aesthetics and education, but also provide sufficient foods and waters, safe habitats and migrant space for animals. In this way, the ecological environment in city will be largely improved, and therefore our life will be happier and healthier.

Cities in China are facing enormous pressure from population and environmental issues. The old urban planning and construction pattern has brought us a bitter end. Finding a development pattern mutually beneficial for the environment and economy is our top priority. In this process of history, what roles should landscape architecture plays?