Plant litter feedback and population dynamics in an annual plant,<Emphasis Type="Italic"> Cardamine pensylvanica</Emphasis> |
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Authors: | J Molofsky J Lanza E E Crone |
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Institution: | (1) Department of Botany and Agricultural Biochemistry, University of Vermont, Burlington, VT 05405, USA e-mail: jmolofsk@zoo.uvm.edu Tel.: +1-802-656-0430, Fax: +1-802-656-0440, US;(2) Department of Biology, University of Calgary, Calgary, Alberta, T2N 1N4, Canada, CA |
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Abstract: | The presence of litter has the potential to alter the population dynamics of plants. In this paper, we explore the effects
of litter on population dynamics using a simple experimental laboratory system with populations of the annual crucifer, Cardamine pensylvanica. Using a factorial experiment with four densities and three litter levels, we determined the effect of litter on biomass
and plant fecundity, and the life stages responsible for these changes in yield. Although litter had significant effects on
seed germination and on seedling survivorship, we show, using a population dynamics model, that these effects were not demographically
significant. Rather, the potential effect of litter on population dynamics resulted almost entirely from its effect on biomass.
Persistent litter suppressed plant biomass and apparently removed the direct density effect present in the absence of litter.
Thus, litter changed the shape of the recruitment curve from slightly humped to asymptotic. In addition to changing the shape
of the recruitment curve, litter reduced the carrying capacity of the populations. Thus, the population dynamics model indicated
that not all statistically significant responses were dynamically significant. Given the potential complexity of litter effects,
simple population models provide a powerful tool for understanding the potential consequences of short-term responses.
Received: 8 September 1999 / Accepted: 5 April 2000 |
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Keywords: | Cardamine pensylvanica Delayed density dependence Density Litter Plant population dynamics |
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