Running Up Against Limits
Something as insignificant as a pine nut can determine the fate of the endangered Amur tiger, arguably the most magnificent tiger in the world. That is the crux of research conducted by environmental sciences graduate student Nancy Sherman. Amur tigers prey on deer and wild pigs in the forests of southeast Russia. These animals, in turn, eat acorns and nuts. Remove the nut-producing trees, and the tiger’s prospects darken considerably.
Sherman set out to determine if climate change could put the Amur tiger at risk by altering the composition of the forest. She turned to a pioneering model of forest succession called FAREAST, which her adviser, Professor Hank Shugart, had developed.
Sherman’s first challenge was to adopt the model for modern computing. She turned to Katherine Holcomb, a staff member of the University of Virginia Alliance for Computational Science and Engineering (UVACSE), to translate FAREAST into a computer language she could run on her laptop and on the U.Va. computer cluster.
FAREAST had been validated against forest inventory data in Russia and China, but not on the ground. Sherman traveled to Russia to collect data at 12 sites and test the program. She also adjusted the model to incorporate the effects of climate change.
After running her model, Sherman found that temperature increases expected by the end of the next century would constrict the tiger’s habitat dramatically. As the climate warms, a critical nut-producing species, the Korean pine, would begin to disappear from the tiger’s range. “If the tiger is to survive, it will have to migrate north out of areas where it enjoys some protection,” Sherman said. “And this could make it even more vulnerable to the most significant threat to its existence, illegal hunting.”