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

Understanding the interrelations of native and introduced species in the Hawaiian lowland wet forest through seed rain and soil seed bank quantification.

Vasquez-Radonic, Lucero^*,1, Ostertag, Rebecca ², ¹ The University of Texas at El Paso, El Paso, Texas, USA² The University of Hawaii at Hilo, Hilo, Hawaii, USA

ABSTRACT- Many Hawaiian ecosystems have been drastically impacted by human presence mainly through the introduction of non-native species. The impact of introduced species is particularly strong in the lowland wet forest, where little research has been conducted to understand the mechanisms by which introduced species dominate and control the ecosystem. In order to understand the structure of this forest and the ways introduced species may out-compete native species, eight comparison plots, four control and four removal plots, were created in an invaded Hawaiian lowland wet forest. We examined the relationship between seed presence, through quantification of the seed rain and the soil seed bank, and the establishment of native and introduced seedling species. We predicted that the overall amount of seeds will be higher in the control plots than in the removal plots because its structure makes this area a more suitable habitat for birds, a major seed dispersal agent. We also hypothesized that seed rain will be the main contributor of germinants in the control plots, but the seed bank will be the main contributor of germinants in the removal plots. Preliminary observations show that at the removal plots, introduced species dominate the seedling population although no introduced adult specimens are present within the plot. We hypothesize that such conditions are due to the role of the seed bank, while the seed rain is a mechanism for establishment of both native and introduced species. Therefore, we suggest that most introduced species get established through the seed bank, especially after disturbance. The results obtained may help us understand the competitive success of native and introduced species at this site, providing us the tools to develop alternative control methods that could be applied at the different plant life stages.

Key words: Hawaiian ecosystem, Invasive species, Seed rain, Seed bank