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第一段
1 .Listen to a part of a lecture in a conservation biology class.
听一段在保护生物课程中的演讲
第二段
1 .One consequence of global warming is extinction, there is compelling evidence that global warming will be a significant driver of many plant and animal extinctions in this century.
全球变暖的一个后果就是物种灭绝。有力证据显示全球变暖将会是这个世纪里植物和动物灭绝的罪魁祸首。
2 .So we are considering various strategies to help some threatened species survive this unprecedented, this warming trend which, as you know, is caused mainly by green houses gases produced by the burning of fossil fuels.
因此，我们正考虑不同对策去帮助濒临灭绝的物种生存下去。如你所知，全球变暖主要是由燃烧化石燃料产生的温室气体引起的。
第三段
1 .The most radical strategy being debated among conservation biologists is Assisted migration.
动物保护学家们提出最基本的对策就是协助迁徙。
2 .Assisted migration means picking up members of the species or members of a group of interdependent species and physically moving or translocating them.
协助迁徙意味着：选择某一物种中的成员，或者一个群体或共生物种的成员，将它们移动或转移走。
3 .Translocating threatened species to a cooler place to higher latitudes or higher elevations for example.
比如，把濒临灭绝的物种转移到更冷的地方，更高的纬度，或更高的海拔。
第四段
1 .Now migrations are natural survival strategy.
现在，迁徙是动物能够自然存活的一个方案。
2 .Over the past two million years, colder glacial periods have alternated with warmer inter-glacial periods.
在过去200万年里，更冷的冰川期和更温暖的间冰期是交替进行的。
3 .And so in response to this gradual climatic swings, some species have shifted their ranges hundreds of kilometres.
因此，为了适应气候的逐渐变化，一些物种已经把自己的居住范围转移到几百千米之外了。
第五段
1 .So perhaps you are wondering why not let nature take its course now.
所以你可能想知道为什么不让自然来掌管一切呢？
2 .Well we can't.
好吧，我们不能
3 .The main problem is today's fragmented habitats.
主要问题是现如今那些支离破碎的栖息地。
4 .During previous inter-glacial periods, when glaciers were retreated they left behind open land in their wakes.
之前的间冰期中，冰川融化后会留下开阔地，这些也为下一次冰川期做准备。
5 .Today human development has paved over much of the natural world.
现在，人类的发展过多的破坏了大自然。
6 .Ecosystems are fragmented, housing developments, highways, and cities have replaced or sliced through forests and prairies.
生态系统支离破碎。住房，高速公路，和城市已取代或者分解了森林和草原。
7 .There are few corridors left for species to migrate through without help.
在没有帮助的情况下，只剩下很少的地方让动物迁徙
8 .So conservationists are trying to save as many species as possible.
因此，动物保护学家正在尝试拯救尽可能多的物种。
第六段
1 .Now, assisted migration could become a viable part of our rescue strategy, but there are a number of uncertainties and risks.
现在，协助迁徙可能成为拯救计划中不可或缺的一部分，但是它却面临着很多的未知和风险。
2 .Without more research we can't predict if assisted migration will work for any given species.
果不做更多的调研，我们不可能预测协助迁移是否对每一物种都奏效。
3 .A translocated species could die out from lack of food for example.
比如，一个被转移的物种可能由于缺乏食物而灭绝。
4 .At the other extreme, we might successfully translocate the species but within five or ten years, that species could proliferate and become an invasive species.
另一种极端情况，我们成功的协助迁移了物种，但是五年或十年内，这一物种数量激增，变成一个入侵种
5 .Like a non-native plant that chokes out native plants by hogging the nutrients in the soil.
像一株非本地植物可以通过独占土壤中的营养来遏制本地植物生长。
6 .Translocated animals can become invasive too.
迁移动物也可以成为入侵种。
7 .It happened in Australia.
澳大利亚曾发生过此类事情。
8 .The cane toad was introduced back in 1935 to control an insect pest that was destroying Australia sugar cane plantations.
为了防止害虫继续破坏澳大利亚的蔗糖种植园，蔗蟾在1935年被引进。
9 .But the cane toad itself became a pest and it destroyed much of the wild life on that continent.
但是蔗蟾他们自己却变成了害虫，并扼杀了当地大量的野生生物。
第七段
1 .Also, many species are interdependent, intimately connected to one another.
同时，很多物种是共生的，这些物种之间是紧密联系的。
2 .Like animals that eat a certain plant and that plant relies on a certain fungus to help it get nutrients from soil.
比如动物吃某种植物，这种植物依靠某种真菌帮助自己获得土壤中的营养
3 .And on a certain insect for pollination, we probably have to translocate entire networks of species.
，也需要依赖某种昆虫授粉。对于这种情况，我们可能必须转移整个生态网中的所有物种
4 .And it's hard to know where to draw the line.
而且很难了解如何划清该转移和不该转移的物种界限。
5 .And in addition to all that it's not even cleared that the assisted migration or any migration for that matter will help at least for some species.
除了以上提到的，我们甚至不清楚协助迁徙或者任何迁徙行为是否会真正帮到某些物种。
6 .Earth was already at one of its warm inter-glacial periods when we started burning fossil fuels.
当我们开始燃烧化石燃料的时候，地球已经进入到温暖的间冰期了。
7 .And in the 21st century, global temperatures are expected to rise two to six degrees.
进入21世纪，全球温度经预测会上升2-6度。
8 .That rate of heating is far greater than during the last glacial retreat some twelve thousand years ago.
这个幅度和一万两千年前冰河时期结束后的气温回升幅度相比，要大很多。
第八段
1 .Um... whether to use the assisted migration, this debate is mostly within the biology community right now.
关于是否采用“协助迁移”的争论目前主要集中在生物领域内。
2 .But the ultimate decision makers, in United States at least, will be the government agencies that manage natural resources.
但是，最终决策者，至少在美国，将会是管理自然资源的政府机构。
3 .Assisted migration really needs this level of oversight and soon currently there is no public policy on using assisted migration to help species survive climate change.
协助迁徙确实需要这个层面上的远见去尽快解决问题。当下，针对使用协助迁徙帮助生物物种在气候变迁中存活下来这一点没有任何公共政策。
4 .People aren't even required to seek permits to move plants or invertebrate animals around as long as they are not classified as pests.
只要没有被定义为害虫，人们就不需要去寻求许可来移植植物或无脊椎动物去别的地方。
5 .In one case, a group of conservationists has already taken it upon itself to try on their own to save the endangered tree, the Florida Torreya tree through assisted migration.
有一个例子，一队环保主义者已经依靠自己的力量通过协助迁移拯救了濒临灭绝的树种--佛罗里达榧子树。
第九段
1 .There is only about a thousand individual Florida Torreyas left and global warming is expected to significantly reduce or eliminate this tree's habitat.
前仅剩下大概1000棵佛罗里达榧子树。全球变暖将会导致此种树木的大量减少或者会摧毁这种树的栖息地。
2 .So this conservation group wants to translocate seedlings, Florida Torreya seedlings, 500 kilometres north, in order to expand the species' range.
因此，这队环保主义者想转移这个树种--佛罗里达榧子树种--向北延伸5000千米，目的是扩大这一树种的生长区域。
3 .The group believes that its effort is justified, but I and many other biologists will be watching very closely how this maverick group makes out because, like I said there could be unintended consequences.
这些人相信，努力就会有回报，但是我和其他生物学家将密切关注这些标新立异的环保主义者，因为就像我说过的，可能会产生意想不到的后果。