Comparative assessment of reproductive traits across different habitats in the endangered Webb’s hyacinth (Bellevalia webbiana Parl.)

Abstract

To pursue a proper conservation of narrow endemic species, the knowledge of basic reproductive strategies is crucial to plan adequate conservation activities. One of the most evolutionarily relevant and threatened Italian endemic is the Webb’s hyacinth (Bellevalia webbiana Parl.). As the reproductive behaviour of this species and its connection with human impact are currently unknown, the aim of this study was to characterise the reproductive traits of the Webb’s hyacinth in contrasting habitats. All the 5 known richest populations across the species range were investigated. Their reproductive strategies were inferred by measuring inflorescence height, fruit set, seed set and P/O ratio. Reproductive features varied greatly amongst stands and also in relation to the degree of human disturbance. However, in all cases, seed sets showed low values. P/O values point towards full xenogamy and it is concluded that effective cross-pollination may be the main mode of sexual reproduction in Bellevalia webbiana. The reasons for the low reproductive performances may reside in pollen limitation, Allee effect and/or intrinsic reduced fertility of the species. Given this scenario, conservation efforts for Webb’s hyacinth should focus on maintaining large and relatively dense populations, to guarantee some chance of in situ survival.