It could also be argued that removing individual animals from the wild are potentially threatening the population of wild species.
In this sentence, the subject removing individual animals from the wild does not 'agree' with the verb are.
Subject/verb disagreement happens when..
the subject is singular and the verb is plural e.g. 'He go..'
the subject is plural and the verb is singular e.g. 'They goes..'
It's possible that the writer was trying to make animals (plural) agree with the verb, and that's why he or she chose are (also plural). However, the main noun in the subject is removing (singular), and so the sentence should read:
..removing individual animals from the wild is potentially threatening..
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I've noticed that - at least among Indonesians - this error is extremely common when the main noun of a noun phrase is constructed using __ing, which is quite common in much academic writing.
When you're deciding how to make verbs agree with nouns, first of all identify which noun in the subject is the main noun. Then select your verb accordingly.
Practice
Hanging out with friends at the weekend 1. lots of fun. On a typical Saturday, we go to the beach. Swimming when the waves are high 2. one of our favourite activities. Towards the end of the day, if it's really hot, drinking a few beers with friends 3. not unusual. Budi and Simon sometimes 4. too much. Simon sometimes 5. 5 beers before heading home!