B1 Unit 4 Text 1 英汉对照.doc

8英语泛读教程1-Unit Four-Text 1英汉对照Text OneMigratory Birds and CoffeeIntroduction-Shade-grow coffee plantations play a key role in the conservation of migratory birds that have found a sanctuary in he forest-like environment. Read the following fact sheet and learn more about it. 1 In both North and Latin America, migratory birds have found a sanctuary in the forest-like environment of traditional coffee plantations. In eastern Chiapas, Mexico, biologists found that traditionally-managed coffee and cacao (chocolate) plantations support over 150 species of birds; a greater number is found in other agricultural habitats, and exceeded only in undisturbed tropical forest. Even in very disturbed areas, coffee plantations support good populations of migrants and other species that prefer or are restricted to forest habitats, such as redstarts, black-throated green warblers , and residents including parrots and woodcreepers. 2 However, because of recent changes in coffee production and marketing, shade coffee plantations are a threatened habitat. In the past twenty years, coffee has begun to be grown with no shade canopy at all. While this manner of cultivation produces increased yields, these cannot be sustained for many years without intensive management (additions of chemical fertilizers and a range of insecticides, herbicides and fungicides). 3 Aside from the agronomic risks, sun coffee production has resulted in major habitat change for migratory birds in the past two decades. Of the permanent cropland planted in coffee, the amount under modern, reduced-shade coffee systems ranges from 17% in Mexico to 40% in Costa Rica and 69% in Colombia. The few studies that have been conducted have found that the diversity of migratory birds drops sharply when coffee is converted from shade to sun. One study found a decrease from 10 to 4 common species of migratory birds. As for the overall avifauna, studies in Colombia and Mexico found 94-97% fewer bird species in sun grown coffee than in shade grown coffee. This comes as no surprise since over two-thirds of the birds are found in the canopy of shade plantations and less than 10% are found in coffee plants.4 Of all agricultural systems in the tropics, shade coffee plantations have been found to have some of the highest numbers of individuals and species of migratory birds: Chan Robbins and Alejandro Estrada, leading a team of bird surveyors around Mexico and the Caribbean Basin, found that cacao and coffee plantations supported the largest numbers of forest-dependent migratory birds of any agricultural habitats. 5 In Where Have All the Birds Gone?, tropical ecologist John Terborgh writes “Some agricultural practices are compatible with the maintenance of high populations of migrants. He concluded that coffee and cacao make good migrant habitat although some forest specialist species, particularly residents, may be missing. 6 Grown in the time-honored manner, coffee bushes are cultivated under a forest overstory. Coffee is also commonly grown using indigenous agroforestry techniques, originally developed for growing cacao. This involves planting a mixture of nitrogen-fixing trees with other useful species to provide shade. Up to 40 species of trees can be found in some traditionally managed plantations, and many of these are managed for household or commercial commodities such as wood or fruit. 7 Shade trees protect the understory coffee plants from rain and sun, help maintain soil quality, reduce the need for weeding, and aid in pest control. Organic matter from the shade trees also provides a natural mulch, which reduces the need for chemical fertilizers, reduces erosion, contributes important nutrients to the soil, and prevents metal toxicities. 8 Traditional coffee plantations can be thought of as modified forest habitats. Even where a single species of tree is planted as cover, the trees often produce flower and fruit crops used by omnivorous birds, such as Tennessee warblers and orchard orioles. Evidence suggests that up-mountain and northward movements are timed to take advantage of the blossoming of plantation trees. 9 In the regions most heavily used by migratory birdsMesoamerica, the Caribbean islands,and Colombiacoffee plantation forests cover 2.7 million hectares, or almost half of the permanent cropland. In southern Mexico, coffee plantations cover an area over half the size of all of the major moist tropical forest reserves, providing critical woodland habitat in mid-elevation areas where virtually no large reserves are found. 10 Birds are only one indicator of the role that coffee plays in protecting biological diversity. Ongoing studies of insects, canopy trees, orchids, and amphibians show that coffee plantations are often critical refuges protecting forest species where there is no longer any forest. In Costa Rica, insect diversity in shaded coffee rivals that found in lowland rain forest areas. 11 Shade coffee presents a tremendous opportunity for both conservation and economic gain, in that such a relatively benign form of agriculture has been and continues to be so significant an economic engine for the Latin American and Caribbean region. 