Pressing flowers between pages…
The effects of herbivore damage on plant reproductive success are most often assessed by counting fruit and seed production over a few years. Long-term, demographic data sets can be extraordinarily useful in elucidating patterns that cannot be revealed within the timeframe of a typical, 2-4 year project. I have monitored the demography of several populations of two long-lived, perennial plants, Sticky Polemonium (Polemonium foliosissimum) and Scarlet Gilia (Ipomopsis aggregata) in and around the RMBL, off and on, for over 12 years for each species. Both are subject to frequent predispersal seed predation and herbivory by deer which sometimes reduces their annual reproductive success to zero. The two species are uniquely different in that one, Scarlet Gilia, is a long-lived but monocarpic perennial and the other, Sticky Polemonium, also a long-lived perennial, exhibits a rare breeding system (gynodioecy) in which some individuals are typical, hermaphrodites while others function only as females. These differences in reproductive strategies, along with other life-history traits, provide exciting opportunities to ask questions about the effects of herbivory on demographic processes, sex-ratios, and life-history traits. Over the next five years, I aim to accomplish two overarching goals: 1) analyze my long-term data sets for each species to reveal the ways in which herbivore damage affects life history traits and population growth rates; and 2) continue to monitor populations of Sticky Polemonium to examine the stability of sex ratios within and among populations over time and assess if herbivory levels are correlated with changes in sex ratios.