Student or Learner
I would like to know if "crowding" is a Gerund or a Participle.
Watermilfoil grows in dense, fibrous stands that foul propellers and give swimmers nightmares. Most worrisome is the damage it does to native aquatic plant species, crowding them out and unbalancing the ecosystems they anchor and all the organisms that depend on them.
I consider it a participle modifying 'it'.
I am not a teacher.