Jason--Thanks. I hadn't thought about transport by horse, although it is an obvious possibility. I really wish the Park would ban use of horses, although I know just saying that will raise some hackles. Yet anyone who spends much time in the Park has to recognize the undeniable fact that horses do considerable damage, especially on steep trails. There are places, especially on the Tennessee side of the Park, where horses have turned high elevation trails into gullies. Then there's the stink and general mess in horse camps.
At least you find a few specks, and the fact that some were tiny suggests at least a bit of population recruitment. That being said, the overall scenario doesn't look good.