[Grammar] leading to the decline of native species of mammals and reptiles.

[ambitious-girl]

I don't understand the use of the -ing form of the verb "lead" here, because there is no ',' before "leading".

When farmers tried to eliminate the cane beetle by introducing the South America can toad, the results were catastrophic. The cane toad didn't eat the cane beetle and the toad population spread rapidly leading to the decline of native species of mammals and reptiles.

Source: Vocabulary for IELTS Cambridge Unit 9

 

[emsr2d2]

I don't understand the use of the -ing form of the verb "lead" here, because there is no ',' before "leading".

When farmers tried to eliminate the cane beetle by introducing the South America cane toad, the results were catastrophic. The cane toad didn't eat the cane beetle and the toad population spread rapidly, leading to the decline of native species of mammals and reptiles.

Source: Vocabulary for IELTS Cambridge Unit 9

There should be a comma.