Print PageUnderstanding factors affecting demographic dynamics is a vital component of conservation. By discerning how vital rates change in response to population and environmental factors and their effect on population growth and structure, management strategies can be tailored to optimize conservation efforts. The perennial herb Liatris ohlingerae is a federally listed plant endemic to the Lake Wales ridge in peninsular Florida. Using data collected annually for up to 14 years from 20 populations, we assessed the influence of plant size, time since fire, and vertebrate herbivory, on four vital rates: survival, growth, probability of reproduction, and fecundity. Variation in survival and probability of reproduction were analyzed using multiple logistic regressions; growth and fecundity were examined with multiple linear regressions. The relative importance of alternative models was assessed using AICc.
Results/Conclusions
Regression analyses have revealed relationships between the vital rates and several parameters. Survival showed strong positive correlation with number of stems, stem length, and change in size. Habitat type also was an important predictor of survival. Growth was negatively correlated with prior growth, stem length, and stem number in the previous year as well as herbivory rates in the same year. Growth was positively correlated with stem number in the current year. Increasing probability of reproduction was best predicted by increasing stem length and stem number. Fecundity was best predicted by a negative correlation with stem number in the current year and positive relationships with fecundity in the previous year, as well as stem number, and stem length in the same year. These results give insight into the factors affecting demographic structure in this species and provide a crucial foundation for future efforts in modeling the demography of L. ohlingerae.
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