GWD第一套里面第二套阅读关于salmon洄游与基因多样性那篇有句话我不是很明白:the process provides a source of novel genes and a mechanism by which a location can be repopulated should the fish there disappear.请问这句话里面红字部分是什么意思呢?是否等同于if the fish there were to disappear?或者were the fish there to disappear?不明白,请nn多多指教