A Novel Experimental Design for Examining Bryophyte Response to Increased Ultraviolet Radiation

Bryophytes were among the earliest colonizers of terrestrial environs, and despite their interesting life histories and population dynamics, they are rarely used in undergraduate introductory biology labs. In an inquiry-based laboratory exercise for introductory biology, students implement a controlled experiment to investigate effects of increased ultraviolet radiation (UVR) exposure on liverwort gemmae. The exercise integrates impacts of climate change on plant populations with experimental design and liverwort ecology. It uses a readily available and easily propagated thallose liverwort. Liverworts reproduce both sexually and asexually, but asexual reproduction is imperative for population persistence. In the laboratory exercise, students explore how the environment impacts colonization of asexual propagules using a novel design that underlines the importance of randomization and introduces basic statistical techniques. The experiment can be completed in two, 2-hour laboratory periods and concepts and techniques are transferrable to a variety of learning environments. After the first implementation of this laboratory exercise, the majority of students agreed that they learned more about bryophytes, experimental methods, and reporting statistics in lab reports.