PARENT SESSION
Poster Session 24: Agro-Ecology
Wednesday, August 10, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
A modeling study of soil temperature and moisture effects on population dynamics of Paronychiurus kimi (Collembola: Onychiuridae).
Choi, Won Il*,1, Moorhead, Daryl 2, Neher, Deborah1, Ryoo, Mun Il3, 1 University of Vermont, Burlington, VT, USA2 University of Toledo, Toledo, OH, USA3 Korea University, Seoul, Korea
ABSTRACT- The effect of soil moisture on population dynamics of Paronychiurus kimi (Collembola) was examined by combining an empirical soil moisture model with a temperature-sensitive, stage-structured population model. Field observations of soil temperature were used to drive the population model and simulations were compared to field observations of juvenile and adult densities. Simulations without soil moisture effects produced stable, inter-annual population dynamics, and a significant correlation between simulations and observations (n=13, r2= 0.18, P<0.05), but overestimated densities during much of the year. Adding responses to soil moisture improved the fit between simulations and observations (r2 = 0.40), suggesting that soil moisture is a major limiting factor on field populations of P. kimi. Moreover, an observed, temporary decline in field populations during spring could be explained partly by the effects of an herbicide, paraquat (N,N'-dimethyl-gamma,gamma'-bipyridylium dichloride) (r2= 0.45), suggesting that paraquat imposed additional limits on collembolan. Our model is among the first to demonstrate significant impacts of soil moisture and herbicide application on field population dynamics of a common, soil-dwelling collembolan species.
Key words: collembolan, soil moisture, Paronychiurus kimi, stage structured model