英语翻译Low levels of straying are crucial,since the process pro

英语翻译
Low levels of straying are crucial,since the process provides a source of novel genes and a mechanism by which a location can be repopulated should the fish there disappear.

should the fish there disappear楼主应该是困惑在这里吧,原句中不差成分,所以,上述那几个单词,不是状语,就是同位语……这里是if虚拟语气的特殊用法,还原：if the fish there should disappear.从句与将来相反…句子那样写,是可以省去if的…
低程度的staying是至关重要,因为这个过程提供新基因资源和一种机制,当那儿的鱼消失了,可以重新有鱼
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stray只知道是彷徨的意思,翻译不出,看语境吧……
还有就是,by which,which带指前边and的两个成分,by为通过之意,不能理解为where……