Project Director

Boyd, Jennifer

Department Examiner

Aborn, David; Klug, Hope


Dept. of Biological and Environmental Sciences


University of Tennessee at Chattanooga

Place of Publication

Chattanooga (Tenn.)


An important ecological question that remains unanswered is why some species are rare while others are common. Because the natural world is dynamic, in order to persist, species must successfully respond to the environmental changes they experience. The ability to be plastic may be especially important to the survival of species in the face of rapid environmental change because such quick change does not offer species time to migrate or adapt. Consequently, differential plasticity between rare and common species, with rare species possessing less plasticity than common species, could help explain the differing successes of persisting in a large geographic distribution. Here, I used a comparative trait-based approach to assess the ability of a rare and common congeneric species pair to acclimate to environmental change with a focus on growth measures. Specifically, I evaluated the growth and plasticity of rare Borodinia perstellata and common B. laevigata to altered light, water, and temperature conditions in environmentally controlled growth chambers. I found that both species respond similarly to different environmental conditions and have similar plasticity, but some of my results suggest that the rare Borodinia perstellata could be generally less plastic than the common Borodinia laevigata. Specifically, B. laevigata possessed greater plasticity to grow taller and more leaves in both the altered water and temperature conditions while B. perstellata only contained greater plasticity for growing more shoot mass in the light condition. Since the common B. laevigata was found to be more plastic across a wider range of environmental differences than the rare Borodinia perstellata, the hypothesis that differential plasticity can help explain species rarity and commonness is limitedly supported, but further research should be conducted to confirm the hypothesis.


I thank the National Science Foundation for funding this experiment as a part of a larger project to assess the differential plasticity between rare and common plant congeners (Award #165562 to J. Boyd). My work also was supported by a Student SEARCH grant from the University of Tennessee at Chattanooga. I appreciate my director, Dr. Jennifer Boyd, for her guidance on completing this Departmental Honors thesis.


B. S.; An honors thesis submitted to the faculty of the University of Tennessee at Chattanooga in partial fulfillment of the requirements of the degree of Bachelor of Science.




Rare plants; Endangered plants; Conservation of natural resources


Rarity; Commonness; Plasticity; Acclimation; Borodinia; Southeast


Environmental Sciences

Document Type



23 leaves