What a waist of money for the "Study". Of course the wolves were killed outside the refuge because the Feds refused to allow control in the refuge. Of course wolf populations declined in the refuge because when they left it they could be killed. The only value to the study and article was the statement that wolves responded immediately and produced more pups. They had higher survival rates than normal because the prey was now more plentiful and competition reduced. 
Wolf sterilization was a joke to appease the PETA people and tourism boycott people trying to blackmail and terrorize Alaskans.  Canada did it right. When threatened they went in and killed 80 wolves immediately and said "we're done". Peta never had a chance to raise a dime and ceased threatening Canada.  Predator control has never had long lasting effects in Alaska. Non-management will put Alaska back into a wide spread predator pit quickly. Just like it was 130 years ago when they prey and predators were few.