One of the hallmarks of a healthy population—be it man, beast, bee or baobab tree—is the presence of a wide variety of genes that can boost survival under a wide range of future conditions. But what if a relatively few individuals with relatively few gene variations get cut off from the rest? Will they collectively have what it takes, gene-wise, to weather the environmental challenges of tomorrow?
Such genetic isolation is exactly what happened as the great prairies of North America got sliced and diced into fragments by farms, roads, and towns over the past two centuries. Now Ruth Shaw, a professor in the Department of Ecology, Evolution and Behavior, is studying the ecology and evolution of prairie plants in hopes of figuring out how to keep then from going the way of the passenger pigeon.
The core of Shaw’s work is an initiative started by then-Ph.D. student Stuart Wagenius nearly two decades ago that looks at the genetics of perennial plant purple coneflower (Echinacea angustifolia) in a 25-square-mile area in western Minnesota. Each summer since 2000, Shaw, Wagenius (now a conservation scientist with the Chicago Botanic Garden) and a bevy of enthusiastic students working on the Echinacea Project have documented diverse aspects of individual plants’ lives, from growth to number of leaves to flower and seed production to extent to which aphids and other plant eaters are nibbling away at them.
“I just love being out there,” Shaw says. “The prairie parcels that we work in, even though they’re very severely diminished in size, still have very beautiful arrays of diverse species that are characteristic of the prairie. It is just a beautiful area to work in, and an enjoyable group of people to work with. … That's pretty hard to beat.”
Shaw, who first become interested in biology as a child literally following in the footsteps of two naturalist parents, is fascinated by the core basic science question the research attempts to answer: What does habitat fragmentation mean for basic ecological and evolutionary processes—from absence of fire to changing availability of pollinators to inbreeding? In addition to a better understanding of how ecology and evolution intertwine, the research so far has yielded a new statistical approach known as aster modeling to predict from field data the fitness of individual plants and how populations are likely to grow or shrink, as well as a suite of computer programs known as Quercus for analyzing the complex data to predict, for example, how quickly species might be able to adapt to changing climate.
In addition to the theoretical aspects, Shaw’s work also informs conservation in action. The Minnesota Department of Natural Resources consults her and her colleagues when making decisions about acquiring and managing prairie remnants in the state. In addition, she just won a three-year grant from the Legislative-Citizen Commission on Minnesota Resources to study survival in six prairie plant species around the state and produce from the results practical recommendations for managing prairie in a way that preserves genetic diversity as well as individual plants and patches. The analytical software developed through the Echinacea Project, Shaw says, “are definitely tools that will put us in the position to get the most insight possible from the data we get there.”
Shaw just began work on another project focused on partridge pea, a prairie annual, that will use aster modeling to look at multiple traits at once and assess the extent to which genetic variation within a population gives it the tools to thrive in future environments by comparing fitness of successive generations. The research, Shaw says, is quite relevant for developing conservation policy in today’s quickly and unpredictably changing world.
“One of the key questions is whether populations of all the many species we have can adapt fast enough given the very high rate of climate change and change in the environmental attributes due to anthropogenic alterations,” she says. “These studies [definitely] bear on that question.”
– Mary Hoff