More people, more damage
I have worked in the backcountry of Dinosaur National Monument for four years and have had numerous encounters with groups from the Colorado Outward Bound School. They have been using this area for a number of years and frankly, it shows. Mark Udall of COBS says they "thoroughly instruct ... students to diligently avoid cryptobiotic crusts and to travel and camp on slickrock" (HCN, 6/27/94).
This has not been the case in Dinosaur. The route that Colorado Outward Bound travels (used almost solely by them and rarely by other visitors) is now highly visible from viewpoints in the monument as a clear trail through cryptobiotic soils.
Because their trips include "solos," there are spiderwebbing side trails where students fan out, trip after trip, year after year. Observation shows that this web of side trails has gotten more extensive over time. "Half the amount of instructors and students' would certainly reduce this impact.
I always ask every group I encounter if they discuss group size as a facet of minimum impact camping. Invariably eyes glaze over and the conversation drifts off; this concept is apparently not to be seriously considered.
It doesn't matter how clean a camper one is; 10 clean campers do more damage in these fragile environments than six. If Colorado Outward Bound is truly committed to ethical wilderness education, they need to stand behind reduced group-size limits.
Green River, Utah