My understanding is that the important aspects are that Mule Deer populations have been on a decline. The main lever the CPW has to pull that adjusts game numbers is hunting, and they have reduced that all they can in certain areas (99%). Now they need to look to other influences on the deer population. They do not fully understand the influence of bear and lions so they want to conduct a study. They have chosen two areas where they have significant data on deer populations so they can conduct a study and see the resulting impact on deer population.
You understand it correctly. In essence, CPW is testing the concept of a predator pit. The predator pit idea is generally the scenario where there is a very small, isolated population in the presence of a predator population that will not allow enough young to live to breeding age. But this is usually in the context of a much smaller population than the deer numbers we have.
Secondly, mule deer populations in all the interior west began this decline in the early 1980's, and accelerated in the late 80's thru the late 90's. Limiting deer licenses here in Colorado helped the statewide population, and the deer population increased some. The drought that began 15 years ago is thought to have caused a decrease once again, but now that we have had a number of normal years (or as normal as it is going to get given the current weather/climate scenario), and deer populations have if anything decreased again.
By the mid 60's we had 1.1 million deer in the state. Today we have 450,000. Why the decline? 4-5 western states have done studies, with Colorado having a series of studies since the late 90's, and nobody has been able to come up with definitive answers about what is going on with muleys.
If you ask me......although no correlation has been established, the elk population boom has coincided with the deer declines--there is only so much habitat to go around and elk are winning.
And, here in the west we have been successful in suppressing fires in the winter and transition habitat over the last 75 years. Muleys are browsers and the browse is becoming decadent.
How many deer the average lion kills is not known very well. And can vary a LOT depending on the individual lion and habitat the lions live in. There is some evidence that some individual lions live on small game and other small critters (even frogs) and only occasionally kill big game.
We know bears and coyotes intentionally hunt fawns in the spring, and there has been lots of bear and coyote scat analyzed that demonstrate they are eating neonate fawns.
The lion quotas in Colorado have been tripled since the 80's, but that doesn't seem to have much effect on deer declines. There are some ideas being floated about new seasons for bears and CPW has increased the September bear tags a fair amount the last few years.
We need to learn how to be more successful killing bears and coyotes, thats for sure. Hound hunting seems to be doing a decent job keeping lions in check.
In other words, state wildlife management agencies have researched, study, messed with seasons/quotas for deer and predators, but nothing has helped muley populations in the interior west.
I think at this point the CPW has to try something new, and although this study has been a bit controversial (especially with my former wildlife professors at CSU!) I support what they are doing.
Casey