How were the statistics on manure tonnage, etc., arrived at? Did N.P. rangers actually do a scientific study, or are those stats approximations based on guess work? I cannot imagine any ranger willing to carry scales around the mountains to measure poop! Unless the measurements were made closer to the pack stations, where the animals are more likely to take a dump in an uphill section of a trail.
Are there any statistics on the environmental impact of two-legged traffic in the backcountry? Tonnage of trash, human waste, trampled meadows, trail erosion, domestic dog messes, etc.? How about a fair comparison?
I agree that any kind of disfiguring of the wilderness by humans or animals can leave a less-than-delightful visual experience. But you seem to be more concerned, in your comments, with the impact of pack animals, rather than hiker impact.
Perhaps the ultimate solution would be to ban all access to the backcountry, by anyone, including researchers and rangers, and let the wilderness recover for a few decades.
