PARENT SESSION
Oral Session #64: Plant Population Ecology.
Presiding: S. Collins
Wednesday, August 7. 1:00 PM to 4:45 PM. Gila Meeting Room, TCC.

Recruitment and fire: how prescribed burns affect seedling recruitment in the native prairie plant Echinacea angustifolia.

Wagenius, Stuart^*,1,2, Shaw, Ruth², ¹ Chicago Botanic Garden, Glencoe, IL² University of Minnesota, St Paul, MN

ABSTRACT- Prescribed burning is a common management practice for prairie remnants because it decreases the abundance of many invasive plants while increasing growth and flowering of fire-adapted native plants. To understand how prescribed burning affects population dynamics of native perennials we need to know how burning affects the population's entire life table. We focus on a population of the purple coneflower, Echinacea angustifolia (Asteraceae), a model system for common conservative species in fragmented prairies. In this study, we report on an experiment with ten study plots growing in four vegetation types where subplots were subject to burning the spring before and after fall seeding. A Poisson regression analysis revealed that the probability of a seed recruiting to the seedling stage with a spring burn following planting was about 37% that of seeds with no burn. Vegetation type significantly influenced recruitment. Further analysis revealed that the effect of burning on recruitment differed significantly among vegetation types. We relate these results to previous findings about Echinacea reproduction under various fire regimes and discuss how burning may influence population persistence in habitat remnants.

KEY WORDS: prescribed burn, prairie, plant demography, Echinacea angustifolia