[Ipmpack-users] modelling a gender-switching iteroparous herb

[Christopher Heckel]

Hello all,


I would like to use IPMs to model the population dynamics of a plant that is not only an iteroparous perennial, but also exhibits size-dependent gender switching.  Generally for this species (Arisaema triphyllum) plants progress from non-flowering to male-flowering to female-flowering over the course of several years depending mainly on biomass accumulation.  However, plants also can retrogress to previous states; for example, a plant that was female in year t could return as male in year t+1.


My questions:


1. I think I need to set this up as a stage-size-dependent IPM but I am unsure how to allow individuals to move back and forth between stages.


2. I can use polytomous logistic regression to find size-based transition probabilities among the three stages with greater power compared to a series of binomial logistic regressions.

    a. Is polytomous log-reg appropriate for this?

    b. Could IPMpack tools handle this?


Thanks to all for any suggestions to help get me moving forward.


Christopher Heckel


PhD candidate

University of Pittsburgh


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