Consequences of a chronic rust pathogen on population dynamics of Arisaema triphyllum.
Mason, Erin*,1, Jarosz, Andrew*,1, 1 Michigan State University, East Lansing, MI, USA
ABSTRACT- The consequences of disease have been demonstrated at the individual level and across species ranges. However, few studies have investigated population-level responses to disease. To measure the effects of disease on its host population, we monitored six populations of Arisaema triphyllum (L.) Schott, Jack-in-the-pulpit, and its associated systemic rust pathogen, Uromyces ari-triphylli (Schw.) Seelier (Basidiomycetes) over six years. Disease limited recruitment and altered the ratio of sexual to vegetative reproduction within populations. Growth was also reduced in diseased plants, changing the size structure within highly diseased populations and limiting the number of plants large enough to flower. While mortality did not occur immediately following infection, diseased plants displayed reduced survivorship over time. We found that high disease incidence had negative effects on population growth rates. However, disease levels displayed strong temporal cycling within most populations, and long-term effects of disease on A. triphyllum populations are difficult to predict. All populations declined in size over the course of our study, even with the fluctuations in disease incidence.
Key words: Arisaema triphyllum, population dynamics, plant-pathogen interaction, Uromyces ari-triphylli
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