Format: ORAL

Clara Espinosa del Alba1, Eduardo Fernndez-Pascual1, Borja Jimnez-Alfaro???????1

IMIB Biodiversity Research Institute, (Principado de Asturias – Universidad de Oviedo – CSIC), Mieres, Spain

The seed regeneration niche encloses 4 main stages (dispersal, persistence, germination and seedling establishment) which are regulated by a complex array of physiological and environmental cues. Understanding the regeneration niche in high-mountain ecosystems is important to track species responses and community dynamics under current and future climate conditions. However, we know very little about the regeneration processes that occur in Mediterranean high mountain vegetation, which faces increasing summer drought periods. Here, we review the topic combining published literature and results from our own research in Iberian mountains. We found inconsistent results in dispersal studies, some of them reporting short-distance dispersal limitation among populations, while others suggesting dispersal-based metacommunities. Our results support that dispersal may not be limiting at the regional level and that community composition is mainly explained by soil properties related to water holding capacity. Seed persistence has rarely been studied, but our data suggest that it is highly species-specific and modulated by microhabitat conditions. Germination is the more studied, showing a general pattern of immediate germination if water is available, even at low temperatures, with complementary effects of cold stratification in some species. Our results support this general trend and provide new insights about drivers such as light, alternating temperatures and soil water potential. Finally, in concordance with existing literature, seedling establishment appears to be the most vulnerable stage, with low chance of survival in the field and in controlled laboratory conditions. Literature suggests that timing of emergence is strongly influenced by temperature cycles, and we found a pattern of increasing radicle length in species linked to warmer microhabitats. In summary, the success of seed regeneration in Mediterranean high mountains seems to be primarily limited by water stress, especially during germination and seedling establishment.