PARENT SESSION
Poster Session #41: Plant Demography.
Thursday, August 9, 2001. Presentation from 3:30 PM to 5:00 PM. Exhibition Hall

Recensus of an Indiana nature preserve to examine goldenseal population demography.

Sanders, Suzanne¹, McGraw, James¹, ¹

ABSTRACT- Goldenseal (Hydrastis canadensis) population dynamics are poorly understood, particularly in reserves where harvest is prohibited. We examined net population change of H. canadensis over 26 years in Bryan Nature Preserve in central Indiana. Individuals were mapped and censused in 0.1 hectare quadrats over the entire preserve, repeating a similar procedure carried out by others in 1974. The net trajectory of the natural population was negative: H. canadensis was present in 46 quadrats in 1974, but had become extinct in 31 of those quadrats and decreased in 15; three quadrats contained new populations. Only 10 of the 99 populations present in 1974 were relocated. Fifteen new populations were found in 2000. Populations in edge quadrats had higher survival than those in the interior, and extinction probability was not dependent of population size. The dramatic decline in H. canadensis abundance is unusual among long-lived clonal plants and it is difficult to ascertain the cause. A severe wind and ice storm occurred at the preserve in February 1991, downing large trees. Additionally, the site appears to be in a state of ecological transition from an oak-hickory forest toward a sugar maple dominated stand. Both of these events will cause shifts in understory light levels and can impact the number of suitable sites for H. canadensis. Poaching was not apparent. Periodic recensusing of this preserve will increase our understanding of H. canadensis population dynamics.

KEY WORDS: Hydrastis, recensus, clonal plant, perennial plant