PARENT SESSION
Poster Session 10: Restoration and Adaptive Management
Tuesday, August 9, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal

Priority effects along a nitrogen gradient in an early successional grassland.

Aschenbach, Todd^{*,1, 2}, ¹ University of Kansas, Lawrence, KS² Kansas Biological Survey, Lawrence, KS

ABSTRACT- Timing of species introductions during community development can impact community composition through priority effects. To evaluate the role of priority effects in regulating species establishment along a natural nitrogen gradient, 30 prairie forb species were added to 40 plots in an early successional grassland in eastern Kansas over a two-year period. In treatment 1, all 30 species were seeded in 1999. In treatment 2, 10 species were seeded in 1999 followed by the remaining 20 species in 2000. Differences in seeded species cover between treatments were compared along the nitrogen gradient to evaluate the importance of priority effects relative to productivity. Analyses indicate that species that were seeded earlier in succession exhibited significant increases in cover (P<0.050) compared to species that were seeded later in succession. Analyses of seeded species cover along the nitrogen gradient indicate that differences between treatments decreased with increasing soil nitrogen. Results suggest that priority effects are important in mediating biotic interactions during community assembly, however, abiotic resources may determine the magnitude of this effect.

Key words: priority effects, community assembly, productivity, nitrogen