12 Although coffee originated in the Old World, over 2/3 of the current world production is exported from Latin America and the Caribbean. It is primarily grown by families on small farms. Coffee is the third most common import in the U.S., behind oil and steel, respectively. The U.S. consumes about 1/3 of the worlds coffee. 13 In dollar value, coffee is second only to petroleum as the most important legal export commodity in the world. Revenues exceed 10 billion dollars per year. It is the second largest source of foreign exchange for developing countries around the world and is particularly important for Latin America and the Caribbean, where it is the leading source of foreign exchange. 14 Productive sun coffee cultivation requires chemical inputs and year-round labor, placing financial demands and the need for credits on the growers. Consequently, most technification of coffee growing (conversion to sun plantations) is done by larger land-holders. 15 While technified coffee may signify benefits to producers in terms of total crop outputa condition which may not hold true over the long run, and already proven false in some areas where sun coffee is being grownthe relentless push of agribusiness to produce more coffee per unit area may have serious environmental and social ramifications. 16 Conversion to sun coffee appears to lead to greater soil erosion, acidification, and higher amounts of toxic run-off. In addition, conversion to sun coffee results in a loss of trees, which both provide insurance crops to the grower (e.g. fuel wood, timber, citrus, and other fruit trees planted in the canopy), and help maintain local and micro-climatic conditions. 17 Increasingly, the relationship between sound agriculture, the long-term health of rural farmers, and maintenance of biological diversity is more obvious. Because of its high profitability per unit area compared to raising corn or beef, coffee growing had been seen as a way for small landowners to obtain cash with relatively little investment. Traditional coffee farming reduces the farmers dependence on expensive chemical applications, safeguarding growers and their families from the possible harmful effects of contact with pesticides. 18 However, the reliance on a single export commodity by farmers in many countries often ends in overproduction. and the trend towards free market economics has caused a crisis in coffee production. countries such as Colombia have taken deliberate steps to modernize production, driving small and inefficient growers into alternative land uses. With a simultaneous reduction in access to agricultural credits, many farmers struggle to make ends meet and some have been forced to alter their coffee plantations by removing canopy trees for fire-wood or abandoning coffee as their cash crop altogether. 19 The conservation of migratory birds depends on conservation of habitats, but parks and reserves alone will not provide adequate space for protection. The fate of migratory birds and other wide-ranging species depends upon the quality of human-managed habitats. The health of temperate and tropical ecosystems is bound together by the migration of billions of birds each yearand shaded coffee plantations play a key role. 20 This form of land use may itself be on the way to becoming an endangered species. Ponder this over your next cup of coffee: Would you be willing to pay more for coffee if you knew the extra money would be used for extension services and affordable credit for coffee farmers to survive and grow coffee in a more bird-friendly manner? 课文一Migratory Birds and Coffee 导语：侯鸟在类似森林环境的荫栽咖啡种植园找到了栖息地，这些种植园在保护候鸟方面起了重要作用。阅读下面的介绍，以了解更多这方面的信息。 1. 在北美洲和拉丁美洲，候鸟在传统咖啡种植园类似森林的环境中找到栖息地。生物学家发现，在东恰帕斯和墨西哥，传统方式经营的咖啡和可可(巧克力)种植园支持的鸟类超过150种。在其他农业栖息地，发现的鸟类数目更大，末受侵扰的热带森林才会超过这个数目。即使在受到较大侵扰的地区，咖啡种植园也支持为数可观的候鸟和其他鸟类。这些候鸟和其他鸟类，如红尾鸟和黑喉绿莺，以及包括鹦鹉和砍林鸟在内的居民，选择了森林栖息地，或者仅限于森林栖息地。 2. 然而，由于近来咖啡生产和营销方面的变化，荫栽咖啡种植园成了受到威胁的栖息地。过去的20年里，开始不用任何荫遮来种植咖啡。这样的种植方式提高了产量，同时，如果没有精心管理(增加化肥和一定范围的除虫剂、除草剂和杀菌剂)，就不能持续多年高产。 3. 除了农林方面的风险，日照咖啡生产导致过去20年候鸟主要栖息地的变化。在种植咖啡的永久性作物区，现代的，减少荫栽咖啡的系统，其总量在墨西哥为17，在哥斯达黎力口为40，在哥伦比亚为69。已经进行的为数不多的研究发现，当咖啡由遮荫变为日照，候鸟种类就急剧下降。有一个研究发现，常见候鸟种类从10减少到4。在哥伦比亚和墨西哥的研究表明，区域鸟类总数在日照咖啡种植区比荫栽咖啡种植区要少94-97。这样的数据并不令人吃惊，因为人们发现，树阴覆盖的种植园可以看到的鸟类超过三分之二，而在日照咖啡树丛里，鸟的种类不到十分之一。 4. 人们发现，在热带所有农业系统中，荫栽咖啡种植园有一些数量较多的个体和候鸟种类。尚罗宾斯和亚历杭德罗埃斯特拉达率领一组鸟类调查人员活动在墨西哥和加勒比盆地附近。他们发现，可可和咖啡种植园支持农业栖息地的森林依赖性候鸟数量最大5. 热带生态学家约翰特博在鸟儿飞到哪里去了?中写道， ”有些农业实践同保持众多数量的迁徙者是并行不悖的。”他得出结论，尽管有些森林的特有物种，特别是居民，也许正在消失，”咖啡和可可园构成了不错的迁徙栖息地。” 6. 用传统方式培植的咖啡树丛，在森林植被顶层覆盖之下，通常也采用原来种植可可而发展起来的农林技术栽培，用种植树木和其他有用植物，来增加遮荫。在一些传统方式耕作的种植园，可以找到的树木种类多达40种，其中有许多是为家庭或木材与水果类商品而种植。 7. 遮荫树木保护地被层的咖啡植株不受雨水和日照侵害，有助于土质的保持，减少对除草的需要，帮助控制害虫。来自遮荫树木的有机物质，也提供了自然的表土覆盖物，减少了对化肥的需要，减少侵蚀，为土壤提供重要养料，防止金属有毒物质。 8. 可以将传统的咖啡种植园看成经过改造的森林栖息地。有证据显示，向山区和向北移动是依时而行，为的是利用种植园树木的花期。9. 在候鸟聚居最多的地区中美洲，加勒比岛屿，哥伦比亚咖啡种植园”森林”占地270万公顷，几乎是永久种植区面积的一半。在南墨西哥，咖啡种植园覆盖的地区已超过主要湿地热带森林保护区总面积的一半，为实际上没有大面积保护区的地方提供重要的林地栖息地。 10. 鸟类只是咖啡在保护生物多样化方面所起作用的一个指示生物群落而已。正在进行的对昆虫、遮荫树木、兰科植物和两栖动物的研究表明，在不再