01

　　When one of these noneconomic categories is threatened and,if we happen to love it.We invert excuses to give it economic importance.At the beginning of century songbirds were supposed to be disappearing.(46)Scientists jumped to the rescue with some distinctly shaky evidence to the effect that insects would eat us up if birds failed to control them.The evidence had to be economic in order to be valid.

　　译：

　　当某一类没有经济价值的物种受到威胁，而我们又恰巧喜欢这类物种时，我们就会编造一些借口来赋予它经济重要性。在本世纪初，鸣禽原本就要消失了。(46)科学家们急忙挽救，但提出的证据非常站不住脚，这些证据的大意是:如果鸟类不能控制昆虫的数量，昆虫便会吞噬我们人类。证据必须有经济价值才会有效。

　　02

　　A parallel situation exists in respect of predatory mammals and fish-eating birds.(48)Time was when biologists somewhat overworked the evidence that these creatures preserve the health of game by killing the physically weak,or that they prey only on“worthless”species.Here again,the evidence had to be economic in order to be valid.It is only in recent years that we hear the more honest argument that predators are members of the community,and that no special interest has the right to exterminate them for the sake of a benefit,real or fancied,to itself.

　　译：

　　食肉哺乳动物和食鱼鸟类也存在类似的情形。(48)曾经有段时间，生物学家有点滥用了这样一种证据，即这些生物通过杀死体弱者，或者仅仅捕食“没有价值的”物种，来保持猎物种群的健康。这再次说明证据必须有经济价值才会有效。直到最近几年，我们才听到更为诚实的论点:食肉动物是这个群落的成员，没有任何特殊利益群体有权为了自己的利益而消灭它们，无论这种利益是真实的还是假想的。

　　03

　　To sum up:a system of conservation based solely on economic self-interest is hopelessly lopsided.(50)It tends to ignore,and thus eventually to eliminate,many elements in the land community that lack commercial value,but that are essential to its healthy functioning.It assumes,falsely,I think,that the economic parts of the biotic clock will function without the uneconomic parts.

　　总而言之，一个只基于经济利己主义的保护系统是完全失衡的。(50)这种保护系统往往忽视了地群落中诸多缺乏商业价值，但对其健康运行至关重要的物种，从而最终导致它们的灭绝。我认为，它错误地认为在没有无经济价值的部分的情况下，生态系统有经济价值的部分依然可以正常运行。