Fungal Diversity of Native and Alien Woody Leguminous Plants in the Middle Urals

The biodiversity of wood-inhabiting fungi on woody leguminous plants (WLPs) growing in the Middle Urals (Russia) has been studied for the first time. From 2002 to 2022, in Sverdlovsk oblast as a model region, 136 species of wood-inhabiting fungi were identified on WLPs: 127 species of Basidiomycota and 9 species of Ascomycota. Fungi develop on 12 out of 20 species of WLPs. The largest number of fungal species was found on the alien Caragana arborescens (115 species/84.5% of the total number of species), while two species were collected on Caragana decorticans, C. ussuriensis, and Laburnum alpinum each and one species was collected on Genista florida. A total of 122 species of fungi were found on nine alien WLPs, which is 4.1 times more than on three native species. The largest number of substrate-specific fungal species can be found to develop on C. arborescens (85/62.5%), four species on Chamaecytisus ruthenicus (2.9%), three species on Maackia amurensis (2.2%), two on Genista tinctoria and Robinia pseudoacacia each (1.5%), and one species on Caragana ussuriensis (0.7%). Nectria cinnabarina develops on the maximum number of substrates, seven WLP species; Xylodon sambuci on six species; and Peniophora cinerea and Schizophyllum commune on four species. In contrast, 71.3% of fungal species were found on one WLP species, and 27.2% of species are characterized by a single finding. For the first time for Sverdlovsk oblast, 14 fungal species are indicated, of which 86% were found in the parks of Ekaterinburg city and tree-lines along the roads, but only 14% were in natural conditions. In order to reveal the latitudinal–zonal specificity for the distribution of species richness of the WLP associated mycobiota, we use Aphyllophoroids as the largest group of fungi among all analyzed (75% of species), and Caragana arborescens, or Siberian peashrub is the richest plant substrate. Changes in the fungal diversity were studied along a meridional transect stretching for 800 km along 60° E, from the middle boreal subzone of Sverdlovsk oblast to the steppes of Chelyabinsk oblast (Russia) and Kostanay oblast (Kazakhstan). In each of the five vegetation zones/subzones, as well as in Ekaterinburg city, six sites were studied, the area of which varies from 0.9 to 6.8 ha. The aboveground phytomass of C. arborescens is maximal in the forest steppe (8.9–11.7 t/ha), and minimal at the edges of the transect (2.4–5.8 t/ha). A positive correlation was found between the aboveground plant phytomass and the species richness of mycobiota, while there was no correlation with climatic parameters. Notable differences were found in Ekaterinburg city: the Siberian peashrub phytomass was two times lower than in the forest steppe, but the species richness of mycobiota was similar to the forest steppe. A similar result was obtained for the α diversity (average number of fungal species at the sites and Shannon index) of mycobiota: an increase in the parameters from the middle boreal subzone to the forest steppe and a decrease in the steppe. The Whittaker and Czekanowski–Sørensen indices (β diversity) increase towards the steppe, which is due to a strong relationship with the mean annual temperature and precipitation. A range of fungal species gravitating towards northern, southern, and urbanized conditions has been revealed. In the north of transect, local species of fungi predominate, while in the south and in Ekaterinburg city, the role of biogeographically distant (alien) taxa is high. In this regard, the species composition of mycobiota of Siberian peashrub is divided into two clusters, northern (boreal) and southern (nemoral-steppe) ones, including Ekaterinburg city. To the south, the species richness of pathogenic fungi increases, but this parameter does not correlate with the C. arborescens phytomass. In plantings of invasive Siberian peashrub, the species richness of the poroid fungi is similar to that of the corticioid fungi at the local and regional level, which differs significantly from natural conditions. A high level of pathogenic fungi was also revealed compared to natural conditions. The results can be used to optimize the conception of Greenway planning in Ekaterinburg city and help prevent a number of environmental problems arising after the rapid implementation of the strategy for developing the city and the surrounding areas.