Genetic differentiation among populations of the threatened Bellevalia webbiana (Asparagaceae) and its consequence on conservation

Abstract

The narrow central Italian endemic and threatened Webb's hyacinth (Bellevalia webbiana), a perennial herb, is a clear example of a species that has disappeared from several localities due to the development of human settlements. We characterized population genetics of this species to infer possible threats to its viability. We used a dominant DNA fingerprinting approach to infer genetic relationships among the five richest populations known for this species (each with N > 50 individuals). We highlighted phenomena of genetic erosion, with values of intrapopulation-gene-diversity quite similar across all populations (mean value 0.113), but a mean F st value only slightly below the mean found in other plant species using similar approaches. Despite an overall genetic similarity among populations, a population from Faenza (Emilia-Romagna) is clearly separated from all the others on genetic grounds, and may be defined as an Evolutionarily Significant Unit, worth of special conservation attention. Interestingly, this latter population is also behaving differently from all the others in terms of both vegetative and reproductive functional strategies. Our results highlight the relevance of evolutionary approaches to conservation biology for preserving a genetic diversity linked to local adaptations.

An Integrated Taxonomic Approach Points towards a Single-Species Hypothesis for Santolina (Asteraceae) in Corsica and Sardinia

“…A full ESU, as defined by Guia and Saitoh [66] based on a concept previously theorized by Ryder [67], is a population showing both genetic and adaptive variation. In addition, an ESU represents a unit with a strong evolutionary potential, relevant for conservation purposes [68]. However, from a morphological point of view, the two populations from southern-western Sardinia are far from similar (Figure 3).…”

Combining conservation status and species distribution models for planning assisted colonisation under climate change

“…For example, Cerastium utriense would experience a dramatic range loss due to climate change, but AC must be informed by its strict association with specific substrata and ecological conditions, as it lives only on ultramafic substrates (Marsili et al., 2009). Bellevalia webbiana shows inter‐population genetic differentiation, so that an evolutionarily significant unit (ESU) distinct from others was detected near Faenza (Peruzzi et al, 2021). However, evidence for genetic adaptation to climate change is still relatively scarce (Foden et al., 2019) and phenotypic shifts associated with contemporary climate change seem to be due to phenotypic plasticity, rather than to genetic microevolutionary responses that are much more difficult to be detected (Merilä & Hendry, 2014; Thompson et al., 2013).…”

“…Bellevalia webbiana shows inter-population genetic differentiation, so that an evolutionarily significant unit (ESU) distinct from others was detected near Faenza (Peruzzi et al, 2021). However, evidence for genetic adaptation to climate change is still relatively scarce (Foden et al, 2019) and phenotypic shifts associated with contemporary climate change seem to be due to phenotypic plasticity, rather than to genetic microevolutionary responses that are much more difficult to be detected (Merilä & Hendry, 2014;Thompson et al, 2013).…”

Potential climatic and elevational range shifts in the Italian narrow endemic Bellevalia webbiana (Asparagaceae) under climate change scenarios

“…Then, even admitting that potentially suitable areas at higher elevations could effectively host B. webbiana and that this species could colonise these areas by natural or assisted migration (Brodie et al 2021), then this would imply an increasing connection between the two currently disjunct population groups. This increasing connection would, in turn, promote a potential loss of the genetic and functional differentiation documented for some populations (Astuti et al 2018(Astuti et al , 2019Peruzzi et al 2021). Moreover, considering that the actual AOO documented for Bellevalia webbiana amounts to just 47 2×2 km cells (of which only 24 were confirmed in recent times) and that forest expansion in Apennine mountains could further reduce the availability of open habitats (Gargano et al 2012), this species shows evident conservation concerns.…”

“…Despite the small distribution range, this species is linked to relatively common habitat types, since it typically grows in open fields and meadows, wood margins, olive groves, and vineyards (Gestri et al 2010). Recent studies investigated the population genetics (Peruzzi et al 2021), functional traits (Astuti et al 2019), and reproductive performance (Astuti et al 2018) of the five largest populations known for this species. These studies highlighted some differentiation in the population located at the upper NE limit of the species range, around Faenza (Ravenna).…”