Relict populations of Lyonetia ledi Wocke, 1859 (Lepidoptera, Lyonetiidae) from the Alps indicate postglacial host-plant shift to the famous Alpenrose (Rhododendron ferrugineum L.)

Lyonetia ledi Wocke, 1859 (Lyonetiidae), was hitherto considered as a boreal species with a circumpolar distribution pattern and relict populations in isolated peat bogs north-east of the Alps (Austria, Czech Republic, Germany). In Europe it is known as a leaf-miner on Rhododendron tomentosum Stokes ex Harmaja (Ericaceae) as the primary host-plant and also Myrica gale L. (Myricaceae). The first record of L. ledi from the Swiss Alps on Rhododendron ferrugineum L., the famous Alpenrose, indicates an ancient host-plant switch during postglacial periods when R. tomentosum and R. ferrugineum shared habitat in the prealps. Conspecificity with northern populations is supported by the adult morphology and supplementing DNA barcodes (mtDNA COI gene). L. ledi is the first obligatory leaf-mining species on R. ferrugineum. Details of the life-history and habitat are described and figured. The record finally substantiates the probability of an autochthonous population in Carinthia (Austria), from where the species was recently published as new to the Alps.

Improved Mapping of Mountain Shrublands Using the Sentinel-2 Red-Edge Band

Shrub encroachment into grassland and rocky habitats is a noticeable land cover change currently underway in temperate mountains and is a matter of concern for the sustainable management of mountain biodiversity. Current land cover products tend to underestimate the extent of mountain shrublands dominated by Ericaceae (Vaccinium spp. (species) and Rhododendron ferrugineum). In addition, mountain shrubs are often confounded with grasslands. Here, we examined the potential of anthocyanin-responsive vegetation indices to provide more accurate maps of mountain shrublands in a mountain range located in the French Alps. We relied on the multi-spectral instrument onboard the Sentinel-2A and 2B satellites and the availability of red-edge bands to calculate a Normalized Anthocyanin Reflectance Index (NARI). We used this index to quantify the autumn accumulation of anthocyanin in canopies dominated by Vaccinium spp. and Rhododendron ferrugineum and compared the effectiveness of NARI to Normalized Difference Vegetation Index (NDVI) as a basis for shrubland mapping. Photointerpretation of high-resolution aerial imagery, intensive field campaigns, and floristic surveys provided complementary data to calibrate and evaluate model performance. The proposed NARI-based model performed better than the NDVI-based model with an area under the curve (AUC) of 0.92 against 0.58. Validation of shrub cover maps based on NARI resulted in a Kappa coefficient of 0.67, which outperformed existing land cover products and resulted in a ten-fold increase in estimated area occupied by Ericaceae-dominated shrublands. We conclude that the Sentinel-2 red-edge band provides novel opportunities to detect seasonal anthocyanin accumulation in plant canopies and discuss the potential of our method to quantify long-term dynamics of shrublands in alpine and arctic contexts.

Population characteristics, habitat, and conservation status of Rhododendron ferrugineum L. (Ericaceae), a glacial relict new to Poland

The first reliable information on the occurrence of <em>Rhododendron ferrugineum</em> in the Karkonosze Mts (excluding spots of directly acknowledged anthropogenic origin) was provided by A. Boratyński in 1983, but the status and origin of the plants were unknown. A recent phylogeographical study proved the natural character and relict status of the aforementioned population, which makes it the northernmost and most isolated site within the whole distribution of the species. In this study, we characterized the basic aspects of the ecology and conservation status of the population and, more specifically, focused on assessing the size of the population, general health of individuals, generative propagation ability, habitat conditions, and potential threats for the species. The population persists in the Sowia Dolina (east part of the Karkonosze Mts), in a microtopographically controlled, treeless microrefugium. Shrubs of <em>R. ferrugineum</em> are part of an acidophilous dwarf-heath plant community, similar to those occurring in the Alps and the Pyrenees, although less species-diverse. The plant community in the Karkonosze Mts has been preliminarily classified into the <em>Genisto pilosae-Vaccinion</em> alliance. The <em>R. ferrugineum</em> population consists of 68 individuals: 57 fully grown and juvenile and 11 seedlings. In 2017, 10 individuals flowered, seven of which developed fruits, while in 2018, 15 individuals produced flowers and eight developed mature fruits. Seeds collected in 2017 germinated in high numbers. Plants in the Karkonosze population hosted some fungal parasites typically found in <em>Rhododendron</em> species, but no intense disease symptoms strongly influencing plant fitness were observed. A combination of significant isolation, genetic distinctness, and high genetic diversity implies a high conservation priority for the <em>R. ferrugineum</em> population in Karkonosze. Despite the theoretical threats, including stochastic risks, the <em>R. ferrugineum</em> population seems to have been stable for a long time and, importantly, it is composed of individuals of different ages, from large flowering plants to seedlings.

First record of Exobasidium rhododendri (Fuckel) C. E. Cramer in Poland

We report here the first wild locality of <em>Exobasidium rhododendri</em> (Fuckel) C. E. Cramer in Poland. This peculiar species is an obligatory pathogenic basidiomycete, which induces formation of galls on leaves of <em>Rhododendron</em>. It was found for the first time in Poland in 2017 on <em>Rhododendron ferrugineum</em> L. plants in a population of this shrub in the Karkonosze Mts (the Sudetes range). The species was recently shown to be native and a relict. We also present a basic description of the species based on the specimens from the abovementioned locality.

Diderma meyerae. [Descriptions of Fungi and Bacteria].

A description is provided for Diderma meyerae, a myxomycete which occurs on living branches, living flowers, living and dead stems, living and dead dry fallen twigs, and dry fallen leaves. Some information on its interactions and habitats, economic impacts, intraspecific variation, dispersal and transmission and conservation status is given, along with details of its geographical distribution (Japan, Kazakhstan (Almaty Oblast), Austria, France, Germany, Italy, Norway, Russia (Karachay-Cherkess Republic, Murmansk Oblast), Spain, Switzerland, Ukraine) and associated organism and substrata (Alnus alnobetula, Alnus sp. (stem); Apiaceae indet. (stem); Calluna vulgaris, Epilobium sp., Fagus sylvatica (branch, leaf, twig), Galeopsis tetrahit (flower, twig), Gramineae indet., Juniperus communis, Plantae indet. (twig), Poaceae indet.; Rhododendron ferrugineum, Rhododendron sp. (twig), Rubus sp. (stem), Vaccinium myrtillus (twig), Vaccinium sp. and Diderma niveum).