Throughout the school year, students from a number of schools go on field trips to Natural Lands Trust Preserves and other natural places as a part of our "Sense of Place" Program. This program is designed to expose kids to protected lands in their area and introduce them to environmental science. Many of these trips involve canoing or kayaking on local lakes and streams, and teach the kids about the creatures living in these bodies of water.
Sometimes, though, more abstract lessons can be taught with a canoe. This picture shows students and teachers taking a break from their study of the river to test the carrying capacity of a 16-foot canoe. They got as many as seven in the boat at one point, though it became increasingly unstable with anything more than two adults, as is seen in this next picture.
This experiment with the canoe might be seen as a metaphor for the dilemma that we face with our nature preserves: What is the human carrying capacity of a preserve? Over what number of visitors does the preserve become increasingly unstable and difficult to maintain, and at what point does it simply sink as a preserve and become a human amusement park? These are questions that we ponder and struggle with at Natural Lands Trust.
After sinking the canoe, the students learned the Boy Scout "airplane" technique for emptying and refloating a sunk canoe in the middle of a lake without bringing it to shore. Although a preserve can't easily dump all its visitors and refloat itself as a nature preserve, there are things that we can do to help prevent it from "sinking" in the first place, such as containing human visitors to trails and other designated areas. It's not a complete answer to the question, but it's a start.