Complex sentence: The population was estimated at 600 in 1997, below 100 in 2014, approximately 60 in 2015 and approximately 30 in November 2016, leading to the conclusion that the species will soon be extinct unless drastic action is taken.
Split into simpler sentences: The population was estimated at 600 in 1997, but dropped below 100 in 2014, putting it in imminent danger of extinction. That number was updated to approximately 60 in 2015 and fell to approximately 30 in November 2016, leading to the conclusion that the species will soon be extinct unless drastic action is taken.