Vegetation dormancy in the dynamics of alpine short-lived perennials: All in good time

The local population structures of two short-lived perennial species, Androsace albana and Eritrichium caucasicum, classified by ontogenetic stages were observed annually for 15 years (2009–2023) at permanent sites in the alpine belt of the North-West Caucasus. The uniquely long series of these data made it possible to discover the effects of vegetation dormancy in the life cycle of a short-lived species, which was fundamentally impossible with short series of about three to five years. Data of the “identified individuals” (A. albana) and “identified individuals from unknown parents” (E. caucasicum) types enable us to calibrate the corresponding matrix models of discrete-structured population dynamics and obtain the so-called annual population projection matrices (PPMs). The analysis of PPMs by mathematical means yields various quantitative characteristics of the monitored object, in particular, the viability measure of the local population. However, the revealed effects of vegetation dormancy make changes to the data series and raise the issue to revise the previous models and ensued characteristics. We show that including an additional state of death or vegetation dormancy into the life cycle, which is quite a logical move from the model’s viewpoint, does not make any sense in the task of assessing the population viability. When adjusted to fit the revised data, the calibration procedure, does naturally increase the previous estimates of the viability measure, thereby confirming an important role the vegetation dormancy plays as a mechanism to adapt the plant for stressful environment.