Current status of the rare British endemic Gentianella amarella subsp. occidentalis, Dune Gentian (Gentianaceae)

Gentianella amarella subsp. occidentalis, Dune Gentian, is a rare annual of dune slacks endemic to Western Britain. Its current status was compared to historic records. A maximum of 2250 plants were found in ten subpopulations in four sites in 2019-2020. It was not refound in three sites and 15 subpopulations. It is assessed as IUCN threat category ‘Endangered’. Its primary vegetation type is SD14d Salix repens - Campylium stellatum dune slack Festuca rubra subcommunity, within which it favours short, open structure on dry, low nutrient soils. Conservation requires managing and creating its niche in the dune slacks.

Host Plant Selection in Phyllonorycter Species Living on Willows and Their Hybrids (Lepidoptera: Gracillariidae)

Own knowledge on host plants and on the breadth of the trophic specialization of central European species ofPhyllonorycterHübner, 1822 living onSalixspp. obtained over the past 60 years are presented. A total of 8 species were evaluated and divided into four groups after their trophic relationships; monophagous species:Phyllonorycter quinqueguttella(Stainton, 1851) onSalix repenss. l., andP. viminetorum(Stainton, 1854) onSalix viminalis(here only provisorly due to the small number of reared specimens); narrowly oligophagous species:P. dubitella(Herrich‑Schäffer, 1855) andP. salicicolella(Sircom, 1848), both onSalixspecies of the sectionCapreae; oligophagous species:P. hilarella(Zetterstedt, 1839) andP. salictella(Zeller, 1846) on manySalixspecies, each with different trophic preferences; broadly oligophagous species:Phyllonorycter connexella(Zeller, 1846) andP. pastorella(Zeller, 1846) developing onSalixandPopulusspecies. The hybrids are also used as host plants, and the laying females positively respond to them as well as to the biologicalSalixspecies, if at least one of the parental species is the usual host of the relevantPhyllonorycterspecies. The data on host plants reported by other authors are compared.

Simulated mammal browsing and host gender effects on dual mycorrhizal Salix repens

We studied effects of simulated browsing and host plant gender on mycorrhizal status of dioecious Salix repens, forming both ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) symbioses. Owing to their lower biomass production, AM fungi may require less carbon from the host and have a competitive advantage over ECM fungi when carbon availability is reduced. Further, in dioecious plants, females have generally higher reproduction costs than males. Hence, herbivory may be especially detrimental to female plants and their ECM symbionts in favour of AM symbionts. Fifty percent shoot clipping increased the number of vegetative shoots but reduced the proportion of flowering shoots equally in male and female hosts. Despite clipping, ECM and AM colonization remained unchanged. However, slightly reduced soil fungal biomass was found in clipped patches of male S. repens. Our novel finding of AM spores occurring in the ECM fungal mantle of S. repens roots suggests that both mycorrhizal partners may coexist in the same root segment. Since no interaction between gender and clipping in fungal parameters was detected, we conclude that female and male S. repens are equally preferable hosts for fungal symbionts, even when carbohydrate availability has been decreased because of herbivory.