Links between shoot and plant longevity and plant economics spectrum: Environmental and demographic implications
Abstract
The tacit assumption of functional ecology is that traits affect plant fitness. However, this link is mediated by demography, e.g. specific leaf area is not affecting changes in abundance directly but through vegetative multiplication or generative reproduction of plants it means via demographic processes.
We propose that in herbaceous perennials, architectural traits that capture shoot development constitute simple morphological surrogates of a number of demographic functions (shoot lifespan, lateral spread, multiplication rate). A shoot is a reiterated basic unit of a plant body in herbs and is easily recognizable as an individual.
We propose that potential shoot lifespan (shoot cyclicity) may serve as a simple character relevant to demographic processes of clonal herbs while whole plant longevity plays a similar role for non-clonal herbs. Therefore we examined relationships of shoot and whole-plant lifespans with a key trait of the plant economic spectrum (specific leaf area, SLA) for a large set of Central European temperate zone herbs.
We also investigated whether shoot and whole-plant lifespan are non randomly distributed along environmental gradients, using indicator values and their distribution among plant community types. Finally, we analysed whether shoot cyclicity underlies differences in temporal turnover of plants in species-rich meadows.
Our analyses showed that fast-growing species had shorter shoot and/or plant lifespan and preferred more productive environmental conditions, but the relationship was not strong. In addition, the two lifespan measures were independent of each other, indicating that shoot lifespan captures a rather different aspect of plant demography than whole-plant longevity.
Turnover of perennial plants with annual shoots in meadow community was much higher than that of plants with long-lived shoots.