Another very interesting case study is the Lolo Zone Elk herd in Idaho. At the time of wolf introduction into Idaho, 1995, the Lolo Elk herd numbered in excess of 16,000 animals and the population had been stable or increasing since the 1970’s. 20 years later in 2015 the herd numbered less than 1,000 animals according to IDF&G surveys and it continues to dwindle. Calf recruitment has been well below sustainable for a decade or more.
One of my favorite wilderness units, Unit 26, had a healthy and increasing moose population until about 2000. You will not find a moose in Unit 26 today.
As has been mentioned, there are a number of other factors that affect game numbers and wolves are not the sole factor in the decline of game numbers anywhere. However, when there is already a heavy predator load and then wolves are added to the mix, it is inevitable that game numbers are going to decrease. At least until the new equilibrium is reached. In addition, when the inevitable hard winters arrive and with them increased game animal mortality, herds are much slower to rebound compared to what they once were. We are experiencing this currently. 3 of the last 5 winters have been hard on game.
I have seen the Isle Royale study and YNP info tossed around in abundance. They are about as applicable to the Idaho wolf situation as comparing elephant in India to elephant in Botswana. Chalk and cheese.