Deep roots delay flowering and relax the impact of floral traits and associated pollinators in steppe plants

Abstract

Strong seasonality in abiotic harshness and pollinator availability shape the reproductive success of plants. Plant species can avoid or can tolerate harsh abiotic conditions and can attract different pollinators, but it remains unknown (i) which of these capacities is most important for flowering phenology, (ii) whether tolerance/avoidance of abiotic harshness reinforces or relaxes the phenological differentiation of species attracting different pollinators. We assembled possibly the first functional trait database for a North African steppe covering 104 species. We inferred avoidance of harshness (drought) from dormancy, i.e. annual life-span and seed size. We inferred tolerance or resistance to harshness from small specific leaf area, small stature, deep roots and high dry matter content. We inferred the type of pollinators attracted from floral colour, shape and depth. We found that avoidance traits did not affect flowering phenology, and among tolerance traits only deep roots had an effect by delaying flowering. Flower colour (red or purple), and occasionally flower depth, delayed flowering. Dish, gullet and flag shape accelerated flowering. Interactive effects however were at least as important, inversing the mentioned relationship between floral characters and flowering phenology. Specifically, among drought-tolerant deep-rooted species, flowering phenologies converged among floral types attracting different pollinators, without becoming less variable overall. Direct and interactive effects of root depth and floral traits explained at least 45% of the variance in flowering phenology. Also, conclusions on interactive effects were highly consistent with and without including information on family identity or outliers. Overall, roots and floral syndromes strongly control flowering phenology, while many other traits do not. Surprisingly, floral syndromes and the related pollinators appear to constrain phenology mainly in shallow-rooted, abiotically little tolerant species. Lack of abiotic tolerance might hence constrain accessible resources and thereby impose a stronger synchronization with biotic partners such as pollinators.

Restoration techniques for degraded steppe courses: diachronic study in the Laghouat region (southern Algeria)

“…The higher values of litter is the consequence of the mortality of plants -annual and perennial -as a react toward the climate harshness. This leads to a traded-off between their vegetative and owering phenology and consequently, they might complete their life cycle before the drought period (Berrached et al, 2017). The same results has been showed in the decompacted plots with manure.…”

Reproductive phenology as a dimension of the phenotypic space in 139 plant species from the Mediterranean

“…Moreover, within the group of herbaceous perennials, we showed a clear relationship between SWDSMP and leaf traits. Similarly, Craine et al (2012) found that flowering under low water availability period is associated to high leaf density and Berrached et al (2017) found that under drought conditions, deep rooted species tend to flower late in the season. In our case, the use of LW and δ 13 C, which are commonly used to describe water use strategies, didn't lead to similar conclusions.…”

“…2010) Ansquer et al (2009),Duru et al (2009). andVile et al (2006) found positive relationships between LMA, LDMC, flowering date and dispersal date for 31 herbaceous species, 19 grass species and herbaceous species respectively, while no relationship was found between these traits byJia et al (2011) on 48 alpine herbs orBerrached et al (2017) on …”