Lloyd R. Stark

Associate Professor

Ph.D. Pennsylvania State University, University Park

Bryophyte Ecology: Stress, Reproduction, Conservation

LRS@unlv.nevada.edu

The primary focus in my lab is an investigation into unbalanced sex ratios in bryophytes with particular attention to sex-specific responses to stress as mediated by the costs of sexual reproduction. Species under study are the cosmopolitan moss Bryum argenteum, the desert moss Syntrichia caninervis, and the model organism Physcomitrella patens. Types of stress responses that may be helpful in understanding the female-biased sex ratio that characterizes most bryophyte species include gametophytic and sporophytic dessication tolerance (DT), thermotolerance, nutrient stress, microsite disturbance, and overgrowth competition. A current problem under study is the relationship between stress and offspring sex ratios. My graduate students are studying (i) predictive models of species distribution in deserts, (ii) the relationship between DT and cold tolerance, and (iii) heat shock protein expression during thermal stress.

Selected Publications

• Stark, L. R., J. Brinda, and D. N. McLetchie. 2009. An experimental demonstration of the cost of sex and a potential resource limitation on reproduction in the moss Pterygoneurum (Pottiaceae). American Journal of Botany 96: 1712-1721.
• Stark, L. R., D. N. McLetchie, and S. P. Roberts. 2009. Gender differences and a new adult eukaryotic record for upper thermotolerance in the desert moss Syntrichia caninervis. Journal of Thermal Biology 34: 131-137.
• Cole, D. C., L. R. Stark, M. Bonine, and D. N. McLetchie. 2009. Transplant survivorship of bryophyte soil crusts in the Mojave Desert. Restoration Ecology, in press.
• Stark, L. R., M. J. Oliver, B. D. Mishler, and D. N. McLetchie. 2007. Generational differences in response to desiccation stress in the desert moss Tortula inermis. Annals of Botany 99: 53-60.
• Brinda, J. C., L. R. Stark, J. R. Shevock, and J. R. Spence. 2007. An annotated checklist of the bryophytes of Nevada, with notes on collecting history in the state. Bryologist 110: 673-705.
• Proctor, M. C. F., M. J. Oliver, A. J. Wood, P. Alpert, L. R. Stark, N. L. Cleavitt, and B. D. Mishler. 2007. Desiccation-tolerance in bryophytes: a review. Bryologist 110: 595-621.