Mosses as Successional Plants

After a large scale disturbance such as a forest fire or glaciation, mosses are one of the initial colonizers of open soil. The website for the Glacial Bay National Park has a nice series of successional photos with mosses as the first stage. The mosses create a moist environment that can favor seed germination of the flowering plants that will come after the mosses.

The website for the National Parks of Alaska has a glacial successional exercise for students to carry out in the classroom. This exercise examines the interaction between glaciers and biological ecosystems. In part II the students make a "glacier" out of a large ice cube and expose plants to the cold and examine the effects. They suggest using Impatiens plants, but I think that mosses would be great to use as well.

I have found mosses very easy to grow in the lab. I either collect sporophytes and then sew the spores onto fresh soil. Or I take leafy gametophytes from the wild and grind them up in some water using a mortar and pestle. Then I pour the moss slurry onto the soil. With a lid and some plastic wrap, protonema start to grow in a couple of weeks and there are leafy gametophytes within a month. I am not sure if as dramatic a response to the cold would be seen with the mosses. Where it does become cold and snowy during the winter, the mosses stay bright green and alive beneath the snow pack. So it would be really interesting to see how they respond to cold without the insulating effects of a snow pack. Overall I think that it looked like a pretty cool exercise for teachers to use in the classroom.