PARENT SESSION
Poster Session 20: Invasive Species
Wednesday, August 10, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal

Reproductive biology of Lespedeza cuneata.

Haller, Sarah^*,1, ¹ William Jewell College, Liberty, MO, USA

ABSTRACT- Introduced species pose a threat to ecosystems as they have the potential to alter system functions and species interactions. Used extensively as erosion control, wildlife habitat, and for forage crop, Lespedeza cuneata (Dumont) G. Don (sericea lespedeza) is an introduced species that is now considered a noxious weed. Knowledge regarding pollination and breeding systems in this species is needed to better understand its reproduction, effects on invaded communities, and potential management regimes. As a result, this research investigates the reproductive biology of L. cuneata including pollinator visitation, seed set, and temporal and spatial variation. Data collected in 2003 and 2004 demonstrates a positive relationship between plant biomass and seed production. In addition, L. cuneata produced seeds from both chasmogamous (open, potentially cross pollinated flowers) and cleistogamous flowers (closed, self-fertilizing flowers) in 2003 and 2004, with significantly more seeds from cleistogamous flowers in both years. Seeds from cleistogamous flowers provide reproductive assurance for L. cuneata while seeds from chasmogamous flowers provide greater genetic diversity. The number of cleistogamous seeds produced significantly decreased in 2004, but the number of chasmogamous seeds and the total number of seeds showed no significant difference between years. The variation in plant biomass and cleistogamous seed set between 2003 and 2004 could be due to changes in environmental conditions (i.e. rainfall). Additional data will be analyzed for cross site comparisons for 2004.

Key words: Lespedeza cuneata, invasive species, reproductive biology