keystone parasite

例句：

1. 1. The keystone parasite has been causing significant damage to the ecosystem.
   关键石寄生已经对生态系统造成了严重的破坏。
2. 2.The researcher found that the keystone parasite was responsible for the decline of the local species.
   研究者发现，关键石寄生是导致当地物种数量下降的原因。
3. 3.The keystone parasite is a fascinating organism that plays a crucial role in maintaining the balance of the ecosystem.
   关键石寄生是一种令人着迷的生物，它在维护生态系统平衡中起着至关重要的作用。