中国生态文明建设（中英对照）连载之八
生态系统退化
本书由北京语言大学出版社出版，2014（教学课件光盘版） 作者 蒋高明
2.1.3生态系统相继退化
2.1.3 Gradual ecosystem degradation
不合理的发展方式，除了对环境造成严重的污染，还对各类自然生态系统造成了结构性的破坏，最终导致生态系统功能退化。目前，中国十大陆地生态系统都处在不同程度的退化过程中。除了众所周知的森林锐减、荒漠化扩大外，连高寒草甸、温带草原和红树林等生态系统，也受到了严重威胁。
An irrational growth mode does not only cause serious pollution to the environment, but also results in structural damages to various types of natural ecosystems, eventually leading to the degradation of their functions. At present, China’s top 10 terrestrial ecosystems are at different levels of degradation. In addition to the acknowledged sharp decline of forests and expansion of desertification, other ecosystems like the alpine meadows, temperate grasslands and mangrove ecosystems are all facing grave threats.
青藏高原分布的高寒草甸生态系统，因海拔最高、面积最大而闻名世界。因为人烟稀少，过去很少发生生态退化。而如今，这里生态退化非常严重，总体生产力极度下降。20世纪60年代，这里平均每亩干草产量是300公斤，如今降到100公斤以下，50年内减少了2/3以上。高寒草甸的初级生产力[1]本来就很低，产草量严重下降，意味着生态过程的基础被削弱，生态结构受损，这样下去连下面的冻土都难以保持。
The alpine meadow ecosystem on the Qinghai-Tibet Plateau is well known for its highest elevation and largest coverage. In the past, ecological degradation rarely occurred due to the sparse population there. But now, severe ecological degradation is causing sharp decrease in overall productivity. In the 1960s, the average hay yield was 300 kg/mu (1 hector =15 mu), whereas now it is less than 100 kg/mu, a 2/3 decrease over 50 years. The primary productivity of the alpine meadow is undoubtedly low, and with the sharp drop of forage yield, the foundation for ecological processes has been weakened and the ecological structure damaged. Eventually the underground tjaele will not be maintained.
草原的现状也不容乐观。占据国土面积41%的各类草原，竟然出现了90%的不同程度的退化，并且退化面积正以每年200万公顷的速度递增。在退化草原中，有55%被开垦为耕地，30%沦为不可利用土地。有人认为草原退化的原因在于干旱的气候和蝗灾、鼠害等“天灾”，但实际上，超载放牧对草原的破坏更大。新疆、宁夏、内蒙超载率分别达121%、72%和66%。超载放牧破坏草原植被的同时，还压制了草原生态的自然恢复。
The status quo of grasslands is not desirable, either. A total of 90% of various grasslands occupying 41% of the national land area show varying degrees of degradation, and the degradation is expanding at an annual rate of 2 million hectares. Among them, 55% are reclaimed farmlands, and 30% become worthless. Some people pin the blame for degradation on an arid climate and natural infestations like locusts and rats, but in fact, overgrazing is more destructive to grasslands. The overgrazing rates of Xinjiang, Ningxia, and Inner Mongolia are 121%, 72% and 66% respectively. Overgrazing not only causes damage to grassland vegetation, but also hinders natural rejuvenation of grasslands.
红树林是世界公认的生产力高、生物多样性丰富的生态系统之一。中国的红树林主要分布在福建沿岸以南，历史上最大面积曾达25万公顷。近30年来，由于受到掠夺性砍伐和违背科学的低效能利用，目前沿海红树林资源正在消失。20世纪50年代，红树林约剩下5万公顷，现在仅剩1.5万公顷。红树林为什么消失得那么快？因为它们分布的地区正是沿海经济发达地区，可以说是“寸土寸金”。经济开发需要土地，红树林成为各类楼盘、商场、工厂或道路的牺牲品。但是，没有了红树林的呵护，沿海的城市或别墅，就没有了安全保障，成为了海潮袭击的对象。2004年，印尼海啸夺走了23万人的生命，城市遭到了毁灭，但相距不远，有红树林保护的村庄却安然无恙。
Mangrove is universally acknowledged as the world’s ecosystem of high productivity and rich biodiversity. China’s mangroves are located mainly to the south of Fujian, and their largest known coverage area in history was 250,000 hectares. During the past 30 years, due to deforestation and unscientific and inefficient utilization, the coastal mangrove resources have been disappearing. In the 1950s, there were 50,000 hectares of mangroves left; now there are only 15,000 hectares. Why have the mangroves disappeared so fast? Because they lie in economically developed coastal areas, and the cost of land in these areas is very high. Economic development calls for land, so mangroves have become the victims of real estate, shopping malls, factories or roads. However, without mangroves, coastal cities or villas are stripped of their protection, thus becoming objects of tidal attack. The Indonesian Tsunami in 2004 took the lives of 230,000 people away. It was found out that some cities were destroyed but the nearby villages remained unharmed because of the protection of mangroves.
生物失去的不仅仅是家园，一些物种连“香火”都快要断送了。联合国《国际濒危物种贸易公约》列出的740种世界性濒危物种中，中国占189种，约为总数的25%。中国濒危或接近濒危高等植物达4000～5000种，占全国高等植物总数的15%～20%。环境污染、大坝建设、毁林开荒、生境破碎化[2]是造成生物多样性减少的重要原因。如今，长江白鳍豚，按照专家的说法已经功能性灭绝，实际上，这个物种在野外已经没有了，物种已经失去了自行繁衍生存的条件。
For some species, degradation means not merely the loss of their homes but also the loss of conditions for their existence. Among 740 kinds of endangered species listed by the Convention on International Trade in Endangered Species of Wild Fauna and Flora, 189, or about 25%, come from China. China’s endangered or near-endangered higher plants amount to 4,000 to 5,000 kinds, accounting for 15% to 20% of the total higher plants in the country. Environmental pollution, dam construction, and damage to forests caused by land reclamation, habitat fragmentation, contribute heavily to the loss of biodiversity. Today, the white-flag dolphin in the Yangtze River, according to experts, has become functionally extinct. In fact, this species is not to be found in the wild and it has lost the condition to reproduce by itself.
[1] 初级生产力：指生态系统中植物或其他生物进行光合作用、制造有机物的生产力，次级生产力则指动物等生态系统中的消费者消化食物，转化为自身的组织、能量的过程。可参考第一章第一节的开头。
[1] Primary productivity refers to the production of organic matters by plants and other living organisms through the process of photosynthesis; secondary productivity refers to the generation of tissues and energy in consumers in an ecosystem such as animals by themselves through the consumption of food. Details refer to the beginning part of the first section of the first chapter.
[2] 生境破碎化：指物种的野外生存环境被压缩、被分割。物种繁衍需要足够大的生存环境，生存环境缩小或者被分割，会严重影响物种的正常繁衍生存。
[2] Habitat fragmentation: refers to the emergence of discontinuities (fragmentation) in an organism’s preferred environment (habitat). An organism needs an environment large enough to survive and multiply, but the discontinuities and fragmentation of the environment will seriously affect the survival of many species.
