Sharks limit the abundance of animals which would otherwise overgraze these essential plants.

鲨鱼限制了动物的数量，否则这些动物会过度放牧这些重要植物。

Today, we're giving some attention to the unsung heroes of the botanical world — those essential plants that were the first to join the party, but that tend to lie low.

今天，我们来关注一下植物界的无名英雄——这些必不可少的植物是第一批加入这个行列的，但它们往往很低调。