Print PageClimate change, whether referring to historic ice ages or contemporary shifts in global climate patterns, has been linked to wide-ranging and regionally variable changes in biotic communities. Environmental shifts predicted for the southwestern United States include increased temperature and aridity, elevated levels of atmospheric CO2 and increased risk of wildfire. The impacts of these shifts on plant and insect communities on the Colorado Plateau are currently poorly understood. We tested the following hypotheses to increase understanding of the effects of warming on Penstemon palmeri (Plantaginaceae): 1) At lower elevations and higher temperatures, P. palmeri is more productive in terms of vegetative and reproductive characteristics, and experiences phenological shifts towards flowering and fruiting earlier; and 2) Pollinator community composition for P. palmeri differs along an elevation gradient. We collected data on vegetative and floral phenology and phenotype, pollinator visitation rates, and insect community composition at 10 sites along an elevation gradient in Zion National Park, Utah. An experimental study using two growth chambers was conducted (simulating current mean springtime temperatures and forecasted springtime temperatures for the year 2050) to assess direct effects of warming on phenology and phenotype.
Results/Conclusions
Preliminary data analyses indicate that populations at lower elevations produce more and taller stems per plant, more above- and below-ground biomass, larger fruits, and seeds that germinate more quickly than populations at higher elevations. Further analyses will be performed to test for differences in floral morphology and reproductive fitness of P. palmeri and differences in the pollinator community along the elevation gradient. P. palmeri is an important species in regional restorations. Results from this study will provide valuable insight into the future of the species and its pollinator community.
