Unravelling some factors affecting sexual reproduction in rock-specialist shrub: Insight from an endemic Daphne arbuscula (Thymelaeaceae)

Abstract

The role of endemic species in global biodiversity is pivotal, and understanding their biology and ecology is imperative for their fitness and long-term survival, particularly in the face of ongoing climatic oscillations. Our primary goal was to investigate the sexual reproduction level of the endangered Western Carpathian endemic Daphne arbuscula (Thymelaeaceae), which inhabits extreme rocky habitats, and to comprehend the influence of specific factors on its reproductive success. We conducted the research across four populations, varying in size and environmental conditions. Over two years, we monitored flower and fruit production, analyzed genetic variability within and among populations, and studied pollination mechanisms. Daphne arbuscula proved to be strictly self-incompatible, with significant variations in flower and fruit production among populations and seasons. The average fruit production percentage consistently remained below 50% across populations, indicating challenges in sexual reproduction. Cold and harsh weather during the reproductive phase had a substantial negative impact on sexual reproduction efficacy, leading to decreased fruit production. Nevertheless, several individuals in sheltered microhabitats displayed significantly higher fruit production, ranging from 60% to 83%, emphasizing the critical role of microhabitat heterogeneity in sustaining sexual reproduction in this species. We found no pronounced differences in genetic diversity within or among populations, suggesting that genetic factors may not critically influence the reproductive success of this endemic species. The implications of our findings might be of paramount importance for the long-term survival of D. arbuscula and offer valuable insights for the development of effective conservation strategies for this species.

Environmental heterogeneity structures root‐associated fungal communities in Daphne arbuscula (Thymelaeaceae), a shrub adapted to extreme rocky habitats

“…Valachovič & Jarolímek, 1994;Valachovič & Mucina, 2004) or in relict calcicolous pine forests (alliance Pulsatillo slavicae-Pinion sylvestris Fajmonová 1978 (Uhlířová & Bernátová, 2003)). Our recent study indicates that this site microclimatic heterogeneity has also an impact on species' reproductive abilities (Gajdošová et al, 2024). The environmental heterogeneity of D. arbuscula sites and the detection of diverse fungal entities within the plant tissues present compelling questions regarding the interactions between the mycobiome, the host plant and the environment.…”