Habitat‐related seed germination traits in alpine habitats

Abstract

Understanding the key aspects of plant regeneration from seeds is crucial in assessing species assembly to their habitats. However, the regenerative traits of seed dormancy and germination are underrepresented in this context. In the alpine zone, the large species and microhabitat diversity provide an ideal context to assess habitat‐related regenerative strategies. To this end, seeds of 53 species growing in alpine siliceous and calcareous habitats (6230 and 6170 of EU Directive 92/43, respectively) were exposed to different temperature treatments under controlled laboratory conditions. Germination strategies in each habitat were identified by clustering with k‐means. Then, phylogenetic least squares correlations (PGLS) were fitted to assess germination and dormancy differences between species’ main habitat (calcareous and siliceous), microhabitat (grasslands, heaths, rocky, and species with no specific microhabitats), and chorology (arctic–alpine and continental). Calcareous and siliceous grasslands significantly differ in their germination behaviour with a slow, mostly overwinter germination and high germination under all conditions, respectively. Species with high overwinter germination occurs mostly in heaths and have an arctic–alpine distribution. Meanwhile, species with low or high germinability in general inhabit in grasslands or have no specific microhabitat (they belong to generalist), respectively. Alpine species use different germination strategies depending on habitat provenance, species’ main microhabitat, and chorotype. Such differences may reflect adaptations to local environmental conditions and highlight the functional role of germination and dormancy in community ecology.

The functional trait spectrum of European temperate grasslands

“…Nevertheless, we found weak functional differentiation between the high‐altitude acidic and calcareous alpine grasslands, despite having distinct differences in soil conditions and species composition. Trait‐based differences between these habitats have been found in germination traits related specifically to pH and water availability that require more experimental data (Tudela‐Isanta et al., ) than are currently available for this entire species pool. Despite the comprehensive set of traits used in this study, the lack of more specific traits, reflecting, e.g., physiological species responses, makes it possible to differentiate up to three major functional groups: (a) high‐altitude grasslands (both acidic and calcareous grasslands); (b) low‐altitude grasslands from disturbed habitats (dry grasslands and meadows); and (c) mid‐altitude Nardus ‐dominated grasslands (differentiated from (a) or (b) depending on which trait is being examined).…”

“…Nevertheless, we found weak functional differentiation between the high-altitude acidic and calcareous alpine grasslands, despite having distinct differences in soil conditions and species composition. Trait-based differences between these habitats have been found in germination traits related specifically to pH and water availability that require more experimental data (Tudela-Isanta et al, 2018) than are currently available for this entire species pool.…”

Ready for change: Seed traits contribute to the high adaptability of mudflat species to their unpredictable habitat

“…The ability of seeds of a species to disperse, persist and germinate depends on sets of trait‐based ecological responses of the species (Saatkamp et al, ). Consequently, the inclusion of seed traits can provide significant information about how communities respond to the abiotic and biotic environment (Rosbakh & Poschlod, ; Tudela‐Isanta et al, ). For instance, in a species pool of a wetland ecosystem with a fluctuating water table, if a species lacks the ability to germinate under submerged water (at constant temperature under low light and hypoxia conditions) and requires the water to recede to germinate (at fluctuating temperature under illuminated and aerobic conditions), then it will be filtered out from the local community assemblage (Keddy, ; Rosbakh, Phartyal, & Poschlod, ; van der Valk, ).…”

Variation in the seasonal germination niche across an elevational gradient: the role of germination cueing in current and future climates

“…In contrast, some species and genotypes require prolonged cold exposure to break primary dormancy and therefore germinate in spring (Footitt et al, 2013;Baskin and Baskin, 2014). Cold stratification requirements are especially common in species from high elevations (Cavieres and Arroyo, 2000;Fernández-Pascual et al, 2017;Cavieres and Sierra-Almeida, 2018;Tudela-Isanta et al, 2018). Less is known about within-species variation, but there is some evidence for stronger stratification requirements in high-elevation populations of alpine species (Cavieres and Arroyo, 2000).…”