Research
My research centers on the ecology and evolution of species interactions and responses to climate change. Using observational, experimental, and modeling techniques, I explore drivers of variation in species’ population dynamics and their encounters with interacting species. I find research to be an excellent avenue for developing students’ skills in analytical thinking, collaboration and communication while learning biological principles. In an era of large-scale perturbations, universal science literacy is essential for creating a more informed and engaged public capable of solving the complex problems of our world.
Recent Research Projects
Climate change impacts on mutualisms in an evolutionary & ecological context
Interspecific interactions are critically dependent on the phenological and morphological overlap of the partners, and changes in climatic conditions may disrupt this synchrony. I study the effects of climate variation (in time and space) on plant signals, insect behavior, and ultimately ecosystem services. Historical data reveal altitudinal variation in the degree of bumblebee partitioning of floral resources and the structure of plant-pollinator networks in the Rocky Mountains (Miller-Struttmann and Galen, 2014). Comparison of historical and contemporary collections of Colorado bumble bees illustrated the evolution of shorter tongues in response to flower deficits (Miller-Struttmann et al. 2015). However, plants do not show similar declines in flower tube depth, indicating the emergence of a functional mismatch between bumble bees and their historical host plants.
There is abundant evidence that plants and animals are responding to climate change independently; however, very few studies have explored how changes in species’ distributions, phenology, and morphological traits will affect their encounters with and dependence upon each other. I use archived and contemporary data to explore the contributions of evolutionary history, species traits, and local habitat on species responses to climate change. In collaboration with scientists at the Missouri Botanical Gardens and Maryville University, I identified a strong effect of seasonality on phenological shifts of more than 100 plant species over a 70-year period at the Missouri Botanical Garden field site, Shaw Nature Reserve, in eastern Missouri. Plants are blooming for longer time periods in late-summer and fall, which has led to a dramatic (i.e., 2.5 fold) increase in the diversity of co-blooming species.
Determinants of rare plant range distributions
Scientists have long explored the factors that restrict species ranges, and numerous mechanisms have been proposed, including ecological tradeoffs, dispersal limitation, local adaptation, and neutral processes. For my dissertation work, I considered how the relationship between local-adaptation to climate and reproductive specialization affects range restriction of three habitat specialist (HS) plant species endemic to the Ozarks. The Ozark glades are xeric, rocky habitats that are fragmented in space and contain many endemic species. I found that HS species are not more resistant to abiotic stress but have more specialized pollination systems than CC. HS species had larger flowers, higher nectar quality, and fewer species of pollinators, indicating that pollination mutualisms play a major role in reproductive success within the fragmented Ozark glades (Miller-Struttmann, 2013). Moreover, the HS and CC species exhibited different resource-allocation strategies with HS species producing fewer offspring of higher quality. High offspring quality may enhance survival rates and population viability in more stressful glade habitats.
