Reproductive traits variation in the herb layer of a submediterranean deciduous forest landscape

Abstract

In submediterranean ecosystems macroenvironmental\ud stress gradients (winter cold stress and summer drought stress linked to elevation, slope aspect, and angle) affect forest distribution and composition. We hypothesized that in the herb layer of submediterranean deciduous woods (central Apennines), environmental stress gradients, jointly with\ud overstory type, determine patterns of reproductive\ud strategies, which are supported by different acquisitive/\ud retentive traits. We used indicator species analysis, canonical redundancy analysis, and variance partitioning to identify the main gradients of trait variation, detect trait patterns, and assess the contribution of each environmental variable to the\ud explanation of trait variability. Our results indicated\ud that reproductive traits, related to resource acquisition\ud and conservation strategies, showed a pattern mainly linked to the joint effect of altitude and overstory type and, second, to slope aspect. Species with both sexual and vegetative propagation, more abundant than those reproducing only sexually, did not show any trend. Below 1,000 m a.s.l. the long-lasting growing season favored traits aimed at efficient light and soil resource acquisition\ud and space exploitation (e.g., persistent green leaves,\ud runners, tap roots, medium sized seeds) that support a long reproductive cycle. Over 1,000 m a.s.l. the intense and long-lasting winter cold stress and the shorter growing period fostered traits aimed at fast growth and reproduction (e.g., self-pollination, low seed weight, spring and overwintering green leaves), and at stress tolerance (rhizomes, bulbils)

Disentangling the Ecological Determinants of Species and Functional Trait Diversity in Herb-Layer Plant Communities in European Temperate Forests

“…For example, the authors of [6] demonstrated that forest understory vegetation is more related to soil than to climate towards the cold distribution margin of European beech. Furthermore, topography (aspect and slope; [11,12]) and associated microclimatic conditions (air temperature and humidity; [13,14]) can also be decisive for the diversity and abundance of forest vegetation. In comparison to non-forest vegetation (e.g., grasslands) with less vertically stratified structure, the interplay between different vegetation layers in the forest ecosystem (i.e., tree, shrub and herb layer) additionally increases the complexity of the dependencies of herb-layer vegetation on ecological factors coming from above (light) and below (soil moisture and nutrients).…”

Pedo-climatic and land use preferences of Gentiana lutea subsp. lutea in central Italy

“…Light radiation is not only a beneficial resource, but can also be a detriment, as it determines evaporative water demand and the potential for drought stress (Pausas & Austin 2001). In fact, on south-facing slopes, the greater radiation in summer dramatically reduces the soil water content (Joffre & Rambal 1993), posing one more stress factor faced by plants in mountain areas (Catorci et al 2013c).…”

How large-scale geographic factors affect the different dimensions of functional diversity: evidence from the beech forest herb layer (Apennines, Italy)

“…In particular, we expected that increasing intensities of stress cause convergence of traits related to stress tolerance and avoidance strategies, in line with the SDH, and of traits linked to reproductive strategies aimed to overcome sexual recruitment problems. Cold stress indeed proved to cause a deviation from optimum temperatures for growth, leading to a syndrome of plant traits that includes very fast development, high rates of metabolism, short tissue duration, substantial below-ground storage organs (Körner 2016), as well as clonal growth organs and a self-pollination strategy to overcome sexual recruitment problems and to face unpredictable annual climatic fluctuations (Catorci et al 2013). Drought stress, reducing soil water content (Joffre & Rambal 1993), fosters drought tolerance strategies, e.g.…”

“…Moreover, summer drought stress shortens the time available for plants to complete the vegetative cycle, therefore may foster also drought avoidance strategy, e.g. filtering a set of traits linked to resource acquisition and fast reproduction, such as spring/early summer flowering besides spring green and overwintering green leaves (Catorci et al 2013), low plant height (Nunes et al 2017), high Specific Leaf Area (Gross et al 2013), and vegetative propagation by bulbils (Lee & Harmer 1980;Catorci et al 2013).…”